• Journal of the Korean Society of Food Science and Nutrition
• /
• v.37 no.8
• /
• pp.1049-1057
• /
• 2008

The purpose of this study was to microbiologically evaluate common foods and preparation processes in three large (over 100 pyeong) western-style restaurants in Daegu. Microbiological testing was conducted for pathogens including E. coli, Salmonella spp., Listeria monocytogenes, Staphylococcus aureus, E. coli O157:H7, Vibrio parahaemolyticus, and Bacillus cereus, as well as total plate count and coliforms. Food samples selected for testing represent common menu items and preparation processes. These samples included: 1) hamburger steak (cooking process), 2) mashed potatoes (reheating process), and 3) salad (non-heating process). The results showed that E. coli and S. aureus were detected in the raw ground beef used to prepare hamburger steak, but they were not detected after cooking at $82{\sim}86^{\circ}C$, 10 min. Microbiological quality of the mashed potatoes was better after reheating than during storage in a refrigerator after cooking. Total plate count and coliforms increased, and E. coli was detected in the salad ingredients stored in the refrigerator before serving. In order to serve foods of good microbiological safety and quality in western-style restaurants, standard cooking and reheating temperatures must be maintained during the cooking and reheating processes, and sanitation standard operating procedures must be followed for washing and storage of non-heated and refrigerated menu items.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.465-465
• /
• 2014

증식블랑켓모듈(TBM, Test Blanket Module)을 개발하여 왔다. 이 두 증식블랑켓모듈은 모두 헬륨냉각을 기반으로 개발 되어왔으며 이에 따라, 헬륨순환기, 헬륨히터 및 헬륨열교환기 등에 대한 기본적인 연구가 수행되었다. 이후 2012년 고체형 증식블랑켓모듈을 ITER TBM 개념으로 주도하기로 결정함에 따라, HCCR (Helium Cooled Ceramic Reflector) TBM의 보조계통인 하나인 헬륨냉각계통(HCS, Helium Cooling System)에 대한 개발이 본격적으로 이루어졌다. 한국원자력연구원에서는 HCCR TBM의 냉각성능을 만족하기 위하여 8 MPa, 1.5 kg/s 및 $300/500^{\circ}C$ (입구/출구 온도)의 운전조건을 갖는 헬륨냉각계통의 설계를 완료하였다. 설계된 헬륨냉각계통은 HCCR TBM에서 회수된 약 $450^{\circ}C$의 헬륨을 열회수기(recuperator)기와 냉각기를 통해 상온으로 냉각시킨 후, 필터를 통해 헬륨을 여과시킨다. 여과된 헬륨은 헬륨순환기에 의해 가압되어 열회수기를 다시 지나 $300^{\circ}C$ 이상으로 가열된다. 가열된 헬륨은 열회수기를 지나지 않는 상온의 헬륨과 혼합되어 최종적으로 HCCR TBM의 입구온도 조건인 $300^{\circ}C$로 맞추어 HCCR TBM에 공급된다. 이러한 열회수기 중심으로 '${\infty}$' 모양의 자가 교차로 설계된 헬륨냉각계통은 고온영역과 저온영역으로 냉각회로를 구분하여 순환기, 필터 및 각종 계측기의 운전온도 환경을 상온으로 유지시킬 수 있어 운전 및 유지보수 관점에서 이점이 있다. HCCR TBM의 헬륨냉각계통 설계 및 핵심 기기를 실증하고, 운전 경험을 쌓기 위하여 헬륨공급장치(HeSS, Helium Supply System)를 헬륨유량기준 1/3 규모(0.5 kg/s)로 구축하였으며, '14년까지 HeSS를 실증규모로 업그레이드 하기 위하여 80기압 환경에서 압축비 1.1, 유량 1.5 kg/s의 성능을 내는 헬륨순환기를 설치할 예정이다. 현재 구축된 1/3 규모 HeSS는 국내 구축된 전자빔 고열부하 시험 장비인 KoHLT-EB (Electron Beam)와 연계되어 HCCR TBM의 일차벽(플라즈마 대향부품)을 검증할 예정이며, 이를 통해 얻어진 열수력 DB는 현재 개발중인 핵융합로 안전해석코드인 GAMMA-FR 검증에 활용될 계획이다.

• Korean Journal of Food Science and Technology
• /
• v.27 no.3
• /
• pp.428-438
• /
• 1995

The gelatinization properties of corn and waxy corn starch doughs were examined at various moisture contents, heating temperatures and heating times. The onset temperatures of gelatinization with 1% CMC using Brabender Amylograph were $64^{\circ}C$ for both corn and waxy corn starch. In the gelatinization properties using DSC, onset temperature$(T_o)$, maximum peak temperature$(T_p)$, completion temperature$(T_c)$ and enthalpy of the corn starch were $68.15^{\circ}C,\;74.01^{\circ}C,\;85.65^{\circ}C$ and $3.2\;cal/gram$ respectively. While those of the waxy corn starch were $68.24^{\circ}C,\;75.43^{\circ}C,\;93^{\circ}C$ and $4.2\;cal/gram$ respectively. In enzymatic analysis, when the moisture content increased from 36% to 52% and heating temperature from $60^{\circ}C$ to $100^{\circ}C$, the gelatinization degree of starch dough increased from about 10% to about 62%. The gelatinization degree of waxy corn starch dough was $15{\sim}20%$ higher than that of corn starch dough under the same gelatinization conditions. The regression equations of gelatinization degree (Y) of starch dough in the range of $36{\sim}52%$ moisture content $(X_1)\;60{\sim}100^{\circ}C$ heating temperature $(X_2)\;and\;0{\sim}2.0$ min heating time $(X_3)$ were examined using response surface analysis. The regression equation of corn starch dough was: $Y=28.659+8.638\;X_}+15.675\;X_2+7.770\;X_3-1.620\;{X_1}^2+10.790\;X_1X_2-4.220\;{X_2}^2+0.510\;X_1X_3+1.980\;X_2X_3-6.850\;{X_3}^2\;(R^2=0.9714)$ and that of waxy corn starch dough was: $Y=32.617+12.535\;X_1+20.470\;X_2+8.608\;X_3+4.093\;{X_1}^2+13.550\;X_1X_2-4.467\;{X_2}^2+1.560\;X_1X_3+2.160\;X_2X_3-9.527\;{X_3}^2$\;(R^2=0.9621)$. As the moisture content, heating temperature and heating time increased, the reaction rate constant(k) of gelatinization increased. The greatest reaction rate constant was observed at initial 0.5 min heating time of 1st gelatinization stage. At the heating temperature of $90^{\circ}C$, gelatinization of starch dough was completed almost in the initial 0.5 min heating time. The reaction rate constant of waxy corn starch dough was higher than that of corn starch dough under the same gelatinization conditions. At the 52% moisture content, the regression equation between reaction rate constant(k) and heating temperature(T) for corn starch dough was $log\;k=11.1140-4.1226{\times}10^3(1/T)$ (r=-0.9520) and that of waxy corn starch dough was $log\;k=10.1195-3.7090{\times}10^3(1/T)$ (r=-0.9064).

• Korean Journal of Food Science and Technology
• /
• v.35 no.1
• /
• pp.33-37
• /
• 2003

Sensory quality of pine nut gruel was investigated to determine the effects of processing conditions on its quality. Response surface methodology was applied to investigate effects of water volume and pine nut weight ratios to rice weight and heating time on the preference of pine nut gruel in terms of color, flavor, viscosity, taste, and overall acceptance. Results showed that processing conditions did not affect the color of pine nut gruel. Viscosity and overall acceptance were affected by the ratio of water volume to rice weight and heating time. $R^2$ of response surface regression equations were 0.6954, 0.8333 (p<0.05), 0.9668 (p<0.01), 0.8664 (p<0.05), and 0.8159 (p<0.10) for color, flavor, viscosity, taste, and overall acceptance respectively. No relationship was observed between color and overall acceptance. The relationship between viscosity and overall acceptance was the highest.

• Food Science and Preservation
• /
• v.13 no.5
• /
• pp.581-588
• /
• 2006

Dynamic changes of free sugar and amino acid in the mixture of red bean paste sediment by corn syrup concentration and heating conditions were monitored. Glucose and fructose contents of red bean paste increased with an increasing blown color intensity. Amino acid content was affected by the heating temperature, increased with an increase in browning color intensify. Browning color intensity of each samples increased up to $95^{\circ}C$, but decreased above $95^{\circ}C$. This result was the same tend as changes of glucose and amino acid. The result of correlation coefficients among free sugar amino acid and browning color intensity show that increase in browning color intensity was not correlated directly with changes of free sugar and amino acid content. It seems that the contents of free sugar and amino acid resolved from saccharides and protein were much mote than contents nea for browning reaction.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.290-293
• /
• 2017

A direct-connected, continuous type combustion test facility was developed to test a supersonic combustor model used in scramjet engines. The facility requirements were determined by assuming the flight speed of Mach 5, yielding the combustor inlet flow speed of Mach 2. Also the cross-section of the supersonic combustor under test was assumed as $32mm{\times}70mm$. As a result, the facility was designed to have the flow total pressure of 548 kPaA, total temperature of 1,320 K, and flow rate of 0.776 kg/s. The facility consists of a turbo type air compressor, electric air heater, vitiation air heater and a two dimensional facility nozzle to accelerate the flow to Mach 2. Also, an oxygen supply system was added to compensate the vitiation. The exhaust de-pressurization system is not added. Designed pressure, temperature, and flow rate were verified through the test operation of the facility.

• Proceedings of the Korea Society of Environmental Toocicology Conference
• /
• 2002.10a
• /
• pp.162-162
• /
• 2002

염소소독 결과 수돗물 중에 존재하는 Dichloroacetic acid(DCAA)와 Trichloroacetic acid(TCAA)는 동물실험 결과 발암성 등 악영향을 일으키는 것으로 알려져 있다. 이러한 화합물들은 수돗물을 사용할 때 열을 가하면 그 농도가 변하게 된다. 이 연구에서는 설문조사를 통해 개인이 하루 동안에 섭취하는 수돗물의 양과 섭취패턴을 조사하고, 각 가정마다 수돗물의 농도를 측정하여 DCAA 및 TCAA에 대한 경구섭취 노출량을 평가하고자 실시하였다. 춘천에 위치하고 있는 60가정을 2002년 1월부터 2월 사이와 7월부터 8월 사이에 방문하여 수돗물을 채취하고, 주부를 대상으로 24시간 동안의 물 사용에 대한 설문을 실시하였으며, 아침 첫 소변을 회수하였다. 수돗물 및 소변 중 DCAA 및 TCAA에 대한 분석은 methyl ester 형태의 유도체를 만든 후 GC/PDECD로 분석하였다. 수돗물을 가열하면 DCAA의 농도는 증가하고, TCAA의 농도는 감소하였고, DCAA 및 TCAA의 경구 섭취량은 수돗물 중의 농도에 섭취부피와 가열시간에 따른 농도변화율을 곱하여 산출하였다. 실험 대상자들의 평균 수돗물 섭취부피는 1.7$\ell$이었고, 평균 가열시간은 10~15분이었다. 추정한 DCAA의 섭취량은 찬 수돗물만을 마시는 것을 가정한 것에 비해 182% 높았고, TCAA에 대해서는 30% 낮았다 이와 같은 결과는 우리나라 사람들의 식생활이 국이나 찌개 및 보리차 등과 같이 가열한 음식이나 음용수를 많이 섭취하기 때문이다. 그러므로 음용수 중 DCAA 및 TCAA의 인체 섭취 노출평가를 하기 위해서는 섭취한 부피뿐만 아니라 가열에 따른 농도 변화도 동시에 고려하여 야 한다.배 센타의 재고 완충역할을 수행하게 한다. 이에 따라 안전 재고 및 역 배송을 최소화 할 수 있을 뿐 아니라 미 출고로 인한 손실을 최소화하며 고객의 서비스를 일정하게 유지시킬 수 있을 것으로 기대된다.증진, 페기물 발생 억제 분야에 상당한 성공을 거두었으며, 지금도 지속적으로 유지 관리 및 미비한 부분(CAER, 등)의 향상에 노력하고 있다. Dow Korea의 수입 판매 부분에 주로 관련된 Product Stewardship 및 Distribution Code는 여러 사업부 및 여러 지역(미국, 유럽, 아시아 등)에 위치한 담당자가 관련된 까닭에 가장 복잡한 부분이어서 많은 인력과 시간을 소비하면서 노력하고 있으나 아직까지 소정의 목표에 도달하지 못했으며, 2000년 말에 모든 실행지침이 실행되도록 목표, 실행 계획 및 조직을 수정하여 노력하고 있다.lumn density at distant position from MD5 is larger than that in the (:entral region. We have deduced that this hot-core has a mass of 10sR1 which i:s about an order of magnitude larger those obtained by previous studies.previous studies.업순서들의 상관관계를 고려하여 보다 개선된 해를 구하기 위한 연구가 요구된다. 또한, 준비작업비용을 발생시키는 작업장의 작업순서결정에 대해서도 연구를 행하여, 보완작업비용과 준비비용을 고려한 GMMAL 작업순서문제를 해결하기 위한 연구가 수행되어야 할 것이다.로 이루어 져야 할 것이다.태를 보다 효율적으로 증진시킬 수 있는 대안이 마련되어져야 한다고 사료된다.$\

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.25 no.2
• /
• pp.175-186
• /
• 2023

The buffer materials in disposal hole are exposed to the decay heat from spent nuclear fuels and groundwater inflow through adjacent rockmass. Since understanding of thermal-hydro-mechanical-chemical (T-H-M-C) interaction in buffer material is crucial for predicting their long-term performance and safety of disposal repository, it is necessary to investigate the heating-hydration characteristics and consequent T-H-M-C behavior of the buffer materials under disposal conditions considering geochemical factors. In response, the Korea Atomic Energy Research Institute developed a laboratory-scale 'Lab.THMC' experiment system, which characterizes the T-H-M behavior of buffer materials under different geochemical conditions by analyzing heating-hydration process and stress changes. This technical report introduces the detail design of the Lab.THMC system, summarizes preliminary experimental results, and outlines future research plans.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.10
• /
• pp.1367-1375
• /
• 2010

In this study, optimization of the process parameters of the resistance spot welding of a sheet of aluminum-coated boron alloyed steel, 22MnB5, used in hot stamping has been performed by a Taguchi method to increase the strength of the weld joint. The process parameters selected were current, electrode force, and weld time. The heating temperature and heating time of 22MnB5 are considered to be noise factors. It was known that the variation in the thickness of the intermetallic compound layer between the aluminum-coated layer and the substrate, which influences on the formation of nugget, was generated due to the difference of diffusion reaction according to heating conditions. From the results of spot weld experiment, the optimum weld condition was determined to be when the current, electrode force, and weld time were 8kA, 4kN, and 18 cycles, respectively. The result of a test performed to verify the optimized weld condition showed that the tensile strength of the weld joint was over 32kN, which is considerably higher than the required strength, i.e., 23kN.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.18 no.4
• /
• pp.174-178
• /
• 2008

Nano-crystalline slaked lime was synthesized using design of experiment. In order to synthesize slaked lime, calcium chloride $(CaCl_2)$ and urea were used as starting materials. Calcium chloride solution and urea solution were mixed and heated in vessel that calcium carbonate was precipitated during heating. Precipitates were filtered, washed several times using D.I.water and ethanol and finally dried in oven. Slaked lime $(Ca(OH)_2)$ has been fabricated by the hydration of calcined $CaCO_3$. Design of experiment (Taguchi method) was used to optimize parameter, to minimize noise factors of experiment and to statistically analyze the results. Slaked lime having about 50 nm in optimized crystallite size could be obtained by calcination of $CaCO_3$ at $1000^{\circ}C$ for 0.5 h and hydration with D.I water containing ethanol and oxalic acid.