نتایج جستجو برای: and groundwater levels control

تعداد نتایج: 17053899  

2003
David W. Watkins Daene C. McKinney David P. Morton

Groundwater is an important source of potable water because it is abundant and readily available in many locations and often requires little or no treatment. In 1995, groundwater accounted for approximately 20% of potable water use in the U.S., and approximately 50% of the U.S. population relied on groundwater for their source of drinking water. In most European countries, groundwater accounts ...

Groundwater drought denotes the condition and hazard during a prolonged meteorological drought when groundwater resources decline and become unavailable or inaccessible for human use. The aim of this study is to identify the influencial factors on groundwater drought in Hamadan- Bahar Watershed,Iran, to understand the forcing mechanisms. The Standardised Precipitation Index (SPI) has been used ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علوم کشاورزی و منابع طبیعی گرگان - دانشکده منابع طبیعی گرگان 1391

چکیده: در این تحقیق تأثیر ملاس که یکی از محصولات جانبی صنایع قند می باشد به عنوان یک افزودنی مقاومت خشک جدید در بهبود پالایش پذیری و ویژگی های فیزیکی و مکانیکی مقوای کنگره ای کهنه (occ) مورد بررسی قرار گرفته شد. بدین منظور پنج سطح ملاس( 0،5، 10، 15 و 18%) و سه سطح درجه روانی(420،400و320 میلی لیتر)به عنوان فاکتورهای متغیر در نظر گرفته شد و برای هر تیمار کاغذهای دست ساز با مساحت 2cm200 و وزن پای...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد گرمسار - دانشکده ادبیات و زبانهای خارجی 1391

this study was an attempt to investigate the effect of teaching meta cognitive strategies on iranian intermediate efl students speaking proficiency. in this study the researcher has employed metacognitive strategies taken from brown (2000) to teach speaking strategies to number of participants. the participants were intermediate students of shokouh language institute; they were divided into an ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه بیرجند 1388

a significant problem in multicarrier communication systems is the necessity to reduce the value of papr (peak-to-average power ratio) of transmitting signal. in this thesis we study the effect of the system parameters such as coding and modulation types on papr and ultimate ber in a mc-cdma system. in this study we consider fading channel as well as the nonlinearity of transmitter’s amplifier ...

Journal: :تحقیقات نظام سلامت 0
اصغر ابراهیمی مربی، گروه مهندسی بهداشت محیط، دانشکده بهداشت، دانشگاه علوم پزشکی یزد، یزد، ایران. محمد مهدی امین استادیار، مرکز تحقیقات محیط زیست، دانشگاه علوم پزشکی اصفهان، اصفهان، ایران حسن هاشمی عضو هیأت علمی گروه مهندسی بهداشت محیط، دانشکده بهداشت، دانشگاه علوم پزشکی شهرکرد، شهرکرد، ایران. رضا فولادی فرد کارشناس ارشد، گروه عمران محیط زیست، دانشکده فنی، دانشگاه تهران، تهران، ایران. مرضیه وحید دستجردی کارشناس ارشد، مرکز تحقیقات محیط زیست، دانشگاه علوم پزشکی اصفهان، اصفهان، ایران.

background: groundwater resources in arid and semi arid regions are very important. groundwater is contaminated by agricultural, industrial and municipal activity which as a result reduces its quality. investigating of the chemical quality of the groundwater is emphasized to identify pollutant environmental impacts associated with incorrect waste disposal practice. this research investigated th...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علامه طباطبایی - دانشکده ادبیات و زبانهای خارجی 1389

abstract tasks nowadays are at the center of attention in sla research. task types is one of the critical issues in this regard, their effectiveness and suitability to any particular context, their characteristics and the result they yield are among some of these issues. on the other hand, discourse markers (dms) have been very much investigated and their effectiveness in conveying the meaning...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد تهران مرکزی - دانشکده ادبیات و زبانهای خارجی 1390

abstract the current study set out to address the issue as to whether the implementation of portfolio assessment would give rise to iranian pre-intermediate efl learner autonomy. participants comprised 60 female in pre-intermediate level within the age range of 16-28.they were selected from among 90 language learners based on their scores on language proficiency test -key english test. then, t...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه اراک - دانشکده ادبیات و علوم انسانی 1393

this study investigates the effect of teacher’s repetition as an input enhancement technique in explicit teaching of vocabulary items on efl learners’ later retrieval. to this end, 66 persian speaking english learners, aged 18 - 29, homogenized through a standard proficiency test (opt), were chosen and put into two experimental and control groups, each 33 learners. general service list (gsl), a...

پایان نامه :0 1374

this experimental study has been conducted to test the effect of oral presentation on the development of l2 learners grammar. but this oral presentation is not merely a deductive instruction of grammatical points, in this presentation two hypotheses of krashen (input and low filter hypotheses), stevicks viewpoints on grammar explanation and correction and widdowsons opinion on limited use of l1...

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