• 한국주거학회논문집
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• 제25권5호
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• pp.43-50
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• 2014

This study assesses thermal environment of detached housing area by classifying buildings types with codes based on spatial characteristics and forms of the detached housing area and applying heat island alleviation measures, especially focused on FBCs (Form-Based Codes). We analyzed shapes and materials of outdoor space with 3D-CAD, which can affect the surface temperature of the case studies, focusing on heat island alleviation measures, and performed space design by applying relevant climate factors to a simulation. As to the 3D surface temperature and HIP distribution, low-temperature distribution was shown in the case studies when we applied heat island alleviation measures. FBCs (Form- Based Codes) is being developed for the purpose of creating new urban environment. This study is significant because it pays attention to the effects of surface temperatures on accumulation of sensible heat and reviews heat island alleviation measures with outdoor space shapes/materials in order to lower surface temperatures, aiming at improved pleasantness of the detached housing area.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.82-86
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• 2002

The thermal characteristics of high-speed air spindle system with built-in motor are studied. Experiment and finite difference method analysis obtain temperature rise and temperature distribution of housing. For the analysis, air fluid film model is built and temperature rise and distribution in thermal steady state are computed for each rotational speed. Generally, it is said that the heat generation of air bearing is negligible. But the heat generation in air film by heat dissipation can not be negligible especially into high-speed region of the journal. In case that the heat generation of air spindle system is high, natural frequency of the spindle system becomes lower when the thermal state is in steady-state and it means the changes of air bearing stiffness due to the change of bearing clearance. It is shown that the temperature rise of air spindle system causes thermal expansion and induces the variation of bearing clearance. In consequence the stiffness of air bearing becomes smaller.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.394-397
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• 2005

This study aims to estimate a heat island potential distribution based on the land-use types using LANDSAT/TM(1100LST April 2000) and AWS data in Daegu. The heat island potential is defined as a difference between surface temperature and air-temperature at each place. The study area was selected as about $900k km^2$ square including Daegu metropolitan area. Land-use data obtained by dividing all of Daegu metropolitan area into l-km-square three types of maps were prepared, in the 1 960s, 1970s and 2000s respectively. The types of land-use were divided into 5. Forest and farm lands have been reduced at a wide range during 40 years, most of which changed to urban area. The heat island potential distribution presented a striking contrasts according to land-use types. For example, the heat island potential of urban area was higher than $14^{\circ}$ in comparison to those of water or paddy rice areas.

• 한국환경과학회지
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• 제16권1호
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• pp.65-71
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• 2007

This study aims to estimate a urban heat island potential distribution based on the land-use types using Landsat TM(1100 LST August 2004) and AWS data in Daegu. The heat island potential is defined as a difference between surface temperature and air-temperature at each place. The study area was selected as about $900km^2$ square including Daegu metropolitan area. Land-use data obtained by dividing all of Daegu metropolitan area in- to 1-km-square three types of maps were prepared in the 1960s, 1970s and 2000s respectively. Land-use types were classified into 5 categories. Forest and farm lands have been reduced at a wide range during 40 years. Most of those changed into urban area. The heat island potential distribution presented a striking contrasts according to land-use types. For example, the heat island potential of urban area was higher than $10^{\circ}C$ in comparison to those of water or paddy rice areas.

• 한국환경과학회지
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• 제16권5호
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• pp.611-622
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• 2007

The purpose of this research was to three-criteria landuse-pattern, developing density, NDVI which were related to the heat island and find the distribution characteristic of urban surface temperature and urban heat island effects. The results of this study were as follows. According to the analysis of surface temperatures, the first grade was the outside-city like a mountain and its temperature was less than $12.18^{\circ}C$. The fifth grade was the downtown industrial area and its temperature was more than $23.54^{\circ}C$. It means Daegu-Metropolitan-City has the serious heat-island effect. the results of landuse pattern analysis, in case of fifth and forth grade, city area was occupied over 90% with residential, commercial and industrial areas, but in case of third grade, openspace was occupied over 70%. The results of developing density analysis, the temperature had high correlation with building ratio, road ratio, vegetation ratio and etc. To plan for the decrease of heat island effect needed the extension of green space, decrease of paving, but there was a limit to get the objective method for grade classification because of lacking in the basic data, the research of criteria will be accomplished continuously.

• 한국재료학회지
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• 제23권12호
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• pp.737-744
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• 2013

We demonstrated size control of Au nanoparticles by heat treatment and their use as a catalyst for single-walled carbon nanotube (SWNTs) growth with narrow size distribution. We used uniformly sized Au nanoparticles from commercial Au colloid, and intentionally decreased their size through heat treatment at 800 oC under atmospheric Ar ambient. ST-cut quartz wafers were used as growth substrates to achieve parallel alignment of the SWNTs and to investigate the size relationship between Au nanoparticles and SWNTs. After the SWNTs were grown via chemical vapor deposition using methane gas, it was found that a high degree of horizontal alignment can be obtained when the particle density is low enough to produce individual SWNTs. The diameter of the Au nanoparticles gradually decreased from 3.8 to 2.9 nm, and the mean diameter of the SWNTs also changed from 1.6 to 1.2 nm for without and 60 min heat treatment, respectively. Raman results reconfirmed that the prolonged heat treatment of nanoparticles yields thinner tubes with narrower size distribution. This work demonstrated that heat treatment can be a straightforward and reliable method to control the size of catalytic nanoparticles and SWNT diameter.

• 열처리공학회지
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• 제24권4호
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• pp.203-208
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• 2011

Recently, from general machine parts and automobile parts using carbon steel to a mold, there has been efforts for improving durability and attrition resistance of these parts. Especially, heat treatment with laser which works fast and automatically can be used for the mass production with high quality. Moreover, local heat treatment can be used to handle with complex and precise parts. Accordingly, we analyzed hardening characteristics of carbon steel using the finite element method and compare the experimental results to have more reliability. We also proved the cause of thermal deformation with temperature and stress distribution by heat treatment. After these analysis and experimental, we found that each maximum hardness of the two tests was 728 Hv and 700 Hv, on condition of $1050^{\circ}C$ heating temperature, and 2 mm/sec laser speed. We also found that difference of surface stress-distribution was occurred, and this makes deformation mode up after heat treatment.

• 한국지열·수열에너지학회논문집
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• 제11권4호
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• pp.22-27
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• 2015

Quality characteristics of Shiitake mushroom using two types of dryers, energy-efficient heat pump hot-air dryer and electric heater hot-air dryer were compared. Energy consumed during drying by heat pump hot-air dryer and electric heater hot-air dryer were 22.8 kWh and 28.9 kWh, respectively. Total polyphenol content of heat pump hot-air dryer and electric heater hot-air dryer after drying were $290.55{\pm}10.56ppm$ and $192.99{\pm}6.53ppm$, respectively. No differences were observed between dryers in reconstitution rate and browning ratio after drying. Also, there were no differences between dryers in color value and ${\Delta}E$ value after drying. Shiitake mushroom drying at $45^{\circ}C$ by heat pump hot-air dryer was proved to be more efficient in energy consumption than by electric heater hot-air dryer.

• 대한조선학회논문집
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• 제35권1호
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• pp.98-106
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• 1998

멤브레인형 가스운반선의 경우 화물창들 사이에 cofferdam을 두어 격리시키고 있는데 이 경우 극 저온 액체 화물의 영향으로 cofferdam 실내 온도는 약 $-40^{\circ}C$내외로 떨어지게 된다. 그 결과 cofferdam 및 화물창을 구성하는 bulkhead는 구조 부재로서의 허용 강도를 만족하는 온도를 유지할 수 없게 된다. 결국 heating system을 사용하여 cofferdam 실내 온도를 최소한 $5^{\circ}C$까지 올려야 하는데, 소요 pipe의 길이 산정을 위한 heat flux 산출과 pipe의 배치가 우선적으로 요청된다. 본 연구에서는 다양한 설계 조건에서의 cofferdam 내 heat flux를 각 compartment들 간의 연성 효과를 고려하여 구하고 이를 기존 계산서들과 비교 검토하여 그 타당성을 검증하였고 이를 토대로 heating system에 필요한 pipe의 길이를 산정하였다. 아울러 현재의 heating system의 대안으로 fin을 부착한 pipe로 구성된 heating coil system을 제시하고 그 효율을 비교하였다.

• 한국자동차공학회논문집
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• 제14권5호
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• pp.145-154
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• 2006

Each part of drum brake system is loaded by continual mechanical force and thermal force every time of braking, so enough strength and stability are required. Thermal characteristic is one of the important factors in drum brake systems design. This paper presents the thermal performance such as temperature distribution and thermal contact stress of drum brake system considering several braking patterns; 80th heat braking test mode, heat fade braking test mode, general road mode, steep slope road mode and off road mode. Transient heat transfer analysis and Thermo elastic contact analysis is executed to obtain the temperature distribution, and to evaluate thermal stress of drum brake by using ABAQUS/Standard code. This procedure of analysis can effectively be used to improve the quality problem of brake system and to get design guideline of the new product.