• 한국안전학회지
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• 제23권2호
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• pp.1-6
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• 2008

The present study investigates on improvement of inhalation efficiency of hood in ventilation system for elimination of industrial dust. The hood, one of local exhaust ventilation system, has an important function to inhale a pollution source such as harmful dust and industrial waste. In this study, in order to improve the inhalation efficiency of the industrial hood, a new device named "gas-guide-device" was attached to inside of hood. The thermal fluid commercial code "Phoenics ver 3.1" was used to analyze the flow velocity distribution at the hood inlet and around the hood after gas-guide-device was installed. And the flow velocity on each position inside and around the hood was actually measured using the hot wire type anemometer under the same condition as that of numerical analysis. Also, in order to identify the optimum shape of gas-guide-device, numerical analysis and experiments are performed under various conditions and their results are presented. The results of this study revealed that the hood attached with gas-guide-device was higher the inhalation efficiency than that for without one and can be possible to improve the capture velocity of the industrial dust. And the optimum shape of gas-guide-device was identified that the ratio of two sizes of gas-guide-device, X to Y, has 4 to 6 on the basis of the hood size in use and the width (b) of gas-guide-device.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 추계학술발표대회 논문집
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• pp.279-284
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• 2009

Traditionally, so-called "industrial waste gases", such ad exhaust from boilers at industrial installations and a large quantity of soot discharged from power station, before their release into the atmosphere, have been on occasion subjected to an air cleaning process to remove fine particles that may pollute the atmosphere (such as mist and dust containing various powdery or oily substances and moisture from industrial waste gases). The release of industrial waste gases containing these particles directly into the atmosphere poses a serious threat to the earth environment; and recovery of these noxious substances is required by law in some countries and local governments. in urban areas, air pollution from automobile exhaust and others creates a serious condition. Some homes are equipped with and use indoor air purifiers. In many of the kitchens of restaurants, smoke generated during cooking and otherwise contaminated air are cleansed by air purifiers before being released outside or recycled inside. For the dust collecting devices to recover the fine particles contained in contaminated air, the cause for air pollution and how to purify air, many types based on various principles are known. Specifically, classified based on theories of particle collection, filtration, gravity, inertia, centrifugation, electricity, and cleaning types are cited as available processes. Among them, an appropriate type is selected according to the size or type of fine particles to be collected and conditions for installation. For the efficiency of dust collection, a filtration system (by using bag filters and others) and electric system are particularly outstanding and are therefore used widely in various areas of industry. In this research, rotary type high performance oil mist and smoke collecting system with self auto cleaning device equipped with the cleaning fluid spraying section is investigated.

• 한국산업보건학회지
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• 제16권2호
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• pp.91-100
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• 2006

The purpose of this study was to validate alternative method by using non-carcinogenic, and less toxic solvents than NIOSH analytical method 5524 for measuring the airborne MWFs in workplaces. In laboratory tests, the ETM solvents(mixture of same volume for ethyl ether, toluene, and ethanol) were selected. The alternative method of analyzing MWFs, referred to as the ETM solvent extraction method, showed 0.04 mg/sample as LOD, and 0.15 mg/sample as LOQ. The analytical precision (pooled CV, coefficient of variation) of the ETM solvent extraction method for analyzing the straight, soluble, semisynthetic, and synthetic metalworking fluid was 1.5%, 2.0%, 2.6%, 1.6%, respectively, which was similar to the precision (2.6%) of NIOSH analytical method (NIOSH 0500) for total dust. The analytical accuracy by recovery test, spiked mass calculated as extractable mass, was almost 100%. As the result of storage stability test, metalworking fluid samples should be stored in refrigerated condition, and be analyzed in two weeks after sampling. The 95% confidence limit of the estimated total standard error for the ETM solvent extraction method for analyzing the straight, soluble, semisynthetic, and synthetic metalworking fluid was ${\pm}12.6%$, ${\pm}12.5%$, ${\pm}14.0%$, and ${\pm}13.6%$, respectively, which satisfied the OSHA sampling and analytical criteria.

• Asian Journal of Atmospheric Environment
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• 제4권3호
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• pp.141-149
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• 2010

Aerosol size and number concentration were observed in the atmospheric boundary layer over Beijing (from near the ground to 1,200 m) on March 15 (a clear day) and 16 (a dusty day), 2005. The results were further compared with lidar measurements in order to understand the dependency of extinction on the particle size distribution and their vertical changes. The boundary layer atmosphere was composed of several sub-layers, and a dry air layer appeared between 400 and 1,000 m under the influence of dust event. In this dry air layer, the concentration of the fine-mode particles (diameter smaller than $1.0\;{\mu}m$) was slightly lower than the value on the clear day, while the concentration of coarse-mode particles (diameter larger than $1.0\;{\mu}m$) was remarkably higher than that on the clear day. This situation was attributed to the inflow of an air mass containing large amounts of Asian dust particles and a smaller amount of fine-mode particles. The results strongly suggest that the fine-mode particles affect light extinction even in the dusty atmosphere. However, quantitatively the relation between extinction and particle concentration is not satisfied under the dusty atmospheric conditions since laser beam attenuates in the atmosphere with high concentration of particles. Laser beam attenuation effect becomes larger in the relation between extinction and coarse particle content comparing the relation between extinction and fine particle content. To clarify this problem technically, future in situ measurements such as balloon-borne lidar are suggested. Here extinction was measured at 532 nm wavelength. Measurements of extinction at other wavelengths are desired in the future.

• 한국임상수의학회지
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• 제20권4호
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• pp.496-500
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• 2003

A one-year-old male Japanese Chin with anorexia, retching, dyspnea and continuous coughing was brought to the Veterinary Teaching Hospital, Chungbuk National University. Chest radiographs showed moderate regional alveolar pattern with mild interstitial patterns in the caudo-dorsal lung fields and the ill-defined mass in the perihilar area which is consistent with perihilar lymphadenopathy. Although the dog showed severe eosinophilia in the complete blood count, the serum profile values were within normal ranges. There was no indication of any parasite infestation in the direct and floatation examination of feces, skin scraping test and heartworm examination. There was no growth of bacteria and fungi in the selected media such as Mueller Hinton broth, Sabouraud Dextrose agar and Potato Dextorse agar, which were inoculated with tracheal fluid collected using endotracheal tube and cultured for 3 days. In the tracheal fluid smear, most prominent cells were eosinophils, which are a almost 80% of total cells and other cells such as leukocytes, neutrophils and ciliated colummar cells were also observed. Any parasite was also not detected in its smear. Prednisolone (PDS; 1 mg/kg, BID SC), aminophylline (10 mg/kg, TID IV) and nebulization with gentamicin (50 mg) plus saline (3 ml) were given for 1 week. At 3rd day of treatment, blood eosinophil value was return to normal range and pulmonary condition was also improved. The allergen test with serum performed during therapy was positive in the 19 index including milk, barley, tomato pomace, catfish, bonito, house dust and wool, and borderline in 10 index including wheat, house dust mites and house fly. The patient is responding well to PDS therapy. Based on these findings, a possible diagnosis of pulmonary infiltration with eosinophils was made in this dog.

• 방사성폐기물학회지
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• 제3권1호
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• pp.9-16
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• 2005

To evaluate parameters influencing on the dust removal of the High Temperature Filter(HTF) system, a computer simulation of fluid dynamics inside the system had been performed. The results showed that the optimum pulse jet periods were 50ms and 90ms for the 1000mm and 1500mm long filter elements respectively. Dust removal effect was very excellent under the pulse jet pressure of 3 bar. But the distance between the pulse jet nozzle and the venturi of a filter element had no meaningful effect on the performance with the variation from 5mm to 10mm. Compared to the dispersion mode of pulse jet, the collective mode of pulse jet flow was preferable in maintaining the pressure inside the system stable.

• 에너지공학
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• 제24권3호
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• pp.122-127
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• 2015

본 연구에서는 클린룸에서의 3차원 유동해석을 수행하였다. 로봇실험 장치에서 로봇의 움직임에 의해 형성되는 유동장에 대한 수치적인 분석을 본 연구에서는 다루고 있으며, 클린룸에서 로봇의 움직임에 대한 영향을 분진이 쌓이는 영역을 찾기 위해서 진행된다. 다관절 로봇의 움직임에 의해 생성되는 바닥 표면의 분진은 유동장 분석에 의해 예측될 수 있으며, 해석결과는 커다란 스월유동이 움직이는 로봇 주위에서 생성된다고 분석된다. 따라서, 가장 바람직한 유동 조건은 공기의 입구와 출구부의 위치를 다시 정하여 유동속도를 변화시키면서 검토해야 한다.

• 한국농공학회논문집
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• 제61권2호
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• pp.85-95
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• 2019

The internal environment in pig house is closely related to the animal productivity. In addition, it is important to consider a working environment inside the pig house due to high gas and dust concentrations. The poor working environment inside the pig house can cause health problems including respiratory diseases. To analyze the working environment, it is important to evaluate the ventilation efficiency to effectively remove harmful gases and dust. The purpose of this study is to develop a 3D CFD model to analyze the working environment in the pig house. CFD model was validated by comparing air temperature distributions between CFD computed and field measured data. The average air flow rate at the pig height was 40.1 % lower than the working height when incoming air was concentrated on upper layer by the installed ventilation system on the experimental pig house. Using the validated CFD model, the regional ventilation efficiency was computed by the TGD(tracer gas decay) method at the pig and working heights. There was a difference of ventilation efficiency on 14 % between the air stagnated section and the rest sections. Stagnated gas concentration can be effected by animal and human health.

• 한국입자에어로졸학회지
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• 제19권2호
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• pp.43-53
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• 2023

In this study, the ventilation system of the enclosed conveyor belt for coal transportation was evaluated, and the particle removal efficiency according to the ventilation conditions was identified using computational fluid dynamics and particle behavior analysis. The most effective way to remove dust generated inside the closed conveyor belt is to adjust the position of the exhaust port of the duct so that the air is exhausted around the rear of the conveyor belt. And this method seems to work for another narrow and long spaces where air enters in one direction. In addition, when the air flow rate of the each duct was less than 300 CMM, it was efficient to increase the flow rate of the duct located at the rear of the conveyor belt, and when the flow rate of the each duct was higher than 300 CMM, it was efficient to increase the flow rate of the duct located at the front of the conveyor belt.

• 한국입자에어로졸학회지
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• 제12권3호
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• pp.51-56
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• 2016

Due to recent development in nanotechnology and increasing usage and production of nanomaterials, numerous studies related to environment, sanitation and safety handling of nanoparticle are being conducted. Since nanoparticles can be easily absorbed into human bodies through breathing process, based on their toxic substances and their large specific surface, these particles can cause serious health damage. Therefore, to reduce nanoparticle emissions, nanofiltration technology is becoming a serious issue. Filtration is a separation process during which a fluid passes through a barrier by removing the particles from the stream. Barrier filters can be made of various materials and shapes. One of the most common type of barrier filter is the fibrous filter. Fibrous filters are divided in two types: nonwoven and woven fabrics. Polypropylene is a thermoplastic material, used as a base material for melt blown nonwoven fabric. In this study, we examined filtration property of KCl nanoparticles with a mean particle diameter of 75 nm using multilayer meltblown filter samples. These experiments verify that the penetration of nanoparticle in the filter correlate with pressure drop; the meltblown layer MB1 has the greatest effect on dust collection efficiency of the filter. Among all tested samples, dust collection efficiency of 2-layer filter was best. However, when considering the overall pressure drop and dust collection efficiency, the 4-layer filter has the highest quality factor for particles smaller than 70 nm.