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1
Ahmed, Mustafa M. Abdalla. "Alternating-Current Thin-Film Electroluminescent Device Characterization." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-233432.
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Jádrem této disertační práce bylo studovat optické a elektrické charakteristiky tenkovrstvých elektroluminiscenčních součástek řízených střídavým proudem (ACTFEL) a zejména vliv procesu stárnutí luminiforů na jejich optické a elektrické vlastnosti. Cílem této studie měl být příspěvek ke zvýšení celkové účinnosti luminoforů, vyjádřené pomocí jasu, účinnosti a stability. Vzhledem k tomu, že současnou dominantní technologií plochých obrazovek je LCD, musí se další alternativní technologie plošných displejů porovnávat s LCD. Výhodou ACTFEL displejů proti LCD je lepší rozlišení, větší teplotní rozsah činnosti, větší čtecí úhel, či možnost čtení při mnohem vyšší intenzitě pozadí. Na druhou stranu je jejich nevýhodou vyšší energetická náročnost, problém s odpovídající barevností tří základních barev a podstatně vyšší napětí nutné pro činnost displeje. K dosažení tohoto cíle jsme provedli optická, elektrická a optoelektrická měření ACTFEL struktur a ZnS:Mn luminoforů. Navíc jsme studovali vliv dotování vrstvy pomocí KCl na chování mikrostruktury a na elektroluminiscenční vlastnosti (zejména na jas a světelnou účinnost) ZnS:Mn luminoforů. Provedli jsme i některá, ne zcela obvyklá, měření ACTFEL součástek. Vypočítali jsme i rozptylový poměr nabitých barevných center a simulovali transportní charakteristiky v ACTFEL součástkách. Studovali jsme vliv stárnutí dvou typů ZnS:Mn luminoforů (s vrstvou napařenou či získanou pomocí epitaxe atomových vrstev) monitorováním závislostí svítivost-napětí (L-V), velikost vnitřního náboje - elektrické pole luminoforu (Q-Fp) a kapacitance-napětí (C-V) ve zvolených časových intervalech v průběhu stárnutí. Provedli jsme krátkodobá i dlouhodobá měření a pokusili jsme se i o vizualizaci struktury luminoforu se subvlnovým rozlišením pomocí optického rastrovacího mikroskopu pracujícího v blízkém poli (SNOM). Na praktickém případu zeleného Zn2GeO4:Mn (2% Mn) ACTFEL displeje, pracujícího při 50 Hz, jsme také studovali stabilitu svítivosti pomocí měření závislosti svítivosti na napětí (L-V) a světelné účinnosti na napětí (eta-V). Přitom byl zhodnocen význam těchto charakteristik. Nezanedbatelnou a neoddělitelnou součástí této práce je i její pedagogický aspekt. Předložený text by mohl být využit i jako učebnice pro studenty na mé univerzitě v Lybii.
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Lamanda, Ariana Corinne. "Alternating Current Electrokinetic Manipulation and Concentration of Free Circulating DNA from Blood Samples." Thesis, The University of Arizona, 2014. http://hdl.handle.net/10150/332828.
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Molecular analysis of free circulating (fc)DNA has the potential to change the face of medicine, specifically in cancer diagnostics and in monitoring the efficacy of cancer treatments. In this study, a microfluidic device using AC electrokinetics is developed for rapid concentration and detection of fcDNA from blood. The device concentrates fcDNA using a combination of AC electrothermal flow and dielectrophoresis. The electrothermal fluid motion drives fcDNA towards the center of the electrode where dielectrophoretic trapping occurs. Once fcDNA is collected at the center, the concentration in the sample can be determined by fluorescent analysis using an intercalating dye binding to the double-stranded DNA. Effects of operating parameters are investigated to optimize the device's design. The electrokinetic device isolates high molecular weight DNA and can distinguish from low molecular weight DNA. Quantitative detection of fcDNA in physiologically relevant concentrations is demonstrated toward rapid diagnostics of cancer and monitoring of treatment efficacy.
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Ngu, Sze Song. "Design and control of a direct drive slotless permanent magnet alternating current generator for low speed Bristol cylinder wave device." Thesis, University of Glasgow, 2013. http://theses.gla.ac.uk/4746/.
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Global demand for renewable energy is at an all-time high. Renewable energy can be extracted from naturally available resources such solar, wind, tides, geothermal heat, sea waves and the others. The percentage of renewable energy in the energy resources is increasing at an ever increasing rate. While much renewable energy is large scale, it is also suitable for rural and remote areas. The challenges facing today’s renewable energy supply industry are many, especially in the wave energy field which is still underdeveloped. The number of commercialised wave energy devices is very limited and the concepts implemented for harnessing wave energy are very different between the different devices and often struggle to be effective or survive ocean-going conditions. Thus, major research is required to find new and effective methods for harnessing wave energy which are able to supply power to the grid with high conversion rate and good reliability. The proposed Bristol cylinder device, in theory, should be able to harness sea wave energy and to convert it into useful electricity, and this device is studied in detail here. This device is still new in terms of practical application in ocean conditions. It needs power electronics and effective controllers for high-efficiency power extraction and to be successfully integrated into the power grid. When the device was first investigated in the 1970s, power electronics and variable-speed brushless permanent-magnet machinery was simply not developed to the level it is today, hence the revisiting of this device several decades later. A successful Bristol cylinder wave device which can extract renewable energy may well impact on the renewable energy sector. The wave characteristics were studied and simulated using Airy Linear Wave Theory and Stoke’s Second Order Theory. The dynamic characteristics of the Bristol cylinder are investigated when interacting with waves, together with the control necessary to make it a functioning device. A lab scale wave tank suitable to test the Bristol cylinder is designed. A surface magnet permanent magnet synchronous generator (PMSG) design is considered in this research project. This generator configuration shows its suitability in producing high conversion-rate power when working in a low speed environment. The sizing exercise is performed to determine the size of the lab scale PMSG. Analytical analysis and finite element analysis is performed to study the performance of the designed PMSG. A study of the effect of the armature length with the corresponding incident wave is done. Field oriented control (FOC) is applied to control the speed of the generator. FOC is shown to be suitable for stable control of the generator speed. Simulations using MATLAB are utilized and Simulink is used to construct the model and evaluate the potential performance of the control system design. In this thesis, theoretical analyses and simulations of the generator performances are carried out for several generator topologies and sizes. The grid side converter controller technique is also simulated in MATLAB/Simulink and the performance evaluated.
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Kovchar, Jean. "Design, modeling, fabrication and characterization of a micro-device for the study of alternating flow - Application to energy harvesting and conversion." Electronic Thesis or Diss., Bourgogne Franche-Comté, 2024. http://www.theses.fr/2024UBFCD009.
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Cette thèse porte sur l'étude d'écoulements alternés au sein de canaux de dimensions milli- et sub-millimétriques. Ces travaux visent à contribuer à l'optimisation d'une machine miniature (dimensions sub-millimétriques) de récupération et de conversion d'énergie basse température (T < 200 °C) basée sur le principe du cycle de Stirling. Ceci s'inscrit dans le contexte de valorisation de la chaleur fatale encore non exploitée dans de nombreux milieux industriels. Dans les machines de type Stirling, les écoulements du fluide de travail sont alternés. Bien que ces écoulements soient assez bien connus à l’échelle macroscopique, ils le sont très peu à échelle milli et sub-millimétrique. Or une bonne compréhension de ce type d’écoulement à ces échelles est primordiale lors des phases de dimensionnement et design des machines. Afin de contribuer à la caractérisation des écoulement alternés à ces petites échelles, des canaux dont les dimensions sont proches de celles de la machine miniature ont été réalisés par des moyens technologiques de microfabrication au sein de la centrale technologique MIMENTO de l'Institut FEMTO-ST. Les canaux réalisés ont un diamètre hydraulique variant entre 200 µm et 1 mm, un rapport d'aspect compris entre 0.1 et 1 et deux longueurs de canal différentes (25 mm et 50 mm). Des canaux avec des coudes ont également été réalisés afin d'étudier leur influence sur les caractéristiques de l'écoulement. Ces canaux ont ensuite été implémentés sur le banc expérimental. Dans un premier temps, l'étude a porté sur la caractérisation des écoulements permanents, dans la gamme de Reynolds de 15 à 510, dont les résultats, en accord avec ceux issus de la littérature, ont servi de référence pour l'étude d'écoulements alternés, menée par la suite dans une gamme de nombres de Womersley allant de 0.02 à 0.67.La caractérisation des écoulements alternés a permis de déterminer que le rapport d'aspect et le diamètre hydraulique des canaux affectent significativement l'écoulement. En revanche, les travaux issus de cette thèse ont montré que l'influence de la longueur du canal ainsi que la présence de singularités (coudes) sur les caractéristiques de l'écoulement ne semblent pas être aussi déterminantes qu'attendu.Parmi les paramètres testés au cours de cette thèse, il a été montré que le rapport d'aspect et le diamètre hydraulique des canaux sont des paramètres importants à prendre en compte dans le design de micro machines de Stirling, notamment afin de ne pas impacter considérablement son efficacitéThis thesis focuses on the study of alternating flows within milli- and sub-millimeter-sized channels. The aim is to contribute to the optimization of a miniature (sub-millimeter dimensions) low-temperature (T < 200 °C) energy recovery and conversion machine based on the Stirling cycle principle. This is in line with the recovery of waste heat which is still not exploited in many industrial environments. In Stirling-type engines, the working fluid flows in alternating directions. Although these flows are fairly well understood on a macroscopic scale, very little is known about them on milli and sub-millimeter scales. However, a good understanding of this type of flow at these scales is essential for engine dimensioning and design. In order to contribute to the characterization of alternating flows at these small scales, channels with dimensions close to those of the miniature machine were produced using microfabrication technology. The channels produced have a hydraulic diameter ranging from 200 µm to 1 mm, an aspect ratio between 0.1 and 1, and two different channel lengths (25 mm and 50 mm). Channels with bends were also built to study their influence on flow characteristics. These channels were then implemented on the experimental bench. Initially, the study focused on the characterization of permanent flows, in the Reynolds range from 15 to 510, whose results, in agreement with those from the literature, served as a reference for the study of alternating flows, carried out in a second step with a Womersley number ranging from 0.02 to 0.67. The characterization of alternating flows has shown that the aspect ratio and the hydraulic diameter of the channels affect the flow significantly. On the other hand, this thesis has shown that the influence of channel length and the presence of singularities (bends) on the flow characteristics do not appear to be as decisive as expected. Consequently, among the parameters tested in this thesis, the aspect ratio and hydraulic diameter of the channels are important parameters to take into account for the design of the micro Stirling machine, especially to avoid impacting considerably its efficiency
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Hrabal, Michal. "Development of Light Emitting Electroluminescent Device by Means of Material Printing." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2019. http://www.nusl.cz/ntk/nusl-402111.
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Cílem této práce je vývoj světelného zdroje založeného na technologii tlustostěnného elektroluminiscenčního panelu napájeného střídavým napětím (ACPEL). V současné době se jedná se o jedinou technologii založenou na metodách materiálového tisku vhodnou pro přípravu velkoplošných, flexibilních a vzorovaných zdrojů světla. Důraz je v této práci kladen na představení, prozkoumání a odstranění typických problémů, které jsou spojovány s touto technologií. Tyto problémy jsou omezený odstín barvy emitovaného světla a dlouhodobá stabilita elektroluminiscenčního prvku, který je vystaven vlivům prostředí. Rešeršní část dizertační práce je zaměřena na představení a identifikaci depozičních technik, vhodných pro reprodukovatelnou přípravu ACPEL panelů. Dalším cílem je identifikace fyzikálních parametrů, vhodných pro charakterizaci velkoplošných zdrojů světla. Praktickým cílem práce je nalezení vhodné metodologie pro popis a charakterizaci panelů, jakožto plošných světelných zdrojů. Fotometrická veličina jas L a spotřeba elektrické energie P byly vyhodnoceny jako vhodné parametry, určující aplikaci ACPEL panelů. Na modrém panelu bylo dosaženo maximální hodnoty jasu L = 133 cd•m2 při napětí Upp = 500 V a frekvenci f = 1000 Hz. Hodnoty spotřeby elektrické energie, vztažené na jednotkovou plochu panelů zkoumaných v této práci, jsou (7±3) mW. Tyto dosažené hodnoty dělají ze světelných zdrojů založených na ACPEL technologii zajímavé kandidáty pro různé aplikace. Vlivu rostoucí amplitudy a frekvence budícího napětí na dlouhodobou stabilitu panelů je důležitým cílem této práce. Pro popis stability byly zavedeny parametry L50 and L75. Bylo zjištěno, že rostoucí frekvence budícího napětí zkracuje životnost panelů. Laminovaný panel napájený napětím s přibližně trojnásobně vyšší frekvencí vykazoval přibližně třetinové hodnoty parametrů L50 a L75. Nejvyšších hodnot stabilitních parametrů dosahoval panel enkapsulován mezi skleněné pláty – přibližně sedminásobnou hodnotu oproti laminovanému panelu s trojnásobnou frekvencí. Optimální stability panelů lze dosáhnout při nastavení frekvence v rozmezí 400–800 Hz a zapouzdřením mezi sklo. Úzká paleta odstínů barev emitovaného světla je jeden z typických problémů, který dále zkoumán v dizertační práci. Tato práce zkoumá nadějnou metodu, přídavek vhodného materiálu pro konverzi barvy (CCM). Nový derivát diketopyrrolopyrrolu (DPP), absorbující v modré oblasti, byl přidán k modrému fosforu a byl pozorován sedminásobný narůst hodnot absolutního spektrálního ozáření v oblasti vlnových délek odpovídajících maximální emisi CCM materiálu. Jednoduchost přípravy vyvinutých zdrojů světla spolu s velmi nízkou spotřebou a vysokou dobou života dělají z ACPEL panelů zajímavé kandidáty pro podsvícení prvků například v automobilovém průmyslu, pro dekorativní osvětlení, pro „branding“ – zvýraznění reklamních značek.
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Denmark, Daniel Jonwal. "Photopolymerization Synthesis of Magnetic Nanoparticle Embedded Nanogels for Targeted Biotherapeutic Delivery." Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/6827.
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Conventional therapeutic techniques treat the patient by delivering a biotherapeutic to the entire body rather than the target tissue. In the case of chemotherapy, the biotherapeutic is a drug that kills healthy and diseased cells indiscriminately which can lead to undesirable side effects. With targeted delivery, biotherapeutics can be delivered directly to the diseased tissue significantly reducing exposure to otherwise healthy tissue. Typical composite delivery devices are minimally composed of a stimuli responsive polymer, such as poly(N-isopropylacrylamide), allowing for triggered release when heated beyond approximately 32 °C, and magnetic nanoparticles which enable targeting as well as provide a mechanism for stimulus upon alternating magnetic field heating. Although more traditional methods, such as emulsion polymerization, have been used to realize these composite devices, the synthesis is problematic. Poisonous surfactants that are necessary to prevent agglomeration must be removed from the finished polymer, increasing the time and cost of the process. This study seeks to further explore non-toxic, biocompatible, non-residual, photochemical methods of creating stimuli responsive nanogels to advance the targeted biotherapeutic delivery field. Ultraviolet photopolymerization promises to be more efficient, while ensuring safety by using only biocompatible substances. The reactants selected for nanogel fabrication were N-isopropylacrylamide as monomer, methylene bisacrylamide as cross-linker, and Irgacure 2959 as ultraviolet photo-initiator. The superparamagnetic nanoparticles for encapsulation were approximately 10 nm in diameter and composed of magnetite to enable remote delivery and enhanced triggered release properties. Early investigations into the interactions of the polymer and nanoparticles employ a pioneering experimental setup, which allows for coincident turbidimetry and alternating magnetic field heating of an aqueous solution containing both materials. Herein, a low-cost, scalable, and rapid, custom ultraviolet photo-reactor with in-situ, spectroscopic monitoring system is used to observe the synthesis as the sample undergoes photopolymerization. This method also allows in-situ encapsulation of the magnetic nanoparticles simplifying the process. Size characterization of the resulting nanogels was performed by Transmission Electron Microscopy revealing size-tunable nanogel spheres between 50 and 800 nm by varying the ratio and concentration of the reactants. Nano-Tracking Analysis indicates that the nanogels exhibit minimal agglomeration as well as provides a temperature-dependent particle size distribution. Optical characterization utilized Fourier Transform Infrared and Ultraviolet Spectroscopy to confirm successful polymerization. When samples of the nanogels encapsulating magnetic nanoparticles were subjected to an alternating magnetic field a temperature increase was observed indicating that triggered release is possible. Furthermore, a model, based on linear response theory that innovatively utilizes size distribution data, is presented to explain alternating magnetic field heating results. The results presented here will advance targeted biotherapeutic delivery and have a wide range of applications in medical sciences like oncology, gene delivery, cardiology and endocrinology.
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Jakupovic, Edin. "Alternative Information Gathering on Mobile Devices." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-210712.
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Searching and gathering information about specific topics is a time wasting, but vital practise. With the continuous growth and surpassing of desktop devices, the mobile market is becoming a more important area to consider. Due to the portability of mobile devices, certain tasks are more difficult to perform, compared to on a desktop device. Searching for information online is generally slower on mobile devices than on desktop devices, even though the majority of searches are performed on mobile devices. The largest challenges with searching for information online using mobile devices, are the smaller screen sizes, and the time spent jumping between sources and search results in a browser. These challenges could be solved by using an application that focuses on the relevancy of search results, summarizes the content of them, and presents them on a single screen. The aim of this study was to find an alternative data gathering method with a faster and simpler searching experience. This data gathering method was able to quickly find and gather data requested through a search term by a user. The data was then analyzed and presented to the user in a summarized form, to eliminate the need to visit the source of the content. A survey was performed by having a smaller target group of users answer a questionnaire. The results showed that the method was quick, results were often relevant, and the summaries reduced the need to visit the source page. But while the method had potential for future development, it is hindered by ethical issues related to the use of web scrapers.Sökning och insamling av information om specifika ämnen är en tidskrävande, men nödvändig praxis. Med den kontinuerliga tillväxten som gått förbi stationära enheters andel, blir mobilmarknaden ett viktigt område att överväga. Med tanke på rörligheten av bärbara enheter, så blir vissa uppgifter svårare att utföra, jämfört med på stationära enheter. Att söka efter information på Internet är generellt långsammare på mobila enheter än på stationära. De största utmaningarna med att söka efter information på Internet med mobila enheter, är de mindre skärmstorlekarna, och tiden spenderad på att ta sig mellan källor och sökresultat i en webbläsare. Dessa utmaningar kan lösas genom att använda en applikation som fokuserar på relevanta sökresultat och sammanfattar innehållet av dem, samt presenterar dem på en enda vy. Syftet med denna studie är att hitta en alternativ datainsamlingsmetod för attskapa en snabbare och enklare sökupplevelse. Denna datainsamlingsmetod kommer snabbt att kunna hitta och samla in data som begärts via en sökterm av en användare. Därefter analyseras och presenteras data för användaren i en sammanfattad form för att eliminera behovet av att besöka innehållets källa. En undersökning utfördes genom att en mindre målgrupp av användare svarade på ett formulär av frågor. Resultaten visade att metoden var snabb, resultaten var ofta relevanta och sammanfattningarna minskade behovet av att besöka källsidan. Men medan metoden hade potential för framtida utveckling, hindras det av de etiska problemen som associeras med användningen av web scrapers.
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Kim, Yong Hyun. "Alternative Electrodes for Organic Optoelectronic Devices." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-113279.
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This work demonstrates an approach to develop low-cost, semi-transparent, long-term stable, and efficient organic photovoltaic (OPV) cells and organic light-emitting diodes (OLEDs) using various alternative electrodes such as conductive polymers, doped ZnO, and carbon nanotubes. Such electrodes are regarded as good candidates to replace the conventional indium tin oxide (ITO) electrode, which is expensive, brittle, and limiting the manufacturing of low-cost, flexible organic devices. First, we report long-term stable, efficient ITO-free OPV cells and transparent OLEDs based on poly(3,4-ethylene-dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) electrodes by using a solvent post-treatment or a structure optimization. In addition, a high performance internal light out-coupling system for white OLEDs based on PEDOT:PSS-coated metal oxide nanostructures is developed. Next, we demonstrate highly efficient ITO-free OPV cells and OLEDs with optimized ZnO electrodes doped with alternative non-metallic elements. The organic devices based on the optimized ZnO electrodes show significantly improved efficiencies compared to devices with standard ITO. Finally, we report semi-transparent OPV cells with free-standing carbon nanotube sheets as transparent top electrodes. The resulting OPV cells exhibit very low leakage currents with good long-term stability. In addition, the combination of various kinds of bottom and top electrodes for semi-transparent and ITO-free OPV cells is investigated. These results demonstrate that alternative electrodes-based OPV cells and OLEDs have a promising future for practical applications in efficient, low-cost, flexible and semi-transparent device manufacturingDie vorliegende Arbeit demonstriert einen Ansatz zur Verwirklichung von kostengünstigen, semi-transparenten, langzeitstabilen und effizienten Organischen Photovoltaik Zellen (OPV) und Organischen Leuchtdioden (OLEDs) durch die Nutzung innovativer Elektrodensysteme. Dazu werden leitfähige Polymere, dotiertes ZnO und Kohlenstoff-Nanoröhrchen eingesetzt. Diese alternativen Elektrodensysteme sind vielversprechende Kandidaten, um das konventionell genutzte Indium-Zinn-Oxid (ITO), welches aufgrund seines hohen Preises und spröden Materialverhaltens einen stark begrenz Faktor bei der Herstellung von kostengünstigen, flexiblen, organischen Bauelementen darstellt, zu ersetzten. Zunächst werden langzeitstabile, effiziente, ITO-freie Solarzellen und transparente OLEDs auf der Basis von Poly(3,4-ethylene-dioxythiophene):Poly(styrenesulfonate) (PEDOT:PSS) Elektroden beschrieben, welche mit Hilfe einer Lösungsmittel-Nachprozessierung und einer Optimierung der Bauelementstruktur hergestellt wurden. Zusätzlich wurde ein leistungsfähiges, internes Lichtauskopplungs-System für weiße OLEDs, basierend auf PEDOT:PSS-beschichteten Metalloxid-Nanostrukturen, entwickelt. Weiterhin werden hoch effiziente, ITO-freie OPV Zellen und OLEDs vorgestellt, bei denen mit verschiedenen nicht-metallischen Elementen dotierte ZnO Elektroden zur Anwendung kamen. Die optimierten ZnO Elektroden bieten im Vergleich zu unserem Laborstandard ITO eine signifikant verbesserte Effizienz. Abschließend werden semi-transparente OPV Zellen mit freistehenden Kohlenstoff-Nanoröhrchen als transparente Top-Elektrode vorgestellt. Die daraus resultierenden Zellen zeigen sehr niedrige Leckströme und eine zufriedenstellende Stabilität. In diesem Zusammenhang wurde auch verschiedene Kombinationen von Elektrodenmaterialen als Top- und Bottom-Elektrode für semi-transparente, ITO-freie OPV Zellen untersucht. Zusammengefasst bestätigen die Resultate, dass OPV und OLEDs basierend auf alternativen Elektroden vielversprechende Eigenschaften für die praktische Anwendung in der Herstellung von effizienten, kostengünstigen, flexiblen und semi-transparenten Bauelement besitzen
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Wang, Xian. "Enabling low cost test and tuning of difficult-to-measure device specifications: application to DC-DC converters and high speed devices." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53521.
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Low-cost test and tuning methods for difficult-to-measure specifications are presented in this research from the following perspectives: 1)"Safe" test and self-tuning for power converters: To avoid the risk of device under test (DUT) damage during conventional load/line regulation measurement on power converter, a "safe" alternate test structure is developed where the power converter (boost/buck converter) is placed in a different mode of operation during alternative test (light switching load) as opposed to standard test (heavy switching load) to prevent damage to the DUT during manufacturing test. Based on the alternative test structure, self-tuning methods for both boost and buck converters are also developed in this thesis. In addition, to make these test structures suitable for on-chip built-in self-test (BIST) application, a special sensing circuit has been designed and implemented. Stability analysis filters and appropriate models are also implemented to predict the DUT’s electrical stability condition during test and to further predict the values of tuning knobs needed for the tuning process. 2) High bandwidth RF signal generation: Up-convertion has been widely used in high frequency RF signal generation but mixer nonlinearity results in signal distortion that is difficult to eliminate with such methods. To address this problem, a framework for low-cost high-fidelity wideband RF signal generation is developed in this thesis. Depending on the band-limited target waveform, the input data for two interleaved DACs (digital-to-analog converters) system is optimized by a matrix-model-based algorithm in such a way that it minimizes the distortion between one of its image replicas in the frequency domain and the target RF waveform within a specified signal bandwidth. The approach is used to demonstrate how interferers with specified frequency characteristics can be synthesized at low cost for interference testing of RF communications systems. The frameworks presented in this thesis have a significant impact in enabling low-cost test and tuning of difficult-to-measure device specifications for power converter and high-speed devices.
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Fröbel, Markus. "Novel Concepts For Alternating Current Operated Organic Light-Emitting Devices." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-221652.
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Inorganic alternating current electroluminescent devices (AC-ELs) are known for their ruggedness and extreme long-term reliability, which is why they can often been found in industrial and medical equipment as well as in applications in the military sector. In contrast to the inorganic phosphors used in AC-ELs, organic materials offer a number of advantages, in particular a significantly higher efficiency, easier processibility, and a wide selection of emitter materials spanning the entire visible spectrum. Several efforts towards alternating current driven organic light-emitting devices have recently been made, however, important operating mechanism are still not well understood. In the first part of this theses, alternating current driven, capacitively coupled, pin-based organic light-emitting devices are investigated with respect to the influence of the thickness of the insulating layer and the intrinsic organic layer on the driving voltage. A three-capacitor model is employed to predict the basic behavior of the devices and good agreement with the experimental values is found. The proposed charge regeneration mechanism based on Zener tunneling is studied in terms of field strength across the intrinsic organic layers. A remarkable consistency between the measured field strength at the onset point of light emission (3–3.1 MV/cm) and the theoretically predicted breakdown field strength of around 3 MV/cm is obtained. The latter value represents the field required for Zener tunneling in wide band gap organic materials according to Fowler-Nordheim theory. In a second step, asymmetric driving of capacitively coupled OLEDs is investigated. It is found that different voltages and/or pulse lengths for positive and negative half-cycle lead to significant improvements in terms of brightness and device efficiency.
Part two of this work demonstrates a device concept for highly efficient organic light-emitting devices whose emission color can be easily adjusted from, e.g., deep-blue through cold-white and warm-white to saturated yellow. The presented approach exploits the different polarities of the positive and negative half-cycles of an alternating current driving signal to independently address a fluorescent blue emission unit and a phosphorescent yellow emission unit vertically stacked on top of each other. The electrode design is optimized for simple fabrication and driving and allows for two-terminal operation by a single source. The presented approach for color-tunable OLEDs is versatile in terms of emitter combinations and meets application requirements by providing a high device efficiency of 36.2 lm/W, a color rendering index of 82 at application relevant brightness levels of 1000 cd/m², and warm-white emission color coordinates.
The final part demonstrates an approach for full-color OLED pixels that are fabricated by vertical stacking of a red-, green-, and blue-emitting unit. Each unit can be addressed separately which allows to efficiently generate every color that is a superposition of spectra of the individual emission units. The device is built in a top-emission geometrywhich is highly desirable for display fabrication as the pixel can be directly deposited onto the back-plane electronics. Furthermore, the presented device design requires only three independently addressable electrodes which simplifies fabrication and electrical driving.
The electrical performance of each individual unit is on par with standard pin single emission unit OLEDs, showing very low leakage currents and achieving high brightness levels at moderate voltages of around 3–4 V.
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Kim, Na-Hyun. "Introducing Deache mouse : An alternative computer mouse design for people with fine motor skill impairments." Thesis, Umeå universitet, Institutionen för informatik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-160907.
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Taylor, Robert A. "Comprehensive optimization for thermoelectric refrigeration devices." Diss., Columbia, Mo. : University of Missouri-Columbia, 2005. http://hdl.handle.net/10355/4247.
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Thesis (M.S.)--University of Missouri-Columbia, 2005.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (December 20, 2006) Includes bibliographical references.
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Fathi, S. Hamid. "The performance of brushless DC drives with alternative torque control methods." Thesis, University of Newcastle Upon Tyne, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315569.
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Giebelhaus, Carmen R. "The mechanical third ear device : a student teaching supervision alternative /." The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu1341502264.
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Elsass, Peyras Véronique. "Apprendre dans le supérieur : le point de vue des étudiants en soins infirmiers. Des stratégies d’adaptation face à l’acte d’apprendre à la conscientisation du processus de construction identitaire." Electronic Thesis or Diss., Université de Lorraine, 2024. http://www.theses.fr/2024LORR0079.
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Si le passage dans l’enseignement supérieur nécessite un temps d’adaptation (Paivandi, 2015), force est de constater que les étudiants en soins infirmiers sont particulièrement exposés au stress pendant la formation, contrairement à d'autres filières (Narchi-Séoud, 2011) et que cette vulnérabilité se prolonge au-delà de la phase de découverte des études (Lamaurt el al, 2011 ; Morenon, 2017 ; Narchi-Séoud, 2021). Très attirés par le caractère court et professionnalisant de la formation infirmière, ainsi que par les valeurs humanistes que véhicule le métier, les étudiants se retrouvent en proie à de nombreuses tensions dès leur admission :- Ils sont souvent très déconcertés par le haut niveau d'exigence attendu qui les contraint à des évaluations nombreuses et polymorphes, sur les trois ans de la formation,- Leur volonté d'être opérationnels dès l'obtention du diplôme influence leurs représentations sur les connaissances à acquérir et les place dans une perspective utilitariste des savoirs,- La stricte application sur les référentiels de compétences (Campia, 2016) ne permet pas de garantir l'authenticité et la dimension humaine attendues par les étudiants, ni leur "formativité" alors que le développement personnel, qui plus est dans une formation à forte dimension axiologique, ne peut pas être dissocié de la construction professionnelle. (Honoré, 2019).- Le nombre élevé des pratiques évaluatives place l'évaluation au centre de leurs préoccupations, au risque de déplacer l'objectif d'intégration des connaissances vers le seul objectif de capitalisation des crédits (Paivandi et Coulon, 2008). De plus, la question se pose de savoir si un dispositif hautement évaluatif est susceptible de permettre une intégration des savoirs efficaces et à l'émergence d'une identité professionnelle conforme aux attentes institutionnelles, sachant que des échecs répétés aux examens entrainent une inefficacité des apprentissages et un sentiment d'échec (Younès, 2023).Ainsi, cette thèse a pour objectif de définir dans quelle mesure les perspectives d'apprentissage des étudiants infirmiers sont constitutives de perceptions différenciées du dispositif de formation à l'aune de leurs expériences individuelles (trajectoires, héritage scolaire...) et permettent de traduire leur capacité à s'émanciper de la dimension strictement normative du dispositif évaluatif. Partant du principe qu'"aucune perspective, quantitative ou qualitative, ne [permet] à elle seule de représenter adéquatement la réalité " (Hunt et Lavoie, 2011, p.29), une enquête séquentielle mixte a été menée auprès d’une promotion d’étudiants infirmiers en 3ème année : Un questionnaire visant à décrire le public cible et à identifier les différents phénomènes sociologiques liés à la vie étudiante, suivi par une série d'entretiens semi-directifs, dans une visée compréhensive et explicative (Paillé et Mucchielli, 2021). Les résultats de l'enquête ont permis de constater que l'efficience tient une place centrale dans l'approche étudiante, d'identifier une catégorie d'apprenants peu pris en compte dans les grandes enquêtes nationales de l'enseignement supérieur, de démontrer la place centrale du stage dans le développement de l'identité professionnelle, et de repérer quatre typologies d'apprenants infirmiers, émergeant de la confluence entre leur parcours initial et leurs motivations. Ils présentent des similitudes avec le modèle des perspectives d’apprentissage élaboré par Saeed Paivandi mais notre public révèle certaines particularités que nous avons catégorisées et nuancées. A l'issue de cette enquête, nous proposons diverses perspectives pour faire converger les besoins des apprenants avec les attentes du curriculum, autant de prémisses d'une réingénierie de la formation en sciences infirmières qui est en coursWhile transition to higher education requires time to adapt (Paivandi, 2015), it is clear that nursing students are particularly exposed to stress during training, unlike other sectors (Narchi-Séoud, 2011) and that this vulnerability extends beyond the discovery phase of the studies (Lamaurt el al, 2011; Morenon, 2017; Narchi-Séoud, 2021). Very attracted by the short and professionalizing nature of nursing education, as well as the humanistic values that the profession conveys, students find themselves in the grip of many tensions upon admission:- They are often very disconcerted by the high level of requirement expected, which forces them to make numerous and polymorphic evaluations over the three years of training,- Their willingness to be operational from graduation influences their representations on the knowledge to be acquired and places them in a utilitarian perspective of knowledge,- The strict application on competency frameworks (Campia, 2016) does not guarantee the authenticity and human dimension expected by students, nor their "formativity" while personal development, what is more in a formation with a strong axiological dimension, cannot be dissociated from professional construction. (Honoré, 2019). - The high number of evaluation practices places evaluation at the centre of their concerns, at the risk of shifting the objective of knowledge integration towards the sole objective of credit capitalization (Paivandi and Coulon, 2008). In addition, the question arises whether the highly evaluative system is likely to allow an effective integration of knowledge and the emergence of a professional identity in line with institutional expectations, knowing that repeated failures in exams lead to ineffective learning and a sense of failure (Younès, 2023).Thus, this thesis aims to define to what extent the learning perspectives of nursing students are constitutive of differentiated perceptions of the training system in terms of their individual experiences (trajectories, school heritage...) and make it possible to translate their ability to emancipate themselves from the strictly normative dimension of the evaluation system. Based on the principle that "no single quantitative or qualitative perspective adequately represents reality" (Hunt and Lavoie, 2011, p. 29), a mixed sequential survey was conducted among a cohort of nursing students in their 3rd year: A questionnaire to describe the target audience and identify the different sociological phenomena related to student life, followed by a series of semi-structured interviews, with a comprehensive and explanatory aim (Paillé and Mucchielli, 2021).The results of the survey showed that efficiency plays a central role in the student approach, to identify a category of learners little taken into account in the major national higher education surveys, to demonstrate the central place of the internship in the development of professional identity, and to identify four typologies of nursing learners, emerging from the confluence between their initial path and their motivations. They have similarities with the model of learning perspectives developed by Saeed Paivandi but our audience reveals some peculiarities that we have categorized and nuanced. At the end of this survey, we propose various perspectives to converge the needs of learners with the expectations of the curriculum, so many premises of a reengineering of nursing training that is underway
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Chaichimansour, Mohammad. "Electro-optical characterization of alternating-current thin-film electroluminescence (ACTFEL) devices." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/15502.
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Alkelin, Viktor, and Casper Christiansen. "Alternative Input Devices for Steer-by-Wire Systems." Thesis, Linköpings universitet, Fordonssystem, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-166294.
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With the recent push towards autonomous cars, a traditional steering wheel with its mechanical connection between the road and driver may soon be unnecessary. To facilitate interior design and lower production costs whilst still maintaining a manual alternative for maneuvering, an alternative steering input device relying on Steer-by-Wire technology is investigated. In order to finish the investigation and development of the steering device within the time-span of a master thesis, the limitation to only investigate the design of a hand wheel was established. The finished alternative steering device utilises an optical encoder for position measurement and a brushless direct current (DC) motor with a planetary gearbox for force feedback. Open-loop speed control proved to be insufficient with the available hardware. Instead, an approach of two PD-controllers regulating the angular error between the steering rack and the steering device was implemented successfully. Initially, mathematical models of the system components were derived and implemented in Mathworks Simulink. The transition from models to test rig implementation proved to be difficult due to unknown parameters in the hardware components such as embedded controllers in the steering gear and the internal works of the sensor emulator used to control the steering gear. By modifying parameters in accordance with system identification measurements performed on the test rig, the models could be validated. At the end of the project, a Volvo S60 was made available and the steering device was tested with real world driving. It was discovered that controllers tuned only for good reference following in the test rig did not translate to good driveability as the controller allowed for overly aggressive maneuvers. Following some in vehicle tuning, the proposed solution performed well during testing with surprisingly high drive-ability. For future iterations of similar hand wheel design projects, a user study was performed with regards to user experience, hand wheel size and perceived driveability.
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Marks, Lori J., and M. L. McMurray. "Augmentative and Alternative Communication: A Continuum of Devices." Digital Commons @ East Tennessee State University, 2003. https://dc.etsu.edu/etsu-works/3551.
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Humeniuk, D. V. "Device for determining parameters of a solar cell model." Thesis, Київський національний університет технологій та дизайну, 2019. https://er.knutd.edu.ua/handle/123456789/13816.
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Jobst, Christoph. "Alternative Steuerungen für das VR-Labor." Bachelor's thesis, Universitätsbibliothek Leipzig, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-64155.
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Für das Virtual Reality-Labor des Instituts für Wirtschaftsinformatik der Universität Leipzig sollen Alternativen zu den bestehenden Steuerungsmöglichkeiten gefunden, an die Anlage angeschlossen und evaluiert werden. Es werden Vorgehensweisen dargelegt, die den Anschluss neuer Geräte ermöglichen sowie deren Anwendung am Beispiel der Nintendo Wii-Remote gezeigt.
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Tvingstedt, Kristofer. "Light Trapping and Alternative Electrodes for Organic Photovoltaic Devices." Doctoral thesis, Linköpings universitet, Biomolekylär och Organisk Elektronik, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-17229.
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Organic materials, such as conjugated polymers, have emerged as a promising alternative for the production of inexpensive and flexible photovoltaic cells. As conjugated polymers are soluble, liquid based printing techniques enable production on large scale to a price much lower than that for inorganic based solar cells. Present day state of the art conjugated polymer photovoltaic cells are comprised by blends of a semiconducting polymer and a soluble derivative of fullerene molecules. Such bulk heterojunction solar cells now show power conversion efficiencies of up to 4-6%. The quantum efficiency of thin film organic solar cells is however still limited by several processes, of which the most prominent limitations are the comparatively low mobility and the high level of charge recombination. Hence organic cells do not yet perform as well as their more expensive inorganic counterparts. In order to overcome this present drawback of conjugated polymer photovoltaics, efforts are continuously devoted to developing materials or devices with increased absorption or with better charge carrier transporting properties. The latter can be facilitated by increasing the mobility of the pure material or by introducing beneficial morphology to prevent carrier recombination. Minimizing the active layer film thickness is an alternative route to collect more of the generated free charge carriers. However, a minimum film thickness is always required for sufficient photon absorption. A further limitation for low cost large scale production has been the dependence on expensive transparent electrodes such as indium tin oxide. The development of cheaper electrodes compatible with fast processing is therefore of high importance. The primary aim of this work has been to increase the absorption in solar cells made from thin films of organic materials. Device construction, deploying new geometries, and evaluation of different methods to provide for light trapping and photon recycling have been strived for. Different routes to construct and incorporate light trapping structures that enable higher photon absorption in a thinner film are presented. By recycling the reflected photons and enhancing the optical path length within a thinner cell, the absorption rate, as well as the collection of more charge carriers, is provided for. Attempts have been performed by utilizing a range of different structures with feature sizes ranging from nanometers up to centimeters. Surface plasmons, Lambertian scatterers, micro lenses, tandem cells as well as larger folded cell structures have been evaluated. Naturally, some of these methods have turned out to be more successful than others. From this work it can nevertheless be concluded that proper light trapping, in thin films of organic materials for photovoltaic energy conversion, is a technique capable of improving the cell performance. In addition to the study of light trapping, two new alternative electrodes for polymer photovoltaic devices are suggested and evaluated.
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Osorio, Andres F. "Computational analysis of alternative aortic bypass for left ventricle assistant device (LVAD)." Honors in the Major Thesis, University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/1122.
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This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucf.edu/Systems/DigitalInitiatives/DigitalCollections/InternetDistributionConsentAgreementForm.pdf You may also contact the project coordinator, Kerri Bottorff, at kerri.bottorff@ucf.edu for more information.Bachelors
Engineering and Computer Science
Mechanical Engineering
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Otero, Barros Sara. "Enhancement of the light outcoupling of alternating current laterally emitting thin film electroluminescent devices." Thesis, Nottingham Trent University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314336.
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Kerber, Andreas. "Methodology for electrical characterization of MOS devices with alternative gate dielectrics." Phd thesis, [S.l. : s.n.], 2004. http://elib.tu-darmstadt.de/diss/000404.
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Baynes, Timothy Malcolm Physics Faculty of Science UNSW. "Analysis of the demagnetisation process and possible alternative magnetic treatments for naval vessels." Awarded by:University of New South Wales. School of Physics, 2002. http://handle.unsw.edu.au/1959.4/20479.
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Naval submarines and surface ships are regularly subjected to a treatment called "deperming" that seeks to design the vessel???s permanent magnetisation for optimal magnetic camouflage. A scaled model of a magnetic treatment facility (MTF) has been established as a valid system to simulate deperming and used to investigate various aspects of the deperm process including: magnetic anisotropy and demagnetising fields as factors in the physical modelling of magnetism in whole vessels; a comparison of current and alternative deperm procedures; the application of theoretical models of bulk magnetisation to calculate deperm outcomes in the physical model and in actual vessels. A "laboratory MTF" was constructed to imitate the applied field geometry at a naval MTF. The system was calibrated and it was determined that the laboratory MTF could make magnetic measurements on a CU200T-G steel bar sample with an equivalent accuracy (error = ??5%) to that of standard magnetometric equipment. Experiments were conducted with emphasis on a holistic approach to modelling the deperm process and describing magnetisation changes in whole objects. The importance of the magnetic anisotropic changes to steel with cold rolling was confirmed. In CU200T-G steel sheet the initial susceptibility (ci) was found to increase by a factor of 3 ??0.1 in the rolling direction, from a value of ~ 110 in the un-rolled steel sheet (thickness dependent). ci in the rolled sheet transverse to the rolling direction was decreased by a factor of 0.94 ??0.09 to ci in the un-rolled sheet steel. Previous studies on hull steel have neglected to account for this transformation through cold work. The demonstration on mild steel here is expected to have an analogy in the final state of the hull sheet steel as it resides in a submarine pressure hull. Future studies either on hull material or on modelling whole vessels should include the same or similar magnetic anisotropic properties in the steel(s) under investigation. Hollow circular tubes made from CA2S-E and CU200T-G steel sheet were selected as models for vessels. It was shown that these steel tubes were a good choice in this regard: minimising the complexity of the experiment whilst maintaining the validity of a deperm simulation. During a deperm there was an excellent qualitative likeness in the permanent longitudinal magnetisation (PLM) for the steel tubes to PLM in both a submarine and a surface vessel. Permanent vertical magnetisation (PVM) deperm results from the tubes displayed a close qualitative match with PVM in a submarine but not in a surface vessel. A theoretical treatment for demagnetisation factors (Nd) in hollow ellipsoids was used in conjunction with a geometrical approximation to calculate Nd for finite hollow objects of revolution. Subsequent theoretical calculations correlated well with experimental results for measured effective ci (ceff) in hollow circular CU200T-G steel tubes of various lengths and aspect ratios. Using an estimate of 100 as ci for submarine hull steel, the same analysis produces Nd for the axial and transaxial directions in a submarine equal to 5.97??10-3 and 0.0142 respectively. Three items for potential improvement were identified in the current deperm protocol used on naval vessels (Flash-D): redundancy in the protocol; the duration of the deperm and a theoretical basis for predicting the final magnetisation or changes in magnetisation during a deperm. Simulations of a novel "anhysteretic deperm" method, designed to combat these issues, compared favourably to the Flash-D protocol. The standard deviation (s) of the final PVM from 30 Flash-D deperms on steel tubes was 206 A/m; for the final PVM from 30 anhysteretic deperms of the same duration, this was 60 A/m. The s for the final PLM for Flash-D and anhysteretic deperms of the same duration were 416 A/m and 670 A/m respectively. The conclusion is that adopting the anhysteretic deperm on actual vessels would improve the reliability of the PVM outcome. Though the procedure would demand the same duration as Flash-D, there is the advantage of saving time by not having to repeat deperms to obtain the desired result. Additionally the anhysteretic deperm is considerably more amenable to theoretical analysis. A modified version of Langevin???s equation was used to predict the final PLM and PVM results for anhysteretic deperms and to provide a useful analysis of the anhysteretic processes in the Flash-D procedure. Using a Preisach analysis of hysteresis, a mathematical description of bulk magnetic changes that occur to a specific object, within a deperm, has been developed. Theoretical calculations of PLM in a steel tube during and after both types of deperm are in excellent agreement with experimental data. The same theoretical approach was also used to retrospectively model PLM results from previous Flash-D deperms on a submarine with equal success. With this analysis it is proposed that anhysteretic deperm outcomes could be predicted a priori. The influence of magnetic cargo on hull magnetisation was demonstrated to be of significance during and after deperming. "Sympathetic deperming" occurs where a magnetic source is located close to the hull during a deperm. It was found that a vessel or model vessel hull could still be demagnetised even when they contain magnetic cargo that would normally resist the direct application of the same magnetic fields. This was explained using the principles of demagnetising fields and anhysteretic magnetisation. A possible explanation was provided for a PVM measurement anomaly common to the model and vessel deperm results. From measurement, alternating longitudinal applied fields apparently induce corresponding changes in the PVM. This effect could be explained by the depermed object being offset longitudinally from the position expected by the measurement system. This offset could be estimated using an analysis of the changes to PLM and PVM after a longitudinal applied field. The offset displacements calculated for the vessels were too small to be verified experimentally (> 0.1m), but the predicted offset for the steel tubes coincided with the limit of precision for their placement in the laboratory MTF = 0.5mm The aim of this work was to look at the deperm process with reference to a system that demonstrated qualitative similarities to deperms on actual vessels. The laboratory MTF is a unique facility, permitting a useful practical analysis of deperming based on sound magnetostatic measurements The experimental and theoretical results gained here have direct application to future deperms on naval vessels with particular reference to submarines.
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Lee, Byoung Hun. "Technology development and process integration of alternative gate dielectric material : hafnium oxide /." Full text (PDF) from UMI/Dissertation Abstracts International, 2000. http://wwwlib.umi.com/cr/utexas/fullcit?p3004316.
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Vawter, Jared M. "Alternative Pointing Devices: Design and Evaluation of a System Supporting Multiple Users." Thesis, University of Ottawa (Canada), 2010. http://hdl.handle.net/10393/28783.
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This thesis evaluates alternative pointing devices for interacting with a video display. Two approaches are evaluated as potential solutions to the direct mapping problem: homography estimation, and nonlinear point-to-point mapping. These solutions use an external camera to capture the location of the laser pointer and construct a mapping between pixels of the image plane and pixels of the video display to determine where a user is pointing. Similarly, two approaches are evaluated as potential solutions to the indirect mapping problem: a variation of Tsai's extrinsic calibration algorithm, and the Nintendo Wii pointing device. These solutions, by contrast, determine where a user is pointing based on the relative position of feature points on the image plane.
To support concurrent users, techniques for differentiating among the users are evaluated. For the direct mapping solutions, two novel approaches are presented: off-the-shelf shape-based laser pointers, and custom shape-based laser pointers. In these approaches, each user is assumed to hold a laser pointer with a unique geometry. Differentiating among the users then becomes the challenge of identifying which shapes are cast on the display at a given instant. Through both simulation and trials on real image data, it is shown that custom shape-based laser pointers provide a superior solution. For indirect mapping class of solutions, a simple yet effective approach based on unique identifiers is pursued for supporting an arbitrary number of concurrent users.
For a fixed size display, results show the static accuracy of the direct mapping solutions to be within 0.317% of the distance along the display diagonal and are independent of the user's location relative to the display surface. For the indirect mapping solutions, the change in static accuracy is measured as a function of the user's location. Results show the static accuracy decreases as the angle between the pointing device and the display normal increases. For angles beyond 300, estimates using the variant of Tsai's extrinsic algorithm become unreliable; for the Nintendo Wii, estimates become unreliable beyond 50 °. The Nintendo Wii is found to have a maximum operating range of approximately 4 m from the display - irrespective of the display size. For the variant of Tsai's extrinsic algorithm, the maximum operating range could not be established; however, accurate estimates were recorded consistently beyond a distance of three times the display diagonal.
Each approach is shown to have negligible jitter and drift. The Nintendo Wii, homography, and nonlinear mapping solutions are found to have 100% reliability for static and dynamic pointing. The reliability is also found to be independent of the speed of the pointing device - up to the maximum speed that could be generated by hand. The trajectory of motion was chosen at random. For the variant of Tsai's extrinsic algorithm, the reliability is found to decrease modestly as the speed of motion increases. Over 500 trials, the reliability decreases by at most 6% for the maximum speed considered. Using Kalman state estimation, the dynamic accuracy can be improved by up to 45% when using a three-state dynamic model. The direct mapping solutions and the variant of Tsai's extrinsic algorithm are found to have an expected latency of 33 ms. By comparison, the Nintendo Wii pointing device has an expected latency of just 16 ms.
This thesis finds that no single solution is ideal for all applications. Depending upon the performance constraints and design specifications, it is plausible for either a direct mapping solution or an indirect mapping solution to provide the most suitable implementation. When choosing among competing solutions it is important to carefully consider the advantages and shortcomings of each. In general, this thesis finds direct mapping solutions to have the greatest range of motion for a given measure of accuracy. Indirect mapping solutions are found to support the largest number of users but have a bounded range of motion. The Nintendo Wii is shown to be more robust to changes in position but, unlike the variant of Tsai's extrinsic algorithm, cannot recover the pose of the pointing device. (Abstract shortened by UMI.)
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Shaikh, Amir. "Alternative manipulation devices and strategies in a virtual reality operator-training system." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0001/MQ44039.pdf.
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Faustini, Marco. "Nanopatterning through bottom-up approach : an alternative way for data storage devices." Paris 6, 2011. http://www.theses.fr/2011PA066286.
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Ces travaux de thèse ont consisté à développer de nouveaux systèmes pour le stockage magnétique de données en utilisant une méthode non-lithographique, peu chère et facilement transposable à l’échelle industrielle. Pour ce faire, des films céramiques nanoperforés ont été préparés à partir de solutions sol-gel et de copolymères à blocs permettant l’organisation de la matrice inorganique en utilisant la technique de dépôt « trempage/retrait ». La composition des solutions et les paramètres de dépôts ont été étudiés et optimisés de manière à contrôler les paramètres structuraux des films nanoperforés (diamètre des perforations, distance entre les perforations, etc. ). Une texturation micrométrique peut ensuite être ajoutée à la texturation nanométrique des films par l’utilisation de la lithographie rayons X ; la profondeur des perforations peut être, elle, contrôlée par gravure physique. Les nanostructures obtenus on été utilisée comme substrat pour le dépôt de matériaux magnétiques. Le système le plus prometteur constitué de nanoplots entourés par un film continu et présentant une anisotropie magnétique perpendiculaire on été obtenus en déposant des multicouches Co/Pt par pulvérisation. Les nanoperforations servent de point d’ancrage aux domaines magnétiques et peuvent être utilisées pour créer des nouveaux dispositifs permettant le stockage des données. La méthodologie développée pour la préparation de films nanostructures a également été appliquée à la préparation de matériaux pour application optique et pour la réalisation de dispositifs nanofluidiques
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Loup, Adam. "A Software Framework for Augmentative and Alternative Communication." ScholarWorks@UNO, 2012. http://scholarworks.uno.edu/td/1461.
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By combining context awareness and analytical based relevance computing software, the proposed Augmentative and Alternative Communication (AAC) framework aims provide a foundation to create communication systems to dramatically increase the words available to AAC users. The framework will allow the lexicon available to the user to be dynamically updated by varying sources and to promote words based on contextual relevance. This level of customization enables the development of highly customizable AAC devices that evolve with use to become more personal while also broadening the expressiveness of the user. In order to maximize the efficient creation of conversation for AAC users, the framework provides a lexicon with the ability to obtain words from multiple sources which are then organized according to relevance in a situational context.
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Baynes, Timothy Malcolm. "Analysis of the demagnetisation process and possible alternative magnetic treatments for naval vessels /." New South Wales, Australia : The University of New South Wales, 2002. http://www.library.unsw.edu.au/~thesis/adt-NUN/public/adt-NUN20041203.121450/index.html.
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Thesis (Ph. D.)--University of New South Wales, 2002."a thesis submitted for the degree of Doctor of Philosophy in the School of Physics, Faculty of Science at the University of New South Wales" Also available online.
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Tsai, Dilys Tsai-Hsuan. "A usability assessment of a specific alternative computer input device for users with spinal cord injuries." Thesis, De Montfort University, 2006. http://hdl.handle.net/2086/10708.
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The salient point of this research was to investigate the key factors of assistive devices for people with severe physical disabilities, i.e. spinal cord injury, when selecting and using an input device. The area of study was also concerned with validating a new computer device to enable those individuals with upper-limb impairments to engage the benefits of computer technology, via both user-issue and scientific-based evaluations. A specific methodology, concermng both user-Issue and scientific-evidence, was proposed for the studies related to assistive technology outcome measures. In order to validate the proposed methodology, the research work began with an in-depth survey (Study A), to give an insight into the present selection and utilisation of input devices among those computer users with spinal cord injuries and identify their specific needs when using a computer. Following the findings of this contextual survey, a SCI users' needs hierarchy was proposed for input device selection and use. Specific touchscreen devices, which matched the criteria in the hierarchy, were suggested as a possible solution for users with severe upper-limb disorders. Then, a series of user-centred validation studies, involving a pilot simulation study associated with a dimensional issue of an input device (Study B), followed by usability evaluations at the introductory phase (Study C), after short-term use and training (Study D) and after longer-term use and outcome comparisons (Study E), were carried out. The user perspectives and scientific data obtained from the usability assessments form the SCI subjects were used not only to demonstrate the effectiveness and efficiency of the assistive device, but also to fill the gap between the merely psychological/psychosocial-based measures and the merely scientific-focus evaluation. By merging a specific research technique and a systematic measuring procedure, a conceptual model for evaluating assistive technology outcome measures has been provided for this field of study. Moreover, this research has shown that the integration of user-issue and scientific-evidence can increase the reliability and validity of this type of device outcome measures and, therefore, attain a good match between users and the technology employed.
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Farmand, Maryam. "X-ray Absorption Spectroscopy Characterization of Electrochemical Processes in Renewable Energy Storage and Conversion Devices." Thesis, The George Washington University, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3557518.
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The development of better energy conversion and storage devices, such as fuel cells and batteries, is crucial for reduction of our global carbon footprint and improving the quality of the air we breathe. However, both of these technologies face important challenges. The development of lower cost and better electrode materials, which are more durable and allow more control over the electrochemical reactions occurring at the electrode/electrolyte interface, is perhaps most important for meeting these challenges. Hence, full characterization of the electrochemical processes that occur at the electrodes is vital for intelligent design of more energy efficient electrodes.
X-ray absorption spectroscopy (XAS) is a short-range order, element specific technique that can be utilized to probe the processes occurring at operating electrode surfaces, as well for studying the amorphous materials and nano-particles making up the electrodes. It has been increasingly used in recent years to study fuel cell catalysts through application of the Δ&mgr; XANES technique, in combination with the more traditional X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) techniques. The Δ&mgr; XANES data analysis technique, previously developed and applied to heterogeneous catalysts and fuel cell electrocatalysts by the GWU group, was extended in this work to provide for the first time space resolved adsorbate coverages on both electrodes of a direct methanol fuel cell. Even more importantly, the Δ&mgr; technique was applied for the first time to battery relevant materials, where bulk properties such as the oxidation state and local geometry of a cathode are followed.
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Toback, Andrew Todd. "The effect of alternative fuels and aftertreatment devices on measured mobile school bus emissions /." Full text available online, 2007. http://www.lib.rowan.edu/find/theses.
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Mallon, Kelsey N. "Altering the Gag Reflex via a Hand Pressure Device: Perceptions of Pressure." Miami University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=miami1398622026.
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Smith, Mark Alan. "Improved dynamic stability using FACTS devices with phasor measurement feedback." Thesis, Virginia Tech, 1994. http://hdl.handle.net/10919/42417.
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With an increasing number of regulatory and economic factors making the
operation of power systems more challenging, utilities must take full advantage of
technological advances which allow more flexibility for operation. One of these advances
is the combination of power electronic controllers and compensation devices known as
F1exible AC Transmission Systems (FACTS) technology. This thesis will examine the
ability of FACTS technology to improve dynamic stability when controlled with data
obtained from another recent advancement, phasor measurement units (PMUs). Based on
an overview of the relative capabilities of presently available FACTS devices, a specific
device will be chosen to be modeled in a dynamic stability study. Eigenvalue sensitivity
analysis will be used to determine the optimal placement for this FACTS device in regards
to stability for a test power system. Then a state space model will be developed for the
FACTS compensated test system, and eigenvalue sensitivity and time-domain methods will
be used to determine the optimal controller characteristics for the modeled FACTS device.
Stability results will be verified using eigenvalue analysis and time simulation techniques.Master of Science
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Schilling, Denise Lynn. "Examining alternative seating devices for children with attention deficit hyperactivity disorder : effects on classroom behavior /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/7674.
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Mustaffa, Mohd N. "An alternative user interface for an expanded version of the Computer Aided Teaching System (CATSY)." Virtual Press, 1986. http://liblink.bsu.edu/uhtbin/catkey/459232.
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A new version of a Computer Aided Teaching System, CATSY-3, was created in order to allow greater flexibility and efficiency than older versions of CATSY. In the implementation of CATSY-3, the menu was transferred from the screen to the data tablet. In the process, the control structure of CATSY was rewritten to allow complete freedom of movement from one menu option to any another.A keyboard input feature (KEYIN) is also included in CATSY-3 in order to allow a more rapid mode of menu selection and to allow the option of precision coordinate input. Additional menu options are included in CATSY-3, namely, COPY, MOVE, REFRESH_OBJECT, interactive COLOR change, automatic set-up for input devices, among others.The history and description of various electronic chalkboard` implementations are also presented in this thesis.
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Frick, Bethany Joan. "Multicultural Considerations in Augmentative and Alternative Communication (AAC) Devices for Culturally and Linguistically Diverse AAC Users." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1585242427166751.
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Millet, Barbara. "Design and Evaluation of Three Alternative Keyboard Layouts for a Five-Key Text Entry Technique." Scholarly Repository, 2009. http://scholarlyrepository.miami.edu/oa_dissertations/513.
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Despite the increase in popularity of handheld devices, text entry on such devices is becoming more difficult due to reduced form factors that limit display size, input modes, and interaction techniques. In an effort to circumvent these issues, research has found that five-key methods are effective for text entry on devices such as in-car navigation systems, television and gaming controllers, wrist watches, and other small devices. Five-key text entry methods use four directional keys to move a selector over an on-screen keyboard and an Enter key for selection. Although other researchers have described five-key character layouts using alphabetical order and predictive layouts based on digraph frequencies, there is considerable latitude in designing the rest of a comprehensive on-screen keyboard. Furthermore, it might be possible to capitalize on the relative strengths of the alphabetic and predictive layouts by combining them in a hybrid layout. Thus, this research examines the design of alternative keyboard layouts for five-key text entry techniques. Three keyboard layouts (Alphabetical, Predictive, and Hybrid) were selected to represent standard and less familiar arrangements. The analysis centered on a series of controlled experiments conducted on a research platform designed by the author. In this work, when the immediate usability of three alternative keyboard layouts for supporting five-key text entry was investigated, results indicated no statistically significant differences in performance across the tested keyboards. Furthermore, experimental results show that following immediate usability, but still at the onset of learning, there was no overall difference in performance among the three keyboard layouts across four text types. However, the Alphabetical keyboard surpassed both the Predictive and Hybrid keyboards in text entry speed in typing Web addresses. The nonstandard keyboards performed superior to the Alphabetical keyboards in typing Words/Spaces and Sentences, but performed no better in typing Address strings than the Alphabetical. Use of mixed effects modeling suggested that the longitudinal data was best fitted by a quadratic model. Text entry performance on all three layouts improved as a function of practice, demonstrating that participants could learn the unfamiliar layouts to complete text entry tasks. Overall, there was no indication that use of nonstandard layouts impedes performance. In fact, trend in time data suggests that the learning rates were greater for the nonstandard keyboards over the standard layout. Overall, participants preferred the Hybrid layout. In summary, this dissertation focused on creating and validating novel and effective five-key text entry techniques for constrained devices.
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Sellers, Eric W. "A P300-Based Brain-Computer Interface: Testing an Alternative Method of Communication." Scholar Commons, 2004. https://scholarcommons.usf.edu/etd/1242.
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The current study evaluates the effectiveness of a Brain-Computer Interface (BCI) system that operates by detecting a P300 elicited by one of four randomly presented stimuli (i.e., YES, NO, PASS, END). Two groups of participants were tested. The first group included three ALS patients that varied in degree of disability, but all retained the ability to communicate; the second group included three Non-ALS controls. Each participant participated in ten experimental sessions during a period of approximately 6 weeks. Sessions were conducted either at the participant's home or in the lab. During each run the participant's task was to attend to one stimulus and disregard the other three. Stimuli were presented auditorily, visually, or in both modes. Additionally, on each run, the experimenter would either tell the participant which stimulus to focus on, or ask the participant a question and the participant would focus on the correct "YES/NO" answer to the question. Overall, for each participant, the ERPs elicited by the target stimuli could be discriminated from the non-target stimuli; however, less variability was observed in the Non-ALS group. Comparing across sessions, the within session variability was lower than across session variability. In addition, waveform morphology varied as a function of the presentation mode, but not in a similar pattern for each participant. Offline and simulated online classification algorithms conducted using step-wise discriminant analysis produced results suggesting the potential for online classification performance at levels acceptable for communication. Future investigations will begin to focus on testing online classification performance with real-time feedback, and continuing to examine stimulus properties to determine how to maximize P300 amplitude for individual users.
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Fröbel, Markus Verfasser], Karl [Akademischer Betreuer] [Gutachter] [Leo, and Malte C. [Gutachter] Gather. "Novel Concepts For Alternating Current Operated Organic Light-Emitting Devices / Markus Fröbel ; Gutachter: Karl Leo, Malte C. Gather ; Betreuer: Karl Leo." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://d-nb.info/112918174X/34.
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Fröbel, Markus [Verfasser], Karl [Akademischer Betreuer] [Gutachter] Leo, and Malte C. [Gutachter] Gather. "Novel Concepts For Alternating Current Operated Organic Light-Emitting Devices / Markus Fröbel ; Gutachter: Karl Leo, Malte C. Gather ; Betreuer: Karl Leo." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://d-nb.info/112918174X/34.
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Smith, Kyle. "CFD Investigation of Fluidic Momentum Injection as Alternative to Mechanical High Lift Devices for Boundary Layer Control." Thesis, KTH, Aerodynamik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-164292.
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Syftet med detta projekt i aerodynamik ar att prova en metod för kontroll av gränsskiktets beteende med luftinsprutning. En modern vingprofil vid transsonisk hastighet används, som liknar de som finns på de festa kommersiella flygplan. Koordinater för en experimentell vingprofil som tidigare har använts i vindtunneltester används i denna analys. Vanlig branschprogramvara används, såsom Pointwise för mesh-generering och ANSYS Fluent för CFD-beräkningar. En fullständig svepning av anfallsvinkel, från 0 grader till överstegring, utförs på standardkonfigurationen vid start med tre element, för förhållanden som testats i vindtunnel. ISA-förhållanden vid havsnivå antas för samtliga simuleringar. Simuleringar speglar tidigare publicerade resultat från vindtunneltester. Simuleringar utförs därefter på standardkonfigurationen med tillbakadragna främre slats och fyra olika injektionspunkter. Det visar sig att aven om flygprestanda kan efterliknas vid lägre anfallsvinklar, kan inte CLmax och lyftkraft nås vid vinkeln för överstegring för standardkonfigurationen.The purpose of this computational fluid dynamics investigation was to consider a method for boundary layer control using air injection on a modern transonic airfoil similar to those found on most commercial airliners. Common industry software titles such as Pointwise for mesh generation, and ANSYS Fluent for the CFD computation were implemented. Coordinates for an experimental transonic airfoil which had been used previously in wind tunnel testing were acquired and used in this analysis. A full alpha sweep, from 0 degrees to stall, was performed on the standard three-element configuration at wind tunnel testing conditions. ISA conditions at sea level was assumed for all simulations. These simulations mirrored previously published wind tunnel results. A series simulations were then performed on the standard configuration with retracted leading edge slat and four different injection points. It was found that although the flight performance could be matched at lower angles of attack, the CLmax and lift at the stall angle of the standard configuration could not be achieved.
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Krishnamoorthy, Sreenidhi. "Experimental Testing and Mathematical Modeling of a Thermoelectric Based Hydronic Cooling and Heating Device with Transient Charging of Sensible Thermal Energy Storage Water Tank." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1227299540.
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Rose, Adam. "A Decision Analysis of Left Atrial Appendage Closure as an Alternative to Long-Term Anticoagulation in a Health System's Patients with Atrial Fibrillation." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1542723664655377.
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Clarke, Amie. "Increasing Accurate Set Up of Assistive Technology Devices by Teaching with Behavioral Skills Training." OpenSIUC, 2011. https://opensiuc.lib.siu.edu/theses/647.
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The purpose of paper is to describe a rationale for training staff who work with others with disabilities to use Assistive Technology devices. Current literature describes reasons that Augmentative and Alternative Communication devices are not used based on cost, satisfaction, and difficulty in evaluation. Devices are often abandoned due to ineffective training and increased response effort to operate the device. Previous research on training others to use AT devices is reviewed. A popular behavioral perspective continues to be Behavioral Skills Training. By comparing BST to other common methods of device set up, the current study demonstrates the effectiveness of a BST package.
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Chien, Jui-Yu. "The future and outlook of alternative fuel bus industry and its marketing strategy." CSUSB ScholarWorks, 2002. https://scholarworks.lib.csusb.edu/etd-project/2332.
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According to the current governmental regulations, all diesel buses will be replaced in the United States and the European market within the next ten years. There are over 60,000 buses in the United States and each year over 3,000 new buses of approximately 40 feet in length are purchased. The bus market has a growth rate of four to five percent per year over the last two years. The improvements in technology offered by United States companies prove unsatisfactory in terms of bus performance and the emissions of new buses. The energy crisis in the United States and concern over the health hazards of the diesel fuel exhaust gases and particulates, alternative fuel vehicles are in great demand in the transit market world wide.
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Kullaya, Kosuwan Thompson James Richard Beck Ann R. "Factors that influence adolescents' attitudes toward peers who use augmentative and alternative communication (AAC)." Normal, Ill. : Illinois State University, 2004. http://wwwlib.umi.com/cr/ilstu/fullcit?p3128280.
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Thesis (Ed. D.)--Illinois State University, 2004.Title from title page screen, viewed Jan. 11, 2005. Dissertation Committee: James R. Thompson, Ann R. Beck (co-chairs), Maureen E. Angell, Stacey J. Bock, W. Paul Vogt. Includes bibliographical references (leaves 109-126) and abstract. Also available in print.
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Finnie, Sara Elizabeth. "MUSIC THERAPISTS’ EXPERIENCES WITH CLIENTS WITH AUTISM SPECTRUM DISORDER WHO USE AUGMENTATIVE AND ALTERNATIVE COMMUNICATION." UKnowledge, 2018. https://uknowledge.uky.edu/music_etds/127.
Full textAbstract:
Music therapists frequently work with clients with Autism Spectrum Disorder (ASD) who use Augmentative and Alternative Communication (AAC). The purpose of this study was to gather information on music therapists’ current experiences with AAC training as well as music therapists’ perceptions of their own communication abilities when communicating with clients who have ASD using their preferred AAC system. The researcher invited 7,279 board-certified music therapists to participate in this study via email, of which 366 completed the survey. Participants reported most often providing services to children and adolescents with ASD, and frequently using electronic AAC and electronic apps with their clients with ASD. The majority (71.2%) of participants stated that they would like additional training in the use of AAC. Of the music therapists who had participated in previous AAC training, many had received training at work or by an SLP or other certified professional. Results of this study provide information about the current practices and perceptions of board-certified music therapists working with clients with ASD.