Densification and Properties of α-Silicon Carbide

Densification of a-Sic powders with no premixed sintering aids (type 1) and with premixed B and C (type 2) was investigated by sintering them at 2150° to 2200°C for 30 min. Flexure strengths, Weibull moduli, and fracture flaws were characterized for type 2 α-SiC only. The results were compared with those for a state-of-the-art sintered a-Sic material.     

Surface tailoring of an ethylene propylene diene elastomeric terpolymer via plasma‐polymerized coating of tetramethyldisiloxane

In the research presented here, we explore the use of a low‐energy plasma to deposit thin silicone polymer films using tetramethyldisiloxane (TMDSO) (H(CH₃)₂? Si? O? Si? (CH₃)₂H) on the surface of an ethylene propylene diene elastomeric terpolymer (EPDM) in order to enhance the surface hydrophobicity, lower the surface energy and improve the degradation/wear characteristics. The processing conditions were varied over a wide range of treatment times and discharge powers to control the physical characteristics, thickness, morphology and chemical structure of the plasma polymer films. Scanning electron microscopy (SEM) shows that pore‐free homogeneous plasma polymer thin films of granular microstructure composed of small grains are formed and that the morphology of the granular structure depends on the plasma processing conditions, such as plasma power and time of deposition. The thicknesses of the coatings were determined using SEM, which confirmed that the thicknesses of the deposited plasma‐polymer films could be precisely controlled by the plasma parameters. The kinetics of plasma‐polymer film deposition were also evaluated. Contact angle measurements of different solvent droplets on the coatings were used to calculate the surface energies of the coatings. These coatings appeared to be hydrophobic and had low surface energies. X‐ray photoelectron spectroscopy (XPS) and photoacoustic Fourier‐transform infrared (PA‐FT‐IR) spectroscopy were used to investigate the detailed chemical structures of the deposited films. The optimum plasma processing conditions to achieve the desired thin plasma polymer coatings are discussed in the light of the chemistry that takes place at the interfaces. Copyright © 2004 Society of Chemical Industry     

Heat transfer from a stretching sheet with uniform suction and blowing

Summary The conjugate problem of heat transfer from an accelerating surface in presence of suction and blowing has been solved analytically. The effects of different parameters on cooling of the surface have been discussed.With 3 Figures     

Extensive Study of Underlap Length Effect for 3-D SOI FinFET to Achieve High Switching Ratio and Low Power

Silicon - The primary purpose of this work is to study the effect of symmetric and asymmetric variation of underlap regions both on source and drain side of 3D SOI n-FinFET. Underlap length is...     

IndoorSense: context based indoor pollutant prediction using SARIMAX model

Multimedia Tools and Applications - Indoor air pollutants e.g., Carbon dioxide (CO2), Particulate Matter(PM)2.5, PM10, Total Volatile Organic Compounds (TVOC), etc. have a serious impact on human...     

A study of the immobilization of strontium over crystalline titania

The immobilization of strontium over titania was carried out by the method of coprecipitation. From a preliminary study, an appreciable uptake (52.8%) of⁹⁰Sr was observed over preformed titania material. A weighable amount of strontium was coprecipitated with Ti(IV) hydroxide and a maximum of 34 wt% Sr was found to be adsorbed. The leachability of the mixed materials prepared by the addition of 250 and 400 mg Sr²⁺, calcined at 1000 °C, by soxhlet apparatus refluxing at 97 °C and repeated seven times at intervals of 24 h, was found to be of the order of 10^–9 and 10^–5 g cm^–2 d^–1, respectively. X-ray powder diffraction analysis revealed that strontium was immobilized in the crystalline matrix of rutile, which suffered some structural changes with the formation of new phases, SrTiO₃+Sr₂TiO₄ and SrTiO₃, respectively.     

Adaptive broadcast by fault-tolerant spanning tree switching

Adaptation is a desirable requirement in a distributed system as it helps the system to perform efficiently under different environments. For many problems, more than one protocol exists, such that one protocol performs better in one environment while the other performs better in another. In such cases, adaptive distributed systems can be designed by dynamically switching between the protocols as the environment changes. Distributed protocol switching is also important for performance enhancement, or fault-tolerance of a distributed system. In this work, we illustrate distributed protocol switching by providing a distributed algorithm for adaptive broadcast that dynamically switches from a BFS tree to a DFS tree. The proposed switching algorithm can also handle arbitrary crash failures. It ensures that switching eventually terminates in spite of failures and the desired tree (DFS tree) results as the output. We also investigate the properties that can be guaranteed on the delivery of broadcast messages under specific failure conditions. We show that under no failure, each broadcast message is eventually correctly delivered to all the nodes in spite of switching. Under arbitrary crash fault, we ensure that switching eventually terminates with the desired tree as the broadcast topology. We also investigate the specific delivery guarantees that can be provided when a single crash fault happens, both during switching and when no switching is in progress.     

Attribute-based key-insulated signature for boolean formula

In order to minimize the impact of secret signing key exposure in attribute-based signature scenario, we construct an attribute-based key-insulated signature (ABKIS) scheme for expressive monotone boolean function access structures utilizing only four pairing operations in verification process and making the signature length constant, that is, the number of pairings required for signature verification and the size of signature are independent of the size of attribute set participated in the respective process. The (strong) key-insulated selective security of our ABKIS scheme is reduced to the computational Diffie–Hellman Exponent problem without using any random oracles. The proposed construction attains signer privacy, which is a fundamental requirement of the signature schemes in the attribute-based setting.