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We investigated the solid state reaction of 30-nm and 100-nm-thick silicide layers on single-crystalline silicon in the temperature range between 650 and 800°C using transmission electron microscopy and atomic force microscopy. Sheet resistance measurements were used to observe the effect of the reaction temperature on the layer properties and to perform a systematic study on the thermal stability. At the lower reaction temperature good quality layers were produced with quite small grains. The specific resistivity is as low as 15 μΩ cm and the interface to the silicon substrate is quite flat. These favourable properties lead to a high thermal stability. The processed layers are stable in the temperature range between 850 and 950°C. When the layer thickness is increased to 100 nm, the stability range extends by about 250°C. The deterioration rate of 30-nm and 100-nm-thick silicide layers was deduced from sheet resistance measurements. The activation energy for the electrical degradation of the layer due to layer agglomeration was found to be nearly independent of the thickness.

We present the determination of the alkaloid hordenine and its forensic relevance as a qualitative and quantitative marker for beer consumption. A simple, rapid and sensitive ultra-performance liquid chromatography (UPLC)-tandem mass spectrometry (MS/MS) method for the determination of hordenine in human serum samples was developed and validated. The application was tested with serum samples after enzymatic cleavage. After addition of the synthesized internal standard hordenine-D 4, a liquid-liquid extraction with dichloromethane and diethyl ether was performed. Chromatographic separation was conducted with a Waters Acquity® UPLC system with gradient elution on an Agilent Eclipse XDB-C18 column (4.6 mm × 150 mm, 5-μm particle size). For quantification, a Waters Acquity® TQ detector (version SNC 627) with a positive electrospray ionization probe and multiple reaction monitoring mode was used. A flow rate of 0.4 ml/min was applied. The retention time for both the analyte and the internal standard was 3.67 min. Linearity was demonstrated from 0.2 to 16 ng/ml (R(2) > 0.999). The lower limit of quantification was 0.3 ng/ml in serum. Matrix effects and extraction recoveries for low and high concentrations were within acceptable limits of 75-125% and 50%, respectively. To the best of our knowledge there is no corresponding method for the determination of hordenine by UPLC-MS/MS in serum. By our drinking studies we demonstrate that beer consumption leads to detectable hordenine concentrations in serum and observed a linear elimination of total hordenine correlating to blood alcohol concentration, which shows that hordenine can be used as a reliable qualitative and quantitative marker for beer consumption. The validated method was successfully applied to serum from actual forensic cases.

Planning the air-terminations for a structure to be protected the use of the rolling-sphere method (electro-geometrical model) is the best way from the physics of lightning point-of-view. Therefore, international standards prefer this method. However, using the rolling-sphere method only results in possible point-of-strikes on a structure without giving information about the probability of strikes at the individual points compared to others.

Abstract This paper gives an experimental investigation of the effect of climatic conditions on the performance and degradation of crystalline silicon photovoltaic modules under Saharan environment in Adrar region in the south of Algeria. The first part of this study is focused on the analysis and assessment of UDTS 50 PV modules degradation after a long term outdoor exposure to these conditions (more than 12 years). The visual inspection of 62 PV modules has allowed to observe and determine the degradation modes such as, EVA discoloration, delamination, busbar corrosion, cracking of solar cell, glass breakage, AR coating and solder bond. The degradation evaluation of three modules with different defects was also performed, using (I-V/P-V) characteristics and the degradation rates of the parameters (Pmax, Imp, Vmp, Isc, Voc, FF) at Standard test conditions (STC) in order to compare with the nominal data delivered by the manufacturer of photovoltaic panels. Finally, the combination of the partial shading effect and the presence of EVA browning defect was examined to assess the changes in I-V and P-V curves caused by the drop in electrical parameters.

SummaryThe German government has adopted a law that requires sewage plants to go beyond the recovery of phosphorus from wastewater and to promote recycling. We argue that there is no physical global short‐ or mid‐term phosphorus scarcity. However, we also argue that there are legitimate reasons for policies such as those of Germany, including: precaution as a way to ensure future generations’ long‐term supply security, promotion of technologies for closed‐loop economics in a promising stage of technology development, and decrease in the current supply risk with a new resource pool.

AbstractCellulose and lignin nanoparticles are high‐value‐added products obtained from lignocellulosic biomasses through several steps of cellulose purification and lignin extraction. These steps drastically reduce the potential feedstock revenue when carried out as stand‐alone methodologies. To increase biomass yields, we describe here a strategy to design a biorefinery focused on producing cellulose and lignin nanoparticles as main products, but also aim to recover and benefit from other biomass components using only water‐based processes. Sequential pressurized liquid extractions and diluted acid and alkaline treatments were carried out to fractionate elephant grass biomass, yielding (for every 100 g of biomass): 30 g of cellulose pulp (converted to 9 g of cellulose nanocrystals and 9 g of cellulose nanofibers); 10 g of lignin (used to produce 8.5 g of stable colloidal lignin nanoparticles by probe‐sonication in water); 7.5 g of extractives (e.g. sterols and phenolics) and 23 g of xylose (converted to 4.1 g of furfural). Alternatively, to allow for the flexible use of the cellulose fraction in the proposed biorefinery, 22 g of glucose could be produced by enzymatic hydrolysis. The results demonstrate that water‐based processes are suitable for a holistic use of biomass, providing a comprehensive set of high‐value‐added co‐products that are renewable and cost‐effective chemical, cosmetic, food, polymer and pharmaceutical solutions.

Abstract This work presents a numerical study on the performance of a stand-alone adsorption cooling system based on the silica gel/water couple driven by hybrid photovoltaic/thermal (PVT) collectors. This system is intended for the conservation of perishable agricultural products which require air-conditioned premises to preserve them. The weather conditions are those of North Africa (Algiers). Considering the above, this paper aims at analyzing the PVT-Adsorption system with energy storage to guarantee a stabilized production and increase the solar coverage. trnsys was used to simulate the system taking into account hourly series of irradiation and ambient temperature covering one year. The performance study reveals that the DualSun PVT hybrid collectors used provide optimal annual production and that the adsorption cooling system offers more reliable production during summer. The temperature difference between the inside and outside of the cooled enclosure balances supply and demand. The loss analysis of the storage device indicates that losses depend, on the one hand, on the interior/exterior temperature difference of the storage tank with more significant values during the summer season. On the other hand, the losses also depend on the volume of the storage tank which was optimized in order to limit the heat exchange with the surroundings.

Acetic acid bacteria such as Gluconobacter oxydans are used in several biotechnological processes due to their ability to perform rapid incomplete regio- and stereo-selective oxidations of a great variety of carbohydrates, alcohols, and related compounds by their membrane-bound dehydrogenases. In order to understand the growth physiology of industrial strains such as G. oxydans ATCC 621H that has high substrate oxidation rates but poor growth yields, we compared its genome sequence to the genome sequence of strain DSM 3504 that reaches an almost three times higher optical density. Although the genome sequences are very similar, DSM 3504 has additional copies of genes that are absent from ATCC 621H. Most importantly, strain DSM 3504 contains an additional type II NADH dehydrogenase (ndh) gene and an additional triosephosphate isomerase (tpi) gene. We deleted these additional paralogs from DSM 3504, overexpressed NADH dehydrogenase in ATCC 621H, and monitored biomass and the concentration of the representative cell components as well as O2 and CO2 transfer rates in growth experiments on mannitol. The data revealed a clear competition of membrane-bound dehydrogenases and NADH dehydrogenase for channeling electrons in the electron transport chain of Gluconobacter and an important role of the additional NADH dehydrogenase for increased growth yields. The less active the NADH dehydrogenase is, the more active is the membrane-bound polyol dehydrogenase. These results were confirmed by introducing additional ndh genes via plasmid pAJ78 in strain ATCC 621H, which leads to a marked increase of the growth rate.

Zusammenfassung Die Technische Universitat Munchen ist Bauherr und zukunftiger Betreiber der neuen Forschungs-Neutronenquelle FRM-II; die Firma Siemens hat den Generalauftrag zur Erstellung der Anlage. Dieser neue Reaktor FRM-II mit hoher Neutronenflusdichte wird im Jahr 2001 den mehr als 40 Jahre alten Forschungsreaktor FRM in Garching ablosen. Der nachstehende Artikel gibt eine kurze Ubersicht uber die Reaktoranlage FRM-II und das breite Spektrum von forschungs- und anwendungsorientierten Arbeiten. Speziell wird die Konverteranlage beschrieben, die ein schnelles Neutronenspektrum fur medizinische und technische Anwendungen sowie fur medizinische und physikalische Forschungsarbeiten zur Verfugung stellt.