Potential use of deep eutectic solvents to facilitate lignocellulosic biomass utilization and conversion

High reliance on crude oil for energy consumption results in the urgent need to explore and develop alternative renewable sources. One of the most promising routes is the transformation of biomass into biofuels and chemicals. The introduction of deep eutectic solvents in 2004 received a considerable amount of attention across different research fields, particularly in biomass processing. The effectiveness of deep eutectic solvents in breaking down the recalcitrant structure in biomass highlights its impact on the transformation of biomass into various value-added products. In addition, deep eutectic solvents are widely regarded as promising “green” solvents due to their low cost, low toxicity, and biodegradable properties. In this paper, some background information on lignocellulosic biomass and deep eutectic solvents is given. Furthermore, the roles of deep eutectic solvents in biomass processing are discussed, focusing on the impacts of deep eutectic solvents on the selectivity of chemical processes and dissolution of biomass. This review also highlights the advantages and limitations of deep eutectic solvents associated with their usage in biomass valorization.     

Radar placement based on a geometric uncertainty multiplier reduction criterion

In this paper the problem of retrieving wind field information from Doppler radar data motivates the formulation of a method to design radar network configurations. The problem of estimating wind velocities from radar data is posed and used to construct a certain retrieval operator. This operator contains a factor that may be interpreted as an uncertainty multiplier. It depends on the geometry of the configuration of the radar network. The uncertainty multiplier is shown to vary continuously with perturbations of the network configuration. It is also shown to be a generalization of the Doppler angle condition used in meteorology. Numerical examples are presented to determine a network of five radars minimizing the uncertainty multiplier for the problem. Also, a configuration of sites is determined that maximizes the area of the Doppler region.     

Quantitative Infrarot-Messungen an Polyvinylchlorid-Weichmacher-Systemen

Zusammenfassung Methoden zur infrarotspektroskopischen Untersuchung von weichgemachten Polyvinylchlorid-(PVC-)Folien werden beschrieben. Die Ergebnisse von Intensitätsmessungen an Folien verschiedener PVC-Sorten und an Di-alkylphthalsäureestern werden mitgeteilt und diskutiert. Es wird gezeigt, daß in PVC-Phthalsäureester-Systemen Schlüsselfrequenzen (für PVC1430 cm^–1, für Phthalate 1728 cm. ^–1) vorhanden sind, die in einem technisch interessierenden Konzentrationsbereich dem Lambert-Beerschen Gesetz folgen und daher zur Konzentrationsbestimmung von Phthalsäureestern in PVC-Folien geeignet sind.Die für die Durchführung dieser Arbeit notwendigen apparativen Einrichtungen und die allgemeinen Sachmittel wurden uns von der Deutschen Forschungsgemeinschaft, dem Fonds der Chemie und vor allem von einem Arbeitskreis einiger deutscher Kabelwerke zur Verfügung gestellt. Wir danken den genannten Stellen für ihre wesentliche Hilfe.Auszugsweise vorgetragen von H. Loew     

Zur Messung der dielektrischen Verluste zur Bestimmung der Wechselwirkungen in Polyvinylchlorid-Weichmacher-Systemen

Zusammenfassung Am Beispiel des Systems Dioctylphthalat-Polyvinylchlorid wird gezeigt, da? der Verlauf der dielektrischen Verluste über der Temperatur nicht als Beweis für die Existenz „gebundenen“ und „freien“ Weichmachers in weichgemachtem Polyvinylchlorid gewertet werden kann. Die vorhandenen zwischenmolekularen Kr?fte zwischen den Komponenten k?nnen zwar zu Abweichungen einer idealen statistischen Verteilung der Systempartner, aber nicht zu einer Ausbildung st?chiometrisch zusammengesetzter Assoziate führen. Für die Mischungen gelten die Gesetze der Mischphasenthermodynamik (11).     

Micro-lens arrays generated by UV laser irradiation of doped PMMA

Micro-lenses with well-defined optical parameters are generated on polymethylmethacrylate (PMMA) substrates doped with diphenyltriazene (DPT) by controlled use of a swelling effect generated under conditions of subablative excimer laser illumination. The surface profiles depend on the laser spot size and energy density. A sensitively balanced combination of matrix softening, substrate volume expansion due to photochemical nitrogen release, and surface tension is responsible for the final shape of the lenses. Complete arrays of identical lenses with 15 μm diameters and a focal length of 30 μm are produced by irradiation of (0.25 wt. %) DPT-PMMA with a single laser pulse at a wavelength of 308 nm and a fluence of 3 J/cm². It is shown experimentally and theoretically that appropriate volume expansion is possible without introducing internal light scattering due to the formation of small bubbles. Received: 7 April 1999 / Accepted: 8 April 1999 / Published online: 5 May 1999     

Bestimmung des Harnstoffs

Ohne Zusammenfassung