Convection experiments with electrolytically heated fluid layers

1971 ◽  
Vol 48 (4) ◽  
pp. 703-719 ◽  
Author(s):  
E. W. Schwiderski ◽  
H. J. A. Schwab
Keyword(s):  
Time Dependence ◽  
Temperature Dependence ◽  
Electric Conductivity ◽  
Electric Current ◽  
Convection Flow ◽  
Convection Pattern ◽  
Fluid Layers ◽  
Direction Dependence ◽  
Heated Fluid ◽  
Theory And Experiments

Convection experiments described by Tritton & Zarraga (1967) with electrolytically heated fluid layers were renewed in order to investigate the reported phenomena, which were hitherto unknown and which contradicted a corresponding theory of Roberts. While the apparatus was essentially unchanged, provisions were incorporated to study the possible influence of several flow and equipment parameters on the convection pattern. With the exception of the temperature dependence of the electric conductivity, the new experiments displayed no essential effects of the convection parameters. Experiments with shallow fluid layers revealed a clear co-orientation of the convection flows with the electric current and a strong time dependence of the hexagonal patterns. Experiments with deeper fluid layers exhibited a considerably diminished time and direction dependence of the convection flow, and a significant reduction of the dilation of the cells. Based on these observations, it is concluded that no drastic differences between theory and experiments, and between internal and external heating, exist, provided the heating is sufficiently uniform.

Influence of carbon nano-tubes adding on electric conductivity and heating of elastomers under electric current flowing

2020 ◽  
pp. 67-78
Author(s):  
A. V. Shchegolkov ◽  
◽  
V. S. Yagubov ◽  
Yu. A. Khan ◽  
F. F. Komarov ◽  
...  
Keyword(s):  
Electric Conductivity ◽  
Electric Current ◽  
Carbon Nano Tubes

Electrical Conductivity of Chloro(phenyl)glyoxime and Its Co(II), Ni(II) and Cu(II) Complexes

2003 ◽  
Vol 68 (7) ◽  
pp. 1233-1242 ◽  
Author(s):  
Orhan Turkoglu ◽  
Mustafa Soylak ◽  
Ibrahim Belenli
Keyword(s):  
Electrical Conductivity ◽  
Temperature Dependence ◽  
Electric Conductivity ◽  
Crystal Structures ◽  
Elemental Analysis ◽  
Analysis Data ◽  
Elemental Analysis Data ◽  
The Stability ◽  
Xrd Patterns ◽  
Metal Ligand

Chloro(phenyl)glyoxime, a vicinal dioxime, and its Ni(II), Cu(II) and Co(II) complexes were prepared. XRD patterns of the complexes point to similar crystal structures. IR and elemental analysis data revealed the 1:2 metal-ligand ratio in the complexes. The Co(II) complex is a dihydrate. Temperature dependence of electrical conductivity of the solid ligand and its complexes was measured in the temperature range 25-250 °C; it ranged between 10-14-10-6 Ω-1 cm-1 and increased with rising temperature. The activation energies were between 0.61-0.80 eV. The Co(II) complex has lower electric conductivity than the Ni(II) and Cu(II) complexes. This difference in the conductivity has been attributed to differences in the stability of the complexes.

TEMPERATURE-DEPENDENCE OF PROTON CONDUCTIVITY IN HYDROGEN-BONDED MOLECULAR SYSTEMS

2007 ◽  
Vol 21 (19) ◽  
pp. 1239-1252 ◽  
Author(s):  
XIAO-FENG PANG ◽  
BO DENG ◽  
HUAI-WU ZHANG ◽  
YUAN-PING FENG
Keyword(s):  
Experimental Data ◽  
Electric Field ◽  
Temperature Dependence ◽  
Electric Conductivity ◽  
Proton Conductivity ◽  
Model System ◽  
Time Dependent ◽  
Molecular Systems ◽  
Damping Effect ◽  
Hydrogen Bonded

The temperature-dependence of proton electric conductivity in hydrogen-bonded molecular systems with damping effect was studied. The time-dependent velocity of proton and its mobility are determined from the Hamiltonian of a model system. The calculated mobility of (3.57–3.76) × 10-6 m 2/ Vs for uniform ice is in agreement with the experimental value of (1 - 10) × 10-2 m 2/ Vs . When the temperature and damping effects of the medium are considered, the mobility is found to depend on the temperature for various electric field values in the system, i.e. the mobility increases initially and reaches a maximum at about 191 K, but decreases subsequently to a minimum at approximately 241 K, and increases again in the range of 150–270 K. This behavior agrees with experimental data of ice.

scholarly journals Electric Currents Connected With the Proton Flares of 7 July and 2 September, 1966

1971 ◽  
Vol 43 ◽  
pp. 417-421
Author(s):  
A. B. Severny
Keyword(s):  
Active Region ◽  
Field Strength ◽  
Magnetic Flux ◽  
Electric Field ◽  
Electric Field Strength ◽  
Electric Conductivity ◽  
Electric Current ◽  
Current Density ◽  
High Energy ◽  
Electric Currents

It is observed that the change of the net magnetic flux associated with flares can exceed 1017 Mx/s, which corresponds according to Maxwell's equation to the e.m.f. ∼ 109 V which is specific for the high energy protons generated in flares. It is shown that this value of e.m.f. can hardly be compensated by e.m.f. of inductance which should appear due to the actually measured motions in a flare generating active region. The values of electric field strength thus found, together with measured values of electric current density (from rotH), leads to an electric conductivity which is 103 times smaller than usually adopted.

On the torque generated in a servo valve torque motor using permanent magnets

2007 ◽  
Vol 221 (5) ◽  
pp. 519-525 ◽  
Author(s):  
E Urata
Keyword(s):  
Permanent Magnet ◽  
Electric Current ◽  
Permanent Magnets ◽  
Fluid Power ◽  
Servo Valve ◽  
Leakage Flux ◽  
Theory And Experiments

This paper describes a theory and experiments for the conversion of electric current to mechanical torque by a torque motor in servo valves. The feature of the torque motor treated in this paper is the use of a permanent magnet. These kinds of torque motors are most commonly used in modern servo valves. For this type of torque motor, the theory developed by Merritt is most notable among fluid power engineers and scientists. However, his theory does not agree very well with experiments because he ignored the magnetic reluctance and leakage flux of permanent magnets. This paper corrects these points and offers some formulae that agree well with experiments.

Hysteresis of temperature dependence and scaling law in time dependence of sound velocity in sintered Bi2Sr2CaCu2O8+δ

1995 ◽  
Vol 241 (3-4) ◽  
pp. 336-344 ◽  
Author(s):  
Takeshi Fukami ◽  
Ryuji Kondo ◽  
Takashi Kobayashi ◽  
Kazue Kawatani ◽  
Fusao Ichikawa ◽  
...  
Keyword(s):  
Time Dependence ◽  
Temperature Dependence ◽  
Sound Velocity ◽  
Scaling Law

Effect of gases on the temperature dependence of the electric conductivity of CVD multiwalled carbon nanotubes

2007 ◽  
Vol 105 (1) ◽  
pp. 155-159 ◽  
Author(s):  
T. I. Buryakov ◽  
A. I. Romanenko ◽  
O. B. Anikeeva ◽  
V. L. Kuznetsov ◽  
A. N. Usol’tseva ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Temperature Dependence ◽  
Electric Conductivity ◽  
Multiwalled Carbon Nanotubes ◽  
Multiwalled Carbon ◽  
Effect Of Gases

Calculated Vs Measured Viscosities of Sol-Gel Processed Silica

1986 ◽  
Vol 73 ◽  
Author(s):  
T. A. Gallo ◽  
L. C. Klein
Keyword(s):  
Time Dependence ◽  
Temperature Dependence ◽  
Sol Gel ◽  
Linear Shrinkage ◽  
Beam Bending ◽  
Deflection Rate ◽  
Viscous Sintering

ABSTRACTThe densification of sol-gel processed silica was studied by comparing calculated and measured viscosities between 700 and 850°C. Linear shrinkage was measured in a dilatometer. From shrinkage data, relative bulk densities were determined. The densities were used in a model for viscous sintering to calculate viscosities. Beam-bending viscosimetry was used to determine viscosities directly. The deflection rate of a centrally loaded beam was measured. Both the calculated and measured viscosities had the same time dependence. The temperature dependence was also determined.

scholarly journals Studies on the temperature dependence of electric conductivity for metals in the Nineteenth Century: a neglected chapter in the history of superconductivity

2011 ◽  
Vol 33 (4) ◽  
pp. 4602-4302 ◽  
Author(s):  
Simón Reif-Acherman
Keyword(s):  
Nineteenth Century ◽  
Electrical Conductivity ◽  
Temperature Dependence ◽  
Electric Conductivity ◽  
Metals And Alloys ◽  
History Of ◽  
The Subject ◽  
Pure Metals

Two different lines of research had significant contributions to the discovery of superconductivity: the liquefaction of gases and the studies of the temperature dependence of the electrical conductivity, or resistance, of pure metals and alloys. Different publications have described and discussed the achievements in the first one of these subjects. The second subject had not received, however, the same attention. This article tries to fill this gap by presenting an account showing details of the evolution of the ideas, the first essentially experimental contributions to the subject and their corresponding responsible persons.

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