• Title/Summary/Keyword: Cool-Down

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The Characteristics for BNCT facility in Hanaro Reactor

  • Soheigh Suh;Lee, Dong-Han;Ji, Young-Hoon;Lee, Dong-Hoon;Yoo, Seong-Yul;Rhee, Chang-Hun;Rhee, Soo-Yong;Jun, Byung-Jin
    • Proceedings of the Korean Society of Medical Physics Conference
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    • 2002.09a
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    • pp.161-163
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    • 2002
  • The BNCT(Boron Neutron Capture Therapy) facility has been developed in Hanaro(High-flux Advanced Neutron Application Reactor), a research reactor of Korea Atomic Energy Research Institute. A typical tangenial beam port is utilized with this BNCT facility. Thermal neutrons can be penetrated within the limits of the possible maximum instead of being filtered fast neutrons and gamma rays as much as possible using the silicon and bismuth single crystals. In addition to, the liquid nitrogen (LN$_2$) is used to cool down the silicon and bismuth single crystals for the increase of the penetrated thermal neutron flux. Neutron beams for BNCT are shielded using the water shutter. The water shutter was designed and manufactured not to interfere with any other subsystem of Hanaro when the BNCT facility is operated. Also, it is replaced with conventional beam port plug in order to cut off helium gas leakage in the beam port. A circular collimator, composed of $\^$6/Li$_2$CO$_3$ and polyethylene compounds, is installed at the irradiation position. The measured neutron flux with 24 MW reactor power using the Au-198 activation analysis method is 8.3${\times}$10$\^$8/ n/cm$^2$ s at the collimator, exit point of neutron beams. Flatness of neutron beams is proven to ${\pm}$ 6.8% at 97 mm collimator. According to the result of acceptance tests of the water shutter, the filling time of water is about 190 seconds and drainage time of it is about 270 seconds. The radiation leakages in the irradiation room are analyzed to near the background level for neutron and 12 mSv/hr in the maximum for gamma by using BF$_3$ proportional counter and GM counter respectively. Therefore, it is verified that the neutron beams from BNCT facility in Hanaro will be enough to utilize for the purpose of clinical and pre-clinical experiment.

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Detection of Thermal Ratcheting Deformation for Cylindrical Shells by Ultrasonic Guided Wave (유도초음파를 이용한 원통형 쉘의 열 라체팅 변형 탐지)

  • Joo, Young-Sang;Lee, Hyeong-Yeon;Kim, Jong-Bum;Park, Chang-Gyu;Lee, Jae-Han
    • Journal of the Korean Society for Nondestructive Testing
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    • v.26 no.5
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    • pp.297-305
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    • 2006
  • The thermal ratcheting deformation at the reactor baffle and upper internal structure of the liquid metal reactor (LMR) can occur due to movement of the hot sodium free surface. In in-service inspection of reactor internals of LMR, a new inspection technique should be developed for the detection of the thermal ratcheting damage. In this study, an inspection technique using ultrasonic guided wave is proposed for the detection of the thermal ratcheting damage of cylindrical vessels. A 316L stainless steel cylindrical shell specimen has been prepared. The thermal ratchet structural tests were cyclically performed by heat-up up to $550^{\circ}C$ with steep temperature gradients along the axial direction after cool-down by cooling water. Ultrasonic guided wave propagation has been characterized by analysis of dispersion curve of the stainless steel plate. The zero-order antisymmetric $A_0$ guided wave has been selected as the optimal mode for detection of the ratcheting deformation. It is confirmed that the thermal ratcheting deformation can be detected by the measurement of transit time difference of circumferentially propagated $A_0$ guided waves.

Three-dimensional Numerical Prediction on the Evolution of Nocturnal Thermal High (Tropical Night) in a Basin

  • Choi, Hyo;Kim, Jeong-Woo
    • International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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    • v.25 no.1
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    • pp.57-81
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    • 1997
  • Numerical prediction of nocturnal thermal high in summer of the 1995 near Taegu city located in a basin has been carried out by a non-hydrostatic numerical model over complex terrain through one-way double nesting technique in the Z following coordinate system. Under the prevailing westerly winds, vertical turbulent fluxes of momentum and heat over mountains for daytime hours are quite strong with a large magnitude of more than $120W/\textrm{m}^2$, but a small one of $5W/\textrm{m}^2$ at the surface of the basin. Convective boundary layer (CBL) is developed with a thickness of about 600m over the ground in the lee side of Mt. Hyungje, and extends to the edge of inland at the interface of land sea in the east. Sensible heat flux near the surface of the top of the mountain is $50W/\textrm{m}^2$, but its flux in the basin is almost zero. Convergence of sensible heat flux occurs from the ground surface toward the atmosphere in the lower layer, causing the layer over the mountain to be warmed up, but no convergance of the flux over the basin results from the significant mixing of air within the CBL. As horizontal transport of sensible heat flux from the top of the mountain toward over the basin results in the continuous accumulation of heat with time, enhancing air temperature at the surface of the basin, especially Taegu city to be higher than $39.3^{\circ}C$. Since latent heat fluxes are $270W/\textrm{m}^2$ near the top of the mountain and $300W/\textrm{m}^2$ along the slope of the mountain and the basin, evaporation of water vapor from the surface of the basin is much higher than one from the mountain and then, horizontal transport of latent heat flux is from the basin toward the mountain, showing relative humidity of 65 to 75% over the mountain to be much greater than 50% to 55% in the basin. At night, sensible heat fluxes have negative values of $-120W/\textrm{m}^2$ along the slope near the top of the mountain and $-50W/\textrm{m}^2$ at the surface of the basin, which indicate gain of heat from the lower atmosphere. Nighttime radiative cooling produces a shallow nocturnal surface inversion layer with a thickness of about 100m, which is much lower than common surface inversion layer, and lifts extremely heated air masses for daytime hours, namely, a warm pool of $34^{\circ}C$ to be isolated over the ground surface in the basin. As heat transfer from the warm pool in the lower atmosphere toward the ground of the basin occurs, the air near the surface of the basin does not much cool down, resulting in the persistence of high temperature at night, called nocturnal thermal high or tropical night. High relative humidity of 75% is found at the surface of the basin under the moderate wind, while slightly low relative humidity of 60% is along the eastern slope of the high mountain, due to adiabatic heating by the srong downslope wind. Air temperature near the surface of the basin with high moisture in the evening does not get lower than that during the day and the high temperature produces nocturnal warming situation.

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The Effect of Muscle Fatigue Reduction and Heart Rate Recovery According to Whole Body Vibration after Gait Exercise in the Young Female (성인여성의 보행 운동 후 전신진동이 근피로도 해소와 심박회복율에 미치는 영향)

  • Kang, Seung-Rok;Min, Jin-Young;Hong, Cheol-Un;Kwon, Tae-Kyu
    • Science of Emotion and Sensibility
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    • v.19 no.1
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    • pp.3-10
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    • 2016
  • This research was to investigate the effect of fatigue reduction and heart rate recovery (HRR) according to whole body vibration (WBV). 20 healthy participants were recruited and divided into vibration group (VG) and none vibration group (NVG). VG was group with provided vibration and NVG was group without vibration. They exercised slope gait with 8.5 degree and 4km/h during 30min. They rested on the chair type vibrator during 30min. The vibration consists of 10hz as frequency and 5mm as amplitude. We measured the lactate in the blood and HRR before, immediately after exercise and after rest session. The results showed that lactate level in VG the more decreased at 95.2%. The result of HRR was similar including recovery at 50.67% in VG. The WBV with stimulated vessel in muscle assisted the recovery function by reducing the excess post-exercise oxygen consumption (EPOC) quickly and improving blood circulation. The rest with WBV could provide efficient cool-down exercise for elderly and women without other physical activities after exercise.

The Effects of a Cardiac Rehabilitation Program on Health Behavior Compliance, Cardiovascular Function, and Quality of Life for the Patients with Ischemic Heart Disease (심장재활 프로그램이 허혈성 심장환자의 건강행위 이행, 심혈관 기능 및 삶의 질에 미치는 효과)

  • 조현숙;김광주
    • Journal of Korean Academy of Nursing
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    • v.30 no.3
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    • pp.560-570
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    • 2000
  • This study is aimed at developing a cardiac rehabilitation program and enlightening the effects of the program on patient's health behavior compliance, cardiovascular functional capacity, and quality of life. Using a quasi-experimental approach the nonequivalent control group pretest - posttest design was accepted for this study. The subjects of this study consisted of 55 patients with ischemic heart disease at the Cardiac Center of 'G' Hospital located in Inchon from May 1, 1998 to April 30, 1999. The patients were divided into two groups: the experimental group, which participated in the cardiac program with 30 patients and 25 patients of a control group were not involved in the program. There were two phases in the cardiac rehabilitation program: the first phase was a team approach education. It focused on reducing the risk of ischemic heart problems. The second phase was individual training by using a home based exercise program, which was comprised of 8 weeks, three sessions per week, 40-60 minutes per session, and followed by consultation. Every session involved 20-40 minutes of aerobic exercise at 40-60% of heart rate reserve, 11∼13 RPE and 10 minutes of warm-up and 10 minutes of cool-down exercises. The experimental tools for the study were the health behavior compliance scale developed by Lee, Yoon-hee (1992), and quality of life scale developed by McGirr et al.(1990). RPPsubmax were measured by the treadmill. The collected data was processed by SPSS and analyzed by χ²test and t-test. The results of this study were as follows: 1. The health behavior compliance in experimental group was significantly increased (t=5.091, p=.000) when compared to the control group. 2. RPPsubmax also decreased significantly in the experimental group when compared to the control group(t=-2.109, p=.040). 3. The quality of life significantly improved in the experimental group (t=3.853, p=.000) as compared to the control group. As the above results of this study revealed, the effectiveness of the cardiac rehabilitation program of the study was confirmed. It increased the health behavior compliance for reducing the risk of further coronary events, enhanced the cardiovascular functional capacity, and eventually improved the patient's quality of life.

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The Effects of Stretching Exercise to Musculoskeletal pain in the Community-Dwelling Farmers (일개 지역 농부에서 근골격계 통증에 대한 스트레칭 운동의 효과)

  • Chong, Bok-Hee;Kim, Jeong-Ja;Yang, Chung-Yong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.10
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    • pp.4523-4530
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    • 2011
  • This study aimed to evaluate the effects of stretching management on musculoskeletal joint pain in community indwelling elderly farmers. The study included 28 residents who lived in a rural community. All participants were assigned randomly to either the stretching group (n=13, $59.67{\pm}4.77$ year-old) or the control group (n=15, $61.44{\pm}10.41$ year-old). Respondents were interviewed by means of a structured questionnaire. Pain severity of 6 body areas caused by symptoms of work-related musculoskeletal disorders and pain severity on day time variations were measured by the visual analogue scale on a self-assessed questionnaire. The stretching group was administered stretching therapy (45 min, 2 sets, warming up and cool down, main exercise; total 19 stretching kinds of subset 5 fields) for 12 times for 4 weeks. There were no significant difference between the two groups in general social and pain characteristics. After 4 weeks of stretching, the stretching group showed significant improvements at almost all joint pain scores except arm/elbow, and day time variation scores of pain compared to both baseline scores, and with control group scores. These results showed that stretching therapy is one of the most useful modalities to manage musculoskeletal pain in community-based elderly farmers.

Effects of Using Prop for Con vergence Pilates Met Exercise on the Immunoglobulin in Middle-aged Women (소도구를 활용한 융복합 필라테스 매트운동이 중년여성의 면역글로블린에 미치는 영향)

  • Back, Soon-Gi
    • Journal of the Korea Convergence Society
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    • v.6 no.5
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    • pp.329-336
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    • 2015
  • In this study, Pilates mat exercise program three times a week for 8 weeks, 10 minutes for a warm up, 40 minutes of main exercise, and 10-minute cool down exercise using gadgetry to the middle aged women. Pilates exercise program when exercise intensity based on the instructions of the ACSM (2010) as 1-4 weeks 50-60% HRR, 5-8 weeks 61-70% HRR to give 50-70%, maintaining the strength of 4 weeks. Pilates exercise program by gadgetry has increased the strength of wireless heart rate meter (Polar Analyzer, Polar Electro of Finland) Karvonen (1979), proceed individual target heart exercise obtained as a way now to check your strength workout through individual conciousness. We estimated immunoglobulin change for Pilates mat exercise by gadgetry during 8-week. It showed the following conclusions. First, immunoglobulin IgA has been increased and Interaction effects has been showed thruough Pilates mat exercise programs for 8 weeks. Second, immunoglobulin IgG has been increased and showed Interaction effects has been showed thruough Pilates mat exercise programs for 8 weeks. Third, immunoglobulin IgM has been increased and showed Interaction has been showed effects thruough Pilates mat exercise programs for 8 weeks. Therefore, this study was conducted on a Pilates mat exercise using props immune function are positive hormonal changes, can prevent private for the disease and effective exercises that are the fodder.

Construction and Assembly of KSTAR Current Leads and the Helium Control System (KSTAR 전류인입선 및 헬륨냉매 제어시스템 제작 및 설치)

  • Song, N.H.;Woo, I.S.;Lee, Y.J.;Kwag, S.W.;Bang, E.N.;Lee, K.S.;Kim, J.S.;Jang, Y.B.;Park, H.T.;Hong, J.S.;Park, Y.M.;Kim, Y.S.;Choi, C.H.
    • Journal of the Korean Vacuum Society
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    • v.16 no.5
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    • pp.388-396
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    • 2007
  • KSTAR (Korea Superconducting Tokamak Advanced Research) current lead system (CLS) has a role to interconnect magnet power supply (MPS) in room temperature (300 K) and superconducting (SC) bus-line, electrically. For the first plasma experiments, it should be assembled 4 current leads (CL) on toroidal field (TF) current lead box (CLB) and 14 leads on poloidal field (PF) CLB. Two current leads, with the design currents 17.5 kA, and SC bus-lines are connected in parallel to supply 35 kA DC currents on TF magnet. Whereas, it could supply $20\;{\sim}\;26\;kA$ to each pairs of PF magnets during more than 350 s. At the cold terminals of the leads, there are joined SC bus-lines and it was constructed helium coolant control system, aside from main tokamak system, to protect heat flux through current leads and enhanced Joule heat due to supplied currents. Throughout the establishment processes, it was tested the high vacuum pumping, helium leak of the helium lines and hardwares mounted between the helium lines, flow controls for CL, and liquid nitrogen cool-down of possible parts (current leads, CL helium lines, and thermal shield helium lines for CLB), for the accomplishment of the required performances.

Evaluation of Microscopic Deformation Behaviors of Metal Matrix Composite due to Heat Treatment by means of SFC Test and Acoustic Emission (음향방출과 SFC 시험법에 의한 금속복합재료의 기지재 열처리 효과에 따른 미시적 변형기구 특성 평가)

  • Kang, Moon-Phil;Lee, Joon-Hyun
    • Journal of the Korean Society for Nondestructive Testing
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    • v.20 no.5
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    • pp.381-389
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    • 2000
  • Metal matrix composite(MMCs) have been rapidly becoming one of the strongest candidates for structural materials for high temperature application. It is well recognized that MMCs always experience at least one large cool-down from processing temperature before my significant applied service loading. Due to the large difference in thermal expansion coefficient between the fiber and matrix, large thermal residual stresses generally develop in composites. It was reported from many previous studies that the effects of thermal residual stress on mechanical properties and fracture behavior were much more complex and dramatic than conventional engineering materials. Therefore it is crucial to evaluate the effect of heat treatment which changes the characteristic of distribution of thermal residual stress in MMCs. Single fiber composite(SFC) test based on the balance in a micromechanical model is a quite convenient method to evaluate interfacial shear strength(IFSS) and the failure mode of composite. In this study the effect of heat treatment on IFSS and the microscopic failure mechanism of MMC is investigated by combining acoustic emission(AE) technique with SFC test. The characteristic of AE signal, IFSS and microscopic failure mechanism due to heat treatment condition is discussed.

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Effect of High-Humidity and High Temperature at Kentucky Bluegrass Growth in Summer (하절기 한지형 잔디 재배 시 침수 및 고온으로 인한 잔디의 생육 불량 현상)

  • Lee, Jeong-Ho;Choi, Jun-Yong;Lee, Song-Ho;Joo, Young-Kyoo
    • Asian Journal of Turfgrass Science
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    • v.22 no.2
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    • pp.133-140
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    • 2008
  • The growth of root and shoot normally decline dramatically in mid-summer of Korea, moreover the cool-season turfgrassgrass eventually wither to death over $30^{\circ}C$. The increase of air temperature also drives the heat of soil, that makes stress on root system. The heat stress affects physiological mechanisms of hormonal unbalance that stimulates shoot growth, photosynthesis, and transpiration. To solve those problems, many studies have been carried out to control soil moisture and OM content to decrease soil temperature for dissolving the growth retardant by heat stress. This study initiated to analyze the change of soil temperature with soil moisture, and the effect of soil depth and moisture content on heat transmit and thermal changes on turfgrass growth(productivity, green color, and damage by dryness and high temperature). Kentucky bluegrass plots prepared with 25%, 33%, 40% soil moisture treatments. Soil temperature was measured every five min. with four thermo-sensors at 12 and 2 cm soil depth. The most acceptable growth showed at 33% soil moisture, but the worst result showed at 40%. The soil moisture seriously affected on the growth of Kentucky bluegrass, however the quality of turfgrass may acceptable if we can control soil moisture down to 33% when the flooding season of monsoon.