SIGMAPLUG—A NEW TEMPERATURE INDICATOR FOR REMAINING LIFE ASSESSMENT OF HIGH TEMPERATURE COMPONENTS

Improved life assessment techniques will enable engineering components to be replaced before failure, thereby reducing the risk of industrial accidents as well as minimizing financial loss due to unscheduled outages. For components operating at high temperatures, temperature measurement is very important. In many situations, the environmental conditions are too hostile for conventional techniques to be used. Researchers over the world have been looking for new techniques for temperature measurement and one such device, called Feroplug, has been developed previously by the and coworkers. The Feroplug has been patented in USA, UK and Europe by the British Technology Group. The underlying principle of the Feroplug is based on the transformation of ferrite in some specially designed duplex stainless steels. This paper describes a new invention called Sigmaplug which is a new development of the Feroplug but using an entirely different physical principle. It was discovered that the sigma phase in Fe

Nanoindentation Characteristics of Cement Paste and Interfacial Transition Zone in Mortar with Rice Husk Ash

The nanostructure of cementitious materials has important effects on concrete properties. The effects of rice husk ash（RHA） on cement hydration product phases and interfacial transition zone（ITZ） in mortar were investigated from the nano-scale structure perspective. The experimental results indicate that, with the increase of RHA dosages of samples, the volume fraction of high-density calcium-silicate-hydrate（HD C-S-H） in porosity and hydration product phases increases. The volume fractions of HD C-S-H in C-S-H of samples show an increasing trend with the increase of RHA dosages. RHA decreases the thickness of ITZ and increases the matrix elastic moduli of samples, however, the RHA dosoges hardly affect the thickness and elastic moduli.

Rules essential for water molecular undercoordination

A sequential of concepts developed in the last decade has enabled a resolution to multiple anomalies of water ice and its low-dimensionality,particularly.Developed concepts include the coupled hydrogen bond(O:H–O)oscillator pair,segmental specific heat,three-body coupling potentials,quasisolidity,and supersolidity.Resolved anomalies include ice buoyancy,ice slipperiness,water skin toughness,supercooling and superheating at the nanoscale,etc.Evidence shows consistently that molecular undercoordination shortens the H–O bond and stiffens its phonon while undercoordination does the O:H nonbond contrastingly associated with strong lone pair“:”polarization,which endows the low-dimensional water ice with supersolidity.The supersolid phase is hydrophobic,less dense,viscoelastic,thermally more diffusive,and stable,having longer electron and phonon lifetime.The equal number of lone pairs and protons reserves the configuration and orientation of the coupled O:H–O bonds and restricts molecular rotation and proton hopping,which entitles water the simplest,ordered,tetrahedrally-coordinated,fluctuating molecular crystal covered with a supersolid skin.The O:H–O segmental cooperativity and specific-heat disparity form the soul dictate the extraordinary adaptivity,reactivity,recoverability,and sensitivity of water ice when subjecting to physical perturbation.It is recommended that the premise of“hydrogen bonding and electronic dynamics”would deepen the insight into the core physics and chemistry of water ice.

Nanostructured transition metal oxides as advanced anodes for lithium-ion batteries

The exploration for post-carbon electrode ma- terials for lithium-ion batteries has been a crucial way to satisfy the ever-growing demands for better performance with higher energy/power densities, enhanced safety, and longer cycle life. Transition metal oxides have recently re- ceived a great deal of attention as very promising anode materials due to their high theoretical capacity, good safety, eco-benignity, and huge abundance. The present work re- views the latest advances in developing novel transition metal oxides, including FeeO3, Fe3O4, CO3O4, CoO, NiO, MnO, Mn203, Mn3O4, MnO2, MOO3, Cr2O3, Nb2O5, and some binary oxides such as NiCO2O4, ZnCO2O4, MnCO2O4 and CoMn2O4. Nanostructuring and hybrid strategies ap- plicable to transition metal oxides are summarized and analyzed. Furthermore, the impacts of binder choice and heat treatment on electrochemical performance are discussed.

A density functional theory study of the tunable structure, magnetism and metal-insulator phase transition in VS2 monolayers induced by in-plane biaxial strain

We report a density functional theory study of a phase transition of a VS2 monolayer that can be tuned by the in-plane biaxial strain. This results in both a metal-insulator transition and a low spin-high spin magnetic transition. At low temperature, the semiconducting H-phase is stable and large strain （〉3%） is required to provoke the transition. On the other hand, at room temperature （300 K）, only a small tensile strain of 2% is needed to induce the phase transition from the semiconducting H-phase to the metallic T-phase together with the magnetic transition from high spin to low spin. The phase diagram dependence on both strain and temperature is also discussed in order to provide a better understanding of the phase stability of VS2 monolayers.

High‑Valence Transition Metal Modified FeNiV Oxides Anchored on Carbon Fiber Cloth for Efficient Oxygen Evolution Catalysis

Developing efficient and durable non-noble metal-based oxygen evolution catalysts is of great importance for electrochemical water splitting.Here,we report a new and facile strategy for controllable synthesis of high-valence Mo modified FeNiV oxides as efficient OER catalysts.The Mo-dopant displays a significant influence on the valence state of Fe species in the catalysts,which lead to tunable OER performance.When the feed ratio of Mo-dopant is 5%,the Mo-modified FeNiV oxide shows the best OER performance in terms of low overpotential(237 mV at the current density of 10 mA cm^(−2)),Tafel slope(38 mV per decade),and high mass activity,which exceeds its counterparts and most reported OER catalysts.Furthermore,by assembling the catalyst with a carbon fiber cloth,the fabricated water-splitting device exhibits excellent activity and longterm durability in alkaline electrolyte compared with commercial catalysts equipped device.This work not only provides a series of Mo-modified FeNiV-based oxides as high-performance OER catalysts but also offers a new pathway to tune the charge states of OER active centers.

Vibration-Induced Friction Temperature Field Analysis Under Different Working Condition of Heavy Load Bolt

Based on thermal-stress coupling analysis and material properties studies,the vibration-induced friction process of a special used heavy-load bolt has been simulated.The temperature distribution of the bolt has been calculate with heat radiation and heat convection considered.Also a solid lubricant,polytetrafluoroethylene (PTFE) has bee considered to reduce the friction heat effect.The result shows that,there are very strong heat effect while no lubracant considered,the temperature of the bolt joint increased sharply and up to 700℃,which exceed the allowable temperature range of the steel.When PTFE lubricant has been applied,the temperature of the bolt joint increased to 260 ℃,and the bolt steel can by applied in this satuation.These results provide important guidance for the bolt structure modification and material selection.

Intrinsic defects of nonprecious metal electrocatalysts for energy conversion: Synthesis, advanced characterization, and fundamentals

With the depletion of fossil fuels and environmental pollution, energy storage and conversion have become the focus of current research. Water splitting and fuel cell technologies have made outstanding contributions to energy conversion. However, the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) have slow kinetics, which limit the capacity of fuel cells. It is of great significance to develop catalysts for the OER and ORR and continuously improve their catalytic performance. Many studies have shown that intrinsic defects, especially vacancies (anion and cation vacancies), can effectively improve the efficiency of electrochemical energy storage and conversion. The introduction of intrinsic defects can generally expose more active sites, enhance conductivity, adjust the electronic state, and promote ion diffusion, thereby enhancing the catalytic performance. This review comprehensively summarizes the latest developments regarding the effects of intrinsic defects on the performance of non-noble metal electrocatalysts. According to the type of intrinsic defect, this article reviews in detail the regulation mechanism, preparation methods and advanced characterization techniques of intrinsic defects in different materials (oxides, non-oxides, etc.). Then, the current difficulties and future development of intrinsic defect regulation are analyzed and discussed thoroughly. Finally, the prospect of intrinsic defects in the field of electrochemical energy storage is further explored.