• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.1052-1055
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• 2004

This paper introduces an experimental study on the grazing incidence sound absorptions for duct silencers filed with a glass wool and consisted of a perforated panel. The experimental results are discussed in comparison with the normal incidence sound absorption. And also the transmission loss for duct silencers are measured and compared with the sound absorption performances. From the experimental results, it is shown that the resonance frequency bandwidth on the transmission loss and sound absorption coefficient for duct silencers has a good agreement.

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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• 제6권1호
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• pp.30-37
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• 2003

This paper describes vibration control of a suspended system using wave absorption method. A moving multiple-pendulum system and a moving wire-and-load system are treated. The wire-and-load system is extended to a model crane system that has a motor system to roll up and down the suspended mass like a real crane. The same program with different parameter values controls these three systems. Both numerical simulation and experiment have been conducted, and the present control method has shown to be quite effective.

• 대한환경공학회지
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• 제35권4호
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• pp.233-239
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• 2013

본 연구에서는 실험실 규모의 스크러버 전단과 후단에 설치된 가스센서의 출력값으로부터 흡수제의 실시간 흡수효율을 평가하기 위한 연구를 진행하였다. 스크러버 전단과 후단에 설치된 가스센서는 센서표면에서의 가스 흡 탈착반응으로 발생되는 전기적인 변화를 출력신호로 나타내는 측정장치이며, 스크러버의 흡수제와 암모니아 가스와의 반응시간(3시간, 6시간 및 12시간)에 따른 암모니아 가스의 흡수량을 산출하였다. 또한 가스센서의 출력값으로부터 산출된 암모니아 흡수량을 기존의 암모니아 분석방법인 인도페놀법에 의한 흡수량 산정방법과 비교해 보았으며, 약 20%의 차이를 보이긴 하나 0.99 이상의 높은 상관성을 보이고 있음을 확인하였다. 또한, 반응시간에 따른 pH와 흡수량과의 높은 상관성을 확인할 수 있었으며, 흡수제에 대한 암모니아 흡수량을 실시간으로 파악함으로써 흡수제의 파과시간을 예측할 수 있었다. 향후 다양한 연구를 통하여 악취배출시설의 스크러버에 이와 같은 가스센서를 적용하여 흡수제의 흡수 효율을 실시간으로 평가하여 교체주기 및 효율 등을 실시간으로 평가할 수 있는 시스템으로 발전이 가능함을 확인하였다.

• 설비공학논문집
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• 제17권4호
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• pp.312-317
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• 2005

The objectives of this paper are to study the absorption characteristics of $NH_3$ bubbles in the binary nanofluids and to quantify the effects of surfactants and nano-particles on the bubble absorption performance. 2-Ethyl-1-Hexanol, n-Octanol, and 2-Octanol are used as the surfactants and nano-sized $Al_{2}O_3$ and Cu particles are added to make the binary nanofluids into $NH_3/H_{2}O$ solution. The concentration of $NH_3$ solution ($x_s$), the concentration of surfactants ($x_{SA}$), and the mass fraction of nano-particles ($w_{np}$) are considered as key parameters. The experimented ranges of $x_s,\;x_{SA},\;and\;w_{np}$ are $0{\sim}17.92\%,\;0{\sim}1,500\;ppm\;and\;0{\sim}0.2\%$, respectively. The absorption rates are calculated by measuring initial and final weights of test section and exposed time. In addition, the bubble absorption processes are visualized using the shadow graphic method. The results show that the absorption performance is significantly enhanced up to 4 times by adding the surfactants and up to 3 times in the binary nanofluids.

• 한국환경농학회:학술대회논문집
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• 한국환경농학회 2011년도 30주년 정기총회 및 국제심포지엄
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• pp.237-238
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• 2011

• 한국분무공학회지
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• 제9권4호
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• pp.67-76
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• 2004

Diode laser absorption sensors are advantageous because they may provide fast, sensitive, absolute, and selective measurements of species concentration. These systems are very attractive for practical applications owing to its compactness, reasonable cost, robustness, and ease of use. In addition, diode lasers we fiber-optic compatible and thus enable simultaneous measurements of multiple species along a line-of-sight. Recent advances of room-temperature, near-IR and visible diode laser sources for telecommunication, optical data storage applications make it possible to be applied for combustion diagnostics based on diode laser absorption spectroscopy. Therefore, combined with fiber-optics and high sensitive detection strategies, compact and portable sensor systems are now appearing for variety of applications. The objectives of this research are to develop new gas sensing system and to verify feasibility of this system. Wavelength modulation spectroscopy has been demonstrated in these experiments and has a bright prospect to this diode laser system.

• Steel and Composite Structures
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• 제36권2호
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• pp.197-211
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• 2020

Application of the steel ring as a type of seismic fuse has been one of the efforts made by researchers in recent years aiming to enhance the ductility of the bracing systems which in turn, possesses various advantages and disadvantages. Accordingly, to alleviate these disadvantages, an innovative bracing system with a diamond scheme equipped with a steel ring is introduced in this paper. In this system, the braces and yielding circular damper act in parallel whose main functionality is to increase ductility, energy absorption and mitigate drawbacks of the existing bracing systems, in which the braces and yielding circular damper act in parallel. To conduct the experimental tests, specimens with three types of rigid, semi-rigid and pinned connections were built and subjected to cyclic loading so that their performance could be analyzed. Promisingly, the results indicate both great applicability and efficiency of the proposed system in energy absorption and ductility. Moreover, it was concluded that as the braces and damper are in parallel, the use of a steel ring with smaller size and thickness would result in higher energy absorption and load-resisting capacity when compared to the other existing systems. Finally, to assess the potential of numerically modeling the proposed system, its finite element model was simulated by ABAQUS software and observed that there is a great agreement between the numerical and experimental results.

• 한국소음진동공학회논문집
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• 제16권9호
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• pp.964-970
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• 2006

Micro gas turbine(MGT) has received attention recently as small-scale distributed power sources. With characteristics such as their small size, lightweight, low maintenance cost and minimal vibrations during operation, they are expected to become widespread in a wide range of ' applications, including residential and small-scale industrial use. It is very easier to start-up and stop the MGT system which is the friendly environmental power system has just below the 9ppm NOx emmission and good quality of noise level. The exhaust heat emitted by the MGT is in the form of about $300^{\circ}C$ clean exhaust gas. The exhaust gas is suitable for absorption chiller/heater system. 1 has researched performance characteristics of the 60 kW class MGT-absorption chiller-heater system in the local condition. Variations of heat recovery from exhaust gas has measured according to micro gas turbine output of 15, 30, 45, 60kW. From those results, the performance of the MGT-absorption chiller/heater system has been evaluated.

• 태양에너지
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• 제9권3호
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• pp.73-80
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• 1989

This paper presents as assessment based on steady-state thermodynamic analysis and computer modeling of a double effect generation absorption heating cycle for solar air-conditioning to find operating temperature ranges. The influences of component temperatures on the heating coefficients of performance and mass flow ratio have been investigated to obtain optimum operating conditions for the proposed air conditioning system. And the single and double effect absorption cycles are compared with each other over the same range of temperatures.

• 대한수학회지
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• 제44권4호
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• pp.779-786
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• 2007

In this note, we consider a system of two reaction-diffusion equations with absorption, under homogeneous Dirichlet boundary. Using scaling methods, we establish the blow-up rate estimates.