• Geomechanics and Engineering
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• v.28 no.6
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• pp.637-644
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• 2022

Loess soils are unsaturated and widely distributed in the northwest zone in China. Many steep slope of unsaturated are observed are observed to be naturally stable. However, a low factor of safety (FoS) for these slopes would be computed from the slope stability analysis following local code practices. It seems that the analyzed results following the local code practices do not agree with the real condition as observed in the field. It is commonly known that soil suction plays an important role in slope stability due to a higher shear strength of the unsaturated soil as compared with that of the saturated soil. In this paper, it is observed that the computed FoS can also be affected by unsaturated unit weight of the soil. However, the effect of unsaturated unit weight of the soil on the slope stability is commonly ignored in engineering practice. Therefore, both the effects of shear strength and unit weight of the unsaturated soil on the computed FoS of unsaturated soil slope are investigated in this study. It is observed that the unsaturated unit weight of soil on the computed FoS increases with increase in slope angle. It is also observed that the effects of the unsaturated shear strength and unsaturated unit weight on the computed FoS are more significant than the effect of 3D analyses compared to the 2D analyses on the FoS.

• Korean Journal of Poultry Science
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• v.32 no.1
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• pp.1-7
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• 2005

This study was carried out to estimate the effects of loess ($0\%$, $1.5\%$, $3\%$ and $5\%$) on the growth performance, meat quality, and blood composition of broiler chicks. A total of 320 broiler chicks at 1 day of age were divided into 4 groups to feed basal diet (control) and basal diet plus $1.5\%$ to $5.0\%$ loess respectively for 6 weeks. The body weight gain and feed conversion rate were not significantly different among the groups. The contents of moisture and crude fat of meats were significantly different in treatments when compared to that of the control group (P<0.05), but did not show any differences among the groups. The pH values of meats were not different among the treatments. However, water holding capacity was higher in all treated groups than the control. The L of meat color was also increased in all treated groups, but a and b of meat color were not different among the groups. In addition, the contents of unsaturated fatty acid content of meat were higher in the treated groups than the control. The concentrations of HDL cholesterol and triglyceride were significantly lower in all treated groups than the control (P<0.05). Finally, the contents of moisture of excreta were significantly lower in all treated groups than control (P<0.05). Taken together, it was concluded that loess did not improved the growth performance, but had effects on the improvement of meat quality.

• Journal of the Korean Society of Groundwater Environment
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• v.3 no.2
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• pp.70-79
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• 1996

The Friar Tuck Abandoned Coal Mine site is one of the most complexly disturbed areas in the midwestern United States. The deposits of gob and tailings contain high concentrations of pyrite, whose oxidation contributes to the acidification of soil and water and prevents the growth of vegetation. In an effort to quantitatively evaluate the effects of reclamation techniques, detailed monitoring program was performed. Water samples were collected from surface water, groundwater, and pore water from the unsaturated zone during a period of five years. According to the results, The spoil deposits are a relatively minor source of contamination and gob piles are the source of severe contamination to surface water and groundwater. But, loess and till beneath the gob piles effectively prevent the contaminated water migration from the source. Surface layers of the gob piles and the tailing deposits are less toxic than the interior of the deposits as a consequence of weathering over several decades. Acid mine drainage is in a post-peak stage and acid formation potential is probably situated in the unsaturated zone of refuse.