• Title/Summary/Keyword: Flow and temperature changes

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Changes of Facial Temperature and Blood Flow Rates by Treatment of Miso Facial Rejuvenation Acupuncture (미소안면침이 안면 피부 온도와 혈류량에 미치는 영향)

  • Kim, Tae Yeon;Bak, Jong Phil;Kim, Yong Min
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.27 no.4
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    • pp.481-486
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    • 2013
  • To investigate the effects of facial temperature and blood flow rates generated by Miso Facial Rejuvenation Acupuncture treatment. Ten women in their twenties to fifties with no skin diseases were recruited. Miso Facial Rejuvenation Acupuncture(MFRA) was performed on the both sides of their face. We measured their facial temperature using Digital Infrared Thermal Imaging(DITI) and blood flow rates using Laser Doppler Perfusion Imaging(LDPI) at pre-treatment, immediately, twenty and sixty minutes after treatment. We analyzed data using student's t-test(p<0.05). After MFRA treatment, facial temperature on the measurement area increased immediately from $30.5{\pm}1.0^{\circ}C$ to $31.5{\pm}1.0^{\circ}C$, a statistically significant increase. Sixty minutes after treatment, facial temperature on the measurement area decreased a little bit($30.2{\pm}0.6^{\circ}C$), but there was no statistical significance. After MFRA treatment, facial blood flow rates on the measurement area increased immediately from $165.1{\pm}52.3$ PU to $342.7{\pm}51.3$ PU, a statistically significant increase. Sixty minutes after treatment, facial blood flow rates measurement area were recovered almost at the same level as before treatment. MFRA treatment could increase facial temperature and blood flow rates.

TEMPERATURE CHANGES IN THE PULP ACCORDING TO VARIOUS ESTHETIC RESTORATIVE MATERIALS AND BASES DURING CURING PROCEDURE (광중합 시 수종의 심미적 수복재와 이장재의 사용에 따른 치수내 온도변화)

  • 장혜란;이형일;이광원;이세준
    • Restorative Dentistry and Endodontics
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    • v.26 no.5
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    • pp.393-398
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    • 2001
  • Polymerization of light-activated restorations results in temperature increase caused by both the exothermic reaction process and the energy absorbed during irradiation. Within composite resin, temperature increases up to 2$0^{\circ}C$ or more during polymerization. But, insulation of hard tissue of tooth lowers this temperature increase in pulp. However, many clinicians are concerned about intrapulpal temperature injury. The purpose of this study was to evaluate temperature changes in the pulp according to various restorative materials and bases during curing procedure. Caries and restoration-free mandibular molars extracted within three months were prepared Class I cavity of 3$\times$6mm with high speed handpiece fissure bur. 1mm depth of dentin was evaluated with micrometer in mesial and distal pulp horns. Pulp chambers were filled with 37.0$\pm$0.1$^{\circ}C$ water to CEJ. Chromium-alumina thermocouple was placed in pulp horn below restorative materials for evaluating of temperature changes. This thermocouple was connected to temperature-recording device(Multiplication analyzer MX, 6.000, JAPAN). Temperature changes was evaluated from initial 37.$0^{\circ}C$ after temperature changes to 37.$0^{\circ}C$. Tip of curing unit was placed in the center of prepared cavity separated 1mm from restorative materials. Curing time was 40s. The restorative materials were used with Z 100, Fuji II LC, Compoglass flow and bases were used with Vitrebond, Dycal. Resrorative materials were placed in 2mm. The depth of bases were formed in 1mm and in this upper portion, resin of 2mm depth was placed. This procedure was performed 10 times. The results were as follows. 1. All the groups showed that the temperature in pulp increased as curing time increased 2. The temperature increase of glass ionomer was significantly higher than that of Resin and Compomer during curing procedure (P<0.05). 3. The temperature increase in glass ionomer base was significantly higher than that of Calcium hydroxide base during Resin curing procedure (P<0.05).

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Effects of the secondary flow on the turbulent heat transfer of a flat plate wake (2차유동이 평판후류의 난류열전달에 미치는 영향)

  • Kim, Hyeong-Su;Lee, Jun-Sik;Gang, Sin-Hyeong
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.22 no.4
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    • pp.417-427
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    • 1998
  • The effect of secondary flow on the heat transfer of a turbulent wake generated by a flat plate was experimentally investigated. The secondary flow was induced in a curved duct in which the flat plate wake generator was installed. All three components of turbulent heat flux were measured in the plane containing the mean radius of curvature of the curved duct. The results showed that mean temperature profiles deviate from the similarity of the straight wake because of the cold fluid transported from the free-stream. The half-width of the mean temperature profile increased rapidly by upwash motion of the secondary flow. The changes to turbulence structure caused by the secondary flow show more pronounced effect on heat transport than on momentum transport. This is because the response to the variation of flow conditions is delayed in temperature field. Negative production of the turbulent heat flux is observed in the inner wake region. From the conditional averaging, it has been found that the negative production of the turbulent heat flux is generated due to a mixing process between the hot and low momentum eddies occupied in the inner wake region and the cold and high momentum eddies in the potential region.

Analysis on Characteristics of Thermal Flow of Hot Air in Single Shell of Shell and Tube-type Heat Exchanger (쉘앤튜브형 열교환기의 단일 쉘 내 고온공기 열유동 특성 해석)

  • Young-Joon Yang
    • Journal of the Korean Society of Industry Convergence
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    • v.26 no.2_2
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    • pp.255-263
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    • 2023
  • The shell and tube-type heat exchangers have been frequently used in many industrial field because of its simple structure and wide operation conditions and so on. The purpose of this study is to investigate the flow characteristics in single shell of shell and tube-type heat exchanger according to velocity and temperature of hot air released from heat exchanger simulator through numerical analysis. As the results, the temperature was decreased in almost quadratic curve from top to bottom in single shell of the shell and tube-type heat exchanger. Further the changes of pressure and velocity in outlet according to change of inlet temperature were not observed. The cost for operating the shell and tube-type heat exchanger should be compared the supply cost of hot air with that of velocity in order to make a economic decision.

Effects of critical viscosity temperature and flux feeding ratio on the slag flow behavior on the wall of a coal gasifier (석탄 가스화시 회분의 임계점도온도 및 플럭스 비율 변화에 따른 벽면 슬래그 거동 특성 분석)

  • Ye, Insoo;Ryu, Changkook;Kim, Bongkeun
    • 한국연소학회:학술대회논문집
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    • 2014.11a
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    • pp.21-24
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    • 2014
  • In the entrained-flow coal gasifier, coal ash turns into a molten slag most of which deposits onto the wall to form liquid and solid layers. Critical viscosity refers to the viscosity at the interface of the two layers. The slag layers play an important role in protecting the wall from physical/chemical attack from the hot syngas and in continuously discharging the ash to the slag tap at the bottom of the gasifier. For coal with high ash melting point and slag viscosity, CaO-based flux is added to coal to lower the viscosity. This study evaulates the effect of critical viscosity temperature and ash/flux ratio on the slag behavior using numerical modelling in a commercial gasifier. The changes in the slag layer thickness, heat transfer rate, surface temperature and velocity profiles were analyzed to understand the underlying mechanism of slag flow and heat transfer.

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Study on Thermal Insulation Design and Heat Flow Analysis of Spacecraft Shipping Container (위성 운송용 컨테이너의 단열 설계와 열 유동 해석에 관한 연구)

  • Park, Sang-Rae;Lee, Choon-Woo;Kim, Jin-Taek
    • Journal of Aerospace System Engineering
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    • v.14 no.1
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    • pp.8-15
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    • 2020
  • In this paper, we propose a container wall and its boundary layer insulation design method that can maintain the temperature inside the spacecraft shipping container constantly under the condition that the heat or the external temperature changes severely to safely transport the satellite to the launch site. We will examine if the temperature inside the satellite shipping container is kept constant through the heat flow analysis and the satellite heat transfer analysis for the external environment of the satellite shipping container. Through the flow analysis inside the container, the flow distribution around the satellite in the container is analyzed, and the auxiliary fan, air conditioning system and special grill guide structure design for improving and optimizing heat flow performance are proposed.

A Study on Constitutive Equations for Warm and Hot Forging (온, 열간 단조의 구성방정식에 관한 연구)

  • 강종훈;박인우;제진수;강성수
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.9
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    • pp.75-81
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    • 1998
  • Simulations of warm and hot forming processes need reliable expressions of flow stress at high temperatures. To get flow stress of the materials usually tension, compression and torsion tests are conducted. In this study, hot compression tests were adopted to get flow stress of medium carbon steel. Experiments have been conducted under both isothermal, near constant strain rate in the temperature ranges 650~100$0^{\circ}C$. Phase transformation takes place by temperature changes for steels in hot and warm forging stage. So Constitutive equation are formulated as the function of strain, strain rate and temperature for isothermal conditions and phase transformation.

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A Study on Body Temperature Measurement of Woven Textile Electrode Using Lock-In-Amp based on Microprocessor (마이크로 프로세서 기반 Lock-In-Amp를 이용한 텍스타일 직물전극의 체온 측정에 관한 연구)

  • Lee, Kang-Hwi;Lee, Sung-Su;Lee, Jeong-Whan;Song, Ha-Young
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.7
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    • pp.1141-1148
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    • 2017
  • Generally, a thermistor made by sintering a metal oxide is widely used to measure the ambient temperature. This thermistor is widely used not only for industrial use but also for medical use because of its excellent sensitivity, durability, temperature change characteristics and low cost. In particular, the normal body temperature is 36.9 degrees relative to the armpit temperature, and it is most closely related to the circulating blood flow. Previous studies have shown that body temperature changes during biomechanical changes and body temperature changes by anomalous signs or illnesses. Therefore, in this study, we propose a Lock-In-Amp design to detect minute temperature changes of clothing and thermistor wired by a preacher as a method to regularly measure body temperature in daily life. Especially, it is designed to measure the minute resistance change of the thermistor according to body temperature change even in a low-cost microprocessor environment by using a micro-processor-based Lock-In-Amp, and a jacquard and the thermistor is arranged so as to be close to the side, so that the reference body temperature can be easily measured. The temperature was measured and stored in real time using short-range wireless communication for non - restraint temperature monitoring. A baby vest was made to verify its performance through temperature experiments for infants. The measurement of infant body temperature through the existing skin sensor or thermometer has limitations in monitoring infant body temperature for a long time without restriction. However, it can be overcome by using the embroidery fabric based micro temperature monitoring wireless monitoring device proposed in this study.

Study on Ti Deposition Rate from $TiI_4$ on Stainless Steel ($TiI_4$에 의한 Stainless 강의 Ti증착속도에 관한 연구)

  • Yoo, Jae-Keun;Han, Jun-Su;Paik, Young-Hyun
    • Journal of the Korean institute of surface engineering
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    • v.18 no.1
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    • pp.5-11
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    • 1985
  • Titanium was deposited onto AISI-430 stainless steel by chemical vapor deposition from $TiI_4\;and\;H_2$ gas mixture. Effects of temperature, flow rate of the gas, and $TiI_4$ partial pressure on the deposition rate were thoroughly investigated. The deposition rate of Ti was found to be constant at the given temperature and was increased with increasing temperature. The rate is controlled by surface reaction at the flow rate of gas higher than 500 ml/min, whereas at the flow rate lower than that by diffusional process. It is also interesting to note that the reaction mechanism changes at 1050$^{\circ}C$, at temperatures lower than 1050$^{\circ}C$ the activation energy is 56.9 Kcal/mol, whilst at temperatures higher than that is 8.3 Kcal/mol.

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Effect of Temperature and Reactants Flow Rate on the Synthesis Gas Production in a Fixed Bed Reactor (고정층 반응기에서 합성가스 생성에 미치는 반응온도와 반응물 유속의 영향)

  • Kim, Sang-Bum;Kim, Young-Kook;Hwang, Jae-Young;Kim, Myung-Soo;Hahm, Hyun-Sik
    • Journal of the Korean Applied Science and Technology
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    • v.21 no.1
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    • pp.45-50
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    • 2004
  • The effects of reaction temperature and flow rate of reactants on the methane conversion, product selectivity, product ratio, and carbon deposition were investigated with 13wt% Ni/MgO catalyst. Reaction temperatures were changed from 600 to $850^{\circ}C$, and reactants flow rates were changed from 100 to 200 mL/mim. There were no significant changes in the methane conversion observed in the range of temperatures used. It is possibly stemmed from the nearly total exhaustion of oxygen introduced. The selectiveties of hydrogen and carbon monoxide did not largely depend on the reaction temperature. The selectivities of hydrogen and carbon monoxide were 96 and 90%, respectively. Carbon deposition observed was the smallest at $750^{\circ}C$ and the largest at $850^{\circ}C$. It is found that the proper reaction temperature is $750^{\circ}C$. The best reactant flow rate was 150 ml/min.