• Title/Summary/Keyword: Transfer

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토양 중 디젤 성분의 생분해에 있어서 mass-transfer 영향

  • 조한나;염익태;박주양
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2002.09a
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    • pp.203-206
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    • 2002
  • 토양 오염의 주된 원인인 디젤은 휘발성과 용해도가 낮아 생물학적 처리법이 많이 이용된다. 생물학적 처리에서 Bioavailability 는 생분해의 속도에 영향을 미치며 유효성평가에 있어 중요하다. 디젤로 오염된 토양의 생분해 특성 및 Bioavailability를 평가하기 위하여 생분해 실험과 mass transfer 실험을 수행하였다. 생분해 속도와 mass transfer 속도의 비교를 통해 생분해 초기에는 mass transfer에 의해 그 속도가 부분적으로 제한을 받으나, 일정시간 후에는 mass transfer 속도에 의해 생분해 속도가 결정되어짐을 알 수 있었다. Multi -component 인 디젤 성분에서의 mass transfer 의 영향을 알기 위해 각 성분별에 따라 조사한 결과, linear H.C 성분과 고 휘발성 성분은 생분해 속도가 초기에는 mass transfer 에 의해 부분적으로 제한되고 후에 mass transfer 에 의해 결정되어지나, tracked H.C 성분과 저휘발성 성분은 전체적으로 mass transfer 에 의해 생분해 속도가 제한되고 있음을 알 수 있었다.

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A Study on the Laminar Flow Field and Heat Transfer Coefficient Distribution for Supercritical Water in a Tube (초임계상태의 물에 대한 관 내 층류유동장 및 열전달계수 분포특성에 관한 연구)

  • 이상호
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.15 no.9
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    • pp.768-778
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    • 2003
  • Numerical analysis has been carried out to investigate laminar convective heat transfer in a tube for supercritical water near the thermodynamic critical point. Fluid flow and heat transfer are strongly coupled due to large variations of thermodynamic and transport properties such as density, specific heat, viscosity, and thermal conductivity near the critical point. Heat transfer characteristics in the developing region of the tube show transition behavior between liquid-like and gas-like phases with a peak in heat transfer coefficient distribution near the pseudocritical point. The peak of the heat transfer coefficient depends on pressure and wall heat flux rather than inlet temperature and Reynolds number, Results of the modeling provide convective heat transfer characteristics including velocity vectors, temperature, and the properties as well as the heat transfer coefficient. The effect of proximity to the critical point is considered and a heat transfer correlation is suggested for the peak of Nusselt number in the tube.

A Numerical Study on the Laminar Flow Field and Heat Transfer Coefficient Distribution for Supercritical Water in a Tube

  • Lee Sang-Ho
    • International Journal of Air-Conditioning and Refrigeration
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    • v.13 no.4
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    • pp.206-216
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    • 2005
  • Numerical analysis has been carried out to investigate laminar convective heat transfer at zero gravity in a tube for supercritical water near the thermodynamic critical point. Fluid flow and heat transfer are strongly coupled due to large variation of thermodynamic and transport properties such as density, specific heat, viscosity, and thermal conductivity near the critical point. Heat transfer characteristics in the developing region of the tube show transition behavior between liquid-like and gas-like phases with a peak in heat transfer coefficient distribution near the pseudo critical point. The peak of the heat transfer coefficient depends on pressure and wall heat flux rather than inlet temperature and Reynolds number. Results of the modeling provide convective heat transfer characteristics including velocity vectors, temperature, and the properties as well as the heat transfer coefficient. The effect of proximity on the critical point is considered and a heat transfer correlation is suggested for the peak of Nusselt number in the tube.

The Mediating Effects of Bidirectional Knowledge Transfer on System Implementation Success

  • Kim, Jong Uk;Kim, Hyo Sin;Park, Sang Cheol
    • Asia pacific journal of information systems
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    • v.25 no.3
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    • pp.445-472
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    • 2015
  • Although knowledge transfer between two different parties occurs in IS development projects, the majority of prior studies focused on knowledge transfer from IT consultants to clients. Considering two parts of knowledge transfer in IS development projects, we must consider both 'where knowledge is transferred from' and 'where it is transferred to'. Therefore, in this study, we attempt to describe two different routes of knowledge transfer, such as knowledge transfer from an IT consultant to a client and knowledge transfer from a client to an IT consultant. In this regard, we have examined the effect of two different routes of knowledge transfer on system implementation success in IS development project. Specifically, we adopted the knowledge stock-flow theory to examine the causal relationship between IT consulting firms and clients in terms of knowledge transfer and eventual system implementation success. Survey data collected from 213 pairs of individuals (both clients and IT consultants) were used to test the model using three different analytic approaches such as PLS (partial least squares) and two types of mediated regression techniques. We found that knowledge transfers partially mediated both the relationships between IT consultants' IT skills (project members' business knowledge) and system implementation success. Furthermore, the effects of each knowledge transfer were distinguished by depending on the types of system, such as ERP or groupware. Our attempts have significant implications for both research and practice given the importance of effective knowledge transfer to IT consulting.

Research on heat transfer coefficient of supercritical water based on factorial and correspondence analysis

  • Xiang, Feng;Tao, Zhou;Jialei, Zhang;Boya, Zhang;Dongliang, Ma
    • Nuclear Engineering and Technology
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    • v.52 no.7
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    • pp.1409-1416
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    • 2020
  • The study of heat transfer coefficient of supercritical water plays an important role in improving the heat transfer efficiency of the reactor. Taking the supercritical natural circulation experimental bench as the research object, the effects of power, flow, pipe diameter and mainstream temperature on the heat transfer coefficient of supercritical water were studied. At the same time, the experimental data of Chen Yuzhou's supercritical water heat transfer coefficient was collected. Through the factorial design method, the influence of different factors and their interactions on the heat transfer coefficient of supercritical water is analyzed. Through the corresponding analysis method, the influencing factors of different levels of heat transfer coefficient are analyzed. It can be found: Except for the effects of flow rate, power, power-temperature and temperature, the influence of other factors on the natural circulation heat transfer coefficient of supercritical water is negligible. When the heat transfer coefficient is low, it is mainly affected by the pipe diameter. As the heat transfer coefficient is further increased, it is mainly affected by temperature and power. When the heat transfer coefficient is at a large level, the influence of the flow rate is the largest at this time.

A Study on the Mass Transfer from a Square Cylinder Using Naphthalene Sublimation Technique (나프탈렌승화법을 이용한 사각관 주위에서의 물질전달에 관한 연구)

  • 유성연
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.14 no.5
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    • pp.1300-1310
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    • 1990
  • Naphthalene sublimation technique is employed to investigate the mass transfer processes from a square cylinder at various Reynolds numbers and various angles of attack. Distribution of the local mass transfer coefficients on each face of the cylinder changes dramatically with the angle of attack. Such variation of local mass transfer rates closely connected with the complex flow phenomena such as stagnation, acceleration, separation, reattachment and vortex shedding. The average Sherwood number has a minimum value at 12.deg.-13.deg., and a maximum value at a=20.deg.-25.deg. A comparison of present mass transfer measurement with other heat transfer measurements, using the heat/mass transfer analogy, shows good agreement in average transfer rates, same trend but notable differences in local values. Therefore, naphthalene sublimation technique can be adopted to explore heat transfer processes in the complex flow situations, which is considered to be hardly possible with the conventional heat transfer measurements.

Does Village Fund Transfer Address the Issue of Inequality and Poverty? A Lesson from Indonesia

  • ARHAM, Muhammad Amir;HATU, Rauf
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.10
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    • pp.433-442
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    • 2020
  • This study investigates the impact of fiscal transfer, specifically the Village Fund Transfer, on rural income inequality and rural poverty. Studies on fiscal transfer offers contrasting outcomes, some argues that fiscal transfer suppresses wealth disparity, while others argue that it tends to widen disparity. This study employs descriptive analysis in estimating the elasticity of income inequality and poverty rate before and after the Village Fund Transfer. It develops multiple regressions model on panel datasets of 33 provinces in Indonesia before and after the implementation of Village Fund Transfer. This study suggests that the elasticity of income inequality is higher after the implementation of village fund transfer. Rural poverty tends to decline annually, however, the elasticity changes is lower after the implementation of village fund transfer. Furthermore, this study suggests that village fund transfer is insignificant in coping with the issue of income inequality, while education and the level of labor productivity of agricultural sector appears to be the determinant factor in tackling the issue of income inequality in the rural areas. This study further reveals the significance of village fund transfer in suppressing the rural poverty rate. This study also highlights the significance of human resources quality and agricultural sector in reducing poverty rate in rural areas.

A-Study on The Heat Transfer Performance of Evaporator Heat Transfer Tube for Absorption Chiller (흡수식 냉온수기 증발기용 전열관의 전열성능에 관한 연구)

  • Kwon, Oh-Kyung;Cha, Dong-An;Yun, Jae-Ho;Kim, Hyo-Sang
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.21 no.4
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    • pp.215-221
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    • 2009
  • The objectives of this paper are to measure the heat transfer and pressure drop of the heat transfer tube for an evaporator of absorption system applications. Five types of heat transfer tubes with different shape and heat transfer area are tested in the present experiment. Heat transfer and pressure drop performance of heat transfer tubes are measured in various operating conditions, and compared each other. The results show that the heat transfer coefficient of thermoexcel notch tube increases about 79.6% and 45.3% at the film Reynolds number 69.7 compared with that of bare tube and low fin tube, respectively. The thermoexcel notch tube is show the best performance considering pressure drop and heat transfer coefficient.

Immediate Toe-to-Hand Transfer in Acute Hand Injuries (급성 수부 손상시 즉시 족지 전이술)

  • Woo, Sang-Hyun;Kim, Hak-Soo
    • Archives of Reconstructive Microsurgery
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    • v.11 no.1
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    • pp.19-28
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    • 2002
  • From 1994-2001, 25 mutilated digits were reconstructed with immediate toe-to-hand transfer in acute hand injury in 21 patients. There were 15 cases of great toe-to-hand transfer(partial great toe transfer 8 cases, modified wrap-around procedure 2 cases, and trimmed great toe transfer 2 cases) for thumb reconstruction, 2 cases of second toe transfer for index reconstruction, and 4 cases of simultaneous two toe-to-hand transfer(great toe & second toe transfer 1 case, bilateral second-toe transfer 2 cases, combined second & third toe transfer 1 case) for reconstruction of multiple digit amputations. Two cases of emergency exploration(2/25, 8%) were successfully salvaged. The incidence of emergency exploration and postoperative infection was not significantly different from that of the elective toe-to-hand transfer cases. Duration of industrial insurance coverage was 225 days, which is much shorter than that of elective cases. Among 43% of patients maintained their original job even after injury and immediate toe-to-hand transfer. The subjective satisfaction self- assessment scores of aesthetic appearance and function on the new reconstructed thumb were 80 and 88 in average, respectively, over a total score of 100. These were higher than those of reconstruction of other digits, but lower than those of elective reconstruction. The donor site after harvest of the great toe was mostly unsatisfied in a view of appearance. Immediate toe-to-hand transfer provides many advantages over elective procedure in acute hand injuries such as single stage reconstruction, shortened convalescent period, early return to work and efficient socio-economic factor. Furthermore because there were no significant differences in success rate, frequency of complications or ultimate functional result, immediate toe-to-hand transfer is a safe and reliable procedure in case of limited indications for acute digits loss.

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A model of a relative evaluation of the transfer distance between two modes (환승센터의 두 수단간 환승거리의 상대적 적정성 평가)

  • Cha, Dong-Deuk;O, Jae-Hak;Park, Wan-Yong;Park, Seon-Bok
    • Journal of Korean Society of Transportation
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    • v.27 no.1
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    • pp.35-42
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    • 2009
  • One of the problems we face up at the time of planning or improving a transportation transfer facility is which modes and how close we have to put together. The goal here is to keep the connecting transportation mode as close as possible to the prime transit mode, so people travel a minimum transfer path, a distance from one mode to another. Too much a physical separation between modes will limit, even with an intensive improvement of the component links, the level of service of a transfer path as a whole. This study defined a transfer path as the whole stretch of the distance from an arrival point of one mode to the departure point of the connecting mode. The transfer path was divided into three typical segments as side walk, stairways, and indoor corridors. Preference surveys were made for each of these segments, resulting in relative resistance. The sum of individual segments weighted with the relative resistance will make a transfer resistance of the path, which in turn constitutes a transfer utility function together with the overall satisfaction score obtained by the interview survey. The transfer utility function has been utilized to evaluate the transfer distance between modes.