• Journal of the Korean Institute of Landscape Architecture International Edition
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• 제2호
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• pp.120-129
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• 2004

Urban stream restoration projects can improve water quality, wildlife habitats, urban landscape, outdoor recreation spaces, and urban microclimate. The objectives of this research were to investigate temperature cooling effect of urban streams by using satellite imagery, to evaluate environmental variables related to stream cooling effect, and to estimate the cooling effect of the Cheonggye stream restoration project of Seoul, Korea. Findings of this research can be summarized as follows. First, a method of estimating temperature distribution around urban streams by using satellite imagery was developed. Scatter plots of distance from stream edges and average temperature obtained through multiple buffering were used for the estimation. Second, urban temperature cooling effect of streams was estimated by comparing background temperature and temperature of each buffer zone. Third, environmental factors affecting stream cooling effect were also identified. Fourth, the temperature cooling effect of the restoration project was estimated based on three scenarios. An estimated cooling effect based on the average cooling effect of existing tributaries showed the most significant effect; $2.0^{\circ}C$ lower than the present level at the edge of the renovated stream. It was estimated that the temperature of the same area would be $1.4^{\circ}C$ cooler than the present level if the cooling effect of the Yangjaechun was used as the bench mark But the effect would be $1.2^{\circ}C$ lower than the present level if environmental variables related to the temperature cooling effect of urban streams were used as the bench mark.

• 한국의류산업학회지
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• 제22권2호
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• pp.250-260
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• 2020

The purpose of the present study was to explore the most effective body region and cooling temperature to alleviate heat strain of workers in hot environments. We developed liquid cooling hood, vest, sleeves and socks and applied the water temperatures of 10, 15, 20, and 25℃ through the liquid cooling garments in a hot and humid environment (33℃ air temperature and 70% RH air humidity). A healthy young male participated in a total of 16 experimental trials (four cooling garments × four cooling temperatures) with the following protocol: 10-min rest, 40-min exercise on a treadmill and 10-min recovery. The results showed that rectal temperature, mean skin temperature, and ratings of perceived exertion during exercise; heart rate and diastolic blood pressure during recovery; and total sweat rate were lower for the vest condition than other garment conditions(p < .05). However, there was no differences in mean skin temperature among the four cooling garments when we compared the values converted by covering area(%BSA). When we classified the results by cooling temperature, there were no consistent differences in thermoregulatory and cardiovascular responses among the four temperatures, but 25℃ water temperature was evaluated as being the most ineffective cooling temperature in terms of subjective responses. In conclusion, the results indicated that wearing cooling vest with < 20℃ cooling temperature can alleviate heat strain of workers in hot and humid environments. If the peripheral body regions are cooled with liquid cooling garments, larger cooling area with lower cooling temperature than 10℃ would be effective to reduce heat strain of workers. Further studies with a vaild number of subjects are required.

• Journal of Mechanical Science and Technology
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• 제14권8호
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• pp.851-860
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• 2000

Temperature field and cooling rate are important parameters to influence the properties of clad layer and the heat affected zone. In this paper the temperature field and cooling rate of laser cladding are studied by a two-dimensional time-dependent finite element model. Experiment has been carried out by Nd:YAG laser cladding with wire feeding. Research results indicate that at the beginning of cladding, the width and depth of melt pool increase with cladding time. The cooling rate is related to position, cladding time, cladding speed, and preheating temperature. The temperature near melt pool changes rapidly while the temperature far from melt pool changes slowly. With the increase of cladding time, cooling rate decreases. The further the distance from the melt pool, the lower the temperature and the slower the cooling rate. The faster the cladding speed, the faster the cooling rate. The higher the preheating temperature, the slower the cooling rate. The FEM results coincide well with the experiment results.

• Journal of Biosystems Engineering
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• 제24권1호
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• pp.31-40
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• 1999

The objective of this study were to develop a cooling simulation model for fixed-bed of rough rice and to analyze the factors affecting cooling time of rough rice. A computer simulation model based on equilibrium conditions between grain and air was developed to predict temperature and moisture content changes during cooling of rough rice. the result of t-test showed that there were no significant differences between predicted and measured temperature changes on significance model agreed well with measured values. This cooling simulation model was applied to analyze the effect of some factors, such as air flow rate, cooling air temperature and humidity, initial grain temperature and moisture content, and bed depth, on cooling time of rough rice. Cooling rate increased with increase of air flow rate and bed depth whereas it decreased with increase of cooling air temperature and humidity and initial grain temperature. Among these factors, the most important factor was air flow rate. Specific air flow rate of 0.35㎥/min㎥ was required for cooling rough rice in 24 hours.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1995년도 추계학술대회 논문집
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• pp.37-43
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• 1995

The cutting process of cage motor rotor require high precision and good roughness, the surface roughness fo cutting face is very important factor with effect on the magnetic flux density of cage motor rotor. The paper describes a cause of decrease in the cutting force and roughness on low temperature cooling tool by means of analysis on the mechanism of force system at cutting condition and experimental findings. The main results as compared with the room temperature cutting are as follow : 1) The cutting resistance decreased due to low temperature cooling tool. 2) The surface roughness decreased due to low temperature cooling tool. 3) The low temperature cooling tool effected machinability of the cutting direction in machined surface. 4) The low temperature cooling decreased burr of corner in feed direction.

• 오토저널
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• 제14권2호
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• pp.34-43
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• 1992

The purpose of this study is to consider the performance and exhaust characteristics in the practical engine according to the cooling water temperature change of engine and to set up the optimum cooling condition and to obtain the optimum operating condition of thermostat in the cooling system. In order to accomplish the purpose of this study, authors have used the following procedure. 1. This study is to investigate the influence of the cooling water temperature on the engine performance and the exhaust gas, authors regulated the cooling water temperature by using the special closing circuit and measured the concentration of exhaust gas by using the exhaust gas measuring system in the exhaust pipe. 2. This study carried out the experiment by regulating the opening degree of throttle valve and engine speed in the dynamometer and by changing the cooling water temperature, at the same time kept air-fuel ratio constant and made the spark ignition time MBT(Minimum spark advance for Best Torque) 3. This study measured the cooling water temperature by using the K-type thermocouple centring around the easy over-heated parts and by installing a special closing circuit. Therefore, in this study, authors intend to examine the influence of the cooling water temperature on the engine performance, exhaust gas and present the basic materials needed in the engine design including the optimum operating time control system for the cooling water temperature.

• 한국식품저장유통학회지
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• 제4권3호
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• pp.237-243
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• 1997

Numerous variables affect product cooling rate of pressure cooling system for fruits and vegetables. These include carton vent area, initial and desired final product temperature, flow rate and temperature of the cooling air, product size, shape and thermal properties and product configuration(whether in bulk or packed in shipping cartons). This study was carried out to determine the influence of each of these variables as they affect cooling time. The opening ratio and number of the vent hole were recomended as 4∼10% and 2∼4ea., respectively, for a minimum alt flow resistance and for a uniform air flow pattern. In the cooling experiment for tomatoes and mandarins, optimum air flow rate was 0.04 m3/min.kg in terms of energy saving. The cooling air temperature should be about 2$^{\circ}C$ less than the desired final product temperature for reducing cooling time.

• 대한의용생체공학회:의공학회지
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• 제38권5호
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• pp.232-236
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• 2017

In this study, We investigated the effect of foot cooling on the reduction of body temperature after hard exercise at the high temperature of $40^{\circ}C$. We performed a total of 30 subjects, and the subjects performed treadmill exercise for 30 minutes. We produced the cooling device to cool the foot using Peltier module. After the end of the exercise, We performed normal recovery method and cooling recovery method(one foot, both feet) for 1 hour on the same indoor environmental conditions and confirmed the change of body temperature of subjects. The results of deep body temperature measurement showed average $38.78{\pm}0.22^{\circ}C$ to $38.54{\pm}0.15^{\circ}C$ when the normal recovery method was performed. Cooling recovery method on one foot showed average $38.69{\pm}0.14^{\circ}C$ to average $38.06{\pm}0.17^{\circ}C$ and Cooling recovery method on both feet showed average $38.69{\pm}0.15^{\circ}C$ to average $37.84{\pm}0.21^{\circ}C$. There was a significant difference between the normal recovery method and the one foot cooling recovery method(p < .05), there was a significant difference between the normal recovery method and the both feet cooling recovery method(p < .05) and there was a significant difference between the one foot cooling recovery method and the both feet cooling recovery method(p < .05). Body temperature showed the lowest decrease rate when the normal recovery method was performed, and body temperature showed the highest decrease rate when the both feet cooling recovery method was performed. Therefore, recovery of cooling on the foot after hard exercise have decreased body temperature, delay fatigue in the body, and will be contributed to improvement of athlete performance.

• 대한기계학회논문집
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• 제16권6호
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• pp.1150-1155
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• 1992

본 연구에서는 제철소 열연공정의 냉각효율 개선을 위한 기초연구로 수행되었 다. 전열면의 초기온도가 900.deg. C이상일 때 층류 냉각방식에 의한 고온강판의 냉각특 성에 영향을 주는 모든 인자를 엄밀히 고려하는 것은 매우 어려운 일이다.따라서 본 연구에서는 노즐과 고온면 사이 거리(L), 유량(Q), 냉각 초기온도 등을 실제 작업 조건에 가깝게 변화시켜 가면서 수냉반경의 변화를 중심으로 전열면의 냉각 특성을 해 석하였다.

• 한국정밀공학회지
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• 제23권10호
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• pp.60-67
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• 2006

This paper presents the temperature control in aluminum plate with Peltier module. From the experimental work, Peltier module is used to control the temperature of small aluminum plate for both heating and cooling with the control of current and fan ON/OFF. And current control of Peltier module was accomplished by PWM method. As a result of experiments, it is proper that operate cooling fan only while cooling duration and there exist a proper cooling current to drop temperature rapidly. It takes about 125sec to control temperature of aluminium plate between $30^{\circ}C$ and $70^{\circ}C$ and about 70sec between $40^{\circ}C$ and $60^{\circ}C$, in ambient temperature $28^{\circ}C{\sim}29^{\circ}C$ while cooling fan is operated only cooling duration. With the cooling current, temperature control of aluminum plate was accomplished more rapidly in comparison without cooling current. Future aim is to realize more rapid temperature control and develop SMHA(special metal hydride actuator) by using Peltier module as a heating and cooling source.