Dielectric Properties of a Printed Sol–Gel Matrix Composite

Low temperature processable materials with high dielectric constants are required for application on flexible organic substrates, for example, in printed electronics. To date, mainly organic polymers with embedded functional particles have been investigated for this purpose. For the first time, we present a printable dielectric composite material composed of ferroelectric high permittivity particles (BaTiO₃) bonded by a mainly inorganic sol–gel derived network. The exemplary optimization of the properties by varying the sol–gel precursor illustrates the potential of sol–gel chemistry for printable functional materials. An operational gravure printed capacitor including printed silver electrodes is presented. The measured dielectric constants are among the highest reported in literature for low temperature cured films with moderate dissipation factors. Besides these promising dielectric properties, this composite film shows a ferroelectric response.     

The missing link in COS metabolism: a model study on the reactivation of carbonic anhydrase from its hydrosulfide analogue

Carbonic anhydrase (CA) is known to react with carbonyl sulfide, an atmospheric trace gas, whereby H(2)S is formed. It has been shown that, in the course of this reaction, the active catalyst, the His(3)ZnOH structural motif, is converted to its hydrosulfide form: His(3)ZnOH+COS-->His(3)ZnSH+CO(2). In this study, we elucidate the mechanism of reactivation of carbonic anhydrase (CA) from its hydrosulfide analogue by using density functional calculations, a model reaction and in vivo experimental investigation. The desulfuration occurs according to the overall equation His(3)ZnSH+H(2)O right harpoon over left harpoon His(3)ZnOH+H(2)S. The initial step is a protonation equilibrium at the zinc-bound hydrosulfide. The hydrogen sulfide ligand thus formed is then replaced by a water molecule, which is subsequently deprotonated to yield the reactivated catalytic centre of CA. Such a mechanism is thought to enable a plant cell to expel H(2)S or rapidly metabolise it to cysteine via the cysteine synthase complex. The proposed mechanism of desulfuration of the hydrosulfide analogue of CA can thus be regarded as the missing link between COS consumption of plants and their sulfur metabolism.     

Calculation of the VKI turbine blade with LES and DES

The prediction of the laminar to turbulent transition is essential in the calculation of turbine blades,compressorblades or airfoils of airplanes since a non negligible part of the flow field is laminar or transitional.In this paperwe compare the prediction capability of the Detached Eddy Simulation(DES)with the Large Eddy Simulation(LES)using the high-pass filtered(HPF)Smagorinsky model(Stolz et at.[1])when applied to the calculation oftransitional flows on turbine blades.Detailed measurements from Canepa et al.[2]of the well known VKI-turbineblade served to compare our results with the experiments.The calculations have been made on a fraction of theblade(10%)using non-reflective boundary conditions of Freund at the inlet and outer plane extended to internalflows by Magagnato et al.[3]in combination with the Synthetic Eddy Method(SEM)proposed by Jarrin et at.[4].The SEM has also been extended by Pritz et al.[5] for compressible flows.It has been repeatedly shown that hy-brid approaches can satisfactorily predict flows of engineering relevance.In this work we wanted to investigate ifthey can also be used successfully in this difficult test case.     

mr-NIL 6000LT – Epoxy-based curing resist for combined thermal and UV nanoimprint lithography below 50 °C

The aim of the work presented here was to develop curing polymers for nanoimprint lithography (NIL) enabling short cycle time, low imprint temperature, and an isothermal imprint process. The result is mr-NIL 6000LT: A photochemically curing polymer system for isothermal imprinting by combined thermal and UV nanoimprint lithography. It allows a lower imprint temperature than materials presented previously [C. Schuster, M. Kubenz, F. Reuther, M. Fink, G. Grützner, mr-NIL 6000 – New epoxy-based curing resist for efficient processing in combined thermal and UV nanoimprint lithography, in: Proceedings of SPIE 6517 2007, 65172B.; D.W. Johnson, H. Miller, M. Kubenz, F. Reuther, G. Grützner, Nanoimprinting with SU-8 Epoxy Resists, in: Proceedings of SPIE 6517 2007, 65172A.].The material system chosen is based on a blend of epoxy resins and a photo acid generator. Such epoxy resists cure during the imprint step in combined thermal and UV nanoimprint lithography. Initiated by UV exposure the cationic polymerisation occurs at elevated temperature forming a polymer pattern with significantly increased thermal stability compared to the uncured system.Apart from the material development leading to mr-NIL 6000LT the correlations between the parameters imprint temperature, exposure time and post exposure hold time are investigated in this work. With the applied resin combination a T_g of ?15 °C is obtained. This enables the formation of solid films at room temperature after spin-coating and prebake and nevertheless imprint temperatures in the range of 45–50 °C, which is a distinct decrease compared to the 100–110 °C needed for the previously introduced mr-NIL 6000 [C. Schuster, M. Kubenz, F. Reuther, M. Fink, G. Grützner, mr-NIL 6000 – New epoxy-based curing resist for efficient processing in combined thermal and UV nanoimprint lithography, in: Proceedings of SPIE 6517 2007, 65172B.] or the 65–70 °C necessary for defect-free imprinting of the epoxy-based polymer described in [D.W. Johnson, H. Miller, M. Kubenz, F. Reuther, G. Grützner, Nanoimprinting with SU-8 Epoxy Resists, in: Proceedings of SPIE 6517 2007, 65172A.]. mr-NIL 6000LT exhibits good dimensional stability at 120 °C after curing during the imprint process. This is sufficient for an isothermal imprint process as well as subsequent processes, e.g. metallization or etching.     

Report on the 10th International Conference on Autonomous Infrastructure,Management, and Security (AIMS 2016)

This article is a report of the IFIP AIMS 2016, which was held at Universität der Bundeswehr München, Germany from June 20 to June 23, 2016. AIMS 2016 focused on the theme “Management and Security in the Age of Hyperconnectivity”. The AIMS conference positions itself in the network management community as an educational venue for young researchers and Ph.D. students. The AIMS program included keynotes, technical sessions and Ph.D. Workshop sessions, but also hands-on labs and an educational panel for training young academics. The highlights on each of the parts of the AIMS 2016 program are summarized in this article.     

Noninterferometric topography measurements of fast moving surfaces

The topography of moving surfaces is recovered by noninterferometric measurements. The phase reconstruction is derived by measuring the intensities of a backscattered pulsed laser light and solving the transport intensity equation (TIE). The TIE is solved by expanding the phase into a series of Zernike polynomials, leading to a set of appropriate algebraic equations. This technique, which enables us to make a direct connection between experiments and the TIE, has been successfully tested in gas gun experiments. In particular, the topographies of a moving projectile and the free surface of a shocked target were recovered.     

Comparison of steroid hormone patterns in different fat tissues of Synovex-S implanted and control steers

Four different adipose tissues (kidney fat, heart fat, fat over rib, tailhead fat) of six control and seven Synovex-S (containing progesterone and 17#-estradiol benzoate)-implanted steers were investigated for their profiles of progesterone, androgens, and their precursors and metabolites. The steers were implanted with Synovex-S and slaughtered after 84 days. The tissues represent different bovine depot fats. Kidney and heart fat deposit at an earlier stage of development than the other subcutaneous fat tissues was investigated. Androgens, their precursors and progesterone were analysed by GC-MS. Estrogens could not be detected by GC-MS. Resulting hormone patterns were compared between treatments and between fat depots. The statistical Kruskal-Wallis-H-test was used for comparison. The adipose tissues showed similar hormone patterns. Only progesterone showed an increased concentration in adipose tissues of implanted steers. The steroid patterns did not show the influence of exogenous steroid administration.     

Flow Field and Performance of Cross Flow Fans——Experimental and Theoretical Investigations

Due to the construction and the operating principle the prediction of performance of Cross Flow Fans (CFF) is difficult and the knowledge about the internal flow regime is limited. To investigate the impact of geometrical parameters on the performance of CFF, experimental investigations, using Particle Imaging Velocimetry (PIV), and CFD calculations were carried out. Some results of PIV measurements and CFD calculations are presented, which give an impression of the internal flow and confirm the numerical calculations.     

Flow field and performance of Cross Flow Fans — Experimental and theoretical investigations

Due to the construction and the operaling principle the prediction of performance of Cross Flow Fans (CFF） is difficult and the knowledge about the internal flow regime is limited. To investigate the impact of geometrical parameters on the performance of CFF, experimental investigations, using Particle Imaging Velocimetry (PIV),and CFD calculations were carried out. Some results of PIV measurements and CFD calculations are presented,which give an impression of the internal flow and confirm the numerical calculations.     

Hydroxyl Content of BaTiO3 Nanoparticles with Varied Size

Different types of tetragonal BaTiO₃ particles were synthesized in a wet chemical process including an autoclave treatment. The synthesis and autoclaving medium was varied from isopropyl alcohol to water in different ratios, leading to a size variation of the particles from 38 to 145 nm. By applying combustion analysis of carbon and hydrogen (C/H analysis) released from the samples, it can be demonstrated that the amount of hydroxyl impurities incorporated into the crystal lattices of the particles increases with the water content of the synthesis medium. C/H analysis is a suitable tool for this characterization task as it allows discriminating different sources of these elements, i.e., different impurities. By comparing the self‐synthesized particles with commercial ones, it can be concluded that the particle size has the dominant influence on the tetragonality, if the amount of internal hydroxyl groups is relatively low. In contrast, if the amount of water originating from the internal OH groups is elevated (greater than ~0.4 wt%) an impairment of the tetragonality is caused.