DETERMINATION OF TRAPPING CENTER PARAMETERS OF Tl2Ga2S3Se LAYERED CRYSTALS BY THERMALLY STIMULATED CURRENT MEASUREMENTS

2010 ◽  
Vol 24 (14) ◽  
pp. 2149-2161 ◽  
Author(s):  
T. YILDIRIM ◽  
H. A. NASSER ◽  
N. M. GASANLY
Keyword(s):  
Cross Section ◽  
Trapping Center ◽  
Heating Rates ◽  
Thermally Stimulated Current ◽  
A Value ◽  
Initial Rise ◽  
Layered Crystals ◽  
Light Excitation ◽  
Good Agreement

We have carried out thermally stimulated current (TSC) measurements on as-grown Tl 2 Ga 2 S 3 Se layered single crystals in the temperature range 10–60 K with different heating rates of 0.6–1.5 K s1. The data were analyzed by curve fitting, initial rise, and peak shape methods. The results were in good agreement with each other. Experimental evidence was obtained for trapping center in Tl 2 Ga 2 S 3 Se crystal with activation energy of 11 meV. The capture cross section and concentration of the traps were found to be 1.5 × 10-23 cm 2 and 1.44 × 1010 cm -3, respectively. Analysis of the TSC data at different light excitation temperatures leads to a value of 18meV/decade for the traps distribution.

Device Modeling of a-Si:H Alloy Solar Cells: Calibration Procedure for Determination of Model Input Parameters

1998 ◽  
Vol 507 ◽  
Author(s):  
M. Zeman ◽  
R.A.C.M.M. Van Swaaij ◽  
E. Schroten ◽  
L.L.A. Vosteen ◽  
J.W. Metselaar
Keyword(s):  
Solar Cell ◽  
Material Properties ◽  
Calibration Procedure ◽  
Model Parameters ◽  
Model Input ◽  
A Value ◽  
Input Parameters ◽  
Simulated Material ◽  
Good Agreement

ABSTRACTA calibration procedure for determining the model input parameters of standard a-Si:H layers, which comprise a single junction a-Si:H solar cell, is presented. The calibration procedure consists of: i) deposition of the separate layers, ii) measurement of the material properties, iii) fitting the model parameters to match the measured properties, iv) simulation of test devices and comparison with experimental results. The inverse modeling procedure was used to extract values of the most influential model parameters by fitting the simulated material properties to the measured ones. In case of doped layers the extracted values of the characteristic energies of exponentially decaying tail states are much higher than the values reported in literature. Using the extracted values of model parameters a good agreement between the measured and calculated characteristics of a reference solar cell was reached. The presented procedure could not solve directly an important issue concerning a value of the mobility gap in a-Si:H alloys.

Measurement of the Isothermal Volume Dilation Accompanying the Unilateral Extension of Rubber

1959 ◽  
Vol 32 (2) ◽  
pp. 428-433
Author(s):  
Fred G. Hewitt ◽  
Robert L. Anthony
Keyword(s):  
Molecular Weight ◽  
Young’S Modulus ◽  
Experimental Results ◽  
Molecular Weights ◽  
Rubber Specimen ◽  
A Value ◽  
Fractional Increase ◽  
Internal Agreement ◽  
Good Agreement

Abstract The fractional increase in volume accompanying the isothermal extension of soft gum rubber was measured for four rubber samples at mean extensions of 14, 33, and 51%. The chain molecular weights Mc of the four samples were 5500, 5100, 4400, and 3000, with an estimated uncertainty of about 10% in each value of Mc. The observed fractional increase in volume ranged from 3.2×10−5 to 142×10−5, the latter value being observed for the sample of lowest chain molecular weight and at the extension of 51%. The experimental results for each sample have been represented by theoretical curves based on Gee's expression for the fractional increase in volume as a function of the sample extension. The theoretical curves exhibit good agreement with those of Gee, Stern, and Treloar. The process of fitting the theoretical curves to the experimental points constituted a determination of Young's modulus E for each rubber specimen. As a check on the experimental results, and also on the theory employed, determinations of E were also made by two additional methods, namely, from rough stess-strain curves, and from the relation E=3γρRT/Mc. With one exception, the internal agreement between the three determinations of E for the four different samples was satisfactory. The exception noted can probably be ascribed to the use of too small a value of Mc for the sample of lowest chain molecular weight.

Determination of Forces in a Magnetic Bearing Actuator: Numerical Computation With Comparison to Experiment

1992 ◽  
Vol 114 (4) ◽  
pp. 796-801 ◽  
Author(s):  
J. D. Knight ◽  
Z. Xia ◽  
E. McCaul ◽  
H. Hacker
Keyword(s):  
Relative Permeability ◽  
Free Space ◽  
Flux Distribution ◽  
Magnetic Bearing ◽  
Two Dimensional ◽  
Metal Parts ◽  
A Value ◽  
Axis Of Symmetry ◽  
Good Agreement

Calculations of the forces exerted on a journal by a magnetic bearing actuator are presented, along with comparisons to experimentally measured forces. The calculations are based on two-dimensional solutions for the flux distribution in the metal parts and free space, using finite but constant permeability in the metals. Above a relative permeability of 104 the effects of changes in permeability are negligible, but below 104 decreases in permeability cause significant decreases in the force. The calculated forces are shown to depend on the metal permeability more strongly when the journal is displaced from its centered position. The predicted forces in the principal attractive direction are in good agreement with experiment when a relatively low value of permeability is chosen. The forces measured normal to the axis of symmetry when the journal is displaced from that axis, however, are significantly higher than predicted by theory, even with a value of relative permeability larger than 5000. These results indicate a need for futher work including nonlinear permeability distributions.

scholarly journals Determination of Kinetic Parameters for the Thermal Decomposition of Parthenium hysterophorus

2018 ◽  
Vol 22 (1) ◽  
pp. 5-21 ◽  
Author(s):  
Alok Dhaundiyal ◽  
Suraj B. Singh ◽  
Muammel M. Hanon ◽  
Rekha Rawat
Keyword(s):  
Thermal Decomposition ◽  
Kinetic Parameters ◽  
Model Fitting ◽  
Frequency Factor ◽  
Heating Rates ◽  
Model Free ◽  
Higher Temperature ◽  
Good Agreement ◽  
Maximum Weight Loss

Abstract A kinetic study of pyrolysis process of Parthenium hysterophorous is carried out by using thermogravimetric analysis (TGA) equipment. The present study investigates the thermal degradation and determination of the kinetic parameters such as activation E and the frequency factor A using model-free methods given by Flynn Wall and Ozawa (FWO), Kissinger-Akahira-Sonuse (KAS) and Kissinger, and model-fitting (Coats Redfern). The results derived from thermal decomposition process demarcate decomposition of Parthenium hysterophorous among the three main stages, such as dehydration, active and passive pyrolysis. It is shown through DTG thermograms that the increase in the heating rate caused temperature peaks at maximum weight loss rate to shift towards higher temperature regime. The results are compared with Coats Redfern (Integral method) and experimental results have shown that values of kinetic parameters obtained from model-free methods are in good agreement. Whereas the results obtained through Coats Redfern model at different heating rates are not promising, however, the diffusion models provided the good fitting with the experimental data.

scholarly journals TO A QUESTION OF DETERMINATION OF HYDRAULIC RADIUS OF A BACKFILL FLOW FOR THE EXCENTRATIVE PLACEMENT OF PIPES IN DRILLING BORE

2018 ◽  
pp. 197-209
Author(s):  
V. M. Moishyshyn ◽  
Y. S. Biletskii ◽  
V. V. Vryukalo ◽  
M. V. Seniushkovych
Keyword(s):  
Cross Section ◽  
Dimensionless Parameter ◽  
Internal Surface ◽  
Outer Radius ◽  
Hydraulic Radius ◽  
Cross Sectional ◽  
Internal Radius ◽  
First Time ◽  
Good Agreement

The processes of displacement of drilling clay backfill flow from the intertubular space formed by internal surface of external and external surfaces of inner tubes are considered. In case of eccentric placement of pipes it is proposed in the form of a cross-section of the flow of a backfill to take the area limited from the outside by the Pascal's snail, and from the inside - the outer surface of the inner pipe at the first time. The formulas for determining areas of the cross section of the flow and the stagnant zone, the perimeter and the hydraulic radius of the section ofthe flow for the eccentric placement of the pipes in the bore are proposed. The dimensionless parameter α is introduced as the ratio of the centripetal distance to difference between internal radius of outer pipe and outer radius of inner tube. It was found that with increasing of α cross-sectional area and their hydraulic radii are increasing, and the area of stagnant zones decreases according to parabolic laws.It is established that with the growth of α velocity of the backfill flow decreases according to parabolic laws and their values are in good agreement with the experimental data.

scholarly journals Bestimmung von Streuquerschnitten für thermische Elektronen aus der Linienform von ECR-Signalen / Determination of the Scattering Cross Section for Thermal Electrons from the Line Shape of ECR-Signals

1974 ◽  
Vol 29 (2) ◽  
pp. 239-244 ◽  
Author(s):  
E. Schultes ◽  
R. Schumacher ◽  
R. N. Schindler
Keyword(s):  
Cross Section ◽  
Line Width ◽  
Microwave Power ◽  
Line Shape ◽  
Cyclotron Resonance ◽  
Drift Tube ◽  
Electron Cyclotron Resonance ◽  
Scattering Cross ◽  
Good Agreement

Changes of line width and line shape of electron cyclotron resonance (ecr) signals are measured as function of the pressure of neutral gases. The results are discussed in terms of an analysis for the absorption of microwave power by electrons given by Fehsenfeld et al. Good agreement is found for σ-values as obtained in ecr and drift tube measurements.

scholarly journals The Momentum Transfer Cross Section for Electrons in Helium Derived from Drift Velocities at 77°K

1970 ◽  
Vol 23 (5) ◽  
pp. 667 ◽  
Author(s):  
RW Crompton ◽  
MT Elford ◽  
AG Robertson
Keyword(s):  
Energy Range ◽  
Momentum Transfer ◽  
Cross Section ◽  
Scattering Length ◽  
Direct Determination ◽  
A Value ◽  
Energy Dependent ◽  
Momentum Transfer Cross Section

Drift velocities of electrons in helium at 76.8�K have been measured for 8 X lO−20 ≤ E/N ≤ 2 X lO−17 V cm2. From these data, and the earlier measurements of Crompton, Elford, and Jory made at 293�K, the energy-dependent momentum transfer cross section has been determined for electrons with energies between 0.008 and 6 eV. The present cross section agrees with that of Crompton, Elford, and Jory to within 1 %. The extension of the energy range to 8 meV permits a direct determination of the scattering length, for which a value of 1.19 ao is obtained.

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