• The KSFM Journal of Fluid Machinery
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• v.12 no.5
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• pp.25-32
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• 2009

A study is conducted to improve the suction performance on suction devices which are used to remove polluted air generated by welding or machining process in a spacious working place of industry. Air-curtain is applied around the inlet of suction duct to interrupt the inflow of fresh air from the downstream region where is located opposite to the polluted air source. Two different air-curtain devices, such as a $45^{\circ}$ backward and a fully backward, are adopted. Suction region is experimentally investigated by measuring the suction velocities using a hot-wire anemometer. Contours of the suction velocity are compared with the computed results. The suction condition is selected to 110,000 Reynolds number which is widely used on typical suction devices, and a width of blowing passage for creating the air-curtain is chosen to 9.38% of the suction duct diameter. The experimental results show that the suction performance obtained with the $45^{\circ}$ backward air-curtain was better than that obtained with the fully backward air-curtain. On the suction duct using the $45^{\circ}$ backward air-curtain, the suction region estimated on basis of the 0.4m/sec is improved by 66% at the same input power.

• 한국전산유체공학회:학술대회논문집
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• 1995.10a
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• pp.160-168
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• 1995

This paper describes computational efforts on the various energy and environmental problems using Patankar's SIMPLE method. The specific problems included in this study are : pollutant and flammable material dispersions in open and confined areas, aerator-induced flow in a lake for DO(dissolved oxygen) concentration, primary clarifier for water and waste water treatment, hood ventilation in workplace, cyclone and LNG combustors and Dow chlorination reactor. A control-volume based finite-difference method is employed together with the power-law scheme. The pressure-velocity coupling is resolved by the use of the revised version of SIMPLE, says SIMPLER and SIMPLEC. The Reynolds stresses are closed using the standard or the RNG $k-{\varepsilon}$ models. Turbulent reaction is modeled using two fast chemistry methods such as eddy breakup and conserved scalar models. Further, a nonequilibrium model is developed for the application of the chlorination process in the Dow reactor. Other important empirical models and physical insights appeared in this study are presented and discussed in a brief note. The computational method developed in this study is considered, in general, as a viable tool for the design and determination of the optimal condition of various engineering system of interest.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.7
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• pp.616-623
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• 2007

A dual micro gas sensor array was fabricated using nano sized $SnO_2$ thin films which had good sensitivities to CO and combustible gases, or $H_2S$ gas for air quality sensors in automobile. The already existed air quality sensor detects oxidizing gases and reducing gases, the air quality sensor(AQS), located near the fresh air inlet detected the harmful gases, the fresh air inlet door/ventilation flap was closed to reduce the amount of pollution entering the vehicle cabin through HVAC(heating, ventilating, and air conditioning) system. In this study, to make $SnO_2$ thin film AQS sensor, thin tin metal layer between 1000 and $2000{\AA}$ thick was oxidized between 600 and $800^{\circ}C$ by thermal oxidation. The gas sensing layers such as $SnO_2$, $SnO_2$(pt) and $SnO_2$(+CuO) were patterned by metal shadow mask for simple fabrication process on the silicon substrate. The micro gas sensors with $SnO_2$(+Pt) and $SnO_2$(CuO) showed good selectivity to CO gas among reducing gases and good sensitivity to $H_2S$ that is main component of bad odor, separately.

• Journal of the Korean Solar Energy Society
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• v.22 no.1
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• pp.67-72
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• 2002

Solar Air Systems (SAS) have unique advantages for space heating and tempering ventilation air. Air, unlike water, needs no protection against freezing nor are leaks damaging to the building structure or its contents. In contrast to glazed collector, unglazed steel solar collector may have higher efficiencies over glazed flat collector due to the absence of the glass. Therefore, the monitoring of SAS is so important to evaluate actual performance of SAS for right applications. This study is to provide a testing method with a movable test cell developed in KIER to evaluate the thermal performance of SAS based on international standard method ASHRAE 93-86, "Method of Testing to Determine the Thermal Performance of Solar Collectors". The monitoring tool used advanced technique LabVIEW 6i with portable notebook computer. Sample results have been obtained to access the performance of a reference and a target SAS module. The process and tool introduced here could be used to provide a performance verification data for future implementation study applications.

• Journal of the Korean Wood Science and Technology
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• v.42 no.5
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• pp.615-623
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• 2014

Increases of public attention on healthy environment lead to the regulation of indoor air quality such as Clean Healthy House Construction Standard. This standard covers emission of total volatile organic compounds (TVOCs) (e.g., formaldehyde, benzene, and toluene), ventilation, and use of environmentally-friendly products or functional products. Moisture absorption and desorption abilities are a recommended functionality for improving indoor air quality. In this study, moisture absorption and desorption capacities of carbonized board from wood-based panels and other materials were determined by using UNT-HEAT-01 according to ISO 24358:2008. Pine had higher moisture absorption and desorption capacities ($49.0g/m^2$ and $35.3g/m^2$, respectively) than hinoki cypress, cement board, gypsum board, oriented strand board, and medium density fiberboard (MDF). The moisture absorption and desorption capacities differed considerably according to the wood species. After carbonization process at $400^{\circ}C$, the absorption and desorption ability of MDF increased to 38% and 60%, respectively. However, moisture absorption and desorption capacities decreased with increasing carbonization temperature, but they were still higher than original MDF. Therefore, it is suggested that carbonization below $600^{\circ}C$ can improve moisture absorption/desorption capacities.

• KIEAE Journal
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• v.13 no.2
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• pp.39-46
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• 2013

Recently, the field of construction is putting a variety of effort into reducing CO2, since global warming is being accelerated due to climate changes and the increase of greenhouse gas. For reduction of CO2 in the field of construction, it is required to make plans to cut down heating energy of buildings and especially, it is urgently needed to cut down energy of residential buildings in rural area where occupies the majority of consumption of petroleum-based energy sources. Therefore, this research compared and analyzed the actual energy consumption, by evaluating energy performance of a detached house applying passive house design components for reduction of energy. As the result, energy consumption showed remarkable differences, according to the operation of a heat recovery ventilation unit which is one of passive house design components, and building energy consumption displayed remarkable differences, too, depending on the difference of airtightness performance during building energy simulation conducted in process of design. Based on these results, the importance of airtightness performance of passive house was verified. The result of the actual measurement of energy consumption demonstrated that LNG was most economical amongst several heat resources yielded, on the basis of LPG source energy consumption measured within a certain period of time, and it was followed by kerosene. LPG was analyzed to have a low economic efficiency, when used for heating.

• Clinical and Experimental Pediatrics
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• v.53 no.12
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• pp.979-984
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• 2010

Recent progress in neonatal medicine has enabled survival of many extremely low-birth-weight infants. Prenatal steroids, surfactants, and non-invasive ventilation have helped reduce the incidence of the classical form of bronchopulmonary dysplasia characterized by marked fibrosis and emphysema. However, a new form of bronchopulmonary dysplasia marked by arrest of alveolarization remains a complication in the postnatal course of extremely low-birth-weight infants. To better understand this challenging complication, detailed alveolarization mechanisms should be delineated. Proper alveolarization involves the temporal and spatial coordination of a number of cells, mediators, and genes. Cross-talk between the mesenchyme and the epithelium through soluble and diffusible factors are key processes of alveolarization. Lung interstitial cells derived from the mesenchyme play a crucial role in alveolarization. Peak alveolar formation coincides with intense lung interstitial cell proliferation. Myofibroblasts are essential for secondary septation, a critical process of alveolarization, and localize to the front lines of alveologenesis. The differentiation and migration of myofibroblasts are strictly controlled by various mediators and genes. Disruption of this finely controlled mechanism leads to abnormal alveolarization. Since arrest in alveolarization is a hallmark of a new form of bronchopulmonary dysplasia, knowledge regarding the role of lung interstitial cells during alveolarization and their control mechanism will enable us to find more specific therapeutic strategies for bronchopulmonary dysplasia. In this review, the role of lung interstitial cells during alveolarization and control mechanisms of their differentiation and migration will be discussed.

• KIEAE Journal
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• v.4 no.2
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• pp.65-72
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• 2004

Ecological architecture enables people to recycle and reuse architectural resources within the category of ecosystem and also to minimize the effect on environment in a whole process, including architectural planning, usage and exhaustion to use sustainable energies. Rammed earth wall construction method utilized in EcoCenter located in Crystalwaters ecological village in Austrailia is a good example, which maximizes its advantages and also covers its limits to use soil and wood as structural resources. In a case of wood, they used non-treated timber to minimize environmental load and utilized used materials in openings. In the roofs, aluminum coated steel which is plated with zinc collects rain effectively even though it is not regenerable. Nontoxic finishes and insulation in floor and ceiling with used papers are able to minimize its environmental load. Solar energy system applied in EcoCenter enables them to market extra energy with electricity companies as well as support needs of its own buildings to utilize photovoltaic panel system with PV panels. Passive solar system is planned effectively in heating and cooling to apply regenerative walls in a use of rammed earth wall construction and natural ventilation systems through openings.

• Journal of the Korean Solar Energy Society
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• v.30 no.6
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• pp.89-94
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• 2010

A large portion of the energy cost of a building is cooling and heating to maintain a comfortable indoor environment. Air conditioning is now one of the important parts in the building design, as increase in energy consumption and pollutant emission in energy conversion process. In this study, elements that affects the energy consumption of model building are identified and the perfomance analysis of the alternative a Low Energy Cooling Systems considering characteristics of model building and energy saving performance is analyzed. In this study, elements that affect the energy consumption of office building are identified and energy saving performance of the alternative air conditioning system is analyzed. As a result, applied to earn and suggest basic data for energy saving measures. In this study, EnergyPlus simulation program was used to evaluate the energy load when alternative Low Energy Cooling Systems are applied to the model building. The reliability of simulation program is verified by comparing actual energy load from operation data of building management office and predicted energy load using simulation program. For Low Energy Cooling System application which considers the purpose and characteristics of the building, reasonable and energy-saving air conditioning method obtained by analyzing energy consumption elements for each expected air conditioning methods is used to deduct result of this study.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.1
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• pp.60-67
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• 2007

The purpose of this study is to evaluate indoor air quality at the stage of building construction. To check the IAQ at the stage of construction IAQX simulation program developed by EPA was used and the values of TVOC were analyzed with time-series. The Simulation conditions are as follows. 1) Ventilation rate, 2) Time schedule of works, 3) Material change. Through this simulation, the major factors which affect the IAQ were analyzed and the importance of empirical data about the time-series emission rate of concerned material could be confirmed.