• 대한수의학회지
• /
• 제10권2호
• /
• pp.73-80
• /
• 1970

This report summarized the results of the post-mortem diagnosis oil the 1,785 fowl live and dead during the calender year of 1966 to 1968. The disease incidences in order were; leucosis complex(21.9%) newcastle disease (10.4%), coccidiosis (6.6%) and mismanagement(3.9%). There were also a number of other diseases common to tb,e poultry flocks such as avian mycoplasmosis, pullorum disease and, nutritional disorder etc.

• Preventive Nutrition and Food Science
• /
• 제1권1호
• /
• pp.127-133
• /
• 1996

The development of high resolution capillary columns and a large variety of different detectors led to a strong position of gas chromatography in instrumental analysis. Every effort has been made to solve sophisticated separation problems by column switching. Nowadays, several systems are commercially available for this purpose. The principle and the capabilities of multidimensional gas chromatography(MDGC) are illustrated by different applications in the field of modern flavor and essential oil research.

• 한국응용과학기술학회지
• /
• 제32권2호
• /
• pp.194-201
• /
• 2015

자동차용 엔진오일은 특성향상을 목적으로 꾸준히 발전되어 왔으며 특히, 극악조건에서 사용되는 엔진오일의 경우, 보다 높은 효과를 발휘하기 위하여 다양한 연구가 진행되어 왔다. 하지만 경제적 측면에서 윤활기유의 개발에는 한계가 있었으며 이를 보완하기 위한 방안으로 다양한 첨가제가 개발 되어왔다. 하지만 무차별적인 첨가제 사용은 환경적 측면에 많은 문제점을 발생시켰으며 이를 제도화하기 위하여 국가별 품질기준을 제정하였다. 따라서 국내 자동차용 엔진오일의 물리 화학적 특성 분석을 통하여 다양한 환경적 영향성을 검토하고자 한다.

• 한국산학기술학회논문지
• /
• 제10권12호
• /
• pp.3761-3767
• /
• 2009

산업단지에서 발생하는 액상폐기물(폐유와 폐유기용제)을 고온반응기에서(온도 $1,250{\sim}1,400^{\circ}C$, 압력 1기압) 연소시키면서 연소 특성, 유해물질 분해정도 및 연소 후 배출가스 특성 등을 살펴보았다. 산소와 폐기물의 질량비($O_2$/waste mass fraction)가 1.53 이하로 줄어들 때 반응기는 산화분위기에서 환원분위기로 전환되었고 연소 후 배출가스는 NOx 배출량이 감소하고 합성가스의 발생비율이 증가하였으며 BTEX류는 99.99%이상 분해되는 것으로 나타났다. 본 연구에서 제안한 시스템 및 조업조건 하에서 고농도의 액상폐기물(폐유와 폐유기용제)을 처리한 결과 미량 오염물질의 배출농도는 매우 낮은 값을 보여 액상폐기물의 처리에 적합한 것으로 판단되며 또한 연소 후 합성가스도연료로 활용할 수 있을 것으로 사료된다.

• 공업화학
• /
• 제10권6호
• /
• pp.809-813
• /
• 1999

D상 유화법을 적용하고 상도를 이용하여 유화메커니즘을 설명하였다. D상 유화작용은 등방성 계면활성제 용액의 형성과 함께 시작되며 계면활성제 용액에 octamethyl cyclotetrasiloxane(OMCS)의 분산으로 계면활성제중 오일(O/D) 겔 유화물의 형성에 의해 진행된다. 폴리올은 이 실험목적상 필수성분이다. 폴리올의 기능을 이해하기 위해 비이온 계면활성제/오일/물/폴리올계의 용액거동을 폴리옥시에틸렌올레일에테르/OMCS/프로필렌글리콜(PG)의 수용액인 3성분의 상도를 이용하여 조사하였다. 등방성 계면활성제상에서 오일의 용해도는 PG를 가함에 따라 증가하였다. D상 유화물은 OMCS의 농도가 70~90% 범위에서와 계면장력이 2.0~3.0 dyne/cm 범위에서만 형성되었으며, D상 유화물은 $10{\mu}m$ 정도 크기의 균일한 구상으로 O/W 형이었다.

• 대한본초학회지
• /
• 제32권1호
• /
• pp.75-81
• /
• 2017

Objectives : The present study was designed to investigate effects of mixed extracts (9:1, v/v) of Hwangryunhaedoktang, Chamaecyparis obtusa essential oil. We evaluated the antimicrobial and antioxidant activity by manufacturing mixed extracts as the materials for functional medicinal herb cosmetics. Methods : We performed antimicrobial were tested microbes (Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Candida albicans, Propionibacterium acnes) by disc diffusion method and measure clear zone. Antioxidant activities were measured by DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity. Results : Antimicrobial activities of mixed extracts against S. epidermideis, P. acnes, S. aureus, E. coli, and Candida. A were $10.9{\pm}3.0mm$, $16.9{\pm}2.0mm$, $9.2{\pm}2.0mm$, $10.3{\pm}1.0mm$, $11.8{\pm}3.0mm$ respectively. The Chamaecyparis obtusa essential oil had the highest antimicrobial activities against S. epidermideis, P. acnes, S. aureus, E. coli, and Candia. A and clear zone of microbes ware $16.7{\pm}3.0mm$, $28.8{\pm}0.2mm$, $15.9{\pm}2.0mm$, $11.5{\pm}1.0mm$, $16.3{\pm}3.0mm$. Hwangryunhaedoktang extract showed antimicrobial activity but only P. acnes and S. aureus The antioxidant activities of the mixed extracts were tested through the evaluation of DPPH radical scavenging activity. The 100 % mixed extracts were found to have 90 % DPPH radical scavenging activity. The mixed extracts was presented similar antioxidant activities compared with that of ascorbic acid. As a result, A mixture extract is expected to have antimicrobial effects and free radical scavenging activity was found. Conclusions : Accordingly, It can be concluded that mixed extracts has the potential to cosmetic material.

• Environmental Analysis Health and Toxicology
• /
• 제27권
• /
• pp.8.1-8.10
• /
• 2012

Objectives: The goal was to model and quantify the atmospheric concentrations of volatile organic compounds (VOCs) as the result of the Hebei Spirit oil spill, and to predict whether the exposure levels were abnormally high or not. Methods: We developed a model for calculating the airborne concentration of VOCs that are produced in an oil spill accident. The model was applied to a practical situation, namely the Hebei Spirit oil spill. The accuracy of the model was verified by comparing the results with previous observation data. The concentrations were compared with the currently used air quality standards. Results: Evaporation was found to be 10- to 1,000-fold higher than the emissions produced from a surrounding industrial complex. The modeled concentrations for benzene failed to meet current labor environmental standards, and the concentration of benzene, toluene, orthometa- para-xylene were higher than the values specified by air quality standards and guideline values on the ocean. The concentrations of total VOCs were much higher than indoor environmental criteria for the entire Taean area for a few days. Conclusions: The extent of airborne exposure was clearly not the same as that for normal conditions.

• Earthquakes and Structures
• /
• 제20권1호
• /
• pp.109-122
• /
• 2021

Significant progress in the oil and gas industry advances the application of pipeline into an intelligent era, which poses rigorous requirements on pipeline safety, reliability, and maintainability, especially when crossing seismic zones. In general, strike-slip faults are prone to induce large deformation leading to local buckling and global rupture eventually. To evaluate the performance and safety of pipelines in this situation, numerical simulations are proved to be a relatively accurate and reliable technique based on the built-in physical models and advanced grid technology. However, the computational cost is prohibitive, so one has to wait for a long time to attain a calculation result for complex large-scale pipelines. In this manuscript, an efficient and accurate surrogate model based on machine learning is proposed for strain demand prediction of buried X80 pipelines subjected to strike-slip faults. Specifically, the support vector regression model serves as a surrogate model to learn the high-dimensional nonlinear relationship which maps multiple input variables, including pipe geometries, internal pressures, and strike-slip displacements, to output variables (namely tensile strains and compressive strains). The effectiveness and efficiency of the proposed method are validated by numerical studies considering different effects caused by structural sizes, internal pressure, and strike-slip movements.

• 자원환경지질
• /
• 제33권5호
• /
• pp.379-389
• /
• 2000

This study was focused on the investigation for the heavy metal contamination of soils derived from Yoecheon Industrial Complex in Chonnam Province. Total 201 soil samples including farmland, paddy, forest and playground soils were collected, extracted by 0.1N HCl and analyzed for Cd, Cu, Cr, Fe, Mn and Zn using AAS. Most pH values in soils were weak acidic ranges of 4-6, while some of them were over 8.0. Concentrations of Cd, Cu, Fe and Zn in the soils tend to be relatively high around the Au-Ag mine area, railroad stations and oil station, however, those of Cr, Mn and Pb show high at the northside of Pohang Steel Co (POSCO). Cadmium-Zn couples, and Cd-Zn and Zn-Cr couples have relatively good correlations in the farmland soils and paddy soils, respectively. Concentrations of Cd, Fe and Zn with depth tend to be higher in the top soils than in the bottom soils, but those of Cu and Pb do not show regular variations with depth.

• Korean Chemical Engineering Research
• /
• 제45권1호
• /
• pp.25-31
• /
• 2007

석유화학단지내에서 석유화학공장과 정유공장과 같은 산업현장에서는 상당량의 수소가 부산물로 발생되고 있으나, 이는 대부분 자체적으로 연료로 사용되고 있다. 그러나 연료로 사용되는 상당량의 수소를 에너지원의 원료나 기타 공정의 원료로 재활용할 경우, 현재보다 수소의 가치를 높여서 사용할 수 있다. 본 연구에서는 석유화학단지내 공장간 수소 재활용 네트워크를 설계하였다. 수소 핀치 분석을 통하여 교환망 구성에 필요한 최소의 수소 요구 및 정제량을 파악하고, 네트워크 구성에 필요한 비용과 기타 제약 조건으로 최적화 문제를 구성하여 공급처(source)와 수요처(sink) 공장간에 최적으로 수소를 재활용하기 위한 네트워크를 설계하였다.