• 한국소음진동공학회논문집
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• 제14권11호
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• pp.1123-1128
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• 2004

An experimental study on firing noise of K2 rifle was performed. Firing noises of K2 rifle were measured at close distance to rifle. Firing noise of K2 rifle which made in Korea, has not measured before. The measurement of firing noise at close distance is not simple, because the amplitude of firing noise is much bigger than the measuring limit of ordinary sound level meter even though it uses a signal attenuator. The measurement of firing noise at close distance is necessary for noise source positioning and for obtaining the sound power of K2 rifle. By this experimental study, the firing noise levels of K2 rifle at different positions are obtained and these data can be used to Predict the sound pressure level at any distance from muzzle of the rifle. Also these data can be used to calculate the threshold shift of gunner's ear.

• KEPCO Journal on Electric Power and Energy
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• 제2권4호
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• pp.525-529
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• 2016

바이오매스 혼소는 신재생 에너지의 비중을 늘리면서 석탄화력발전에서의 $CO_2$ 배출을 저감할 수 있는 단중기적으로 가장 효과적인 방법이다. 본 논문에서는 이 중 기존 화력발전소에 가장 적은 초기투자비로 적용할 수 있는 직접 혼소법에 대하여 주로 고찰을 수행하고, 국내외 현황 및 전망에 대해 기술하였다. 직접 혼소법은 바이오매스 전용 미분기를 사용하여 혼소율을 늘리는 방법과 저 혼소율에서 초기투자비를 최소화하는 기존 석탄 미분기 사용 바이오매스 혼소법으로 나눌 수 있다. 유럽 및 미국에서는 혼소율을 높이기 위해 많은 상용발전소에서 바이오매스 전용 미분기를 사용하여 10~20% 가량의 혼소율(열량 기준)로 운전을 수행하고 있으나, 국내의 경우에는 RPS 대응을 위해 3~5% 가량의 혼소율에서 기존 석탄 미분기를 그대로 사용하여 바이오매스 혼소를 수행하고 있다. 신기후체제가 시작되고 석탄화력발전에서의 $CO_2$ 저감 요구가 점점 더 증대될 것으로 예상되는 바, 향후 바이오매스 고혼소율이 수행될 수 있는 기술적/저책적 방안이 모색되어야 하며, 이 경우 발생할 수 있는 설비에의 악영향을 면밀히 고려한 연료 표준화 및 전처리 기술이 개발되어야 한다.

• 대한치과기공학회지
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• 제30권1호
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• pp.33-39
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• 2008

Recently natural characteristics and esthetics have been interested increasing in clinical dentistry. Thus the evaluation of the shade of dental porcelain has become an important part in dental research. Noritake Super Porcelain EX-3 Vita shade A2 (Noritake, Japan) Vintage HaLo Vita shade A2 (Shofu, Japan), Vita omega 900 Vitapan 3D-master shade 2M2 (Vita, Germany) were conducted for six times for repeated firing in a way to observe the change of color with respect to the number of firing. The repeated firing was implemented with the vacuum firing and air firing, and by using Shade Eye-EX Chroma meter (Shofu, U.S.A.), the changes in values of shade, value and chroma were compared. With the above results, the change of color was not noticed only in Vita when repeated firing was applied.

• 한국연소학회지
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• 제19권3호
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• pp.8-17
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• 2014

The aims of this research were to evaluate effects of biomass co-firing to pulverized coal power plants and the variation of co-firing ratios on the plant efficiency related to power consumption of auxiliary system and flue gas characteristics such as production and component by process simulation based on the existing pulverized coal power plant. In this study, four kinds of biomass are selected as renewable fuel candidates for co-firing: wood pellet(WP), palm kernel shell(PKS), empty fruit bunch(EFB) and walnut shell(WS). Process simulation for various biomass fuels and co-firing ratios was performed using a commercial software. Gas side including combustion system and flue gas treatment system was considering with combination of water and steam side which contains turbines, condenser, feed water heaters and pumps. As a result, walnut shell might be the most suitable as co-firing fuel among four biomass since when 10% of walnut shell was co-fired with 90% of coal on thermal basis, flue gas production and power consumption of auxiliary systems were the smallest than those of other biomass co-firing while net plant efficiency was relatively higher than those of other biomass co-firing. However, with increasing walnut shell co-firing ratios, boiler efficiency and net plant efficiency were expected to decrease rather than coal combustion without biomass co-firing.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.674-682
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• 2017

This paper presents an optimal initial firing angle control based on the energy consumption and regenerative energy of a parallel multi-pulse thyristor dual converter for urban railway power substations. To prevent short circuiting the thyristor dual converter, a hysteresis band for maintaining a zero-current discontinuous section (ZCDS) is essential during mode changes. During conversion from the ZCDS to forward or reverse mode, the DC trolley voltage can be stabilized by selecting the optimal initial firing angle without an overshoot and slow response. However, the optimal initial firing angle is different depending on the line impedance of each converter. Therefore, the control algorithm for tracking the optimal initial firing angle is proposed to eliminate the overshoot and slow response of DC trolley voltage. Simulations and experiments show that the proposed algorithm yields the fastest DC voltage control performance in the transient state by tracking the optimal firing angle.

• 대한기계학회논문집A
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• 제31권7호
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• pp.764-776
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• 2007

On the human-rifle system, the human body is affected by the firing impact. The firing impact will reduce the firing accuracy and change the initial shooting posture. Therefore the study of biomechanical characteristics using human-rifle modeling and numerical investigation is needed. The musculoskeletal model is developed by finite element method using beam and spar elements. In this study structural analysis has been performed in order to investigate the human body impact by firing of 5.56mm small caliber machine gun. The firing experiments with the standing shooting postures were performed to verify analytical results. The result if this study shows analytical displacements of the human-rifle system and experimental displacements of the real firing. As the results, the analytical displacement and stress of human body are presented.

• 정보과학회지
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• 제5권1호
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• pp.62-78
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• 1987

인체의 신경조직에서 정보를 전달하기 위해서 발생하는 Signal인 spontaneous firing의 origin을 조사하기 위해서 Hodgkin-Huxley의 수학적 모델을 기초로 하여 Simulation을 하였다. 그 모델의 Parameter인 Stimulus current를 zero로 함으로써 생리학적으로는 stimulus없이 어떤 특정한 근육근 등에서 발생되는 spontaneous firing의 경우가 되었고 또한 physical meaning들을 포함하고 있는 parameter들의 상호 독립적 상태를 초래하여 그 firing의 origin을 연구할수 있게 되었다. 이 simulation을 통하여 얻어진 수확들은 origin에 대한 조사 연구뿐만 아니라 많은 새로운 사실의 발견에도 존재한다. 그 예로서는 이 simulation이 stimulus 없이 spontaneous firing을 얻은 최초가 되며 이 분야에 명성있는 학자들이 simulation을 통해서는 매우 제한된 수의 firing만을 얻을수 있다고 단언했으나 그 반증이 여기에서 입증되었고 leakage conductance의 중요성을 예측하게 한다. 특히 leakage potential이 firing의 수를 조정할수 있다는 것은 특이한 발견이다.

• 대한산업공학회지
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• 제42권2호
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• pp.122-128
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• 2016

The purpose of this study is to improve the firing elevation driving method for towed howitzer to prevent the musculoskeletal disorders. To adjust the firing elevation, it is required to rotate the hand wheel and this work has been done manually in the firing test range as the same method as field artillery troops. In the firing test range, the motor-driven firing elevation adjustment device was developed to improve the working efficiency and safety. These were compared by using posture classification scheme of RULA and REBA. It was measured elapsed time to investigate the improved operational efficiency. The optimal posture of upper body to operate the hand wheel for field artillery troops was proposed.

• 보존과학연구
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• 통권27호
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• pp.145-163
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• 2006

This study is to be investigated through firing experiment in studio in order to reveal a physical properties of celadon according to change firing temperature. The results can be briefly summarized as below; Firstly, in measurement of color chromaticity, samples of first firing in body were effective in differentiating of changed color in samples from each other but there of second firing were not. The color of the glaze was more effective change than that of the body. Secondly, bulk density of body was increased with temperature and it was attained highest point in $1200^{\circ}C$ Additionally, water absorption ratio was most rapidly changed between $1000^{\circ}C$ and $1200^{\circ}C$Thirdly, in the microstructural analysis, body of samples in first firing have not specific characteristics in the changed patterns of microstructure. body and glaze of samples in second firing have many that. Consequently, we knew that this experiment can be provided researcher with physical properties and firing mechanisms of celadon.

• 한국연소학회지
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• 제22권1호
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• pp.14-22
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• 2017

Co-firing of renewable fuel in coal fired boilers is an attractive option to mitigate $CO_2$ emissions, since it is a relatively low cost option for efficiently converting renewable fuel to electricity by adding biomass as partial substitute of coal. However, it would cause reducing plant efficiency and operational flexibility, and increasing operation and capital cost associated with handling and firing equipment of renewable fuels. The aim of this study is to investigate the effects of biomass co-firing on $CO_2$ emission and capital/operating cost. Wood pellet, PKS (palm kernel shell), EFB (empty fruit bunch) and sludge are considered as renewable fuels for co-firing with coal. Several approaches by the co-firing ratio are chosen from previous plant demonstrations and commercial co-firing operation, and they are evaluated and discussed for $CO_2$ reduction and cost estimation.