نتایج جستجو برای: aging time

تعداد نتایج: 1980703  

Journal: :transport phenomena in nano and micro scales 2013
m. shayesteh m. shafiee afarani a. samimi m. khorram

in this work, boehmite sol was prepared by a previously applied and validated method; hydrolysis of aluminum chloride hexa-hydrate. in order to obtain precise results, the effect of ph after adding precipitating agent, aging time, peptizing temperature and ultrasonic vibration time on the crystallite size of final precipitate were investigated in a narrow range. the preparation conditions appli...

CoHErrelation between weldability and improvement in properties is a key issue in materials science research. The objective of this work is to optimize the process parameters viz., aging temperature, aging time, solutionizing time, to enhance the hardness of Al6061 alloy. Hence, the present paper deals with hardness study of Tungsten Inert Gas welded 6061 aluminium alloy after age hardening und...

Journal: :نشریه دانشکده فنی 0
علی کریمی طاهری

in this paper, the effect of prestrain on strain aging of low carbon steels, in the temperatures of 100°c and 200°c and the aging time of 50 minutes, and also the effect of aging temperature on strain aging in a constant aging time and prestrain, are investigated. the results of experiments show that with increasing the amount of prestrain, the increase in yield stress and ultimate tensile stre...

Mehran Sharafizade Razieh Danaiee Far,

BACKGROUND: Seed aging is an important problem in developing countries which seeds stored in inappropriate condition. OBJECTIVES: Current research was carried out to study the effect of seed aging on quantitative parameters of wheat seeds (Chamran cultivar). METHODS: Experiment was carried out based on randomized complete block desi...

ژورنال: مواد پرانرژی 2019

In this article the aging of HTPB based composite solid propellants have been studied by Van’t Hoff method. The F-factor of Van’t Hoff equation was calculated by dynamic mechanical analysis (DMA) for reference propellants sample that was equal 2.5. Then the accelerated aging program conditions have been determined by Van’t Hoff equation. According to accelerated aging program the reference prop...

Journal: :به زراعی کشاورزی 0
الیاس سلطانی استادیار گروه علوم زراعی و اصلاح نباتات، پردیس ابوریحان، دانشگاه تهران، پاکدشت ـ ایران افشین سلطانی استاد گروه زراعت، دانشکده علوم زراعی، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، گرگان ـ ایران مصطفی اویسی استادیار گروه علوم زراعی و اصلاح نباتات، پردیس ابوریحان، دانشگاه تهران، پاکدشت ـ ایران

there are some computer programs to calculate germination related traits such as germin which have using problems. the aim of this work was to adjust germin for calculating germination related traits. seed aging effects on the seedling emergence was modeled using the optimized germin. this study was conducted based on completely randomized design in a factorial combination of five seeds aging t...

Journal: :iranian journal of materials forming 2014
m. kazeminezhad y. khaledzadeh a. karimi taheri

the static strain aging is a phenomenon that can change the mechanical properties of low carbon steels. thus, the static strain aging behavior of low carbon steel wires after drawing process is studied. to do so, the wires are austenitized at different temperatures and cooled in different rates. then the wires are drawn and aged at a specific temperature and time. before and after aging of each...

Journal: :caspian journal of chemistry 2013
seyed naser azizi abdolrauf samadi-maybodi mohammad hossein fatemi neda asemi

perlite or pearl stone is a natural glass which has formed by rapid cooling of viscous lava or magma. perlite is mainly composed of silica, aluminum, potassium and sodium. in this experiment, perlite was used as a low-cost source of si and al to synthesis of sodalite zeolite using the alkaline hydrothermal treatment. a statistical taguchi design of experiments was employed to evaluate the effec...

Journal: :علوم گیاهان زراعی ایران 0
اعظم زمانی سید احمد سادات نوری رضا توکل افشاری حمید ایران نژاد غلام علی اکبری افشین توکلی

an experiment was conducted to determine the aging mechanism in safflower seed using natural aging treatment (storing seed at room temperature for six years) and accelerated aging ( incubating the seed at 41?c and close to 100% relative humidity for 4 ,8 and 12 days). the results indicated that both natural and accelerated aging reduced germination percentage, seed vigor and activity of catalas...

In the current study, the sources of variation in the mean hardness value of heat treated aluminum 2024 samples were identified by using metallurgical study and design of experiment methodology (full factorial method). Hardness measurements and microstructural investigations of the samples were carried out using Brinell hardness test and optical microscopy, respectively. The effects of several ...

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