• Journal of Environmental Impact Assessment
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• v.18 no.6
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• pp.321-330
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• 2009

Spatiotemporal changes in the thermal environment in a large city, Seoul, Korea were analyzed using a thermal index, perceived temperature (PT), to standardize the weather conditions. PT is a standard index for the thermal balance of human beings in thermophysiological environment. For the analysis of PT, the data from long-term monitoring and intensive observations in and around the inner-city stream called 'Cheonggye' in Seoul, were compared with a reference data from the Seoul weather station. Long-term data were monitored by installing two automatic weather stations at 66m (S1) and 173m (S2) away from the center of the stream. Through the analysis of the data during the summer of 2006 and intensive observation periods, it was revealed that the stream's effects on the PT extended up to the distance of the S1 site. In winter, the increase of the PT between pre- and post-restoration was stronger at S1, which was nearer than S2 from the stream. These results suggest that PT can be used as an effective model in analyzing the changes of the thermal environment in relation with the changes of water surface areas.

• Journal of Preventive Medicine and Public Health
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• v.29 no.1 s.52
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• pp.103-112
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• 1996

We studied the association of nonspecific bronchial hyperresponsiveness with general characteristics, exposure concentration, respiratory symptoms, chest x-ray findings, past histories and pulmonary function. We determined bronchial hyperresponsiveness by methacholine challenge test. And we conducted a respiratory symptom questionnaire and performed spirometry on 111 workers occupationally exposed to isocyanates in various industries. About 21.6% of subjects had bronchial hyperresponsiveness. No significant differences were observed between the hyperresponsive and non-responsive group with respect to age, sex, employment period, height, and smoking histories. Cough and breathlessness were significantly associated with the bronchial hyperresponsiveness. The hyperresponsive group had more experience of bronchitis and asthma in the past than the non-responsive group. The lower $FEV_1\;and\;FEV_1%$ were closely related with bronchial hyperresponsiveness. Bronchial hyperresponsiveness seems to be associated with some of respiratory symptoms, past histories and pulmonary function parameters in workers exposed to isocyanates.

• Journal of Preventive Medicine and Public Health
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• v.26 no.1 s.41
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• pp.86-95
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• 1993

To investigate perception and attitude toward Group Health Management and Service System for Small and Medium Industries, a survey using self-administered questionnaire was conducted to a part of industries in Inchon, at October 1992. Major dependent variables were perception, attitude, and practice related with Group Health Management and Service System; these variables were measured by 3-point Likert like scale consisted of 7, 5, and 5 items, respectively. Data were collected in 149 industries,72.7% out of 205. Perception nab slightly high, 1.25; attitude was some positive, 1.46; and practice was some passive,0.94. Major determinants of perception, attitude, and practice were sex and age of industry's health manager; perception influenced upon attitude, and perception and attitude had positive effect upon practice. To activate Group Health Management and Service System, it is necessary to develop education and promotion programs for industry's health managers of small and medium industries.

• Journal of Chest Surgery
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• v.26 no.12
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• pp.920-925
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• 1993

Extra-anatomic bypass was proposed by Freeman in 1952 and has been used for patient with lower extremity arterial occlusion who had very high operative risk, especially elderly or severly illed patient.We had performed 14 cases of extra-anatomic bypasses from Jan. 1991 till July 1993 and having been following up them. Their results were summarized as follow. Among total 14 patients, 13 was male. Their mean age was 64.8 years old, ranged from 48 to 80. The most common complaint was pain on lower limb and they visited hospital 6.1 months in average after onset of symptom. Frequently, they were associated with systemic diseases such as generalized atherosclersis, hypertension, diabetes mellius, etc. Axillary artery was used as donor artery in 8 cases and crossover femoro-femoral or femoro-popliteal bypass was performed in 6 cases. Postoperative complications were notedd in 8 cases so their morbidity rate was 42.8%. Except for two contraindicated cases, one or more anticoagulants were used routinely . Among them, combined use of aspirin and persantine was most commonly applied.After bypass graft, nine cases were occluded beteween 10 and 53 months. So their average duration of freedom from reocclusion was 35.7 months and 3-year patency rate was 63%.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.600-605
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• 2009

A general purpose viscous flow solver Ansys CFX is used to study a Savonius type wave energy converter in a 3D numerical viscous wave tank. This paper presents the results of a computational fluid dynamics (CFD) analysis of the effect of blade configuration on the performance of 3 bladed Savonius rotors for wave energy extraction. A piston-type wave generator was incorporated in the computational domain to generate the desired incident waves. A complete OWC system with a 3-bladed Savonius rotor was modeled in a three dimensional numerical wave tank and the hydrodynamic conversion efficiency was estimated. The flow over the rotors is assumed to be two-dimensional (2D), viscous, turbulent and unsteady. The CFX code is used with a solver of the coupled conservation equations of mass, momentum and energy, with an implicit time scheme and with the adoption of the hexahedral mesh and the moving mesh techniques in areas of moving surfaces. Turbulence is modeled with the k.e model. Simulations were carried out simultaneously for the rotor angle and the helical twist. The results indicate that the developed models are suitable to analyze the water flows both in the chamber and in the turbine. For the turbine, the numerical results of torque were compared for all the cases.

• Tribology and Lubricants
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• v.34 no.1
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• pp.9-15
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• 2018

Modern high-performance automotive turbochargers (TCs) implement ceramic hybrid angular contact ball bearings in series with squeeze film dampers (SFDs) to enhance transient responses, thereby reducing the overall emission levels. The current study predicts the rotordynamic responses of the commercial automotive TCs (compressor wheel diameter = ~53 mm, turbine wheel diameter = ~43 mm, and shaft diameter at the bearing locations = ~7 mm) supported on ball bearings and SFDs for various design parameters of SFDs, including radial clearance, axial length, lubricant viscosity, and rotor imbalance conditions (i.e., amplitudes and phase angles) while increasing rotor speed up to 150 krpm. This study validates the predictive rotor finite element model against measurements of mass, polar and transverse moments of inertia, and free-free mode natural frequencies and mode shapes. A nonlinear rotordynamic model integrates nonlinear force coefficients of SFDs to calculate the transient responses of the TC rotor-bearing system. The predicted results show that SFD radial clearances, as well as phase angles of rotor imbalances, have the paramount effect on the dynamic responses of TC shaft motions.

• Economic and Environmental Geology
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• v.29 no.4
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• pp.529-541
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• 1996

The granitic rocks, so called Masanite, characterized by the micrographic, mylmekitic and perthitic textures, and zonal structure of the plagioclase in the Masan, Changwon and Jinhae areas belong to normal granite and granodiorite based on the modal analysis. These petrographic features strongly suggest the shallow emplacement of the plutons which are defined a typical calc-alkaline suite and I-type granitoids. The pressures of emplacement of the granitic plutons using the amphibole geobarometer were calculated to be 1.2kbar in the Masan area and 1.4kbar in the Changwon area. Their amphibole-plagioclase equilibrium temperatures were obtained to be $638^{\circ}C$ for the former ones and $724^{\circ}C$ for the latter. Homogenization temperatures and salinities for the type HI and IV fluid inclusions in quartz range from 298 to $541^{\circ}C$ (av. $425^{\circ}C$), and 10.5 to 34.6 wt.% NaCl (av. 28.2 wt.% NaCl), respectively. Gas compositions of the granitic rocks with fairly high $CO_2$ concentration relative to CH, correspond to the magnetite series granite of the mantle source. The terminology of the Masanite is not recommended usage. Because it is hard to discriminate in terms of petrological and petrogenetical characteristics between the Masanite and the Bulguksa granites in the Kyeongsang basin.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.9 no.3
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• pp.125-131
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• 1997

In order to analyze the feasibility of the drain layer construction method, which is one of the beach protection methods, a hybrid model is constructed by combining the wave model and the seepage flow model. The used wave model is the analytic solution given by Shuto (1972). and the seepage flow model is used by Richards equation which governs the saturated-unsaturated flow in the porous media. It is concluded by the sensitivity analysis of the hybrid model that the most sensitive parameter in the flow field within the beach is the saturated hydraulic conductivity. The developed hybrid model will be efficiently used in the analysis of the parameter when the drain layers are constructed in the beach, if the field datas are obtained more.

• Journal of Applied Reliability
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• v.13 no.1
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• pp.45-53
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• 2013

In this paper, we analyze the failure mechanism of the washer pump to find what is the failure cause in the road environment. The statistics show the field common failure mode is inner corrosion. The failure mechanism is assumed that the inner part of washer pump is corroded due to inflow of moisture through vent hole. To prevent the failure, we can think a method that is covering the vent hole. In general, the vent hole is designed to play an important role in an automobile parts. So, we need to prove the vent hole is not necessary. The first purpose of this paper is to make sure that the vent hole does not affect the durability of washer pump using the analysis of operating condition. The second purpose is to compare the durability properties if the vent hole is covered.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.5
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• pp.58-63
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• 2008

Cold rolled and high strength steel were used for vehicle bodys to satisfy environmental regulation and improve fuel ratio. This paper presented a method far determining the fatigue life of cold rolled steel sheet EZNCEN and high strength steel sheet HS40R spot weldment used in vehicles. We can estimate the fatigue life of the spot weldments from the MSC/FATIGUE using the finite element method. The maximum load is found in the nugget part of both surfaces. The cold rolled steel and the high strength steel showed the maximum stress 746MPa and 730MPa in the effective nugget part when the weld current was 8KA and 7KA, respectively. Also the some weld current of the cold rolled steel and high strength steel is applied, the fatigue life of high strength steel is obtained about four times longer than the cold rolled steel.