scholarly journals The influence of stress and strain on the physical pro­perties of matter. Part II. Electrical conductivity ( continued ).The alteration of the electrical conductivity of cobalt, magnesium, steel, and platinum-iridium by longi­tudinal traction

1886 ◽  
Vol 39 (239-241) ◽  
pp. 503-531
Keyword(s):  
Electrical Conductivity ◽  
Electrical Resistance ◽  
Royal Society ◽  
Stress And Strain ◽  
Previous Communication

In a previous communication to the Royal Society,* I pointed out that whilst with iron the electrical resistance is temporarily increased by temporary longitudinal traction, that of nickel is decreased, pro­vided the stress be not carried beyond a certain limit, and this, too, in spite of the change of dimensions, namely, increase of length and diminution of diameter, which follow from the stress.

scholarly journals III. The influence of stress and strain on the physical properties of matter. Part II. electrical conductivity- continued . The alteration of the electrical conductivity of cobalt, magnesium, steel, and platinum-iridium produced by longitudinal traction; Discovery of simple relations between the ‘critical points’ of metals

1884 ◽  
Vol 37 (232-234) ◽  
pp. 386-391 ◽  
Keyword(s):  
Electrical Conductivity ◽  
Electrical Resistance ◽  
Unit Area ◽  
Specific Resistance ◽  
Stress And Strain ◽  
Moderate Amount ◽  
Iron Cobalt ◽  
Temporary Decrease ◽  
Permanent Increase ◽  
Cobalt And Nickel

The effect of temporary longitudinal traction on the electrical resistance of cobalt was determined by a method similar to that already described in a former portion of this memoir, and it was found that, like nickel, this metal has its resistance decreased by moderate temporary stress, in spite of the changes of dimensions which ensue. Whether the decrease of resistance would be changed to increase, as it is with nickel, by a greater amount of stress, has not yet been ascertained, but should this be the case, the magnitude of the stress per unit area which would suffice for the purpose must be much greater with cobalt than with nickel. As with nickel, permanent extension and rolling diminish the effect of temporary longitudinal traction, so that there is a larger decrease of resistance caused by a given stress with annealed than with unannealed cobalt. Cobalt is remarkable for the extreme persistence with which the same load, when applied again, and again, continues to produce per­ manent increase of resistance, and probably increase of length, but for a moderate amount of permanent extension the increase of resistance is more than accounted for by the permanent increase of length and diminution of section which take place; so that, as with iron and nickel, the specific resistance is decreased by moderate permanent extension. The permanent decrease of specific resistance per unit for unit permanent increase of length is, for iron, cobalt, and nickel, 0.02, 1.44, and 2.37 respectively; thus the permanent decrease of specific resistance, as well as the temporary decrease of resistance, is greater with nickel than with cobalt.

scholarly journals XX. The influence of stress and strain on the physical properties of matter

1886 ◽  
Vol 177 ◽  
pp. 801-837 ◽  
Keyword(s):  
Physical Properties ◽  
Electrical Resistance ◽  
Royal Society ◽  
Resistance To Change ◽  
Internal Resistance ◽  
Thermodynamic Theory ◽  
Stress And Strain ◽  
Elastic Solids ◽  
Dissipation Of Energy ◽  
Spare Time

I have already had the honour of presenting to the Royal Society an account of researches carried on with a view of determining the effects of stress and strain on the elasticity and electrical resistance of metals. Side by side with these researches were conducted others on magnetic induction and thermo-electricity, and a very considerable amount of experimental detail was collected with reference to the two last physical properties of matter. The results of the last mentioned investigations have, however, now remained unpublished for several years, for it seemed desirable that, previously to publication, certain phenomena should, if this were possible, have light thrown upon them by further experiments on elasticity. More especially was I anxious to examine into the causes of the loss of energy experienced by a wire when vibrating torsionally, for the interesting memoirs of G. Wiedemann † and D. E. Hughes led me to expect that my doing so would cause some insight to be gained regarding the above-mentioned phenomena. The results of these labours, which have now occupied almost the whole of my spare time for the last three years, I offer to the Society in the hope that they may prove as interesting to others as they are to myself. Researches of . Thomson and Wiedemann. Under the title of “The Elasticity and Viscosity of Metals,” Sir W. Thomson published a memoir, the first portion of which deals with the loss of energy of a wire when vibrating under the influence of torsional elasticity. It is pointed out ( a ) that, though no change of volume or shape can be produced without dissipation of energy, because of the accompanying change of temperature, estimates founded on the thermodynamic theory of elastic solids suffice to prove that the loss of energy due to this cause is small in comparison with the whole loss of energy which has been observed in many cases of vibration, ( b ) That, as a result of experiments in which a spring was vibrated alternately in air of ordinary pressure and in the exhausted receiver of an air-pump, there is an internal resistance to its motions immensely greater than the resistance of the air. Hence it is concluded that with solids as with liquids there exists an internal resistance to change of shape depending upon the rapidity of the change . The results of Thomson’s experiments are briefly as follows:—

scholarly journals Concerning emotive phenomena. —Part III. The influence of drugs upon the electrical conductivity of the palm of the hand

1919 ◽  
Vol 91 (635) ◽  
pp. 32-40 ◽  
Keyword(s):  
Electrical Conductivity ◽  
Healthy Subject ◽  
Electrical Resistance ◽  
Single Observation ◽  
Motor Theory ◽  
Few Data ◽  
Palm Of The Hand

I possess comparatively few data concerning the action of drugs upon “Emotivity” or, to put it more specifically, upon the electrical resistance of the palm of the hand. Except as regards atropine, with which I have made many observations to test the sudo-motor theory of the reaction, I find in my notes only one satisfactory observation upon each of the following drugs: alcohol, chloroform, morphia, which I will transcribe. Obviously, a single observation of any drug can give only a single facet of its action under the particular conditions of experiment. It will, however, be clear that the results have, in each instance, been such as might be anticipated on general principles with one notable exception, viz., atropine. Experiment 1: Alcohol . —A healthy subject, F. G., aged 30, with an initial hand conductance = 17 γ ( = 60, 000 ohms) gave emotive reactions = 37 γ to the threat of a burn (match struck) and 2 γ to an actual slight burn, immediately before and immediately after the ingestion of 50 c. c. of whisky. The conductance remained unaltered at 17 γ .

Semi-Electrical Conductivity of Gelcast Alumina Sintered under Nitrogen Atmosphere

2006 ◽  
Vol 11-12 ◽  
pp. 493-496 ◽  
Author(s):  
Ruben L. Menchavez ◽  
Koichiro Adachi ◽  
Masayoshi Fuji ◽  
Minoru Takahashi
Keyword(s):  
Electrical Conductivity ◽  
Electrical Resistance ◽  
Sintered Sample ◽  
Carbon Composite ◽  
Nitrogen Atmosphere ◽  
Potential Candidate ◽  
Nitrogen Gas ◽  
Conductive Property ◽  
Carbon Network

This work demonstrated an in-situ pyrolysis of gelcast alumina under reduction sintering to make alumina and carbon composite in providing semi-electrical conductivity. To increase the carbon content, the monomer was varied in the premix solution with reduction sintering in nitrogen gas. Two-probe method was used to measure electrical resistance of the sintered samples. The results revealed that the increase of monomer addition and sintering treatment were effective in reducing electrical resistance. The lowest value was 3.6×106-cm, which is a potential candidate for electrostatic shielding application. The reduction-sintered sample was re-sintered in an air in order to gain insight on the conductive path due to carbon network. Further tests such as XRD, TGA/DTA, and scanning electron microscopywere used to explain the semi-conductive property of the material.

scholarly journals A Method For Determination Of Specific Electrical Resistance Of Steel And Nano-Coating Sputtered On It

2015 ◽  
Vol 2 ◽  
pp. 118 ◽  
Author(s):  
Andris Martinovs ◽  
Josef Timmerberg ◽  
Konstantins Savkovs ◽  
Aleksandrs Urbahs ◽  
Paul Beckmann
Keyword(s):  
Electrical Conductivity ◽  
Magnetic Permeability ◽  
Electrical Resistance ◽  
Skin Effect ◽  
Specific Electrical Resistance ◽  
Specific Electrical Conductivity ◽  
Relative Magnetic Permeability ◽  
Nano Coating ◽  
Cylindrical Steel

The paper describes methods developed to determine specific electrical conductivity and relative magnetic permeability of cylindrical steel items and nano-coatings deposited on them by sputtering. Research enables development of a new method for determination of thickness of vacuum deposited nano- coating that is based on application of skin effect.

LOW TEMPERATURE RESISTIVITY OF TRANSITION ELEMENTS: VANADIUM, NIOBIUM, AND HAFNIUM

1957 ◽  
Vol 35 (8) ◽  
pp. 892-900 ◽  
Author(s):  
G. K. White ◽  
S. B. Woods
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Electrical Resistivity ◽  
Electrical Resistance ◽  
Thermal Resistivity ◽  
Superconducting Transition ◽  
Transition Elements ◽  
Pure Niobium ◽  
Temperature Resistivity ◽  
The Ideal

Measurements of the thermal conductivity from 2° to 90 ° K. and electrical conductivity from 2° to 300 ° K. are reported for vanadium, niobium, and hafnium. Although the vanadium and hafnium are not as pure as we might wish, measurements on these metals and on niobium allow a tabulation of the "ideal" electrical resistivity clue to thermal scattering for these elements from 300 ° K. down to about 20 ° K. Ice-point values of the "ideal" electrical resistivity are 18.3 μΩ-cm. for vanadium, 13.5 μΩ-cm. for niobium, and 29.4 μΩ-cm. for hafnium. Values for the "ideal" thermal resistivity of vanadium and niobium are deduced from the experimental results although for vanadium and more particularly for hafnium, higher purity specimens are required before a very reliable study of "ideal" thermal resistivity can be made. For the highly ductile pure niobium, the superconducting transition temperature, as determined from electrical resistance, appears to be close to 9.2 ° K.

scholarly journals III. On electrical conductivity and electrolysis in chemical compounds

1877 ◽  
Vol 25 (171-178) ◽  
pp. 322-327 ◽  
Keyword(s):  
Electrical Conductivity ◽  
Royal Society ◽  
Chemical Compounds ◽  
Considerable Time

In presenting this communication to the Royal Society I wish to state that it is only an abstract of a more extensive paper on the same subject which I hope to publish shortly, and which contains an account of experiments with nearly seventy substances, most of which were never used before for such an investigation. I tried also nearly all the liquefied gases, and a considerable time was spent in preparing them for this kind of research, that was often interrupted by fearful explosions. The invaluable opportunity which Mr. Warren De La Rue, F. R. S., granted me some time ago to try the same compounds with his very powerful battery, led to results which I hope the Society will not consider devoid of interest.

scholarly journals Synthesis of (Poly-methyl Methacrylate-lead Oxide) Nanocomposites and Studying their A.C Electrical Properties for Piezoelectric Applications

2018 ◽  
Vol 7 (4) ◽  
pp. 547-551
Author(s):  
Dalal Hassan ◽  
Ahmed Hashim
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Dielectric Loss ◽  
Methyl Methacrylate ◽  
Electrical Resistance ◽  
Lead Oxide ◽  
Piezoelectric Materials ◽  
Oxide Nanoparticles ◽  
Poly Methyl Methacrylate ◽  
Increase With Increase

Piezoelectric materials have been prepared from (poly-methyl methacrylate-lead oxide) nanocomposites for electronic applications. The lead oxide nanoparticles were added to poly-methyl methacrylate by different concentrations are (4, 8, and 12) wt%. The structural and dielectric properties of nanocomposites were studied. The results showed that the dielectric constant and dielectric loss of nanocomposites decrease with increase in frequency of applied electric field. The A.C electrical conductivity increases with increase in frequency. The dielectric constant, dielectric loss and A.C electrical conductivity of poly-methyl methacrylate increase with increase in lead oxide nanoparticles concentrations. The results of pressure sensor showed that the electrical resistance of (PMMA-PbO2) nanocomposites decreases with increase in pressure.

scholarly journals XIX. On the photographic arc spectrum of iron meteorites

1894 ◽  
Vol 185 ◽  
pp. 1023-1028
Keyword(s):  
Royal Society ◽  
Solar Spectrum ◽  
British Museum ◽  
Iron Meteorites ◽  
Electrolytic Iron ◽  
Comparison Spectrum ◽  
Size And Shape ◽  
Previous Communication ◽  
Oxyhydrogen Flame ◽  
Made In

In a communication to the Royal Society in 1887, I gave an account of certain experiments which I had made in connection with the spectra of various meteorites at various temperatures. The spectra were observed at the temperature of the oxyhydrogen flame and the electric spark without jar, and when glowed in vacuum tubes. Some larger specimens of the iron meteorites, Nejed and Obernkirchen, cut so that they were of a size and shape suitable for forming the poles of an arc lamp, having afterwards been kindly placed at my disposal by the Trustees of the British Museum, it became possible to study the arc spectra of these meteorites under very favourable conditions, all impurities introduced by the use of the carbon poles being thus avoided. The region of the spectrum photographed extends from K to D, in the case of each meteorite, and in addition to the solar spectrum, that of electrolytic iron, prepared by Professor Roberts-Austen, referred to in a previous communication, has been used as a comparison spectrum in one case.

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