• Title/Summary/Keyword: Time Shortening

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A Study on the Prediction for the Performance and the Size of the Vehicle Radiator (자동차 엔진 방열기의 뱅각 성능 및 방열 면적 예측에 관한 연구)

  • 박찬국;이종범;엄호룡;정우인
    • Transactions of the Korean Society of Automotive Engineers
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    • v.5 no.3
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    • pp.117-127
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    • 1997
  • To maintain the reasonable temperature in the engine is very important to keep the steady combustion state of engine and to prevent increasing of lubricant consump- tion, deteriorating of lubricant, shortening of the life time of engine and decreasing of material strength. The method of energy balance for devided elements of radiator is considered to analyse the performance of radiator. Th data of engine test and vehicle cooling tunnel test are applied to program for calculation of radiator outlet temperature, and this result is compared with outlet temperature of vehicle cooling tunnel test. As a result, the radiator outlet temperature by numerical analysis agrees well with that by experiment. It is concluded that this simulation program is available in developing the cooling system for a new car.

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Influence of Differential Moisture Distribution on SRC Column Shortening

  • Seol Hyun-Cheol;Kim Jin-Keuna;Kim Yun-Yonga;Kwon Seung-Heea
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.05a
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    • pp.423-426
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    • 2005
  • Steel reinforced concrete (SRC) columns, which are widely employed in high-rise buildings, exhibit particular time-dependent behavior due to creep and shrinkage of the concrete, and this behavior may cause problems related to serviceability and structural stability. SRC columns also exhibit a time-dependent, cross-sectional relative humidity distribution that differs from reinforced concrete (RC) columns, due to the presence of an inner steel plate, which interferes with the moisture diffusion of concrete. This differential moisture distribution of SRC columns may reduce the drying shrinkage and the drying creep as contrasted with RC columns. Therefore, we propose that the differential moisture distribution be taken into account to accurately predict SRC column shortening.

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Measured and Predicted Column Shortening of a Tall Reinforced Concrete Building (고층 콘크리트 건물의 기둥축소량 계측연구)

  • 김원상;조한욱;오정근;염경수
    • Journal of the Korea Concrete Institute
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    • v.11 no.3
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    • pp.161-170
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    • 1999
  • The KLCC Petronas Tower 2, one of the world tallest twin reinforced concrete towers constructed in Kuala Lumpur, Malysia, was instrumented during construction for the measurement of vertical time-dependent deformation of columns and corewall. Field measurements were made by means of vibrating wire strain gauges at the corewall, tower and bustle perimeter columns at selected floor levels of the building. Parallel to this observation, laboratory tests were performed on concrete cylinders made in the field in order to obtain the variations of concrete compressive strengths, elastic moduli, strains of creep and shrinkage with time. Monitored vertical deformations are in a good agreement with the prediction based on actual construction sequence and concrete properties from laboratory tests, as well as the analytical results reflected in actual column compensation of the building.

A Study on the Heat Performance of Single Layered Bubble Sheet Using Phothothermal Materials (광발열 소재를 활용한 1중 버블시트의 발열성능 검토)

  • Lee, Hyeon-Jik;Hu, Yun-Yao;Lee, Seung-Min;Han, Jun-Hui;Kin, Jong;Han, Min-Cheol
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2023.11a
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    • pp.223-224
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    • 2023
  • This study compared the curing temperature of the bubble sheet and the photothermal insulation sheet incorporating carbon-based photothermal materials to reduce concrete curing time as a part of shortening construction period. As a result of the experiment, bubble sheet with photothermal material B is judged to be effective in shortening the curing time under hot environment.

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Changes of Cheese Components and Texture Characteristics in Cheese Ripening by Fusant Developed by Lactic Acid Bacteria (융합주에 의한 치즈 숙성시 성분변화와 조직 특성)

  • 송재철;김정순;박현정;신환철
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.26 no.6
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    • pp.1077-1085
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    • 1997
  • This study was carried out to elucidate the utilization of the fusant for shortening the ripening time by making an observation of the microstructure and the profile of component change. In ripening cheese, moisture content of the sample treated with tested strain is not a remarkable difference among the test samples. With an increase of the ripening time, L. helveticus showed the highest increase in protein content, followed by fusant, and then L. bulgaricus. The fat content of all starters was gradually decreased while it was it was rapidly decreased after 7 days. The pH of all starters was gradually decreased when the ripening time increased. The titratable acidity was greatly increased between a 9th day and a 15th day ripening. In investigating the light microscopic microstructure of ripened cheese samples, the sample treated with fusant indicated little difference from the other starters in decomposition of protein and fat components by microbial enzymes. In SEM observation, the structure of all cheese samples was uniform and the rough texture was converted into smooth texture by the interaction of cheese components and the abscission of single bond in casein matrix when the ripening time is increased. The fusant showed similar results in the examination of component change and its microstructure compared with the other starters. Therefore, it was revealed that the fusant can be partially used as a cheese starter instead of conventional starters by replacing them or combining them together with the other starters for shortening the ripening time.

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Effects of anesthesia on echocardiograms in myocardial infarcted dogs (심근경색 유발견에서 마취가 심초음파에 미치는 영향)

  • Yoon, Jung-hee;Sung, Jai-ki
    • Korean Journal of Veterinary Research
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    • v.37 no.3
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    • pp.669-685
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    • 1997
  • The present study was performed to evaluate the effects of xylazine and tiletamine + zolazepam on echocardiograms before and after experimental myocardial infarctions in clinically normal dogs taken preliminary examinations related to cardiac function. The results are as follows. With xylazine administration, left ventricle end-diastolic dimension, left ventricle end-systolic dimension, left atrium/aorta, ejection time and velocity of circumferential fiber shortening increased and mitral valve CD slope, % delta D decreased(p<0.01). In tiletamine+zolazepam administered group, interventricular septum amplitude(p<0.01), mitral valve DE slope(p<0.05) and ejection time(p<0.01) decreased and left atrium/aorta, ejection time also decreased compared with xylazine group(p<0.01). In 48 hours after experimental myocardial infarction group, anterior aortic wall amplitude decreased compared with control, xylazine, tiletamine + zolazepam group, respectively(p<0.01). Posterior aortic wall amplitude decreased compared with control(p<0.01). Left ventricle end systolic dimension increased compared with control and tiletamine + zolazepam group, respectively(p<0.01). Left ventricular posterior wall end systolic dimension decreased compared with control(p<0.01). Left ventricular posterior wall amplitude decreased compared with control and tiletamine+zolazepam group(p<0.01). Left atrium/aorta decreased compared with xylazine group(p<0.01). % thickening left ventricular posterior wall decreased compared with control(p<0.05). % delta D decreased compared with control and tiletamine+zolazepam group(p<0.01). Ejection time decreased compared with xylazine(p<0.01). Velocity of circumferential fiber shortening increased compared with control and tiletamine + zolazepam group(p<0.01). With xylazine administration 48 hours after experimental myocardial infarction, anterior aortic wall amplitude, posterior aortic wall amplitude decreased compared with control(p<0.01). Left ventricle end-diastolic dimension increased compared with control(p<0.01). Left ventricle end-systolic dimension increased compared with control and tiletamine + zolazepam group, respectively(p<0.01). Left ventricular posterior wall end-systolic dimension and left ventricular posterior wall end-diastolic dimension decreased compared with control(p<0.01). Left atrium/aorta decreased compared with xylazine group(p<0.01). % thickening left ventricular posterior. wall(p<0.05) and % delta D(p<0.01) decreased compared with control. Velocity of circumferential fiber shortening increased compared with tiletamine + zolazepam group(p<0.01). With tiletamine + zolazepam administration 48 hours after experimental myocardial infarction, anterior aortic wall amplitude decreased compared with control, xylazine and tiletamine+zolazepam group, respectively(p<0.01). Posterior aortic wall amplitude decreased compared with control(p<0.01). Left ventricle end-systolic dimension increased compared with control and tiletamine+zolazepam group(p<0.01). Left ventricular posterior wall end-systolic dimension, left ventricular posterior wall end-diastolic dimension and interventricular septum amplitude decreased compared with control(p<0.01). Left atrium/aorta decreased compared with xylazine group(p<0.01). % delta D decreased compared with control and tiletamine + zolazepam group(p<0.01). Ejection time decreased compared with xylazine group and velocity of circumferential fiber shortening increased compared withtiletamine+zolazepam group(p<0.01). Conclusively, echocardiography was proved to be a useful, diagnostic, non-invasive and simple method for establishing the diagnosis of myocardial infarction and evaluating the effects of drug on cardiac function before and after myocardial infarction.

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Surgical Treatment of Chronic Tophaceous Gout in the 1st Metatarso-Phalangeal Joint (족부 제 1중족 족지 관절에 발생한 만성 결절성 통풍의 수술적 치료)

  • Lee, Tae-Hun;Nam, Il-Hyun;Ahn, Gil-Yeong;Lee, Yeong-Hyeon;Lee, Yong-Sik;Choi, Young-Deuk;Lee, Hee-Hyung
    • Journal of Korean Foot and Ankle Society
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    • v.22 no.4
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    • pp.156-160
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    • 2018
  • Purpose: Chronic tophaceous gout is a painful and disabling inflammatory disease. Surgical treatment for chronic tophaceous gout is very difficult with many complications. This study evaluated the efficacy of shortening scarf osteotomy on the treatment of chronic tophaceous gout in the 1st metatarso-phalangeal (MTP) joint. Materials and Methods: From January 2006 to December 2015, 14 patients (19 cases) who underwent axial shortening scarf osteotomy for chronic tophaceous gout were reviewed. All patients were male. The average age at the time of surgery was 59.6 years (42~66 years). The minimum follow-up was 24 months. Total removal of the tophi mass with the adhered medial capsule of the 1st MTP joint was attempted. Axial shortening scarf osteotomy was done on the 1st metatarsal shaft. The visual analogue scale (VAS) for pain and the American Orthopaedic Foot and Ankle Society (AOFAS) forefoot score was assessed preoperatively and postoperatively. The range of motion (ROM) of the 1st MTP joint was also compared pre- and postoperatively. Results: The average size of the extracted tophaceous mass was 32 mm. The mean amount of the length of metatarsal shortening was 4.9 mm. The mean ROM of the 1st MTP joint was improved from $30.4^{\circ}$ to $62.3^{\circ}$. The mean AOFAS forefoot score improved from 51.4 to 86.6 points. The mean VAS for pain improved from 4.6 to 0.3 points. Conclusion: The axial shortening scarf osteotomy used on chronic tophaceous gout could reconstruct the 1st MTP joint with an improved ROM and was free of pain. Axial shortening scarf osteotomy is suggested as a useful and effective method for the treatment of chronic tophaceous gout.

Musculotendon Model to Represent Characteristics of Muscle Fatigue due to Functional Electrical Stimulation (기능적 전기자극에 의한 근육피로의 특성을 표현하는 근육 모델)

  • Lim, Jong-Kwang;Nam, Moon-Hyon
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.8
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    • pp.1046-1053
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    • 1999
  • The musculotendon model is presented to show the declines in muscle force and shortening velocity during muscle fatigue due to the repeated functional electrical stimulation (FES). It consists of the nonlinear activation and contraction dynamics including physiological concepts of muscle fatigue. The activation dynamics represents $Ca^{2+}$ binding and unbinding mechanism with troponins of cross-bridges in sarcoplasm. It has the constant binding rate or activation time constant and two step nonlinear unbinding rate or inactivation time constant. The contraction dynamics is the modified Hill type model to represent muscle force - length and muscle force - velocity relations. A muscle fatigue profile as a function of the intracellular acidification, pH is applied into the contraction dynamics to represent the force decline. The computer simulation shows that muscle force and shortening velocity decline in stimulation time. And we validate the model. The model can predicts the proper muscle force without changing its parameters even when existing the estimation errors of the optimal fiber length. The change in the estimate of the optimal fiber length has an effect only on muscle time constant in transient period not on the tetanic force in the steady-state and relaxation periods.

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Innovation Strategy for Shortening The Lead Time of The New Product Development Using 6 Sigma (6시그마를 이용한 신제품개발기간 단축을 위한 혁신전략 - 기업 사례를 중심으로)

  • Hwang, In-Keuk;Kim, Jin-Ho;Park, Yong-Bok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.7 no.2
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    • pp.224-230
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    • 2006
  • As business competition gets together, there is much pressure on product development service organizations and manufacturing to become more productive and efficient. Product developers need to create innovative products in less time, even though the products may be very complex. To get this purpose, Six sigma methodology can be used. Six sigma is a strategic approach that works across all processes, all products, and all industries. The purpose of this paper is to develop the innovation strategy for shortening the lead time of the new product using six sigma method.

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Energy Effective Tag Anti-collision Protocol for Mobile RFID System (에너지 효율적인 모바일 RFID용 태그 충돌방지 프로토콜)

  • Cho, Yang-Hyun;Kook, Joong-Gak
    • Journal of the Korea Society of Computer and Information
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    • v.17 no.2
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    • pp.207-214
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    • 2012
  • This paper is to improve an identification ratio of tags by analyzing Slotted ALOHA, Dynamic Slotted ALOHA, Binary-tree and Query-tree and shortening the tag identification time in mobile RFID. Also, it enables the stable information transmission of tags by saving backscattering power of tags through shortening of identification time. As a result, this increases the available time of the battery and accessibility to a RFID service. For this, we proposed the energy-efficient tag anti-collision protocol for mobile RFID. The proposed scheme shows advanced result in identification time and collision counts. This scheme may be the first attempt for the mobile anti-collision.