Ostwestfalen-Lippe University of Applied Sciences and Arts
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Correlation between wear and fatigue properties and the lifetime of silver coated electrical connectors
No full textIn a previous paper, the correlation between the wear resistance of coatings and the lifetime of electrical connectors under fretting load was discovered. Based on this knowledge, various modifications of silver-based coatings with markedly increased wear resistance have been developed, and a calculation model for predicting connector lifetime has been formulated. Investigations on silver-coated electrical contacts with increased wear resistance show extended lifetimes in fretting wear and fretting corrosion tests, and the calculation model with various modified coating materials can be validated. However, contacts with very high wear-resistant coatings fail earlier than the specific wear coefficient and the calculation model prediction suggest.
The in-depth investigation of the coating material and the wear scar revealed the reasons for this unexpectedly shorter lifetime. The high wear resistance of modified silver coatings is achieved by increased micro-hardness. Both coatings with coating materials of high hardness and high thickness can lead to longer lifetimes under fretting load. However, increased fretting cycles can also cause fatigue and electrical contacts can fail due to delamination of the surface coating caused by fretting fatigue, and this delamination can lead to a sudden exposure of the base material, thus enabling its corrosion.
Therefore, both wear resistance and fatigue resistance should be increased in order to achieve a long lifetime of electrical contacts under fretting load
Lebendige Skizzen: Storyboards in Animation und Film
No full textDie Arbeit widmet sich dem Einsatz von Storyboards in Live-Action und Animation. Sie befasst sich mit dem Aufbau und der Erstellung des Storyboards und erforscht, welche Priorisierung es in verschiedenen Filmgenres bedarf.
Der theoretische Teil behandelt den Aufbau eines Storyboards und die Materialien, die für die Umsetzung benötigt werden. Anhand von Beispielen werden Unterschiede zwischen verschiedenen Filmgattungen erforscht, um herauszustellen, welche Details genrespezifisch benötigt werden.
Im praktischen Teil wird anhand der digitalen Erstellung eines Storyboards die Produktion für einen Kurzfilm veranschaulicht. Die Anfertigung findet in mehreren Iterationen statt, die nach Gesprächen zwischen Regie und Storyboardartist erstellt werden
Allulose as novel ingredient for improving freshness of yeast-made bakery products
No full textGerman consumers have high expectations for the freshness of bakery products. When products like burger buns or toast are not sufficiently soft, significant food waste results. In traditional recipes, sucrose plays several important roles, including extending the shelf life of bread, but it also adds undesirable calories. Allulose is a promising sugar alternative with several technological advantages, such as enhanced browning and improved freshness. This study investigated the effect of allulose on the freshness of yeast-based bakery products compared to sucrose and fructose. Regardless of grain type or flour, the use of allulose led to earlier starch gelatinization, which slowed down starch retrogradation. Storage tests of burger buns at 20 °C and 4 °C showed that buns made with allulose had a softer crumb, higher moisture content, and lower water activity (aw-value) over the entire storage period. The improved freshness was also confirmed by descriptive sensory analysis. These results suggest that using allulose can enhance the freshness of yeast-based bakery products and help reduce food waste caused by excessively dry crumbs. Allulose not only improves texture but also contributes to reducing the environmental impact of food waste by prolonging product freshness
THz Characterization of Inkjet Printable Polymers
No full textAdditive manufacturing (AM) of terahertz (THz) components is a cost-effective and efficient method of rapid prototyping. This work discusses the THz characterization of AM-compatible polymers to evaluate their potential use in the fabrication of THz components. The materials under investigation are primarily used in the inkjet 3D-printing (IP) process, and are compared with other AM-compatible materials [1]. The authors analyzed heat resistant AR-H1 material, transparent AR-M2 material and flexible silicon elastomer material. After the THz time domain spectroscopy of these materials, it can be deduced that the materials AR-M2 and AR-H1 can be used in manufacturing of THz components, with the benefit of a superior printing resolution of 50 µm.
[1] A. Shrotri, A. K. Mukherjee, S. Lohöfener, A. Springer, O. Stübbe and S. Preu, "Additive manufacturing and characterization of hollow core metal and topas waveguides for Terahertz sensor systems," 2023 48th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), Montreal, QC,
Canada, 2023, pp. 1-2, doi: 10.1109/IRMMW-THz57677.2023.10299134
Aufbau einer erfolgreichen Selbstständigkeit in der Hochzeitspapeterie auf der Verkaufsplattform Etsy
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An iterative process and mixture design approach for dry granulated ternary blends of filler-binders
No full textRoller compaction/dry granulation (RC/DG) is a key process in pharmaceutical manufacturing for improving powder flowability, density, and segregation resistance. Advanced statistical modeling was used to optimize RC/DG process parameters and subsequently binder compositions by employing process and mixture design experiments. The authors used microcrystalline cellulose (MCC), silicified MCC (SMCC), and dicalcium phosphate (DCP) as filler-binder examples in RC/DG experiments. Granule and tablet properties, including flowability, bulk and tapped densities, as well as resistance to crushing, were analyzed using compendial methods. The process design experiments confirmed that RC/DG reduces manufacturability compared to direct compression. Optimal processing conditions, balancing sufficient tablet strengths and granule formation, were identified to be between 20 (SCF * ϑ) [kN/cm] and ∼ 60 (SCF * ϑ) [kN/cm]. Thereby (ϑ) is defined as the screw-to-roll speed ratio and (SFC) as the specific compaction force. Mixture design experiments revealed optimal mixtures balancing SMCC, MCC, and DCP to achieve desired properties like low angle of repose, high bulk density, and strong tablets. These findings provide guidance for selecting formulations and process parameters in RC/DG applications. The derived ‘SCF * ϑ’- factor was found to effectively describe the granulation intensity. A superimposed mixture design model based on precise target values of the parameters bulk density, flow properties, and breaking force allowed identification of the best formulation
Revealing the aging mechanisms of solketal, oxymethylene ether, and mixtures thereof as promising e-fuels
No full textSolketal and oxymethylene ether (OME) are two promising blending candidates for regenerative fuels (e-fuels), which could contribute to a holistic solution to the energy crisis. In this study the thermo-oxidative aging of these two e-fuels in their pure form as well as in binary mixtures with different ratios (3:1, 1:1, and 1:3) (vol%) is investigated. Herein, the reaction networks of the thermo-oxidative aging process of both e-fuels and mixtures thereof is elucidated based on intermediates and decomposition products determined via GC-MS. Furthermore, changes of important fuel-specific parameters like kinematic viscosity and density as well as total acid number during aging have been determined. The 3:1 solketal:OME (vol%) mixture exhibits a higher stability to thermo-oxidative aging than the pure fuel components or mixtures with other ratios. The viscosity value of this mixture is within the DIN EN 590 norm after accelerated aging of 72 h (viscosity (72 h) = 4.25 mm(2)/s)) unlike other blends. The maximum value of the total acid number of this aged mixture reaches only similar to 29 % of the maximum value of aged pure OME and has the lowest value of all mixtures. Furthermore, the formation of a precipitate could be successfully suppressed in the 3:1 solketal:OME (vol%) mixture different from other mixtures. With these findings, this study contributes to the design of new sustainable fuels for the transport sector