• Title/Summary/Keyword: Temperature control unit

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Relationship between Urban Environment and Local Temperature for Managing Urban Heat Island Effect in Neighborhood (근린단위의 도시열섬관리를 위한 국지온도와 도시환경의 관계)

  • Lee, Gunwon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.10
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    • pp.806-816
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    • 2017
  • This study aims to offer effective policies for managing local temperatures and reducing the heat island effect by identifying elements that affect local temperatures. The three elements of natural environment, land use, and land coverage were first selected, and then control factors were applied, including season, weather, and measurement units for wind speed. In order to analyze these factors' relations to summer temperatures, an integrated model was developed, and an analysis was conducted of the urban heat island reduction effect of elements impacting local temperatures. The analysis used nationwide weather system (AWS) data from July and August 2007 and 2011-2016, land coverage data provided by the Ministry of Environment, and land use area data from local governments after rearranging them based upon their falling within a 500-meter radius ($0.79km^2$) of AWS measuring points. The study results show that the natural environment, land use, and land coverage all have a relation to changes in local temperatures. Natural elements have the greatest impact, and land use has the lowest. The results could provide basic data for establishing more effective policies to mitigate the heat island effect and strategies for enhancing the sustainability of cities.

Effects of low NaNO2 and NaCl concentrations on Listeria monocytogenes growth in emulsion-type sausage

  • Lee, Jeeyeon;Gwak, Eunji;Lee, Heeyoung;Ha, Jimyeong;Lee, Soomin;Kim, Sejeong;Oh, Mi-Hwa;Park, Beom-Young;Choi, Kyoung-Hee;Yoon, Yohan
    • Asian-Australasian Journal of Animal Sciences
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    • v.30 no.3
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    • pp.432-438
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    • 2017
  • Objective: The objective of this study was to evaluate the effect of combinations of $NaNO_2$ and NaCl concentrations on Listeria monocytogenes (L. monocytogenes) growth in emulsion-type sausage. Methods: Emulsion-type sausages formulated with different combinations of $NaNO_2$ (0 and 10 ppm) and NaCl (1.00%, 1.25%, and 1.50%) were inoculated with a five-strain L. monocytogenes mixture, and stored at $4^{\circ}C$, $10^{\circ}C$, and $15^{\circ}C$, under aerobic or vacuum conditions. L. monocytogenes cell counts were measured at appropriate intervals, and kinetic parameters such as growth rate and lag phase duration (LPD) were calculated using the modified Gompertz model. Results: Growth rates increased (0.004 to 0.079 Log colony-forming unit [CFU]/g/h) as storage temperature increased, but LPD decreased (445.11 to 8.35 h) as storage temperature and NaCl concentration increased. The effect of combinations of NaCl and low-$NaNO_2$ on L. monocytogenes growth was not observed at $4^{\circ}C$ and $10^{\circ}C$, but it was observed at $15^{\circ}C$, regardless of atmospheric conditions. Conclusion: These results indicate that low concentrations of $NaNO_2$ and NaCl in emulsion-type sausage may not be sufficient to prevent L. monocytogenes growth, regardless of whether they are vacuum-packaged and stored at low temperatures. Therefore, additional techniques are necessary for L. monocytogenes control in the product.

Comparison of Phytoncide (monoterpene) Concentration by Type of Recreational Forest (산림휴양지 유형에 따른 피톤치드(모노테르펜) 농도 비교)

  • Lee, Yong-Ki;Woo, Jung-Sik;Choi, Si-Rim;Shin, Eun-Sang
    • Journal of Environmental Health Sciences
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    • v.41 no.4
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    • pp.241-248
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    • 2015
  • Objectives: This study was conducted to provide scientific and effective information on phytoncides, which are associated with forest healing, and to activate recreational forests. Methods: The target sites were natural recreation forests, a forest park and an arboretum, and the control sites were three urban parks. The samples were collected at a volume of 6.0 L and a flow rate of 0.1 L/min for one hour using a low volume pump and the solid adsorbent sampling method. The phytoncide compounds adsorbed in the Tenax TA tube were analyzed by a automatic heat desorption unit and GC-MS. Results: By type of recreational forest, the annual concentrations of phytoncide (monoterpene) for the forest park showed the highest concentration with $1.450{\mu}g/m^3$, while those for the arboretum showed the lowest concentration at $0.892{\mu}g/m^3$, and thus the concentration of the forest park was approximately 1.6 times higher than the arboretum. The season showing the highest concentration of phytoncides was summer (June) and the forest park was the highest among the recreational forests. The concentrations of major components for phytoncide showed in descending order: ${\alpha}-pinene$, ${\beta}-pinene$, camphene, 3-carene and limonene. The seasonal concentration of ${\alpha}-pinene$, camphene and ${\beta}-pinene$ by type of recreational forest increased in April, which is characterized by low temperature and humidity, and the seasonal concentration of camphene decreased with higher humidity. The meteorological factors which had the high correlation with the concentration of total terpene were temperature and humidity. $CO_2$ and $O_2$ showed an inverse correlation. Conclusion: The major components of phytoncide were ${\alpha}-pinene$, ${\beta}-pinene$, camphene, 3-carene and limonene in descending order of concentration. Further and systematic study on the chemical nature of individual phytoncides, and on the effect of phytoncides on humans needs to be performed.

Integrated Network System of Milk Cow Stock-Farming Facilities for Stockbreeding Management (사양관리를 위한 젖소 목장 시설 통합 네트웍 시스템)

  • 김지홍;이수영;김용준;한병성;김동원
    • Journal of Animal Environmental Science
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    • v.8 no.3
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    • pp.199-208
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    • 2002
  • This paper introduces the method to make management network about milking cow farm tasks. The object of this research was to design of biological measuring system and managing network system in a livestock farm. This auto-management system provides informations about individual cows' temperature, conductivity of milk and weight for efficient management of feeding, and milking works by a micro-processor and RS -485 type serial COM. ports. And measured bio-data which are basic informations for remote raising management are saved to user PC by serial communication between the PLC and user PC. Milking cow farm is divided into three working place to each measurement work and feed. The first working place is milking station which has two thermometers, a conduct meter and a scale set. The second working place is feeding station, and the third place is cattle cage. These are combined by network system and the PLC which is used to drive network and sub-modules. Sub-modules have a micro-process to control the sensor and to interface with network. The PLC which drive network and control sequence has two serial communication port to be linked with user PC for sending the measured data and for receiving data. Above all, in this study tells the sequence operating method by the driving scenario of breeding milk cow for livestock auto-management using the PLC and network system.

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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.

Analysis of Heat Transfer Characteristics on Multi-layer Insulating Curtains Coated with Silica Aerogel (실리카 에어로겔이 흡착된 다겹보온커튼의 전열 특성 분석)

  • Jin, Byung-Ok;Kim, Hyung-Kweon;Ryou, Young-Sun;Lee, Tae-Seok;Kim, Young-Hwa;Oh, Sung-Sik;Kang, Geum-Choon
    • Journal of Bio-Environment Control
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    • v.28 no.3
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    • pp.273-278
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    • 2019
  • The multi-layer insulating curtains used in the experiment was produced in six combinations using non-woven fabric containing aerogel and compared and analyzed by measuring heat flux and heat perfusion rates due to weight, thickness and temperature changes. Using silica aerogel, which have recently been noted as new material insulation, this study tries to produce a new combination of multi-layer insulating curtains that can complement the shortcomings of the multi-layer insulating curtains currently in use and maintain and improve its warmth, and analyze the thermal properties. The heat flux means the amount of heat passing per unit time per unit area, and the higher the value, the more heat passing through the multi-layer insulating curtain, and it can be judged that the heat retention is low. The weight and thickness of multi-layer insulation curtains were found to be highly correlated with thermal insulation. In particular, insulation curtains combined with aerogel meltblown non-woven fabric had relatively higher thermal insulation than insulation curtains with the same number of insulation materials. However, the aerogel meltblown non-woven fabric is weak in light resistance and durability, and there is a problem that the production process and aerogel are scattering. In order to solve this problems, the combination of expanded aerogel non-woven fabric and hollow fiber non-woven fabric, which are relatively simple manufacturing processes and excellent warmth, are suitable for use in real farms.

Graft-taking and Growth Characteristics of Grafted Cucumber(Cucumis sativus L.) Seedlings as Affected by Light Quality and Blink Cycle of LED Modules (LED 모듈의 광질 및 점멸주기에 따른 오이접목묘의 활착 및 생장 특성)

  • Kim, Hyeong Gon;Choi, Yu Hwa;Kim, Yong Hyeon
    • Journal of Bio-Environment Control
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    • v.28 no.2
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    • pp.143-149
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    • 2019
  • This study was conducted to investigate the graft-taking and growth of grafted cucumber seedlings as affected by light quality and blink cycle of LED modules. Four light quality treatments, namely blue, red, blue+red, white LED and four blink cycle levels of 5s/5s, 7s/3s, 9s/1s and control were provided to investigate the effect of lighting quality and blink cycle on the graft-taking and growth of grafted cucumber seedlings. Photoperiod for the control was 12/12 h. Photosynthetic photon flux, air temperature, and relative humidity for healing were maintained at $100{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, $25^{\circ}C$, and 90%, respectively. There was no significant difference in graft-taking of grafted cucumber seedlings according to light quality except the blue LED with the blink cycle of 5s/5s. Regardless of the blink cycle, there was no significant difference in graft-taking of cucumber seedlings healed under red, blue+red, and white LED modules. These results implied that the effects of light quality and blink cycle on the graft-taking were not significant. Differences in the leaf length, leaf area, and fresh weight of cucumber seedlings healed blue or red LED with the blink cycle of 9s/1s were found to be significant. There was no significant effect of the blink cycle on the growth of cucumber seedlings healed under white LED modules. The prices of white LED are gradually falling due to increased demand. Considering the manufacturing unit price of white LED modules, the cost savings of 10-15% are expected as compared to the conventional blue/red LED modules. Therefore, it was concluded that the use of white LED modules will be economical as an artificial lighting sources for healing of grafted seedlings.

Development of Summer Leaf Vegetable Crop Energy Model for Rooftop Greenhouse (옥상온실에서의 여름철 엽채류 작물에너지 교환 모델 개발)

  • Cho, Jeong-Hwa;Lee, In-Bok;Lee, Sang-Yeon;Kim, Jun-Gyu;Decano, Cristina;Choi, Young-Bae;Lee, Min-Hyung;Jeong, Hyo-Hyeog;Jeong, Deuk-Young
    • Journal of Bio-Environment Control
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    • v.31 no.3
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    • pp.246-254
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    • 2022
  • Domestic facility agriculture grows rapidly, such as modernization and large-scale. And the production scale increases significantly compared to the area, accounting for about 60% of the total agricultural production. Greenhouses require energy input to create an appropriate environment for stable mass production throughout the year, but the energy load per unit area is large because of low insulation properties. Through the rooftop greenhouse, one of the types of urban agriculture, energy that is not discarded or utilized in the building can be used in the rooftop greenhouse. And the cooling and heating load of the building can be reduced through optimal greenhouse operation. Dynamic energy analysis for various environmental conditions should be preceded for efficient operation of rooftop greenhouses, and about 40% of the solar energy introduced in the greenhouse is energy exchange for crops, so it should be considered essential. A major analysis is needed for each sensible heat and latent heat load by leaf surface temperature and evapotranspiration, dominant in energy flow. Therefore, an experiment was conducted in a rooftop greenhouse located at the Korea Institute of Machinery and Materials to analyze the energy exchange according to the growth stage of crops. A micro-meteorological and nutrient solution environment and growth survey were conducted around the crops. Finally, a regression model of leaf temperature and evapotranspiration according to the growth stage of leafy vegetables was developed, and using this, the dynamic energy model of the rooftop greenhouse considering heat transfer between crops and the surrounding air can be analyzed.

The Effect of After-school Programs on Science-related Attitude and Learning Achievement of High School Students : In the Unit of 'The Change of Weather' (방과후 학교 프로그램이 고등학교 학생들의 과학에 대한 태도와 학업성취도에 미치는 영향 : '날씨의 변화' 단원을 중심으로)

  • Keum, Kyung-Jin;Yoon, Ill-Hee
    • Journal of Science Education
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    • v.32 no.2
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    • pp.71-86
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    • 2008
  • The purpose of this study was to apply After-school programs related to sub-chapter 'The Change of Weather', and thereby to investigate the effect of After-school program on science-related attitude and learning achievement of students, and interaction between treatment methods and students' learning ability. The subjects of study consisted of 2nd grade students of sixty four students in high school. Sixty four students were divided into two categories by experimental and control groups on the basis of midterm examination before teaching treatment. The experimental groups have received four After-school programs including making models of a weather front, measurement of wind, measurement of temperature and the dew point, making a three-dimensional weather chart which were developed by researcher for six times. The control groups have received the instruction through the conventional teaching methods. Seventy questions within seven frameworks of TOSRA have been used in this study as an evaluation instrument of science-related attitude. Learning achievement has been evaluated using an instrument developed by researcher. The scores of both pre-test and post-test were estimated by ANCOVA. The results of this study can be summarized as follows. (1) After-school programs were more effective in progressing the three categories of science related attitude of high school students i.e. pleasure of science class(p<.05), reception of scientific attitude(p<.01), attitude about a science research(p<.05) than conventional teaching methods. (2) Experimental groups showed statistically significant improvement on learning achievement than control groups(p<.05). (3) The effect of treatment methods on students' learning ability has been improved in experimental groups more positively than control groups(p<.05). High level students in experimental groups showed significant improvement on learning achievement than low level students according to the representing profile plot. But there were no significant interaction between treatment methods and students' learning ability(p>.05) In conclusion, the After-school programs have positive effect on the improvement of science related attitude and learning achievement.

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Effects of High Pressure and Binding Agents on the Quality Characteristics of Restructured Pork (초고압처리 및 결착제 첨가가 재구성 돈육의 품질특성에 미치는 효과)

  • Choi, Ye-Chul;Jung, Kyung-Hun;Chun, Ji-Yeon;Choi, Mi-Jung;Hong, Geun-Pyo
    • Food Science of Animal Resources
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    • v.33 no.5
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    • pp.664-671
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    • 2013
  • The objective of this study was to investigate the effect of high pressure treatment and type of binding agents on the quality characteristics of restructured pork. For binding agents, 2% (w/w) isolated soy protein (SP), 0.5% (w/w) wheat flour (WF) and 0.5% (w/w) ${\kappa}$-carrageenan (KC) were incorporated into meat batter with or without 0.5% (w/w) glucono-${\delta}$-lactone (GdL). The restructured pork was pressurized at varying pressure levels (0.1-450 MPa) for 3 min under ambient temperature and thermal treated at $75^{\circ}C$ for 30 min. As quality parameters of restructured pork, pH, water binding properties, instrumental color and texture profile analysis were determined and compared with control (C, no binder). For type of binders, SP exhibited the best water binding properties, however, the impact on textural properties were lesser than KC and WF. The addition of GdL decreased the pH of restructured pork down to 0.4 unit, while high pressure processing prevented the moisture loss caused from pH decrease by GdL. In particular, meat restructuring efficiency of SP as a binder improved under the presence of GdL. Therefore, the present study demonstrated the potential advantages of low amount of GdL (0.5%, w/w) combined with protein based binder (SP) and high pressure processing in restructuring meat particles.