• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2001년도 ICCAS
• /
• pp.100.3-100
• /
• 2001

This article deals with the development of a mathematical model for the finishing polycarbonate polymerization process using a horizontal rotating disk-ring reactor with counter-current gas sweeping and the performance analysis of the reactor system by using the model. Here we intend to propose a model describing the reactor system consisting of two phases, in which by-product phenol is removed from the polymer of high molecular weight compatible with the products of commercial grades. The vapor phase is represented by a tanks-ln-series model while the polymer melt phase is regarded as a plug flow reactor.

• 한국가시화정보학회지
• /
• 제17권3호
• /
• pp.24-31
• /
• 2019

Recently, an air-lift bio-reactor operated by micro bubbles has been utilized to product hydrogen fuel. To enhance the performance, characteristics of hydrodynamics inside the bio-reactor were analyzed using a numerical simulation for two-phase flow. An Eulerian model was employed for both of liquid and gas phases. The standard k-ε model was used for turbulence induced by micro bubbles. A Population Balance Model was employed to consider size distribution of bubbles. A hollow cylinder was introduced at the center of the reactor to reduce a dead area which disturbs circulation of CO bubbles. An appropriate diameter of the draft tube and hollow cylinder were optimized for better performance of the bio-reactor. The optimum model could be obtained when the cross-sectional area ratio of the hollow cylinder to the reactor, and the width ratio of the riser to the downcomer approached 0.4 and 3.5, respectively. Consequently, it is expected that the optimum model could enhance the performance of the bio-reactor with the homogeneous distribution and higher density of CO, and more effective mixing.

• 한국식생활문화학회지
• /
• 제10권1호
• /
• pp.35-44
• /
• 1995

A hazard analysis which included watching operations, measuring temperatures of foods throughout preparation and display, and sampling and testing for microorganisms of total plate counts and coliform bacteria was conducted in various phases of product flow of Korean soups (Galbitang, Sullungtang, Jangkuk) prepared at Korean restaurants. Cooked foods were sometimes held at room temperature long enough to permit multiplication of bacteria that might have been present. This was confirmed by the finding of large numbers of aerobic mesophilic colonies ($10^6$) in samples of such foods after handling and holding for several hours before served. These bacteria decreased down to $10^1{\sim}10^2$ while the contaminated Tang were served. And internal temperature of Tang served was approximately $70^{\circ}C$. Critical control points identified were, pre-preparation, handling after cooking and holding on display. Guidelines were suggested for effective quality control of Tang (Korean soups) production. Handlers of these foods need to be informed of the hazards and appropriate preventive measures.

• 한국식품조리과학회지
• /
• 제24권5호
• /
• pp.652-664
• /
• 2008

In this study, a Hazard Analysis Critical Control Point (HACCP) plan was developed for the sanitary mass production of commercial Korean rice cake products (Gaepidduk, Injulmi, and Julpyon). The microbiological properties of manufacturing flow were evaluated in order to develop the HACCP Plan. The moisture contents of the rice cakes ranged between 36.2${\sim}$55.3%, whereas the water activity of all samples ranged between 0.954${\sim}$1.0. Microorganisms testing was conducted during various phases of the product flow of Korean rice cake preparation, and included assessments of food equipment, work environment, and cooking employees on a small scale. During the manufacture of Injulmi, Julpyon and Gaepidduk, CCPs were purchasing & storage, steaming and cooling, molding, and holding in the A and B manufactories. At the critical limit of CCPs, storage was conducted below at $5^{\circ}C$ in soybean powder, oil, and paste with redbeans. The steaming process was conducted above at $99^{\circ}C$ for 40 min. Cooling and holding processes were conducted for 2 hours below at $15^{\circ}C$. The molding process included sanitary education for foodhandlers and training for operators. Thus, certain prerequisite programs had to be implemented prior to the implementation of the HACCP system. High levels of bacterial contamination were detected in the aprons worn to work by some employees. Additionally, periodic sanitary education for foodhandlers and training for operators or managers was required. Cross contamination by materials was expected at the place where materials were processed or stored.

• 한국식생활문화학회지
• /
• 제10권1호
• /
• pp.67-74
• /
• 1995

This study researched microbial change of quality according to the various phases of product flow of cooked pea and rice, cold cucumber and seaweed soup, soybean sprouts japchae feeding urban type of a commissary school and a satellite school in Daejeon area, also it suggested the possibility that the central commissary foodservice system can be established and utilized more developmental to identify its food of variation of temperature and state of safety unitl 3 hours after cooking for the case of delay of distribution and holding because of the satellite school of geographical location and traffic problem. The critical Control Points identified for each category of menu items were: Boiled pea and rice: inadequate distribution, holding and storing before assembly; Cold cucumber and seaweed soup: pre-preparation and post-preparation after cooking; Soybean sprouts japchae: Pre-preparation, post-preparation and storing. As the result of observation of the variation of temperature and microbial safety according to the delay of distribution and holding for each food, all of them were relatively safe until 3 hours after cooking, but cold cucumber and seaweed soup being stored for 3 hours, the value of E. coli is $10^3$ CFU/g. The variation of temperature was more extreme in soybean sprouts japchae than cooked pea and rice and cold cucumber and seaweed soup. It was proved that the stainless container was excellent and that adequate holding container should be used.

• 한국식품조리과학회지
• /
• 제13권5호
• /
• pp.592-601
• /
• 1997

The purposes of this study were to develop Hazard Analysis Critical Control Point-based standardized recipe applicable to cook/chilled soy sauceglazed mackerel and to evaluate the qualities related to the product flow of this item. After conducting experimental cooking, preliminary test, and analysis of recipes, critical control points were identified, control methods were determined, and HACCP-based recipe was standardized. At each critical control point, time-temperature profile was recorded and microbiological analysis (total aerobic plate counts, psychrotrophic plate count, coliform, and fecal coliform count), chemical analysis (pH, acid value and volatile based nitrogen (VBN)) and sensory evaluation of the item were done. Time-temperature data showed that the time the menu item had passed through temperature danger zone (5∼60$^{\circ}C$) during all phases was 60 min. At rapid cooling, but after cooling at room temperature, the temperature of this menu item did not drop below the ambient temperature. The results of microbiological test were negative throughout all phases following cooking and the results of chemical analysis did not change significantly in terms of storage periods except for VBN which increased on 7th day significantly(p<0.05). After steam/convection oven reheating and microwave oven reheating, the sensory score of the only appearance decreased significantly related to the storage time of overall quality profiles. But significant differences were not detected according to two reheating methods. In conclusion, this HACCP-based recipe was considered as an effective tool for assuring microbial as well as sensory quality of this cook/chilled item.

• 디자인학연구
• /
• 제12권4호
• /
• pp.294-303
• /
• 1999

최근 들어 컴퓨터 환경의 비약적인 발전에 따라 디자인 과정도 크게 변화하고 있다. 자동차나 지게차 등과 같은 운송기기의 디자인이나, 작업장의 디자인의 경우 초기 디자인 과정중에서 레이아웃을 결정하고 인체 공학적인 데이터를 추출함에 있어서 설문이나 2D의 라인드로잉에 의존해 오고 있다. 이러한 방법의 문제점은 신뢰성이 많이 떨어질 뿐만 아니라 2D 마네킨을 사용하므로써 실제 사각으로 움직이는 인간 몸체의 움직임이 고려되지 못하며, 움직임 범위가 확정된다 하더라도 그 범위내에서의 움직임에 대한 인체의 피로도나 안락도 정도에 관해서는 전혀 측정할 수가 없었다. 컴퓨터 하드웨어와 소프트웨어의 비약적인 발전은 일반 생활환경 뿐 아니라 디자인환경에서도 가상환경 (Virtual Environment) 이라는 큰 흐름을 가져 왔다. 특히 기존의 컴퓨터를 응용한 디자인에서는 Visualization이나, CAD&CAM을 통한 데이터의 교환이 주된 관심사였으나, 최근 들어 빠르게 소개되고 있는 가상환경에서는 디자인초기단계에서 디자인 레이아웃 결정 뿐 아니라 사용자가 느끼게 되는 미세한 감각까지도 데이터화할 수 있게되었다. 본 연구에서는 이와 같이 디자인에서 사용할 수 있는 가상환경의 일반적인 특성를 밝히고, 초기 디자인 과정에서 디지털화된 환경의 이용가능성을 모색하였다. 이러한 연구는 실제 지게차 디자인의 사례를 통하여 살펴보았으며 이 사례연구를 통하여 디자이너가 활용할 수 있는 가능성과 문제점이 무엇인지 밝혔다. 마지막으로 3차원 가상인간의 적용을 통해 초기 디자인 단계에서 새롭게 적용될 수 있는 디지털화 디자인 작업의 잇점에 대하여 논의 하였다.

• Journal of Nutrition and Health
• /
• 제18권4호
• /
• pp.283-292
• /
• 1985

대학 급식 시설의 위생 실태를 평가하기 위해서 오뎅국의 생산 과정을 통한 소요시간 및 온도상태 측정 pH 및 Aw측정, 미생물 검사를 실시하여 HACCP model에 의해 분석, 평가한 결과는 다음과 같다. 1 )소요시간 및 온도상태 측정 결과. 재료들의 조리후 실온방치 단계와 국물의 보온단계에서 철저한 관리가 요구된다. 2 ) pH및 Aw측정 결과, 대부분의 단계가 미생물 증식에 적합한 조건이었다. 3 )음식에 대한 미생물 분석 결과, 재료들의 미생물적 품질이 대체로 낮았다. 또한 조리후 급식전 보관단계에서 장시간 실온에 방치되므로 미생물의 오염 및 증식 기회가 많았다. 4 ) 오뎅국 생산에 사용되는 기구, 설비, 용품 및 용기에 대한 미생물 분석 결과 뚝배기, 장갑, 행주와 도마에 대한 즉각적인 시정이 요구된다. 5 ) 이상에서 오뎅국 생산 단계에서의 critical control points는 재료, 전처리, 후처리 및 급식전 보관단계로 지적되었다.

• 한국식품위생안전성학회지
• /
• 제3권3호
• /
• pp.117-129
• /
• 1988

서울·경기지역 도시락 제조업체의 작업환경 및 도시락의 부식인 동태전 생산과정의 위생상태를 위생 점검표 및 미생물 검사를 토대로 분석, 평가한 결과는 다음과 같다. 1) 주방의 위생 상태는 향상 가능성이 있는 보통상태로 나타났고, 종업원의 위생습관은 대·중규모 업체는 향상가능성이 있는 보통상태이었으며 소규모 업체는 위험요인이 존재하는 불량상태로 나타났다. 2) 도시락 제조업체별로 동태전의 생산과정에서 원재료와 전처리 후의 재료는 미생물적인 품질이 낮았다. 3) 조사결과 조리한 음식을 실온에서 보관하는 단계와 출고하기 전까지 조합하고 포장하는 동안 실온에서 방치하는 단계는 온도 및 소요시간이 미생물 증식에 적합한 환경이 되는 위험한 단계이었다. 4) 각 업체에서 사용하는 칼, 도마 ,행주의 미생물 수치가 높아 cross contamination의 가능성이 높았다. 5) 도시락 제조업체에서 동태전의 생산 과정중의 critical control points 는 전처리단계 , 보관단계, 조합과 포장단계 및 기구로 지적되었다.