نتایج جستجو برای: physical parameters

تعداد نتایج: 1195585  

Journal: :Journal of Research of the National Bureau of Standards Section A: Physics and Chemistry 1972

Increasing water demand and reducing its contaminations are the main concerns and challenges for water resource managers and planner due to its limited sources and high value. This study aims to assess and understand the factors which threaten the quality of groundwater resources and to achieve this, samples were taken from 14 active wells in District 3 of the Municipality of Tehran. After cate...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه بیرجند - دانشکده کشاورزی 1390

abstract this study is carried out to determine the chemical composition in the three vegetative stages of the haloxylon sp., degradation parameters, with adding naoh and ca(oh2 ). for this purpose, in may and october and january 2010 enough some haloxylon sp. of the ammary area was prepared. crude protein and ash percentage are decrease, neutral detergent fiber percentage with pragress stage ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده منابع طبیعی 1391

in this study, the effects of oleothermal modification on physical and mechanical peroperties of fir wood (abeis sp.) blocks were examined. at first, some blocks of fir wood with 5 × 20 × 120 cm dimensions were prepared. the blocks were treated in soybean oil. the effects of 3 factors such as treatments temperature (180and 200 °c), holding time (12 and 15 h) and initial moisture content of wood...

Journal: :تحقیقات نظام سلامت 0
سعید راثی نظامی دانشجوی دکتری، گروه مهندسی عمران- محیط زیست، دانشکده محیط زیست، دانشگاه تهران، تهران، ایران مهرداد نظری ها استادیار، گروه مهندسی محیط زیست، دانشکده محیط زیست، دانشگاه تهران، تهران، ایران اکبر باغوند دانشیار، گروه مهندسی محیط زیست، دانشکده محیط زیست، دانشگاه تهران، تهران، ایران علی مریدی - استادیار، گروه مهندسی منابع آب، دانشکده مهندسی آب و محیط زیست، دانشگاه صنعت آب و برق شهید عباسپور، تهران، ایران

background: the spread of urbanization in floodplains as well as increase of industrial and agricultural activities in river discharges may lead to water pollution by physical, chemical and biological pollutants. one of the major concerns in monitoring the water resources system is indentifying major quality parameters and determining a relationship between physical and chemical parameters. thi...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه بیرجند - دانشکده علوم 1391

in this thesis, we consider a mathematical model of cancer with completely unknown parameters. we study the stability of critical points which are biologically admissible. then we consider a control on the system and introduce situations at which solutions are attracted to critical points and so the cancer disease has auto healing. the lyapunov stability method is used for estimating the un...

Journal: :International Journal of Microwave and Wireless Technologies 2011

2013
Minghang Guo Jinshi Jian Zhun Zhao Juying Jiao

Rainfall erosivity factor (R) is one of the most commonly used factors in soil erosion models. While rainfall energy (E) is the most elementary physical parameter to predict R. Based on comparative analysis of previous soil erosion models and rainfall erosivity factor measuring methods, integrated application of modern photogrammetric techniques, image analytic methods and automatic control the...

1999
Thomas Kwok-keung Au Tom Yau-heng Wan

The Helfrich’s shape equation of axisymmetric vesciles is studied. A sufficient condition on the physical parameters and some geometric properties are discovered for the formation of biconcave shape vesicles. The study of the biconcave-discoid shape of a red blood cell has been a continued interest in the last two decades. Theoretically, the shape of the cell is to minimize a certain bending en...

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