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Hydrophobic Contact Angle and Surface Degradation of Epoxy Resin Compound with Silicon Rubber and Silica
Electrical and Electronic Engineering , 2012, DOI: 10.5923/j.eee.20120205.07
Abstract: Polymer insulating materials such as epoxy resin have been using in the distribution and transmission lines as outdoor insulator. Several advantages of using epoxy resin are its low density, better dielectric properties and it has higher volume resistivity than glass and ceramic. However, some weaknesses of epoxy resin are easily influenced by environmental factors such as humidity, ultraviolet radiation, acid rain and effect of contamination. Consequently, surface of insulator will easily damage due to electrical tracking which is indicated by surface tracking. To improve the dielectric properties such as hydrophobic contact angle then silicon rubber was compounded. In this paper to understand of silicon rubber influence on leakage current characteristics and hydrophobic contact angle of epoxy resin insulating materials have been analyzed. The tests were conducted using the Inclined-Planed Tracking (IPT) method according to IEC 60587:1984 standard with Ammonium Chloride (NH4Cl) as contaminant. Flow rate of contaminant was 0.3 ml/min and high voltage AC 3.5 kV 50 Hz was applied to the top electrode. The experimental results reveal that the hydrophobic contact angle, leakage current and surface degradation depend on the composition of silicon rubber. Silicon rubber was improving epoxy resin performance as insulator. Based on analysis it is found that epoxy resin with silicon rubber without silica sand offers the optimum surface tracking and erosion resistance. We conclude that silica sand doesn’t influence on leakage current characteristics.
TGA Analysis of Rubber Seed Kernel
Noorfidza Yub Harun,M.T. Afzal,Mohd Tazli Azizan
International Journal of Engineering , 2010,
Abstract: This project investigated the possibility of converting biomass wastes into solidfuels by undergoing torrefaction process. Rubber seed kernel was used toproduce torrefied material and the factors affecting torrefaction were investigated.Samples of rubber seed kernel were dried, ground, sieved, heated and cooled toobtain the torrefied material. It was found that minimum 30% of the moisturecontent was removed from its original value during torrefaction process. Almost100% of the calorific value in all the samples can be retained or increased by upto 10% from the original waste calorific value. The proximate analysis wascarried out using Thermo Gravimetric Analyzer (TGA) where rubber seed kernelsexhibited high fixed carbon region at the respective temperature. At the optimumcondition of temperature 280°C and particle size of 0.025 mm, the torrefiedmaterial produced is viable to be promoted at a larger scale.
Role of dislocations in scattering of charge carriers in mechanical polishing damaged layers of silicon wafers  [PDF]
Vladimir Yuryev
Physics , 2010, DOI: 10.1023/A:1009421825142
Abstract: Physical processes resulting in the anomalous (cubic) dependence of the small-angle IR scattering intensity from near-surface layers of mechanically polished silicon and germanium wafers on the photoexcitation power were revealed. It was shown that extended linear defects and dislocations in the damaged region contribute predominantly to carrier scattering.
CRACK REASON ANALYSIS OF DAMAGED CARBONITRIDED PART
Karin Kocúrová,Marián Hazlinger
Materials Engineering , 2010,
Abstract: The article deals with the analysis of a damaged part, which was designed for use in a mechanical clutch of a car. The crack in the part was found during the production inspection. The aim of metallographic and fractography analyses of the fracture surfaces was to discover the reasons for the crack. The reason for creating the crack was the formation of smaller cracks in the production during pressing process of the semiproduct. These cracks even grew after the following thermochemical treatment. The fracture was initiated during the straightening process of quenched part.
Modification of Operational Characteristics of Cold Curing Silicon Rubber  [PDF]
V. V. Trachevskyi, K. Yu. Ilina, V. E. Yaremenko, M. T. Kartel, Bo Wang
Journal of Materials Science and Chemical Engineering (MSCE) , 2019, DOI: 10.4236/msce.2019.77003
Abstract:
Technological aspects of modifying the operational characteristics of cold cured silicate rubbers have been developed. The effect of chromium oxide on the resistance of cold-curing silicone compounds to thermal aging, as well as on the physic mechanical properties and dielectric characteristics has been studied. The various content of ultrafine chromium oxide in cold-cured silicone compositions has been investigated, it’s optimal content in an amount of 2 - 5 mass at 100 mass, including low molecular weight rubber. Chromium oxide has been proven to improve the thermal stability of cold-cured silicone compositions. The manufacturing technology and component composition of the composition with high performance.
Parameters for the analysis of natural rubber drying
Tirawanichakul, S.,Sanai, S.,Sangwichien, C.,Tirawanicahkul, Y.
Songklanakarin Journal of Science and Technology , 2007,
Abstract: The purpose of this research was to study and develop a mathematical model of essential parameters affecting drying process in terms of equilibrium moisture content (EMC), apparent density, percentage ofvoid fraction, specific heat capacity and effective diffusion coefficient (D) for three kinds of natural rubber. Three raw natural rubber samples in this work used crumb rubber, rubber stick and rubber sheet with aninitial moisture content ranging between 30 and 45% wet-basis that were normally used for producing the standardized Thai rubber (STR) block rubber and air dried rubber sheet (ADS). The results show that theapparent density and specific heat of all natural rubber samples were linearly dependent on the moisture content whilst the percentage of void fraction of natural rubber was inversely related to moisture content.The isotherm EMC equations formulated by the Herderson model for the crumb rubber and rubber stick were the best fitting with the experimental values, and for the rubber sheet. The isotherm EMC equationusing the Halsey model was the most appropriable to the experimental results. In addition, the effective diffusion coefficients of all natural rubber materials, which were the function of drying temperature and drying time, were in range of 10-6-10-7 m2/hr. However, prediction of the evolution of moisture content ofthin-layer drying under the condition of drying temperatures of 40-70oC (rubber stick and rubber sheet) and 100-130oC (crumb rubber) could be explained by the empirical model, which was the function of drying temperature and drying time.
The Garden-Hose Model  [PDF]
Harry Buhrman,Serge Fehr,Christian Schaffner,Florian Speelman
Computer Science , 2011, DOI: 10.1145/2422436.2422455
Abstract: We define a new model of communication complexity, called the garden-hose model. Informally, the garden-hose complexity of a function f:{0,1}^n x {0,1}^n to {0,1} is given by the minimal number of water pipes that need to be shared between two parties, Alice and Bob, in order for them to compute the function f as follows: Alice connects her ends of the pipes in a way that is determined solely by her input x \in {0,1}^n and, similarly, Bob connects his ends of the pipes in a way that is determined solely by his input y \in {0,1}^n. Alice turns on the water tap that she also connected to one of the pipes. Then, the water comes out on Alice's or Bob's side depending on the function value f(x,y). We prove almost-linear lower bounds on the garden-hose complexity for concrete functions like inner product, majority, and equality, and we show the existence of functions with exponential garden-hose complexity. Furthermore, we show a connection to classical complexity theory by proving that all functions computable in log-space have polynomial garden-hose complexity. We consider a randomized variant of the garden-hose complexity, where Alice and Bob hold pre-shared randomness, and a quantum variant, where Alice and Bob hold pre-shared quantum entanglement, and we show that the randomized garden-hose complexity is within a polynomial factor of the deterministic garden-hose complexity. Examples of (partial) functions are given where the quantum garden-hose complexity is logarithmic in n while the classical garden-hose complexity can be lower bounded by n^c for constant c>0. Finally, we show an interesting connection between the garden-hose model and the (in)security of a certain class of quantum position-verification schemes.
Modeling and Numerical Simulations with Compressible Damaged Hyperelastic Law: Application to the Laminated Rubber Bearing  [PDF]
Maha Zaghdoudi, Zohra Gaiech, Lamia Bejaoui, Zoubeir Tourki, Adnane Boukamel
Materials Sciences and Applications (MSA) , 2012, DOI: 10.4236/msa.2012.311119
Abstract: Hyperelastic model with damage induced compressibility is implemented in the ABAQUS software using the subrou- tine Umat. A thermodynamic model is proposed taking into account the nonlinearity of the material behavior. Within the present work, the behavior of laminated rubber bearing structure is studied for two geometrical sets of materials (A-type and equivalent material) under complex monotonic loading conditions. A new geometric edge of laminated rubber bearing is proposed in order to reduce the development costs of the structure. The proposed model allowed finding a good homogenized damage distribution for the same overall stiffness.
Dynamic analysis of damaged masonry building repaired with the flexible joint method
A. Kwiecień, P. Kuboń
Archives of Civil Engineering , 2012, DOI: 10.2478/v.10169-012-0003-2
Abstract: The paper presents a dynamic analysis of the damaged masonry building repaired with the Flexible Joint Method. Numerical analysis helped to determine the effect of the applied repairing method on natural frequencies as well as values of stresses and accelerations in the analyzed variants of numerical model. They confirmed efficiency of the proposed repair method.
The NuMI Hadronic Hose  [PDF]
R. Ducar,J. Hylen,V. Garkusha,C. Jensen,S. Kopp,M. Kostin,A. Lyukov,M. May,M. Messier,R. Milburne,F. Novoskoltsev,D. Pushka,W. Smart,G. Unel,J. Walton,V. Zarucheisky,R. Zwaska
Physics , 2001,
Abstract: The Neutrinos at the Main Injector (NuMI) beam supplies an intense $\nu_{\mu}$ beam to the Main Injector Neutrino Oscillation Search (MINOS). The $\nu_{\mu}$'s are derived from a secondary $\pi^+$ beam that is allowed to decay within a 675 m decay tunnel. As part of this effort, we are developing a continuous toroidal magnetic focusing system, called the Hadronic Hose, to better steer the secondary beam. The Hose will both increase the net neutrino flux reaching the MINOS detectors and reduce systematic differences in the neutrino energy spectra at the two detectors due to solid angle acceptances.
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