-
حرية الوصول المقاله
1 - Synthesis structural and anti-microbial characterization of nanostructured doped tin oxide
Achyutmohan Chaudhury Utsa Debnath Sujay Munshi Goutam Basak Avigyan Dutta Suvadip Masanta Achintya Singha Aritra Banerjee Debtanu Ghosh Partha Chatterjee Apurba Kanti DebNanocrystalline boron doped tin oxide and boron and silver co-doped SnO2 was successfully prepared by using simple sol-gel method. The structural property of as-prepared nanocrystalline materials was investigated by using X-ray powder diffraction, Raman spectroscopy, Fo أکثرNanocrystalline boron doped tin oxide and boron and silver co-doped SnO2 was successfully prepared by using simple sol-gel method. The structural property of as-prepared nanocrystalline materials was investigated by using X-ray powder diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy and scanning electron microscopy. The infrared spectra of the prepared samples showed an incorporation of B and Ag in the SnO2 nanocrystals. The X-ray powder diffraction pattern of the as prepared sample demonstrated the formation of a rutile structure of SnO2 nanocrystallites with particle size of 35 nm and 98 nm for boron doped and co-doped samples respectively. The two different Sn-O bond distances are found to be varying in a different manner for the doped samples unlike pristine samples. A significant lattice microstrain was observed for co-doped samples indicating local lattice distortion. The prepared samples showed significant anti-microbial activities against some Gram-Positive & Gram-Negative bacteria in both water and DMSO medium. The prepared materials can be effective for water remediation. تفاصيل المقالة -
حرية الوصول المقاله
2 - Application of four-wave mixing for estimation of nonlinear parameters in compact ring cavity laser based on Bi-EDF
Sharifeh Shahi Sasan Soudi Yalda Ghorbani Bahareh Khaksar jalali Sulaiman Wadi HarunOne of the main degradation effects of optical fibres with dense channel width and poor chromatic dispersion on the fiber is four-wave mixing (FWM). Cross talk produced by four-wave mixing in optical fibers limits the efficiency of long-distance wavelength-division mult أکثرOne of the main degradation effects of optical fibres with dense channel width and poor chromatic dispersion on the fiber is four-wave mixing (FWM). Cross talk produced by four-wave mixing in optical fibers limits the efficiency of long-distance wavelength-division multiplexing (WDM) optical communication systems, which can be regulated for non-linearity purposes in optical telecommunication, particularly when channel wavelengths are set near the zero-dispersion wavelength of optical fibers. As a result, a small fiber segment with a high nonlinearity can be used to support the FWM. Using the four-wave mixing method, the experimental set-up of a compact fiber ring laser based on different lengths of nonlinear Bismuth-Erbium doped fiber (Bi-EDF, 181 and 215 cm) is used in this paper. Via the degenerate four-wave mixing effect, these two gain nonlinear media have been successfully used to stabilize a dual-wavelength fiber laser with and without nonlinear photonic crystal fiber (PCF) at room temperature for and n2 estimation of nonlinear parameters and FWM performance of optical fiber. Experiments show that using a high non-linear bismuth-erbium doped fiber (Bi-EDF) in implementing an FWM program for non-linear PCF parameters has specific and unique benefits. Furthermore, the FWM effect can be used for signal amplification, wavelength transfer, phase conjugation, and high-speed optical switching. The proposed configuration's special function is explained by the Bi-EDF and PCF fiber's coupled relationship in FWM scattering. تفاصيل المقالة -
حرية الوصول المقاله
3 - Electrodeposition of cobalt oxide thin films for potential applications
Sandra Augustine Azubike Ekpunobi Diemiruaye JerohCobalt oxide thin films at varied molar concentrations were prepared by electrodeposition technique. Ultraviolet-Visible (UV/VIS) analysis conducted on the grown films revealed blue shift in the absorption edge at increased molar concentrations, which is a consequence o أکثرCobalt oxide thin films at varied molar concentrations were prepared by electrodeposition technique. Ultraviolet-Visible (UV/VIS) analysis conducted on the grown films revealed blue shift in the absorption edge at increased molar concentrations, which is a consequence of band gap widening. The band gap values (3.65 eV to 3.85 eV) in this research are greater than the value (2.4 eV) for the bulk phase of cobalt oxide. This increase in band gap can be likened to higher concentration effect and quantum-size phenomenon. Scanning Electron Microscopy (SEM) analysis indicated a porous nature for the material, suggesting its ability in absorbing ultraviolet (UV) radiation, thus confirming its use as an absorber material for solar cells fabrication. Energy Dispersive X-ray (EDX) study confirmed the growth of cobalt oxide. X-ray diffraction (XRD) analysis confirms the crystalline nature of the films with grain sizes within the range of 0.7 nm to 1 nm for varied molar concentrations. Electrical studies reveal a linear relationship of resistivity values with molar concentrations, while the conductivity values reveal inverse relationship with molar concentration. تفاصيل المقالة -
حرية الوصول المقاله
4 - Effect of different sizes of balls on crystalline size, strain, and atomic diffusion on Cu-Fe nanocrystals produced by mechanical alloying
Mohammad Reza Vaezi Seyed Hesam Mir Shah Ghassemi Ali ShokuhfarAbstractEffects of ball diameter on the crystalline size, induced strain, and atomic diffusion in Cu-50%Fe immiscible alloy system have been investigated. Milling parameters affect atomic diffusion in binary or ternary systems separately. The aim of this research work i أکثرAbstractEffects of ball diameter on the crystalline size, induced strain, and atomic diffusion in Cu-50%Fe immiscible alloy system have been investigated. Milling parameters affect atomic diffusion in binary or ternary systems separately. The aim of this research work is to prove the fact that ball diameter is an important parameter. It is shown that different diameters can change milling power, and consequently, the final crystalline size and atomic diffusion can alter. X-ray diffraction and scanning electron microscopy were used to analyze the effect of ball diameter. It is shown that the strain increases from 0.0025 to 0.0052, while the crystalline size decreases to 18 nm. تفاصيل المقالة -
حرية الوصول المقاله
5 - Theoretical analysis and intensity calculation for the f → d absorption spectrum of Ce3+ in YAl3(BO3)4 crystal
Imen Kebaïli Mohamed DammakAbstractEmission, absorption, and excitation spectra of 4f → 5d transitions of Ce3+ ions in yttrium aluminum borate (YAB) crystal are reviewed and successfully reproduced by theoretical investigations. The Ce3+ energy level diagram has been compiled after a careful anal أکثرAbstractEmission, absorption, and excitation spectra of 4f → 5d transitions of Ce3+ ions in yttrium aluminum borate (YAB) crystal are reviewed and successfully reproduced by theoretical investigations. The Ce3+ energy level diagram has been compiled after a careful analysis of the optical spectra. Theoretical calculations based on free ion and crystal field Hamiltonians are used to interpret the observed transitions. The 4f and 5d crystal field parameter permits determination of the engine states of Ce3+ ion in YAB and then calculating the absorption line intensities as well as the effective section and the decay times. تفاصيل المقالة -
حرية الوصول المقاله
6 - Gradient effects on dust lattice waves in paramagnetic dusty plasma crystals
Mehran ShahmansouriAbstractDust lattice modes are studied in a hexagonal two-dimensional lattice in plasma crystal, including paramagnetic dust particles. The gradients of magnetic fields, electric fields, and dust charge and also the interaction of dipole-dipole take into account. These أکثرAbstractDust lattice modes are studied in a hexagonal two-dimensional lattice in plasma crystal, including paramagnetic dust particles. The gradients of magnetic fields, electric fields, and dust charge and also the interaction of dipole-dipole take into account. These gradients modify the levitation condition and affect the frequencies of dust lattice waves. The coupling between in-plane and out-of-plane modes gives rise to the hybrid mode, which is always an unstable mode. However, intersection of the in-plane mode with other modes does not result in mode-coupling instability. تفاصيل المقالة -
حرية الوصول المقاله
7 - Williamson-Hall analysis in estimation of lattice strain in nanometer-sized ZnO particles
VD Mote Y Purushotham BN DoleAbstractZnO nanoparticles were prepared by coprecipitation method at 450C. X-ray diffraction result indicates that the sample is having a crystalline wurtzite phase. Transmission electron microscopy (TEM) result reveals that the ZnO sample is spherical in shape with an أکثرAbstractZnO nanoparticles were prepared by coprecipitation method at 450C. X-ray diffraction result indicates that the sample is having a crystalline wurtzite phase. Transmission electron microscopy (TEM) result reveals that the ZnO sample is spherical in shape with an average grain size of about 50nm. X-ray peak broadening analysis was used to evaluate the crystalline sizes and lattice strain by the Williamson-Hall (W-H) analysis. All other relevant physical parameters such as strain, stress, and energy density values were also calculated using W-H analysis with different models, viz, uniform deformation model, uniform deformation stress model and uniform deformation energy density model. The root mean square strain was determined from the interplanar spacing and strain estimated from the three models. The three models yield different strain values; it may be due to the anisotropic nature of the material. The mean particle size of ZnO nanoparticles estimated from TEM analysis, Scherrers formula and W-H analysis is highly intercorrelated. تفاصيل المقالة -
حرية الوصول المقاله
8 - Temperature dependence dielectric behavior of Ge-doped lead scandium tantalate single crystals
Chandra Kumar Dixit Anil Kumar SrivastavaAbstractThe doping of Pb2SeTaO6 with Ge ferroelectrics was produced by a high-temperature solution method. We measure dielectric constant, dielectric loss and conductivity in the temperature range −30°C to 200°C and frequency range 1 to 100 KHz. The value of dielectric أکثرAbstractThe doping of Pb2SeTaO6 with Ge ferroelectrics was produced by a high-temperature solution method. We measure dielectric constant, dielectric loss and conductivity in the temperature range −30°C to 200°C and frequency range 1 to 100 KHz. The value of dielectric constant of the Pb2SeTaO6 (PST) crystal remained the same after thermal annealing whereas they decreased after Ge doping in the phase transition temperature range of the PST single crystal. All samples were investigated for conductivity with increasing temperature. تفاصيل المقالة -
حرية الوصول المقاله
9 - Electrical conduction in nanoceramic PGT synthesised by high energy ball milling
SKS Parashar Satyendra Narayan Singh Mahmood Ghoranneviss Swarat ChaudhuriAbstractNanocrystalline Pb1–3x/2GdxTiO3 (where x = 0.01) abbreviated as PGT has been synthesised by high energy ball milling at room temperature. X-ray analysis shows that single-phase tetragonal structure of nanocrystalline PGT was formed after 15-h milling. The averag أکثرAbstractNanocrystalline Pb1–3x/2GdxTiO3 (where x = 0.01) abbreviated as PGT has been synthesised by high energy ball milling at room temperature. X-ray analysis shows that single-phase tetragonal structure of nanocrystalline PGT was formed after 15-h milling. The average crystallite size was found to be 17 nm. The frequency-dependent AC conductivity of the PGT ceramic was studied in the range 100°C to 525°C. Complex impedance analysis suggested the dielectric relaxation to be of non-Debye type. The activation energy was found to be 1.04 ev. The mechanism of charge transport in nanocrystalline PGT was successfully explained by correlated hopping model. تفاصيل المقالة -
حرية الوصول المقاله
10 - One-dimensional Fibonacci fractal photonic crystals and their optical characteristics
Mehdi Tavakoli Yousef Seyed JaliliAbstractFibonacci fractal structures have been already studied. However, more special fractal structures could be beneficial in specific applications. In this paper, we create three variations of Fibonacci fractal photonic crystals as well as original structure, includi أکثرAbstractFibonacci fractal structures have been already studied. However, more special fractal structures could be beneficial in specific applications. In this paper, we create three variations of Fibonacci fractal photonic crystals as well as original structure, including: inverse Fibonacci fractal photonic crystal, mirror symmetry Fibonacci fractal photonic crystal (MSFFPC), and finally folded Fibonacci fractal photonic crystal. The transmission spectra of these structures are simulated and analyzed. Our findings show that presented structures have their own characteristics, therefore, can be used for different applications according to required specifications. Some MSFFPC structures, for instance, could be used to develop resonant microcavities with high Q factor that can be applicable in design and construction of ultrasensitive optical sensors with very high quality factor requirements. The narrower resonance peaks and the smaller amount of interfaces lead to a higher sensitivity for this structure. تفاصيل المقالة -
حرية الوصول المقاله
11 - Structural, electrical, and decorative properties of sputtered zirconium thin films during post-annealing process
Kaykhosrow Khojier Hadi Savaloni Fatemeh JafariAbstractZirconium thin films were deposited on a glass substrate using direct current magnetron sputtering technique and then post-annealed at different temperatures (100°C to 500°C in steps of 100°C) in an oxygen constant flow. The dependence of crystallographic struct أکثرAbstractZirconium thin films were deposited on a glass substrate using direct current magnetron sputtering technique and then post-annealed at different temperatures (100°C to 500°C in steps of 100°C) in an oxygen constant flow. The dependence of crystallographic structure, surface morphology, chemical composition, and electrical and decorative properties of the films on the annealing temperature was investigated. X-ray diffraction showed different phases of zirconium oxide at different annealing temperatures. It is observed that crystallite size and nanostrain increase with annealing temperature. Atomic force microscopy results showed granular structure in all samples, while both grain size and film surface roughness increased with the annealing temperature. Energy dispersive X-ray analysis data showed that the ratio of O/Zr was approximately 1.6, 1.7, 1.9, 2.1, and 2.2 at annealing temperatures of 100°C, 200°C, 300°C, 400°C, and 500°C, respectively. The annealed films at higher temperatures (400°C and 500°C) were transparent, while annealed films at lower temperatures (100°C to 300°C) were grey and brown, respectively. The variation of electrical resistance of samples with applied voltage was approximately constant, while it increased with annealing temperature. تفاصيل المقالة -
حرية الوصول المقاله
12 - Nanoscale effects on multichannel add/drop filter based on 2-D photonic crystal ring-resonator heterostructure
Hamed Pezeshki Vahid AhmadiAbstractIn this paper, we propose a heterostructure multichannel add/drop filter based on 2-D photonic crystal ring-resonator in which, add and drop operations are accomplished by coupling between two W1 waveguides. The wavelength spacing of 10.3 nm, as well as the aver أکثرAbstractIn this paper, we propose a heterostructure multichannel add/drop filter based on 2-D photonic crystal ring-resonator in which, add and drop operations are accomplished by coupling between two W1 waveguides. The wavelength spacing of 10.3 nm, as well as the average cross-talk of −37.5 dB, are the other features of the proposed filter. Furthermore, nanoscale effects on the filter's performance including wavelength spacing, cross-talk amount, and dynamic response are considered. By taking into account these effects, the minimum wavelength spacing of 12 nm is obtained, whereas the filter’s cross-talk has an average of −40 dB. Simulations are performed using 2-D finite-difference time-domain calculations. تفاصيل المقالة -
حرية الوصول المقاله
13 - Structural and optical properties of nanocrystalline α-MoO3 thin films prepared at different annealing temperatures
A. Hojabri F. Hajakbari A. Emami MeibodiAbstractNanocrystalline α-MoO3 thin films were prepared successfully by thermal annealing of molybdenum (Mo) thin films deposited on quartz and silicon substrates using DC magnetron sputtering method. The influence of annealing temperatures ranging from 400 to 1,000 °C أکثرAbstractNanocrystalline α-MoO3 thin films were prepared successfully by thermal annealing of molybdenum (Mo) thin films deposited on quartz and silicon substrates using DC magnetron sputtering method. The influence of annealing temperatures ranging from 400 to 1,000 °C on the structural, morphological and optical properties of the prepared films was investigated by X-ray diffraction, Fourier transform infrared spectrophotometer (FTIR) atomic force microscopic and UV–vis spectroscopy, respectively. The results show that the crystallinity and surface morphology of the films are strongly dependent on the annealing temperature. Also, the optimum annealing temperature of Mo films in our experiment was 600 °C and the films formed at this temperature exhibit only the (0k0) reflections and indicated the layered structure of α-MoO3. The FTIR spectra confirm the formation of MoO3. The transmittance of the MoO3 films on quartz substrate was improved with increasing annealing temperature. تفاصيل المقالة -
حرية الوصول المقاله
14 - Employing constant photocurrent method for the study of defects in silicon thin films
Hitendra K. Malik Sucheta Juneja Sushil KumarAbstractDifferent optical characterization techniques have been performed on a series of microcrystalline silicon thin films deposited using very high-frequency-assisted plasma-enhanced chemical vapor deposition process. The constant photocurrent method has been employe أکثرAbstractDifferent optical characterization techniques have been performed on a series of microcrystalline silicon thin films deposited using very high-frequency-assisted plasma-enhanced chemical vapor deposition process. The constant photocurrent method has been employed to study the defects states in density of states spectra of hydrogenated microcrystalline silicon thin films. The photocurrent measurements demonstrate anisotropy in the optoelectronic properties of the material. We have analyzed the optical absorption coefficient from UV spectroscopy and with the help of constant photocurrent method. The spectra have been analyzed in broad region and are presented for both the cases, i.e., surface and bulk light scatterings. The spectra were interpreted in terms of disorder, resulting defect density, crystalline/amorphous volume fractions and material morphology. The subgap-related parameters such as absorption coefficient, characteristic energy E0 of tail states and density of subgap defect states together with an estimate of the bandgap of silicon films prepared at various crystalline fractions have also been estimated. The density of localized tail states is found to fall exponentially toward the gap with band tail width of about 110 meV. تفاصيل المقالة -
حرية الوصول المقاله
15 - Thermal and electro-optic properties of graphene oxide-doped hexylcyanobiphenyl liquid crystal
Şükrü Özgan Hasan Eskalen Yusuf TapkıranlıAbstractHexylcyanobiphenyl liquid crystal was doped with graphene oxide at ratios %0.25GO, %0.5GO, %1GO and %2GO, and the change in physical properties of pristine and the doped liquid crystals has been investigated. The phase transitions of prepared samples were studie أکثرAbstractHexylcyanobiphenyl liquid crystal was doped with graphene oxide at ratios %0.25GO, %0.5GO, %1GO and %2GO, and the change in physical properties of pristine and the doped liquid crystals has been investigated. The phase transitions of prepared samples were studied by differential scanning calorimeter and polarized optical microscopy. The differential scanning calorimeter and polarized optical microscopy results are in good agreement when examining the nematic–isotropic liquid phase transition temperatures of the hexylcyanobiphenyl. The liquid crystal texture images obtained with polarized optical microscopy reveals that thermal stability of sample changed with graphene oxide concentration, i.e., increased with graphene oxide concentration. Impedance, capacitance, conductivity and real and imaginary dielectric constants of the pure and doped liquid crystals were obtained depending on frequency and voltage at the room temperature by using impedance analyzer. These electrical properties of the pure and the graphene oxide-doped samples showed an increase with increasing the graphene oxide ratio. The voltage-dependent light transmittance experiment revealed that threshold voltage of LC cells decreased for %0.25GO- and % 1GO-dispersed samples, but it was increased at %0.5GO- and %2GO-dispersed samples. تفاصيل المقالة -
حرية الوصول المقاله
16 - Very compact photonic crystal resonant cavity for all optical filtering
Hamed Seif-Dargahi Mahdi Zavvari Hamed Alipour-BanaeiAbstractIn this paper, an all-optical filter is proposed which employs a resonant cavity localized between input and output waveguides as wavelength selecting part of the filter. We study the impact of different parameters on the filtering of the structure using plane w أکثرAbstractIn this paper, an all-optical filter is proposed which employs a resonant cavity localized between input and output waveguides as wavelength selecting part of the filter. We study the impact of different parameters on the filtering of the structure using plane wave expansion and finite difference time domain methods. We also study the effect of the output waveguide position on the performance of the filter and results show that the proper position of the output waveguide is straight to the center of the resonant cavity. The initial form of filter is capable of selecting the optical waves at λ = 1,554.2 nm and the transmission efficiency of the filter is obtained about 100 %. The total footprint of the filter is تفاصيل المقالة -
حرية الوصول المقاله
17 - Effect of ion trapping behavior of TiO2 nanoparticles on different parameters of weakly polar nematic liquid crystal
Geeta Yadav Rohit Katiyar Govind Pathak Rajiv ManoharAbstractIn the present investigation, TiO2-doped weakly polar nematic liquid crystal (NLC) has been studied. This study mainly focuses on dielectric, electro-optical and optical properties of pure NLC and doped systems. Variation in different parameters like dielectric أکثرAbstractIn the present investigation, TiO2-doped weakly polar nematic liquid crystal (NLC) has been studied. This study mainly focuses on dielectric, electro-optical and optical properties of pure NLC and doped systems. Variation in different parameters like dielectric permittivity, dielectric loss, dielectric anisotropy and conductivity has been noticed. Permittivity of the doped system is almost the same as undoped system. With doping concentration, the ionic contribution to the dielectric loss as observed in low-frequency region has been suppressed and the shift in relaxation frequency toward higher frequency side has also been observed. The electrical conductivity and threshold voltage have been decreased with increasing concentration of nanoparticles (NPs). The continuous increase in dielectric anisotropy with increasing the concentration of NPs has also been observed. These results have been attributed to the trapping capability of free ions by TiO2 NPs. Further, we focused on the study of photoluminescence (PL), UV absorbance and Fourier transformed infrared spectroscopy (FTIR) of pure and doped systems. The continuous increase in PL intensity without any shift in emission peak has been observed for doped systems. Enhancement in UV absorbance with increasing concentration of NPs has also been observed. The effect of NPs doping on molecular dynamics of NLC can be clearly seen by FTIR study. The results suggest that the TiO2 NP-doped weakly polar NLC can have significant improved dielectric, electro-optical and optical properties. This makes the weakly polar NLC to be a potential candidate for many applications. تفاصيل المقالة -
حرية الوصول المقاله
18 - Silver nanoparticles dispersed in nematic liquid crystal: an impact on dielectric and electro-optical parameters
Rohit Katiyar Kaushlendra Agrahari Govind Pathak Tripti Vimal Geeta Yadav Kamal Kumar Pandey Abhishek Kumar Misra Atul Srivastava Rajiv ManoharAbstractIn the present study, nematic liquid crystal (NLC) 4′-(Octyloxy)-4-biphenylcarbonitrile dispersed with three different concentrations of silver nanoparticles (Ag NPs) is characterized by electro-optical and dielectric spectroscopy method. The dispersion of Ag NP أکثرAbstractIn the present study, nematic liquid crystal (NLC) 4′-(Octyloxy)-4-biphenylcarbonitrile dispersed with three different concentrations of silver nanoparticles (Ag NPs) is characterized by electro-optical and dielectric spectroscopy method. The dispersion of Ag NPs into NLC material leads to the change in physical parameters such as dielectric permittivity, photoluminescence, threshold voltage, response time and splay elastic constant. The AC conductivity and threshold voltage of Ag NPs-dispersed composite system have increased significantly. The increase in the AC conductivity for the composite system is attributed to the Ag NPs-assisted induced charge transfer mechanism in the system. Moreover, the increase in AC conductivity value for Ag NPs/NLC composite system discloses its importance in photovoltaic solar cell. تفاصيل المقالة -
حرية الوصول المقاله
19 - Microstrain and lattice disorder in nanocrystalline titanium dioxide prepared by chemical route and its relation with phase transformation
Apurba Kanti Deb Partha ChatterjeeAbstractThe microstructure of nanocrystalline titanium dioxide (TiO2), synthesized by chemical route, is studied from X-ray peak profile analysis and transmission electron microscopy. The broadening of the X-ray diffraction peaks indicates the presence of small crystall أکثرAbstractThe microstructure of nanocrystalline titanium dioxide (TiO2), synthesized by chemical route, is studied from X-ray peak profile analysis and transmission electron microscopy. The broadening of the X-ray diffraction peaks indicates the presence of small crystallites with a significant amount of disorder. The progression of broadening at lower annealing temperatures, suggests the decrease in the strain broadening. The nano-TiO2 was found to transform partially to rutile phase from its nanocrystalline anatase phase when annealed at a temperature of 750 °C. No further appreciable change was observed after annealing at higher temperature. The lattice parameters of the anatase phase change non-linearly with temperature. It was found that there is a discontinuous change in the value of crystallite size, microstrain and thermal parameter values accompanying with the phase transformation. The microstrain associated with the nanocrystalline grain is closely associated with thermal disorder and oxygen z-displacement. The value of thermal parameter reveals a significant deviation of the Ti atom from the regular lattice sites. The present study reveals that nanocrystalline anatase TiO2 prepared by chemical route shows significant static disorder, which decreases with the increase in the annealing temperature along with concomitant phase transformation. تفاصيل المقالة -
حرية الوصول المقاله
20 - Temperature sensor utilizing a ternary photonic crystal with a polymer layer sandwiched between Si and SiO2 layers
Dena M. El-Amassi Sofyan A. Taya Dhasarathan VigneswaranAbstractRecently, one-dimensional periodic ternary photonic crystals have shown outstanding properties when compared to one-dimensional periodic binary photonic crystals. In this work, a ternary photonic crystal is proposed as a temperature sensor. The structure of the أکثرAbstractRecently, one-dimensional periodic ternary photonic crystals have shown outstanding properties when compared to one-dimensional periodic binary photonic crystals. In this work, a ternary photonic crystal is proposed as a temperature sensor. The structure of the ternary photonic structure is considered Si/polymer/SiO2. The transmission spectra of the proposed ternary photonic structure are studied for different temperatures. It is observed that as the temperature increases, the transmission peak shifts toward higher wavelengths due to thermo-optic and thermal expansion coefficients of the polymer. It is found that the temperature-sensitive transmission peak shift is considerably enhanced due to the insertion of the polymer layer between Si and SiO2 to constitute a ternary photonic crystal. تفاصيل المقالة -
حرية الوصول المقاله
21 - Temperature dependence of EXAFS spectra of BCC crystals analyzed based on classical anharmonic correlated Einstein model
Tong Sy TienAbstractIn this work, the temperature dependence of extended X-ray absorption fine structure (EXAFS) of the body-centered cubic crystals was investigated based on the anharmonic correlated Einstein model using the classical statistical theory. The oscillation of the anh أکثرAbstractIn this work, the temperature dependence of extended X-ray absorption fine structure (EXAFS) of the body-centered cubic crystals was investigated based on the anharmonic correlated Einstein model using the classical statistical theory. The oscillation of the anharmonic EXAFS spectra presented in terms of the cumulant expansion up to the fourth order. Here, the thermodynamic parameters of a system are derived from an anharmonic effective potential that has taken into account the influence of all nearest neighbors of absorbing and backscattering atoms. Analytical expressions of the first four EXAFS cumulants are obtained in simple forms of temperature or parallel mean-square relative displacement. The numerical results for crystalline molybdenum in the temperature range from 0 to 900 K are found to be in good agreement with those obtained using the other theoretical methods and experiments at various temperatures. The analytical results for the contributions of the cumulants to the amplitude reduction and phase shift of the EXAFS oscillation discover the role and meaning of high-order cumulants in analyzing the temperature dependence of the EXAFS spectra. تفاصيل المقالة -
حرية الوصول المقاله
22 - Effect of plasma oxidation parameters on physical properties of nanocrystalline nickel oxide thin films grown by two-step method: DC sputtering and plasma oxidation
F. Hajakbari S. Rashvand A. HojabriAbstractNanocrystalline nickel oxide (NiO) thin films were successfully grown on quartz substrates by two-step method. In the first step, nickel films were deposited on quartz substrates by DC magnetron sputtering technique. Then, the plasma oxidation of nickel films wa أکثرAbstractNanocrystalline nickel oxide (NiO) thin films were successfully grown on quartz substrates by two-step method. In the first step, nickel films were deposited on quartz substrates by DC magnetron sputtering technique. Then, the plasma oxidation of nickel films was used for preparation of nickel oxide. The effect of DC plasma power and treatment time on the structural, morphological and optical properties of the NiO films were investigated by different analyses. XRD results indicated that the plasma powers effectively influenced the structure of films, and the best crystallinity was obtained for plasma power of 15 w and treatment time of 20 min. The XPS, RBS and EDS analysis confirmed the presence of Ni and O elements. The FESEM and AFM images showed a granular structure with spherical shapes of grains. The optical band gap of the films synthesized under different plasma oxidation conditions was also discussed. تفاصيل المقالة -
حرية الوصول المقاله
23 - Active edible films and coatings with enhanced properties using nanoemulsion and nanocrystals
Fatemeh Kalateh Seifari Hamed AhariEnvironmental concerns related to using plastics for food packaging and consumers' demand for the extended shelf life of foods conducted the researches to develop new strategies for food packaging. The shelf life of food systems is related to the existence and growth of أکثرEnvironmental concerns related to using plastics for food packaging and consumers' demand for the extended shelf life of foods conducted the researches to develop new strategies for food packaging. The shelf life of food systems is related to the existence and growth of food pathogenic and spoilage microorganisms during food storage. Also, the environmentally friendly aspects of edible films and coatings make them appropriate substitutes for plastics in food packaging systems. Therefore, edible films and coatings which contain a food preservative introduced as hopeful novel systems for extending shelf life and preserving the quality of foods. The antimicrobial agents could be used in edible films and coating for restriction or stopping the microbial growth for prolonging the shelf life of foods. Due to the weak barrier and mechanical characteristics of most edible films and coatings, natural nanocrystals could be employed to improve the properties of them. In this review, the nanoemulsion encapsulation introduced as a technique for improving antimicrobial properties, while minimizing the antimicrobial agent impacts on the foods' organoleptic properties. Also, using natural nanocrystals proposed as a reinforcing agent for edible packaging material. The shelf life of food systems is related to the existence and growth of food pathogenic and spoilage microorganisms during food storage. تفاصيل المقالة -
حرية الوصول المقاله
24 - Ultrasonic Assisted Adsorption of Crystal Violet (CV) Dye by CM-β-CD-Fe3O4NPs Synthesis: Experimental Design Methodology
Ali Omaniziarati Gholamhossein VatankhahThe applicability of the synthesized CM-β-CD-Fe3O4NPs as a novel adsorbent for eliminating Crystal Violet (CV) dye from aqueous media was investigated. This paper focuses on the development of an effective methodology to obtain the optimum removal conditions assist أکثرThe applicability of the synthesized CM-β-CD-Fe3O4NPs as a novel adsorbent for eliminating Crystal Violet (CV) dye from aqueous media was investigated. This paper focuses on the development of an effective methodology to obtain the optimum removal conditions assisted by ultrasonic to maximize removal of (CV) dye onto CM-β-CD-Fe3O4NPs in aqueous solution using response surface methodology (RSM). This novel material was characterized by different techniques such as FT-IR, XRD and SEM. The influences of variables such as initial (CV) dye concentration (X1), pH (X2), adsorbent dosage (X3), sonication time (X4) investigated by central composite design (CCD) under response surface methodology. The process was empirically modeled to reveal the significant variables and their possible interactions. The optimization conditions were set as: 10.0 mg L-1, 6.0, 5 min and 0.025 g, for ultrasound time, pH, adsorbent mass, (CV) dye concentration respectively. Finally, it was shown that the adsorption of (CV) dye removal by adsorbent was at pH 6.0. This issue that the sorption of (CV) dye conforms to the pseudo-second-order rate equation and the Langmuir model explains equilibrium data was clearly proven. The maximum monolayer capacity (qmax) was found to be 100.0 mgg-1 for (CV) dye at optimum conditions. The application of Isotherms in obtaining the thermodynamic parameters like free energy (ΔG0), enthalpy (ΔH0) and entropy (ΔS0) of adsorption were confirmed. The exothermicity of the process was proven by negative value of (ΔGo, ΔHo and ΔSo) which showed the affinity of CM-β-CD-Fe3O4NPs synthesis for Crystal Violet (CV) dye deletion. تفاصيل المقالة -
حرية الوصول المقاله
25 - Theoretical Study of Exo-Endo Interconversion of [(R)Ca1ixTMS2]Sn
Avat (Arman) TaherpourThe 1, 3-bis(trimethyl silyl)ether of p-tert-butyl calix[4]arene, Rt-Bu)Ca1ixTMS21112, has beensynthesized and used as a dianionic ligand for "Sn". The complex of [(t-Bu)Ca1ixTMS2]Snexhibits exo and endo isomerism. The structural properties of [(Rp)Ca1ixTMS2]Sn, (Rpara= أکثرThe 1, 3-bis(trimethyl silyl)ether of p-tert-butyl calix[4]arene, Rt-Bu)Ca1ixTMS21112, has beensynthesized and used as a dianionic ligand for "Sn". The complex of [(t-Bu)Ca1ixTMS2]Snexhibits exo and endo isomerism. The structural properties of [(Rp)Ca1ixTMS2]Sn, (Rpara= H,CH3, t-Bu) and the inter conversion of exoendo isomers were investigated by using of SCF-MOPM3 method. تفاصيل المقالة -
حرية الوصول المقاله
26 - Spectrophotometric Determination of Hg2+ after Solid Phase Extraction on Microcrystalline Naphthalene
M. Reza Shishehbore Navid Nasirizadeh A. Mohammad AkhoundiMercury is quantitatively retained with 1, 5-diphenylcarbazone (DPC) on microcrystallinenaphthalene in the pH range 6.5-8.5 from a large volume of aqueous solutions of various samples.After filtration, the solid mass consisting of the mercury complex and naphthalene was أکثرMercury is quantitatively retained with 1, 5-diphenylcarbazone (DPC) on microcrystallinenaphthalene in the pH range 6.5-8.5 from a large volume of aqueous solutions of various samples.After filtration, the solid mass consisting of the mercury complex and naphthalene was dissolvedin 5.0 mL of dimethylformamide (DMF) and mercury was determined by spectrophotometricmethod at 542 nm against the reagent blank. The linear calibration range for mercury was 30-18001.tg L-1 in DMF solution with a detection limit of 20 lug L-1. The relative standard deviation foreight replicate measurements of 1.0 [ig of mercury in 5.0 mL of DMF was 2.5%. The effect ofpotential interfering ions was investigated and the proposed method was applied to thedetermination of mercury in water samples. تفاصيل المقالة -
حرية الوصول المقاله
27 - SYNTHESIS, X-RAY CRYSTAL STRUCTURE AND IR STUDY OF NEW TRINUCLEAR, BASE CARBOXSYLATE COMPLEX OF [Cu3O(OAc)6(H2O)3]Cl.CH3OH.6H2O
Massoud RafizadehThe synthesis of [Cu3O(OAc)6(H2O)3]Cl.CH3OH.6H2O is described. The X-ray crystallographic study of thecomplex revealed an isosceles triangle of copper atoms with a triply bridging oxo atom nearly in the plane of thetriangle. The coordination sphere around each metal cen أکثرThe synthesis of [Cu3O(OAc)6(H2O)3]Cl.CH3OH.6H2O is described. The X-ray crystallographic study of thecomplex revealed an isosceles triangle of copper atoms with a triply bridging oxo atom nearly in the plane of thetriangle. The coordination sphere around each metal center is close to distorted octahedral and the central{Cu3(μ3-O)} core is planar. Every two copper atoms were connected to each other, by two bridge of alkylacetate.The water molecule as a monodentate ligand is connected to every copper. Counter ion of this complexis a group that contain one atom of chlorine, one molecule of methanol and six molecule of water. Thiscompound crystallizes in the orthorhombic system, space group P21212, with four molecules per unit cell. Theunit cell dimension were a = 1359.3(1)Å, b = 2317.3(1)Å, c = 908.4(1) Å, α = 90°, β = 90°, γ = 90° and V =2861.4(4)106(pm3). The final R value is 0.0667 for 5321 measured reflections. The identification, IRinvestigation and elemental analysis data are consistent with a unit cell composed of[Cu3O(AcO)6(H2O)3]Cl.CH3OH.6H2O تفاصيل المقالة -
حرية الوصول المقاله
28 - Synthesis, Characterization, and Crystal Structure Determination of Iron(III) Hetero-ligand Complex Containing Chloride, Dimethyl sulfoxide, pyridine-2, 6-dicarboxylate and Water, [Fe(Pydc)(DMSO)(H2O)Cl]
M. RafizadehA new metal-organic compound, [Fe(Pydc)(DMSO)(H2O)Cl], (where Pydc is pyridine-2, 6-dicarboxylate and DMSO is dimethyl sulfoxide), has been synthesized and characterized by singlecrystal X-ray diffraction, TGA/DTA, IR and Raman spectroscopy. Green-yellow crystals,crysta أکثرA new metal-organic compound, [Fe(Pydc)(DMSO)(H2O)Cl], (where Pydc is pyridine-2, 6-dicarboxylate and DMSO is dimethyl sulfoxide), has been synthesized and characterized by singlecrystal X-ray diffraction, TGA/DTA, IR and Raman spectroscopy. Green-yellow crystals,crystallized in the monoclinic system, space group P21/n, a = 7.2461(4) Å, b = 10.3018(4) Å, c =17.7667(10) Å, α = 90°, β = 90.014°(5), 1329.54(12) Å3, Z = 4 and R = 0.0317. In the molecule ofthe crystallized compound Fe ion is sixfold coordinated with distorted octahedral geometry andthe structure is stabilized by O-H…O hydrogen bonds. تفاصيل المقالة -
حرية الوصول المقاله
29 - The hydrothermal synthesis and X-ray crystal structure of Ag (1)-4, 4"-bipyridine-based coordination polymer
R. Ranjineh Khojasteh F. Hosseinpouli Mamaghan S. GhelengiHydrothermal synthetic were studied for the preparation of coordination polymeric material basedon Ag (I) and 4, 4"-bipy. A polymeric compound [Ag (4, 4'-bipy)].NO3. (I), was prepared andstructurally characterized by single crystal X-ray diffraction. Compound 1(91% yiel أکثرHydrothermal synthetic were studied for the preparation of coordination polymeric material basedon Ag (I) and 4, 4"-bipy. A polymeric compound [Ag (4, 4'-bipy)].NO3. (I), was prepared andstructurally characterized by single crystal X-ray diffraction. Compound 1(91% yield) was isolatedfrom the reaction of AgNO3 with 4, 41bipy in 2:1 molar ratio. In compound I. each silver (I) islinked to two nitrogens of different but symmetry-equivalent 4, 4"-bipy units in a nearly linearcoordination to form extended chains. تفاصيل المقالة -
حرية الوصول المقاله
30 - Synthesis of Nanozeolite NaX and Optimization of the Method
S. Jalilehvand B. Amirpour R. Fazaeli M. H. Givianrad A. Mashinchian moradiIn this investigation we synthesized NaX-Nanozeolite by hydrothermal crystallization conditions.These nanoparticles were prepared at different conditions in a temperature controlled shaker. Thesynthesized zeolites were characterized by instrumental analysis methods, suc أکثرIn this investigation we synthesized NaX-Nanozeolite by hydrothermal crystallization conditions.These nanoparticles were prepared at different conditions in a temperature controlled shaker. Thesynthesized zeolites were characterized by instrumental analysis methods, such as X-raydiffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) andtransmission electron microscopy (TEM) techniques. The observed results showed particle sizebetween 20 to100 nm. Then we examined the influence of different parameters on particle sizesuch as reaction time, temperature and agitation. Crystallization with shaking at 60°C for 2 dayswas the best conditions for synthesis of NaX-Nanozeolite. تفاصيل المقالة -
حرية الوصول المقاله
31 - Investigation of Variations of Isotropic g- and A- Values with Orientation of Trapped O2−, N2− and Cl2− Radicals in KCl and NaCl Crystals
Fatih Ucun Serkan Kaya -
حرية الوصول المقاله
32 - بررسی میزان ترکیبات فنلی در انواع شکر حاصل از مراحل مختلف فرایند کریستالیزاسیون طی 2 سال نگهداری
مسعود هنرور فاطمه سید سجادی احمد کلباسی اشتری کامبیز لاریجانی بابک دلخوش پرنیان متقیانمقدمه:شکر به عنوان یک ماده غذایی پر مصرف که در تهیه بسیاری از مواد غذایی دیگر کاربرد دارد، طی فرایند طولانی و پر هزینه ای تولید میشود که با حذف مراحلی از این فرایند میتوان از دور ریز مواد مغذی، با ارزش تغذیهای بالا جلوگیری کرد.در این مطالعه، ترکیبات فنلی به عنوان یک أکثرمقدمه:شکر به عنوان یک ماده غذایی پر مصرف که در تهیه بسیاری از مواد غذایی دیگر کاربرد دارد، طی فرایند طولانی و پر هزینه ای تولید میشود که با حذف مراحلی از این فرایند میتوان از دور ریز مواد مغذی، با ارزش تغذیهای بالا جلوگیری کرد.در این مطالعه، ترکیبات فنلی به عنوان یک شاخص ارزشمند وماده غذایی عملگرا، مد نظر قرار گرفته است. مواد و روشها: در این مطالعه اثر فاکتور زمان بر نمونه های شکر از طریق آزمونهای تعیین میزان تغییرات ترکیبات فنلی با استفاده از روش Singleton، تغییرات شیمیایی (میزان قند،میزان اینورت،رنگ،میزان خاکستر، pH) و آزمون های میکروبی با استفاده از روشهای استاندارد بین المللی ICUMSA اندازه گیری شده است. یافتهها:نتایج آزمونهای میکروبی آلودگی باکتریایی مزوفیل را نشان میدهد. نتایج آزمون های شیمیایی نشان میدهد که با گذشت زمان در شکر بدون کلرساژ، شکر پخت ІІ و شکر پخت ІІІ میزان قند، اینورت و رنگ کاهش یافته و در میزان ترکیبات فنلی افزایش قابل توجهی مشاهده می شود. که در این رابطه بین نمونه ها تفاوت آماری معنیدار مشاهده می گردد. نتیجهگیری: با توجه به نتایج حاصله، با ایجاد شرایط کنترل شده، میتوان شکرهایی را تولید کرد که علاوه بر جلوگیری از پدیده حذف مواد مغذی در زمان تولید منجر به حفظ و بعضاَ افزایش ارزش کیفی، در طی نگهداری شود تفاصيل المقالة -
حرية الوصول المقاله
33 - تولید فیلم نانوکامپوزیتی تهیه شده از صمغ دانه به/ نانو کریستال سلولز و بررسی ویژگیهای فیلم ترکیبی حاصل
طاهره بیضاوی سارا انصاری نرجس دانشمقدمه: امروزه برای بهبود خصوصیات فیلم های خوراکی از روش های مختلفی استفاده می شود که یکی از موثرترین و رایج ترین اینروش ها، استفاده از پرکننده ها در مقیاس نانومتری و تولید نانوکامپوزیت های پلیمری می باشد. هدف از تحقیق حاضر تولید فیلم ترکیبی تهیهشده از صمغ دانه به و نانو أکثرمقدمه: امروزه برای بهبود خصوصیات فیلم های خوراکی از روش های مختلفی استفاده می شود که یکی از موثرترین و رایج ترین اینروش ها، استفاده از پرکننده ها در مقیاس نانومتری و تولید نانوکامپوزیت های پلیمری می باشد. هدف از تحقیق حاضر تولید فیلم ترکیبی تهیهشده از صمغ دانه به و نانوکریستال سلولز و بررسی ویژگی های مختلف فیلم ترکیبی حاصل می باشد. مواد و روشها: در مرحله اول موسیلاژ دانه به استخراج و سپس به همراه درصدهای مختلف از نانوکریستال سلولز (3 ، 5 و 7 درصد) و 35%گلیسرول به عنوان پلاستیسایزر برای تولید فیلم نانوکامپوزیتی به روش قالبگیری مورد استفاده قرار گرفت. سپس خصوصیات فیزیکی،مکانیکی، ممانعت کنندگی، حرارتی و ساختاری فیلم ها مورد بررسی قرار گرفتند.یافته ها: نتایج نشان داد که افزودن نانوکریستال ها موجب افزایش ضخامت فیلم های تولیدی گردید، درحالی که میزان رطوبت، حلالیت ونفوذپذیری به بخار آب فیلم های نانوکامپوزیتی صمغ دانه به با افزایش غلظت نانوکریستال سلولز تا 7% بترتیب به میزان 7.2 ، 29.3 و 5.6 درصدکاهش یافت. افزایش غلظت نانوکریستال همچنین باعث افزایش پارامترهای رنگی a* و b* و کاهش فاکتور L* گردید. با افزودننانوکریستال سلولز میزان مقاومت کششی و مدول یانگ فیلم های نانوکامپوزیتی بطور معنی داری افزایش یافت، درحالی که افزایش درصدافزایش طول معنی دار نبود. دمای انتقال شیشه ای فیلم ها نیز در اثر افزودن نانوکریستال های سلولز افزایش یافت که این موضوع با روشگرماسنجی روبشی افتراقی تعیین گردید. برهمکنش مولکولی میان نانوکریستال های سلولز و صمغ دانه به نیز توسط طیف سنجی مادونقرمز تبدیل فوریه ( FT-IR ) تایید گردید.نتیجه گیری: نانوکامپوزیت های تولیدی در مطالعه حاضر به دلیل خصوصیات فیزیکی مناسب، نفوذپذیری کم به بخار آب و ویژگی هایمکانیکی مطلوب، قابلیت استفاده در کاربردهای بسته بندی را به خوبی دارا می باشند. تفاصيل المقالة -
حرية الوصول المقاله
34 - بررسی کمی و کیفی تولید نانو بلور سلولز از پسماندهای نخل خرما (Phoenix Dactylifera L.) به روش هیدروليز
علی خضیری حسن ذکی دیزجی محمد رضا فتحی عمادآبادیزمینه و هدف: سلولز موجود در ضایعات و زائدات بخش کشاورزی، میتواند منبع مناسبی برای تولید مواد باارزش بر پایه سلولز در صنعت باشد. سلولز و نانو کریستال سلولز توسط فرآیندهای مختلف از منابع گیاهی مختلفی استخراج و تولید میشود. هدف این پژوهش بررسی شرایط هیدرولیز اسیدی بر ساخ أکثرزمینه و هدف: سلولز موجود در ضایعات و زائدات بخش کشاورزی، میتواند منبع مناسبی برای تولید مواد باارزش بر پایه سلولز در صنعت باشد. سلولز و نانو کریستال سلولز توسط فرآیندهای مختلف از منابع گیاهی مختلفی استخراج و تولید میشود. هدف این پژوهش بررسی شرایط هیدرولیز اسیدی بر ساختار نانو بلورهای سلولزی تولید شده از زائدات هرس نخل خرما می باشد. روش بررسی: در این تحقیق ابتدا سلولز از مواد زائد حاصل از هرس برگ نخل خرما استخراج و سپس توسط روش هیدرولیز اسیدی، سلولز استخراجی به نانوبلور سلولز تبدیل شد. سپس تأثیر دو پارامتر دما (در سه سطح 30، 45 و 60 درجه سلسیوس) و زمان (در سه سطح 45 ، 60 و 120 دقیقه) بر کیفیت و کمیت نانو بلورهای حاصل از برگ درخت خرما گونه استعمران موردمطالعه قرار گرفت. برای تحلیل ویژگیهای کیفی و کمی نمونهها از روشهای طیف سنجی فروسرخ (FTIR)، آزمون پراش اشعه ایکس(XRD)، میکروسکوپ الکترونی روبشی(SEM) و دستگاه اندازهگیری ذرات(PSA) استفاده شد. یافتهها: نتایج استخراج سلولز از برگ درخت نخل نشان داد، افزایش دما در مرحله لیگنین زدایی و رنگ بری باعث افزایش خلوص سلولز استخراجی میشود. همچنین تیمارهای شدیدتر باعث ایجادنانو بلورهایی با ابعاد کوچکتر (5 تا 100 نانومتر بوده و عمدتا 30 نانومتر) میشود. در این پژوهش زمان 60 دقیقه و دمای 60 درجه سلسیوس بهعنوان بهترین فاکتورها از میان فاکتورهای مشابه معرفی گردید که در این تیمار 50% ذرات دارای میانگین قطری 37/1 نانومتر میباشند. بحث و نتیجه گیری: نتیجه بررسی نشان داد اگر نانو بلورهای سلولزی استخراجی به صورت شبکهای تبدیل شوند پتانسیل کاربرد در نانو فیلترها و نانو داربستهارا دارا می باشند. تفاصيل المقالة -
حرية الوصول المقاله
35 - بررسی عملکرد ایمنی درصنعبررسی عملکرد ایمنی درصنعت شیشه و بلور و ارایه راهکارهای مدیریت بهبود (مطالعه موردی: عملکرد کارخانه شیشه و بلور اصفهان به عنوان بزرگترین کارخانه تولید شیشه و بلورکشور
تورج دانا فاطمه پهلوانی نژادزمینه و هدف: سالیانه در جهان میلیون ها کارگر قربانی حوادث ناشی از کار می شوند. بر اساس گزارش سازمان بین المللی کار، 120میلیون حادثه در سال اتفاق می افتد که منجر به فوت و یا از کار افتادگی تعداد زیادی از نیروی انسانی کاری می گردد. درکشورهای پیشرفته صنعتی سالانه از هر ده أکثرزمینه و هدف: سالیانه در جهان میلیون ها کارگر قربانی حوادث ناشی از کار می شوند. بر اساس گزارش سازمان بین المللی کار، 120میلیون حادثه در سال اتفاق می افتد که منجر به فوت و یا از کار افتادگی تعداد زیادی از نیروی انسانی کاری می گردد. درکشورهای پیشرفته صنعتی سالانه از هر ده نفر کارگر یکی دچار سانحه شده و در نتیجه این گونه حوادث، پنج درصد روزهای کار ملی به هدر می رود. حوادث و بیماری های ناشی از کار، هزینه های زیادی را بر افراد، صنایع و اقتصاد ملی کشورها تحمیل می کنند که این رقم در حدود5/48 میلیارد دلار در سال تخمین زده می شود. روش بررسی: تحقیق حاضر برای اولین بار در کشور در صنعت بلور و شیشه و به صورت مطالعه موردی در کارخانه شیشه و بلور اصفهان انجام پذیرفته است. این مطالعه از طریق آمارهای مقایسه ای حوادث و رویدادها و تجزیه و تحلیل و برآورد میزان آسیب به نیروی کاری این صنعت طی بازه زمانی دوازده ساله (1380 تا1392) صورت گرفته است. درادامه با بررسی یافته های تحقیق، راهکارهای بهبود و مدیریتی از جنبه ی توسعه پایدار صنعتی ارایه گردیدند. هدف غایی از نگارش مقاله حاضر، بررسی وضعیت شاخص های عملکرد ایمنی صنعت بلور و شیشه کشور به جهت ارتقای سطح سلامت کار و ایمن بودن شرایط محیط کار می باشد. یافتهها: یافته های تحقیق نشان داد بیشترین حوادث ثبت شده در امور تولید با فراوانی نسبی 38% بوده است و رده های سنی 36 تا 40 سال در حدود 41% از حوادث (بیشترین مقدار) را به خود اختصاص داده است.از سویی نتایج پژوهش نشان می دهد که افراد با سابقه کاری بین 1 تا 5 سال ، بیشترین میزان مواجهه با حوادث را دارند. عوامل اصلی ایجاد حوادث برخورد با اشیاء ،سقوط اشیاء، گیرافتادگی و سقوط افراد بوده و مهم ترین اندام آسیب دیده دست کارکنان با فراوانی نسبی 58% بوده است. بیشترین حوادث در سال 1391 رخ داده و آموزش کارکنان سهم به سزایی در کاهش حوادث سال بعد داشته است. تفاصيل المقالة -
حرية الوصول المقاله
36 - Synthesis, Characterization and Crystal Structure Determination of Copper (II) Complexes with 2,2′-Dimethyl-4,4′-bithiazole
Farank Pirsiavash Vahid Amani Anita AbediCopper(II) complex [Cu(dmbt)2(H2O)](ClO4)2 (1) was prepared from the reaction of copper(II) perchlorate hexahydrate with 2,2'-dimethyl-4,4'-bithiazole (dmbt) ligand in methanol at ambient temperature. The complex was quantitatively and qualitatively characterized by ele أکثرCopper(II) complex [Cu(dmbt)2(H2O)](ClO4)2 (1) was prepared from the reaction of copper(II) perchlorate hexahydrate with 2,2'-dimethyl-4,4'-bithiazole (dmbt) ligand in methanol at ambient temperature. The complex was quantitatively and qualitatively characterized by elemental analysis, absorption and infrared spectrometries. Complex [Cu(DMSO)5](ClO4)2 (2) was also synthesized from the recrystallization of complex [Cu(dmbt)2(H2O)](ClO4)2 (1) in the dimethyl sulfoxide solvent through a slow evaporation of the solvent at room temperature. The compound was characterized by elemental analysis, infrared spectrometry and single-crystal X-ray diffraction. Crystallographic analysis of this complex revealed that the single crystal of this compound is crystallized in the trichlinic crystal structure, with the space group Pī and cell dimensions of a = 10.894(3), b = 10.853(4) and c = 12.947(5)Å as well as the angle β = 111.95 (3)°.Interestingly, this compound is the first example of 5-coordinated copper(II) complex with dimethyl-sulfoxide ligand in a square pyramid structure. تفاصيل المقالة -
حرية الوصول المقاله
37 - Optimization of Experimental Conditions in Single-Stage Process for Preparation of Potassium Sulphate from Magnesium Sulfate and Potassium Chloride
Elham Arshadi Babak Nahri-Niknafs Manoochehr Dastoor Seyed-Ali SobhanianA method and a system for Single-Stage conversion of magnesium sulphate and potassium chloride to potassium sulphate in aqueous alcoholic solution at 50-85°C were developed. Raw magnesium chloride was a by-product formed in the process. The effects of reaction molar أکثرA method and a system for Single-Stage conversion of magnesium sulphate and potassium chloride to potassium sulphate in aqueous alcoholic solution at 50-85°C were developed. Raw magnesium chloride was a by-product formed in the process. The effects of reaction molar ratio, methanol volume, evaporation, and magnesium chloride content on the purity and the conversion rate of potassium sulphate were studied. The product and by-product were purified and the metal ions contents were determined by Atomic absorption spectroscopy. Results showed that the washing with methanol had a certain impact on the purity and the conversion rate of potassium sulphate. The potassium sulphate reached to the qualified standard, when the molar ratio of 2KCl and MgSO4 was 1:1. The recoveries of potassium sulphate (as final product) and potassium chloride (as raw material)in an aqueous alcoholic solution compound fertilizer were approximately 80% and 12.76%, respectively. Magnesium chloride had a significant influence on the purity and the conversion rate of potassium sulphate. Purities of products throughout can be controlled by using slight circuit adjustments and/or by additional water washes. تفاصيل المقالة -
حرية الوصول المقاله
38 - Synthesis, Crystal Structure and Antibacterial Evaluation of Di-μ-chlorido-bis({2-[(4-methoxyphenyl)- iminomethyl]pyridine-κ2N,N']Mercury(II)
Behzad Jamali Aghbash Mahboubeh Manoochehri Maryam Daghighi AsliNew coordination polymer of [HgLCl2]n (1) with HgCl2 and Schiff base bidentate ligand (4-methoxyphenyl) pyridine-2yl methyleneamine (L) was prepared and structurally characterized. In the 1D network structure of 1, the mecury (II) ion adopts an HgN2Cl3 distorted square أکثرNew coordination polymer of [HgLCl2]n (1) with HgCl2 and Schiff base bidentate ligand (4-methoxyphenyl) pyridine-2yl methyleneamine (L) was prepared and structurally characterized. In the 1D network structure of 1, the mecury (II) ion adopts an HgN2Cl3 distorted square pyramid geometry. In this complex, one of the chlorine acts as bridging ligand connecting two adjacent mercury(II) ions while, the L ligand is coordinated to mercury(II)ion in a cyclic-bidentate fashion forming an five-membered metallocyclic ring. Coordination compounds1 has been characterized by infrared spectroscopy, UV-visible spectroscopy, elemental analyses and single-crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P 21/c with a = 9.3053(17), b = 7.1125(13), c = 20.708(4), and β = 80.208(4)°. The antibacterial activities of the complex, ligand and metal salt were tested against Gram-positive bacteria Staphylococcus aureus and Gramnegativebacteria Escherichia coli studied by disk diffusion method. تفاصيل المقالة -
حرية الوصول المقاله
39 - Cadmium Oxide Thin Films Deposited by a Simplified Spray Pyrolysis Technique for Optoelectronic Applications
K. Usharani A.R. Balu M. Suganya V.S. NagarethinamCadmium oxide thin films were fabricated on glass substrates by a simplified and low cost spray pyrolysis technique at different substrate temperatures. The X-ray diffraction study showed that irrespective of substrate temperature all the films exhibits a preferential أکثرCadmium oxide thin films were fabricated on glass substrates by a simplified and low cost spray pyrolysis technique at different substrate temperatures. The X-ray diffraction study showed that irrespective of substrate temperature all the films exhibits a preferential orientation along the (1 1 1) plane. The values of crystallite size were found to be in the range 20.72 – 29.6 nm. The percentage transmittance and the optical band gap values are found to be in the range of 78 – 89 % and 2.38 – 2.55 eV respectively. The optical transmittance is found to increase gradually with increase in substrate temperature. Urbach energy decreases with increase in substrate temperature. Optical parameters such as refractive index and packing density were calculated. The dispersion parameters of the as-deposited CdO films were calculated to analyze their choice in designing optical devices. PL studies confirm that the films exhibit strong luminescent properties. The value of ρ decreases with increase in substrate temperature and attains a minimum value of 0.26x 10-6 ohm-m for the film coated at 375ºC which has the least thickness. تفاصيل المقالة -
حرية الوصول المقاله
40 - Application of Magnetic-modified Fe3O Nanoparticles for Removal of Crystal Violet from Aqueous Solution: Kinetic, Equilibrium and Thermodynamic Studies
Shiva Dehghan AbkenarThe prepared magnetic-modified Fe3 O4 nanoparticles (Fe3 O4 -TAN) were used as adsorbent for removal of crystal violet (CV) from water solution. The effects of pH, contact time, dye concentration and temperature on adsorption were determined. The experimental data were أکثرThe prepared magnetic-modified Fe3 O4 nanoparticles (Fe3 O4 -TAN) were used as adsorbent for removal of crystal violet (CV) from water solution. The effects of pH, contact time, dye concentration and temperature on adsorption were determined. The experimental data were analyzed using the Langmuir adsorption model. The data fitted well to the model with maximum adsorption capacities 84.0 mg/gunder pH=11.0. Also the adsorption kinetics and thermodynamic parameters were studied and evaluated. Adsorption of the CV to nanoparticles reached equilibrium after 15 min. In addition, the external magnetic field could easily separate nanoparticles from water with high separation efficiency. تفاصيل المقالة -
حرية الوصول المقاله
41 - Optimization of Nanocrystals NaX Zeolite Synthesis with Different Silica Sources
Mansoor Anbia Farideh BandarchianThe effects of varying the silica source on synthesis of NaX zeolite crystals via conventional hydrothermal method have been investigated. Five different silica sources were selected while other parameters like Al source, reaction and aging time, SiO2/Al2O3molar ratio أکثرThe effects of varying the silica source on synthesis of NaX zeolite crystals via conventional hydrothermal method have been investigated. Five different silica sources were selected while other parameters like Al source, reaction and aging time, SiO2/Al2O3molar ratio and temperature were same. The prepared products were characterized by XRD technique. The results showed that different crystallites, different conversion rates and different amounts of impurity phase in the synthesized NaX zeolite. For more evidence the best obtained powder of NaX zeolite nanoparticles was checked by FTIR, SEM, TGA, and BET analysis. The corresponding sample had a good agreement with standard IR peaks, octahedral nanocrystals of zeolite X, thermal stability up to 800°C, surface area 751.88 m2/g and total pore Volume 0.3599 cm3/g respectively. Therefore, it can be concluded that the use of different silica sources significantly influence the synthesized products. تفاصيل المقالة -
حرية الوصول المقاله
42 - The Methods of Quasicrystals Producing
H Bakhtiari M Abaei M. R Rahimipour M Farvizi M. J EshraghiQuasicrystals are structures that are both regular and non-periodic. In quasicrystals, there is an iterative rule in the arrangement of atoms, along with abnormal rotational symmetry for crystals, that is, they form patterns that fill space but have no transfer symmetry أکثرQuasicrystals are structures that are both regular and non-periodic. In quasicrystals, there is an iterative rule in the arrangement of atoms, along with abnormal rotational symmetry for crystals, that is, they form patterns that fill space but have no transfer symmetry. These structures are generally made of alloys of aluminum, copper, nickel, magnesium, zinc, zirconium, and titanium. These materials have attracted the attention of many researchers in recent years due to their extraordinary physical and mechanical properties. Due to the extraordinary properties and different production methods, it can be expected that these materials will be used more in different industries in the near future. Therefore, it is very important to study the methods of preparation of these materials. In this article, we first introduce the quasicrystals and their outstanding properties and then examine their common production methods, which include melt spinning, mechanical alloying, coating method, sputtering, physical vapor deposition, and thermal spraying, along with their advantages and disadvantages تفاصيل المقالة -
حرية الوصول المقاله
43 - An Overview of Quasicrystals, Their Types, Preparation Methods, Properties
H Bakhtiari M. R Rahimipour M Farvizi M. R KhanzadehQuasicrystals, unlike crystals that contain regular and repetitive patterns, are composed of regular patterns that are not repetitive. Moreover, the symmetry of quasicrystals in crystals is impossible. For example, ordinary crystals can have triple symmetries from the r أکثرQuasicrystals, unlike crystals that contain regular and repetitive patterns, are composed of regular patterns that are not repetitive. Moreover, the symmetry of quasicrystals in crystals is impossible. For example, ordinary crystals can have triple symmetries from the repetition of a triangle or quadruple symmetries from the repetition of a cube. Quasicrystals are a special type of real crystals that are artificially formed only in laboratories, under certain conditions and temperatures, and it is not possible to form them like the earth. Evidence suggests that quasicrystals can form naturally under conditions contrary to astrophysical laws and remain stable for long periods. Quasicrystals are a group of new materials with unique mechanical, physical, and chemical properties. Among the known properties of these materials are low adhesion and friction, high resistance to corrosion, very high hardness, electrical insulation at low temperatures, and light absorption. Quasicrystals are used in non-stick coatings, nanoparticles, hydrogen storage, reinforcing phases in composites, catalysts, thermal insulation, infrared light absorption, and corrosion protection. In this article, we refer to some of the main topics related to quasi-crystal تفاصيل المقالة -
حرية الوصول المقاله
44 - تحلیل یک مدولاتور الکترواپتیک بر پایه کاواک نانو پرتو بلور فوتونی تکبعدی همراه با ساختار متناوب گرافن بر اکسید آلومینیوم
مظفرالدین فردوسیان طهرانی رحیم غیور مریم محیط پوردر این مقاله، ما یک مدولاتور الکترو - اپتیک بر اساس جذب گرافن ارائه میکنیم. در این ساختار، گرافن بر روی اکسید آلومینیوم قرار گرفته که ساختار به صورت متناوب تکرار میشود. این ساختار متناوب گرافن بر اکسید آلومینیوم در داخل یک حفره نیماستوانهای، درون یک کاواک نانو پرتو أکثردر این مقاله، ما یک مدولاتور الکترو - اپتیک بر اساس جذب گرافن ارائه میکنیم. در این ساختار، گرافن بر روی اکسید آلومینیوم قرار گرفته که ساختار به صورت متناوب تکرار میشود. این ساختار متناوب گرافن بر اکسید آلومینیوم در داخل یک حفره نیماستوانهای، درون یک کاواک نانو پرتو بلور فوتونی یک بعدی قرار گرفته است. برخلاف مقالات قبلی که کاواک نانو پرتو بلور فوتونی یک بعدی شامل حفرههای استوانهای بوده و نواحی مختلف با تغییر شعاع این حفرهها ایجاد میشد، در این ساختار از حفرههای نیمه استوانهای استفاده شده و با چرخش این نیماستوانهها، نواحی مختلف ساختار کاواک نانو پرتو بلور فوتونی ایجاد میشود. این نوع بلور فوتونی دارای ضریب کیفیت بالایی است. همچنین این نوع مدولاتورها پس از ساخت به فضای کمی نیاز دارند، بنابراین گزینه بسیار مناسبی برای مدارهای مجتمع هستند. در این مقاله از روش دامنه محدود در حوزه زمان - سهبعدی برای تحلیل استفاده شده است. در این مدولاتور مشاهده میشود که با تغییر ولتاژ بایاس میزان پیک جذب و همچنین طول موج رزونانس آن تغییر می‎کند. در نتیجه این تغییرات، به عمق مدولاسیونی در حدود ۷ دسیبل دست مییابیم. ساختار پیشنهادی ما میتواند کاربردهای بالقوهای در مدارهای مجتمع نوری، بهویژه در فرکانسهای مخابراتی داشته باشد. تفاصيل المقالة -
حرية الوصول المقاله
45 - بررسی آنتنهای مسطح بر روی زیرلایههای کریستال فوتونیک و دوقطبی مسطح
محبوبه بحرینیدر حالت کلی، فوتونیک کریستال ها ساختارهایی از مواد هستند که نفوذپذیری الکتریکی و مغناطیسی آن ها به طور تناوبی در یک، دو و یا سه بعد تغییر می کند. هنگامی که یک اینچنین ساختارهایی در معرض تابش یک اشعه که دارای طول موجی قابل مقایسه با دوره ی تناوب فضایی کریستال است قرار می أکثردر حالت کلی، فوتونیک کریستال ها ساختارهایی از مواد هستند که نفوذپذیری الکتریکی و مغناطیسی آن ها به طور تناوبی در یک، دو و یا سه بعد تغییر می کند. هنگامی که یک اینچنین ساختارهایی در معرض تابش یک اشعه که دارای طول موجی قابل مقایسه با دوره ی تناوب فضایی کریستال است قرار می گیرد، دو حالت رخ می دهد ، می باشددراین مقاله بررسی آنتن های مسطح بر روی زیرلایه های کریستال فوتونیک و دوقطبی مسطح بر روی زیرلایه فوتونیک کریستال پرداخته شده است. تفاصيل المقالة -
حرية الوصول المقاله
46 - شبیه سازی سنسور نوری بر اساس کوپلینگ رزونانس انتخابی
ساحل جواهرنیاسنسور های ضریب شکستی یکی از سنسورهای پرکاربرد در صنعت بیوالکترونیک و الکترونیک نوری هستند. استفاده از مواد و ساختارهایی که بتواند ضریب شکست مواد ناشناس را تشخیص دهد دارای کاربردهای مهمی در بیو شیمی و مهندسی پزشکی می باشد. در این مقاله یک نوع فیبر بلور فوتونی دو هسته ای أکثرسنسور های ضریب شکستی یکی از سنسورهای پرکاربرد در صنعت بیوالکترونیک و الکترونیک نوری هستند. استفاده از مواد و ساختارهایی که بتواند ضریب شکست مواد ناشناس را تشخیص دهد دارای کاربردهای مهمی در بیو شیمی و مهندسی پزشکی می باشد. در این مقاله یک نوع فیبر بلور فوتونی دو هسته ای برپایه پلیمر برای سنجش ضریب شکست سیال معرفی شده است. اندازه سوراخ های هسته های آنالیت و هسته جامد عبور دهنده نور به گونه ای مهندسی شده اند که توانایی عبور تک مد اصلی را داشته باشند. بدلیل ارزان بودن، توانایی مکانیکی بالا و راحتی ساخت، بستر فیبر بلور فوتونی از پلیمر PMMA استفاده شده است. پس از شبیه سازی ساختار و استفاده از روابط ریاضی موجود و بررسی مد های انتشاری، برای انتقال کامل نور از هسته جامد به هسته کانال آنالیت، طول فیبر 0.13 سانتی متر بدست آمده است. نتایج شبیه سازی نشان می دهد که برای ضریب شکست 1.44 مقدار حساسیت 1000 و حد تشخیص توسط این سنسور قابل حصول است. تمام مراحل شبیه سازی در حوزه FDTDدر نرم افزار Lumerical بدست آمده است. تفاصيل المقالة -
حرية الوصول المقاله
47 - بررسی جذب CO در نانوساختارهای کبالت با استفاده از تئوری تابعی چگالی (DFT): فازهای کریستالی مکعبی و هگزاگونال
فاطمه دولتی علی نخعی پور وحیدرضا داروگر زهره دولتی وجیهه افخمیدر این مقاله، انرژی جذب و ساختار مونوکسید کربن (CO) در فازهای کریستالی مکعبی(fcc) و هگزاگونال (hcp) در نانو ذرات کبالت با استفاده از محاسبات تابعی چگال (DFT) مورد ارزیابی قرار گرفته است. روند کلی فعالیت سنتز فیشر تروپش (FTS) بر روی کاتالیزورهای کبالت با مقایسه انرژی جذب أکثردر این مقاله، انرژی جذب و ساختار مونوکسید کربن (CO) در فازهای کریستالی مکعبی(fcc) و هگزاگونال (hcp) در نانو ذرات کبالت با استفاده از محاسبات تابعی چگال (DFT) مورد ارزیابی قرار گرفته است. روند کلی فعالیت سنتز فیشر تروپش (FTS) بر روی کاتالیزورهای کبالت با مقایسه انرژی جذب مورد بررسی قرار گرفت. با توجه به محاسبات، کاتالیزورهای کبالت در فازhcp، بازده و کارایی بهتری را نسبت به فاز فلزی fcc نشان می دهد. انرژی جذب CO در سطوح مختلف کبالت و همچنین انرژی فعال سازی جذب CO در تک لایه (1ML) در موقعیت عمودی (top) نسبت به اتم کبالت درفازهای کریستالی مکعبی و شش ضلعی نانوساختارهای کبالت محاسبه شد. نتایج نشان داد که بیشترین مقدار انرژی جذب در فازهای کریستالی fcc نسبت به hcp است. در نتیجه انرژی پایین جذب CO در موقعیت top کبالت در hcp می تواند فعالیت بالاتر این کاتالیست را نسبت به فازهای دیگر آن در واکنش FTS توضیح دهد. تفاصيل المقالة -
حرية الوصول المقاله
48 - سنتز، ساختار و انتساب های ارتعاشی کمپلکس بیس(3-آمینو- 1- فنیل-2-بوتن-1-اوناتو) نیکل(II)
مینا جامی الاحمدیبیس(3-آمینو- 1- فنیل-2-بوتن-1-اوناتو) نیکل(II)، Ni(APBO)2، سنتز شد و داده های کریستالوگرافی بهبود یافته اشعه X آن ارائه گردید. ساختار مولکولی این ترکیب با استفاده از محاسبات نظریه تابعی چگال (DFT) مورد بررسی قرار گرفت و نتایج با داده های تجربی مقایسه شد. فرکانسهای ارتع أکثربیس(3-آمینو- 1- فنیل-2-بوتن-1-اوناتو) نیکل(II)، Ni(APBO)2، سنتز شد و داده های کریستالوگرافی بهبود یافته اشعه X آن ارائه گردید. ساختار مولکولی این ترکیب با استفاده از محاسبات نظریه تابعی چگال (DFT) مورد بررسی قرار گرفت و نتایج با داده های تجربی مقایسه شد. فرکانسهای ارتعاشی هماهنگ Ni(APBO)2 در روش B3LYP با استفاده از مجموعه پایه 6-311G* بدست آمد و همه شیوههای ارتعاشی IR و Raman در این سطح محاسبه شد.. فرکانسهای ارتعاشی محاسبه شده با نتایج تجربی مقایسه شد. توافق خوبی بین فرکانسهای نظری مقیاس پذیر و پارامترهای ساختاری با داده های تجربی وجود دارد. بر اساس دادههای تجربی و محاسباتی، پیوند فلز-لیگاند در این کمپلکس، قویتر از ترکیبات Cu(APBO)2 ، Ni(APO)2 و Cu(APO)2 است. تفاصيل المقالة -
حرية الوصول المقاله
49 - Optimization of Tangential Cutting Force in Turning Operation in Machining of Unidirectional Glass Fiber Reinforced Plastics
Surinder KumarIn this paper, Taguchi method is applied to find optimum process parameters for turning UD-GFRP rods using polycrystalline diamond cutting tool. The process parameters considered include cutting speed, depth of cut, cutting environment (dry and wet) and feed rate. The e أکثرIn this paper, Taguchi method is applied to find optimum process parameters for turning UD-GFRP rods using polycrystalline diamond cutting tool. The process parameters considered include cutting speed, depth of cut, cutting environment (dry and wet) and feed rate. The experiments were conducted by L16 orthogonal array as suggested by Taguchi. Signal to Noise ratio and ANOVA are employed to analyses the effect of turning process parameter on the tangential cutting force. The results from confirmation runs indicated that the determined optimal combination of machining parameters improved the performance of the machining process. The percent contributions of cutting speed (2.46%), depth of cut (73.82%), dry and wet (3.89%) and feed rate (8.02%) in affecting the variation of tangential force are significantly larger (95 % confidence level). It has been found that the wet cutting environment reduces the tangential force. Depth of cut is the factor, which has great influence on tangential force, followed by feed rate. تفاصيل المقالة -
حرية الوصول المقاله
50 - Exploration of metabolic variations and anti-cholinesterase, anti-heme biocrystallization, and anti-protein denaturation activities of ten different Capsicum accessions under different stages of ripening
Mamita Debnath Susmita Das Jhelam ChatterjeeHydro-methanolic extracts of pericarps and seeds of 10 different Capsicum cultivars from three different species viz., Capsicum chinense, C. annuum and C. frutescens were assessed to determine metabolic variations and anti-cholinesterase, anti-malarial and anti-protein أکثرHydro-methanolic extracts of pericarps and seeds of 10 different Capsicum cultivars from three different species viz., Capsicum chinense, C. annuum and C. frutescens were assessed to determine metabolic variations and anti-cholinesterase, anti-malarial and anti-protein denaturation activities at four different stages of ripening, such as green unripe (GU), turning green-orange (TGO), orange ripe (OR) and red fully ripe (RFR) stages. Many of the ripening stages of the cultivars tested showed significant bioactivities in a dose dependent manner. Metabolites were identified using GC/MS. HPLC analysis determined the highest capsaicin and dihydrocapsaicin content in the pericarp of GU, TGO and RFR stages of C. chinense. β - carotene, capsanthin and lutein contents of C. chinense were also measured using HPTLC technique and found that the GU and RFR stages of C. chinense contained good amounts of all the three carotenoids. These results may be helpful in selecting the cultivars with the best attributes. تفاصيل المقالة -
حرية الوصول المقاله
51 - مقایسه باورهای غیرمنطقی بیماران مبتلا به اختلال سوء مصرف شیشه و افراد عادی
مریم قربانی حمید کاظمی زهرانی طاهره قربانیهدف این پژوهش مقایسۀ باورهای غیرمنطقی در مصرفکنندگان شیشه و افراد عادی بود. به همین منظور ابتدا به روش نمونهگیری در دسترس از میان مراجعهکنندگان به مرکز جامع اعصاب و روان اصفهان 36 بیمار مبتلا به سوءِ مصرف شیشه انتخاب شدند. گروه گواه شامل 36 نفر از دانشجویان و کارمن أکثرهدف این پژوهش مقایسۀ باورهای غیرمنطقی در مصرفکنندگان شیشه و افراد عادی بود. به همین منظور ابتدا به روش نمونهگیری در دسترس از میان مراجعهکنندگان به مرکز جامع اعصاب و روان اصفهان 36 بیمار مبتلا به سوءِ مصرف شیشه انتخاب شدند. گروه گواه شامل 36 نفر از دانشجویان و کارمندان دانشگاه پیام نور اصفهان نیز به روش تصادفی ساده و براساس ملاکهای سن، جنس و تحصیلات با گروه بیمار همتاسازی شدند. پس از انتخاب آزمودنیها، آزمون افکار غیرمنطقی جونز ( IBT ) در مورد هر دو گروه اجرا شد. نتایج با روش t گروههای مستقل تحلیل شد و مشخص گردید که گروه سوءِ مصرفکنندۀ شیشه نسبت به گروه گواه باورهای غیرمنطقی بیشتری دارد. همچنین نمرات گروه بیمار نسبت به گروه گواه در خردهآزمونهای نگرانی بیش از اندازه توأم با اضطراب در مورد آینده ( AO ) ، اجتناب از مشکلات ( PA ) ، وابستگی ( D ) و درماندگی نسبت به تغییر ( HC ) بیشتر بود (05/0 P < ). تفاصيل المقالة -
حرية الوصول المقاله
52 - Design of an All- Optic Communication Filter Based on Photonic Crystal Structure
Majid Malekian Hossein Emami Mohsen AshourianOne of the structures made of photonic crystal is all-optic filter which these filters are widely used in optic telecommunications systems and networks. In this paper, a method has been presented to design an optic filter based on two-dimensional photonic crystals. The أکثرOne of the structures made of photonic crystal is all-optic filter which these filters are widely used in optic telecommunications systems and networks. In this paper, a method has been presented to design an optic filter based on two-dimensional photonic crystals. The crystal which we suggested, was obtained by FDTD and PWE numeric methods, that influenced different parameters of output wavelength of filter. The result showed that increase of refraction index of Dielectric, leads information in output wavelength of filter. تفاصيل المقالة -
حرية الوصول المقاله
53 - Design and Simulation of a Waveguide Division De-multiplexer (DWDM) for Communication Application
Yadollah Shahamat Mohammad VahediWe design and simulate an efficient wavelength division demultiplexer (WDDM) based on photonic crystal without using either specific materials or complexities in the fabrication process. The photonic crystal consists of a square lattice of Chalcogenide glass with embedd أکثرWe design and simulate an efficient wavelength division demultiplexer (WDDM) based on photonic crystal without using either specific materials or complexities in the fabrication process. The photonic crystal consists of a square lattice of Chalcogenide glass with embedded in air in two dimensions. The structure involves three cavities around the boundary of the waveguide with specified distance from each other for wavelength selection. For obtaining resonant frequencies of the cavities, two dimensional Finite-Difference-Time-Domain (FDTD) simulation is used. Through simulations, characteristic resonant wavelengths of the cavities are obtained in terms of the size of the coupling rods and the inner rod of the cavity. To show the design flexibility of the proposed structure, a WDDM is designed to divide a common input containing wavelengths andinto three distinct ports with a high efficiency.. تفاصيل المقالة -
حرية الوصول المقاله
54 - Designing a New CVR Receiver and Investigating the Problem with Simultaneous Signal with Applying Approach in Electronic Warfare
Afsaneh Asgharzadeh Mohammad MirzaeiIn order to launch different receivers in electronic warfare, side-circuits are required to detect the presence of a pulse at the receiver input and to report it after making sure that the receiver output is not due to system noise alone. In practice, a crystal video re أکثرIn order to launch different receivers in electronic warfare, side-circuits are required to detect the presence of a pulse at the receiver input and to report it after making sure that the receiver output is not due to system noise alone. In practice, a crystal video receiver (CVR) is used for this purpose. This receiver provides the required time information (or domain related information) to the other part of an electronic warfare receiver by extracting the received RF signal wave envelope. In this paper, after a conceptual overview of the structure of this receiver, the analysis of its function (sensitivity) will be dealt with. Moreover, some important issues in its design will be discussed. In addition, since the IFM and CVR receivers are not capable of processing simultaneous pulses or pulses coupled with the CW, some further steps are taken to maintain system efficacy under such conditions. تفاصيل المقالة -
حرية الوصول المقاله
55 - A New Proposal for PCRR- Based Optical Channel Drop Filter
Zohreh Rashki Seyyed Javad SeyyedMahdavi ChabokRing resonators are useful elements especially in channel drop filters. A novel configuration of photonic crystal ring resonators(PCRRs) based on optical channel drop filters (CDFs) with triangular lattice is proposed. The rods of this structure is silicon with the ref أکثرRing resonators are useful elements especially in channel drop filters. A novel configuration of photonic crystal ring resonators(PCRRs) based on optical channel drop filters (CDFs) with triangular lattice is proposed. The rods of this structure is silicon with the refractive index nsi=3.46 and the surrounding environment is air with the refractive index of nair=1. The widest photonic band gap obtains for the filling ratio of r/a = 0.2. The normalized transmission spectra of CDF are observed using Two- Dimensional-finite difference time domain (2D-FDTD) method. The photonic band gap (PBG) is calculated by plane wave expansion (PWE) method. The simulation shows, 100% dropping efficiency and suitable quality factor at 1534.5nm wavelength achieved for this filter. Also in this paper, we investigate parameters which have an effect on resonant wavelength and transmission spectra in this CDF, such as refractive index of inner rods and the refractive index of whole rods of the structure. The area of the proposed structure is about 10.32μm × 10.32μm which is suitable for photonic integrated circuits and optical communication network applications. تفاصيل المقالة -
حرية الوصول المقاله
56 - High Resolution Nano Temperature Sensor Based on Two-Dimensional Photonic Crystal
Pardis Kazemi Esfeh Zahra AlaeiIn this paper, we designed a two-dimensional photonic crystal measurement nano-sensor with an octagonal ring resonator. This nano-sensor is designed using circular silicon rods in a rectangular lattice with a lattice constant of 820 nm, to detect temperatures from 0 ° C أکثرIn this paper, we designed a two-dimensional photonic crystal measurement nano-sensor with an octagonal ring resonator. This nano-sensor is designed using circular silicon rods in a rectangular lattice with a lattice constant of 820 nm, to detect temperatures from 0 ° C to 540 ° C. Photonic band gap was calculated by PWE method and the sensor operating parameters such as sensitivity, transmission efficiency, and quality factor were calculated by FDTD method. As the temperature increases, the resonance wavelength changes to a higher wavelength. The designed photonic crystal nano-sensor works at the resonance wavelength λ = 1733 nm and with the TE polarization. The maximum transmission efficiency, quality factor, and sensitivity are 100%, 582.66, and 33.33 pm/°C, respectively. This nano temperature sensor, designed to work in the nanoscale, can sense the slightest temperature change, so it is well suited for critical and sensitive nanotechnology systems. تفاصيل المقالة -
حرية الوصول المقاله
57 - Biosensor for detection of biological components using photonic crystal
Zohreh DorraniIn biosensors, the investigated material is biological components such as cells, proteins, and nucleic acids. All compounds of living organisms have sensors with functions similar to mechanical sensors. Most of these sensors are special cells sensitive to the external e أکثرIn biosensors, the investigated material is biological components such as cells, proteins, and nucleic acids. All compounds of living organisms have sensors with functions similar to mechanical sensors. Most of these sensors are special cells sensitive to the external environment's physical characteristics such as light, movement, temperature, magnetic field, gravity, humidity, vibration, pressure, electric fields, sound, etc. Biosensors can be made using photonic crystals, an example of which is designed here. In order to check the biomolecule detection ability by the biosensor, the refractive index around the sensing hole is changed and the output transmission spectrum is limited. By changing the refractive index, the transmission spectrum can be measured, which enables the sensor to identify biological molecules. In this study, a sensor was designed that is capable of detecting biological molecules. This sensor has good sensitivity, which makes it capable of measuring in a small size. The sensor can accurately predict the result, so this sensor is very suitable for medical purposes. تفاصيل المقالة -
حرية الوصول المقاله
58 - Arbitrary Angle Waveguide Bends Made of a New Heterostructure Phononic Crystal
M Bagherinouri M MoradiIn this paper, an arbitrary angle waveguide bend made of a new heterostructure phononic crystal has been studied. By creation of line defects in the proposed heterostructure which is composed of square and rhombus phononic crystals, a simple structure waveguide bend wit أکثرIn this paper, an arbitrary angle waveguide bend made of a new heterostructure phononic crystal has been studied. By creation of line defects in the proposed heterostructure which is composed of square and rhombus phononic crystals, a simple structure waveguide bend with arbitrary angles is made. Analyzing the proposed bend showed that by creating line defects in the composition of the square and equilateral triangle lattices, 30˚ waveguide bend can be realized. Also the study showed that by creating line defects in the composition of the square and rhombus lattices, 40˚ (20˚) waveguide bend could be obtained if the angular constant of the rhombus lattice is 80˚ (40˚). The 40˚ and 20˚ waveguide bends have a narrow pass band which can be utilized as a filter to separate a specific frequency and guide it along a defined pass. Also the study shows that by incorporation of 90˚ bend within the presented heterostructure bends, waveguide bends can be realized that guide elastic waves in the arbitrary angles greater than 90˚. تفاصيل المقالة -
حرية الوصول المقاله
59 - Mechanical Characteristics and Failure Mechanism of Nano-Single Crystal Aluminum Based on Molecular Dynamics Simulations: Strain Rate and Temperature Effects
R Rezaei H Tavakoli-Anbaran M ShariatiBesides experimental methods, numerical simulations bring benefits and great opportunities to characterize and predict mechanical behaviors of materials especially at nanoscale. In this study, a nano-single crystal aluminum (Al) as a typical face centered cubic (FCC) me أکثرBesides experimental methods, numerical simulations bring benefits and great opportunities to characterize and predict mechanical behaviors of materials especially at nanoscale. In this study, a nano-single crystal aluminum (Al) as a typical face centered cubic (FCC) metal was modeled based on molecular dynamics (MD) method and by applying tensile and compressive strain loadings its mechanical behaviors were investigated. Embedded atom method (EAM) was employed to represent the interatomic potential of the system described by a canonical ensemble. Stress-strain curves and mechanical properties including modulus of elasticity, Poisson’s ratio, and yield strength were determined. Furthermore, the effects of strain rate and system temperature on mechanical behavior were obtained. It was found that the mechanical properties exhibited a considerable dependency to temperature, but they hardly changed with increase of strain rate. Moreover, nucleation and propagation of dislocations along the plane of maximum shearing stress were the mechanisms of the nanocrystalline Al plastic deformation. تفاصيل المقالة -
حرية الوصول المقاله
60 - Eocene-Oligocene volcanic units of momen abad, east of Iran: petrogenesis and magmatic evolution
Sahar Tarabi Mohamad Hashem Emami Sourosh Modabberi Seyed Jamal Sheikh ZakariaeeThis study investigates petrology and major, minor, and rare earth elements ‎geochemistry of ‎East Iranian Eocene–Oligocene volcanic rocks in Sistan suture ‎zone, to examine their ‎petrogenesis and magma evolution. The volcanic rocks include andesi أکثرThis study investigates petrology and major, minor, and rare earth elements ‎geochemistry of ‎East Iranian Eocene–Oligocene volcanic rocks in Sistan suture ‎zone, to examine their ‎petrogenesis and magma evolution. The volcanic rocks include andesite, trachy-andesite, dacite ‎and rhyolite. ‎These calc-alkaline rocks of high-K series are enriched in Large ‎Ion Lithophile ‎Elements of Rb and Ba and depleted in High Field Strength Elements ‎(e.g. Ti and Nb). The REE ‎pattern shows Eu negative anomaly. These ‎features are comparable with rocks in subduction ‎zone of continental ‎margin setting. ‎The petrographic features and the geochemical variation ‎of major oxides and trace ‎elements against SiO2 can be related to fractional ‎crystallization in parent magma. The trace ‎element ratios, e.g. Nb/La, Nb/U, Ba/Rb, Nb/Y and Rb/Y, verify crustal ‎contamination with a remarkable upper ‎crustal contamination as the main ‎process in the ‎formation of volcanic series. ‎The ratios of Nb/Ba and Nb/Zr indicate that magmatic activity in Momen Abad had ‎resulted ‎from sub-continental lithospheric mantle. In addition, Nb/Y and Zr/Yb versus ‎Ta/Yb reveals an ‎E-MORB like mantle source. A spinel lherzolite composition ‎with significant role of the ‎AFC processes are deduced from the concentrations of Yb and ‎Y, and the ratios of Th/Yb and ‎La/Yb. ‎The Ba/Nb, Ba/Th and Th/Nb ratios presume a metasomatized mantle source ‎resulted from ‎the melting of upper crust sediments inherited from the subduction of ‎Neotethys ocean beneath ‎the Lut Block. ‎ تفاصيل المقالة -
حرية الوصول المقاله
61 - Deletion of Auramine O and Crystal Violet from Industrial Aqueous Solution on to Albizia Lebbeck Leaves-Capped Silver Nanoparticles Synthesis Investigating Parameters Equilibrium
Fatemah Maghami Maryam AbrishamkarThe applicability of Albizia Lebbeck Leaves-capped silver nanoparticles (ALL-AgNPs) synthesis to dyes removal from aqueous solutions has been reported. The main goal of this work was development of a practical system to acquire the optimal conditions of removal accompan أکثرThe applicability of Albizia Lebbeck Leaves-capped silver nanoparticles (ALL-AgNPs) synthesis to dyes removal from aqueous solutions has been reported. The main goal of this work was development of a practical system to acquire the optimal conditions of removal accompanied by ultrasonic for maximizeing removal of Auramine O (AO) and Crystal Violet (CV) onto ALL-AgNPs in aqueous solution based on RSM (response surface methodology). To characterization of this novel materials techniques of X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and scanning electron microscopy (SEM) were employed. The influences of several parameters including initial AO concentration (X1), initial CV concentration (X2), pH (X3), adsorbent dosage (X4), sonication time (X5) evaluated based on CCD (central composite design) using RSM. The process was empirically modeled to reveal the significant variables and their possible interactions. The optimal prameters of ultrasound time, pH, adsorbent mass, AO and CV concentration were obtained 5 min, 6.0, 0.025 g, 25 mg L-1, respectively. The application of isotherms in obtaining the thermodynamic parameters like enthalpy (ΔH0), free energy (ΔG0) and entropy (ΔS0) for adsorption process were confirmed. The maximum monolayer capacities (Q max) of AO and CV were obtained 73.2 and 48.7 mg/g, respectively under optimal conditions. تفاصيل المقالة -
حرية الوصول المقاله
62 - Synthesis of Nano-Sized Titania Particles by Hydrolysis of Titanium Tetrachloride
M. Farahmandjou M. RamazaniNano-sized titanium dioxide TiO2 powder was successfully prepared from its precursor titanium (IV) chloride by a simple and new wet chemical method. TiCl4 were used as precursor in hydrogen peroxide, H2O2 and ethanol. This solution was then peptized using nitric acid an أکثرNano-sized titanium dioxide TiO2 powder was successfully prepared from its precursor titanium (IV) chloride by a simple and new wet chemical method. TiCl4 were used as precursor in hydrogen peroxide, H2O2 and ethanol. This solution was then peptized using nitric acid and heated under reflux at 80°C. Their physico-chemical properties were then characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-Ray diffraction (XRD). The TEM results showed that the size of as-synthesized TiO2 nanoparticles were in the range of 7-10 nm. The SEM images showed that the size of nanoparticles increased when the nanoparticles prepared in presence of nitric acid. The SEM images showed that the quality of annealed TiO2 nanoaprticles, increased when the nanoparticles synthesized without nitric acid. The crystal structure of the nanoparticles before and after annealing was done by XRD analysis. It was realized that the rutile phase was formed after heat treatment at 600°C. XRD pattern also showed that the size of annealed TiO2 nanoparticles increased from 20 to 50 nm when the nanoparticles prepared with nitric acid. تفاصيل المقالة -
حرية الوصول المقاله
63 - An Efficient Green Synthesis of Copper Oxide NanoCrystalline
M. Kargar M. Ghashang M.R. Mohammad ShafieeIn this study, a feasible green method for the synthesis of copper oxide nanocrystalline is described by using sour cherry juice which has a significant effect on crystalline size, and morphology. The benefits of the green method, not only nanometer scale are formed but أکثرIn this study, a feasible green method for the synthesis of copper oxide nanocrystalline is described by using sour cherry juice which has a significant effect on crystalline size, and morphology. The benefits of the green method, not only nanometer scale are formed but also low-cost method are obtained in a normal atmosphere which it has been used (CH3COO)2Cu.H2O individually as Cu sources. All samples have calcination in 600°C. The effect of sour cherry juice concentration to control crystal growth is investigated by changing the amount of it to 20, 40, and 80 mL, respectively. The synthesized particles are characterized by using X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FE-SEM). Powder X-ray Diffraction analysis confirms that pure Copper Oxide nanocrystallines are in a single phase monoclinic structure which the average crystalline size has estimated via Williamson-Hall plot from the highest peak of the XRD was among 15-55 nm for all samples. تفاصيل المقالة -
حرية الوصول المقاله
64 - بررسی برخی خصوصیات ژنی جدایههای بومی باکتری Bacillus thuringiensis از خاکهای مناطق جنگلی استان گلستان
مرضیه شازده احمدی سید افشین سجادی زینالعابدین شهادتی مقدمجدایه های بومی باکتری Bacillus thuringiensis (Bt) از خاک های مناطق جنگلی شهرستان های مختلف استان گلستان جدا سازی و ژن Cry و Vip عامل تولید توکسین و پروتئین مؤثر روی حشرات در آن ها ردیابی شد. از کل 42 نمونه خاک مورد بررسی از طریق بازدارندگی انتخابی استات سدیم، تعداد 160 أکثرجدایه های بومی باکتری Bacillus thuringiensis (Bt) از خاک های مناطق جنگلی شهرستان های مختلف استان گلستان جدا سازی و ژن Cry و Vip عامل تولید توکسین و پروتئین مؤثر روی حشرات در آن ها ردیابی شد. از کل 42 نمونه خاک مورد بررسی از طریق بازدارندگی انتخابی استات سدیم، تعداد 160 جدایه Bt جدا سازی گردید. پس از کشت کلنی ها، رنگ آمیزی اختصاصی و شناسایی میکروسکوپی در 40 درصد از جدایه ها انجام شد، پروتئین کریستالی کشنده برای بسیاری از حشرات مشاهده گردید. بررسی مولکولی جدایه های Bt نشان داد که در 12 جدایه ژن هایCry و Vip وجود داشتند. آزمایشات تعیین ساختار ژنی برای وجود سه ژن Cry 1A (شامل Cry1Aa, Cry1Ab, Cry1Ac) و ژن های Cry1I، Cry1F، Cry2، Cry9 و Vip3Aa با استفاده از 8 جفت آغاز گر اختصاصی انجام شد. ژن های Cry1Ab، Cry2 و Cry1F در همه جدایه ها مشاهده شد، ولی ژن های Cry1Aa، Cry1I و Cry1Ac فراوانی بسیار کم (کم تر از 20 درصد) داشتند و یا در هیچ یک از جدایه ها یافت نشدند. نتایج این تحقیق می تواند برای ردیابی جدایه های بومی باکتری Bt که دارای پروتئین های کریستالی مؤثر روی حشرات هستند، مفید واقع شود. تفاصيل المقالة -
حرية الوصول المقاله
65 - اثر آب معدنی چشمه کندوان بر سنگهای کلیوی اگزالات کلسیمی در موشهای صحرایی نر بالغ
فاطمه رسولیان علیرضا صادقی پوربیماری سنگ کلیه یک مشکل جهانی است و وابسته به نژاد، منطقه جغرافیایی و یا فرهنگی نمی باشد. در پژوهش حاضر اثر آب معدنی چشمه کندوان بر جلوگیری از تشکیل کریستال‎های اگزالات کلسیم در موش‎های صحرایی نر مورد بررسی قرار گرفته است. کریستالیزاسیون اگزالات کلسیم توسط اضاف أکثربیماری سنگ کلیه یک مشکل جهانی است و وابسته به نژاد، منطقه جغرافیایی و یا فرهنگی نمی باشد. در پژوهش حاضر اثر آب معدنی چشمه کندوان بر جلوگیری از تشکیل کریستال‎های اگزالات کلسیم در موش‎های صحرایی نر مورد بررسی قرار گرفته است. کریستالیزاسیون اگزالات کلسیم توسط اضافه نمودن کلرید آمونیوم و اتیلن گلیکول در آب آشامیدنی به ترتیب به مدت 3 و 35 روز القاء شد. گروه کنترل توسط آب آشامیدنی تیمار شد. گروه کنترل بیمار کلرید آمونیوم و اتیلن گلیکول را در آب آشامیدنی به ترتیب 3 و 35 روز دریافت کردند. گروه تجربی کلرید آمونیوم و اتیلن گلیکول را در آب معدنی چشمه کندوان به ترتیب به مدت 3 و 35 روز دریافت کردند. بعد از 38 روز، حیوانات توسط اتر بیهوش شده و کلیه سمت چپ آنها خارج شده و در فیکساتیو قرار گرفت. نمونه‎ها برای مطالعات بافت‎شناسی آماده شده و توسط هماتوکسیلین - ائوزین رنگ‎آمیزی شدند. نتایج نشان داد تیمار آب چشمه کندوان موجب کاهش تعداد کریستال‎های اگزالات کلسیم در بافت کلیه حیوانات تجربی در مقایسه با گروه کنترل بیمار می‎گردد. همچنین، تیمار آب معدنی کندوان آسیب توبولو - اینتراستیشیال را دربافت کلیه حیوانات تیمار شده کاهش می‎دهد. بنابراین، آب چشمه کندوان می‎تواند مانع تشکیل کریستال های اگزالات کلسیم در کلیه شود. تفاصيل المقالة -
حرية الوصول المقاله
66 - اثر عصاره هیدرو-اتانلی دانه زنیان (Trachyspermum copticum L.) بر جلوگیری از تشکیل کریستالهای اگزالات کلسیم در بافت کلیه موشهای صحرایی نر بالغ
علیرضا صادقی پور علی مازوجیشکیل سنگ های ادراری یک مشکل جهانی است و هیچ گروه نژادی، جغرافیایی و فرهنگی را در بر نمی گیرد. انواع متعددی از سنگ های ادراری بر اساس ترکیب شیمیایی وجود دارند. سنگ های آهکی معمول ترین سنگ های کلیه هستند که بیش از 80% سنگ ها را تشکیل می دهند. سنگ های اگزالات کلسیم معمول ت أکثرشکیل سنگ های ادراری یک مشکل جهانی است و هیچ گروه نژادی، جغرافیایی و فرهنگی را در بر نمی گیرد. انواع متعددی از سنگ های ادراری بر اساس ترکیب شیمیایی وجود دارند. سنگ های آهکی معمول ترین سنگ های کلیه هستند که بیش از 80% سنگ ها را تشکیل می دهند. سنگ های اگزالات کلسیم معمول ترند. در طب سنتی ایران، گیاهان دارویی بسیاری برای درمان سنگ های کلیوی استفاده می شوند. هدف از مطالعه حاضر، بررسی اثر عصاره هیدرواتانلی بخش های هوایی گیاه دم اسب بر کریستالیزاسیون اگزالات کلسیم در بافت کلیه موشهای صحرایی نر نژاد ویستار میباشد. در پژوهش تجربی حاضر در ابتدا، عصاره هیدرواتانلی گیاه در غلظتهای 25، 50 و 100 میلیگرم بر کیلوگرم تهیه شد. کریستالیزاسیون اگزالات کلسیم توسط اضافهنمودن کلرید آمونیوم و اتیلن گلیکول در آب آشامیدنی بهترتیب بهمدت 3 و 38 روز القاء شد. گروه کنترل توسط آب آشامیدنی تیمار شدند. گروههای تجربی علاوه بر آب آشامیدنی حاوی کلرید آمونیوم و اتیلن گلیکول توسط غلظتهای 25، 50 و 100 میلیگرم بر کیلوگرم عصاره گیاه به روش درونصفاقی به مدت 41 روز تیمار شدند. بعد از 41 روز، حیوانات توسط اتر بیهوش شده و کلیه سمت چپ آنها خارج شده و در فیکساتیو قرار گرفت. نمونهها برای مطالعات بافتشناسی آماده شده و توسط هماتوکسیلین-ائوزین رنگآمیزی شدند. نتایج نشان دادند که تیمار عصاره موجب کاهش تعداد کریستالهای اگزالات کلسیم در بافت کلیه حیوانات تجربی در مقایسه با گروه کنترل بیمار میگردد. همچنین، تیمار عصاره آسیب توبولو-اینتراستیشیال را در حیوانات تیمار شده کاهش میدهد. بنابراین، گیاه میتواند مانع تشکیل سنگ کلیه در حیوانات تیمار شده گردد تفاصيل المقالة -
حرية الوصول المقاله
67 - اثرات لیتولیتیک عصاره هیدروالکلی گیاه دم اسب در موشهای صحرایی نر
مریم عیدی علیرضا صادقی پور علی مازوجی رضا قهرمانیهدف از مطالعه حاضر، بررسی اثر تیمار عصاره هیدروالکلی بخش هوایی دم اسب بر تعداد کریستالهای تشکیل شده در بافت کلیه و نیز آسیب بافتی در مقایسه با حیوانات کنترل میباشد. در ابتدا، عصاره هیدروالکلی گیاه در غلظتهای مختلف تهیه شد. کریستالیزاسیون اگزالات کلسیم در کلیه حیوانات أکثرهدف از مطالعه حاضر، بررسی اثر تیمار عصاره هیدروالکلی بخش هوایی دم اسب بر تعداد کریستالهای تشکیل شده در بافت کلیه و نیز آسیب بافتی در مقایسه با حیوانات کنترل میباشد. در ابتدا، عصاره هیدروالکلی گیاه در غلظتهای مختلف تهیه شد. کریستالیزاسیون اگزالات کلسیم در کلیه حیوانات توسط اضافهنمودن کلرید آمونیوم و اتیلنگلیکول در اب آشامیدنی بهترتیب بهمدت 3 و 38 روز القاء شد. گروه کنترل توسط آب آشامیدنی تیمار شدند. گروههای تجربی علاوه بر آب آشامیدنی حاوی کلرید آمونیوم و اتیلن گلیکول توسط غلظتهای مختلف عصاره گیاه به روش درونصفاقی به مدت 41 روز تیمار شدند. بعد از 41 روز، حیوانات توسط اتر بیهوش شده و کلیه سمت چپ آنها خارج شده و در فیکساتیو قرار گرفت. نمونهها برای مطالعات بافتشناسی آماده شده و توسط هماتوکسیلین-ائوزین رنگآمیزی شدند. نتایج نشان دادند که تیمار عصاره هیدروالکلی بخش هوایی گیاه دم اسب موجب کاهش تعداد کریستالهای اگزالات کلسیم در بافت کلیه حیوانات تجربی در مقایسه با گروه کنترل بیمار میگردد. همچنین، تیمار عصاره گیاه موجب کاهش آسیب توبولو-اینتراستیشیال در حیوانات تیمار شده میگردد. بنابراین کاربرد سنتی این گیاه برای درمان سنگ کلیه مورد تایید قرار گرفت. تفاصيل المقالة -
حرية الوصول المقاله
68 - اثر عصاره الکلی دانه گشنیز (Coriandrum sativum L.) بر جلوگیری از تشکیل کریستال های اگزالات کلسیم در بافت کلیه موشهای صحرایی نر بالغ
حسین احمدیان علیرضا صادقی پور مصطفی حمیدی نعمانیهدف از مطالعه حاضر، بررسی اثر عصاره هیدروالکلی دانه گشنیز بر کریستالیزاسیون اگزالات کلسیم در موشهای صحرایی نر نژاد ویستار میباشد. در ابتدا، عصاره هیدروالکلی گیاه در غلظتهای 100، 150، 200 و 300 میلیگرم بر کیلوگرم تهیه شد. کریستالیزاسیون اگزالات کلسیم توسط اضافهنمودن أکثرهدف از مطالعه حاضر، بررسی اثر عصاره هیدروالکلی دانه گشنیز بر کریستالیزاسیون اگزالات کلسیم در موشهای صحرایی نر نژاد ویستار میباشد. در ابتدا، عصاره هیدروالکلی گیاه در غلظتهای 100، 150، 200 و 300 میلیگرم بر کیلوگرم تهیه شد. کریستالیزاسیون اگزالات کلسیم توسط اضافهنمودن کلرید آمونیوم و اتیلنگلیکول در آب آشامیدنی بهترتیب بهمدت 3 و 35 روز القاء شد. گروه کنترل توسط آب آشامیدنی تیمار شدند. گروههای تجربی علاوه بر آب آشامیدنی حاوی کلرید آمونیوم و اتیلن گلیکول توسط غلظتهای 100، 150،200 و 300 میلیگرم بر کیلوگرم عصاره گیاه به روش درونصفاقی به مدت 38 روز تیمار شدند. بعد از 38 روز، حیوانات توسط اتر بیهوش شده و کلیه سمت چپ آنها خارج شده و در فیکساتیو قرار گرفت. نمونهها برای مطالعات بافتشناسی آماده شده و توسط هماتوکسیلین-ائوزین رنگآمیزی شدند. نتایج نشان دادند که تیمار عصاره موجب کاهش تعداد کریستالهای اگزالات کلسیم در بافت کلیه حیوانات تجربی در مقایسه با گروه کنترل بیمار میگردد. همچنین، تیمار عصاره آسیب توبولو-اینتراستیشیال را در حیوانات تیمار شده کاهش میدهد. بنابراین، گیاه میتواند مانع تشکیل سنگ کلیه در حیوانات تیمار شده گردد. تفاصيل المقالة -
حرية الوصول المقاله
69 - Design of a new narrow band channel drop filter based on photonic crystal ring resonator
aram khoshtinat Mohammad ghiamyIn this design an optical ring resonator are embedded between two Horizontal input and output waveguides which has 4 orbitals around the center of the resonator so that each orbital consists of 8 rods with different size in which radius of larger orbitals rods are bigge أکثرIn this design an optical ring resonator are embedded between two Horizontal input and output waveguides which has 4 orbitals around the center of the resonator so that each orbital consists of 8 rods with different size in which radius of larger orbitals rods are bigger than radius of smaller orbitals rods. The analysis of simulation results showed the proposed filter has the transmission efficiency 100% at the resonance wavelength of 1550 nm, bandwidth and quality factor are 0.2 and 7753 respectively which proves it is a suitable filter for optical communication applications. Ultra-low bandwidth and high transmission efficiency are the most important advantages of the proposed filter in this study. تفاصيل المقالة -
حرية الوصول المقاله
70 - A Novel Structure for Optical Channel Drop Filter using Two-Dimensional Photonic Crystals with Square Lattice
aram khoshtinat Mohammad GhiamyIn the present paper a novel structure for optical channel drop filter (CDF) based on photonic crystal ring resonator with circular core has been proposed. In order to design the proposed CDF, the plan wave expansion (PWE) method is applied for calculation of band struc أکثرIn the present paper a novel structure for optical channel drop filter (CDF) based on photonic crystal ring resonator with circular core has been proposed. In order to design the proposed CDF, the plan wave expansion (PWE) method is applied for calculation of band structure and photonic band gap while the transmission characteristics of proposed CDF have been calculated using the finite difference time domain (FDTD) method. The transmission efficiency of 100%, quality factor of 2583 and bandwidth of 0.6 are achieved at wavelength near to 1550 nm which proved this filter is usable and suitable for optical communication applications. تفاصيل المقالة -
حرية الوصول المقاله
71 - New Design of Mems piezoresistive pressure sensor
Hamsa Kamali Asghar charminThe electromechanical analysis of a piezoresistive pressure microsensor with a square-shaped diaphragm for low-pressure biomedical applications is presented. This analysis is developed through a novel model and a finite element method (FEM) model. A microsensor with a d أکثرThe electromechanical analysis of a piezoresistive pressure microsensor with a square-shaped diaphragm for low-pressure biomedical applications is presented. This analysis is developed through a novel model and a finite element method (FEM) model. A microsensor with a diaphragm 1000 „m length and with thickness=400 µm is studied. The electric response of this microsensor is obtained with applying voltage into senseor in p-type piezoresistors located on the diaphragm surface. The diaphragm that is 10 „m thickexhibits a maximum deflection of 3.74 „m using the designed model, which has a relative difference of 5.14 and 0.92% with respect to the comsol model, respectively. The maximum sensitivity and normal stress calculated using the this model are 1.64 mV/V/kPa and 102.1 MPa, respectively. The results of the polynomial model agree well with the Timoshenko model and FEM model for small deflections. In addition, the designed model can be easily used to predict the deflection, normal stress, electric response and sensitivity of a piezoresistive pressure microsensor with a square-shaped diaphragm under small deflections. تفاصيل المقالة -
حرية الوصول المقاله
72 - Optimizing maximum rate of normalized power of terahertz switch constant state based on photonic crystals
hosnieh mohammadpour samiyeh matloubPhotonic crystals were made on the basis of structure of natural crystals. Almost, all metal elements and most of insulated elements and compound materials are found in the form of crystal at the nature. At such materials, atoms and molecules play scattering role for el أکثرPhotonic crystals were made on the basis of structure of natural crystals. Almost, all metal elements and most of insulated elements and compound materials are found in the form of crystal at the nature. At such materials, atoms and molecules play scattering role for electron waves. At the present paper, proposed structure of two dimensional photonic crystals having square grid and including silicone circular rods at air background at terahertz extension were studied. Also, electric and magnetic fields were estimated through finite difference method limited at time domain. [1] At this simulation, optic switching was investigated on the basis of photonic crystal structure with one waveguide that the performance of these tools is based on forming faults at photonic crystals affected by Ker nonlinearity.Also optimization was done to increase maximum rate of normalized power of constant state by two parameters including change of silicone cavities and polymer radius. تفاصيل المقالة -
حرية الوصول المقاله
73 - An all optical photonic crystal based FSK demodulator suitable for optical communications
akram asghari govarOptical frequency shift keying demodulator is an optical structure that can generate logic 0 and 1 codes based on the frequency of the input signal. In this paper we proposed and designed a new structure for realizing frequency shift keying demodulator based on photonic أکثرOptical frequency shift keying demodulator is an optical structure that can generate logic 0 and 1 codes based on the frequency of the input signal. In this paper we proposed and designed a new structure for realizing frequency shift keying demodulator based on photonic crystals. The propose structure was designed using resonant cavities. The simulation results show that by setting the frequency of the input signal at 191 THz and 192.3 THz the proposed structure can generate log 0 and 1 bits. The rise time of the proposed structure is about 2 ps. Keywords: Optical Communications, Photonic crystal, FSK demodulator, Resonant cavity. تفاصيل المقالة -
حرية الوصول المقاله
74 - Optimization and evaluation of structural performance in the design of an all-optical nano-switch based on two-dimensional and alternating photon crystal structures used in all-optical circuits
adel habibpourin this paper, a new example of these structures has been designed and simulated using two-dimensional photon crystals. This proposed structure uses point nano-amplifiers to couple light to waveguides, and two input and output waveguides. In the design of this all-optic أکثرin this paper, a new example of these structures has been designed and simulated using two-dimensional photon crystals. This proposed structure uses point nano-amplifiers to couple light to waveguides, and two input and output waveguides. In the design of this all-optical switch, the mechanism of interference effect in photon crystals has been used in order to make the structure simpler and smaller. This optical structure is based on silicon technology and is designed using dielectric rods in an air bed. In this structure, the constant value of the lattice is about 549 nm, the radius of the dielectric rods is about 100 nm and the radius of the nano-optical intensifiers is 30 nm. This structure was active at 1550 nm and by examining at 1559, its performance in switching mode was analyzed. The response rate of the structure was 0.75 ps. The rate of placement losses in the structure for different inputs according to the input power of 1 mW / 2m2 is about -13 dB and the rate of shutdown rate for this input is equal to 12.8 dB. In order to optimize the structure in terms of the effects of the parameters involved in it to examine various factors, including; The input power, wavelength and central frequency, the size of the radius of the nano-resonator rods, the size of the dielectric rods and the fixed network are discussed. In order to analyze the structure in terms of scattering and photon band gap range, PWE method has been used and to analyze and obtain the output spectrum of the structure, FDTD method has been used. Due to the size of 7.86 m2, flexibility and suitable simulation results, this proposed structure is very suitable for applications of optical integrated circuits. تفاصيل المقالة -
حرية الوصول المقاله
75 - Designing Tunable Optical Filter multi-Channel containing 1DDPC Structure
Behnam KazempourAn electro-optic tunable single and multi-channel optical filter based on one-dimensional defective photonic crystal (1DDPC) structure is proposed. A couple of externally tunable defects in arrangement of (AB)5D1(BA)D2(BA)5, where A and B are dielectric materials, D1 an أکثرAn electro-optic tunable single and multi-channel optical filter based on one-dimensional defective photonic crystal (1DDPC) structure is proposed. A couple of externally tunable defects in arrangement of (AB)5D1(BA)D2(BA)5, where A and B are dielectric materials, D1 and D2 are the tunable defects are used. The defects are composed of the ferroelectric LiNbO3 crystals and two pairs of thin Ag layers to make the voltage connections. With this arrangement it is possible to apply different external biases that facilitate the tunability and even more adjustability of the channel frequencies. Depending on the thickness of defect layers, a single or multi resonant peak can be induced inside the photonic band gap which can be employed to filter channels. About 37 nm (46 nm) of blue shift for 300 V and 37 nm (37 nm) of red shift for -300 V biases are observed without (and with) loss incorporation. An important and notable effect that happened was the dispersion loss of the structure due to metal layers is compensated by the negative biases. Our proposed structure can be good candidate to design an externally tunable optical filter and a voltage sensor with potential applications in all-optical signal processing and information communications fields. تفاصيل المقالة -
حرية الوصول المقاله
76 - The New Method for Optical Channel Drop Filter with High Quality Factor Based on Triangular Photonic Crystal Design
ابولفضل اسدپور حامد علیپور بنایی علیرضا عندلیبWe have designed a new type of optical channel drop filter (CDF) based on two dimensionaltriangular lattice photonic crystals. CDF operation is based on coupling to the photonic crystalwaveguide. The proposed structure is optimized to work as a CDF for obtaining the CDF أکثرWe have designed a new type of optical channel drop filter (CDF) based on two dimensionaltriangular lattice photonic crystals. CDF operation is based on coupling to the photonic crystalwaveguide. The proposed structure is optimized to work as a CDF for obtaining the CDFcharacteristics and band structure of the filter the finite difference time domain (FDTD) method andplane wave expansion (PWE) method are used respectively. Dropping efficiency at 1550nm andquality factor (Q) of our proposed structure are 96.36 % and 282.7, respectively. The quantities تفاصيل المقالة -
حرية الوصول المقاله
77 - A New Design of Photonic Crystal Filter and Power Splitter Based on Ring Resonators
رضا قویدل بارساری علیرضا عندلیب حامد علیپور بناییHere, we propose an optical filter and an optical power splitter based on two-dimensionalphotonic crystal all circular ring resonators. These structures are made of a square lattice ofsilicon rods with the refractive index n1=3.464 surrounded by air (with refractive ind أکثرHere, we propose an optical filter and an optical power splitter based on two-dimensionalphotonic crystal all circular ring resonators. These structures are made of a square lattice ofsilicon rods with the refractive index n1=3.464 surrounded by air (with refractive indexn2=1). First, we have designed the filter and by using that, we designed a power splitter. Thetransmission efficiency and Quality factor for both, an optical filter and an optical powersplitter, respectively, are more than 90% and 1000. Resonant modes of the all-circular ringresonator with their corresponding degenerated poles and the transmission spectra arecalculated using the PWE, and 2D-FDTD methods respectively. تفاصيل المقالة -
حرية الوصول المقاله
78 - The New Design and Simulation of an Optical Add Drop Filter Based On Hexagonal Photonic Crystal Single Ring Race Track Resonator
ابولفضل عباسپور حامد علیپور بنایی علیرضا عندلیبIn this paper, using annular resonator we have designed an adding and dropping filter light based ontwo-dimensional photonic crystals. The shape of ring resonator filter adding and dropping that wehave proposed is Race Track. This filter has a hexagonal lattice structur أکثرIn this paper, using annular resonator we have designed an adding and dropping filter light based ontwo-dimensional photonic crystals. The shape of ring resonator filter adding and dropping that wehave proposed is Race Track. This filter has a hexagonal lattice structure of silicon bars withrefractive index 3/46 that is located in the context of air with refractive index 1. Transmissionefficiency and quality coefficient of our proposed filter are respectively 94% and 310. Finite differencemethod in two-dimensional time domain (2-D FDTD) used for normalized transmission spectra ofphotonic crystal ring resonator and to calculate the photonic band, plane wave expansion method(PWE) has been used. تفاصيل المقالة -
حرية الوصول المقاله
79 - Optical Filter Based On Point Defects in 2D Photonic Crystal Structur
آرزو مالکیIn this paper, we proposed a novel structure for designing all optical filter based on photonic crystal structure. In designing the proposed filter, we simply employed a point defect localized between input and output waveguides as wavelength selecting part of the filte أکثرIn this paper, we proposed a novel structure for designing all optical filter based on photonic crystal structure. In designing the proposed filter, we simply employed a point defect localized between input and output waveguides as wavelength selecting part of the filter. The initial form of this filter is capable of selecting optical waves at =1560 nm, the transmission efficiency of the filter is 100%. In designing and studying the optical properties of the filter, we used plane wave expansion and finite difference time domain methods. After designing the filter, we studied the impact of different parameters on the filtering behavior of the structure. The total footprint of the filter is less than 100 100 m2. Simplicity of design and ultra-compact dimensions are the most significant characteristics of our filter. تفاصيل المقالة -
حرية الوصول المقاله
80 - The effect of cells' radius on optical filter output spectrum based on photonic crystals
Jabraeil Farajzadeh Mir Mansur ZiabariIn this article, the effect of cells' radius on the behavior of wavelength switching optical filter andthe effect of the radius of the optical filters' key characteristics such as wavelength resonance onan optical filter based on photonic crystals, have been investigate أکثرIn this article, the effect of cells' radius on the behavior of wavelength switching optical filter andthe effect of the radius of the optical filters' key characteristics such as wavelength resonance onan optical filter based on photonic crystals, have been investigated. Currently, the most commonapplied mechanism for designing optical filter based on photonic crystals is using twomechanisms such as (a) The resonant cavities and (b) Ring resonators. The applied mechanism inoptical filter used in this article is the resonant cavities. In this filter, filtering act is operated byusing cavity located between output Waveguide and input waveguide and it has been used todesign filter at the first extracted band structure and we have applied forbidden band photonicbased-crystal by using PWE method. Then, the calculations related to filter output spectrum werecarried out by using an FDTD method. Thus, the effect of cells' radius on the behavior ofwavelength switching optical filter has been investigated in this study. تفاصيل المقالة -
حرية الوصول المقاله
81 - Development of rejuvenation process in Iranian industrial heritage based on Grounded theory
Mehdi Khakzand Mohammad Javad PorkarToday, one of the most important issues related to the industrial heritage in Iran is the rejuvenation and reuse of such assets. The industrial buildings dating from the Pahlavi era (1925-1978) have the adaptive capacity to create modern spaces. The present study seeks أکثرToday, one of the most important issues related to the industrial heritage in Iran is the rejuvenation and reuse of such assets. The industrial buildings dating from the Pahlavi era (1925-1978) have the adaptive capacity to create modern spaces. The present study seeks to answer this question: “How is the developmental approach formed with regard to industrial heritage?” Therefore, some indicators were extracted using Grounded Theory that include four effective criteria for the revitalization of industrial heritage; so they are : the effect of hidden values on the improvement of industrial heritage, capacity to adapt to new conditions, a consistent relationship between old and new structures, and development of a new combination. The study explained a theory called "Crystallization of Industrial Heritage" by analyzing the above-mentioned indicators. As myths can be crystallized in contemporary literature, it is thus possible for the industrial heritage to be crystallized in each period. Research findings show that this approach can be generalized to the revitalization of industrial heritage. In this regard, the study focused on how the industrial heritage is crystallized and the adaptation of this theory in the development of three Iranian projects. This process in the development of the Qasr cultural complex shows that this complex succeeded in inspiring crystallization once again in the modern era by creating a significant relationship between the past and present. This creativity, which is the result of combining historical aspects and modern structures for redesigning the building, transformed different old and new components into a single entity at the present era. Consequently, this not only reflects its historical identity but also represents its former values in the contemporary era. However, definition of a spatial organization consistent with the old body in two other cases has allowed for the presence of this legacy in the modern era. تفاصيل المقالة -
حرية الوصول المقاله
82 - On the Relationships of Iranian EFL Learner’s Crystallized and Fluid Intelligences with their Vocabulary Size
Samaneh Maroufolzakerin Akram FaravaniThe aim of the present study was to investigate the relationships of Iranian EFL Learner’s Crystallized and Fluid Intelligences with their Vocabulary Size. The Participants of the study were 100 male and female learners from Islamic Azad University of Mashhad in T أکثرThe aim of the present study was to investigate the relationships of Iranian EFL Learner’s Crystallized and Fluid Intelligences with their Vocabulary Size. The Participants of the study were 100 male and female learners from Islamic Azad University of Mashhad in TEFL course that are ranged from 20 to 40 years old. To administer the study, an experimental and quantitative analysis was conducted and the relationship between variables was measured using three instruments namely, Baddeley’s (1968) Grammatical reasoning Test for Fluid intelligence, Persian C-Test (2015) for crystalized intelligence, and Nation’s (2012) vocabulary size Test. Data were analyzed using SPSS version 21. First, correlational analyses were conducted to find out correlation coefficients between the variables. Then, multiple coefficient tests were done to find Beta weight of variables. The results obtained from correlational analyses showed that there is a significant relationship between crystallized intelligence and vocabulary size, while there is no significant relationship between learners’ fluid intelligence and their vocabulary size. Besides, regression analyses showed that the model consisting of both crystallized and fluid intelligences explains a small but significant portion (8%) of the variance in vocabulary size. It was also concluded that fluid intelligence does not significantly predict vocabulary size, but crystallized intelligence significantly predicts vocabulary size. The study implies that crystalized intelligence should be considered in language learners’ curriculum to achieve the teaching and learning purposes. تفاصيل المقالة -
حرية الوصول المقاله
83 - بررسی فراوانی کریستالاوری و باکتریاوری در سگهای خانگی شهرستان اهواز
بهمن مصلی نژاد سیده میثاق جلالی داریوش غریبی هادی طاهرزادهیکی از مهم ترین عواملی که در پاتوژنز سنگ های ادراری نقش دارد، کریستال اوری می باشد. نوع کریستال می تواند با عفونت باکتریایی دستگاه ادراری مرتبط باشد و متعاقبا موجب تغییر pHادرار گردد. مطالعه حاضر، با هدف ارزیابی فراوانی کریستال اوری و باکتری اوری، در سگ های خانگی اهواز أکثریکی از مهم ترین عواملی که در پاتوژنز سنگ های ادراری نقش دارد، کریستال اوری می باشد. نوع کریستال می تواند با عفونت باکتریایی دستگاه ادراری مرتبط باشد و متعاقبا موجب تغییر pHادرار گردد. مطالعه حاضر، با هدف ارزیابی فراوانی کریستال اوری و باکتری اوری، در سگ های خانگی اهواز صورت گرفت. بدین منظور، ادرار 101 قلاده سگ سالم و به روش کاتترزدن اخذ شد. در ارزیابی فیزیکی نمونه های ادرار، وزن مخصوص، رنگ، شفافیت و ویژگی های ظاهری و در آنالیز بیوشیمیایی آن ها، وجود هموگلوبین، گلوکز، پروتئین و اجسام کتونی در ادرار بررسی و نیز pHادرار سنجیده شد. رسوب ادراری، از نظر حضور کریستال ها، کست ها و سلول ها هم ارزیابی شد. همچنین نمونه های ادرار از نظر حضور باکتری های استافیلوکوکوس، پروتئوس و اشریشیا کولای بررسی شدند. در مجموع، در 20 مورد (80/19 درصد) کریستال اوری مشاهده گردید، که از این تعداد، 15 مورد (75 درصد) استروویت، 2 مورد (10 درصد) اگزالات کلسیم دی هیدرات، 2 مورد (10 درصد) مخلوط استروویت و اگزالات کلسیم دی هیدرات و 1 مورد (5 درصد) مخلوط اگزالات کلسیم دی هیدرات و بیلی روبین بودند. از 101 نمونه، در 40 مورد (60/39 درصد) کشت ادرار مثبت بود، که از این تعداد، 16 مورد (40 درصد) استافیلوکوکوس اپیدرمیدیس و 12 مورد (30 درصد) اشریشیا کولای بود. در هیچ کدام از نمونه ها، پروتئوس جدا نشد. در مطالعه حاضر، ارتباط معنی داری بین جنس و نژاد با باکتری اوری و کریستال اوری به دست نیامد (05/0<p)، اما تفاوت از نظر سن معنی دار بود به نحوی که با افزایش سن، میزان کریستال اوری و باکتری اوری افزایش یافت (05/0>p). همچنین مشخص گردید که همبستگی نزدیکی بین کریستال اوری و باکتری اوری در سگ ها وجود دارد. تفاصيل المقالة -
حرية الوصول المقاله
84 - Design sensitive plasmonic based 1D photonic crystal biosensor with graphene-two metal layer
Maryam Sharifi Sadeq Mohammed Ameen MahmoodIn the present paper , we propose surface plasmon resonance biosensor in combination with a photonic crystal that works based on changing the refractive index of the biomaterial using the transfer matrix method to diagnose blood components. The proposed biosensor struct أکثرIn the present paper , we propose surface plasmon resonance biosensor in combination with a photonic crystal that works based on changing the refractive index of the biomaterial using the transfer matrix method to diagnose blood components. The proposed biosensor structure is (TiO2/ SiO2)^2 / silver/ gold/ graphene , which gives a narrow angular reflectivity resonance. The performance parameters of biosensor such as sensitivity, detection accuracy reported. Our results show that the sensitivity of the proposed configuration is 150 deg /RIU, which is acceptable compared to the values reported in previous studies and shows better performance of the proposed biosensor. تفاصيل المقالة -
حرية الوصول المقاله
85 - Bandpass Biomedical Color Filter Based on 1-D Photonic Crystal Structure
Hamed Alipour-Banaei Navvab KhorrammaslackWe propose a flexible design for tunable bandpass biomedical color filter based on one-dimensional photonic crystals with introducing defect layers into one dimensional periodic structure which permits localized modes to exist with frequency inside photonic band gap (PB أکثرWe propose a flexible design for tunable bandpass biomedical color filter based on one-dimensional photonic crystals with introducing defect layers into one dimensional periodic structure which permits localized modes to exist with frequency inside photonic band gap (PBG). In the proposed structure we can tune localized modes for manifesting different colors by selecting a specific wavelength in the visible light spectrum and also we tuned localized modes in PBG for RGB wavelengths applicable in biomedical systems. With changing the defect layer refractive index, the tuning of the frequency has been done and therefore this structure is suitable for optical biomedical bandpass filter. تفاصيل المقالة -
حرية الوصول المقاله
86 - Designing real-time biosensors and chemical sensors based on symmetrical photonic crystal heterostructures
maryam sharifi Habib Tajalli Hamid Pashaei Adl Payman TajalliIn this paper, we introduce and analytically demonstrate a novel biosensor based on the light-matter interaction in a classic topological photonic crystal (PC) heterostructure, which consists of two opposite-facing 5-period PCs separated by a microfluidic channel. Becau أکثرIn this paper, we introduce and analytically demonstrate a novel biosensor based on the light-matter interaction in a classic topological photonic crystal (PC) heterostructure, which consists of two opposite-facing 5-period PCs separated by a microfluidic channel. Because of the excitation of topological edge mode (TEM) at the interface of the two PCs, the strong coupling between incident light and TEM produces a high-quality resonance peak, which can be used to detect very small changes in the refractive index of biomaterials such as Jurkat Cells inside the microfluidic channel. The proposed biosensor has a sensitivity as high as 240 nm/RIU and figure of merit (FOM) higher than 250. تفاصيل المقالة -
حرية الوصول المقاله
87 - 1D Photonic Crystal Based-Biosensor for Multiple Biomarkers Detection
Farzaneh Bayat Kazem Jamshidi-GhalehIn this work, a highly sensitive 1D photonic crystal (1DPC) based biosensor is introduced and theoretically studied using the transfer matrix method, which has the capability of detecting multiple biomarkers, simultaneously. An m by n gradient refractive index (GRIN) le أکثرIn this work, a highly sensitive 1D photonic crystal (1DPC) based biosensor is introduced and theoretically studied using the transfer matrix method, which has the capability of detecting multiple biomarkers, simultaneously. An m by n gradient refractive index (GRIN) lens array is introduced to the center of a 1DPC structure as a defect layer that is surrounded by two microfluidic channels. By irradiating a white light source to the structure, a multiplex array of the concentric rainbow appears on the output plane. The frequency range of these rainbows is highly dependent on the effective refractive index of the fluid inside the two microfluidic channels. By functionalizing the surfaces around the channels with an m by n antibody array and interacting with the various biomarkers with them, each element of the rainbow array displays the changes in the concentration of a different biomarker. Any change in the concentration of the biomarkers can cause a variation in the effective refractive index of the fluid and it leads to a shift in the produced rainbow frequency range on the output plane. The size and number of the generated rainbow array can be engineered by the central defect layer's refractive index distribution function. تفاصيل المقالة -
حرية الوصول المقاله
88 - 1D Photonic Crystal-Based Biosensor for Multiple Biomarkers Detection
Farzaneh Bayat Kazem Jamshidi-GhalehIn this paper, a highly sensitive 1D photonic crystal (1DPC) based biosensor is introduced and theoretically studied using the transfer matrix method, which has the capability of detecting multiple biomarkers, simultaneously. An m by n gradient refractive index (GRIN) l أکثرIn this paper, a highly sensitive 1D photonic crystal (1DPC) based biosensor is introduced and theoretically studied using the transfer matrix method, which has the capability of detecting multiple biomarkers, simultaneously. An m by n gradient refractive index (GRIN) lens array is introduced to the center of a 1DPC structure as a defect layer that is surrounded by two microfluidic channels. By irradiating a natural light source to the structure, a multiple array of the concentric rainbow appears on the output plane. The frequency range of these rainbows is highly dependent on the effective refractive index of the fluid inside the two microfluidic channels. By functionalizing the surfaces around the channels with an m by n antibody array along with the interaction of the various biomarkers, each element of the rainbow array displays the changes in the concentration of a different biomarker. Any change in the concentration of the biomarkers can cause a variation in the effective refractive index of the fluid and thus lead to a shift in the generated rainbow frequency range of the output. The size and number of the generated rainbow array may be engineered by using the central defect layer's refractive index distribution function. تفاصيل المقالة -
حرية الوصول المقاله
89 - متنپژوهی و قصهشناسی داستان ملکجمشید
حسن ذوالفقاری سیده زیبا بهروزداستان ملک جمشید، طلسم آصف و حمام بلور یکی از داستانهای عامیانة فارسی و رایج در عصر قاجار و کتابی از آخرین بازماندگان سنت افسانهسرایی ایرانی اثر نقیبالممالک است. ازجمله نوادر قصههای عامه است که مؤلف دارد. نویسندة این کتاب، همان پردازندة امیرارسلان معروف است که به دل أکثرداستان ملک جمشید، طلسم آصف و حمام بلور یکی از داستانهای عامیانة فارسی و رایج در عصر قاجار و کتابی از آخرین بازماندگان سنت افسانهسرایی ایرانی اثر نقیبالممالک است. ازجمله نوادر قصههای عامه است که مؤلف دارد. نویسندة این کتاب، همان پردازندة امیرارسلان معروف است که به دلیل شهرت امیرارسلان، داستان ملک جمشید کمتر شناخته شده است. هدف این مقاله آشنایی اهل ادب با این داستان کمتر شناخته شده و بررسی ابعاد ادبی و اجتماعی و متنشناسی اثر است؛ بنابراین کوشش میشود به روش توصیفی-تحلیلی ضمن معرفی قصه و پردازندۀ داستان، محمدعلی شیرازی معروف به نقیبالممالک، و معرفینسخهها و چاپها و گزارش داستان از سه منظر به قصهشناسی این اثر پرداخته شود: اول جنبههای زبانی و ادبی، دوم جنبههای داستانی و بنمایههای قصه و سوم جنبههای اجتماعی. این پژوهش به روش توصیفی-تحلیلی انجام شده است و دستاورد آن به لحاظ زبانی و ادبی بیانگر اینست که نثر کتاب روان، ساده، شیرین و نزدیک به زبان محاوره است و واژگان، کنایات و ترکیبات عامیانه به فراوانی کاربرد دارد. تشبیه ابزار اصلی نویسنده در توصیفات و بیان ادبی و اغلب برآمده از سنتهای ادبی و تکراریاند. حوادث اصلی داستان بر محور جنگ، عشق و بازگشت به سرزمین پدری شکل میگیرد. حوادث داستان همگی از بنمایههای رایج افسانههاست. برخی آداب و رسوم مربوط به جنبههای گوناگون زندگی، حکومت و جنگ را در خلال داستان میتوان یافت که بازتابندۀ آداب و رسوم زمانه است و برخی از پیشههای مورد اشاره در داستان، امروزه یا وجود ندارند یا تغییر نام دادهاند. تفاصيل المقالة -
حرية الوصول المقاله
90 - Crystallization Kinetics Study in Al87Ni10La3 Amorphous Alloy
Amir Rofigar Haghighi Akbar Heidarpour Mohsen Eshaghpour Soorani Mehdi MansouriIn this study, the crystallization behavior of melt-spun Al87Ni10La3 amorphous phase was investigated by using X-ray diffraction and non-isothermal differential thermal analysis techniques. The results demonstrated that the amorphous phase exhibited two-stage crystalliz أکثرIn this study, the crystallization behavior of melt-spun Al87Ni10La3 amorphous phase was investigated by using X-ray diffraction and non-isothermal differential thermal analysis techniques. The results demonstrated that the amorphous phase exhibited two-stage crystallization on heating, i.e., at first step the amorphous phase transforms into α-Al phase and at second step Al11La3 and Al3Ni intermetallic phases precipitate, simultaneously. The activation energies of the crystallizations of the amorphous phase were evaluated by the Kissinger equation using the peak temperature of the exothermic reactions. The values of two-step crystallization activation energies were approximately 173.7±6 and 278.4±5 kJ/mol, respectively. The Avrami index was calculated for the first and second step of crystallizations and obtained 0.9 and 3.8 respectively. This kinetics investigation indicated that in the first step of crystallization of Al87Ni10La3 alloy, the nucleation rate decreases with time, and the crystallization is governed by a three-dimensional diffusion-controlled growth, while the second stage was in interface control regime. تفاصيل المقالة -
حرية الوصول المقاله
91 - Extraction of Hemicellulose and Lignin from Sugarcane Bagasse for Biopolymer Films: Green Process
Sifiso Nkosi Krishnan KannyA hemicellulose is any of several heteropolymers , such as arabinoxylans, present along with cellulose in almost all plant cell walls. Hemicellulose has a random, amorphous structure with little strength. It is easily hydrolyzed by dilute acid or base as well as myriad أکثرA hemicellulose is any of several heteropolymers , such as arabinoxylans, present along with cellulose in almost all plant cell walls. Hemicellulose has a random, amorphous structure with little strength. It is easily hydrolyzed by dilute acid or base as well as myriad hemicellulase enzymes. In this study, lignin and hemicellulose was extracted from sugarcane bagasse using the ammonium hydrolysis process. The extraction of hemicellulose was carried out at 250C (room temperature) with 25% Ammonia Solution. The sugarcane bagasse extract was used together with starch to produce thin films. The films were characterized using Fourier transformed infrared (FTIR), X-ray diffraction (XRD), Thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The FT-IR and XRD analysis of the films confirmed the presence of hemicellulose and lignin. The TGA shows an average of 16.75% and 50.61% for lignin and hemicellulose respectively. The crystallinity index values obtained from XRD showed that film materials were amorphous and have higher values when compared with untreated SCB, due to the partial removal of hemicellulose after ammonium hydrolysis treatment. تفاصيل المقالة -
حرية الوصول المقاله
92 - The effect of saccharin on microstructure and corrosion behavior of nanocrystalline nickel thin films in alkaline solution
Behrooz Shayegh Nima ZaghianIn this study the effect of crystallite size reduction and microstructure on the electrochemical corrosion behavior of nanocrystalline nickel (NC Ni) were investigated using Tafel polarization and electrochemical impedance spectroscopy (EIS) measurements in 10 wt.% NaOH أکثرIn this study the effect of crystallite size reduction and microstructure on the electrochemical corrosion behavior of nanocrystalline nickel (NC Ni) were investigated using Tafel polarization and electrochemical impedance spectroscopy (EIS) measurements in 10 wt.% NaOH. NC Ni coatings were produced by direct current electrodeposition using chloride baths in presence and absence of saccharin as a grain refining agent. The crystallite size of NC surface coatings was calculated and analyzed by X-ray diffractometry (XRD). Field emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM) were used to study coatings microstructure. The chemical composition of NC surfaces was determined using X-ray energy dispersive spectroscopy (EDS). Our results showed Saccharin decreased the crystallite size but increased the grain size. In addition, corrosion resistance of NC Ni in presence of saccharin increased, which is ascribed to the formation of more stable and protective film. The behavior of passive film growth and corrosion were discussed. تفاصيل المقالة -
حرية الوصول المقاله
93 - Production and Characterization of Nano Crystalline Fe85Si10Ni5 Soft Magnetic Alloys by Mechanical Alloying
Arash Dezhsetan Ali Saidi Reza Ebrahimi-KahrizsangiAbstract There are various methods to produce iron based nano crystalline magnetic alloys. Among these methods, mechanical alloying is one of the most important. In this research, nano crystalline Fe85Si10Ni5 soft magnetic alloy was synthesized by mechanical alloying. أکثرAbstract There are various methods to produce iron based nano crystalline magnetic alloys. Among these methods, mechanical alloying is one of the most important. In this research, nano crystalline Fe85Si10Ni5 soft magnetic alloy was synthesized by mechanical alloying. The effect of alloying time on phase constituents and magnetic properties of the produced powders was investigated, by X-ray diffraction (XRD) and alternating gradient force magnetometer (AGFM). The XRD results showed that alloy formation started after 2 hours of milling. Further milling resulted in the reduction of the grain size and lattice parameter. After 60 hours of milling, the grain size was reduced to 8 nm. AGFM results showed that magnetic saturation and coercivity depends on the alloying time. Increasing the alloying time, causes the increase of magnetic saturation and decrease of coercivity. Abstract There are various methods to produce iron based nano crystalline magnetic alloys. Among these methods, mechanical alloying is one of the most important. In this research, nano crystalline Fe85Si10Ni5 soft magnetic alloy was synthesized by mechanical alloying. The effect of alloying time on phase constituents and magnetic properties of the produced powders was investigated, by X-ray diffraction (XRD) and alternating gradient force magnetometer (AGFM). The XRD results showed that alloy formation started after 2 hours of milling. Further milling resulted in the reduction of the grain size and lattice parameter. After 60 hours of milling, the grain size was reduced to 8 nm. AGFM results showed that magnetic saturation and coercivity depends on the alloying time. تفاصيل المقالة -
حرية الوصول المقاله
94 - Simulation of Heat Transfer and Recrystallization in Aluminum Alloy AA 6070 by TIG Welding Method
Mir Javad Mir Najd Gerami Eslam Ranjbarnodeh Mehdi FarajpourAluminum alloys have many applications in transportation industry because of their abundance, ease of production, as well as proper mechanical and physical properties. One of these alloys is obtained by combining aluminum with silicon and magnesium (Al-Mg-Si alloys). Si أکثرAluminum alloys have many applications in transportation industry because of their abundance, ease of production, as well as proper mechanical and physical properties. One of these alloys is obtained by combining aluminum with silicon and magnesium (Al-Mg-Si alloys). Since the plates of this alloy are rolled up, heat transfer and crystallization in the heat-affected zone (HAZ) is an important point in their welding. In this study, we have attempted to investigate welding-induced recrystallization in this alloy using the finite element method. For this purpose, the physics of the problem was defined and simulated using ANSYS software. In the next step, the results of theoretical (simulated) and experimental investigations were compared and the effect of current on the size of weld pool and thermal cycle of different samples was assessed. Then, through microscopic examination of different areas of the welded samples, the size of recrystallized area was measured and compared with the results of mathematical calculations. Finally, the hardness of weld zone and recrystallized area was analyzed. A temperature of 630°C and holding time of about 0.3 seconds is sufficient for recrystallization of this alloy during welding. تفاصيل المقالة -
حرية الوصول المقاله
95 - Effect of Heat Treatment on Structural and Magnetic Properties of Nanocrystalline SrFe12O19 Hexaferrite synthesized by Co-Precipitation Method
Mansoureh Ganjali Monireh Ganjali Arvin Eskandari Masoud AminzareNanocrystalline strontium hexaferrite (SrFe12O19) powders have been successfully synthesized using the facile Co-precipitation method. The ferrite precursors were achieved from mixtures of strontium and ferric chloride in an aqueous medium without any surfactant and sof أکثرNanocrystalline strontium hexaferrite (SrFe12O19) powders have been successfully synthesized using the facile Co-precipitation method. The ferrite precursors were achieved from mixtures of strontium and ferric chloride in an aqueous medium without any surfactant and soft template. The as-received powders were calcined at 800 and 1000 ˚C for 2 hours in air. The final powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), BET surface area analysis and Vibrating Sample Magnetometer (VSM). The effects of the calcination temperature on the phase composition, particle size and shape as well as the magnetic properties of the products have been investigated. The results indicated that the higher calcination temperature (1000 oC) resulted in higher particle sizes (98.1 nm), maximum saturation magnetization (60.53 emu/g), remanence value (36.23 emu/g) and less surface area (12 m2g-1). The magnetocrystalline anisotropy constant, K, calculated from the Stoner–Wohlfarth theory are increased by increasing temperature up to 15.1 (HA2/kg). تفاصيل المقالة -
حرية الوصول المقاله
96 - Effect of Heat Treatment Time on the Characteristics of Coating Formed on Nanocrystalline Finemet Foils
Sima Mirzaei Ali Jazayeri GharehbaghIn the present research, amorphous Fe73.5Si13.5B9Nb3Cu1 Finemet foils, 21-26µm in thickness and 5mm in width, were prepared by Planar Flow Casting (PFC) process. Wound cores of amorphous Finemet foils were simultaneously annealed and heat treated at 540°C for أکثرIn the present research, amorphous Fe73.5Si13.5B9Nb3Cu1 Finemet foils, 21-26µm in thickness and 5mm in width, were prepared by Planar Flow Casting (PFC) process. Wound cores of amorphous Finemet foils were simultaneously annealed and heat treated at 540°C for 60, 120 and 240 minutes in steam and air flow to form oxide insulating coating layer on both surfaces of the foils. The structure of nanocrystalline foils was examined by X-ray diffractometry (XRD). The thickness and chemical composition of the insulating coating layer were studied by Field Emission Scanning Electron Microscopy (FE-SEM), Grazing Incidence XRD (GI-XRD) and Fourier Transform Infrared Spectroscopy (FTIR) techniques. The results show that the coating thickness formed on air and wheel surfaces of the foil was in the range of 65-310 nm and these thin coating layers contain a mixture of iron, silicon, boron and niobium oxides. The study of magnetic properties in amorphous and nanocrystalline states revealed that nanocrystalline cores have superior soft magnetic properties compared with the amorphous ones. In other words, the heat treatment gives rise to a decrease in hysteresis loss and a significant increase in saturation induction and magnetic permeabilities. تفاصيل المقالة -
حرية الوصول المقاله
97 - Effect of Ni on Amorphization of Ti-Cu-Ni Ternary alloys Prepared by Mechanical alloying
Masoud Ghadiri Ali SaidiAmorphous alloys has been taken into consideration because of their unique properties and are nominated as the future engineering materials. In this research, the effect of Ni and milling time on amorphization process and thermal stability of Ti50Cu50-xNix(x=10, 15, 25 أکثرAmorphous alloys has been taken into consideration because of their unique properties and are nominated as the future engineering materials. In this research, the effect of Ni and milling time on amorphization process and thermal stability of Ti50Cu50-xNix(x=10, 15, 25 at%) alloy system were investigated. The evolution of amorphization during milling, thermal stability and subsequent heat treatment were evaluated by x-ray diffraction (XRD) and differential scanning calorimetry (DSC). The results showed that alloys reached to the highest content of amorphous phase in Ti50Cu40Ni10, Ti50Cu15Ni35 and Ti50Cu25Ni25 alloy compounds after 60, 40 and 10 hours respectively. Differential scanning calorimetry showed thermal stability of amorphous alloy, exhibiting a distinct glass transition and crystallization temperature and a wide supercooled liquid region for Ti50Cu25Ni25 powder alloy with a value about 45 k. Heating Ti50Cu25Ni25 amorphous alloy at 943 k for 10 min results in the formation of intermetallics such as CuTi and NiTi2 phases. In addition, mechanical properties of amorphous powders were studied by Vickers microhardness test. The alloy with 25 percent Ni showed The high value of hardness about 884 Hv after 40 hours milling. تفاصيل المقالة -
حرية الوصول المقاله
98 - Finite Element Modeling of Strain Rate and Grain Size Dependency in Nanocrystalline Materials
Minoo TabanfardNanocrystalline materials show a higher strain-rate sensitivity in contrast to the conventional coarse-grained materials and a different grain size dependency. To explain these phenomenon, a finite element model is constructed that considers both grain interior and grai أکثرNanocrystalline materials show a higher strain-rate sensitivity in contrast to the conventional coarse-grained materials and a different grain size dependency. To explain these phenomenon, a finite element model is constructed that considers both grain interior and grain boundary deformation of nanocrystalline materials. The model consist of several crystalline cores with different orientations and grain boundary phase. The nonlinear behavior of the nanocrystalline core is implemented by a grain size dependent crystal plasticity. The boundary phase is assumed to have the mechanical properties of quasi-amorphous material. The constitutive equations for both grains interior and boundary phase are implemented into the finite-element software Abaqus. A calibration procedure was used to tune some parameters of the model with the previously published experimental data on the nanocrystalline copper. Then the model is used to predict the material behavior in various strain rates and grain sizes. The stresses obtained from these simulations match well with the experimental data for nanocrystalline copper at different strains and strain rates. Deviation from the Hall-Petch law and inverse Hall-Petch effect are also well illustrated by the model. تفاصيل المقالة -
حرية الوصول المقاله
99 - Utilization of Microalloying with Rare Earth Elements and Hot Extrusion for Remarkable Grain Refinement and Enhancement of Mechanical Properties of as-Cast Magnesium Alloy
Hooman Abedi Massoud Emamy Hamed Mirzadeh Jafar Rassizadehghani M. Ra'ayatpourThe effects of micro-addition by rare earth (RE) elements (via cerium-based mischmetal) and hot deformation (via extrusion process) on the microstructure and mechanical properties of Mg-0.5Zn-0.5Zr alloy were studied. Optical microscopy, scanning electron microscopy (SE أکثرThe effects of micro-addition by rare earth (RE) elements (via cerium-based mischmetal) and hot deformation (via extrusion process) on the microstructure and mechanical properties of Mg-0.5Zn-0.5Zr alloy were studied. Optical microscopy, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and tensile testing were used for characterization of alloys in the as-cast and wrought conditions. It was found that the addition of 0.5 wt% RE combined with the hot extrusion process could remarkably refine the grain size from 1320 µm for the as-cast Mg-0.5Zn-0.5Zr alloy to the recrystallized grain size of 1.3 µm for the extruded Mg-0.5Zn-0.5Zr-0.5RE alloy. Compared to the as-cast counterparts, the ultimate tensile strength (UTS) and total elongation to failure were significantly enhanced by the extrusion process. Quantitatively, the UTS of ~ 300 MPa with the total elongation of ~ 18% was obtained for the extruded Mg-0.5Zn-0.5Zr-0.5RE alloy, which reveals the favorable effects of the ultra grain refinement on the enhancement of the mechanical properties of magnesium alloys. تفاصيل المقالة -
حرية الوصول المقاله
100 - Evaluation of Flow Behavior of Novel Titanium Ti-3873 Alloy Via Compressive Deformation in Two Phase α/β and Single Phase β Regions
Mahnaz Dabbaghi Maryam MorakabatiSemi-stable β-titanium (Ti-3873) Ti-3Al-8Mo-7V-3Cr alloy with excellent workability properties has been designed based on high demanded aircraft Ti-5Al-5Mo-5V-3Cr alloy according to semi-experimental d-electron approach. The aim of the present research is to investigate أکثرSemi-stable β-titanium (Ti-3873) Ti-3Al-8Mo-7V-3Cr alloy with excellent workability properties has been designed based on high demanded aircraft Ti-5Al-5Mo-5V-3Cr alloy according to semi-experimental d-electron approach. The aim of the present research is to investigate the deformation behavior of Ti-3873 alloy via warm compression test. For this purpose, compression test has been conducted in the temperature range of 650-850 °C and strain rates of 0.001,0.1 and 1, 1 s-1 at dual phase α/β and single phase β regions. The test was continued up to plastic strain of 0.7. For establishing the relationship between the microstructure and flow behavior, the initial and subsequent microstructure of the specimens after warm deformation was studied via optical and scanning electron microscopes. The microstructural evaluation and flow curves revealed that dynamic recovery and partial continuous dynamic recrystallization were the dominant restoration mechanisms. The results showed that softening has been increased in the temperature range of 800-850 °C and strain of 0.001 and 0.1 s-1 which is confirmed by the activation energy calculated from the sinus hyperbolic equation. The activation energy for dual phase α/β and single phase β regions are determines as 429 kJ/mol and 353 kJ/mol, respectively. The higher value of activation energy for α/β dual phase region is attributed to dynamic globularization of α lamellas. The preferable regions for hot workability of the alloy were achieved at the temperature range of 800-850 °C and strain rate of 0.01-0.001 s-1 corresponding to the peak efficiency of 39% in the processing map. تفاصيل المقالة -
حرية الوصول المقاله
101 - Fine Grain Formation in as Cold Worked SP700 Titanium Alloy and Its Effect on Mechanical and Superplastic Properties
Marjan Daryaban Maryam Morakabati Noshin MerajiThe aim of this research is to study the effect of fine grain structure on the mechanical and superplastic properties of cold worked SP700 alloy. Thickness reductions of 20%, 40%, and 60%. were applied during cold rolling. Then the specimens were annealed at 700°C, 750° أکثرThe aim of this research is to study the effect of fine grain structure on the mechanical and superplastic properties of cold worked SP700 alloy. Thickness reductions of 20%, 40%, and 60%. were applied during cold rolling. Then the specimens were annealed at 700°C, 750°C, and 800°C for 40 minutes. The tensile test was applied at 25, 700oC, 750°C, and 800°C with strain rates of 0.01s-1, 0.005s-1 and 0.001s-1. The SEM and OM were used to analyze the specimens' microstructures. The alloy cold rolled to 40% reduction and annealed at 700°C exhibited a maximum elongation of 1380% at a stress level of 30 MPa and a strain rate of 0.005 s-1 at 700°C. Microstructural evlauation showed that during the superplastic test, dynamic recrystallization took place. The strain rate sensitivity varied in the range of 0.32 to 0.46. Fundamental equations were also used to determine the mechanism of superplasticity. The activation energy is obtained as 385 kJ.mol-1. Results validated that the Rachinger sliding is the main superplastic mechanism in the SP700 alloy. تفاصيل المقالة -
حرية الوصول المقاله
102 - Influence of Initial Microstructure on Hot Deformation Behavior of Duplex Stainless Steels
M Pouyamanesh B Eghbali Gh. R Ebrahimi M SaadatiIn this research the effect of initial microstructure on hot deformation behavior in terms of Ferrite-to-Austenite ratios is studied. Two types of stainless steels C1 and C2 were homogenizing heat-treated and deformed under hot compression examinations at temperatures 9 أکثرIn this research the effect of initial microstructure on hot deformation behavior in terms of Ferrite-to-Austenite ratios is studied. Two types of stainless steels C1 and C2 were homogenizing heat-treated and deformed under hot compression examinations at temperatures 900ºC and 1100ºC at strain rate of 0.1s-1. The results showed that the flow stress levels of specimens are strongly related to deformation parameters and initial microstructures of steels. Moreover, during cooling from 1350ºC to the deformation temperature, flow stress level increased for both samples because of increment in austenite content. تفاصيل المقالة -
حرية الوصول المقاله
103 - Synthesis of Fe3O4/Eggshell and egg membrane Nanocomposite and Application for Adsorption of Cationic and Anionic Dyes
Naereh Besharati nina alizadehThis work is reported on the synthesis of Fe3O4/eggshell nanocomposites in the absence of any stabilizer or surfactant. Fe3O4 magnetic nanoparticles were established on the egg shell. The adsorption of Malachite green (MG) and Crystal violet (CV) as cationic dyes and Er أکثرThis work is reported on the synthesis of Fe3O4/eggshell nanocomposites in the absence of any stabilizer or surfactant. Fe3O4 magnetic nanoparticles were established on the egg shell. The adsorption of Malachite green (MG) and Crystal violet (CV) as cationic dyes and Eriochrome Black T (EBT) as an anionic dye by magnetite nanoparticles loaded egg shell (MNLES) and magnetite nanoparticles loaded egg membrane (MNLEM) were studied. FT-IR, XRD and SEM were used for specification of adsorbents. XRD pattern of MNLES and MNLEM were corresponded to pure magnetite at 2θ= 30.2o, 35.6o, 43.3o and 57.2o. FTIR showed that main peak similar magnetite in 580, 1620 and 3407cm-1. SEM pictures showed that Fe3O4 nanoparticles in nm size loaded on natural adsorbents. Adsorbents dose, pH and contact time as parameters that have effect on dyes removal were investigated. Pseudo-first order, pseudo-second order, intraparticle diffusion and Elovich models were used for study of kinetic of adsorption. The sorption of the MG, EBT, CV on the MNLEM were pseudo second-order model. The sorption of the MG and EBT on MNLES were described by Elovich and pseudo second-order model. Value of qmax from the Langmuir model for adsorption of CV, EBT and MG were 61.72, 21.69 and 38.31mg g -1 for MNLEM and qmax for adsorption of EBT, MG on the MNLES was 40.0 and 25.12mg g -1. It was found MNLES and MNLEM can be used as efficient adsorbents for removal of EBT more than cationic dyes (MG, CV). تفاصيل المقالة -
حرية الوصول المقاله
104 - Low temperature hydrothermal synthesis, evaluation of band gap energies and catalytic performance for Biginelli reactions of Sr2-xAxNb2O7+δ (A=Eu3+ and Nd3+) (x = 0.01 and 0.05) nanomaterials
shahin khademinia mahdi behzadNano powders Eu3+ and Nd3+ - doped Sr2Nb2O7 were prepared by a low temperature hydrothermal method at 120 ºC for 48 h followed by annealing at 400 ᵒC for 3 h among Sr(NO3)2 and Nb2O5, Eu2O3 and Nd2O3 raw materials at stoichiometric 1:1 Sr:Nb molar ratio. Characterizati أکثرNano powders Eu3+ and Nd3+ - doped Sr2Nb2O7 were prepared by a low temperature hydrothermal method at 120 ºC for 48 h followed by annealing at 400 ᵒC for 3 h among Sr(NO3)2 and Nb2O5, Eu2O3 and Nd2O3 raw materials at stoichiometric 1:1 Sr:Nb molar ratio. Characterization of the synthesized materials was performed by X-ray powder diffraction (XRPD) technique. FullProf program employing profile matching with constant scale factors was employed for structural analysis. The results showed that the patterns had a main Sr2Nb2O7 orthorhombic crystal structure with space group Cmc21. FESEM images showed that the synthesized nanomaterials had flower morphologies. Ultraviolet-visible spectra analysis showed that the synthesized Eu3+ and Nd3+ - doped Sr2Nb2O7 nanomaterials had light absorption in the ultraviolet light region. The direct optical band gap energies obtained from UV-Vis absorption spectra were 3.45, 3.50 and 3.80 eV for pure Sr2Nb2O7, S2 and S4, respectively. The catalytic activity of the obtained materials in the one-pot synthesis of the heterocyclic compounds 3,4-dihydropyrimidin-2(1H)-ones (DHPMs) in Biginelli reaction is investigated. The optimized 0.03 g of the catalyst, 95 ºC reaction temperature, and 60 min reaction time are used for the other Biginelli reactions in this work. تفاصيل المقالة -
حرية الوصول المقاله
105 - Effect of growth time on ZnO thin films prepared by low-temperature chemical bath deposition on PS substrate
Reza Shabannia Nima NaderiZnO thin films were successfully synthesized on a porous silicon (PS) substrate by chemical bath deposition method. X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and photoluminescence (PL) analyses were carried out to investigate the eff أکثرZnO thin films were successfully synthesized on a porous silicon (PS) substrate by chemical bath deposition method. X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and photoluminescence (PL) analyses were carried out to investigate the effect of growth duration (3, 4, 5, and 6 h) on the optical and structural properties of the aligned ZnO nanorods. The small FWHM and stronger diffraction intensity of growth times of 5 h mean the better crystal quality of ZnO thin films compared to others. The grain size of the ZnO thin films gradually increased with increased the growth time. The FESEM images show that the thickness of ZnO thin films increased with increase of the growth time. Photoluminescence measurements showed that there was a sharp and highly intense UV emission peak when growth time was 5 h. The structural and optical investigations revealed that the ZnO thin films grown on the PS substrate with growth time of 5 h had high structural and optical quality. تفاصيل المقالة -
حرية الوصول المقاله
106 - The effect of acid/cellulose ratio on the quality of Cellulose Nanocrystal (CNC) suspension
Nasrin Shahmiri Nahid Hassanzadeh Nemati Ahmad Ramazani Saadatabadi Massoud SeifiCellulose nanocrystals are promising materials for application in biomedicine, pharmaceutical and food industry. There are various methods for CNC synthesis, but acid hydrolysis is the most common one. The optimization of acid hydrolysis process is still in progress. In أکثرCellulose nanocrystals are promising materials for application in biomedicine, pharmaceutical and food industry. There are various methods for CNC synthesis, but acid hydrolysis is the most common one. The optimization of acid hydrolysis process is still in progress. In the present study, different CNC suspensions were prepared to find out the more efficient acid ratio for CNC production. Whatman #1 filter paper was hydrolyzed via 64 wt% sulfuric acid at acid-to-paper ratio of 10:1 mL/g, 20:1 mL/g, 30:1 mL/g, and 40:1 mL/g. The synthesized CNCs were characterized by DLS, ELS and AFM. The suspensions with acid/cellulose ratio of 20:1 mL/g & 30:1 mL/g resulted in CNCs with more negative surface charge and uniform size. They also represented chiral nematic phase and regular self-organization after layer by layer deposition. It was found that the higher acid-to-paper ratio does not necessarily produce the high quality CNCs. Since the suspension that was prepared at acid/cellulose ratio of 40:1 mL/g had lower negative charge. The size and surface charge of CNCs are highly dependent to acid hydrolysis parameters and ultimately affect their behavior in nano-composites. In spite of many published papers around CNC synthesis by acid hydrolysis, there are still some details that must be addressed and investigated more to prepare the most efficient and applicable CNCs. تفاصيل المقالة -
حرية الوصول المقاله
107 - Removal of Crystal violet Dye from Aqueous Solution Using Surfactant Modified NiFe2O4 as Nanoadsorbent; Isotherms, Thermodynamics and kinetics Studies
Nina Alizadeh Mohammad MahjoubThe removal of crystal violet from aqueous solution by NiFe2O4 magnetic nanoparticles treated with sodium dodecyl sulfate was investigated. The modified magnetic nanoparticles were prepared by chemical reaction of a mixture of Ni+2 and Fe+3 ions mixture in aqueous solut أکثرThe removal of crystal violet from aqueous solution by NiFe2O4 magnetic nanoparticles treated with sodium dodecyl sulfate was investigated. The modified magnetic nanoparticles were prepared by chemical reaction of a mixture of Ni+2 and Fe+3 ions mixture in aqueous solution at the presence of ammonia and then sodium dodecyl sulfate was utilized as an ionic surfactant to modified the obtained magnetic nanoparticles. The morphologies of synthesized magnetic nanoparticles was characterized by electron microscopy techniques. The X–ray diffraction results confirmed the formation of magnetic nanoparticles with face centred cubic structure and the crystallite size was found to be 19 nm. The Fourier transform infrared spectrums confirmed the coating of sodium dodecyl sulfate on synthesized magnetic nanoparticles. The effects of different parameters, such as pH, initial concentration of dye and contact time were studied on the adsorption of crystal violet onto modified magnetic nanoparticles. The equilibrium data of dye adsorption were well fitted to the Freundlich adsorption isotherm. Adsorption kinetic was accommodated by a pseudo–second–order model and the results, obtained from Boyd plot indicated that the crystal violet adsorption onto modified magnetic nanoparticles was controlled by film diffusion. Thermodynamic parameters, such as changes in Gibbs free energy, enthalpy, and entropy were also determined. The calculated activation energy suggested physical adsorption of dye onto synthesized magnetic nanoparticles. تفاصيل المقالة -
حرية الوصول المقاله
108 - Low temperature hydrothermal synthesis, evaluation of band gap energies and catalytic performance for Biginelli reactions of Sr2-xAxNb2O7+δ (A=Eu3+ and Nd3+) (x = 0.01 and 0.05) nanomaterials
shahin khademinia Mahdi BehzadNano powders Eu3+ and Nd3+ - doped Sr2Nb2O7 were prepared by a low temperature hydrothermalmethod at 120 ºC for 48 h followed by annealing at 400 ᵒC for 3 h among Sr(NO3)2and Nb2O5, Eu2O3 and Nd2O3 raw materials at stoichiometric 1:1 Sr:Nb molar ratio. Characteriza أکثرNano powders Eu3+ and Nd3+ - doped Sr2Nb2O7 were prepared by a low temperature hydrothermalmethod at 120 ºC for 48 h followed by annealing at 400 ᵒC for 3 h among Sr(NO3)2and Nb2O5, Eu2O3 and Nd2O3 raw materials at stoichiometric 1:1 Sr:Nb molar ratio. Characterizationof the synthesized materials was performed by X-ray powder diffraction (XRPD)technique. FullProf program employing profile matching with constant scale factors was employedfor structural analysis. The results showed that the patterns had a main Sr2Nb2O7 orthorhombiccrystal structure with space group . FESEM images showed that the synthesizednanomaterials had flower morphologies. Ultraviolet-visible spectra analysis showed that thesynthesized Eu3+ and Nd3+ - doped Sr2Nb2O7 nanomaterials had light absorption in the ultravioletlight region. The direct optical band gap energies obtained from UV-Vis absorption spectrawere 3.45, 3.50 and 3.80 eV for pure Sr2Nb2O7, S2 and S4, respectively. The catalytic activity ofthe obtained materials in the one-pot synthesis of the heterocyclic compounds 3,4-dihydropyrimidin-2(1H)-ones (DHPMs) in Biginelli reaction is investigated. The optimized 0.03 g of thecatalyst, 95 ºC reaction temperature, and 60 min reaction time are used for the other Biginellireactions in this work. تفاصيل المقالة -
حرية الوصول المقاله
109 - Effect of growth time on ZnO thin films prepared by low temperature chemical bath deposition on PS substrate
Reza Shabannia Nima NaderiZnO thin films were successfully synthesized on a porous silicon (PS) substrate by chemical bath deposition method. X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and photoluminescence (PL) analyses were carried out to investigate the effe أکثرZnO thin films were successfully synthesized on a porous silicon (PS) substrate by chemical bath deposition method. X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and photoluminescence (PL) analyses were carried out to investigate the effect of growth duration (3, 4, 5, and 6 h) on the optical and structural properties of the aligned ZnO nanorods. The small FWHM and stronger diffraction intensity of growth times of 5 h mean the better crystal quality of ZnO thin films compared to others. The grain size of the ZnO thin films gradually increased with increased the growth time. The FESEM images show that the thickness of ZnO thin films increased with increase of the growth time. Photoluminescence measurements showed that there was a sharp and highly intense UV emission peak when growth time was 5 h. The structural and optical investigations revealed that the ZnO thin films grown on the PS substrate with growth time of 5 h had high structural and optical quality. تفاصيل المقالة -
حرية الوصول المقاله
110 - Synthesis of Fe3O4/Eggshell and egg membrane Nanocomposite and Application for Adsorption of Cationic and Anionic Dyes
Naereh Besharati Nina AlizadehThis work is reported on the synthesis of Fe3O4/eggshell nanocomposites in the absence of anystabilizer or surfactant. Fe3O4 magnetic nanoparticles were established on the egg shell. The adsorptionof Malachite green (MG) and Crystal violet (CV) as cationic dyes and Erio أکثرThis work is reported on the synthesis of Fe3O4/eggshell nanocomposites in the absence of anystabilizer or surfactant. Fe3O4 magnetic nanoparticles were established on the egg shell. The adsorptionof Malachite green (MG) and Crystal violet (CV) as cationic dyes and Eriochrome Black T (EBT) as ananionic dye by magnetite nanoparticles loaded egg shell (MNLES) and magnetite nanoparticles loadedegg membrane (MNLEM) were studied. FT-IR, XRD and SEM were used for specification of adsorbents.XRD pattern of MNLES and MNLEM were corresponded to pure magnetite at 2θ= 30.2o, 35.6o, 43.3o and57.2o. FTIR showed that main peak similar magnetite in 580, 1620 and 3407cm-1. SEM pictures showedthat Fe3O4 nanoparticles in nm size loaded on natural adsorbents. Adsorbents dose, pH and contacttime as parameters that have an effect on dye removal were investigated. Pseudo-first order, pseudosecondorder, intraparticle diffusion and Elovich models were used for study of kinetic of adsorption. Thesorption of the MG, EBT, CV on the MNLEM were pseudo second-order model. The sorption of the MGand EBT on MNLES were described by Elovich and pseudo second-order model. Value of qmax from theLangmuir model for adsorption of CV, EBT and MG were 61.72, 21.69 and 38.31mg g -1 for MNLEM andqmax for adsorption of EBT, MG on the MNLES was 40.0 and 25.12mg g -1. It was found MNLES and MNLEMcan be used as efficient adsorbents for removal of EBT more than cationic dyes (MG, CV). تفاصيل المقالة -
حرية الوصول المقاله
111 - Assessment of Photonic Crystal Fibers for Dispersion Factor of Different Structure
Mozhdeh KaramifardPhotonic crystal fibers (PCFs) are widely used in optical industries and telecommunication systems as a low dispersion and structural losses with low nonlinear coefficient. Photonic crystals are media where their refractive index distribution function is periodic or non أکثرPhotonic crystal fibers (PCFs) are widely used in optical industries and telecommunication systems as a low dispersion and structural losses with low nonlinear coefficient. Photonic crystals are media where their refractive index distribution function is periodic or non-periodic. A manifest property of photon crystals is the presence of a band-gap in the signal transmission spectrum. Electromagnetic detection with frequency range in the band range is not prohibited. Hence, the electromagnetic waves with a frequency range in the band-gap cannot be propagated. In this paper, the dispersion property of silica core photonic crystal fibers is analyzed for three and six-ring air hole structures. It is illustrated that the six-ring air hole structure shows satisfactory results in our design. Also, considering the holes filled with concentrated silica with fluorine materials, GeO2, P2O5, and B2O3 instead of air holes, it has been shown that the diffusion properties will have significant differences. The results obtained from simulations are shown by comparing with pure silica crystal. تفاصيل المقالة -
حرية الوصول المقاله
112 - Improvement of Quality Specifications of Light-Emitting Diodes based on the Photonic Crystals
Ali KianIn this paper, a new structure of Light-Emitting Diodes (LEDs) based on the usage of Gallium Nitride (GaN) semiconductors has been proposed in which, in order to improve the efficiency of the output light, a reflective layer along with two Photonic Crystal (PC) layers h أکثرIn this paper, a new structure of Light-Emitting Diodes (LEDs) based on the usage of Gallium Nitride (GaN) semiconductors has been proposed in which, in order to improve the efficiency of the output light, a reflective layer along with two Photonic Crystal (PC) layers have been employed. The applied changes and their optimization illustrated increase in output light efficiency as much as 133% with respect to a typical LED. تفاصيل المقالة -
حرية الوصول المقاله
113 - Characterization and Investigation of Grain Selection in Spiral Grain Selectors during Casting Single-Crystal Turbine Blades
Hassan Gheisari Ebrahim KaramianManufactured single crystal components using Ni-base super alloys are routinely used in the hot sections of aero engines and industrial gas turbines due to their outstanding high temperature strength, toughness and resistance to degradation in corrosive and oxidative en أکثرManufactured single crystal components using Ni-base super alloys are routinely used in the hot sections of aero engines and industrial gas turbines due to their outstanding high temperature strength, toughness and resistance to degradation in corrosive and oxidative environments. To control the quality of the single crystal turbine blades, particular attention has been paid to grain selection, which is used to obtain the single crystal morphology from a plethora of columnar grains. For this purpose, different designs of grain selectors are employed and the most common type is the spiral grain selector. A typical spiral grain selector includes a starter block and a spiral (helix) located above. It has been found that the grains with orientation well aligned to the thermal gradient survive in the starter block by competitive grain growth while the selection of the single crystal grain occurs in the spiral part. In the present study, 2Dspiral selectors with different geometries were designed and produced using a state-of-the-art Bridgeman Directional Solidification casting furnace to investigate the competitive growth during grain selection in 2d grain selectors. The principal advantage of using a 2-Dselector is to facilitate the wax injection process in investment casting by enabling significant degree of automation. The directional solidification process for obtaining single crystal component for Nickel Super alloys based on the competitive growth in 2D and 3D single crystal grain selector was experimentally investigated for various geometries. Transverse sections of the grain selectors using optical and EBSD microscopy techniques were observed to understand the competitive grain growth process. تفاصيل المقالة -
حرية الوصول المقاله
114 - An Investigation on Formability and Crystallographic Texture in Novel Magnesium Alloys
Pnina Ari-Gur Andreas Quojo Quainoo Shubram Subramanyam Ashkan Razania Sven C. Vogel Wei GaoMagnesium alloys offer many advantages. They offer the very low density and good strength. They also offer good damping properties. One of the industries where reducing component weight in the automotive industry. That makes the magnesium alloys good candidates for thes أکثرMagnesium alloys offer many advantages. They offer the very low density and good strength. They also offer good damping properties. One of the industries where reducing component weight in the automotive industry. That makes the magnesium alloys good candidates for these applications. Reduced weight of an automobile means also lower fuel consumption. The hexagonal closed packed structure of magnesium lends itself to strong mechanical anisotropy. In the current work, neutron diffraction was used to study the crystallographic texture developed in novel magnesium alloys during cold rolling operations. The texture was compared with that developed in the commercial AZ-31 magnesium alloy. Tests were run at the High-Pressure-Preferred-Orientation (HIPPO) beamline at Los Alamos National Lab. The texture was then analyzed using pole figures, created using the Material Analysis Using Diffraction (MAUD) software. تفاصيل المقالة -
حرية الوصول المقاله
115 - مدلسازی ترانسفورمرهای پالسی با هستههای نانو بلوری
امیر بکتاش ابوالفضل واحدیامروزه هستههای نواری مدور نانو بلوری بهواسطه ویژگیهای مغناطیسی مطلوبی که دارند به طور گستردهای در ترانسفورمرهای پالسی و فرکانس بالا مورد استفاده قرار میگیرند. ساختار حلزونی این هستهها بر روی نحوه توزیع شار درون آن تأثیر گذاشته و باعث پیچیدگی زیاد تحلیل مغناطیسی ا أکثرامروزه هستههای نواری مدور نانو بلوری بهواسطه ویژگیهای مغناطیسی مطلوبی که دارند به طور گستردهای در ترانسفورمرهای پالسی و فرکانس بالا مورد استفاده قرار میگیرند. ساختار حلزونی این هستهها بر روی نحوه توزیع شار درون آن تأثیر گذاشته و باعث پیچیدگی زیاد تحلیل مغناطیسی این هستهها شده است. در این مقاله با استفاده از روش شبکههای رلوکتانسی یک مدل برای این هستهها ارائه شده است. این مدل قادر به تعیین شار در نقاط مختلف هسته میباشد. ویژگی غیرخطی مغناطیسی هسته نیز با استفاده از یک مدل پسماند در مدل هسته گنجانده شده که با استفاده از آن به آسانی میتوان تلفات مغناطیسی هسته را معلوم نمود. سادگی پیادهسازی مدل از ویژگیهای مثبت آن میباشد. نتایج شبیهسازی مدل با استفاده از نرمافزار اجزاء محدود و همچنین تستهای عملی بررسی شدهاند. مقایسه نتایج نشان میدهند که روش ارائه شده علاوه بر سادگی دارای دقت مطلوب بوده و سرعت همگرایی آن در شبیهسازی نیز بالا است. تفاصيل المقالة -
حرية الوصول المقاله
116 - اصلاح ساختار فیبرهای فوتونیک کریستال سیلیکا بمنظور ساده سازی فرآیند ساخت آنها
اشکان قنبری مهران نیکودر این تحقیق، ساختاری جدید از فیبرهای فوتونیک کریستال پیشنهاد خواهد شد، که در آنها به جای استفاده از حفرههای هوا در ناحیه پوسته فیبر، از میلههای سیلیکای تغلیط شده با فلورین 2% به منظور کاهش مشکلات مرتبط با تغییر شکل حفرههای هوا در فرآیند ساخت فیبرهای فوتونیک کریستال أکثردر این تحقیق، ساختاری جدید از فیبرهای فوتونیک کریستال پیشنهاد خواهد شد، که در آنها به جای استفاده از حفرههای هوا در ناحیه پوسته فیبر، از میلههای سیلیکای تغلیط شده با فلورین 2% به منظور کاهش مشکلات مرتبط با تغییر شکل حفرههای هوا در فرآیند ساخت فیبرهای فوتونیک کریستال استفاده خواهد شد. همچنین در ادامه، تعدادی از خواص انتشاری فیبر فوتونیک کریستال پیشنهاد شده با یک فیبر فوتونیک کریستال معمولی سیلیکا همانند فرکانس نرمالیزه، ضریب شکست موثر، پاشندگی کل و پاشندگیهای مراتب بالاتر(2 و 3) مورد تجزیه و تحلیل و مقایسه قرار خواهند گرفت. نهایتاٌ مشخص خواهد شد که ساختار جدید فیبر فوتونیک کریستال از لحاظ استفاده در فرآیند ساخت بسیار سادهتر از فیبر فوتونیک کریستال سیلیکای معمولی میباشند و از لحاظ انتشار سالیتونهای فمتوثانیه در شرایط مناسبی قرار ندارد. همچنین نشان داده خواهد شد، شرایط فیبر کریستال نوری سیلیکا جهت انتشار سالیتونهای فمتوثانیه به مراتب ایده آلتر نسبت به ساختار جدید است. تفاصيل المقالة -
حرية الوصول المقاله
117 - A favourable ultrasound-assisted method for the combinatorial synthesis of 2,3-dihydroquinazolin-4(1H)-ones via CoAl2O4 spinel nanocrystal as an efficient catalyst
Javad Safaei-Ghomi Rahele TeymuriMesoporous CoAl2O4 spinel nanocrystals ( nano-CoAl2O4 ) were synthesized and fully characterized by X- ray diffraction patterns (XRD), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), DLS (dynamic li أکثرMesoporous CoAl2O4 spinel nanocrystals ( nano-CoAl2O4 ) were synthesized and fully characterized by X- ray diffraction patterns (XRD), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), DLS (dynamic light scattering) and FT-IR. The nanocrystals promoted the preparation of quinazolinones via the one-pot, three component condensation reaction of benzaldehydes, isatoic anhydride, primary aromatic amine or ammonium acetate at 45°C under ultrasound irradiation. Experimental simplicity, great yields in concise times, the retrievability of the nanocrystals and performing the sonochemical methodology as an effective way in synthetic chemistry for the preparation of medicinally privileged heterocyclic molecules are some of the substantial features of this method. The present catalytic process is applicable to an extensive diversity of substrates for the preparation of a variety-oriented library of dihydroquinazolinones. The feasibility of doing one-pot synthesis under ultrasonic irradiation with a heterogeneous nanocrystal could improve the reaction rates and shorten the reaction times. تفاصيل المقالة -
حرية الوصول المقاله
118 - Improving methodology for the preparation of highly substituted imidazoles using nano-MgAl2O4 as catalyst under microwave irradiation
Javad Safari Soheila Gandomi-Ravandi Zahra AkbariAn efficient synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles by one-step condensation of an aldehyde, benzil, ammonium acetate and primary amine in the presence of nanocrystalline magnesium aluminate under microwave irradiation is described. Th أکثرAn efficient synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles by one-step condensation of an aldehyde, benzil, ammonium acetate and primary amine in the presence of nanocrystalline magnesium aluminate under microwave irradiation is described. The advantages of this catalyst are including simple work-up, low cost and reusability. Compared with conventional methods, the main advantages of the present procedure are its being a green method, its milder conditions, necessary shorter reaction time, and its higher yields and its selectivity. The structures of products were characterized by 1H NMR, 13C NMR, IR, elemental analyses, MS and UV spectral data. Their melting points were compared with literature report. تفاصيل المقالة -
حرية الوصول المقاله
119 - Nanocrystalline TiO2 as an efficient and reusable catalyst for the one-pot synthesis of polyhydroquinolien derivatives via Hantzsch reaction
Farhad Shirini Seyyed Vahid Atghia Meysam Alipour KhoshdelAn efficient synthesis of polyhydroquinoline derivatives was reported via four-component coupling reactions of aldehydes, 1,3-dicarbonyl ketones (dimedone or 1,3-cyclohexanedione), ethyl acetoacetate or methyl acetoacetate and ammonium acetate in the presence of a catal أکثرAn efficient synthesis of polyhydroquinoline derivatives was reported via four-component coupling reactions of aldehydes, 1,3-dicarbonyl ketones (dimedone or 1,3-cyclohexanedione), ethyl acetoacetate or methyl acetoacetate and ammonium acetate in the presence of a catalytic amount of nanocrystalline TiO2 under solvent free conditions. The reported method is mild, rapid and has the advantages such as heterogeneous catalysis, simple work-up procedure, recyclability of the catalyst and purification of products without chromatographic methods. تفاصيل المقالة -
حرية الوصول المقاله
120 - Applications of SEM-EDAX method in study of Baba-Ali & Galali iron ore, west of Hamedan
Godratollah Rostami Paydar Mohammad Lotfi Majid Ghaderi Mansor Vossoughi-Abedini Azadeh AmiriBaba-Ali and Galali iron deposits are located west of Hamadan, within the Sanandaj-Sirjan geo-structural zone. Mineralogy and crystal-chemistry of the ore bodies using 57 analyses on the magnetite iron ore by SEM-EDAX method lead to some interesting results. Detecting t أکثرBaba-Ali and Galali iron deposits are located west of Hamadan, within the Sanandaj-Sirjan geo-structural zone. Mineralogy and crystal-chemistry of the ore bodies using 57 analyses on the magnetite iron ore by SEM-EDAX method lead to some interesting results. Detecting the concentration of some trace elements such as V, Co, Ni, Cu, Cr, Ti, Au, PGE (Platinum Group Elements) and some impurities of S and P in the ore bodies indicates that only primary pyrites have concentrations of Pt. Other generations of pyrite and magnetite are depleted in these trace elements. The late stage of hydrothermal fluids that leads to mineralization of pyrite in calcite-quartz veins is important for Au mineralization and therefore pyrite is the best carrier for Au. Detection of abundant phlogopite crystals and trace element concentration patterns in the Galali iron ore has strengthened the acceptance of volcanogenic magnesium skarn type hypothesis. تفاصيل المقالة -
حرية الوصول المقاله
121 - Performance enhancement for crystallization unit of a sugar plant using genetic algorithm technique
P C Tewari Rajiv Khanduja Mahesh GuptaThis paper deals with the performance enhancement for crystallization unit of a sugar plant using genetic algorithm. The crystallization unit of a sugar industry has three main subsystems arranged in series. Considering exponential distribution for the probable failures أکثرThis paper deals with the performance enhancement for crystallization unit of a sugar plant using genetic algorithm. The crystallization unit of a sugar industry has three main subsystems arranged in series. Considering exponential distribution for the probable failures and repairs, the mathematical formulation of the problem is done using probabilistic approach, and differential equations are developed on the basis of Markov birth-death process. These equations are then solved using normalizing conditions so as to determine the steady-state availability of the crystallization unit. The performance of each subsystem of crystallization unit in a sugar plant has also been optimized using genetic algorithm. Thus, the findings of the present paper will be highly useful to the plant management for the timely execution of proper maintenance decisions and, hence, to enhance the system performance. تفاصيل المقالة -
حرية الوصول المقاله
122 - Mathematical modeling and fuzzy availability analysis for serial processes in the crystallization system of a sugar plant
Anil Kr. Aggarwal Sanjeev Kumar Vikram SinghThe binary states, i.e., success or failed state assumptions used in conventional reliability are inappropriate for reliability analysis of complex industrial systems due to lack of sufficient probabilistic information. For large complex systems, the uncertainty of أکثرThe binary states, i.e., success or failed state assumptions used in conventional reliability are inappropriate for reliability analysis of complex industrial systems due to lack of sufficient probabilistic information. For large complex systems, the uncertainty of each individual parameter enhances the uncertainty of the system reliability. In this paper, the concept of fuzzy reliability has been used for reliability analysis of the system, and the effect of coverage factor, failure and repair rates of subsystems on fuzzy availability for fault-tolerant crystallization system of sugar plant is analyzed. Mathematical modeling of the system is carried out using the mnemonic rule to derive Chapman–Kolmogorov differential equations. These governing differential equations are solved with Runge–Kutta fourth-order method. تفاصيل المقالة -
حرية الوصول المقاله
123 - بررسی ویژگی ساختاری زئولیت 5-ZSM با مقدار سیلیکای متوسط تهیه شده با اتانول
محدثه نظری فریدون یاریپورقالبها نقش مهمی را در تبلور زئولیتها ایفا می کنند. ترکیب های آمونیمی رایجترین الگوهای مورداستفاده در تهیه زئولیت 5-ZSM هستند. که به دلیل قیمت، سمیت و خورندگی زیاد میتوانند مشکل های فراوانی را در مقیاس بالا ایجاد کنند. در پژوهش حاضر امکانپذیری تولید 5-ZSM با سیلی أکثرقالبها نقش مهمی را در تبلور زئولیتها ایفا می کنند. ترکیب های آمونیمی رایجترین الگوهای مورداستفاده در تهیه زئولیت 5-ZSM هستند. که به دلیل قیمت، سمیت و خورندگی زیاد میتوانند مشکل های فراوانی را در مقیاس بالا ایجاد کنند. در پژوهش حاضر امکانپذیری تولید 5-ZSM با سیلیکای متوسط با اتانول در دم فشار همزن دار 5 لیتری (rpm 450) و با منابع آلومینا و سیلیکا ارزانقیمت و در دسترس بررسی شد. به کمک پراش پرتو ایکس (XRD)، طیف شناسی فروسرخ تبدیل فوریه (FTIR) ، میکروسکوپ الکترونی پویشی گسیل میدانی (FE-SEM)، طیفشناسی تفکیک انرژی (EDS)، فلورسانس پرتو ایکس (XRF)، تجزیه وزنسنجی گرمایی (TGA) و روش BET، اثر عامل های موثر بر ویژگی های ساختاری زئولیت بررسی شد. نتیجه ها نشان می دهد که کوچک بودن اتانول و پیوند ضعیف آن با گروههای انتهایی Si-OH در آنیونهای سیلیکات، مدت بلورسازی و حساسیت ساختار به عامل های سنتزی را افزایش میدهد. با این حال، تنظیم مناسب این عامل ها، امکان تهیه 5-ZSM با سیلیکا متوسط را با خلوص، بلورینگی و سطح ویژه بالا فراهم ساخت. نسبتهای بالای OH-/SiO2 در سامانه، با افزایش سرعت هستهزایی و کاهش رشد بلور، منجر به کاهش نسبت ابعادی Lc/La در بلور شد. همچنین، افزایش میزان Si/Al رشد سینتیکی بلور را در جهت b تقویت کرد و موجب پدیدارشدن بلورهای دوقلوی ششضلعی شد. در پایان، نسبت OH-/SiO2 برابر با 0/15 و مدت تبلور 40 ساعت، به عنوان مناسبترین شرایط برای تهیه 5-ZSM خالص با SiO2/Al2O3 برابر با 50، بازدهی بالای 90 %، بلورینگی نسبی 100 % و سطح ویژه 1-443m2gانتخاب شد. تفاصيل المقالة -
حرية الوصول المقاله
124 - سنتز نانوساختارهای هیدروکسید لایهای دوگانه برای جذب رنگ بلور ویولت از محلولهای آبی
احمد رئیسی وانانی سعید اسدپور نرگس سرمست معصومه کوراوندوجود رنگ بلور ویولت در پساب صنایع متفاوت، افزون بر آلودگی محیطزیست، میتواند موجب بروز بیماریهای متفاوتی در انسان و سایر موجودات شود. براین پایه، پژوهش در زمینه حذف و یا تخریب این آلاینده لازم به نظر میرسد. در پژوهش حاضر، کارایی هیدروکسیدهای لایه ای دوگانه اصلاحشده أکثروجود رنگ بلور ویولت در پساب صنایع متفاوت، افزون بر آلودگی محیطزیست، میتواند موجب بروز بیماریهای متفاوتی در انسان و سایر موجودات شود. براین پایه، پژوهش در زمینه حذف و یا تخریب این آلاینده لازم به نظر میرسد. در پژوهش حاضر، کارایی هیدروکسیدهای لایه ای دوگانه اصلاحشده با سدیم دودسیل سولفات (LDH/SDS) بهعنوان جاذب در حـذف این آلاینده مطالعه شد. پس از سنتز جاذب و شناسایی آن با روش های پراش پرتو ایکس (XRD)، طیف سنجی فروسرخ تبدیل فوریه (FTIR) و میکروسکوپی الکترونی روبشی (SEM)، تـأثیر عامل هایی مانند pH، زمـان تماس و غلظت اولیه آلاینده با استفاده از طراحی آزمایش بررسی شد. برای یافتن بهترین مدل هم دمای دادههای جذب، معادله های لانگمویر، فروندلیچ و تمکین ارزیابی شدند. برازش دادهها با مدلهای سینتیکی شبه درجه اول، شبه درجه دوم و نفوذ بینذرهای صورت گرفت و پس از استخراج عامل های سینتیکی، بهترین مدل سینتیکی معرفی شد. نتیجه های بهدستآمده از طراحی آزمایش و تحلیل آماری آنها، اعتبار معادله درجه دوم بهدستآمده را تأیید کرد. بررسی دادهها با استفاده از مدلهای هم دما سینتیکی نشان داد جذب بلور ویولت بر جاذب (LDH/SDS) از مدل هم دما لانگمویر و مدل سینتیکی شبه درجـه دوم پیروی میکند. تفاصيل المقالة -
حرية الوصول المقاله
125 - تولید پیوسته و کنترلشده نانوذرههای دگزامتازون در یک سامانه میکروسیالی
پیام زاهدی مریم طباطبایی مرتضی فتحی پور امین سهرابیدر این کار پژوهشی، تولید پیوسته نانوذرههای داروی دگزامتازون در یک سامانه میکروسیالی به روش نانورسوبدهی بهمنظور کنترل اندازه ذرهها، حفظ ساختار فیزیکی آنها و بالابردن کارایی این داروی آبگریز در محیطهای فیزیولوژیکی است. ابتدا، به منظور ساخت تراشه میکروسیال، کانالها أکثردر این کار پژوهشی، تولید پیوسته نانوذرههای داروی دگزامتازون در یک سامانه میکروسیالی به روش نانورسوبدهی بهمنظور کنترل اندازه ذرهها، حفظ ساختار فیزیکی آنها و بالابردن کارایی این داروی آبگریز در محیطهای فیزیولوژیکی است. ابتدا، به منظور ساخت تراشه میکروسیال، کانالهای میکرونی با طول cm 1، عرض µm 200 و عمق µm 50 در قطعهای از جنس پلیدیمتیل سیلوکسان (PDMS) بهوسیله نقشنگاری نرم با استفاده از پرتو فرابنفش ایجاد و سپس، قابلیت برقراری جریان آرام سیال در آن بررسی شد. عامل‎های موثر در تولید بهینه نانوذرههای دارو به کمک طراحی آزمایش تعیین شد. مقادیر بهینه برای غلظت محلول دارو، غلظت ماده سطح‎فعال، سرعت جریان محلول دارو و سرعت جریان ضدحلال به ترتیب برابر 15میلی‎گرم در میلی‎لیتر، 1 میلی‎گرم در میلی‎لیتر، 5/4 میلی‎لیتر بر ساعت و 8 میلی‎لیتر بر ساعت به‎دست آمد که برپایه این مقادیر اندازه ذرههای محاسبه شده از طراحی آزمایش برابر با 20 ± 590 نانومتر و به-دست آمده از تجربی برابر 20 ± 500 نانومتر شد. در ادامه، نتایج آزمون پراکندگی نور پویا (DLS) حاکی از توزیع باریک اندازه نانوذرههای دگزامتازون ساخته شده با تراشه میکروسیال است. همچنین، آزمونهای میکروسکوپ الکترونی روبشی (SEM)، گرماسنجی پویشی تفاضلی (DSC) و پراش پرتو ایکس (XRD) نشان میدهند که استفاده از سامانه میکروسیال بر بلورینگی نانوذرههای دارو تاثیری نمیگذارد و پس از فرایند در ساختار دارو تغییر چندانی ایجاد نمیشود. در نهایت، نمونه نانوذرههای دگزامتازون تولیدشده با سامانه میکروسیال مقدار حلالیت دارویی حدود هشت برابر در مقایسه با نمونه پودر تجاری را نشان میدهد. تفاصيل المقالة -
حرية الوصول المقاله
126 - Characterization of Oxide Film Formed on Ck45 Steel by Plasma Electrolytic Oxidation Method
S. Abuali Galedari م. موسوی خوئیPlasma electrolytic oxidation (PEO) is the new, environmentally and cost-effective method for coating the metals. This method vastly has been studied for coating Aluminum, Titanium and Magnesium and their alloys and recently for steel. In present study, Ck45 steel sampl أکثرPlasma electrolytic oxidation (PEO) is the new, environmentally and cost-effective method for coating the metals. This method vastly has been studied for coating Aluminum, Titanium and Magnesium and their alloys and recently for steel. In present study, Ck45 steel samples were coated by PEO method in order to improve corrosion resistance. During this process specimens were immerged in carbonate solution contains sodium dehydrogen phosphate (NaH2PO4) and sodium carbonate (Na2CO3) with PH equaled 8.3. Composition and microstructure of the coating were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical corrosion behavior of coated and uncoated species was verified in 3.5% NaCl solution by potentiodynamic polarization technique. The result of XRD and SEM test showed that nanocrystale particles of Fe3O4 were successfully formed on the surface of samples while the average size of particles and phase were less than 800nm. Grain size was estimated about less than 80 nm. Corrosion test exhibited the remarkable improvement (about three times) in corrosion resistance of coated samples (16023 Ω) compared with those without coating (5200.4 Ω). تفاصيل المقالة -
حرية الوصول المقاله
127 - اثرات سمیت سلولی پروتئین کریستالی توکسین باسیلوس تورنجینسیس بر روی انگل لیشمانیا تروپیکا
نغمه فریدونی الهام معظمیان منوچهر رسولیسابقه و هدف: لیشمانیوز گروهی از بیماری های عفونی هستند که توسط انگل داخل سلولی اجباری از جنس لیشمانیا از راسته کینتوپلاست داران ایجاد می گردد. استفاده از عوامل کنترل کننده زیستی-میکروبی به عنوان یکی از روش های جایگزین درمانی عفونت های لیشمانیایی توسعه یافته است. هدف از أکثرسابقه و هدف: لیشمانیوز گروهی از بیماری های عفونی هستند که توسط انگل داخل سلولی اجباری از جنس لیشمانیا از راسته کینتوپلاست داران ایجاد می گردد. استفاده از عوامل کنترل کننده زیستی-میکروبی به عنوان یکی از روش های جایگزین درمانی عفونت های لیشمانیایی توسعه یافته است. هدف از این مطالعه، بررسی تاثیر فعالیت های پروتئین های کریستالی باسیلوس تورنجنسیس علیه انگل لیشمانیا تروپیکا می باشد.مواد و روش ها: در این مطالعه مقطعی-توصیفی، 47 جدایه باکتری باسیلوس تورنجنسیس از نمونه های خاک مناطق مختلف استان فارس بر اساس ویژگی های فنوتیپی، رنگ آمیزی توکسین کریستالی، مشاهده با میکروسکوپ نوری و شناسایی مولکولی جداسازی شدند. پس از هضم آنزیمی توکسین های جداسازی شده با استفاده از پروتئیناز K، فعالیت سیتوسیدالی آنها بر روی گونه لیشمانیا تروپیکا ارزیابی گردید. جدایه هایی که بیشترین تاثیر توکسیسیتی را داشتند، با استفاده از واکنش زنجیره ای پلی مراز نوع توکسین مشخص گردید.یافته ها: در این مطالعه ، یک جدایه با بیشترین ویژگی سیتوسیدالی بر روی گونه لیشمانیا تروپیکا شناسایی گردید. توکسین کریستالی Cry1 جدایه 35sb بر روی این گونه لیشمانیا موثر بود. این توکسین در غلظت 1-10 میلی گرم بر میلی لیتر بیشترین خاصیت سیتوسیدالی (حدود 40 درصد) را داشت. اثرات سیتوپاتیک پروماستیگوت های تیمار شده با توکسین کریستالی به صورت کوتاه و متورم شدن مشاهده گردید.نتیجه گیری: با توجه به نتایج این پژوهش ، پیشنهاد می گردد که پروتئین های کریستالی باسیلوس تورنجینسیس می توانند با انجام مطالعات تکمیلی به عنوان یک کاندیدای مناسب در درمان بیماری لیشمانیوز مطرح باشند. تفاصيل المقالة -
حرية الوصول المقاله
128 - Degradation of crystal violet using copper modified iron oxide as heterogeneous photo-fenton reagent
Pinki B. Punjabi Noopur Ameta Jyoti Sharma Kiran Chanderia Rakshit AmetaThe heterogeneous photo-Fenton degradation of crystal violet under visible light has been investigated usingcopper modified iron oxide. The photocatalyst has been prepared by coprecipitation method. The rate ofphotocatalyic degradation of dye was monitored spectrophotom أکثرThe heterogeneous photo-Fenton degradation of crystal violet under visible light has been investigated usingcopper modified iron oxide. The photocatalyst has been prepared by coprecipitation method. The rate ofphotocatalyic degradation of dye was monitored spectrophotometrically. It has been observed thatphotocatalytic degradation follows pseudo first order kinetics. The effect of various parameters like pH,concentration of dye, amount of photocatalyst, amount of H2O2 and light intensity on the rate of photo-Fenton degradation has also been observed. Photocatalyst has been characterized by IR spectroscopy,scanning electron microscopy and X-ray diffraction. Chemical Oxygen Demand (COD) of the reactionmixture before and after exposure was determined. A tentative mechanism for the photocatalytic degradationof crystal violet has also been proposed. Involvement of •OH radicals has been confirmed by usingisopropanol and butylated hydroxy toluene (BHT) as •OH radical scavengers. It has been observed that rateof reaction is drastically reduced in the presence of these scavangers. Under similar conditions Fe2O3 hasalso been prepared. The efficiency of Fe2O3 and copper modified Fe2O3 has been compared for thephotocatalytic degradation of crystal violet.NN+NCl-Structure of crystal violet تفاصيل المقالة -
حرية الوصول المقاله
129 - Green Synthesis of Silver Nanoparticles Using Pimpinella anisum L. Seed Aqueous Extract and Its Antioxidant Activity
Hashem Akhlaghi Sedighe sadat AkhlaghiAn aqueous extract of Pimpinella anisum was used for green synthesis of silver nanoparticles by bio reduction of an aqueous solution of silver nitrate. Silver nanoparticles were characterized by UV–Vis spectrometry, Fourier transform infrared spectroscopy (FTIR), X-ra أکثرAn aqueous extract of Pimpinella anisum was used for green synthesis of silver nanoparticles by bio reduction of an aqueous solution of silver nitrate. Silver nanoparticles were characterized by UV–Vis spectrometry, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDAX). The increase in absorption at 420 nm was used for recording the formation of a colloidal suspension of silver nanoparticles. The binding properties of the capped Ag nanoparticles synthesized from aqueous extract of P. anisum were analyzed by FTIR. XRD studies revealed that most of the nanoparticles were cubic and face centered cubic in shape. SEM analysis showed the size and shape of silver nanoparticles and EDAX confirmed the presence of silver. The synthesized silver nanoparticles showed DPPH free radical scavenging activity. تفاصيل المقالة -
حرية الوصول المقاله
130 - Preparation of a Novel Magnetic Nanocomposite Hydrogel Based on Carboxymethyl Chitosan for the Adsorption of Crystal Violet as Cationic Dye
Meysam Akbarzadeh Mohammad Taghi Vardini Gholam Reza MahdaviniaThe novel magnetic carboxymethyl chitosan/poly (acrylic amide) hydrogel (m-CMC-PAMH) was prepared using magnetic montmorillonite (m-MMT) and characterized by Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), scanning electron micro أکثرThe novel magnetic carboxymethyl chitosan/poly (acrylic amide) hydrogel (m-CMC-PAMH) was prepared using magnetic montmorillonite (m-MMT) and characterized by Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and vibrating sample magnetometry (VSM) techniques. Results showed that m-CMC-PAMH has been prepared successfully properties without damaging the crystal structure of Fe3O4. Adsorption capacity of Crystal Violet (CV) on the m-CMC-PAMH was 72.4 mg/g. The CV adsorption well described by the pseudo-second-order kinetics and Langmuir isotherm equations. The positive value of the enthalpy change ΔH° (23.5 kJ/mol) showed that the adsorption was endothermic and physical in nature. The value of Gibbs free energy change ΔG° was found to be -9.7 kJ/mol at 295 K for m-CMC-PAMH, which shows spontaneity of the CV adsorption. So, m-CMC-PAMH can be used as a low-cost alternative to other adsorbents for the removal of dyes from aqueous solutions. تفاصيل المقالة -
حرية الوصول المقاله
131 - بررسی اثر حضور نانوذرات نقره بر بلورینگی پلی اتیلن
مریم ابارشی سکینه مسگر شاهرودیدر این تحقیق، به منظور بررسی نقش نانوذرات نقره در بلورینگی پلی اتیلن، ابتدا نانوذرات نقره به روش کاهش شیمیایی ساخته و با کمک روش های الگوی پراش پرتو X، طیف سنجی مرئی-فرابنفش و میکروسکوپ الکترونی عبوری شناسایی شدند. میانگین اندزه ی نانوبلورک های نقره 21/7 نانومتر تعیین ش أکثردر این تحقیق، به منظور بررسی نقش نانوذرات نقره در بلورینگی پلی اتیلن، ابتدا نانوذرات نقره به روش کاهش شیمیایی ساخته و با کمک روش های الگوی پراش پرتو X، طیف سنجی مرئی-فرابنفش و میکروسکوپ الکترونی عبوری شناسایی شدند. میانگین اندزه ی نانوبلورک های نقره 21/7 نانومتر تعیین شد. سپس ترکیب های مختلفی از نانوکامپوزیت های پلی اتیلن-نقره شامل 5، 10، 20 و 30 درصد وزنی نانوذرات نقره به روش آسیاکاری مکانیکی تهیه شدند. پس از شناسایی نمونه ها به کمک الگوی پراش پرتو X و میکروسکوپ الکترونی روبشی5، اثر حضور نانوذرات نقره بر درجه ی بلورینگی پلی اتیلن به روش نارا وکومیا مورد بررسی قرار گرفت. نتایج این بررسی نشان داد که با افزایش درصد وزنی نانوذرات نقره، درجه ی بلورینگی پلی اتیلن به طور قابل ملاحظه ای تغییر می کند، به طوری که با افزودن نانوذرات نقره از صفر تا 30 درصد وزنی، درجه ی بلورینگی پلی اتیلن از 63/64 به 77/67درصد افزایش می یابد. تفاصيل المقالة -
حرية الوصول المقاله
132 - بررسی تاثیر متغیرهای تولید بر رسانایی الکتریکی و ریزسختی آلیاژ نانوکریستالی Cu-5 at. %Ta
روح اله رحمانی فرد محسن اسدی اسد آباد سید میثم جاویداندر پژوهش حاضر از روش آلیاژسازی مکانیکی برای تولید آلیاژهای نانوکریستالی Cu-5 at. % Ta استفاده شد. به منظور دستیابی به نمونه های با خواص مطلوب اثر تغییر اندازه گلوله های آسیا، اتمسفر و دمای تف جوشی بر ریزساختار، رسانایی الکتریکی و ریزسختی نمونه فوق مورد بررسی قرار گرفتند أکثردر پژوهش حاضر از روش آلیاژسازی مکانیکی برای تولید آلیاژهای نانوکریستالی Cu-5 at. % Ta استفاده شد. به منظور دستیابی به نمونه های با خواص مطلوب اثر تغییر اندازه گلوله های آسیا، اتمسفر و دمای تف جوشی بر ریزساختار، رسانایی الکتریکی و ریزسختی نمونه فوق مورد بررسی قرار گرفتند. بررسی های ریزساختاری از دو شرایط گلوله های به قطر 10 میلی متر و مخلوطی از گلوله های 10 و 5 میلیمتری نشان داد که نمونه ی آسیاشده با استفاده از گلوله های مخلوط، متوسط اندازه کریستالیت ریزتری دارد. پس از آسیاکاری، روش پرس سرد و تف جوشی در کوره در اتمسفرهای نیتروژن، آرگون و خلأ در دمای ℃550 انجام شد، نمونه های تف جوشی شده در شرایط خلأ مجموعه خواص بهتری را از خود نشان دادند. به منظور بررسی اثر دمای تف جوشی بر خواص محصول دماهای 700 و ℃850 نیز در شرایط خلأ مورد بررسی قرار گرفتند، نتایج نشان دادکه نمونه ی تف جوشی شده در دمای ℃850 بیشترین میزان رسانایی الکتریکی و ریزسختی را دارد. درمجموع نمونه ی آسیاشده با گلوله های مخلوط و تف جوشی شده در دمای ℃850 در شرایط خلأ میزان رسانایی الکتریکی برابر IACS %7/15 و ریزسختی HV 2/196 را نشان داد که بیشترین میزان رسانایی الکتریکی و ریزسختی در بین نمونه های مس- تانتالم تولیدشده در این پژوهش بود. تفاصيل المقالة -
حرية الوصول المقاله
133 - تاثیر پارامتر های ترمومکانیکی بر رفتار بافت آلیاژ منیزیم AZ63
غلامرضا ابراهیمی مهدی کاویانیبه منظور بررسی تاثیر پارامتر های ترمومکانیکی بر رفتار بافت آلیاژ منیزیم AZ63، آزمون فشار گرم بر روی نمونه های اکسترود شده آلیاژ منیزیم AZ63 انجام شد. ابتدا نمونه ها در دو جهت اکسترود و جهت نرمال ماشین کاری شدند. سپس آزمون فشار گرم در دمای °C 250 و نرخ کرنش های s-1 0 أکثربه منظور بررسی تاثیر پارامتر های ترمومکانیکی بر رفتار بافت آلیاژ منیزیم AZ63، آزمون فشار گرم بر روی نمونه های اکسترود شده آلیاژ منیزیم AZ63 انجام شد. ابتدا نمونه ها در دو جهت اکسترود و جهت نرمال ماشین کاری شدند. سپس آزمون فشار گرم در دمای °C 250 و نرخ کرنش های s-1 01/0 و s-1 1 و کرنش های مختلف انجام شد. بررسی های ریزساختاری و تغییرات بافت نشان می دهد که در کرنش های اولیه تغییر شکل فشار گرم، در نمونه های جهت اکسترود دوقلویی های کششی منجر به تقویت بافت قاعده در جهت نورد و دوقلویی های فشاری در نمونه های جهت نرمال باعث تغییر بافت به سمت جهت عرضی می شوند. همچنین با توجه به تغییرات بافت توسط تصاویر قطبی مشخص شده است که در کرنش های بالا در نمونه های جهت نرمال، تبلور مجدد دینامیکی منجر به کاهش شدت بافت قاعده شده است. تفاصيل المقالة -
حرية الوصول المقاله
134 - بررسی اثر دما و زمان کلسیناسیون بر سنتز YAG نانو کریستال با استفاده از روش هم رسوبی نرمال
امید میرزایی مهسا رحمانی محمد تجلیایتریوم-آلومینیوم-گارنت (YAG، با فرمول شیمیایی Y3Al5O12) نانو کریستال از طریق روش همرسوبی نرمال با استفاده از ایتریا و نیترات آلومینیوم به عنوان مواد اولیه و آمونیوم هیدرژن کربنات (AHC، NH4HCO3) به عنوان عامل رسوبگر سنتز شد. برای بررسی اثر دما و زمان کلسیناسیون پیش ماده أکثرایتریوم-آلومینیوم-گارنت (YAG، با فرمول شیمیایی Y3Al5O12) نانو کریستال از طریق روش همرسوبی نرمال با استفاده از ایتریا و نیترات آلومینیوم به عنوان مواد اولیه و آمونیوم هیدرژن کربنات (AHC، NH4HCO3) به عنوان عامل رسوبگر سنتز شد. برای بررسی اثر دما و زمان کلسیناسیون پیش ماده حاصل در دمای C° 1100-900 به مدت 2 ساعت و همچنین در دمای C° 1100 در زمانهای مختلف دیگر (15، 30، 45 و 60 دقیقه) تحت کلسیناسیون قرار گرفت. تغییرات ترکیب فاز و ریزساختار نمونههای سنتز شده توسط روشهای مختلفی از قبیل پراش پرتو ایکس (XRD)، طیف سنجی تبدیل فوریه مادون قرمز (FTIR)، آنالیز حرارتی (TG/DTA)، آنالیز سطح ویژه (BET) و میکروسکوپ الکترونی روبشی گسیل میدانی (FESEM) مورد بررسی قرار گرفتند. فاز مکعبی YAG با متوسط اندازه ذرات nm 33 و میزان سطح ویژه m2/g 30 در دمای C° 1000 تشکیل شد. از طرف دیگر نانو کریستال YAG خالص با کلسینه کردن تنها به مدت 15 دقیقه در دمای C° 1100 نیز حاصل شد. نتایج نشان داد افزایش دمای کلسیناسیون نسبت به زمان اثر بسیار بیشتری در افزایش اندازه متوسط کریستال ها و ذرات داشته است. تفاصيل المقالة -
حرية الوصول المقاله
135 - تاثیر ریزساختار و بافت کریستالی بر مقاومت به ترک هیدروژنی فولاد HSLA، سرد شده در محیط های مختلف
شهرام عباسی محمد اسماعیلیان شاهرخ آهنگرانیدر این تحقیق اثر ریزساختار و مولفه های بافت کریستالی بر مقاومت به ترک هیدروژنی فولاد میکروآلیاژی استحکام بالا(HSLA) مورد بررسی قرار گرفت. به این منظور فولاد مورد نظر تا 50% در بازه دمایی 980 تا 750 درجه سانتی گراد نورد گرم و سپس در محیط های مختلفی سرد شد. ریزساختار و با أکثردر این تحقیق اثر ریزساختار و مولفه های بافت کریستالی بر مقاومت به ترک هیدروژنی فولاد میکروآلیاژی استحکام بالا(HSLA) مورد بررسی قرار گرفت. به این منظور فولاد مورد نظر تا 50% در بازه دمایی 980 تا 750 درجه سانتی گراد نورد گرم و سپس در محیط های مختلفی سرد شد. ریزساختار و بافت نمونه با استفاده از میکروسکوپ الکترونی روبشی (SEM) مجهز به آشکار ساز الکترون های بازگشتی (EBSD) مورد بررسی قرار گرفت و آزمون حساسیت به ترک هیدروژنی (HIC) نیز روی نمونه ها انجام شد. نتایج نشان داد که با افزایش سرعت سرمایش ساختار به سمت تشکیل فازهای غیرتعادلی با اندازه دانه کوچکتر و سهم مرزدانه بیشتر پیش می رود که مقاومت به ترک هیدروژنی را کاهش می دهد. از طرف دیگر افزایش سرعت سرمایش باعث تغییرات قابل توجه در بافت نمونه و کاهش شدت مولفه های بافت می شود. همچنین کاهش شدت رشته {111} // ND در ساختار فولاد با افزایش سرعت سرمایش مشاهده شد که کاهش سهم این رشته نشان دهنده کاهش مقاومت به رشد ترک بین دانه ای و نتیجتاً مقاومت به ترک هیدروژنی می شود. تفاصيل المقالة -
حرية الوصول المقاله
136 - بررسی فرآیندهای ترمیم دینامیکی و استاتیکی در تغییرشکل گرم آلیاژ تیتانیوم SP-700
امیرحسین شیخعلی مریم مرکباتی سید مهدی عباسیبه منظور بررسی فرآیندهای ترمیم دینامیکی و استاتیکی آلیاژ SP-700، در این تحقیق آزمایش پیچش گرم پیوسته و منقطع در دماهای 850 و ºC1000 با کرنشها و زمانهای بین پاسی مختلف انجام شد. مکانیزم غالب تغییرشکل در دمای ºC1000، تبلورمجدد دینامیکی (DRX) است. درحالیکه در د أکثربه منظور بررسی فرآیندهای ترمیم دینامیکی و استاتیکی آلیاژ SP-700، در این تحقیق آزمایش پیچش گرم پیوسته و منقطع در دماهای 850 و ºC1000 با کرنشها و زمانهای بین پاسی مختلف انجام شد. مکانیزم غالب تغییرشکل در دمای ºC1000، تبلورمجدد دینامیکی (DRX) است. درحالیکه در دمای ºC850، تضرس و درهم تنیدگی مرزدانهها مشاهده شد. با این وجود ریزساختار نمونه پیچش گرم در دمای ºC850 حاوی دانههای ریز (10-3 میکرون) بوده که بیانگر وقوع تبلورمجدد دینامیکی است. دانههای تبلورمجدد یافته در اطراف مرزدانهها و نقاط سهگانه از طریق مکانیزم تحدب تشکیل شدهاند. با افزایش کرنش پاس اول (5/0ε=) در دمای ºC1000، بدلیل افزایش نیرو محرکه جوانهزنی و رشد دانههای جدید، سینتیک فرآیند ترمیم استاتیکی نیز افزایش مییابد. اما در کرنشهای حالت پایدار (1ε=) بدلیل وقوع تبلورمجدد دینامیکی کامل حین تغییرشکل، نیرو محرکه و در نتیجه سینتیک فرآیند ترمیم استاتیکی کمتر است. در واقع، در دمای ºC850 علاوه بر ترمیم استاتیکی، وقوع استحاله فازی α به β نیز در کسر نرمشدگی تاثیر دارد. تفاصيل المقالة -
حرية الوصول المقاله
137 - بررسی اثر اندازه در آزمون فشار به کمک مدل ترکیبی هیل- تیلور
فراز رحیم زاده لطف آباد رامین ابراهیمیدر این مقاله، ابتدا با ترکیب مفاهیم پلاستیستهی کریستال ارائه شده توسط تیلور و فرم ریاضی معیار تسلیم هیل برای توصیف ناهمسانگردی، مدل نوینی جهت توصیف پاسخ مکانیکی دانهها در نمونه برحسب جهتگیری آنها توسعه داده شد. مزیت این روش نسبت به دیگر روشهای المان محدود پلاستیسته أکثردر این مقاله، ابتدا با ترکیب مفاهیم پلاستیستهی کریستال ارائه شده توسط تیلور و فرم ریاضی معیار تسلیم هیل برای توصیف ناهمسانگردی، مدل نوینی جهت توصیف پاسخ مکانیکی دانهها در نمونه برحسب جهتگیری آنها توسعه داده شد. مزیت این روش نسبت به دیگر روشهای المان محدود پلاستیستهی کریستال در آن است که در کدهای مرسوم پلاستیسیتهی کریستال، عموماً تمام سیستمهای لغزش فعال در نظر گرفته میشوند که این فرض معتبر نیست، اما در این روش، تغییر شکل با 5 سیستم لغزش مدنظر قرار میگیرد. با بهکارگیری این مدل که مدل ترکیبی هیل-تیلور نامیده شد، آزمون فشار نمونههایی متشکل از تعداد دانهی مختلف با جهتگیری تصادفی شبیهسازی شد و حالت کرنش هر دانه و شرط رفع اثر اندازه در هندسهی نهایی نمونه، مورد بررسی قرار گرفت. نتایج این پژوهش حاکی از آن است که حالت کرنش هر دانه در ماده وابسته به جهتگیری آن، منحصر به فرد بوده و حالت کرنش با عبور از مرز دانهها بهصورت ناگهانی تغییر میکند. همچنین مشاهده شد که با افزایش تعداد دانهها، هندسهی نهایی به هندسهی ایدهآلی که در آزمون فشار مورد انتظار است نزدیک میشود. میل کردن هندسه نهایی به هندسه ایدهآل، از نقطهنظر آماری مورد بررسی قرار گرفت و مشخص شد با افزایش تعداد دانهها در یک سطح مقطع ثابت با وجود حفظ پراکندگی حالت کرنش دانهها، میانگین حالت کرنش در مسیرهای شعاعی مختلف به سمت حالت کرنش ایدهآل میل میکند. تفاصيل المقالة -
حرية الوصول المقاله
138 - The Effect of Heat Treatment on Springing of AISI301
Majid Karimian Ehsan Nourouzi Esfahani Mohammad BagherboomAISI 301 stainless steel is a frequently used metal, especially in high temperature demands and or in part with high corrosion risk. Thin spring steel plates can be used as expansions of heat furnaces insulation and variety of all other springs. The present study has as أکثرAISI 301 stainless steel is a frequently used metal, especially in high temperature demands and or in part with high corrosion risk. Thin spring steel plates can be used as expansions of heat furnaces insulation and variety of all other springs. The present study has assessed the effects of temperature and thermal treatment time span on the microstructure of stainless steel 301 to achieve elasticity and found out that microstructure gets smaller. As well as the Martensitic ά phase in the sample distributes uniformly after thermal treatment at 450 ºC for 20 minutes then water quenched in 10 ºC. By using X-ray diffraction, it can be found that the reduction in crystalline size of the Martensite ά and increasing in Martensite volume fraction is the cause of the elasticity of the samples. All obtained results confirmed by Ferittscope test. تفاصيل المقالة -
حرية الوصول المقاله
139 - Evaluation of Tool Performance With Nanocrystalline Multilayer Coatings on the Machinability of Superalloy Inconel 718
رسول مختاری همامی بهروز موحدی ایرج لیرابی مهدی بازرگان حقیقیIn this paper, the performance of the cutting tool with nanocrystalline multilayer coatings (TiN+TiAlN) for machining of superalloy Inconel 718 in the dry and wet conditions was studied. The multi layer TiN and TiAlN with nanocrystalline structure was applied by physica أکثرIn this paper, the performance of the cutting tool with nanocrystalline multilayer coatings (TiN+TiAlN) for machining of superalloy Inconel 718 in the dry and wet conditions was studied. The multi layer TiN and TiAlN with nanocrystalline structure was applied by physical vapor deposition technique (arc evaporation) on the WC-Co inserts. The results of the ball on disc wear test and the machining of superalloy Inconel 718 in wet and dry conditions indicated that the nanocrystalline coatings could produce better performance of tools in turning. Abrasion and adhesive wear resistance improved by nanocrystalline and modified Aluminum composition in TiAlN coating as well as toughness and thermal stability. تفاصيل المقالة -
حرية الوصول المقاله
140 - Effect of Lighting Schedule during Incubation on Embryonic Development and Bone Gene (Col10a1, Spp1, Bglap, and Alp) Expression in Broiler Hatchlings
S.M. Hashemian M.J. Zamiri Z. Khaksar Z. Ansari Pirsaraei H.R. MoradiWe studied the effect of lighting during 19 days of incubation on embryonic bone characteristics, gene ex-pression, thyroid hormones, and glucose in Cobb broiler hatchlings. Eggs (2160) were incubated under darkness (control) and green and white lighting (16D:8L and 12D أکثرWe studied the effect of lighting during 19 days of incubation on embryonic bone characteristics, gene ex-pression, thyroid hormones, and glucose in Cobb broiler hatchlings. Eggs (2160) were incubated under darkness (control) and green and white lighting (16D:8L and 12D:12L). On 19th day, tibiotarsal length in-creased under eight hours of white light, and femoral ossified length was longer under eight hours of white and green light. In femur, expression of Alp, Col10a1, and Spp1 increased by 12 h white and 8 h green lighting, and Bglap expression decreased under white. In tibiotarsus, expression of Alp decreased by 8 h lighting (green or white) while Bglap increased by 12 h lighting (green or white). Tibiotarsal expression of Col10a1 increased by 12 h lighting (white and green), and in 8 h green lighting, and Spp1 expression was higher under light illumination. The hatchling blood triiodothyronine concentration in 8 h green lighting was higher than that in control, whereas, thyroxine concentration was lower under 12 h white lighting com-pared with other treatments. Femoral organic matter to mineral (OM:M) ratio and calcium concentration were higher in the eight-hour white light group than in the control, but tibiotarsal OM:M ratio and calcium and phosphorus concentrations were higher under 12 h white light. The findings indicated that lighting dur-ing incubation may impact, both positively and negatively, bone morphology and gene expression. More studies are needed to find the most beneficial lighting system during incubation in chickens. تفاصيل المقالة -
حرية الوصول المقاله
141 - Exploration of metabolic variations, anti-cholinesterase, anti-heme biocrystallization, and anti-protein denaturation activities of ten Capsicum accessions under different stages of ripening
Mamita Debnath Jhelam Chatterjee Susmita DasHydro-methanolic extracts of pericarps and seeds of 10 different Capsicum cultivars from three different species viz., Capsicum chinense, C. annuum and C. frutescens were assessed to determine metabolic variations and anti-cholinesterase, anti-malarial and anti-protein أکثرHydro-methanolic extracts of pericarps and seeds of 10 different Capsicum cultivars from three different species viz., Capsicum chinense, C. annuum and C. frutescens were assessed to determine metabolic variations and anti-cholinesterase, anti-malarial and anti-protein denaturation activities at four different stages of ripening, namely green unripe (GU), turning green-orange (TGO), orange ripe (OR) and red fully ripe (RFR) stages. Many of the ripening stages of the tested cultivars showed significant bioactivities in a dose-dependent manner. In addition, metabolites were identified using GC/MS. On the other hand, HPLC analysis revealed the highest capsaicin and dihydrocapsaicin content in the pericarp of GU, TGO and RFR stages of C. chinense. β-Carotene, capsanthin and lutein contents of C. chinense were also measured using HPTLC technique. The GU and RFR stages of C. chinense contained appropriate amounts of all three carotenoids. These results may be helpful in selecting the cultivars with the best attributes. تفاصيل المقالة
سند
Sanad is a platform for managing Azad University publications
الروابط
المراكز ذات الصلة
دعامة
الصفحات الرسمية
حقوق هذا الموقع الإلكتروني مملوكة لنظام SANAD Press Management. © 1442-1446