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This PhD investigation lies at the intersection of Architecture, Textile Design and Interaction Design and speculates about sustainable forms of future living, focussing on bionic principles to create alternative lightweight building structures with textiles and digital fabrication techniques. In an interdisciplinary, practice- based design approach, informed by radical case studies from the 1960s to 80s on soft architectures like Archigram, Buckminster Fuller, Cedric Price, or Yona Friedman and critical theory on new materialism, (D. Haraway 1997, K. Barad 1998, J. Bennett 2007) sociological, philosophical (B. Latour 2005, G.Deleuze F., Guattari F 1987) and phenomenological thinkers (L. Malafouris 2005, J.Rancière 2004, B. Massumi 2002, N. Bourriaud 2002 , M. Merleau-Ponty 1963) this research investigates the cultural and social rootedness (Verortung) of novel materials and technologies, exploring in between prosthetic relations between the body and the environment.
Engineering and management
(2019)
Low temperature carburizing of a series of austenitic stainless with various combinations of chromium and nickel equivalents was performed. The investigation of the response towards low temperature carburized for three stainless steels with various Cr- and Ni-equivalents showed that the carbon uptake depends significantly on the chemical composition of the base material. The higher carbon content in the expanded austenite layer of specimen 6 (1.4565) and specimen 4 (1.4539/AISI 904L) compared to specimen 2 (1.4404/AISI 316L) is assumed to be mainly related to the difference in the specimens’ chromium content. More chromium leads to more lattice expansion. Along with the higher carbon content, higher hardness values and higher compressive residual stresses in the expanded austenite zone are introduced than for low temperature carburized AISI 316L. The residual stresses obtained from X-ray diffraction lattice strain investigation depend strongly on the chosen X-ray elastic constants. Presently, no values are known for carbon (or nitrogen) stabilized expanded austenite. Nevertheless, first principle elastic constants for γ′&minus Fe4C appear to provide realistic residual stress values. Magnetic force microscopy and measurement with an eddy current probe indicate that austenitic stainless steels can become ferromagnetic upon carburizing, similar for low temperature nitriding. The apparent transition from para- to ferromagnetism cannot be attributed entirely to the interstitially dissolved carbon content in the formed expanded austenite layer but appears to depend also on the metallic composition of the alloy, in particular the Ni content.
We present an innovative decision support system (DSS) for distribution system operators (DSO) based on an artificial neural network (ANN). A trained ANN has the ability to recognize problem patterns and to propose solutions that can be implemented directly in real time grid management. The principle functionality of this ANN based optimizer has been demonstrated by means of a simple virtual electrical grid. For this grid, the trained ANN predicted the solution minimizing the total line power dissipation in 98 percent of the cases considered. In 99 percent of the cases, a valid solution in compliance with the specified operating conditions was found. First ANN tests on a more realistic grid, calibrated with household load measurements, revealed a prediction rate between 88 and 90 percent depending on the optimization criteria. This approach promises a faster, more cost-efficient and potentially secure method to support distribution system operators in grid management.
The reliable supply of energy is an essential prerequisite for the economic success of a country. Questions of sustainability and the replacement of import dependencies require new tasks with new approaches. This contribution provides an overview of dependencies using the example of German electrical power grids integrating renewable energies. Aspects of energy trading and grid stability are brought into connection, stock exchange trading, grid codes and volatility of used primary energies are discussed.
Business coaching is believed to effectively improve survival and success chances of new technology-based firms (NTBFs). However, not much empirical evidence on the support measure's effectiveness is available. Therefore, a pragmatic two-armed Randomized Controlled Trial (RCT) to test the effect of tactical business coaching on NTBF survival capabilities was designed and, for the most part, carried out. However, due to a lower than expected sample size and great attrition between groups, the RCT reveals deviations from the trial design that impede a thorough data assessment. Based on the data given, a first data analysis does not reveal significant differences in survival capability between the two groups. Thus, to provide guidance for future RCTs in business contexts, lessons learned about how to deal with trickle samples and experiment constellations with third parties carrying out the intervention are drawn.
Vortrag und Abstract
A physics lab-setup has been developed for engineering students in their first year at university. The so-called LabTeamCoaching helps to improve general lab skills, such as preparing an experiment, writing a documentation, using graphs and drawing conclusions. By using a flipped classroom approach, students get better involved than in our former physics labs when we applied classical methods. This approach will be described and an overview of our 10 years of experience using this method will be given.
These days, medical applications of shape memory alloys (SMAs) can be found in cardiovascular devices, gastroenterology and urology as well as in the area of orthopedic implants, orthodontic devices and clinical instrumentation. Their functional properties combined with excellent biocompatibility increase the possibility and the performance of minimally invasive surgeries. Overviews of existing applications can be found in [1-2]. Within the medical field, most of the applications with shape memory (SM) material take advantage of the superelasticity of NiTi SMAs. In contradiction to the superelastic or mechanical SM effect, the application described in this study uses the thermal SM effect for a new medical implant. Before explaining the SM driven intramedullary bone nail in detail, a short introduction to the bone elongation technique is given.
The background of this application on based in the medical fact that normally any tissue reacts to an injury with repair and healing processes through multiplication of cells. If after a transverse osteotomy a strain stimulus is activated, for example by tensile stress, this multiplication of cells and new formation of tissue may be continued for any length of time. Due to this mechanism, even considerable loss of bone caused by fractures or congenital defective positions, may be compensated without bone grafts. The technique of callus distraction by means of external fixation or intramedullary nail stimulates the formation of callus in the bone gap. Callus is the repair tissue of the bone generated in the fracture gap in case of bone fracture or osteotomy. The gap to be bridged should not be wider than 1 mm per day [3]. The process starts with the exudation of callus around the ends of the broken bone. At first, callus is more like a fibrous tissue. Later it hardens due to deposition of calcium and eventually it is converted into true bone. Three weeks after severance, the vascular system is formed. An overview of current bone lengthening techniques, also called callus distraction, can be found in [3]. External systems are normally used for the extension of bones, the bone fragments being fixed on rings by wires. The decisive disadvantages of those external systems are primarily the considerable risk of infection due to protruding wires, noticeable discomfort for the patient because of the external rings, a coarse cosmetic result because of scarring, as well as rather long hospitalization.
Therefore, internal bone extension systems are of great interest to orthopedic surgery.