High strain rate superplasticity at intermediate temperatures of the Al 7075 alloy severely processed by equal channel angular pressing

The mechanical properties of an overaged Al 7075-O alloy processed by ECAP were examined by tensile tests at intermediate-high temperatures ranging from 250 to 400ºC and strain rates from 10−5 to 10−1 s−1. The influence of the number of ECAP passes on the ductility enhancement was evaluated. Elongation to failure, eF, significantly increased with increasing the number of ECAP passes up to 8 at 130ºC. The alloy processed under these conditions exhibited a maximum value of 322% at 300ºC and an initial strain rate of 10−3 s−1. High strain rate superplasticity was obtained at this temperature, eF=210%, at strain rate as high as 10−2 s−1. The large elongations together with lower stresses and lower stress exponents than those for the start material confirm that grain boundary sliding (GBS) is the operative deformation mechanism. A loss of superplastic behaviour at above temperatures of 350ºC is related to abnormal grain growth and a change of deformation mechanism.Financial support from MICINN (Project MAT2009-14452) is gratefully acknowledged.Peer reviewe

The molecular mechanism and physiological role of silent nociceptor activation

Silent nociceptors are sensory afferents that are insensitive to noxious mechanical stimuli under normal conditions but become sensitized to such stimuli during inflammation. Using RNA-sequencing and quantitative RT-PCR we demonstrate that inflammation selectively upregulates the expression of the transmembrane protein TMEM100 in silent nociceptors and electrophysiology revealed that over-expression of TMEM100 is required and sufficient to un-silence silent nociceptors. Moreover, we show that mice lacking TMEM100 do not develop secondary hyperalgesia, i.e. pain hypersensitivity that spreads beyond the site of inflammation, in a mouse model of knee joint inflammation and that AAV-mediated overexpression of TMEM100 in articular afferents in the absence of inflammation is sufficient to induce secondary hyperalgesia in remote skin regions without causing knee joint pain. Thus, our work identifies TMEM100 as a key regulator of silent nociceptor un-silencing and reveals a physiological role for this hitherto enigmatic afferent subclass in triggering spatially remote secondary hyperalgesia during inflammation

Evolution of Recrystallization Texture in AISI300 Series Austenitic Stainless Steels After Cold Rolling to Large Strain

The present paper deals with the evolution of texture in austenitic stainless steels during annealing after 95% cold rolling. After 95% cold rolling, the texture is mainly of the brass type {110} along with a scatter towards the S orientation {123} and Goss orientation {011} . Weak evidence of Cu component is observed at this high deformation level. During annealing, recovery is observed before any detectable recrystallization. After recrystallization, the overall texture intensity was weak; however, there are some discernible texture components. There was no existence of the brass component at this stage. Major components are centered on Goss orientation and Cu component {112} as well as the BR component {236} . Also, there are some few orientations which come up after recrystallization i.e. {142} and {012} . With increase in annealing temperature the textural evolution shows emergence of weak texture with another new component i.e. {197} . The evolution of texture was correlated with the deformation texture through twin chain reaction

Role of TMEM100 in mechanically insensitive nociceptor un-silencing

Mechanically silent nociceptors are sensory afferents that are insensitive to noxious mechanical stimuli under normal conditions but become sensitized to such stimuli during inflammation. Using RNA-sequencing and quantitative RT-PCR we demonstrate that inflammation upregulates the expression of the transmembrane protein TMEM100 in silent nociceptors and electrophysiology revealed that over-expression of TMEM100 is required and sufficient to un-silence silent nociceptors in mice. Moreover, we show that mice lacking TMEM100 do not develop secondary mechanical hypersensitivity—i.e., pain hypersensitivity that spreads beyond the site of inflammation—during knee joint inflammation and that AAV-mediated overexpression of TMEM100 in articular afferents in the absence of inflammation is sufficient to induce mechanical hypersensitivity in remote skin regions without causing knee joint pain. Thus, our work identifies TMEM100 as a key regulator of silent nociceptor un-silencing and reveals a physiological role for this hitherto enigmatic afferent subclass in triggering spatially remote secondary mechanical hypersensitivity during inflammation

An RCM Experimental and Modeling Study on CH4 and CH4/C2H6 Oxidation at Pressures up to 160 bar

The oxidation of CH4 and CH4/C2H6 mixtures were studied at pressures relevant to knocking in large bore natural gas engines. The experiments were carried out in a rapid compression machine (RCM) at end of compression (EOC) temperatures ranging between 885 and 940 K at compressed gas pressures of 105, 125, 150, and 160 bar at varying equivalence ratios (0.417, 0.526, and 1.0) and dilution percentages (0, 10, and 30% Exhaust Gas Recirculation - EGR) that were defined in a test matrix. This study describes the method and limitations of performing high-pressure experiments of this magnitude in an RCM, modeling, and validation of the kinetic mechanism against experimental data. While the recently published AramcoMech 2.0 could well predict the ignition delay times (IDTs) for CH4 within the uncertainty ranges at comparatively higher pressures and lower temperatures (885-940 K), the predicted reactivity is, in general, lower than that of AramcoMech 1.3 as shown in our previous screening study. Based on the comparison between both mechanisms as well as sensitivity analysis on the predicted IDTs, the reaction rate constant for (H) over dot-atom abstraction from CH4 by H(O) over dot(2) radical was optimized in order to achieve better agreement with the new data while maintaining the agreement to the previous data sets. The modified mechanism predicts well the IDTs and the trend of their variation caused by the change in pressure, equivalence ratio, dilution percentage, and mixture variation with C2H6. (C) 2017 Elsevier Ltd. All rights reserved.This research did not receive any specific grant from funding agencies in the public, commercial, or non-for-profit sectors.2019-06-1