• International Journal of Highway Engineering
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• v.15 no.5
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• pp.31-45
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• 2013

PURPOSES : Determination of particle packing model variables that can be used for formulation of new DEM based particle packing model by examining existing particle packing models METHODS : Existing particle packing models are thoroughly examined by analytical reformulation and sensitivity analysis in order to set up DEM based new particle packing model and to determine its variables. All model equations considered in this examination are represented with consistent expressions and are compared to each others to find mathematical and conceptual similarity in expressions. RESULTS : From the examination of existing models, it is observed that the models are very similar in their shapes although the derivation of the models may be different. As well, it is observed that variables used in some existing models are comprehensive enough to estimate particle packing but not applicable to DEM simulation. CONCLUSIONS : A set of variables that can be used in DEM based particle packing model is determined.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.4
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• pp.554-560
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• 2001

Hydrophilic treatment of the packing materials in a cooling tower has been made by the ion assisted reaction (IAR) method to increase the wettability of the packing materials. The effects of hydrophilic treatment of packing materials on the performance of a cooling tower have been investigated in a wide range of operating parameters, such as water flow rate, air flow rate, and the water inlet temperature. A pilot cooling tower has been designed and built to model a counter-flow cooling tower. The results obtained indicate that the packing characteristic value with hydrophilic packing could be substantially increased by 6∼19.3% than that with conventional packing in the operating ranges considered. The correlations of the packing characteristic value as a function of water-to-air ratio are suggested for a counter-flow cooling tower with hydrophilic packing as well as with conventional packing.

• Fashion & Textile Research Journal
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• v.9 no.4
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• pp.445-449
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• 2007

The results of warmth retaining, heat transfer and compressive elastic recovery of the five kinds of bedspread fabrics, which were produced from packing weft of 2700 denier and 3600 denier batt yarn treated with raw material of Polyester $150^D$/48 DTY, are as follows: 1) 3600 denier packing weft showed lover count in compressive elastic recovery than 2700d packing weft, so it took longer time to recover. 2) When packing weft of the same count is used, a sample of packing weft with higher density showed lower recovery. 3) It took 2700d packing weft 30min to get approximately 98% recovery in temperature $30^{\circ}C$. But, 3600d packing weft stayed under 98% recovery in the same temperature. Considering only the result of compressive elastic recovery, we should use 2700d packing weft. 4) The higher the density of packing weft is, the higher warmth retaining becomes. Although sharp increase appeared until 5min, equilibrium was kept without any increase after that time. 5) When 2700d packing weft was used, the maximum warmth retaining was approximately 60% and 64% in the conditions of density 12(thread/in) and 22(thread/in) respectively.

• Journal of Korea Foundry Society
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• v.22 no.3
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• pp.137-143
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• 2002

Silica sand, zircon sand, and steel shots were used as mold packing materials in lost foam casting of the aluminum alloy bar. Vibration acceleration in three directions and temperatures in the casting and mold were measured, and packing and cooling characteristics of these materials were investigated. Packing densities increased with increase in vibration magnitude and time, and were $1.41{\sim}1.49g/cm^2$ for silica sand, $2.54{\sim}2.86g/cm^2$ for zircon sand, and $3.92{\sim}4.52g/cm^2$ for steel shots. Sound castings were obtained only without evacuation of the flask during pouring. Solidification time became faster in order of silica sand, zircon sand and steel shot packing because steel shot has the highest cooling capacity of them. Solidification time of steel shot packing was shortened to about 1/2 of silica sand packing. Cooling capacity of sand mold was generally evaluated by heat diffusivity of the mold, however could be simply evaluated with specific heat per unit volume of the packing material in lost foam casting.

• Nuclear Engineering and Technology
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• v.53 no.8
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• pp.2509-2522
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• 2021

A valve assembly used in nuclear power plants must be qualified and supervised. New technical standards such as ASME QME-1 2007 particularly require detailed qualification using experiment and analysis. Particularly, diagnostic tests and engineering studies are required for qualification of ASME QME-1 2007. Among these studies, the research on the measurement of friction coefficient and packing stress is important. The irregular change of packing stress along the stroke distance occurs because of the abnormal phenomenon, which must be found and studied with quantitative methods. Packing stress should be analyzed conservatively through experimentation and analysis. In this study, various formulas were applied to measure and calculate coefficient of friction and packing stress. This study can be used in relation to qualification and supervision of packing materials. And the calculation using static diagnosis test can be used to find the packing frictional force in dynamic diagnosis test with flow pressure in a pipe. This study has made it possible to reliably consider packing frictional force generated in a valve body. And so, it is believed that more margin can be secured when evaluating the capacity of valve actuator by applying the accurate frictional force generated in the valve assembly.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.715-720
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• 2001

The main reason for applying positive pressure variable clearance packing in fossil power plant is high efficiency and energy saving movement in the government. This study intends to analyze the turbine efficiency through the shaft packing improvement in thermal power plant and makes its comparison to that of the used packing.

• Communications of the Korean Mathematical Society
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• v.22 no.2
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• pp.241-246
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• 2007

We investigate the relation between Hausdorff(packing) measure and lower(packing) Cantor measure on a deranged Cantor set. If the infimum of some distortion of contraction ratios is positive, then Hausdorff(packing) measure and lower(packing) Cantor measure of a deranged Cantor set are equivalent except for some singular behavior for packing measure case. It is a generalization of already known result on the perturbed Cantor set.

• Kyungpook Mathematical Journal
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• v.56 no.3
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• pp.745-754
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• 2016

In a graph G = (V, E), a non-empty set $S{\subseteq}V$ is said to be an open packing set if no two vertices of S have a common neighbour in G. The maximum cardinality of an open packing set is called the open packing number and is denoted by ${\rho}^{\circ}$. In this paper, we examine the effect of ${\rho}^{\circ}$ when G is modified by deleting a vertex.

• Journal of Korean Society of Rural Planning
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• v.5 no.2 s.10
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• pp.1-13
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• 1999

Packing house is the regional center in which packing, sorting, storage, and selling of harvested fruits are taken care of all together. It is located at the producing centers, and commercializes their apples. Apple grading policies of chief producing centers should concentrate on enhancing functions and roles of its local packing house. Consequently new packing house policies for enacting individual grading standards at national and local levels should be developed. This study is to develop Korea packing house on the basis of field survey in New York State. Increasing the utilization of packing house is the main key to the success of apple grading project. Therefore, effective arrangement and utilization of sorting facilities should be evaluated and new system which enables apple farms, local cooperatives, and corporations to joint-utilize packing house must to be established.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.17-20
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• 2000

가전업의 CKD(Complete Knock Down)업무는 해외의 바이어나 현지공장에 가전제품을 구성하는 부품/반제품들을 개별 포장하여 수출하는 물류업무이다. 이러한 CKD 업무는 가격경쟁이 치열한 부분으로 경쟁력 강화를 위해 물류비의 절감이 요구되고 있다. 특히 CKD 업무의 경쟁력 강화를 위해서는 포장품질과 적재율 향상을 위한 포장/적재의 최적화가 이루어져야 하며, 이를 지원하는 Packing Optimization System 의 구축이 절실히 필요하다. 본 논문에서는 가전업 CKD의 업무특징과 업무환경의 변화에 대해 기술하였으며, 환경변화에 대한 대응방법으로 가전업 CKD 업무를 위한 Packing Optimization System 의 주요 기능과 업무 프로세스를 제시하였다. 그리고, 시뮬레이션 방법을 이용한 Packing Optimization system의 구현 사례를 예시하였다.