• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.4
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• pp.410-418
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• 1999

This paper describes the use of residual and parameter identification methods for fault detection in an air handling unit. Faults can be detected by comparing expected condition with the measured faulty data using residuals. Faults can also be detected by examining unmeasurable parameter changes in a model of a controlled system using a system identification technique. In this study, AutoRegressive Moving Average with seXtrnal input(ARMAX) and AutoRegressive with eXternal input(ARX) models with both single-input/single-input and multi-input/single-input structures are examined. Model parameters are determined using the Kalman filter recursive identification method. Regression equations are calculated from normal experimental data and are used to compute expected operating variables. These approaches are tested using experimental data from a laboratory's variable-air-volume air-handling-unit.

• Asian Journal of Atmospheric Environment
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• v.9 no.1
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• pp.1-11
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• 2015

Increasing ozone concentrations are observed over Japan from year to year. One cause of high ozone concentration in the Kanto region, which includes areas inland from large coastal cities such as metropolitan Tokyo, is the transportation of precursors by sea breezes. However, high ozone concentrations are also observed in the morning, before sea breezes approach inland areas. In this point, there would be a possibility of residual ozone existing above the nocturnal boundary layer affects the ozone concentration in the following morning. In this study, we utilized the Weather Research and Forecasting model and the Community Multiscale Air Quality model to evaluate the effect of regional precursors and residual ozone on ozone concentrations over the inland Kanto region. The results show that precursors emitted from non-metropolitan areas affected inland ozone concentrations more than did precursors from metropolitan areas. Moreover, calculated results indicate downward transportation of residual ozone, resulting in increased concentration. The residual ozone was also affected by precursors emitted from non-metropolitan areas.

• Journal of Environmental Health Sciences
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• v.36 no.2
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• pp.77-81
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• 2010

Tobacco smoking and secondhand smoke exposure are linked to a number of adverse health outcomes. There is a new concept of thirdhand smoke that is residual tobacco smoke contamination remained after the cigarette is extinguished. This paper reviews published studies examining the residual tobacco smoke. Tobacco smoke can be attached to various surfaces and reemitted to air for long period of time. The dynamic process can allow thirdhand smoke exposure to tobacco smoke without direct exposure to secondhand smoke. One critical evidence of the thirdhand smoke exposure was significantly high urinary cotinine level of infant who did not have direct secondhand smoke exposure. Potential exposure to new and more potent chemicals generated from chemical reactions between residual tobacco smoke and ambient air pollutants can get more attention. Considering toxicity and exposure route, children are uniquely susceptible to thirdhand smoke exposure. The review provides strong background information for thirdhand smoke but warrant more researches on this issue.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.34 no.1
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• pp.14-17
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• 2024

Objectives: This is a case of air exposure assessment conducted after researchers complained of headaches and odor due to residual substances from fire extinguishing agents spread throughout the laboratory due to a malfunction of the fire extinguishing facility. Methods: A component analysis was conducted on the residual substances of a fire extinguishing agent spread in a laboratory using Py-GC-MS (pyrolysis gas chromatography mass spectrometry) at the research institute's own central equipment research center. As a result of the component analysis, several types of substances were detected. Among these, five types of substances subject to work environment measurement in the aromatic hydrocarbon series, which can affect headaches and odor, were selected as substances subject to exposure assessment in the air, and the measurement and analysis methods of the target substances were conducted in accordance with the KOSHA Guide for each substance. Conclusions: The measurement results showed that all 5 types of substances were not detected at locations A, B, and C. This is believed to be the result of the residual substances in the fire extinguishing agent being measured when approximately two months had elapsed after being exposed to the test bench, and the substances already exposed had volatilized and disappeared. In this survey, it is believed that the measurement process is more important than the measurement results.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.962-967
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• 2003

Recently, environmental pollution has become a serious problem in industry, and many researches have been done in order to preserve the environment. The coolant, which promotes lubrication, cooling and penetration, contains chlorine, sulfur and phosphorus to improve the machining efficiency. These additives, which move around into the air during machining, pollute working. Therefore, many researches on how to reduce the amount of coolant during machining have been carried out. However, to reduce even small amount of coolant causes high temperature of a workpiece and it brings thermal defects. In this study, the experiments of wet & dry grinding using cooling methods (using coolant only, mist and compressed cold air only) are performed to solve the problem of environmental contamination and to get a better surface integrity of a workpiece by comparing surface roughness, roundness and residual stress.

• The KSFM Journal of Fluid Machinery
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• v.12 no.4
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• pp.23-29
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• 2009

For the purpose of high outlet pressure, compactness and low vibration and noise, 2 stage reciprocating air compressors can have various cylinder arrangement: opposed, in-line, and V type. This paper presents an effective method to calculate the inertia forces and to design counter weight. This method is based on the complex representation for the orbital behavior of the compressor shaft. This method helps to find the optimal balancing rate easily to reduce the inertial force or moment. This paper shows that the residual inertia forces of the single throw shafts and the residual inertia moments of the double throw shafts remain to be imbalanced.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.9
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• pp.853-859
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• 2001

A pulsed tracer gas technique is applied to measure distributions of local mean age and residual life time of air in a half-scale experimental chamber. The room airflow patterns are flow-visualized by a Helium bubble generator for three different exhaust locations. A supply slot is located at the top of a right wall, and an exhaust slot is either at bottom-left(Case 1), bottom-right(Case 2), or top-left(Case 3) location. Results show that the distribution of LMA and LMR are different from each other, but both of them are closely related to the airflow pattern in the space. Results on overall room ventilation effectiveness are provided depending upon ventilation airflow rates for three different supply-exhaust configurations.

• Journal of Environmental Science International
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• v.22 no.9
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• pp.1105-1113
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• 2013

This paper attempted to estimate the emissions of HFC-134a from scrap truck as a result of measuring the residual quantities of HFC-134a in air conditioner of scrap truck. We measured the residual amounts in the scrap truck of 138 by applying commercial recover for refrigerants. The average residual rate(disposal-phase emission factor) is reported to be $44.3{\pm}3.3%$ within a confidence interval of 95%. Recent year model trucks exhibit the higher residual rates. Little variation, however, is observed in regard to vehicle size. The HFC-134a emission quantity from scrap truck in 2011 is estimated to be 55,908 $tCO_2$-eq that demonstrates 21.4% increase to compare with that in 2007. As the numbers of truck have increased dramatically during the last two decades, the emissions of HFC-134a from scrap truck would increase sharply in the next coming years. HFC-134a is a very high GWP greenhouse gas. therefore have to reduce the emissions from the scrap truck and need to find ways to recycle. The chemical compositions of refrigerants from scrap truck are quite similar to those of new refrigerants, suggesting that the refrigerants from scrap truck could be reused as refrigerant.

• The Korean Journal of Community Living Science
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• v.24 no.2
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• pp.187-194
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• 2013

The purpose of this study was to define the optimal boxthorn berries washing method for developing the boxthorn berries cleaner. We analyzed the rate of removal of residual pesticides according to washing methods; 1st - habitual washing method, 2nd - drum rotation washing method, 3th - drum rotation and air bubble washing method, 4th - drum rotation and nozzle spray washing method, 5th - drum rotation and air bubble and nozzle spray washing method. A rate of removal of residual pesticides of 88% was detected in the drum rotation and air bubble and nozzle spray washing method, and a rate of 82% was detected in the habitual washing method. The drum rotation and air bubble and nozzle spray washing method appeared to be the best good washing effect compared to the habitual washing method(about 6% compared to 82.0% higher). Clothianidin Triadimefon, Triforine ingredients, the drum rotation and air bubble and nozzle spray washing method efficiency was lower compared to the habitual washing method removal efficiency.

• Journal of Sensor Science and Technology
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• v.25 no.2
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• pp.116-123
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• 2016

This paper presents the fabrication and evaluation of the novel drag force type air flowmeter using MEMS technologies for the vehicle applications. To obtain the air drag force, the flowmeter utilized the curved beam structure, which was realized by the difference of residual stress between the silicon oxide layer and the silicon nitride layer. The paddle structure was applied for the maximum air drag force, and the dual-beam was adapted to prevent distortion. The basic experiments were performed in the wind tunnel, and the stable outputs were obtained. The device was applied to the internal combustion engine, and the results were compared with the HI-DS output where the convection thermal flowmeter was used as the reference sensor. The results indicated that the comparable resolutions and response times were obtained under the various engine speeds.