Optimization of hydrogen charging process parameters for an advanced complex hydride reactor concept

Complex hydrides are identified as promising hydrogen storage media with gravimetric capacities up to 10 wt.%. However, the high temperatures required for the initiation of their hydrogen charging process and their slow kinetics prevent their integration in many practical applications. This paper discusses the challenge of addressing these issues by combining this kind of materials with the appropriate metal hydrides. For this purpose, the complex hydride, 2LiNH₂–1.1MgH₂–0.1LiBH₄–3 wt.% ZrCoH₃ (CxH) and the metal hydride, LaNi_4.3Al_0.4Mn_0.3 (MeH) have been selected as reference materials. The studied configuration corresponds to a tubular reactor where the metal hydride and the complex hydride, separated by a gas permeable layer, are embedded respectively in the centre and the annular ring of the reactor. A 1-dimensional finite element model and a dimensionless number comparing the dominance of the kinetics and the heat transfer processes have been developed to optimize the charging process for different thicknesses and volumetric ratios of the studied materials. For the selected cases, the influence of the thermal properties of the complex hydride and the operating conditions on the charging process is assessed. A sensitivity study has shown that the thermal conductivity of the CxH is the most important parameter influencing the hydrogen storage rate if thick MeH and CxH beds are considered. In contrast, the hydrogen loading time is significantly improved by increasing the coolant temperature for small thicknesses of the two storage media. Thereafter, the gravimetric and volumetric capacities resulting from the scale up of the optimized configurations to store 1 kg of hydrogen are calculated and results are discussed taking into account the interdependence of the different studied parameters.     

A secure zero-energy NFC solution for everyday electronic devices

Standby power consumption of electric devices is a major issue. It accounts for 5 % to 14 % of the total residential power consumption. However, applying state-of-the-art power management techniques can reduce this waste of energy drastically. In this paper we present an innovative and secure Near Field Communication (NFC) Interface technique for everyday electronic devices. By integrating this field-powered and secure communication interface, a target device can be switched off during standby. If user interaction is requested, NFC provides the electrical energy to switch on the target device’s power supply and to start the device. Thus, standby power consumption of an NFC enhanced device is eliminated completely. Besides standby power management, our interface features cryptography, innovative hardware abstraction and user interface concepts, and it enables configuration, monitor, and control tasks of the target device.     

An Attempt to Identify the Low Molecular Feruloylated Oligosaccharides in Beer

Ferulic acid (4‐hydroxy‐3‐methoxycinnamic acid), predominantly in ester form in arabinoxylan chains, is the main phenolic acid present in barley and malt. Only about 1% of the total ferulic acid in barley is present in the free form. A number of previous works concerned the contents of free and esterified ferulic acid in a broad range of popular beers, but there is little information about the possible composition of feruloylated oligosaccharides in beers. The aim of this preliminary work was to purify the feruloylated oligosaccharides from lager beers (by the means of preparative chromatography) followed by composition elucidation using TLC, HPLC with RI or UV detection and ¹H‐NMR. Indeed, the qualitative analyses of isolated fractions from beer revealed that the fractions contained ferulic acid in the ester form (as proven after mild alkaline hydrolysis). It was also shown that molecular masses of oligosaccharides present in the purified beer fractions were similar to the masses of arabinose and xylooligosaccharides in the range of xylose to xylohexaose. Although a number of purified beer samples contained oligosaccharides of higher molecular masses, these were not further characterized. Taking under consideration the presented results, it can be concluded that beer can be a good source of feruloylated oligosaccharides, significant in the context of human health benefits.     

Formation of nucleoli in interspecies nuclear transfer embryos derived from bovine, porcine, and rabbit oocytes and nuclear donor cells of various species

The most successful development of interspecies somatic cell nuclear transfer (iSCNT) embryos has been achieved in closely related species. The analyses of embryonic gene activity in iSCNT embryos of different species combinations have revealed the existence of significant aberrations in expression of housekeeping genes and genes dependent on the major embryonic genome activation (EGA). However, there are many studies with successful blastocyst (BL) development of iSCNT embryos derived from donor cells and oocytes of animal species with distant taxonomical relations (inter-family/inter-class) that should indicate proper EGA at least in terms of RNA polymerase I activation, nucleoli formation, and activation of genes engaged in morula and BL formation. We investigated the ability of bovine, porcine, and rabbit oocytes to activate embryonic nucleoli formation in the nuclei of somatic cells of different mammalian species. In iSCNT embryos, nucleoli precursor bodies originate from the oocyte, while most proteins engaged in the formation of mature nucleoli should be transcribed from genes de novo in the donor nucleus at the time of EGA. Thus, the success of nucleoli formation depends on species compatibility of many components of this complex process. We demonstrate that the time and cell stage of nucleoli formation are under the control of recipient ooplasm. Oocytes of the studied species possess different abilities to support nucleoli formation. Formation of nucleoli, which is a complex but small part of the whole process of EGA, is essential but not absolutely sufficient for the development of iSCNT embryos to the morula and BL stages.     

Hochwasserrückhalteanlagen im Südburgenland

In Southern Burgenland, located in southeast Austria, the annual precipitation amounts to roughly 800 mm; when heavy rains hit, daily precipitation maxima can be as high as 100 mm. These extreme precipitation events in the middle basin of the Rába (Raab) River produce not only extremely high, concentrated peak discharge values, but also flood waves with considerable transport loads. So as to avoid flood damages, above all preventive measures in the form of flood retention structures are implemented as close to the at-risk settlements as possible.     

Rock anchorage technology

The technique of rock anchorage is increasingly used nowadays in foundations and in driving underground works. This article on the various types of anchor, methods of installation and corrosion protection, is by a member of the Department of Rock Mechanics in the National Building Geology Corporation in Prague, where extensive studies have been made of the techniques described.     

Muon-spin-relaxation study of organic semiconductor spiro-linked compound

We report on muon-spin-relaxation (μSR) experiment of organic semiconductor spiro-linked compound 2′,7′-bis(N,N–diphenylamino)-2-(5-(4–tert-butylphenyl)-1,3,4-oxadiazol-2-yl)-9,9-spirobifluorene (Spiro-DPO) measured at temperatures between 8 and 300 K and at longitudinal fields up to 395 mT in order to study charge transport properties in organic semiconductor. The μSR time spectra were analyzed by using Risch and Kehr (RK) function and it indicates a transition from one-dimensional hopping transport of charge carriers at low temperatures to two- or three-dimensional hopping transport at high temperatures (>75 K).     

Pretreatment of sunflower stalks for biogas production

Sunflower stalks were subjected to commercial-scale pretreatment by hot-water maceration and steam-explosion technology to enhance biogas production. The technology involved does not require heavy construction nor does it consume any additional energy, chemicals, or rare catalysts. Process parameters regarding the mass flow, operating temperature, retention times, hydromodule, pressure, micropore area, formation of inhibitors, and especially the methane yields were plotted in detail to allow further optimization of the design. It was found that the optimal settings should come from both the macerator and steam-explosion subunits because various synergistic effects may be achieved.