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The mechanical properties of metallic glasses are often tuned by annealing, which influences these properties by adjusting the relaxation and/or crystallization status of the glasses. Here, we studied the hardness and modulus of Pt57.5Cu14.7Ni5.3P22.5 bulk metallic glass annealed at different temperatures by nanoindentation, where the annealing gives the material different fictive temperatures and fractions of crystallization. It is found that both reducing the fictive temperature of a fully amorphous sample and increasing the degree of crystallization in a partially crystallized sample increase hardness and modulus. Combining the two approaches, elevated hardness and modulus values are found for composite materials containing both crystalline and amorphous phases when they are compared to chemically identical alloys featuring similar percentages of crystalline and amorphous phases that have been prepared by annealing at higher temperatures. Our findings indicate that the mechanical properties of the platinum-based alloys can be customized by processing them with targeted heat treatments.
Dispositionalists maintain that the essence of a property is determined by the powers it confers upon its bearers and, as a result, that there is a necessary connection between properties and their powers. Contingentists, in contrast, maintain that the connection is contingent. The ability to conceive of a property as failing to confer some of its powers is often cited as an objection against dispositionalism. The standard dispositionalist response to this objection is to redescribe the imagined scenario so that it no longer serves as a threat. Using the literature on phenomenal concepts as inspiration, I develop a new defense of dispositionalism that echoes Brian Loar's (1990) response to conceivability arguments against physicalism. Not only can Loar's general strategy be usefully applied to this new context, there is a sense in which that strategy works better here than it does in the original context in which Loar deployed it.
Specifically designed microlattices are able to combine outstanding mechanical and physical properties and, thus, expand the actual limits of the material property space. However, post-yield softening induced by plastic buckling or crushing of individual ligaments limits performance under cyclic loading, which affects their energy absorption capabilities. Understanding deformation under repeated loading is key to further optimizing these high-strength materials. While until now mainly hollow metallic microlattices and multistable or tailored buckling structures have been analyzed, this study investigates deformation and failure of polymer and ceramic-polymer microlattices under cyclic loading to understand the (i) influence of the microarchitecture and (ii) influence of processing conditions on the energy absorption capability. Despite fracture of individual struts, the stretching-dominated microarchitectures possess a superior behavior especially for larger cycle numbers. In combination with a specific annealing treatment of the polymer material, high recoverability and energy dissipation can be achieved.
Active participation in social activities is important for the wellbeing of older adults. This study explored benefits of active social engagement by evaluating whether relationships that comprise active involvement (e.g. co-engagement in activities) bring more social benefits (i.e. social support, companionship, positive social influence) than other relationships that do not involve co-engagement. A total of 133 adults ages 60 years and older living in a rural Midwestern city in the United States of America were interviewed once and provided information on 1,740 social network members. Among 1,506 social relationships in which interactions occurred at least once a month, 52 per cent involved engagement in social activities together and 35 per cent involved eating together regularly. Results of the generalised linear mixed model showed that relationships involving co-engagement were significantly more likely to also convey social support (i.e. emotional, instrumental, informational), companionship and social influence (encouragement for healthy behaviours) than relationships that do not involve co-engagement. Having more network members who provide companionship was associated with higher sense of environmental mastery, positive relations with others and satisfaction with social network. Interventions may focus on maintaining and developing such social relationships and ensuring the presence of social settings in which co-engagement can occur. Future research may explore whether increasing co-engagement leads to an enhanced sense of companionship and psychological wellbeing.
When using bifunctional core@shell catalysts, the stability of both the shell and core–shell interface is crucial for catalytic applications. In the present study, we elucidate the stability of a CuO/ZnO/Al2O3@ZSM-5 core@shell material, used for one-stage synthesis of dimethyl ether from synthesis gas. The catalyst stability was studied in a hierarchical manner by complementary environmental transmission electron microscopy (ETEM), scanning electron microscopy (SEM) and in situ hard X-ray ptychography with a specially designed in situ cell. Both reductive activation and reoxidation were applied. The core–shell interface was found to be stable during reducing and oxidizing treatment at 250°C as observed by ETEM and in situ X-ray ptychography, although strong changes occurred in the core on a 10 nm scale due to the reduction of copper oxide to metallic copper particles. At 350°C, in situ X-ray ptychography indicated the occurrence of structural changes also on the µm scale, i.e. the core material and parts of the shell undergo restructuring. Nevertheless, the crucial core–shell interface required for full bifunctionality appeared to remain stable. This study demonstrates the potential of these correlative in situ microscopy techniques for hierarchically designed catalysts.
A new closed cell is presented for in situ X-ray ptychography which allows studies under gas flow and at elevated temperature. In order to gain complementary information by transmission and scanning electron microscopy, the cell makes use of a Protochips E-chipTM which contains a small, thin electron transparent window and allows heating. Two gold-based systems, 50 nm gold particles and nanoporous gold as a relevant catalyst sample, were used for studying the feasibility of the cell. Measurements showing a resolution around 40 nm have been achieved under a flow of synthetic air and during heating up to temperatures of 933 K. An elevated temperature exhibited little influence on image quality and resolution. With this study, the potential of in situ hard X-ray ptychography for investigating annealing processes of real catalyst samples is demonstrated. Furthermore, the possibility to use the same sample holder for ex situ electron microscopy before and after the in situ study underlines the unique possibilities available with this combination of electron microscopy and X-ray microscopy on the same sample.
1 spoken or written words that have no meaning or make no sense: he was talking absolute nonsense.
• [as exclamation] used to show strong disagreement: ‘Nonsense! No one can do that.’
• [as modifier] denoting verse or other writing intended to be amusing by virtue of its absurd or whimsical language: nonsense poetry.
2 foolish or unacceptable behavior: put a stop to that nonsense, will you?
Outrage arose when Representative Todd Akin of Missouri argued against making exceptions to the abortion restriction for rape victims on the grounds that due to a woman's physiology ‘legitimate rape’ was unlikely to result in pregnancy. Although thoroughly denounced, the claim that there is some feature of biology that prevents rapes from resulting in pregnancy has taken root in the political and popular imagination. This falsehood has proven so irrepressible that one reporter at Slate.com has written repeatedly about the ultimate source of this idea: a confabulated Nazi experiment. Discourse with these features– a ‘strange’ genealogy; bad reasoning; persistence despite, at best, specious proof; and exploitation for what are, to some minds, malicious purposes – has become increasingly common in political discourse, the press and even the arguments made by ordinary folk.
Such discourse is oft en criticized for its falsehood or its hurtfulness; these critiques – aimed at singular features of this discourse – tend to miss its pernicious potential.