نتایج جستجو برای: oven. measurement particles of dusts were done by a particle size distribution instrument

تعداد نتایج: 23705148  

Journal: :جنگل و فرآورده های چوب 0
کژال منوچهری دانشگاه تهران انوشیروان شیروانی دانشگاه تهران پدرام عطارد عضو هیات علمی دانشگاه تهران، دکتری یحیی خداکرمی مرکز تحقیقات کشاورزی و منابع طبیعی کرمانشاه

the ability of trees to trap dusts convinces their use for preventing the transport of dust over longer distances. this ability is increasingly important in threatened areas with dust invasion. the purpose of this study was to compare the size and distribution of particles deposited on the leaves surface of fraxinus rotundifolia, platanus orientalis, and robinia pseudoacacia trees, in paveh, we...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تبریز 1390

learning a second or foreign language requires the manipulation of four main skills, namely, listening, reading, speaking, and writing which lead to effective communication. it is obvious that vocabulary is an indispensible part of any communication, so without a vocabulary, no meaningful communication can take place and meaningful communication relies heavily on vocabulary. one fundamental fac...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی اصفهان - دانشکده فیزیک 1390

in this thesis, barium ferrite nano particles were prepared by sol-gel method. their structural and magnetic properties of samples have been investigated using thermo gravimetric analysis (tg-dta), x-ray powder diffractometer (xrd), fourier transform infrared (ftir), scanning electron microscopy (sem), field emission scanning electron microscopy (fesem), ac susceptometer, vibrating sample magne...

پایان نامه :0 1370

all analytical methods are generally based on the measurement of a parameter or parameters which are somehow related to the concentration of the species.an ideal analytical method is one in which the concentration of a species can be measured to a high degree precision and accuracy and with a high sensitivity. unfortunately finding such a method is very difficult or sometimes even impossible.in...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد گرمسار - دانشکده ادبیات، زبانهای خارجی و تاریخ 1389

abstract the main purpose of this study was to investigate whether there was any significant difference between the speaking achievement of learners who were trained by means of consciousness raising of sociolinguistic skills and that of learners who were trained without the above mentioned task. the participants of this study consist of 60 intermediate level students participating languag...

پایان نامه :دانشگاه تربیت معلم - سبزوار - دانشکده علوم انسانی و پایه 1393

burnout is a response to the chronic work stress which is prevalent mostly among the people who do people job, like teaching. the purpose of this study was to develop a valid and reliable instrument that can measure burnout in foreign language teachers. although some widely used instruments were developed before which measured burnout in teachers, a specific instrument which include specific sy...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه اراک - دانشکده علوم 1392

the history of plant’s used for mankind is as old as the start of humankind. initially, people used plants for their nutritional proposes but after the discovery of medicinal properties, this natural ?ora became a useful source of disease cure and health improvement across various human communities. berberis vulgaris is one of the medicinal plants used in iranian traditional medicine. berberis ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تهران 1370

the subjects of the study are only the tefl teachers and students at gilan university. to obtain the desired data, a questionnaire which was based on the theories and disecussions gathered, was used as the main data gathering instrument. to determine the degree of relationship between variables, covariance and pearson product moment correlation coefficient were the formulas applied. the data we...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور مرکز - دانشکده شیمی 1391

dendrimer synthesis strategies now provide virtual control of macromolecular nanostructures as a function of size and surface/interior functionality. these strategies involve the covalent assembly of hierarchical components reactive monomers , branch cells or dendron’s around atomic or molecular cores according to divergent/convergent dendrite branching principles.combinon of two or more dendri...

Fasih-Ramandi, Fatemeh , Jafari, Mohammad-Javad , Khodakarim, Soheila , Sadigzadeh, Asghar ,

Introduction: Determining the size distribution of the particles for assessing their effects on human health and their control mechanisms is very effective. One of the most important equipment used in determining particle size distribution is the DMA. In this study, in addition to the design and construction of a DMA, the size distribution measurement of aerosol particles was carried out. Mate...

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