نتایج جستجو برای: irrigation channel embankment and hydraulic conductivity coefficient

تعداد نتایج: 16898008  

Journal: :Tree physiology 2008
Daniel Taylor Derek Eamus

We studied relationships among branch hydraulic conductivity, xylem embolism, stomatal conductance (gs), foliar nitrogen (N) concentration and specific leaf area (SLA) of seven tree species growing at four temperate woodland sites spanning a 464-1350 mm rainfall gradient. Specifically, we examined the question: are gs and foliar N concentration coordinated with branch hydraulic conductivity and...

Journal: :تحقیقات آب و خاک ایران 0
حجت احمدی استادیار گروه آب دانشگاه ارومیه حسین رضایی دانشیار گروه آب دانشگاه ارومیه کامران زینالزاده استادیار گروه آب دانشگاه ارومیه

seepage analysis through earth dams is employed to determine the water loss. moreover, as the magnitude of pore pressure in dam body is calculated using seepage analysis, this analysis plays an important role on the stability analysis in these types of structures. as the hydraulic conductivity of the earth dam materials, is considered as one of the effective parameters on the magnitude of seepa...

Journal: :Tree physiology 2014
Peter Hajek Christoph Leuschner Dietrich Hertel Sylvain Delzon Bernhard Schuldt

Trees face the dilemma that achieving high plant productivity is accompanied by a risk of drought-induced hydraulic failure due to a trade-off in the trees' vascular system between hydraulic efficiency and safety. By investigating the xylem anatomy of branches and coarse roots, and measuring branch axial hydraulic conductivity and vulnerability to cavitation in 4-year-old field-grown aspen plan...

2014
H. M. A. Rashid K. Kawamoto

This study investigated the combined effect of temperature and single-species salt solutions on geotechnical properties (swell index and liquid limit) and hydraulic conductivity of bentonite applying different cation types, concentrations, and temperatures. Results showed that both the swell index and the liquid limit decreased with an increase in salt concentration irrespective of the type of ...

Journal: :آب و خاک 0
صالح ریاحی علی رضا وطن خواه

introduction: side weir structures are extensively used in hydraulic engineering, irrigation and environmental engineering, and it usually consists of a main weir and a lateral channel. side weirs are also used as an emergency structure. this structure is installed on one side or both sides of the main channel to divert the flow from the main channel to the side channel. lateral outflow takes p...

2016
Ahmet E. Osmanlioglu

In this study, natural bentonite was used as natural clay material and samples were taken from the Kalecik district in Ankara. In this research, bentonite is the subject of an analysis from standpoint of assessing the basic properties of engineered barriers with respect to the buffer material. Bentonite and sand mixtures were prepared for tests. Some of clay minerals give relatively higher hydr...

In the Manning equation the hydraulic radius can be defined as the cross-section dimension of the shape. In pipe flow the bed shear stress is assumed to be uniformly distributed along the wetted perimeter which cannot be true in open channel flow. Hence, three approximation of the true boundary shear-stress distribution are examined and more practical conveyance depth or resistance radius formu...

2005
MELVIN T. TYREE MARTIN H. ZIMMERMANN

In this paper we report measurements concerning the conductivity of water and ions and the interaction between the two in excised pieces of xylem of red maple stems under various conditions. We have also demonstrated that it is possible to detect the flow of solutions through the stems of maple by measuring the degree of interaction between the flow of water and ions. In this technique we apply...

Journal: :آب و خاک 0
مهرداد شریعتی غلامعباس صیاد عبدالرحمن برزگر زهرا درویش پسند

abstract disc infiltrometer is one of those devices that used in recent years in measurement of hydraulic conductivity of entire soil. in order to analyze the data taken by disc infiltrometer a variety of methods based on wooding’s base analyze have been introduced. the objective of this study was to compare the performances of ankeny and weir methods for predicting soil hydraulic properties us...

2009
Volker Stiller

We investigated the role of hydraulic conductivity, wood density, and xylem cavitation in the response of baldcypress (Taxodium distichum) seedlings to increased soil salinity and drought. One-year-old, greenhouse-grown seedlings were irrigated daily with a 100 mM (≈6‰) salt solution or once per week with fresh water (drought). Controls were irrigated daily with fresh water. Gas exchange rates ...

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