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Sodic Soils: Reclamation
Published in Brian D. Fath, Sven E. Jørgensen, Megan Cole, Managing Soils and Terrestrial Systems, 2020
Soluble sources of calcium ions are the most suitable sodic soil ameliorants. While gypsum is used most often, not all sources of gypsum are similarly effective or similarly suitable for each specific problem from sodicity. It was found[1,5] that only “by-product” gypsum, as a surface application, could prevent crusting. Mined gypsum was too slowly soluble for the purpose.[1] Gypsum is a by-product of many industrial processes.[5] Furthermore, gypsums from different mines can differ quite markedly in purity[6] They can also differ in dissolution rate. A finer particle size generally provides a greater solubility.[5] As well, sodium salts associated with gypsum (Table 1)[6] decrease its efficiency for amelioration.[7]
Ultrasonic Machining (USM)
Published in Gary F. Benedict, Nontraditional Manufacturing Processes, 2017
The results of the tests, as summarized in Table 6.1, indicated that the strengths of diamond-ground Si3N4 were significantly different depending upon the grinding direction. However the difference between machining directions were statistically insignificant for the specimens prepared by USM. A second finding indicated that with the USM specimens, a small difference in strength could be attributed to the abrasive particle size selected. The smaller particle size, and correspondingly finer surface finish, resulted in increased tensile strength.
Selective Agglomeration
Published in S. Komar Kawatra, Advanced Coal Preparation and Beyond, 2020
The most obvious effect of particle size distribution is that the liberation improves at finer particle sizes, allowing a cleaner product to be made. Finer particle size also results in increased surface area, which in turn requires more agglomerating liquid and therefore increases the reagent costs. Finer size distributions also result in stronger agglomerates which contain moisture overall, which requires balancing the required handling properties of the agglomerates against the maximum acceptable moisture content (Özer et al., 2017).
Effect of the Primary Air Ratio on Combustion of the Fuel Preheated in a Self-preheating Burner
Published in Combustion Science and Technology, 2022
Ziqu Ouyang, Hongliang Ding, Wen Liu, Xiaoyang Cao, Shujun Zhu
The coal char was collected at the outlet of the self-preheating burner and the particle size was analyzed, as shown in Figure 5. The hollow dotted line in Figure 5 was the size distribution of the raw fuel. Compared with the raw fuel, the coal char had more narrow particle size distribution range, which was mainly concentrated between 10 μm and 100 μm. It could be speculated that the large particles were burnt and broken in the self-preheating burner, while the smaller particles were consumed directly, which resulted in the highest proportion of medium particle size. It was seen that as increasing λp, the mean size of the coal char was smaller. Generally, the specific surface area was larger when the particle was finer, thus the reactivity was better. Therefore, increasing λp could improve the combustion performance of the coal char to some extent. But for very fine fuels, the effect of this method would not be obvious.
Treatment of produced water from Niger Delta oil fields using sequential mixture of bio-adsorbents
Published in Cogent Engineering, 2021
S.G Udeagbara, S.O Isehunwa, N.U Okereke, I. U Oguamah, A Kerunwa, O. Nwanwe
Figure 9 is also a plot of some of the metal concentrations against time. The metals are Pb, Ni, Cd, Cu, Cr, and Zn, with a particle size of 300 micron for the same sample X using same adsorbents arrangement on the plant as described above. The same nature of plot as in Figure 1.7 was obtained. It was a linear plot with negative slopes showing that there is a strong relationship between the dependent and the independent variable. The plot showed that the metal concentrations decrease as time increases. Unfortunately, with a particle size of 300 micron as can be seen on the result (Table 2), Pb and Cu could not be completely removed from the produced water sample unlike the particle size of 150 microns. It goes to show that particle size matters a lot when using the adsorbents. The finer the size of the particle, the more the surface area, and the better the result.
Spatial and temporal dynamics of sediment ecotoxicity in urban stormwater retention basins: Methodological approach and application to a pilot site close to Lyon in France
Published in Journal of Environmental Science and Health, Part A, 2018
Celine Becouze-Lareure, Gislain Lipeme Kouyi, Carolina Gonzalez-Merchan, Christine Bazin, Christel Sebastian, Sylvie Barraud, Yves Perrodin
The variation in pollutant concentration and in the resulting ecotoxicity of the sediments between the different sampling locations, potentially depends on the basin configuration and especially on its hydrodynamic behavior.[25,37,38] Our initial assumption was the link between different levels of ecotoxicity and the grain size of the particles (Table 2). The finer particles being generally more polluted,[39–42] we expected a higher ecotoxicity in the locations where fine particles predominated. We also knew from previous study that the most ecotoxic part in stormwater was the particulate and not the dissolved phase.[43] Except for P12 and to lesser extent P01 which were particular points, the grain size and the physico-chemical characteristics were rather homogeneous in space and the variation of ecotoxicity relatively low from one location to another. With the same level of metallic contamination, the ecotoxicity of the sediments in P12 was much higher than in the other points.