Diffraction microstrain in nanocrystalline solids under load - heterogeneous medium approach

This is an account of the computation of X-ray microstrain in a polycrystal with anisotropic elasticity under uniaxial external load. The results have been published in the article "Microstrain in nanocrystalline solids under load by virtual diffraction", at Europhysics Letters 89, 66002 (2010). The present information was submitted to Europhysics Letters as part of the manuscript package, and was available to the reviewers who recommended the paper for publication.Comment: Supporting online material for J. Markmann, D. Bachurin, L.-H. Shao, P. Gumbsch, J. Weissm\"uller, Microstrain in nanocrystalline solids under load by virtual diffraction, Europhys. Lett. 89, 66002 (2010

On the impact of capillarity for strength at the nanoscale

The interior of nanoscale crystals experiences stress that compensates the capillary forces and that can be large, in the order of 1 GPa. Various studies have speculated on whether and how this surface-induced stress affects the stability and plasticity of small crystals. Yet, experiments have so far failed to discriminate between the surface contribution and other, bulk-related size effects. In order to clarify the issue, we study the variation of the flow stress of a nanomaterial while distinctly different variations of the two capillary parameters surface tension and surface stress are imposed under control of an applied electric potential. Our theory qualifies the suggested impact of $\textit{surface stress}$ as not forceful and instead predicts a significant contribution of the surface energy, as measured by the $\textit{surface tension}$. The predictions for the combined potential- and size dependence of the flow stress are quantitatively supported by the experiment. Previous suggestions, favoring the surface stress as the relevant capillary parameter, are not consistent with the experiment

Blame the Machine? Insights From an Experiment on Algorithm Aversion and Blame Avoidance in Computer-Aided Human Resource Management.

Algorithms have become increasingly relevant in supporting human resource (HR) management, but their application may entail psychological biases and unintended side effects on employee behavior. This study examines the effect of the type of HR decision (i.e., promoting or dismissing staff) on the likelihood of delegating these HR decisions to an algorithm-based decision support system. Based on prior research on algorithm aversion and blame avoidance, we conducted a quantitative online experiment using a 2×2 randomly controlled design with a sample of N = 288 highly educated young professionals and graduate students in Germany. This study partly replicates and substantially extends the methods and theoretical insights from a 2015 study by Dietvorst and colleagues. While we find that respondents exhibit a tendency of delegating presumably unpleasant HR tasks (i.e., dismissals) to the algorithm-rather than delegating promotions-this effect is highly conditional upon the opportunity to pretest the algorithm, as well as individuals' level of trust in machine-based and human forecast. Respondents' aversion to algorithms dominates blame avoidance by delegation. This study is the first to provide empirical evidence that the type of HR decision affects algorithm aversion only to a limited extent. Instead, it reveals the counterintuitive effect of algorithm pretesting and the relevance of confidence in forecast models in the context of algorithm-aided HRM, providing theoretical and practical insights

Anomalous compliance and early yielding of nanoporous gold

We present a study of the elastic and plastic behavior of nanoporous gold in compression, focusing on molecular dynamics simulation and inspecting experimental data for verification. Both approaches agree on an anomalously high elastic compliance in the early stages of deformation, along with a quasi immediate onset of plastic yielding even at the smallest load. Already before the first loading, the material undergoes spontaneous plastic deformation under the action of the capillary forces, requiring no external load. Plastic deformation under compressive load is accompanied by dislocation storage and dislocation interaction, along with strong strain hardening. Dislocation-starvation scenarios are not supported by our results. The stiffness increases during deformation, but never approaches the prediction by the relevant Gibson-Ashby scaling law. Microstructural disorder affects the plastic deformation behavior and surface excess elasticity might modify elastic response, yet we relate the anomalous compliance and the immediate yield onset to an atomistic origin: the large surface-induced prestress induces elastic shear that brings some regions in the material close to the shear instability of the generalized stacking fault energy curve. These regions are elastically highly compliant and plastically weak

Public Value at Cross Points: A Comparative Study on Employer Attractiveness of Public, Private, and Nonprofit Organizations

A commonly held assumption is that public service motivation (PSM) positively affects individuals’ attraction to government, but there are also private and nonprofit organizations that are beneficial to the common good. Therefore, the goal of this study is to shed light on an understudied topic in Public Administration, namely, how the public value of public, private, and nonprofit organizations affects their attractiveness to citizens and how PSM moderates this relationship. We find that employer attractiveness is strongly influenced by organizations’ public value regardless sectoral affiliation. This attribution of public value interacts with citizens’ PSM. For high-PSM individuals, the relationship between public value and attractiveness is stronger than for low-PSM individuals. Furthermore, high PSM exercises an asymmetric effect, punishing organizations with low public value more strongly in the private sector. These results highlight important implications for HR practitioners in all three sectors seeking to attract and retain highly motivated employees

Nanoporous-gold-based composites : toward tensile ductility

We report on mechanical tests on interpenetrating-phase nanocomposite materials made by vacuum impregnation of nanoscale metal networks with a polymer. The metal component is nanoporous gold made by dealloying, whereas two epoxy resins and polyurethane are explored as the polymer component. The composites are strong and deformable in compression. Although previous observations invariably indicate tensile brittleness for nanoporous gold, composite samples made from cm-sized nanoporous samples enable macroscopic tensile and four-point bending tests that show ductility. This implies that the high strength of individual metal objects such as nanowires can now be incorporated into a strong and ductile material from which macroscopic things can be formed. In fact, a rule-of-mixture-type analysis of the stresses carried by the metal phase suggests quantitative agreement with data reported from separate experiments on small-scale gold nanostructures