• 한국산학기술학회논문지
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• 제7권4호
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• pp.671-678
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• 2006

진동해머를 이용한 널말뚝 시공은 소음에 민감한 도심지 굴착 공사에 유용하다. 그러나 널말뚝의 진동-항타 시공시 항타관입성에 대한 연구는 거의 수행된 적이 없다. 이 연구에서는 국내에서 많이 사용되고 있는 U형 널말뚝을 진동해머를 이용하여 시공할 때 여러 가지 조건에 따른 항타관입성을 WEAP 프로그램을 이용하여 분석하였다. 해석결과 널말뚝의 관입속도는 N값이 클수록 느려지며, 20m 이내로 시공되는 경우 단면적이 클수록 느려지는 것으로 나타났다.

• Journal of the Korean Wood Science and Technology
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• 제44권2호
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• pp.283-293
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• 2016

Owing to an increase in the air tightness of recent buildings, the natural ventilation rate was significantly lowered and the removal of accumulated moisture became difficult in these buildings. The hygrothermal performance of these buildings should be carefully considered to provide comfortable indoor environment by removing the moisture condensation risk and the mold growth potential. In this study, hygrothermal performance of two selected wall structures was investigated based on WUFI simulation program. The results displayed that the indoor temperature had impact on the moisture accumulation in the insulation layer for both modeled walls, showing that lower indoor temperature resulted in higher moisture accumulation, especially in the wood frame structure. Also, the yearly moisture accumulation profile exhibited a downward shift throughout the year by adding a vapour retarder with a lower sd-value. In addition, both of the two walls have condensation risk in winter, due to low temperature level. The wood frame structure has a bigger fluctuation and higher condensation risk than the concrete structure.

• Wind and Structures
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• 제23권4호
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• pp.301-311
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• 2016

The numerous benefits of Savonius turbine such as simple in structure, has appropriate self-start ability, relatively low operating velocity, water acceptance from any direction and low environmental impact have generated interests among researchers. However, it suffers from a lower efficiency compared to other types of water turbine. To improve its performance, parameters such flow pattern, pressure and velocity in different conditions must be analyzed. For this purpose, a detailed description on the flow field of various types of Savonius rotors is required. This article presents a numerical study on a nonlinear two-dimensional flow over a classic Savonius type rotor and a Benesh type rotor. In this experiment, sliding mesh was used for solving the motion of the bucket. The unsteady Reynolds averaged Navier-Stokes equations were solved for velocity and pressure coupling by using the SIMPLE (Semi-Implicit Method for Pressure linked Equations) algorithm. Other than that, the turbulence model using $k-{\varepsilon}$ standard obtained good results. This simulation demonstrated the method of the flow field characteristics, the behavior of velocity vectors and pressure distribution contours in and around the areas of the bucket.

• 대한간호학회지
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• 제31권5호
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• pp.858-870
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• 2001

Purpose: This study was to compare changes in health behaviors, motivational factors, cardiovascular risk factors, and functional status (SIP) after implementing the 6-month motivation-enhancing program to institutionalized elderly women. Methods: Sixty-four elderly women participated. Face to face interviews with blood sampling and anthropometric assessment were conducted at the pretest, 10 weeks and 6 months during the program. Results: 1. The program participants showed significantly better health behaviors over 6 months. The mean motivational level was also significantly improved, especially for perceived benefits, perceived barriers, and emotional salience. 2. The mean of cardiovascular risk factors for the participants was 21.8 at the level of low to moderate risk. After completing the program, total risk score was significantly decreased to 18.7 at 10 weeks, and further to 17.7 at 6 months. A significant reduction was also found in HDL and LDL-cholesterol levels, blood pressure, obesity, inactivity, and stress. 3. The functional status (SIP) was 11% at the baseline and significantly changed in positive direction at 10 weeks(M=9.3) and at 6 month(M=6.3). The significant improvement was also found in physical and psychosocial dimensions and sleep/rest dimension. Conclusion: The motivation enhancing program was effective to reduce cardiovascular risks and to improve the functional status of institutionalized elderly women by motivating them to perform better health behaviors.

• 한국환경과학회지
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• 제19권2호
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• pp.137-148
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• 2010

This paper investigates the characteristics of turbulence schemes. Turbulence closures are fundamental for modeling the atmospheric diffusion, transport and dispersion in the boundary layer. In particular, in non-homogeneous conditions, a proper description of turbulent transport in planetary boundary layer is fundamental aspect. This study is based on the Regional Atmospheric Modeling System (RAMS) and combines four different turbulence schemes to assess if the different schemes have a impact on simulation results of vertical profiles. Two of these schemes are Isotropc Deformation scheme (I.Def) and Anisotropic deformation scheme (A.Def) that are simple local scheme based on Smagorinsky scheme. The other two are Mellor-Yamada scheme (MY2.5) and Deardorff TKE scheme (D.TKE) that are more complex non-local schemes that include a prognostic equation for turbulence kinetic energy. The simulated potential temperature, wind speed and mixing ratio are compared against radiosonde observations from the study region. MY2.5 shows consistently reasonable vertical profile and closet to observation. D.TKE shows good results under relatively strong synoptic condition especially, mixing ratio simulation. Validation results show that all schemes consistently underestimated wind speed and mixing ratio but, potential temperature was somewhat overestimated.

• BMB Reports
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• 제47권1호
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• pp.15-20
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• 2014

Intracellular lipid-binding proteins (LBPs) impact fatty acid homeostasis in various ways, including fatty acid transport into mitochondria. However, the physiological consequences caused by mutations in genes encoding LBPs remain largely uncharacterized. Here, we explore the metabolic consequences of lbp-5 gene deficiency in terms of energy homeostasis in Caenorhabditis elegans. In addition to increased fat storage, which has previously been reported, deletion of lbp-5 attenuated mitochondrial membrane potential and increased reactive oxygen species levels. Biochemical measurement coupled to proteomic analysis of the lbp-5(tm1618) mutant revealed highly increased rates of glycolysis in this mutant. These differential expression profile data support a novel metabolic adaptation of C. elegans, in which glycolysis is activated to compensate for the energy shortage due to the insufficient mitochondrial ${\beta}$-oxidation of fatty acids in lbp-5 mutant worms. This report marks the first demonstration of a unique metabolic adaptation that is a consequence of LBP-5 deficiency in C. elegans.

• Journal of Advanced Marine Engineering and Technology
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• 제40권8호
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• pp.686-691
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• 2016

This paper employs numerical tools to obtain an optimal thermal design of a heat exchanger with plain-fins. This heat exchanger is located at the condensing section of a crevice-type heat pipe. The plain-fins in the heat exchanger are radically mounted to two tubes in the condensing section. To obtain the optimal design parameters, a computational fluid dynamics technique is introduced and applied to different placement configurations in a system module. Owing to its effects on the heat pipe performance, the temperature difference between the tube surfaces and ambient air is investigated in detail. A greater heat dissipation rate occurs when the plain-fin offsets change from 2 to 3 mm. When this temperature difference is ${\Delta}T=70^{\circ}C$, the upper part of the plain-fins undergoes an accumulation of heat. At below $70^{\circ}C$, the dissipation of heat is accepted. A rectangular plain-fin geometry with varying widths and heights does not have a significant impact on the heat dissipation through-out the overall system. In addition, the temperature distributions between different plain-fin pitches show an equal profile even with different fin pitches.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2001년도 제16회 학술발표회 논문초록집
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• pp.91-94
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• 2001

A structural test of the wind turbine rotor blade must be required to evaluate the uncertainty in design assessment due to use of material, design concepts, production processes and so on, and the possible impact on the structural integrity. In the full-scale static strength test, the measuring parameters are strain, displacements, loads, weight and the center of gravity. There are test equipments, measuring sensors, a test rig and fixtures to obtain measuring parameters. In order to simulate the aerodynamics load, the three-point loading method instead of the one-point loading method is applied. There is slightly some difference between the measured results and the predicted results with the reference fiber volume fraction of 60%. However, the agreement between the measured results and the predicted results with the actual fiber volume fraction of 52.5% is good. Even though a slightly non-linearity from 80% loading to 100% loading, a linear static solution is sufficient for the design purpose as the amount of the non-linearity is relatively small. Comparison between measured and predicted strain results at the maximum thickness positions of the blade profile for 0.236R(5.56m), 0.493R(11.59m) and 0.574R(13.43m), under 20%, 40%, 60%, 80% and 100% loadings for the upper part of the blade. The predicted values are in good agreement with the measured values.

• 대한안전경영과학회지
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• 제16권3호
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• pp.219-229
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• 2014

Employees used computer significantly(IT employee) is increased by technological development in workplace. This study tried to find the magnitude of IT employees and the profile of their working conditions and ill health experiences in South Korea. Korean Working Conditions Survey was used with descriptive and mean difference test in order to find the difference working conditions and ill health status among the groups classified by the degree of using computer during work. Some of working conditions was positively correlated with the density of computer use such as work autonomy, the exposure of repetitive movement of hand and arms. The pain of upper extreme was also more frequently found in the highest user group of computer than lower user groups. Based on the result of hierarchical regression analysis, the effect of computer using on the experience of work-related symptoms after controlling other factors was shown as U shape. This study as heuristic one suggest that some of depth analysis with hypothesis will be done to identify the causes and pathway of impact of computer use.

• 한국환경과학회지
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• 제25권9호
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• pp.1223-1231
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• 2016

To create urban landscapes that take human emotion into consideration, the present study verified the psychological effects of artificial waterscape facilities on users, as these facilities significantly impact their psychological comfort. Data was collected using the SD scales and POMS of 60 male and 60 female participants after they watched a video of four waterscape facilities. Participants deemed the video clip of a fountain waterscape to be artificial and linked it with changeable images that increased their vigor. The video clip of waterfall stimulated various impressions (e.g., vital, liked, active, etc.) and changed participant' mood states by increasing their vigor and decreasing fatigue. The video clip of the pond yielded familiar impressions, produced less free images, and decreased tension among participants. Finally, the video clip of the stream stimulated quiet and comfortable images as well as reduced negative feelings of anger, confusion, and depression among participants. Furthermore, males experienced more positive effects than females, regardless of the type of waterscape facility. The study findings indicate that the four different waterscape facilities influenced participants' mood states. Additionally, the psychological effects differed by gender. The data suggest that landscape planners need to carefully consider their choice of waterscape facility when designing green spaces to ensure that the space is psychologically comforting to users.