نتایج جستجو برای: sediment concentration and distribution

تعداد نتایج: 16928187  

Journal: :مرتع و آبخیزداری 0
علی گلکاریان استادیار دانشکدة منابع طبیعی و محیط زیست دانشگاه فردوسی مشهد حسن احمدی هیات علمی بازنشسته دانشگاه تهران علی سلاجقه عضو هیات علمی دانشکده منابع طبیهی دانشگاه تهران محمد جعفری عضو هیات علمی دانشکده منابع طبیعی دانشگاه تهران علی شهبازی دانشجوی دکتری آبخیزداری دانشگاه تهران

erosion is one of the important factors in soil degradation and decrease fertility and slope length is one of the most effective factors in land form and amount of erosion. the objective of this study was investigation of spatially variation of sediment concentration in slope length until to receive transport capacity. to obtain this goal a hill slope simulator system designed and manufactured....

Journal: :Discrete Dynamics in Nature and Society 2022

Based on the advection-diffusion equation of suspended sediment, a general formula vertical distribution sediment concentration was derived by considering influence velocity. The new tested against over 3000 sets field data and obtained reasonable agreement. Comparing with Rouse concentration, accuracy increases significantly, shortcoming underestimation profile in practical application is revi...

Journal: :Applied and environmental microbiology 1980
T E Ward J I Frea

The direct fluorescent-antibody technique was employed to determine the distribution patterns of four species of methanogens in the sediments of Lake Erie and Cleveland Harbor. Methanobacterium ruminantium was the most numerous methanogen found in regions of high-organic-silt sediments. The population of this species ranged from 10 to 10 cells/g of dry sediment. Methanobacterium strain MoH and ...

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

درک الگوی توزیع مکانی ماکروفون خاک بدلیل اثرات آن روی فرآیندهای اکوسیستم بسیار مهم است. لیکن اطلاعات کمی در این خصوص وجود دارد. درمورد تنوع زیستی ارگانیسم ها وجانداران خاکزی که ازاجزای مهم وکلیدی درهرسیستم اکولوژیکی هستند و در بهبود حاصلخیزی خاک و تولیدات زمین وپایداری اکوسیستم ها(ازطریق فرآیندهای بیولوژیک)نقش عمده دارند تحقیقات کمی انجام شده است. این تحقیق جهت بررسی الگوی مکانی پارامترهای تنوع...

2010
David Werner Sarah E. Hale Upal Ghosh Richard G. Luthy

Traditional and new relationships of polychlorinated biphenyl (PCB) distribution among the solid phases, the free aqueous phase, and biolipids are comprehensively reviewed using seven well-characterized freshwater and marine sediments polluted with PCBs. The traditional relationship relating free aqueous concentration and biolipid concentration to sediment total organic carbon, compound octanol...

2014
Alice H. Nelson Paul R. Bierman Jeremy D. Shakun Dylan H. Rood

We use the concentration of in situ Be in quartz isolated from fluvial and morainal sand to trace sediment sources and to determine the relative contribution of glacerized and deglaciated terrain to Greenland’s sediment budget. We sampled along the western, eastern, and southern margins of the Greenland Ice Sheet, and collected sediment sourced from glacerized (n=19) and non-glacerized terrain ...

Journal: :iranian journal of radiation research 0
q.m. rashed-nizam department of physics, university of chittagong, chittagong-4331, bangladesh m. rahman department of physics, university of chittagong, chittagong-4331, bangladesh m.k. tafader institute of marine science, university of chittagong, chittagong -4331, bangladesh m. zafar institute of marine science, university of chittagong, chittagong -4331, bangladesh a.k.m.s.i. bhuian radioactivity testing and monitoring laboratory, bangladesh atomic energy commission, chittagong medical college campus, chittagong, bangladesh r.a. khan radioactivity testing and monitoring laboratory, bangladesh atomic energy commission, chittagong medical college campus, chittagong, bangladesh

to assess the environmental radioactivity levels and hence to determine the population exposure in kutubdia island, bangladesh the sediment samples were analyzed by using gamma ray spectrometry. in those sediment samples the average activity concentration of natural radionuclides 238u, 232th and 40k were found 15.39±1.67, 38.35±0.76 and 475.51±21.15 bq/kg respectively. the activity concentratio...

Rill erosion is considered to be the most important process affecting soils created by the concentrated flow of water. In this research to quantify sediment transport and runoff in natural rills, two rill experiments under dry and wet conditions were accomplished in November 2013 in the Golestan Dam. Filed experiments lead to a closer understanding of the dynamics and power of different soil er...

Journal: Geopersia 2019

Maharlu Lake, located in the SW of Iran, has acted as a sink for various wastewater discharges in the last few decades. This study aimed at assessing potentially toxic elements (PTEs) distribution in sediment, surface and pore water samples of Maharlu Lake. To achieve that, the samples were collected from each compartment and the total concentration of PTEs (Al, Fe, Sc, Cr, Co, Ni, Zn, As, Sb, ...

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