Forensic comparison of soil samples: Assessment of small-scale spatial variability in elemental composition, carbon and nitrogen isotope ratios, colour, and particle size distribution

2006 ◽  
Vol 163 (1-2) ◽  
pp. 59-80 ◽  
Author(s):  
Kenneth Pye ◽  
Simon J. Blott ◽  
Debra J. Croft ◽  
James F. Carter
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Spatial Variability ◽  
Elemental Composition ◽  
Size Distribution ◽  
Nitrogen Isotope ◽  
Isotope Ratios ◽  
Soil Samples ◽  
Small Scale ◽  
Carbon And Nitrogen

scholarly journals Risiko des Eintrags von Phosphor in den Hallwilersee durch Bodenerosion

2015 ◽  
Vol 70 (3) ◽  
pp. 193-198 ◽  
Author(s):  
S. Müller ◽  
D. Schaub
Keyword(s):  
Particle Size ◽  
Soil Erosion ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Surface Waters ◽  
Aggregate Stability ◽  
Eutrophic Lake ◽  
Soil Samples

Abstract. An important factor in the release of phosphorus by soil erosion, with corresponding consequences on the quality of surface waters, is the formation of aggregates and their stability. Around the eutrophic Lake Hallwil six arable lands were examined in five repetitions regarding aggregate and particle size distribution, P-contents of the different fractions and aggregate stability. Central to this was the use of the setting column for fractionation of soil samples. In the case of Lake Hallwil the risk of phosphorus discharges by soil erosion seems low since the phosphorus is mainly bound in aggregates which are transported over short distances only. Thus other pathways (runoff from grassland, leaching via drains) may be more important.

Spatial Variability of Soil Particle-Size Distribution Heterogeneity in Farmland

2018 ◽  
Vol 61 (2) ◽  
pp. 591-601
Author(s):  
Jilong Liu ◽  
Lingling Zhang ◽  
Qiang Fu ◽  
Gaoqi Ren ◽  
Lu Liu ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Spatial Variability ◽  
Soil Properties ◽  
Size Distribution ◽  
Soil Particle ◽  
Soil Particle Size ◽  
Multi Scale ◽  
Soil Particle Size Distribution ◽  
Single Scale

Abstract. The objective of this research was to reveal the spatial variability of soil particle-size distribution heterogeneity. The farmland (48 m × 48 m) used in this study is located in the black soil region of northeast China and was divided into sixty-four 6 m × 6 m squares for sampling. The soil particle-size distribution was measured with a Mastersizer 2000. Soil particle-size distribution heterogeneity, the spatial variability of soil particle-size distribution heterogeneity, and the relationships between soil particle-size distribution heterogeneity and the clay, silt, and sand contents were studied by applying multifractal, geostatistical, and joint multifractal methods, respectively. The soil particle-size distribution had multifractal characteristics. Local information causing soil particle-size distribution heterogeneities were mainly low values of soil particle-size distribution; heterogeneities from the low-value side of the particle-size distribution were larger than those from the high-value side of the particle-size distribution. In the different soil layers, the degree of variation in soil particle-size distribution heterogeneities was moderate, with spatial correlation ranges of 37.82 m and moderate spatial dependences. At the single scale and multi-scale, the impacts of the clay, silt, and sand contents on the soil particle-size distribution heterogeneity changed with soil layer depth. The clay, silt, and sand contents had different degrees of influence on the spatial variability of soil particle-size distribution heterogeneity at the single scale and multi-scale. Multi-scale analysis could better reveal the degrees of influence of the above soil properties on the spatial variability of soil particle-size distribution heterogeneity. The results of this study enrich the knowledge of the spatial variability of soil properties and provide a reference and additional information for the quantitative characterization of soil particle-size distribution heterogeneity and soil management in this research area. Keywords: Geostatistics, Multifractal analysis, Relationship, Soil property.

scholarly journals CFD simulation of solids suspension in stirred tanks: Review

2010 ◽  
Vol 64 (5) ◽  
pp. 365-374 ◽  
Author(s):  
Aoyi Ochieng ◽  
Mrice Onyango
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Concentration Distribution ◽  
Cfd Simulation ◽  
Fluid Dynamic ◽  
Cfd Modeling ◽  
Small Scale ◽  
Stirred Tanks ◽  
Solids Concentration

Many chemical reactions are carried out using stirred tanks, and the efficiency of such systems depends on the quality of mixing, which has been a subject of research for many years. For solid-liquid mixing, traditionally the research efforts were geared towards determining mixing features such as off-bottom solid suspension using experimental techniques. In a few studies that focused on the determination of solids concentration distribution, some methods that have been used have not been accurate enough to account for some small scale flow mal-distribution such as the existence of dead zones. The present review shows that computational fluid dynamic (CFD) techniques can be used to simulate mixing features such as solids off-bottom suspension, solids concentration and particle size distribution and cloud height. Information on the effects of particle size and particle size distribution on the solids concentration distribution is still scarce. Advancement of the CFD modeling is towards coupling the physical and kinetic data to capture mixing and reaction at meso- and micro-scales. Solids residence time distribution is important for the design; however, the current CFD models do not predict this parameter. Some advances have been made in recent years to apply CFD simulation to systems that involve fermentation and anaerobic processes. In these systems, complex interaction between the biochemical process and the hydrodynamics is still not well understood. This is one of the areas that still need more attention.

scholarly journals Using Multi-Fractal and Joint Multi-Fractal Theories to Characterise the Spatial Variability of Soil Particle Size Distribution in an Underground Coalmine Area

2021 ◽  
Author(s):  
Sijia Li ◽  
Jinman Wang ◽  
Jiarui Zhang ◽  
Min Zhang
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Spatial Variability ◽  
Size Distribution ◽  
Coal Mining ◽  
Spatial Correlation ◽  
Land Reclamation ◽  
Mining Area ◽  
Fractal Method ◽  
Coal Mining Subsidence

Abstract Underground coal mining leads to serious surface deformation, which negatively affects the physical properties of soils Soil particle size distribution (PSD) is one of the most basic soil physical characteristic that influences other important properties such as soil hydraulics and thermodynamics. Understanding the spatial variability of the soil PSD in subsided land can provide targeted guidance for land reclamation. In this study, we conducted a quantitative study on the spatial variability of the soil PSD in the Pingshuo mining area on the Loess plateau, Shanxi Province in China, and explored the effects of subsidence and reclamation on the soil PSD. A plot experiment, including one unmined plot (UMP), one subsided plot (SUP), and one reclaimed plot (RCP), was performed in Anjialing No.3 underground coal mine in the, Pingshuo mining area. Four multi-fractal parameters of the soil PSD—D(0), D(1), Δα(q), and Δf(α)—were analyzed at the three sample sites. The joint multi-fractal method was carried out to analyze the spatial correlation of the soil PSD to further reveal the impacts of coal mining subsidence and land reclamation on the soil PSD. The multi-fractal method can reflect the local non-uniformity and heterogeneity of the soil PSD, while the joint multi-fractal approach can illustrate the correlation of the soil PSD between different soil depths. The range and spatial variability of the soil PSD increased due to coal mining subsidence and the impact of subsidence on the spatial disturbance of the surface soil PSD was greater than that of the deeper layers. The spatial correlation of clay in subsided land was larger than those of unmined land and reclaimed land, whereas, for silt and sand, the correlation was smaller. Land reclamation decreased the spatial variability of the soil PSD, which was near that of the unmined land after reclamation.

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