Flow Characteristics and Grain Size Distribution of Granular Gangue Mineral by Compaction Treatment

A test system for water flow in granular gangue mineral was designed to study the flow characteristics by compaction treatment. With the increase of the compaction displacement, the porosity decreases and void in granular gangue becomes less. The main reason causing initial porosity decrease is that the void of larger size is filled with small particles. Permeability tends to decrease and non-Darcy flow factor increases under the compaction treatment. The change trend of flow characteristics shows twists and turns, which indicate that flow characteristics of granular gangue mineral are related to compaction level, grain size distribution, crushing, and fracture structure. During compaction, larger particles are crushed, which in turn causes the weight of smaller particles to increase, and water flow induces fine particles to migrate (weight loss); meanwhile, a sample with more weight of size (0–2.5 mm) has a higher amount of weight loss. Water seepage will cause the decrease of some chemical components, where SiO2 decreased the highest in these components; the components decreased are more likely locked at fragments rather than the defect of the minerals. The variation of the chemical components has an opposite trend when compared with permeability.

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Uniformity of Grain Coarsening in Submicron Grained Al-Sc Alloy Containing Local Variations in Texture

Materials Science Forum ◽

10.4028/www.scientific.net/msf.495-497.609 ◽

2005 ◽

Vol 495-497 ◽

pp. 609-614

Author(s):

Michael Ferry

Keyword(s):

Grain Size ◽

Size Distribution ◽

Grain Size Distribution ◽

Fine Particles ◽

Volume Fraction ◽

Marked Change ◽

Grain Coarsening ◽

Large Volume Fraction ◽

Orientation Gradient ◽

Distribution Boundary

The effect of fine particles on the uniformity of grain coarsening in a submicron grained Al-Sc alloy containing significant local variations in texture has been investigated using high resolution EBSD. The alloy was processed by severe plastic deformation and low temperature ageing to generate a fine-grained (0.8 µm diameter) microstructure containing either a dispersion of nanosized Al3Sc particles or a particle-free matrix. The initial processing generated a uniform grain size distribution, but the distribution of grain orientations was inhomogeneous with the microstructure containing colonies of grains consisting predominantly of either HAGBs or LAGBs with the latter possessing orientation gradients of up to 10 o/µm. Despite the marked differences in boundary character between these regions, the alloy undergoes slow and uniform grain coarsening during annealing at temperatures up to 500 oC with no marked change in the grain size distribution, boundary distribution and texture. A model of grain coarsening that takes into account the influence of fine particles on the kinetics of grain growth within an orientation gradient is outlined. The model predicts that a large volume fraction of fine particles (large f/r-value) tends to homogenize the overall rate of grain coarsening despite the presence of orientation gradients in the microstructure.

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The grain size distribution of settled sediment within storage reservoir Otmuchów

Annals of Warsaw University of Life Sciences – SGGW Land Reclamation ◽

10.1515/sggw-2017-0001 ◽

2017 ◽

Vol 49 (1) ◽

pp. 3-14

Author(s):

Robert Głowski ◽

Robert Kasperek

Keyword(s):

Grain Size ◽

Size Distribution ◽

Grain Size Distribution ◽

Fine Particles ◽

Satellite Image ◽

Walking Distance ◽

Sediment Grain Size ◽

Storage Reservoir ◽

Storage Reservoirs ◽

Reservoir Length

Abstract The grain size distribution of settled sediment within storage reservoir Otmuchów. The river Nysa Kłodzka is flowing through the flat-reduction Otmuchów. There are localized two storage reservoirs Otmuchów and Nysa. The first of these reservoirs have been constructed in the period 1928-1933 and the filling was completed in 1934. Reservoir Nysa was completed in 1971. Both reservoirs are located within walking distance of each other, creating since 1971 cascade. Reservoir Otmuchów is located above the Nysa reservoir what cause, that in the bowl of the Otmuchów reservoir, the significant part of transported by Nysa Kłodzka sediments is deposited. When established after the 1997 flood damming levels, summer and winter, the length of the reservoir Otmuchów is suitably from 4.5 to 5 km. At the maximum impoundment level and a maximal capacity of 130.45 million m3 the reservoir length reach approx. 7 km. From the analysis of the satellite image can be seen advancing silting of the reservoir Otmuchów especially in the estuary zone of the Nysa Kłodzka. Obtained archival data about changes of the sediment grain size distribution in the longitudinal reservoir profile cover only the region of the still capacity extending a distance of 3 km from the cross-section of the dam. In this zone the fine particles of the suspended load with characteristic diameters ranging from 0.030 to 0.088 mm were embedded. In 2010, the authors presented the results of preliminary analysis of the silting process of the reservoir Otmuchów. The authors pointed out that there is a lack of the data about the dimension of the particles embedded in the usable capacity and flood capacity reserve (above 3 km from the dam) causing visible on satellite photo silting. This paper presents the results of the sediment grain size distribution in the usable capacity of the reservoir and in the estuary region of the Nysa Kłodzka located in flood capacity reserve, obtained from the sediment samples analysis. Obtained results allowed to supplement the image of the particle size distribution of the sediment being deposited in the reservoir Otmuchów longitudinal profile and an evaluation of the parameters of mobility rubble with fixed diameters.

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The effect of debris-flow sediment grain size distribution on fan forming processes

10.5194/esurf-2021-69 ◽

2021 ◽

Author(s):

Haruka Tsunetaka ◽

Norifumi Hotta ◽

Yuichi Sakai ◽

Thad Wasklewicz

Keyword(s):

Grain Size ◽

Debris Flow ◽

Size Distribution ◽

Grain Size Distribution ◽

Flow Characteristics ◽

Granular Flows ◽

Spatial Diversity ◽

Flume Experiments ◽

Sediment Grain Size ◽

Average Grain Size

Abstract. Knowledge of the processes driving debris-flow fan evolution are critical in the support of efforts to mitigate related hazards, reduce risk to populations and infrastructure, and reconstruct the history of sediment dynamics in mountainous areas. Research on debris-flow fan development has focused on topographic controls, debris-flow volume and rheology, and the sequence of occurrence of debris flows. While these items have explained a great deal about fan formation and specifically avulsion and runout mechanisms, there is a need to further investigate other properties as they relate to debris-flow fan formative process. Here, we examined the role of debris-flow grain-size distribution on fan formation. Flume experiments were employed to examine the morphology of debris-flow fans that resulted from flows with mono- or multi-granular sediment composition with the same average grain size. All other flow characteristics were held constant. The mono-granular flows formed a symmetric-like fan morphology because there was little avulsion during the formation process. The multi-granular flows produced fans with an asymmetric morphology. Avulsions occurred on both lateral extents of the fan during the early stages of fan development and caused the runout direction to shift produce the fan asymmetry. Grain-size distribution was closely related to spatial diversity in fan morphology and stratigraphy.

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Blast Furnace Slag Foundation Packing Grading and Compaction Characteristics Analysis

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.368-370.855 ◽

2013 ◽

Vol 368-370 ◽

pp. 855-859

Author(s):

Xiang Liu ◽

Rui Jie Yu

Keyword(s):

Grain Size ◽

Size Distribution ◽

Grain Size Distribution ◽

Fine Particles ◽

Filler Particle ◽

Dry Density ◽

Maximum Dry Density ◽

Filler Particle Size ◽

Characteristics Analysis ◽

Different Depths

Through the packing particles analysis test and heavy compaction test at different depths of new system of Baotou steel finished product of the test section , analysis of the grain size distribution of slag and fly ash mixture and the content of coarse and fine particles on compaction effect are conducted , the results show that the filler embankment foundation is mainly for uniform gradation and continuous filler, when the coarse particle of the filler is 83% ～ 84% content, the compaction effect is best. Using multiple linear regression, the grain size distribution characteristics of the filler particle size equation, coarse and fine particle content and maximum dry density of the regression equation are obtained .

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