نتایج جستجو برای: flow control structures

تعداد نتایج: 2147635  

The hybrid AC-DC microgrid (HMG) architecture has the merits of both DC and AC coupled structures. Microgrids are subject to intermittence when the renewable sources are used. In the HMG, since power fluctuations occur on both subgrids due to varying load and unpredictable power generation from renewable sources, proper voltage and frequency regulation is the critical issue. This article propos...

Journal: :آب و خاک 0
سید علی موسوی ابراهیم امیری تکلدانی محمدهادی داودی

abstract rockfill dams are a type of hydraulic control structures used to protect river bed in cases where a considerable reservoir volume is available behind these structures; it could mitigate the floods and provide a gradual depletion of incoming volume of water so that the discharge passing downstream is decreased. one of the main issues on utilizing rockfill dams is to keep its permeabilit...

Aliasghar Montazar Mahmoud Mashaal Mina Sadat Seyedjavad

Measuring sensitivity of hydraulic structures is considered as an approach for evaluation of water projects performance, due to lower distribution efficiency in Irrigation and Drainage project schemes. Sensitivity analysis approach for irrigation structures is one of flow analysis methods which are developed in recent years in order to measure the behavior of flow in hydraulic structures in an ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان - دانشکده مهندسی عمران 1391

deployable scissor type structures are composed of the so-called scissor-like elements (sles), which are connected to each other at an intermediate point through a pivotal connection and allow them to be folded into a compact bundle for storage or transport. several sles are connected to each other in order to form units with regular polygonal plan views. the sides and radii of the polygons are...

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

this study compared the different effects of form-focused guided planning vs. meaning-focused guided planning on iranian pre-intermediate students’ task performance. the study lasted for three weeks and concentrated on eight english structures. forty five pre-intermediate iranian students were randomly assigned to three groups of guided planning focus-on-form group (gpfg), guided planning focus...

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...

اشرف السادات شکرباغانی, , علی اکبر بیدختی, ,

 Layered structures in the oceans have always attracted the attention of oceanographers. The formation of these structures have been attributed to phenomena such as double – diffusive convection, internal waves and turbulent modulated mixing .In this paper, the vertical structures of temperature, salinity, density and the layered structure in the middle parts of Caspian Sea have been studied. C...

Journal: :تحقیقات مهندسی کشاورزی 0
جمال محمد ولی سامانی دانشیار گروه سازه های آبی دانشگاه تربیت مدرس رضا فرشاد دانشجوی کارشناسی ارشد سازه های آبی دانشگاه تربیت مدرس

pure rockfill dams have been found specific attention in watershed management and flood control, recently. in addition to hydraulic specific features, one of the important advantages of these structures is their consistency with nature and environment. normally, floods are accompanied with high sediment loads which may enter the body of dam. when flow through dam body governed by hydraulic grad...

Journal: :مرتع و آبخیزداری 0
بیتا شیروی دانشجوی کارشناسی ارشد آبخیزداری، دانشکدة منابع طبیعی و محیط زیست دانشگاه فردوسی مشهد علی گلکاریان استادیار دانشکدة منابع طبیعی و محیط زیست دانشگاه فردوسی مشهد علی ابوطالبی پیرنعیمی کارشناس ارشد زمین‏شناسی، دانشکدة منابع طبیعی و محیط زیست دانشگاه فردوسی مشهد

check dams, are small dams in the watershed. these dams are constructed in susceptible areas to erosion due to reduce of flow velocity and erosion, control of sediment and flood in upstream of reservoir dams. these structures are made using wood, stone and cement, and gabion. these structures change the hydrological response of the watershed by reducing flow velocity, the channel slope and stor...

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