• Title/Summary/Keyword: Second law efficiency

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Performance analysis of an organic Rankine cycle for ocean thermal energy conversion system according to pinch point temperature difference (핀치포인트온도차에 따른 해양온도차발전용 유기랭킨사이클의 성능분석)

  • Kim, Jun-Seong;Kim, Do-Yeop;Kang, Ho-Keun;Kim, You-Taek
    • Journal of Advanced Marine Engineering and Technology
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    • v.40 no.6
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    • pp.476-483
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    • 2016
  • An organic Rankine cycle for ocean thermal energy conversion system is a generating cycle using the temperature difference between surface water and deep water of the ocean. The working fluid is an important factor in the thermodynamic performance of an organic Rankine cycle. There is pinch point analysis as thermodynamic analysis of an organic Rankine cycle. This study performed a thermodynamic performance analysis according to variation in the pinch point temperature difference in heat exchangers and variation of outlet temperature of heat source and heat sink. It analyzed the thermodynamic performance by applying seven types of simple working fluids in a simple Rankine cycle for ocean thermal energy conversion that was designed according to pinch point analysis. As a result of the performance analysis, cycle irreversibility and total exergy destruction factor more decreased, and second law efficiency more increased in the lower pinch point temperature difference and temperature variation of heat source and heat sink in heat exchangers. In addition, the irreversibility changed greatly at a point that occurred in the thermodynamic variation. Among the selected working fluids, RE245fa2 showed the best thermodynamic performance, and the performance of all working fluids was observed to be similar. It needs a strict theoretical basis about diverse factors with thermodynamic performances in selecting heat exchangers and working fluids.

The Measurement and Analysis by Free Space Scatter Dose Distribution of Diagnostic Radiology Mobile Examination Area (영상의학과 이동검사 영역의 공간선량 분포에 대한 측정 및 분석)

  • Kim, Sung-Kyu;Son, Sang-Hyuk
    • Korean Journal of Digital Imaging in Medicine
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    • v.11 no.1
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    • pp.5-13
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    • 2009
  • There are several reasons to take X-ray in case of inpatients. Some of them who cannot ambulate or have any risk if move are taken portable X-ray at their wards. Usually, in this case, many other people-patients unneeded X-ray test, family, hospital workers etc-are indirectly exposed to X-ray by scatter ray. For that reason I try to be aware of free space scatter dose accurately and make the point at issue of portable X-ray better in this study. kVp dose meter is used for efficiency management of portable X-ray equipment. Mobile X-ray equipment, ionization chamber, electrometer, solid water phantom are used for measuring of free space scatter dose. First of all the same surroundings condition is made as taken real portable X-ray, inquired amount of X-ray both chest AP and abdomen AP most frequently examined and measured scatter ray distribution of two tests individually changing distance. In the result of measuring horizontal distribution with condition of chest AP it is found that the mAs is decreased as law of distance reverse square but no showed mAs change according to direction. Vertical distribution showed the mAs slightly higher than horizontal distribution but it isnt found out statistical characteristic. In abdomen AP, compare with chest AP, free space scatter dose is as higher as five-hundred times and horizontal, vertical distribution are quite similar to chest AP in result. In portable X-ray test, in order to reduce the secondary exposure by free space scatter dose first, cut down unnecessary portable order the second, set up the specific area at individual ward for the test the third, when moving to a ward for the X-ray test prepare a portable shielding screen. The last, expose about 2m apart from patients if unable to do above three ways.

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The Internationalization Strategy of Small-and-Medium-Sized Enterprises in Korea through Internationl Network (국제(國際) 네트워크를 통한 한국(韓國) 중소기업(中小企業) 국제화전략(國際化戰略)에 관한 연구(硏究))

  • Oh, Se-Young;Lee, Jung-Youn
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.13
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    • pp.767-804
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    • 2000
  • International network strategy is intended to examine the validity of existing network-centered theories in order to ascertain why small-and medium-sized enterprises are useful as a strategic correspondence to the internationalization trend. Small-and medium-sized enterprises can be estimated as being vital majorities in terms of their flexibility to meet changable conditions in international marketing compared with the conglomerates Therefore, their dependency on a few conglomerates for the international economy can be diverged. Generally, the successful internationalization of industries can be derived from the creation of suitable strategies for its competence and quality with the effective correction and completion of its strategy and tactics through mistakes. The internationalization strategy of small-and medium-sized enterprises should not be the reckless pursuit of internationalization that depends only on the increase of investment or the simple induction of the other conglomerates strategic models, but it should be accomplished through the evolution and practice of the concrete strategies that will be more proper for the enterprise's property and efficiency. The results of analyses with proof can be summarized with two effects in large in the process of internationalization of domestic small-and medium-sized enterprises. First, the capacity for internationalization of firms results from a long-term training procedure and continuous development of managing activities. Then in time this becomes an important element for the small-and medium-sized firms in terms with its position targeted international trading. However, the domestic enterprises are showing their abilities in the international competition in quantity, and trying to establish relationships between the enterprises through international networks. Second, statistics might not be meaningful in part because of the lack of data for analysis. It seems that more useful results will be derived from obtaining and utilizing sufficient information and from establishing an inter-relationship between the small-and medium-sized enterprises which are investing in foreign companies.

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The way to achieve Universal Health Coverage: Focusing on the Historical and Cultural Context of Health Care Sector in Vietnam (보편적 건강보장을 향한 노정 : 베트남 보건의료 부문의 역사·문화적 맥락을 중심으로)

  • BEAK, Yong Hun
    • The Southeast Asian review
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    • v.28 no.1
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    • pp.173-218
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    • 2018
  • This study focuses on the healthcare sector in Vietnam which is promoting universal health insurance for the achievement of Universal Health Coverage (UHC) under Sustainable Development Goals (SDGs). The purpose of this study is to examine the characteristics of the reform process of the health care system and the law on health insurance through the historical and cultural contexts and its implications from the perspective of development. Based on the three dimensions of UHC - extension of protection for population, provision of various medical services, and financial protection, the current status of the Vietnam healthcare sector is summarized respectively as follows. First, according to the revised Health Insurance law which came into effect in 2015, the mandatory health insurance premiums are calculated based on household units. Second, there is a medical network that can provide preventive and healthcare services centered on primary health care facilities, for example commune health stations (trạm y $t{\hat{e}}$ $X{\tilde{a}}$). Third, out-of-pocket expenditure is still a large proportion although public spending has increased and private spending has decreased since the enforcement of the health insurance law and various schemes. Vietnam is currently striving towards a universal health care system. The development of institutions and systems should be designed in a way that is appropriate for the members of the society rather than efficiency. This article findings shed light on the role of social values, family culture, and informal institutions.

A Study on the Realization of Infrastructure for Electronic Trade (전자무역 기반사업의 구현에 관한 연구)

  • Lee, Bong-Soo
    • International Commerce and Information Review
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    • v.12 no.1
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    • pp.55-73
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    • 2010
  • The thesis examines new innovation of various aspect to overcome lots of problems which come by when we execute simplification of trade procedure and administration fairly. Practical implications regarding the innovation of electronic trade infrastructure are as follows. First, it will propel the standardization of electronic trade section in the technical side and the construction atmosphere of international authentication system must be created. The work process should be redesigned in order to implement export-import procedures that meet the relevant standards. Second, the improvement of system for electronic process is necessary in the law and institutional aspect. In order to eliminate any obstacles to the trade procedure, clearer legal grounds regarding legitimate controls and minimum necessity must be established. Also, laws should be revised to admit mutual recognition among certification organizations, in lieu of international agreement-based mutual recognition between government. Third, the detailed improvement for the integration of the electronic trade infrastructure will be demanded. Additionally, user-centered quality management protocols should be established via connections with the systems already existing in governmental bodies. Fourth, various trade institution should harmonized and interconnected with other partners through mutual cooperation for standardization of operational system. A system which can monitor and remotely diagnose and resolve system errors should be established to provide tailor-made service and improve operational efficiency. At the same time, it is necessary to build a cooperative system to share information and promote comprehensive management for efficient operation.

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The politic suggestion and the design of integrate-construction model for installation of the residential IT facility. (구내 정보통신설비를 위한 정책제안과 통합구축모델 설계)

  • Kang, Young-Chang;Lim, Sang-Chul;Kim, Sun-Hyung
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.5
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    • pp.845-853
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    • 2009
  • This study recognize the problems about the High-speed IT building certification system and the technical standards of telecommunication facility, broadcasting public receiving facility including Home-network facility which are installed at apartments for the successful building of the Ubiquitous city that the government is driving and suggested a sweeping change of the housing law interrelated for making up a housing efficiency grade-display system and systematizing the maintenance by solutions. Also, presented the integrate-construction model designs separately of the residential IT line about the buildings applied to technical standards, the building acquired second grade below of High-speed IT building and the building when the above solutions get to he systematized.

A Study on Law and Standards for Promotion of Aftermarket (애프터시장(판매후시장) 활성화를 위한 국내외 법률 및 표준에 대한 연구)

  • Choi, Sun;Hwang, SangKyu
    • Journal of Environmental Science International
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    • v.22 no.8
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    • pp.1063-1072
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    • 2013
  • To overcome the ecosystem-crisis of resource depletion and climate change, we should maintain and develop a 'Sustainability' of our society. 'After-market' is defined like this : any market where customers who buy one product or service are likely to buy a related follow-on product. This is related to a automotive, electric and electronic, and remanufacturing industry. 'After-market' will be helpful for reuse and recycling of resources aspects, cost and economic efficiency, low-carbon, climate protection, and new industries and job creation effects, To promote 'After-Market', we need to guarantee the quality of products. In this regard, we refer and introduce a new standard, for example, BS8887, PAS141 and ISO20245 etc. In order to promote 'After-Market', first of all, product quality assurance and safety must be demonstrated in the process of reuse. Second, many aspects of a device that protects the rights of consumers to be provided. And third, the related laws and standards should be reviewed. Finally, original manufacturer's awareness for environmental protection and resource conservation and government's institutional support are needed.

Prediction of Permeability for Braided Preform (브레이드 프리폼의 투과율 계수 예측)

  • Youngseok Song;Youn, Jae-Roun
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2003.04a
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    • pp.184-187
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    • 2003
  • Complete prediction of second order permeability tensor for three dimensional circular braided preform is critical to understand the resin transfer molding process of composites. The permeability can be predicted by considering resin flow through the multi-axial fiber structure. In this study, permeability tensor for a 3-D circular braided preform is calculated by solving a boundary problem of a periodic unit cell. Flow field through the unit cell is obtained by using a 3-D finite volume method (FVM) and Darcy's law is utilized to obtain permeability tensor. Flow analysis for two cases that a fiber tow is regarded as impermeable solid and permeable porous medium is carried out respectively. It is found that the flow within the intra-tow region of the braided preform is negligible if inter-tow porosity is relatively high but the flow through the tow must be considered when the porosity is low. To avoid checkerboard pressure field and improve the efficiency of numerical computation, a new interpolation function for velocity variation is proposed on the basis of analytic solutions. Permeability of the braided preform is measured through a radial flow experiment and compared with the permeability predicted numerically.

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A Study on Institutionalization of the Rent-A-Driver Industry from the Point of View at the Creative Industries

  • OH, Moon-Kap;YOUN, Myoung-Kil
    • Korean Journal of Artificial Intelligence
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    • v.7 no.2
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    • pp.1-8
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    • 2019
  • This paper, we argue that sector in terms of the creative industries the need to the institutional settle of the rent-a-driver business; the industry could create more than 200,000 jobs, the effect is to bring out the about 4 trillion underground economy and Can be interpreted industry, which contributes to reduce social costs, ranging from 1.7 trillion won to 5.7 trillion per year. Through institutionalization of policy should support. Observation and in-depth interviews were conducted with the law and the president of the rent-a-driver business company. The operating system should be improved. the rent-a-driver business, for the formulation of the work ethic and education is desperately needed. The effect socio-economic contribution effect of the rent-a-driver business industry can be summarized as follows. First, it is an industry that has an operating system utilizing state-of-the-art technology and equipment, and the convergence of creative industries to comply with the market. Second, the effect appears as an industry that creates jobs for the populace to replace the social security system, social safety net is considered as an industry. Third, this is an industry that can be self-reliant in the short term at least political support, the industry is considered in the industry to maximize the effectiveness and efficiency of the support policy.

Performance Evaluation of an Oxy-coal-fired Power Generation System - Thermodynamic Evaluation of Power Cycle (순산소 석탄 연소 발전 시스템의 성능 평가 - 동력 사이클의 열역학적 해석)

  • Lee, Kwang-Jin;Choi, Sang-Min;Kim, Tae-Hyung;Seo, Sang-Il
    • Journal of the Korean Society of Combustion
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    • v.15 no.2
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    • pp.1-11
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    • 2010
  • Power generation systems based on the oxy-coal combustion with carbon dioxide capture and storage (CCS) capability are being proposed and discussed lately. Although a large number of lab scale studies for oxy-coal power plant have been made, studies of pilot scale or commercial scale power plant are not enough. Only a few demonstration projects for oxy-coal power plant are publicized recently. The proposed systems are evolving and various alternatives are to be comparatively evaluated. This paper presents a proposed approach for performance evaluation of a commercial 100 MWe class power plant, which is currently being considered for 'retrofitting' for the demonstration of the concept. The system is configurated based on design and operating conditions with proper assumptions. System components to be included in the discussion are listed. Evaluation criteria in terms of performance are summarized based on the system heat and mass balance and simple performance parameters, such as the fuel to power efficiency and brief introduction of the second law analysis. Also, gas composition is identified for additional analysis to impurities in the system including the purity of oxygen and unwanted gaseous components of nitrogen, argon and oxygen in air separation unit and $CO_2$ processing unit.