• KSBB Journal
• /
• v.24 no.4
• /
• pp.367-376
• /
• 2009

In this study, two supercritical extraction systems of different scale, analytical-scale and lab-scale, were employed to investigate the extraction efficiency of canola oil from canola seeds using supercritical carbon dioxide ($SCCO_2$) as an extraction solvent. The effects of various parameters such as extraction temperature ($40{\sim}80^{\circ}C$), pressure (200~500 bar), particle size, and $SCCO_2$ flow direction on the extraction rate and yield were examined in detail. Triglycerides and fatty acids in the extracted canola oil were analyzed quantitatively by high-performance liquid chromatography and gas chromatography. The solubility values of canola oil in $SCCO_2$ could be calculated from the experimental results. Similar extraction yields were obtained from both analytical-scale and lab-scale extraction systems. The extraction rates obtained under solvent ($SCCO_2$ ) upflow conditions were found to be higher than those of solvent downflow extraction. However, the effect of $SCCO_2$ flow direction on the extraction yield was observed to be relatively insignificant.

• Korean Journal of Poultry Science
• /
• v.41 no.2
• /
• pp.99-104
• /
• 2014

The objective of this study is to analyze the production of extra-large egg and assess the impacts of exogenous factors in feeding the layer chicken. The main results of this study are as follows; First, feeding rations on the basics of statistics, internal maximum and minimum temperature and, the age at first egg affect the production of extra-large egg. Second, implicating the standardized coefficients from the conclusion of regression model estimating suggest that the amount of feed has the greatest impact on production followed by the age at first egg. Third, by using the elasticity of output and the volatility in the production, the result suggest that among the independent variable factors in the external volatility, the biggest one goes to feed ration, and the age at first egg follows. In order to control the production volatility in the extra-large egg production of the farms, it is necessary to manage an efficient feeding based on feed ration, age at first egg and, the maximum and minimum temperature inside the farm. Taken together, the results demonstrates that it should be concentrated by controlling the exogenous factors affecting extra large egg production and the management system construct, to increase extra-large egg production and the income of farmers at the same time.

• Journal of Korean Society of Environmental Engineers
• /
• v.29 no.5
• /
• pp.577-583
• /
• 2007

To overcome certain disadvantages of past typical control techniques for toxic contaminants emitted from various industrial processes, the current study was conducted to establish a thermal catalytic system using mesh-type transition-metal platinum(Pt)/stainless steel(SS) catalyst and to evaluate catalytic thermal destruction of five chlorinated hydrocarbons[chlorobenzene(CHB), chloroform(CHF), perchloroethylene (PCE), 1,1,1-trichloroethane(TCEthane), trichloroethylene(TCE)]. In addition, this study evaluated the catalyst poison effect on the catalytic thermal destruction. Three operating parameters tested for the thermal catalyst system included the inlet concentrations, the incineration temperature, and the residence time in the catalyst system. The thermal decomposition efficiency decreased from the highest value of 100% to the lowest value of almost 0%(CHB) as the input concentration increased, depending upon the type of chlorinated compounds. The destruction efficiencies of the four target compounds, except for TCEthane, increased upto almost 100% as the reaction temperature increased, whereas the destruction efficiency for TCEthane did not significantly vary. For the target compounds except for TCEthane, the catalytic destruction efficiencies increased up to 30% to 97% as the residence time increased from 10 sec to 60 sec, but the increase of destruction efficiency for TCEthane stopped at the residence time of 30 sec, suggesting that long residence times are not always proper for thermal destruction of VOCs, when considering the destruction efficiency and operation costs of thermal catalytic system together. Conclusively, the current findings suggest that when applying the transition-metal catalyst for the better destruction of chlorinated hydrocarbons, VOC type should be considered, along with their inlet concentrations, and reaction temperature and residence time in catalytic system. Meanwhile, the addition of high methyl sulfide(1.8 ppm) caused a drop of 0 to 50% in the removal efficiencies of the target compounds, whereas the addition of low methyl sulfide (0.1 ppm), which is lower than the concentrations of sulfur compounds measured in typical industrial emissions, did not cause.

• Korean Chemical Engineering Research
• /
• v.53 no.4
• /
• pp.445-449
• /
• 2015

This study was directed to finding an optimum extraction condition of genistein from the S. flavescens with supercritical carbon dioxide as a solvent. In this effort, effects of the extraction conditions including pressure, temperature and a co-solvent on the extraction efficiency were investigated. The aqueous ethanol and methanol solutions were used as co-solvents while the tested operating pressure and temperature ranges were from 200 bar to 300 bar and from 308.15 K to 323.15 K, respectively. The concentration of genistein was determined by means of HPLC equipped with a UV detector. From the results, it was observed that an increase in pressure led to the higher extraction efficiency. Further, methanol showed better performance as a co-slovent than ethanol. The DPPH radical scavenging activities were measured to compare antioxidant activities of S. flavescens extracts.

• Applied Biological Chemistry
• /
• v.39 no.4
• /
• pp.327-331
• /
• 1996

This experiment was conducted to establish the efficient extraction condition for anthocyanin and tannin pigments contained in rice bran of colored rices. Efficiency of the pigment extraction was maximum when the concentration of mired solvent of methanol(3) : ethanol(7) was 70%. In purple rite(anthocyanin pigment), ‘Kilimheugmi’, 80% ethanol containing 0.5% malic acid showed the highest extraction efficiency and stability with a maximum absorbance wavelength$(\lambda_{max})$ at 538 nm. In red rice(tannin pigment), ‘Jagwangdo’, 80% ethanol containing 0.01% citric acid showed the highest extraction efficiency and stability with a maximum absorbance wavelength$(\lambda_{max})$ at 456 nm. The relative optical density of the pigments increased until the solvent temperature was reached at $70^{\circ}C$, but drastically decreased over at $90^{\circ}C$ due to color change. The higher amount of the pigment was ertracted from the longer shaking time of the solvent. Ten minutes was enough for the grinding time of rite bran in solvent. Supernatant of the pigment extractives after one day storage at $4^{\circ}C$ in dark chamber revealed higher optical density than the filtration of the pigment extractives.

• Journal of Korea Society of Industrial Information Systems
• /
• v.29 no.2
• /
• pp.47-54
• /
• 2024

The global decrease in traditional energy resources has prompted increasing energy demand, necessitating efforts to replace and optimize energy sources. This study focuses on enhancing energy efficiency in manufacturing plants, known for their high energy consumption. Through simulations and analyses, the study proposes a temperature-based control system for HVAC (Heating, Ventilating, and Air Conditioning) operations, utilizing machine learning algorithms to predict and optimize factory temperatures. The results indicate that this approach, particularly the prediction-based free cooling algorithm, can achieve over 10% energy savings compared to existing systems. This paper presents that implementing an efficient HVAC control system can significantly reduce overall factory energy consumption, with plans to apply it to real factories in the future.

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.06a
• /
• pp.249.1-249.1
• /
• 2010

현재 농업부산 폐자원은 퇴비, 가축사료 등의 단순 활용이 대부분을 차지하고 있어, 열분해 가스화를 통한 고효율 에너지 이용 시스템 개발로 기존 단순 활용에 그치던 농업부산 폐자원의 고부가가치 이용이 절실히 필요한 실정이다. 본 연구에서는 초본계 농업부산물인 왕겨를 이용한 열분해 가스화 시스템에 대한 특성 파악 및 초본계 농업부산물을 이용한 에너지자원화 및 고효율 에너지 이용을 위한 방안을 모색하고자 다양한 조건에서 전산해석을 수행하였다. 공정해석에 사용된 왕겨는 수분함량 11.33%, 회분함량 10.66%, 가연분 함량, 78.01%의 조성으로, 발열량은 LHV 기준으로 3,729 kcal/kg 였다. 상용해석 프로그램을 사용하여 열분해로의 열손실, 투입되는 시료의 가스화 반응 비율 변화, 열분해 가스화 반응의 산화제로 사용되는 공기의 유량 변화에 따른 발생되는 가스의 유량, 성상, 온도 특성을 파악하였다.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.41 no.11
• /
• pp.699-707
• /
• 2017

This study presents a comparative thermodynamic analysis of subcritical and transcritical organic Rankine cycles for the recovery of low-temperature heat sources considering nine substances as the working fluids. The effects of the turbine inlet pressure, source temperature, and working fluid on system performance were all investigated with respect to metrics such as the temperature distribution of the fluids and pinch point in the heat exchanger, mass flow rate, and net power production, as well as the thermal efficiency. Results show that as the turbine inlet pressure increases from the subcritical to the supercritical range, the mismatch between hot and cold streams in the heat exchanger decreases, and the net power production and thermal efficiency increase; however, the turbine size per unit power production decreases.

• Korean Journal of Optics and Photonics
• /
• v.28 no.5
• /
• pp.241-249
• /
• 2017

This paper presents the design and evaluation of the optical system for an uncooled thermal-imaging camera. The operating wavelength range of this system is from $7.7{\mu}m$ to $12.8{\mu}m$. Through optimization, we have obtained a LWIR (Long Wave Infrared) optical system with a focal length of 5.44 mm, which consists of four aspheric surfaces and two diffractive surfaces. The f-number of the optical system is F/1.2, and its field of view is $90^{\circ}{\times}67.5^{\circ}$. The hybrid lens was used to balance the higher-order aberrations, and its diffraction properties were evaluated by scalar diffraction theory. We calculated the polychromatic integrated diffraction efficiency, and the MTF drop generated by background noise. We have evaluated the thermal compensation of a LWIR fixed optical system, which is optically passively athermalized to maintain MTF performance in the focal depth. In conclusion, these design results are useful for an uncooled thermal-imaging camera.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.256.1-256.1
• /
• 2014

21세기 정보화 시대의 도래와 함께 반도체 및 디스플레이 분야는 고부가가치산업으로 급격히 성장하였고, 현재까지도 미래의 지속적인 시장 창출을 위하여 기술개발과 투자로 초미세화, 고효율, 대면적화에 대한 원천기술 확보가 중요시되고 있다. 반도체 및 디스플레이의 대면적화가 진행됨에 따라 플라즈마 공정장비의 대면적화도 활발히 기술개발이 진행되고 있으며, 대면적화에 있어 플라즈마의 공간균일도는 생산수율 및 공정균일화를 위해 기본적으로 평가되어야 하는 중요한 지표가 되었다. 하지만 종래의 진단법들은 대면적 플라즈마 진단에 매우 제한적이기 때문에 본 연구에서는 대면적 플라즈마의 공간균일도 평가를 위해 플라즈마의 방출광 측정을 기초로 하는 진단계를 개발하였다. 플라즈마 방출광을 이용한 진단은 플라즈마에 섭동을 주지 않고 전자온도의 변화 및 공간균일도를 평가할 수 있다. 이 진단법은 두 마주보는 한쪽 면이 평평한 볼록렌즈(plano-convex lens)로 이루어진 수광시스템과 역변환 알고리즘을 통해 선 적분된 방출광으로부터 플라즈마 방출광의 국지적 정보를 측정하는 것이다. 플라즈마와 같이 크기가 큰 광원의 경우 렌즈 광학계에서 필연적으로 수반되는 선적분된(chord-integrated) 방출광을 제거하기 위해 구조에 따른 시스템 함수를 이용한 푸리에 변환 알고리즘을 개발하였고, 이를 통해 렌즈 초점거리의 정확한 방출광 세기만 재구성하였다. 이러한 재구성 방법을 이용하여 렌즈의 거리를 움직이며 대면적 플라즈마의 방출광 분포측정을 수행하였고, 이에 대한 결과를 발표하고자 한다.