http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Numerical Particle-Scale Study of Swelling Pressure in Clays
David W. Smith,Guillermo A. Narsilio,Peter Pivonka 대한토목학회 2009 KSCE Journal of Civil Engineering Vol.13 No.4
The particle level responses to different external loadings of a montmorillonitic clay soil are investigated numerically. The soil is saturated by a solution of monovalent counterions, of varying concentrations. We use finite element micromechanical models (based on the Poisson-Nernst-Planck equations) to estimate counterion and electrical potential distributions around individual clay particles at various distances from one another, since analytical solutions are not possible for these complex arrangements of particles. Disjoining pressures are then estimated using the Van’t Hoff relation and Maxwell stress tensor. As the distance between the clay particles decreases and double-layers overlap, the concentration of counterions in the micropores between clay particles increases. This increase lowers the chemical potential of the pore fluid and creates a chemical potential gradient in the solvent that generates the so-called “disjoining” or “osmotic” pressure. Because of this disjoining pressure, it is clear that particles need not contact one another in order to carry an “effective stress”. This work may lead towards theoretical predictions of the macroscopic load deformation response of montmorillonitic soils based on micro-electro-chemo-mechanical modelling of particles. The particle level responses to different external loadings of a montmorillonitic clay soil are investigated numerically. The soil is saturated by a solution of monovalent counterions, of varying concentrations. We use finite element micromechanical models (based on the Poisson-Nernst-Planck equations) to estimate counterion and electrical potential distributions around individual clay particles at various distances from one another, since analytical solutions are not possible for these complex arrangements of particles. Disjoining pressures are then estimated using the Van’t Hoff relation and Maxwell stress tensor. As the distance between the clay particles decreases and double-layers overlap, the concentration of counterions in the micropores between clay particles increases. This increase lowers the chemical potential of the pore fluid and creates a chemical potential gradient in the solvent that generates the so-called “disjoining” or “osmotic” pressure. Because of this disjoining pressure, it is clear that particles need not contact one another in order to carry an “effective stress”. This work may lead towards theoretical predictions of the macroscopic load deformation response of montmorillonitic soils based on micro-electro-chemo-mechanical modelling of particles.
The Sawfly Genus Periclista in Korea and Taiwan (Hymenoptera: Tenthredinidae)
Smith, David R. 한국곤충학회 1984 Korean journal of entomology Vol.14 No.1
Six new species of Perictista from East Asia are described, Periclista satoi, P. suweonensis, P. serratae, and P. patura from Korea, and P. taiwanensis and P. shinoharai from Taiwan. These are the first records of Periclista from Korea and Taiwan. These species are known to feed on Quercus spp., P. satoi, P. suweonensis, and P. serratae.
GOING SOUTH : GLOBAL RESTRUCTURING AND GARMENT PRODUCTION IN THREE EAST ASIAN CASES
Smith, David A. the Institute for Far Eastern Studies, Kyungnam Un 1996 ASIAN PERSPECTIVE Vol.20 No.2
The textile and garment industries are extremely interesting cases of global economic restructuring. This paper illustrates the factors promoting the shift of apparel production-and other light industries-away from core and semiperipheral regions in the world-economy, illuminates some of the complexities and nuances of that process, and discusses the implications of this for the regional division of labor in East Asia. The story begins in South Korea, where apparel manufacturing, which grew rapidly during the 1970s and 1980s, faces an uncertain future in the 1990s, due to escalating wages and severe labor shortages. This forces Korean garment makers to seek "offshore" production sites. Southeast Asia, along with Central America and the Caribbean, became attractive targets for Korean apparel investment. In the 1980s, Indonesia, with its cheap and abundant labor and a state eager to welcome foreign investment, was a powerful magnet for garment capital from Korean and the other Asian NICs. Despite some recent wage pressure and labor unrest, this country-along with China-seems well-positioned to continue as a major global "sourcing" area. More recently, Vietnam, with a nominally Communist regime pushing a policy of "market liberalization" and gradually improving relations with its old enemy the United States, appears poised to become a big palyers in world apparel production. Garment manufactures from South Korea and elsewhere have begun to set up factories in Vietnam to take advantage of the country's large, industrious, and extremely cheap labor force. Dealing with a rapidly changing global apparel production and marketing system presents special challenges to the states, local capital, and workers throughout this region.