• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.768-773
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• 2009

A numerical study has been performed to investigate the thermal Performance of Solar heating system with baffle type of storage tank by using the commercial code TRNSYS. As a result, the solar fraction depends strongly on the efficiency and heat loss coefficient of solar collector as well as the heating capacity of house and the water temperature supplied to the shower. In addition, the solar fraction has been basically ranked to higher level in baffle type of storage tank than typical type of single storage tank for the range of operation condition.

• Journal of Korean Society on Water Environment
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• v.20 no.2
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• pp.120-125
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• 2004

Exposure to volatile disinfection by-products (DBPs) such as chloroform included in chlorinated tap water can occur during household activities via inhalation as well as ingestion and dermal absorption. This study was conducted to examine the significance of inhalation route of exposure since humans are unintentionally exposed to volatile DBPs while staying home. Two sets of experiments were carried out in an apartment to measure: 1) the variation of chloroform concentrations in the living room air following kitchen activities (cooking and dish-washing); and 2) the variation of chloroform concentrations in the bathroom and living room following showering. Cooking, dish-washing, and showering all contributed to the elevation of household chloroform levels. Even a few minutes of natural ventilation resulted in the reduction of the chloroform levels to the background. Estimates of daily chloroform doses and lifetime cancer risks suggested that inhalation of household air during staying home be a major route of exposure to chloroform and that ingestion be a minor one in Korean people. It is also suggested that ventilation be a simple and important measure of mitigating human exposure to volatile DBPs indoors.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.947-949
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• 1998

In this paper, the NO was oxidized $NO_2$ by using the non-thermal plasma and NOx removal characteristics were measured by showering NaOH water-solution to $NO_2$. The NO oxidation increased in the order of DC, AC, and Pulse. NOx oxidation for two stage with applied voltage was better than that for one stage with applied voltage. NO oxidation didn't depend on applied voltage. While NO oxidation was going on, NOx removal efficiency was 20-25%, however, significantly depended on the injection method of air and $H_2O$ + air. When NaOH water-solution density of 20% was showered to flue gases, NOx removal efficiency increased to 64%.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.2
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• pp.205-212
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• 2020

Objectives: The purpose of this study was to identify the needs and improvement measures of the risk assessment system through a survey of asbestos abatement companies. Methods: This study prepared a questionnaire that includes improvement measures for the risk assessment system(six questions) and the necessity of a risk assessment system for asbestos abatement(one question). The questionnaire was sent to 2,170 asbestos abatement companies and returned by 83 companies(return rate = 3.8%). We conducted frequency analysis, ANOVA, and Chi-squared testing at the 5% significance level. Results: This study analyzed the survey results and identified six main opinions on the risk assessment system and improvement measures. First, giving an advantage to companies with a high grade(S and A grades) in public bidding and/or qualification screening showed a similar preference(agree: 50.6%, disagree: 49.4%). Second, 57.6% of the respondents wanted to allow air showers along with water showers for low risk asbestos work. However, 23.2% of the respondents asserted that only a water shower should be allowed since there is no scientific evidence supporting the removal of asbestos by air shower. Third, in order to prevent missing the enrollment of workers, simply submitting a change report should be allowed when any worker is changed (40.0%). Fourth, 43% of the respondents answered that they did not know how to calculate the proper number of negative pressure units. The reasons given were a lack of guidelines or standards(38.9%), inconvenience (36.1%), and absence of education(25%). Fifth, the respondents who were favorable toward the necessity of a risk assessment system gave higher scores compared to unfavorable respondents on the necessity of the management of workers' work history(favorable respondent = 3.96 out of 5, unfavorable respondent = 2.68) and the necessity of professional training for workers(favorable respondent = 3.71, unfavorable respondent = 2.56). Finally, the respondents favorable toward a risk assessment system showed higher scores on the awareness of calculating the proper number of negative pressure units(4.79) compared to unfavorable respondents(3.3). Conclusions: The opinions of asbestos abatement companies identified through the survey in this study can be usefully utilized as fundamental information to improve the risk assessment system.

• Journal of The Korean Digital Architecture Interior Association
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• v.11 no.1
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• pp.5-13
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• 2011

This research proposed the space planing methode and diagrams of restaurant kitchens to improve hygiene by analyzing the related contents collected from books and researches in interior design and HACCP (Hazard Analysis and Critical Control Point). HACCP is an effective and scientific hygiene system for food safety in order to prevent cross-contamination from food hazards. Based on the analyses, improvement of food production environments like restaurant kitchens is necessary for food hygiene. The space planing methode of restaurant kitchens to improve hygiene are followings: The circulation planing is that the direction of movement of the food, workers, waste, and dishes should be fractionated and managed for cross-contamination prevention. The space separation planing is that the spaces in the kitchen should be classified and divided into contaminated area and non-contaminated and clean area depending on the degree of cleanliness. The zoning is space arrangement with feed-back process to check the possible points of cross-contamination and correct space arrangement until the possibility of cross-contamination disappear in kitchen. However, if cross-contamination is unavoidable in some points in restaurant kitchens, hygiene facilities such as washing rooms, pass rooms, and double doors with air-shower should be located in order to remove contamination.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.5
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• pp.653-658
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• 2011

In general, the purpose of packaging fasteners is a series of management activities to maintain the condition at the time of production until they get delivered to the end user. An automatic packing system for fasteners is consisted of bucket conveyor, slide feeder, vision inspection system, box-magazine conveyor system and automatic packing machine. Also, the automatic packing machine is consisted of six modules including charging device, clamping/opening device, sealing/cutting device, feeding/air-shower device, supplying/adjusting device and device frame, etc. In this paper, we proposed an automatic packing mechanism of the one station concept for packing work of fastener objects where the continuous batch work is performed in a finite space. The proposed one-station packing mechanism has been optimized through mechanical, dynamical, structural and fluid analyses. And it had been manufactured as the prototype of automatic packing machine. The field test for validation of performance was performed directly at the production line of bolt and screw. In the field test, this packing machine showed an efficiency of about 4.5 times the manual operation. It also showed 30% reduction in the consumption of packing materials compared to the manual operation. This automatic packing machine for fastener objects will be commercialized soon.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.9 no.1
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• pp.1-7
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• 2013

With the architectural energy saving technique such as building insulation, airtightness etc., changing the indoor temperature and shortening the air conditioning time etc. are the good methods to practice energy saving in our lives. This study aims to seek a way to realize energy saving under investigation through a questionnaire survey about energy consumption condition and energy saving perception. 93% of the respondents recognized the need for energy saving, and 67% said more energy saving would possible in homes. Viable energy saving way was questioned by five steps method. More than 50% responded 'possible' or 'seems possible' at most of the items. Whereas less than 50% responded 'possible' or 'seems possible' at the items of 'lessening the cooling time' and 'lessening the shower time'. Ages of 50s who responded 'possible' or 'seems possible' was relatively less compared to 30s and 40s.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.3
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• pp.335-341
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• 2011

In this paper, we proposed an automatic packing mechanism of one station concept for fastener objects where the continuous work is performed in a finite space. The proposed packing mechanism is composed of supporting frame, feeding supply, air shower device, clamping/opening device, batch charging device, sealing/cutting device and supply adjusting device. And, these mechanisms have been modularized through mechanical, dynamical, structural and fluid optimized design using the SMO(SimDesigner Motion) analysis module. Also, the virtual prototype was carried out using the 3-D CAD program. The packing process is consisted performed in the order of feeding, clamping, bottom sealing, cutting, opening, object charging, closing and the upper sealing. And the time of these cycles were designed to be completed in 15-20 seconds. This packing mechanism will be created as a prototype in the near future. In addition, it will be applied to the production scenes after going through a field test for the validation of performance.

• Journal of Families and Better Life
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• v.20 no.6
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• pp.219-227
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• 2002

This study was conducted to examine housing preferences among single-person households and to propose guidelines for housing design choices for single people. One hundred and sixty responses to the questionnaire developed by this researcher were analyzed utilizing frequencies, percentages, and t-tests. There were significant differences between single households and non-single households in various aspects of housing preferences. Differences were found in the desired type and size of housing, needed amount of space, and the importance of space itself. Single persons wanted to live in a small apartment, about 83.45$m^2$ (25.29 pyung) size. They consider the bathroom and the master bedroom more important than the living room and kitchen. They prefer to have specifically function-oriented rooms such as shower, home office, computer room, exercise room, or leisure space. Single persons consider information-technological facilities within an apartment very important. They would like to adopt automatic and electronic technology in the house, such as optical communication network, automatic air-cleaning system, and internet TV. Housing preferences differ significantly according to socio-demographic variables such as gender and age. I propose in this study a small-sized, information-, high-tech- and leisure-oriented design that corresponds with the actual housing preferences of the single-person households.

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.427-431
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• 2004

We use simulations of large-scale structure formation to study the build-up of magnetic fields (MFs) in the intergalactic medium. Our basic assumption is that cosmological MFs grow in a magnetohy-drodynamical (MHD) amplification process driven by structure formation out of a magnetic seed field present at high redshift. This approach is motivated by previous simulations of the MFs in galaxy clusters which, under the same hypothesis that we adopt here, succeeded in reproducing Faraday rotation measurements (RMs) in clusters of galaxies. Our ACDM initial conditions for the dark matter density fluctuations have been statistically constrained by the observed large-scale density field within a sphere of 110 Mpc around the Milky Way, based on the IRAS 1.2-Jy all-sky redshift survey. As a result, the positions and masses of prominent galaxy clusters in our simulation coincide closely with their real counterparts in the Local Universe. We find excellent agreement between RMs of our simulated galaxy clusters and observational data. The improved numerical resolution of our simulations compared to previous work also allows us to study the MF in large-scale filaments, sheets and voids. By tracing the propagation of ultra high energy (UHE) protons in the simulated MF we construct full-sky maps of expected deflection angles of protons with arrival energies $E = 10^{20}\;eV$ and $4 {\times} 10^{19}\;eV$, respectively. Accounting only for the structures within 110 Mpc, we find that strong deflections are only produced if UHE protons cross galaxy clusters. The total area on the sky covered by these structures is however very small. Over still larger distances, multiple crossings of sheets and filaments may give rise to noticeable deflections over a significant fraction of the sky; the exact amount and angular distribution depends on the model adopted for the magnetic seed field. Based on our results we argue that over a large fraction of the sky the deflections are likely to remain smaller than the present experimental angular sensitivity. Therefore, we conclude that forthcoming air shower experiments should be able to locate sources of UHE protons and shed more light on the nature of cosmological MFs.