• Title/Summary/Keyword: Thermal Control Unit

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Suggestion of Logic to Control Power Plant Equipped ESS in case of Full Open Turbine Control Valve (ESS를 이용한 발전소 터빈제어밸브 전개 운전 제어로직 제안)

  • In Young Chung;Jae-Heon Lee
    • Plant Journal
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    • v.18 no.4
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    • pp.66-72
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    • 2023
  • In order to respond to the demand for flexible operation of thermal power generation, development of natural sliding pressure operation that minimizes throttle loss by opening the turbine control valve 100% and maximize power generation efficiency in conjunction with ESS in order to quickly respond to fluctuations in the system frequency is required. The logic development of natural sliding pressure operation with ESS was developed to modify the existing logic at the power plant's top-level control logic such as the unit master, the boiler master and the turbine master. Cooperative control algorithms that complement the advantages and disadvantages of ESS operation (quick response, limited capacity) and power plant operation (slow response, continuous operation) not only improve efficiency when applied to actual power plants, but also respond quickly and flexibly to load demands to ensure system stability.

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Influences of Wearing Far-infrared Indoor Clothing on Skin Blood Flow, Perceptual and Thermal Responses (원적외선 방사 기능 실내복 착용이 인체 피부혈류량, 온열 심리 및 온열 생리 기능에 미치는 영향)

  • Baek, Yoon Jeong;Seo, Wonji;Kim, Hyung Chan;Lee, Joo-Young
    • Journal of the Korean Society of Clothing and Textiles
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    • v.44 no.2
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    • pp.342-353
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    • 2020
  • The purpose of this study was to evaluate far-infrared clothing (FIR condition) with non-far-infrared clothing (Control condition) to assess the effects of FIR on thermo-physiological responses. Eight young healthy males (23.0±2.3 yr, 176.5±3.7 cm, and 69.0±4.3 kg) participated in this experimental trial, which consisted of a 20 min rest followed by a 40 min walk (4.0 km·hr-1) and a 20 min recovery at 20℃ with 50%RH. The results showed that finger skin blood flow and mean skin temperature were significantly higher for the FIR condition than the control during exercise and recovery (p<.001). Clothing microclimate temperature of the FIR condition was 0.5℃ higher on the back (p=.001) and 0.4℃ higher on the thigh (p=.015) during recovery. Clothing microclimate relative humidity of the FIR condition was 13% higher on the chest (p=.006) and 19% higher on the back (p<.001) during exercise than control. Subjects felt warmer and more comfortable in the FIR condition than in the control (p<.05). Perceived skin wettedness (%BSA) was less in the FIR condition than in the control (p=.001). These results indicate that ceramic-embedded clothing had significant effects on thermoregulatory responses for light activity in an indoor environment.

Development of Embedded Board for Integrated Radiation Exposure Protection Fireman's Life-saving Alarm (일체형 방사선 피폭 방호 소방관 인명구조 경보기의 임베디드 보드 개발)

  • Lee, Young-Ji;Lee, Joo-Hyun;Lee, Seung-Ho
    • Journal of IKEEE
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    • v.23 no.4
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    • pp.1461-1464
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    • 2019
  • In this paper, we propose the development of embedded board for integrated radiation exposure protection fireman's life-saving alarm capable of location tracking and radiation measurement. The proposed techniques consist of signal processing unit, communication unit, power unit, main control unit. Signal processing units apply shielding design, noise reduction technology and electromagnetic wave subtraction technology. The communication unit is designed to communicate using the wifi method. In the main control unit, power consumption is reduced to a minimum, and a high performance system is formed through small, high density and low heat generation. The proposed techniques are equipment operated by exposure to poor conditions, such as disaster and fire sites, so they are designed and manufactured for external appearance considering waterproof and thermal endurance. The proposed techniques were tested by an authorized testing agency to determine the effectiveness of embedded board. The waterproof grade has achieved the IP67 rating, which can maintain stable performance even when flooded with water at the disaster site due to the nature of the fireman's equipment. The operating temperature was measured in the range of -10℃ to 50℃ to cope with a wide range of environmental changes at the disaster site. The battery life was measured to be available 144 hours after a single charge to cope with emergency disasters such as a collapse accident. The maximum communication distance, including the PCB, was measured to operate at 54.2 meters, a range wider than the existing 50 meters, at a straight line with the command-and-control vehicle in the event of a disaster. Therefore, the effectiveness of embedded board for embedded board for integrated radiation exposure protection fireman's life-saving alarm has been demonstrated.

A study on the burn-in test to accomplish high quality cockpit air of an ultra-sonic aircraft in the early stage of production (생산 초기 초음속 항공기 조종석의 고품질 공기 확보를 위한 burn-in test 연구)

  • Shin, Jae Hyuk;Park, Sung Jae;Seo, Dong Yeon;Jeong, Suheon
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.44 no.10
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    • pp.871-876
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    • 2016
  • Abnormal odor similar with burning smell often appears at the cockpit in the beginning of ultra-sonic aircraft without air filter due to the heating of production materials remained at the bleed air duct. Sources of the odor should be removed by burn-in test before test flight in order to prevent pilot confuses order with emergency such as fire of engine. However, the present method cannot prevent abnormal odor completely at the high altitude flight because maximum temperature of flight is higher than it of burn-in-test. This paper suggests burn-in test improved based on the analysis of thermal conditions of high altitude flight. It is verified that the existing burn-in test cannot cover thermal conditions of high altitude flight due to the discontinuous flow control, high change rate of temperature per unit time and difference between limit temperature of condenser and turbine. In order to overcome the limitations of current methods, the new burn-in test with continuous flow control are suggested. The continuous flow control are achieved by ram air inlet control. The effect of suggested method are verified by ground tests and flight tests. The results show the bleed air temperature can cover the temperature of high altitude flight and prevent abnormal odor at the flight test.

Recent Progress in Air-Conditioning and Refrigeration Research: A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2014 (설비공학 분야의 최근 연구 동향: 2014년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.7
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    • pp.380-394
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    • 2015
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2014. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of heat and mass transfer, cooling and heating, and air-conditioning, the flow inside building rooms, and smoke control on fire. Research issues dealing with duct and pipe were reduced, but flows inside building rooms, and smoke controls were newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for thermal contact resistance measurement of metal interface, a fan coil with an oval-type heat exchanger, fouling characteristics of plate heat exchangers, effect of rib pitch in a two wall divergent channel, semi-empirical analysis in vertical mesoscale tubes, an integrated drying machine, microscale surface wrinkles, brazed plate heat exchangers, numerical analysis in printed circuit heat exchanger. In the area of pool boiling and condensing, non-uniform air flow, PCM applied thermal storage wall system, a new wavy cylindrical shape capsule, and HFC32/HFC152a mixtures on enhanced tubes, were actively studied. In the area of industrial heat exchangers, researches on solar water storage tank, effective design on the inserting part of refrigerator door gasket, impact of different boundary conditions in generating g-function, various construction of SCW type ground heat exchanger and a heat pump for closed cooling water heat recovery were performed. (3) In the field of refrigeration, various studies were carried out in the categories of refrigeration cycle, alternative refrigeration and modelling and controls including energy recoveries from industrial boilers and vehicles, improvement of dehumidification systems, novel defrost systems, fault diagnosis and optimum controls for heat pump systems. It is particularly notable that a substantial number of studies were dedicated for the development of air-conditioning and power recovery systems for electric vehicles in this year. (4) In building mechanical system research fields, seventeen studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, and renewable energies, piping in the buildings. Proposed designs, performance performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the evaluation of work noise in tunnel construction and the simulation and development of a light-shelf system. The subjects of building energy were worked on the energy saving of office building applied with window blind and phase change material(PCM), a method of existing building energy simulation using energy audit data, the estimation of thermal consumption unit of apartment building and its case studies, dynamic window performance, a writing method of energy consumption report and energy estimation of apartment building using district heating system. The remained studies were related to the improvement of architectural engineering education system for plant engineering industry, estimating cooling and heating degree days for variable base temperature, a prediction method of underground temperature, the comfort control algorithm of car air conditioner, the smoke control performance evaluation of high-rise building, evaluation of thermal energy systems of bio safety laboratory and a development of measuring device of solar heat gain coefficient of fenestration system.

Effects of the electronic expansion valve and variable velocity compressor on the performance of a refrigeration system

  • Lago, Taynara G.S.;Ismail, Kamal A.R.;Nobrega, Claudia R.E.S.;Moura, Luiz F.M.
    • Advances in Energy Research
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    • v.7 no.1
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    • pp.1-19
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    • 2020
  • Energy consumption of air-conditioning and refrigeration systems is responsible for about 25 to 30% of the energy demand especially in hot seasons. This equipment is mostly electricity dependent and their use in principle affects negatively the environment. Enhancing the energy efficiency of the existing equipment is important as one of the measures to reduce environment impacts. This paper reports the results of an experimental study to evaluate the impacts of the use electronic expansion valve and variable velocity compressor on the performance of vapor compression refrigeration system. The experimental rig is composed of two independent circuits one for the vapor compression system and the other is the secondary fluid system. The vapor compression system is composed of a forced air condenser unit, evaporator, hermetic compressor and expansion elements, while the secondary system has a pump for circulating the secondary fluid, and an air conditioning heat exchanger. The manufacturer's data was used to determine the optimal points of operation of the system and consequently tests were done to evaluate the influence of variation of the compressor velocity and the opening of the expansion device on the performance of the refrigeration system. A fuzzy logic model was developed to control the rotational velocity of the compressor and the thermal load. Fuzzy control model was made in LabVIEW software with the objective of improving the system performance, stability and energy saving. The results showed that the use of fuzzy logic as a form of control strategy resulted in a better energy efficiency.

Berberine Alleviates Paclitaxel-Induced Neuropathy

  • Rezaee, Ramin;Monemi, Alireza;SadeghiBonjar, Mohammad Amin;Hashemzaei, Mahmoud
    • Journal of Pharmacopuncture
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    • v.22 no.2
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    • pp.90-94
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    • 2019
  • Objectives: Paclitaxel (PTX) as an anticancer drug used against solid cancers, possesses adverse reactions such as neuropathic pain which has confined its use. PTX-induced neuropathic pain is mediated via activation of oxidative stress. Berberine (BER), an isoquinoline phytochemical found in several plants, exerts strong antioxidant and painkilling properties. In the current study, we aimed to evaluate pain-relieving effect of BER in a mouse model of PTX-induced neuropathic pain. Methods: This study was done using 42 male albino mice that were randomly divided into 6 groups (n = 7) as follow: Sham-operated (not treated with PTX), negative control group (PTX-treated mice receiving normal saline), BER 5, 10, and 20 mg/kg (PTX-treated mice receiving BER) and positive control group (PTX-treated mice receiving imipramine 10 mg/kg). Neuropathic pain was induced by intraperitoneal administration of four doses of PTX (2 mg/kg/day) on days 1, 3, 5 and 7. Then, on day 7, hot plate test was done to assess latency to heat to measure possible anti-neuropathic pain effect of BER. Results: Four doses of PTX 2 mg/kg/day induced neuropathy that was reduced by BER at all time-points (i.e. 0, 30, 60, 90 and 120 min) after injection (P < 0.001 in comparison to control). The statistical analysis of data showed significant differences between groups (P < 0.001 in comparison to negative control), at 30, 60, 90 and 120 min after injection of BER 5, 10 and 20 mg/kg; in other words, 30, 60, 90 and 120 min after BER administration, neuropathic pain was significantly reduced as compared to normal saline-treated mice. Conclusion: Altogether, our results showed that PTX could induce neuropathic pain as reflected by hyperalgesia and BER could alleviate PTX-induced thermal hyperalgesia.

An Empirical Study on the Quality Reliability of the Start-up performance of the Fixed Wing Aircraft at low temperature (고정익 항공기 저온 시동 성능의 품질 신뢰성 향상에 관한 실증적 연구)

  • Kim, DW;Jeong, SH
    • Journal of Korean Society for Quality Management
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    • v.46 no.1
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    • pp.169-188
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    • 2018
  • Purpose: The purpose of this study is to analyze low-temperature starting performance of the light attacker and to search and improve the aircraft system including battery and Battery Charge and Control Unit(BCCU). Methods: In order to improve the starting up performance of the light attacker at low-temp, various deficiency cause were derived and analyzed using Fault Tree Analysis method. As a result, it was confirmed there were drawbacks in the charging and discharging mechanism of the battery. The inactivation of the battery's electrolyte at low-temp and the premature termination of the battery charge were the main cause. After long error and trial, we improved these problems by improving performance of battery and optimizing the charging algorithm of BCCU. Results: It was confirmed that the problems of starting up failures were solved through the combined performance test of the battery and BCCU, the ground test using the aircraft system and the operation test conducted by Korea Airforce operating unit for 3 months in winter. Conclusion: This study showed that the improvement of quality reliability was achieved and thus the start-up performance issue of the light attacker has been resolved at low temperature. And it is expected that the design methodologies of temperature-affected electrical system of aircraft will contribute to the development of the aircraft industry in the future.

Validation of sequence test method of Pb-free solder joint for automotive electronics (자동차 전장품용 무연솔더 접합부의 시리즈 시험 유효성)

  • Kim, A Young;Oh, Chul Min;Hong, Won Sik
    • Journal of Welding and Joining
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    • v.33 no.3
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    • pp.25-31
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    • 2015
  • Due to environmental regulations (RoHS, WEEE and ELV) of the European Union, electronics and automotive electronics have to eliminate toxic substance from electronic devices and system. Specifically, reliability issue of lead-free solder joint have an increasing demand for the car electronics caused by ELV banning. The authors prepared engine control unit and cabin electronics soldered with Sn-3.0Ag-0.5Cu (SAC305). To compare with the degradation characteristics of solder joint strength, thermal cycling test (TC), power-thermal cycling test (PTC) and series tests were conducted. Series tests were conducted for TC and PTC combined stress test using the same sample in sequence and continuously. TC test was performed at $-40{\sim}125^{\circ}C$ and soak time 10 min for 1000 cycles. PTC test was applied by pulse power and full function conditions during 100 cycles. Combined stress test was tested in accordance with automotive company standard. Solder joint degradation was observed by optical microscopy and environment scanning electron microscopy (ESEM). In addition, to compare with deterioration of bond strength of quad flat package (QFP) and chip components, we have measured lead pull and shear strength. Based on the series test results, consequently, we have validated of series test method for lifetime and reliability of Pb-free solder joint in automotive electronics.

Energy Consumption in Mushroom Canning Factory (양송이통조림 가공중의 에너지소비량 조사연구)

  • Lee, Dong-Sun;Park, Know-Hyun;Shin, Hyu-Nyun;Shin, Dong-Hwa
    • Korean Journal of Food Science and Technology
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    • v.13 no.4
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    • pp.328-333
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    • 1981
  • As a step to investigate energy conservation in canneries, energy consumption pattern and energy usages of various unit operations in a mushroom cannery were examined. The results are as follows; 1. In the mushroom cannery, fuel oil and electricity were used mainly for temperature control of mushroom growing house in winter and various cultivation operation respectively. To grow and process 1 kg of mushroom, thermal energy of 4634 kcal and electrical energy of 0. 116 kwh were consumed. About 80% of all energy was consumed for cultivation. 2. Steam qualities at each respective processing line were $92{\sim}94%$, giving no great differences among lines. 3. As a direct energy in 1 day processing operations of 8 tons of mushroom, thermal energy of $301.5{\times}10^{4}kcal$ and electrical energy of 60.1 kwh were used. The energy intensive operations were blanching (35%) and retorting (38%).

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