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Dissertations / Theses on the topic 'Electrical and Electronic Technology'
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Cohen, Sharon B. "Auditing technology for electronic voting machines." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33119.
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Thesis (M. Eng. and S.B.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.<br>Includes bibliographical references (leaf 63).<br>Direct Recording Electronic (DRE) voting machine security has been a significant topic of contention ever since Diebold voting machine code turned up on a public Internet site in 2003 and computer scientists at Johns Hopkins University declared the machine "unsuitable for use in a general election." Since then, many people from computer scientists to politicians have begun to insist that DREs be equipped with a paper trail. A paper trail provides a paper printout for the voter to approve at the end of each voting session. Although there have been strong political efforts to place paper trails on DRE machines, there have not been any scientific studies to indicate that paper trails are effective audits. This work describes a user study done to compare paper trails to audio audits, a new proposal for DRE auditing. Participants in the study completed four elections on a voting machine with a paper trail and four elections on a machine with an audio trail. There were purposeful mistakes inserted into the audits on some of the machines. Results from the study indicated that participants were able to find almost 10 times as many errors in the audio audit then they were able to find in the paper trail. Voters' attitudes towards the paper audit were extremely apathetic, and voters did not spend much time reviewing their paper record. When asked which type of audit voters would prefer for their own county elections, almost all voters preferred the VVPAT. These results indicate that newer alternative audit technology holds great promise in delivering a safe and accurate audit and further that paper trails have some significant design obstacles that need to be overcome before they will be effective audits.<br>by Sharon B. Cohen.<br>M.Eng.and S.B.
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Serdyn, J. J. "Electronic voltage regulator technology for rural electrification." Thesis, Link to the online version, 2008. http://hdl.handle.net/10019/903.
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SENA, FABRICIO ROBERTO. "EVOLUTION OF MOBILE PHONES TECHNOLOGY AND THE IMPACT ON THE WASTE OF ELECTRICAL AND ELECTRONIC EQUIPMENT." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2012. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=22231@1.
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Os produtos da indústria de eletroeletrônicos possuem alta empregabilidade no dia a dia. No entanto, por terem um ciclo de vida curto impactam na demanda por recursos naturais não renováveis. Dentro do universo de equipamentos eletroeletrônicos, os telefones celulares estão entre os mais complexos e os que empregam maior quantidade de elementos químicos diferentes. Apesar de pequenos, são vendidos aos milhares, em parte devido a sua curta vida útil. Esses fatores aliados indicam a existência de riscos à saúde e ao meio ambiente, o que faz repensar como destinar corretamente esses aparelhos no pós-consumo. A proposta do trabalho é fazer uma análise de como os telefones celulares impactam no volume e na complexidade dos Resíduos de Equipamentos Eletroeletrônicos, explicar a razão desse bem essencial ter uma vida útil tão curta e expor os motivos que tornam a sua reciclagem absolutamente necessária para continuar o seu desenvolvimento tecnológico, atender a demanda dos consumidores e reduzir o impacto ambiental da produção ao descarte.<br>In the last century, through new production processes, the industry has increased the variety and availability of products offered to the population, providing better quality of life. This has happened because the inception of series production has offered a greater supply of consumer goods, including the Electrical and Electronic Equipment (EEE).
The evolution of electronics technology has provided, and will continue to provide a better quality of life than the one we used to have. However, the technology of these products is continuously evolving, and this brings advantages and disadvantages.
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Molinari, Marc. "High fidelity imaging in electrical impedance tomography." Thesis, University of Southampton, 2003. https://eprints.soton.ac.uk/45805/.
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This thesis addresses the computational reconstruction of images using Electrical Impedance Tomography (EIT). EIT is an imaging method, in which electrical currents are injected through electrodes into a conducting volume and the resulting potential distribution is measured at surface electrodes. From these potentials, an image of the electrical conductivity can be obtained using numerical reconstruction techniques. This non-linear reconstruction is mathematically difficult and computationally intensive. Most applications in medicine and industry rely upon a fast and accurate image acquisition. The aim of this investigation is to find methods which improve the speed and accuracy of EIT by a range of improvements to the numerical methods used in the forward solution and inverse reconstruction. We investigate the impact of the finite element discretization on the performance of computing the electric field forward solution. We derive an a posteriori error estimate on the finite element mesh and implement 2D adaptive mesh refinement techniques in an optimised forward solver. Our results of this novel approach show that a speed-up of approximately an order of magnitude can be obtained. We extend the developed iterative Newton-Raphson algorithm to include image smoothness constraints and adaptive mesh refinement based on conductivity gradients in the image. The results show that the image resolution can be made independent of the underlying numerical discretization and therefore is limited only by the level of noise present in the measurements. An additional benefit of this new technique is the automatic focus of available computational resources on key regions for forward solution and inverse reconstruction. As 3D impedance imaging becomes computationally too expensive for the Newton-Raphson method, we develop a novel non-linear conjugate gradient algorithm incorporating 3D adaptive mesh refinement routines, and present results showing the decrease of memory requirements and the increase in image reconstruction performance. In addition, a Matlab software package containing optimised routines for the finite element-based computations in EIT has been developed as part of this work. Finally, we outline a method for obtaining a map for the determination of the reconstruction reliability and image correlation of an EIT algorithm. With the improvements to reconstruction accuracy and speed investigated in this thesis, we conclude that efficient non-linear 3D impedance imaging is feasible
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Miller, Jimmie Andrew. "From STM to nanomemory : a transfer of technology feasibility study." Thesis, University of Warwick, 1994. http://wrap.warwick.ac.uk/2246/.
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Recent years have seen exponential increase in memory capacity for computer data storage. Increased bit density has been produced by decreasing feature sizes in microelectronic fabrication. As minimum microelectronic feature sizes are realized, new methods are being investigated to continue the increase in recording bit density. This report examines features which are necessary to produce an electron-tunneling based memory which is postulated to increase the data density by a factor of 105-106 over current manufactured memories. A description is given for combining tunneling microscopy with memory technology to achieve this high density memory. Experiments using a tunneling tip to produce nanometer scale features on a surface are recounted. The repeatability and durability of the produced features are investigated with a summary of these aspects included for various materials reported in the literature. Some necessary mechanical and electrical design criteria for a tunneling memory are obtained. Observed and reported inconsistency in nanometer lithography are attributed to nonpredictable tunneling currents and resulting tip-sample separations. Experimental and theoretical work scrutinizing tunneling currents as a function of tip-sample displacement is included. Other factors affecting the practicality of a tunneling based memory are also incorporated.
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Gresham, Christopher Allen 1965. "Near-infrared spectroscopy utilizing array detector technology." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282690.
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A near-infrared spectrometer incorporating solid-state design applicable for industrial quantitative/qualitative process monitoring analysis is presented. The solid-state near-infrared spectrometer provides inherent wavelength stability necessary for long term calibration accuracy. The spectrometer consists of a 24 volt, 10 watt quartz-halogen-tungsten regulated source with optical feedback. Wavelength dispersion was accomplished using a 50 μm entrance slit, f/4, 0.25 meter spectrograph equipped with astigmatism correcting toroidal mirrors and a 300 gr/mm plane reflectance ruled grating blazed for 2000 nm peak efficiency. A 1024 element backside- illuminated Schottky-barrier PtSi photodiode array detector with wavelength response from 900-5000 nm and peak quantum efficiency of 8% at 1100 nm was operated using cryogenic cooling to reduce dark response. A readout rate of 31.25 kHz produced 41 msec integration time per array read. The readout was digitized to 16 bit resolution for subsequent data storage. This system demonstrated 1.5 nm spectral bandpass, 3 orders linear dynamic range and typical baseline rms noise level of 10⁻⁴ a.u. Using this system, quantitative/qualitative chemical analyses were performed focusing on industrial analytical chemical applications. Simultaneous quantitative multcomponent xylene isomer mixtures analysis was achieved using the solid-state near-infrared spectrometer coupled with partial least squares regression multivariate data treatment. The results demonstrate an absolute accuracy of ± 0.05, ±0.12 and ±0.09% w/v for o-, m- and p-xylene isomers respectively. In a separate chemical study, qualitative classification analysis of specially denatured alcohol mixtures was successfully performed on 53 validation samples using 35 reference samples belonging to 12 classes. The validation set included mixture sample types used for model calibration as well as others composed of compounds not used for model calibration. The multivariate cluster classification method using principal components was employed to correctly classify 100% of the validations samples analyzed. The solid-state near-infrared spectrometer was also applied for direct reaction monitoring of the O-H overtone absorption band at 1411 nm for the reaction between triisopropyl-chlorosilane and methanol. The results illustrated the utility of near-infrared functional group monitoring of reactions at relatively high concentrations for information elucidation concerning reaction initiation and completion.
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Larsson, Johan. "Distance Estimation and Positioning Based on Bluetooth Low Energy Technology." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-174857.
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This thesis deals with location determining, also known as positioning, using Bluetooth Low energy radio. The goal is to implement a low power low cost indoor positioning system which utilize existing hardware. Two main methods are investigated and their viability assessed. Previous efforts with indoor positioning systems concentrate on statistical fingerprinting methods, mainly using 802.11 (WLAN) as the platform. Some efforts have been made with purely signal strength based positioning, but indoor environments have shown to work unfavorably for these kinds of methods.
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Kumari, Neha. "Feasibility Study for Substation Communication using Parallel Redundant Wireless Technology." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-254361.
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Substations are an integral part of electric energy transmission and distribution system. With the evolution of conventional substations as digital substations, and in parallel, with the revolutionized emergence of communication systems, new communication schemes are being designed and retrofitted to incorporate the data from relays, circuit breakers and Intelligent Electronic Devices (IEDs) to integrate with the new digital substations.The thesis thus aims in evaluating a few wireless technologies to address the availability and reliability at the process level of Digital Substation System. It is achieved by introducing a redundant wireless network in parallel to existing wired solutions. For the purpose three wireless technologies IEEE 802.11g and Standalone 4G LTE network Base Station (BS) have been evaluated experimentally in a laboratory environment and 5G has been evaluated in a software simulated environment.The experimental results corresponding to IEEE 802.11g and 4G had their own limitations and faced a few challenges in meeting the process level Sampled Value data requirements. Whereas 5G showed a positive result in most of the scenarios, meeting the process bus requirement in terms of latency and packet loss.
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De, Villiers Edward. "Automatic alignment and error detection for phonetic transcriptions in the African speech technology project databases." Thesis, Stellenbosch : University of Stellenbosch, 2006. http://hdl.handle.net/10019.1/2311.
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Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2006.<br>The African Speech Technology (AST) project ran from 2000 to 2004 and involved collecting speech data for five South African languages, transcribing the data and building automatic speech recognition systems in these languages. The work described here form part of this project and involved implementing methods for automatic boundary placement in manually labelled files and for determining errors made by transcribers during the labelling process.
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Yu, Lili Ph D. Massachusetts Institute of Technology. "MoS₂ electronics : technology, high yield circuits and applications." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/108993.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 177-186).<br>In the last few decades, the device community has explored a large number of technologies beyond silicon, that not only allow for further shrinkage in electronic systems size and power but can also provide new features, such as mechanical flexibility, large-area coverage at low cost thanks to inkjet printing, and simplified 3D integration. Two-dimensional electronics based on single-layer MoS₂ synthesized by chemical vapor deposition (CVD) offers significant advantages for realizing large-scale flexible systems owing to the ultrathin nature, excellent transport properties and stable crystalline structure of MoS₂. Despite all the progress, the MoS₂ electronics demonstrated so far is limited to single or few-device- scale circuits built on exfoliated flakes due to the many challenges associated with the uniformity and yield control in both material growth and device technologies. This thesis addresses issues which are crucial for realizing reliable, and high-yield complex circuits using emerging 2D materials, such as MoS₂: (1) Develop large-area material synthesis and transfer methods, as well as some of the first technologies for reliable enhancement mode MoS₂ transistors. (2) Design an automatic flow for fast implementation of complex circuits using MoS₂.Compact models and a process development kit (PDK) are developed for MoS₂ and are used to successfully implement both digital and analog circuits. (3) Study the sources of variability in MoS₂ devices and circuits and improve circuits yield by material, process, and device and circuit design co-optimization. (4) Demonstrate two system-level applications of CVD MoS₂: active matrix backplane circuits for transparent displays and radio frequency energy harvester. (5) Demonstrate the first air-stable CMOS technology monolithically integrated on WSe₂ to offer low power electronic solution. The future opportunities and potential challenges for all these technologies are also discussed. This thesis, in summary, provided important guidelines on how to take a new proof-of-concept material/device and make it into a useful technology to enable practical applications.<br>by Lili Yu.<br>Ph. D.
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Jun, Lu, and Zhang Song. "E-health web application framework and platform based on the cloud technology." Thesis, Högskolan Kristianstad, Sektionen för hälsa och samhälle, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hkr:diva-11108.
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This project deals with E-health web application framework, cloud platform and responsive web design which aim to adjust the presentation on mobile devices. This work presents the whole development process of the self-care management web-app framework which provides instructive supports for future other E-health field application. The report consists of the following main parts: analysis, design and implementation, and evaluation. Literature review and internet search are main methods for making an investigation on existing systems and related works. A prototype is developed by using .Net, CSS3, Java script and HTML5 technologies. The system test and evaluation is made to show the system’s usability.
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Junered, Marcus. "Enabling hardware technology for GNSS software radio research." Licentiate thesis, Luleå : Luleå University of Technology, 2007. http://epubl.ltu.se/1402-1757/2007/32/.
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Shin, Hyun Woo. "A hybrid electronic nose system for monitoring the quality of potable water." Thesis, University of Warwick, 1999. http://wrap.warwick.ac.uk/111031/.
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This PhD thesis reports on the potential application of an electronic nose to analysing the quality of potable water. The enrichment of water by toxic cyanobacteria is fast becoming a severe problem in the quality of water and a common source of environmental odour pollution. Thus, of particular interest is the classification and early warning of toxic cyanobacteria in water. This research reports upon the first attempt to identify electronically cyanobacteria in water. The measurement system comprises a Cellfacts instrument and a Warwick e-nose specially constructed for the testing of the cyanobacteria in water. The Warwick e- nose employed an array of six commercial odour sensors and was set-up to monitor not only the different strains, but also the growth phases, of cyanobacteria. A series of experiments was carried out to analyse the nature of two closely related strains of cyanobacteria, Microcystis aeruginosa PCC 7806 which produces a toxin and PCC 7941 that does not. Several pre-processing techniques were explored in order to remove the noise factor associated with running the electronic nose in ambient air, and the normalised fractional difference method was found to give the best PCA plot. Three supervised neural networks, MLP, LVQ and Fuzzy ARTMAP, were used and compared for the classification of both two strains and four different growth phases of cyanobacteria (lag, growth, stationary and late stationary). The optimal MLP network was found to classify correctly 97.1 % of unknown non-toxic and 100 % of unknown toxic cyanobacteria. The optimal LVQ and Fuzzy ARTMAP algorithms were able to classify 100% of both strains of cyanobacteria. The accuracy of MLP, LVQ and Fuzzy ARTMAP algorithms with 4 different growth phases of toxic cyanobacteria was 92.3 %, 95.1 % and 92.3 %, respectively. A hybrid e-nose system based on 6 MOS, 6 CP, 2 temperature sensors, 1 humidity sensor and 2 flow sensors was finally developed. Using the hybrid system, data were gathered on six different cyanobacteria cultures for the classification of growth phase. The hybrid resistive nose showed high resolving power to discriminate six growth stages as well as three growth phases. Even though time did not permit many series of the continuous monitoring, because of the relatively long life span (30-40 days) of cyanobacteria, improved results indicate the use of a hybrid nose. The HP 4440 chemical sensor was also used for the discrimination of six different cyanobacteria samples and the comparison with the electronic nose. The hybrid resistive nose based on 6 MOS and 6 CP showed a better resolving power to discriminate six growth stages as well as three growth phases than the HP 4440 chemical sensor. Although the mass analyser detects individual volatile chemicals accurately, it proves no indication of whether the volatile is an odour. The results demonstrate that it is possible to apply the e-nose system for monitoring the quality of potable water. It would be expected that the hybrid e-nose could be applicable to a large number of applications in health and safety with a greater flexibility.
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El, Karimi Naoual. "Design and implementation of a personal assistant using agent technology." Thesis, University of Ottawa (Canada), 2004. http://hdl.handle.net/10393/26632.
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Intelligent agents are rapidly gaining popularity in our increasingly networked world since their emergence at the beginning of the last decade as a promising design and implementation solution for future applications. They provide information monitoring, searching filtering, and decision aiding that help people focus on the information that is most pertinent to them in a particular context.
One central class of agents is personal assistants. They can be distinguished from ordinary agents by the fact that they work at the interface level rather than the application level. They model their owners' interests, provide services to them, and act on their behalf when required. Their domains of application include Internet information retrieval, E-commerce, telecommunication, and network management.
This thesis aims to present a general model of personal assistants using agent technology. The proposed model aims to efficiently provide all necessary functionality regardless of the application. Our system architecture consists of three distinct agents. They are the User Interface Agent, Information Management Agent, and Personal Agent. They communicate with each other, with the human user, and with other agents using Agent Communication Language in order to provide services to their owners. The model was applied in the Virtual Team Collaboration project as an agent that helps the user managing his Agenda, managing the team, scheduling meetings, and acting on the user's behalf. The thesis work show also how can we use our model of personal assistant in E-commerce.
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Miah, Md Suruz. "Autonomous mobile robot navigation using RFID technology." Thesis, University of Ottawa (Canada), 2007. http://hdl.handle.net/10393/27891.
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Navigation techniques are of a paramount importance in the field of mobile robotics. They are employed in many contexts in indoor and outdoor environments such as delivering payloads in a dynamic environment, building safety, security, building measurement, research, and driving on highways. Skilled navigation in mobile robotics usually requires solving two problems, determining the position of the robot, and selecting a motion control strategy. Moreover, when no prior knowledge of the environment is available, the problem becomes even more difficult, as the robot has to build a map of its surroundings as it moves. These three tasks ought to be solved in conjunction, since they depend on each other.
This dissertation explores the design of a cost-effective and modular navigation method for mobile robots. In particular, we will look at the process of navigating a mobile robot using the emerging RFID technology. A successful realization of this process has been addressed with two separate navigation modules. Each module presents a separate navigation algorithm for a mobile robot. In the first module, a customized RFID reader is mounted on the robot. The information provided by the reader will then be used for navigation. On the contrary, in the second module, custom-made RFID tags are attached at different locations in the navigation environment (on the ceiling of a building, posts, for instance). The position of the mobile robot is then determined based on the information provided by the tags in the robot's operating region. The angle between the robot's current direction and the target tag is used to provide actions to the actuators. In both modules, the algorithms take advantage of using analogue features of the RFID system instead of relying only on the binary tag number which conventional RFID-driven applications depend on.
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Stahrberg, Casper, and Oscar Pallin. "Investigation of compact rotor position sensor technology." Thesis, Uppsala universitet, Institutionen för elektroteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-455361.
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Electric vehicles are increasing on the market and new technologies are being investigated because of the demand placed on electrified drivelines to provide maximum efficiency. Electric motors are expected to provide high efficiency and thus precise and compact designs of sensors for electric motors are requested. Market sensors offers a broad variety of sensors which are useful and optimal for different applications. Inductive sensors are investigated by industries because of their characteristics of having high accuracy, robustness, compact and flexible design and tolerant to harsh environments. This thesis is an investigation of inductive position sensors for automotive rotor applications,requested by one of Sweden’s largest companies within the automotive industry. The goal of the project is to design and implement theory of tradtional resolver technology on a printed circuit board (PCB) and conduct concept verifications of the system. Furthermore a new concept in the design is introduced and applied to the angular position sensor, working as a vernier scale and improve the resolution. Results and outcomes of this thesis are meant to facilitate future work and breakthroughs regarding inductive position sensors. This thesis aim to conduct a deep dive in electronics and signal processing and to derive the fundamentals of electromagnetism, from Maxwell’s equations to modern sensor design and to bring a new discussion to the table regarding the traditional measuring target used for rotor position in automotive industries. A new design working as rotor target design is presented and verified in this thesis and the results and outcomes are meant to facilitate future work and breakthroughs regarding inductive position sensors and potentially increase the accuracy and thus the efficiency of electric vehicles.
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Robertson, Toby James Gray. "Advances in ultrasonic capacitive transducer technology." Thesis, University of Warwick, 2001. http://wrap.warwick.ac.uk/66936/.
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This thesis describes the development and characterisation of a variety of novel capacitive ultrasonic transducers for use in air-coupled and immersion applications. The first sections of this thesis examine the fabrication and initial characterisation of novel fully micromachined transducers. These devices, produced using a silicon surface micromachining process, consisted of a large laterally dimensioned (up to 5mm square), silicon nitride membrane, typically O.S-2I1m in thickness, above a nominal 211m air gap. Typical operation in air was observed in the MHz region. The effects of membrane thickness and size were studied, as well as the effect of applied bias voltage. Differences between batches of devices were investigated. Their dynamic membrane displacements were measured using interferometric techniques. When driven with transient voltages typical displacements of a few nm were observed. Their radiated fields were also investigated, and compared to plane piston approximations, calculated with a Matlab™ program. Good agreement was found. This thesis also describes the development and characterisation of three novel aircoupled focusing transducers. Two of these devices utilised shaped backplates, one being cylindrically concave, and the other conically concave, to produce lines of focus. The third device utilised an off-axis parabolic mirror to produce a point of focus. The development and characterisation of each is described. Their frequency responses were measured, and found to be comparable with similar planar transducers. Experiments were devised to measure their vertical and lateral resolutions, the latter typically being found to be approximately a wavelength of their centre operating frequency (-500kHz). Their radiated peak sound pressure fields were measured, and for the cylindrical and conical device compared to theoretical plane piston approximations calculated with a Matlab™ program, with good agreement of form being found. Finally, all three transducers were used to create 3-D images of a two pence coin, using amplitude and time of arrival data. Reasonable images resulted. The final section. examines the development of an immersion transducer. This was characterised as both source and receiver, showing increases in both bandwidth and frequency response than when used in air. The effects of backplate surface properties on the characteristics of the device were studied. using a range of roughened, polished, and photolithographic metallic backplates. In addition, the effect of applied bias was also investigated. Sound pressure fields were measured, using both broadband and narrowband tone burst excitations. and compared to theoretical predictions from plane piston theory. These were calculated using a Matlab™ program, with good agreement found. The transducer was then used to produce pulse-echo C-scan images of artificially induced machined defects in Perspex and aluminium plates. Excellent images resulted.
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Li, Wei Ph D. Massachusetts Institute of Technology Department of Electrical Engineering and Computer Science. "Design & optimization of automotive power electronics utilizing FITMOS MOSFET technology." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/53317.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 178-179).<br>Power electronics are essential to many automotive applications, and their importance continues to grow as more vehicle functions incorporate electronic controls. MOSFETs are key elements in automotive power electronic circuits and MOSFET characteristics can strongly affect circuit size, cost and performance. Advances in MOSFET technology are thus of great importance to the advancement of automotive electronics. The new Floating Island and Thick Bottom Oxide Trench Gate MOSFET (FITMOS) developed at Toyota has tremendous potential for automobile applications due to its reduced on-resistance, improved temperature coefficient of resistance and reduced gate charge and input capacitance. In this research, we investigated the detailed characteristics of FITMOS devices, developed the SPICE model for simulation and explored their applications in the design of automotive power electronics. Specifically, we identified how to best utilize the FITMOS characteristics to benefit power circuit design and on quantifying the gains that can be achieved through their use. We also expose a previously unrecognized phenomenon in the FITMOS MOSFET. In particular, we show that the on-state resistance of the device depends on both frequency and on peak di/dt at a given frequency. This dynamic on resistance variation can have a significant application impact.<br>by Wei Li.<br>S.M.
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Hempel, Marek Ph D. Massachusetts Institute of Technology. "Technology and applications of 2D materials in micro- and macroscale electronics." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/130201.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, May, 2020<br>Cataloged from student-submitted PDF of thesis.<br>Includes bibliographical references (pages 198-209).<br>Over the past 50 years, electronics has truly revolutionized our lives. Today, many everyday objects rely on electronic circuitry from gadgets such as wireless earbuds, smartphones and laptops to larger devices like household appliances and cars. However, the size range of electronic devices is still rather limited from the millimeter to meter scale. Being able to extend the reach of electronics from the size of a red blood cell to a skyscraper would enable new applications in many areas including energy production, entertainment, environmental sensing, and healthcare. 2D-materials, a new class of atomically thin materials with a variety of electric properties, are promising for such electronic systems with extreme dimension due to their flexibility and ease of integration. On the macroscopic side, electronics produced on thin films by roll-to-roll fabrication has great potential due to its high throughput and low production cost. Towards this end, this thesis explores the transfer of 2D-materials onto flexible EVA/PET substrates with hot roll lamination and electrochemical delamination using a custom designed roll-to-roll setup. The transfer process is characterized in detail and the lamination of multiple 2D material layers is demonstrated. As exemplary large-scale electronics application, a flexible solar cell with graphene transparent electrode is discussed. On the microscopic side, this thesis presents a 60x60 [mu]m² microsystem platform called synthetic cells or SynCells. This platform offers a variety of building blocks such as chemical sensors and transistors based on molybdenum disulfide, passive germanium timers, iron magnets for actuation, as well as gallium nitride LEDs and solar cells for communication and energy harvesting. Several system-level applications of SynCells are explored such as sensing in a microfluidic channel or spray-coating SynCells on arbitrary surfaces.<br>by Marek Hempel.<br>Ph. D.<br>Ph.D. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science
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Marletta, Vincenzo. "FERROELECTRIC E-FIELD SENSORS, A nonlinear dynamic approach to the development of innovative measurement devices." Thesis, Universita' degli Studi di Catania, 2011. http://hdl.handle.net/10761/353.
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The exploitation of nonlinear dynamics behavior in ferroelectric material toward the realization of innovative transducers for the detection of weak and low frequency electric fields is the focus of this thesis.
A nonlinear dynamical system based on ferroelectric capacitors coupled into a unidirectional ring circuit is considered with particular interest for developing novel electric field sensors.
The focused approach is based on the exploitation of circuits made up by the ring connection of an odd number of elements containing a ferroelectric capacitor, which under particular conditions exhibits an oscillating regime of behavior. For such a device a weak, external, target electric field interacts with the system thus inducing perturbation of the polarization of the ferroelectric material; this, the target signal can be indirectly detected and quantified via its effect on the system response. The conceived devices exploit the synergetic use of bi-stable ferroelectric materials, micromachining technologies that allow us to address charge density amplification, and implement novel sensing strategies based on coupling non-linear elemental cells.
Advanced simulation tools have been used for modeling a system including electronic components and non linear elements as the conceived micro-capacitors. Moreover, Finite Element Analysis (FEM) has allowed us to steer the capacitor electrodes design toward optimal geometries and to improve the knowledge of effects of the external target E-field on the electric potential acting on the ferroelectric material.
An experimental characterization of the whole circuit, including three cells coupled in a ring configuration has also been carried out.
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Kotte, Hari Babu. "High Speed (MHz) Switch Mode Power Supplies (SMPS) using Coreless PCB Transformer Technology." Licentiate thesis, Mittuniversitetet, Institutionen för informationsteknologi och medier, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-13964.
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The most essential unit required for all the electronic devices is the Power Supply Unit (PSU). The main objective of power supply designers is to reduce the size, cost and weight, and to increase the power density of the converter. There is also a requirement to have a lower loss in the circuit and hence in the improvement of energy efficiency of the converter circuit. Operating the converter circuits at higher switching frequencies reduces the size of the passive components such as transformers, inductors, and capacitors, which results in a compact size, weight, and increased power density of the converter. At present the switching frequency of the converter circuit is limited due to the increased switching losses in the existing semiconductor devices and in the magnetic area, because of increased hysteresis and eddy current loss in the core based transformer. Based on continuous efforts to improve the new semi conductor materials such as GaN/SiC and with recently developed high frequency multi-layered coreless PCB step down power transformers, it is now feasible to design ultra-low profile, high power density isolated DC/DC and AC/DC power converters. This thesis is focussed on the design, analysis and evaluation of the converters operating in the MHz frequency region with the latest semi conductor devices and multi-layered coreless PCB step-down power and signal transformers. An isolated flyback DC-DC converter operated in the MHz frequency with multi-layered coreless PCB step down 2:1 power transformer has been designed and evaluated. Soft switching techniques have been incorporated in order to reduce the switching loss of the circuit. The flyback converter has been successfully tested up to a power level of 10W, in the switching frequency range of 2.7-4 MHz. The energy efficiency of the quasi resonant flyback converter was found to be in the range of 72-84% under zero voltage switching conditions (ZVS). The output voltage of the converter was regulated by implementing the constant off-time frequency modulation technique. Because of the theoretical limitations of the Si material MOSFETs, new materials such as GaN and SiC are being introduced into the market and these are showing promising results in the converter circuits as described in this thesis. Comparative parameters of the semi conductor materials such as the vi energy band gap, field strengths and figure of merit have been discussed. In this case, the comparison of an existing Si MOSFET with that of a GaN MOSFET has been evaluated using a multi-layered coreless PCB step-down power transformer for the given input/output specifications of the flyback converter circuit. It has been determined that the energy efficiency of the 45 to 15V regulated converter using GaN was improved by 8-10% compared to the converter using the Si MOSFET due to the gate drive power consumption, lower conduction losses and improved rise/fall times of the switch. For some of the AC/DC and DC/DC applications such as laptop adapters, set-top-box, and telecom applications, high voltage power MOSFETs used in converter circuits possess higher gate charges as compared to that of the low voltage rating MOSFETs. In addition, by operating them at higher switching frequencies, the gate drive power consumption, which is a function of frequency, increases. The switching speeds are also reduced due to the increased capacitance. In order to minimize this gate drive power consumption and to increase the frequency of the converter, a cascode flyback converter was built up using a multi-layered coreless PCB transformer and this was then evaluated. Both simulation and experimental results have shown that with the assistance of the cascode flyback converter the switching speeds of the converter were increased including the significant improvement in the energy efficiency compared to that of the single switch flyback converter. In order to further maximize the utilization of the transformer, to reduce the voltage stress on MOSFETs and to obtain the maximum power density from the power converter, double ended topologies were chosen. For this purpose, a gate drive circuitry utilising the multi-layered coreless PCB gate drive transformer was designed and evaluated in both a Half-bridge and a Series resonant converter. It was found that the gate drive power consumption using this transformer was less than 0.8W for the frequency range of 1.5-3.5MHz. In addition, by using this gate drive circuitry, the maximum energy efficiency of the series resonant converter was found to be 86.5% with an output power of 36.5W.
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Senki, Adel. "Development of a Windows(TM) three-dimensional sound system using binaural technology." Thesis, University of Ottawa (Canada), 2000. http://hdl.handle.net/10393/9410.
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It is anticipated that 3-D sound will become a major component in virtual reality environments. In this thesis, we investigate the development of a Windows(TM) 3-D sound system using binaural technology. This work should eventually be integrated in complex virtual environment software. The 3-D sound effects are achieved by applying a filter pair representing audio cues from a specific point in space to the left and right channels of headphones. As a first step, an offline 3-D audio file generation system is developed, and effects such as sound reflections in a virtual rectangular room are added to this system. The real-time implementation is considered next. The first approach tested for the real-time implementation uses the time domain convolution of a sound source signal with head-related transfer functions, but the computational load of this approach is such that it cannot run in real-time at audio sampling rates. As an alternative, a second approach with a Fast Fourier Transform overlap and save technique is used to reduce the computational load, and a real-time implementation at audio frequencies is therefore successfully achieved.
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Umraiya, Anurag. "Design of miniaturized coil system using MEMS technology for eye movement measurement." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66669.
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Application of eye movement measurement is especially significant in Neuroscience. Results from eye tracking can give valuable insight into the correlation between neural activity and eye movements. Abnormalities in the eye movements also provide information regarding diagnosis and progress of neurological diseases such as dementia. Another application is in developing human-computer interfaces as a means of communication for the severely handicapped. Although there are numerous eye tracking techniques available, the magnetic search coil method has been prominently used by researchers due to its high accuracy and precision. This technique typically requires the subjects head to be fixed for accurate measurements due to the use of large field coils. Here we propose a miniaturized coil system using MEMS technology for application in eye movement measurement. The coils were designed and modeled using CoventorWare and MagNet software. The microcoils were then fabricated in the McGill Nanotools microfabrication laboratory. We present the results for using the materials Indium Tin Oxide (ITO) and Aluminium for the fabrication of coils. We found that the resulting coil system is capable of identifying displacements along the X, Y and Z axis. The resolution of the system depends on the configuration of the system, it was calculated to be around 20-40 μm on the plane of the coil and it increases near the centre of the coil. Although the proposed coil system holds significant potential, but further exhaustive testing needs to be performed in an environment simulating eye movements.<br>O Mesurer avec précision les mouvements oculaires constitue un élément essentiel dans ledomaine de la neuroscience. Par exemple, capter les mouvemets de l'oeil contribue à la compréhension de la relation entre les activités neuronales et le comportement oculaire. De meme, les irrégularités observées dans les mouvements des yeux aident à diagnostiquer et à surveiller le progrès de plusieurs troubles mentaux comme la démence. En plus, le tracement de la trajectoire oculaire peut être utilisé pour construire des interfaces homme-machine pour les personnes sévèrement handicapées.Bien que plusieurs techniques de tracement oculaire existent déjà, la bobine de recherche magnétique est fortement utilisée par les chercheurs. Elle offre une haute exactitude et une très bonne précision de mesure. La technique traditionnelle exige l'utilisation de grandes bobines de champs, nécessitant ainsi que la tête du sujet soit fixée en tout temps. En revanche, on propose l'utilisation d'un système de bobines miniaturisées construit avec la technologie MEMS. Les bobines ont été conçues à l'aide des logiciels CoventorWare et MagNet. Les micro-bobines ont été fabriquées dans le laboratoire de micro-fabrication Nanotools de l'Université McGill. On présente les résultats obtenus en utilisant des micro-bobines construites avec la solution solide de l'oxyde de l'étain et l'oxyde de l'indium (ITO). Le système de micro-bobine est capable d'identifier les déplacements dans les trois dimensions X, Y, et Z. La résolution du système dépend de la configuration utilisée. On a trouvé que la résolution peut être entre 20 et 40 μm. Le système proposé est très promettant mais plusieurs tests exhaustifs deraient encore être appliquées dans des environnements qui simulent de vrais mouvements oculaires.
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Koehly, Rodolphe. "Fabrication of sustainable resistive-based paper touch sensors: Application to music technology." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104691.
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Building novel Digital Music Instruments (DMIs) requires the use of a variety of sensors to transduce human actions to electronic signals that will control sound synthesis variables. Among them, contact (force/pressure) sensors such as the Force Sensing Resistors (FSR) are the most commonly used in the design of DMIs. Similar commercial sensor designs based on conductive materials also enable to detect position, displacement or flexion. Unfortunately, although commercial sensors can be easily found at electronic resellers, only a few standardised models with predefined sizes, shapes and electric characteristics can be purchased. Moreover, the quality of the sensor appears to depend on their shape and dimension. These limitations have direct implications on the design of novel DMIs, which actually need to be adapted to the existing offer of commercial sensors. After various investigations with polymers, textiles, adhesives and glues, we finally chose to focus on conductive paper as a generic material for producing sustainable, flexible and customisable contact sensors. This thesis study presents two directions on paper sensors investigations: We first began by studying the potential of building paper contact sensors using industrial paper. This type of paper is originally produced to provide optimal colour properties and is not optimised for use as a conductive material. Nevertheless, it has been shown that it provides a very efficient choice for the design of custom sensors. Several sensor prototypes were built using samples of four industrial papers from three main manufacturers (ArjoWiggins (Canson), Fabriano, and PASCO) and have been used in the design of various gesture controllers. In order to verify the electrical behaviour of these prototypes, we developed a special test machine that enabled us to characterise the sensor's properties in terms of repeatability, drift and hysteresis, and to compare the results with commercial sensors. The second step was to consider how to produce such a paper. Laboratory experiments were performed to evaluate the influence of the papermaking process as well as the chemicals to be added to optimise the retention and formation of a uniform mix of pigments and fibres, enabling the fabrication of a rough, porous, compressible but still elastic material. Papers with various amounts of pigment and different sheet structures were made and characterised in order to evaluate the influence of the paper characteristics onto their electrical resistance. Resulting materials were also characterised with the test machine and compared to other types of resistive materials. This research contributes to the promotion of alternative solutions for the development of contact sensors. In particular, it shows that conductive paper and inks are an ecological alternative to conducting polymers for producing custom contact sensors. Paper sensors can replace industrial sensors in many applications, as they are equally efficient. Moreover they are recyclable or reusable, flexible and customisable, therefore extending the capabilities of industrial solutions. The production of such a paper will provide researchers with raw materials to produce their own sensors and realise new DMIs, such as the ones presented in this thesis. Apart from their usefulness in acquiring expert musical gestures, paper sensors have potential applications in many other fields such as medical (e.g. as hospital bed sheet), security (e.g. sensitive floors), intelligent packaging, etc. Multi-disciplinary research is a profitable way for creating new technological outputs. Conductive paper can provide new ways of building DMIs at moderate cost and with an environmental-friendly label. Music and arts can in return offer an efficient and sensitive proof-of-work to convince industries that conductive papers have a major potential in other applications.<br>La fabrication de nouveaux instruments musicaux numérique (IMN) nécessite l'utilisation de plusieurs types de capteurs afin de convertir les actions humaines en signaux électroniques pour le contrôle de variables de synthèse sonore. Parmi eux les capteurs de contact (force/pression) tels que les "Force Sensing Resistors" (FSR) sont les capteurs les plus utilisés. Même si des capteurs commerciaux peuvent facilement êtres trouvés chez des détaillants en électronique, seul un nombre limité de modèles standardisés, avec des tailles, des formes et des caractéristiques électriques prédéfinies, peuvent êtres achetés. Ces limitations ont des conséquences directes sur le design de nouveaux IMN qui doivent ainsi se limiter aux offres commerciales existantes.Après divers essais utilisant des polymères souples, des textiles, et des colles, nous avons choisi de nous concentrer sur les papiers conducteurs comme matières premières pour produire des capteurs de contact sensibles et adaptables. Ces recherches de thèse se sont alors orientées vers deux directions.Premièrement, nous avons commencé par fabriquer des capteurs à partir de papiers industriels à l'origine produit pour fournir des papiers colorés, et non pour une utilisation en tant que matériau conducteur. Nous avons montré néanmoins que ce papier conducteur est un matériaux sensible et exploitable. Plusieurs prototypes de capteurs ont ainsi été fabriqués en utilisant des échantillons de quatre types de papiers industriels provenant de trois manufacturiers (ArjoWiggins (Canson), Fabriano et PASCO). Ces prototypes ont ensuite été utilisés pour le développement de divers contrôleurs gestuels. Afin de vérifier le comportement des capteurs en action, nous avons développé un banc d'essai permettant de caractériser les propriétés électriques de ces capteurs en termes de répétabilité, dérive et hystérésis, et de les comparer à ceux des capteurs commerciaux.La seconde direction consistait à rechercher comment produire de tels papiers. Des expériences de laboratoires ont permis d'évaluer réglages des processus de fabrication à privilégier et les additifs chimiques à ajouter pour optimiser la rétention et la formation d'un mélange uniforme de pigments et de fibres et la formation d'un papier rugueux, poreux et compressible mais toujours élastique. Plusieurs types de papiers ont été réalisés en faisant varier la quantité de pigments et la structure des feuilles afin d'évaluer l'influence des caractéristiques d'un papier sur sa résistance électrique. Cette recherche contribue à la promotion de solutions alternatives pour le développement de capteurs de contact. Elle montre en particulier que les papiers conducteurs et les encres conductrices sont une alternative écologique aux polymères conducteurs pour la production de capteurs de contact. Les capteurs en papiers peuvent remplacer les capteurs industriels dans de nombreuses applications. De plus, ils sont recyclables et adaptables à tous types de design. La production d'un tel papier va procurer un stock de matières premières aux chercheurs afin qu'ils produisent leurs propres capteurs et conçoivent de nouveaux IMN tels que ceux qui sont présentés dans cette thèse. De plus, mis à part leurs capacités pour le contrôle de gestes musicaux experts, les capteurs en papier ont des applications potentielles dans d'autres domaines tels qu'en médecine (monitoring de lits d'hôpitaux), sécurité et domotiques (sols et murs sensibles), emballages intelligents, etc…La recherche multidisciplinaire est un moyen susceptible de générer de nouvelles technologies. Le papier conducteur offre de nouveaux moyens de produire des IMN pour un coût modéré en plus d'un label environnemental. La musique et les arts permettent en retour d'offrir une application ludique, attirante qui à fait ses preuves afin de convaincre les industries que les papiers conducteurs ont un gros potentiel dans d'autres applications.
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Howe, Daniel S. "Electronics and Communication Technology for a Surface Stimulation Device." Case Western Reserve University School of Graduate Studies / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1222456488.
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Al-Khalidi, Abdullah Koutaiba. "Advanced gallium nitride technology for microwave power amplifiers." Thesis, University of Glasgow, 2015. http://theses.gla.ac.uk/6785/.
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Gallium nitride (GaN) based technology has been heavily researched over the past two decades due to its ability to deliver higher powers and higher frequencies that are demanded by the market for various applications. One of GaN’s main advantages lies in its ability to form heterojunctions to wider bandgap materials such as Aluminium Gallium Nitride (AlGaN) and Aluminium Nitride (AlN). The heterostructure results in the formation of the so called 2 dimensional electron gas (2DEG), which exhibits high electron densities of up to 6E13 cm−2 and high electron mobilities of up to 2000 cm2/V·s that enable the devices to support high current densities. Furthermore, it supports very high breakdown fields of 3.3 MV/cm due to its wide bandgap of 3.4 eV. The main objective of this work was to further advance the transistor technology using simple, cost effective and reliable techniques. The AlN/GaN material system exhibits higher sheet carrier concentrations compared to the conventional ternary AlGaN barrier, but introduces additional challenges due to its reduced thickness of 2-6 nm compared to 18-30 nm of AlGaN. The additional challenges of the thin AlN binary barrier include strain relaxation, high gate leakage currents and high Ohmic contact resistances due to its high bandgap of 6.2 eV. In this work, a thin (5 nm) in-situ SiNx passivation layer was employed to reduce the strain relaxation, reduce gate leakage currents and improve Ohmic contacts resistances. The optimised Ohmic contact annealing condition resulted in an Ohmic contact resistance of 0.4 Ω·mm and a sheet resistance of 300 Ω/
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Thorell, Alexander, and Jonas Cederberg. "Designing a Hyperbolic Lens Antenna using 3D Printing Technology." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-293894.
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To increase capacity, lower latency, and boostdata rates, new higher gain antennas that can transmitmillimeter-waves are needed. Dielectric lens antennas arean attractive potential solution. The J1-project investigatedthe permittivity and losses of four 3D printing filamentsin four frequency bands, to better design a hyperboliclens antenna in the Ka-band with a WR-28 StandardGain Horn Antenna acting as a feed. To measure thedielectric filaments, the TRL calibration method wasevaluated in simulation and employed in measurementstogether with the NRW method for permittivity extraction.Shortcomings of these methods near resonant frequencieswere marginally analyzed in simulation, and the results ofthe processed measured permittivities were shown to havesignificant uncertainty in the loss tangent. Nevertheless thedatasheet specified<(r) =3 was shown to have meanrelative permittivity∗r= 3.53−0.13jin the Ka-band.Using the measurement data, a hyperbolic lens antennawas designed and optimized in simulation for the centerfrequency of the Ka-band at 33.25 GHz. The simulatedresults show an aperture efficiency of 36.2% and a gainof 30.4 dBi.<br>För att öka kapaciteten, sänka för- dröjningen samt höja datahastigheterna så behövs högre förstärkta antenner som kan transmittera millimetervågor. Här är dielektriska linsantenner en attraktiv, potentiell lösning. J1-projektet undersökte permittiviteten och förlusterna av fyra 3D-utskriftsfilament i fyra frekvensband, för att bättre designa en hyperbolisk linsantenn i Ka- bandet för en matande WR-28 “Standard Gain Horn Antenna”. För att kunna mäta de dielektriska filamenten så var TRL-kalibreringsmetoden utvärderad i simulering och nyttjad vid mätning tillsammans med NRW-metoden för att betsämma permittiviteten. Nackdelarna bakom dessa metoder nära resonanta frekvenser var marginellt analyserade i simulering och resultaten av de behandlade, mätta permittiviteterna visade sig ha märkbara osäker- heter i deras förlusttangens. Oavsett så blev medelvärdet på det uppmätta resultatet; av det databladsspecificerade materialet R (∈r) = 3; ∈*r = 3,53 -0,13j i Ka-bandet. Med hjälp av databladsspecifikationerna, så designades samt optimiserades en hyperbolisk linsantenn i simulering för Ka-bandets mittfrekvens på 33,25 GHz. De simulerade resultaten visar på en apertureffektivitet på 36,2% och en förstärkning på 30,4 dBi.<br>Kandidatexjobb i elektroteknik 2020, KTH, Stockholm
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Moran, David A. J. "Self-aligned short gate length III-V HEMT technology." Thesis, University of Glasgow, 2004. http://theses.gla.ac.uk/6577/.
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This thesis presents a ne- approach to the fabrication of short gate length HI-V High Electron Mobility Transistors (HEMTs) that reduces the impact of external parasitic elements, and in particular access resistances, upon device performance. This was approached through the development of a self-aligned T-gate process with non-annealed ohmic contacts. The process was used to fabricate both GaAs pseudomorphic HEMT and subsequently lattice matched InP devices. In addition, a new selective recess etch was developed for cap layers containing indium. Characterisation of the self-aligned GaAs pHEMT devices indicated good RF performance with fT = 137GHz and fmax = 182GHz for devices of 120nm gate length, although DC performance was found to be restricted by the unoptimised non-annealed ohmic process. Analysis of the operation of the GaAs pHEMT devices led to the design and growth of an InP material structure incorporating double delta doping to minimise the non-annealed ohmic contact resistance. Using this optimised structure, standard and self-aligned HEMT devices with gates of length 120nm and 70nm were fabricated for comparison. The benefits and limitations of the self-aligned process were highlighted by comparing the performance of the self-aligned and standard devices. The self-aligned 120nm devices had fT = 220GHz and fmax = 255GHz, which rose to fT = 270GHz and fmax = 300GHz for the 70nm devices. Transconductance figures of up to 1500mS/mm were extracted for both. It is concluded that the self-aligned process, although beneficial to device performance at the 120nm, and to a lesser degree the 70nm node, would begin to degrade performance at reduced gate lengths due to increased parasitic gate capacitances. The non-annealed ohmic technology developed in this work provides a route that minimises parasitic resistances and increases performance without the increased parasitic gate capacitances associated with a self-aligned gate approach. A possible solution for the minimisation of parasitic gate capacitances using a self-aligned approach is proposed.
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Gupta, Shoubhik. "Ultra-thin silicon technology for tactile sensors." Thesis, University of Glasgow, 2019. http://theses.gla.ac.uk/41053/.
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In order to meet the requirements of high performance flexible electronics in fast growing portable consumer electronics, robotics and new fields such as Internet of Things (IoT), new techniques such as electronics based on nanostructures, molecular electronics and quantum electronics have emerged recently. The importance given to the silicon chips with thickness below 50 μm is particularly interesting as this will advance the 3D IC technology as well as open new directions for high-performance flexible electronics. This doctoral thesis focusses on the development of silicon-based ultra-thin chip (UTC) for the next generation flexible electronics. UTCs, on one hand can provide processing speed at par with state-of-the-art CMOS technology, and on the other provide the mechanical flexibility to allow smooth integration on flexible substrates. These development form the motivation behind the work presented in this thesis. As the thickness of any silicon piece decreases, the flexural rigidity decreases. The flexural rigidity is defined as the force couple required to bend a non-rigid structure to a unit curvature, and therefore the flexibility increases. The new approach presented in this thesis for achieving thin silicon exploits existing and well-established silicon infrastructure, process, and design modules. The thin chips of thicknesses ranging between 15 μm - 30 μm, were obtained from processed bulk wafer using anisotropic chemical etching. The thesis also presents thin wafer transfer using two-step transfer printing approach, packaging by lamination or encapsulation between two flexible layerand methods to get the electrical connections out of the chip. The devices realised on the wafer as part of front-end processing, consisted capacitors and transistors, have been tested to analyse the effect of bending on the electrical characteristics. The capacitance of metal-oxide-semiconductor (MOS) capacitors increases by ~5% during bending and similar shift is observed in flatband and threshold voltages. Similarly, the carrier mobility in the channel region of metal-oxide-semiconductor field effect transistor (MOSFET) increases by 9% in tensile bending and decreases by ~5% in compressive bending. The analytical model developed to capture the effect of banding on device performance showed close matching with the experimental results. In order to employ these devices as tactile sensors, two types of piezoelectric materials are investigated, and used in extended gate configuration with the MOSFET. Firstly, a nanocomposite of Poly(vinylidene fluoride-co-trifluoroethylene), P(VDF-TrFE) and barium titanate (BT) was developed. The composite, due to opposite piezo and pyroelectric coefficients of constituents, was able to suppress the sensitivity towards temperature when force and temperature varied together, The sensitivity to force in extended gate configuration was measured to be 630 mV/N, and sensitivity to temperature was 6.57 mV/oC, when it was varied during force application. The process optimisation for sputtering piezoelectric Aluminium Nitride (AlN) was also carried out with many parametric variation. AlN does not require poling to exhibit piezoelectricity and therefore offers an attractive alternative for the piezoelectric layer used in devices such as POSFET (where piezoelectric material is directly deposited over the gate area of MOSFET). The optimised process gave highly orientated columnar structure AlN with piezoelectric coefficient of 5.9 pC/N and when connected in extended gate configuration, a sensitivity (normalised change in drain current per unit force) of 2.65 N-1 was obtained.
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Chuah, Alan E. L. "Design and implementation of high-speed transmitters and receivers for optical interconnects in CMOS technology." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33964.
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Optoelectronic very-large scale integrated (OE-VLSI) technology provides for the integration of photonic devices, such as the laser-diode and the photodiode, with silicon VLSI electronics. This technology is capable of providing high bandwidth and high-density optical input/output (I/O) to silicon VLSI chips, with an aggregate data bit rate of over a Terabit per second. The development of the vertical-cavity surface-emitting laser (VCSEL) and the high-speed p-i-n photodiode has made this technology possible. Optical transmitter and receiver circuits are responsible for the interfacing between the photonic devices and the silicon VLSI electronics. This thesis presents designs of optical transmitter and receiver circuits implemented in a 0.18 mum CMOS technology. These circuits are designed to achieve minimum power consumption and circuit area, and maximum high-speed performance. Different circuit topologies are studied and implemented. Three different topologies of laser drivers for transmitter and two different preamplifiers for receivers are studied and presented in this thesis.
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Koutrakou, Vassiliki N. "National and European collaborative programmes in information technology research in the 1980's." Thesis, University of Kent, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317659.
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Heim, Gregory R. "Management of technology and quality in electronic consumer service operations : applications to electric food retailing /." Diss., ON-CAMPUS Access For University of Minnesota, Twin Cities Click on "Connect to Digital Dissertations", 2000. http://www.lib.umn.edu/articles/proquest.phtml.
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Elzagzoug, Ezzaldeen. "Chromatic monitoring of transformer oil condition using CCD camera technology." Thesis, University of Liverpool, 2013. http://livrepository.liverpool.ac.uk/12233/.
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Power transformers are essential components within the power distribution system. Transformer failures having a high economic impact on the distribution operators and the industrial and domestic customers. Dielectric mineral oil is used in transformers for electrical insulation between live parts, cooling and protection of the insulation papers in the transformer. Oil contamination and changes in the chemical structure of the oil result in the decay of insulation paper and reduced insulation and cooling which can lead to a transformer failure. The general approach to oil monitoring has been for an operator to examine the colour index (ASTM) of the oil, electrical strength, acidity, water contents and dissolved gas analysis results and form an opinion as to the extent of oil degradation. Chromatic techniques enable data from di↵erent sources to be combined to give an overall evaluation about the condition of a system being monitored. One of the main goals for this work was to use chromatic techniques for integrating the oil data from the di↵erent sources and sensors. In addition the chromatic approach enables liquids to be monitored optically so a second aim was to apply chromatic optical oil monitoring using portable system by transmitting polychro- matic light through the oil sample, which is contained in a transparent cuvette and imaged using a mobile phone camera. A number of oil samples were optically analysed with portable chromatic sys- tem and the optical data was compared with the colour index and chromatically companied with the dissolved gas and other oil data to give overall evaluation of oil degradation. The chromatic optical result compared favourably with the colour index. It was also possible to classify the oil samples chromatically into categories of low, medium and high degradation. This enabled the chromatic data combination approach to be implemented as a prototype system in Matlab software that an operator could use to get a classification of an oil sample. Essential experiment was introduced to monitor di↵erent oil particles by obtaining the result of di↵erent filtered samples through the filter paper. Beside the ability to analyse data and distinguish between fresh and contam- inated oil samples the chromatic technique has the ability to track the history of di↵erent degraded oil samples which can give an indication about failure faults and it could give a prediction of any future faults. Therefore a commercially viable reliable system can be developed to extend the service life and extend the maintenance schedules. These monitoring systems could lead to extending the service life of the transformers, making the electricity supply more reliable and giving the consumer a better quality of life.
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Mahmud, Akib. "Hardware in the Loop (HIL) Rig Design and Electrical Architecture." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-324661.
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Different types of machines are tested utilizing so called Hardware In the Loop simulation. To perform HIL-simulation a rig is used consisting of different types of hardware and software. Some of the hardware that are used during a simulation is located inside an EMS box. The box has not been properly updated since 2004, no documentation of changes has been made and often many errors occurs during simulations due to the lack of traceability. During this project a new structure of the EMS box has been designed with modifications to eliminate existing problems, prevent similar problems to occur in the future and improve the usability of the system. A simulation was performed on the camshaft to test if there were any improvements. Most issues were solved but there were one problem that remained. Some noises existed and were rooted in the old box which undeniably remained in the new one.
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Khalil, Ashraf F. "Networked control of distributed energy systems." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3380/.
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This thesis reports a new method for stability analysis and maximum time delay estimation in networked control systems with applications to distributed energy systems. The proposed new method is based on using finite difference approximation for the delay term and then the Lyapunov system stability theorem is applied to derive the time delay boundary allowed to the system. The proposed method has been applied to networked control systems with state feedback controllers, with dynamic controllers, and to multi-units interconnected networked control systems. The proposed method is then extended to a class of networked control system with bounded nonlinearity and uncertainties. It is found that increasing the nonlinearity in the system will result in decreasing the maximum allowable time delay. Compared with most of the methods reported in the published literature, the new method is simple to use while the results are comparable. When the time delay is modelled using Markov Chain the stability of the networked control system is formulated as finding the solutions for Bilinear Matrix Inequalities. An improved V-K iteration algorithm is used to solve the Bilinear Matrix Inequalities in order to derive a controller to stabilize the systems.
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Hu, Hongwei. "Towards an improved model of dynamics for speech recognition and synthesis." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3704/.
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This thesis describes the research on the use of non-linear formant trajectories to model speech dynamics under the framework of a multiple-level segmental hidden Markov model (MSHMM). The particular type of intermediate-layer model investigated in this study is based on the 12-dimensional parallel formant synthesiser (PFS) control parameters, which can be directly used to synthesise speech with a formant synthesiser. The non-linear formant trajectories are generated by using the speech parameter generation algorithm proposed by Tokuda and colleagues. The performance of the newly developed non-linear trajectory model of dynamics is tested against the piecewise linear trajectory model in both speech recognition and speech synthesis. In speech synthesis experiments, the 12 PFS control parameters and their time derivatives are used as the feature vectors in the HMM-based text-to-speech system. The human listening test and objective test results show that, despite the low overall quality of the synthetic speech, the non-linear trajectory model of dynamics can significantly improve the intelligibility and naturalness of the synthetic speech. Moreover, the generated non-linear formant trajectories match actual formant trajectories in real human speech fairly well. The \(\char{cmmi10}{0x4e}\)-best list rescoring paradigm is employed for the speech recognition experiments. Both context-independent and context-dependent MSHMMs, based on different formant-to-acoustic mapping schemes, are used to rescore an \(\char{cmmi10}{0x4e}\)-best list. The rescoring results show that the introduction of the non-linear trajectory model of formant dynamics results in statistically significant improvement under certain mapping schemes. In addition, the smoothing in the non-linear formant trajectories has been shown to be able to account for contextual effects such as coarticulation.
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Zhao, Junwei. "Dynamics of space charge and electroluminescence modelling in polyethylene." Thesis, University of Southampton, 2012. https://eprints.soton.ac.uk/337550/.
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Space charge has been recognized as an important factor contributing to the electrical failure of the cable insulation. Extensive efforts have been made to investigate space charge dynamics within polymeric insulations under electric stresses. Basic information about space charge has been recognized resorting to modern charge mapping techniques but the underlying mechanisms for charge transport, charge trapping characteristics are not yet well understood. Hence theoretical modelling and numerical simulation are employed to simulate the space charge and provide an insight into the charge distribution in dielectrics. This thesis comprises the quantitative analysis of space charge through numerical modelling and experimental investigations of charge trapping in polymeric insulation materials. A bipolar charge transport model which involves bipolar charge injection from the electrodes, charge transport with trapping and recombination in the bulk has been developed to simulate the dynamics of space charge in polyethylene. The build-up of space charge in polyethylene under dc electric fields has been modelled. The influence of parameters related to the properties of polyethylene on the formation of space charge has been recognized. Furthermore, this model is introduced to simulate the dynamics of corona charge decay in polyethylene. The formation of charge packets in polyethylene is also investigated using a numerical modelling approach. A fast pulsed electro-acoustic system along with a data processing program has been developed to investigate the behaviour of space charge in polyethylene under ac voltages. The understanding of space charge under ac stresses has also been simulated using the further developed bipolar charge transport model. Experiments and simulation have also been expanded into understanding electroluminescence, which is an indication of pre-aging of polymers under ac stress.
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Paul, Gordon. "Screen printed textile based wearable biopotential monitoring." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/374177/.
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This thesis describes the development of printed wearable electrode networks on textiles for monitoring human biopotentials from the skin surface. The aim was to fabricate garments to monitor human biopotentials, such as an electrocardiogram (ECG), on a long term basis. A literature review was carried out to examine fabrication methods for wearable electrode networks on textile and screen printing is selected for this work. Several conductive and insulating screen printable pastes were then evaluated for this application and suitable pastes were selected. Screen printing was used to create networks of conductive tracks on the surface of woven textiles. These networks connect electrodes at different sites to electronics at a central location. The conductive tracks are composed of a silver polymer layer with thickness 5-10μm entirely encapsulated in polyurethane. The durability of these printed conductive tracks is investigated with cyclic stress and washing machine tests. A significant improvement in the durability of these tracks is achieved by using two different polyurethane pastes and optimising the screen printed layer structure. Tracks that can reliably endure 10 typical domestic machine washes without breaking are demonstrated. Carbon loaded silicone rubber is stencil printed to form electrodes on exposed conductive pads at the terminations of screen printed conductive tracks. The carbon loaded rubber formulation is optimised to provide electrodes with low resistivity, low surface energy and high flexibility. By using stencil printing rather than screen printing, the thickness of the electrodes is increased, causing them to protrude from the textile surface, which is useful in ensuring stable electrode-skin contact. Passive and active electrodes are fabricated on woven textiles using screen and stencil printing, and their performance is evaluated. The passive electrodes have issues with DC instability, but have suitable performance for some electromyography tasks and basic heart rate monitoring. The active electrodes show comparable performance with the gold standard, commercial Ag/AgCl electrodes. The printed textile electrode networks are demonstrated in four applications: a one-lead bipolar heart monitoring belt, a Frank configuration vector-cardiogram monitoring vest, a headband as an electromyographic (EMG) and electrooculographic (EOG) computer interface, and an armband used to examine electromyographic activity in the upper arm. Screen printing on textiles is shown to be a low-cost alternative fabrication process for durable wearable electrode networks on textiles, capable of providing high signal quality. These printed textile electrode networks are shown to be applicable to ambulatory monitoring, to reduce the associated cost and discomfort, and in hospitals and research to reduce electrode setup time.
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Lin, Han-Hsuan. "Handling of Environmental Related Requirements : Awareness and Ability to Act at Small and Medium Sized Electric and Electronic Companies." Thesis, Linköping University, Environmental Technique and Management, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-53182.
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<p>Environmental related product requirements are increasing worldwide from government authorities, customers and other stakeholders. For small and medium sized companies manufacturing electric and electronic products it is more difficult compared to bigger companies to meet new product related requirements due to smaller budget, resources and knowledge. This research studies the awareness and ability to act upon changes when small and medium sized companies in Sweden face environmental related requirements.</p><p>The result is compared to previous conducted studies in a number of Asian countries. The study has been conducted through face-to-face interviews (12 companies), phone interviews (6 companies), and questionnaires (50 companies). After a preliminary literature study and targeting of objective companies interviews were made at first with the questionnaire study based on results from the interviews. In total, respondents from 68 companies participated in this research. Results from the study reveal that companies both in Sweden and Asia experience the same directives from EU and that WEEE and RoHS have had the biggest impact upon companies. Outside the EU market, companies do not comply with the legislations in the same way. There is a difference in how Swedish companies choose to treat environmental related product requirements as compared to electric and electronic companies in Asia. Furthermore, legislations are a very effective form to affect companies’ environmental work and adaptations, especially if it is imposed directly on the product itself. Both Swedish and Asian companies feel they need more education, more information about environmental related product requirements and more support from government authorities in order to cope with increasing demands from customers and legislations.</p>
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Martin, Christopher. "Development of a bioelectric nerve conduit using solenoid technology, and nano fabrication." Thesis, University of Glasgow, 2013. http://theses.gla.ac.uk/5278/.
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Peripheral nerve repair outcomes have lagged behind comparable surgical techniques for many decades. A number of advanced approaches have been adopted over the last ten years. In particular the application of electrical stimulation during a repair is of great interest. It is clear that electrical stimulation of regenerating nerve tissue has a great many effects and can improve functional outcomes for patients. This work has focused on developing systems capable of applying accurate electric fields on the microscale within a biodegradable conduit, powered wirelessly. Experiments were conducted in vitro with a view to making progress towards an in vivo implementation. Electrical stimulation was applied to regenerating sensory neurons in vitro, from a rat dorsal root ganglion. Mechanical guidance cues aligned neurons towards different microelectrode configurations in order to record the effect of applied electrical stimulation. This was performed using custom stimulation modules. SU-8 microgrooves and Ti/Au electrodes acted as mechanical and electrical cues respectively. This method was employed to great effect, identifying the effect of a number of electrical stimulation parameters. This led to a stimulation protocol featuring a 1:4 duty cycle, 20 mV amplitude, 100 Hz sinusoidal signal. This produced a number of interesting effects, including neuronal turning and a barrier formation. These results, demonstrated at the cellular level using a custom device and an autonomous stimulation system illustrates progress towards an optimised electrical stimulation waveform for neuronal growth control. A novel transfer printing process was developed to produce patterned gold films on the biodegradable polymer, polycaprolactone. Patterned Au, 400 nm thick, was transferred to a sheet of the polymer, producing a 15 turn, spiral inductor. The inductor was then electroplated to a thickness of 30 μm and wire-bonded. Power and data were transferred wirelessly to the receiver circuit. Receiver circuits, connected to stimulation test modules in planar form, delivered electrical stimulation waveforms to regenerating sensory neurons on polycaprolactone. This stimulation resulted in confinement of the cells between two pairs of electrodes, demonstrating the efficacy of the novel receiver circuits. This was achieved with four electrodes in a twin-barrier configuration. These results illustrate progress towards implantation in vivo, using remotely powered electronics to guide regenerating neurons to their targets with microelectrodes. Sensing cell growth through changes in electrical impedance is a well-documented technique. A receiver inductor has been connected to caco-2 cells in culture. Power was transmitted to the receiver inductor through an inductive link. Changes in the cell-monolayer have been detected at the transmitter output circuit, showing that the impedance changes are of sufficient magnitude to be reflected to the transmitter. Trypsin or EDTA were added to confluent layers of caco-2 cells, detaching them from the surface of the microchannel electrode array. This detachment was seen at the transmitter in the form of transient voltage changes. Data was acquired in using Labview programming and PXI hardware systems. This work illustrates progress towards biodegradable, passive cell sensing inspired by radio frequency identification technology, and electric cell impedance sensing.
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Alkhalil, Feras. "Development of novel fabrication technology for SOI single electron transfer devices." Thesis, University of Southampton, 2013. https://eprints.soton.ac.uk/360500/.
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This report presents the design, simulation and fabrication of a spin qubit platform on ultrathin SOI (Silicon-on-Insulator) using A1 FinSET (Single electron transistor) gates and Si side gates. A new design layout is proposed for the double spin qubits co-integrated with a single electron electrometer, a waveguide and a nanomagnet. This platform aims to demonstrate the full operation of double spin qubits by integrating the following three key techniques in one compact footprint: a precisely controlled single electron transfer technology, a high speed charge detection technique and a single spin detection technology based on spin to charge conversion. A single electron transfer device (SETD) integrated with an electrometer is introduced here as the main building block of the spin qubit platform. The single electron transfer device consists of three nanowire (MOSETs) connected in series, and is capacitively coupled to an SET electrometer. A unique layout design for the SETD and a novel single electron transfer voltage pulse sequence are introduced. Simulation and dynamic analysis of this device operation are preformed using a finite element capacitance based simulation method and a Monte Carlo based single electron circuit simulation. The simulations demonstrated the ability of this platform to transfer single electrons and these characteristics are analyzed to optimize the layout. A novel fabrication process to realize high density silicon quantum dots (QDs) with A1 FinSET gates and close proximity Si gates on ultrathin SOI, for single electron transfer and detection, is successfully established with a number of different device layouts realized. In these devices, A1 FinSET gates surround an SOI nanowire channel forming electrically tunable potential barriers and defining QDs among them; Si plunger side gates are included to enable precise control of the QDs potential. Five SETD and electrometer device generations have been realized, tested and analyzed to improve the device yield; this extensive process development work is concluded with a novel fabrication approach to demonstrate successful FinSET A1 gae technology for SOI nanowires. This QDs platform is fabricated using a multi-layer electron beam lithography process that is fully compatible with metal oxide semiconductor technology. The fabrication process is fully developed with a yield of 92% and a great flexibility to enable the realization of more complex structures and even for devices beyond the scope of this project as shown in the appendices of this report.
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McGillan, Glen. "The design of an electric fence fault-finder : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Engineering in Computer Systems Engineering at Massey University, Albany, New Zealand." Massey University, 2009. http://hdl.handle.net/10179/1161.
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Electrified fencing is commonly used throughout the world to control animals with smaller and cheaper fence constructions than would otherwise be necessary with non-electrified wires. Typical installations have a long wire or wires starting from an electric fence energiser and then surrounding fields in various complex configurations. Faults on electric fences can be difficult to locate, with the average fence using tens of kilometres of wire. Basic fault-finding tools allow an operator to read the peak fence voltage, requiring the user to decide whether a fault is present and to randomly search for the source of the problem. The focus of this thesis is to develop a device that reduces the time to locate faults on a fence by providing more information about the location and nature of a fault, and will point in the direction of the fault.
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Cherrington, Ruth. "Towards the low cost manufacture of dye-sensitized solar cells using inkjet technology." Thesis, University of Warwick, 2016. http://wrap.warwick.ac.uk/81883/.
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This work presents a novel means of producing dye-sensitized solar cells (DSSCs), using an inkjet printing technique. To manufacture a completely inkjet-printed DSSC, all layers must be considered and a thorough analysis of the suitability of the printing process has previously been unreported. For DSSCs to become commercially viable they must have long term operational stability, be efficient, have a low environmental impact and low manufacturing cost. Inkjet printing is an additive manufacturing process, meaning that material is only deposited where needed, minimising the material wastage. Several nanoparticle materials were investigated including titanium dioxide (TiO2), carbon black as a low cost replacement for platinum and PEDOT:PSS as a low cost replacement to the widely used spiro-MeOTAD 92,2' ,7,7'-tetrkis(N,N-di-p-methoxyphenylamine)-9,9-spirobifluorene) solid-state hole transport material. A highly porous network of metal-oxide nanocrystals is a fundamental building block to produce DSSCs. The morphology of this layer can greatly influence the efficiency of the cell and therefore a significant amount of this project was spent on developing suitable ink and printing this layer. Titanium dioxide (TiO2) is widely used within the development of photoanodes due to its low cost, stability and low impact on the environment. However, it can be difficult to create a stable dispersion within water due to the natural tendency for the material to agglomerate. An aqueous TiO2 nanoparticle dispersion was developed and several additive materials were explored in an effort to optimize the ink. The initial ink was printed to produce a layer 2.6 μm thick which, once incorporated into a DSSC, resulted in a promising efficiency of 3.50%. Inkjet printed carbon black counter electrodes with thicknesses of 10.24 μm, lead to efficiencies of 2.59%, whilst inkjet printed PEDOT:PSS solid state hole transport material resulted in a very low efficiency of 0.08%. Whilst the PEDOT:PSS and carbon did not produce suitable results for this application, it is suggested that further materials are still investigated due to the benefits of the manufacturing technique. Therefore, it can be concluded that this work shows the capability of inkjet printing for low-cost solar cells, with exciting potential application to other printed electronic applications.
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Sekar, Booma Devi. "Hybrid intelligent technology based fault diagnosis system for squirrel cage induction motor." Thesis, University of Macau, 2007. http://umaclib3.umac.mo/record=b1678023.
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Durairaj, Rajkumar. "Rheological characterisation of solder pastes and isotropic conductive adhesives (ICAs) for microsystems assembly technology." Thesis, University of Greenwich, 2006. http://gala.gre.ac.uk/6153/.
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The printing of solder pastes through very small stencil apertures required for flip-chip pitch sizes, is expected to result in increased stencil clogging and incomplete transfer of paste to the printed circuit board pads. The paste printing process depends on conditions such as good paste roll, complete aperture filling and paste withdrawal. The paste rheology is important in the printing process because the viscosity of the paste must be low enough for the squeegee to force the paste through the stencil apertures, but high enough to recover to its required shape and not flow beyond its stencilled area. Rheological measurements can be used as a tool to study the deformation or flow experienced by the pastes during the stencil printing process. In addition, the rheological measurements can also be used as a quality control tool in the paste production process for identifying batch to batch variation; and to reduce the associated printing defects in the paste printing process. The work reported here on the rheological characterisation of novel pastes used in Microsystems assembly applications is divided into four main parts. The first part concerns the study of the effect of wall slip on paste viscosity measurement. For this study, a novel technique was developed for flow visualisation experiments using video observation to characterise the pastes wall slip behaviour. The second part of the study concerns an investigation of the visco-elastic behaviour of the pastes, and the main focus of the work was to determine the linear visco-elastic region using oscillatory shear stress experiments. The third part of the work deals with the study of the thixotropic behaviour of pastes using both hysteresis loop and constant shear rate tests. The final part of the study concerns the printing trial of three different paste formulations (XP22, Tamura and Polysolder) paste using a UV-LIGA manufactured stencil recently developed at Heriot-Watt University. The work is part of EPSRC funded research project on Microsystems Assembly Technology for the 21st Century under grant GR/R09206/02, and was carried out in collaboration with five industrial collaborators and two other academic partners. The Individual Grant Review (IGR) for the MAT21 project was assessed as internationally leading' by the EPSRC committee. The extensive set of results from the experimental programme, in particular, on the aspect of key paste performance indicators has been adapted by one of the industrial partners (a paste manufacturer) for implementation as part of a quality assurance (QA) tool in their production plants in various part of the world, and the results have also been disseminated widely through journal publications and presentation at international conference.
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Mathieu, Frédérick. "Alignment tolerance study between VCSEL arrays and a new kind of ordered fiber array technology considered for two-dimensional parallel optical interconnects." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0035/MQ64237.pdf.
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Gullipalli, Raashita, and Kiran Kumar Golla. "Arduino-Based Radio Technology System for Bird Protection : Wind Farm Application Approach." Thesis, Blekinge Tekniska Högskola, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-20056.
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Kalhor, Nima. "Development of high yield fabrication technology for graphene quantum dots for single electron transistor applications." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/372746/.
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Since the seminal work by Loss and DiVincenzo, quantum dots (QDs) have been extensively studied as building blocks for quantum information processing (QIP). Presently, the most advanced implementations of QD qubits are realised in III/V heterostructures (GaAs/AlGaAs). However, the strong spin-orbit and hyperfine interactions in these compounds pose fundamental limits to the spin coherence time, and so stimulating the search for alternative host materials. Graphene, a two-dimensional single atomic layer of carbon atoms, was successfully produced for the first time in 2004. Despite its short history, its unique material properties have ensured a rapid growth of interest in several areas of science and technology. Spin-orbit coupling and hyperfine interaction with carbon nuclei are both small in graphene, and a very long spin relaxation length has been demonstrated, which make graphene a promising candidate for quantum information technology and spin qubit embodiment. Superior transport properties of graphene encourage the downscaling of graphene devices to the regime where coherent nature of electronic and spin states can be fully exploited. This requires the development of ultrafine patterning technologies which enables accurate nanoscale fabrication beyond the present electron-beam lithography technique. Therefore, inspired by the on-going trend towards device miniaturization, we present a novel hybrid fabrication method for graphene nano devices (e.g. graphene QDs devices) with minimum feature sizes of ~3 nm (i.e. the gap between the graphene side-gates and channel). Here, for the first time we combine conventional e-beam lithography and direct milling with the sub-nm focused helium ion beam generated by a helium ion microscope to fabricate high resolution graphene QDs devices, reliably and reproducibly. The highly controllable, fine scale fabrication capabilities offered by this approach could lead to a more detailed understanding of the electrical characteristics of graphene quantum devices and pave the way towards room-temperature operable grapheme quantum dot devices.
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Sharabi, Salah-Aldeen. "Extension of 0.18µm standard CMOS technology operating range to the microwave and millimetre-wave regime." Thesis, University of Glasgow, 2015. http://theses.gla.ac.uk/6699/.
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There is an increasing interest in building millimetre-wave circuits on standard digital complementary metal oxide semiconductor (CMOS) technology for applications such as wireless local area networks (WLAN), automotive radar and remote sensing. This stems from the existing low cost, well-developed, high yield infrastructure for mass production. The overall aim of this thesis is to extend the operating range of 0.18um standard logic CMOS technology to millimetre-wave regime. To this end, microwave and millimetre-wave design, optimisation and modelling methodologies for active and passive devices and low noise circuit implementation are described. As part of the evaluation, new systematic and modular ways of making high performance passive and active devices such as spiral inductors, slow-wave coplanar waveguide (CPW) transmission lines, comb capacitors and NMOS transistors are proposed, designed, simulated, fabricated, modelled and analysed. Small-signal and noise de-embedding techniques are developed and verified up to 110 GHz, providing an increased accuracy in the device model, leading to a robust design at millimetre-wave frequencies. Reduced substrate losses resulting in increased quality factor are presented for optimised spiral inductor designs, featuring patterned floating shield (PFS), enabling improved matching network and a reduced chip area. Based on the proposed shielded slow-wave CPW, both the line attenuation and structure length are decreased, resulting in a more compact and simplified circuit design. An optimised transistor design, aimed at reducing the layout parasitic effects, was realised. The optimisation led to a significant improvement in the gain and noise performance of the transistor, extending its operation beyond the cut-off frequency (ft). By combining all the optimised components, low noise amplifiers (LNAs) operating at 25 GHz and 40 GHz were implemented and compared. These LNAs demonstrate state-of-the-art performance, with the 40 GHz LNA exhibiting the highest gain and lowest noise performance of any LNA reported using 0.18um CMOS technology. On the other hand, the 25 GHz LNA showed a comparable performance to other reported results in literature using several topologies implemented in CMOS technology. These findings will provide a framework for expansion to smaller CMOS technology nodes with the view of extending to sub millimetre-wave frequencies.
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Zhou, Yuan. "Electrical properties of mineral oil and oil/impregnated pressboard for HVDC converter transformers." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/376538/.
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Modern power industry requires higher performance dielectric liquids. Mineral oil is one of those most important and widely used insulating materials. Recently, research on the dielectric properties of mineral oil insulation reveal that oil resistivity can greatly influence the field distribution within an oil-pressboard insulation system in a DC field environment, especially during polarity reversals. Basic test methods such as dielectric spectroscopy and polarization and depolarization measurement have already been used to test mineral oil and pressboard conductivity. However, the knowledge about the mechanism of electrical conduction ininsulating oil and pressboard is still limited. Therefore, the goal of this thesis is to gain a better understanding of the mechanism of electrical conduction in mineral oil and oil impregnated pressboard. Polarization and depolarization current method (PDC) has gained huge popularity for insulation diagnosis. This time-dependent measurement may provide sufficient information about the dielectric properties of mineral oil and its electrical performance. Here, the dielectric characteristics of three types of mineral oils with different ageing times have been studied using the PDC method. A new polarization theory involving two kinds of charge carriers have been proposed to explain the dielectric behaviour observed in our measurements. Dielectric spectroscopy is a powerful tool to study dipole relaxation, electrical conduction and structure of molecules. Electrode polarization, as a parasitic effect due to the blocking of charge carriers in the vicinity of an electrode, can make the frequency response at low frequency difficult to understand. Since charge carriers in mineral oil are not only generated from dissociation but also from injection at electrodes, the current induced by the motion of the injected charge carriers should also be taken into consideration. The polarization caused by the injection current has been studied in this thesis. When the electric field is not intense, the injection current is proportional to the field and only contributes to the imaginary part of the complex permittivity. A new computer based calculation method and a modified space charge polarization theory have been proposed with this injection current being involved. The frequency responses of three different kinds of mineral oils have been measured and the experimental results have been compared with the simulation using the modified model. It seems the density of the injected charge carriers increases with the aging period. This new model enables one to gain a better understanding of electrical conduction in mineral oil. The design and choice of an electrode system is important in DC conductivity measurement of insulating liquid. In this thesis, the electric field distribution of an electrode system which consists of two parallel circular metallic electrodes and a guard electrode has been studied using Comsol Multiphysics software. A new parameter which is not yet involved in current standards, the edge radius, has been investigated by means of field calculation. It has been found out that there are regions in the vicinity of the edges of the guard and measuring electrode at which the field is dramatically distorted. If the edges of these two electrodes are sharp, the maximum electric field in the test cell will be much higher than the average field between the measuring electrode and the high voltage electrode. An empirical equation has been proposed to calculate this maximum field. The classic correction expression of effective radius has been re-evaluated with the edge radius being taken into account. Experimental work has been performed to confirm this conclusion. Three kinds of mineral oils with different aging times have been tested under the DC field using a guarded electrode system and the electric strengths of these oils have been estimated. A recommendation has been made to current standards in insulating liquid measurement. The dielectric properties of the oil impregnated pressboard sample have been evaluated with the PDC measurement under different temperatures and electric fields. The classic R-C equivalent model has used to explain the dielectric behaviour of the oil/pressboard sample in our PDC measurement. As the electrode effect should be taken into consideration in a DC field, a modified R-C equivalent model has been proposed and used to fit the experimental results and good fitting has been obtained.