Model of corrosion cracking of irradiated austenitic steels. Part 2. Determination of model parameters and its verification

2019 ◽  
pp. 178-190
Author(s):  
B. Z. Margolin ◽  
A. A. Sorokin ◽  
N. E. Pirogova ◽  
V. A. Potapova ◽  
Aki Toivonen ◽  
...  
Keyword(s):  
Experimental Data ◽  
Constitutive Equations ◽  
Corrosion Cracking ◽  
Neutron Dose ◽  
Austenitic Steels ◽  
Model Parameters ◽  
Original Experimental Data

Based on the analysis and generalization of reference and original experimental data unknown coefficients, parameters and functions in constitutive equations of the model developed in the first part of article have been defined. The model has been verified. The model allows one to predict the dependence σIASCCth (below which SCC does not occur at any time of tests) on neutron dose and to calculate the time of SCC initiation at stresses higher than σIASCCth.

VLE Determination of Carbon Dioxide Loaded Aqueous Alkanolamine Mixtures Using Modified Kent Eisenberg Model

2017 ◽  
Vol 231 (11-12) ◽  
Author(s):  
Humbul Suleman ◽  
Abdulhalim Shah Maulud ◽  
Zakaria Man
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Model Parameters ◽  
Thermodynamic Models ◽  
Carbon Dioxide Absorption ◽  
Proposed Model ◽  
Wide Range ◽  
Experimental Values ◽  
Good Agreement

AbstractA computationally simple thermodynamic framework has been presented to correlate the vapour-liquid equilibria of carbon dioxide absorption in five representative types of alkanolamine mixtures. The proposed model is an extension of modified Kent Eisenberg model for the carbon dioxide loaded aqueous alkanolamine mixtures. The model parameters are regressed on a large experimental data pool of carbon dioxide solubility in aqueous alkanolamine mixtures. The model is applicable to a wide range of temperature (298–393 K), pressure (0.1–6000 kPa) and alkanolamine concentration (0.3–5 M). The correlated results are compared to the experimental values and found to be in good agreement with the average deviations ranging between 6% and 20%. The model results are comparable to other thermodynamic models.

New parameters controlling the effect of temperature on enzyme activity

2007 ◽  
Vol 35 (6) ◽  
pp. 1543-1546 ◽  
Author(s):  
R.M. Daniel ◽  
M.J. Danson ◽  
R. Eisenthal ◽  
C.K. Lee ◽  
M.E. Peterson
Keyword(s):  
Experimental Data ◽  
Enzyme Activity ◽  
Thermal Behaviour ◽  
Equilibrium Model ◽  
Thermal Inactivation ◽  
Effect Of Temperature ◽  
Model Parameters ◽  
Effects Of Temperature ◽  
Activity Loss

Arising from careful measurements of the thermal behaviour of enzymes, a new model, the Equilibrium Model, has been developed to explain more fully the effects of temperature on enzymes. The model describes the effect of temperature on enzyme activity in terms of a rapidly reversible active–inactive (but not denatured) transition, revealing an additional and reversible mechanism for enzyme activity loss in addition to irreversible thermal inactivation at high temperatures. Two new thermal parameters, Teq and ΔHeq, describe the active–inactive transition, and enable a complete description of the effect of temperature on enzyme activity. We describe here the Model and its fit to experimental data, methods for the determination of the Equilibrium Model parameters, and the implications of the Model for the environmental adaptation and evolution of enzymes, and for biotechnology.

On the determination of single-crystal plasticity parameters by diffraction: optimization of a polycrystalline plasticity model using a genetic algorithm

2012 ◽  
Vol 45 (4) ◽  
pp. 627-643 ◽  
Author(s):  
T. Skippon ◽  
C. Mareau ◽  
M. R. Daymond
Keyword(s):  
Experimental Data ◽  
Genetic Algorithm ◽  
Model Parameters ◽  
Plasticity Model ◽  
Flow Curves ◽  
Lattice Strains ◽  
Tension And Compression ◽  
Single Crystal Plasticity ◽  
Selection Of

A genetic algorithm was implemented in order to optimize the selection of parameters within a polycrystalline plasticity model. Previously collected experimental data from tests performed on textured Zircaloy-2, consisting of macroscopic flow curves, lattice strains and Lankford coefficients, all measured in both tension and compression in three principle directions of a plate, were reproduced by the model. The results obtained were found to be comparable to prior attempts to optimize the model parameters manually.

scholarly journals Algorithm for determination of S-N curves of the structural elements subjected to cyclic loading

2018 ◽  
Vol 16 (1) ◽  
pp. 81-91 ◽  
Author(s):  
Nenad Stojkovic ◽  
Dragoslav Stojic ◽  
Srdjan Zivkovic ◽  
Gordana Toplicic-Curcic
Keyword(s):  
Experimental Data ◽  
Fatigue Life ◽  
Cyclic Loading ◽  
Fatigue Tests ◽  
Likelihood Method ◽  
Model Parameters ◽  
Structural Elements ◽  
Number Of Cycles ◽  
Predetermined Number

Fatigue life prediction of structural elements subjected to cyclic loading is usually performed using S-N curves, obtained from the experimental data from fatigue tests. However, in some cases the samples do not exhibit failure, due to reaching the predetermined number of cycles, failure of a non-relevant segment or terminating the test because of some other reason. These samples are usually referred to as runouts, and the data obtained from them could be used for determination of S-N curves as well. In this paper, the algorithm based on Maximum Likelihood method is proposed for the determination of S-N curves from experimental data that contain runouts. Following the algorithm, a MATLAB code was written and the verification was performed using the experimental data from the literature. The results showed that it could be successfully used for taking into account the runouts in the process of determination of S-N model parameters. It was concluded that the inclusion of runouts could significantly influence the predicted fatigue life, especially at the lower stress levels.

EXTRACTION OF ILLUMINATED SOLAR CELL AND SCHOTTKY DIODE PARAMETERS USING A GENETIC ALGORITHM

2005 ◽  
Vol 16 (07) ◽  
pp. 1043-1050 ◽  
Author(s):  
A. SELLAI ◽  
Z. OUENNOUGHI
Keyword(s):  
Experimental Data ◽  
Genetic Algorithm ◽  
Solar Cell ◽  
Schottky Diode ◽  
Initial Guess ◽  
Model Parameters ◽  
Model Calculations ◽  
Subsequent Determination ◽  
Critical Requirement

Details concerning the implementation of a versatile genetic algorithm are presented. Solar cell and Schottky diode model parameters are extracted based on the fitness of experimental data to theoretical curves simulated in the framework of certain physical processes and the use of this genetic algorithm. The method is shown to be a reliable alternative to conventional numerical techniques in fitting experimental data to model calculations and the subsequent determination of model related parameters. It is demonstrated, through two examples in particular, that some of the drawbacks associated with the conventional methods can be circumvented if a genetic algorithm is used instead. For instance, a good initial guess is not a critical requirement for convergence and an initial broad range for each of the fitting parameters is enough to achieve reasonably good fits.

Parameter Determination for Chloride and Tritium Transport in Undisturbed Lysimeters during Steady Flow

1992 ◽  
Vol 23 (2) ◽  
pp. 89-104 ◽  
Author(s):  
Ole H. Jacobsen ◽  
Feike J. Leij ◽  
Martinus Th. van Genuchten
Keyword(s):  
Experimental Data ◽  
Unsaturated Flow ◽  
Transport Model ◽  
Time Moment ◽  
Breakthrough Curves ◽  
Coarse Sand ◽  
Retardation Factor ◽  
Parameter Determination ◽  
Model Parameters ◽  
Water Fraction

Breakthrough curves of Cl and 3H2O were obtained during steady unsaturated flow in five lysimeters containing an undisturbed coarse sand (Orthic Haplohumod). The experimental data were analyzed in terms of the classical two-parameter convection-dispersion equation and a four-parameter two-region type physical nonequilibrium solute transport model. Model parameters were obtained by both curve fitting and time moment analysis. The four-parameter model provided a much better fit to the data for three soil columns, but performed only slightly better for the two remaining columns. The retardation factor for Cl was about 10 % less than for 3H2O, indicating some anion exclusion. For the four-parameter model the average immobile water fraction was 0.14 and the Peclet numbers of the mobile region varied between 50 and 200. Time moments analysis proved to be a useful tool for quantifying the break through curve (BTC) although the moments were found to be sensitive to experimental scattering in the measured data at larger times. Also, fitted parameters described the experimental data better than moment generated parameter values.

Equilibrium Sorptions in Heterogeneous Ion Exchange Membranes

1992 ◽  
Vol 57 (9) ◽  
pp. 1905-1914
Author(s):  
Miroslav Bleha ◽  
Věra Šumberová
Keyword(s):  
Experimental Data ◽  
Ion Exchange ◽  
Total Content ◽  
Distribution Coefficients ◽  
Exchange Capacity ◽  
Ion Exchange Membranes ◽  
Ion Exchange Capacity ◽  
Equilibrium Sorption ◽  
Inhomogeneity Factor

The equilibrium sorption of uni-univalent electrolytes (NaCl, KCl) in heterogeneous cation exchange membranes with various contents of the ion exchange component and in ion exchange membranes Ralex was investigated. Using experimental data which express the concentration dependence of equilibrium sorption, validity of the Donnan relation for the systems under investigation was tested and values of the Glueckauf inhomogeneity factor for Ralex membranes were determined. Determination of the equilibrium sorption allows the effect of the total content of internal water and of the ion-exchange capacity on the distribution coefficients of the electrolyte to be determined.

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