T.-C. MENDENHALL. — On the electrical résistance of soft carbon under pressure (Influence de la pression sur la résistance électrique du charbon doux); Philosophical Magazine, 5e série, t. XXII, p. 358; 1886. H. TOMLINSON. — Note on the effect of stress and strain on the electrical résistance of carbon (Note relative à l'influence de la pression sur la résistance électrique du charbon); Ibid., p. 442

1887 ◽  
Vol 6 (1) ◽  
pp. 249-250
Author(s):  
H. Crevaux
Keyword(s):  
Electrical Resistance ◽  
Stress And Strain ◽  
Philosophical Magazine ◽  
Soft Carbon

Stress State Evaluation in Complete Denture by Electrical Resistance Strain Gage

2014 ◽  
Vol 601 ◽  
pp. 171-176
Author(s):  
Anghel Cernescu ◽  
Nicolae Faur ◽  
Cristina Bortun
Keyword(s):  
Stress Distribution ◽  
Fracture Strength ◽  
Electrical Resistance ◽  
Strain State ◽  
Acrylic Resin ◽  
Stress And Strain ◽  
Complete Dentures ◽  
Strain Gages ◽  
Resistance Strain Gage ◽  
Acrylic Resins

Total dentures are made of acrylic resins and artificial teeth. Among the prevalent fracture types of the dentures, 29% was a mid-line fracture, in which 68% were observed in maxillary complete dentures and 28% in mandibular complete dentures. Due to the large number of failures recorded on the maxillary dentures, several studies were conducted to establish the causes that produce these failures but also to find solutions for their prevention. One source of information about the strength of a maxillary denture under the applied load, is represented by the establishment of the stress and strain state during the loading. Different methods have been used for investigating the strain or stress distribution during deformation of dentures. The purpose of this paper is to evaluate the stress and strain state of a maxillary denture loaded in compression until the final fracture. For this study, electrical resistance strain gage were used for evaluation the strain and stress distribution in the maxillary denture made of different acrylic resins. Based on observations from practice, the strain gages were applied on the middle line of the denture at the base of the incisors and respectively on the sides of the denture, under molars. The dentures were loaded until failure and were registered the strains in the located strain gages. Also, for each type of acrylic resin were determined separately the mechanical properties of elasticity and strength. Based on the tests conducted were determined the critical stress and strain in the areas of interest. In all the tests carried out the fracture occurred in the median area of the denture and the crack was initiated between the incisor teeth. The stress and strain field associated with the crack initiation mode showed a strong influence of geometry on the fracture strength of denture. Also the type of acrylic resin has a significant effect on the fracture strength of complete denture either by strength capacity but especially by their ability to elasticity. Based on this analysis have been established new criteria for selection of acrylic resins, not only for aesthetic reasons but also for elasticity and strength reasons.

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 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 On the variation of the electrical resistance of glass with temperature, density, and chemical composition

1883 ◽  
Vol 34 (220-223) ◽  
pp. 199-208 ◽  
Keyword(s):  
High Temperature ◽  
Chemical Composition ◽  
Electrical Resistance ◽  
Specific Resistance ◽  
Imperial College ◽  
Philosophical Magazine ◽  
Permanent Change ◽  
Physical Laboratory ◽  
Series Of Experiments ◽  
College Of Engineering

The following paper is a description of the methods adopted, and of the results obtained, in a series of experiments on the specific resistance of glass. These experiments were performed in the Physical Laboratory of the Imperial College of Engineering, Tokio, Japan. An account of some preliminary experiments on this subject was communicated by the author of this paper to the “Philosophical Magazine” for October, 1880. In that paper attention was specially directed to the change of resistance with change of temperature, and to an apparently permanent change in electric quality which the glass underwent when subjected to a high temperature. Subsequent experiments have served to confirm the results there given, but show that if the glass be newly made very little, if any, permanent change is brought about by heating.

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:—

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