Ein Modell für verantwortungsvolles Handeln in der IT-Organisation

In der Betriebswirtschaft ist verantwortungsvolles Handeln, repräsentiert durch Konzepte wie Corporate Social Responsibility (CSR), Corporate Citizenship (CC) oder Nachhaltigkeit/Sustainability, eine in Forschung und Praxis breit diskutierte Thematik. Eine umfassende Übertragung der Problematik auf das IT-Management hat jenseits von isolierten Einzelthemen wie „Green IT“ etc. jedoch noch nicht stattgefunden. In diesem Beitrag wird deshalb ein Modell vorgestellt, welches auf der einen Seite einen ganzheitlichen Rahmen für verantwortungsvolles Handeln in der IT-Organisation eröffnet, und auf der anderen Seite Stellschrauben für die aktive, verantwortungsvolle Beeinflussung des Wettbewerbsumfelds aufzeigt. Konkretisiert wird das aufgezeigte Modell anhand verschiedener Maßnahmenfelder zur Umsetzung verantwortungsvollen Handelns

Constrained Multiobjective Biogeography Optimization Algorithm

Multiobjective optimization involves minimizing or maximizing multiple objective functions subject to a set of constraints. In this study, a novel constrained multiobjective biogeography optimization algorithm (CMBOA) is proposed. It is the first biogeography optimization algorithm for constrained multiobjective optimization. In CMBOA, a disturbance migration operator is designed to generate diverse feasible individuals in order to promote the diversity of individuals on Pareto front. Infeasible individuals nearby feasible region are evolved to feasibility by recombining with their nearest nondominated feasible individuals. The convergence of CMBOA is proved by using probability theory. The performance of CMBOA is evaluated on a set of 6 benchmark problems and experimental results show that the CMBOA performs better than or similar to the classical NSGA-II and IS-MOEA

Genomic monitoring of SARS-CoV-2 uncovers an Nsp1 deletion variant that modulates type I interferon response

The SARS-CoV-2 virus, the causative agent of COVID-19, is undergoing constant mutation. Here, we utilized an integrative approach combining epidemiology, virus genome sequencing, clinical phenotyping, and experimental validation to locate mutations of clinical importance. We identified 35 recurrent variants, some of which are associated with clinical phenotypes related to severity. One variant, containing a deletion in the Nsp1-coding region (D500-532), was found in more than 20% of our sequenced samples and associates with higher RT-PCR cycle thresholds and lower serum IFN-beta levels of infected patients. Deletion variants in this locus were found in 37 countries worldwide, and viruses isolated from clinical samples or engineered by reverse genetics with related deletions in Nsp1 also induce lower IFN-beta responses in infected Calu-3 cells. Taken together, our virologic surveillance characterizes recurrent genetic diversity and identified mutations in Nsp1 of biological and clinical importance, which collectively may aid molecular diagnostics and drug design.Peer reviewe

CPFEM investigation of effects of residual stress and work hardening on the tensile behavior of a shot peened steel

International audienceIt is generally accepted that shot peening can improve the fatigue resistance of materials. Therefore this technique and its variants are largely used in industry to strengthen critical mechanical components. This increase of material performance is thought to be mainly due to the superficial compressive residual stress and the work hardening generated during these treatments. Globally a rather good understanding of their roles in improving the material performance has been obtained. However, the majority of the studies do not take into account the fact that the residual stress and the work hardening generated by shot peening are of multiaxial nature. In this work, the effect of work hardening and compressive residual stress induced by shot peening on the tensile behavior of a stainless steel is studied using crystal plasticity finite element method (CPFEM). A phenomenological crystal plasticity model is used on a polycrystal representative elementary volume (REV) to investigate plastic activities at the slip system level under different loading conditions. Results show that the work hardening and the residual stress of different directions play different roles in determining the mechanical behavior of shot peened steel under uniaxial tensile loading. The results of numerical simulations are compared to the experimental results of tensile tests, and interpretations are given based on the plastic slip activities under different loading conditions

Peening-induced work hardening gradient and prediction of residual stress for a shot peened structure

International audienc

Low cycle fatigue properties of an austenitic stainless steel 316L processed by surface mechanical attrition treatment

International audienceEffect of surface mechanical attrition treatment (SMAT) on low cycle fatigue properties of an austenitic stainless steel 316L is studied using cyclic push-pull loading tests, with total strain amplitudes of ±0.5%, ±0.8%, and ±1.25%, respectively. Based on Electron Backscatter Diffraction (EBSD) observation and microhardness test, nanocrystalline layer, mixed grain size layer, and work hardened layer were generated near the treated surface by SMAT. During cyclic loading, SMAT-processed material exhibits higher cyclic stress amplitude due to the higher strength of SMAT affected region. Scanning Electron Microscopy (SEM) observation of fatigue fracture indicates that fatigue crack initiation occurs likely on external surface of SMAT-processed material, and propagated inward in transgranular mode with the formation of fatigue striations. Furthermore, fatigue lifetime of material under high strain amplitude (±1.25%) decreases due to SMAT. Fatigue Life analysis using Coffin-Manson law and energy dissipation theory indicates that this lifetime decrease is considered to be due to the diminution of ductility and fatigue damage capacity, along with higher energy dissipation rate in the SMAT affected region

Effect of surface mechanical attrition treatment on low cycle fatigue properties of an austenitic stainless steel

International audienceIn order to study the influence of surface mechanical attrition treatment (SMAT) on low cycle fatigue (LCF) properties of an austenitic stainless steel AISI 316L, cyclic loading responses and fatigue lifetime are investigated using fully reversed tension-compression LCF tests under total strain control. The results reveal that SMATed material exhibits higher cyclic stress amplitude due to higher strength of the SMAT affected region. During cyclic loading, untreated material is hardened under high strain amplitude (±0.8%, ±1.25%), but softened under low strain amplitude (±0.5%). In contrast, SMAT affected region undergoes cyclic softening. Furthermore, SMAT mainly affects cyclic behavior of the early stage of LCF, and its effect is gradually reduced as cyclic loading goes on. Fatigue lifetime analysis indicates that SMAT could decrease the fatigue lifetime of material under cyclic loading with high strain amplitude (±1.25%). Based on analysis using Coffin-Manson law and energy dissipation theory, this lifetime decrease is considered to be due to the decrease of ductility and fatigue damage capacity

Cyclic behavior of gradient microstructure generated by Surface Mechanical Attrition Treatment for an austenitic stainless steel

International audienceLow cycle fatigue (LCF) behavior of materials processed by SMAT (Surface Mechanical Attrition Treatment) was studied for a stainless steel 316L. SMAT was used to generate gradient microstructure in cylindrical fatigue specimens. Fully reversed strain controlled LCF tests were performed with different strain amplitudes. Hysteresis loops corresponding to different depths from the treated surface were indirectly obtained from the loops obtained by the fatigue tests for SMAT treated and untreated specimens. The results show that the influence of SMAT on cyclic behavior of material is effective mainly during the first several cycles, and it is gradually reduced with the increase of number of cycles. The results also show that SMAT causes the decrease of life in the case where the imposed strain amplitude is high. According to the analysis based on energy dissipation theory, this fatigue life decrease of the SMAT processed specimens could be due to the higher energy dissipation rate in the SMAT affected region

Cyclic plasticity modelling of austenitic steels with complex behavior

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