• Biomedical Science Letters
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• v.10 no.2
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• pp.129-135
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• 2004

The study was carried out through measuring the temperature and humidity of the indoor/outdoor space and the distribution of interior thermal condition, and investigating the effect of loess materials on human body. The purpose of this study is to analyze the change of dry bulb temperature and relative humidity and correlation of thermal reaction of human body with ASHRAE (American Society of Heating, Refrigerating and Air-conditioning) comfort chart in the loess interior space. In the view point of biomedical sciences, loess interior space provides optimum thermal conditions for human thermal sensation.

• Journal of the Korean Home Economics Association
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• v.28 no.2
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• pp.57-72
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• 1990

The purpose of this study were ; (1) to analyze the relationship between actual housing condition and housing satisfaction with socio-demographic and housing characteristics of respondents and (2) to present the device on the quality of housing environment in low-income families. The sample was a proportional, stratified, random sample of 299 low-income families in Deajeon. The major findings were as follows: 1) The wholey, actual housing conditions were not good; especially the worst conditions appeared exterior walls, roof, kitchen, bath and toilet, heating, noise, recreation facilities as play-ground. 2) Actual housing condition has been found to be related to income, tenure(rent or own), persons/room. In the relation of the socio-demographic and housing characteristics, actual housing condition, housing satisfaction, income and persons/room were found to be a significant explanatory variable in actual housing condition. And actual housing condition ws appeared to be the strongest variable in housing satisfaction. 3) Housing of the low-income families should be improved physical aspects of the environment and be reflected in need of the occupant that based on the social-welfare housing concept.

• Journal of the Korean housing association
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• v.15 no.1
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• pp.175-183
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• 2004

The purpose of this study was to identify the actual condition of residential environment for the elderly residing in Daejeon. The data were collected through interviews and structured questionnaires. The sujects were 583 elderly people over the age of 65 in Daejeon. Sociodemographic characteristics, living characteristics, housing characteristics, neighborhood environment types, actual usage condition of neighborhood environment, relationship between sociodemographic characteristics and actual usage of neighborhood environment, actual condition of unit interior, were surveyed. The data were analyzed with frequency, percentage, χ²-test, mean using the SPSS package. The major findings were as follows. Features of unit interior which pointed generally were deterioration, soundproofing and size. Features of unit interior which need to be carefully planned were removal of height difference of entrance, removal of the thresholds, installation of emergency bell and room heating control facility. The facilities provided highly within the subject's residential environment were the eldery facility, church, hospital, bank, restaurant, beauty salon/barbershop, supermarket. and the facilities provided lowly were recreational facility, library, elderly school.

• Journal of the Korea Institute of Building Construction
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• v.10 no.2
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• pp.97-104
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• 2010

This study evaluated the energy efficiency of a windows system using built-in blinds, with regard to their insulation performance and their blocking of solar radiation. The study took advantage of the "Physibel Voltra" program as a physical simulation of heat transfer. To simulate the "Physibel Voltra" program, I practiced a mock-up test to determine heating quality and translation condition. I analyzed the propensity to annual energy consumption, the annual quantity of heat transfer, and the annual cooling and heating cost through a computer simulation for one general household in an apartment building. In the test, it was found that compared to a general windows system, a windows system with built-in blinds reduced the annual heat transfer by 10% in cooling states and by 11% in heating states when the blind was up. When the blind was down, the windows system with built-in blinds reduced the annual heat transfer by 25% in cooling states and 30% in heating states. When a windows system with built-in blinds is compared with a general windows system, the quantity of cooling and heating loads is reduced by 283.3kw in cooling states and 76.3kw in heating states. This leads to a reduction in the required cooling and heating energy of 359.6kw per house. It is thus judged that the use of a windows system with built-in blinds is advantageous in terms of reducing greenhouse gas emissions, because the annual TOE (tons of oil equivalent) per house is reduced by 0.078TOE, while $tCO_2$ is reduced by $0.16tCO_2$. In addition, compared with a general windows system, the cost of cooling and heating loads in the system reduces the annual cooling cost by 100,000won, and the annual heating cost by 50,000won. Ultimately, this means that cooling and heating loads are cut by 150,000won per year.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2004.11a
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• pp.50-50
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• 2004

• Proceedings of the Korean Nuclear Society Conference
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• 2002.05a
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• pp.323-323
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• 2002

• Journal of Advanced Marine Engineering and Technology
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• v.17 no.4
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• pp.100-106
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• 1993

A study on optimizing the friction welding of copper(C1100) to aluminium(A1050) for developing the electrical sleeve was experimentally carried out and also on real-time nondestructive evaluation of the friction weld quality (strength) was accomplished by acoustic emission technique. The results obtained are summarized as the following ; 1) The heating upset $U_1$(mm) or total upset U(mm) tends to increase according to the increase of heating time $t_1$(sec). The relations between $U_1$ and $t_1$ or U and $t_1$are computed as follows when n=2000rpm, $P_1$=4, $P_2$=8kgf/$mm^2$, and $t_2$=6sec. U=1.6$e^{0.39t_1}$ $U_1$=3.65$e^{0.25t_1}$. 2) It was notified that the proper welding conditions by considering on both strength with more than 100% joint effieciency and toughness are heating time of 1.5-2.25 sec under n=200rpm, $P_1$=4, $P_2$=8kgf/$mm^2$, $t_2$=6sec. 3) It was confirmed that both AE total counts(N, counts) and the weld tensile strength (${\sigma}$, kgf/$mm^2$) of the welded joints increase as the increase of heating time, respectively, the relations between N and $t_1$, ${\sigma}$ and $t_1$ are computed from data points by regression analysis using the least square method as follows in case of the above proper condition ; N=50108+23917(ln $t_1$)${\sigma}$$=11.85+2.06(ln $t_1$). 4) Both empirical and calcularated equations of relationship between .sigma. and N are very coincident with a high reliability, as the following in case of the above proper welding condition ; Calculated : ${\sigma}$=0.00008N+7.5 Empirical :${\sigma}$= $8.17e^{0.0000072N}$. 5) It was confirmed that the real-time nondestructive weld strength evaluation for friction welding of copper(C1100) to aluminium(A1050) could be possible by acoustic emission technique.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.1
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• pp.172-181
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• 1993

Pseudo-Brayton cycle is defined as an ideal Brayton cycle admitting the difference between heat capacities of working fluid during heating and cooling processes. The endo-pseudo-Brayton cycle which is a pseudo-Brayton cycle with heat transfer processes is analyzed with the consideration of maximum power conditions and the results were compared with those of the endo-Carnot cycle and endo-Brayton cycle. As results, the maximum power is an extremum with respect to the cycle temperature and the flow heat capacities of heating and cooling processes. At the maximum power condition, the heat capacity of the cold side is smaller than that of heat sink flow. And the heat capacity of endo-Brayton cycle is always between those of heat source and sink flows and those of the working fluids of pseudo-Brayton cycle. There is another optimization problem to decide the distribution of heat transfer capacity to the hot and cold side heat exchangers. The ratios of the capacies of the endo-Brayton and the endo-pseudo-Braton cycles at the maximum power condition are just unity. With the same heat source and sink flows and with the same total heat transfer caqpacities, the maximum power output of the Carnot cycle is the least as expected, but the differences among them were small if the heat transfer capacity is not so large. The thermal efficiencies of the endo-Brayton and endo-Carnot cycle were proved to be 1-.root.(T$_{7}$/T$_{1}$) but it is not applicable to the pseudo-Brayton case, instead it depends on comparative sizes of heat capacities of the heat source and sink flow.w.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.3
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• pp.186-195
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• 2000

In this paper, partial discharge (PD) measurement was performed to evaluate the quality of the cable joint and termination constructions. The resistive coupling technique for PD detection using resistivity of semiconducting layer of the cable in the accessories, such as joints and terminations. With high frequency PD (HEPD) measurement, an excellent sensitivity below 20pC could be achieved under unshielded condition. The localization of the defects in the accessories could be identified. During heating cycle, PDs were monitored and analyzed. At that time, the PDs were dependent on the temperature of the heating cycle and showed cyclic behaviors, which were attributed to local delamination of the interfaces, between epoxy unit and stress relief cone(SRC) and between SRC and cable, due to the difference of thermal expansion. As a conclusion, HFPD measurement technique was proven to be an effective diagnostic method for qualification of extra high voltage (EHV) cable accessories. With this technique, the optimal design of the components of the accessories could be verified not only in an early stage but also under operating condition. This technique would result in the improvement of the reliability of the EHV cable accessories.

• Transactions of Materials Processing
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• v.7 no.3
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• pp.215-224
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• 1998

A semi-solid forming has a lot of advantages compared to the die casting. squeeze casting and conventional forging. therefore, semi-solid forming process is now becoming industrial interest for the production of metal components and metal matrix composites. However the material behaviour in the semi-solid temperature range is not sufficiently known although it controls the whole process through forces and geometry evolutions because the behaviour of metal slurries is complex. The semi-solid materials(SSMs) fabricated under electric-magnetic stirring condition is necessary to be applicated in forming process. A reheating conditions were studied with the reheating time holding time and reheating temperatures. The microstructure of SSM(specimen size : d39${\times}$h85) at the condition of heating time 10min and heating temperature 590${\circ}C$ is the most globular and finest one. The microstructure of SSM(specimen size : d76${\times}$h60) reheated under the three step reheating conditions is most globular and finest.