Surface- and volume-based investigation on influences of different Varestraint testing parameters and chemical compositions on solidification cracking in LTT filler metals

The subject of this study is how, and to what extent, Varestraint/Transvarestraint test results are influenced by both testing parameters and characteristics of evaluation methods. Several different high-alloyed martensitic LTT (low transformation temperature) filler materials, CrNi and CrMn type, were selected for examination due to their rather distinctive solidification cracking behaviour, which aroused interest after previous studies. First, the effects of different process parameter sets on the solidification cracking response were measured using standard approaches. Subsequently, microfocus X-ray computer tomography (μCT) scans were performed on the specimens. The results consistently show sub-surface cracking to significant yet varying extents. Different primary solidification types were found using wavelength dispersive X-ray (WDX) analysis conducted on filler metals with varying Cr/Ni equivalent ratios. This aspect is regarded as the main difference between the CrNiand CrMn-type materials in matters of cracking characteristics. Results show that when it comes to testing of modern highperformance alloys, one set of standard Varestraint testing parameters might not be equally suitable for all materials. Also, to properly accommodate different solidification types, sub-surface cracking has to be taken into account

Insights into receptor structure and dynamics at the surface of living cells

Evaluating protein structures in living cells remains a challenge. Here, we investigate Interleukin-4 receptor alpha (IL-4Rα) into which the non-canonical amino acid bicyclo[6.1.0]nonyne-lysine (BCNK) is incorporated by genetic code expansion. Bioorthogonal click labeling is performed with tetrazine-conjugated dyes. To quantify the reaction yield in situ, we develop brightness-calibrated ratiometric imaging, a protocol where fluorescent signals in confocal multi-color images are ascribed to local concentrations. Screening receptor mutants bearing BCNK in the extracellular domain uncovered site-specific variations of both click efficiency and Interleukin-4 binding affinity, indicating subtle well-defined structural perturbations. Molecular dynamics and continuum electrostatics calculations suggest solvent polarization to determine site-specific variations of BCNK reactivity. Strikingly, signatures of differential click efficiency, measured for IL-4Rα in ligand-bound and free form, mirror sub-angstrom deformations of the protein backbone at corresponding locations. Thus, click efficiency by itself represents a remarkably informative readout linked to protein structure and dynamics in the native plasma membrane

Design and investigation of a test rig based on AI smart vi-sion sensors for automated component inspection of press-hardened car body components

Defects such as cracks, overlaps and impressions occur during the production of press-hardened car body components. At present, these types of defects are counteracted in the industrial environment by costly visual inspections carried out by humans. Due to the poor efficiency of visual inspection compared to automated inspection and the risk of defects not being detected, the use of AI-based smart vision sensors is being evaluated in order to enable an automated component inspection process with their help. For the realisation of the test, the most relevant defect types deformation, crack and overlap are identified using a Pareto analysis

Optical Properties of the Kara Sea

This study was motivated by the need to understand dispersion processes which affect the redistribution of nuclear wastes in the Arctic from dump sites in the Kara Sea and in the rivers which flow into the Kara Sea. We focus on vertical profiles of light beam transmission and fluorometry made over the delta region fronting the Ob and Yenisey Rivers and over the East Novaya Zemlya Trough (ENZT). The delta region fronting the Ob River Estuary contains a large repository of particles in a dense bottom nepheloid layer with a maximum centered similar to 100 km in front of the estuary entrance and covering an area of roughly 200 km diameter. This suspended particle mass repository appears to contain both sediments and detritus and lends credence to the Lisitsyn [1995] concept of the marginal filter zone. In the deep water of the ENZT we found a strong increase of beam attenuation with depth, indicating a relatively large increase of particle mass concentration from similar to 50 m to the bottom (depths in excess of 300 m). The strongest concentration was adjacent to the southeast coast of Novaya Zemlya. We suggest that a type of hyperpycnical flow occurs from accumulation of sediments in the bottom waters of Novaya Zemlya fjords which then cascades down the steep slopes adjacent to the island, producing the particle mass distribution as observed by the transmissometer. The accumulation of these repositories of high particle mass concentrations in suspension would suggest that the residence time is high but that storm-driven events could act to disperse the material

Discovery of magnetic fields in central stars of planetary nebulae

For the first time we have directly detected magnetic fields in central stars of planetary nebulae by means of spectro-polarimetry with FORS1 at the VLT. In all four objects of our sample we found kilogauss magnetic fields, in NGC1360 and LSS1362 with very high significance, while in EGB5 and Abell36 the existence of a magnetic field is probable but with less certainty. This discovery supports the hypothesis that the non-spherical symmetry of most planetary nebulae is caused by magnetic fields in AGB stars. Our high discovery rate demands mechanisms to prevent full conservation of magnetic flux during the transition to white dwarfs.Comment: 8 pages, 4 figures, Accepted for Publication by Astronomy & Astrophysics See also press release by A&A on their homepage www.edpsiences.or

In vivo characterization of protein-protein interactions in the AP1 system with fluorescence correlation spectroscopy (FCS).

The aim of these studies is the quantitative investigation of protein-protein interactions in the AP1 system in vivo. First results of FCS measurements show an exchange in the nucleus of the proteins Fos-CFP and Jun-YFP in the stably mono-transfected HeLa-Cells. This is also shown by fitting the bleaching curves measured in the nucleus with an appropriate model. We obtained dissociation times between 10 and 20 seconds in the nucleus. In the autocorrelation function a free and an obstructed component of diffusion are shown. For further studies doubly transfected cells with both proteins, Fos-CFP and Jun-YFP, were prepared. These cells will now be characterized with FCCS to investigate the protein-protein interactions. In order to obtain the dissociation rates of the complex in the cell nucleus bleaching curves will be recorded on these cell lines. We also overexpressed and purified Jun-YFP and Fos-CFP for in vitro studies

Konzeption und Untersuchung eines Prüfstandes auf der Basis von KI-Smart-Vision-Sensoren für die automatisierte Bauteilprüfung pressgehärteter Karosseriebauteile

Bei der Herstellung pressgehärteter Karosseriebauteile treten Fehler wie Risse, Überlappungen und Abdrücke auf. Gegenwärtig wird diesen Fehlerarten im industriellen Umfeld durch kostenaufwändige, von Menschen durchgeführte Sichtkontrollen entgegengewirkt. Aufgrund des schlechten Wirkungsgrades der visuellen Prüfung gegenüber einer automatisierten Prüfung und der Gefahr des Nichterkennens von Fehlern, wird der Einsatz von KI-basierten Smart-Vision-Sensoren evaluiert, um mit deren Hilfe einen automatisierten Bauteilprüfprozess zu ermöglichen

Single Bead Labeling Method for Combining Confocal Fluorescence On-Bead Screening and Solution Validation of Tagged One-Bead One-Compound Libraries

SummaryScreening of one-bead one-compound libraries by incubating beads with fluorescently labeled target protein requires isolation and structure elucidation of a large number of primary hit beads. However, the potency of the identified ligands is only revealed after time consuming and expensive larger scale resynthesis and testing in solution. Often, many of the resynthesized compounds turn out to be weak target binders in solution due to large differences between surface and solution binding affinities. For an industry style high-throughput screening (HTS) process a high false positive rate is detrimental. We have therefore combined single bead and single molecule/single cell techniques into an integrated HTS process in which the picomole amount of substance contained on one isolated hit bead is sufficient for quality control, structure determination, and precise affinity determination to the target protein in solution

Influence on the bead geometry in Laser Metal Deposition with wire

peer reviewedLaser metal deposition with wire (LMD-w) is a promising additive manufacturing technology, which attracts interest due to the low waste of material, the flexible application possibilities along the production chain and the improved metallurgical properties compared to powder-based processes. However, the complex handling of the technology and the resulting low process stability inhibit the broad industrial application. In particular, the varying bead geometry prevents automation and series production. To improve the geometric accuracy, it is necessary to understand influencing parameters. For this purpose, a parameter study is carried out in the present work. Different combinations of laser power, wire feed rate, traverse speed and welding angle are set, and the deposited beads are evaluated in terms of height and width. A factorial design experiment with the Box-Behnken was used to analyse and understand the interaction of these parameters on the deposited beads