Environmental effects on low cycle fatigue of 2024-T351 and 7075-T651 aluminum alloys

The environmental effects on the low cycle fatigue (LCF) behavior of 2024-T351 and 7075-T651 aluminum alloys were studied at room temperature. The specimens were subjected to identical LCF tests at strain ratio R of −1 and frequency of 5 Hz in three environments: vacuum, air and 1% NaCl solution of pH 2. A separate group of specimens was pre-corroded in 1% NaCl solution and then LCF-tested in air. Their strain–life relations and cyclic stress–strain responses were investigated and compared. Furthermore, the fracture surface morphology was evaluated to find the association of LCF behavior and fractographic features under different environmental conditions.     

Electric field induced enhancement in the interfacial charge transfer kinetics of a solid polymer electrolyte

A novel electrostatic method for preparing modified solid polymer electrolytes (SPEs) is reported. Application of an electric field on an evaporating mixture of KYNAR, ethylene carbonate (EC), propylene carbonate (PC) and LiPF₆ dissolved in tetra hydro furan (THF) resulted in a solid polymer electrolyte whose charge transfer resistance was at least an order of magnitude lower than that formed without the application of an electric field. We believe that the observed enhancement is probably due to an electric field induced orientation of dipoles in the polymer chain.     

Reduction of speckle noise from optical coherence tomography images using multi-frame weighted nuclear norm minimization method

In this paper, we propose a speckle noise reduction method for spectral-domain optical coherence tomography (SD-OCT) images called multi-frame weighted nuclear norm minimization (MWNNM). This method is a direct extension of weighted nuclear norm minimization (WNNM) in the multi-frame framework since an adequately denoised image could not be achieved with single-frame denoising methods. The MWNNM method exploits multiple B-scans collected from a small area of a SD-OCT volumetric image, and then denoises and averages them together to obtain a high signal-to-noise ratio B-scan. The results show that the image quality metrics obtained by denoising and averaging only five nearby B-scans with MWNNM method is considerably better than those of the average image obtained by registering and averaging 40 azimuthally repeated B-scans.     

Experimental investigation on radiation heat transfer properties degradation of (black nickel-coated aluminium) solar receiver tube material

In our previous research, we have studied the surface property degradation of the uncoated receiver tubes of solar water heater at elevated temperatures Logesh et al. [2017. “Experimental Investigation on Radiation Heat Transfer Properties Degradation of Aluminium Solar Receiver Tube Material.” International Journal of Ambient Energy 1–6]. In this study, the investigation is extended to property degradation of selective surface, black nickel-coated aluminium material. The selective surface has been investigated for its absorptivity (α) and emissivity (?) changes due to its exposure to sunlight at elevated temperatures. The duration of exposure ranges from 240 to 960?h; the properties are measured at four intervals in the selected range of exposure. The investigation is also carried out to find the temperature dependence nature of the heat transfer properties. The properties are measured at 10 temperature intervals for every period of exposure. The absorptivity (α) is found to be increased for the coated surface than the uncoated, whereas the emissivity (?) gets decreased for the same period of exposure.     

A Review of Deep Hydrodesulfurization Catalysis

The increasing importance of hydrodesulfurization (HDS) in petroleum processing in order to produce clean-burning fuels has led to a surge of research on the chemistry and engineering of HDS. Most of the earlier works are focused on catalyst characterization by physical methods; on low-pressure reaction studies of compounds like thiophene having relatively high reactivities; on process development; or on CoMo, NiMo, or NiW catalysts supported on alumina, often doped by fluorine or phosphorus. Almost all the reviews have concentrated on alumina-supported CoMo, NiMo, and NiW sulfide catalysts for hydrotreating. Even reviews that are not limited to the above catalytic systems essentially deal with studies of simple compounds like thiophene.     

Electroreduction of carbonyl compounds at a Ti/ceramic TiO<Subscript>2</Subscript> cathode

The use of Ti/ceramic TiO₂ cathode as an effective cathode material for the reduction of two ketones—cyclohexanone and benzalacetone (BA) are highlighted. Galvanostatic reduction of these ketones gave exclusively cyclohexanol and benzyl acetone (4-phenyl 2-butanone) as the corresponding hydrogenated products, as characterized from their boiling points and nmr spectra. Higher product yields were observed as compared to the reduction of the ketones at conventional cathode materials like lead under identical experimental conditions. Best conditions for the formation of products have been identified based on current density, temperature and acid strength. Cyclic voltammetry indicates a mechanism involving heterogeneous redox catalysis involving the surface fixed redox groups Ti⁴⁺/Ti³⁺. The reaction can be conveniently scaled up.     

A two-dimensional numerical simulation of oxide charge buildup inMOS transistors due to radiation

The authors have developed a time-dependent two-dimensional simulator in order to simulate charge trapping in silicon dioxide due to radiation. The Poisson and continuity equations are solved both in the oxide and the semiconductor. In addition, in order to simulate charge trapping, trap rate equations using first-order trapping kinetics are solved in the oxide. This paper contains the numerical methods used in the simulation and results obtained using this simulator. One of the main results of this simulation is the presence of a lateral variation in the radiation-induced oxide charge in an MOS transistor irradiated with a drain bias