Refine
Year of publication
Document type
- Contribution to a Periodical (94) (remove)
Language
- English (94) (remove)
Keywords
- Apache Kafka (2)
- Machine learning (2)
- Simulation (2)
- Smart home (2)
- Stream processing (2)
- API (1)
- Actinometry (1)
- Advanced oxidation processes (AOPs) (1)
- Alveolar recruitment (1)
- Ambient assisted living (1)
Course of studies
TSE-Signatur Verifier
(2022)
Diese wissenschaftliche Publikation befasst sich mit dem Aufbau und der Funktionsweise der alternativen
Antriebstechnologie Wasserstoffverbrennungsmotor. Es wird das
Potential dieses Motors hinsichtlich der Klimaziele als Antrieb für PKW und schwere Nutzfahrzeuge untersucht. Dazu wird dieser bezüglich des Wirkungsgrads und der CO2-Bilanz mit den herkömmlichen Antrieben Otto- und Dieselmotor sowie den
weiteren alternativen Antrieben Batterie und Brennstoffzelle
verglichen.
Injury to the anterior and posterior cruciate ligaments is not an uncommon occurrence. A rapid movement can already cause such an injury. Reconstruction of the anterior and posterior cruciate ligaments (ACL/PCL) in the knee joint is a complex orthopedic challenge. In this context, the development of a graft preparation system is gaining importance. Such a system will help surgeons prepare grafts accurately and efficiently to optimize reconstruction processes. This can increase the accuracy of graft placement, reduce surgical times, and decrease recovery time and postoperative risk for patients.
This paper focuses on the development of a graft preparation system for ACL/PCL reconstruction in collaboration with Getsch+Hiller Medizintechnik. The challenges and requirements in developing such a system were analyzed to ensure functionality and effectiveness. Existing approaches and technologies were examined to identify potential improvements and innovations. Development included extensive research on ACL/PCL reconstruction using grafts, including various surgical techniques. A detailed analysis of the graft preparation process was performed to identify critical issues. The design of the graft preparation system is based on research data and is performed using CAD. The needs of the target group, customer requirements and findings from research were considered.
Challenges when Designing LED-Based Illumination Systems in Medical Applications and Diagnostics
(2017)
Entwurf und Implementierung einer kamerabasierten Anwendung für ein Mühlespiel für den Panda-Roboter
(2023)
Optogenetics and optogenetic systems cover a wide range of applications in the research of neurological pathways. In this overview, relevant aspects regarding the development of optogenetic systems should be shown. These are the optogenetic systems – opsins and optical switches – as well as optoprobes, materials, application areas and limitations of these applications. Additionally, a short outlook should be given. No detailed analysis for specific optogenetic systems or their partial aspects were carried out.
For thin zinc sheets for construction purposes different welding techniques like tungsten inert gas (TIG), plasma arc (PAW) or micro-friction stir (μFSW) welding can be used. However, low ultimate tensile strength (UTS) often leads
to cracking in the weld even at low loads. The characteristics of laser welding make it particularly suitable for joining thin sheets and low-melting materials. Nevertheless, little is known about the weldability of thin zinc sheets by laser welding and the effects of the basic process parameters of laser power and travel speed on the welding process and the UTS of the weld. In this study,
thin zinc sheets were welded at different laser powers and travel speeds. Tensile testing of the welded joint showed, that the UTS and elongation at break increase with the energy input per unit length, but the welding process became gradually unstable and the susceptibility for welding defects increased. This leaves only a few laser powers and travel speeds that produce good welds with respect to UTS and elongation at break. Under these conditions laser welding is an alternative processing technique to
TIG, PAW and μFSW, but needs further investigation to
improve its stability. To implement laser welding in highly
automated production processes further research is required on laser welding of rolled zinc alloys.
A physically inspired model of Dip d792 and d1519 of the Kepler light curve seen at KIC8462852
(2016)
The paper shows the influence of low-pressure plasma on polyethylene terephthalate (PET) to achieve improved layer adhesion between PET and ALD multilayers. The literature describes a relationship between functional groups that are incorporated into the polymer surface and better layer adhesion. In this work, the relative number of functional groups after treatment on the surface of PET was measured by the surface energy.
The PET film Hostaphan® RNK was exposed to oxygen and argon plasma with varying treatment times. Subsequently, the surface energy was determined via the contact angle measurement.
The investigations have shown that with increasing treatment time in the oxygen plasma, an increasing surface energy is associated, which is due to the increased incorporation of functional groups, such as hydroxy groups. Furthermore, the results have confirmed the thesis that if the plasma treatment is too long, oxidation takes place on the polymer surface and thus the surface energy decreases. Another aspect that has emerged in the results of the study is the subordinate role of the power of the plasma.
Since the study has not proven the connection between a good layer adhesion, of ALD multilayers on PET, and a high surface energy, this work should serve as an indication for the investigation of this thesis.
Testing applications for SmartHome environments is quite complicated, since a real environment is not accessible or the conditions are not controllable during development time. The need to set up the whole hardware environment, increase the complexity of these systems enormously. Therefore, it is helpful to simulate the SmartHome hardware components and environment conditions (e.g. rain, heat, etc.). This paper contains an approach to improve the test and demonstration process of Internet of Things scenarios. A prototype (ScnSim: Scenario Simulator) was developed to set up scenarios. The user of the ScnSim can create her/his own scenario using items (sensors/actuators) and rules, which control the sensors and actors building the IoT enviornment. This simulator is supposed to support the user testing IoT applications or configurations of SmartHome platforms like openHAB. In addition, the ScnSim is supposed to help demonstrating showcases, for example, often demonstrated on a trade fair or as a proof of concept for a customer.
Water Worries : As the climate changes, scientists study how droughts affect our inland waters
(2022)
Requirements of Health Data Management Systems for Biomedical Care and Research: Scoping Review
(2020)
Rapid Phospho-Turnover by Receptor Tyrosine Kinases Impacts Downstream Signaling and Drug Binding
(2011)
In this work, the comparability of the cooling effect of two Peltier elements from different manufacturers is investigated for cooling the reagent module of a chemiluminescence analyzer. The temperature inside the reagent module is measured and evaluated at several positions. In this study, two different types of verification tests are performed under extreme climatic conditions. On the one hand, in a specific functional “cold start test”, the temperature in the reagent module is measured and evaluated to determine whether the measured temperatures are within the specified temperature range after the specified time. In addition, the performance of the Peltier elements is also evaluated. On the other hand, as an unspecific regression stress test, a “smoke test” is performed that is mainly designed to allow identifying unpredictable events. While processing a long and
complex work list, any deviant system behavior can be detected. Again, the temperature inside the reagent module should not exceed the specified temperature range.
A major problem in the automotive sector is dealing with used hydraulic oil. Since this oil loses its purity over time, it must be changed. In most cases, the condition of the oil is not really checked, but is changed after a certain number of kilometers. It is possible that intact hydraulic oil is wasted in the process. Until now, there is no cost-effective method to check the purity on hydraulic oils, so there is nothing left but to remove all of the oil. The purpose of this work is to develop a measuring station for a MEMS-based oil quality sensor. With the help of the oil quality sensor, deviations of aged hydraulic oils shall be investigated. An infrared light source and a Fabri-Perot spectrum sensor will be used for more accurate detection of deviations in aged hydraulic oil. The goal is to clarify whether it is possible to use wavelength spectra to detect differences in aged hydraulic oil. To do this, a suitable Fabri-Perot spectrum sensor and a light source with the appropriate wavelength range were carefully selected. Furthermore, a measurement setup for static measurements was worked out. Subsequently, measurements were carried out with and without hydraulic oil and the measured data was compared with reference data. Finally, differences in the aged hydraulic oil could be determined by means of light wave measurements.
Parylene-C is a multifunctional polymer coating in the coating industry. In medical technology, it is approved for implants due to its biocompatibility. For example, it is used as a coating for electronic components and parts. The problem is that Parylene-C alone is too permeable to body water and the ions that are dissolved in it. Application as a coating material for long-term implants is therefore not possible. The infiltrating water not only corrodes the electronic components, but also reduces the adhesion between the Parylene-C and the coated surface. Therefore, layer systems of metal oxides and polymers are used for encapsulation. The aim of this work is to find out how different layer systems behave in relation to their water vapour transmission. Thicker systems should allow less water vapour to pass through than thinner ones. The task is to find this out using the test method for water vapour transmission barriers and to determine the water vapour transmission rate. It has been proven that in some cases the thicker layers performed worse than the thinner layer systems by a factor of ten. It has been shown that there is a relationship between the base substrate thickness, the thickness of the layer system and their flexibility.
ALD can be used in medical technology to produce thin and stable protective coatings. For example, such coatings can be used as tarnish and oxidation protection for silver electrodes used in high-frequency surgery. For the investigation of the pretreatment method, platelets of sterling silver were used instead of silver electrodes. Three methods were used to pretreat the silver substrates. The first pretreatment method is cleaning with acetone and isopropanol. In the other two, the samples are additionally cleaned with a phosphoric acid etching mixture or citric acid. The pretreated substrates were coated using the atomic layer deposition method. 45 nm of aluminum oxide was deposited on the silver samples, followed by another 45 nm of titanium oxide. Subsequently, the samples were autoclaved in order to check the clinical routine and the reusability. The results show a significantly improved adhesion in contrast to samples that were not cleaned. The layer no longer flakes off the silver substrate. Nevertheless, small blisters appear on the protective layer after autoclaving. These indicate that the layer is weakened by the stress.
Investigation on adhesion strength of Parylene-C coatings with different adhesion promotion methods
(2021)
Delamination of encapsulation materials (here the polymer Parylene-C) is one of the biggest failure mechanisms for active medical implants. This problem is addressed by the application of different pre-treatment and adhesion promotion methods. The methods applied in this research are oxygen and Silane A-174 solution pre-treatment and Silane A-174, titanium oxide and Trimethylsilane as adhesion promoters. The adhesion forces of these methods are quantified after different soaking times in phosphate buffered saline (PBS) solution to mimic environment of the human body.
In the present work, polyetheretherketone (PEEK) was pretreated with oxygen plasma to investigate the influence on the contact angle and surface energy. For this purpose, PEEK samples were fabricated over several manufacturing steps, which were used as substrates for later investigations. A series of measurements was performed at a power of 300 W for different treatment durations and the contact angle of H2O on the PEEK surface was determined. The results show that plasma pretreatment significantly affects the surface modification of PEEK disks. The best hydrophilic properties of the PEEK surfaces were measured at a treatment time of 540 s and a power of 300 W. A much longer treatment time caused the correlated values of contact angle and surface energy to increase and in this case an excessive treatment time did not contribute to a further increase in hydrophilicity.
Compared to relational databases, graph database systems provide a novel way of processing and analyzing highly interconnected data. Due to their unique properties, graph databases embody an interesting area of research in academic circles. For this reason, this work is fundamentally concerned with examining the state of the industry and current challenges. In this regard, we revisit the basic concepts and highlight the tremendous heterogeneity of available systems using the example of differing path semantics. Based on this insight, we explore algorithmic advancements for graph query processing regarding path finding and worst-case optimal joins. Subsequently, we discuss issues regarding performance and support for graph analytics. Finally, we provide an overview of GQL, a joint standardization effort towards unification of property graph databases.
Wikipedia is the largest free encyclopedia and one of the most popular websites worldwide. Analyzing user activity within this encyclopedic ecosystem represents unique opportunities for academic research and analysis. For this reason, this work is fundamentally concerned with obtaining and processing real-time article edit streams from Wikipedia. In this regard, we leverage the Wikimedia EventStreams API and propose a general-purpose event pipeline allowing for further processing of observed page edits. In the suggested pipeline, events are ingested and transported via an Apache Kafka cluster and inserted into a ClickHouse database for storage and analysis. Finally, we confirm the viability of our design by exploring several exemplary analytical use cases.
This work gives the theoretical background which is needed to understand what self-assembling monolayers are, how they work, how and for what they can be used. A closer look is taken on the possibility to create an area selective atomic layer deposition process. In a practical experiment the foundation for this process is laid. Therefor a silicon wafer is coated with gold using a evaporation process. The gold samples are exposed to the SAMs solution to grow them. Contact angle measurements as well as Fourier transform Infrared spectroscopy are used to check the existence of SAMs on the gold samples. Also there is investigated if different exposure times make any differences.
Parylene-C is used for various biomedical devices because of its high conformity and biocompatibility. However, delamination could occur because of low adhesion between Parylene-C and other materials. For this experiment 4-inch Si-wafers are used. Parylene is deposited by chemical vapour deposition (CVD). Silane A-174 as adhesion promoter is added between Parylene-Parylene layers. The samples are soaked at different duration 1 h, 24 h and 120 h in PBS solution at 37 °C. A peel test is further performed to investigate the adhesion properties of the samples.