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دسترسی آزاد مقاله
1 - Application of Artificial Neural Network and Genetic Algorithm for Predicting three Important Parameters in Bakery Industries
H. Abbasi Z. Emam-Djomeh S. M. SeyedinFarinograph is the most frequently used equipment for empirical rheological measurements of dough. It’suseful to illustrate quality of flour, behavior of dough during mechanical handling and texturalcharacteristics of finished products. The percentage of water abs چکیده کاملFarinograph is the most frequently used equipment for empirical rheological measurements of dough. It’suseful to illustrate quality of flour, behavior of dough during mechanical handling and texturalcharacteristics of finished products. The percentage of water absorption and the development time of doughare the most important parameters of farinography for bakery industries during production. However,farinograph quality number is also a profitable factor for rapid evaluation of flour. Our purpose in presentresearch is to apply artificial neural networks (ANNs) for predicting three important parameters offarinograph from simple measurable physicochemical properties of flour. Genetic algorithm (GA) was alsoapplied in the training phase for optimizing different parameters of ANN’s structure and inputs. Sensitivityanalyses were also conducted to explore the ability of inputs in predicting the networks outputs. Two neuralnetworks were developed; the first for modeling water absorption and dough development time and thesecond for modeling farinograph quality number. Both developed ANNs using GA have excellent potentialin predicting the farinograph properties of dough. In developed models, gluten index and Zeleny, suitableparameters for qualitative measurements of samples, played the most important role for predicting doughfarinograph characterisations. پرونده مقاله -
دسترسی آزاد مقاله
2 - Microstructure and Swelling Behaviour of Poly (Acrylamide-co-Acrylic Acid) based Nanocomposite Superabsorbent Hydrogels
Ahmad Gholizadeh Sasan Ganjehie S. Ahmad KetabiIn this paper, microstructure and swelling behavior of five superabsorbent hydrogels have been investigated. These samples were prepared by dispersing watermelon shell powder (WSP) and cucumber shell powder (CSP), mixture bentonite and WSP, mixture bentonite and CSP, ze چکیده کاملIn this paper, microstructure and swelling behavior of five superabsorbent hydrogels have been investigated. These samples were prepared by dispersing watermelon shell powder (WSP) and cucumber shell powder (CSP), mixture bentonite and WSP, mixture bentonite and CSP, zeolite (Z) bentonite (B), into poly(acrylamide-co-acrylic acid) (P) backbone in an aqueous medium. The nanocomposites have been synthesized through chemical cross-linking by polymerization technique using N,N-methylenebis acrylamide as a cross-linker and potassium persulfate as an initiator in a simple aqueous environmental conditions. The nanocomposite hydrogels named as P-WSP-CSP، P-WSP-B، P-CSP-B، P-Z، P-B, respectively. These superabsorbent nanocomposites were characterized by X-ray diffraction, Fourier transform infrared and field emission-scanning electron microscope measurements. The water absorption and desorption of the superabsorbent nanocomposites have also been studied. Our findings show that very high water absorption and lower drying rate of P-CSP-B are attributed to higher porous surfaces observed in FE-SEM images. The results show the superabsorbent hydrogels based on CSP represent very high water absorbency capacity and water retention ability that make them suitable for technology applications. پرونده مقاله -
دسترسی آزاد مقاله
3 - Microstructure and Swelling Behaviour of Poly (Acrylamide-co-Acrylic Acid) based Nanocomposite Superabsorbent Hydrogels
Sasan Ganjehie Ahmad Gholizadeh Seyed Ahmad KetabiIn this paper, microstructure and swelling behavior of five superabsorbent hydrogels have been investigated. These samples were prepared by dispersing watermelon shell powder (WSP) and cucumber shell powder (CSP), mixture bentonite and WSP, mixture bentonite and CSP, ze چکیده کاملIn this paper, microstructure and swelling behavior of five superabsorbent hydrogels have been investigated. These samples were prepared by dispersing watermelon shell powder (WSP) and cucumber shell powder (CSP), mixture bentonite and WSP, mixture bentonite and CSP, zeolite (Z) bentonite (B), into poly(acrylamide-co-acrylic acid) (P) backbone in an aqueous medium. The nanocomposites have been synthesized through chemical cross-linking by polymerization technique using N,N-methylenebis acrylamide as a cross-linker and potassium persulfate as an initiator in simple aqueous environmental conditions. The nanocomposite hydrogels named as P-WSP-CSP، P-WSP-B، P-CSP-B، P-Z، P-B, respectively. These superabsorbent nanocomposites were characterized by X-ray diffraction, Fourier transforms infrared and field emission-scanning electron microscope measurements. The water absorption and desorption of the superabsorbent nanocomposites have also been studied. Our findings show that very high water absorption and lower drying rate of P-CSP-B are attributed to higher porous surfaces observed in FE-SEM images. The results show the superabsorbent hydrogels based on CSP represent very high water absorbency capacity and water retention ability that make them suitable for technology applications. پرونده مقاله -
دسترسی آزاد مقاله
4 - Evaluating the Potential of Polycaprolactone/Heparinized Nano Fluoro Hydroxyapatite Composite Scaffolds for Advancing Bone Tissue Engineering: A Comprehensive Analysis of Biodegradability and Water Absorption
Nila Haghani Nahid Hasanzadeh Nemati Mohammad Taghi Khorasani Shahin BonakdarThe primary purpose of this study is to produce a composite scaffold using polycaprolactone (PCL) and heparinized nano-fluorohydroxyapatite for cancellous bone tissue engineering. The research investigated the impact of heparinized nano-fluorohydroxyapatite particles on چکیده کاملThe primary purpose of this study is to produce a composite scaffold using polycaprolactone (PCL) and heparinized nano-fluorohydroxyapatite for cancellous bone tissue engineering. The research investigated the impact of heparinized nano-fluorohydroxyapatite particles on various properties of the scaffold, including water absorption, biodegradability, and alkaline phosphatase activity. The scaffold was produced using the phase separation (solid-liquid) method in combination with freeze-drying, and two different concentrations of heparinized nano-fluorohydroxyapatite powder were utilized. Biodegradability was assessed by submerging the scaffolds in phosphate-buffered saline for 6 weeks, showing that increased nano-fluorohydroxyapatite content enhanced biodegradability. PCL/10%w(H-nFHA50) exhibited the highest biodegradability rate. Water absorption analysis revealed that PCL scaffolds had lower water absorption compared to composite samples with heparinized nano-fluorohydroxyapatite, with PCL/10%(H-nFHA50) demonstrating the highest water absorption. Alkaline phosphatase activity was assessed on day 14 of cell culture, showing higher activity in heparinized samples compared to heparin-free samples in the presence of nano-fluorohydroxyapatite. The presence of heparin and nano-fluorohydroxyapatite in the scaffold structure likely contributed to this difference. No significant difference was observed between heparinized scaffolds with different nano-fluorohydroxyapatite concentrations. The results emphasize that the constructed scaffolds possess the potential for utilization in cancellous bone tissue engineering. پرونده مقاله -
دسترسی آزاد مقاله
5 - بررسی پارامترهای موثر برمقاومت فشاری، مقاومت الکتریکی ویژه و جذب آب بتن متخلخل سبک
شهریار غلامین نوویرسر مرتضی جمشیدی رحمت مدندوستبتن متخلخل نوعی ویژه از بتن سبک با اسلامپ کم یا حتی صفر شناخته میشود که از سیمان، درشت دانه، درصد محدودی از ریز دانه (یا فاقد ریزدانه)، افزودنیهای مختلف شیمیایی و پوزولانی تشکیل شده است. دراین مقاله از لیکای سازهای با وزنحجمی m3kg/ 750 و نسبت آب به سیمان ثا چکیده کاملبتن متخلخل نوعی ویژه از بتن سبک با اسلامپ کم یا حتی صفر شناخته میشود که از سیمان، درشت دانه، درصد محدودی از ریز دانه (یا فاقد ریزدانه)، افزودنیهای مختلف شیمیایی و پوزولانی تشکیل شده است. دراین مقاله از لیکای سازهای با وزنحجمی m3kg/ 750 و نسبت آب به سیمان ثابت (3/0W / C =) ، برای ساخت بتن متخلخل سبک استفاده شد و اثر نسبتهای مختلف سبکدانه به سیمان ( A/C ) شامل 3 ، 7/2 ، 4/2 ، 1/2 ، 8/1 ، 5/1 ، تخلخل کل و درصدحجمی خمیر سیمان بر روی مقاومت فشاری ، مقاومت الکتریکی ویژه و درصد جذب آب بتن متخلخل سبک درسن 28 روز مورد بررسی قرار گرفت. با افزایش نسبت A/C از 5/1 تا 3، حجم خمیر سیمان از 873/30 % به 436/15 % در نمونهها کاهش و تخلخل کل از64/21 % به 08/38 % افزایش یافت که منجر به کاهش مقاومت الکتریکی ویژه از 45/11 به 841/6 ، کاهش مقاومت فشاری از Mpa 27/13 به MPa 37/4 و افزایش جذب آب از 185/11 % به 695/12 % در نمونه های بتن متخلخل سبک شد. نتایج این پژوهش بهبود ویژگیهای فیزیکی و افت ویژگیهای مکانیکی و دوام بتن متخلخل سبک حاوی لیکا را نشان دادند. پرونده مقاله -
دسترسی آزاد مقاله
6 - Experimental Investigation of Strength and Water Absorption of Concrete Containing Desert Sand
Amir Hamzeh Keykha Jalal NajmaddiniThe purpose of this study is to investigate the effect of desert sand as a replacement on the tensile and compressive strength of concrete. To this end, a total of 180 cubic specimens (15×15×15 cm) and 90cylindricalspecimens (15×30 cm) were made with t چکیده کاملThe purpose of this study is to investigate the effect of desert sand as a replacement on the tensile and compressive strength of concrete. To this end, a total of 180 cubic specimens (15×15×15 cm) and 90cylindricalspecimens (15×30 cm) were made with three concrete classes of C20, C25, and C30. Control samples (samples without desert sand) and samples containing 5%, 10%, 15%, and 25% sand were also produced. They were processed in mineral-free water at 7, 14, 21, and 28 days. They were then subjected to pressure and tension tests by a 200-ton digital concrete breaker jack. For the water absorption test, 15 cylindrical samples (7.5×15 cm) were made for C25 and 0%, 5%, 10%, 15%, and 20% desert sand. They were then tested after 28 days. The results showed that the compressive strength at the age of 28 days gradually increased by adding the sand. It reached the highest for C20 containing 10% sand. However, it reached the highest foe C25 and C30 containing 5% sand. Adding sand over 20% leads to decreasing compressive strength. The tensile strength of C25 and C30 concrete containing 5% sand and C20 concrete containing 10% sand was the highest compared to the control sample. Adding sand up to 10% leads to decreased water absorption, and then it increases after adding sand. پرونده مقاله -
دسترسی آزاد مقاله
7 - Effect of Natural Pozzolan on Concrete’s Mechanical Properties and Permeability in Various Grades of Cement
Farhad Pirmohammadi Alishah Mehdi Mohammad RazaeiPozzolan is an additive to cement clinker that if added to the high quality cement and concrete, it can be effective in enhancing the quality of cement and concrete resulting from high quality controlled precision and repeated sampling and continuous testing. Concrete c چکیده کاملPozzolan is an additive to cement clinker that if added to the high quality cement and concrete, it can be effective in enhancing the quality of cement and concrete resulting from high quality controlled precision and repeated sampling and continuous testing. Concrete creates the cement-free concrete without any additives. Documentary reports and rigorous scientific studies have shown that good pozzolan can, in addition to increasing the chemical resistance of concrete, eliminate the defects caused by the use of conventional cement in concrete and due to the diversity of water and soil use in different areas. In this study, the effect of natural pozzolan in different grades of cement on the mechanical properties and permeability of concrete at 7 and 28 days of age is investigated. It was found that with increasing cement grade, the water absorption rate of concrete increased. Also, the effect of pozzolan on the permeability of concrete samples is increased by increasing the pozzolan water absorption rate. Also, the effect of cement grade on the compressive strength of concrete was found to decrease with increasing concrete grade. Today using alternative sources in concrete productions is important, due to its economical and environmental considerations. Pozzolans are one of these resources which decrease the environmental pollutions and production costs of concrete structures. پرونده مقاله -
دسترسی آزاد مقاله
8 - Influence of nano graphene on water absorption in polyester/vinylester blend gel coats
Zeinab Rajabtabar Morteza Ehsani Azam Ghadami Yasser AmaniWater absorption characteristics of composite materials and gel coats are crucial for their applications in marine industry. The physical and mechanical properties of composite parts are influenced by moisture. Water absorption of five gel coat compositions based on epo چکیده کاملWater absorption characteristics of composite materials and gel coats are crucial for their applications in marine industry. The physical and mechanical properties of composite parts are influenced by moisture. Water absorption of five gel coat compositions based on epoxy vinylester resin and neopentylglycol unsaturated polyester resin and their blends was studied in this work. The influence of nanographene addition on the water absorption of these gel coats was also investigated. The results showed that epoxyvinylester resin had the lowest and neophentylglycol unsaturated polyester resin had the highest water absorption levels, and their blends, as expected, showed the same behavior. TEM, SEM and XRD were used to analyze and characterize the dispersion and distribution of nanographene particles in the polymer matrices. The results showed both dispersed and non-dispersed flakes in the polymer matrices. It was also shown that the addition of nanographene resulted in gel coats with lower water absorption levels. پرونده مقاله -
دسترسی آزاد مقاله
9 - Application of Nanoscience in Self-cleaning Properties of Concrete Facade for Development of Sustainable Environment
Sayedeh Fatemeh Khoshkalam Soleimandarabi Raheleh rostami Mehdi NezhadnaderiUsing mineral admixtures in cement composites as a way to improve their mechanical and sustainable environmental properties is a common practice in concrete technology. Among them nano-silica effectively influences the composite's early and long-term properties. In this چکیده کاملUsing mineral admixtures in cement composites as a way to improve their mechanical and sustainable environmental properties is a common practice in concrete technology. Among them nano-silica effectively influences the composite's early and long-term properties. In this study, the effect of different percentages of TiO2 (0, 2.5 and 5 %) on self-cleaning properties and water absorption of cement composites containing nano-silica were investigated. according to the use of different cementitious material (nano-silica) and TiO2 in mix proportions, to obtain mixtures with a desirable workability, superplasticizer was added in different volume percentages.Better size distribution and pore refinement lead to a denser cement matrix with low porosity which in turn considerably lower the water absorption of the cement composites. the maximum final water absorption according to ASTM C497 is 9% for method A and 8.5% for method B. Comparsions of water absorption tests as a result of adding of TiO2 and nano-silica in concrete show that the maximum final water absorption is 4.9% in N1 design mixture and the minimum final water absorption is 4.3% in N2 design mixture.The incorporation of TiO2 has positively affected the results for nano-silica containing specimens. A decrease of 6.5% and 11.1% between N1 and N3 respectively shows the positive effect of TiO2 on decrease of water absorption. The results show that TiO2 along with nanosilica has great potential for improving the environmental and self- cleaning properties of concrete facades of buildings in cities exposed to high levels of cleanliness. پرونده مقاله -
دسترسی آزاد مقاله
10 - بررسی پارامترهای موثر برمقاومت فشاری، مقاومت الکتریکی ویژه و جذب آب بتن متخلخل سبک
شهریار غلامین نوویرسر مرتضی جمشیدی رحمت مدندوستبتن متخلخل نوعی ویژه از بتن سبک با اسلامپ کم یا حتی صفر شناخته می¬شود که از سیمان، درشت دانه، درصد محدودی از ریز دانه (یا فاقد ریزدانه)، افزودنی¬های مختلف شیمیایی و پوزولانی تشکیل شده است. در¬این مقاله ¬از لیکای ¬سازه¬ای ¬با¬ وزن¬حجمی m3¬¬¬kg/ 750¬ و نسبت آب به سیمان ثا چکیده کاملبتن متخلخل نوعی ویژه از بتن سبک با اسلامپ کم یا حتی صفر شناخته می¬شود که از سیمان، درشت دانه، درصد محدودی از ریز دانه (یا فاقد ریزدانه)، افزودنی¬های مختلف شیمیایی و پوزولانی تشکیل شده است. در¬این مقاله ¬از لیکای ¬سازه¬ای ¬با¬ وزن¬حجمی m3¬¬¬kg/ 750¬ و نسبت آب به سیمان ثابت (3/0W / C =) ، ¬برای ساخت بتن متخلخل سبک استفاده شد و ¬اثر ¬نسبتها¬ی مختلف سبکدانه به سیمان ( A/C ) شامل 3 ، 7/2 ، 4/2 ، 1/2 ، 8/1 ، 5/1 ، تخلخل کل ¬و درصدحجمی خمیر سیمان بر روی مقاومت فشاری ، مقاومت الکتریکی ویژه و درصد جذب آب بتن متخلخل سبک درسن 28 روز مورد بررسی قرار گرفت. با افزایش نسبت A/C از 5/1 تا 3¬، حجم خمیر سیمان از 873/30 % به 436/15 % در نمونه¬ها کاهش و تخلخل کل از64/21 % به 08/38 % افزایش یافت که منجر به کاهش مقاومت الکتریکی ویژه از 45/11 به 841/6 ، کاهش مقاومت فشاری از Mpa 27/13 به MPa 37/4 و افزایش جذب آب از 185/11 % به 695/12 % در نمونههای بتن متخلخل سبک شد. نتایج این پژوهش بهبود ویژگیهای فیزیکی و افت ویژگیهای مکانیکی و دوام بتن متخلخل سبک حاوی لیکا را نشان دادند. پرونده مقاله
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