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- ItemDevelopment of joining methods for highly filled Graphite/PP composite based bipolar plates for fuel cells: Adhesive joining and welding(Melville, NY : AIP, 2019) Rzeczkowski, P.; Lucia, M.; Müller, A.; Facklam, M.; Cohnen, A.; Schäfer, P.; Hopmann, C.; Hickmann, T.; Pötschke, Petra; Krause, BeateNovel material solutions for bipolar plates in fuel cells require adapted ways of joining and sealing technologies. Safe and life time enduring leak-tight contacts must be achieved by automatic processes using reasonable joint forces. A proper sealing should manage such challenges as good ageing properties, excellent leaktightness, high thermal conductivity and low gas permeability. Hence in this work, adhesive bonding and welding are considered as suitable methods, which can fulfill the requirements mentioned above. Adhesive systems seem to be more easy to apply than conventional sealing (hand layed-up rubber gaskets), e.g. with automatic dispensers. Additionally, the properties of an adhesive joint can be enhanced by a process-specific surface pre-treatment. This work focuses on the characterization of adhesive systems and their joints with highly filled graphite composites. Mechanical properties of the joints were characterized through lap-shear tests. The influence of ageing caused by humidity or acidic solvent at increased temperature on the bond line properties as well as neat adhesive was examined. The thermal conductivities of neat adhesives and through the entire joint were examined. In order to improve above conductivities, roughening, substrate pre-heating, post-curing and various contact pressure weights were applied. Plasma treatment was chosen as surface pre-treatment method for improving substrate's surface energy. An alternative to bonding is plastic welding, which does not require the use of sealants and adhesives. Based on former study of influences of filler content on the welding process using ultrasonic, hot plate or infrared welding, a welding method for joining the graphite compounds was derived.
- ItemComparison of the molecular properties and morphology of polypropylenes irradiated under different atmospheres and after annealing(Hoboken, NJ [u.a.] : Wiley InterScience, 2006) Krause, Beate; Häußler, Liane; Voigt, DieterElectron-beam irradiation, a well-known way of generating long-chain branching, was used to modify polypropylene. Samples were investigated with differential scanning calorimetry, polarized light microscopy, and size exclusion chromatography. Independently of the atmosphere, postannealing led to the deactivation of residual radicals and to the reduction of the nucleus density. In comparison with the initial polypropylene, the crystallization temperatures increased for nonannealed samples but decreased for annealed samples. Stable products were obtained only by irradiation in nitrogen followed by annealing. A reaction including free radicals with oxygen in the ambient atmosphere led to increasing molar mass degradation and the formation of long-chain branching after Storage. © 2006 Wiley Periodicals, Inc.
- ItemEffect of Ge-doping on the short-wave, mid- and far-infrared intersubband transitions in GaN/AlGaN heterostructures(Bristol : IOP, 2017) Lim, Carolin B.; Ajay, Akhil; Lähnemann, Jonas; Bougerol, Catherine; Monroy, EvaThis paper assesses the effects of Ge-doping on the structural and optical (band-to-band and intersubband (ISB)) properties of GaN/AlGaN multi-quantum wells (QWs) designed to display ISB absorption in the short-wave, mid- and far-infrared ranges (SWIR, MIR, and FIR, respectively). The standard c-plane crystallographic orientation is considered for wells absorbing in the SWIR and MIR spectral regions, whereas the FIR structures are grown along the nonpolar m-axis. In all cases, we compare the characteristics of Ge-doped and Si-doped samples with the same design and various doping levels. The use of Ge appears to improve the mosaicity of the highly lattice-mismatched GaN/AlN heterostructures. However, when reducing the lattice mismatch, the mosaicity is rather determined by the substrate and does not show any dependence on the dopant nature or concentration. From the optical point of view, by increasing the dopant density, we observe a blueshift of the photoluminescence in polar samples due to the screening of the internal electric field by free carriers. In the ISB absorption, on the other hand, there is a systematic improvement of the linewidth when using Ge as a dopant for high doping levels, whatever the spectral region under consideration (i.e. different QW size, barrier composition and crystallographic orientation).
- ItemElectrical and thermal conductivity of polypropylene filled with combinations of carbon fillers(Melville, NY : AIP, 2016) Krause, Beate; Pötschke, PetraThe thermal and electrical conductivity of polymer composites filled with a low content up to 7.5 vol% of different carbon fillers (carbon nanotubes, carbon fibers, graphite nanoplates) were investigated. It was found that the combination of two or three carbon fillers leads to an increase of thermal conductivity up to 193% which is higher than the sum of the effects of both fillers.
- ItemA Data-Driven Approach for Analyzing Healthcare Services Extracted from Clinical Records(Piscataway, NJ : IEEE, 2020) Scurti, Manuel; Menasalvas-Ruiz, Ernestina; Vidal, Maria-Esther; Torrente, Maria; Vogiatzis, Dimitrios; Paliouras, George; Provencio, Mariano; Rodríguez-González, Alejandro; Seco de Herrera, Alba García; Rodríguez González, Alejandro; Santosh, K.C.; Temesgen, Zelalem; Soda, PaoloCancer remains one of the major public health challenges worldwide. After cardiovascular diseases, cancer is one of the first causes of death and morbidity in Europe, with more than 4 million new cases and 1.9 million deaths per year. The suboptimal management of cancer patients during treatment and subsequent follows up are major obstacles in achieving better outcomes of the patients and especially regarding cost and quality of life In this paper, we present an initial data-driven approach to analyze the resources and services that are used more frequently by lung-cancer patients with the aim of identifying where the care process can be improved by paying a special attention on services before diagnosis to being able to identify possible lung-cancer patients before they are diagnosed and by reducing the length of stay in the hospital. Our approach has been built by analyzing the clinical notes of those oncological patients to extract this information and their relationships with other variables of the patient. Although the approach shown in this manuscript is very preliminary, it shows that quite interesting outcomes can be derived from further analysis. © 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
- ItemOberflächenmorphologie von Arzneistoffpartikeln - Ein optisch evaluierbares Kriterium für die Auflösungsgeschwindigkeit(München : Elsevier, Urban & Fischer , 2002) Diebold, Steffen M.Für die Auflösungsgeschwindigkeit von schwer wasserlöslichen Arzneistoffpartikeln spielt die Hydrodynamik an den Partikel-Oberflächen eine große Rolle. Diese ist ihrerseits beeinflußt von der Geometrie und der Oberflächenmorphologie der Partikel. In dieser Arbeit wurde gezeigt, dass sich zur Charakterisierung dieser Parameter die Rasterelektronenmikroskopie (SEM) auch für die Untersuchung von Arzneistoffen gut eignet. Am Beispiel von Felodipin-Kristallen wurde nachgewiesen, dass reale Arzneistoffpulver auch an scheinbar „glatten“ Oberflächen Protrusionen, Kanten und Kavitäten aufweisen. Deren Größenordnungen lassen sich mit Hilfe der Elektronenmikroskopie abschätzen. Die Oberflächenmorphologie von Arzneistoffpartikeln ist ein Kriterium für die Auflösungsgeschwindigkeit oral verabreichter Arzneistoffe. Die Rasterelektronenmikroskopie leistet dabei wertvolle Dienste zur Charakterisierung der Oberflächen von Arzneistoffpartikeln.
- ItemA successful approach to disperse MWCNTs in polyethylene by melt mixing using polyethylene glycol as additive(Oxford : Elsevier Science, 2012) Müller, Michael Thomas; Krause, Beate; Pötschke, PetraAn additive-assisted one-step melt mixing approach was developed to produce nanocomposites based on linear low density polyethylene (LLDPE) with multiwalled carbon nanotube (MWCNT). The polymer granules, nanotube powder (2 wt% Nanocyl™ NC7000) and 1-10 wt% of the non-ionic additives poly(ethylene glycol) (PEG) or poly(ethylene oxide) (PEO) with molar masses between 100 g/mol and 100,000 g/mol were simply fed together in the hopper of a small-scale DSM Xplore 15 twin-screw microcompounder. The produced MWCNT/LLDPE composites showed excellent MWCNT dispersion and highly improved electrical properties as compared to samples without the additive, whereas the effects depend on the amount and molar mass of the additive. When 7 wt% PEG (2000 g/mol) were used, a reduction of the electrical percolation threshold from 2.5 wt% to 1.5 wt% was achieved. © 2012 Elsevier Ltd. All rights reserved.
- ItemProdukthaftung in der Apotheke(Stuttgart : Deutscher Apotheker Verlag, 2005) Diebold, Steffen M.Stellt ein Apotheker Arzneimittel, Medizinprodukte oder andere apothekenübliche Waren (z.B. Kosmetika oder Mixturen nach Angaben von Heilpraktikern, Homöopathen oder Anthroposophen) in seiner Offizin selbst her, so haftet er (grundsätzlich) einem dadurch ggf. geschädigten Kunden (auch) nach den Vorschriften des Produkthaftungsgesetzes. Diese Haftung besteht unabhängig vom eigenen Verschulden. Sie greift auch bei der Einfuhr von Arzneimitteln aus Staaten, die nicht zum Europäischen Wirtschaftsraum gehören, sowie bei Import und Abgabe von aus Drittländern eingeführten und im Geltungsbereich des Arzneimittelgesetzes (AMG) nicht zugelassenen Fertigarzneimitteln nach § 73 (3) AMG.
- ItemElectrical and melt rheological characterization of PC and co-continuous PC/SAN blends filled with CNTs: Relationship between melt-mixing parameters, filler dispersion, and filler aspect ratio(Hoboken, NJ [u.a.] : Wiley, 2018) Liebscher, Marco; Domurath, Jan; Krause, Beate; Saphiannikova, Marina; Heinrich, Gert; Pötschke, PetraElectrical and melt rheological properties of melt-mixed polycarbonate (PC) and co-continuous PC/poly(styrene–acrylonitrile) (SAN) blends with carbon nanotubes (CNTs) are investigated. Using two sets of mixing parameters, different states of filler dispersion are obtained. With increasing CNT dispersion, an increase in electrical resistivity near the percolation threshold of PC–CNT composites and (PC + CNT)/SAN blends is observed. This suggests that the higher mixing energies required for better dispersion also result in a more severe reduction of the CNT aspect ratio; this effect was proven by CNT length measurements. Melt rheological studies show higher reinforcing effects for composites with worse dispersion. The Eilers equation, describing the melt viscosity as function of filler content, was used to fit the data and to obtain information about an apparent aspect ratio change, which was in accordance with measured CNT length reduction. Such fitting could be also transferred to the blends and serves for a qualitatively based discussion. © 2017 Wiley Periodicals
- ItemA Fair and Comprehensive Comparison of Multimodal Tweet Sentiment Analysis Methods(Ithaka : Cornell University, 2021) Cheema, Gullal S.; Hakimov, Sherzod; Müller-Budack, Eric; Ewerth, RalphOpinion and sentiment analysis is a vital task to characterize subjective information in social media posts. In this paper, we present a comprehensive experimental evaluation and comparison with six state-of-the-art methods, from which we have re-implemented one of them. In addition, we investigate different textual and visual feature embeddings that cover different aspects of the content, as well as the recently introduced multimodal CLIP embeddings. Experimental results are presented for two different publicly available benchmark datasets of tweets and corresponding images. In contrast to the evaluation methodology of previous work, we introduce a reproducible and fair evaluation scheme to make results comparable. Finally, we conduct an error analysis to outline the limitations of the methods and possibilities for the future work.