• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.5
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• pp.60-67
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• 2015

The compressor is used for many fields not only in the industrial sector, but also as a general household product. The energy consumption required for the compressor operation is very large. The reciprocation compressor is widely used as an air compressor. Regarding the reciprocating air compressor, the discharge of the gas compacted by the method of compressing the gas by using the oscillation of the piston is generated by the piston reciprocation 1 church 1 number. When compressing after compressing the air by the oscillation of the piston, the marine reciprocating air compressor is the vibration generated in the compressor and surrounding structure due to the energy of the generated inertia. If the effect of these harmful elements can be reduced, it supports the service of the vessel. In addition, accidents generated by the noise of the vibration can be prevented. Therefore, in this research, firstly, the structural analysis of the piston part was performed, the safety factor in all results was drawn based upon this, and the reliability of the interpretation was examined in order to create the optimal design for the air compressor.

• Journal of Mechanical Science and Technology
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• v.17 no.5
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• pp.751-757
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• 2003

With increasing requirements for the less harmful exhaust emissions and the better fuel economy, the conventional injectors in gasoline engines can be replaced by the air shrouded injector in order to provide improved combustion in engine operations. To find out the optimal shape of air shrouded atomizer attached to the conventional injector nozzle, the critical design parameters such as droplet size, fuel and air inlet angles, and injection angles were investigated based on experimental analyses. To explain the characteristics of fuel atomization, these experimental approaches were carried out using a Phase Doppler Particle Analyzer (PDPA) system. The droplet sizes of injected air fuel mixture were obtained by using the beam diffraction phenomenon. In order to improve the atomization effect, the various atomizers were investigated. The Saute. Mean Diameter (SMD) measured at the predetermined locations outside the atomizer represented the performance of fuel atomization. The experimental results show that the design factors and atomization mechanism needed for developing air shrouded injectors. The suggested design parameters in this paper can be a useful reference in the early design stage.

• Journal of the Korean Society of Safety
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• v.15 no.1
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• pp.72-79
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• 2000

In recent, occupational diseases in harmful working places become a social issue. It is the well-known fact that a respiration in polluted working places exert a serious effect on health of workers. Accordingly, the cutting off contaminants air originally is the best way to improve working environments. In these cases, ventilation systems should be essentially installed to dilute or exhaust the contaminated indoor air. In this study, we investigated the characteristics of ventilation system of the noxious gas in working indoor places with natural ventilation by using COMET. The numerical simulations were carried out the natural ventilation with two phase(air, dust). For turbulent flow, Reynolds stresses were closed by the standard $\kappa$-$\varepsilon$ model. The results are as follows ; 1) In the natural exhaust in the working place, the flows of the central region have a more rapid velocity vector than the right and left one. 2) Numerical results show that the distribution of contaminants concentration have greater influence on convection than the case of diffusion by government of velocity vectors. 3) To observe the velocity variation with distance, three location of distance are considered. As results, it shows that the velocity are 0.075(m/s) at y=5(m), 10(m) and mean concentration are raised 10.6% at y=5(m), 10(m). 4) We have presented the useful data for the adequate counterplan in the harmful working places by carrying out the various investigation of the natural ventilation.

• International Journal of Air-Conditioning and Refrigeration
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• v.16 no.3
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• pp.89-99
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• 2008

Indoor ozone has received attention because of its well-documented adverse effects on health. In addition to the inherently harmful effects of ozone, it can also initiate a series of reactions that generate potentially irritating oxidation products, including free radicals, aldehydes, organic acids and secondary organic aerosols (SOA). Especially, ozone reacts actively with terpene. The overarching goal of this work was to better understand ozone and terpene distributions within rooms. Towards this end, the paper has two parts. The first describes the development of a cylindrical test chamber that can be used to obtain the second order rate constant $(k_b)$ for the bi-molecular chemical reaction of ozone and terpene in the air phase. The second consists of model room experiments coupled with Computational Fluid Dynamics (CFD) analysis of the experimental scenarios to obtain ozone and terpene distributions in various turbulent flow fields. The results of CFD predictions were in reasonable agreement with the experimental measurements.

• Journal of Applied Reliability
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• v.10 no.4
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• pp.279-297
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• 2010

AQS(Air Quality Control System) is the important part of a car air conditioning system. This device intercepts automatically the influx of harmful waste gas. In this paper reliability assessment criteria for AQS are established in terms of quality certification test and lifetime test. The former quality certification test comprises general performance test and environmental test. Items which pass the test undergo lifetime test which guarantees the extent of mean lifetime with certain confidence.

• Journal of the Korea Institute of Building Construction
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• v.4 no.3
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• pp.161-167
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• 2004

The sick house syndrome is occurred from the harmful elements that the building interior materials are given off after building construction or renovation. The appropriate methods, which is to prevent sick house syndrome from spreading have to be selected before building construction or renovation. Thus, this study is to measure the density of formaldehyde, one of the volatile organic compounds after sprinkling air-assisted-catalyst on the building interior space. As a result, the emit value of formaldehyde is measured 0.07ppm that is lower than the standard of Environmental Protection Agency and World Health Organization, 0.1ppm, and the standard of Ministry of Health, Labour, and Welfare of Japan, 0.08ppm.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.3
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• pp.52-58
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• 2001

The aim of using grape-bagging paper is preventing damages by light and harmful insects during grape growth. The number of using grape-bagging paper has been increasing because advantages of using it have been confirmed. A technology to produce it has not been fully developed yet. In this study properties of the grape-bagging paper were analyzed. Results showed that air-permeability and transmitted light of grape-bagging paper were important. It was tried to see the influence of paper structure on air-permeability, transmitted light and the grapes saccharinity. For making different structure of grape-bagging paper, papers were produced with different freeness levels at several pressure conditions. Coloration time of Campbell grape with new bagging paper started about 5 days earlier than that with usual bagging paper, It was also possible to improve the saccharinity about 0.1-N0.8 Brix. Because new bagging paper has a low apparent density, it affected the saccharinity and coloration time of grape.

• Journal of the Korean Wood Science and Technology
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• v.50 no.2
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• pp.104-112
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• 2022

Indoor air quality is a very important environmental factor in modern society. However, air pollutants generated from various interior construction materials significantly affect the human body, including formaldehyde (HCHO) and volatile organic compounds that threaten public health by deteriorating indoor air quality. Effective in removing these harmful substances are porous materials, such as woodceramics. In this study, charcoal, a porous material, was added to rice husk, an agricultural by-product, and sawdust generated during the sawing process to prepare boards and ceramics at different mixing ratios, and the HCHO deodorization performance and far-infrared emission characteristics were measured. As the mixing ratio of charcoal increased, the deodorization rate of the boards and ceramics tended to increase. Overall, the deodorization rate was measured to be 80% to 90%, indicating that the boards and ceramics prepared with charcoal are suitable to be used for the purpose of deodorization. The effect of the material mixing ratio on far-infrared emissivity and emission power was insignificant.

• Journal of the Korea Furniture Society
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• v.24 no.1
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• pp.70-78
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• 2013

Indoor air quality control has been strengthened within childcare facilities and welfare communities for the elderly and infirm. I have researched the indoor air quality of kids caf$\acute{e}$s. The quality was determined by the measurement of $CO_2$ and HCHO, and the result was used in understanding of the current status of indoor air quality control. The higher level of $CO_2$ and HCHO were found in the playground area where children use compared to the area for guardians in kids caf$\acute{e}$s. And the more people in the caf$\acute{e}$s, the more $CO_2$ and HCHO were generated. It is judged that kids furniture produce harmful substances for children. Hence, the government regulations for kids caf$\acute{e}$s should be improved by reinforcing the indoor air quality control, considering that the main customers are children not adults.

• Journal of Preventive Medicine and Public Health
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• v.36 no.1
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• pp.47-53
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• 2003

Objectives : I used a case-crossover design to investigate the association between air pollution, and hospital admissions for asthmatic children under the age of 15 years in Seoul, Korea Methods : I estimated the changes in the levels of hospitalization risk from theinterquartile (IQR) increase in each pollutant concentrations, using conditional logistic regression analyses, with controls for weather information. Results : Using bidirectional control sampling, the results from a conditional logistic regression model, with controls for weather conditions, showed the estimated relative risk of hospitalization for asthma among children to be 1.04 (95% confidence interval (CI), 1.01-1.08) for particulate matter with an aerodynamic diameter less than or equal to 10m (IQR=40.4ug/m3); 1.05 (95% CI, 1.00- 1.09) for nitrogen dioxide (IQR=14.6ppb): 1.02 (95% CI,0.97-1.06) for sulfur dioxide (IQR=4.4ppb): 1.03 (95% CI, 0.99-1.08) for ozone (IQR=21.7ppb): and 1.03 (95% CI, 0.99-1.08) for carbon monoxide f10R=1.0ppm). Conclusions : This empirical analysis indicates the bidirectional control sampling methods, by design, would successfully control the confounding factors due to the long-term time trends of air pollution. These findings also support the hypothesis that air pollution at levels below the current ambient air quality standards of Korea is harmful to sensitive subjects, such as asthmatic children.