• Title/Summary/Keyword: center loss

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A Review on the Emission Sources of Ammonia and the Factors Affecting Its Loss

  • Das, Piw;Sa, Jae-Hwan;Kim, D.S.;Kim, K.H.;Jeon, E.C.
    • Journal of Korean Society for Atmospheric Environment
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    • v.23 no.E2
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    • pp.47-56
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    • 2007
  • Among all the nitrogen species present in the atmosphere, ammonia forms a considerable portion along with the nitrogen oxides. The major sources of atmospheric ammonia are animal feedlot operations including emission from excreta of domestic animals and agricultural activities, followed by emission from synthetic fertilizers, biomass burning and to some lesser extent, fossil fuel combustion. Ammonia emission factor, expressed as the weight of ammonia per unit weight, volume, or duration of the activity emitting it, is generally used in developing emission estimates for emission inventories. The factors determining ammonia loss from soil or from manures are the temperature, pH, humidity, precipitation and the velocity of wind above it.

A Finite-element Method Analysis of Electromagnetic Noise Absorption in a Coplanar Transmission Line Integrated with a Magnetic Film

  • Sohn, Jae-Cheon;Han, Suk-Hee;Lim, Sang-Ho
    • Journal of Magnetics
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    • v.11 no.2
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    • pp.90-94
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    • 2006
  • A finite-element method is used to analyze loss generation and electromagnetic noise absorption characteristics of a coplanar waveguide transmission line integrated with a magnetic thin film. Parameters used in the analysis are the electrical resistivity of the magnetic layer and the thickness of both magnetic and insulating layers. The results indicate that L-C resonance is the main loss mechanism of the electromagnetic noise absorption.

The Effect of Balance Weight on the Lubrication and Friction Characteristics of Crankshaft System (크랭크샤프트계의 윤활 및 마찰 특성에 미치는 밸런스 웨이트의 영향)

  • Jo, Myeong-Rae;O, Dae-Yun;Han, Dong-Cheol
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.8
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    • pp.1585-1590
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    • 2002
  • This paper reports on the balance weight effect on the lubrication and friction characteristics of crankshaft system. To determine the main bearing loads, the crankshaft was treated as statically determinate system. Four and eight-balance weight crankshafts were considered, and minimum oil film thickness and friction loss were calculated. The main bearing loads were increased in the four-balance shaft due to the increasing of unbalanced rotating mass at No. 1 and 3 main bearing sides. The minimum oil film thickness of four-balance shaft became thinner than eight-balance, and friction loss was increased.

Distribution Feeder Reconfiguration Using Heuristic Rules (경험적 규칙을 이용한 배전계통의 재구성기법)

  • Cho, Si-Hyung;Choi, Byoung-Youn;Woo, Kwang-Bang
    • Proceedings of the KIEE Conference
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    • 1991.07a
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    • pp.363-365
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    • 1991
  • This paper presents a method for feeder reconfiguration in order to operate distribution systems efficiently using heuristic rules. The reconfiguration method presented here not only eliminates various abnormal states but also achieves minimum power loss and optimum load balance of the distribution feeders under normal operating condition transfering loads from one feeder to anoter applying the experiences of the experts. To implement the method effectively, a best-first tree searching strategy based on heuristics is used to evaluate the various load transfer alternatives. The development of a rule-based system aimed at the reduction of the search space is presented as a means of implementing the best-first searching strategy. The results of the computer simulation of the above procedure are as follows; 1) achieving minimum power loss of the distribution feeder adopting the optimum load transfer alternative. 2) Enhencing system reliability and achieving load balance through rational allocation of the feeder loads.

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An Application Example of SEA for the KOMPSAT-1 Satellite Model (KOMPSAT-1 위성구조체에 대한 SEA 적용사례)

  • Jeong C. H.;Ih J. G.;Kim Y. K.;Kim H. B.
    • Proceedings of the Acoustical Society of Korea Conference
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    • autumn
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    • pp.211-214
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    • 2004
  • 이륙과 음속 통과시 랜덤진동형태의 음향/진동환경에 노출되는 위성체의 음향/진동시험은 시제품을 완성한 후에 슨1행되므로 않은 시행착오를 겪거나, 과다한 안전계수를 사용하여 불필요한 무게증가 등의 문제점을 가지고 있다. 이러한 문제점을 극복하기 위하여 통계적 에너지 해석법 (Statistical Energy Analysis)을 이용한 선행 해석이 필요하다. 본 연구에서는 KOMPSAT-1 (Korea Multi-Purpose Satellite-1) 위성체의 SDM (Structural Dynamic Model)에 대하여 SEA 해석을 수행하였다. 감쇠 손실 인자 (Damping Loss Ffactor)는 단판을 분리하여, 연성 손실 인자(Coupling Loss Factor)는 SDM모델 하부의 두 샌드위치 패널을 분리하여 실험적으로 산정하였다.

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Physical therapy and Occupational therapy on the hand infections (수부 감염에 대한 물리치료와 작업치료)

  • Jung, Seok;Kim, Jeong-Ja
    • Journal of Korean Physical Therapy Science
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    • v.6 no.1
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    • pp.861-877
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    • 1999
  • The hand is a very specialized organ that functions to obtain information and to execute motor acts essential to human interaction with the environment. Loss of hand function through infections affects the mechanical tasks that the hand performs and psychological adjustments to their disability. Infection is a disastrous complication of hand injuries and adequacy of circulation is of greatest importance to prevention of infection. Careful debridement, incision, and adequate drainage and antibacterial treatment are of great importance. Optimal care of the infected hand demands that carefully surgical care, early postoperative exercises and other therapy. Hand rehabilitation has grown as a specialty area of both physical and occupational therapy. It is essential that the surgeon and therapist work together, and communicate freely-all of which generally require daily contact. Treating the psychological loss suffered by the patient with a hand infections is an integral part of the rehabilitation therapy as well. Treatment techniques, Whether thermal modalities or specifically designed exercises, are used as a bridge to reach a further goal of returning to functional performance.

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A Consideration on the Minimum Transmission Loss for the Intraoffice Call Path Based on the Listener Echo (수화자 반향을 고려한 자국내 최소 전송손실에 대한 고찰)

  • Jang, Chung-Ryong;Hong, Jin-Woo
    • Proceedings of the KIEE Conference
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    • 1987.07b
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    • pp.894-897
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    • 1987
  • Listener echos, which arise in multiple 4-wire loop connections(MLC) during the evolving switched telephone network, impare voice-band data signal transmission performance. This paper first shows the calculation method of the total number of listener echo loops over N 4-wire physical loops and presents the additative law for listener echos. It next demonstrates that about 4 dB should be ensured to Eke the transmission loss of intraoffice call path be minimum for the voice-band data service in a digital local switch.

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Performance Analysis of an ATM Multiplexer with Multiple QoS VBR Traffic

  • Kim, Young-Jin;Kim, Jang-Kyung
    • ETRI Journal
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    • v.19 no.1
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    • pp.13-25
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    • 1997
  • In this paper, we propose a new queuing model, MMDP/MMDP/1/K, for an asynchronous transfer mode(ATM) multiplexer with multiple quality of service(QoS) variable bit rate (VBR) traffic in broadband-integrated services digital network (B-ISDN). We use the Markov Modulated Deterministic Process(MMDP) to approximate the actual arrival process and another MMDP for service process Using queuing analysis, we derive a formula for the cell loss probability of the ATM multiplexer in terms of the limiting probabilities of a Markov chain. The cell loss probability can be used for connection admission control in ATM multiplexer and the calculation of equivalent bandwidth for arrival traffic, The major advantages of this approach are simplicity in analysis, accuracy of analysis by comparison of simulation, and numerical stability.

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Loss Cut of Air-Cooled Waterwheel Generator with AC Variatle Speed Drive for Cooling Fan Motor(s) (교류 가변속 장치의 냉각팬 적용에 의한 수력 발전기 손실 저감)

  • Hur, Sung-Kwang;Rhew, Hong-Woo;Park, Min-Ho
    • Proceedings of the KIEE Conference
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    • 1989.07a
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    • pp.579-582
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    • 1989
  • The air-cooled waterwheel generator has a fan connected to waterwheel shaft or motor driven fan or fans. The fans are operated at constant speed, constant input, regardless of generator loss which is varied according to generator output and coolant the perature. Energy savings may he possible if the cooling air flow is controlled according to generato output and air temperature depending on season. The simulation and experience have been done on the 22.6 KVA Waterwheel generator by using AC variable speed drive. The results gave us los cut of generator.

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Microwave Photonics Frequency-Converted Link Using Electroabsorption Devices

  • Wu, Y.;Shin, D.S.;Chang, W.S.C.;Yu, P.K.L.
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.4 no.1
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    • pp.74-81
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    • 2004
  • We propose a novel scheme to transmit high center frequency RF signals using electroabsorption devices (EADs) as frequency converters at the transmitter and the receiver. In this approach frequency heterodyning is employed for obtaining high center frequency. With the EAD as a detector/mixer at the receiver we demonstrated a smaller conversion loss than that of the conventional modulator/mixer. With EAD as a modulator/mixer at the transmitter and with two heterodyned lasers to generate an optical local oscillator (LO), we demonstrated a large reduction (${\sim}23dB$) in conversion loss, and the transmission is not limited by the optical saturation of the EAD. This transmission scheme has optical single-side-band transmission feature which greatly relieves the fiber dispersion effect.