نتایج جستجو برای: erosion control

تعداد نتایج: 1356155  

  Soil organic carbon (SOC) is a principal component in soil quality assessment. Knowledge of SOC and total nitrogen (TN) stocks are important keys to understand the role of SOC in the global carbon cycle and, as a result, in the mitigation of global greenhouse effects. SOC and TN stocks are functions of the SOC concentration and the bulk density of the soil that are prone to changes, influe...

Journal: :مرتع و آبخیزداری 0
کاظم نصرتی دانشیار دانشکدة علوم زمین دانشگاه شهید بهشتی فروزان احمدی دانشجوی دکتری ژئومورفولوژی - مدیریت محیطی، دانشگاه شهید بهشتی علی اکبر نظری سامانی دانشیار دانشکدة منابع طبیعی دانشگاه تهران محمد رضا ثروتی استاد دانشکدة علوم زمین دانشگاه شهید بهشتی

soil erosion is one of the most destructive phenomena which cause significant ecological changes in many areas. soil conservation and erosion control is essential because of the irreparable damage caused by soil erosion. soil conservation programs will not achieve until to find adequate methods of combating land degradation and ways to reduce the sediment. therefore, we need to have enough know...

2016
Fengpeng Han Lulu Ren Xingchang Zhang Zhanbin Li

In the Loess Plateau, soil erosion has not only caused serious ecological and environmental problems but has also impacted downstream areas. Therefore, a model is needed to guide the comprehensive control of soil erosion. In this study, we introduced the WEPP model to simulate soil erosion both at the slope and watershed scales. Our analyses showed that: the simulated values at the slope scale ...

2016
Degen Lin Hao Guo Fang Lian Yuan Gao Yaojie Yue Luis Loures

Water erosion causes reduced farmland productivity, and with a longer period of cultivation, agricultural productivity becomes increasingly vulnerable. The vulnerability of farmland productivity needs assessment due to long-term water erosion. The key to quantitative assessment is to propose a quantitative method with water loss scenarios to calculate productivity losses due to long-term water ...

2012
Ken L. Ferrier James W. Kirchner Robert C. Finkel

[1] Chemical weathering promotes regolith production, physical erosion, nutrient supply, and drawdown of atmospheric CO2. Although mineral dissolution rates show dependences on temperature and moisture in theoretical models and laboratory experiments, effects of climate on chemical erosion rates in nature remain uncertain, in part because variations in physical erosion rates and lithology can o...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس 1387

چکیده ندارد.

Journal: :Circulation. Cardiovascular imaging 2014
Zhao Wang Haibo Jia Jinwei Tian Tsunenari Soeda Rocco Vergallo Yoshiyasu Minami Hang Lee Aaron Aguirre James G Fujimoto Ik-Kyung Jang

BACKGROUND Recent reports show that plaque erosion can be diagnosed in vivo using optical coherence tomography in patients with acute coronary syndrome. However, quantitative optical coherence tomographic image criteria for computer-aided diagnosis of plaque erosion have not been established. METHODS AND RESULTS A total of 42 patients with acute coronary syndrome caused by plaque erosion were...

Journal: :تحقیقات جغرافیایی 0
محمود حبیب اللهیان دانشگاه حکیم سبزواری احمد نوحه گر دانشکده محیط زیست دانشگاه تهران علیرضا کمالی منابع طبیعی محمود حبیب اللهیان دانشگاه حکیم سبزواری معصومه رخبین پردیس دانشگاهی قشم دانشگاه هرمزگان احمد نوحه گر دانشکده محیط زیست دانشگاه تهران

â increase in wastage of soil resources in watershed is a persistent challenge that with increase in population and pressure on natural sources and unstable plantation on gradient farms and soils cause production reduces on farms, and also decrease in daily ratio of farms to population can cause more pressure on lands and natural resources.lavarefin watershed placed in 60 km from bandarabass in...

2015
Ioannis Kosmadakis Panagiotis Tsardaklis Konstantinos Ioannou George N. Zaimes

Soil erosion is one of the biggest global environmental problems. Finding new innovative systems to measure soil erosion more accurately is a priority. An effort is being carried out in this study to use automated electronics in order to systematically and accurately measure soil erosion. In addition, the frequent measurements taken will help collect a large amount of data on soil erosion. The ...

پایان نامه :وزارت بهداشت، درمان و آموزش پزشکی - دانشگاه علوم پزشکی و خدمات بهداشتی درمانی مشهد - دانشکده دندانپزشکی 1393

چکیده مقدمه: اختلالات مفصل گیجگاهی-فکی(tmd) به طور کلاسیک توسط گروهی از علایم کلینیکی شامل درد و صداهای مفصلی و محدودیت یا انحراف هنگام باز کردن دهان مشخص می شوند. هدف از این مطالعه بررسی ارتباط یافته های کلینیکی با تغییرات استخوانی در تصاویر cbct بیماران مبتلا به اختلالات مفصل گیجگاهی فکی (tmd)می باشد. مواد و روش کار: از میان مراجعه کنندگان به بخش پروتز دانشکده دندان پزشکی مشهد ، تعداد 41 ب...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید