• Title/Summary/Keyword: sensor cooling

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An Experimental Study of Injection Molding for Multi-beam Sensing Lens Using The Change of Gate Geometry (금형 게이트 크기 변화에 따른 멀티빔 센서용 렌즈 사출성형성 향상에 관한 연구)

  • Cho, S.W.;Kim, J.S.;Yoon, K.H.;Kim, J.D.
    • Transactions of Materials Processing
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    • v.20 no.5
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    • pp.333-338
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    • 2011
  • Rapidly developing IT technologies in recent years have raised the demands for high-precision optical lenses used for sensors, digital cameras, cell phones and optical storage media. Many techniques are required to manufacturing high-precision optical lenses, including multi-beam sensing lenses investigated in the current study. In the case of injection molding for thick lenses, a shrinkage phenomenon often occurs during the process. This shrinkage is known to be the main reason for the lower optical quality of the lenses. In the present work, a CAE analysis was conducted simultaneously with experiments to understand and minimize this phenomenon. In particular, the sectional area of a gate was varied in order to understand the effects of packing and cooling processes on the final shrinkage pattern. As a result of this study, it was demonstrated that a dramatic reduction of the shrinkage could be obtained by increasing the width of the gate.

An experimental study on the liquid rocket engine combustion gas cooling (액체로켓 엔진 연소가스 냉각에 관한 실험적 연구)

  • 김현중;유석진;임하영;우유철
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2003.05a
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    • pp.266-269
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    • 2003
  • During liquid rocket engine combustion, the resulting combustion gas has flow characteristics of high temperature and high velocity. An experimental study was performed to obtain basic data for a flame deflector design that is endurable under such flow characteristics. While the injected-water cools down the combustion plume, temperature and pressure of the plume was measured. As the experiment is being performed, gas temperature was measured using infrared cameras, and the gas temperature data was compared with the temperature data from the sensor in the plume. With the results of this experiment, we were able to obtain applicable temperature data for flame deflector design and predict the performance and structural strength required for installation of water injector.

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Development of X-ray Non-destructive Testing (NDT) Equipment for the Detection of Alien Substances (이물질 검출을 위한 X-Ray 비파괴검사 장비 개발)

  • Yoo, Young-Tae;Oh, Joon-Ho;Kim, Jin-Woo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.18 no.8
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    • pp.60-66
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    • 2019
  • This study aims to develop and manufacture a device for inspecting impurities in a sealed aluminum container using an X-ray technique. Two X-ray oscillators and detectors are used to detect the entire sample. The stage for sample movement was fabricated using two high-voltage generators and X-ray detectors arranged diagonally. In addition, the high-voltage generator is composed of a vacuum tube, a high-voltage generator, and circulating oil for cooling. It includes a control unit for controlling other equipment, a power supply unit, and a video output unit; the most important part of the X-ray is the X-ray generation part. In this study, a flat panel was used along with the aim of developing the detector part. In particular, the development of the scintillator introduced in this study is a primary focus. The developed scintillator can be combined with a lens and can then be assembled with a charge coupled device (CCD) sensor.

Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2013 (설비공학 분야의 최근 연구 동향 : 2013년 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.26 no.12
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    • pp.605-619
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    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. 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 fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are 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 general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, 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 is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.

Design of a SQUID Sensor Array Measuring the Tangential Field Components in Magnetocardiogram (심자도용 접선성분자장 측정방식 스퀴드 센서열 설계)

  • Kim K.;Lee Y. H;Kwon H;Kim J. M;Kim I. S;Park Y. K;Lee K. W
    • Progress in Superconductivity
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    • v.6 no.1
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    • pp.56-63
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    • 2004
  • We consider design factors for a SQUID sensor array to construct a 52-channel magnetocardiogram (MCG) system that can be used to measure tangential components of the cardiac magnetic fields. Nowadays, full-size multichannel MCG systems, which cover the whole signal area of a heart, are developed to improve the clinical analysis with high accuracy and to provide patients with comfort in the course of measurement. To design the full-size MCG system, we have to make a compromise between cost and performance. The cost is involved with the number of sensors, the number of the electronics, the size of a cooling dewar, the consumption of refrigerants for maintenance, and etc. The performance is the capability of covering the whole heart volume at once and of localizing current sources with a small error. In this study, we design the cost-effective arrangement of sensors for MCG by considering an adequate sensor interval and the confidence region of a tolerable localization error, which covers the heart. In order to fit the detector array on the cylindrical dewar economically, we removed the detectors that were located at the corners of the array square. Through simulations using the confidence region method, we verified that our design of the detector array was good enough to obtain whole information from the heart at a time. A result of the simulation also suggested that tangential-component MCG measurement could localize deeper current dipoles than normal-component MCG measurement with the same confidence volume; therefore, we conclude that measurement of the tangential component is more suitable to an MCG system than measurement of the normal component.

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Thermal Conductivity Effect of Heat Storage Layer using Porous Feldspar Powder (다공질 장석으로 제조한 축열층의 열전도 특성)

  • Kim, Sung-Wook;Go, Daehong;Choi, Eun-Kyeong;Kim, Sung-Hwan;Kim, Tae-Hyoung;Lee, Kyu-Hwan;Cho, Jinwoo
    • Economic and Environmental Geology
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    • v.50 no.2
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    • pp.159-170
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    • 2017
  • The temporal and spatial temperature distribution of the heat storage mortar made of porous feldspar was measured and the thermal properties and electricity consumption were analyzed. For the experiment, two real size chambers (control model and test model) with hot water pipes were constructed. Two large scale models with hot water pipes were constructed. The surface temperature change of the heat storage layer was remotely monitored during the heating and cooling process using infrared thermal imaging camera and temperature sensor. The temperature increased from $20^{\circ}C$ to $30^{\circ}C$ under the heating condition. The temperature of the heat storage layer of the test model was $2.0-3.5^{\circ}C$ higher than the control model and the time to reach the target temperature was shortened. As the distance from the hot water pipe increased, the temperature gap increased from $4.0^{\circ}C$ to $4.8^{\circ}C$. The power consumed until the surface temperature of the heat storage layer reached $30^{\circ}C$ was 2.2 times that of the control model. From the heating experiment, the stepwise temperature and electricity consumption were calculated, and the electricity consumption of the heat storage layer of the test model was reduced by 66%. In the cooling experiment, the surface temperature of the heat storage layer of the test model was maintained $2^{\circ}C$ higher than that of the control model. The heat storage effect of the porous feldspar mortar was confirmed by the temperature experiment. With considering that the time to reheat the heat storage layer is extended, the energy efficiency will be increased.

Air-conditioning and Heating Time Prediction Based on Artificial Neural Network and Its Application in IoT System (냉난방 시간을 예측하는 인공신경망의 구축 및 IoT 시스템에서의 활용)

  • Kim, Jun-soo;Lee, Ju-ik;Kim, Dongho
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2018.05a
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    • pp.347-350
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    • 2018
  • In order for an IoT system to automatically make the house temperature pleasant for the user, the system needs to predict the optimal start-up time of air-conditioner or heater to get to the temperature that the user has set. Predicting the optimal start-up time is important because it prevents extra fee from the unnecessary operation of the air-conditioner and heater. This paper introduces an ANN(Artificial Neural Network) and an IoT system that predicts the cooling and heating time in households using air-conditioner and heater. Many variables such as house structure, house size, and external weather condition affect the cooling and heating. Out of the many variables, measurable variables such as house temperature, house humidity, outdoor temperature, outdoor humidity, wind speed, wind direction, and wind chill was used to create training data for constructing the model. After constructing the ANN model, an IoT system that uses the model was developed. The IoT system comprises of a main system powered by Raspberry Pi 3 and a mobile application powered by Android. The mobile's GPS sensor and an developed feature used to predict user's return.

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Development of New Ocean Radiation Automatic Monitoring System (새로운 해양 방사선 자동 감시 시스템의 개발)

  • Kim, Jae-Heong;Lee, Joo-Hyun;Lee, Seung-Ho
    • Journal of IKEEE
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    • v.23 no.2
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    • pp.743-746
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    • 2019
  • In this paper we proposed a new ocean radiation automatic monitoring system. The proposed system has the following characteristics: First, using NaI + PVT mixed detectors, the response speed is fast and precision analysis is possible. Second, the application of temperature compensation algorithm to scintillator-type sensors does not require additional cooling devices and enables stable operation in the changing ocean environment. Third, since cooling system is not needed, electricity consumption is low, and electricity can be supplied reliably by utilizing solar energy, which can be installed at the observation deck of ocean environment. Fourth, using GPS and wireless communications, accurate location information and real-time data transmission function for measurement areas enables immediate warning response in the event of nuclear accidents such as those involving neighboring countries. The results tested by the authorized testing agency to assess the performance of the proposed system were measured in the range of $5{\mu}Sv/h$ to 15mSv/h, which is the highest level in the world, and the accuracy was determined to be ${\pm}8.1%$, making normal operation below the international standard ${\pm}15%$. The internal environmental grade (waterproof) was achieved, and the rate of variation was measured within 5% at operating temperature of $-20^{\circ}C$ to $50^{\circ}C$ and stability was verified. Since the measured value change rate was measured within 10% after the vibration test, it was confirmed that there will be no change in the measured value due to vibration in the ocean environment caused by waves.

Remote Multi-control Smart Farm with Deep Learning Growth Diagnosis Function

  • Kim, Mi-jin;Kim, Ji-ho;Lee, Dong-hyeon;Han, Jung-hoon
    • Journal of the Korea Society of Computer and Information
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    • v.27 no.9
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    • pp.49-57
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    • 2022
  • Currently, the problem of food shortage is emerging in our society due to climate problems and an increase population in the world. As a solution to this problem, we propose a multi-remote control smart farm that combines artificial intelligence (AI) and information and communication technology (ICT) technologies. The proposed smart farm integrates ICT technology to remotely control and manage crops without restrictions in space and time, and to multi-control the growing environment of crops. In addition, using Arduino and deep-learning technology, a smart farm capable of multiple control through a smart-phone application (APP) was proposed, and Ai technology with various data securing and diagnosis functions while observing crop growth in real-time was included. Various sensors in the smart farm are controlled by using the Arduino, and the data values of the sensors are stored in the built database, so that the user can check the stored data with the APP. For multiple control for multiple crops, each LED, COOLING FAN, and WATER PUMP for two or more growing environments were applied so that the user could control it conveniently. And by implementing an APP that diagnoses the growth stage through the Tensor-Flow framework using deep-learning technology, we developed an application that helps users to easily diagnose the growth status of the current crop.

Active-Sensing Based Damage Monitoring of Airplane Wings Under Low-Temperature and Continuous Loading Condition (능동센서 배열을 이용한 저온 반복하중 환경 항공기 날개 구조물의 손상 탐지)

  • Jeon, Jun Young;Jung, Hwee kwon;Park, Gyuhae;Ha, Jaeseok;Park, Chan-Yik
    • Journal of the Korean Society for Nondestructive Testing
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    • v.36 no.5
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    • pp.345-352
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    • 2016
  • As aircrafts are being operated at high altitude, wing structures experience various fatigue loadings under cryogenic environments. As a result, fatigue damage such as a crack could be develop that could eventually lead to a catastrophic failure. For this reason, fatigue damage monitoring is an important process to ensure efficient maintenance and safety of structures. To implement damage detection in real-world flight environments, a special cooling chamber was built. Inside the chamber, the temperature was maintained at the cryogenic temperature, and harmonic fatigue loading was given to a wing structure. In this study, piezoelectric active-sensing based guided waves were used to detect the fatigue damage. In particular, a beamforming technique was applied to efficiently measure the scattering wave caused by the fatigue damage. The system was used for detection, growth monitoring, and localization of a fatigue crack. In addition, a sensor diagnostic process was also applied to ensure the proper operation of piezoelectric sensors. Several experiments were implemented and the results of the experiments demonstrated that this process could efficiently detect damage in such an extreme environment.