blue-c Räumlich-immersive Projektions- und 3D Video-Portale für Telepräsenz. Teil 1: Konzept, Hardware und Videoverarbeitung

Zusammenfassung Der folgende Beitrag beschreibt das Design und die Architektur von blue-c, einem Polyprojekt der ETH Zürich, an dem über einen Zeitraum von 4 Jahren bis zu 20 wissenschaftliche Mitarbeiter mitgewirkt haben und insgesamt 9 Doktorarbeiten entstanden sind.     

blue-c Räumlich-immersive Projektions- und 3D Video-Portale für Telepräsenz. Teil 2: Kommunikation, Systemleistung und Anwendungen

Ohne Zusammenfassung     

Taking into account the inclusions' size in lightweight concrete compressive strength prediction

This paper deals with the mix design and mechanical properties of very lightweight concrete (LWC) made of expanded polystyrene spheres (EPS) and very high performance matrix. To avoid the segregation of EPS spheres in the concrete, it is necessary to adjust the matrix threshold by modifying the superplasticizer dosage. Based on experimental data obtained on different EPS concrete, it is shown that the lower the inclusion size, the higher the compressive strength of the hardened concrete. An empirical model is proposed, to take into account these experimental results. Young's modulus was also measured, it was found that its evolution against strength followed usual physical models, like the well-known Hashin's sphere model, and not an empirical one. Finally, a simulation, based on criteria outlined in the paper, shows that quite new concretes can be proposed in a range of strength versus specific gravity not yet achieved.     

Electro‐optical study of a ×1024 concentrator photovoltaic system

Concentrator photovoltaic (CPV) systems are one of the most promising technologies for future energy supply. Several studies reported the interest of using a Fresnel lens coupled with a secondary optical element in such a system. For high concentration factor, the optimization of the optical configuration plays a key role regarding electrical performances. On the other hand, the thermal management of the solar cell is also critical to ensure a better module efficiency. This paper presents a study of a ×1024 CPV system performances and a methodology for estimating the optical chain efficiency, the cell temperature impact and the alignment requirements. Module efficiencies were then measured as a function of the cell temperature and correlated to optical performances through current‐tension characterizations under real solar illumination conditions and the estimation of the power density received by the solar cell. The system yield was up to 27% for a cell temperature around 30 °C, confirming that high concentration ratio should be of great interest in the near future. A 1D model was also developed in order to quantify the possible improvements of this CPV system. Using a solar cell with an efficiency of 36.7% at ×600, we then demonstrated that the ×1024 CPV system could reach up to 30% in standard test conditions. Copyright © 2012 John Wiley & Sons, Ltd.     

Comparison of the influence of corneo-scleral and scleral lenses on ocular surface and tear film metrics in a presbyopic population

Purpose

To assess and compare the effect of the corneo-scleral lenses (C-ScL) and scleral lenses (ScL) on tear film parameters and central corneal thickness (CCT) in healthy presbyopic subjects.

Uncertainties associated to measurements of inherent optical properties in natural waters

Monte Carlo simulations are used to explain and quantify the errors in inherent optical properties (IOPs) (absorption and attenuation coefficients) measured using the WET Labs AC-9 submarine spectrophotometer, and to assess correction algorithms. Simulated samples with a wide range of IOPs encountered in natural waters are examined. The relative errors on the measured absorption coefficient are in general lower than 25%, but reach up to 100% in highly scattering waters. Relative errors on attenuation and scattering coefficients are more stable, with an underestimation mainly driven by the volume scattering function. The errors in attenuation and scattering spectral shapes are small.     

BaMgAl10O17 as Host Matrix for Mn in the Catalytic Combustion of Methane

BaMgAl₁₀O₁₇ (BMA) solid has been prepared by a sol–gel process: after calcination at 1200 °C a regular structure is obtained along with BET area of 13 m²g^?1. Unexpectedly this solid is active in the catalytic combustion of methane, and its activity is comparable to the activity of other hexaaluminates containing transition metal ions. This activity may be due to oxygen ion diffusion through the mirror plane in relation with a charge compensation mechanism induced by the presence of Mg²⁺ ions. The introduction of Mn ions does not alter the structure but leads to the same phenomenon due to the presence of Mn²⁺ ions. A minor amount of Mn³⁺, revealed by hydrogen TPR and by reflectance spectroscopy, is responsible for an enhanced oxidation activity and a lowering of the activation energy. Such BMA materials may have interesting properties as oxidation catalyst.     

Identifizierung von Emulgatoren mittels Gaschromatographie

Zusammenfassung Die Identifizierung der durch Hydrolyse entstandenen Einzelbausteine von Emulgatoren mittels Gaschromatographie wird beschrieben. Die gute Auftrennung der Einzelbausteine erlaubt weitgehende Rückschlüsse auf die Art der untersuchten Emulgatoren. Die verwendeten Methoden wurden meist zum Nachweis anderer Stoffklassen veröffentlicht und wurden entsprechend modifiziert.

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Identification of emulsifiers by gas-chromatographie

Summary The authors describe with the aid of gaschromatography the identification of component parts of emulsifiers resulting from hydrolysis. The easy separation of the components enables far-reaching conclusions about the type of emulsifiers being analysed. The methods used usually had been published for the identification of other substances and were adapted for the purpose.

     

Enzyme-friendly, mass spectrometry-compatible surfactant for in-solution enzymatic digestion of proteins

Improved in-solution tryptic digestion of proteins in terms of speed and peptide coverage was achieved with the aid of a novel acid-labile anionic surfactant (ALS). Unlike SDS, ALS solubilizes proteins without inhibiting trypsin or other common endopeptidases activity. Trypsin activity was evaluated in the presence of various denaturants; little or no decrease in proteolytic activity was observed in 0.1-1% ALS solutions (w/v). Sample preparation prior to mass spectrometry and liquid chromatography analysis consists of sample acidification. ALS degrades rapidly at low-pH conditions, which eliminates surfactant-caused interference with analysis. Described methodology combines the advantages of protein solubilization, rapid digestion, high peptide coverages, and easy sample preparation for mass spectrometry and liquid chromatography analyses.     

Evidence of a tetradocosahexaenoic cardiolipin in some marine bivalves

Separation of phospholipid classes in lipid extracts from the scallop Pecten maximus, the Pacific oyster Crassostrea gigas, and the blue mussel Mytilus edulis was conducted using HPLC. An isolated polar lipid fraction was found to contain a very high level of DHA, up to 80 mol% of the total FA. MS with electrospray ionization in the positive-ion mode, tandem MS (MS-MS) and multidimensional NMR spectroscopy were used to analyze the detailed chemical structure of this polar lipid fraction. The isolated fraction contained exclusively cardiolipin (CL) molecules, predominantly in a form with four docosahexaenoyl chains (Do₄CL). To the best of our knowledge, this is the first time that such a CL form has been analytically characterized and described in these three bivalve species. This tetradocosahexaenoic CL is presumed to reflect a specific adaptation in bivalves that enhances the structural and functional mechanisms of biomembranes in response to variations in environmental conditions (temperature, salinity, emersion).