نتایج جستجو برای: hydraulic flow unit

تعداد نتایج: 877519  

Journal: :Tree physiology 2002
Robert M Hubbard Barbara J Bond Randy S Senock Michael G Ryan

Recent studies have shown that stomata respond to changes in hydraulic conductance of the flow path from soil to leaf. In open-grown tall trees, branches of different heights may have different hydraulic conductances because of differences in path length and growth. We determined if leaf gas exchange, branch sap flux, leaf specific hydraulic conductance, foliar carbon isotope composition (delta...

Journal: :international journal of agricultural science, research and technology in extension and education systems 2012
elham sirjani majid mahmoodabadi

soil detachment is known as an important process in soil erosion and its quantification is necessary to establish a basic understanding of erosion. this study was carried out to find the best flow erosivity indicator(s) for predicting detachment rate at low slopes. for this purpose, 12 experiments including 6 flow discharges (75, 100, 125, 150, 175 and 200 ml/s) and 2 slope gradients (1.5 and 2...

Journal: :Plant physiology 1984
J W Radin M P Eidenbock

Suboptimal levels of phosphorus (P) strongly inhibited leaf expansion in young cotton (Gossypium hirsutum L.) plants during the daytime, but had little effect at night. The effect of P was primarily on cell expansion. Compared to plants grown on high P, plants grown on low P had lower leaf water potentials and transpiration rates, and greater diurnal fluctuations in leaf water potential. Hydrau...

 Investigation of ecological, hydrological status and habitat Suitability of river is one of the key elements in river ecosystem management. In this regard, in the present study, in order to evaluate the ecological sustainable conditions in Zarrin-Gol River of Golestan Province, during stepwise calculations, echo-hydraulic and hydromorphocological analysis of the habitat of Capoeta gracilis (Ke...

2008
M. Berli A. Carminati T. A. Ghezzehei

[1] Prediction of water flow and transport processes in soils susceptible to structural alteration such as compaction of tilled agricultural lands or newly constructed landfills rely on accurate description of changes in soil unsaturated hydraulic conductivity. Recent studies have documented the critical impact of aggregate contact characteristics on water flow rates and pathways in unsaturated...

محمد محمدی, , مهدی یاسی, ,

  A labyrinth spillway is an overflow spillway to regulate and control flow in canals, rivers and reservoirs. The main hypothesis for the development of such a spillway is to increase the discharge per unit width of structure for a given headwater. This type of structure is often an efficient alternative to a gated-spillway type where either the increase of the flood-passage capacity or the con...

Journal: :کشاورزی (منتشر نمی شود) 0
محمود مشعل استادیار گروه آبیاری، پردیس ابوریحان، دانشگاه تهران، پاکدشت، تهران دیوید ج. بال دانشیار گروه عمران، دانشگاه منچستر، منچستر، انگلستان

complex culverts have a change of section (transition) at one or more positions along their lengths. the hydraulic performance cannot be estimated using simple culvert methods because the transition may change the control point. by modeling the flow through a transition as free flow, sluice flow, pipe flow and treating a complex culvert, as a series of simple culverts with the appropriate hydra...

2014
Yingguang Chu Vilmar Æsøy Houxiang Zhang Oyvind Bunes

This paper presents a modeling approach based on Bond Graph (BG) method for offshore hydraulic crane focusing on its hydraulic system characteristics. A hydraulic library is built in the modeling software tool 20-sim using BG elements. The hydraulic submodels are designed according to one specific type of offshore crane, however, they can be easily modified and reused for other similar systems....

2005
Rachel Hutchinson Robert W. Nairn

Vertical flow systems (VFS) are a type of passive treatment unit process in which acid mine drainage (AMD) flows vertically through layers of organic matter and limestone. Located in the coal belt of eastern Oklahoma, the Red Oak VFS was constructed to address AMD exiting an abandoned underground coal mine. The passive treatment system consists of five cells, alternating between surface flow (c...

2014
L Y He Z W Wang S Kurosawa

The causes of resonance of a certain model pump-turbine unit during startup process were investigated in this article. A three-dimensional full flow path analysis model which contains spiral case, stay vanes, guide vanes, runner, gaps outside the runner crown and band, and draft tube was constructed. The transient hydraulic excitation force of full flow path was analyzed under five conditions n...

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