• Journal of Korean Society for Atmospheric Environment
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• v.30 no.1
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• pp.26-36
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• 2014

The uncertainty assessment is important to improve the reliability of emission inventory data. The DARS (Data Attribute Rating System) have recommended as the uncertainty assessment technic of emission inventory by U.S. EPA (Environmental Protection Agency) EIIP (Emission Inventory Improvement Program). The DARS score is based on the perceived quality of the emission factor and activity data. Scores are assigned to four attributes; measurement/method, source specificity, spatial congruity and temporal congruity. The resulting emission factor and activity rate scores are combined to arrive at an overall confidence rating for the inventory. So DARS is believed to be a useful tool and may provide more information about inventories than the usual qualitative grading procedures (e.g. A through E). In this study, the uncertainty assessment for 2009 CAPSS (Clean Air Policy Support System) emission inventory is conducted by DARS. According to the result of this uncertainty assessment, the uncertainty for fugitive dust emission data is higher than other sources, the uncertainty of emission factor for surface coating is the highest value, and the uncertainty of activity data for motor cycle is the highest value. Also it is analysed that the improvement of uncertainty for activity data is as much important as the improvement for emission factor to upgrade the reliability of CAPSS emission inventory.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.4
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• pp.571-578
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• 2004

The purpose of this study is to estimate of emission factors of the air pollutants for the melting furnaces for the iron and steel industry. The result of this study is able to obtaine the emission factor of particulate matters (PM), sulfur dioxide. nitrogen oxides for melting furnace. The emission factors of each pollutants were as follows : - the emission factor varied between 6.13E-03~6.12E-01 kg/ton for PM -1.59E-01~2.45E+00kg/ton for $SO_2$ - 6.82E-02~6.88E-01 kg/ton for NOx, respectively. Analysis of the differences in the emission factors of ours and U.S. EPA's yielded the following results for the Wilcoxon method : p>0.05. The statistical analysis showed no differences in the our emission factors and U.S. EPA's

• Journal of Environmental Science International
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• v.21 no.6
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• pp.713-724
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• 2012

Emission rates of biogenic hydrocarbon emitted from broad-leaved trees grown at Jeju Island were estimated using a dynamic enclosure method. Leaf temperature, PAR and relative humidity were monitored during the sampling time. The emission rates of isoprene and monoterpene were measured for five plants(Carpinus laxiflora, Quercus serrata, Styrax japonicus, Quercus acutissima, Quercus crispula) during the sampling period at the Halla mountain sites. Among five tree species, the highest isoprene emission rate of 10.60 ${\mu}g\;gdw^{-1}hr^{-1}$ was observed for Quercus serrata. The seasonal emission rates were the highest during summer and the emission of isoprene was highly affected by light and temperature variations. The highest emission rate of isoprene was occurred between 13:00 and 14:00, but isoprene was not emitted in nighttime because of the absence of light.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.6
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• pp.562-572
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• 2015

$NO_x$ emissions from diesel vehicles have been regarded as a main cause of high $NO_2$ concentration in metropolitan area. Recent studies have shown that the on-road $NO_x$ emissions of diesel vehicles are quite higher than the emission limits specified with the pre-defined test method for emission certification. To reduce air pollutants effectively, the discrepancy of emissions in certification and real-driving conditions should be tackled. In this study, the real-driving emissions have been estimated with portable emission measurement system (PEMS). The results of this study have shown that the on-road $NO_x$ emissions from diesel vehicles have been decreased as the introduction of stricter emission regulation, EURO-6, but additional reduction should be still required and robust technologies should be applied to control $NO_x$ in real-driving conditions. RDE-LDV (Real Driving Emission - Light Duty Vehicles) test method being developed in the European Union can represent excessive on-road $NO_x$ emissions of diesel vehicles as applied emission technologies and can be a solution to remove discrepant $NO_x$ emissions between certification and Korean real-driving conditions. Among the $NO_x$ reduction technologies for EURO-6 diesel vehicles, selective catalytic reduction (SCR) system has shown the better performance than lean $NO_x$ trap (LNT) system to control on-road $NO_x$ emissions. Implementing RDE-LDV will require vehicle manufacturers to adopt the more effective $NO_x$ reduction technology in real driving conditions.

• Journal of the korean Society of Automotive Engineers
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• v.15 no.4
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• pp.44-58
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• 1993

• Journal of Power System Engineering
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• v.21 no.6
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• pp.94-100
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• 2017

Due to the environmental problems caused by the greenhouse effect, regulation of $CO_2$ emissions is getting stronger day by day. In paricular, regulations of automobiles $CO_2$ emissions are being strengthen. However, existing $CO_2$ measurement methods do not reflect the environment and operating conditions on actual roads. Emissions of $CO_2$ can be increased by various conditions such as environmental condition(temperature and humidity) and driver's tendency(aggressive and passive). Therefore it is necessary to reflect the conditions of various actual roads such as 5-cycle test method on behalf of the existing $CO_2$ emission measurement method. The 5-cycle measurement method has five test modes; FTP-75, HWFET, US06, SC03, Cold FTP-75. The method reflects the following three environments and operating conditions as compared to conventional method; Using heater at low temperature, Aggressive driving such as rapid acceleration or deceleration, Using air conditioner at high temperature. Because of these various conditions of each test cycle, the 5-cycle method can reflect actual environments and operating conditions. This paper attempt to analyze $CO_2$ emission characteristics based on the results measured through the 5-cycle mode and develop the correction formula that can derive the results of the 5-cycle test method using existing test methods. As a result, the developed correction formula is expected to reduce $CO_2$ emissions and cut down expense for testing 5-cycle mode.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.5
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• pp.488-496
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• 2003

To establish nondestructive test method for rocket motor assembly with rubber and aerospace composite materials, practicable quality control acoustic emission test method is presented. Structural analysis for motor assembly is performed by ABAQUS code and analysis output result is confirmed by strain gage and AE data. Various specimens were tested and analyzed using strain gage and acoustic emission data. The hit rate of acoustic emission was closely related with case/rubber debonding. This report also describes practicable acoustic emission nondestructive method for evaluating motor case assembly quality assurance in the industrial field.

• Transactions of Materials Processing
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• v.29 no.1
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• pp.20-26
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• 2020

In the design of the metal forming processes, various types of ductile fracture criteria are used to predict crack initiation and to fabricate metallic products without any defects. However, the quantitative measurement method for determination of crack initiation is insufficient. It is very difficult to detect crack initiation in ductile metals with excellent deformability because no significant load drop is observed due to crack generation. In this study, the applicability of acoustic emission sensors, which are commonly used in facility diagnostics, to measure crack initiation during the metal forming process was analyzed. Cylindrical notch specimens were designed using the finite element method to induce a premature crack on the surface of pre heat-treated steel (ESW90) material. In addition, specimens with various notch angles and heights were prepared and compression tests were carried out. During the compression tests, acoustic emission signal on the dies and images of the surface of the notch specimen were recorded using an optical camera in real time. The experimental results revealed that the acoustic emission sensor can be used to detect crack initiation in ductile metals due to severe plastic deformation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.611-615
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• 2004

In recent, there have been several developments in lamp technology that promise savings in electrical power consumption and improved quality of the lighting space. Above all, Electrodeless fluorescent lamp is the removal of internal electrodes and heating filaments that are a light-limiting factor of conventional fluorescent lamps. The electrodeless fluorescent lamp is intended as a high efficacy replacement for the incandescent reflector lamp in many applications. Therefore, the electrodeless fluorescent lamps is substantially higher than that of conventional fluorescent lamps and last up to 60,000 hours. In this paper, electron temperature and electron density were measured in a radio-frequency inductively coupled plasma using a Langmuir probe method for emission characteristics. Measurement was conducted in an argon discharge for pressure from 10 [mTorr] and input RF power 100 [W] to 150 [W]. As for the electron density, a electron temperature was more distinguished for a emission characteristic. The results of ideal may contribute to systematic understanding of a electrodeless fluorescent lamps of emission characteristics.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.32-32
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• 2011

Plasma etching is used in microelectronic processing for patterning of micro- and nano-scale devices. Commonly, optical emission spectroscopy (OES) is widely used for real-time endpoint detection for plasma etching. However, if the viewport for optical-emission monitoring becomes blurred by polymer film due to prolonged use of the etching system, optical-emission monitoring becomes impossible. In addition, when the exposed area ratio on the wafer is small, changes in the optical emission are so slight that it is almost impossible to detect the endpoint of etching. For this reason, as a simple method of detecting variations in plasma without contamination of the reaction chamber at low cost, a method of measuring plasma impedance is being examined. The object in this research is to investigate the suitability of using plasma impedance monitoring (PIM) with statistical approach for real-time endpoint detection of $SiO_2$ etching. The endpoint was determined by impedance signal variation from I-V monitor (VI probe). However, the signal variation at the endpoint is too weak to determine endpoint when $SiO_2$ film on Si wafer is etched by fluorocarbon plasma on inductive coupled plasma (ICP) etcher. Therefore, modified principal component analysis (mPCA) is applied to them for increasing sensitivity. For verifying this method, detected endpoint from impedance analysis is compared with optical emission spectroscopy (OES). From impedance data, we tried to analyze physical properties of plasma, and real-time endpoint detection can be achieved.