• Proceedings of the KIEE Conference
• /
• 2015.07a
• /
• pp.1535-1536
• /
• 2015

CMOS realization of VDTA (Voltage Differencing Transconductance Amplifier) - Gm and its application in the design of multifunctional filter is presented. Small signal analysis is also done to simplify and depict the realization method. Also the parameters and can be tuned by adjusting the circuit components. The performance of VDTA-Gm amplifier and the designed Band Pass filter are simulated using HSPICE with CMOS $0.18{\mu}m$ process parameters.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.14 no.5
• /
• pp.1112-1118
• /
• 1990

The end tip position control of a flexible robot arm has been presented by utilizing the feedback signal from the rate-gyro mounted at the end tip. Kalmann filter and the state feedback gains were determined by optimal sense based upon the parameter from the geometrical and electrical data of the flexible arm system. The simulation and experiment were performed and it has been proved that implementation of the rate-gyro drastically improves the performance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1999.11a
• /
• pp.155-158
• /
• 1999

Because the traditional filters have many demerits, multi-step electric oil filter have manufactured the efficiency of insulating oil to improve. Therefore, the function of oil filter to improve based on my experience and know-how about my job. Through this study have obtained many merits. The efficiency of insulating oil is improved. The waste oil reused in repair works of the damaged transformer. Multi-step filter is shortening the working time and safety. it is handy for use and movement. This study lengthen the expected life span of filter. The improvement of oil filter bring about elevation of productivity.

• Applied Chemistry for Engineering
• /
• v.30 no.6
• /
• pp.712-718
• /
• 2019

A combustible producer gas composed of H₂, CO and CH₄ could be obtained by the thermal-chemical conversion of biomass. However, a large amount of particulate matters including tar generated causes the mal-function of turbines and engines or the fouling of pipelines. In this study, a wet scrubber using the soybean oil and bag filter were installed, and the removal efficiency was investigated. Hydrate limestone and wood char base activated carbon were pre-coated on the filter medium to prevent clogging of open pores. The removal efficiencies by the bag filter were 86 and 80% for the hydrated limestone and activated carbon coating, respectively. Overall, the collection when using a series of oil scrubbers and bag filters were 88%, while 83% for the filter coating material.

• Textile Coloration and Finishing
• /
• v.35 no.4
• /
• pp.256-273
• /
• 2023

Among the dyeing industries, the tenter process is a process that improves the quality of fibers by drying and ironing (heat treatment) dyed fabrics, and drugs such as water repellents, antistatic agents, and fiber softeners are mainly used in these tenter processes. These drugs are vaporized in the process of treatment by high temperatures (180 ~ 230℃), and are observed in a complex form such as white smoke, oil mist, and fine dust, causing odor. To treat the complex exhaust gas at the rear end of the tenter facility, most companies operate by installing a wet scrubber and an adsorption tower alone or in parallel, but there are many problems. In particular, the insoluble oil mist at the rear end of the tenter has significantly low processing efficiency in the cleaning dust collection facility, and there is a problem in the facility by adsorption due to the occlusion phenomenon caused by the oil mist. In addition, the odor gas at the rear end of the tenter contains a lot of aldehydes, and in order to improve these various problems, a complex exhaust purification device using cyclone and electric support collector was developed. This study examined the applicability of economical and efficient technology by removing complex air pollution at the rear end of the tenter and applying improved technology than the existing technology.

• Korean Chemical Engineering Research
• /
• v.46 no.1
• /
• pp.194-199
• /
• 2008

In this study, the effective method to esterify the free fatty acids in jatropha oil was examined. Compared to other plant oils, the acid value of jatropha oil was remarkably high, 11.5 mgKOH/g. So direct transesterification by a base catalyst was not suitable for the oil. After the free fatty acids were esterified with methanol, jatropha oil was transesterified. The activities of four solid acid catalysts were tested and Amberlyst-15 showed the best activity for the esterification. After constructing the experiment matrix based on RSM and analyzing the statistical data, the optimal esterification conditions were determined to be 6.79% of methanol and 17.14% of Amberlyst-15. After the pretreatment, jatropha biodiesel was produced by the transesterification using KOH in a pressurized batch reactor. Jatropha biodiesel produced could meet the major specifications of Korean biodiesel standards; 97.35% of FAME, 8.17 h of oxidation stability, 0.125% of total glycerol and $0^{\circ}C$ of CFPP.

• Economic and Environmental Geology
• /
• v.46 no.1
• /
• pp.51-61
• /
• 2013

Researches on the oil recovery enhancement using the nanotechnology has recently been studied in the United States. The previous researches has focused mainly on the flow characteristics of nanoparticles in porous media, and the stability of the nano-emulsion itself. However, the analysis did not deal with the size effects between a nano-emulsion and the pore size which has an important role when nano-emulsion flows in the porous media. In this research, nano-based emulsion was fabricated which is able to be applied for the enhanced oil recovery techniques and its characteristics was analyzed. In addition, in order to identify the characteristics of nano-emulsions flowing through the porous media, the size effect was analysed by filtering test. According to the results, when the emulsion was fabricated, SCA(Silane Coupling Agent) or PVA(Poly Vinyl Alcohol) are added to improve the stability of emulsion. As the ratio of the decane to water increased, the viscosity of emulsion and the droplet size also increased. For the filtering test at the atmospheric conditions, the droplet did not go through the filter; only the separated water from the emulsion was able to be filtered. This phenomenon occurred because the droplet was not able to overcome the capillary pressure. At the filtering test by suction pressure, most of the emulsion was filtered over the filter size of $60{\mu}m$. However, the ratio of filtration was rapidly degraded at less than $45{\mu}m$ filters. This is caused due to deformation and destruction of the droplet by strong shear stress when passing through the pore. The results from the study on the basic characteristic of nano-emulsion and filtering test will be expected to play as the important role for the fabrication of the stable nano-emulsion or the research on the recovery of residual oil in porous media.

• Tribology and Lubricants
• /
• v.25 no.5
• /
• pp.318-323
• /
• 2009

The oil characteristics and wear particles of Diesel engines with a DPF have been investigated as a function of a driving distance. The engine oil of SAE 5W30 with ACEA C3 is used for an oil film lubrication of the engine, which is equipped with Diesel particulate filter. Depending on the oil test results, the kinematic viscosity of used engine oils at 40 is degraded up to 5.1% compared with that of unused engine oils, SAE 5W30. And the kinematic viscosity of used engine oils at 100 is more degraded up to 8.1% compared with that of unused engine oils. The oil characteristic as a function of a mileage is not changed depending on the driving distance because of high quality of engine oils. But the aluminum and copper compounds, which are used as base materials of the engine bearing and a pin bush, are much worn and contaminated for the increased mileage of the car. The oil properties of used engine oils are relatively good except phosphorus and calcium additives, which are heavily engaged in the performance of the oils.

• Applied Chemistry for Engineering
• /
• v.20 no.2
• /
• pp.208-212
• /
• 2009

Biodiesel come from animal fat and vegetable oil by methanolysis was known for eco-friendly fuel for the alternative petrodiesel. But, various kinds of biodiesel need to analyze the cold characteristic due to poor fuel properties than petrodiesel in a cold condition. In this paper, 12 types of biodiesel were synthesized in 86~96% yields from 12 kinds of vegetable oil by transesterification. These synthesized biodiesels were analyzed in terms of the cold characteristics like cloud point, pour point, and cold filter plugging point (CFPP). The biodiesel comes from perilla oil which has rich olefin showed the excellent fuel characteristics in a low temperature.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2022.11a
• /
• pp.767-769
• /
• 2022

본 논문에서는 현대인들의 일상생활 속 누적된 스트레스를 완화하고 사용자의 편의를 고려한 "아로마테라피를 지원하는 지능형 샤워부스" 시스템을 제안한다. 제안하는 시스템의 주요 기능은 다음과 같다. 첫째, 적외선 온도 센서와 초음파 센서, 카메라를 통해 사용자의 신체 정보와 기분을 측정한다. 둘째, 측정된 사용자의 신체 정보를 반영하여 Linear actuator를 이용해 샤워기의 높낮이 및 수온을 자동으로 조절한다. 셋째, OpenCV와 앱 내에 만족도 평가를 통해 사용자의 기분에 따라 알맞은 아로마오일을 추천하고 이를 샤워기 필터에 주입한다. IoT기술과 연동된 샤워부스 시스템을 통해 사용자 컨디션에 맞춘 아로마테라피를 지원하여 현대인의 지친 심신 회복과 사용자 편의성이 증대될 것으로 기대된다.