scholarly journals Geochemical Partitioning of Heavy Metals in Roadside Surface Soils of Different Grain Size along Major Roads in Kano Metropolis, Nigeria

2011 ◽  
Vol 1 (3) ◽  
pp. 94-115 ◽  
Author(s):  
O. Okunola
Keyword(s):  
Heavy Metals ◽  
Grain Size ◽  
Surface Soils ◽  
Geochemical Partitioning ◽  
Different Grain Size

Critical passivation mechanisms on heavy metals during aerobic composting with different grain-size zeolite

2020 ◽  
pp. 124313
Author(s):  
Hu Cui ◽  
Yang Ou ◽  
Lixia Wang ◽  
Baixing Yan ◽  
Yingxin Li ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Grain Size ◽  
Aerobic Composting ◽  
Different Grain Size

Study on the Behavior of the Cast-Iron Bonded Grinding Wheel to Machining Properties of Hard and Brittle Materials

2007 ◽  
Vol 24-25 ◽  
pp. 229-232
Author(s):  
S.L. Ma ◽  
Wei Li ◽  
Cong Rong Zhu ◽  
J. Zhang ◽  
H.C. Ye
Keyword(s):  
Grain Size ◽  
Cast Iron ◽  
Tungsten Carbide ◽  
Surface Quality ◽  
Ground Surface ◽  
Grinding Wheel ◽  
Different Grain Size ◽  
Grinding Efficiency ◽  
Machining Properties

Tungsten carbide which is a hard and brittle material was ground by cast-iron bonded diamond wheel with ELID (Electrolytic In-Process Dressing) technique, for the purpose of getting high efficiency, super-precision machining. Three kinds of cast-iron bonded diamond wheels with different grain size were adopted to get different grinding efficiency and surface quality of workpieces. The grinding properties of cast-iron bonded grinding wheels with different grain size and the ground surface quality of tungsten carbide are discussed in this paper. The experiment results indicate that, under the same feeding amount, the grinding efficiency of the wheel with bigger grain size is higher, and it could make the dimension accuracy of the workpiece controllable, but the wheel with smaller grain size could get better ground surface quality. The two grinding phases are decided by the ratio between the size of abrasive grain and the thickness of the oxide layer on the grinding wheel.

The distribution of lead, zinc, and chromium in fractions of bottom sediments in the Narew River and its tributaries

2008 ◽  
Vol 37 (4) ◽  
Author(s):  
Mirosław Skorbiłowicz ◽  
Elżbieta Skorbiłowicz
Keyword(s):  
Heavy Metals ◽  
Grain Size ◽  
Bottom Sediment ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Bottom Sediments ◽  
Catchment Area ◽  
Sediment Pollution ◽  
Lead Zinc

The distribution of lead, zinc, and chromium in fractions of bottom sediments in the Narew River and its tributariesThe purpose of the paper was to evaluate the distribution of lead, zinc and chromium contents in different grain fractions of bottom sediments in the Narew River and some of its tributaries. This study also aimed to determine which fractions are mostly responsible for bottom sediment pollution. The studies of the Narew and its tributaries (the Supraśl, Narewka, and Orlanka) were conducted in September 2005 in the upper Narew catchment area. The analyzed bottom sediments differed regarding grain size distribution. The studies revealed the influence of the percentage of particular grain fractions present on the accumulation of heavy metals in all bottom sediments.

scholarly journals Improvement ratio and behavior of bearing capacity factors for strip skirt footing model resting on sand of different grain size distribution

2018 ◽  
Vol 162 ◽  
pp. 01026
Author(s):  
Mahmood Rashid Mahmood
Keyword(s):  
Grain Size ◽  
Bearing Capacity ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Coarse Sand ◽  
Linear Increase ◽  
Angle Of Internal Friction ◽  
Theoretical Approaches ◽  
Different Grain Size ◽  
Improvement Ratio

Plain strain model tests were performed on beds of sands with different particle size distribution (Coarse, Medium and Fine) prepared at loose state (Relative density Dr. of 30%). A strip footing model with skirt was placed on the bed of sand and loaded vertically up to failure at different ratios of skirt depth to width D/B of (0.5, 1.0, 1.5, 2, and 3). The applied stress increments and the corresponding settlements were measured. The improvement ratio due to different skirt depth and the behavior of bearing capacity parameters Nγ and Nq at each depth were evaluated and compared with some theoretical approaches. The test results revealed that the improvement ratio increased linearly up to D/B of 1.5 then reduced. Two factors were introduce into the general bearing capacity equation where used to evaluate bearing capacity of skirt footing, there values are about 1.6 for skirt ratio ranged between 0.5 to 1.5, and 1.25 for skirt ratio more than 1.5. Also, it is found that the Nγ parameter for D/B=0 were very close to Vesic proposal for fine and medium grain size distribution, while it’s close to Biarez proposal for coarse sand. The behavior of Nq parameter with different skirt ratio shows slight increase up to D/B of 1.5 then decrease with increasing D/B ratio for different grain size distribution. While the behavior of theoretical Nq parameter (depending on angle of internal friction values) shows a linear increase with skirt ratio for different grain size distribution.

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