On the deflagration of aluminium/KClO4 mixtures

Explosive properties of KClO₄/Al-mixtures (60/40) were studied using 15 different types of Al powders. The explosions were photographed and the propagation speed was measured. The detonation and detonation isentrope properties of the mixtures were calculated and the results compared to the measured data. A condensed phase detonation was not detected but shock waves were most likely present in the gas phase. The results indicate that aluminium powder is not able to sustain detonation at all. Additionally, powder with a surface area less than 5 m²/g will not even deflagrate reliably as a mixture with potassium perchlorate.     

C/C-SiC component for metallic phase change materials

Thanks to their high energy density and thermal conductivity, metallic Phase Change Materials (mPCM) have shown great potential to improve the performance of thermal energy storage systems. However, the commercial application of mPCM is still limited due to their corrosion behavior with conventional container materials. This work first addresses on a fundamental level, whether carbon-based composite-ceramics are suitable for corrosion critical components in a thermal storage system. The compatibility between the mPCM AlSi₁₂ and the Liquid Silicon Infiltration (LSI)-based carbon fiber reinforced silicon carbide (C/C-SiC) composite is then investigated via contact angle measurements, microstructure analysis, and mechanical testing after exposure. The results reveal that the C/C-SiC composite maintains its mechanical properties and microstructure after exposure in the strongly corrosive mPCM. Based on these results, efforts were made to design and manufacture a container out of C/C-SiC for the housing of mPCM in vehicle application. The stability of the component filled with mPCM was proven nondestructively via computer tomography (CT). Successful thermal input- and output as well as thermal storage ability were demonstrated using a system calorimeter under conditions similar to the application. The investigated C/C-SiC composite has significant application potential as a structural material for thermal energy storage systems with mPCM.     

Cone Photoreceptor Loss in Light-Damaged Albino Rats

We investigated the etiology of decreased cone-driven vision in a light damage (LD) model of retinal degeneration. To induce slow, moderate degeneration, albino rats underwent low-intensity light exposure for 10 days. Electroretinography was utilized to assess physiologic function of the rod- and cone-driven retinal function in LD and control rats. Immunohistochemistry targeting cone arrestin allowed for quantification of cone density and for comparison of the decline in function. Photoreceptor loss was quantified by outer nuclear layer thickness decreases, as observed by optical coherence tomography and histology. The LD rats showed decreased rod- and cone-driven function with partial recovery 30 days after cessation of light exposure. In addition, LD rats showed decreased cone photoreceptor densities in the central retinal region compared to control rats. Our results demonstrate that the loss of cone-driven visual function induced by light damage is at least partially due to the death of cone photoreceptors.     

Über die Katalyse der Cooxidation von cis-Oct-4-en und n-Butyraldehyd

The Catalysis of the Co-Oxidation of cis-Oct-4-ene and n-Butyric Aldehyde The co-oxidation of cis-oct-4-ene and n-butyric aldehyde in the absence of catalysts, or in the presence of molybdenum and Co(acac)₃, resp., was studied in dependence on the aldehyde/olefin ratio, on the temperature and other reaction conditions. Under the same conditions, the noncatalyzed co-oxidation converted 50%, the MoO₂(acac)₂-catalyzed one 68%, and the Co(acac)₃-catalyzed one 40% of the reacted olefin into the epoxide. The cis/trans-epoxide ratio in the molybdenum-catalyzed co-oxidation was nearly 2 independent of the aldehyde/olefin ratio. In the non-catalyzed co-oxidation the cis/trans-epoxide ratio depends linearly on the aldehyde/olefin ratio (cis/trans E. = 0,58 + 0,90 n/n). From these dependences we can conclude that the homolytic mechanism of epoxide formation decreases and the polar mechanism (Priležaev-reaction) increases with increasing aldehyde/olefin ratio. Optimization of the epoxide yields according to a Box-Hunter experimental plan gave the following reaction conditions to yield 95% epoxide based on reacted olefin: 70°C, Δn_S/n = 0,49, n/n = 3,5 · 10⁻³, n/n = 0,53. The co-oxidation in the presence of other molybdenum catalysts of the chloro-nitrosyl-complex type and of the carbonyl-complex type as well as the co-oxidation with other aldehydes were studied, too.     

Chancen europäischer Standards für die Zertifizierung?

Ein international erfolgreiches Schema für Cybersicherheits-Zertifizierungen bedarf akzeptierter und implementierter Sicherheitsstandards. Dieser Artikel erörtert kritisch die komplexen Anforderungen hinsichtlich der Vollständigkeit, Dynamik und Durchsetzung aus europäischer Perspektive und zeigt am Beispiel der eIDAS-Verordnung die Herausforderungen bei der Umsetzung auf.     

Löschen im Internet – rechtlich gefordert und technisch möglich!

Die im Art. 17 der Datenschutz-Grundverordnung (DSGVO) enthaltene Regelungen für das Löschen, insbesondere die Pflicht, Dritte über die Löschanfragen zu informieren, sind mit einem hohen Aufwand für die Verantwortlichen verbunden, sodaßs sie ohne eine technische Unterstützung in der Praxis nicht umgesetzt werden können. Die zurzeit jedoch fehlenden technischen Lösungen führen zu einer Lücke zwischen den Rechtsvorschriften und den derzeitigen technischen Möglichkeiten, während die DSGVO ab Mai 2018 anzuwenden ist. Um diese Lücke zu schließen, wird im Folgenden zunächst analysiert, welche Möglichkeiten im Allgemeinen bestehen, das Löschen im Internet gemäß Art. 17 technisch umzusetzen. Anschließend wird eine Lösung für die Verteilung der Löschanfragen an die Verantwortlichen vorgestellt, das auf der Kombination der Technik mit dem Gesetz beruht und sowohl den Betroffenen als auch den Verantwortlichen ein Werkzeug zur Unterstützung des Art. 17 zur Verfügung stellt.     

Modeling the Electrical Conductive Paths within All-Solid-State Battery Electrodes

All-solid-state batteries constitute a very promising energy storage device. Two very important properties of these battery cells are the ionic and the electrical conductivity, which describe the ion and the electron transport through the electrodes, respectively. In this work, a numerical method is presented to model the electrical conductivity, considering the outcome of discrete-element method simulations and the intrinsic conductivities of both the active material particles and the conductive additive particles. The results are calibrated and validated with the help of experimental data of real manufactured electrodes. The tortuosity, which strongly influences the ionic conductivity, is also presented for the analyzed electrodes, taking their microstructure into account.     

Chemopreventive Potential of Wild Lowbush Blueberry Fruits in Multiple Stages of Carcinogenesis

ABSTRACT: Wild lowbush blueberry fruit extract was fractionated using vacuum chromatography and analyzed for chemopreventive potential using bioassays that test the ability of compounds to inhibit the initiation, promotion, and progression stages of carcinogenesis. A fraction containing phytosterols was active against the initiation stage (quinone reductase assay). However, more polar compounds were inhibitors of later stages of carcinogenesis; a fraction containing flavan-3-ols and fractions containing mainly anthocyanins, phenolic acids, flavan-3-ols, and some proanthocyanidin dimers demonstrated activity against the promotion stage (cyclooxygenase and ornithine decarboxylase assays, respectively), and a proanthocyanidin-rich fraction demonstrated antiproliferation activity (inhibition of cancerous murine hepatocyte proliferation is associated with the progression stage). These results indicate that lowbush blueberries contain a range of compounds that have bioactivity against multiple stages of carcinogenesis, and different types of phenolic compounds are active at different stages.