نتایج جستجو برای: geometric mean of soil particle diameter
تعداد نتایج: 21225289 فیلتر نتایج به سال:
The soil quality is defined as the ability of soil to function as an essential part of the human habitat. In this study, the effects of land use change (conversion of forest lands into agricultural lands) on the soil physical quality were studied in the Gilan-e-Gharb region. For this study, soil samples were collected from surface and subsurface layers of both land uses, and the peak and should...
investigating the feasibility of a proposed model for geometric design of deployable arch structures
deployable scissor type structures are composed of the so-called scissor-like elements (sles), which are connected to each other at an intermediate point through a pivotal connection and allow them to be folded into a compact bundle for storage or transport. several sles are connected to each other in order to form units with regular polygonal plan views. the sides and radii of the polygons are...
Petroleum pollution is an important environmental issue in most of the countries especially those have an oil industry. This study was conducted to investigate the effect of petroleum pollution on soil water repellency and its relation to soil structural stability in Bakhtiardasht area, Isfahan. Polluted and adjacent non-polluted locations were selected to be representative in the green space a...
estimating soil water retention curve using the particle size distribution based on fractal approach
introduction: water and soil retention curve is one of the most important properties of porous media to obtain in a laboratory retention curve and time associated with errors. for this reason, researchers have proposed techniques that help them to more easily acquired characteristic curve. one of these methods is the use of fractal geometry. determining the relationship between particle size di...
Introduction: Biological soil crusts are a community of cyanobacteria, fungi, lichens, and mosses and play key roles in arid and semi-arid regions including carbon and nitrogen accumulation, soil fertility, dust capture, soil conservation and stability. Recent studies show that the formation of biological soil crusts on mobile dunes areas is extremely difficult due to low vegetation cover, st...
This study presents measurements of size and time-resolved particle diameter growth rates for freshly nucleated particles down to 1 nm geometric diameter. Novel data analysis methods were developed, de-coupling for the first time the size and time-dependence of particle growth rates by fitting the aerosol general dynamic equation to size distributions obtained at an instant in time. Size distri...
Soil aggregate stability is an important indicator for controlling soil losses and can improve soil quality, particularly in an area such as the Loess Plateau. The objective of this study was to estimate the differences in soil aggregates across six different land-use systems (grassland, apple orchard, abandoned apple orchard, cropland maize, cropland wheat, and shrub-grassland). For this purpo...
The presence of Damghan Erg in West of Damghan Playa indicates high wind activity in this desert region. Due to technological advances and population growth in recent decades, large parts of past land uses have changed. These changes can exacerbate wind erosion and affect lands sedimentation. In this study, first, the land use maps of years 1974 and 2003 were prepared. The comparison of these m...
vegetation deterioration is a main cause of erosion and land degradation. therefore, land cover reclamation in the effected areas will affect erosion trend. in reclamation projects, the investigation of relationship between the planted species and soils is highly recommended. atriplex species can sequester carbon into soil, and have an ability to conserve soil and prevent soil erosion, as well....
background: the seeds of some medicinal plants and their compounds have long been valued for their numerous health benefits. objective:to investigate some physical and chemical properties of salvia spp. methods: some physico-chemical properties in five species of salvia seeds (consisted of s. officinalis l., s. macrosiphon l., s. hypoleuca l., s. sclarea l. and s. nemorosa l.) were measured at ...
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