Zugl.: Jena, Univ., Diss., 2006

No description available.

Report (M. Engr.)--Virginia Polytechnic Institute and State University, 1994. / Includes bibliographical references (leaves 43-54). Also available via the Internet.

The aim of this thesis is to provide a design tool for the engineering analysis of the dynamics of a flexible riser system. The design tool is piovided in the form of a computer program. The two main requirements of such a program are that it is realistic and practical to use. The necessary theory is developed to allow these requirements to be satisfied. To ensure accuracy checks are made against model tests and known analytical solutions. How the computer program may be used is shown by analysing a particular riser configuration.

The current work was initiated to develop, understand and optimise a novel computer controlled, automated, flexible compression moulding system primarily for the production of fluid seals. A prototype moulding system was designed and built for the study. It was used to process a range of rubber compounds for process evaluation.

The subject of theatre is a diverse and flexible subject that requires th$e freedom of expression. This can be engendered in the spatial configuration of its usable spaces. The reinvention of the Drama department inquires into becoming a cultural node within the University by facilitating functional flexible spaces for the rehearsal and performance of theatrical experiences affecting both teh student and the public. / Dissertation (MInt(Prof))--University of Pretoria, 2009. / Architecture / unrestricted

Process support is a core organisational competence which aims to help people plan and perform their work. This thesis addresses process support for Emergent Knowledge Processes (EKP). EKP can be characterised by human-orientation, emerging domain requirements, compliance requirements and dispersed participants/stakeholders. Current Process Aware Information Systems (PAIS) do not meet several important support requirements of EKP. Addressing these requirements will create business value. Through a Design Science (Hevner, March et al. 2004) research approach, this thesis addresses that problem. An approach to support EKP is conceptualised and implemented. The main contribution is a prescriptive framework. The framework consists of four components; interactive modelling, a combination of procedural and declarative models, flexible model management and real-time collaborative working. Interactive modelling is an approach to flexible process support where users create, adapt, analyse and enact visual models of their work processes. Underpinning the interactive modelling approach are both procedural and declarative models. Declarative models capture organisational rules. Procedural task-based models capture actual plans of work. Procedural models must comply with the rules established in the declarative models. Flexible model management and real-time collaboration support offer a cooperative working and knowledge management environment for interactive modelling. The conceptual design ideas have been realised in an academic software prototype. A Web-based groupware application, D2P, was developed as a 'plug-in' for the collaborative, Web-based modelling environment PowerMeeting. It is shown how Web technology can be leveraged for collaborative process support. A contribution is made through further demonstration of the applicability of Web-based solutions for professional, process related business requirements. As a final contribution, the results of a usability study demonstrate the usability of the D2P and PowerMeeting tools. Empirical evidence in the form of results from a usability study and user questionnaire confirmed that semi-skilled users with a small amount of training can activate the concepts and tools which make up the approach. Of particular importance is the demonstration of the usability of the less familiar declarative modelling paradigm. Scenarios are also provided to demonstrate the applicability of the approach.

New technologies will require more and more compliant materials capable of conforming to curved surfaces, i.e., able to stretch and mechanically resist body motions for wearable and on-skin applications. In this regard, this work discusses strategies to induce stretchability in materials. We focused our attention on improving the elasticity of transparent conducting electrodes (TCE) based on PEDOT:PSS and semiconductors (active layer) for organic solar cells. Firstly, the introduction of DMSO and Zonyl as additives into PEDOT:PSS was shown to produce highly transparent conducting electrodes (FoM > 35) with low Young’s modulus and high carrier density. We investigated the relationship between the transport properties of PEDOT:PSS and the morphology and microstructure of its films. The combination of the two additives enhances the fibrillary nature and the aggregations of both PEDOT and PSS components of the films. Secondly, stretchable TCEs based on PEDOT:PSS were fabricated using an innovative approach that combines an interpenetrated polymer network-based on polyethylene oxide and Zonyl. The presence of three-dimensional matrix provided high electrical conductivity, elasticity, and mechanical recoverability. The potential of this electrode was demonstrated with indium-tin-oxide (ITO)-free solar cells with a power conversion efficiency similar to ITO. Finally, the research was completed by integrating a cross-linker or an elastomer into the active layer to enhance its stretchability while maintaining excellent photovoltaic performance. In particular, SEBS elastomer exhibited a tailored elasticity with various fullerene and non-fullerene blends: P3HT:PC61BM, PCE10:PC71BM and PCE13:IT-4F. This versatile approach highlights the ease of manufacturing and scalability achieved by the solution casting processes along with a high compatibility of acceptor and donor blends.

With the projected growth of the flexible and plastic electronics industry, there is renewed interest in the research community to develop high performance all-polymeric memory which will be an essential component of any electronic circuit. Some of the efforts in polymer memories are based on different mechanisms such as filamentary conduction, charge trapping effects, dipole alignment, and reduction-oxidation to name a few. Among these the leading candidate are those based on the mechanism of ferroelectricity. Polymer ferroelectric memory can be used in niche applications like smart cards, RFID tags, sensors etc. This dissertation will focus on novel material and device engineering to fabricate high performance low temperature polymeric ferroelectric memory for flexible electronics. We address and find solutions to some fundamental problems affecting all polymer ferroelectric memory like high coercive fields, fatigue and thermal stability issues, poor breakdown strength and poor p-type hole mobilities. Some of the strategies adopted in this dissertation are: Use of different flexible substrates, electrode engineering to improve charge injection and fatigue properties of ferroelectric polymers, large area ink jet printing of ferroelectric memory devices, use of polymer blends to improve insulating properties of ferroelectric polymers and use of oxide semiconductors to fabricate high mobility p-type ferroelectric memory. During the course of this dissertation we have fabricated: the first all-polymer ferroelectric capacitors with solvent modified highly conducting polymeric poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) [PEDOT:PSS] electrodes on plastic substrates with performance as good as devices with metallic Platinum-Gold electrodes on silicon substrates; the first all-polymer high performance ferroelectric memory on banknotes for security applications; novel ferroelectric capacitors based on blends of ferroelectric poly(vinylidene fluoride trifluoroethylene) [P(VDF-TrFE)] and highly insulating dielectric poly(p-phenylene oxide) [PPO] with drastically improved fatigue and thermal stability; novel all-polymer ferroelectric diodes based on blends of ferroelectric [P(VDF-TrFE)] and n-type semiconducting [6,6]-phenyl-C61-butyric acid methyl ester [PCBM] with resistive switching properties and the first hybrid p-type ferroelectric memory with transparent tin monoxide [SnO] on plastic substrates with record mobilities.

In this work, the development of a Thermoelectric Generator on Flexible Silicon Fabric is explored to extend silicon electronics for flexible platforms. Low cost, easily deployable plastic based flexible electronics are of great interest for smart textile, wearable electronics and many other exciting applications. However, low thermal budget processing and fundamentally limited electron mobility hinders its potential to be competitive with well established and highly developed silicon technology. The use of silicon in flexible electronics involve expensive and abrasive materials and processes. In this work, high performance flexible thermoelectric energy harvesters are demonstrated from low cost bulk silicon (100) wafers. The fabrication of the micro- harvesters was done using existing silicon processes on silicon (100) and then peeled them off from the original substrate leaving it for reuse. Peeled off silicon has 3.6% thickness of bulk silicon reducing the thermal loss significantly and generating nearly 30% more output power than unpeeled harvesters. The demonstrated generic batch processing shows a pragmatic way of peeling off a whole silicon circuitry after conventional fabrication on bulk silicon wafers for extremely deformable high performance integrated electronics. In summary, by using a novel, low cost process, this work has successfully integrated existing and highly developed fabrication techniques to introduce a flexible energy harvester for sustainable applications.