15 research outputs found

    Synthesis of Polyurethanes based on 17 Hydroxy Oleic Acid obtained from Sophorolipids

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    Due to the worldwide shortage of petrochemical based resources, the usage of renewable bio-based raw materials for established and novel products becomes increasingly important.[1] Such bio-based resources are already used for the fabrication of a variety of products, e. g. paper, lubricants, detergents or cosmetics. In the future they are expected to emerge in many more applications in industry and household.[1] A very promising approach relies on the use of glycolipids as a source of hydroxy-oleic acid.[2] Microbial glycolipids are produced for instance via fermentation from natural resources such as plant oils and sugar.[3] After fermentation complex product mixtures are obtained with the composition depending on the microorganism, substrate and fermentation time.[3] The successful use of microbial glycolipids and hydroxy-oleic acid (HOA) derived therefrom as bio-based intermediates requires reliable analytical methods as well as robust manufacturing processes for the synthesis and cleavage of bio-based molecules. In order to obtain hydroxy-oleic acids as bio-based intermediates, the acidic cleavage of microbial derived sophorolipid was investigated. In addition the implementation of HOA in polyurethane (PU) systems was explored

    Lipase catalyzed synthesis of oligomeric diol building blocks utilizing sophorolipid-derived hydroxy fatty acids

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    The synthesis of 17-hydroxy-oleic acid based oligomeric esters was investigated with immobilized Pseudozyma antarctica Lipase B and hexanediol as co-substrate. The effects of different reaction parameters on velocity and product composition at equilibrium conditions were analyzed. The synthesis of oleic acid esters was used as a reference system for initial evaluation of reaction parameters. The reaction with oleic acid and hexanediol was fastest at an enzyme concentration of 5% at 60 °C and high conversions of > 90 % were achieved in non-polar solvents in the presence of molecular sieves. In heptane an oleic acid conversion of 96 % was reached with a final diester to monoester ratio of > 4:1. In syntheses trials with 17-hydroxy-oleic acid the formation of oligomers was verified with GPC, however; conversion was generally lower than with oleic acid. Removal of hydroxyl fatty acid monomers and dimers and the formation ester functionalities could be verified by GC analysis. An increase of the degree of oligomerization was observed simultaneously by GPC analysis. The number-average molecular weight was around 1400 in the best trials corresponding to a degree of oligomerization of around 4 units of hydroxyl-fatty acid attached to a hexanediol core. Though transformations were not complete, the final oligomer size was in the lower range of polyester diols used for polyurethane manufacturing

    The effect of improvisational music therapy on the treatment of depression: protocol for a randomised controlled trial

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    Background. Music therapy is frequently offered to individuals suffering from depression. Despite the lack of research into the effects of music therapy on this population, anecdotal evidence suggests that the results are rather promising. The aim of this study is to examine whether improvisational, psychodynamically orientated music therapy in an individual setting helps reduce symptoms of depression and improve other health-related outcomes. In particular, attention will be given to mediator agents, such as musical expression and interaction in the sessions, as well as to the explanatory potential of EEG recordings in investigating emotion related music perception of individuals with depression. Methods. 85 adults (18–50 years of age) with depression (ICD-10: F 32 or F33) will be randomly assigned to an experimental or a control condition. All participants will receive standard care, but the experimental group will be offered biweekly sessions of improvisational music therapy over a period of 3 months. A blind assessor will measure outcomes before testing, after 3 months, and after 6 months. Discussion. This study aims to fill a gap in knowledge as to whether active (improvisational) music therapy applied to people with depression improves their condition. For the first time in this context, the mediating processes, such as changes in musical expression and interaction during the course of therapy, will be objectively investigated, and it is expected that the results will provide new insights into these processes. Furthermore, the findings are expected to reveal whether music related emotional experiences, as measured by EEG, can be utilized in assessing a depressive client's improvement in the therapy. The size and the comprehensiveness of the study are sufficient for generalizing its findings to clinical practice as well as to further music therapy research. Trial registration. ISRCTN84185937peerReviewe

    Oxygen Crossover in Solid-Solid Heat Exchangers for Solar Water and Carbon Dioxide Splitting: A Thermodynamic Analysis

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    In solar thermochemical redox cycles for H2O/CO2-splitting, a large portion of the overall energy demand of the system is associated with heating the redox material from the oxidation temperature to the reduction temperature. Hence, an important measure to improve the efficiency is recuperation of sensible heat stored in the redox material. A solid-solid heat exchanger can be subject to undesirable oxygen crossover, which decreases the oxygen uptake capacity of the redox material and consequently the system efficiency. We investigate the extent of this crossover in ceria based cycles, to identify, under which conditions a heat exchanger that allows oxygen crossover can improve the system efficiency. In a thermodynamic analysis we calculate the amount of transferred oxygen as a function of the heat exchanger efficiency and show the system efficiency of such a concept. A second law analysis is applied to the model to check the feasibility of calculated points of operation. For the investigated parameter set the heat exchanger design improves the system efficiency by a factor of up to 2.1

    Performance Assessment of a Heat Recovery System for Monolithic Receiver-Reactors

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    The most advanced solar thermochemical cycles in terms of demonstrated reactor efficiencies are based on temperature swing operated receiver-reactors with open porous ceria foams as a redox material. The demonstrated efficiencies are encouraging but especially for cycles based on ceria as the redox material, studies have pointed out the importance of high solid heat recovery rates to reach competitive process efficiencies. Different concepts for solid heat recovery have been proposed mainly for other types of reactors, and demonstration campaigns have shown first advances. Still, solid heat recovery remains an unsolved challenge. In this study, chances and limitations for solid heat recovery using a thermal storage unit with gas as heat transfer fluid are assessed. A numerical model for the reactor is presented and used to analyze the performance of a storage unit coupled to the reactor. The results show that such a concept could decrease the solar energy demand by up to 40% and should be further investigated

    Kommerzialisierung der Wasserstofftechnologie in Baden-WĂŒrttemberg - Rahmenbedingungen und Perspektiven

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    Ziel der Studie war es, potenzielle Einsatzbereiche und Infrastrukturen fĂŒr eine kĂŒnftige Nutzung von Wasserstoff in Baden-WĂŒrttemberg zu identifizieren und die monetĂ€ren sowie klimarelevanten Wirkungen darzustellen. Eine Kommerzialisierung ist voraussichtlich zuerst im Verkehrssektor möglich, weitere Marktpotenziale in der Erdgas- und Chemieindustrie sowie zur RĂŒckverstromung werden erst nach 2030 gesehen. Derzeit existieren erste Kleinserien fĂŒr Brennstoffzellenfahrzeuge, auf Basis derer die Markthochlaufphase in der kommenden Dekade stattfinden könnte. Die erfolgreiche EinfĂŒhrung der Wasserstoffnutzung ist sehr stark abhĂ€ngig von der Entwicklung der Technologie- und Betriebskosten, des vorhandenen Tankstellennetzes und der Effizienz der Energieumwandlung. Diese Studie arbeitet daher mit zwei Szenarien, einem „konservativen“, in dem ein signifikanter Markthochlauf erst nach 2030 erfolgt, und einem „ambitionierten“, in dem im Jahr 2030 bereits 140.000 Brennstoffzellen-Pkw auf den Straßen Baden-WĂŒrttembergs fahren, mit zusĂ€tzlich bis zu 900 brennstoffzellenbetriebenen Stadtbussen und 50 Triebfahrzeugen fĂŒr den Schienenpersonennahverkehr. Das ambitionierte Szenario wĂŒrde die Treibhausgasemissionen im Land um rund 200 kt CO2 pro Jahr mindern. Dies ergibt sich aus der Betrachtung sowohl der Strombereitstellung fĂŒr die Elektrolyseure als auch der Substitution konventioneller Antriebe in den Fahrzeugflotten. Die Emissionsminderung im Verkehr belĂ€uft sich dabei auf rund 380 kt CO2, wĂ€hrend die Annahme einer flexiblen, d.h. sich in einem definierten Rahmen an den Grenzkosten der Stromerzeugung orientierenden Nutzung des Strommixes fĂŒr die Wasserstoffelektrolyse zu zusĂ€tzlichen Emissionen im Stromsektor von rund 180 kt CO2 fĂŒhrt

    Study of a new receiver-reactor cavity system with multiple mobile redox units for solar thermochemical water splitting

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    Solar thermochemical redox cycles could be a path to efficient, large-scale renewable hydrogen production. A new receiver-reactor concept is presented that combines characteristics of the most successful receiver-reactor systems to date, with features of concepts showing the highest efficiency potential. The key features of the system are movable reactive structures in combination with linear transportation systems and dedicated oxidation reactors. The application of several of these units allows the continuous operation of the receiver-reactor and permits the implementation of a solid–solid heat recovery system. Both of these characteristics are important to increase the system efficiency beyond the current state of technology. A numerical model is developed to simulate a basic cubic design version of the new concept and to analyse its performance. Parameter variations are studied amongst others for different cavity sizes, solar concentration factors and numbers of movable reactive structures. By avoiding the cyclic heating of the inert reactor vessel, the model predicts high efficiency values above 14% even for non-optimized designs. Furthermore, the basic concept of the heat recovery system is modelled with heat recovery rates of up to 20% in its most simple implementation. The new concept has the features required for highly performant systems and opens up a large parameter space for reactor design and operation optimization

    Microbial Synthesis of Nonionic Long‐Chain Sophorolipid Emulsifiers Obtained from Fatty Alcohol and Mixed Lipid Feeding

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    Starmerella bombicola is known to produce sub‐terminally hydroxylated lactonic sophorolipids (SLs), while Candida kuoi synthesizes acidic open chain SLs with terminally hydroxylated fatty acids. Upon feeding glucose and fatty alcohols both strains form long‐chain nonionic SLs. According to structure elucidation the SLs consist of a hydroxylated fatty acid esterified with fatty alcohol and linked via a glycoside bond to the diacetylated sophorose unit. Palmityl, stearyl, and oleyl alcohols lead to products with lipid chain lengths of C32 or C36. Oleyl alcohol is the preferred substrate leading to 45 g L−1 of the double unsaturated C36 SL with S. bombicola and 20 g L−1 with C. kuoi. Scale up from shake flask to 1.5 L fermentations is possible and 65 g L−1 long‐chain SLs are obtained with S. bombicola within 7 days. Mixed feeding of oleic acid and a variety of fatty alcohols leads to new long‐chain SLs. In the presence of oleic acid the yeasts do not oxidize the fatty alcohol and thus the production of biosurfactants with tailored chain length is possible. The long‐chain SLs show good emulsification ability of water/paraffin oil mixtures at low energy input and reduced interfacial tension significantly. Practical Applications: Sophorolipids are produced by fermentation on industrial scale focusing on cleaning and detergent applications. Mainly lactonic or anionic open‐chain forms are used today. The new long‐chain SLs presented in this manuscript are accessible with existing production technology and can be produced with high titers from cost‐efficient renewable raw materials. In contrast to the commercial products the long‐chain SLs are more hydrophobic and exhibit a strong emulsification behavior. Therefore they have the potential to broaden the application range of SLs in future. They may be useful as novel emulsifiers for cosmetic creams and lotions, pharmaceutical ointments and food products or may find application in oil spill remediation
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