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It is of great concern to find out the factors determining charging densities. The authors have been engaged in experiments as to the relation between the application of additives and the charging density.
1. The loss of phenyl methyl silicone oil consists of dipole loss, space-charge loss and ionic conduction loss. 2. A specific loss peak of phenyl methyl silicone oil appearing at 10kHz below −40°C is not likely due to resonance absorption arising from the rotations and vibrations of atoms or ions in the crystal lattices.
Dielectric and Ultrasonic study of tert-butyl alcohol(TBA) and tert-amyl alcohol (TAA) in solution in non-polar solvents is done. The dipole moment is evaluated using ultrasonic velocity and compared with that obtained from dielectric studies. Using free volume, molar volume, the contribution of electronic polarizability, London dispersion forces and dipole dipole interaction are estimated. The non-linear...
The viscosity values may be fitted over the whole range 10−3 – 1012 by the Cohen Grest relation with great accuracy and a standard deviation less than 5 to 8 10−2. However to calculate the 4 C.G. - parameters it is necessary to get precise data over a large range of viscosities about 8 to 10 orders of magnitude. If it is not the case a 3-parameters equation as the VFTH relation may be sufficient for...
Streamer phenomena of both polarities have been evidenced under AC voltage in various experimental conditions. The use of various tip radiuses of curvature and inter-electrode distances has permitted to investigate a large range of applied voltages, and to check the conditions in which the streamers can or not propagate.
Photo-emission during the breakdown processes of an insulating oil is recorded and analyzed. A standard oil tester is used to energize the gap at a constant rate of rise of the applied ac voltage of 50 Hz. Standard spherical electrodes of a radius of 25 mm and a spacing of 1.75 mm are used. A laser beam is employed to adjust the inlet iris of a photo-multiplier telescope to the center point of the...
With the increase of the voltage level in the HU equipments, the behaviour of insulating ails must be better investigated under transitory stress conditions.
Electrical properties of grains and seeds have gained considerable significance with the advancement of new agricultural technology. Since, the grain & seed species belong to a group of biological materials which are of hygroscopic nature, measurement of their moisture content has attracted a wide attention. Microwave heating has introduced another aspect in the direction of food processing by...
New original method and experimental technique for visualisation and optical measurements of two-demensional conductivity distribution in dielectrics under high voltage pulses had been developed. Charge and current sensitivities about 10−14 C and 10−12 A respectivly had been obtained.
Living systems appear to be making use of the whole of the non-ionising electromagnetic spectrum for purposes of information transfer and regulation. Since they operate in an aqueous environment, the dielectric properties of water, lipids, macromolecules and hydrophi1lc-hydrophobic interfaces are also of importance over the whole spectrum.
A new method for the calculation of the solute dipole moment in the concentration range 1 % – 40 % at microwave frequencies is proposed. It is applied for the analysis of the dielectric data of chloral (CCl3-CHO) in solution in benzene at 9.8 GHz. The concentration dependence of the permittivity is fitted by the equation including linear and quadratic terms of the concentration. The dipole moment...
In spite of a very large dispersion of the experimental results due to the difficulties to make experiments in cryogenic liquids, the space charge convected by flows of such liquids seems to be independant of the Reynolds number, as it was predicted, and the influence of the diameter to be negligible for small values of this parameter. More, the always very high streaming currents observed in hydrogen...
Experimental relationships between pressure drop increase and heat transfer increase, as result of applying an electic field to forced convection heat transfer of oil in a circular tube, are presented as functions of current and applied voltage. A negative electric field results in more marked enhancement of heat transfer and pressure drop than a positive field at the same voltage. However, both heat...
A new general formula has been established by the author to explain the transport mechanism of electrons,ions and molecules in ionised saturated hydrocarbon groups and other liquids.
By means of Differential Scanning Calorimetry applied to w/o microemulsions, the experimental evidence has been obtained of the presence of two forms of water, namely, “free” and “interphasal” distinguished by the melting temperatures of, respectively, 273 K and 263 K. In the case of a w/hexadecane microemulsion, the above water con configurations give rise to two separate endotherms upon steady heating...
The technique of dielectric response of a medium loading a resonant cavity has been used successfully to monitor all phases of matter. In this work results will be given on the dielectric response of bound (vicinal) water in germinating wheat seeds (Fig. 1, 2), the dielectric response of select fluids as they change phase from solid↔liquid (Fig. 3, 4) a discussion will be given of how the technique...
The four studied oils have the same chemical structure and our results show that in spite of very different molecular chain lengths the Iliq. values and the photocurrent values measured under identical experimental conditions are almost the same. At present, we are extending our experiments to methyl-phenyl silicone oils and trying to verify if such a behaviour is also observed in this type of oils.
Monte Carlo calculations are presented of the molecular configurational behaviour of R1(CH2)nR2 where R1 and R2 are dipolar, which serve to determine average dipole moment, chain extension, etc. The techniques adopted are developments of the work by Noti Lal, et al, employing the Metropolis method to restrict the range of conformations needed in an exploration. The computions are particularly aimed...
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