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Open Access Article
1 - CATALYTIC REFORMING OF n-HEPTANE ON PLATINUM-TUNGSTEN SUPPORTED ON GAMMA-ALUMINA
M. Vadi A. Safavi A. Jamshidi -
Open Access Article
2 - Effect of Ultraviolet and Tungsten Rays on Aflatoxin B1 in Rice Flour
M. Bazgir H. Mohammadimanesh S.R. FaniIntroduction: Aflatoxins are secondary metabolites produced by some species of Aspergillus fungus on agricultural products. They have great health, medical and economic significance due to mutagenic and carcinogenic effects on consumers. The purpose of this study is to MoreIntroduction: Aflatoxins are secondary metabolites produced by some species of Aspergillus fungus on agricultural products. They have great health, medical and economic significance due to mutagenic and carcinogenic effects on consumers. The purpose of this study is to compare ultraviolet and tungsten rays in reducing aflatoxin B1 in rice flour. Materials and Methods: Contaminated rice flour with two concentrations of 50 and 100 ng/g of aflatoxin B1 that produced by Aspergillus flavus in the laboratory were illuminated at 5 times 10, 20, 30, 40 and 50 minutes, with two different distances of 7 and 14 cm from ultraviolet light source with wavelength 366 nm and tungsten 100 W. Aflatoxin content was measured using competitive ELISA in two replications. Aflatoxin levels were compared with control samples by SAS (Release 9.1, SAS Institute Inc., Cary, NC) software using Duncan test. Results: The results showed that maximum (67 and 68%) and minimum (14 and 18%) reduction of aflatoxin B1 occur after 50 and 10 minutes irradiation at 7 and 14 cm, by ultraviolet and tungsten light, respectively. The initial concentrations of Aflatoxin B1 did not affect the test, but reducing the distance to the source of light and increasing exposure time led to a further reduction of aflatoxin (P≤0.01). Conclusion: Reducing the distance between rice flour and ultraviolet or tungsten ray source decreases aflatoxin further. On the other hand, the longer exposure to radiation, the more aflatoxin declines. The use of these rays can be considered in aflatoxin mitigation of food. Manuscript profile -
Open Access Article
3 - Investigating the Effect of Joint Geometry of the Gas Tungsten Arc Welding Process on the Residual Stress and Distortion using the Finite Element Method
A Shiri A Heidari -
Open Access Article
4 - Statistical Approach on Corrosion Behavior of Dissimilar Welds of A387-Gr91/AISI316 Steels with PCGTAW Process
Mohammad Jula Reza Dehmolaei Seyed Reza Alavi Zaree -
Open Access Article
5 - Study the effect of the friction stir process on the microstructure and mechanical behavior of the AZ31 as-cast alloy joint
Amir Rezaee Iman Ebrahimzadeh Farhad Gharavi -
Open Access Article
6 - Simultaneously Modeling and Optimization of Heat Affected Zone and Tensile Strength in GTAW Process Using Simulated Annealing Algorithm
Meysam Beytolamani Masoud Azadi Moghaddam Farhad Kolahan -
Open Access Article
7 - Effect of Deposition Regime on Tribological Behavior of VK8Coating on 1.2344 Tool Steel Obtained by Electro Spark Method
M Aghakhani A Shafyeib H Monajatizadea M. A Aghakhani -
Open Access Article
8 - Degradation of p-nitrophenol (PNP) in aqueous media by tungsten oxide-based photocatalyst using visible light
فاطمه هدایتی نسب علیرضا زارعی هادی رضایی وحیدیانPara-Nitrophenol (PNP) as a nitroaromatic matter is a hazardous pollutant in industrial wastewaters. In this paper degradation of the pollutant was performed by the catalysts of CuWO4/CuO, Na0.01WO3, and WO3 under visible light. The catalysts were synthesized by hydroth MorePara-Nitrophenol (PNP) as a nitroaromatic matter is a hazardous pollutant in industrial wastewaters. In this paper degradation of the pollutant was performed by the catalysts of CuWO4/CuO, Na0.01WO3, and WO3 under visible light. The catalysts were synthesized by hydrothermal method and the process was performed in a suspension reactor equipped with a metal halid lamp (400 W). The synthesized catalysts were characterized using X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), and Diffuse reflection spectroscopy (DRS). The effective parameters of pH, reaction temperature, and light intensity have been studied. The results showed that using [Catalyst] = 2000 ppm, [PNP] = 20 ppm, T = 25 °C, and pH = 12 after 240 min, the degradation efficiency for WO3, Na0.01WO3, and CuWO4/CuO obtained about 40%, 42.3%, and 30%, respectively. Manuscript profile -
Open Access Article
9 - Comparison of Corrosion behavior of aluminium 6061 alloy joined by friction stir lap welding and gas tungsten arc lap welding methods
reza bazarganlari ehsan vafaIn this paper wrought aluminum sheets with thickness of 5 mm were square butt welded by friction stir lap welding (FSLW) and gas tungsten arc lap welding (GTALW) methods to campare their corrosion behavior. of the welding zone was probed by tafel polarization curve. Opt MoreIn this paper wrought aluminum sheets with thickness of 5 mm were square butt welded by friction stir lap welding (FSLW) and gas tungsten arc lap welding (GTALW) methods to campare their corrosion behavior. of the welding zone was probed by tafel polarization curve. Optical metallography (OM) and scaninig electron microscop (SEM) were used to study morphology. Energy dispersive spectroscopy (EDS) were used to analysis different zone of the welds. EDS analysis proved deposits of iron and silicon in samples. FSLW and GTALW resulted in equiaxed grains of about 5 and 18 micrometr respectively, while GTALW caused dendritic structure of the welded region. To assessment mechanical properties, micro hardness test were accure. Resistance to corrosion was greater for the FSLW grains than the GTALW structure. In both cases, susceptibility to corrosion attack was greater in the welded region than the base metal section. . microhardness of FSLW specimen were grater than GTALW specimen. Manuscript profile -
Open Access Article
10 - The effect of parameters of pulse Electrodeposition and post annealing on properties of Cobalt-tungsten alloy coating
سمیه اباذری سیوندی سعید رستگاری شهرام خیراندیشcobalt-tungsten anano structure alloy coating was produced using pulse electrodeposition in 200 Hz pulse frequency from citrate electrolyte at 60 °C. In this study the influence of cobalt ions concentration in solution and duty cycle on crystal structure, grain size Morecobalt-tungsten anano structure alloy coating was produced using pulse electrodeposition in 200 Hz pulse frequency from citrate electrolyte at 60 °C. In this study the influence of cobalt ions concentration in solution and duty cycle on crystal structure, grain size, hardness and corrosion resistance of coating was investigated. Surface morphology and composition of coatings was examined by scanning electron microscopy (SEM) and (EDS) analysis. The crystallite size of the coatings calculated from the x-ray diffraction patterns using the Scherrer equation. Micro hardness of the coatings was assessed using a Vickers micro-indenter. Results showed that electrodeposited coating at 0.2 mol/l cobalt sulphate and 60% duty cycle with 1A/dm2had optimum coating on 758 Hv. Annealing amorphous coating was produced at current density of 4 A/dm2 in high vacuum pressure makes crystalline coating. Increasing temperature at 600°C makes a well-developed polycrystalline structure of Co3W and CowO4 in the coating. Microhardness of coating increased from 436 Hv to 1059 Hv after heat treatment at 600 °C. Heat treatment of coating improved the corrosion resistance of coating. The coating heat treated at 400 ºC had minimum corrosion rate. Manuscript profile -
Open Access Article
11 - Aluminum alloy (АМГ6М) joining by two processes of friction-stir and non-consumable Tungsten electrode welding and comparison of their mechanical and microstructure properties
Aliasghar Torabi Tahmineh Ahmadi Afshin Shirali Mohammadreza Khanzadeh ghareshiran Majid TaghianThe purpose of this research is to investigate the possibility of replacement of arc welding under shielding gas with non-consumable Tungsten electrode (TIG) of Al АМГ6М alloy by friction stir welding (FSW). In this regard, after applying primary parameters for both wel MoreThe purpose of this research is to investigate the possibility of replacement of arc welding under shielding gas with non-consumable Tungsten electrode (TIG) of Al АМГ6М alloy by friction stir welding (FSW). In this regard, after applying primary parameters for both welding processes to obtain optimum parameters, the prepared samples were characterized with Tension, bending, radiography, hardness and distortion tests and also microstructure evaluation. The results of this study showed that the grain size of welding zone of TIG and FSW processes are 14 and 6 µm respectively, which are smaller than the base metal with 30 µm in size. The ultimate tensile strength of the FSW joints in the parallel to rolling direction and in the vertical direction with welding line is much more higher than TIG joints; 364 Mpa versus 278 Mpa. The reduction of microhardness in the welding zone for both process FSW and TIG have been in a range. The amount of distortion measured in the FSW was one-fourth of these values in TIG. The result of bending test of the FSW sample from the plane like to the results of the base metal is crack free. Therefore, in order to improve the mechanical and metallurgical properties, as well as to reduce weld joints distortion in aluminum structures, FSW was considered an appropriate alternative to the replacement of the arc welding under shielding gas with non-consumable tungsten electrode. Manuscript profile -
Open Access Article
12 - Investigating the Effect of Tungsten Element on the Microstructure and Mechanical Properties of Fe-C-Ni Hard Coating
Adel Mosadeghian hamid nazemy Mohammadreza Khanzadeh Gharahshiran Mansor SadeghiNasbIn this paper, the effect of tungsten element on microstructure and mechanical properties of Fe-C-Ni hard coating was investigated. Two hard coating electrodes were made with 10 and 30 gr of tungsten powder. The microstructure of the welding metals included fine carbide MoreIn this paper, the effect of tungsten element on microstructure and mechanical properties of Fe-C-Ni hard coating was investigated. Two hard coating electrodes were made with 10 and 30 gr of tungsten powder. The microstructure of the welding metals included fine carbides in the area of needle martensite and residual austenite. Electron microscopy studies showed that there were very fine cracks in the weld metal martensitic phase with 10 gr of tungsten but these microscopic cracks were not found in weld metal with 30 gr of tungsten. The results of the EDS analysis showed that the amount of soluble tungsten element in the austenite phase of both welding metals is high. This amount in weld metal with 30 gr of tungsten was about 3.66% higher than the weld metal with 10 gr of tungsten. The results of the XRD analysis showed that the phases present in the weld metal with 10 gr of tungsten included martensite, austenite and W2C carbide, but in the weld metal with 30 gr of tungsten in addition to these phases also iron oxides were observed. The results of hardness test showed that the average hardness of weld metal with 10 gr of tungsten is 42.5 RC and the average hardness of welding metal with 30 gr of tungsten is 49.6 RC. Manuscript profile -
Open Access Article
13 - Investigation of the Effects of HVOF Process Parameters on the Quality and Wear Properties of the Coating Tungsten Carbide on 4130 Steel
Javad Ansari Amirhossein Moghanian Morteza Saghafi YazdiPrevious studies have shown that thermal spraying methods on steels have extensive applications in various industries to increase high-quality wear-resistance coatings. One of these coatings, which is important in diverse industries and has been studied, is tungsten car MorePrevious studies have shown that thermal spraying methods on steels have extensive applications in various industries to increase high-quality wear-resistance coatings. One of these coatings, which is important in diverse industries and has been studied, is tungsten carbide. One of the methods of coating is the high-velocity oxygen fuel (HVOF) process. Scanning electron microscopy (SEM) was used to examine the microstructure of the coatings and also by examining SEM images from the lateral surface of the coated sample, the thickness and quality of the coating were examined. Additionally, X-ray diffraction (XRD) was used to determine the formed phases before and after the coating process and the results of the presence of WC and W6C2.54 carbides were confirmed.The wear test results showed that coated samples demonstrated higher wear resistance than the sample without coating (control). Meanwhile, the sample with spraying pressure of 7.2 Bar and a feeding powder rate of 72 g/min (W2) exhibited the best wear resistance among other coatings due to the more uniform distribution of tungsten carbide (WC) and less porosity. As a result, it was obtained that the spraying pressure in the process of HVOF process was more effective than the feeding rate of coating powders and a sample with the spray pressure of 7.2 Bar and powders feeding rate of 72 g/min (W2) was introduced as the optimal sample among all coatings with the highest abrasion wear resistance. Manuscript profile -
Open Access Article
14 - Fabrication and Optimization of Humidity Sensor Based on Porous Nanostructure Tungsten Trioxide / Silver Nanoparticles
Ayub Karimzad Ghavidel Gholamreza Kiani Mahsa MahdaviniaThe aim of this research is to fabricate a moisture sensor based on porous nanostructure of pure tungsten trioxide (WO3) and doped with silver nanoparticles (SN), and to use the properties of ohmic changes, capacitance and impedance versus moisture as output. The struct MoreThe aim of this research is to fabricate a moisture sensor based on porous nanostructure of pure tungsten trioxide (WO3) and doped with silver nanoparticles (SN), and to use the properties of ohmic changes, capacitance and impedance versus moisture as output. The structural characteristics of the prepared nanocomposite were examined by a scanning electron microscope and X-ray diffraction spectroscopy. The results showed that synthetic WO3 is in the form of spheres with dimensions of 3 to 7 μm, with a surface porous structure in size of 10 to 60 nm. To fabricate the sensors, first the materials were mixed and dispersed, then coated on the interdigitated electrode by sedimentation method. The investigation showed that the doped sensor with SN have a better performance in comparison with WO3 sample. Its sensitivity was obtained 4.4 and 0.68 MΩ/%RH for the relative humidity range of 20-50% and 50-90%, respectively, improved 7 and 5% compared to similar previous samples. The response and recovery time of this sensor was measured approximately 2 and 7 seconds, which is 37.5 and 41.4 times smaller than available samples, respectively. Decreasing the capacitance of the sensor to 3800 Pf by increasing the relative humidity to 90% is another finding. Significant impedance changes of the sensor versus the humidity alternations is other important result, showing that the impedance can be considered as a sensor output by compensating for errors of ohmic changes and capacitance. Manuscript profile
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