Showing 7 results for Aminzadeh
Volume 12, Issue 3 (summer 2021)
Abstract
Hyaluronic acid (HA) is a natural and linear polymer that finds a wide-range of applications in medicine, cosmetics, and nutraceuticals because of excellent viscoelasticity, high moisture retention capacity, high biocompatibility and non-toxicity. HA has been recently produced in industrial scale by Streptococcal species. Streptococci are nutritionally fastidious lactic acid bacteria and cannot synthesize some amino acids. Therefore, it is necessary to study and select some commercial culture media for their growth. In this study, HA production and hyaluronidase activity of S. zooepidemicus ATCC 43079 in three culture media were investigated. Regarding the detrimental effect of this enzyme on HA amount, 6-O-Palmitoyl-L-ascorbic acid as hyaluronidase inhibitor was added to culture medium during fermentation. The effect of three variables consisted of glucose concentration, yeast extract concentration and medium pH each at 3 levels were considered and (response surface methodology (RSM) was used for statistical design of experiments to study the HA production by this strain. The results showed that maximum HA production was obtained when glucose concentration, yeast extract concentration and pH were 21.2 g L-1, 43.6 g L-1 and 6.6, respectively. Under optimum conditions, HA was produced as 370±15 mg L-1 which was ~150% more than of HA concentration in basal medium (150±10 mg L-1) and productivity reached 56.74 g L-1 h-1 that was increased 2 fold compared to central point.
Volume 15, Issue 2 (5-2008)
Abstract
The protection of fundamental human rights at the time of war or peace is an obligation that should be observed at anytime by the states and international organizations. After the Second World War, the non-peaceful situations such as occupation and economic sanctions have occurred numerously, which in some cases lasted for more than a decade. Unfortunately, the laws governing these situations are not implemented properly, and therefore fundamental human rights of people, especially their life, integrity and security, have been violated. This article aims at considering legal rules and their effectiveness in protecting fundamental human rights at the times of occupation and economic sanctions. This study is based primarily on the conventional and customary international legal rules.
Mahtab Aminzadeh, Ali Safavinejad, Seyed Alireza Zolfaghari,
Volume 16, Issue 5 (7-2016)
Abstract
In the present study, the effect of high temperature radiant heaters’ arrangement on providing appropriate and uniform thermal conditions under asymmetric flow field have been investigated in an industrial environment. For this reason, a sample industrial environment with one inlet and outlet opening has been considered with two different types of high temperature radiant heaters’ arrangement: single radiant heater and couple radiant heaters. For the mentioned conditions, continuity equation, momentum equations, energy equation and radiative transfer equations have been solved by OpenFoam numerical solver. Also energy consumption has been evaluated in the present study. The results show that in presence of asymmetric flow field, using couple high temperature radiant heaters in comparison with single radiant heater causes more uniform temperature distribution and decrease about 10 degrees of Celsius in maximum temperature of floor. Also, this can cause to decrease about 35 percent in floor temperature distribution deviation from the average appropriate temperature (27 degrees of Celsius). Moreover, the results indicate that utilizing couple high temperature radiant heaters leads to increase in energy consumption about 10 percent in comparison with single radiant heater.
Seyed Alireza Zolfaghari, Hamed Bayazi, Mahtab Aminzadeh, Ali Foadaddini,
Volume 16, Issue 13 (Conference Special Issue 2017)
Abstract
Mahtab Aminzadeh, Ali Safavinejad, Seyed Alireza Zolfaghari,
Volume 16, Issue 13 (Conference Special Issue 2017)
Abstract
A. Aminzadeh, A. Safari, A. Parvizi,
Volume 19, Issue 9 (September 2019)
Abstract
Due to higher demands for tailor welded blanks (TWBs) applications in the transportation industry, it is important to understand their forming characteristics in manufacturing processes, especially the deep drawing, in order to produce products with higher qualities. Due to differences between the base materials strength as well as the existence of the welding zone, the formability of TWBs is frequently less than the base metals. The aim of this study is the comparison of weld line displacement and drawing depth in TWBs designed and produced by laser welding and friction stir welding. Laser welding is more appropriate for TWBs production comparing to the other welding processes because of the creation of limited heat affected zone and suitable keyhole. The parameters of the friction stir welding process are very important due to having a high influence on complicated plastic zone variation, the material flow pattern and temperature distribution in TWBs sheets. In this paper, by design experiments, the effect of blank holder force and linear welding velocity on drawing depth and weld line displacement of TWBs have been investigated. Moreover, the harnesses of the weld zone in both processes have been examined. Results show that by increasing the linear velocity of laser welding, the amount of weld line displacement and drawing depth will be increased. Furthermore, the higher linear velocity of friction stir welding will result in the higher weld line displacement and drawing depth. Likewise, the harnesses of the laser welding zone are higher than those ones for friction stir welding zone.
Volume 27, Issue 2 (Summer 2023)
Abstract
Although the issue of water rights and especially shared waters has been very important for a long time, But during the transition from the traditional structure, the importance of adhering to the requirements in this field has doubled. The problem of investigating on the allocation of shared waters in the European region due to the large population and lack of resources and in the African region due to the fact that a significant part of these resources has remained unused, has gained great importance and its inappropriate allocation has led to discrimination and deprivation of many people which has affected other dimensions of human rights. In order to solve this challenge and achieve the main goal, i.e. the realization of justice for all members of the human society, the legislative and judicial approach governing the two regions of Africa and Europe regarding the principle of cooperation governing the allocation of shared waters have been analyzed and through matching among them, the strengths and weaknesses of each one has been revealed. Therefore, solutions have been presented to provide good governance and the reasonable and fair allocation of these resources in accordance with the existing social realities in each land which can be applied to other areas that are facing this problem and prevented the occurrence of disputes in this area or the disputes that have occurred continuously resolved peacefully
