A cautionary note on thermal runaway reactions in mixtures of 1-alkyl-3-methylimidazolium ionic liquids and N-methylmorpholine-N-oxide

Nicht verfügbarN-Methylmorpholine-N-oxide (NMMO) cannot be completely separated by extraction from mixtures with common 1,3-dialkylimidazolium ionic liquids (ILs) due to strong ionic interactions between the two components. At elevated temperatures, above approx. 90 C, especially under dry conditions and in the presence of acid, alkylating or acylating agents, remaining NMMO in ILs tends to undergo autocatalytic degradation. This is a highly exothermic, unstoppable process that results in explosions, flames, and complete charring of the reaction mixtures. Thus, caution must be exercised when drying or heating ILs that were in previous contact with NMMO, and the absence of amine oxide must be confirmed to avoid potential danger.(VLID)192930

Exploring Alkyl-O-Alkyl Ether Structures in Softwood Milled Wood Lignins

Recent studies have suggested that there are significant amounts of various alkyl ether (Alk-O-Alk; Alk = alkyl) moieties in a spruce native lignin preparation, milled wood lignin (SMWL). However, the comprehensive NMR assignment to these moieties has not been addressed yet. This study focused on investigating different types of Alk-O-Alk structures at the alpha-and gamma-positions of the lignin side chain in an heteronuclear single-quantum coherence (HSQC) spectrum of SMWL using experimental NMR data of lignin and synthesized model compounds. Ambiguous structural features were predicted by computer simulation of 1H and 13C NMR spectra to complement the experimental NMR data. As a result, specific regions in the HSQC spectrum were attributed to different Alk-O-Alk moieties of Alk-O-Alk/beta-O-4 and Alk-O-Alk/beta-beta ' structures. However, the differences between the specific regions were rather subtle; they were not well separated from each other and some major lignin moieties. Furthermore, SMWL contained a large variety of Alk-O-Alk moieties but in minute individual amounts, resulting in rather broad, superimposing resonances. Thus, evaluation did not allow assigning individual types of Alk-O-Alk moieties from the HSQC spectra; instead, they were quantified as total (alpha-and gamma-linked) Alk-O-Alk based on the balance of structural units in the 13C NMR spectra. At last, potential formation mechanisms of various Alk-O-Alk ether structures in lignin biosynthesis, lignin aging, and during ball milling of wood were and discussed.Peer reviewe

COMPARING ESTIMATED AND MEASURED MUSCLE ACTIVATION DURING HIGHLY DYNAMIC AND MULTIDIRECTIONAL MOVEMENTS - A VALIDATION STUDY

The purpose of this study was to validate muscle activation of the lower extremities computed in AnyBodyMT with measured muscle activations (EMG) in highly dynamic movement tasks. Ten participants performed walking, jogging, sprinting and cutting tasks. Kinetic, kinematic and EMG data were captured for 8 muscles of the dominant leg. The average correlation coefficient (CC) was 0.51 (max.: 0.83, min.: -0.05) with 71% of all trials showing moderate to very good compliance. The average mean absolute error (MAE) was 1.32 (max.: 3.71, min.: 0.17). Co-contraction, precision of the muscle recruitment algorithm, electromechanical delay and anthropometrical measures may have affected the results. The estimation of computed muscle activation can be a suitable method for certain muscles considering highly dynamic movement tasks

Cellulose / Drying of a cellulose II gel: effect of physical modification and redispersibility in water

nicht verf\ufcgbarThe agglomeration of cellulosic materials upon drying, often called hornification, causes a reduction of water retention, among other undesired effects. It is one of the main issues in industrial cellulose processing, especially with regard to nanocelluloses. As a consequence, high transportation and storage costs arise since nanocelluloses need to remain in aqueous suspensions unless trade-offs in reactivity, redispersibility and surface properties are accepted. In this study, different drying strategies for TENCEL\uae gel, a nanostructured gel derived from the Lyocell process consisting of spherical particles, are compared and evaluated. First, freeze-drying with consideration of the influence of freezing temperature and the use of tert-butanol as cryo-protectant, and second, simple oven-drying at 60 \ub0C. Surprisingly, oven-dried xerogels showed higher water retention values and also better colloidal stability than the cryogels. This is in stark contrast to cellulose nanofibrils for which freeze-drying has been shown to be significantly superior to oven drying in terms of redispersibility. For the TENCEL\uae gel, oven-drying was thus selected and the influence of additives on the redispersibility of the cellulose II gel was studied by means of the common water retention value, particle size, colloidal stability, appearance of the redispersed gel and viscosity. The addition of the polysaccharides carboxymethyl cellulose or xanthan showed the most promising results with regard to redispersibility. Also sucrose and ammonium bicarbonate provided higher colloidal stabilities than that of the untreated TENCEL\uae gel. The redispersibility of the cellulose II xerogels could thus be significantly improved by simple and cost-efficient mixing with additives prior to drying

Praktizierte Humanität im Krieg und bei Katastrophen : das Rote Kreuz zwischen Anspruch und Wirklichkeit

Im Sommersemester 2011 fand an der Eberhard Karls Universität Tübingen im Rahmen des Studium Generale eine Vortragsreihe unter dem Titel „Praktizierte Humanität im Krieg und bei Katastrophen – Rotes Kreuz zwischen Anspruch und Wirklichkeit“ statt. Unterstützt wurde das Projekt des Kreisverbands „Rotes Kreuz Tübingen“ von Prof. Dr. Thomas Potthast vom Internationalen Zentrum für Ethik in den Wissenschaften (IZEW). Die Vorträge der verschiedenen Referenten und Referentinnen zu Historie, aktuellen Einsatzszenarien, nachhaltiger Entwicklungsarbeit sowie ethischen Werten und moralische Grenzen des Roten Kreuz wurden thematisiert, diskutiert und in vorliegendem Band veröffentlicht. Darin beinhaltet sind zudem kurze Porträts der Autoren und Autorinnen.In the summer semester of 2011, a lecture series entitled "Practiced Humanity in war and disasters – Rotes Kreuz between demand and reality" took place at the Eberhard Karls University Tübingen within the framework of the Studium Generale. The project of the district association "Rotes Kreuz Tübingen" was supported by Prof. Dr. Thomas Potthast of the International Centre for Ethics in the Sciences and Humanities (IZEW). The lectures of the various speakers on history, current deployment scenarios, sustainable development work, ethical values and moral limits of the Rotes Kreuz were thematized, discussed and published in this volume. It also contains short portraits of the authors

Bildung für Nachhaltige Entwicklung in Reallaboren: Die bildungsbezogenen Angebote des „Energielabors Tübingen“ in der Kinder-Uni Tübingen

In Reallaboren forschen und lernen WissenschaftlerInnen und BürgerInnen gemeinsam für Nachhaltige Entwicklung. Welche Rolle Bildung für Nachhaltige Entwicklung (BNE) dabei spielen kann, wird im vorliegenden Beitrag am Beispiel der Angebote des „Energielabor Tübingen“ für die Kinder-Uni diskutiert. BNE trägt im Energielabor bei allen Beteiligten dazu bei, Bewusstsein und Kompetenzen für Nachhaltige Entwicklung weiter zu entwickeln. Zu den Beteiligten zählen auch Kinder, die als „nächste Generation“ und Multiplikatoren für Nachhaltige Entwicklung Adressaten der BNE sind. Sie sollten stärker als bislang in Reallabore eingebunden werden.In „Urban Transition Labs“, scientists and citizens research and learn together to promote sustainable development. This paper discusses what role Education for Sustainable Development (ESD) could play in Urban Transition Labs. It uses the contributions of the project „Energy Lab Tübingen“ to the Children’s University Tübingen as an example. Here, ESD creates and develops awareness and skills in favour of sustainable development. This concerns all participants, including children. Children are the „next generation” and multipliers for sustainable development. As such, they are addressees of ESD, and they should be integrated deeper into project forms like Urban Transition Labs

Chapter 11 - Education for Sustainable Development as a Challenge for Teacher Education: Implementation at the University of Tübingen

This chapter focuses on Education for Sustainable Development (ESD) and its implementation in the education of academic high school (Gymnasium) teachers at the University of Tübingen in Germany. First, an overview is provided of ESD's political context and its implementation in Germany's teacher education, particularly in the state of Baden-Württemberg, where Tübingen is located. Then, the results of the analysis of ESD implementation and related concepts in teacher education at the University of Tübingen are presented

Cellulose / Surface properties and porosity of highly porous, nanostructured cellulose II particles

Abstract in deutscher Sprache nicht verf\ufcgbarRecently, a new member of the nanocellulose family was introduced, a cellulose II gel consisting of nanostructured and spherical particles. In this study, we compared two different drying techniques to obtain highly porous powders from this gel with preserved meso- and macroporous nanostructure: first, freeze-drying after solvent exchange to tBuOH and second, supercritical drying of the respective EtOH alcogel. The approaches yielded aerogel powders with surface areas of 298 and 423 m2/g, respectively. Both powders are amphiphilic and possess energetically heterogeneous surfaces with dominating dispersive term of the surface energy in the range of 50\u201352 mJ/m2, as determined by a combination of physicochemical surface characterization techniques, such as iGC, BET and SEM. Despite the lower surface area, the cheaper and more widespread method, freeze-drying, yields a more polar and reactive cryogel