• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(2)
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• pp.233-240
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• 1996

Analyses of the viscous and end effects on electromagnetic (EM) pumps of annular linear induction type for the sodium coolant circulation in Liquid Metal Fast Breeder Reactors have been carried out based on the MHD laminar flow analysis and the electromagnetic field theory. A one-dimensional MHD analysis for the liquid metal flowing through an annular channel has been performed on the basis of a simplified model of equivalent current sheets instead of three-phase currents in the discrete primary windings. The calculations show that the developed pressure difference resulted from electromagnetic and viscous forces in the liquid metal is expressed in terms of the slip, and that the viscous loss effects are negligible compared with electromagnetic driving forces except in the low-slip region where the pumps operate with very high flow velocities comparable with the synchronous velocity of the electromagnetic fields, which is not applicable to the practical EM pumps. A two-dimensional electromagnetic field analysis based on an equivalent current sheet model has found the vector potentials in closed form by means of the Fourier transform method. The resultant magnetic fields and driving forces exerted on the liquid metal reveal that the end effects due to finiteness of the pump length are formidable. In addition, a two-dimensional numerical analysis for vector potentials has been performed by the SOR iterative method on a realistic EM pump model with discretely-distributed currents in the primary windings. The numerical computations for the distributions of magnetic fields and developed pressure differences along the pump axial length also show considerable end effects at both inlet and outlet ends, especially at high flow velocities. Calculations of each magnetic force contribution indicate that the end effects are originated from the magnetic force caused by the induced current ( u x B ) generated by the liquid metal movement across the magnetic field rather than the one (E) produced by externally applied magnetic fields by three-phase winding currents. It is concluded that since the influences of the end effects in addition to viscous losses are extensive particularly in high-velocity operations of the EM pumps, it is necessary to find ways to suppress them, such as proper selection of the pump parameters and compensation of the end effects.

• 청정기술
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• 제15권3호
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• pp.172-179
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• 2009

높은 강도, 경도, 신율, 비중 및 내마모성 등을 가진 채 폐기되는 열가소성 폴리우레탄 스크랩(TPU-S)과 습윤 상태의 내슬립성은 높으나 기계적 물성이 떨어지는 EPDM 고무의 용융 블렌드를 통해 신발 소재용 필름을 제조하고 조성과 특성과의 관계를 연구하였다. 블렌드 중의 TPU-S의 함량이 증가함에 따라 강도, 신도, 내마모성, 비중 및 경도 등 모든 물성이 증가하였으나, 습윤 상태의 내슬립성(동적마찰계수)은 크게 감소하였다. TPU-S 함량의 증가에 따라 블렌드의 파단신율은 단순혼합법칙 이상으로 증가하였으며, 습윤 상태의 내슬립성은 TPU-S가 $0{\sim}65%$ 범위에서 단순혼합법칙 이상이었다. 그러나 인장강도, 비중 및 내마모성은 모두 단순혼합법칙보다 낮은 값을 나타내었다. 이들 블렌드의 조성-특성 관계의 결과로부터 일반적으로 요구되는 신발 겉창용 소재의 물성에 충족되는 EPDM/TPU-S 블렌드의 조성은 무게비가 30/70인 것을 알 수 있었다.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제20권4호
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• pp.17-25
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• 2014

Purpose: Generally, rural housing in Korea have had target of people who are in good physical health rather than the disabled. Therefore, it is difficult to offer high quality residential environment for the elderly and the disabled. The purpose of this study is to propose the ways to promote ease and safety in the rural housing. Methods: This study evaluates the accidents, improvement factors, satisfactions, complaints by space of 153 rural housing in Taebaeksi. Results: This study divides the a rural house into 7 sectors : a passage to entrance, an entrance hall, a livingroom, a bedroom, a bathroom, a kitchen, and utility room. this study propose the following plan that rural housing to be barrier free space. First, in passage to entrance of the house, people with disabilities should not experience difficulties in walking, so installing ramps to remove the stepped slope grade without slip so that the floor finish should be. Second, entrance hall need more space to change and keep wheelchair. Third, switches and handle should be installed various height and form depend on the behavior of residents. Forth, install a drain to make no changes in level of bathroom. Implications: This research could be the basic data to renovate the rural housing.

• 한국의류산업학회지
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• 제20권2호
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• pp.219-225
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• 2018

The purpose of this study is to make an ideal dummy for adult Maltese with proper investigation of its character and direct measurement of dog body-shape. The results of the study are as follows; First, there were 6 factors to affect the characteristics of Maltese body in the analysis, which are size of body, leg shape, chest shape, leg thickness, body length, length between fore-legs. In the cluster analysis with the 6 factors there were two types of Maltese body. Type 1 has body characteristics with large body, thick leg, and small distance between front legs. Type 2 has average size of all factors including body size, leg thickness, and length between fore-legs. Second, type 2 was selected as a representative one to make a dummy reflected body shape of characteristics because it took 67.71% from entire considered factors and has average value in the measured size. The first dummy pattern was planned by copying the surface area of the representative body shape with the method of surgical tape. A dummy of single body with trunk and legs was made using 30's cotton cloth, polyester inside batting, compressed form PVC and metallic wire on the joint of trunk and legs to support dummy shape. The second pattern was made by correcting size difference of the pattern and adding the pattern of neck covering plate, metal magnetic button was inserted on the center of joint area of trunk and legs to make detachable legs for easy slip on and off the pet's wear.

• Steel and Composite Structures
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• 제27권3호
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• pp.389-399
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• 2018

A perforated shear connector group is commonly used to transfer shear in steel-concrete composite structures when the traditional shear stud connection is not strong enough. The multi-hole perforated shear connector demonstrates a more complicated behavior than the single connector. The internal force distribution in a specific multi-hole perforated shear connector group has not been thoroughly studied. This study focuses on the load-carrying capacity and shear force distribution of multi-hole perforated shear connectors in steel-concrete composite structures. ANSYS is used to develop a three-dimensional finite element model to simulate the behavior of multi-hole perforated connectors. Material and geometric nonlinearities are considered in the model to identify the failure modes, ultimate strength, and load-slip behavior of the connection. A three-layer model is introduced and a closed-form solution for the shear force distribution is developed to facilitate design calculations. The shear force distribution curve of the multi-hole shear connector is catenary, and the efficiency coefficient must be considered in different limit states.

• 한국구조물진단유지관리공학회 논문집
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• 제18권5호
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• pp.19-26
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• 2014

콘크리트 방호벽 및 중앙분리대는 교량의 부속시설이지만, 슬립폼 시공과 넓은 비표면적으로 인해 초기재령 균열이 발생하기 쉽다. 본 연구에서는 대형 교량의 방호벽과 중앙분리대 콘크리트의 외관조사 및 비파괴실험을 수행하여 균열의 원인과 발생 균열의 패턴을 분석하였다. 이를 위해 시공기간을 고려하여, 건조수축, 수화열 해석이 수행되었으며, 현장의 환경조건을 고려하여 소성수축 특성을 평가하였다. 평가결과 대상구조물의 균열 원인은 철근위치에 따른 소성침하균열, 소성수축 및 건조수축에 의한 복부균열, 재료분리에 따른 상부균열로 추정할 수 있었다. 또한 균열원인과 발생 패턴을 도식화하였으며, 시공 및 재료분야에서 균열제어대책을 제안하였다. 해상위 교량에 설치하는 중앙분리대 및 방호벽 콘크리트는 환경조건 (풍속, 온도, 습도)에 매우 민감하여 초기재령균열이 쉽게 발생하므로 재료선택 및 시공방법에 신중을 기해야 한다.

• 상하수도학회지
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• 제25권5호
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• pp.627-634
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• 2011

In the present study, the flow behaviors of square jets surface discharged and submerged discharged into shallow water were each simulated using computational fluid dynamics, and the results were compared. As for the verification of the models, the results of the hydraulic experiment conducted by Sankar, et al. (2009) were used. According to the results of the verification, the present application of computational fluid dynamics to the flow analysis of square jets discharged into shallow water was valid. As for the wall jet, which is one form of submerged discharges, at the bottom wall boundary, the peak velocity of the jet rapidly moved from the center of the jet to the bottom wall boundary due to the restriction of jet entrainment and the no-slip condition of the bottom wall boundary, and, as for the surface discharge, because jet entrainment is limited on the free water surface, the peak velocity of the jet moved from the center of the jet to the free water surface. This is because jet entrainment is restricted at the bottom wall boundary and the surface so that the momentum of the central core of the jet is preserved for considerable time at the bottom wall boundary and the surface. In addition, due to the effect of the bottom wall boundary and the free water surface, the jet discharged into shallow water had a smaller velocity diminution rate near the discharge outlet than did the free jet; at a location where it was so distant from the discharge outlet that the vertical profile of the velocity was nearly equal (b/x =20~30), moreover, it had a far smaller velocity diminution rate than did the free jet due to the effect of the finite depth.

• 한국한의학연구원논문집
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• 제15권2호
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• pp.85-91
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• 2009

The manufacture date of the number 198 wooden tablet excavated at Anapji is estimated to be between year 751 and 774. As medical artifacts around this period of time is scarce, the discovery of an artifact with distinct medical information such as names of medicinal drugs recorded in hand writing holds great value in the history of medicine. This wooden tablet was presumably a prescription for a medicinal formula. That the '灸' character which is a method of processing drugs is found after '甘草' indicates the possibility of this wooden tablet to be a practical form of prescription. On this slip, a certain sign can be found at the upper right corner of the names of drugs. This is thought to be an additional sign added to the original text. It seems to have been originated from the letter '了', based on the composition and finishing touches of the strokes, presumably to confirm the end of a work by adding the letter '了' which means 'to finish'. The base material of 靑黛 and 藍淀 are the same, and the two often took each other's place in a prescription. It is difficult to find an example of a formula where both drugs are included. Therefore, the prescription on the front with 靑黛, and the one on the back with 藍淀 of tablet 198 can be understood as separate formulas.

• 복식
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• 제65권5호
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• pp.51-61
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• 2015

This study examines the types and forms of underwear worn during the Joseon Dynasty period, and the purpose of this study is to apply the Joseon underwear design elements into designs of modern clothes, and make clothes that have practical use. In addition, it examines natural dyeing in the production of works, using a dye that contains tannin to increase color fastness. This study, first, looked into the types of female underwear during the late-Joseon Dynasty period through literature research and literature study. Second, the study chose artificial silk material (rayon), which was applied with dye containing tannin, and then with indigo (Jjok) and a different dye. Also, the study tested color fastness by washing the material, and rubbing fastness was tested if the material was either dyed with indigo. if it was dyed first with dye stuff containing tannin, and then with indigo dyeing color. Third, using the underwear types in the Joseon Dynasty period, the study developed and produced a dress, a skirt and pants that could be worn in modern life on a daily basis by applying Mujigi-chima (underwearskirt), Dan-sokgot (slip), Salchang-gojaengi (loosedrawers) and Sok-baji (bloomers) forms. Dresses applying underwear skirt using naturally-dyed artificial silk, dresses applying Salchang-gojaengi, dresses applying Dan-sokgot, skirt without a crotch designed in the form of pant swith an open crotch, and pant skirt with a crotch-applying pants with an open crotch were produced. In the future, hopefully, various studies of collaborations of Korean traditional clothing, and natural dyeing will continue to kee) the tradition alive.

• Structural Engineering and Mechanics
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• 제21권6호
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• pp.659-676
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• 2005

The novel form of composite walling system consists of two skins of profiled steel sheeting with an in-fill of concrete. The behaviour of such walling under in-plane shear is important in order to utilise this system as shear elements in a steel framed building. Steel sheet-concrete interface governs composite action, overall behaviour and failure modes of such walls. This paper describes the finite element (FE) modelling of the shear behaviour of walls with particular emphasis on the simulation of steel-concrete interface. The modelling of complex non-linear steel-concrete interaction in composite walls is conducted by using different FE models. Four FE models are developed and characterized by their approaches to simulate steel-concrete interface behaviour allowing either full or partial composite action. Non-linear interface or joint elements are introduced between steel and concrete to simulate partial composite action that allows steel-concrete in-plane slip or out of plane separation. The properties of such interface/joint elements are optimised through extensive parametric FE analysis using experimental results to achieve reliable and accurate simulation of actual steel-concrete interaction in a wall. The performance of developed FE models is validated through small-scale model tests. FE models are found to simulate strength, stiffness and strain characteristics reasonably well. The performance of a model with joint elements connecting steel and concrete layers is found better than full composite (without interface or joint elements) and other models with interface elements. The proposed FE model can be used to simulate the shear behaviour of composite walls in practical situation.