Thermionic contrast between the mean work functions effective for thermal positive-ionic and electronic emissions from polycrystalline tungsten surfaces heated in vacuum: comparison between theory and experiment

2005 ◽  
Vol 249 (1-4) ◽  
pp. 238-245 ◽  
Author(s):  
Hiroyuki Kawano
Keyword(s):  
Polycrystalline Tungsten ◽  
The Mean ◽  
Work Functions ◽  
Theory And Experiment

scholarly journals Experimental Evaluation of Squeeze Film Supported Flexible Rotors

1982 ◽  
Author(s):  
M. D. Rabinowitz ◽  
E. J. Hahn
Keyword(s):  
Theoretical Model ◽  
Experimental Evaluation ◽  
Measurement Errors ◽  
Vibration Amplitude ◽  
Squeeze Film ◽  
Experimental Investigations ◽  
Flexible Rotors ◽  
The Mean ◽  
Lubricant Viscosity ◽  
Theory And Experiment

This paper describes the experimental investigations which were conducted to verify existing theoretical vibration amplitude predictions for centrally preloaded, squeeze film supported flexible rotors. The influence of measurement errors and operating condition uncertainties are quantified. The agreement between theory and experiment was excellent, and it is shown that any discrepancy can be explained in terms of errors in determining the mean lubricant viscosity and the orbit magnitudes. Hence, for the range of parameters investigated, the theoretical model and predictions therefrom are validated.

The structure of the shower front of large extensive air showers

1968 ◽  
Vol 46 (10) ◽  
pp. S9-S12 ◽  
Author(s):  
A. J. Baxter ◽  
A. A. Watson ◽  
J. G. Wilson
Keyword(s):  
Experimental Study ◽  
Measurement Errors ◽  
Time Distribution ◽  
Finite Size ◽  
Extensive Air Showers ◽  
Time Of Arrival ◽  
Air Showers ◽  
The Mean ◽  
Mean Time ◽  
Theory And Experiment

Using a method described previously (Baxter et al. 1966), an experimental study has been made of the time distribution of energy from the shower front of large extensive air showers detected by the Haverah Park 500-m array. Data are given on the mean time of arrival of energy in showers at axial distances over the range 250–950 m for all zenith angles, while average time distributions of the energy in the shower front are presented for some typical distance and zenith angle intervals. Experimental observations are compared with a theoretical prediction; a real discrepancy appears to exist between theory and experiment since about 25% more energy is observed in the 25 ns after the first detectable signal than is predicted. The result suggests a higher or more concentrated origin for muons than normally assumed.Assessment of measurement errors, particularly those arising from the sampling of a diffuse shower front by detectors of finite size, suggests that no intrinsic differences in the properties of the majority of air showers have yet been detected by this method.

Some work functions of vapour deposited uranium on polycrystalline tungsten foil

1967 ◽  
Vol 7 (3) ◽  
pp. 365-379 ◽  
Author(s):  
D.E. Barry ◽  
B.J. Hopkins ◽  
A.J. Sargood
Keyword(s):  
Polycrystalline Tungsten ◽  
Tungsten Foil ◽  
Work Functions

The conductivity of thin wires in a magnetic field

1950 ◽  
Vol 202 (1070) ◽  
pp. 378-394 ◽  
Keyword(s):  
Magnetic Field ◽  
Free Path ◽  
Bulk Material ◽  
Mean Free Path ◽  
Electron Theory ◽  
Conduction Electrons ◽  
Thin Wires ◽  
The Mean ◽  
The Magnetic Field ◽  
Theory And Experiment

A thin film or wire of metal has a lower electrical conductivity than the bulk material if the thickness is comparable with or smaller than the electronic mean free path. Previous workers have obtained expressions for the magnitude of the effect by integrating the Boltzmann equation and imposing the appropriate boundary conditions. The problem is re-examined from a kinetic theory standpoint, and it is shown that the same expressions are obtained by this method, usually rather more simply, while the physical picture is considerably clarified. The method is applied to an evaluation of the conductivity of a thin wire with a magnetic field along the axis, and it is found that the resistivity should decrease as the magnetic field is increased; it should be possible to derive the mean free path and velocity of the conduction electrons by comparison of theory and experiment. The theory has been confirmed by experimental measurements on sodium; estimates of electronic velocity and mean free path are obtained which are in fair agreement with the values given by the free-electron theory.

scholarly journals Self Diffusion in Liquid Metals

1975 ◽  
Vol 30 (5) ◽  
pp. 619-622
Author(s):  
R. V. Gopala Rao ◽  
A. K. Murthy
Keyword(s):  
Liquid Metals ◽  
Soft Part ◽  
Pair Potential ◽  
Spherical Model ◽  
Liquid Structure ◽  
Self Diffusion ◽  
Mean Spherical Model ◽  
The Mean ◽  
Square Well ◽  
Theory And Experiment

AbstractSelf-diffusion coefficients of liquid metals have been calculated according to the linear trajectory prescription. The soft part of the pair potential is being represented by a square well potential. The theoretical liquid structure factor, S(q), calculated under the mean spherical model (MSM) approximation, has been employed in the present calculations. The agreement between theory and experiment is encouraging and shows that the representation of the attractive forces by the square well potential is quite satisfactory for liquid metals.

scholarly journals A Thermochemical Computational Study on Hydroxyquinolines and their Azulene Analogues

2018 ◽  
Author(s):  
Moyassar Meshhal ◽  
Safinaz El-Demerdash ◽  
Ahmed El-Nahas
Keyword(s):  
Gas Phase ◽  
Computational Study ◽  
Enthalpies Of Formation ◽  
Mean Absolute Deviation ◽  
Electron Affinities ◽  
Absolute Deviation ◽  
The Mean ◽  
Experimental Values ◽  
Theory And Experiment ◽  
Good Agreement

Ab initio CBS-QB3 method has been used to determine gas-phase enthalpies of formation for 34 compounds including a number of hydroxyquinoline isomers, the corresponding azulene analogues and their parent systems. The mean absolute deviation of 4.43 kJ/mol reveals good agreement between our results and the available experimental data. Relative thermodynamic stabilities of hydroxyquinoline isomers and related analogues were discussed and several isomerization reactions enthalpies were derived. The same level of theory has also been utilized to calculate adiabatic ionization energies and electron affinities for the molecules with known experimental values and the agreement between theory and experiment was found to be within 8 kJ/mol.

A Thermochemical Computational Study on Hydroxyquinolines and their Azulene Analogues

2018 ◽  
Author(s):  
Moyassar Meshhal ◽  
Safinaz El-Demerdash ◽  
Ahmed El-Nahas
Keyword(s):  
Gas Phase ◽  
Computational Study ◽  
Enthalpies Of Formation ◽  
Mean Absolute Deviation ◽  
Electron Affinities ◽  
Absolute Deviation ◽  
The Mean ◽  
Experimental Values ◽  
Theory And Experiment ◽  
Good Agreement

Ab initio CBS-QB3 method has been used to determine gas-phase enthalpies of formation for 34 compounds including a number of hydroxyquinoline isomers, the corresponding azulene analogues and their parent systems. The mean absolute deviation of 4.43 kJ/mol reveals good agreement between our results and the available experimental data. Relative thermodynamic stabilities of hydroxyquinoline isomers and related analogues were discussed and several isomerization reactions enthalpies were derived. The same level of theory has also been utilized to calculate adiabatic ionization energies and electron affinities for the molecules with known experimental values and the agreement between theory and experiment was found to be within 8 kJ/mol.

Experimental Evaluation of Squeeze Film Supported Flexible Rotors

1983 ◽  
Vol 105 (3) ◽  
pp. 495-503 ◽  
Author(s):  
M. D. Rabinowitz ◽  
E. J. Hahn
Keyword(s):  
Theoretical Model ◽  
Experimental Evaluation ◽  
Measurement Errors ◽  
Vibration Amplitude ◽  
Squeeze Film ◽  
Experimental Investigations ◽  
Flexible Rotors ◽  
The Mean ◽  
Lubricant Viscosity ◽  
Theory And Experiment

This paper describes the experimental investigations which were conducted to verify existing theoretical vibration amplitude predictions for centrally preloaded, squeeze film supported flexible rotors. The influence of measurement errors and operating condition uncertainties are quantified. The agreement between theory and experiment was excellent, and it is shown that any discrepancy can be explained in terms of errors in determining the mean lubricant viscosity and the orbit magnitudes. Hence, for the range of parameters investigated, the theoretical model and predictions therefrom are validated.

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