Search results for "texture"
showing 10 items of 402 documents
Influence of environmental factors on the spatial distribution and diversity of forest soil in Latvia
2012
This study was carried out to determine the spatial relationships between environmental factors (Quaternary deposits, topographical situation, land cover, forest site types, tree species, soil texture) and soil groups, and their prefix qualifiers (according to the international Food and Agricultural Organization soil classification system World Reference Base for Soil Resources [FAO WRB]). The results show that it is possible to establish relationships between the distribution of environmental factors and soil groups by applying the generalized linear models in data statistical analysis, using the R 2.11.1 software for processing data from 113 sampling plots throughout the forest terri…
Spatial Distribution of Soil Hydrological Properties in the Kilombero Floodplain, Tanzania
2017
Analysis and interpretation of soil properties dynamics is a keystone in understanding the hydrologic responses and yield potential of floodplain wetlands. This study characterizes the distribution and spatial trends of selected soil physical properties in the Kilombero floodplain, Tanzania. A total of 76 composite soil samples were taken from 0 to 20 cm and 20 to 40 cm depth in a regular grid design across three hydrological zones, related to flooding intensity defined as fringe, middle, and riparian during the rainy season of 2015. The samples were analyzed for soil texture, bulk density, organic carbon, and saturated hydraulic conductivity. Seasonal soil moisture content was monitored at…
Factors Influencing Point Measurement of Near-surface Saturated Soil Hydraulic Conductivity in a Small Sicilian Basin
2017
Hydraulic conductivity of saturated soil, Ks, controls many hydrological processes. Parameterization of basin hydrological models in terms of Ks is complicated and uncertain owing to the very high spatial variability of this soil property. A small Sicilian basin was intensively sampled by the simplified falling head technique to obtain spatially distributed Ks data, and an attempt to explain their spatial variability on the basis of soil physical characteristics, digital elevation model-derived topographic attributes and land cover was carried out. High Ks values were obtained when clay content was low and both elevation and mean slope were high. Moreover, differences in Ks among land cover…
Estimating saturated soil hydraulic conductivity by the near steady-state phase of a Beerkan infiltration test
2017
Abstract Single-ring infiltration experiments carried out in the field, such as the Beerkan runs, allow easy and inexpensive characterization of soil hydraulic properties, and specifically saturated soil hydraulic conductivity, Ks, by maintaining the functional connection of the sampled soil volume with the surrounding soil. However, a single infiltration experiment is not enough to determine Ks. The simplest way to obtain the necessary additional data is based on the assessment of the soil texture and structure characteristics. In this investigation, a simplified method, named SSBI (Steady version of the Simplified method based on a Beerkan infiltration run), was developed to estimate Ks b…
Effect of soil and canopy factors on vegetation of Quercus robur woodland in the boreo-nemoral zone: A plant-trait based approach
2013
Abstract The aim of the study was to determine the effect of soil and canopy on the understory vegetation of Quercus robur stands in Latvia, located in the boreo-nemoral zone. To determine the main processes regulating formation of the plant communities, the understory vegetation of Q. robur stands was described using plant traits. Vegetation and soils were described in 24 plots representing contrasting soil types and tree species composition. Redundancy analysis was used to determine the relation between vegetation, described using plant traits (proportion of species with each trait), and soil and canopy factors. About 50% of the variation in vegetation described by plant traits was explai…
Wildland fire ash: Production, composition and eco-hydro-geomorphic effects
2014
Abstract: Fire transforms fuels (i.e. biomass, necromass, soil organic matter) into materials with different chemical and physical properties. One of these materials is ash, which is the particulate residue remaining or deposited on the ground that consists of mineral materials and charred organic components. The quantity and characteristics of ash produced during a wildland fire depend mainly on (1) the total burned fuel (i.e. fuel load), (2) fuel type and (3) its combustion completeness. For a given fuel load and type, a higher combustion completeness will reduce the ash organic carbon content, increasing the relative mineral content, and hence reducing total mass of ash produced. The hom…
Effects of solarisation on soil thermal-physical properties under different soil treatments: A review
2020
Solarisation technology allows for improving soil quality as well as crop productivity. The influence of the properties and method of use of plastic materials used to cover soils, such as the number and thickness of layers, and colour of the material, significantly alters soil thermal-physical properties. These effects can be managed and modified to increase solarisation efficiency by achieving a decrease in vapour movement between the soil surface and the atmosphere. Also, soil solarisation establishes microclimates that increase the effectiveness of fertilisers, thus modifying the soil thermal-physical properties. However, there is a lack of complete and general overview of this widely us…
Distance-based functions for image comparison
1999
The interest in digital image comparison is steadily growing in the computer vision community. The definition of a suitable comparison measure for non-binary images is relevant in many image processing applications. Visual tasks like segmentation and classification require the evaluation of equivalence classes. Measures of similarity are also used to evaluate lossy compression algorithms and to define pictorial indices in image content based retrieval methods. In this paper we develop a distance-based approach to image similarity evaluation and we present several image distances which are based on low level features. The sensitivity and eAectiveness are tested on real data. ” 1999 Published…
The use of linear regression methods and Pearson’s correlation matrix to identify mechanical–physical–chemical parameters controlling the micro-elect…
2008
Abstract Machining introduces residual stresses at the specimen surface and modifies the microstructure and the texture in a small volume close to the surface. Such changes are important in controlling the corrosion behaviour of machined workpieces in the presence of an aggressive environment. In the present paper, the relationships between cutting parameters and the surface and subsurface characteristics of machined copper were first quantified experimentally using a complete plan of L 8 (2 3 ) and a linear regression method. The influence of surface characteristics on the local polarisation curves of machined surfaces was then investigated. The shear-type crystallographic orientation gene…
Normal and mixed state Hall effect in (Hg0.9Re0.1)Ba2CaCu2O6+δ fully textured HTSC thin films
2004
Abstract Temperature and magnetic field dependence of the Hall effect in the normal and mixed state of fully textured (Hg0.9Re0.1)Ba2CaCu2O6+δ (HgRe-1212) HTSC thin films prepared by laser ablation deposition have been studied. The longitudinal resistivity ρxx and Hall resistivity ρyx of HgRe-1212 superconductor thin films were measured for a wide range of magnetic fields from 125 mT to 12 T with the field perpendicular to the ab plane and the current in the ab plane. A sign change of the Hall resistivity is observed in fields below 3 T in the region close to the superconducting onset temperature. The temperature dependencies ρxx ∝ T and ρyx ∝ 1/T have been observed for HgRe-1212 thin films…