Dissertations / Theses on the topic 'Conversion technology'
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de, Albuquerque Fragoso Danielle Munick. "Lignin conversion to fine chemicals." Thesis, University of Glasgow, 2018. http://theses.gla.ac.uk/30847/.
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The large availability of Kraft lignin as an industrial by-product and its polyaromatic characteristic, is ideal to consider the potential for recycling it into fine chemicals. To depolymerise lignin, solvolysis and hydrogenolysis experiments were performed. This research considered whether the low yields of products (fine chemicals) were related to the low content of β-O-4 bonds or if it was also associated to the dissolution of lignin in the solvent solution employed in the reactions. The type of solvents chosen to check the dissolution effect were those with low cost and were more sustainable than traditional solvents. Water, ethanol, isopropanol (IPA) and acetone were used. The water mixtures were applied in the tests in various proportions (25:75, 50:50, 75:25 solvent/water v:v). Due to their ability to break C-C and C-O bonds in lignin model compounds [1][2], the efficiency of platinum and rhodium in these reactions supported on alumina was also studied. It was found that the non-catalysed (solvolysis) and catalysed reactions showed different selectivities but similar overall yields ~ 10 % wt of monomeric phenols. The difficulty in increasing yields was mainly associated with the highly condensed character of Kraft lignin and re-polymerisation issues. To achieve an understanding of Kraft lignin depolymerisation, isotopic labelling reactions were completed in the presence of deuterated solvents as well as deuterium gas. This gave information on how Kraft lignin depolymerises, the influence of solvent to products formation and the involvement of hydrogen in the rate determining steps in the reactions. These results have led to an initial mechanistic understanding on how this complex molecule may yield alky-phenolic compounds. It was revealed that the solvent was directly involved in the products’ formation and that they were not generated by simple thermolysis. In addition, the presence of catalysts and hydrogen influenced product formation. The compounds showed different kinetic isotopic values, suggesting that each of these molecules came from individual mechanisms, highlighting the complexity of their formation. This was a relevant study as most of lignin depolymerisation mechanistic insights are based on model compounds and not on lignin itself. It was of interest to this project to explore not only different catalysts and their relationship to lignin depolymerisation, but also different lignin types. A simple pre-treatment for lignin extraction using sawdust (from oak and birch wood) in a Parr autoclave reactor in the presence of hydrogen, solvent and high temperature was developed. The lignins obtained after the pre-treatment were named parr-lignin and successfully resulted in polyaromatic molecules with less condensed character compared to lignins from Soda or Kraft pulping. Reactions were carried out with these lignins and a sugar-cane lignin. 4 5 Different catalytic systems with these lignins were investigated and how depolymerisation was affected by the metal and support used. The catalysts involved in the reactions included platinum, rhodium, nickel and iron. Various supports such as alumina, zirconia and carbon were tested along with the metals described. It was found that the supports were not inert in these experiments presenting catalytic activity. Materials with low surface area (zirconium catalysts) gave a poor performance compared to the others. In addition, nickel, a non-noble metal, showed as good a catalytic effect in the depolymerisation of these lignins as Pt and Rh. The components in the system influenced the reactions to different extents, especially product distribution. The catalysts had different selectivities and the solvents were not only dissolving lignin but also influencing the results. GPC analysis was performed to give an overview of the condensed level of these lignins and degrees of depolymerisation compared to the original material. GC-MS enabled the identification and quantification of 18 monomeric compounds. The post reaction characterisation of selected alumina catalysts (Pt/Al2O3, Ni/Al2O3 and Al2O3) was performed using XRD, BET, CHN, TPO and Raman Analysis to study the nature of the carbonaceous layer deposited on these materials. The work showed that after reaction the catalysts turned black in colour and the carbon laydown consisted of not only one simple type of carbon, and included graphitic species. The amount of carbon deposited depended on the type of lignin. Oak and birch parr-lignins had the highest and lowest amount of carbon over the catalysts respectively. No obvious trend relating to the type of catalyst, lignin and solvent used to the carbon nature was identified. This work showed that lignins with less condensed nature were less susceptible to solvolysis and more to hydrogenolysis. For example, sugar-cane lignin gave 3.9% of phenolic compounds in the solvolysis while reaction with Rh/Al2O3 gave 12.9% of products. This indicated that more selective cleavage of bonds were promoted by heterogenous catalysts. The results suggested that some compounds were mainly generated via dealkylation and hydrodeoxygenation, allowing a future possibility to generate target molecules. These results were mainly due to the presence of more labile bonds, vulnerable to hydrogenolysis. Highlighting that prior to depolymerisation, the pre-treatment used to extract lignin must be appropriate to avoid depletion of the alkyl-aryl ether bonds (β-O-4 bonds, especially) relevant for fine chemicals generation.
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Grabbe, Mårten. "Marine Current Energy Conversion : Resource and Technology." Licentiate thesis, Uppsala University, Electricity, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-113365.
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Grabbe, Mårten. "Hydro-Kinetic Energy Conversion : Resource and Technology." Doctoral thesis, Uppsala universitet, Elektricitetslära, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-195942.
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The kinetic energy present in tidal currents and other water courses has long been appreciated as a vast resource of renewable energy. The work presented in this doctoral thesis is devoted to both the characteristics of the hydro-kinetic resource and the technology for energy conversion. An assessment of the tidal energy resource in Norwegian waters has been carried out based on available data in pilot books. More than 100 sites have been identified as interesting with a total estimated theoretical resource—i.e. the kinetic energy in the undisturbed flow—in the range of 17 TWh. A second study was performed to analyse the velocity distributions presented by tidal currents, regulated rivers and unregulated rivers. The focus is on the possible degree of utilization (or capacity factor), the fraction of converted energy and the ratio of maximum to rated velocity, all of which are believed to be important characteristics of the resource affecting the economic viability of a hydro-kinetic energy converter. The concept for hydro-kinetic energy conversion studied in this thesis comprises a vertical axis turbine coupled to a directly driven permanent magnet generator. One such cable wound laboratory generator has been constructed and an experimental setup for deployment in the river Dalälven has been finalized as part of this thesis work. It has been shown, through simulations and experiments, that the generator design at hand can meet the system requirements in the expected range of operation. Experience from winding the prototype generators suggests that improvements of the stator slot geometry can be implemented and, according to simulations, decrease the stator weight by 11% and decrease the load angle by 17%. The decrease in load angle opens the possibility to reduce the amount of permanent magnetic material in the design.
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Murray, Robert T. "Nonlinear wavelength conversion with optical fibre based technology." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/25624.
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It is no exaggeration to state that the low-loss optical fibre has revolutionised the way in which we as a society lead our lives. The transfer and management of vast tracts of data generated minute by minute world over is only possible due to the development of the optical fibre and corresponding optical amplifiers, necessary for the implementation of telecommunications networks over large distances. Outside of the telecommunications sphere, the optical fibre has also made a huge impact on the laser market in the past three decades, due to the inherently robust nature and alignment-free operation of fibre based devices. Fibre lasers have now penetrated into the manufacturing market, and are finding increasing applications in numerous areas from medicine to defence. Typical fibre laser sources are constrained to operate in the emission bands of common rare-earth dopants, such as, ytterbium, erbium, or thulium. However, it is possible to extend the spectral coverage of standard fibre lasers through nonlinear conversion techniques. The temporal properties of pulsed laser sources, can be similarly manipulated, through the combined management of nonlinearity and dispersion. The work presented in this thesis is based upon these two themes of spectral and temporal diversity. Firstly, I will examine fibre-based parametric wavelength conversion, demonstrating fibre laser sources in the visible and near-visible spectral regions, suitable for bio-photonics imaging applications. Secondly, I will look at fibre-based nonlinear chirped pulse amplification, in particular, the design and implementation of a femtosecond μJ level source for future experiments in nonlinear optics. Both areas of research are tied together by the common thread of utilising new and emerging optical fibre based technology for nonlinear wavelength conversion.
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Abedini, Amin. "Piezoelectric Energy Harvesting via Frequency Up-conversion Technology." OpenSIUC, 2019. https://opensiuc.lib.siu.edu/dissertations/1716.
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Ambient energy harvesting has attracted significant attention over the last years for applications such as wireless sensors, implantable devices, health monitoring systems, and wearable devices. The methods of vibration-to-electric energy conversion can be included in the following categories: electromagnetic, electrostatic, and piezoelectric. Among various techniques of vibration-based energy harvesting, piezoelectric transduction method has received the most attention due to the large power density of the piezoelectric material and its simple architectures. In contrast to electromagnetic energy harvesting, the output voltage of a piezoelectric energy harvester is high, which can charge a storage component such as a battery. Compared to electrostatic energy harvester, the piezoelectric energy harvester does not require an external voltage supply. Also, piezoelectric harvesters can be manufactured in micro-scale, where they show better performance compared to other energy harvesters, owing to the well-established thick-film and thin-film fabrication techniques. The main drawback of the linear piezoelectric harvesters is that they only retrieve energy efficiently when they are excited at their resonance frequencies, which are usually high, while they are less efficient when the excitation frequency is distributed over a broad spectrum or is dominant at low frequencies. High-frequency vibrations can be found in machinery and vehicles could be used as the energy source but, most of the vibration energy harvesters are targeting at low-frequency vibration sources which are more achievable in the natural environment. One way to overcome this limitation is by using the frequency-up-conversion technology via impacts, where the source of the impacts can be one or two stoppers or more massive beams. The impact makes the piezoelectric beam oscillate in its resonance frequency and brings nonlinear behavior into the system.
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Yuen, Katarina. "System Aspects of Marine Current Energy Conversion." Licentiate thesis, Uppsala University, Electricity, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-113339.
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Free-flowing water currents such as tides and unregulated water courses could contribute to world electricity production given the emergence of robust technical solutions for extracting the energy. At Uppsala University, a concept for converting water currents to electricity using a vertical axis turbine with fixed blade pitch and a direct drive permanentmagnet generator is studied. A system approach is desired, and in this thesis, a first analysis of two system components, the generator and the turbine, is presented. This thesis also deals with some issues concerning the design and construction of a low speed generator for this application. An experimental generator for verification of simulations has been designed and constructed. For the electromagnetic design, a FEM simulation tool has been used. The construction work has given valuable practical experience concerning for example handling permanent magnets and winding the generator with cable. Simulations and measurements of the experimental generator have been carried out for different speeds and loads. The generator can operate at the speeds and loads corresponding to maximum power capture for different turbines for water current velocities between approximately 0.5 and 2.5 m/s. At higher water current velocities the turbines may need to be run at a tip speed ratio that gives a lower power capture in order to limit the electrical currents in the generator, cavitation of the blades, or mechanical loads. Comparisons of measurements and simulations show an agreement. The FEM simulation tool can be used to simulate and design electrical machines with a low electrical frequency, i.e. 2–16 Hz.
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Samarah, Imad M. "Collaboration technology support for knowledge conversion in virtual teams /." Available to subscribers only, 2006. http://proquest.umi.com/pqdweb?did=1240701241&sid=4&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Wilkinson, Stuart. "Barley derived spent grains : conversion to bioethanol." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/33865/.
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Brewers spent grains (BSG) are an abundant co-product from the beer brewing industry. The current predominant use for BSG is as cattle feed. However, this is a low value use. As such, higher value uses for BSG are being sought. One such option is the production of bioethanol from the polysaccharides (cellulose and hemicellulose in the lignocellulosic matrix) found in BSG, and this thesis aimed to develop this process. This was achieved through investigating and attempting to optimise a range of different pre-treatments in order to enhance the subsequent cellulolytic enzyme saccharification yields to produce a high glucose concentration feedstock which could then be fermented to produce bioethanol. For the pre-treatment step of the process, a wide range of protocols were investigated and optimised (at high solids loading; ≥25% w/v). These included dilute acid and alkali hydrothermal, alkaline peroxide, caustic (NaOH) and microwave based autohydrolytical protocols which were all capable (under optimal conditions) of achieving close to 90% theoretical glucose yields when using an excess of cellulolytic enzyme. Optimisation of the enzymatic saccharification step was attempted and involved using a batch-fed protocol, with supplementary enzymes, and a high-torque mixing system were still only able to achieve ca. 43% theoretical glucose yields when operating at 15% w/v solids loading. Limited saccharification yields appear to be the rate limiting step for bioethanol production from BSG as it limited the concentration of glucose in the feedstocks produced. In addition, entirely biological routes to generate bioethanol were investigated using consolidated bioprocessing (CBP), which entailed using a consortium of fungal microorganisms. A primary filamentous fungal species was used as a cellulolytic enzyme factory whilst a yeast strain was used to ferment any liberated sugars to ethanol. From all of the fungal based CBP systems tested the traditional saké fermentation system (A.oryzae and S.cerevisiae NCYC479) was shown to achieve the highest ethanol yields (ca. 37 g/L within 10 days).
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Li, Xiangtao. "High-speed analog-to-digital conversion in SiGe HBT technology." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24652.
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Thesis (Ph.D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008.Committee Chair: Cressler, John D.; Committee Member: Laskar, Joy; Committee Member: Lee, Chin-Hui; Committee Member: Morley, Thomas; Committee Member: Papapolymerou, John
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Delgado, Guillermo Guadalupe. "Treatment of RO concentrate using VSEP technology." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2009. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.
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Yaesoubi, Maziar. "Machine Transcription Conversion Between Perso-Arabic and Romanized Writing Systems." Thesis, Linköpings universitet, Institutionen för datavetenskap, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-61029.
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Perso-Arabic script is the official writing system in Iran. Romanized transcriptions, based on phonology of Persian, have been extensively used in electronic communications especially on Internet. Dealing with the conversion between these two types of writing systems has been an interesting topic in Natural Language Processing. Similar to Machine Translation, these conversions can be applied at different grammatical layers; such as sentence, phrase or word layer. In this thesis, by choosing Dabire as a standard Romanized transcription, we introduce two approaches to achieve such conversions at word level. In Lexicon-based approach we use Finite State Technology for bi-directional conversion between Perso-Arabic and Dabire. The second approach uses association analysis for statistical conversion from Perso-Arabic to Dabire.
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Burrell, Marcia M., and Clayton Cohn. "Integrating Technology into the Mathematics Classroom: Instructional Design and Lesson Conversion." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-79535.
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The use of technology in Kindergarten to grade 12 classrooms provides opportunities for teachers to employ mathematical rigor, to integrate problem solving strategies and to extend mathematical ways of knowing (Drier, Dawson, & Garofalo, 1999). The presentation consists of two parts. One investigation maps secondary mathematics technology lessons and materials to the elementary school mathematics standards and converts the mathematics concepts to manageable elementary school lessons. The other investigation analyzes pre-service teacher lessons written using ASSURE instructional design format. The major aims of this paper are to present two teacher preparation practices, one for secondary mathematics pre-service teachers (converting secondary materials to elementary materials) and the other for elementary mathematics pre-service teachers (writing lessons using the ASSURE model).
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Kalinauskaitė, Solveiga. "Environmental and energy efficiency evaluation of straw treatment and conversion technology." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2014~D_20141223_145125-20389.
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Research goal. We seek to validate optimal composition of straw biomass fuel and energy efficiency of straw utilization for energy needs, to assess straw biomass fuel preparation technology in respect to energy efficiency, and to determine emissions that are generated during straw combustion. Research objectives. The following objectives were planned to reach the goal of the research: 1) Process analysis of preparation of biomass fuel (pellets and briquettes) for burning, 2) Validation of mixture of lime additive (CaO) into straw biomass fuel, 3) Property analysis of prepared biomass fuel, 4) Measurement and assessment of emissions generated while burning straw biomass fuel, 5) Assessment of energy consumption by straw pellet production equipment.Tyrimų tikslas. Pagrįsti šiaudų biokuro optimalios sudėties paruošimo ir panaudojimo energinėms reikmėms efektyvumą, atlikti šiaudų biokuro paruošimo technologijos energinį vertinimą ir nustatyti deginimo metu išskiriamas emisijas. Tyrimų uždaviniai. Tyrimų tikslui pasiekti numatyta: 1) Atlikti šiaudų biokuro (briketų ir granulių) paruošimo deginimui technologinę analizę; 2) Pagristi kalkių priedo (CaO) įmaišymo į šiaudų biokuro sudetį tikslingumą; 3) Ištirti pagaminto šiaudų biokuro savybes; 4) Nustatyti ir įvertinti šiaudų biokuro deginimo metu išskiriamas emisijas; 5) Įvertinti šiaudų granulių gamybos technologinės įrangos energijos sanaudas.
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Chiu, Chuang-Wei. "Catalytic conversion of glycerol to propylene glycol synthesis and technology assessment /." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4421.
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Thesis (Ph.D.)--University of Missouri-Columbia, 2006.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 May 1, 2009) Vita. Includes bibliographical references.
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Austin-Crowe, Joseph W. "Analogue-to-digital conversion and image enhancement using neuron-mos technology." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2000. https://ro.ecu.edu.au/theses/1342.
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This thesis describes the development of two novel circuits that use a newly developed technology, that of neuron-MOS, for the purposes of analogue-to-digital conversion and image enhancement. Neuron-MOS has the potential to reduce both the complexity and number of transistors required for analogue and digital circuits. A reduced area, low transistor-count- analogue-to-digital converter that is suitable for inclusion in a massively parallel array of identical image processing elements is developed. Supporting the function of the array some fundamental image enhancement operations, such as edge enhancement, are examined exploiting the unique features of neuron-MOS technology.
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Jäger, Nils. "Techno-economic assessment of conversion processes for biomass to products : technology concepts for the conversion of biomass and biogenic residues." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8281/.
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Within the framework of this techno-economic assessment, the possible contribution of the platform technology Thermo-Catalytic Reforming (TCR®) to reduce CO2 emissions, save resources, and solve waste problems was evaluated. The selection of the feedstocks included samples of sewage sludge, woody biomass, algae, organic fraction of municipal solid waste, leather residues, peat, lignite, and selected mixtures thereof. These feedstocks were processed in a lab-scale TCR plant with a capacity of 2 kg/h and converted into oil, gas, and carbonisates. It is targeted to utilize these products as substitutes for fossil resources for energetic and material usage. For each feedstock, optimum process parameters, correlations regarding feedstock and product composition and yields, and measures to optimize the technology, were identified. The experimental results were used as a basis for the economic evaluation. To identify promising value chains, the levelized costs/levelized revenues approach was adopted for multi-product processes. State of the art technologies and the products thereof were the benchmark. By linking the results of the technical and economic evaluation, the optimum utilization pathways for the processed feedstocks, related products, and potentials to increase the competitiveness of the technology were identified.
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Liu, Yuan-Ping. "Design and implementation of piezoelectric technology based power devices." Cachan, Ecole normale supérieure, 2009. http://tel.archives-ouvertes.fr/tel-00505837/fr/.
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Le travail présenté dans ce mémoire s'inscrit dans le cadre de l'utilisation de matériaux piézoélectriques pour la réalisation de composants passifs dans des applications de conversion d'énergie électrique. Le travail débute avec l'étude et le dimensionnement de deux convertisseurs d 'une puissance de 10 watt intégrant un transformateur piézoélectrique, l'un pour des applications d'alimentation stabilisée de 15 V (convertisseur DC/DC) et l'autre servant a l'alimentation de lampes fluorescentes a cathode froide utilisées pour le retro-éclairage d'écrans TFT de 32 pouces. L'idée étant que le transformateur piézoélectrique présente, dans ces applications, un certain nombre d'avantages compare au transformateur électromagnétique, comme une plus grande compacité et une meilleure compatibilité électromagnétique. L'originalité du travail repose sur la méthode de dimensionnement du transformateur qui n'est plus base sur Le principe de charge optimale mais qui introduit la notion de courant mécanique ou de vitesse maximale de vibration. Cette technique permet également de prédire l'élévation de température ainsi que les pertes du transformateur. On s'intéresse ensuite a l'optimisation et a la gestion de l'énergie au sein du transformateur piézoélectrique. La commutation introduisant des non-linéarités dans son fonctionnement, Le concept de cycle de travail a été introduit permettant une étude et des comparaisons des différentes architectures de conversion. Cela a permis la mise au point d'un nouveau redresseur contr6le par la vitesse de vibration. Ce redresseur actif a été transpose avec succès dans des appliIn this dissertation, piezoelectric materials were adopted in various power devices, and were further developed more specifically to power converters. The main purpose of this dissertation is to use piezoelectric transformer to replace the conventional electromagnetic transformer in power converters. A piezoelectric transformer based converter may reduce the electromagnetic interferences (EMI), the thickness ofthe converters and may increase the power density of the converter. Cold cathode fluorescent lamp (CCFL) based inverters, DC/DC converters and optimization of the piezoelectric layer fed rectifiers are the three main parts in this dissertation. Previous researches used the concept of the optimal loading condition as the major design parameter. However, practical power converters require regulating output current or voltage. Considering the power converters with current or voltage regulation, the concept of the optimal loading condition is no longer suitable to be the major design parameter. In this dissertation, the vibration velocity was adopted as the major design parameter, which makes the design procedure of piezoelectric transformers easier and clearer compared to the usual design rule. The proposed design procedure can predict the temperature rise as well as the losses of the piezoelectric transformers clearly. Both cold cathode fluorescent lamp based inverters and DC/DC converters can be designed to fit the requirements and the specifications well by the proposed design procedure. A 32 inches LCDTV inverter and a lOWatt step-down DC/DC converter were developed successfully, based on the design procedure detailed in this thesis. In addition, although the piezoelectric transformer itself does not radiate EMI , it still remains the conducted EMI problem. Due to the effect of parasitic capacitors and to the specific effect of the rectifier connected to the piezoelectric transformers, the EMI behaviour of the piezoelectric transformer based converter is quite different from typical converters. The model and analysis of the conducted EMI were studied and detailed in this dissertation. On the other hand, a piezoelectric layer fed rectifier is a non-linear device, which is not easy to analyze in general. The concept of work cycle analysis was proposed to simplify the analysis and the design procedure. Based on these work cycle analysis, a new concept of velocity controlled piezoelectric layer fed rectifier was proposed to optimize the energy flow out of the piezoelectric layer. This technique, also presented herein, was applied successfully to the structural damping.
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Liu, Qintao. "Conversion of triacylglycerols into monoacylglycerols by penicillium roquefortii." Thesis, Sheffield Hallam University, 1998. http://shura.shu.ac.uk/3098/.
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The synthesis and use of monoacylglycerols in food systems havc been reviewed. The use of monoacylglycerols alone or in combination with free fatty acids as food preservatives has been discussed. Model systems have been devised to produce monoacylglycerols (MAGs) from butter and Shea oils with two strains of Penicillium roquefortii, FRR 2456 (isolated from a spoilt melon) and Wisbey PJ (a commercial dairy strain) A semi-micro method was developed using Preparative Thin Layer Chromatography (PTLC) and Gas Chromatography - Mass Spectrometry (GC-MS) of the MAG trimethylsilyl ether derivatives to determine the identification, fatty acid composition and structural isomers of the individual MAG. The main monoacylglycerols produced by spores and emerging mycelium were 1(3)-monoacylsn-lycerols (in suspension culture). Monopalmitin was the major MAG from butter and Shea oils. Monoacylglycerols produced by fungal mycelium (in solid-state culture) were mainly the 1 (3 )-monoacyl-sn-glycerols although approximately 30% were present as 2-monoacyl-snglycerols. Again the main MAG was monopalmitin. It suggested that P. roquefortii produced two lipases, one during germination with specificity to the sn-2 position in the original triacylglycerols (TAGs) and one L3-specific during growth of the fungal mycelium. In addition, flavour compounds, methyl ketones and y-lactones, were found in solid-state culture. The composition of the MAGs formed by lipolysis using a commercial lipase (E.C.3.1.1.3) with 1,3- specificity gave the expected 2-isomers when butter oil was the substrate but gave 1 (3)monostearin rather than the expected 2-monoolein when Shea oil was the substrate. It suggested that acyl migration occurred due to the reactive nature of the original oleate group at the sn-2 position in the Shea oil TAGs. There were no significant differences with fungal strain or temperature of incubation (10 °C and 25°C) on the composition of the MAGs. The mechanism of formation of MAGs from butter and Shea oils has been discussed. It has been suggested that l(3)-MAGs together with free fatty acids may be part of a natural antimicrobial system in high pH foods such as blue mould-ripened cheese where growth of foodborne pathogens such as Listeria monoGytogcnes can be a problem from time to time
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Alwaer, Ayad Almakhzum Mohamed. "A prototype desalination system using solar energy and heat pipe technology." Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2455.
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Thesis (DTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2016.The water desalination process needs large quantities of energy, either directly from fossil fuel or electricity from the national grid. However, these sources of energy significantly contribute to problems such as global warming in addition to creating a drain on the economy, due to their high cost. This dissertation is a description of the research undertaken with the aim of producing a water desalination prototype; a novel approach that was designed using state-of-the-art solar water heating equipment, incorporating the technologies of evacuated tubes and heat pipes. During the execution of the project, various modifications to the original commercially-available solar water heating system were attempted, each aimed at increasing the production of pure water. Finally, the system proved capable of producing a reasonable amount of pure water after twelve lengthy indoor experiments conducted in a laboratory in the department of Mechanical Engineering at the Cape Peninsula University of Technology, Bellville Campus, Cape Town, South Africa. Each experiment lasted five days on the basis of seven hours of exposure to an average amount of simulated solar radiation, followed by seventeen hours daily of inactivity and partial cooling down of the system.
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Erixon, Mats. "Design of a Direct-conversion Radio Receiver Front-end in CMOS Technology." Thesis, Linköping University, Department of Science and Technology, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1197.
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In this Master's thesis, a direct-conversion receiver front-end has been designed in a 0.18um CMOS technology.
Direct-conversion receivers (DCR) have obvious advantages over the heterodyne counterpart. Since the intermediate frequency (IF) is zero, the problem of image is circumvented. As a result, no front-end image reject filter is required and the channel selection requires only a low-pass filter, which makes it easy to integrate directly on chip. However, the DCR also suffers from several drawbacks such as extreme sensitivity to DC offsets, 1/f noise, local oscillator (LO) leakage/radiation, front-end nonlinearity and I/Q mismatch. This implies very high demands on the DCR front-end.
The front-end comprises a low-noise amplifier (LNA) and a mixer. Different LNA and mixer architectures has been studied and from the mentioned inherited problems with direct conversion, one proposal for a solution is a differential source degenerated LNA and a differential harmonic mixer, which has been designed and simulated.
The LNA has a gain of 12dB, a noise figure of 3.6dB and provides a return loss better than -15dB. The overall noise figure of the signal path is 8dB and the overall IIP3 and IIP2 is -12dBm and 31dBm, respectively.
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Boström, Cecilia. "Electrical Systems for Wave Energy Conversion." Doctoral thesis, Uppsala universitet, Elektricitetslära, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-140116.
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Wave energy is a renewable energy source with a large potential to contribute to the world's electricity production. There exist several technologies on how to convert the energy in the ocean waves into electric energy. The wave energy converter (WEC) presented in this thesis is based on a linear synchronous generator. The generator is placed on the seabed and driven by a point absorbing buoy on the ocean surface. Instead of having one large unit, several smaller units are interconnected to increase the total installed power. To convert and interconnect the power from the generators, marine substations are used. The marine substations are placed on the seabed and convert the fluctuating AC from the generators into an AC suitable for grid connection. The work presented in the thesis focuses on the first steps in the electric energy conversion, converting the voltage out from the generators into DC, which have an impact on the WEC's ability to absorb and produce power. The purpose has been to investigate how the generator will operate when it is subjected to different load cases and to obtain guidelines on how future systems could be improved. Offshore experiments and simulations have been done on full scale generators connected to four different loads, i.e. one linear resistive load and three different non-linear loads representing different cases for grid connected WECs. The results show that the power can be controlled and optimized by choosing a suitable system for the WEC. It is not obvious which kind of system is the most preferable, since there are many different parameters that have an impact on the system performance, such as the size of the buoy, how the generator is designed, the number of WECs, the highest allowed complexity of the system, costs and so on. Therefore, the design of the electrical system should preferably be carried out in parallel with the design of the WEC in order to achieve an efficient system.Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 727
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Edwards, Christopher Francis. "Radiation hard CMOS circuits in isolated substrate technology for analogue to digital conversion." Thesis, University of Southampton, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266942.
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Eustis, John Michael. "Surface finishing technology selection and work team development study in a product conversion." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/32142.
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Johansson, Ramnäs Tobias, and Christoffer Wern. "Office Open XML conversion with integrated result-altering GUI." Thesis, Linköpings universitet, Medie- och Informationsteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-119988.
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Yooba is a small company based in Norrköping and they are developing a software tool to easily create and manage applications for iPads and Windows tablets. The environment where to one creates applications is called Yooba Studio and a missing feature that has been requested by their users is a PowerPoint-file importer. PowerPoint, or Microsoft PowerPoint, is a software used to create presentations. To store the presentation data an open XML standard is used called Office Open XML, often shorten OOXML or Open XML. This master thesis will explain how the information inside a OOXML presentation package PPTX can be stored and converted into a new presentation structure, Yooba XML. The thesis work will also explain how an interface, through user tests and prototyping, can be developed to present, for the user, differences when importing between the source program and the final result in Yooba Studio. The developed interface will involve the user in the importation in such way that the user will be the one altering how some of the differences should be imported. The results of this thesis is a working integrated PPTX-file importer where the user can both see statistics over how successful the import were and be able to customize how the final importation result should be.
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Nurika, Irnia. "Mechanisms of lignocellulosic conversion by the brown rot fungus Serpula lacrymans." Thesis, University of Warwick, 2013. http://wrap.warwick.ac.uk/59158/.
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Cost effective processing of wheat straw using solid state fermentation (SSF) would provide a source for value added chemicals from agricultural waste biomass. Fungi natural breakdown lignocellulosic biomass hence could have received a lot of attention. In this study the ability of S. lacrymans to convert straw waste was compared with other Basidiomycetes (Postia placenta, Phanerochaete chrysosporiom, and Schizophyllum commune). S. lacrymans out performed the other Basidiomycetes both in its growth (as measured by ergosterol and fatty acid production (linoleic acid);18:2n6c) , and in the comounds released which included; total soluble phenols, total reducing sugars, and low molecular organic chemicals (MW<400). Non-enzymatic breakdown requiring the presence of Fe2+ was also demonstrtated and influenced by the production of quinone and low molecular organic acid. The amount of the fungal extract used and the concentration of chelator/reducing agents also affected the production of Fe2+. Changes in the lignocellulose structure was also detected as key functional group, such as the pyranose ring and aromatic skeletal vibration were significantly reduced following culture with S. lacrymans and a significant reduction in mass was measured. Iron reductase genes IR1 and IR2 suspected to be involved in the lignocellulose degradation were cloned. It seems that these genes are more closely related to the cellulose binding module (CBM) family instead of cellobiose dehydrogenase (CDH) genes as first suspected. IR1 has an open reading frame of 774 bp which encoding 258 amino acid (55 kDa), whilst IR2 642 bp encoding 214 amino acid ( 49 kDa). The IR1 gene contains a CBM1 domain which is lacking in IR2. Gene expression analysis using qRT-PCR showed that in the early stage of fungal growth, the level of IR2 genes expression was higher than IR1 while IR1 became more dominant in the latter stages of culture. The time at which these genes are highly expressed correlated with the release of soluble and aromatic phenolic compounds. The functionality of the recombinant IR1 and IR2 on the decomposition of lignocellulose was shown using several assays including; iron reductases, nitrated lignin and the reduction of electron acceptor (DCPIP). In addition, using both synthetic and nature sources of cellulose or lignocellulose (Avicel and wheat straw powder) the recombinant IR proteins were shown to break down cellulose. This suggested that these enzymes represent a significant addition to those currently used within biomass based biorefineries.
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Galileu, Speranza Lais. "Development of a new route for direct conversion of wet algae to biodiesel." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7591/.
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Algae have been studied as a potential biodiesel feedstock by identifying on a global scale suitable cultivation locations for three specific cases (EU, US and Brazil) based on the area requirements. A direct conversion of oil harvested from wet algae to biodiesel was undertaken using ethanol at supercritical conditions, eliminating the use of catalyst, feedstock drying and the oil extraction steps. Chlorella vulgaris with 7.3% wt. lipid content was characterised (by elemental, chemical and thermal analyses) and used to assess the supercritical ethanol approach. A biodiesel yield of 47.5% wt. was achieved in a flow reactor at 260°C, 75 bar, aqueous algae concentration of 6 mg·mL-1 and 2 mL·min-1 flowrate. This result demonstrates the advantages of the flow reactor over a batch process where the maximum biodiesel yield was 26% wt. after 6 hours. A life cycle analysis of the proposed route showed that biodiesel yield must exceed 60% wt. to make the process competitive when compared to the traditional route of oil extraction and catalyst transesterification adopted to algae biodiesel production. In comparison to the soybean biodiesel, the use of algae as feedstock would not be justified unless improvements to reduce energy consumption are made.
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Sullivan, Kirk Patrick Haig. "Synthesis-by-analogy : a psychologically-motivated approach to computer text-to-speech conversion." Thesis, University of Southampton, 1992. https://eprints.soton.ac.uk/250078/.
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Acocella, Angela J. (Angela Josephine). "System model of small-scale gas-to-methanol conversion by engine reformers." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98548.
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Thesis: S.M. in Technology and Policy, Massachusetts Institute of Technology, Engineering Systems Division, 2015.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 (pages 88-93).
As global energy demands grow and environmental concerns over resource extraction methods intensify, high impact solutions are becoming increasingly essential. Venting and flaring of associated natural gas represents significant environmental and financial losses yet it continues in the North Dakota Bakken oil play. The valuable gas resource is wasted due to unfavorable economics and limited pipeline capacity. Similarly in India, underdeveloped gas transport infrastructure and restrictive regulatory frameworks prevent distribution and marketing of natural gas from the northeast regions, leaving it stranded in marginal fields. This thesis establishes a techno-economic model, utilizing Aspen Plus chemical processing software, and a discounted cash flow model to estimate economic feasibility of implementing MIT engine reformer-based gas-to-liquids (GTL) systems in the US or India. The system reforms natural gas via partial oxidation into synthesis gas (syngas) in the cylinders of an internal combustion engine, and can significantly reduce capital costs over conventional GTL reforming processes. The engine is operated in fuel rich conditions to generate the syngas, which is synthesized into methanol and dimethyl ether (DME). Once produced on-site, these liquids are more easily transported than gases. This study assesses the regulatory structures surrounding the upstream methane resource and downstream end product marketability for three scenarios: use of DME to replace existing local (1) diesel and (2) liquefied petroleum gas (LPG), or (3) sale of methanol as a commodity chemical on domestic or global markets. The analysis shows the system is economical in both locations. In the US, the minimum economically efficient production capacity with a 1-2 year payback period is 400,000- 860,000 standard cubic feet per day (scfpd) of natural gas for the range of end use scenarios considered. Differences in costs and product market characteristics in India result in a minimum efficient capacity of 330,000-810,000 scfpd of natural gas for the three scenarios.
by Angela J. Acocella.
S.M. in Technology and Policy
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White, John Kenton. "Mid-wave infrared HgCdTe photodiode technology based on plasma induced p-to-n type conversion." University of Western Australia. School of Electrical, Electronic and Computer Engineering, 2005. http://theses.library.uwa.edu.au/adt-WU2005.0128.
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[Truncated abstract] Infrared photodiodes fabricated in HgCdTe achieve near-ideal performance, however, in comparison with other semiconductors, processing techniques for HgCdTe are expensive and have relatively low yields. Reactive-ion-etching (RIE) in a H2⁄CH4 gas mixture, a process primarily used for material removal, will cause p-to-n type conversion in HgCdTe. It has been shown, by several groups, that infrared photodiodes fabricated with a process technology based on RIE p-to-n type-conversion achieve high yields with state-of-the-art performance. For this technology to be accepted RIE formed n-on-p photodiodes must demonstrate junction stability under normal operating conditions. Along with a stable junction, a compatible passivation technology that is able to withstand processing and operation temperatures is required. This thesis investigates the RIE p-to-n type-conversion mechanism in HgCdTe with the aim of demonstrating bake stable RIE formed junctions, and gaining an insight to the processes by which RIE type-conversion occurs. In pursuing these aims, two complimentary objectives were required, namely, the development of a passivation technology compatible with RIE formed junctions, and the development of a detailed I-V/Rd-V model for HgCdTe photodiodes. As a result of these objectives, this thesis presents a double-layer ZnS on CdTe passivation technology with which stable RIE-formed n-on-p junctions in HgCdTe are demonstrated. Using this process technology, mid-wave infrared (MWIR) HgCdTe photodiodes have been fabricated and subjected to a bake in vacuum at 80°C for 175 hours, after which there is negligible degradation in the zero-bias Dynamic-Resistance Area product (RoA) from the pre-bake values
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White, John Kenion. "Mid-wave infrared HgCdTe photodiode technology based on plasma induced p-to-n type conversion /." Connect to this title, 2005. http://theses.library.uwa.edu.au/adt-WU2005.0128.
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Reason, Joseph P. "A comparative study of nuclear technology and direct energy conversion methods for space power systems." Monterey, California. Naval Postgraduate School, 1997. http://hdl.handle.net/10945/8110.
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The objectives of this thesis are to investigate the theory of direct energy conversion, research the development of space nuclear power systems, evaluate the status of current systems, and draw conclusions about the feasibility and merit of using nuclear power for future space missions. Development of the earliest systems began in 1955 with the Systems for Nuclear Auxiliary Power (SNAP) Program and Project Rover. A detailed review of system design and performance is provided for the reactors and radioisotope thermoelectric generators (RTG's) of past and current programs. Thermoelectric and thermionic energy conversion techniques have been used predominantly in space nuclear power systems. The theory of these direct energy conversion methods is analyzed. Also, the safety review procedures and regulations governing the launch of nuclear sources into space are characterized. Conclusions compare accomplished levels of system performance to theoretically predicted limits and comment on the usefulness of space nuclear power for space applications
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Jingxi, Estella Zandile. "Forward osmosis : a desalination technology for the textile industry." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2674.
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Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2017.Similar to the energy crisis, the critical state of the water supply in South Africa (SA) is a combination of (i) resource exhaustion and pollution; (ii) increasing demand; and (iii) poor infrastructure. Despite its importance, water is the most poorly managed resource in the world. The disposal of industrial effluents contributes greatly to the poor quality of water. The textile industry consumes great quantities of water and produces enormous volumes of wastewater which requires appropriate treatment before being released into the environment. In an attempt to address the water issues, research globally has focused on advanced technologies such as desalination to increase limited pure water resources. The need for alternative desalination methods for the production of clean water from alternative water resources, such as seawater and brackish water, has gained worldwide attention. Reverse osmosis (RO) and Nanofiltration (NF) have been used as unswerving approaches to yield freshwater. Forward osmosis (FO) is a developing membrane technology that has increased substantial attention as a possible lower-energy desalination technology. However, challenges such as suitable FO membranes, membrane fouling, concentration polarisation, and the availability of effective draw solutions (DS), limit FO technology. FO is seeking more importance in novel areas where separation and recovery of the DS is not required. The aims of this study was to: i) identify alternative water resources and evaluate their potential as suitable feed solution (FS); ii) Identify dyes and evaluate their potential as suitable draw solutions (DS) at different concentrations; iii) assess the use of aquaporin biomimetic membrane and iv) assess a FO system for the production of dye solutions. Osmotic pressure (OP) is the pressure exerted by the flow of water through semi-permeable membrane, separating two solutions with different concentrations of solute. The DS should always have OP higher than the FS in order to achieve high water flux. Three basic dyes (i.e. Maxilon Turquoise, Red and Blue) and three reactive dyes (i.e. Carmine, Olive Green and Black) were selected, based on their common use in the SA textile industry. The respective dye samples were prepared at different concentrations and dye-to-salt mass ratios ranging from 1:10 to 1:60 and assessed for OP using a freezing point osmometer. A lab-scale FO unit was used for all the studies. Feed and draw channels were circulated in a counter-current flow at a volumetric flow rate of 600 mL/min. Feed solutions(FS) included deionised water (DI) as a control, brackish water (BW), synthetic seawater (SSW) and textile wastewater (TWW) collected from two textile factories. OP of the FS (DI, BW5, SSW and SW, Factory 1 and Factory 2) was 0, 414, 2761, 2579, 1505 and 3308 kPa, respectively. Basic Blue and Reactive Black generated a higher OP compared to other selected dyes in the study and were therefore selected to be used as DS at a 1:10 dye-to-salt ratio and 0.02 M concentration. An aquaporin biomimetic FO membrane (Aquaporin, Denmark) was used for all the experiments conducted in the FO mode.
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Zoric, I. "Multiple three-phase induction generators for wind energy conversion systems." Thesis, Liverpool John Moores University, 2018. http://researchonline.ljmu.ac.uk/8387/.
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During the past decade, there has been a considerable increase in the number of published works on multiphase machines and drives. This increased interest has been largely driven by a need for the so-called green energy, i.e. energy generated from renewable sources such as wind, and also an increased emphasis on greener means for transportation. Some of the advantages multiphase machines offer over three-phase counterparts are better fault tolerance, smaller current and power per phase, and higher frequency torque ripple. This thesis examines use of a multiphase induction generator in wind energy conversion systems (WECS). In particular, multiphase generators that comprise multiple 3-phase winding sets, where each winding set is supplied using an independent 3-phase voltage source inverter (VSI), are studied. It is claimed that these topologies offer advantages in cases where a WECS is connected to a multitude of independent ac or dc microgrids, systems where a single high-voltage dc link is needed or where a simple fault tolerance is achieved when a complete winding set is switched off. All of these examples require an arbitrary power or current sharing between winding sets. In order to achieve arbitrary current and power sharing, the control can be implemented using multi stator (MS) variables, so that the flux and torque producing currents of each winding set can be arbitrarily set. As an alternative, this thesis uses vector space decomposition (VSD) to implement the control, while individual winding set flux/torque producing currents are governed by finding the relationships between MS and VSD variables. This approach has all the advantages of both MS and VSD, i.e. access to individual winding set variables of MS and the ability to implement control in the multiple decoupled two dimensional subspaces of VSD, while heavy cross coupling between winding set variables, a weakness of MS, is avoided. Since the goal of the thesis is to present use of multiphase machines in WECS, modelling and simulation of a simple multiphase WECS in back-to-back configuration has been performed at first. All systems relevant to machine control where considered, such as grid and machine side VSIs, grid filter, indirect rotor field oriented control, current control in both flux/torque producing and non-producing subspaces, low order harmonic elimination, maximum power point tracking control, and voltage oriented control of the grid side VSI. Moreover, various WECS supply topologies were considered where developed current and power sharing would be a necessary requirement. Development of the proposed current sharing control commences with an analysis of multiple 3-phase machine modelling in terms of both MS and VSD variables. Since the actual control is implemented using decoupled VSD variables, VSD modelling has been studied in detail, resulting in an algorithm for creation of the VSD matrix applicable to any symmetrical or asymmetrical multiphase machine with single or multiple neutral points. Developed algorithm always decouples the machine into orthogonal two-dimensional subspaces and zero sequence components while making sure that all odd-order harmonics are uniquely mapped. Harmonic mapping analysis is offered as well. Next, relationship between MS and VSD variables has been developed by mapping MS variables into VSD subspaces. Since VSD matrix creation algorithm is valid for any multiphase machine, relationship between MS and VSD variables is applicable to any multiple 3-phase machine regardless of the configuration (symmetrical/asymmetrical), number of neutral points or machine type (synchronous or induction). Established relationship between MS and VSD has been used to implement current sharing control in decoupled VSD subspaces of the machine. It is shown that in order to achieve arbitrary current sharing it is only necessary to impose currents in flux/torque non-producing subspaces. Hence, total machine’s flux and torque are not affected at all. Besides verification by Matlab simulations, two topologies are experimentally investigated, a parallel machine side converter configuration and the case when a single high voltage dc link is created by cascading dc-links of the machine side VSIs. In the first case the ability of arbitrary current sharing between winding sets is validated, while the second tested topology demonstrates use of the developed control for the purpose of voltage balancing of the cascaded dc links.
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Reid, Patrick Earl Fitzgerald. "The integration of solid oxide fuel cell technology with industrial power generation systems." Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/18947.
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Jones, Gavin Wesley. "Distribution system operation and planning in the presence of distributed generation technology." Diss., Rolla, Mo. : University of Missouri-Rolla, 2007. http://scholarsmine.umr.edu/thesis/pdf/Jones_09007dcc803b193d.pdf.
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Thesis (M.S.)--University of Missouri--Rolla, 2007.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed November 16, 2007) Includes bibliographical references (p. 71-74).
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Thomas, Karin. "Low Speed Energy Conversion from Marine Currents." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8400.
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Afzal, Muhammad. "Nanocomposite Materials for New Energy Conversion Device." Thesis, KTH, Materialvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-122675.
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This thesis gives an approach how to develop newperovskite and nanocomposite cathode material for low temperature solid oxidefuel cells on the basis of nanocomposite approach to lower the operatingtemperature of SOFC. BaxCa1-xCoyFe1-yO3-δ(BCCF) and BSCF perovskite or nanocomposite oxides have been synthesized andinvestigated as catalytically potential cathode materials for low temperaturesolid oxide fuel cells (LTSOFC). Some single component materials have been alsosynthesized for new energy conversion device or EFFC. These nanocomposite andperovskite electrical conductors were synthesized by wet chemical, sol gel,co-precipitation and solid state reaction methods. Comparison with that ofcommercial Ba0.5Sr0.5Co0.8Fe0.2O3-δ(BSCF) cathode material, BCCF and locally prepared BSCF exhibit higher electricalconductivities as compared to that of commercial BSCF at same setup andconditions. In particular, novel Ba0.3Ca0.7Co0.8Fe0.2O3-δhas shown the maximum conductivity of 143 S/cm in air and local BSCF withconductivity of 313 S/cm in air at 550°C were measured by DC 4 probe method. Anadditional positive aspect of BCCF is that it is cost effective and works atroom temperature but with small output which will lead SOFC to operate atextremely low temperatures. XRD patterns of the samples reveal perovskite andnanocomposite structures of the said materials. Microstructure studies give thehomogeneous structure and morphology of the nanoparticles by using HighResolution Scanning Electron Microscopy (SEM). Cell resistance has beendetermined by Electrochemical Impedance Spectroscopy (EIS). Devised materialshave shown very good mechanical strength and stability proving their importancein advanced fuel cell technology. Power density of devices from 126 to 192 mWcm-2hasbeen achieved.
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Kozanoglu, Duygu. "Power Conversion Efficiency Enhancement Of Organic Solar Cells By Addition Of Gold Nanoparticles." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614702/index.pdf.
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In the first part of the study, power conversion efficiency enhancement of organic solar cells by addition of gold nanorods and gold nanostars into PEDOT: PSS (Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate)) layer was investigated. Efficiency of each sample set has been characterized by measuring current density-voltage characteristics. The best efficiencies obtained during this study are 2.88 % and 2.54 % by addition of gold nanostars and nanorods, respectively. The increase in PCEs is notable when these values are compared with the ones (1.67 %) obtained with a reference device which is prepared without adding any gold nanoparticles under the same conditions.
In the second part of the study, branched gold nanoparticles were succesfully grown directly on different types of surfaces such as glass, silicon wafer, and indium-tin-oxide (ITO) coated glass with a simple solution-based method in order to utilize them for further applications.
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Powell, Rick, and Chris Fitzsimmons. "INTELLIGENT DATA ACQUISITION TECHNOLOGY." International Foundation for Telemetering, 1997. http://hdl.handle.net/10150/607551.
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International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, NevadaTelemetry & Instrumentation, in conjunction with NASA’s Kennedy Space Center, has developed a commercial, intelligent, data acquisition module that performs all functions associated with acquiring and digitizing a transducer measurement. These functions include transducer excitation, signal gain and anti-aliasing filtering, A/D conversion, linearization and digital filtering, and sample rate decimation. The functions are programmable and are set up from information stored in a local Transducer Electronic Data Sheet (TEDS). In addition, the module performs continuous self-calibration and self-test to maintain 0.01% accuracy over its entire operating temperature range for periods of one year without manual recalibration. The module operates in conjunction with a VME-based data acquisition system.
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Todeschini, Grazia. "Wind Energy Conversion Systems based on DFIG Technology used as Active Filters: Steady-State and Transient Analysis." Digital WPI, 2010. https://digitalcommons.wpi.edu/etd-dissertations/97.
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This thesis deals with the performance of a Wind Energy Conversion System operating as a power generator and Active Filter simultaneously. As a power generator, the Wind Energy Conversion System converts wind energy into electric energy; as an Active Filter, it sinks the harmonic currents injected by Non-Linear Loads connected at the same feeder. Three control systems are developed to ensure the described operation; a specific study regarding the compensation of the triplen harmonics is carried out; Doubly-Fed Induction Generator derating is defined; and an engineering economic analysis is performed to determine the profitability of the proposed operation. The Wind Energy Conversion System performance as generator and Active Filter has been studied for steady-state analysis, fast transients and low transients. It is concluded that the proposed control systems allow operating the Wind Energy Conversion System as power generator and harmonic compensator both during steady state and transient operation; the described operation causes power loss increase and voltage distortion that determine the choice of the component and require system derating.
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Guerrero, Felipe Martinez. "Development of a wave energy basin to maximize wave energy conversion." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/20241.
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Swash, Mohammad Rafiq. "Holoscopic 3D imaging and display technology : camera/processing/display." Thesis, Brunel University, 2013. http://bura.brunel.ac.uk/handle/2438/11916.
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Holoscopic 3D imaging “Integral imaging” was first proposed by Lippmann in 1908. It has become an attractive technique for creating full colour 3D scene that exists in space. It promotes a single camera aperture for recording spatial information of a real scene and it uses a regularly spaced microlens arrays to simulate the principle of Fly’s eye technique, which creates physical duplicates of light field “true 3D-imaging technique”. While stereoscopic and multiview 3D imaging systems which simulate human eye technique are widely available in the commercial market, holoscopic 3D imaging technology is still in the research phase. The aim of this research is to investigate spatial resolution of holoscopic 3D imaging and display technology, which includes holoscopic 3D camera, processing and display. Smart microlens array architecture is proposed that doubles spatial resolution of holoscopic 3D camera horizontally by trading horizontal and vertical resolutions. In particular, it overcomes unbalanced pixel aspect ratio of unidirectional holoscopic 3D images. In addition, omnidirectional holoscopic 3D computer graphics rendering techniques are proposed that simplify the rendering complexity and facilitate holoscopic 3D content generation. Holoscopic 3D image stitching algorithm is proposed that widens overall viewing angle of holoscopic 3D camera aperture and pre-processing of holoscopic 3D image filters are proposed for spatial data alignment and 3D image data processing. In addition, Dynamic hyperlinker tool is developed that offers interactive holoscopic 3D video content search-ability and browse-ability. Novel pixel mapping techniques are proposed that improves spatial resolution and visual definition in space. For instance, 4D-DSPM enhances 3D pixels per inch from 44 3D-PPIs to 176 3D-PPIs horizontally and achieves spatial resolution of 1365 × 384 3D-Pixels whereas the traditional spatial resolution is 341 × 1536 3D-Pixels. In addition distributed pixel mapping is proposed that improves quality of holoscopic 3D scene in space by creating RGB-colour channel elemental images.
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Tu, Qingshi. "Fats, Oils and Greases to Biodiesel: Technology Development and Sustainability Assessment." University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1448037796.
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Renström, Ida. "Evaluation of autostereoscopic 3Dvideo for short-term exposure : produced using semiautomatic stereo-to-multiview conversion." Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-161885.
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Ida Renström Evaluation of autostereoscopic 3D video for short-term exposure, produced using semiautomatic stereo-to-multiview conversion ABSTRACT In this study, I investigate semiautomatic conversion from stereoscopic 3D to autostereoscopic 3D with multiple views. The conversion simplifies the production compared to creating autostereoscopic 3D from scratch. The research question of this study is; what level of holistic experience can be achieved from converted 3D compared to stereoscopic 3D video with glasses? The intended 3D contexts for this study require or are favored by glassesfree 3D with multiple views, and the exposure of 3D is shorttermed. I conducted user tests in a controlled setting as well as a public setting. The results show that it is difficult to make a general evaluation of the user experience of the final product, because different individuals perceive 3D very differently. Results from experiments in a controlled setting, where stereoscopic 3D was used as a direct reference, indicate that converted autostereoscopic 3D does not achieve the same perceived video quality as stereoscopic 3D. However, the fact that no glasses are needed compensates for this in the overall user experience. In an experiment with a public setting, where the participants' previous experiences of stereoscopic 3D were used as reference, a majority perceived the quality of converted autostereoscopic 3D to be better than, or equivalent to, that of previous experiences with stereoscopic 3D. A majority also said that the experience was positive. The latter experience made u se of an environment and situation that was close to real life and the intended types of contexts. Therefore, these results argue that autostereoscopic multiview 3D video converted from stereoscopic 3D is useful and gives a good holistic experience compared to stereoscopic 3D with glasses. This is in contexts favored by glassesfree 3D with multiple views and where the exposure of 3D is shorttermed. An autostereoscopic display in a retail space, where people walk by and view advertised material for a few seconds, is one example of a context suited for converted autostereoscopic 3D.Ida Renström Evaluering av autostereoskopisk 3D-video för korttidsexponering, producerad genom semiautomatisk stereo-till-multiview konvertering SAMMANFATTNING I denna studie undersöker jag semiautomatisk konvertering från stereoskopisk 3D till autostereoskopisk 3D med multipla vyer. Konverteringen förenklar produktionen, jämfört med att skapa autostereoskopisk 3D från grunden. Frågeställningen i denna studie är; vilken helhetsupplevelse resultatet av konverteringen ger i jämförelse med stereoskopisk 3D, inom vissa specifika användningsområden. Dessa användningsområden utgörs av 3D-sammanhang som starkt gynnas av glasögonfri 3D med multipla vyer och där exponeringen av 3D är kortvarig. Jag genomförde användartester i dels kontrollerad miljö samt offentlig miljö. Resultaten i denna studie visar att det är svårt att göra en generell utvärdering av användarupplevelsen av de resultat som denna konverteringsmetod ger, eftersom 3D upplevs väldigt olika av olika individer. Experimenten i kontrollerad miljö, där stereoskopisk 3D användes som direkt referens, visar att konverterad autostereoskopisk 3D håller en lägre upplevd kvalité än stereoskopisk 3D. Det faktum att inte glasögon behövs kompenserar dock för detta när man ser till den totala upplevelsen och de krav som situationen ställer. Vid det offentliga experimentet, med deltagarnas tidigare erfarenheter av stereoskopisk 3D som referens, ansåg en majoritet att den upplevda kvalitén av konverterad autostereoskopisk 3D var bättre än eller lika bra som tidigare erfarenheter av stereoskopisk 3D. Det senare experimentet genomfördes i en miljö och ett sammanhang som var mer likt verkligheten och det tänkta sammanhanget än det tidigare. Därför väger dessa resultat tungt och argumenterar för att autostereoskopisk 3D video med multipla vyer konverterad från stereoskopisk 3D är användbar och ger en bra helhetsupplevelse, inom användningsområden som starkt gynnas av glasögonfri 3D med multipla vyer och där exponeringen av 3D är kortvarig. Ett konkret exempel på detta kan vara att folk passerar en autostereskopisk skärm på en offentlig plats och möter reklam i 3D under några sekunder.
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Perera, Dehiwalage Harshani Nimalika. "Thin film composite membranes for desalination." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709429.
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Nguyen, Thuyen Huu Manh. "A photovoltaic detector technology based on plasma-induced p-to-n type conversion of long wavelength infrared HgCdTe." University of Western Australia. School of Electrical, Electronic and Computer Engineering, 2005. http://theses.library.uwa.edu.au/adt-WU2005.0098.
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[Truncated abstract] HgCdTe is the leading semiconductor material for the fabrication of high performance infrared photon detectors, in particular, for detection of radiation beyond the near infrared. State-of-the-art infrared detection and imaging systems are currently based around high density focal plane arrays consisting of HgCdTe photodiodes as detector elements. Despite the high performance of HgCdTe infrared detectors, and the many benefits they can offer to industry and society, their utilisation remains limited due to the high cost of production. The chemical composition and narrow bandgap of the HgCdTe material used for infrared detection means that the material is inherently very susceptible to defect formation caused by the processing procedures required for device fabrication. Consequently, fabrication of HgCdTe photodiode arrays have traditionally been characterised by low yields and high costs for arrays that meet required operability specifications. In this thesis a new photodiode fabrication technology with the potential to improve device yields over traditional fabrication technologies is presented. This new fabrication technology is distinguished from others by the use of plasma-induced p-to-n type conversion of HgCdTe for junction formation. This allows great simplification of the fabrication process and avoids high temperature processing during and after junction formation, and keeps the junction protected from the atmosphere at all stages of fabrication. The development of the photodiode fabrication technology using plasma-induced junction formation has involved characterising the electrical transport properties of the type-converted layers, fabrication and characterisation of photodiodes, and photodiode dark current modelling
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Renström, Ida. "Evaluation of autostereoscopic 3D video for short-term exposure : produced using semiautomatic stereo-to-multiview conversion." Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-159188.
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Nishiyama, Takashi. "Swords into plowshares civilian application of wartime military technology in modern Japan, 1945-1964 /." Connect to this title online, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1104324814.
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Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains xiv, 246 p.; also includes graphics (some col.) Includes bibliographical references (p. 212-242).
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Pensupa, Nattha. "The development of a biological pretreatment strategy for the conversion of wheat straw to biofuels or platform chemicals." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/30407/.
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The increasing concern of energy shortage and environmental pollution attracts worldwide exploration of using sustainable biomaterials for the production of biofuels and biochemicals. Utilising lignocellulosic raw materials for valuable bio-products production is generally considered as a preferred biosynthetic technology. Although various processes have already been proposed, lignocellulose hydrolysis is still remaining as one of the major challenges that prevents wide spread application of lignocellulosic raw materials in biofuel and biochemical production. The aim of this study was to investigate the feasibility of applying soft-rot fungi as a biological pretreatment of wheat straw for the generation of cellulase enzymes and then use the freshly produced enzymes to hydrolyse the fermented wheat straw to a sugar rich hydrolysate. The wheat straw hydrolysate had also been examined for the production of bioethanol and biochemicals, such as succinic acid and itaconic acid. Solid State Fermentations (SSF) of wheat straw were carried out using both Aspergillus niger and Trichoderma reesei. The fermentation conditions, such as moistures content, culture time, addition of nutrients, and modification of wheat straw were optimised for the production of cellulase. In a SSF using autoclaved wheat straw, an enzyme activity of 9.5 FPU/g was achieved. When 0.5% yeast extract and mineral solution were added, the enzyme activities increased to 24.0 FPU/g after 5 days of cultivation. In a SSF of an alkali soaked wheat straw (wheat straw treated with 1% NaOH at 25˚C for 24 hours), 21.8 FPU/g was obtained after just 1-day culture. Optimisation of hydrolysis process led to a hydrolysate containing 59.8 g/L glucose, which was achieved from the hydrolysis of biologically pretreated wheat straw at 18% solid loading, with an enzyme loading rate of 55 FPU/g at 50˚C. Fermentations using the wheat straw hydrolysate resulted in 28.6 g/L ethanol, which was equivalent to 93.4% of theoretic yield. Utilisation of wheat straw hydrolysate for succinic acid production was investigated using recombinant yeast strains. For Saccharomyces cerevisiae D2, the deletion of SDH1 and SDH2 genes enhanced succinic acid production by 68%. Optimisation of fermentation conditions and fermentation scales led to a succinic acid production to around 12 g/L, which was nearly 100-folds of what succinic acid production using the wild S. cerevisiae D2 strain at initial fermentation conditions. Use wheat straw hydrolysate to replace commercial glucose based semi-defined medium resulted in the same succinic acid production yield, but lower concentration due to the low sugar concentration in the hydrolysate. Biosynthesis of itaconic acid using wheat straw hydrolysate was also explored, but no significant itaconic acid production was observed.
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Luo, Siwei. "Conversion of Carbonaceous Fuel to Electricity, Hydrogen, and Chemicals via Chemical Looping Technology - Reaction Kinetics and Bench-Scale Demonstration." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1397573499.
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