• 품질경영학회지
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• 제25권3호
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• pp.1-10
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• 1997

In the context of accelerated life tests, procedures are given for estimating the parameters in the modified Arrhenius model and for estimating mean life at a given future stress level. The conditional confidence intervals are obtained by conditioning on ancillary statistics and pivotal quantity. Using the data of Tobias and Trindada(1986), we illustrate conditional confidence interval for parameters under use condition in the modified Arrhenius model.

• 지질공학
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• 제24권4호
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• pp.575-581
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• 2014

The reliable measurement of geotechnical properties in cold regions should account for their fluctuations with temperature. The objective of this paper is to introduce a chemical model based on the Arrhenius equation that can predict the properties of materials as their temperature changes. The model can monitor phases and reaction rates as they change with temperature. It has been already applied in the fields of geology, construction, chemistry, materials engineering, and food science. The application of the Arrhenius equation requires a reliable estimate of the activation energy. Therefore, this study also demonstrates several methods for evaluating activation energy in different contexts through summaries and reviews of previous research related to the Arrhenius equation. This paper may be of wide use in obtaining temperature-dependent parameters in geotechnical engineering.

• 한국포장학회지
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• 제21권1호
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• pp.1-10
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• 2015

Enzyme kinetics-based respiration model can be effectively used for estimating respiration rate in $O_2$ consumption and $CO_2$ production of fresh produce as a function of $O_2$ and $CO_2$ concentrations. Arrhenius equation can be applied to describe the temperature dependence of the respiration rate. Parameters of enzyme kinetics-based respiration model and activation energy of Arrhenius equation were compiled from analysis of literature data and closed system experiment. They enable to estimate the respiration rate for any modified atmosphere conditions at temperature of interest and thus can be used for design of modified atmosphere packaging of fresh produce.

• 소성∙가공
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• 제26권1호
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• pp.18-27
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• 2017

A comparative study was performed on strain-compensated Arrhenius-type constitutive models established with two regression methods: polynomial regression and regression Kriging. For measurements at high temperatures, experimental data of 70Cr3Mo steel were adopted from previous research. An Arrhenius-type constitutive model necessitates strain compensation for material constants to account for strain effect. To associate the material constants with strain, we first evaluated them at a set of discrete strains, then capitalized on surrogate modeling to represent the material constants as a function of strain. As a result, disparate flow stress models were formed via the two different regression methods. The constructed constitutive models were examined systematically against measured flow stresses by validation methods. The predicted material constants were found to be quite accurate compared to the actual material constants. However, notable mismatches between measured and predicted flow stresses were revealed by the proposed validation techniques, which carry out validation with not the entire, but a single tensile test case.

• 대한기계학회논문집B
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• 제32권7호
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• pp.497-503
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• 2008

Hydrogen is considered as a fuel of the future for its renewability and environmental compatibility. The reforming of hydrocarbon fuels is currently the most important source of hydrogen, which is expected to continue for next several decades. In this study, extensive CFD simulations on the steam-methane reforming process were conducted to study the performance of four reaction models, i.e. three Arrhenius-type models and a user-defined function (UDF) model. The accuracies of different reaction models for various operating temperatures and steam carbon ratios (SCRs) were evaluated by comparing their CFD results with zero-dimensional intrinsic model of Xu and Froment. It was found that the UDF model generally produced more accurate results than Arrhenius-type models. However, it was also shown that Arrhenius-type models could be made sufficiently accurate by choosing appropriate reaction coefficients, and thus could also be useful for the simulation of the steam-methane reforming process.

• 전기화학회지
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• 제23권4호
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• pp.81-89
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• 2020

전기화학 소자의 성능을 이해하는 데 있어서 전해질 내 이온 전도 기작을 이해하는 것은 매우 중요하다. 그러나 이론적/실험적 어려움으로 인해 아직 완벽한 전해질 내 이온 전도 기작 분석법은 정립되지 못했다. 대신 이온 전도 기작을 기술하기 위한 몇 가지 수학적 모델이 고안되었으며, 본 총설에서는 대표적인 사례인 아레니우스(Arrhenius) 모델과 Vogel-Tammann-Fulcher(VTF) 모델을 소개한다. 일반적으로 이 두 모델은 이온 전도도, 확산 계수, 점도와 같은 이동 특성(transport properties)의 온도 의존성을 기술하는 데 사용되며, 주어진 전해질에 적합한 수학적 모델은 이동 물성의 로그 값과 온도의 역수가 이루는 그래프의 선형성을 통해 판별할 수 있다. 현재 많은 전해질 연구는 다양한 조성과 온도 범위에서 두 모델 중에서 더 적합한 모델을 선정하고, 이를 통해 이온 전도 기작 분석과 활성화 에너지를 도출한다. 향후 전해질 이동 특성을 더욱 정확하게 기술할 수 있는 모델의 개발이 필요하다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.1997-2002
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• 2007

The reformer is one of the most important chemical processes for the production of high purity hydrogen from fossil fuel. This study compares zero-dimensional model with CFD models for reaction analysis of methane-steam reformer. The zero-dimensional model is an empirical equation, however CFD model uses reactions of Arrhenius type. Because the reaction coefficients of the steam-methane catalytic reforming have not been reported before in the form of Arrhenius type, the present study aims to find the appropriate reaction coefficients. The used CFD code is Fluent 6.2 version. Several models are compared for the case of various operating temperature, mass of catalyst and steam to methane ratio.

• 전기학회논문지
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• 제57권2호
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• pp.208-213
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• 2008

In order to assess the reliability of the electronics control unit for vehicles, accelerated life test model and procedure are developed. By using this method, failure mechanism and life distribution are analyzed. The main results are as follows : i) the main failure mechanism is degradation failure that is, junction destruction of a semiconductor resin by high temperature. ii) the life distribution of the electronics control unit for vehicles is fitted well to Weibull life distribution and the accelerated life model of that is fitted well to Arrhenius model. iii) at the result of the life distribution, accelerated life test method is developed, and test time for life assessment will be shortened by 5,000 hours by this test method.

• 한국신뢰성학회지:신뢰성응용연구
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• 제13권1호
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• pp.65-76
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• 2013

In order to assess the reliability of engine mount for a vehicles, life test model and procedure are developed. By using this method, failure mechanism and life distribution are analyzed. The main results are as follows; i) the main failure mechanism is degradation failure of engine mount rubber by fatigue failure at dynamic load. ii) temperature is a second factor to affect a failure. iii) the life distribution of engine mount module is fitted well to Weibull life distribution and the shape parameter is 18.4 and the accelerated life model of that is fitted well to Arrhenius model.

• 전기학회논문지
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• 제68권1호
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• pp.52-60
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• 2019

In this paper, four types of insulation coils were fabricated by adding various kinds of glycols to improve the flexibility and adhesion of insulating coils in varnish dispersed with PAI / Nano Silica_15wt%. The applied voltage and frequency were 1.5 kV / 20 kHz for accelerated life evaluation. Through the 6th temperature stress level, the cause of the insulation breakdown of the coil was ignored and only the breakdown time was measured. The Arrhenius model was chosen based on the theoretical relationship between chemical reaction rate and temperature for estimating the insulation life of the coil due to accelerated thermal stress. Three types of distributions (Weibull, Lognormal, Exponential) were selected as the relationship between thermal stress model and distribution. The average insulation lifetime was estimated under the temperature stress of four types of insulation coils through the relationship between one kind of model and three kinds of distributions.