scholarly journals Anthropogenic impact on grain-size distribution and agrophysical properties of soils of cultivated rice lands of Kuban

2021 ◽  
Vol 262 ◽  
pp. 03006
Author(s):  
A.V. Osipov ◽  
V.N. Slyusarev ◽  
V.P. Vlasenko ◽  
I.I. Suminski
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Soil Density ◽  
Cultivated Rice ◽  
Physical Clay ◽  
Subsurface Soil ◽  
The Matrix ◽  
Agricultural Use ◽  
Soil Forming Processes

This work reviews the relation of the grain-size distribution and impact of the use of rice rotation soils on the main agrophysical indicators of soils that determine the composition and properties of soil cover of modern delta of Kuban. The regularities of dependence between the density of the matrix soil and the grain-size distribution that consist of mineral composition of alluvial soils and rocks have been identified. The trend towards increase in soil density with increase in physical clay and silt content, as well as increase in matrix soil density has been established. No significant differences in agrophysical properties of subsurface soil horizons and underlying formations have been identified. The agrophysical indicators of soils of rice fields and boharic analogues during their agricultural use have been assessed. The hydromorphic soil-forming processes did not lead to considerable changes in agrophysical properties of alluvial formations and soils involved in rice rotation.

Grain Size Distribution Effect on Mechanical Behavior of Nanocrystalline Materials

2004 ◽  
Vol 821 ◽  
Author(s):  
A.V. Sergueeva ◽  
N.A. Mara ◽  
A.K. Mukherjee
Keyword(s):  
Grain Size ◽  
Mechanical Behavior ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Nanocrystalline Materials ◽  
Tensile Deformation ◽  
Size Structure ◽  
Niti Alloy ◽  
Distribution Effect ◽  
The Matrix

AbstractGrain size distribution effect on the mechanical behavior of NiTi and Vitroperm alloys were investigated. Yielding at significantly lower stresses than found in equiaxed counterparts, along with well defined strain hardening was observed in these nanocrystalline materials with large grains embedded in the matrix during tensile deformation at temperatures of 0.4Tm. At higher temperature the effect of grain size distribution on yield stress was not revealed while plasticity was increased in 50% in NiTi alloy with bimodal grain size structure.

Effect of Vibrating Load on Grain Size Distribution of Crushed Rock Layer

2010 ◽  
Vol 168-170 ◽  
pp. 663-668
Author(s):  
Li Jun Yang ◽  
Wen Hui Bai ◽  
Bin Xiang Sun ◽  
Shuang Jie Wang ◽  
Jin Zhao Zhang
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Crushed Rock ◽  
Rock Layer ◽  
Fines Content ◽  
The Matrix ◽  
Study Laboratory ◽  
Permafrost Regions ◽  
Highway Embankment

For the construction of the proposed Qinghai-Tibet Express Highway in warm and ice-rich permafrost regions, it will be necessary to utilize the new technique of cooling the ground temperature by the coarsely crushed rock layer with a low fines content, instead of the traditional measures taken to increase simply thermal resistances, so as to protect from damage to highway embankment due to thaw settlement. The vibrating loads such as wheel load and tamping load may cause the breakage and abrasion of the matrix grains in the coarsely crushed rock layer. This results in decreasing of grain size and increasing of fines content in the crushed rock layer, thus decreasing the porosity of crushed rock layer. The smaller porosity of crushed rock layer may weaken the cooling effect of buoyancy-driven natural convection of the pore air in the crushed rock layer of the highway embankment, thus resulting in instability and failure of the embankment structure in permafrost regions. Under these conditions, the influence of vibrating load on the grain size distribution of the coarsely crushed rock layer has to be investigated experimentally. In the present study, laboratory experiments on the grain size variation of the coarsely crushed rock layer under vertically vibrating loads were carried out. The test results show that the vibrating load can cause the breakage and abrasion of the matrix grains in the coarsely crushed rock layer and the shapes of coarely crushed rock grain tend to be non-angular.

Homogeneous fabrication and densification of zirconia-toughened alumina (ZTA) composite by the surface-induced coating

1990 ◽  
Vol 5 (3) ◽  
pp. 615-622 ◽  
Author(s):  
Hyun M. Jang ◽  
Jong H. Moon
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Ionic Species ◽  
Colloidal Dispersion ◽  
Solution Interface ◽  
The Matrix ◽  
Electrochemical Phenomena ◽  
Selective Formation ◽  
Highly Uniform

This article proposes a new scheme for fabricating homogeneous Al2O3–ZrO2 composite, in which a thermodynamic theory of interfacial electrochemical phenomena is applied. The theory predicts that a heterogeneous Al2O3 interface in colloidal dispersion can induce an enhanced concentration of the ionic species needed for a selective formation of the ZrO2 precursor at the Al2O3/aqueous solution interface. Based on this proposition, a homogeneous Al2O3–ZrO2 composite powder was fabricated by a surface-induced coating of the fine ZrO2 precursor on the kinetically stable colloid particles of Al2O3. The composite prepared by the surface-induced coating was characterized by a uniform spatial distribution of the dispersed ZrO2 phase and by the absence of large ZrO2 grains formed from hard ZrO2 agglomerates. The composite also showed highly uniform grain size distribution of both the dispersed ZrO2 and the matrix Al2O3 phases. The uniform grain size distribution of the matrix phase indicates that the homogeneous coating of the fine ZrO2 particles is effectively pinning the Al2O3 grain boundaries.

Textural map units in quartzo-feldspathic mylonitic rocks

1987 ◽  
Vol 24 (10) ◽  
pp. 2065-2073 ◽  
Author(s):  
Simon Hanmer
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Finite Strain ◽  
Shear Zones ◽  
Simple Function ◽  
Strain Partitioning ◽  
Rock Types ◽  
The Matrix ◽  
Scale Shear

The classical macrotextural subdivision of quartzo-feldspathic mylonitic rocks yields only three rock types: protomylonite, mylonite, and ultramylonite. This restriction impedes detailed mapping of the internal textural transitions common in wide, deep-seated, crustal-scale shear zones, where such transitions may occur over kilometres and involve several clearly mappable textural types. The introduction of two objectively defined field mapping terms, "homoclastic" and "heteroclastic," describing the macroscopic grain-size distribution within the porphyroclast population provides descriptive flexibility without changing the matrix–porphyroclast basis of the established classification. This allows the description of textural paths other than protomylonite → mylonite → ultramylonite and facilitates the consideration of textural paths in terms of strain partitioning between the constituent grains of the deforming aggregate, rather than as a simple function of finite strain.

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