MEMS micro-bridge actuator for potential application in optical switching

In this thesis, the development of a novel electro-thermally actuated bi-stable out-of-plane two way actuated buckled micro-bridge for a potential application in optical switching is presented. The actuator consists of a bridge supported by 'legs' and springs at its four corners. The springs and the bridge are made of a tri-layer structure comprising of 2.5µm thick low-stress PECVD oxide, 1µm thick high-stress PECVD oxide and 2µm thick heavily phosphorus doped silicon. The legs, on the other hand, are 2µm thick single layer heavily phosphorus doped silicon. Both legs and springs provide elastically constrained boundary conditions at the supporting ends, without of which important features of the micro-bridge actuator could not have been achieved. This microbridge actuator is designed, simulated using ANSYS, fabricated and tested. The results from the testing have shown a good agreement with analytical prediction and ANSYS simulation. The actuator demonstrated bi-stability, two-way actuation and 31µm out-of-plane movement between the two-states using low voltage drive. Buckled shape model, design method for bi-stability and thermo-mechanical model are developed and employed in the design of the micro-bridge. These models are compared with Finite Element (FE) based ANSYS simulation and measurements from the fabricated micro-bridge and have shown a good agreement. In order to demonstrate the potential application of this actuator to optical switching, ANSYS simulation studies have been performed on a micro-mirror integrated with the micro-bridge actuator. From these studies, the optimum micro-mirror size that is appropriate for the integration has been obtained. This optimal mirror size ensures the important features of the actuator. Mirror fabrication experiments in (110) wafer have been carried out to find out the appropriate compensation mask size for a given etch depth and the suitable wafer thickness that can be used to fabricate the integrated system

Developing satellite communications for public service: Prospects in four service areas

The Public Service Satellite Consortium evaluated prospects for satellite telecommunications in four areas of the public service: the U.S. health care system, elementary and secondary education, American libraries, and that sector of the public service which is concerned with the provision of continuing education to health professionals. Three important conclusions were reached. First, throughout the public service there are three recurring needs: improved access, cost containment, and maintenance of quality. Appropriate application of communication satellite systems could ameliorate each of these concerns. Second, there appears to be an enormous latent demand for data communication services throughout the public service. The potential demand in 1982 to support requirements in hospital administration, library services and other information-retrieval activities, equipment maintenance, and environmental monitoring may be in excess of $300 million a year. Third, administrative applications of data communication networks show particular promise, especially in rural areas

Online development in the Nordic countries : a history of online information from the 1960s to the '00s and NORDINFO's role in its development

Some of the contributions to this book have previously been published as unedited manuscripts in 2007 at http://hdl.handle.net/1975/149

Perception of Reverberation in Domestic and Automotive Environments

nrpages: 227status: publishe

The feasibility of electronic journals: some studies in human–computer interaction

Computer-based tools for communication are a recent technological development. They promise to provide new routes by which to communicate with others and to transform some communications that have hitherto been dependent on media such as paper. One example is the possibility of supporting scholarly communication by the use of electronic systems, which also promises a method by which the information explosion might be handled. The research is an examinat4on of whether or not the support of scholarly communication in this way is feasible. To investigate communication systems requires a large scale study over a long period. Accordingly the research rests on a study programme on 'electronic journals', BLEND, which ran from 1980 to 1984, funded by the British Library Research and Development Department. The feasibility of ielectronic journals is investigated by exploring the usability, utility, likeability and cost-effectiveness of the communications system. An analysis of the frequency and distribution of the use of the computer-based communications system showed that many things seemed to get in the way of accessing it. Several techniques were used to examine this: transaction recording, interviews, telephone surveys, questionnaires and analysis of requests for help. Once the system was accessed, a comparison of users' aims with actual use shows that different forms of the journal should be explored in the future. Two reasons for the access rate and type of use made of the system was the degree to which researchers were able to accommodate the use of a new communications system into existing patterns of work and the level of usability of the system. One area in usability that is explored in detail is the way that text can be read easily on a screen. The cost-effectiveness of the system is examined by projecting from actual costs and patterns of use. The final chapters bring together the studies in a 'Barrier' framework for understanding the use of a communications system and look forward to the future of electronic journals

NOTIFICATION !!!

All the content of this special edition is retrieved from the conference proceedings published by the European Scientific Institute, ESI. http://eujournal.org/index.php/esj/pages/view/books The European Scientific Journal, ESJ, after approval from the publisher re publishes the papers in a Special edition

NOTIFICATION!!!

The full content of this special edition is retrieved from the conference proceedings published by the European Scientific Institute, ESI. http://eujournal.org/index.php/esj/pages/view/books The European Scientific Journal, ESJ, after approval from the publisher re publishes the papers in a Special edition

NOTIFICATION !!!

All the content of this special edition is retrieved from the conference proceedings published by the European Scientific Institute, ESI. http://eujournal.org/index.php/esj/pages/view/books The European Scientific Journal, ESJ, after approval from the publisher re publishes the papers in a Special edition

NOTIFICATION !!!

All the content of this special edition is retrieved from the conference proceedings published by the European Scientific Institute, ESI. http://eujournal.org/index.php/esj/pages/view/books The European Scientific Journal, ESJ, after approval from the publisher re publishes the papers in a Special edition

NOTIFICATION !!!

All the content of this special edition is retrieved from the conference proceedings published by the European Scientific Institute, ESI. http://eujournal.org/index.php/esj/pages/view/books The European Scientific Journal, ESJ, after approval from the publisher re publishes the papers in a Special edition