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.     

Green synthesized Au–Ag bimetallic nanoparticles modified electrodes for the amperometric detection of hydrogen peroxide

Simple and eco-friendly electro deposition method was employed for the fabrication of Au–Ag bimetallic nanoparticles modified glassy carbon electrode. Nano Au–Ag film modified glassy carbon electrode surface morphology has been examined using atomic force microscopy. Electrodeposited Au–Ag bimetallic nanoparticles were found in the average size range of 15–50 nm. The electrochemical investigations of nano Au–Ag/1-butyl-3-methylimidazolium tetrafluoroborate-nafion film have been carried out using cyclic voltammetry and electrochemical impedance spectroscopy. The nano Au–Ag/1-butyl-3-methylimidazolium tetrafluoroborate-nafion film modified glassy carbon electrode holds the good electrochemical behavior and stability in pH 7.0 phosphate buffer solutions. The nano Au–Ag/1-butyl-3-methylimidazolium tetrafluoroborate-nafion modified glassy carbon electrode was successfully employed for the detection of H₂O₂ in the linear range of 1–250 μM in lab samples, and 1 × 10⁻³–2 × 10⁻² M in real samples, respectively.     

An Expressively Complete Linear Time Temporal Logic for Mazurkiewicz Traces

A basic result concerning LTL, the propositional temporal logic of linear time, is that it is expressively complete; it is equal in expressive power to the first order theory of sequences. We present here a smooth extension of this result to the class of partial orders known as Mazurkiewicz traces. These partial orders arise in a variety of contexts in concurrency theory and they provide the conceptual basis for many of the partial order reduction methods that have been developed in connection with LTL-specifications.We show that LTrL, our linear time temporal logic, is equal in expressive power to the first order theory of traces when interpreted over (finite and) infinite traces. This result fills a prominent gap in the existing logical theory of infinite traces. LTrL also constitutes a characterisation of the so-called trace consistent (robust) LTL-specifications. These are specifications expressed as LTL formulas that do not distinguish between different linearisations of the same trace and hence are amenable to partial order reduction methods.     

Overview and perspectives of solid electrolytes for sodium batteries

Quoting the abundance and cost of sodium reserve and robustly safe and high-energy solid electrolytes, sodium solid-state batteries (SSBs) exhibit huge promise for future energy storage applications compared to battery systems using organic liquid electrolytes and Li counterparts. However, the progress and application are still in infancy, experiencing numerous challenges for sodium SSBs due to inherent properties, interface complications, and fabrication. These are recently receiving unprecedented research attention by understanding and steadily resolving the issues associated with sodium SSBs. In this review, the governing bulk and interfacial issues and dynamics, background research correlations from Li counterparts, and strategies to address them are investigated for various ceramic-, polymer-, and ceramic–polymer composite based solid electrolytes. Particular attention is devoted to issues with ceramic electrolytes (such as interfacial stability, brittleness, porosity, and grain–grain boundary resistance) and polymer electrolytes (like dendrite formation, passivation layer, electrochemical instability, and ionic conductivity), and finally, robustness in overall performance and a few drawbacks (such as filler agglomeration, interface dynamics, and crack propagation) on the composited state-of-the-art ceramic–polymer electrolytes are highlighted. To end with, crucial inferences and future research perspectives are condensed on the development of enhanced solid electrolytes for sodium SSBs overcoming the shortcomings illustrated for different electrolytes.     

Ultrafast Electron–Phonon Coupling at Metal-Dielectric Interface

Energy transfer from photo-excited electrons in a metal thin film to the dielectric substrate is important for understanding the ultrafast heat transfer process across the two materials. Substantial research has been conducted to investigate heat transfer in a metal-dielectric structure. In this work, a two-temperature model in metal was used to analyze the interface electron and dielectric substrate coupling. An improved temperature and wavelength-dependent Drude–Lorentz model was implemented to interpret the signals obtained in optical measurements. Ultrafast pump-and-probe measurements on Au-Si samples were carried out, where the probe photon energy was chosen to be close to the interband transition threshold of gold to minimize the influence of non-equilibrium electrons on the optical response and maximize the thermal modulation to the optical reflectance. Electron-substrate interface thermal conductance at different pump laser fluences was obtained, and was found to increase with the interface temperature.     

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.