Javadi Y.,Islamic Azad University at Damghan
Journal of Pressure Vessel Technology, Transactions of the ASME | Year: 2015
Welding of nickel-based alloys is increasingly used in the industry to manufacture many important components of the marine industries, chemical processing, etc. In this study, a 3D thermomechanical finite element (FE) analysis is employed to evaluate residual stresses and deformations caused by the tungsten inert gas (TIG) welding of Monel 400 (Nickel-Copper alloy) plates. The FE results related to the residual stresses and deformations have been verified by using the hole-drilling stress measurement and common dimensional measurement tools, respectively. Residual stresses analyzed by the FE simulation are then compared with those obtained from ultrasonic stress measurement. The ultrasonic stress measurement is based on acoustoelasticity law, which presents the relation between the acoustic waves and the stress of material. The ultrasonic stress measurement is carried out by using longitudinal critically refracted (LCR) waves which are longitudinal ultrasonic waves propagated parallel to the surface inside the tested material. Two welded plates are experimentally prepared (with and without using clamp) to investigate the clamping effect on the welding residual stress and deformations. By utilizing the FE analysis along with the LCR method, the distribution of longitudinal residual stress could be achieved. It has been concluded that the applied methodologies are enough accurate to distinguish the clamping effect on the welding residual stresses and deformations of Monel plates. Copyright © 2015 by ASME.
Jokar M.,Islamic Azad University at Damghan |
Abdul Rahman R.,University Putra Malaysia
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2014
Colloidal silver nanoparticles were prepared via chemical reduction using polyethylene glycol (PEG) as a reducing agent, stabiliser and solvent. Silver polyethylene nanocomposites were produced via two methods, namely: melt blending and layer-by-layer (LBL) deposition of silver nanoparticles onto a polyethylene film. The silver ion release from either melt-blended or LBL-deposited nanocomposites into a food simulant and apple juice during 30 days at 4°C and 40°C was determined by atomic absorption spectroscopy. The effects of incorporating or coating of silver nanoparticles, silver concentration, contact media, temperature and time on silver ion migration were evaluated using factorial design. The diffusion coefficients of silver ions into the food simulants and apple juice were calculated using the Miltz model. The results indicated that the production method of nanocomposite, silver concentration, temperature, time and contact media showed a significant effect (p < 0.05) on silver ion migration. The quantity of silver ion migration from the nanocomposites into the food simulants and apple juice was less than the cytotoxicity-level concentration (10 mg kg-1) in all cases over 30 days. The coating of silver nanoparticles, higher silver concentration in the nanocomposite, higher temperature and acidic property of contact liquid all promoted the silver ion release from the nanocomposite films. The migration of silver ions from nanocomposites obeyed first-order diffusion kinetics. © 2014 Taylor & Francis.
Mozaffari Nejada A.S.,Islamic Azad University at Damghan
Acta Horticulturae | Year: 2012
Export of agriculture products has an important role in non-petroleum export and has specific significance among the agriculture product of pistachio, its export from Iran going to parts of the world since 2500 years ago. Pistachio figures prominently among other nuts due to its nutritious value. Pistachio trees are the second plant (after date) that can be alive for a long time without water. Until 1979, Iran was the only unique exporter of pistachio that entered into the world market through offering the pistachios product of California with competitive qualification and use of facilities. According to the latest statistics released by the World Food and Agriculture Organization (FAO) affiliated to the United Nations, the pistachio production in the world stood at 548,759 metric tons (MTs) in 2002, Iran ranking first with a production of 300,000 MTs. The pistachio gardens in Iran's rival country, the US occupies a total area of 44,000 hectares vs. 280,000 hectares in Iran. Aflatoxin is one of the serious problems in pistachio industries, some pistachios have suitable conditions for growth of fungus within the fruit, which are the basis of aflatoxin, because of different reasons, the most important of them being splitting of the external green layer of the fruit and maybe with aflatoxin. Therefore maximum levels for aflatoxin should be determined. In this study, weather conditions for pistachio planting, provinces that are planting pistachio in Iran and statistics of pistachio production in these provinces, kinds of pistachio existing in Iran, statistic study of Iran pistachio export during a few years using valid resources and strategies to increase Iran pistachio export in global markets are discussed.
Nafchi A.M.,Islamic Azad University at Damghan |
Moradpour M.,Islamic Azad University at Damghan |
Saeidi M.,Islamic Azad University at Damghan |
Alias A.K.,Universiti Sains Malaysia
Starch/Staerke | Year: 2013
Thermoplastic starch (TPS) polymers were reviewed in this article. This review was categorized into the following studies: the role of starch as a thermoplastic polymer, transformation and melting mechanisms, plasticization and plasticizers, reactive extrusion (REX) and modifications, retrogradation, biodegradability, filler and blenders, and nano-particle incorporation in thermoplastic starch. This categorization allows us to understand the developments in this field in recent years and shows that the major challenges in the future are reducing sensitivity to moisture and retarding retrogradation of the thermoplastic matrix. Moreover, nano-particles such as clay can be used in TPS matrices to overcome these disadvantages. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Abbaspour H.,Islamic Azad University at Damghan
Russian Journal of Plant Physiology | Year: 2010
Salt stress is considered as one of the most important abiotic factors limiting plant growth and yield in many areas of the world. It has been shown that Vesicular Arbuscular Mycorrhizal Fungi (AMF) can alleviate this deficiency. The effects of AMF inoculation on growth variables and mineral nutrition of Carthamus tinctorius L. under salt stress condition were studied. Plants were grown in a sterilized, low-P sandy soil with Glomus etunicatum inoculum (10-12 spore/g soil) in a greenhouse. RLC (Root Length Colonized) percent was higher in control plants than treated ones with different salt concentrations. Shoot and root weights, height, the number of leaves, the number of lateral branches, and also leaf area of mycorrhizal (M) plants were higher than nonmycorrhizal (NM) ones in both controlled and salt-treated plants. P, Zn, Fe, Ca, K, Cu, and N contents in M plants were higher than in NM plants in control, low and medium salinity conditions, but Na content was lower in aerial parts of the M plants. The results showed a higher tolerance of inoculated M plants toward salt stress and their better growth. © 2010 Pleiades Publishing, Ltd.