نتایج جستجو برای: silt and sand

تعداد نتایج: 16833811  

Journal: :Journal of Hydrology and Hydromechanics 2023

Abstract The presence of gravel in soils modifies the porosity, pore connectivity and size distribution soil matrix as well matrix-gravel interfaces. aim present study is to investigate effect relative volume samples with mass fractions 5,10, 20 wt% varying bulk densities (1.3, 1.45, 1.55, 1.60, 1.65 g cm –3 ) on (i) total field capacity, plant available water holding (ii) (iii) thermal capacit...

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

به منظور بررسی تغییرات جمعیت اسپورهای قارچی میکوریز وزیکولار _ آربوسکولار در خاک، تعیین درصد کلونیزاسیون ریشه، همبستگی این دو با فاکتورهای فیزیکوشیمیایی خاک و همچنین شناسایی نوع همزیستی میکوریزایی، جنگلهای ارسباران در منطقه کلیبر از استان آذربایجان شرقی انتخاب شد. نمونه برداری از ریشه و خاک ریزوسفری 23 گونه گیاهی در فواصل زمانی خرداد و مرداد از محدوده ریزوسفری گیاهان به عمل آمد. نمونه برداری کا...

Mohammad Ali Adibi Mohammad Jafari Mohammad Zadbar Seyed Akbar Javadi Somayeh Naseri

One of the ordinary methods to protect, rehabilitate, and enhance an ecosystemfunction in arid and semi-arid areas of the world is sand dune stabilization using biologicalpractices. Plantation of species on the soil plays a great role in sustainable management ofthe ecosystem. This research studies the effects of cultivation of Haloxylon ammodendronand Atriplex canescens on physical-chemical ch...

2002
Bryan R. Becker Anil Misra Brian A. Fricke

Soil thermal conductivity is significantly influenced by saturation and dry density. In this paper, a family of empirical correlations are presented which relate soil thermal conductivity to saturation for five soil types, namely, gravel, sand, silt, clay and peat, in both the frozen and unfrozen states. These correlations were developed from a soil thermal conductivity database which was const...

2002
Eugene F. Stoermer E. F. Stoermer

Natural benthic substrates were collected beneath the ice of Grand Traverse Bay by divers on March I0, 1978 as part of a seasonal investigation of northern Lake Michigan benthic algae assemblages. Some of the samples from each selected depth between the surface and 32 m were examined using SEM. Natural substrates (silt, sand, pebbles, algae, shells) were field-fixed in glutaraldehyde, dehydrate...

Journal: :Geomechanics and geophysics for geo-energy and geo-resources 2023

Abstract The increase of pore water pressure under a dynamic load is an important reason for the vibration liquefaction saturated sand. Therefore, studying model tailings sand plays role in seismic analysis ponds. In this paper, development characteristics fine and silt pond with centerline method are studied by triaxial tests. research results show that ratio shows trend "rising–smooth–rising"...

2003
C. P. Holliday Todd C. Rasmussen William P. Miller

This laboratory work examines the relationship between turbidity (NTU) and total suspended sediment concentration (TSS, mg/L) for a Cecil Ap soil, a common Southeastern Piedmont soil type. We show a 1:1 correlation between NTU and TSS for the silt and clay fractions, but a smaller ratio for clay and bulk-soil samples. These results suggest that NTU measurements can be used to estimate sediment ...

Journal: :مرتع و آبخیزداری 0
محسن پادیاب دانشجوی دکتری آبخیزداری دانشکدة منابع طبیعی، دانشگاه تهران سادات فیض نیا استاد دانشکده منابع طبیعی دانشگاه تهران حسن احمدی استاد گروه آبخیزداری، دانشگاه آزاد اسلامی واحد علوم و تحقیقات تهران اردشیر شفیعی عضو هیئت علمی مرکز تحقیقات کشاورزی و منابع طبیعی استان کهکیلویه و بویراحمد

small precipitation with temporal and spatial variation of rainfall is the main responsible factors on flood occurrence in arid and semi arid regions. floods in their regions usually contain high concentration of sediments which when they are deposited on the surface of lands, they change the properties of soils of the area. in this research, the effect of floodwater spreading on physic-chemica...

2016
Ying Pan Hao Zhang Xu Li Yonghong Xie

Sedimentation is recognized as a major factor determining the ecosystem processes of lake beaches; however, the underlying mechanisms, especially in freshwater sand dunes, have been insufficiently studied. To this end, nine belt transects from nine freshwater sand dunes, classified into low (<23.7 m), medium (25.4-26.0 m), and high-elevation groups (>28.1 m) based on their elevations in 1972, w...

Journal: Desert 2007
G. Feghhi H. Ahmadi M. Ekhtesasi N. Mashhadi, S. Feiznia

Wind regime and sand grain size are two of the factors that determine the morphology and dynamics of sand dunes in desert areas. Regarding the importance of wind effects on sand dunes especially in Iran, in this study, Khartooran Erg was analyzed to determine wind direction and to detect sand source sites. Khartooran Erg is located on eastern north of Iran and lies in Khorasan Razavi and Semnan...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید