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Pheng, Bobby B. "3D Electromagnetic Simulation Tool Exposure for Undergraduate Electrical Engineers: Incorporation into an Analog Filters Course." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/819.
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With the growth of wireless communications, comes the need for engineers knowledgeable in 3D electromagnetic (EM) simulation of high-frequency circuits. To give electrical engineering students a better understanding of the behavior of electromagnetic fields, experiments including the use of 3D EM simulation software were proposed. Most students get lost in differential equations, curls, and divergences; this thesis aims to remedy that by exposing them to 3D EM simulation, which may motivate them toward further study in electromagnetics. Also, experience using EMPro is very beneficial for future RF/microwave/antenna engineers, as use of 3D EM simulation is becoming a requirement for this field. 3D EM simulators solve problems where using classical analysis techniques is impractical. Classical EM solutions to simple objects such as boxes, cylinders, and spheres, are widely known; but when the object is more complex, numerical approaches are preferred for their speed.
Currently, Cal Poly does not use 3D electromagnetic simulation in any of its courses. Targeted relevant courses include EE 335/375: EM Fields & Transmission Lines, EE 402: EM Waves, EE 405/445: High-Frequency Amplifier Design, EE 425/455: Analog Filter Design, EE 502: Microwave Engineering, and EE 533: Antennas. As a starting point, EE 425/455 was targeted.
In choosing which filters to investigate, simplicity and cost were the most important factors. For simplicity, transverse electromagnetic (TEM) mode filters were chosen; also, using a trough design for these filters would allow for simple construction and access. Also, a circular waveguide filter was chosen as an alternative to the TEM filters, as the modes are either transverse electric or transverse magnetic. To lower costs, printed circuit board was used to construct the filters, along with brass tubing, semi-rigid coaxial cable, and copper plumbing caps.
From these guidelines, three electronic bandpass filter experiments were investigated: a 1 GHz half-wave coaxial resonator filter, a 2 GHz copper end cap filter, and a tunable 1 GHz quarter-wave coaxial resonator filter. Electric and magnetic field coupling was used to excite the filters. They were then simulated using finite difference time domain (FDTD) simulations in Agilent EMPro. From the simulations, tradeoffs between insertion loss and bandwidth were observed. After, the filters were built and measured using a network analyzer. The quarter-wave filter was incorporated in Cal Poly’s EE 455 course during spring 2012. Students completed an EMPro tutorial, simulated the filters, and measured them using network analyzers. Student feedback was mixed, and modifications were made for future implementations.
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Muller, Jan. "Electrical engineering professionals’ continuing professional development needs within one South African company." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/96694.
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Thesis (MPhil)--Stellenbosch University, 2015.ENGLISH ABSTRACT: The aim of the study performed in 2014 was to identify what the Continuing Professional Development (CPD) needs are of a selected group of electrical engineering professionals from one company in South Africa. The interpretivist research paradigm formed the basis for the “Interactive Qualitative Analysis” methodology used in the study. Due to limitations research was focused on only one constituency, a selected group of electrical engineering professionals in one organisation, which is close to, but have very little power over the specific phenomenon of CPD. Research activities included conducting focus group and individual interviews with participants to gain a better understanding of identified problem through the analysis and interpretation of the collected data. The phenomenon of CPD was found to lie within the spectrum of lifelong learning. Due to increasingly fast changing technological and work environments, practicing professionals take part in professional development, if it is compulsory or not, in order to stay competitive in the global arena. Research has shown that compulsory CPD for registered engineering professionals may further their professional development. From the “Possible Implications for CPD Provision for Engineering Professionals” document several issues and concerns were identified, which influence engineering professionals’ perception of the professional body. The CPD system and CPD provision facilitated by the Engineering Council of South Africa (ECSA) may be one of the key reasons why many practicing engineers choose not to register professionally. Through this study the perceived and proposed CPD needs for the selected group of electrical engineering professionals have been identified, but to identify the actual needs of practicing engineering professionals in South Africa, a more detailed study will need to be done that should include all the constituencies that practice within the engineering environment or have any influence on the CPD phenomenon. The study also identified aspects that could help to improve the CPD system and the available CPD initiatives, and enhance the leadership from the professional body. This may positively influence the perception of practicing engineering professionals. Such positive perceptions could result in more practicing engineering professionals registering with ECSA and maintaining their professional registration.
AFRIKAANSE OPSOMMING: Die doel van die studie uitgevoer in 2014 was om die Voortgesette Professionele Ontwikkeling (VPO) behoeftes van ‘n geselekteerde groep elektriese ingenieurs van een maatskappy in Suid-Afrika te bepaal. Die interpretatiewe navorsingsparadigma het die “Interaktiewe Kwalitatiewe Analise” metodologie wat gebruik is in die studie onderlê. Binne die studie beperkinge is gefokus op slegs een konstituensie, ‘n geselekteerde groep professionele elektriese ingenieurs binne een organisasie, wie digby die spesifieke fenomeen van VPO funksioneer, maar baie beperkte mag daaroor het. Navorsingsaktiwiteite het fokusgroeponderhoude en individuele onderhoude met deelnemers ingesluit om ‘n beter begrip van die geïdentifiseerde probleem te verkry deur analise en interpretasie van die ingesamelde data. Die fenomeen van VPO lê binne die spektrum van lewenslange leer. As gevolg van ‘n toenemend snel veranderende tegnologiese en werksomgewing, neem professionele praktisyns deel aan professionele ontwikkeling, of dit verpligtend is of nie, en bly sodoende kompeterend in die globale arena. Maar navorsing het ook bewys dat verpligte VPO vir geregistreerde ingenieurspraktisyns hul professionele ontwikkeling tot voordeel kan strek. Vanuit die “Possible Implications for CPD Provision for Engineering Professionals” dokument is verskeie kwessies en knelpunte geïdentifiseer wat professionele ingenieurs se persepsies van die professionele liggaam mag beïnvloed. Die VPO sisteem en VPO verskaffing wat deur die Suid-Afrikaanse Raad vir Ingenieurswese (SARI) gefasiliteer word, mag een van die kernredes wees waarom vele ingenieurspraktisyns kies om nie professioneel te registreer nie. Die perseptuele en voorgestelde VPO behoeftes van ‘n geselekteerde groep professionele elektriese ingenieurspraktisyns is geïdentifiseer in hierdie studie, maar om die werklike behoeftes van professionele ingenieurspraktisyns in die breër Suid-Afrikaanse konteks te bepaal is ‘n meer gedetailleerde studie nodig wat al die konstituensies insluit wat praktiseer binne die ingenieursomgewing of die VPO fenomeen in dié konteks beïnvloed. Die studie het ook aspekte identifiseer wat kan help om die huidige VPO sisteem en insiatiewe te verbeter, en die leierskap van die professionele liggaam tot voordeel kan strek. Dit mag ‘n positiewe invloed hê op die persepsies van professionele ingenieurspraktisyns. Diesulke positiewe persepsies kan lei tot meer professionele ingenieurspraktisyns wat registreer by SARI en hul professionele registrasie byhou.
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Tang, Chee Meng. "Control Channel Vulnerability Analysis of the Institute of Electrical and Electronics Engineers 802.16m-2011 and 802.16- 2009 Standards." Thesis, Monterey, California. Naval Postgraduate School, 2012. http://hdl.handle.net/10945/17466.
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Approved for public release; distribution is unlimitedThe Institute of Electrical and Electronics Engineers (IEEE) 802.16 set of standards, known as Worldwide Interoperability for Microwave Access (WiMAX), is a family of standards widely deployed for wireless network access. Though WiMAX security vulnerabilities have been extensively analyzed, the IEEE 802.16m-2011 standard incorporates the new advanced air interface (AAI), which is substantially different from legacy standards and justifies reexamination on a clean slate. In this research, the vulnerabilities of IEEE 802.16m-2011 control channels are examined at the medium-access (MAC) and the physical (PHY) layers with proposed attack vectors. Methodologies are proposed to overcome challenges in terms of the timing and power associated with manipulating control channels. Attacks that manipulate the transmission power of mobile stations are examined in detail, while other attacks on IEEE 802.16m-2011, including multiple-input multiple-output (MIMO) disruption, network-entry disruption, and water-torture are also discussed. Out of fifteen vulnerabilities presented, thirteen were not previously identified for IEEE 802.16m-2011. Existing and new proposed vulnerabilities within legacy standards (specifically IEEE 802.16-2009) are also discussed, including transmission power manipulation, entry procedure attacks, water-torture attacks, and automatic repeat request attacks. Twelve of eighteen vulnerabilities presented were not previously discussed.
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Perjanik, Nicholas Steven. "Tacit Knowledge Capture and the Brain-Drain at Electrical Utilities." Thesis, Walden University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10118978.
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As a consequence of an aging workforce, electric utilities are at risk of losing their most experienced and knowledgeable electrical engineers. In this research, the problem was a lack of understanding of what electric utilities were doing to capture the tacit knowledge or know-how of these engineers. The purpose of this qualitative research study was to explore the tacit knowledge capture strategies currently used in the industry by conducting a case study of 7 U.S. electrical utilities that have demonstrated an industry commitment to improving operational standards. The research question addressed the implemented strategies to capture the tacit knowledge of retiring electrical engineers and technical personnel. The research methodology involved a qualitative embedded case study. The theories used in this study included knowledge creation theory, resource-based theory, and organizational learning theory. Data were collected through one time interviews of a senior electrical engineer or technician within each utility and a workforce planning or training professional within 2 of the 7 utilities. The analysis included the use of triangulation and content analysis strategies. Ten tacit knowledge capture strategies were identified: (a) formal and informal on-boarding mentorship and apprenticeship programs, (b) formal and informal off-boarding mentorship programs, (c) formal and informal training programs, (d) using lessons learned during training sessions, (e) communities of practice, (f) technology enabled tools, (g) storytelling, (h) exit interviews, (i) rehiring of retirees as consultants, and (j) knowledge risk assessments. This research contributes to social change by offering strategies to capture the know-how needed to ensure operational continuity in the delivery of safe, reliable, and sustainable power.
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Bruton, Elizabeth Mary. "Beyond Marconi : the roles of the Admiralty, the Post Office, and the Institution of Electrical Engineers in the invention and development of wireless communication up to 1908." Thesis, University of Leeds, 2012. http://etheses.whiterose.ac.uk/4431/.
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One of the first histories of wireless communications, J.J. Fahie's A History of Wireless Telegraphy 1838-1899 (1899), was written by a contemporary to many of the early practitioners within its pages and featured an illustrated list entitled “The Arch Builders of Wireless Telegraphy”. This list stretched from key contributors to the early study of electromagnetism such as Ampère, Faraday, and Maxwell through to developers of early wireless apparatus and systems such as Branly, Lodge, Preece, and Marconi. The equal recognition recorded to these twelve men and the collective contribution of scientists, engineers, government employees, along with men of commerce, to the embryonic field of wireless communications has been mostly ignored in the existing body of scholarship on wireless telecommunications. In this thesis, I offer an early history of wireless communications deeply familiar to contemporaries but take a novel approach and study the roles of institutions rather than individuals. Traditionally institutions are presented as grateful consumers and passive users of telecommunication systems. I utilise contemporary periodicals and rich yet underused archival resources in order to map the influence, agency, and roles of three historic case studies – the Admiralty, the Post Office, and the Institution of Electrical Engineers (IEE) – in wireless communications. Furthermore I will consider how these institutions constrained the activities of the Marconi Company. This thesis begins with a consideration of the community, expertise, and practices of wireless practitioners centred about the Post Office and IEE that pre-dated the discovery of Hertzian waves and Marconi's arrival in Britain in 1896. Furthermore I will explore the technical expertise located within the Royal Navy and show how this shaped military demand for wireless communication in the early twentieth century. The final two chapters of this thesis explore the influence and agency of the Admiralty and the Post Office in domestic legislation and international regulations of wireless communications. This thesis demonstrates how and why these “institutional innovations” and activities shaped this technology during its formative years and laid the foundation stone for wireless communications and its successes in Britain and beyond.
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De, Bellis John J. "Optimization procedure for electric propulsion engines." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1999. http://handle.dtic.mil/100.2/ADA374329.
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Thesis (M.S. in Applied Physics) Naval Postgraduate School, December 1999."December 1999". Thesis advisor(s):Oscar Biblarz, James Luscombe. Includes bibliographical references (p. 71-73). Also available online.
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Mulligan, Jennifer Joyce 1978. "Detection and recovery from the obvious engineer attack." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/87344.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.Includes bibliographical references (leaves 65-66).
by Jennifer Joyce Mulligan.
S.M.
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Shah, Hemang J. Fontecchio Adam. "Engineered interfaces for liquid crystal technology /." Philadelphia, Pa. : Drexel University, 2007. http://hdl.handle.net/1860/1788.
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Arapostathis, Efstathios. "Consulting engineers in the British electric light and power industry, c. 1880-1914." Thesis, University of Oxford, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433399.
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Cheng, Hoi Wai Thomas 1977. "Identifying customers' unmet needs using a virtual advisor and engineer." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/86651.
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Thesis (M.Eng. and S.B.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2001.Includes bibliographical references (leaf 73).
by Hoi Wai Thomas Cheng.
M.Eng.and S.B.
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Strauss, Johannes Matthias. "Direct piston displacement control of free-piston Stirling engines." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/85604.
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Thesis (PhD)-- Stellenbosch University, 2013.ENGLISH ABSTRACT: Control of beta-type free-piston Stirling engines has been the topic of research and development for many years. In this dissertation, an alternative approach to free-piston Stirling engine control, namely direct piston displacement control, is proposed. Direct piston displacement control entails the instantaneous and direct control of the piston displacement to control the engine according to preferred criteria, e.g. maximum power conversion or efficiency. To control free-piston engines in this manner, it is necessary to independently control both the displacement of the displacer and the power piston in real time. The primary arrangement by which to achieve this is through external control of the instantaneous forces exerted by the linear electrical machines fixed to the pistons. The challenge of displacement control is whether suitable linear machine technology exists or whether technology could be established that would adhere to the requirements of real time direct control. To answer the question whether direct piston displacement control is at all possible, a process was followed to set specifications that linear machines should adhere to and to set design guidelines for linear machines and free-piston Stirling engines. The first step was to establish the ability to simulate free-piston Stirling engine dynamics accurately. This was done by adapting a second order formulation and to verify and improve the accuracy thereof by comparing simulated results with experimental results of one of the best documented Stirling engines, namely the GPU-3 engine. It was found that this second order formulation could simulate the GPU-3 engine to a fair degree of accuracy. Key indicators were defined and later refined with the view of setting specifications. A case study of the influence of a range of variations, including operational, dimensional and other variations, on the dynamics of the GPU-3 was then undertaken. From the findings of this case study, specifications of the key indicators and design guidelines were established. A design optimisation approach was proposed to evaluate linear machine topologies. This approach makes specific provision for the specifications that linear machines need to adhere to, as well as for representative dynamic responses of the forces exerted on the linear machine by the displacer or the power piston. These representative responses and the associated piston displacement were determined for the displacer, the power piston and the combination of the two from the study conducted to set specifications. An air-core, longitudinal flux linear machine with surface mounted permanent magnets (LFPM) was then evaluated to determine its suitability for direct piston displacement control. This linear machine topology was optimised for the traditional approach to establish a benchmark with which to compare subsequent optimisations. The LFPM linear machine not only compared well with other topologies for the traditional application in resonant free-piston Stirling engines, but it was found also to be able to perform displacement control for both the displacer and the power piston. For both pistons, displacement should however be limited to sinusoidal displacement, and in the case of the displacer, an important qualification is that the linear machine should be assisted by spring forces to reach practical design optimisations. Direct piston displacement control is shown to be possible. Future work should concentrate on the practical implementation thereof in free-piston Stirling engines.
AFRIKAANSE OPSOMMING: Die beheer van beta-tipe vrysuier Stirling enjins is al vir baie jare die onderwerp van navorsing en ontwikkeling. In hierdie proefskrif word ’n alternatiewe benadering tot vrysuier Stirlingenjins voorgestel, naamlik direkte suierverplasingsbeheer. Direkte suierverplasingsbeheer behels die oombliklike en direkte beheer van die suierverplasing om die enjin volgens voorkeur kriteria, soos maksimum drywingsomsetting of benuttingsgraad, te beheer. Om vrysuier enjins op hierdie wyse te beheer, is dit noodsaaklik om intyds die verplasing van beide die verplaser en die werksuier onafhanklik te beheer. Die primêre wyse om dit te bereik is deur eksterne beheer van die oomblikskragte wat uitgevoer word deur die lineêre masjiene wat vas is aan die suiers. Die uitdaging van verplasingsbeheer is of toepaslike lineêre masjien tegnologie bestaan en of tegnologie gevestig kan word wat sal voldoen aan die vereistes van intydse direkte beheer. Om die vraag te beantwoord of direkte suierverplasingsbeheer hoegenaamd moontlik is, is ’n proses gevolg om spesifikasies daar te stel waaraan lineêre masjiene moet voldoen en om ontwerpsriglyne vir lineêre masjiene en vrysuier Stirling enjins te stel. Die eerste stap was om die vermoë daar te stel om vrysuier Stirling enjin dinamika akkuraat te simuleer. Dit is gedoen deur ’n tweede orde formulering aan te pas en om die akkuraatheid daarvan te kontroleer en te verbeter deur gesimuleerde resultate met eksperimentele resultate van een van die bes gedokumenteerde Stirling enjins, naamlik die GPU-3 enjin, te vergelyk. Daar is bevind dat die tweede orde formulering die GPU-3 tot ’n redelike mate akkuraat kon simuleer. Sleutel aanwysers is gedefinieer en later verfyn met die oog op die daarstelling van spesifikasies. ’n Gevallestudie van die invloed van ’n reeks variasies, insluitende operasionele, dimensionele en ander variasies, op die dinamika van die GPU-3 is onderneem. Gegrond op die bevindinge van hierdie gevallestudie kon spesifikasies en ontwerpsriglyne vasgestel word. ’n Ontwerpsoptimeringsbenadering is voorgestel om lineêre masjiene te evalueer. Hierdie benadering maak spesifiek voorsiening vir die spesifikasies waaraan lineêre masjiene moet voldoen, sowel as verteenwoordigende dinamiese response van die kragte wat op die lineêre masjien van die verplaser en die werksuier uitgeoefen word. Vanaf die bevindinge van die studie wat uitgevoer is om spesifikasies daar te stel, is verteenwoordigende response en gepaardgaande suierverplasing bepaal vir die verplaser, die werksuier en die kombinasie van die twee. ’n Lugkern, longitudinale vloed lineêre masjien met oppervlak-gemonteerde permanente magnete (LVPM) is toe geëvalueer om die geskiktheid daarvan te bepaal vir direkte suierverplasingsbeheer. Hierdie lineêre masjien topologie is geoptimeer vir die tradisionele benadering om ’n maatstaf te vestig waarteen daaropvolgende optimerings vergelyk kan word. Die LVPM lineêre masjien vergelyk nie net goed met ander topologieë vir die tradisionele toepassing in resonante vrysuier Stirling enjins nie, maar daar is ook bevind dat dit in staat is om verplasingsbeheer te doen vir beide die verplaser en die werksuier. Vir beide suiers moet die verplasing egter tot sinusvormige verplasing beperk word en in die geval van die verplaser, is ’n belangrike kwalifikasie dat die lineêre masjien ondersteun moet word deur veerkragte om praktiese ontwerpsoptimerings te bereik. Daar is aangetoon dat direkte suierverplasingsbeheer moontlik is. Toekomstige werk moet konsentreer op die praktiese implementering daarvan in vrysuier Stirling enjins.
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Weiss, Ron 1970. "Cellular computation and communications using engineered genetic regulatory networks." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8228.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2001.Includes bibliographical references (p. 130-138).
In this thesis, I present an engineering discipline for obtaining complex, predictable, and reliable cell behaviors by embedding biochemical logic circuits and programmed intercellular communications into cells. To accomplish this goal, I provide a well-characterized component library, a biocircuit design methodology, and software design tools. I have built and characterized an initial cellular gate library with biochemical gates that implement the NOT, IMPLIES, and AND logic functions in E. coli cells. The logic gates perform computation using DNA-binding proteins, small molecules that interact with these proteins, and segments of DNA that regulate the expression of the proteins. I introduce genetic process engineering, a methodology for modifying the DNA encoding of existing genetic elements to achieve the desired input/output behavior for constructing reliable circuits of significant complexity. I demonstrate the feasibility of digital computation in cells by building several operational in-vivo digital logic circuits, each composed of three gates that have been optimized by genetic process engineering.
(cont.) I also demonstrate engineered intercellular communications with programmed enzymatic activity and chemical diffusions to carry messages, using DNA from the Vibrio fischeri lux operon. The programmed communications is essential for obtaining coordinated behavior from cell aggregates. In addition to the above experimental contributions, I have developed BioSPICE, a prototype software tool for biocircuit design. It supports both static and dynamic simulations and analysis of single cell environments and small cell aggregates. Finally, I present the Microbial Colony Language (MCL), a model for programming cell aggregates. The language is expressive enough for interesting applications, yet relies on simple primitives that can be mapped to the engineered biological processes described above.
by Ron Weiss.
Ph.D.
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Morris, Richard James Horatio. "Optimisation studies on strain-engineered Germanium heterostructures." Thesis, University of Warwick, 2003. http://wrap.warwick.ac.uk/52780/.
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The physical gate lengths of state-of-the-art CMOS devices are 45 nm and are anticipated to reach just 20 nm by 2007. Due to the prohibitive capital expenditure required for next-generation CMOS technologies, leading device manufacturers are now exploring exotic device architectures and novel substrates in which significant device performance enhancements may by obtained using the existing device fabrication infrastructure. This thesis reports studies made on an initial evaluation of hole transport properties in strained Ge channels and comprises physical and electrical characterisation of these heterostructures as well as the analysis of SiGe layers using secondary ion mass spectrometry. The initial work of thesis describes the growth, characterisation and optimisation of a novel strained Ge substrate. The substrate technology was developed using a hybrid-epitaxy technique in which a SiGe strain-relaxed buffer layer, so called "virtual substrate", was grown using a ultra-high vacuum chemical-vapour deposition growth technique and the active strained Ge layer was grown using a solid-source molecular-beam epitaxy growth technology. An advanced chemical cleaning procedure has been developed which includes a modified Piranha etch. The novel cleaning procedure enables the successful integration of the two growth techniques. Significant hole carrier transport enhancements were observed for holes contained within the strained Ge channel. Optimisation of the hole mobility was achieved by the reduction of carrier scattering such as interface roughness scattering and point defect scattering. The optimisation methods employed included growth temperature iterations to reduce Ge channel roughening via elastic relaxation and, channel thickness iterations were also employed in order to minimize channel roughening and defect nucleation. Post-growth annealing procedures were used to combat defects arising from low temperature growth. The Ge heterostructures were grown on strain relaxed buffer layers, terminating with a Ge content of 60%. The optimised strained Ge channel thickness was found to be 20 nm and the growth temperature of the active layers was reduced to 350°C so as to minimise surface roughening. As grown point defects were eliminated at an optimised post-growth anneal temperature of 650°C for 30 minutes under dry N2• Hall mobilities reached 1910 cm2Ns at room temperature rising to 26,900 cm2Ns at 10K. A magneto-conductivity transfonnation measurement and maximum entropy mobility spectrum analysis revealed a room temperature drift mobility of 2700 cm2Ns at a carrier density of l.Ox1012 cm-2 . This result represents a 15-fo1d increase in hole mobility compared to conventional Si substrates at comparable effective fields. The second and important part of this thesis addresses charging effects observed when profiling undoped SiGe layers and the quantification of Ge fraction within SiGe layers using secondary ion mass spectrometry. Due to the highly resistive spreading resistance found for undoped SiGe layers when profiled using an O2+ incident beam, charging effects were found to mask the true layer profile. In order to overcome this problem a new approach is discussed for the first time. By illuminating the sample with a red laser light (wavelength 635mn) electron-hole pairs were created via photon absorption. The excess charge carriers were sufficient to overcome localised charging effects induced by the primary ion beam during SIMS analysis. In this manner, total charge suppression was achieved, thereby enabling a true determination of the SiGe sample profile to be obtained via SIMS. Finally, an analytical method enabling the accurate determination of Ge content of SiGe layers is discussed. The method employs a comparative ion yield methodology and enables both the spatial distribution and Ge concentration of SiGe layers to be accurately determined from a single SIMS measurement.
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GAMA, SINVAL ZAIDAN. "NEW PROFILE FOR AN ELECTRIC ENGINEER IN THE BEGINING OF THE 21ST CENTURY." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2002. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=3852@1.
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ELETROBRAS - CENTRAIS ELÉTRICAS BRASILEIRAS S. A.Este trabalho contempla o estudo das propostas REENGE para o perfil de formação do engenheiro, analisando sua fundamentação diante das mudanças estruturais do setor elétrico brasileiro; e pesquisa as necessidades de formação do engenheiro eletricista na visão do mercado de trabalho do mesmo setor, através de pesquisa de campo. Baseado no confronto das opiniões assim levantadas, o trabalho estabelece um perfil de formação do engenheiro eletricista, informado pela visão de futuro da academia e pelas necessidades dos integrantes do mercado de trabalho, fornecendo subsídios para que as diversas instituições de ensino superior estabeleçam seus perfis de formação particulares, conforme estabelecem as Diretrizes Curriculares Nacionais do Curso de Engenharia. O perfil de formação indicado não se restringe a uma lista de conteúdos, e sim a uma abordagem diferente de transmissão de Saberes, onde um conjunto de conhecimentos, habilidades e atitudes necessários para as competências desejáveis é indicados.
This work covers the studies of the REENGE proposals for knowledge background of an engineer background, analyzing its statements on the electric sector structural changes; and it focus the background needs for an electric engineer using the market view of the same sector, throughout field research. Based on the opinions check that came up, the work establishes a background profile for the electric engineer, formed by the academy future vision and the needs of the integrants of the labor market, giving support for many higher education institutions to establish its particular profile background, as the national Curriculum directions for the electric engineer course are established. The background profile indicated is not limited to a list of content, it is a different knowledge transference approach, in which knowledge, skills and attitudes for the necessary desired competence are indicated.
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Roy, Tapashree. "Control and localisation of light with engineered nano-structures." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/369991/.
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In this thesis I present my research on nano-scale light control using several novel approaches. I have demonstrated a planar metal nano-structure with cylindrical symmetry that is designed to create a super-oscillation of electromagnetic waves to focus light down to sizes smaller than the Abbe diffraction limit. For the first time this super-oscillatory lens was experimentally used for imaging of nano-structures. A pair of 0:3λ diameter nano-holes with 0:16λ edge-to-edge separation were resolved. I have demonstrated a novel type of super-oscillatory lens which produces a continuous distribution of sub-wavelength light localisations extending over several wavelengths along the optical axis. This `optical needle' is also characterised by a large field of view. I have experimentally demonstrated a optical-needle-lens with 7µm depth of focus and 16% narrower than a diffraction-limited focal spot. I have characterised the point spread function of the above-mentioned super-oscillatory lenses, i.e., their ability to accurately image a point source. The images of the point source generated by these super-oscillatory lenses are at least 24% smaller than that produced by an ideal glass lens restrained by the Abbe diffraction limit. I have experimentally verified the imaging characteristics of the optical-needle-lens and demonstrated its ability to detect the off-axis placement of a point-like source. I have developed the nano-fabrication processes for manufacturing the super-oscillatory lenses on thin films of metals (Au, Al, Ti) using gallium focused-ion-beam milling technology. The focusing characteristics of the fabricated structures showed very good agreement with computational predictions. I have computationally shown that objects placed within the field of viewfocfocus of the optical-needle-lens can be imaged with super-resolution quality. This is a significant improvement over the sub-wavelength-step scanning imaging technique reported in this thesis for the other kind of super-oscillatory lens. For example, a super-oscillatory lens can resolve a `random' cluster of 0:15λ diameter nano-holes with the smallest edge-to-edge separation of 0.28λ. I have experimentally demonstrated the first prototype of a solid-immersion superoscillatory lens that promises to achieve a 50 nm hotspot with 405 nm illumination for applications in heat-assisted magnetic recording technology. I have demonstrated for the first time a planar diffraction grating for visible light designed by arranging meta-molecules to produce a periodic phase ramp. I have also demonstrated the first ever metamaterial-based planar lens-array that produced a 2D array of sub-wavelength foci. Finally, I have provided the first experimental evidence that photoluminescence of gold can be substantially enhanced by patterning the film with designed 2D nano-structured array (or, metamaterials). When resonant two-photon excitation is used the metamaterial enhances the photoluminescence by more than 76 times. I have also observed that the photoluminescence emission peaks are linked to the frequencies of absorption resonances in the metamaterials.
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Gohary, Mohamed Morsy Abdel Meguid Salama el. "Diesel engines and solar energy for electric and cooling applications." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=973168242.
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Willerström, Jakob, Adam Linde, and Johannes Fagrell. "Electrifying the construction process : Replacing diesel engines with electric motors." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-254206.
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Diesel engines are commonly used in construction machines, for example excavators. In a diesel engine, the combustion of diesel is a process with a considerable environmental impact, with high amounts of emitted greenhouse gases. The bachelor thesis creates a model that investigates the potential of decreasing the environmental impact when replacing diesel engines with electric motors in the construction phase of the construction process of buildings. The model was made in three steps. In the first step the electric motors’ energy consumption were compared with the diesel engines’ energy consumption. Secondly, the results of the comparison were contrasted against the results of an implemented example as to determine the relevancy of the model. Finally, the carbon dioxide equivalent values of the diesel engines and the electric motors were calculated and compared. The result shows that there is a big potential of decreasing the environmental impact. The reduction is in the order of 63%-99% and it is shown that the share of renewable energy sources in the electricity mix is vital as to make the potential as large as possible.
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Ng, Man Cheuk 1980. "Rapid designs for cache coherence protocol engines in Bluespec." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/30166.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Includes bibliographical references (p. 91-92).
In this thesis, we present the framework for Rapid Protocol Engine Development (RaPED). We implemented the framework in Bluespec, which is a high level hardware language based on Term Rewriting Systems (TRSs). The framework is highly parameterized and general, thus allowing designers to design any protocol engine in a short period. Since protocol engines can be developed rapidly, designers can compare different designs instead of freezing the design prematurely in the development process. We used the RaPED to implement a cache coherence protocol for Shen and Arvind's Commit-Reconcile and Fences (CRF) memory model [1]. The CRF allows scalable implementations of shared memory systems by decomposing memory access operations into simpler instructions. However, the focus for Shen's Cachet protocol for the CRF was adaptivity and correctness, it ignored some important implementation issues such as cache-line replacement, efficient buffer management and compatibility with multiword cache lines. In this thesis, we present a protocol called the Multiword Base protocol, which avoids these limitations. We defined the Multi-word CRF (MCRF) memory model to help us to prove the correctness of Multiword Base. The MCRF is a specialization of the CRF with modifications that summarizes the properties of multiword cache lines. We show that Multiword Base is a correct implementation of the CRF by using the MCRF to simulate Multiword Base. Apart from using multiword cache lines, many cache coherence protocols allow a cache to get data directly from another cache. The caches having this property is calling the snoopy caches. In this thesis, we present a CRF variant called the Snoopy CRF (SCRF) memory model, which gives hints to incorporate snoopy caches to the implementations of the CRF.
by Man Cheuk Ng.
S.M.
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Dasgupta, Sukrit De Oliveira Jaudelice Cavalcante. "Improving resource management in multi-protocol label switched traffic engineered networks /." Philadelphia, Pa. : Drexel University, 2008. http://hdl.handle.net/1860/2821.
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Lee, Hsu-Yi. "Ultrastructure and nanomechanical properties of aggrecan from native cartilage and engineered tissue." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/60099.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student submitted PDF version of thesis.
Includes bibliographical references (p. 147-159).
Electrostatic interactions associated with aggrecan, one of the major components of the cartilage extracellular matrix, are responsible for ~50% of the equilibrium compressive elastic modulus of the tissue. The bottle-brush-shaped aggrecan consists of a core protein to which ~100 sulfated glycosaminoglycan (sGAG) chains are attached. Loss of sGAG is one early events in the pathogenesis of osteoarthritis and the resulting degradation of cartilage is irreversible due to its limited capacity for self-repair. Tissue engineering is one of the techniques which holds great potential for cartilage repair. In order to achieve successful repair, a clear understanding of native and engineered cartilage aggrecan is essential. With atomic force microscopy and high resolution force microscopy, the structure of aggrecan single molecules and the nanomechanical properties of an end-grafted aggrecan monolayer were quantified. Adult human aggrecan showed significantly shorter GAG chains and core proteins as well as lower molecular stiffness compared to that of newborn aggrecan. After enzymatic digestion of chondroitin sulfate (CS) GAGs, keratan sulfate GAG chains were visualized near the N-terminal domain of a less extended core protein. Direct visualization of aggrecan aggregates confirmed the structure of the constituent hyaluronic acid, aggrecan G1 domain, and link protein. Increased flexibility of the core protein was found near the G1 domain, which may facilitate the aggregate self-assembly process. Aggregated and non-aggregated aggrecan both showed remarked flexibility (i.e., decreased extension ratio) when the aggrecan areal density increased. These findings on intra- and inter-molecular structure provide insights into the structure-property relationships of aggrecan in vivo. Aggrecan produced by animal-matched bone marrow stromal cells (BMSCs) and chondrocytes seeded in peptide hydrogel were evaluated for their age-associated structure and nanomechanical properties. Independent of age, BMSCs produced longer core proteins and GAG chains than the chondrocytes, suggesting that the BMSC-produced aggrecan was characteristic of that from young cartilage. Comparison of the adult BMSC-produced aggrecan with adult cartilage-extracted aggrecan revealed that adult BMSC-aggrecan has a phenotype characteristic of young growth cartilage: primarily full-length aggrecan core, longer GAG chains and a higher content of chondroitin-4-sulfate in the CS-GAG chains, the latter identified via fluorescence assisted carbohydrate electrophoresis. The nanomechanical stiffness of BMSC-aggrecan was demonstrably greater than that of cartilage-aggrecan at the same total sGAG (fixed charge) density. These results support the use of adult BMSCs for cell-based cartilage repair.
by Hsu-Yi Lee.
Ph.D.
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Varma, Sarvesh. "Cell-based sensors for quantifying cell health and disease progression in engineered systems." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/112031.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 180-200).
Healthy cells create healthy beings, while dysfunctional cells cause disease. Studying disease requires an understanding of how cells become dysfunctional from physiological states. Gaining this insight in vitro involves subjecting cells to relevant microenvironments and utilizing methodologies for assaying cells. Critically, to obtain accurate and unbiased insight, it is important to ensure that the cellular microenvironment remains representative, and that the assay methodology itself does not adversely perturb cell state. This thesis presents an approach where cells 'report' upon their healthy or stressed states, which could be assessed to either learn disease mechanisms, or quantified to design 'cell-friendly' methodologies. We engineered cell-based sensors that emit stress-regulated fluorescence, and applied them to characterize how distinct microenvironments regulate cell health. Here, we describe two endeavors that highlight the utility of this approach. We first developed cell stress sensors for a diverse bioinstrumentation community to quantify the impact of engineered systems and methodologies upon cell health. Using NIH3T3 cells, we engineered sensors that report on stresses induced by DNA damage, heat shock, or fluid shear stresses. Each sensor provides sensitive and specific responses to stress-induced pathways (relevant to several cell types), and can be used for a multiplexed stress-readout. The sensors do not require additional reagents and can be conveniently quantified with flow cytometry and real-time imaging. Successful distribution and adoption of the sensors by external users enabled quantitative characterization of flow sorting systems in the context of cell health, which was not explored before. Hence, the cell-sensor methodology designed as an 'open source' tool, could potentially serve as a novel standard for quantifying cell stress, and broadly for designing 'cell-friendly' methodologies. We further utilized cell-based sensors to gain biological insight into stress-regulated diseases. We focused on atherosclerosis, a flow-regulated cardiovascular disease that remains a major cause of morbidity and mortality worldwide. We engineered a novel microfluidic platform to study atherogenesis in vitro that overcomes several limitations of existing models. This device emulates in vivo microenvironments by applying programmable spatiotemporal flow profiles observed from human patients directly upon cultured human cells. Utilizing an endothelial cell-based sensor (that reports on vascular health), device flows were validated with known biomarkers and endothelial signatures. Subsequently, these sensors were used to gain novel insight upon atherogenesis through the impact of hemodynamic flows upon endothelial function. Overall, this thesis presents a facile and quantitative approach to investigate complex cell-stress emergent from diverse bioinstrumentation or within a disease microenvironment, which can be utilized to discover how environmental conditions regulate cell physiology, and human health.
by Sarvesh Varma.
Ph. D.
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Recht, Daniel. "Energetic Beam Processing of Silicon to Engineer Optoelectronically Active Defects." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10305.
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This thesis explores ways to use ion implantation and nanosecond pulsed laser melting, both energetic beam techniques, to engineer defects in silicon. These defects are chosen to facilitate the use of silicon in optoelectronic applications for which its indirect bandgap is not ideal. Chapter 2 develops a kinetic model for the use of point defects as luminescence centers for light-emitting diodes and demonstrates an experimental procedure capable of high-throughput screening of the electroluminescent properties of such defects. Chapter 3 discusses the dramatic change in optical absorption observed in silicon highly supersaturated (i.e., hyperdoped) with the chalcogens sulfur, selenium, and tellurium and reports the first measurements of the optical absorption of such materials for photon energies greater than the bandgap of silicon. Chapter 3 examines the use of silicon hyperdoped with chalcogens in light detectors and concludes that while these devices display strong internal gain that is coupled to a particular type of surface defect, hyperdoping with chalcogens does not lead directly to measurable sub-bandgap photoconductivity. Chapter 4 considers the potential for Silicon to serve as the active material in an intermediate-band solar cell and reports experimental progress on two proposed approaches for hyperdoping silicon for this application. The main results of this chapter are the use of native-oxide etching to control the surface evaporation rate of sulfur from silicon and the first synthesis of monocrystalline silicon hyperdoped with gold.Engineering and Applied Sciences
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Ramunno, Michael Angelo. "Control Optimization of Turboshaft Engines for a Turbo-electric Distributed Propulsion Aircraft." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1587657623577243.
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Morandin, Mattia. "Electric Drives with Permanent Magnet Synchronous Machines Connected to Internal Combustion Engines." Doctoral thesis, Università degli studi di Padova, 2013. http://hdl.handle.net/11577/3423439.
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In recent years, the increasing cost of oil and Earth global warming due to greenhouse gases have pushed the scientific research, the governments and thus the markets in the direction of a higher efficiency of the systems in order to reduce the use of this fuel and therefore its associated emissions of CO2.
Nowadays, the most involved sectors of this technological revolution are the fields of electricity generation and the transportation. In fact, these two sectors are the main accountable of CO2 global emission, that are associated for about 45% to electricity generation and for about 30% to transport. Moreover, it should be noted that although the oil is not a renewable energy source, currently about 40% of the production world energy depends on oil and the level of dependence rises to about 80% in the transportation sector where the majority of vehicles is powered by an engine fueled by oil derivatives.
For these reasons, the scientific research in the last decade was focusing on these issues in particular in emerging fields such as distributed cogeneration and hybrid electric vehicles. In particular, new systems of distributed energy are studied, which are capable to increase the energy efficiency of the plant because the electrical and thermal energy are produced in combined way and directly in the site where they are required. In this way the losses of the network can be reduced. Instead, in the field of hybrid electric vehicles the use of the electric machine can help to increase the efficiency of the power-train in the various working points. These hybrid systems allow to reduce up to 30% the fuel consumption and associated emissions compared to a conventional vehicle.
With this historical context this thesis is focused in the study of a power-train structure of domestic cogeneration system or a vehicle, namely the analysis of a system composed by an internal combustion engine directly connected to an electric machine. The two principal tasks of the electric machine are: startup of the internal combustion engine and generate on electric energy. In the case of a hybrid electric vehicle, in addition to those listed above, there are other two operation modes that are: increase the engine torque during the acceleration and recovering the energy during braking phase. Among the various types of electrical machines existing in the market, the permanent magnet synchronous machines take up an important position in the cogeneration and
hybrid vehicle fields. In fact, this kind of electric machine allows to obtain: a high performance, high torque density, high overload capacity, a good robust construction, compact volume, and therefore low weight. Furthermore this type of electric machine can work at variable speeds and operate as motor and as generator with comparable performance.
For this reason in this Ph.D. thesis the electrical drives composed by an internal combustion engines direct connected to permanent magnet synchronous electric machines will be presented.
The author’s doctoral thesis has been carried out at the Electric Drive Laboratory of University of Padova, which since more than twenty years is active in the design of electrical machines and their control through research projects with industrial partners and scientific publications in journals and in international conferences. Therefore, although in the literature there are several books discussing an electric drives, thanks to the experience acquired in this laboratory the author intention is to emphasize with greater detail the aspects and basic notions which in his opinion are fundamental to the design of on electric drive devoted to the applications subject of this work.
In addition, in the opinion of the author, unlike a paper on journal or conference the doctoral thesis should be reasonably self-contained and should be understandable even by a non expert of this field of research; therefore also basic aspects of an electric drive and its control have been reported with detail.
So the work reported in this thesis is essentially composed by two parts, the first part is made up by the first four Chapters and the second one is composed by the last two Chapters.
In the first part of Ph.D. thesis the basic aspects, that are required for a good knowledge on the electric drives field, have been reported. In particular the design aspects and fundamental characteristics of electric machine control, operating limits of a permanent magnet synchronous machine, and power converter have been pointed out. The second part of Ph.D. thesis is focused on the design aspects of electric drive for a domestic cogeneration system and for hybrid electric motorcycle. In particular for CHP system some effective techniques, that can help to reduce the vibration and noise problems due to the internal combustion engine, have been described. In the field of hybrid electric motorcycle the main design choices carried out in order to achieve a hybrid electric motorcycle prototype with good performance are reported.In questi ultimi anni l’aumento del costo del petrolio e il riscaldamento globale della terra dovuto ai gas serra ha spinto il settore scientifico, i governi e quindi il mercato nella direzione di una più alta efficienza dei sistemi con lo scopo di ridurre l’utilizzo di questo combustibile e quindi le sue emissioni di CO2 associate. Oggigiorno i settori più coinvolti in questa rivoluzione tecnologica sono il settori della generazione di energia elettrica e il settore dei trasporti. Infatti questi due settori sono i principali responsabili di emissioni di CO2 globali della terra che sono associate per circa il 45% alla generazione elettrica e per circa 30% ai trasporti. Inoltre va ricordato che sebbene il petrolio non sia una fonte di energia rinnovabile attualmente circa il 40% dell’energia mondiale dipende dal petrolio e questo livello di dipendenza sale a circa 80% nel settore dei trasporti dove la maggior parte dei veicoli è spinta da un motore alimentato da derivati del petrolio. Per questi motivi la ricerca scientifica negli ultimi dieci anni si sta concentrando su questi problematiche in particolare nei settori emergenti quali cogenerazione distribuita e veicoli ibridi. In particolare vengono studiati nuovi impianti di energia distribuita capaci di aumentare l’efficienza energetica producendo in maniera combinata energia elettrica e termica direttamente dove richiesta e solo se necessaria in questo modo si riducendo le perdite di rete. Nel settore dei veicoli ibridi invece l’utilizzo del motore elettrico può aiutare ad aumentare l’efficienza del motore termico nei vari punti di lavoro, questi sistemi consentono infatti di migliorare fino al 30% le prestazioni in termini di consumi ed emissioni rispetto ad un veicolo tradizionale. Con questo contesto storico la tesi si è focalizzata nello studio di una struttura della catena di potenza di un veicolo o di un sistema di cogenerazione di piccola taglia ossia l’analisi di un sistema composto da un motore endotermico direttamente calettato con una macchina elettrica. La macchina elettrica viene generalmente utilizzata con due funzioni principali: avviare il motore a combustione e generare energia elettrica. Nel caso di un veicolo ibrido vi sono altre due funzioni che si aggiungono a quelle appena elencate ossia la fase di incremento di coppia durante le accelerazioni e una fase di recupera di energia durante le frenate. Tra le varie tipologie di macchine elettriche esistenti nel mercato, le macchine sincrone a magnete permanente occupano un posto di rilievo in questi settori. Infatti questa tipologia di macchina elettrica consente di ottenere: un alto rendimento, un’alta densità di coppia, notevole capacità di sovraccarico, una buona robustezza costruttiva, volumi compatti e quindi peso ridotto. Inoltre questo tipo di macchina può lavorare a velocità variabile e può operare con prestazioni aragonabili sia come motore che come generatore. Per questo motivo nella tesi verranno presentati azionamenti elettrici basati su motori a combustione interna calettati a macchine elettriche sincrone a magneti permanenti. La tesi di dottorato dell’autore è stata svolta presso il laboratorio di azionamenti elettrici di Padova, il quale da più di venti anni è attivo nel campo della progettazione di macchine elettriche e del loro controllo mediante progetti di ricerca con partner industriali e pubblicazioni scientifiche su riviste e su conferenze internazionali. Quindi sebbene siano presenti in letteratura molti libri che parlano di azionamenti elettrici grazie all’esperienza dell’autore maturata in questo laboratorio l’autore ha voluto enfatizzare con maggiore dettaglio gli aspetti e le nozioni che secondo la sua opinione sono fondamentali per la progettazione di un azionamento elettrico. Inoltre secondo il parere dell’autore al tesi di dottorato a differenza di un articolo su conferenza o su rivista deve essere autonoma e deve poter essere compresa anche da un non esperto del settore pertanto sono stati riportati con dettaglio anche aspetti base di una azionamento elettrico e del controllo motore. Quindi il lavoro riportato in questa tesi di dottorato è diviso sostanzialmente in due parti la prima composta dai primi quattro capitoli e la seconda parte composta dagli ultimi due capitoli. Nella prima parte sono state riportate le nozioni fondamentali necessarie per una buona conoscenza sul settore degli azionamenti elettrici in particolare nella parte di controllo motore, limiti di funzionamento di un motore sincrono a magneti permanenti e inverter di potenza. Mentre la seconda parte si è focalizzata sulla descrizione della progettazione di un azionamento per un sistema di cogenerazione domestica e per motociclette ibride. Nell’ambito della cogenerazione sono state descritte alcune tecniche che consentono di ridurre il problema delle vibrazioni dovute al motore a combustione interna. Nel settore della motocicletta ibrida sono state mostrate le principali scelte di progettazione effettuate per realizzare un prototipo efficace e funzionante di motocicletta ibrida.
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Rolong, Andrea. "Tissue Engineered Scaffolds and Three Dimensional Tumor Constructs to Evaluate Pulsed Electric Field Treatments." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/97320.
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This work investigates the use of irreversible electroporation (IRE) for tissue engineering applications and as a cancer ablation therapy. IRE uses short, high-intensity electric pulses to create pores in a cell's membrane and disrupt its stability. At a certain energy level, damage to the cell becomes too great and it leads to cell death. The particular mechanisms that drive this response are still not completely understood. Thus, further characterization of this behavior for cell death induced by pulsed electric fields (PEFs) will advance the understanding of these types of therapies and encourage their use to treat unresectable tumors that can benefit from the non-thermal mechanism of action which spares critical blood vessels and nerves in the surrounding area. We evaluate the response to PEFs by different cell types through experimental testing combined with computer simulations of these treatments. We show that IRE can be used to kill a specific type of bacteria that produce cellulose which can be used as an implantable material to repair damaged tissues. By killing these bacteria at particular times and locations during their cellulose production, we can create conduits in the overall structure of this material for the transport of oxygen and nutrients to the cells within the area after implantation. The use of tissue models also plays a key role in the investigation of various cancer treatments by providing a controlled environment which can mimic the state of cells within a tumor. We use tumor models comprised of a mix of collagen and cancer cells to evaluate their response to IRE based on the parameters that induce cell death and the time it takes for this process to occur. The treatment of prostate and pancreatic cancer cells with standard monopolar (only positive polarity) IRE pulses resulted in different time points for a full lesion (area of cell death) to develop for each cell type. These results indicate the presence of secondary processes within a cell that induce further cell death in the border of the lesion and cause the lesion to increase in size several hours after treatment. The use of high-frequency irreversible electroporation (H-FIRE)--comprised of short bursts of high-intensity, bipolar (both positive and negative polarity) pulses--can selectively treat cancer cells while keeping healthy cells in the neighboring areas alive. We show that H-FIRE pulses can target tumor-initiating cells (TICs) and late-stage, malignant cancer cells over non-malignant cells using a mouse ovarian cancer model representative of different stages of disease progression. To further explore the mechanisms that drive this difference in response to IRE and H-FIRE, we used more complex tumor models. Spheroids are a type of 3D cell culture model characterized by the aggregation of one or more types of cells within a single compact structure; when embedded in collagen gels, these provide cell-to-cell contact and cell-to-matrix adhesion by interactions of cells with the collagen fibers (closely mimicking the tumor microenvironment). The parameters for successful ablation with IRE and H-FIRE can be further optimized with the use of these models and the underlying mechanisms driving the response to PEFs at the cellular level can be revealed.Ph. D.
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Ramadoss, Balaji. "Ontology Driven Model for an Engineered Agile Healthcare System." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5110.
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Healthcare is in urgent need of an effective way to manage the complexity it of its systems and to prepare quickly for immense changes in the economics of healthcare delivery and reimbursement. Centers for Medicare & Medicaid Services (CMS) releases policies affecting inpatient and long-term care hospitals policies that directly affect reimbursement and payment rates. One of these policy changes, a quality-reporting program called Hospital Inpatient Quality Reporting (IQR), will effect approximately 3,400 acute-care and 440 long-term care hospitals. IQR sets guidelines and measures that will contain financial incentives and penalties based on the quality of care provided. CMS, the largest healthcare payer, is aggressively promoting high quality of care by linking payment incentives to outcomes. With CMS assessing each hospital's performance by comparing its Quality Achievements and Quality Improvement scores, there is a growing need and demand to understand these quality measures under the context of patient care, data management and system integration. This focus on patient-centered quality care is difficult for healthcare systems due to the lack of a systemic view of the patient and patient care. This research uniquely addresses the hospital's need to meet these challenges by presenting a healthcare specific framework and methodology for translating data on quality metrics into actionable processes and feedback to produce the desired quality outcome. The solution is based on a patient-care level process ontology, rather than the technology itself, and creates a bridge that applies systems engineering principles to permit observation and control of the system. This is a transformative framework conceived to meet the needs of the rapidly changing healthcare landscape. Without this framework, healthcare is dealing with outcomes that are six to seven months old, meaning patients may not have been cared for effectively. In this research a framework and methodology called the Healthcare Ontology Based Systems Engineering Model (HOB-SEM) is developed to allow for observability and controllability of compartmental healthcare systems. HOB-SEM applies systems and controls engineering principles to healthcare using ontology as the method and the data lifecycle as the framework. The ontology view of patient-level system interaction and the framework to deliver data management and quality lifecycles enables the development of an agile systemic healthcare view for observability and controllability
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Chan, Sau-ha. "Tradeoff between internal combustion engined vehicles and electric vehicles in Hong Kong /." Hong Kong : University of Hong Kong, 1995. http://sunzi.lib.hku.hk/hkuto/record.jsp?B17092267.
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Azu, Nene Akunor. "A comparison of the operating envelopes of diesel-fueled truck engines and hybrid electric bus engines to the federal testing procedure cycle." Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=2108.
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Thesis (M.S.)--West Virginia University, 2001.Title from document title page. Document formatted into pages; contains xi, 88 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 84-85).
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VASCHETTO, SILVIO. "Design and development of permanent magnet synchronous machines shaft-line embedded in aeronautic engines." Doctoral thesis, Politecnico di Torino, 2011. http://hdl.handle.net/11583/2615701.
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Technological advances in the aerospace industry have improved aircraft efficiency and reduced the cost of air transport, leading since 1960 to a continuous growth of the worldwide air traffic. Today it is postulated that also into the foreseeable future both the passenger and cargo air traffic will continue to growth, increasing the CO2 air transport emissions. In this contest, there are many environmental as well as commercial pressures on aircraft manufacturers to improve performances of future aircraft in terms of safety, air pollution, noise and climate change.
To achieve these goals, it is necessary revisiting the whole aircraft architecture system, with the introduction of new technologies for performing key functions on aircraft.
Today the conventional civil aircraft are characterized by four different secondary power distribution systems: mechanical, hydraulic, pneumatic and electrical. This implies a complex power distribution nets aboard, and the necessity of an appropriate redundancy of each of them. In order to reduce this complexity, with the aim to improve efficiency and reliability, the aerospace designer community trend is towards the `More Electric Aircraft (MEA)' concept, that is the wider adoption of electrical systems in preference to the others.
This solution involves an increase of the aircraft electrical loads and, as a consequence, heavy implications for the on-board electrical generation systems are predictable. The resulting increase of the electrical power requirements encourage the research of alternative solutions rather than simply scaling up existing technologies such as generators driven by gearboxes. To address these challenges, many studies are in the direction of the so called `More Electric Engine (MEE)', in which the electrical machines are integrated inside the main gas turbine engine to generate electrical power, start the engine and guarantee safety generation in case of a critical on-flight failure. In this way the mechanical gearbox which connects the actual generators to the aeroengine shaft can be eliminated.
The MEA and the MEE concept can be considered as an evolutionary implementation of the `All Electric Aircraft (AEA)', in which all the aircraft on-board systems are supplied in an electrical form. The MEE concept will involve important mechanical and thermodynamic implications in the aeroengine design, making necessary a preliminary system analysis on today conventional aeroengine, in order to evaluate the integration feasibility with the actual mechanical and environmental constraints. The electrical machines can be integrated inside the engine in some different positions, either in the front part before the combustion chamber, in particular in the low-pressure or in the high-pressure compressor stages, or in the rear part of the engine, in the tail-cone zone.
In the frame of the GREAT2020 (GReen Engine for Air Transport in 2020) project co-founded by Regione Piemonte, aimed to the development of new eco-compatible aircraft engines for the entry into service in 2020, the MEE concept focus is on the evaluation of the most suitable solution between four possible integration positions in the front part of the today conventional two-shaft GEnx turbofan engine. The rotational speeds and the maximum available volumes are respectively imposed by the shaft connection and by the available spaces inside the aeroengine.
In the purpose of the MEE concept on which the work presented in this dissertations is based, in order to evaluate the less critical solution between the proposed, a trade-off study conducted on preliminary electromagnetic design has been performed considering both radial and axial flux surface mounted permanent magnet synchronous machines. The comparison of the different solutions have been done on the base of same sizing indexes.
Due to the particular application in which the electrical machine integration is involved, in order to evaluate impact on the whole system performance, a wider trade-off study concerning the overall aeroengine system has been done by the aerospace company Avio, partner of the GREAT2020 project.
The focus of the work presented in this dissertation, is the development of appropriate tools to perform a preliminary electromagnetic design of radial and axial flux, surface mounted, permanent magnet synchronous machines with three-phase distributed and single-layer fractional-slot non-overlapping concentrated windings. In particular, this latter winding topology has been considered for its specific application for its shorter end-winding connections respect to the distributed layout, and for their high fault tolerant capability due to the electrical and physical separation between the phases which reduces the possibility of a fault propagation.
Regarding the radial flux topologies, both inner and outer rotor machine structures have been considered; for the axial flux machines the single-stage (one stator and one rotor) as well as the multi-stage structures, obtained connecting on the same axis more than one single-stage structure, have been considered.
The developed general purpose tools are based on simple geometrical approach using conventional design equations. The geometrical dimensions are computed starting from the design specifications and material utilization indexes imposed by the designer. The implemented codes would be a useful tool for the electrical machine designer in order to quickly define a preliminary electromagnetic design starting from a fresh sheet of paper. The conducted comparisons with commercial software have proved the validity of the tools for the conducted MEE trade-off study; however, in a prototype design aimed to the construction, detailed analysis using commercial software available on the market and Finite Element Method analysis have to be done in order to verify and improve in details the preliminary electromagnetic design obtained by the implemented codes.
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Botha, Johannes Rudolf. "Design of an RF ion thruster." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86267.
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Thesis (MEng)--Stellenbosch University, 2014.ENGLISH ABSTRACT: Recent years have seen a decline in the rate of space exploration due to the inefficiency of chemical rockets. Therefore alternative fuel efficient propulsion methods are being sought to enable cost effective deep space exploration. The high fuel efficiency of electric thrusters enable a spacecraft to travel further, faster and cheaper than any other propulsion technology available. Thus electric propulsion has become the propulsion of choice for scientists and engineers. A typically electric thruster contains some sort of electrode to ionise the propellant. Although this is feasible for short space missions, it becomes impractical for more ambitious space missions as electrodes erode over time. The alternative is to ionise the propellant using electromagnetic fields, which eliminates lifespan issues associated with electrode based thrusters. In order to examine methods of improving the lifespan and performance of electric thrusters, this thesis aimed to study the method of microwave discharge ionisation for an electric thruster. This includes the design of an RF Ion Thruster with extraction and acceleration grids to generate thrust. A 600 W 2.45 GHz magnetron (obtained from a conventional microwave oven), coupled to circular TM010 resonant cavity, was used to ionise neutral argon gas. The process of electron cyclotron resonance (ECR) was used to ensure the efficient ionisation of a high density plasma. The thrust was achieved with a three-grid system biased at high voltages to accelerate positively charged argon ions to high exhaust velocities. Results yielded the success of the designed electromagnetic based thruster, measuring approximatively 1.78 mN of thrust with a specific impulse of Isp = 3786 seconds. The ECR process produced a high plasma density with a plasma absorption rate of approximately 77% of the total input microwave power. The final results obtained were found to match the predicted results extremely well and resembled results found in literature. This demonstrates the efficiency of the RF ion thruster that was designed in this project and the future use in space exploration activities. However, future research needs to be undertaken on a controlled feedback system that will ensure optimal operating conditions for maximum performance. In addition, the method of grid-less acceleration needs to be studied to achieve maximum thrust and specific impulse.
AFRIKAANSE OPSOMMING: In onlangse jare het ’n afname in die tempo van die verkenning van die ruimte dit te danke aan die ondoeltreffendheid van chemiese vuurpyle. Derhalwe moet alternatiewe brandstof aandrywing metodes ondersoek word, om koste-effektiewe diep ruimte-eksplorasie moontlik te maak. Die hoë brandstof-doeltreffendheid van elektriese ontbranders stel ’n ruimtetuig in staat om verder, vinniger en goedkoper te reis as enige ander aandrywing tegnologie wat tans beskikbaar is. Dus het elektriese aandrywing metodes die aandrywings keuse vir wetenskaplikes en ingenieurs geword. ’n Tipies elektriese vuurpyl/aandrywer bevat ’n vorm van elektrode om die brandstof (argon gas) te ioniseer. Alhoewel hierdie elektrode proses van ionisasie effektief is vir kort ruimte missies, word dit onprakties vir meer ambisieuse ruimte missies as gevolg van verweering van elektrodes met verloop van tyd. ’n Alternatief is om die dryfmiddel/brandstof te ioniseer deur gebruik te maak van elektromagnetiese velde. Die elekromagnetiese velde sal die lewensduur van die vuurpyl vermeerder deur die verweering van elektrodes, wat geassosieer word met tipiese elektrieses vuurpyle, te elimineer. Hierdie tesis se doelwit is om die metode van mikrogolf ontslag ionisasie vir ’n elektriese vuurpyl/aandrywer te bestudeer om ten einde die lewensduur en doeltreffendheid van elektriese vuurpyl/aandrywer te ondersoek. Dit sluit in die ontwerp van ’n radio frekewensie ioon vuurpyl/aandrywer met ’n ontginning en versnelling matriks/rooster om stukrag te genereer. ’n 2,45 GHz magnetron (verkry vanaf ’n konvensionele mikrogolfoond), gekoppel aan ’n TM010 resonante holte, was gebruik om neutrale argon gas te ioniseer. Die proses van elektron siklotron resonansie (ESR) was gebruik om die doeltreffende ionisasie van ’n hoë digtheid plasma te verseker. Die aandrywing/stukrag was behaal met ’n drie-matriks-stelsel, bevoordeel deur hoë spannings om die positief-gelaaide argon ione te versnel. Resultate opgelewer, het die sukses van die ontwerp van ’n elektromagnetiese gebaseerde vuurpyl/aandrywer met ’n benaderde meting van ongeveer 1.78 mN van stukrag/aandrywing met ’n spesifieke impuls van Isp = 3786 sekondes bewys. Die ECR proses het ’n hoë plasma digtheid geproduseer met ’n plasma opname persentasie van ongeveer 77% van die totale inset mikrogolf energie. Die finale uitslae wat verkry was, het bevind dat die voorspelde resultate baie goed inpas met resultate in beskikbare literatuur. Dit dui op die doeltreffendheid van die RF ioon vuurpyl/aandrywer wat ontwerp is in hierdie projek vir die toekomstige gebruik in ruimte eksplorasie-aktiwiteite. Toekomstige navorsing moet op ’n beheerde terugvoer sisteem onderneem word, wat optimale werktoestande verseker vir maksimum prestasie. Daarbenewens moet die metode van matriks-lose versnelling bestudeer word, om maksimum versnelling/stukrag en spesifieke impuls te verseker.
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Chung, Jae-Young. "Broadband Characterization Techniques for RF Materials and Engineered Composites." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1269542888.
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Kerai, Hiren, and Andrej Verem. "Physically Based Models for Predicting Exhaust Temperatures in SI Engines." Thesis, Linköpings universitet, Fordonssystem, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-129029.
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To have knowledge about the gas and material temperatures in the exhaust system of today's vehicles is of great importance. These temperatures need to be known for component protection, control- and diagnostic purposes. Today mostly map-based models are used which are not accurate enough and difficult to tune since it consist of many parameters. In this thesis physically based models are developed for several components in the exhaust system. The models are derived through energy balances and are more intuitive compared to the current map-based models. The developed models are parameterized and validated with measurements from wind tunnel experiments and driving scenarios on an outdoor track. The engine out model is modeled theoretically and is therefore not parameterized or validated. The model for the temperature drop over the exhaust manifold could not be validated due to the pulsations occurring in the exhaust manifold, however suggestions on how to solve this problem are given in this report. The models for the turbocharger, the catalyst and the downpipe are parameterized and validated with good results in this thesis. The mean absolute error for the validation data set for the turbocharger is 0.46 % and 1.01 % for the catalyst. The mean absolute percentage error for the downpipe is 1.07 %.
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Jung, Kyung Young. "Full-wave modeling and analysis of dispersion-engineered materials and plasmon waveguides." The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1218503761.
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Nandkumar, Subhash. "Two-stroke linear engine." Morgantown, W. Va. : [West Virginia University Libraries], 1998. http://etd.wvu.edu/templates/showETD.cfm?recnum=153.
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Thesis (M.S.)--West Virginia University, 1998.Title from document title page. Document formatted into pages; contains x, 82 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 69-70).
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Nahar, Niru Kamrun. "Photonic Crystal Fibers and Optical True Time Delay Engines for Wideband Arrays." The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1213624105.
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Morales, Cesar A. "Magneto-Dielectric Polymer Nanocomposite Engineered Substrate for RF and Microwave Antennas." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3255.
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This dissertation presents the first reported systematic investigation on the implementation of multilayer patch antennas over Fe3O4-based polymer nanocomposite (PNC) magneto-dielectric substrates. The PNC substrate is created by the monodispersion of Fe3O4 nanopthesiss, with mean size of 7.5nm, in a polymeric matrix of Polydimethylsiloxane (PDMS).
Recently, magneto-dielectric substrates have been proposed by several researchers as a means for decreasing the size and increasing the bandwidth of planar antennas. Nevertheless, factors such as high loss and diminished control over magnetic and dielectric properties have hindered the optimal performance of antennas. In addition, the incompatibility and elevated complexity prevents integration of conventional magnetic materials with antennas and standard fabrication processes at printed circuit boards (PCBs) and wafer levels. Additionally, the low hysteresis losses exhibited by uniformly embedded superparamagnetic nanopthesiss complemented by the ease of integration of polymer nanocomposites in standard fabrication processes, offer promising solutions to resolve any of the complications and concerns foresaid.
Towards this dissertation work, one multilayer antenna was constructed over a molded PDMS substrate along with three similar antennas built on PDMS-Fe3O4 PNC substrates with different Fe3O4 nanopthesis loading concentrations in the PDMS matrix of 80%, 50% and 30% by weight. This pioneering work in the experimental implementation and characterization of magneto-dielectric PNC antennas has not only resulted in antennas with different operational frequencies in the 3-5GHz band, but also expanded our knowledge base by correlating the concentration of magnetic nanopthesiss to key antenna performance metrics such as antenna bandwidth, antenna efficiency and miniaturization factors.
Among the most significant results a magneto-dielectric antenna with maximum miniaturization factor of 57%, and a 58% increase in bandwidth, whilst retaining an acceptable antenna gain of 2.12dBi, was successfully demonstrated through the deployment of molded PDMS-Fe3O4 PNC substrate under external DC bias magnetic fields.
This dissertation also presents a versatile process for constructing flexible and multilayer antennas by the seamless incorporation of a variety of materials such as PDMS, Liquid Crystal Polymer (LCP) laminates, metal clads and molded magneto-dielectric polymer nanocomposites with evenly embedded magnetic nanopthesiss.
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Cawthorne, William R. "Optimization of a brushless permanent magnet linear alternator for use with a linear internal combustion engine." Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=800.
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Thesis (Ph. D.)--West Virginia University, 1999.Title from document title page. Document formatted into pages; contains vi, 112 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 76-79).
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Gershlak, Joshua R. "Electrically Conducting Biofibers: Approaches to Overcome the Major Challenges in the Clinical Translation of a Tissue Engineered Cardiac Patch." Digital WPI, 2018. https://digitalcommons.wpi.edu/etd-dissertations/499.
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Cardiovascular disease is the leading cause of death in the United States, accounting for approximately 25% of total deaths. Myocardial infarction (MI) is an extreme case of cardiovascular disease where ischemia leads to irreversible tissue necrosis. As the heart lacks the capacity to endogenously regenerate, the infarcted region is negatively remodeled, reducing cardiac function. Current therapies are not able to regenerate cardiac function post-MI, requiring novel approaches such as tissue engineering. However, there are three major pitfalls that are currently limiting the clinical translation of a tissue engineered cardiac patch: lack of proper vascularization within the tissues; biocompatible material; and lack of electrical integration between engineered tissue and host. The research within this dissertation aimed to engineer solutions to overcome these three pitfalls.
Plants and animals exploit fundamentally different approaches to transporting fluids, yet there are surprising structural similarities. To take advantage of these similarities, we looked across different kingdoms and investigated whether plants and their innate vasculature could serve as perfusable scaffolds for tissue engineering. Standard perfusion decellularization techniques were adapted and applied to spinach leaves, which were found to be fully devoid of DNA following processing. Leaf vasculature remained patent post-decellularization and supported transport of various sized microparticles. Human cells successfully seeded onto and inside the plant scaffolds. Decellularized leaves were found to be nearly void of any cytotoxic affects. Leaf biocompatibility was then investigated in vivo through subcutaneous implantation in a rat model. Leaf scaffolds were found to be biocompatible after 4 weeks of implantation. Furthermore, leaves that were pre-functionalized with an RGD-dopamine peptide were fully integrated into the host tissue within one week. This shows the leaf scaffold’s potential to be an immuno-modulatory material, depending upon the intended application.
Electrically conducting biofibers were engineered through the combination of fibrin microthreads and engineered conductive HEK293 cells. Biofibers could act as a modular platform to allow for electrical integration between the host tissue and any engineered cardiac patch. Biofibers directionally carried electrical current and were found capable of bridging electrical signal between two separate clusters of cardiomyocytes. In vivo investigation bridging a biofiber from the left atria to the left ventricle was accomplished in a rat model. Electrical maps demonstrated a visible accessory pathway that created a feedback electrical signal from the ventricle to the atria through the implanted biofiber. These results demonstrate electrical integration in vivo between host myocardium and the engineered biofiber.
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Thornberg, Nils, and Kraft Jonas Eriksson. "Physically Based Modelling for Knock Prediction in SI Engines." Thesis, Linköpings universitet, Fordonssystem, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-149020.
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The high demand for an increase in performance and at the same time loweringthe emissions is forcing the automotive industry to increase the efficiency of thevehicles. This demand lead to a problem called knock, which often is the limitingfactor when increasing the efficiency of the engine. Knock occurs when theunburned gases inside the combustion chamber self-ignites due to the increasingpressure and temperature.This thesis investigates if it is possible to predict knock with a physicallybased knock model. The model consist of several sub-models such as pressuremodel, temperature model and knock model. The models are built by using measureddata and the goal is to get an independent knock prediction model that canfind the limited ignition angle that will cause knock.The results shows that an analytic pressure model can simulate a measuredpressure curve. But when it comes to predicting knock, there is an uncertaintywhich can be improved by changing the modelling strategy and making the modelsmore accurate.
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Al-Hamdan, Qusai Zuhair Mohammed. "Design criteria and performance of gas turbines in a combined power and power (CPP) plant for electrical power generation." Thesis, University of Hertfordshire, 2002. http://hdl.handle.net/2299/14041.
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The simple gas turbine engine Operates on the basic Joule-Brayton cycle and it is notorious for its poor thermal efficiency. Several modifications have been made to the simple cycle in order to increase its thermal efficiency but, within the thermal and mechanical stress constrains, the efficiency still ranges between 28 and 35%. However, higher values of energy utilisation efficiency have been claimed in recent years by using low grade heat from the engine exhaust either for district heating or for raising low pressure steam for chemical processes. Both applications are not very attractive in hot countries. The concept of using the low grade thermal energy from the gas turbine exhaust to raise steam in order to drive a steam turbine and generate additional electricity, i. e. the combined power and power or CPP plant would be more attractive in hot countries than the CHP plant. It was hypothesized that the operational parameters, hence the performance of the CPP plant, would depend on the allowable gas turbine entry temperature. Hence, the exhaust gas temperature could not be decided arbitrarily. This thesis deals with the performance of the gas turbine engine operating as a part of the combined power and power plant. In a CPP plant, the gas turbine does not only produce power but also the thermal energy that is required to operate the steam turbine plant at achievable thermal efficiency. The combined gas turbine-steam turbine cycles are thermodynamically analysed. A parametric study for different configurations of the combined gas-steam cycles has been carried out to show the influence of the main parameters on the CPP cycle performance. The parametric study was carried out using realistic values in view of the known constraints and taking into account any feasible future developments. The results of the parametric study show that the maximum CPP cycle efficiency would be at a point for which the gas turbine cycle would have neither its maximum efficiency nor its maximum specific work output. It has been shown that supplementary heating or gas turbine reheating would decrease the CPP cycle efficiency; hence, it could only be justified at low gas turbine inlet temperatures. Also it has been shown that although gas turbine intercooling would enhance the performance of the gas turbine cycle, it would have only a slight effect on the CPP cycle performance. A graphical method for studying operational compatibility, i.e. matching, between gas turbine components has been developed for a steady state or equilibrium operation. The author would like to submit that the graphical method offers a novel and easy to understand approach to the complex problem of component matching. It has been shown that matching conditions between the compressor and the turbine could be satisfied by superimposing the turbine performance characteristics on the compressor performance characteristics providing the axes of both were normalised. This technique can serve as a valuable tool to determine the operating range and the engine running line. Furthermore, it would decide whether the gas turbine engine was operating in a region of adequate compressor and turbine efficiencies. A computer program capable of simulating the steady state off-design conditions of the gas turbine engine as part of the CPP plant has been developed. The program was written in Visual Basic. Also, another program was developed to simulate the steady state off-design operation of the steam turbine power plant. A combination of both programs was used to simulate the combined power plant. Finally, it could be claimed that the computer simulation of the CPP plant makes significant contribution to the design of thermal power plants as it would help in investigating the effects of the performance characteristics of the components on the performance of complete engines at the design and off-design conditions. This investigation of the CPP plant performance can be carried out at the design and engineering stages and thus help to reduce the cost of manufacturing and testing the expensive prototype engines.
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Castro, Juan De Dios. "Engineered Nanocomposite Materials for Microwave/Millimeter-Wave Applications of Fused Deposition Modeling." Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/6643.
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A variety of high-permittivity (high-k) and low-loss ceramic-thermoplastic composite materials as fused deposition modeling (FDM) feedstock, based on cyclo-olefin polymer (COP) embedded with sintered ceramic fillers, have been developed and investigated for direct digital manufacturing (DDM) of microwave components. The composites presented in this dissertation use a high-temperature sintering process up to 1500°C to further enhance the dielectric properties of the ceramic fillers. The electromagnetic (EM) properties of these newly developed FDM composites were characterized up to the Ku-band by using the cavity perturbation technique. Several models for prediction of the effective relative dielectric permittivity of composites based on the filler loading volume fraction have been evaluated, among which Hanai-Bruggeman and Maxwell models have shown the best accuracy with less than 2% and 5% discrepancies, respectively.
The 30 vol. % COP-TiO2 FDM-ready composites with fillers sintered at 1200°C have exhibited a relative permittivity (εr) of 4.78 and a dielectric loss tangent (tan δd) lower than 0.0012 at 17 GHz. Meanwhile, the 30 vol. % COP-MgCaTiO2 composites with fillers sintered at 1200°C have exhibited a εr of 4.82 and a tan δd lower than 0.0018. The DDM approach combines FDM of the engineered EM composites and micro-dispensing for deposition of conductive traces to fabricate by 3D-printing edge-fed patch antennas operating at 17.2 GHz and 16.5 GHz. These antennas were demonstrated by employing a 25 vol. % COP-MgCaTiO2 composite FDM filament with the fillers sintered at 1100°C and a pure COP filament, which were both prepared and extruded following the process described in this dissertation. The low dielectric loss of the 25 vol. % COP-MgCaTiO2 composite material (tan δd lower than 0.0018) has been leveraged to achieve a peak realized gain of 6 dBi. Also, the high-permittivity (εr of 4.74), which corresponds to an index of refraction of 2.17, results in a patch area miniaturization of 50% when compared with an antenna designed and DPAM-printed over a Rogers RT/duroid® 5870 laminate core through micro-dispensing of CB028 silver paste. This reference antenna exhibited a measured peak realized gain of 6.27 dBi that is comparable.
Also, two low-loss FDM-ready composite materials for DDM technologies are presented and characterized at V-band mm-wave frequencies. Pure COP thermoplastic exhibits a relative permittivity εr of 2.1 and a dielectric loss tangent tan δd below 0.0011 at 69 GHz, whereas 30 vol. % COP-MgCaTiO2 composites with fillers sintered at 1200°C exhibit a εr of 4.88 and a tan δd below 0.0070 at 66 GHz. To the best of my knowledge, these EM properties (combination of high-k and low-loss) are superior to other 3D-printable microwave materials reported by the scientific microwave community and are on par with materials developed for high-performance microwave laminates by RF/microwave industry as shown in Chapter 5 and Chapter 7 and summarized in Table 5.4 and Table 7.1. Meanwhile, the linear coefficient of thermal expansion (CTE) from -25°C to 100°C of the reinforced 30 vol. % COP-MgCaTiO2 composite with fillers sintered at 1200°C is 64.42 ppm/°C, which is about 20 ppm/°C lower when compared with pure ABS and 10 ppm/°C lower as compared to high-temperature polyetherimide (PEI) ULTEM™ 9085 resin from Stratasys, Ltd. The CTE at 20°C of the same composite material is 84.8 ppm/°C which is about 20 ppm/°C lower when compared with pure ABS that is widely used by the research community for 3D printed RF/microwave devices by FDM. The electromagnetic (EM) composites with tailored EM properties studied by this work have a great potential for enabling the next generation of high-performance 3D-printed RF/microwave devices and antennas operating at the Ku-band, K-band, and mm-wave frequencies.
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Bowman, David C. "Image Stitching and Matching Tool in the Automated Iterative Reverse Engineer (AIRE) Integrated Circuit Analysis Suite." Wright State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=wright1533766175549951.
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Houdyschell, David. "A diesel two-stroke linear engine." Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1312.
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Thesis (M.S.)--West Virginia University, 2000.Title from document title page. Document formatted into pages; contains ix, 64 p. : ill. (some col.) Includes abstract. Includes bibliographical references (p. 42-43).
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Chan, Sau-ha, and 陳秀霞. "Tradeoff between internal combustion engined vehicles and electric vehicles in Hong Kong." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1995. http://hub.hku.hk/bib/B31253064.
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Al-Durra, Ahmed Abad. "MODEL-BASED ESTIMATION FOR IN-CYLINDER PRESSURE OF ADVANCED COMBUSTION ENGINES." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1281715345.
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Berggren, Henrik, and Martin Melin. "UKF and EKF with time dependent measurement and model uncertainties for state estimation in heavy duty diesel engines." Thesis, Linköpings universitet, Fordonssystem, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-69229.
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The continuous challenge to decrease emissions, sensor costs and fuel consumption in diesel engines is battled in this thesis. To reach higher goals in engine efficiency and environmental sustainability the prediction of engine states is essential due to their importance in engine control and diagnosis. Model output will be improved with help from sensors, advanced mathematics and non linear Kalman filtering. The task consist of constructing non linear Kalman Filters and to adaptively weight measurements against model output to increase estimation accuracy. This thesis shows an approach of how to improve estimates by nonlinear Kalman filtering and how to achieve additional information that can be used to acquire better accuracy when a sensor fails or to replace existing sensors. The best performing Kalman filter shows a decrease of the Root Mean Square Error of 75 % in comparison to model output.
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Lindén, Erik, and David Elofsson. "Model-based turbocharger control : A common approach for SI and CI engines." Thesis, Linköpings universitet, Institutionen för systemteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-70288.
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In this master’s thesis, a turbine model and a common control structure for theturbocharger for SI and CI-engines is developed. To design the control structure,simulations are done on an existing diesel engine model with VGT. In order tobe able to make simulations for engines with a wastegated turbine, the model isextended to include mass flow and turbine efficiency for that configuration. Thedeveloped model has a mean absolute relative error of 3.6 % for the turbine massflow and 7.4 % for the turbine efficiency. The aim was to control the intake manifoldpressure with good transients and to use the same control structure for VGTand wastegate. By using a common structure, development and calibration timecan be reduced. The non-linearities have been reduced by using an inverted turbinemodel in the control structure, which consists of a PI-controller with feedforward.The controller can be tuned to give a fast response for CI engines and a slowerresponse but with less overshoot for SI engines, which is preferable.
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Avram, Remus C. "A UNIFIED NONLINEAR ADAPTIVE APPROACH FOR THE FAULT DIAGNOSIS OF AIRCRAFT ENGINES." Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1332784433.
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Liu, Yuxing. "Systematic Optimization and Control Design for Downsized Boosted Engines with Advanced Turbochargers." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1405764571.
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Deetlefs, Ivan Niell. "Design, simulation, manufacture and testing of a free-piston Stirling engine." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/95922.
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Thesis (MEng) -- Stellenbosch University, 2014.ENGLISH ABSTRACT: The aim of this study was to design and manufacture an experimentally testable free-piston Stirling engine (FPSE), including a linear electric generator; to develop and validate a theoretical simulation model; to identify problem areas pertaining to its manufacture; and finally to assess the work undertaken, to lay out the groundwork for the future development of a 3 kWe FPSE suitable for incorporation in a solar Stirling dish power generator. A redesigned version of the Beale B- 10B demonstrator engine was manufactured to overcome design diffculties and to simplify testing. The design made use of an electric generator designed at the Department of Electrical and Electronic Engineering at Stellenbosch University. Experimental measurements included piston and displacer motions, hot side and cold side temperatures, working space pressure, electric generator output, as well as heat rejection via a water jacket. Experimental measurements were taken prior to and subsequent to the addition of the electric generator. Indicated power was calculated as 0,659 W at a frequency of 10,99 Hz prior to the addition of the electric generator. The addition of the electric generator was unsuccessful since it was not well matched with the engine. The indicated power calculated was between 0,138 W and 0,144 W for different loads on the electric generator, while the electrical output power ranged from 1,23 mWe to 1,79 mWe. The addition of the electric generator produced non-continuous motion caused by magnetic forces instead of engine pressure variations. The major manufacturing diffculty was the attachment of magnets for the electric generator, but this was overcome with the manufacture of a special assembly jig. The theoretical simulation model was a combination of a third-order and dynamic analysis. Working space values were solved by the application of the conservation of mass, momentum and energy equations for a one-dimensional discretised model of the engine, while the motion of the piston and displacer was determined by applying the equations of motion. The majority of experimental measurements were predicted more accurately when higher heat transfer coeficients were used between the working space and wall temperatures. The theoretical simulation model was used to gain insight into the effect of input parameters on engine operation. The displacer rod diameter was shown to have implications on output power and stability, while it was shown that there is a natural tendency to deliver constant output power at a near-constant frequency over a range of piston loads for an FPSE. It was also shown that the design of an FPSE is complex and that the design of all components should be done in parallel. The control of an FPSE was seen to be both a necessity and can be used to exploit the advantages of the uncoupled nature of an FPSE.
AFRIKKANSE OPSOMMING: Die doel van hierdie studie was om 'n eksperimentele toetsbare vrye-werksuier Stirling enjin te vervaardiging, wat 'n lineêre elektriese kragopwekker insluit; om 'n teoretiese simulasie model te ontwikkel en te yk; om vervaardiging probleme te identi seer; en om die ondernemende werk te assesseer om 'n fondasie te lê vir die toekomstige ontwikkeling van 'n 3 kWe vrye-werksuier Stirling enjin wat by 'n Stirling sonskottel ingelyf kan word. 'n Herontwerpte weergawe van die Beale B-10B demonstrasie enjin was vervaardig om ontwerp probleme te bowe te kom en om die toets daarvan te vereenvoudig. Die ontwerp het gebruik gemaak van 'n elektriese kragopwekker wat by die Departement Elektriese en Elektroniese Ingenieurswese aan die Universiteit van Stellenbosch ontwerp is. Eksperimentele metings het die werksuier en verplaser bewegings ingesluit, sowel as die warm kant en koue kant temperature, die werkruimte druk, die elektriese uitset van die kragopwekker, sowel as die hitteuitruiling wat met 'n water verkoelingskringloop gepaard gaan. Eksperimentele metings was geneem voor en na die byvoeging van die elektriese kragopwekker. Kraglewering was bereken op 0,659 W teen 'n frekwensie van 10,99 Hz voordat die elektriese kragopwekker bygevoeg is. Die byvoeging van die elektriese kragopwekker was onsuksesvol omdat die nie gepas was vir die enjin nie. Die kraglewering is bereken op vlakke wat gewissel het tussen 0,138 W en 0,144 W vir die verskillende belastings op die elektriese kragopwekker, terwyl die elektriese uitset gewissel het tussen 1,23 mWe en 1,79 mWe. Die byvoeging van die elektriese kragopwekker het 'n nie-aaneenlopende beweging veroorsaak weens die magnetiese kragte wat dit beinvloed het in plaas van enjindruk variasies. Die belangrikste ontwerpuitdagings was die ontwerp van 'n werksuier en verplaser wat 'n klein toleransie passing kon handhaaf om sodoende 'n seël te verseker terwyl dit aan temperatuur variasies blootgestel was. Die grootste vervaardigingsprobleem was die aanheg van magnete vir die elektriese kragopwekker, maar dit is te bowe gekom deur 'n spesiale voeg te vervaardig. Die teoretiese simulasie model was 'n kombinasie van 'n derde-orde en 'n dinamiese analise. Werkruimte waardes was opgelos deur die toepassing van die behoud van massa, momentum en energie vergelykings vir 'n een-dimensionele gediskretiseerde model van die enjin, terwyl die beweging van die werksuier en verplaser bepaal was deur die toepassing van die bewegingvergelykings. Die meerderheid van die eksperimentele metings was meer akkuraat voorspel wanneer hoër warmteoordrag koë siënte tussen die werkruimte en muurtemperature gebruik was. Die teoretiese simulasie model was gebruik om insig in terme van die e ek van invoer veranderlikes op die enjin gedrag te toon. Daar was getoon dat die verplaserstaaf diameter implikasies het op kragoplewering en stabiliteit, terwyl die natuurlike tendens van 'n vrye-werksuier Stirling enjin gewys was om 'n konstante kraguitvoer te lewer op 'n naby-konstante frekwensie oor 'n reeks werksuier laste. Daar was ook gewys dat die ontwerp van 'n vryewerksuier Stirling enjin kompleks is en dat die ontwerp van alle komponente in parallel gedoen moet word. Die beheer van 'n vrye-werksuier Stirling enjin was gewys om beide noodsaaklik te wees, sowel as gebruik kan word om die unieke voordele van 'n vrye-werksuier Stirling enjin se ongekoppelde natuur te ontgin.