• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.110.1-110.1
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• 2010

A bench scale slurry bubble column reactor (SBCR) with active-Fe based catalyst was developed for the Fischer-Tropsch synthesis (FTS) reaction. Considering the highly exothermic reaction heat generated in the bench scale SBCR, an effective cooling system was devised consisting of a U-type dip tube submerged in the reactor. Also, the physical and chemical properties of the catalyst were controlled so as to achieve high activity for the CO conversion and liquid oil ($C_{5+}$) production. Firstly, the FTS performance of the FeCuK/$SiO_2$ catalyst in the SBCR under reaction conditions of $265^{\circ}C$, 2.5 MPa, and $H_2/CO=1$ was investigated. The CO conversion and liquid oil ($C_{5+}$) productivity in the reaction were 88.6% and 0.226 $g/g_{cat}-h$, respectively, corresponding to a liquid oil ($C_{5+}$) production rate of 0.03 bbl/day. To investigate the FTS reaction behavior in the bench scale SBCR, the effects of the space velocity and superficial velocity of the synthesis gas and reaction temperature were also studied. The liquid oil production rate increased upto 0.057 bbl/day with increasing space velocity from 2.61 to 3.92 $SL/h-g_{Fe}$ and it was confirmed that the SBCR bench system developed in this research precisely simulated the FTS reaction behavior reported in the small scale slurry reactor.

• 터널과지하공간
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• 제18권6호
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• pp.427-435
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• 2008

본 연구에서는 지반등급 V중에서 막장자립이 곤란한 지반에 대해 지반고유의 지지력을 최대한 이용하기 위한 굴착공법 및 적정벤치길이에 대해 검토하고, 보조공법으로 막장볼트를 적용할 경우 타설 패턴, 타설 개수에 따라 막장 및 막장주변지반에 어떠한 영향이 발생되는지에 대해 3차원 FEM해석을 수행하였다. 보조벤치 병용전단면공법이 조기 단면폐합으로 변위를 크게 줄일 수 있음을 알 수 있었으며, 타설 패턴으로는 격자상, 교호배치형(지그재그형), 원주상순으로 변위억제효과가 있는 것으로 나타났다. 또한 타설 개수 증가에 따라 막장축방향 수평변위에 대해 억제효과가 있는 것으로 분석되었으며 보조벤치 병용 전단면공법굴착시공의 경우 막장부 $1.5m^2$에 1개의 막장볼트(격자상) 타설로 막장면 안정성을 확보할 수 있을 것으로 판단되었다.

• 한국항행학회논문지
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• 제19권6호
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• pp.473-483
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• 2015

본 논문에서는 1축 자세제어실험 장비를 제작하여 쿼드로터 형 무인항공기에 적용할 단일입력-단일출력 Cascade 제어기 실험을 수행하였다. 해당 장비는 두 개의 모터와 프로펠러에 의해 자세변화가 가능한 시소 형태로 구현하였고, 무게 추를 변경하여 회전축을 중심으로 상하 무게중심 이동이 가능하도록 제작하였다. 개발한 장비를 통해 Cascade 구조를 가지는 PID(각도)-PID(각속도) 제어기를 구성하여 실험을 수행하였으며, PID 이득의 조정을 용이하게 하는 SIMC 제어기 이득 조정 기법을 Cascade 제어에 접목하였다. 이를 위해 Matlab-Simulink 환경 하에 2차 시간 지연 모델을 구축하여 시스템 변수 추정을 수행하였다. 기존의 SIMC 조정 기법 적용 과정을 수행하여 그 특성을 파악하고, 적용 과정의 안정성 문제를 고려하여 수정된 방안을 제시하였으며, 이를 1축 자세제어실험 장비에 적용하여 기존의 과정과 수정된 과정을 비교 실험하였다.

• 분석과학
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• 제23권1호
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• pp.74-82
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• 2010

휴대형 형광 분석기의 개발을 위한 사전 기초연구로서 탁상형 및 휴대형 X-선 형광분석기를 이용하여 플라스틱 중의 Cd, Pb, Hg, Cr (IV), polybrominated biphenyls (PBB) 및 polybrominated diphenyl ethers (PBDE)의 RoHS 규제 물질에 대하여 비교 분석하였다. 규제 물질이 0~1,200 mg/kg의 농도로 함유된 폴리에틸렌 및 폴리프로필렌 인증표준물질을 사용하여 측정시간에 따른 최적의 분석 조건을 확립하고, 각 규제 물질의 검량곡선을 작성하였다. 플라스틱 인증표준물질과 시료 중의 Pb, Hg, Cd, 총 Cr 및 총 Br 함량을 탁상형 X-선 형광분석기의 empirical (EM) 법 및 fundamental parameter (FP) 법으로 정량분석하고 그 결과를 휴대형 X-선 형광분석기와 비교 하였다.

• 대한기계학회논문집 C: 기술과 교육
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• 제2권1호
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• pp.1-8
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• 2014

최근 차량이 기계장치 중심에서 전기전자 장치 중심으로 발전하고 있으며, 상용차량 역시 전기전자 장치가 증대되고 있다. 정전용량 방식의 연료 센서는 연료의 레벨을 정전용량 값으로 측정하여 센서 내 MCU 를 통해 연산과정을 거쳐 최종 전압값의 신호로 출력해 주는 센서이다. 기존의 세라믹 저항을 이용한 센서보다 내구성이나 연료 측정 정확성이 향산된 진보된 센서로 센서에 대한 소프트웨어 검증을 위하여 가변 커패시터 보드를 제작하여 R-BENCH TOOL 을 통해 test case 를 자동으로 생성시킨 후 연료 센서의 소프트웨어 검증을 시도하였다. 또한 결론으로 98% 이상의 높은 소프트웨어의 신뢰도가 있음을 확인하였다.

• Tribology and Lubricants
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• 제30권5호
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• pp.271-277
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• 2014

Hydraulic reciprocating seals have been widely used to prevent fluid leakage and to provide lubricant film on counter surface in various hydraulic system. The degradation of the seal may cause the catastrophic failure of the hydraulic system. To assess the durability of the seals and the compatibility with counter surface, accelerated life testing (ALT) has been typically employed from industry. However, ALT often takes up to a few months to cause a failure of the seals, and therefore, there is a need to develop more efficient ALT methods. In this work, the degradation characteristics of polyurethane (PU) seals from field test are investigated and they are compared to those from the component and bench tests, with an aim to contribute to the development of ALT method. From the comparison of the cross-sectional profiles of the sealing surface of the PU specimens before and after the tests, both wear and compression set are found to be responsible for degradation of the PU seals. It is also shown that the major wear mechanisms of the PU seals from the field is abrasive wear and formation of pits. The component and bench tests performed in this work are shown to reproduce such wear mechanisms, and therefore, those test methods can be used as an ALT method for PU seals. In particular, the bench test proposed in this work may be effectively utilized to assess the durability and the compatibility of the seals with the counter surface. The results of this work are expected to aid in the design of ALT for PU seal.

• 한국자동차공학회논문집
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• 제17권1호
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• pp.114-119
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• 2009

The authors have investigated the NVH problems of drive system in full vehicle test. However it is difficult to define the NVH problems of driveline system. Since it is hard to measure the rotating part and it is vague that only the drive system induces the NVH problem. Vibration in a driveline is presented in this paper. In the experiment, the rear sub-frame and propeller shafts and axle were composed and mounted with rubber each other. For applying the vibration input instead of the torsional vibration effect of an engine, the shaker was taken. In particular, torsional vibration due to fluctuating forced vibration excitation across the joint between driveline and rear sub-frame was carefully examined. Accordingly, the joint response was checked from experiments and the FE-simulation using FRF (frequency response function) analysis was performed. All test results were signal processed and validated against numerical simulations. In present study, the new test bench for measuring the vibration signal and simulating the vehicle chassis system was proposed. The modal value and the mode shape of components were analyzed using the CAE model to identify the important components affecting driveline noise and vibration. It could be reached that the simplified test bench could be well established and be used for design guide and development of the vehicle chassis components.

• 한국수처리학회지
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• 제26권6호
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• pp.53-59
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• 2018

Water pollution is drastically increasing day by day, because of the enhancement in use of livestock, urban sewage detergents and fertilizers. Moreover increase in concentration of phosphorous and nitrogen contained in sewage, leads to green tide problem in the rivers and causes marine pollution. For this problem to solve, several technologies are being researched and developed. Among them, this experiment is a study on Bench-scale STP based on internationally certified sewage treatment equipment by MEPC. 227(64) of IMO. The purpose of this study is to compare the biological treatment efficiency of phosphorus of Bench-scale STP. The ratio of C : N : P was set to 10 : 5 : 3 and 10 : 3 : 1 as the operating conditions. And the operation cycle was set to anoxic(mixed) 70 min - aeration 50 min (70-50), anoxic(mixed) 90 min - aeration 60 min (90-60). As a result, the phosphorous treatment efficiency was 88% at average, and the treatment efficiency was steady at 90-60 better than 70-50. The efficiency of the bench-scale STP has been verified through this experiment and additional experiments are required to derive the optimal operating conditions.

• Medical Lasers
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• 제10권4호
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• pp.220-228
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• 2021

Background and Objectives In designing a resistance exercise program, intensity, rest, and exercise volume are important. Many studies have been conducted to find the most suitable resistance exercise program incorporating the above, and in particular, many prior studies have been conducted on intensity. This study attempted to determine the effective volume of exercise by analyzing the number of repetitions performed at intensities of 65% one-repetition maximum (1RM) and 75% 1RM during the bench press exercise, and the electromyography (EMG) response of the agonist muscle. Materials and Methods Eight males in their 20s were selected as study subjects and they performed five sets of bench presses at two levels of intensity (65% 1RM, 75% 1RM). The following results were obtained by measuring the number of repetitions and the EMG response according to the exercise intensity and sets during the workout. Results First, the number of repetitions showed a sharp drop from the first set to the third set at 65% 1RM intensity and showed no change in the fourth and fifth sets. At 75% 1RM intensity, the intensity of hypertrophy showed a gradual decrease from the first set to the fifth set. Second, at 75% 1RM exercise intensity, the pectoralis major, anterior deltoid and triceps brachii showed high muscle activity, and the activity of the anterior deltoid continued to increase from the first set to the fourth set at 65% 1RM intensity, and from the first set to the fifth set at 75% 1RM. Conclusion It was found that during the bench press exercise, three minutes of rest at 75% 1RM intensity, five sets of five sets, one minute rest at 65% 1RM intensity, and three sets of the exercise were effective.

• 지질공학
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• 제32권4호
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• pp.725-733
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• 2022

본 연구에서는 기존 패커를 개량한 하이브리드패커를 장착한 수압암반절개시스템을 벤치컷 공법에 적용하였다. 하이브리드패커는 주입압을 이용하여 수압파쇄균열을 생성시키고 고무패커를 팽창시켜 수압파쇄균열을 확장하고 연장시키는 두 가지 기능을 하나의 패커에 접목시킨 패커시스템으로, 무소음·무진동 수압암반절개에 효율적으로 적용할 수 있도록 설계되었다. 본 연구에서는 벤치컷 굴착을 위해 사면 최상단에 설치된 실험공과 자유면으로부터의 이격거리와 주입설정 등 실험조건을 조정하면서 현장실험을 수행하여 주입 조건에 따른 암반 굴착 효율성을 비교하였다. 5 m의 이격거리를 지닌 조건에서는 굴착이 이루어지지 않은 부분이 발생하였으나 1 m의 이격거리에서는 굴착되지 않은 부분이 발생하지 않았다. 주입압에 의해 생성된 수압파쇄균열은 대체적으로 자유면과 평행하게 발달하여 고무팽창에 의해 확장 및 연장되어 벤치컷 굴착이 용이하게 이루어졌다. 벤치컷 암반 굴착에 수압암반절개공법을 체계적으로 적용하기 위해서는 다양한 암반 상태에 대하여 실험조건을 변화하면서 현장실험 결과를 축적하여야 할 것으로 판단된다.