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دسترسی آزاد مقاله
1 - A new form of Grad-Shafranov equation for a tokomak with an elongated cross section
Alireza Seife Khajeh Marjan Samad SobhanianAbstractDifferent forms of the well-known Grad-Shafranov (G-S) equations that define the equilibrium behavior of tokomak plasma have been already obtained. None of these equations contain explicitly the triangularity δ and the elongation ratio ks. The aim of this work i چکیده کاملAbstractDifferent forms of the well-known Grad-Shafranov (G-S) equations that define the equilibrium behavior of tokomak plasma have been already obtained. None of these equations contain explicitly the triangularity δ and the elongation ratio ks. The aim of this work is to obtain a new form of G-S equation which includes both the triangularity and the elongation ratio. For verifying the correctness of the obtained equation, the triangularity is set to 0, which leads to a G-S equation for circular cross section. Also, the magnetic field and current density obtained from this new G-S equation is reduced to the quantities already derived for circular cross section. پرونده مقاله -
دسترسی آزاد مقاله
2 - Optimization of the Ductile Properties of an Arc Welded Plate Based on the Yield Strength, Elongation and Modulus of Elasticity.
Samuel Sada Joseph AcheboAs a means of controlling the setback associated with the ductile properties of the welded joint, the optimal ductile properties of a mild steel weld were studied based on empirical data generated using the metal inert gas (MIG) welding process with specific references چکیده کاملAs a means of controlling the setback associated with the ductile properties of the welded joint, the optimal ductile properties of a mild steel weld were studied based on empirical data generated using the metal inert gas (MIG) welding process with specific references to the yield strength, percentage elongation, poisson ratio and modulus of elasticity using the Response Surface Methodology (RSM) and Genetic Algorithm (GA). The results judging from the remarkable quality of the ductility of the weld reveals the adequacy of the yield strength, poisson ratio, and percentage elongation as key determinant in ascertaining the ductility of a weld as against the tensile strength which have been widely used in previous studies. Further analysis to determine the optimal ductile properties using the optimization techniques generated two different results which were further compared by means of a confirmatory test. The GA results recorded a more accurate optimal responses compared to the RSM having a yield strength of 270.28N/mm2, 31.01% percentage elongation, 0.359 poisson ratio, and modulus of elasticity of 1660.3N/mm2. The results not withstanding their differences reveals that manufacturers can obtain the optimal ductile weld properties using the GA and RSM techniques if the right combination of process parameters is made. پرونده مقاله -
دسترسی آزاد مقاله
3 - Mechanical properties of sago starch film incorporated with phycocyanin extract of Spirulina platensis
Fatemeh Sadeghi Erimi Masoumeh Hosseinzadeh Sadegh SalmanpourThe mechanical and barrier properties of sago starch film incorporated with different percentage of phycocyanin(0.2, 0.4, 0.6, 0.8 and 1.0) were evaluated. With regard to mechanical properties, tensile strength and Youngs modulusdecreased when the percentage of extract چکیده کاملThe mechanical and barrier properties of sago starch film incorporated with different percentage of phycocyanin(0.2, 0.4, 0.6, 0.8 and 1.0) were evaluated. With regard to mechanical properties, tensile strength and Youngs modulusdecreased when the percentage of extract Elongation at break (%) increased. and increased with increasing percentage ofextract from 0.2 to 0.1. پرونده مقاله -
دسترسی آزاد مقاله
4 - Characterization of the mechanical properties of the sago polymer films incorporated with the Abelmoschus esculentus extract nano Zinc-oxide and nanozincoxide-cadmium
Majedeh Mansourian, Masoumeh Hosseinzadeh* Ali MirabiSago starch polymer is widely used in food, pharmaceutical, textile, etc industries. Their combination with other materials such as sorbitol and glycerin increases their mechanical properties. Mechanical properties are important for edible films. Mechanical tests of the چکیده کاملSago starch polymer is widely used in food, pharmaceutical, textile, etc industries. Their combination with other materials such as sorbitol and glycerin increases their mechanical properties. Mechanical properties are important for edible films. Mechanical tests of the films were performed in accordance to the standard methods. In this regard, the use of various herbal extracts can greatly improve the efficiency of the packaging.In the research biofilm based on the sago starch incorporated with the Abelmoschus esclentus alcoholic extract (2, 4, and 6 grams) and Sorbitol/glycerol was used as a plasticizer and films were prepared under controlled conditions by the casting method using nano zinc oxide and nano zincoxide -Cds5% its properties the mechanical tensile strength (TS) and elongation at break (EAB) and mechanical properties were evaluated with a decrease in the content of the extract. The best results for the concentration of 2gram extract mixed with 0.01gram nanoparticle zinc oxide-Cds5%. Which is the lowest tensile strength and highest elongation at break. پرونده مقاله -
دسترسی آزاد مقاله
5 - Characterization of the mechanical properties of sago polymer films incorporated with the Flax seed extract, nano Zinc-oxide and nanozinc oxide-cadmium
Mohammad Mohammadi Masoumeh Hosseinzadeh Sadegh SalmanpourToday, the tendency to use biodegradable packaging, including coatings and edible films, is increasing day by day in the industry due to the fact that they are free from synthetic chemicals and do not cause environmental pollution. In this regard, the use of combination چکیده کاملToday, the tendency to use biodegradable packaging, including coatings and edible films, is increasing day by day in the industry due to the fact that they are free from synthetic chemicals and do not cause environmental pollution. In this regard, the use of combinations of plant extracts can greatly improve the efficiency of this type of packaging. The purpose of this research is to investigate the effect of alcoholic extracted from flax seed on the mechanical properties of sago starch edible film. In the research biofilm based on sago starch incorporated with the flax seed alcoholic extract (2, 4, and 6) grams , using nano zincoxide and nano zincoxide-Cds5% its property the mechanical Tensile strength(TS) and Elongation at break (EAB) and mechanical properties were evaluated with an increase in the content of the extract. The best results for the concentration of 6gram extract mixed with 0.01gram nanoparticle zinc oxide-Cds5%. Which is the lowest tensile strength and highest elongation at break. پرونده مقاله -
دسترسی آزاد مقاله
6 - Drought effects on elongation kinetics and sugar deposition in the elongation zone of durum wheat (Triticum durum Desf.) leaves
Mostefa Touati Abdelkrim Kameli Benalia Yabrir Benziane Adli Elhadi BeziniThe aim of this study was to analyze the effect of drought stress on the kinetics of leaf elongation in relationship to the variation of sugar concentrations and their net deposition rates along the elongation zone of leaf 4 of durum wheat plants. Plants were grown in s چکیده کاملThe aim of this study was to analyze the effect of drought stress on the kinetics of leaf elongation in relationship to the variation of sugar concentrations and their net deposition rates along the elongation zone of leaf 4 of durum wheat plants. Plants were grown in soil in a naturally illuminated greenhouse, and water was withheld from seedlings for a period of 14 days. Leaf 4 of 26 day-old plants was used for growth measurements and tissue sampling. Relative elemental growth rates (REGR), cell displacement velocity (DV), and elongation zone length (EZL) were significantly reduced by drought treatment. Together, this resulted in a decrease in leaf elongation rate (LER) in drought-stressed plants. Epidermal cell length along the elongation zone was not significantly affected by drought stress, indicating that the decrease in elongation zone length was due mainly to a reduction in cell production rate. The concentration of total soluble sugars (TSS) and non-reducing sugars (NRS) was highest at the leaf base and decreased distally from 10 mm from the leaf base in plants grown under non-stressed (control) conditions. Drought stress caused a significant accumulation of TSS at the leaf base, mainly through an increase in non-reducing sugars. The continuity equation was used to calculate sugar net deposition rates. Drought stress increased the net deposition rates of non-reducing sugars in the first 10 mm from the leaf base. This increase was the principal source for the increase in non-reducing sugars concentrations at the leaf base in response to drought. پرونده مقاله -
دسترسی آزاد مقاله
7 - Effect of Liquid Media and In Vitro Pre-acclimatization Stage on Shoot Elongation and Acclimatization of Date Palm (Phoenix dactylifera L.) cv. Najda
Mouaad Amine MazriThe effect of stationary liquid media to improve shoots elongation in date palm cv. Najda and an in vitro pre-acclimatization stage to increase the survival ercentage of plantlets in the greenhouse was investigated. Two basal liquid media were tested: full strength and چکیده کاملThe effect of stationary liquid media to improve shoots elongation in date palm cv. Najda and an in vitro pre-acclimatization stage to increase the survival ercentage of plantlets in the greenhouse was investigated. Two basal liquid media were tested: full strength and half strength Murashige and Skoog medium (MS). Media were devoid of plant growth regulators (PGRs), containing 0.5 mg/L 6-benzylaminopurine (BAP) or 0.5 mg/L indole-3-butyric acid (IBA) and 0.5 mg/L BAP. After three months of culture, all liquid media were efficient and allowed to overcome slow growth problem. The maximum shoot elongation was 11.3 cm, obtained in MS supplemented with 0.5 mg/L BAP and 0.5 mg/L IBA. The shoots were isolated and transferred either to the greenhouse or to one month in vitro pre-acclimatization stage in a PGRs-free solid medium (MS or MS/2) then to the greenhouse. A higher surviving rate (ranging from 70 to 86 %) was obtained after one month pre-acclimatization compared with the direct transfer to the greenhouse (12–28 %). پرونده مقاله -
دسترسی آزاد مقاله
8 - تحلیل رفتار مکانیکی-حرارتی نانوسیم طلا به روش دینامیک مولکولی
محمد طهماسبی پور ریحانه احمدی مهرزاد مدرسبا رشد و توسعه فزاینده علم و فناوری نانو، کاربرد نانو سنسورها، سیستمهای نانو الکترومکانیکی، سیستمهای نانوالکترونیکی و وسایل نانو فتونیکی رو به افزایش است. نانوسیمها به عنوان یکی از اجزاء کلیدی این سیستمها نقش قابل توجهی در عملکرد درست آنها دارند. بنابراین شناخت رف چکیده کاملبا رشد و توسعه فزاینده علم و فناوری نانو، کاربرد نانو سنسورها، سیستمهای نانو الکترومکانیکی، سیستمهای نانوالکترونیکی و وسایل نانو فتونیکی رو به افزایش است. نانوسیمها به عنوان یکی از اجزاء کلیدی این سیستمها نقش قابل توجهی در عملکرد درست آنها دارند. بنابراین شناخت رفتار مکانیکی- حرارتی نانوسیمها از اهمیت ویژهای برخوردار است. با توجه به مشکلات اجتنابناپذیر در انجام آزمایشهای تجربی بر روی نانوسیمها، از جمله نیاز به تجهیزات بسیار دقیق و پیشرفته و همچنین هزینه و زمان زیاد مورد نیاز برای انجام این آزمایشها، تعدادی از پژوهشگران به مدلسازی و شبیهسازی رفتار نانوسیمها پرداختهاند. شبیهسازی دینامیک مولکولی یکی از بهترین روشهای شناخت خواص نانوسیمها میباشد که در اغلب شبیهسازیهای نانو مقیاس از این روش استفاده میشود. با استفاده از روشهای شبیهسازی و مدلسازی می توان خواص نانوسیمها را با صرف هزینه اندک و زمان بسیار کوتاهی، در مقایسه با روشهای تجربی، به انجام رساند. در این مقاله، با هدف شناخت رفتار مکانیکی- حرارتی نانوسیم طلا، تاثیر دما ( 300، 450، 600 و 700 درجه کلوین) و نرخ کرنش (1/s 1082، 1/s 1092 و 1/s 10102) بر خواص مکانیکی نانوسیم از جمله منحنی تنش- کرنش، تنش تسلیم، تنش در لحظه شکست و میزان ازدیاد طول نانوسیم با قطر و طول به ترتیب 3 و 6 نانومتر به روش دینامیک مولکولی با استفاده از روش اتم جایگزین شده (پتانسیل EAM ) بررسی شده است. پرونده مقاله
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