Detection of Cavitation Phenomena in Reciprocating Pumps using a High‐Speed Camera

Cavitation in reciprocating positive displacement pumps is still an insufficiently understood problem. For a better understanding of the effects of cavitation in reciprocating positive displacement pumps, high‐speed camera measurements were done under real operating conditions. In this work, emphasis is put on the recording of cavitation phenomena for further investigations. Exemplarily, the occurring cavitation phenomena for different valve designs are described on the basis of high‐speed sequences for selected cavitation conditions and the results are discussed.     

Regioselective Biocatalytic Transformations Employing Transaminases and Tyrosine Phenol Lyases

Topics in Catalysis - Regioselective reactions allow the differentiation between two or more chemically identical reactive centers within the same molecule. They are highly desirable...     

Ultra-high field MRI for primate imaging using the travelling-wave concept

Object

Ultra-high field (UHF) neuroimaging is usually conducted with volume transmit (Tx) and phased array receive (Rx) coils, both tightly enclosing the object. The travelling-wave (TW) concept allows a remote excitation offering more flexible experimental setups. To investigate the feasibility of primate MRI in horizontal UHF MRI, we first compared the distribution of the electromagnetic fields in an oil phantom and then verified the concept with an in vivo experiment.

Materials and methods

In the phantom experiments an in-house circularly polarized hybrid birdcage coil and a self-developed patch antenna were used for Tx and an eight-element phased array antenna for Rx. B ₁ ⁺ fields were calculated and measured for both approaches. For in vivo experiments the Rx part was replaced with an optimized three-element phased array head coil. The SAR was calculated using field simulation.

Results

In the phantom the field distribution was homogenous in a central volume of interest of about 10 cm diameter. The TW concept showed a slightly better homogeneity. Examination of a female crab-eating macaque led to homogeneous high-contrast images with a good delineation of anatomical details.

Conclusion

The TW concept opens up a new approach for MRI of medium-sized animals in horizontal UHF scanners.     

Datenschutzrechtliche Aspekte bei der weitergabe von IP-Adressen

Im Alltag eines Administrators werden rund um den Betrieb von Web- und E-Mail-Servern in vielerlei Hinsicht IP-Adressen gespeichert oder sogar an Dritte übermittelt. H?ufig übersehen oder gar wissentlich übergangen wird dabei die inzwischen kaum mehr umstrittene Tatsache, dass es sich bei IP-Adressen um personenbezogene Daten handelt, die unter die Regeln des Datenschutzes fallen. Aber welche konkreten technischen und rechtlichen Konsequenzen hat diese Einordnung, insbesondere wenn die Daten an Dritte weitergegeben werden?     

Amphiphilic polymer conetworks derived from aqueous solutions for biocatalysis in organic solvents

Activating enzymes in organic solvents is of great interest in current biotechnology. Amphiphilic conetworks have been shown to activate entrapped enzyme molecules in such media. Although successful, the loading of such conetworks is limited by the diffusion of protein molecules. In order to overcome this, we designed a new polyoxazoline-based polymer conetwork that allows the enzyme entrapment during the preparation. To this end, new polymer conetwork soft scaffolds derived from more hydrophilic poly(2-hydroxyethyl acrylate) (PHEA) and more hydrophobic, telechelic poly(2-ethyl-1,3-oxazoline) (PEtOx) were prepared as free-standing membranes. The transparent, nanophasic polymer conetworks showed a selective swelling in aqueous and organic solvents. The enzyme lipase was entrapped by dissolving it in the prepolymer mixture followed by photopolymerization. Compared to the literature known PHEA-l-PDMS systems a 6-fold higher specific activity and a 8-fold higher conetwork activity in organic solvents were obtained. Thus, the novel PHEA-l-PEtOx conetworks are outstanding materials for entrapping and activating enzymes in organic solvents.     

Direct gravure printing of indium tin oxide nanoparticle patterns on polymer foils

A direct gravure printing process for UV-curable indium tin oxide (ITO) nanoparticle patterns on polyethylene terephthalate and polyethylene naphthalate foils is presented for use as transparent electrodes. Both large-area coatings and patterns of ITO with thicknesses from 0.2 to > 1 μm and feature sizes on the order of 100 μm were realized with a sheet resistance down to 400 Ω_□ and a transmission > 85% in the visible. In order to reach the lowest sheet resistance, a post-treatment under inert or reducing conditions at temperatures of 130 to 180 °C was used. Special requirements regarding the gravure printing of electronic material from nanoparticles and potential applications are discussed.     

Looking inside and out: The impact of employee and community demographic composition on organizational diversity climate.

An organization's diversity climate refers to employees' shared perceptions of the policies and practices that communicate the extent to which fostering diversity and eliminating discrimination is a priority in the organization. The authors propose a salient element of the organizational context, the racial composition of the community where the organization is located, serves an important signaling function that shapes the formation of climate perceptions. In a study of 142 retail bank units in the United States, evidence is found for a relationship between the racial composition of an organization's workforce and diversity climate that is moderated by the racial composition of the community where the organization is located. The results suggest that when few racial minorities live in the community in which an organization is embedded, workforce diversity has an impact on employees' diversity climate perceptions. As racial minority popular share increases, workforce diversity tends to lose this signaling value. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

What Does Grid Computing Cost?

Grid computing has gained considerable attention in research and industry. High expectations are associated with the approach. However, so far only few papers have been published about the costs caused by Grid computing. In this article we pursue two main goals: to analyze the different types of costs and to determine the total costs of a resource provider. Our approach is based on the discussion of general cost categories that have to be taken into account. We give concrete numbers for the different categories and use these numbers to estimate the costs in two real life Grids: the EGEE project and the Grid of the pharmaceutical company Novartis. A summarizing discussion concludes the paper.