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The study focuses on testing a simplified way of estimating the resultant force due to ballistic impacts resulting in a full fragmentation of the impactor with no penetration of the target. The method is intended to be useful for the parsimonious structural assessment of military aircrafts with integrated ballistic protection systems by means of large scale explicit finite element simulations. The research investigates the effectiveness of the method in allowing the prediction of the fields of plastic deformation collected by hard steel plates impacted by a wide range of semi-jacketed, monolithic, and full metal jacket.308 Winchester rifle bullets. The outcomes show the effectiveness of the method being strictly related to the full compliance of the considered cases with the bullet-splash hypotheses. The study therefore suggests the application of the load history approach only after careful experimental investigations on the specific impactor–target interactions. [ABSTRACT FROM AUTHOR]

In the science and technology of electrochemical energy storage, different allotropes of MnO2, fabricated with a variety of methods, are assembled into electrodes, playing the role of cathode or oxygen reduction reaction (ORR) electrocatalyst. Often, MnO2‐based cathodes are combined with Zn anodes into different types of batteries, resulting in contact between MnO2 and its electrochemical reaction products, and Zn2+. Awareness is growing that this interaction adversely affects the functional performance of MnO2, but no definitive understanding has been reached for this issue. This study contributes, through electrochemical measurements accompanied by microscopy and Raman spectroscopy, to a better understanding of the way the electrochemical behavior of two technologically representative types of manganese dioxide ‐ hydrothermally grown α‐MnO2 and electrodeposited γ‐MnO2 (EDM) ‐ is degraded when these materials are exposed to neutral and alkaline aqueous solutions, containing Zn2+. Specifically, we highlighted different types of irreversible changes in electrochemical response, which can be interpreted with phase‐formation processes. Such changes result in the deactivation of α‐MnO2 as ORR electrocatalyst, and of both α‐MnO2 and EDM as zinc‐ion battery (ZIB) cathodes. The electroactivity of EDM for ZIB operation can be restored if Mn2+ is added to the neutral electrolyte, because a phase, active in discharge, is electrodeposited during charging. [ABSTRACT FROM AUTHOR]

This work consists of an experimental study on the ageing response and resulting properties of AA7050 plate material. New heat treatments are investigated for achieving a peak-aged temper, as a T6 temper may be said to be, that achieves yield and tensile strengths superior to those of the documented T7 treatments. For this alloy, the Standard establishes T7X tempers which were developed to obtain a very good compromise between mechanical strength and corrosion resistance. Nevertheless, for all those applications in which the environment is not considered critical for corrosion behaviour, the peak strength condition could be beneficial. In this experimental work, the authors use standard hardness testing to investigate mechanical response as a function of ageing time at several ageing temperatures, all applied immediately after solution. Upon identifying specific times and temperatures of interest, specimens aged under the selected treatments were subjected to tensile testing and intergranular corrosion testing. The results show that a single-step ageing heat treatment is able to produce a significantly high both yield and ultimate tensile strength. Moreover, the corrosion test data indicates that this new heat treatment produces corrosion resistance similar to that of the T76 heat treatment. [ABSTRACT FROM AUTHOR]

Keywords: batteries; mildly acidic; quaternary ammonium salts; X-ray microtomography; zinc EN batteries mildly acidic quaternary ammonium salts X-ray microtomography zinc 1 1 1 06/20/23 20230614 NES 230614 B The Cover Feature b shows a schematic representation of Zn plating from an aqueous electrolyte in the presence of Quaternary Ammonium Salts (QASs) (upper part) and in an additive-free solution (bottom element). The study provides insight into the cycling behavior of zinc anodes in battery context, using QASs as additives in mildly acidic aqueous electrolytes. [Extracted from the article]

Failure analysis normally requires many forms of investigation, but visual examination is the most used amongst all possible techniques. However, as the legal climate for fire investigation is becoming more rigorous, fire researchers need to work differently. In other words, to be technically defensible, expert testimony must be built on scientific data. To this aim, in-depth microstructural analyses of materials are particularly suitable to define the fire scene. This paper discusses some of the basic metallurgical theories used in failure analysis of copper, steel and aluminium alloy components involved in fire situations. Some components that can be easily found in fire and arson scene were submitted to simulated fire for indicated time and temperature. The collected samples were than examined by optical microscopy, scanning electron microscopy and energy-dispersive spectroscopy. Oxidation, recrystallization, second-phase precipitation and melting were some of the features observed on samples that can be strictly related to the thermal effect of fire. On the basis of these metallurgical results and starting from the evidence that different exposure temperatures can induce different metallurgical modifications, it is possible to define the temperature range experienced by various components, thus suggesting the fire dynamic during the incident. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Keywords: Cycling; Dendrite; Mathematical modelling; Passivation; Zinc EN Cycling Dendrite Mathematical modelling Passivation Zinc 1 1 1 05/17/22 20220513 NES 220513 B The Cover Feature b illustrates how the combination of electrochemical testing, mathematical modelling and X-ray micro-computed tomography enables the rational design of additives for dendrite-suppression in batteries with Zn anodes. Cover Feature: Insight into the Cycling Behaviour of Metal Anodes, Enabled by X-ray Tomography and Mathematical Modelling (ChemElectroChem 9/2022) Cycling, Dendrite, Mathematical modelling, Passivation, Zinc. [Extracted from the article]