Improved Measurement of the Kinetics of Crystallization in a Batch Experiment

1993 ◽  
Vol 58 (8) ◽  
pp. 1839-1847 ◽  
Author(s):  
Jaroslav Nývlt ◽  
Miloslav Karel
Keyword(s):  
Experimental Data ◽  
Crystal Size ◽  
Evaluation Method ◽  
Potassium Sulfate ◽  
Batch Experiment ◽  
Improved Method ◽  
Short Intervals ◽  
Wide Range ◽  
Kinetics Of ◽  
Single Batch

An improved method is described whereby knowledge of the supersaturation course during a run and measurement of the final product crystal size distribution yield the growth rate of crystals and the nucleation rate in a wide range of supersaturations from only a single batch experiment. The evaluation method is refined by the interpolation of experimental data for short intervals of time. The method is illustrated using potassium sulfate crystallization as an example.

Kinetics of the Crystallization of Potassium Sulfate

1993 ◽  
Vol 58 (8) ◽  
pp. 1848-1854 ◽  
Author(s):  
Miroslav Karel ◽  
Jaroslav Nývlt
Keyword(s):  
Experimental Data ◽  
Crystal Growth ◽  
Growth Rates ◽  
Potassium Sulfate ◽  
Kinetics Of

The kinetics of the crystallization of potassium sulfate has been determined using the MSMPR technique. Values of the nucleation and crystal growth rates evaluated from the experimental data are compared with the corresponding literature data.

A general mechanism for the high-temperature pyrolysis of alkanes. The pyrolysis of isobutane

1974 ◽  
Vol 337 (1609) ◽  
pp. 199-216 ◽  
Keyword(s):  
Experimental Data ◽  
Computer Modelling ◽  
Single Pulse ◽  
General Mechanism ◽  
Methyl Radical ◽  
Hydrogen Atoms ◽  
Wide Range ◽  
Independent Experimental Data ◽  
Theoretical Considerations ◽  
Kinetics Of

A general mechanism is proposed to predict the kinetics of pyrolysis of alkanes at high temperatures (> 1000 K), based on theoretical considerations and on existing literature data. An experimental investigation of the pyrolysis of isobutane in a single-pulse shock tube over the temperature range 1200–1500 K is reported and the results are used to test the proposed mechanism. Computer modelling demonstrates that the mechanism is adequate to explain the experimental data provided that the following are included: ‘forbidden' isomerization reactions, non-Arrhenius rate constants for the methyl radical abstraction reactions, and the addition of hydrogen atoms to olefins. Although further refinement of the mechanism is to be expected as more data becomes available, it already enables pyrolytic behaviour to be predicted for a wide range of alkanes. The investigation also demonstrates how computer modelling can provide insight into a reaction mechanism even when the number of unknowns exceeds the independent experimental data available.

Calculation of the kinetics of crystallization based on a single batch experiment

1989 ◽  
Vol 54 (12) ◽  
pp. 3187-3197 ◽  
Author(s):  
Jaroslav Nývlt
Keyword(s):  
Crystal Growth ◽  
Size Distribution ◽  
Kinetic Data ◽  
Growth Kinetic ◽  
Crystal Size ◽  
Batch Crystallization ◽  
Crystallization Experiment ◽  
Kinetics Of ◽  
Single Batch ◽  
Kinetics Of Crystal Growth

The kinetics of crystal growth and nucleation in dependence on the supersaturation of a solution of KCL were evaluated based on a single batch crystallization experiment, where the supersaturation was monitored refractometrically and the product crystal size distribution was established at the end of the experiment. The crystal growth kinetic data obtained compare well with published values, for the nucleation data the agreement is less satisfactory.

An expression for droplet evaporation incorporating thermal effects

2011 ◽  
Vol 667 ◽  
pp. 260-271 ◽  
Author(s):  
K. SEFIANE ◽  
R. BENNACER
Keyword(s):  
Experimental Data ◽  
Thermal Effects ◽  
Droplet Evaporation ◽  
Theoretical Expression ◽  
Dimensionless Number ◽  
Wide Range ◽  
Isothermal Diffusion ◽  
Rate Of Evaporation ◽  
First Time ◽  
Kinetics Of

We propose a general theoretical expression for sessile droplets' evaporation, incorporating thermal effects related to the thermal resistance of the substrate and liquid properties. We develop an expression which accounts for thermal effects associated with evaporative cooling; the latter leads to a reduction in the rate of evaporation, which is not accounted for in the current theories, i.e. ‘isothermal diffusion theories’. The threshold for transition to a regime in which thermal effects start to be significant is identified through a dimensionless number which includes substrate and liquid properties as well as the kinetics of evaporation. The proposed theory is validated against experimental data in a very wide range of conditions and for a variety of systems. The developed expression extends the domain of use of diffusion-based models for droplet evaporation and accurately describes some aspects of the phenomenon which, to the best of our knowledge, are highlighted for the first time.

scholarly journals Challenges in estimating the motility parametersn of single processive motor proteins

2017 ◽  
Author(s):  
F. Ruhnow ◽  
L. Kloß ◽  
S. Diez
Keyword(s):  
Experimental Data ◽  
Single Molecule ◽  
Motor Proteins ◽  
Evaluation Method ◽  
Length Distribution ◽  
Acquisition Time ◽  
Filament Length ◽  
Experimental Conditions ◽  
Run Length ◽  
Wide Range

AbstractCytoskeletal motor proteins are essential to the function of a wide range of intracellular mechanosystems. The biophysical characterization of their movement along their filamentous tracks is therefore of large importance. Towards this end, single-molecule, in vitro stepping-motility assays are commonly used to determine motor velocity and run length. However, comparing results from such experiments has proved difficult due to influences from variations in the experimental conditions and the data analysis methods. Here, we investigate the movement of fluorescently-labeled, processive, dimeric motor proteins and propose a unified algorithm to correct the measurements for finite filament length as well as photobleaching. Particular emphasis is put on estimating the statistical errors associated with the proposed evaluation method as knowledge of these values is crucial when comparing measurements from different experiments. Testing our approach with simulated and experimental data from GFP-labeled kinesin-1 motors stepping along immobilized microtubules, we show (i) that velocity distributions should be fitted by a t location-scale probability density function rather than by a norm*al distribution, (ii) that the impossibility to measure events shorter than the image acquisition time needs to be accounted for, (iii) that the interaction time and run length of the motors can be estimated independent of the filament length distribution, and (iv) that the dimeric nature of the motors needs to be considered when correcting for photobleaching. Moreover, our analysis reveals that controlling the temperature during the experiments with a precision below 1 K is of importance. We believe, our method will not only improve the evaluation of experimental data, but will also allow for better statistical comparisons between different populations of motor proteins (e.g. with distinct mutations or linked to different cargos) and filaments (e.g. in distinct nucleotide states or with different posttranslational modifications).

Kinetics of the Luminescence of Isoelectronic Rare-Earth Ions In III-V Semiconductors

1993 ◽  
Vol 301 ◽  
Author(s):  
H.J. Lozykowski
Keyword(s):  
Experimental Data ◽  
Energy Transfer ◽  
Rare Earth ◽  
Excited States ◽  
Quantitative Agreement ◽  
Host Lattice ◽  
Rare Earth Ions ◽  
Wide Range ◽  
Decay Times ◽  
Kinetics Of

ABSTRACTIn this work we have developed a model for the kinetics of the energy transfer from the host lattice to the localized core excited states of rare earth isoelectronic structured traps (REI-trap). We have derive a set of differential equations for semi-insulating semiconductor governing the kinetics of rare earth luminescence. The numerically simulated rise and decay times of luminescence show a good quantitative agreement with the experimental data obtained for InP:Yb, over a wide range of generation rates.

Chemisorption of hydrogen on nickel–magnesia catalysts. Part I. General kinetic characteristics

1969 ◽  
Vol 47 (16) ◽  
pp. 2933-2941 ◽  
Author(s):  
N. S. Viswanathan ◽  
L. M. Yeddanapalli
Keyword(s):  
Experimental Data ◽  
Nickel Catalysts ◽  
Activation Energies ◽  
Effect Of Temperature ◽  
Hydrogen Chemisorption ◽  
Kinetic Characteristics ◽  
Wide Range ◽  
Elovich Equation ◽  
Kinetics Of

A detailed study of the kinetics of hydrogen chemisorption on 3 different nickel catalysts, supported on magnesia and prepared by coprecipitation, has been made over a wide range of pressures and temperatures. The results have been analyzed in the light of the Elovich equation. Experimental data obtained by variations of pressure and temperature indicate the existence of a number of stages in the chemisorption process and support the multiple kinetic stage hypothesis suggested by Low. The effect of temperature on the parameters has been studied, and relations obtained which have been used to calculate activation energies for each of the stages.

Autowave Features of Plastic Deformation by Ductile Fracture

2013 ◽  
Vol 592-593 ◽  
pp. 664-667
Author(s):  
Dina Orlova ◽  
Vladimir Danilov ◽  
Lev B. Zuev
Keyword(s):  
Experimental Data ◽  
Plastic Deformation ◽  
Dissipative Structure ◽  
Vector Fields ◽  
Displacement Vector ◽  
Speckle Photography ◽  
Metallic Materials ◽  
Deformation Localization ◽  
Wide Range ◽  
Kinetics Of

The kinetics of fracture was examined for a wide range of metallic materials. Using speckle photography technique, displacement vector fields were recorded for the deforming sample. The deformation localization is an autowave process, which manifests macroscopic inhomogeneities from yield point to necking. This involves a changeover in the autowave types: phase autowave stationary dissipative structure propagating autowave collapse of autowave. The loading curves obtained for all studied materials have a similar autowave pattern emerging at the pre-fracture stage, no matter what is crystalline or microstructural state of material. Using experimental data on the kinetics of autowave collapse, the space-time coordinates of failure can be predicted for the object under load long before symptoms of fracture are detected visually.

Investigation of irradiation-induced nucleation processes in silicon and germanium

1995 ◽  
Vol 53 ◽  
pp. 224-225
Author(s):  
Harry A. Atwater ◽  
C.M. Yang ◽  
K.V. Shcheglov
Keyword(s):  
Room Temperature ◽  
Crystal Size ◽  
Initial Distribution ◽  
Engineering Control ◽  
Size Evolution ◽  
Silicon And Germanium ◽  
Ge Quantum Dot ◽  
And Control ◽  
Germanium Quantum Dots ◽  
Kinetics Of

Studies of the initial stages of nucleation of silicon and germanium have yielded insights that point the way to achievement of engineering control over crystal size evolution at the nanometer scale. In addition to their importance in understanding fundamental issues in nucleation, these studies are relevant to efforts to (i) control the size distributions of silicon and germanium “quantum dots𠇍, which will in turn enable control of the optical properties of these materials, (ii) and control the kinetics of crystallization of amorphous silicon and germanium films on amorphous insulating substrates so as to, e.g., produce crystalline grains of essentially arbitrary size.Ge quantum dot nanocrystals with average sizes between 2 nm and 9 nm were formed by room temperature ion implantation into SiO2, followed by precipitation during thermal anneals at temperatures between 30°C and 1200°C[1]. Surprisingly, it was found that Ge nanocrystal nucleation occurs at room temperature as shown in Fig. 1, and that subsequent microstructural evolution occurred via coarsening of the initial distribution.

A fuzzy neural network approach for modeling the growth kinetics of FeB and Fe2B layers during the boronizing process

2018 ◽  
Vol 106 (6) ◽  
pp. 603 ◽  
Author(s):  
Bendaoud Mebarek ◽  
Mourad Keddam
Keyword(s):  
Neural Network ◽  
Experimental Data ◽  
Fuzzy Neural Network ◽  
Treatment Time ◽  
Calculation Model ◽  
Average Error ◽  
Network Approach ◽  
Neural Network Approach ◽  
Fuzzy Neural ◽  
Kinetics Of

In this paper, we develop a boronizing process simulation model based on fuzzy neural network (FNN) approach for estimating the thickness of the FeB and Fe2B layers. The model represents a synthesis of two artificial intelligence techniques; the fuzzy logic and the neural network. Characteristics of the fuzzy neural network approach for the modelling of boronizing process are presented in this study. In order to validate the results of our calculation model, we have used the learning base of experimental data of the powder-pack boronizing of Fe-15Cr alloy in the temperature range from 800 to 1050 °C and for a treatment time ranging from 0.5 to 12 h. The obtained results show that it is possible to estimate the influence of different process parameters. Comparing the results obtained by the artificial neural network to experimental data, the average error generated from the fuzzy neural network was 3% for the FeB layer and 3.5% for the Fe2B layer. The results obtained from the fuzzy neural network approach are in agreement with the experimental data. Finally, the utilization of fuzzy neural network approach is well adapted for the boronizing kinetics of Fe-15Cr alloy.

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