• 한국수소및신에너지학회논문집
• /
• 제31권5호
• /
• pp.436-443
• /
• 2020

The performance prediction model of a solid oxide fuel cell stack has been developed using deep neural network technique, one of the machine learning methods. The machine learning has been received much interest in various fields, including energy system mo- deling. Using machine learning technique can save time and cost requried in developing an energy system model being compared to the conventional method, that is a combination of a mathematical modeling and an experimental validation. Results reveal that the mean average percent error, root mean square error, and coefficient of determination (R2) range 1.7515, 0.1342, 0.8597, repectively, in maximum. To improve the predictability of the model, the pre-processing is effective and interpolative machine learning and application is more accurate than the extrapolative cases.

• 기본간호학회지
• /
• 제6권3호
• /
• pp.359-368
• /
• 1999

Background : The purpose of this study was to determine whether cleansing the perineum and urethral meatus and using midstream urine affect the rate of bacterial contamination of urine specimens, and to determine the optimum urine collection method. We studied 41 asymptomatic healthy nursing school students. Women who were menstruating were not excluded from this study. Method : The first and midstream urine samples were collected during consecutive urinationsby each woman. The first sample was not a clean-catch specimen, and the second one was a clean-catch specimen. Both specimens were studied by urinalysis and bacterial culture with standard methods. Results : 41 women met the study criteria and 39 successfully completed the study. None of the urine cultures were positive. 68.3% of the non clean-catch first urine cultures, 53.7% of the non clean-catch midstream cultures, 33.3% of the first clean-catch urine culteres and 30.8% of the midstream clean-catch urine were found to be contaminated. There was a significant difference in the bacterial contamination rates between the first and midstream urine, and the clean-catch and non clean-catch urine(p=0.035, p =0.001 respectively). On urinalysis, 7.3% of the non clean-catch first urine, 7.3% of the non clean-catch midstream urine, 2.6% of the clean-catch first urine and 2.6% of clean-catch midstream urine were found to be above grade 2. Conclusions : According to our results, the bacterial contamination rate was the lowest in midstream and clean catch urine specimens. Threrfore it is recommended that the midstream clean-catch technique is the standard practice for collecting urine specimens for bacterial culture in women.

• 대한안전경영과학회:학술대회논문집
• /
• 대한안전경영과학회 2006년도 추계공동학술대회
• /
• pp.325-336
• /
• 2006

This research analyzes clean room major fire prevention standard of clean Room (FM, IRI, and NFPA Code), the structure of Performance-Based Fire Safety Design (PBD) applied the korean fire industry situation. Performance-Based Fire Safety can operate effectively the performance of fire protection equipment & building design, so the fitness of fire safety system can be embodied by operating this. moreover, cost to be consume fire safety of real building can reduce and Performance-Based Fire Safety is considered to important technique in fire protection field. A fire in a clean room may cause a serious loss by spreading smoke particles. We will be investigated by using a computational fluid dynamics, for loss prevention by smoke spreading from one fire area to another for clean room and compared the Performance-Based Fire Safety Design with the prescriptive code design. The methodology of fire safety performance-based fire safety design and guarantee of many kinds design skill of fire system and developing design procedure will be very serious one in order to improve efficiency of domestic system. Therefore, This research will be contributing to secure safety of clean room and to set up the performance-based fire safety design in Korea by regulation for the performance-based fire safety design effectively.

• 대한안전경영과학회지
• /
• 제8권5호
• /
• pp.211-229
• /
• 2006

This research analyzes clean room major fire prevention standard of clean Room(FM, IRI, and NFPA Code), the structure of Performance-Based Fire Safety Design(PBD) applied the korean fire industry situation. Performance-Based Fire Safety can operate effectively the performance of fire protection equipment & building design, so the fitness of fire safety system can be embodied by operating this. moreover, cost to be consume fire safety of real building can reduce and Performance-Based Fire Safety is considered to important technique in fire protection field. A fire in a clean room may cause a serious loss by spreading smoke particles. We will be investigated by using a computational fluid dynamics, for loss prevention by smoke spreading from one fire area to another for clean room and compared the Performance-Based Fire Safety Design with the prescriptive code design. The methodology of fire safety performance-based fire safety design and guarantee of many kinds design skill of fire system and developing design procedure will be very serious one in order to improve efficiency of domestic system. Therefore, This research will be contributing to secure safety of clean room and to set up the performance-based fire safety design in Korea by regulation for the performance-based fire safety design effectively.

• 청정기술
• /
• 제3권2호
• /
• pp.31-33
• /
• 1997

Nitrate contamination in surface water and ground water have increased in Korea. This trend has raised concern because nitrates caused methemoglobinemia in infants. To remove nitrates from waters, various purification processes including ion-exchange, biological denitrification, and chemical denitrification are currently in use for the treatment of water. However, little economically advantageous process exists for the industrial scale treatment of effluents highly polluted with nitrates. A new process has been developed for nitrate and other salts removal from polluted waters. Alumina cement and lime served as precipitating agents to remove nitrate with stirring at basic pH. Decreasing alumina content in alumina cement result in a increasing in nitrate removal yield. Stable removal of nitrate(1000mg/L) was readily achieved by two-stage removal process.

• 한국표면공학회지
• /
• 제48권5호
• /
• pp.194-198
• /
• 2015

A blade-abrading method was newly developed for the preparation of clean Mg alloy surface and reported for the first time in detail in this paper. The blade-abrading method includes abrading of the Mg alloy surface with a sharp blade or knife to remove the surface oxide and contaminants on the skin of Mg alloys mechanically, thereby providing very clean surface of Mg alloys. The clean surface prepared by the blade-abrading method in the air was found to be covered with thin and dense air-formed oxide films. Based on the experimental results obtained in this work, it is concluded that the newly developed blade-abrading technique is a very simple and useful pretreatment method which can provide clean and well-defined surface for the following surface treatments.

• 기계와재료
• /
• 제10권3호통권37호
• /
• pp.71-77
• /
• 1998

• 한국산학기술학회:학술대회논문집
• /
• 한국산학기술학회 2000년도 춘계학술대회
• /
• pp.56-56
• /
• 2000

• Corrosion Science and Technology
• /
• 제21권5호
• /
• pp.327-339
• /
• 2022

The water-jet technique started by Bridgman can cut metal and alloys without harmful gas and fume. However, while this technique is convenient to cut metals and alloys, in the case of coated pipe, water jet induces the degradation of coatings on the pipes, and may facilitate structural failure, leakage, and loss of products. While there are many reports on the effect of water jet on cut metals and the damage of metallic materials, research on the effect of water impingement on the epoxy coatings has been little studied. In this work, we therefore control the velocity of water jet, distance between nozzle and specimen, and water temperature, and discuss the effect of water impingement on the epoxy coatings. Increasing water velocity and water temperature and reducing nozzle distance increased the degradation rates of three epoxy coatings were increased. Among three test parameters - water velocity, nozzle distance and water temperature, water temperature was relatively effective to increase the degradation rate of epoxy coatings.

• 청정기술
• /
• 제3권2호
• /
• pp.87-93
• /
• 1997

본 실험은 알루미나 시멘트와 산화칼슘을 이용해 염기성 조건에서 질산염을 침전시킴으로써 오염수를 처리하는 공정에 관한 것이다. 시중에 시판되고 있는 알루미나 시멘트 중 알루미나 함량이 낮은 시멘트가 높은 질산염 제거를 보였다. 알루미늄과 칼슘의 성분비는 침전반응에 가장 중요한 요소임을 알 수 있었다. 고농도의 질산염 폐수의 처리를 위해 다단계의 침전반응이 효과적이었다. 질산염 뿐만 아니라 황산, 인산 및 염소의 제거에도 침전반응에 의한 제거가 가능하였다. 반응 후에 탄산나트륨의 첨가와 산을 이용한 중화를 포함한 후처리로 처리수내에 용출된 알루미늄과 칼슘의 제거가 가능하였다.