• Food Science and Biotechnology
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• 제16권2호
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• pp.255-259
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• 2007

The effects of temperature heating-up rate and pressure building-up phase on the inactivation of Listeria innocua ATCC 33090 were evaluated in buffered peptone water. The number of L. innocua was reduced by 5.57 and 6.52 log CFU/mL during the nonisothermal treatment (the come-up time followed by isothermal process) and the isothermal treatment, respectively, at $60^{\circ}C$. When compared to the isothermal treatment (0.76$33.2^{\circ}C/min$ of temperature heating-rate. The effect of the combined high pressure and thermal processing on the inactivation of L. innocua increased with increasing pressure and temperature. At all temperature levels from 40 to $60^{\circ}C$ under 700 MPa, L. innocua was not detected by enrichment culture (>7 log reduction).

• Bulletin of the Korean Chemical Society
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• 제31권7호
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• pp.1988-1992
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• 2010

4-Amino-1,2,4-triazole copper complex (4-ATzCu) was synthesized, and its thermal behaviors, nonisothermal decomposition reaction kinetics were studied by DSC and TG-DTG techniques. The thermal decomposition reaction kinetic equation was obtained as: $d\alpha$ / dt =$10^{22.01}$ (1-$\alpha$)[-ln(1-$\alpha$)]$^{1/3}$ exp($-2.75\times10^4$ /T). The standard mole specific heat capacity of the complex was determined and the standard molar heat capacity is 305.66 $J{\cdot}mol^{-1}{\cdot}K^{-1}$ at 298.15 K. The entropy of activation $({\Delta}S^{\neq})$, enthalpy of activation $({\Delta}H^{\neq})$, and Gibbs free energy of activation $({\Delta}G^{\neq})$ are calculated as 171.88 $J{\cdot}mol^{-1}{\cdot}K^{-1}$ 225.81 $kJ{\cdot}mol^{-1}$ and 141.18 $kJ{\cdot}mol^{-1}$, and the adiabatic time-to-explosion of the complex was obtained as 389.20 s.

• Elastomers and Composites
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• 제40권1호
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• pp.3-11
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• 2005

시차열분석계(DSC)를 이용하여 달린(pendant) 탄소카본길이가 8(C-8), 12(C-12), 16(C-16)인 3 가지 종류의 무수화물(ASA)과 두 가지 촉매를 이용한 에폭시 수지의 경화 동력학을 연구하였다. 비등온(Nonisothermal)과 등전환(Isoconversional)법을 사용하였다. 비등온법의 결과는 무수화물의 달린 카본길이에 따른 결과에는 큰 차이가 없었다. 그러나 등전환법에서는 촉매사용에 따라 개시반응의 활성화 에너지가 C-8, C-12, 그리고 C-16의 경우 각각 $61.7{\sim}57.7kJ/mol$, $63.0{\sim}57.3 kJ/mol$, 그리고 $130.4{\sim}94.2 kJ/mol$이었다. 보고된 개시반응의 활성화에너지 20 kJ/mol 과 다른 것은 무수화물의 달린 탄소길이에 따른 효과로 해석된다.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1994년도 추계 학술발표회
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• pp.75-75
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• 1994

• Preventive Nutrition and Food Science
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• 제4권4호
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• pp.246-250
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• 1999

This study was conducted to develop the fermentation kinetic modeling for the prediction of pH and acidity changes in kimchi at isothermal and nonisothermal fermentation temperatures(0~15$^{\circ}C$) and salt concentrations(1.5~4.0%) using the traditional two-step method and alternative one-step method. The calculations of the two-step method of pH and acidity change during fermentation followed the pattern of the first order and zero order, respectively. The reaction rate constant of pH by the first order was increased from 0.008 {TEX}$day^{-1}${/TEX} to 0.017 {TEX}$day^{-1}${/TEX} by increasing the temperature from $0^{\circ}C$ to 15$^{\circ}C$ at 2.75% of salt concentration, and was decreased from 0.013 {TEX}$day^{-1}${/TEX} to 0.010 {TEX}$day^{-1}${/TEX} by increasing the salt concentration from 1.5% to 4.0% at 5$^{\circ}C$. For the pH and acidity of Kimchi, the zero order had a higher correlation than the first order to the estimate of the kinetics parameters by the one-step method. The {TEX}$E_{a}${/TEX} ranges of pH and acidity were 61.057~66.086 and 62.417~68.772 kJ/mole with different temperatures and salt concentrations. This one-step method had smaller and more realistic estimates of error(p〈0.05). The effective temperatures, {TEX}$T_{eff}${/TEX}, with 0~15$^{\circ}C$ of square function type of 12 hr intervals were 12.85, 11.48 and 12.46$^{\circ}C$ as increasing the salt concentration, 1.50, 2.75 and 4.00%, respectively. The {TEX}$T_{eff}${/TEX} were higher values than the mean temperature(7.5$^{\circ}C$).

• Environmental Engineering Research
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• 제11권5호
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• pp.250-256
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• 2006

The combustion kinetics of poly(ethylene terephthalate) (PET) was studied by the dynamic model which accounts for the thermal decomposition of polymer at any time. The kinetic analysis was performed by a conventional nonisothermal thermogravimetric (TG) technique at several heating rates between 10 and 40 K/min in air atmosphere. The thermal decomposition of PET in air atmosphere was found to be a complex process composed of at least two stages for which kinetic values can be calculated. The combustion kinetic analysis of PET gave apparent activation energy for the first stage of $257.3{\sim}269.9\;kJ/mol$, with a value of $140.5{\sim}213.8\;kJ/mol$ for the second stage. To verify the effectiveness of the kinetic analysis method used in this work, the kinetic analysis results were compared with those of various analytical methods. The kinetic parameters were also compared with values of the pyrolysis of PET in nitrogen atmosphere.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.589-594
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• 1993

This paper presents a fault detection strategy that discriminates the faulty sensor and that detects the component fault using a bank of observers for the system in which sensor fault and component fault can occur simultaneously. Observers as many as the number of measurements are designed, and each observer uses measurements excluding sequentially one measurement, to estimate the state variables. The faulty sensor can be found out by comparing each state variable from different observer. Next, component fault can be detected by using measurements from the sensors excluding the faulty sensor. The suggested strategy is applied to a nonisothermal, series reaction with unknown reaction kinetics in a CSTR. This strategy is found out to perform well even in the case that the sensor and component fault occur simultaneously. Since each observer is designed to be independent of reaction kinetics, this strategy is not affected by the model uncertainty and nonlinearity of the reaction kinetics.

• 한국세라믹학회지
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• 제24권5호
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• pp.417-422
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• 1987

Kinetic studies were made on the thermal decomposition of hydrated magnesium aluminum double sulfate by a nonisothermal TG method. Thermal analyses of the dehydration of tricosahydrate showed that the reaction proceeded via decahydrate to the anhydrous MgAl2(SO4)4 in the range 50$^{\circ}$to 400$^{\circ}C$. Decomposition of MgAl2(SO4)4 occurred as the two-step between 650$^{\circ}$ and 970$^{\circ}C$. Dehydration of MgAl2(SO4)4$.$23H2O and a 2D diffusion controlled with an activation energy of 16.6kcal/mole, respectively. MgAl2(SO4)4 fitted the contracting volume model with an activation energy of 10.5kcal/mole, and MgSO4 fitted a contracting area model with an activation of 4.5kcal/mole.

• Elastomers and Composites
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• 제22권4호
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• pp.333-339
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• 1987

A modern kinetic evaluation method for nonisothermal reactions measured with Differential Scanning Calorimetry(DSC) is presented. It is based on multiple linear regression analysis using a number of curve points in a selectable range of conversion. The obtained kinetic data are the basis to compute a reaction process under any condition e.g. isothermal or adiabatic. The DSC measurements was performed on a Mettler TA3000 SYSTEM with the built in evaluation software. Mainly the following reactions are discussed: vulcanization of natural rubber compounds containing vulcanizing accelerators. The purpose of this work is to analyse the vulcanization kinetics of typical NR vulcanization systems using DSC. These systems were chosen because they are typically reactive elastomer and are commercially important.

• 한국식품과학회지
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• 제25권6호
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• pp.643-648
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• 1993

표준온도 상당시간을 이용하여 규칙적인 온도변화 조건에서 식품의 품질변화를 간편하게 예측하는 근사식의 유효성을 밝히기 위하여, 비등온 가속조건 및 상온저장 조건에서 Sucrose 가수분해속도를 측정한 설험자료로 비교, 분석을 분석하였다. 정속가열 (定速加熱) 가속(加速)실험을 통해 구한 sucrose의 가수분해 반응은 1차 반응이고, 활성화에너지는 25.84kcal/mol이었으며, 반응속도상수는 pH가 감소함에 따라 직선적으로 증가하였다. 하루 동안의 온도변화를 sine wave 형태 온도변화로 가정하고 하루 동안에 일어난 품질변화를 표준온도 $T_{ref}$에서 몇일 동안에 일어난 변화에 상당하는가를 의미하는 표준온도 상당시간 $T_{eq.i}$를 이용하여 품질변화를 근사적으로 간단히 예측하는 방법을 제안하였다. Sucrose 액체 모델 시스템을 sine wave 형태의 규칙적인 온도변화 조건에서의 가속 가수분해실험 결과와 $T_{eq.i}$를 이용하여 품질변화를 computer simulation한 결과, 실험값과 예측값과의 상관계수는 0.99로서 잘 일치하였으므로 표준온도상당시간을 이용한 예측 모델의 유효함을 확인하였다. 뿐만 아니라 sucrose 모델 시스템을 실제 상온 저장한 실험결과와 계절적 온도변화를 computer simulation하여 예측한 값과는 상관계수가 0.92로서 잘 일치하였다.