• The Journal of the Acoustical Society of Korea
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• v.36 no.4
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• pp.254-260
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• 2017

The purpose of this study is to evaluate the sound absorption characteristics of a human body according to the amount of clothing worn by using reverberation method measurement method for developing standard test dummy, which can be used for testing absorption of occupied audience chair. Test method was based on the previous study (Conti et al., 2004), each experiment is conducted in the reverberation room and a subject wearing clothes is standing in that chamber. In this experiment, the sound absorption area of each frequency band according to the wearing of various material clothing was measured. As a result of measurements, the average sound absorption area of the whole frequency band was $0.25m^2-0.48m^2$ in case of a subject not wearing outer clothes, and $0.38m^2-0.98m^2$ in case of wearing of outerwear. Polyester tops by showing the maximum value, the highest characteristics in the 800 Hz to 1 kHz band among the rest of fiber materials. The outer jacket made of the wool and cotton materials show a higher absorption area as the frequency increases to the higher frequency band. The change of the sound absorption area according to the clothing amount was divided by the thermal resistance (clo) of the worn clothes and the weight per body surface area.

• Journal of Bio-Environment Control
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• v.28 no.3
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• pp.255-264
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• 2019

In this study, we conducted the hot box tests to compare the changes in thermal insulation for the four types of multi-layer thermal screens by the used period after collecting them from the greenhouses in the field when they were replaced at the end of their usage. The main materials for these four types of multi-layer thermal screens were matt georgette, non-woven fabrics, polyethylene (PE) foam, chemical cotton, etc. These materials were differently combined for each multi-layer thermal screen. We built specimens ($70{\times}70cm$) for each of these multi-layer thermal screens and measured the temperature descending rate, heat transmission coefficient, and thermal resistance for each specimen through the hot box tests. With regard to the material combinations of multi-layer thermal screens, thermal insulation can be increased by applying a multi-layered PE foam. However, it is considered that the multi-layered PE foam significantly less contributes to heat-retaining than chemical wool that forms an air-insulating layer inside multi-layer thermal screens. For the suitable heat-retaining performance of multi-layer thermal screens, basically, materials with the function of forming an air-insulating layer such as chemical cotton should be contained in multi-layer thermal screens. The temperature descending rate, heat transmission coefficient, and thermal resistance of multi-layer thermal screens were appropriately measured through the hot box tests designed in this study. However, in this study, we took into consideration only the four kinds of multi-layer thermal screens due to difficulties in collecting used multi-layer thermal screens. This is the results obtained with relatively few examples and it is the limit of this study. In the future, more cases should be investigated and supplemented through related research.

• Korean journal of applied entomology
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• v.24 no.1 s.62
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• pp.39-44
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• 1985

This study was undertaken to select a suitable Korean tissue paper for Baermann funnel method. Ten kinds of five manufacturers were evaluated as to nematode extraction efficiency in Baermann funnel. 'Crown Hankie'(Korea Special Paper Co., Ltd.) had suitable properties in nematode permeability and strength regardless of three soil types, loamy sand, sandy loam and clay loam. The number of nematodes extracted using 'Crown Hankie' 4 ply was 198, while that of 'Cottonwool Nematode Filter' was 227. Un-perfumed tissue papers showed higher nematode extraction efficiencies than perfumed tissue papers by 53 and 23% in 'Kleenex New Softness' and 'Monaliza Finely Soft Tissue', respectively. Among the nematode extraction efficiencies by temperatures, $15^{\circ},\;25^{\circ}\;and\;35^{\circ}C$, it was highest at $35^{\circ}C$. In experiment of evaluating nematode extraction using Baermann funnel at 12 hours interval to 92 hours, 35.3 and 40.3% of nematodes were extracted after 12 and 24 hours, respectively.