Mechanical testing of twinned copper and copper alloy micropillars

Nanotwinned metals are a promising class of modern materials combining a very high strength and ductility with excellent electrical properties. Their remarkable strength is connected to the high effectiveness of twin boundaries as obstacles to dislocation motion. In order to further characterize these interactions, micropillars containing single coherent twin boundaries with different orientations were compressed with a flat punch and subsequently investigated in the scanning electron microscope. The crystal orientations for compression were selected to activate different slip modes. The aim is to probe the different barrier effects that can act on gliding dislocations. The investigations concentrated on copper and α-brass. The latter is a low stacking-fault energy alloy exhibiting a high density of recrystallization twins. Coherent twin boundaries were selected from an EBSD orientation mapping of the sample and oriented by means of a custom sample holder. FIB-milling at these interfaces yielded micropillar samples containing a single twin boundary. Single crystal reference samples were obtained from the bulk of the grain located on both sides of the twin boundary. The microcompression tests enabled the quantification of the influence of the twin boundary barrier on the strength of each sample. The tests evidenced a strong dependency of the strength of the sample on crystal orientation and stacking-fault energy. The activated glide systems were subsequently identified from slip trace analysis and STEM mapping of lamellas obtained by FIB lift-out from the bulk of the tested micropillars. Please click Additional Files below to see the full abstract

Optimized management of urolithiasis by coloured stent-stone contrast using dual-energy computed tomography (DECT)

Background We analysed in vitro the appearance of commonly used ureteral stents with dual-energy computed tomography (DECT) and we used these characteristics to optimize the differentiation between stents and adjacent stone. Methods We analysed in vitro a selection of 36 different stents from 7 manufacturers. They were placed in a self-build phantom model and measured using the SOMATOM® Force Dual Source CT-Scanner (Siemens, Forchheim, Germany). Each sample was scanned at various tube potentials of 80 and 150 peak kilovoltage (kVp), 90 and 150 kVp and 100 and 150 kVp. The syngo Post-Processing Suite software program (Siemens, Forchheim, Germany) was used for differentiation based on a 3–material decomposition algorithm (UA, calcium, urine) according to our standard stone protocol. Results Stents composed of polyurethane appeared blue and silicon-based stents were red on the image. The determined appearances were constant for various peak kilovoltage (kVp) values. The coloured stent-stone-contrast displayed on DECT improves monitoring, especially of small calculi adjacent to indwelling ureteral stents. Conclusion Both urinary calculi and ureteral stents can be accurately differentiated by a distinct appearance on DECT. For the management of urolithiasis patients can be monitored more easily and accurately using DECT if the stent shows a different colour than the adjacent stone

Sichere IT ohne Schwachstellen und Hintertüren

Unsere zunehmende Abhängigkeit von Informationstechnik erhöht kontinuierlich die Safety- und Security-Anforderungen bei deren Einsatz. Ein zentrales Problem hierbei sind Schwachstellen von Hard- und Software. Marktkräfte konnten diese Situation bislang nicht grundsätzlich beheben. Eine Gegenstrategie sollte deshalb folgende Optionen erwägen: (1) private und staatliche Förderung offener und sicherer IT‑Produktion, (2) Verbesserung der souveränen Kontrolle bei der Produktion aller kritischen IT‑Komponenten innerhalb eines Wirtschaftsraumes sowie (3) verbesserte und durchgesetzte Regulierung. Dieser Beitrag analysiert Vor- und Nachteile dieser Optionen. Es wird vorgeschlagen, die Sicherheit der Schlüsselkomponenten einer Lieferkette durch weltweit verteilte, offene und ggf. mathematisch bewiesene Komponenten zu gewährleisten. Der beschriebene Ansatz erlaubt die Nutzung existierender und neuer proprietärer Komponenten

Ten millennia of hepatitis B virus evolution

Hepatitis B virus (HBV) has been infecting humans for millennia and remains a global health problem, but its past diversity and dispersal routes are largely unknown. We generated HBV genomic data from 137 Eurasians and Native Americans dated between ~10,500 and ~400 years ago. We date the most recent common ancestor of all HBV lineages to between ~20,000 and 12,000 years ago, with the virus present in European and South American hunter-gatherers during the early Holocene. After the European Neolithic transition, Mesolithic HBV strains were replaced by a lineage likely disseminated by early farmers that prevailed throughout western Eurasia for ~4000 years, declining around the end of the 2nd millennium BCE. The only remnant of this prehistoric HBV diversity is the rare genotype G, which appears to have reemerged during the HIV pandemic

De Rebus Merae Facultatis : Dissertatio Juridica

Quam In inclyta Argentoratensium Academia, Praeside ... Dn. Friderico Deckherro ... Solenni disquisitioni die 14. Junii, instituendae offert, Joh. Philippus Krauß, E Suevis Ravenspurgensi

Towards Fast Morphological Mosaicking of High-Resolution Multi-Spectral Products – On Improvements of Seamlines

The complex process of fully automatically establishing seamlines for the fast production of high-quality mosaics with high-amount of high-resolution multi-spectral images is detailed and improved in this paper. The algorithm is analyzed and a quasi-linear runtime in the number of considered pixels is proven for all situations. For typical situations the storage is even essentially smaller from a complexity theoretical perspective. Improvements from algorithm practical perspective are specified, too. The influence of different methods for the determination of seamlines based on gradients is investigated in detail for three Sentinel-2 products. The studied techniques cover well-known ones normally based on a single band. But also more sophisticated techniques based on multiple bands or even taking additional external geo-information data are taken into account. Based on the results a larger area covered by Image2006 orthorectified products with data of the Resourcesat-1 mission is regarded. The feasibility of applying advanced subordinated methods for improving the mosaic such as radiometric harmonization is examined. This also illustrates the robustness of the improved seamline determination approaches

VibTacX: A taxonomy for vibro-tactile patterns

In human-computer interaction, the tactile sense can be used as an intuitive and immediate interface for users. Within the context of various research projects, numerous vibro-tactile patterns (tactons) have been presented and discussed. However, comparing them is difficult due to the lack of a common classification. In this paper, we present and discuss our taxonomy called VibTacX. We illustrate this taxonomy using two exemplary tactons. Finally, we discuss existing challenges and future research directions

Phase-type fitting using hyperstar

In this paper we provide a hands-on discussion of the use of the HyperStar phase-type fitting tool in common application scenarios. HyperStar allows fitting Hyper-Erlang distributions to empirical data, using a variety of algorithms and operation modes. We describe simple cluster-based fitting, a new graphical method for refining the density approximation, a new command-line interface, and the integration of HyperStar with a Mathematica implementation of a fitting algorithm. Furthermore, we describe the use of Hyper-Erlang distributions in simulation. Throughout our discussion we illustrate the concepts on a data set which has been shown to be difficult to fit with a PH distribution