Radiofrequency Heating of Rubber and Carbon Black Mixes

1968 ◽  
Vol 41 (5) ◽  
pp. 1219-1230
Author(s):  
N. H. Langton
Keyword(s):  
Simple Model ◽  
Carbon Black ◽  
Breakdown Voltage ◽  
Random Distribution ◽  
Reliable Data ◽  
Experimental Results ◽  
Dielectric Heating ◽  
Radiofrequency Heating ◽  
Uniform Array

Abstract In conclusion, the simple model of a uniform array of spherical conducting particles of negligible size, when modified for a random distribution, enables predictions as to the maximum permissible loading of carbon black in a rubber/black mix that can be heated by dielectric heating without breakdown. The theory agrees qualitatively with the results of Gehman's theory of random filler dispersions. It is not possible to compare values given by the theory with experimental results, because there is no reliable data giving breakdown voltage figures for rubber/black mixes of known dispersion. However predictions given by the theory agree qualitatively with experiments.

scholarly journals A Novel Gate Drive Circuit for Suppressing Turn-on Oscillation of Non-Kelvin Packaged SiC MOSFET

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2449
Author(s):  
Hongyan Zhao ◽  
Jiangui Chen ◽  
Yan Li ◽  
Fei Lin
Keyword(s):  
Thermal Conductivity ◽  
Breakdown Voltage ◽  
Basic Principle ◽  
Double Pulse ◽  
Experimental Results ◽  
Switching Frequency ◽  
Turn On ◽  
Proof Testing ◽  
Gate Driver ◽  
Drive Circuit

Compared with a silicon MOSFET device, the SiC MOSFET has many benefits, such as higher breakdown voltage, faster action speed and better thermal conductivity. These advantages enable the SiC MOSFET to operate at higher switching frequencies, while, as the switching frequency increases, the turn-on loss accounts for most of the loss. This characteristic severely limits the applications of the SiC MOSFET at higher switching frequencies. Accordingly, an SRD-type drive circuit for a SiC MOSFET is proposed in this paper. The proposed SRD-type drive circuit can suppress the turn-on oscillation of a non-Kelvin packaged SiC MOSFET to ensure that the SiC MOSFET can work at a faster turn-on speed with a lower turn-on loss. In this paper, the basic principle of the proposed SRD-type drive circuit is analyzed, and a double pulse platform is established. For the purpose of proof-testing the performance of the presented SRD-type drive circuit, comparisons and experimental verifications between the traditional gate driver and the proposed SRD-type drive circuit were conducted. Our experimental results finally demonstrate the feasibility and effectiveness of the proposed SRD-type drive circuit.

Constitutive modeling for the mechanical behavior of rubber with filler particles

2021 ◽  
Author(s):  
Sankalp Gour ◽  
Deepu Kumar Singh ◽  
Deepak Kumar ◽  
Vinod Yadav
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
Mechanical Behavior ◽  
Experimental Observation ◽  
Continuum Mechanics ◽  
Constitutive Modeling ◽  
Carbon Nanoparticles ◽  
Material Behavior ◽  
Experimental Results ◽  
Filler Particles

Abstract The present study deals with the constitutive modeling for the mechanical behavior of rubber with filler particles. An analytical model is developed to predict the mechanical properties of rubber with added filler particles based on experimental observation. To develop the same, a continuum mechanics-based hyperelasticity theory is utilized. The model is validated with the experimental results of the chloroprene and nitrile butadiene rubbers filled with different volume fractions of carbon black and carbon nanoparticles, respectively. The findings of the model agree well with the experimental results. In general, the developed model will be helpful to the materialist community working in characterizing the material behavior of tires and other rubber-like materials.

scholarly journals Measurement of Photon Buildup Factor for Samples of Iraqi Carbon Black Material

2016 ◽  
Vol 8 (2) ◽  
pp. 444-450
Author(s):  
Baghdad Science Journal
Keyword(s):  
Carbon Black ◽  
Experimental Results ◽  
Buildup Factor ◽  
Mixing Ratio ◽  
Black Powder ◽  
Mixing Ratios ◽  
Carbon Black Powder ◽  
Expected Values

The buildup factor was measured after irradiating Iraq carbon black powder using each of and sources respectively, using mixing ratios 40% & 50% for thickness range . The results showed that the buildup factor depends on energy and has limited dependence on the mixing ratio. The QIFT program succeeded accenting for the experimental results even for expected values more than 4 m.f.p outside the thickness range.

The 3D graph approach for breakdown voltage calculation in BaTiO3 ceramics

2021 ◽  
pp. 2150103
Author(s):  
Vojislav V. Mitic ◽  
Branislav Randjelovic ◽  
Ivana Ilic ◽  
Srdjan Ribar ◽  
An-Lu Chun ◽  
...  
Keyword(s):  
Graph Theory ◽  
Crystal Structures ◽  
Breakdown Voltage ◽  
Main Idea ◽  
Experimental Results ◽  
Grain Structure ◽  
Mathematical Approach ◽  
Electronic Parameters ◽  
Mathematical Graph

After pioneering attempts for the introduction of graph theory in the field of ceramics and microstructures, where 1D and 2D graphs were used, in this paper we applied 3D graphs for the breakdown voltage calculation in BaTiO3 sample with some predefined constraints. We have described the relations between grains in the sample and established a mathematical approach for the calculation of breakdown voltage using experimental results. As a result, we introduced mapping between the property of sample and grain structure, then between the grain structure and mathematical graph, using various crystal structures. The main idea was to apply 3D graph theory for the distribution of electronic parameters between the neighboring grains. With this study, we successfully confirmed the possibilities for applications of graphs as a tool for the determination of properties even at the intergranular level.

scholarly journals Modelling of ‘sub-atomic’ contrast resulting from back-bonding on Si(111)-7×7

2016 ◽  
Vol 7 ◽  
pp. 937-945 ◽  
Author(s):  
Adam Sweetman ◽  
Samuel P Jarvis ◽  
Mohammad A Rashid
Keyword(s):  
Simple Model ◽  
Experimental Results ◽  
Striking Similarity ◽  
Orbital Structure ◽  
Dangling Bond ◽  
Lennard Jones ◽  
Detailed Explanation ◽  
Afm Imaging ◽  
Back Bonding ◽  
Molecular Contrast

It has recently been shown that ‘sub-atomic’ contrast can be observed during NC-AFM imaging of the Si(111)-7×7 substrate with a passivated tip, resulting in triangular shaped atoms [Sweetman et al. Nano Lett. 2014, 14, 2265]. The symmetry of the features, and the well-established nature of the dangling bond structure of the silicon adatom means that in this instance the contrast cannot arise from the orbital structure of the atoms, and it was suggested by simple symmetry arguments that the contrast could only arise from the backbonding symmetry of the surface adatoms. However, no modelling of the system has been performed in order to understand the precise origin of the contrast. In this paper we provide a detailed explanation for ‘sub-atomic’ contrast observed on Si(111)-7×7 using a simple model based on Lennard-Jones potentials, coupled with a flexible tip, as proposed by Hapala et al. [Phys. Rev. B 2014, 90, 085421] in the context of interpreting sub-molecular contrast. Our results show a striking similarity to experimental results, and demonstrate how ‘sub-atomic’ contrast can arise from a flexible tip exploring an asymmetric potential created due to the positioning of the surrounding surface atoms.

scholarly journals Charge Injection Characteristics of Semi-Conductive Composites with Carbon Black-Polymer for HVDC Cable

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1134 ◽  
Author(s):  
Yanhui Wei ◽  
Mingyue Liu ◽  
Wang Han ◽  
Guochang Li ◽  
Chuncheng Hao ◽  
...  
Keyword(s):  
Carbon Black ◽  
Electric Field ◽  
Bottom Electrode ◽  
Charge Injection ◽  
Experimental Results ◽  
Uniform Electric Field ◽  
Insulation Material ◽  
Electrode Structure ◽  
Depolarization Current ◽  
Conductive Composites

Semi-conductive composites composed of carbon black-polymer play an important role in uniform electric field in high voltage direct current (HVDC) cable. They also affect space charge behaviors in the insulation material. However, the charge injection characteristics of semi-conductive composites are not detailed. In this work, the electrode structure of ‘Semi-conductive composites- Insulation material- Metal bottom’ (S-I-M) is proposed, and the currents formed by injected charges from semi-conductive composites are characterized by the thermally stimulated depolarization current (TSDC) method. Further, the experimental results based on the structure of S-I-M are compared with the traditional electrode structure of M-I-M (Metal upper electrode- Insulation material- Metal bottom electrode) and the simplified cable electrode structure of MS-I-M (Metal upper electrode-Semi-conductive electrode- Insulation material- Metal bottom electrode), respectively. The experimental results show that the semi-conductive composite plays an important role in the charge injection process and it presents a different tendency under different compound modes of temperature and electric field. For the low electric field (E ≤ 5 kV/mm) and the low temperature (T ≤ 50 °C), the current caused by the accumulated charges follows the rule, IS > IMS > IM. For the low electric field and high temperature (T > 50 °C), the current caused by the injected charges follows the rule, IMS > IM > IS. This phenomenon is closely related to the interface characterization and contact barrier.

The dependence of the sputtering ratio of polycrystalline metals on the angle of ion incidence on the target

1968 ◽  
Vol 46 (6) ◽  
pp. 779-782 ◽  
Author(s):  
I. N. Evdokimov ◽  
V. A. Molchanov
Keyword(s):  
Simple Model ◽  
Beam Energy ◽  
Ion Beam ◽  
Target Surface ◽  
Close Packing ◽  
Experimental Results ◽  
Polycrystalline Metals

The sputtering ratio of polycrystalline metals as well as the amount of ion beam energy reflected from the target surface showed angular behavior which was not monotonic at large angles of incidence. The simple model which takes into account "close-packing" at the target surface and, consequently, more or less ordered shadowing of the surface atoms seems to describe the experimental results qualitatively.

Solubility of Sulfur and Dithiocarbamates in Natural Rubber

1995 ◽  
Vol 68 (5) ◽  
pp. 794-803 ◽  
Author(s):  
M. D. Morris ◽  
A. G. Thomas
Keyword(s):  
Natural Rubber ◽  
Experimental Method ◽  
Interaction Parameter ◽  
Reliable Data ◽  
Experimental Results ◽  
Heat Of Fusion ◽  
Latent Heat Of Fusion ◽  
Degree Of Swelling ◽  
Zinc Diethyldithiocarbamate ◽  
Adequate Method

Abstract Knowledge of equilibrium solubilities of sulfur and accelerators in rubbers at various temperatures allows prediction of whether blooming is possible in particular compounds or products. Reliable data of this nature for natural rubber appeared not to exist in the literature. Immersion of 1 mm thick sheets of peroxide-vulcanized natural rubber in both liquid and, more surprisingly, powdered solid curatives was found to be an adequate method for measuring solubilities. The same experimental method also enabled some diffusion data to be obtained. Solubilities of sulfur, zinc diethyldithiocarbamate (ZDEC) and zinc di-n-butyl dithiocarbamate (ZDBC) were determined at various temperatures between 23° and 135°C. The experimental results did not agree well with the theory which had previously been found to describe the solubility of waxes in natural rubber. This theory, which is a combination of the Flory-Huggins Equation with an expression for the latent heat of fusion, was modified to take into account the dependence of the interaction parameter on temperature and on degree of swelling. The new expression gave much better agreement with the experimental results for all three substances.

BREAKDOWN OF A RADIO-FREQUENCY DISCHARGE IN THE PRESENCE OF A SUPERIMPOSED d-c. FIELD

1965 ◽  
Vol 43 (8) ◽  
pp. 1543-1551 ◽  
Author(s):  
S. N. Sen ◽  
B. Bhattacharjee
Keyword(s):  
Radio Frequency ◽  
Breakdown Voltage ◽  
Experimental Results ◽  
Breakdown Field ◽  
Theoretical Expression ◽  
Rare Gases ◽  
Field Frequency ◽  
Radio Frequency Field ◽  
Frequency Field ◽  
Positive Ions

Breakdown voltages have been determined in the case of some rare gases (He, Ne, A) and oxygen at a constant pressure (10 mm Hg) when excited simultaneously by a radio-frequency field (frequency 10 Mc/sec) and a variable d-c. field. It is found in all cases that the breakdown voltage is higher when both the fields are present than when the gases are excited by the radio-frequency field alone and the breakdown voltage gradually increases with the increase of the applied d-c. field. The variation of breakdown field with d-c. field is of the same nature in all of the gases studied. A theoretical expression for the breakdown voltage in the presence of both the r-f. and d-c. fields has been deduced from the theory of electrical discharge by Kihara (1952) together with the expression of equivalent length as deduced by Varnerin and Brown (1950). The theoretical expression cannot explain satisfactorily the experimental results, and the rate of rise of breakdown voltage in the d-c. field as obtained from theory is smaller than that obtained from experimental results. The discrepancy has been ascribed partly to the uncertainty in the values of the numerical constants introduced by Kihara and also to the increase of diffusion caused by the presence of positive ions—a factor which has not been taken into consideration in the present treatment.

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