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Publikation Organic photovoltaics: Potential fate and effects in the environment(Elsevier, 2012) Zimmermann, Yannick-Serge; Schäffer, Andreas; Hugi, Christoph; Fent, Karl; Corvini, Philippe; Lenz, MarkusIn times of dwindling fossil fuels it is particularly crucial to develop novel “green” technologies in order to cover the increasing worldwide demand for energy. Organic photovoltaic solar cells (OPVs) are promising as a renewable energy source due to low energy requirement for production, low resource extraction, and no emission of greenhouse gasses during use. In contrast to silicium-based solar cells, OPVs offer the advantages of light-weight, semi-transparency and mechanical flexibility. As to a possible forthcoming large-scale production, the environmental impact of such OPVs should be assessed and compared to currently best available technologies. For the first time, this review compiles the existing knowledge and identifies gaps regarding the environmental impact of such OPVs in a systematic manner. In this regard, we discuss the components of a typical OPV layer by layer. We discuss the probability of enhanced release of OPV-borne components into the environment during use-phase (e.g. UV- and biodegradation) and end-of-life phase (e.g. incineration and waste disposal). For this purpose, we compiled available data on bioavailability, bioaccumulation, biodegradation, and ecotoxicity. Whereas considerable research has already been carried out concerning the ecotoxicity of certain OPV components (e.g. nanoparticles and fullerenes), others have not been investigated at all so far. In conclusion, there is a general lack of information about fate, behavior as well as potential ecotoxicity of most of the main OPV components and their degradation/transformation products. So far, there is no evidence for a worrying threat coming from OPVs, but since at present, no policy and procedures regarding recycling of OPVs are in action, in particular improper disposal upon end-of-life might result in an adverse effect of OPVs in the environment when applied in large-scale.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Augmented feedback system to support physical therapy of non-specific low back pain(Springer, 2010) Brodbeck, Dominique; Degen, Markus; Stanimirov, Michael; Kool, Jan; Scheermesser, Mandy; Oesch, Peter; Neuhaus, Cornelia; Fred, Ana; Filipe, Joaquim; Gamboa, HugoLow back pain is an important problem in industrialized countries. Two key factors limit the effectiveness of physiotherapy: low compliance of patients with repetitive movement exercises, and inadequate awareness of patients of their own posture. The Backtrainer system addresses these problems by real-time monitoring of the spine position, by providing a framework for most common physiotherapy exercises for the low back, and by providing feedback to patients in a motivating way. A minimal sensor configuration was identified as two inertial sensors that measure the orientation of the lower back at two points with three degrees of freedom. The software was designed as a flexible platform to experiment with different hardware, and with various feedback modalities. Basic exercises for two types of movements are provided: mobilizing and stabilizing. We developed visual feedback - abstract as well as in the form of a virtual reality game - and complemented the on-screen graphics with an ambient feedback device. The system was evaluated during five weeks in a rehabilitation clinic with 26 patients and 15 physiotherapists. Subjective satisfaction of subjects was good, and we interpret the results as encouraging indication for the adoption of such a therapy support system by both patients and therapists.04B - Beitrag KonferenzschriftPublikation A method and tool for strategic hospital planning(Springer, 2015) Brodbeck, Dominique; Degen, Markus; Walter, Andreas; Reichlin, Serge; Napierala, Christoph; Fred, Ana; Gamboa, Hugo; Elias, DirkWe developed a visualization tool and a methodology to support strategic planning of hospital service portfolios. Hospitals in Switzerland are reimbursed with a fixed fee per case. The fixed-fee model makes medical services comparable from a financial point of view. In order to take advantage of this model, the data that characterizes the medical services must be operationalized. The method that we developed, centers around a visual metaphor that provides the basis for strategic thinking. It is complemented by a visualization tool that allows visualization, analysis, and modification of service portfolios. Special features enable the tool to be used during live planning sessions. We describe the method, the tool, and its application in strategy workshops for infrastructure planning, reorganization, and resource optimization decisions.04B - Beitrag KonferenzschriftPublikation Limestone nanoparticles as nanopore templates in polymer membranes. Narrow pore size distribution and use as self-wetting dialysis membranes(Royal Society of Chemistry, 2014) Kellenberger, Christoph R.; Pfleiderer, Florian C.; Raso, Renzo; Burri, Cornelia H.; Schumacher, Christoph M.; Grass, Robert N.; Stark, Wendelin J.Limestone nanoparticles can be used as nanopore templates to prepare porous polymeric films. Their application as membranes is so far strongly limited by the fact that these films are highly hydrophobic. In this study, a simple method is reported to directly produce self-wetting membranes by the template removal method. Triethyl citrate modified polyethersulfone and cellulose acetate membranes were produced using dissolvable limestone nanoparticles as pore templates. The nanoporous polymer films were used as dialysis membranes and characterized by means of buffer exchange rate, molecular weight cut-off, protein adsorption, pore size distribution and water contact angle. The herein prepared membranes were further benchmarked against commercially available dialysis membranes with comparable average pore size. They showed narrow pore size distributions, fast dialysis rates at low protein adsorption and molecular weight cut-off of around 12 kDa. Interestingly, the triethyl citrate modified polyethersulfone membranes displayed only moderate change in pore size distribution as a result of the plasticizer additive compared to pure polyethersulfone membranes. This is a matter of substantial interest considering the fact that additive modifications of membranes produced by the predominant phase inversion process typically show alterations in morphology that lead to undesired changes in membrane performance. Furthermore, dextran recovery analysis proved to meet the specific requirements for dialysis membrane characterization and benchmarking.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Template-particle stabilized bicontinuous emulsion yielding controlled assembly of hierarchical high-flux filtration membranes(American Chemical Society, 2015) Hess, Samuel C.; Kohll, A. Xavier; Raso, Renzo; Schumacher, Christoph M.; Grass, Robert N.; Stark, Wendelin J.A novel solvent-evaporation-based process that exploits template-particle stabilized bicontinuous emulsions for the formation of previously unreached membrane morphologies is reported in this article. Porous membranes have a wide range of applications spanning from water filtration, pharmaceutical purification, and battery separators to scaffolds for tissue engineering. Different situations require different membrane morphologies including various pore sizes and pore gradients. However, most of the previously reported membrane preparation procedures are restricted to specific morphologies and morphology alterations require an extensive optimization process. The tertiary system presented in this article, which consists of a poly(ether sulfone)/dimethylacetamide (PES/DMAc) solution, glycerol, and ZnO-nanoparticles, allows simple and exact tuning of pore diameters ranging from sub-20 nm, up to 100 nm. At the same time, the pore size gradient is controlled from 0 up to 840%/μm yielding extreme asymmetry. In addition to structural analysis, water flux rates of over 5600 L m–2 h–1 are measured for membranes retaining 45 nm silica beads.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Regenerable cerium oxide based odor adsorber for indoor air purification from acidic volatile organic compounds(Elsevier, 2014) Raso, Renzo; Stepuk, A.; Mohn, D.; Paunescu, D.; Koehler, F.M.; Stark, W.J.Indoor odor management currently relies on energy-intensive high air exchange rates, or, more sustainable, on single use volatile organic compounds (VOC) adsorbers or ozonisation. This study investigates a more sustainable, multi-cycle use of an odor adsorber system that combines concepts from catalytic oxidation and air cleaning. Both pure and sodium doped, nanostructured CeO2 were tested as adsorber material for high volume removal of odorous compounds from air. As a representative compound for unpleasant odors, hexanoic acid (HA) was used. After air cleaning on fixed beds of CeO2 or Na/CeO2, both hexanoic acid loaded adsorber materials were heated under air and displayed considerable oxidation activity at 191 °C and 263 °C, respectively. Mass spectroscopy was used to confirm that no hexanoic acid desorbed during combustion. Cerium oxide showed an adsorber efficiency of ≥96.5% over a period of 60 h (Cin = 0.044 mg/L, gas hourly space velocity, GHSV = 440 h−1) and sodium doped cerium oxide adsorbed ≥97% for over 90 h (Cin = 0.056 mg/L, GHSV = 1100 h−1). CeO2 was regenerated at 220 °C in air and could be successfully re-used as adsorber without noticeable loss in performance. The study demonstrates that CeO2 has most promising properties for application as re-usable air cleaner due to its very good ability for adsorption even at highly dilute conditions (ppm-level) using a representative acidic test compound with rancid and sweaty odor. Sodium as a basic dopant further improved the adsorption of hexanoic acid but requires a higher regeneration temperature.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Indoor air purification using activated carbon adsorbers: Regeneration using catalytic combustion of intermediately stored VOC(American Chemical Society, 2014) Raso, Renzo; Zeltner, Martin; Stark, Wendelin J.In this study, we demonstrate a two-step process where activated carbon based air purifier systems can be regenerated in situ and eliminate volatile organic compounds (VOCs) from indoor air in an energy efficient way. A carbon based adsorber was combined in series with a CeO2/TiO2 oxidative catalyst for total oxidation of the previously adsorbed and periodically released volatile organic compounds during regeneration runs. We investigated the adsorption and desorption behavior of five different VOCs (diethyl ether, limonene, linalool, hexanoic acid, triethylamine and n-decane) with thermogravimetric measurements, mass spectrometry and elemental analysis. Cyclic loading and regeneration experiments were carried out with selected VOCs (limonene, linalool and n-decane) for testing regeneration at elevated temperature. We showed that in situ thermal regeneration and subsequent oxidation of released VOC is a sustainable and easy applicable technology for indoor air purification. This two-step approach allows energy saving as the VOCs are eliminated discontinuously (enriching VOCs; periodic catalytic combustion), and is of high environmental and economic interest, as much less maintenance services are required.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Physical mixtures of CeO2 and zeolites as regenerable indoor air purifiers. Adsorption and temperature dependent oxidation of VOC(Royal Society of Chemistry, 2014) Raso, Renzo; Stoessel, P. R.; Stark, W. J.Removal of volatile organic compounds (VOC) and indoor air quality regulation through adsorbers required exchange or maintenance of active materials. In this work, we combine well known VOC adsorbers with oxidation catalysts as intimate particulate mixtures. We demonstrate how typical VOC can subsequently adsorb on such mixed material fixed beds (usually days to weeks; the common state of the system, adsorption phase) using small organic compounds (diethyl ether, triethylamine), monoterpenes such as linalool and limonene, and hexanoic acid. Occasional regeneration runs through heat up of the fixed bed results in simultaneous desorption and oxidation of the accumulated VOC, thus regenerating full adsorption capacity for a next adsorption phase. We investigated both small pore zeolites (H-ZSM-5) and larger pore zeolites (13X) and found a distinct interplay between the pore size and the type of VOC. Thermogravimetry coupled with mass spectroscopy was used to quantitatively study the effects of mixing composition and temperature on adsorber performance and regeneration. The here investigated bi-functional systems combine very low maintenance costs and materials requirement with low air flow and exchange costs, thus suggesting mixed (two-functional) bed adsorbers with catalytic function as sustainable alternatives to currently used single use systems based on granulated zeolites or activated carbon. In this work we show the ability of zeolite/cerium oxide physical mixtures to adsorb and capture different classes of VOC at room temperature and release them for oxidation at higher temperatures in a regenerative and sustainable process.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Fibers mechanically similar to sheep wool obtained by wet spinning of gelatin and optional plasticizers(Wiley, 2014) Stoessel, Philipp R.; Raso, Renzo; Kaufmann, Tim; Grass, Robert N.; Stark, Wendelin J.AbstractGelatin is an exceptional and versatile biopolymer with applications in various industries. As the most abundant structural protein in vertebrates it is available in megaton quantities. On these grounds, it would be a plausible substitute for synthetic polymers. Gelatin processing into fibers seems promising as continuous protein filaments do not have the limitation of natural fibers, i.e., small staple fiber length. Instead of spinning an aqueous gelatin solution, a protein precipitate from a phase‐separated system is used. Robust wet spinning with subsequent fiber drawing allows production of a gelatin filament with similar mechanical properties as sheep wool. Different degrees of fiber drawing and addition of plasticizers enable to tailor the mechanical and thermal fiber properties and demonstrate the versatility of the proposed spinning process.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Magnetic superbasic proton sponges are readily removed and permit direct product isolation(American Chemical Society, 2014) Schneider, Elia M.; Raso, Renzo; Hofer, Corinne J.; Zeltner, Martin; Stettler, Robert D.; Hess, Samuel C.; Grass, Robert N.; Stark, Wendelin J.Workup in organic synthesis can be very time-consuming, particularly when using reagents with both a solubility similar to that of the desired products and a tendency not to crystallize. In this respect, reactions involving organic bases would strongly benefit from a tremendously simplified separation process. Therefore, we synthesized a derivative of the superbasic proton sponge 1,8-bis(dimethylamino)naphthalene (DMAN) and covalently linked it to the strongest currently available nanomagnets based on carbon-coated cobalt metal nanoparticles. The immobilized magnetic superbase reagent was tested in Knoevenagel- and Claisen-Schmidt-type condensations and showed conversions of up to 99%. High yields of up to 97% isolated product could be obtained by simple recrystallization without using column chromatography. Recycling the catalyst was simple and fast with an insignificant decrease in catalytic activity.01A - Beitrag in wissenschaftlicher Zeitschrift