• 설비공학논문집
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• 제17권5호
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• pp.410-417
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• 2005

The cooling performance of a transcritical $CO_{2}$ cycle varies significantly with a variation of refrigerant charge amount. In this study, the performance of the $CO_{2}$ system was measured and analyzed by varying refrigerant charge amount at a standard test condition. Besides, the losses of the major components in the $CO_{2}$ system were estimated by evaluating entropy generation with refrigerant charge amount. The losses in the expansion device and the gascooler show the major portion of the total loss. For undercharging conditions, the expansion loss dominates the overall system performance, while the gascooler loss increases significantly with an increase of refrigerant charge amount.

• 설비공학논문집
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• 제8권2호
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• pp.208-218
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• 1996

Performance of a VM heat pump is considerably affected by various losses, such as enthalpy dump, reheat loss, pumping loss, conduction loss and shuttle loss. A second-order analysis model of VM heat pumps, which allows consideration of the major losses, was presented. Actual heat transfer rates for heat exchangers were calculated from the heat transfer rates obtained by the adiabatic analysis and various losses. New effective temperatures of heat exchangers were calculated from the actual heat transfer rates and the mean heat transfer coefficients until there was no appreciable change in the effective temperatures. Effects of design parameters, such as phase angle, swept volume ratio, regenerator length and speed on heating capacity, cooling capacity and COP were shown.

• Journal of Korean Society for Atmospheric Environment
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• 제20권E2호
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• pp.61-68
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• 2004

Aerosol losses in a 100L Tedlar$^{(R)}$ bag were investigated for the aerosols with number median diameter of 0.05 ${\mu}{\textrm}{m}$ and number concentration of 6.4 ${\times}$ 10$^4$ cm$^{-3}$ . Over a 1 hr period, loss of particles in the bag is apparent, and the volume decrease with time is significant. The number concentration, surface area, and volume concentration of the aerosols decreased to 34, 50, and 52% of the initial value in 30 min, respectively. This indicates that deposition to the walls was the main loss process for aerosols in the Tedlar$^{(R)}$ bag. Theoretical calculations showed that coagulations and deposition by diffusion and gravitational sedimentation would not change aerosol characteristics significantly, and the electrical force was the dominant loss process for particles in the Tedlar$^{(R)}$ bag over a 1 hr period.eriod.

• Journal of Preventive Medicine and Public Health
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• 제22권4호
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• pp.528-541
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• 1989

The purpose of this study was to identify and measure the economic costs and benefits due to smoking in Korea. Cigarette smoking is a major cause of morbidity and mortality. In addition to the health risks of smoking, there are important economic consequences. A complete assessment of the economics of smoking requires evaluation of various health, economic, and intangible parameters, including benefits as well as costs of both the production and consumption of tobacco. In this article we focus on costs resulting from the health effects of smoking (expenditures for medical care and the value of productive output lost to morbidity, and premature mortality among smokers), since economic benefits from tobacco industry is offset by expenditures for purchasing tobacco. Two distinct methodologies will be applied to measure the economic costs of smoking cigarette, the human capital and willingness-to-pay approaches. This article used the former method. In 1985, total economic losses due to smoking was estimated as 505.7 billion won, which was composed of morbidity losses 64.9 billion won mortality losses 429.1 billion won and indirect costs 11.7 billion won.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.192-194
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• 2015

The growing size and complex process in construction project recently leads to increase risk and the losses as well. Even though researchers have identified the major risk indicators, there is lack of comprehensive and quantitative research for identifying the relationship between the risk indicators and economic losses associated with construction projects. To address this shortage of research, this study defines risk indicators and create a framework to assess the influence of economic losses from the indicators. An insurance company's claim payout record was accepted as the dependent variable to reflect the real economic losses. Based on the claims, we categorized the causes and results of accidents. To establish framework, built environment vulnerability indicators and geographical vulnerability indicators were employed as the risk indicators. A Pearson correlation analysis was adopted to validate the relationship with loss ratio and risk indicators. Consequently, this framework and its results may offer significant references for under writers of insurance companies and loss prevention activities.

• Journal of Biosystems Engineering
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• 제8권2호
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• pp.26-38
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• 1983

Binder harvesters introduced to Korea were originally designed to be used for Japonica varieties which are highly resistant to shattering. In order to improve the performance of the binder to Indica varieties which are easily shattered and have shorter stem, mechanical modifications of the binder are inevitable. Shattering losses of the binder can be classified into two major parts; one incurred before and one after binding operations. The latter has been evaluated as great as the former. Previous studies indicated that the high discharge losses resulted from a great impact force of the discharge arm on the rice bundle during the discharge process. This study was intended to theoretically analyze the discharge mechanism of four-bar linkage. For this purpose, two commercially available binder harvesters having a four-bar linkage as a discharge mechanism were analyzed. Using the results from the motion analysis and the other structural constraints of the machines, they were modified and experimentally compared with the machines without modification to see whether any decrease in grain losses was obtained. The results obtained in this study are summarized as follows: 1. The path, velocity and acceleration of discharge arm were computer analyzed by vector analysis. Using results of the analysis and intrinsic constraints of the binder, discharge mechanism was modified to reduce the impact force on bundle by discharge arm in the range where the discharge performance was not deteriorated. This modification of the discharge mechanism could be done with an aid of four-bar linkage synthesis technique. As a result, average velocity and acceleration of the discharge arm during the discharge process were reduced respectively by 19 percent and 33 percent for binder A, and 17 percent and 35 percent for binder B. 2. Through the modification of the discharge mechanism, discharge losses of binder A were reduced by 42-56 percent for Milyang 23, Poongsan and Hangang chal, and discharge losses of binder B were reduced by 13-20 percent for Milyang 23 and Poongsan. 3. Discharge losses were decreased as the bundle size became larger and the size effect on the decrease rate appeared more significant in the binders with modifications than in those without modifications.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.142-149
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• 2000

It is required that the indoor-noise level of KHST (Korean high speed train) should be lower than 66 ㏈(A) at 350 km/h. In this study, the indoor-noise level of KHST has been predicted to determine the maximum allowable sound power levels of major noise sources. It is found that the indoor-noise requirement for KHST can be met by increasing the transmission losses of the floor and side-wall structures as well as by lowering the sound power levels of two major noise sources including the motor fans.

• 한국콘텐츠학회논문지
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• 제17권4호
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• pp.95-107
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• 2017

최근 기후변화의 영향에 의해 재난의 규모가 점차 대형화 되어감에 따라 사회 및 국민경제에 미치는 영향이 증대되고 있다. 그러나 기존의 재해손실 통계는 직접적인 인명피해를 제외하면 물리적인 피해에만 국한되어 있어 피해규모가 과소 집계되는 문제가 있다. 이로 인해 피해자의 보상 및 정부 지자체의 재난정책 수립에도 장애요소로 작용되고 있다. 따라서 본 연구는 그동안 간과되어 온 사회경제적 직 간접 손실의 피해항목을 조사 분석하여 국내의 실정에 맞는 기본통계 항목을 도출하는 데 그 목적이 있다. 이를 위해 국내외의 재해피해 통계 현황과 선행연구 등을 검토하여 사회경제적 직 간접 손실에 대한 개념 및 프레임워크를 설정하고, 예비 통계항목을 도출하였다. 이후, 통계항목의 선별기준을 정립하여 최종 통계항목을 선정하였다. 본 연구의 결과는 풍수해의 사회경제적인 영향과 피해규모를 산정하고 예측하는 기술개발 연구에 기초자료로 활용될 수 있다.

• Asian-Australasian Journal of Animal Sciences
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• 제24권5호
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• pp.723-738
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• 2011

Contamination of agricultural crops by mycotoxins results in significant economic losses for grain producers and, when consumed, it can cause reduced growth and health in a wide range of animal species. Hundreds of mycotoxin producing molds exist, however each has a different frequency and pattern of occurrence, as well as differences in the severity of the diseases (mycotoxicoses) they cause. Among the mycotoxins considered to be major contaminates are aflatoxin, deoxynivalenol, fumonisin, ochratoxin, and zearalenone. Although a multitude of species can be harmed by consumption of these mycotoxins, swine appear to be the most commonly affected commodity species. The swine industry can thus experience great losses due to the presence of mycotoxin contamination in feeds. Subsequently, recognition and prevention of mycotoxicoses is extremely important and dependent on adequate grain sampling and analysis methods pre-harvest, as well as effective strategies post-harvest to reduce consumption by animals. The aim of this review is to provide an overview of the major mycotoxin contaminants in grains, to describe methods of analysis and prevention to reduce mycotoxicoses in swine and other animals, and finally to discuss how mycotoxins directly affect swine production.

• International Journal of Fluid Machinery and Systems
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• 제10권1호
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• pp.1-8
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• 2017

Bifurcation refers to wye division of penstock to divide the flow symmetrically or unsymmetrically into two units of turbine for maintaining economical, technical and geological substrates. Particularly, water shows irrelevant behavior when there is a sudden change in flow direction, which results into the transition of the static and dynamic behavior of the flow. Hence, special care and design considerations are required both hydraulically and structurally. The transition induced losses and extra stresses are major features to be examined. The research on design and analysis of bifurcation is one of the oldest topics related to R&D of hydro-mechanical components for hydropower plants. As far as the earlier approaches are concerned, the hydraulic designs were performed based on graphical data sheet, head loss considerations and the mechanical analysis through simplified beam approach. In this paper, the multi prospect approach for design of Bifurcation, incorporating the modern day's tools and technology is identified. The hydraulic design of bifurcation is a major function of dynamic characteristics of the flow, which is performed with CFD analysis for minimum losses and better hydraulic performances. Additionally, for the mechanical design, a simplified conventional design method as pre-estimation and Finite Element Method for a relevant result projections were used.