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공정시스템, 이동현상, 화학공정안정 : 열통합 증류 공정의 상세 동적 모델링 및 모사
박병학 ( Byung Hak Park ),이희승 ( Hee Sung Lee ),문일 ( Il Moon ) 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.1
A rigorous dynamic modeling and dynamic simulation are performed to find the dynamic behaviour of a distillation column model including continuous/discrete variables, considering material balances, heat balances, nonlinear hydraulic equations and themodynamic correlations in all equipments. Target process of this study is a distillation column aimed at separating benzene and toluene. Through dynamic modeling, 1,062 differential algebraic equations are acquired. Numerical solutions of dynamic behaviour such as pressure, temperature, fraction and molar flow rate in liquid and vapor phase. The feature in this study is to compare the energy consumption of a conventional distillation column with that of a heat integrated distillation column using dynamic simulation method. This study verifies energy efficiency through dynamic simulation in series of start-up of processes. There are some verifications of a heat integrated distilation column in view of steady state simulation but no verification in view of dynamic simulation. Also, this study considers operating procedures of the process in dynamic simulation through modeling of all equipments such as reboilers, refluxdrums. pumps, valves, digital PI controllers etc.
학생운동선수의 외과수술에 대한 지각된 위험과 의료기관 선택의 관계
박병학(Park, Byung-Hak),김기섭(Kim, Ki-Sup) 한국체육과학회 2016 한국체육과학회지 Vol.25 No.5
The purpose of this study is to investigate a relationship between perceived risks of surgical operation and choices over medical clinic of student athletes. To secure the preliminary data of this study, this study surveyed 400 1st, 2nd, 3rd, and 4th grade physical education major students of K, Y, and D University located in metropolitan area. Among 400 students, survey data of 312 students excluding inappropriate or incomplete answer sheets were adopted. The collected questionnaire was analyzed using a statistics program, the SPSS Version 18.0 Program. This study conducted correlation analysis and multiple regression analysis to investigate a relationship between perceived risks of surgical operation and choices over medical clinic of student athletes. Specific research results obtained through the research process are as follows. Perceived risks made significant effect partly on subfactors of choices over medical clinic as reputation, internal physical environment, service quality, and external physical environment. It was identified that reputation of choices over medical clinic makes negative effect on psychological risk and financial risk, and service quality makes negative effect on psychological risk and performance risk and positive effect on financial risk. External physical environment made negative effect on financial risk.
박병학(Byung-Hak Park),채경연(Kyung-Yeon Chae),홍진숙(Jin-Sook Hong) 동아시아식생활학회 2008 동아시아식생활학회지 Vol.18 No.2
The aim of this study was to determine the optimal cooking conditions in preparing jujube concentrates using various boiling times (5, 10, 15, 20 hours). The moisture contents of the concentrate samples ranged from 38.86 to 42.36%. Crude protein content was highest in the 15 hr-boiled concentrate, crude fat was highest in the 20 hr-boiled concentrate and both the 15 and 20 hr boiled concentrates had high crude fiber contents. There were no differences in color L- and a-values by boiling time; however, the b-value decreased with increasing boiling time. The pH levels of the concentrates ranged from 5.24 to 5.27, and the brix level increased with increasing boiling time. Glucose was the primary of free sugar in the concentrates and its highest level was 102.3 μM in the 20 hr-boiled concentrate. The 15 hr-boiled concentrate had the highest electron donating ability to 46.68%. The total polyphenol contents of the concentrates ranged from 21.53 to 24.56%, in which the 15-boiled concentrate had the highest level (24.56%). In the sensory evaluation, the 15-hr-boiled concentrate again performed well, showing the highest overall acceptability scores. From these results, 15 hrs was the optimal boiling time for preparing jujube concentrate in terms of obtaining functional compounds and overall product acceptability.
유한요소법에 의한 소형선박용 엔진의 피스톤에 대한 온도해석
김옥삼(Ok Sam KIM),박병학(Byung Hak PARK) 전남대학교 수산과학연구소 1994 수산과학연구소논문집 Vol.3 No.-
The analysis of temperature distribution is substantilly important in optimal design of engine. In this study, temperature analysis of the aluminum alloy piston of small sized ship during high speed driving (3000rpm) is analyzed the two-dimensional heat conduction problem using finite element method(FEM). Formulation of FEM based weighted residural method were presented for the analysis of the two dimentional axis symmetric conditions. And the pre and post-processor are composed for the easy decision of result and the exact analysis, and outcomes are plotted by using AutoCAD and AutoLISP. The consequence obtained in this study are summurrized as follows. In temperature distribution analysis, maximum temperature was shown in the centre of the crown, and the great temperature gradient was occurred on the wall of the piston.
Young-Woong Song(송영웅),Jehong Im(임제홍),Min-Young Kim(김민영),Ho-Sung Kim(김호성),Youngsun Hong(홍영선),Byung Hak Park(박병학),Dong Yoon Lee(이동윤),Jae Heon Lee(이재헌),Jaekook Kim(김재국),Jinsub Lim(임진섭) 한국전지학회 2022 한국전지학회지 Vol.2 No.1
최근, 기후변화의 영향으로 재생가능 자원 개발 문제가 큰 주목을 받고 있다. 리튬이온배터리(LIBs)는 화석 연료의 대안으로 제공되어 자동차 산업에서 특히 주목을 받고 있다. 그러나 LIB가 보여주는 배터리 수명과 해당 주행거리에 한계가 있다. LIB 내의 열 관리는 배터리 수명을 결정하는 중요한 요소이다. 본 연구에서는 수동적 열 관리 시스템을 제공하는 상변이 물질(PCM)을 다양한 조건에서 분석하였다. PCM으로 덮인 LIB에서 얻은 결과는 덮지 않은 참조 셀에서 얻은 결과와 비교하였다. PCM은 온도를 조절하여 셀에 의해 나타나는 열화를 감소시킬 수 있는 것으로 나타났다. 따라서 PCM은 LIB 성능의 개선을 촉진할 수 있음을 보여준다. At present, the issue of renewable resource development has attracted significant attention owing to the effects of climate change. Lithium-ion batteries (LIBs) have received particular attention within the automotive industry as they provide a viable fossil fuel alternative. However, the commercialization of electric vehicles is currently limited by the battery life, and corresponding mileage, exhibited by LIBs. Thermal management within the LIB is a significant factor in determining the lifetime of the battery. In this study, a phase change material (PCM), which provides a passive thermal management system, was analyzed under various conditions. The results obtained from the PCM-covered LIB were compared with those obtained from a reference cell without the PCM covering. It was shown that the PCM can regulate the cell temperature, thereby reducing the deterioration exhibited by the cell. This PCM characteristic can, therefore, facilitate an improvement in the LIB performance.