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Now showing items 1721-1730 of 1730
Aufsatz
Climatic Ageing of Components of Polymer Based Electrochromic Devices
(2013-09-09)
Combining a shading function and a polycarbonate window displays an attractive alternative to the currently employed glass roof in vehicles. However, the ageing of such a device must be investigated before any application. Therefore, our investigations focus on the ageing of the components of a polycarbonate based electrochromic device. The optical, electrical, mechanical and electrochemical properties of the ion storage layer as well as the substrate will be assessed after storage in a climate with a high humidity ...
Aufsatz
UV Surface Treatment of Polycarbonate for Adhesion Improvement to Liquid Silicone Rubber (LSR)
(2018)
The adhesion of self-adhesive liquid silicone rubbers to thermoplasts is only possible for a few selected material combinations without a surface pretreatment. A UV pretreatment is effective for polycarbonate and short irradiation periods are sufficient. To clarify the required irradiation conditions that result in an improvement of adhesion, the varying irradiation conditions were assessed. FTIR-ATR spectroscopy was used for surface analysis to characterize the change in the polymer surface.
Dissertation
Wie können sich die Freiburger Quartiere generationengerecht weiterentwickeln?
(2016)
Wie können sich Freiburger Quartiere weiterentwickeln und dabei die Wohn- und Lebens-bedürfnisse aller Generationen berücksichtigen? Die vorliegende stadtplanerische Studie befasst sich mit den Chancen und Herausforderungen einer Universitätsstadt, die durch ihr Angebot an Ausbildungsmöglichkeiten in Verbindung mit einer hohen Lebens- und Freizeit-qualität viele junge Menschen anzieht. Gleichzeitig und kaum beachtet, gibt es auch in die-ser Stadt eine Alterung, die es in den vorherigen Generationen in diesem Umfang ...
Aufsatz
Spatio-temporal resolution studies on a highly compact ultrafast electron diffractometer
(2015)
Time-resolved diffraction with femtosecond electron pulses has become a promising technique to directly provide insights into photo induced primary dynamics at the atomic level in molecules and solids. Ultrashort pulse duration as well as extensive spatial coherence are desired, however, space charge effects complicate the bunching of multiple electrons in a single pulse.Weexperimentally investigate the interplay between spatial and temporal aspects of resolution limits in ultrafast electron diffraction (UED) on our ...
Verschiedenartige Texte
Greece: Austerity's unexpected allies
(2018-04)
Contrary to pre-electoral proclamations and the recent optimism of the government and its European allies, the situation since 2015 has only gotten worse. Pensions have been cut twice more (with additional cuts promised in future). More than 1 million Greeks have already suffered some form of appropriation due to debt, with another 1.7 million waiting in line - a number that represents only 70% of those indebted to the tax office. One in three face material and social deprivation (Eurostat, 2016), placing Greece third ...
Aufsatz
Characterization of wood-based multi-material systems under dynamic impact stress
(2018)
Due to its naturally grown properties, wood has played a rather subordinate role as a material for technical applications up to now. In this paper, multi-material systems based on veneers of beech (Fagus sylvatica) with different reinforcing variants were investigated. In addition to the influence of different adhesive systems (urea formaldehyde and polyurethane), the effect of reinforcing by aramid fiber fabric and stainless steel foil in different climates was examined. At the center of the investigations were ...
Aufsatz
Wood-Polypropylene Composites: Influence of Processing on the Particle Shape and Size in Correlation with the Mechanical Properties Using Dynamic Image Analysis
(2018-11-16)
The particle size and shape are of momentous significance for the mechanical properties of plastic composites. However, natural fillers, like wood, are not consistent in these attributes. In order to investigate the shared traits between these characteristics, WPCs were produced using polypropylene, hardwood and softwood fillers with different particle sizes and a coupling agent. Afterwards, specimens were processed using an injection molding machine. The filler sizes and shapes were measured using dynamic image ...
Aufsatz
Investigations on Tightness of Polymer-Metal Hybrids in Environments with Thermal, Media, and Mechanical Loads
(2017-07-31)
With polymer-metal hybrids becoming more commonly used as structural components it was investigated how they perform in complex environments with combined thermal, media, and mechanical loads. Special attention was put on media tightness under said loads. This paper sums up the activities of the polymer technology research group of the University of Kassel on hybrids produced by overmolding metal inserts. Investigations concerning joint strength and influence of (cyclic) temperature loads and chemical corrosion on ...
Aufsatz
Cross-Linked Hydrophobic Starch Granules in Blends with PLA
(2018-04-17)
The majority of native starch is used in the food sector and in the paper industry. Only a small amount is used in polymer engineering. One reason for the reluctance of the plastics processing industry to use starch as a filling material in polymer blends is the unsatisfactory mechanical behavior of starch when combined with thermoplastics. Another reason is the hydrophilicity of starch. In order to make these materials capable of competing, an amelioration of the mechanical properties is compulsory. By means of ...
Aufsatz
Mechanical Properties of Polydimethylsiloxane as a Function of the Amount and Type of Crosslinking Agent
(2017-06-13)
In this investigation, a high-consistency rubber (HCR) was mixed with five different, typically used crosslinking agents that are based on organic peroxide. Furthermore, the amount of crosslinking agent was varied in order to quantify the effect on the mechanical properties. All materials were processed in a hot pressing process, and, subsequently, post-cured. The properties were characterized by the measurement of the swelling ratio, shore A-hardness, rebound resilience and tensile test. We successfully proved that ...