Analysis of stable crack propagation in filled rubber based on a global energy balance

Stable crack propagation in filled rubber is investigated by means of experimental and finite element analyses. Based on an experimental evaluation of multiple specimens under different loading states, dissipation rates are computed by applying a global energy balance. The dissipation rates calculated analogously from results of a numerical simulation of the multiple specimen method are in good accordance with the experimental findings. A further comparison of simulation results evaluated on basis of the material force method with energy release rates computed by means of an energy balance of two crack states under fixed loading conditions shows that the measured fracture sensitivity values are mainly related to the development and increase of a dissipative zone.     

Evaluation of bioinspired functional surfaces for nanoparticle filtering

We present the development of a novel integrated device for airborne nanoparticle filtering with bioinspired nanoscale functionality. The underlying idea is to investigate the principle of adherent surfaces, e.g. pollen, as a biological model and transfer this functionality into a technology using functionalized microstructured surfaces. This might offer an efficient filtering method for nanoscale airborne particles without the limitations in gas permeability of conventional filters. We investigated the different pollen species for their structural and biochemical surface properties to achieve bioinspired surface functionality on silicon surfaces. The resulting conical structures have sizes from 4 to 20 μm. Depending on structure sizes, the adhesive properties of the surfaces towards aerosol particles could be directly influenced. The surfaces were tested in a demonstrator setup and the collection efficiency visually determined.     

A forming process for the increase of α′-martensite growth-rate under mechanical load

At the Institute of Metal Forming and Metal-Forming Machines (IFUM), metastable austenitic sheet metal components are examined concerning the use of their base materials as sensors. By measuring the martensite content at sensitized reference points of these components, it is possible to draw conclusions about their load history. The local sensitizations are done by defined elongations and residual stresses using a forming process. This results in a component-inherent sensor acting as a damage control element, e.g. by registering and storing strains during the component’s life cycle.     

Penetrationstests als Instrument zur Qualitätssicherung

Zusammenfassung  Für Unternehmen, deren Gesch?ftsprozesse unmittelbar von der Verfügbarkeit, Integrit?t und Vertraulichkeit ihrer IT-Infrastruktur abh?ngen, stellen Penetrationstests ein wesentliches Element einer zukunftsorientierten IT-Sicherheitsplanung dar. Richtig angewandt, sorgen sie mittel- und langfristig für eine Effizienzsteigerung bei Investitionen sowie ein allgemein hohes Sicherheitsniveau, wie es die Regelungen des KonTraG und des Sarbanes-Oxley Acts oder das internationale Bankenabkommen Basel II vorgeben. Diplom-Informatiker und geh?rt als Gesch?ftsführer der SySS GmbH seit 2005 zum Herausgeberbeirat von IT-Sicherheit & Datenschutz Diplom-Wirtschaftsinformatikerin und als Security Consultant für die SySS GmbH t?tig     

The formation of two Ag UPD layers on stepped Pt single crystal electrodes and their restructuring by co-adsorption of CO

We have investigated the underpotential deposition (UPD) of silver on high-index platinum single crystals vicinal to the (1 1 1) plane. Carbon monoxide displacement experiments were carried out on Ag-modified Pt(6 6 5) and Pt(3 3 2) stepped single crystal electrodes and examined by means of electrochemical scanning tunneling microscopy (EC-STM) and cyclic voltammetry (CV) in 0.05 M sulfuric acid. Analogous to studies of Pt(1 1 1) by Klein [L.H. Klein, Etude des etats d’adsorption electrochimique sur les electrodes de platine et de rhodium monocristallins modifiees ou non par les adatomes, Ecole Nationale de Chimie de Paris, Universite Paris 6, Paris, 1997] and Domke et al. [K.F. Domke, X.-Y. Xiao, H. Baltruschat, PCCP 10 (2008) 1555], carbon monoxide displaces Ag from stepped Pt electrodes. The present STM studies reveal the formation of small, biatomic thick or thicker Ag clusters on Pt(6 6 5) and Pt(3 3 2) after co-adsorption of CO, extending across step edges, They have a narrow size distribution centred around 10 nm diameter independent of the substrate step density. The desorption of the second Ag adlayer and of CO are monitored electrochemically in two well-separated oxidation peaks at around 0.68 and 0.9 V vs RHE, respectively, whereas the desorption peak of Ag of the first adlayer cannot be completely separated from the early onset of Pt oxidation at approximately 1.13 V vs RHE.     

Fragment‐Based Lead Discovery: Screening and Optimizing Fragments for Thermolysin Inhibition

Fragment‐based drug discovery has gained a foothold in today's lead identification processes. We present the application of in silico fragment‐based screening for the discovery of novel lead compounds for the metalloendoproteinase thermolysin. We have chosen thermolysin to validate our screening approach as it is a well‐studied enzyme and serves as a model system for other proteases. A protein‐targeted virtual library was designed and screening was carried out using the program AutoDock. Two fragment hits could be identified. For one of them, the crystal structure in complex with thermolysin is presented. This compound was selected for structure‐based optimization of binding affinity and improvement of ligand efficiency, while concomitantly keeping the fragment‐like properties of the initial hit. Redesigning the zinc coordination group revealed a novel class of fragments possessing K_i values as low as 128 μM , thus they provide a good starting point for further hit evolution in a tailored lead design.     

CLA TAG rich in cis‐9,trans‐11‐CLA is stable beyond 2 years of proper storage

We analyzed a triacylgylcerol esterified CLA preparation characteristically rich in c9,t11‐CLA and free of t10,c12‐CLA three times within a period of 2${1 \over 2}$ years by GC and silver ion‐HPLC. For the first time, we present data on the long‐term stability of this preparation with regard to the fatty acid profile and the isomeric composition of CLA under certain storage conditions, providing useful information for the planning of long‐term trials.