نتایج جستجو برای: a total of 158 composite surface soil samples 0

تعداد نتایج: 23502732  

Journal: :Journal of environmental sciences 2007
Hong-yan Zhang Ru-tai Gao Yuan-fang Huang Xiao-hong Jia Shu-ren Jiang

The spatial variability in the concentrations of 1,2,3,4,5,6-hexachlorocyclohexane (HCH) and 1,1,1-trichloro-2,2-bis-(p-chlorophenyl) ethane (DDT) in surface soils was studied on the basis of the analysis of 131 soil samples collected from the surface layer (0-20 cm depth) of the alluvial region of Beijing, China. The concentrations of total HCHs (including alpha-, beta-, gamma-, and delta-isom...

ژورنال: علوم آب و خاک 2012
حسن احمدی, , فرود شریفی, , کاظم نصرتی, ,

Sediment sources fingerprinting is needed as an autonomous tool for erosion prediction, validation of soil erosion models, monitoring of sediment budget and consequently for selecting soil conservation practices and sediment control methods at the catchment scale. Apportioning of eroded-soil into multiple sources using natural tracers is an integrated approach in soil erosion and sediment studi...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه ارومیه 1377

the methods which are used to analyze microstrip antennas, are divited into three categories: empirical methods, semi-empirical methods and full-wave analysis. empirical and semi-empirical methods are generally based on some fundamental simplifying assumptions about quality of surface current distribution and substrate thickness. thses simplificatioms cause low accuracy in field evaluation. ful...

Journal: Desert 2006
F. Sarmadian H. Matinfar, S. Alavipanah

This study determined some spectral characteristics and relationship between Landsat spectral reflectance and soil surface color in the arid region of Iran (Kashan). The study carried out in the kashan area that covers 90000 ha. Consisting of mountain, hills and flood plain. Enhanced Thematic Mapper (ETM+) data collected on July 2002 were used for this research. The color composite images produ...

Journal: Desert 2017
D. Hoffmeister F. Khormali, J. Mohammadi M. Bagheri Bodaghabadi M. Kehl S. Maleki

The effects of geological conditionwere assessed on density of Soil Organic Carbon (SOC) and Nitrogen (N)in a sequence of hillslope landscape, derived from different lithology i.e. loess deposit, reworked loess, marl with mixed siltstone and shale, reddish brown clay deposits and older loess in the semiarid area of northern Iran. However, other factors can influence SOC and N density such as la...

Journal: :journal of rangeland science 2013
hossein purghaumi sayed jamaledin khagehedin reza jaafari ali purghaumi

soil organic matter has positive consequences eht rof quality and productivityof soil and also environment, agricultural and biological sustainability and conservation ofbiodiversity and soil. organic matter plays an important role in the physical and chemicalprocesses of soil and thus, it is of a great effect on the spectral characteristics of soil. thisstudy was done in order to develop the m...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی (نوشیروانی) بابل - دانشکده مهندسی مکانیک 1389

due to the limiting workspace of parallel manipulator and regarding to finding the trajectory planning of singularity free at workspace is difficult, so finding a best solution that can develop a technique to determine the singularity-free zones in the workspace of parallel manipulators is highly important. in this thesis a simple and new technique are presented to determine the maximal singula...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه خلیج فارس - دانشکده مهندسی 1393

in civil engineering concrete is a material combined of hydraulic cement, sand, gravel and water. gravel and sand compose 60 to 70 percent of concrete. these aggregates support compression force of concrete. cement paste acts as glue to stick grain together. in bushehr factories producing aggregates do not operate according to astm standards, so that fineness modulus (fm) of the produced sands ...

Journal: :journal of rangeland science 2015
afshin sadeghirad mohamad nasrollahi hossein azarnivand mohamad ali zare chahoki

plant litter is an important factor for soil conservation and sustainability that could modify soil chemical properties and increase the plant biomass production. the aim of this research was to compare plant litter chemical composition and its effects on soil properties in three species including hordeum bulbosum, poa bulbosa, bromus tectorum. first, soil samples were taken in the depth of 0-3...

ژورنال: علوم آب و خاک 2015
امینی, میترا, فرقانی, اکبر,

Any change in the characteristics of air, soil, water and food that adversely affect the health of the ecosystem, activities of human and other organismsis called contamination. Heavy metal uptake by plants depends on the type and concentration of metalin soil, its bioavailability, and plant species. The use of new sciences such as geostatistics is useful for fast and simple determination of so...

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