• 한국대기환경학회지
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• 제28권5호
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• pp.527-537
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• 2012

The increasing consumption of pseudo-petroleum products (PPP) has been disturbing the national petroleum market. The use of PPP lead to tax evasion, disturbance of sound trading principles, component corrosion of cars, and explosion accident. Also, PPP have emitted hazardous air pollutants (HAP) including the carcinogenic aromatic hydrocarbons, PAHs and aldehydes more than regular-petroleum products. It thus has potentials to cause many environmental and health care problems. In this study, benzene, toluene and xylene emissions from road transport vehicles due to the use of pseudo-gasoline are estimated for the year 2008. The results of our study provide emission estimates of benzene, toluene and xylene for the year as 405, 1,711, 717 tonne/yr, respectively for regular-gasoline. BTX emissions are calculated as 452~515, 1,882~2,264 and 732~752 tonne/yr when the amount of pseudo-gasoline is estimated to account for 6~13% for regular-gasoline consumption. BTX emissions increased as much as 12~27, 10~32, 2~5% by using pseudo-gasoline. It is found that the pseudo-gasoline should be the key component to produce HAP in urban area.

• Journal of Advanced Marine Engineering and Technology
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• 제30권1호
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• pp.22-29
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• 2006

Gas turbine engine among Principal internal combustion engines has been mainly applied as an aero and industrial Power plant. In order to increase its thermal efficiency. it has been raised their pressure ratio of compressor and the turbine inlet temperature. To operate above the limit temperature of turbine material, turbine nozzle vanes should be cooled. For this the cooling air is bled from the compressor section of 9as turbine. Meanwhile, to keep high thermal efficiency of 9as turbine, turbine vanes are to be cooled by using small cooling air Therefore, the complex cooling passages are requested to be designed and evaluated the effectiveness of vane cooling by measuring turbine vane temperature. But it is very difficult or impossible for us to measure local turbine temperatures at actual temperature When local heat transfer coefficients are known these can be calculated, therefore this study has been investigated on obtaining these coefficients of turbine vane at room temperature using TLC.

• 설비공학논문집
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• 제2권3호
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• pp.243-255
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• 1990

The objective of this study is to present an efficient measurement method of the effective thermal diffusivity for the fibrous insulation material. The non-linear parameter estimation (NPE) method is adapted for this analysis because of its accuracy and its results are compared with those by other direct methods such as CTP, CHP and STD method. A experimental system is constructed with bell-jar vaccum chamber, diffusion pump, tube type furnace, control unit and data acquisition system included with A/D converter and IBM XT/AT personal computer. The typical results obtained from this study are as follows; 1) NPE method can be recommended as an useful and accurate method to measure the effective thermal diffusivity of insuation material because it is shown that the measurement error compared with those by other direct methods is reduced for standard material, NBS-1450b. 2) NPE method can minimize the effects of ill-measured temperature due to external disturbance, because the final value is found by point to point estimating. 3) NPE method dose not depend on the kinds of heat flux, since the surfac temperature are used to estimate the thermal diffusivity. 4) With NPE method, compared with the steady state method, a measuring time and a sample size could be reduced.

• Nuclear Engineering and Technology
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• 제24권3호
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• pp.311-318
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• 1992

원자력 발전소에서 Mid-loop 운전시 배관내에서 발생하는 자유수면 와동으로 인해 잔열 제거계통 배관내 공기가 흡입될 가능성이 있으며 이로 인한 계통상실 방지를 위하여 수위와 흡입유량과의 관계를 실험을 통해서 H/d, 프라우드수, 레이놀즈 수 등과 같은 무차원 수로 구하였다. 실험결과 레이놀즈수는 크게 영향을 미치지 않았으며 주로 프라우드수가 자유수면 와동을 지배하는 것으로 판명되었다. 한편 운전시 펌프나 밸브의 개폐로 인한 수면의 섭동이 와동에 많은 영향을 미치는 것이 밝혀졌다. 원자력 발전소의 안전과 관련하여 배관내에서 와동으로 인한 공기흡입 방지책으로 Reducer형의 흡입구 개선방안을 제시하였다.

• 한국자동차공학회논문집
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• 제23권1호
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• pp.56-64
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• 2015

This study presents a model-based gain scheduling strategy for PI-based EGR controllers. The air-to-fuel ratio is used as an indirect measurement of the EGR rate. In order to cope with the nonlinearity and parameter varying characteristics of the EGR system, we proposed a static gain model of the EGR system using a new scheduling parameter. With the 810 steady-state measurements, the static gain model achieved 0.94 of R-squared value. Based on the static gain of the EGR system, the PI gains were robustly designed using quantitative feedback theory. Consequently, the gains of the PI controller are scheduled according to the static gain parameter of the EGR path in runtime. The proposed model-based gain scheduling strategy was validated through various operating conditions of engine experiments such as setpoint step responses and disturbance rejections.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2005년도 춘계 학술발표회 논문집
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• pp.295-300
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• 2005

The freeplay, one of the concentrated structural nonlinearities, is inevitable for control surfaces of a real air vehicle due to normal wear of components and manufacturing mismatches. Also aerodynamic nonlinearities caused by a shock wave occur in transonic region. In practice, these nonlinearities induce the limit cycle oscillation (LCO) and decrease the transonic flutter speed. In this study, the fictitious mass method is used to apply a modal approach to nonlinear structural models due to freeplay. The transonic small-disturbance (TSD) equation is used to calculate unsteady aerodynamic forces in transonic region. Nonlinear aeroelastic time responses are predicted by the coupled time integration method (CTIM). This method was also applied to a 3D all-movable control wing to investigate its nonlinear aeroelastic responses. The angle of attack effect on the LCO characteristics has been found to be closely related with the initial pitching moment.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.367-371
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• 2005

Social noise survey on multiple residential noises such as nut impact, air-borne, bathroom, drainage and traffic noises was conducted to investigate major variables affecting the overall satisfaction for noise environment The effect of individual noise perception on the evaluation of the overall noise environment was investigated through a questionnaire survey on annoyance, disturbance and noise sensitivity. Auditory experiments was also undertaken to determine noise level according to the percent of satisfaction for individual noise source. As a result of survey, it was found that satisfaction for floor impact noise most greatly affects the overall satisfaction for noise environment and annoyance most greatly affects the satisfaction for individual noise sources. Result of auditory experiment showed that the noise level of floor impact noise by bang machine, airborne, drainage and traffic noise corresponding to 50% satisfaction is 44dB($L_{i,Fmax,AW}$) and 40dBA, respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 A
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• pp.235-238
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• 2003

In this study, we propose a method of digital control to drive the vibrating gyroscope using electromagnetic-force. The gyroscope requires accurate vibration control and signal processing for high performance. Conventional PLL based analog controller is not only difficult to manufacture but also weak to outer environment such as temperatures, air pressures and etc. But digital controller using DSP can consistently maintain the cylinder vibration and perform digital signal processing regardless of disturbance. DSP's PWM function was utilized to control the vibration, and rotation-detecting algorithm was developed. Finally, the controller was verified by simulation and experiment using rotation-rate table.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.683-686
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• 2005

This paper is related to investigate adding effect of fluorine-silicate hybrid type crack controlling agent(FS) on initial behavior, dynamic properties, adibatic hydration temp, and plastic crack behavior of concrete(Specification : 25-30-18). It is appeared that adding of FS contributed to strength elevation, lowering of hydration temperature as well as plastic crack reduction without disturbance of initial behaviors of concrete such as slump, air content and setting.

• Journal of Mechanical Science and Technology
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• 제20권7호
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• pp.993-1001
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• 2006

In this paper, a method of accurate position control using a pneumatic cylinder driving apparatus is presented. To overcome the effect of friction force and transmission line, low friction type cylinder applied externally pressurized air bearing structure is used and two control valves attached both side of the cylinder directly. To compensate nonlinear characteristics of control valves, linearized control input derived from the relation between control input and effective area of control valve, and dither signal are applied to the valve. The controller applied to the pneumatic cylinder driving apparatus is composed of a state feedback controller and a disturbance observer. Experimental results show that the effectiveness of the proposed method and position control error of $5{\mu}m$ accuracy could be obtained easily.