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This paper presents an analytical method for determining the bending stresses and deformations in prismatic, noncircular profile shafts with trochoidal cross sections. The so-called higher trochoids can be used as form-fit shaft-hub connections. Hybrid (mixed) higher trochoids (M-profiles) were developed for the special application as a profile contour for the form-fit shaft and hub connections in an earlier work by the author. M-profiles combine the advantages of the two standardised polygonal and spline contours, which are used as shaft-hub connections for the transmission of high torques. In this study, the geometric and mechanical properties of the higher hybrid trochoids were investigated using complex functions to simplify the calculations. The pure bending stress and shaft deflection were determined for M-profiles using bending theory based on the theory of mathematical elasticity. The loading cases consisted of static and rotating bends. Analytical, numerical, and experimental results agreed well. The calculation formulas developed in this work enable reliable and low-cost dimensioning with regard to the stresses and elastic deformations of profile shafts subjected to bending loads.
Hypotrochoidal profile contours have been produced in industrial applications in recent years using two-spindle processes, and they are considered effective high-quality solutions for form-fit shaft and hub connections. This study mainly concerns analytical approaches to determine the stresses and deformations in hypotrochoidal profile shafts due to pure bending loads. The formulation was developed according to bending principles using the mathematical theory of elasticity and conformal mappings. The loading was further used to investigate the rotating bending behaviour. The stress factors for the classical calculation of maximum bending stresses were also determined for all those profiles presented and compiled in the German standard DIN3689-1 for practical applications. The results were also compared with the corresponding numerical and experimental results, and very good agreement was observed. Additionally, based on previous work, the stress factor was determined for the case of torsional loading to calculate the maximum torsional stresses in the standardised profiles, and the results are listed in a table. This study contributes to the further refinement of the current DIN3689 standard.
Boron-doped diamond (BDD) electrodes offer some excellent electrochemical properties, including the widest potential window in aqueous solutions, low background currents and good chemical and mechanical stability. They can also be produced transparent and could offer a great potential for spectroelectrochemical (SEC) experiments. However, to reach the mentioned electrical properties for such optically transparent electrodes (OTE), heavy doping is needed to increase conductivity. The introduction of boron in return reduces the transparency significantly. This work investigates the effect of introducing an alternative path for electrons in the form of an highly conductive get transparent interlayer which could increase the conductivity without increasing the BDD film or the doping level supporting high transparency in the visible (Vis) and ultraviolet (UV) regime. This work furthermore investigates possible interlayers for this application and implements four of them in two BDD OTE samples which are extensively studied by electrical, optical and electrochemical methods. An ultra-thin metal film (UTMF) of titanium (Ti) is shown to decrease the electrochemical resistance by 2.4kOhms while decreasing the transparency of a BDD OTE by only 11%.
China is planning to rebuild the ancient Silk Road into a modern infrastructre network, spanning Asia, Central Asia and Europe. The investements are high and are not paying off. This thesis is exploring the political reasons for China's plans and the impact the initiative has on the Chinese-Kazakh relationship.
Autonomous Vehicles (AVs) as a means of public transportation is set to revolutionize the mobility behavior of elderly people in the coming future. Though the vehicle manufacturers and corporates emphasize on potential benefits of AVs to elderly citizens, very little has been researched and studied about this large cohort (age 65+) in society. This study aims to measure the experience of the elderlies in this Highly Automat Shuttle (HAS) in Berlin and find out the potential pros and cons affecting the design, trust and security, and perception to adopt this technology in the future. Among the elderly respondents surveyed, 93% found the HAS convenient, with minor design issues addressed. Respondents (90%) were willing to use it for their first and last-mile journey and considered that the HAS would help improve the social participation of elderlies with mobility restrictions. However, elderlies still have trust issues integrating a fully driverless vehicle in the domain of public transportation. The significant findings on the difference in the experience of HAS between the elderlies, adults, and younger adults could be adopted to develop the design further, making it more comfortable and trustworthy towards the elderly population.
Die Diplomarbeit umfasst die Analyse der für den Prüfstand notwendigen Geräte, den Aufbau des Prüfstandes und die Programmierung von kundenspezifischen Applikationen mittels LabVIEW.