• 한국항해항만학회지
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• 제34권3호
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• pp.189-194
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• 2010

최근 지구 환경 문제의 심각성이 대두되면서, 전과정 평가(Life Cycle Assessment)에 대한 선박 적용 연구가 조금씩 진행되고 있다. 본 논문에서는 선박 LCA 연구의 일환으로 선박 배기 가스 분석을 수행하였다. 이를 위하여 화물선에 대한 온실 배기 가스 배출 분석을 수행하였다. 대상 선박은 벌크선박과 유조선 등 2척을 모델로 삼았으며 과거 수년간의 실적 데이터를 분석하여 운항인벤토리 중 온실 배출가스의 정략적 데이터를 분석하였다. 이 분석을 통하여 화물선 운송 시 화물 1톤을 1마일 수송하는데 배출되는 배기 가스량의 분석을 시도하였다.

• 환경위생공학
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• 제4권2호
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• pp.91-99
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• 1989

An anaerobic acidogenic fermentation experiment was carried out in order to investigate the distribution of volatile acid products and gas generations with varing temperatures and pH values. The experiment was carried out using $1\%$ glucose as substrate and a pair of 3.5 liter vessle as bench scale batch reactors. The reactors were operated for 7 days at 25, 30 and $35^{\circ}C$ and at pH values of 4.0, 4.5, 5.0, 5.5 and 6.0 at each temperature conditions. Major products at all experiment pH's at $35^{\circ}C$ were acetic acids and butyric acids which together composed around $90^{\circ}F$ of total product acids. At higher pH values at $35^{\circ}C$, propionic acid reached around $10\%$. At all experiment conditions, 52 to $55\%$ of generated gases comprised of hydrogen gas and 45 to $48\%$ of carbon dioxide. With temperature increase from 25 to $35^{\circ}C$, the production rate of acetic acid increased 2.9 fold, butyric acid 22 fold, hydrogen gas 2.0 fold and carbon dioxide gas 2.3 fold. Optimum reaction conditions for highest production of acetic acid and hydrogen gas was determined to be pH 5.5 at $35^{\circ}C$.

• 대한임상독성학회지
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• 제6권2호
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• pp.99-103
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• 2008

Purpose: Chlorine gas is a common irritant that usually causes mild respiratory symptoms. One severe symptom, RADS (Reactive Airway Dysfunction Syndrome), is not well known to physicians. We analyzed the clinical features of chlorine gas exposure. Methods: We prospectively collected 25 cases of chlorine gas exposure near our emergency center on January 10th, 2007, and analyzed demographic data, event-to-ER interval, symptoms, and laboratory results based on medical records. Results: Only 2 patients out of 25 were admitted because of severe symptoms, the rest were discharged without complications. Sixty percent of them visited the ER within 12 h of exposure. The most common symptoms were chest discomfort (60%), headache (40%), nausea (40%), throat irritation (26%), and cough (32%). Two out of eight dyspnea cases showed abnormal pulmonary function, but only one case was diagnosed as RADS. Conclusion: Most symptoms after chlorine gas exposure can be treated conservatively. However, patients with chlorine exposure should be followed up long term for delayed complications.

• Nuclear Engineering and Technology
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• 제55권5호
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• pp.1775-1782
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• 2023

Several reactor physics commissioning experiments were conducted to obtain the neutronic parameters at the beginning of the G.A. Siwabessy Multi-purpose Reactor (RSG-GAS) operation. These parameters are essential for the reactor to safety operate. Leveraging the experimental data, this study evaluated the calculated core reactivity, control rod reactivity worth, integral control rod reactivity curve, and fuel reactivity. Calculations were carried out with Serpent 2 code using the latest neutron cross-section data ENDF/B-VIII.0. The criticality calculations were carried out for the RSG-GAS first core up to the third core configuration, which has been done experimentally during these commissioning periods. The excess reactivity for the second and third cores showed a difference of 510.97 pcm and 253.23 pcm to the experiment data. The calculated integral reactivity of the control rod has an error of less than 1.0% compared to the experimental data. The calculated fuel reactivity value is consistent with the measured data, with a maximum error of 2.12%. Therefore, it can be concluded that the RSG-GAS reactor core model is in good agreement to reproduce excess reactivity, control rod worth, and fuel element reactivity.

• 한국유체기계학회 논문집
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• 제12권1호
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• pp.16-21
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• 2009

In the last five years, 91 accidents from portable gas ranges and non-refillable metallic gas cartridges have occurred. The gas cylinder installed with a relief valve was developed to prevent an explosive accident from the gas cartridge. In this study it was carried out to evaluate the safety of a gas cylinder mounted with a relief valve which can prevent an explosion. Under the real using condition and the extreme condition the gas cylinder is heated with an electric heater. Simultaneously, the operating pressure is checked and the suitability of releasing flux is evaluated. And the possibility of fire or explosion was tested when the gas was released from the relief valve at the real using condition. Using a numerical simulation method, the diffusion of butane gas released from a relief valve was visualized.

• 신재생에너지
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• 제2권2호
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• pp.94-101
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• 2006

[ $1m^3$ ] solid hydrate contains up to $200m^3$ of natural gas, depending on pressure and temperature. Such large volume of natural gas hydrate can be utilized to store and transport large quantity of natural gas in a stable condition. So, in the present investigation, experiments carried out for the formation of natural gas hydrate governed by pressure, temperature, and gas compositions, etc.. The results show that the equilibrium pressure of structure II natural gas hydrate) is approximately 65% lower and the solubility is approximately three times higher than structure I methane hydrate). Also, the subcooling conditions of the structure I and II must be above 9K and 11K in order to form hydrate rapidly regardless of gas components, but the pressure increase is more advantageous than the temperature decrease in order to increase the gas consumption. And utilizing nozzles for spraying water in the form of droplets into the natural gas dramatically reduces the hydrate formation time and increases its solubility at the same time.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.399-402
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• 2006

[ $1m^3$ ] solid hydrate contains up to $200m^3$ of natural gas, depending on pressure and temperature. Such large volume of natural gas hydrate can be utilized to store and transport large quantity of natural gas in a stable condition. So, in the present investigation, experiments carried out for the formation of natural gas hydrate governed by pressure, temperature, and gas compositions, etc.. The results show that the equilibrium pressure of structure II natural gas hydrate (is approximately 65% lower and the solubility is approximately three times higher than structure I methane hydrate). Also, the subcooling conditions of the structure I and II must be above 9K and 11K in order to form hydrate rapidly regardless of gas components, but the pressure increase is more advantageous than the temperature decrease in order to increase the gas consumption. And utilizing nozzles for spraying water in the form of droplets into the natural gas dramatically reduces the hydrate formation time and increases its solubility at the same time.

• 센서학회지
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• 제32권2호
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• pp.105-109
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• 2023

In this study, we present a power-efficient driving method for gas sensor systems based on the analysis of input signal characteristics. The analysis of the gas sensor output signal characteristics in the frequency domain shows that most of the signal portions are distributed in a relatively low frequency region when extracting the gas sensor signal, which can lead to further performance improvement of the gas sensor system. Therefore, the proposed gas signal extracting technique changes the operating frequency of the read-out circuit based on the frequency characteristics of the output signal of the gas sensor, resulting in a reduction of power consumption at the whole system level. The proposed sensing technique, which can be applied to a general-purpose commercial gas sensor system, was implemented in a printed circuit board (PCB) to verify its effectiveness at the commercial level.

• 한국수소및신에너지학회논문집
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• 제25권3호
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• pp.247-254
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• 2014

The synthesis of Fischer-Tropsch oil is the catalytic hydrogenation of CO to give a range of products, which can be used for the production of high-quality diesel fuel, gasoline and linear chemicals. Our cobalt based catalyst was prepared Co/alumina, silica and titania by the incipient wet impregnation of the nitrates of cobalt and promoter with supports. Cobalt catalysts was calcined at $350^{\circ}C$ before being loaded into the FT reactors. After the reduction of catalyst has been carried out under $450^{\circ}C$ for 24hrs, FT reaction of the catalyst has been carried out at GHSV of 4,000/hr under $200^{\circ}C$ and 20atm. From these test results, we have obtained the results as following ; in case of 12wt% Co-supported $Al_2O_3$, $SiO_2$ and $TiO_2$ catalysts, maximum activities of the catalysts were appeared at the promoters of Mn, Mo and Ce respectively. The activity of 12wt% $Co/Al_2O_3$ added a Mn promoter was about 3 times as high as that of 12wt% $Co/Al_2O_3$ catalyst without promoters. When it has been the experiment at the range of reaction temperature of $200{\sim}220^{\circ}C$ and GHSV of 1,546~5,000/hr, the results have shown generally increasing the activities with the increase of reaction temperature and GHSV.

• 한국가스학회지
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• 제13권3호
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• pp.22-27
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• 2009

이 논문은 한국가스안전공사가 도시가스 고압배관에 대한 안전성평가를 실시하고 안전관리 조치를 권고하는 경우 그 안전관리조치가 합리적으로 실행가능한 것인지를 판단하기 위한 비용.편익분석 방법으로 PF(Proportion Factor)를 사용할 것을 제시하였다. 또한, 설치 예정인 도시가스 고압배관에 대하여 정량적 위험성평가를 실시하고, 평가결과에 따라 개선 권고한 안전조치에 대하여 VPF와 PF를 이용한 비용 편익분석을 실시하여 제시한 위험감소조치가 합리적으로 실행가능한 것임을 확인할 수 있었다. 본 논문에서 제시한 비용 편익분석방법은 국내에서 안전성평가를 실시하고 위험감소조치를 제시하는 경우 그 조치가 합리적으로 실행 가능한 것인지를 입증하는데 유용하게 활용될 수 있을 것으로 판단된다.