Influence of temperature and moisture on the electrical properties of leather

Weir, C. E.

doi:10.6028/jres.048.044

Cited by 7 publications

(2 citation statements)

References 23 publications

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“…The hide is also similar but it is dead animal tissue having a complex microscopic structure. The electrical impedance in this case is expected to have frequency dependence (Weir 1952). However, at a particular frequency of measurement, it will offer a fixed value of impedance.…”

Section: Type Of the Materials (Density)mentioning

confidence: 99%

Determination of abdominal fat thickness using dual electrode separation in the focused impedance method (FIM)

et al. 2012

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Subcutaneous fat layer thickness in the abdomen is a risk indicator of several diseases and disorders like diabetes and heart problems and could be used as a measure of fitness. Skinfold measurement using mechanical calipers is simple but prone to error. Ultrasound scanning techniques are yet to be established as accurate methods for this purpose. magnetic resonance imaging (MRI) and computed tomography (CT) scans can provide the answer but are expensive and not available widely. Some initiatives were made earlier to use electrical impedance to this end, but had inadequacies. In the first part of this paper, a 4-electrode focused impedance method (FIM) with different electrode separations has been studied for its possible use in the determination of abdominal fat thickness in a localized region. For this, a saline phantom was designed to provide different electrode separations and different layers of resistive materials adjacent to the electrodes. The background saline simulated the internal organs having low impedance while the resistive layers simulated the subcutaneous fat. The plot of the measured impedance with electrode separation had different 'slopes' for different thicknesses of resistive layers, which offered a method to obtain an unknown thickness of subcutaneous fat layer. In the second part, measurements were performed on seven human subjects using two electrode separations. Fat layer thickness was measured using mechanical calipers. A plot of the above 'slope' against fat thickness could be fitted using a straight line with an R(2) of 0.93. Then this could be used as a calibration curve for the determination of unknown fat thickness. Further work using more accurate CT and MRI measurements would give a better calibration curve for practical use of this non-invasive and low-cost technique in abdominal fat thickness measurement.

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Section: Type Of the Materials (Density)mentioning

confidence: 99%

Determination of abdominal fat thickness using dual electrode separation in the focused impedance method (FIM)

et al. 2012

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“…I n our case the electrostatic contribution to free energy of dissociation is slightly temperature-dependent because of the temperature-dependency of the dielectric constant. 8 It appears that the entropy is related t o enthalpy, if the dielectric constant obeys the relation (8).…”

Section: Mechanism Of Protonic Conductionmentioning

confidence: 99%

Electrical conduction in hydrated collagen. I. Conductivity mechanisms

Bardelmeyer

1973

Biopolymers

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SynopsisThe electrical conductivity of bovine Achilles tendon with various amounts of adsorbed water was measured as a function of temperature. The conduction appeared t.0 be fully determined by the water of hydration. The current is probably primarily carried by protons a t water contents up to 45% and by small ions a t water contents beyond 65%. In both ranges of water content, a linear relation between activation energy and water content was found. As to the lower range, this is explained by the action of Coulombic forces during the separation of protonshydroxyl ion pairs. In two regions of water content a linear relation between the logarithm of the pre-exponential factor and the activation energy was found. There are, however, no indications that a compensation effect is responsible for this observation. It is concluded that at certain water contents the dissociation constant of the adsorbed water is several orders of magnitude higher than in liquid water.

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Dielectric properties of slightly hydrated collagen: Time–water content superposition analysis

Sasaki¹

1984

Biopolymers

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SynopsisThe frequency dependences of the dielectric constant, E ' , and the loss factor, E", in collagen were measured a t several water contents from 0.1 to 0.3 g/g collagen over a frequency range of 30 Hz to 100 kHz and at a temperature of 20°C. Remarkable dispersion was observed at the lower frequencies for higher water contents. According to accumulated results on the thermodynamic and structural investigations, the dispersion has some analogy to the surface conduction proposed by B. V. Hamon [(1953) Awt. J. Phys. 6, 304-3151. An empirical relation bewteen E" and frequency, E"= f", where 0 < n < 1, suggests that the dielectric and conductive properties of hydrated collagen are related to carrier jumps between neighboring sites. For the polarization mechanism of this dispersion, we supposed a model of the transfer of protons between absorbed water molecules, and found that the t i m e w a t e r content superposition procedure is applicable to slightly hydrated collagen. The results derived from the superposition procedure show that the water content, +, is related to the conductivity, r , or the dielectric loss factor by the following equations: r (+, f , = const. x +,zm-lf' and el' (+, f, = const.+""'f", respectively, where rn is a constant independent of + and f: These results agree with that derived by another treatment of the same data. The role of water molecules in the conduction and polarization in slightly hydrated collagen is considered to be not far from that assumed in the model.

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Influence of temperature and moisture on the electrical properties of leather

Cited by 7 publications

References 23 publications

Determination of abdominal fat thickness using dual electrode separation in the focused impedance method (FIM)

Determination of abdominal fat thickness using dual electrode separation in the focused impedance method (FIM)

Electrical conduction in hydrated collagen. I. Conductivity mechanisms

Dielectric properties of slightly hydrated collagen: Time–water content superposition analysis

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