• Applied Chemistry for Engineering
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• v.28 no.3
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• pp.345-350
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• 2017

The sintered density of uranium oxide pellets for pressurized water reactors is generally analyzed with pellet's samples completed with the sintering process. In this paper, the sintered density was analyzed by the newly developed method measuring the chromatography of ammonium diuranate, a precursor of uranium oxide, by a spectrophotometer (CM-5, Konica Minolta) before completing the sintering process. As a result of the sintered density analysis based on the brightness, color coordinate values (L, a, b) obtained from five ammonium diuranate samples by a spectrophotometer and the trend line of sintered density analyzed by a previous method, the sintered density with respect to the L value was observed with 0.9967 of the decision factor $R^2$. In case of a value, $R^2$ value was 0.9534 indicating lower reliability than that of the L value. However, b value with $R^2$ value of 0.4349 showed a very low correlation.

• Fire Science and Engineering
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• v.24 no.5
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• pp.32-38
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• 2010

Multi-dimensional fire dynamics were studied numerically with the change in ventilation conditions in a full-scale ISO 9705 room. Fire Dynamic Simulator (FDS) was used for the identical conditions conducted in previous experiments. Flow rate and doorway width were changed to create over-ventilated fire (OVF) and under-ventilated fire (UVF). From the numerical simulation, it was found that the internal flow pattern rotated in the opposite direction for the UVF relative to the OVF so that a portion of products recirculated to the inside of compartment. Significant change in flow pattern with ventilation conditions may affect changes in the complex process of CO and soot formation inside the compartment due to increase in the residence time of high-temperature products. The fire behavior in the UVF created complex 3D characteristics of species distribution as well as thermal and flow structures. In particular, additional burning near the side wall inside the compartment significantly affected the flow pattern and CO production. The distribution of CO inside the compartment was explained with 3D $O_2$ distribution and flow patterns. It was observed that gas sampling at local positions in the upper layer were insufficient to completely characterize the internal structure of the compartment fire.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.1
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• pp.108-117
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• 2016

In this paper, a portal system compatible with MRV regulation was designed to monitoring, reporting and verifying $CO_2$ emission and fuel consumption data from an international ship. A portal system supports monitoring and reporting task of international shipping companies and calculates national greenhouse gas inventory. EU MRV law, MRV discussions of IMO, responses of international shipping companies to ship energy efficiency and greenhouse gas regulation, and greenhouse gas statistics on international shipping were analyzed to drive portal system requirements. For ship energy efficiency and $CO_2$ emitted monitoring, a data collection module was designed based on on-board equipment, energy efficiency measuring device and navigation report. Data transfer module with easy management and minimized usage to transfer ship data to shore was designed. A portal system was designed to convert the collected data into the standard reporting format, perform monitoring, statical analysis, verification and auto report generation, and support national greenhouse gas inventory.

• Korean Journal of Environmental Agriculture
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• v.26 no.1
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• pp.1-6
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• 2007

In view of energy supply, biogas can be seen as alternative fuel by substituting considerable amount of fossil fuel and may be utilized for heat and power production or for transport fuel production ($CH_4-enriched$ biogas). The aim of this research is to analyse the emission of $NO_x$ and CO from biogas fired combustion engine for electric power production. The result indicate a significant effect of biogas composition ($CH_4-CO_2$ ratio) and biogas flow rate on the air pollutants emission. The emission factors from this study were compared with those of U.S. EPA. Low $CH_4-CO_2$ ratio condition typically shows the lower $NO_x$ and CO emission than higher $CH_4-CO_2$ ratio condition. At normal $CH_4-CO_2$ ratio (7:3) emission factors of $NO_x$ and CO were 1.29 and 30.43 g/MMBtu, respectively. At low $CH_4-CO_2$, ratio (6:4) emission factors of $NO_x$ and CO were 0.646 and 60.86 g/MMBtu, respectively, It should be emphasized that the actual emission may vary considerably from these results due to operating conditions including torque load and engine speed.

• Fire Science and Engineering
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• v.26 no.2
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• pp.75-83
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• 2012

An experimental study was conducted to investigate the effects of change in heat release rate on unsteady fire characteristics of under-ventilated fire in a semi-closed compartment. A standard doorway width of the full-scale ISO 9705 room was modified to 0.1 m and the flow rate of heptane fuel was increased linearly with time using a spray nozzle located at the center of enclosure. Temperature, heat flux, species concentrations and heat release rate were continuously measured and then global equivalence ratio (GER) concept was adopted to represent the unsteady thermal and chemical characteristics inside the compartment. It was observed that there was a significant difference in unsteady behavior between global and local combustion efficiency, and the GERs predicted by ideal and measured heat release rate were also shown different results in time. The unsteady behaviors of temperature, heat flux and species concentrations were represented well using the GER concept. It was important to note that CO concentration was gradually decreased with the increase in GER after reaching its maximum value in the range of 2.0~3.0 of global equivalence ratio. In addition, the experimental data on unsteady thermal and chemical behaviors obtained in a semi-closed compartment will be usefully used to validate a realistic fire simulation.

• Fire Science and Engineering
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• v.26 no.3
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• pp.21-28
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• 2012

The objective of this study is to evaluate the prediction accuracy of FDS(Fire Dynamic Simulator) for the thermal and chemical characteristics of under-ventilated fire with unsteady fire growth in a semi-closed compartment. To this end, a standard doorway width of the full-scale ISO 9705 room was modified to 0.1 m and the flow rate of heptane fuel was increased linearly with time (until maximum 2.0 MW based on ideal heat release rate) using a spray nozzle located at the center of enclosure. To verify the capability of FDS, the predicted results were compared with a previous experimental data under the identical fire conditions. It was observed that with an appropriate grid system, the numerically predicted temperature and heat flux inside the compartment showed reasonable agreement with the experimental data. On the other hand, there were considerable limitations to predict accurately the unsteady behaviors of CO and $CO_2$ concentration under the condition of continuous fire growth. These results leaded to a discrepancy between the present evaluation of FDS and the previous evaluation conducted for steady-state under-ventilated fires. It was important to note that the prediction of transient CO production characteristics using FDS was approached carefully for the under-ventilated fire in a semi-closed compartment.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.4
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• pp.301-307
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• 2005

The morphology of the high burnup $UO_2$ spent fuel, which was oxidized and annealed in a PIA (Post Irradiation Annealing) apparatus, has been observed. The high burnup fuel irradiated in Ulchin Unit 2, average rod burnup 57,000 MWd/tU, was transported to the KAERI's PIEF. The test specimen was used with about 200 mg of the spent $UO_2$ fuel fragment of the local burnup 65,000 MWd/tU. This specimen was annealed at $1400^{\circ}C$ for 4hrs after the oxidation for 3hrs to grain boundary using the PIA apparatus in a hot-cell. In order to oxidize the grain boundary, the oxidation temperature increased up to $500^{\circ}C$ and held for 3hrs in the mixed gas (60 ml He and 100 ml STD-air) atmosphere. The amount of 85Kr during the whole test process was measured to know the fission gas release behavior using the online system of a beta counter and a gamma counter. The detailed micro-structure was observed by a SEM to confirm the change of the fuel morphology after this test. As the annealing temperature increased, the fission products were observed to move to the grain surface and grain boundary of the $UO_2$ matrix. This specimen was re-structured through the reduction process, and the grain sizes were distributed from 5 to $10\;{\mu}m$.

• Analytical Science and Technology
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• v.17 no.3
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• pp.263-270
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• 2004

A method is described for the analysis of short-chain alkylphenol ethoxylates (APEOs), 4-octylphenol-di-ethoxylate (OP2EO) and 4-nonylphenol-di-ethoxylate (NP2EO), in drinking water or wastewater using reversed phase high-performance liquid chromatography with electrospray ionization mass spectrometry. The solvent system was water and methanol containing $10{\mu}M$ trifluoroacetic acid as an ionization solvent. We acidified 1 L of water samples to less than pH 2 with concentrated $H_2SO_4$ and loaded onto Sep-Pak $C_{18}$, and eluted with acetone. The calibration of OP2EO and NP2EO was performed for the concentration range from 20 to 500 ng/L and the correlation coefficients were 0.999 and 0.990, respectively. The limits of detection were 20 ng/L (OP2EO) and 50 ng/L (NP2EO) at a signal-to-noise ratio of 3. Accuracy and precision of this analytical method were 85.8 ~ 122.1% and 8.2 ~ 18.8%, respectively. The proposed method allowed a sensitive and rapid detection of OP2EO and NP2EO and it could be applied for monitoring of APEOs from environmental samples.

• Fire Science and Engineering
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• v.24 no.3
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• pp.131-138
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• 2010

Experimental and numerical studies were conducted to investigate the thermal and chemical characteristics of heptane fires in a full-scale ISO 9705 room. Representative fire conditions were considered for over-ventilated fire (OVF) and under-ventilated fire (UVF). Fuel flow rate and doorway width were changed to create OVF and UVF conditions. Detailed comparisons of temperature and species concentrations between experimental and numerical data were presented in order to validate the predictive performance of FDS (Fire Dynamic Simulator). The OVF and UVF were explicitly characterized with distributions of temperature and product formation measured in the upper layer, as well as combustion efficiency and global equivalence ratio. It was shown that the numerical results provided a quantitatively realistic prediction of the experimental results observed in the OVF conditions. For the UVF, the numerically predicted temperature showed reasonable agreement with the measured temperature. The predicted steady-state volume fractions of $O_2$, $CO_2$, CO and THC also agreed quantitatively with the experimental data. Although there were some limitations to predict accurately the transient behavior in terms of CO production/consumption in the UVF condition, it was concluded that the current FDS was very useful tool to predict the fire characteristics inside the compartment for the OVF and UVF.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.5 no.4
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• pp.83-93
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• 1994

1886년 고트리브 다이믈러와 칼 벤즈가 가솔린 자동차를 개발한 이후 100여년이 지난 지금 자동차는 비약적으로 진보, 발전하여 현대 산업사회와 개인의 생활에 있어 산업운송수단과 이동수단으 로서 필요불가결하게 되어 밀접한 관계를 갖고 있다. 우리나라 자동차 공업의 역사는 자동차가 사회적, 경제적 효용에 따라 그 생산과 보유대수가 날이 갈수록 증가 일로에 있으며, 자동차의 생산대수는 전세 계에서 년간 약 50,606천대('94년)로서 중요한 국가 기간 산업으로 자리하고 있다. 한편 전기, 전자공업의 발전에 따른 자동차의 Car Electronics가 많이 채용되게 됨에 따라 현재의 자 동차에는 대부분이 전자제어 System으로 구성되어 있다. 최근에는 Micro Processor를 이용한 전자부품이 많이 사용되어 전자파에 대한 문제가 다양하게 발생 하고 있다. 예를 들면 미국 캘리포니아주에서 전자점화제어장치와 연료분사 장치를 설치한 구미의 자동 차가 주행중 28MHz, 28W의 아마추어 무선을 탑제한 자동차가 통과할 때 엔진이 고르지 못한 보고가 있 었고, 화학섬유로된 옷을 착용한 전자부품이 다른 부품에 영향을 주는 사례가 맣아지고 있다. 따라서 자동차에는 여러가지의 전장품, 전자기기를 탑재하기 때문에 자동차 자체에서 발생하는 것과 외부로 부터 받는 전자장해 EMI(Electromagnetic Interference), EMS(Electromagnetic Susceptibility) 가 문제로 되어 자동차 및 부품 maker에 의한 EMC(Electromagnetic Compatibility) 평가의 중요성이 고조되고 있다. 차제무전기, 차제무전기, Car-Radio는잡음방해를 많이 받기도 하지만, 잡음원이 되기 도 한다. 또한 Engine 제어, 차속제어, Brake 제어등에 이용되는 전자제품은 방해에 의한 오동작 또는 파괴가 발생하여 주행기능, 안전성에 문제가 야기되지 않도록 해야 한다. 이러한 전자기 환경은 모두 RF(Radio Frequence)와 자동차에서의 전자파 장해 문제의 원이 될 수 있다. 자동차 및 그 부품의 전자기 방해에 관한 규격화는 1987년부터 괄목할 만하게 진행되어 이에 따른 규제 움직임이 IEC(International Electrotechnical Commission: 국제전기기술위원회) 산하의 하부기 구인 CISPR(International Special Committeeon Radio Interference: 국제 무선 장해 특별위원회)가 전자기 방해파에 대한 측정법 통일안을 제안 하였고, ISO(International Standardization Organiza- tion: 국제표준화 기구) 가운데 TC 22/SC3가 자동차의 전장품에 대한 장해를 논의히고 있다. 특히, 자동차의 EMC에 관한 국가 규격은 국제 규격에서 저술한 바와 같이 특별히 규정된 것이 없고 VDE(Verband Deutscher Elektrotechniker: 서독전기기술 협회)와 SAE(Society of Automotive Engi- neers: 자동차 기술자 협회)에서 비교적 활발하고 Jaso(Japanese Automobile Standards Organization: 일본 자동차 표준협회)에서 많이 진행중에 있다. 본 고에서는 자동차의 전자제어에 따른 잡음 발생 요인과 전자파 간섭 관련 자동차 규격과 시험평가 방법에 대해 간단히 소개 하였다.