• 설비공학논문집
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• 제14권12호
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• pp.1047-1055
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• 2002

The present study is to investigate the pressure wave characteristics and the absorption of the maximum and minimum pressure generated by instantaneous valve closure and opening at the end of the straightening copper Piping system with and without an air chamber. Also, life of air chamber is investigated. Experiments were conducted under the following conditions: initial pressure of 1～5 bar, flow velocity of 0.5～3.0 m/s, water temperature of$20^{\circ}C$ and air chamber volume of 45.1～449.5$cm^3$ The results of the study can be used in sizing air chamber and selecting the water hammer absorbtion apparatus.

• KIEAE Journal
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• 제9권4호
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• pp.17-22
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• 2009

It is common to design the duct branches where to supply the required air flow for individual room in residential apartment house. However it is difficult to adjust the air volume adequately in small air duct branches in residential ventilation system. The purpose of this study is to figure out the performance of Multidrop chamber coupling system for the residential ventilation system. The experiments were designed to simulate apartment of $84m^2$ and established multidrop chamber duct and general duct on the ceiling of the apartment. Distribution performance of air supply rate were evaluated in this experiments. As a result, distribution performance of air supply rate in the general duct is different from designed air supply rate by about 35% ~ 50% and about 10% in the multidrop chamber system. In additional the sound insulation performance of the multidrop chamber system decreased about 20% compared with general duct system. Therefore, the multidrop chamber system is considered to satisfy proper air supply rate of each room and to improve the sound insulation performance in apartment Houses.

• 한국항만학회지
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• 제8권1호
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• pp.31-40
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• 1994

Experimental study is carried out to verify the advantages of an air chamber structure in controlling the wave transformation and its dynamic responses. The open, cross and vertical mooring systems are employed in experiments to investigate the variations of wave transmission ratio, natural period of the structures and tensile force acting on the mooring line according to the change of the initial air depth inside the air chamber structure. Experimental results show that the air chamber floating structure expresses the smaller wave transmission ratio and tensile force acting on the mooring line than general one without air chamber, expecially in the long period region of incident wave. Therefore, it is concluded that the air chamber structure suggested in this study can play good roles as a wave controlling castal structure, and a substitute structure of a general floating structure.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.762-767
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• 2009

Some types of semi-Volatile organic compounds (SVOC) that are emitted from plastics used in building materials and household appliances have associated health risks, even at low concentrations. In this study, micro chamber method for measuring SVOC is introduced and SVOC such as di (2-ethylhexyl) phthalate and butylated hydroxyltoluene emitted a flooring material were measured using a micro chamber method. Airflow characteristics in a micro test chamber deeply depended on air exchange rate. From the evaluation using an index of air change efficiency, such as the air age and the coefficient of air change performance, a fixed air exchange rate of $1.5\;h^{-1}$ in the micro chamber is desirable.

• 동력기계공학회지
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• 제17권2호
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• pp.121-127
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• 2013

The air spring is used widely because of the easy change of spring constant, and, a superior vibration and shock insulation performance. Among the apparatus using the merits of that, the air spring connected an auxiliary chamber has been developed and used as a component of suspension system for an automobile and a railroad car. The purpose of this study is to suggest a design method reflecting heat transfer effect for an air spring system connected auxiliary chamber. In order to do so, this study investigates change of reaction force along with variations in heat transfer coefficient, and, analyzes an effectiveness of a heat transfer characteristics of an auxiliary chamber for external force attenuation characteristics and impedance characteristics of an air spring connected an auxiliary chamber.

• 한국환경농학회지
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• 제2권2호
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• pp.103-107
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• 1983

생활탄(生活炭) 및 이산화(二酸化)망강필타로 공기(空氣)를 로과(瀘過)한 정화실(淨化室)과 공기(空氣)를 그대로 송입(送入)한 비정화실(非淨化室)로 구분(區分)하여 재배(栽培)한 수도(水稻)에 대(對)한 photochemical oxidants 피해발생(被害發生)은 공기정화실(空氣淨化室)에서 생육(生育)한 수도(水稻)에는 인정(認定)되지 않았으나 비정화실(非淨化室)에서는 10pphm 이상(以上)의 photochemical oxidants가 발생(發生)한 다음날에 2회(回) 가시피해증상(可視被害症狀)이 관찰(觀察)되었다. 공기정화실(空氣淨化室)의 수도(水稻) 생육양(生育量)은 지상부(地上部) 및 근부(根部) 모두 비정화실(非淨化室)보다 증가(增加)하였으며 특(特)히 근부(根部)의 생육량(生育量) 증가(增加)가 현저(顯著)하였다. 식물(植物)의 기공개폐(氣孔開閉)와 밀접(密接)한 관계(關係)가 있는 ABA 함량(含量)은 비정화실(非淨化室)의 수도(水稻)가 정화실(淨化室)의 수도(水稻)보다 높아 photochemical oxidants에 의(依)하여 식물체내(植物體內) ABA 함량(含量)이 증가(增加)되었다. 외기(外氣)를 정화(淨化)하므로서 근활력(根活力)이 현저(顯著)히 증가(增加)하여 photochemical oxidants 피해(被害)에 의(依)하여 근활력(根活力)이 현저(顯著)히 감소(減少)하는 것이 확인(確認)되었다.

• 한국대기환경학회지
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• 제19권4호
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• pp.437-449
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• 2003

A multi-functional indoor smog chamber was designed and evaluated to investigate photochemical or water vapor reaction mechanisms of air pollutants. Various smog chamber experiments could be conducted using ambient air or purified air in this smog chamber. The smog chamber consisted of a housing, a Teflon bag, blacklights, injection ports, sampling ports, and utility facilities. The characteristics of light source, the wall losses of air pollutants, and the quality of purified air were experimentally investigated. The maximum NO$_2$ photolysis rate was 1.10 min$^{-1}$ . In a 2.5-m$^3$ Teflon bag, the wall losses of ambient $O_3$, NO, and NO$_2$ were 1.2~2.4$\times$10$^{-3}$ min$^{-1}$ , 0.7~2.0$\times$10$^{-3}$ min$^{-1}$ , and 0.4~2.0$\times$10$^{-3}$ min$^{-1}$ , respectively. The wall loss of ambient particles ranging 0.05 to 0.2 ${\mu}{\textrm}{m}$ was 1.8~5.4$\times$10$^{-3}$ min$^{-1}$ , which was slightly higher than those of ambient gaseous species. The purified air supply system provided high quality of air with NO$_{x}$ < 1 ppb, and total hydrocarbons < 5 ppb.b.

• 설비공학논문집
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• 제12권8호
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• pp.782-790
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• 2000

A numerical study has been conducted to characterize the transient pressure in a building water supply system with an air chamber by utilizing a commercial code that employs the method of characteristics. Some results produced for the purpose of verification in the study agree quite well with the previously reported. Several parameters are then varied. Among them are the valve closure time, the wave speed, the static pressure, the polytropic exponent, the air chamber volume, the inner diameter and the shape of orifice in the air chamber, etc, while the water temperature and velocity are kept constant at $20^P{circ}C $,/TEX> and 0.8 m/s, respectively, Results reported in this parametric study may be useful to understand the unsteady behavior of the system.

• 설비공학논문집
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• 제4권1호
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• pp.57-64
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• 1992

A computer program was developed for the prediction of transient flow in a water supply system. where an air chamber is installed to reduce the water hammering. The governing equations based on a characteristic method are solved using a finite difference method. A design process of an air chamber is shown in the present paper considering the effects of the initial air volume and the discharge coefficients of the orifice on the total volume and over-all performance of the chamber.

• Toxicological Research
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• 제5권2호
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• pp.97-104
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• 1989

A new exposure system was developed to generate p-dinitrobenzene (p-DNB) containing atmosphere. A glass column was filled with small glass beads coated with the chemical. The p-DNB containing medium was heated to a temperature beyond the boiling point of p-DNB. A stream of air flow was forced to pass through the column and let it mixed with fresh air before introducing into an inhalation chamber. The concentration of p-DNB in the chamber air was measured by direct assaying the air directly and by sampling the chemical using a microfilter installed in the chamber.