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Прибудько, Роман Михайлович. "Компенсатор реактивної потужності в перехідних режимах." Master's thesis, Київ, 2018. https://ela.kpi.ua/handle/123456789/25613.
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В представленій роботі було розроблено компенсатор длякомпенсації реактивної потужності в перехідних режимах. На основі аналізу, узагальнення й систематизації наукових джерел висвітлено огляд основних способів компенсації реактивної потужності. Оцінюються переваги та недоліки окремих видів компенсації. Розглянуто методи компенсації для різних типів перехідних процесів.
Числові розрахунки та моделювання проводились з використанням програмних засобів MATLAB (пакет Simulink), MathCAD. Результатом роботи є розроблена модель пристрою компенсації реактивної потужності в перехідних режимах. Оцінено підвищення коефіцієнту потужності при використанні запропонованого алгоритму компенсації.
Запропонований алгоритм компенсації в перехідних режимах дозволяє покращити параметри якості електроенергії мінімум на 5%.
Результат роботи може бути використаний при розробці пристроїв компенсації в усталених і перехідних режимах.In the present thesis project was developed compensator for the compensation of reactive power in transient conditions. Based on the analysis, synthesis and systematization of scientific sources, an overview of the main methods of reactive power compensation is highlighted. The advantages and disadvantages of certain types of compensation are assessed. Compensation methods for various types of transient processes are considered. Numerical calculations and modeling were carried out using software tools MATLAB (Simulink package), MathCAD. The result of the work is a developed model of a device for reactive power compensation in transient conditions. Estimated increase in power factor when using the proposed compensation algorithm. The proposed compensation algorithm in transient conditions allows to improve the quality parameters of electricity by at least 5%. The result of the work can be used in the development of compensation devices in established and transient modes.
В представленной работе был разработан компенсатор для компенсации реактивной мощности в переходных режимах. На основе анализа, обобщения и систематизации научных источников освещены обзор основных способов компенсации реактивной мощности. Оцениваются преимущества и недостатки отдельных видов компенсации. Рассмотрены методы компенсации для различных типов переходных процессов. Числовые расчеты и моделирование проводились с использованием программных средств MATLAB (пакет Simulink), MathCAD. Результатом работы является разработанная модель устройства компенсации реактивной мощности в переходных режимах. Оценен повышения коэффициента мощности при использовании предложенного алгоритма компенсации. Предложенный алгоритм компенсации в переходных режимах позволяет улучшить параметры качества электроэнергии минимум на 5%. Результат работы может быть использован при разработке устройств компенсации в устоявшихся и переходных режимах.
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Braxton, Shawn Lamont. "Examining Workplace Discrimination in a Discrimination-Free Environment." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/36381.
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The purpose of this study is to explore how racial and gender discrimination is reproduced in concrete workplace settings even when anti-discrimination policies are present, and to understand the various reactions utilized by those who commonly experience it. I have selected a particular medical center, henceforth referred to by a pseudonym, “The Bliley Medical Center” as my case study. In order to examine the gaps between the normative component instituted to regulate human behavior and the behavioral component in a workplace setting, I will employ critical race theory and feminist theories of intersectionality. The works of critics such as Delgado and Stefancic, Patricia Williams, and Patricia Hill Collins, among others, foreground the utility of storytelling as a means to 1) understand the gaps between formal policies and organizational behavior, 2) call attention to the experiential knowledge and evidence that is traditionally excluded in discrimination cases, and (3) to explain how formal anti-discrimination policies can actually be used to legitimize discrimination. Based on the results of this case study, we can conclude that an alternative interactionist, critical race, and intersectional approach is especially needed in terms of calling attention to traditionally ignored social processes that aid in the reproduction of workplace inequality in concrete workplace settings, thus expanding the current workplace discrimination scholarship.Master of Science
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Chang, Ian I. "Bubble compression and condensation in single component co-current downflow." Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/26223.
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In an investigation of the process termed hydraulic vapour compression (HVC), a photographic study of bubble compression and condensation rates in single component co-current downflow has been performed. Supplemental to the photographic study, measurements of the deliverable mass flowrates of the HVC process were also carried out.
The downward flow of a gas and liquid mixture, as occurs in the HVC process, results in the compression of the gas phase because of the increasing hydraulic pressure. Bubble compression heating provides the driving temperature difference for both heat and mass transfer to occur. The minimization of the transfer processes is desirable to ensure a high compression efficiency.
Experiments were carried out using near saturated Freon-11 in a 2.54 cm I.D., 1.7 m long glass downcomer. Bubbles were filmed during travel along the downcomer. Histories of the decrease in individual bubble size were determined from silhouette traces obtained from sequenced single frames selected from the exposed films. Bubble volumes and surface areas were inferred by numerically revolving digitized images of the traces about their principal centroidal axes. The inferred volumes and surface areas provided the basis upon which heat and mass transfer rates were calculated. Delivered vapour mass flowrates were measured by hot film anemometry.
Results showed that mass condensation rates increased along the length of the downcomer. Local external Nusselt numbers used to characterize the transfer processes at the bubble wall, ranged from 0.1 to 16. The deliverable mass flowrates achieved by the HVC process were found to be comparable to those produced by the well known process of hydraulic air compression.Applied Science, Faculty of
Mechanical Engineering, Department of
Graduate
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Oberc, Timothy James. "Reliability of lead-free high temperature surface mount component attaches." College Park, Md.: University of Maryland, 2008. http://hdl.handle.net/1903/8987.
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Thesis (M.S.) -- University of Maryland, College Park, 2008.Thesis research directed by: Dept. of Mechanical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Ersoz, Ali. "Magnetic Resonance Current Density Imaging Using One Component Of Magnetic Flux Density." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612164/index.pdf.
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Magnetic Resonance Electrical Impedance Tomography (MREIT) algorithms using current density distribution have been proposed in the literature. The current density distribution can be determined by using Magnetic Resonance Current Density Imaging (MRCDI) technique. In MRCDI technique, all three components of magnetic flux density should be measured. Hence, object should be rotated inside the magnet which is not trivial even for small size objects and remains as a strong limitation to clinical applicability of the technique. In this thesis, 2D MRCDI problem is investigated in detail and an analytical relation is found between Bz, Jx and Jy. This study makes it easy to understand the behavior of Bz due to changes in Jx and Jy. Furthermore, a novel 2D MRCDI reconstruction algorithm using one component of B is proposed. Iterative FT-MRCDI algorithm is also implemented. The algorithms are tested with simulation and experimental models. In simulations, error in the reconstructed current density changes between 0.27% - 23.00% using the proposed algorithm and 7.41% - 37.45% using the iterative FT-MRCDI algorithm for various SNR levels. The proposed algorithm is superior to the iterative FT-MRCDI algorithm in reconstruction time comparison. In experimental models, the classical MRCDI algorithm has the best reconstruction performance when the algorithms are compared by evaluating the reconstructed current density images perceptually. However, the J-substitution algorithm reconstructs the best conductivity image by using J obtained from the proposed algorithm. Finally, the iterative FT-MRCDI algorithm shows the best performance when the reconstructed current density images are verified by using divergence theorem.
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Zaporozhchenko, A., S. A. Nepijko, and G. Schonhense. "Influence of alternating low voltage component on field photoemission current forma semiconductor tip." Thesis, Sumy State University, 2014. http://essuir.sumdu.edu.ua/handle/123456789/39931.
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In this work we considered the influence of low alternating voltage of up to 100 V on the field photoemission process from a semiconductor tip under high voltage of 0.7-5.0 kV and photon excitation of 1.3 eV energy.
Considered cathodes were made of high-resistivity silicon with p-type conductivity.
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Karshenas, Hamid Reza. "Input/output harmonic free current link three-phase AC power supply." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ28287.pdf.
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Noriega, Graciela Day. "North American free trade agreement and education as a component of sustainable development." Honors in the Major Thesis, University of Central Florida, 1998. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/46.
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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
Arts and Sciences
Political Science
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Pasquale, Anthony J. "Synthesis and Characterization of Multi-Component Polymeric Materials Prepared via Free Radical Polymerization." Diss., Virginia Tech, 2002. http://hdl.handle.net/10919/27251.
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High molecular weight star-shaped polystyrenes were prepared via the coupling of 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) terminated polystyrene oligomers with divinylbenzene (DVB) in m-xylene at 138 °C. Linear polystyrene oligomers (Mn = 19,300 g/mol, Mw/Mn = 1.10) were synthesized in bulk styrene using benzoyl peroxide in the presence of TEMPO at approximately 130 °C. In situ mid-infrared spectroscopy was successfully utilized to follow initiation, monomer conversion, and polymer formation. Real-time data allowed for the determination of apparent rate constants of 2.1E-5 s-1 at 132 °C and 1.2E-5 s-1 at 126 °C from the profile of the decaying styrene vinyl carbon-hydrogen (=CH2) absorbance at 907 cm-1. Coupling of the TEMPO terminated oligomers under optimum conditions resulted in a compact and dense product with a number average molecular weight exceeding 300,000 g/mol (Mw/Mn = 3.03) after 24 h, suggesting the formation of relatively well-defined star-shaped polymers.
Synthetic factors that affected the molecular weight, yield, and composition of maleic anhydride (MAH), norbornene (Nb), and tert-butyl 5-norbornene-2-carboxylate (NbTBE) terpolymers were investigated. Pseudo first order kinetic analysis using in situ FTIR indicated that the observed rate of reaction was a strong function of the Nb/NbTBE ratio with a maximum of 6.7E-5 s-1 for a 50/0/50 Nb/NbTBE/MAH monomer ratio and a minimum of 1.1E-5 s-1 for a 0/50/50 Nb/NbTBE/MAH ratio. Polymer yields were also observed to be a function of the Nb/NbTBE ratio and also decreased with increasing NbTBE. Calculated work of adhesion values (Wadh) values were observed to increase as the content of NbTBE was increased. 193 nm photoresist formulations incorporating polymers with high NbTBE content showed increased imaging performance using 193 nm light and successfully produced sharp and defined features as small as 110 nm, which was demonstrated via scanning electron microscopy (SEM). Additional functionality was introduced via the copolymerization of MAH with several norbornene (Nb) derivatives that were synthesized from facile Diels-Alder cycloaddition reactions of cyclopentadiene with a-olefins containing electron withdrawing groups. Subsequent hydrolysis of the anhydride offered further versatility and provided an avenue to introduce aqueous base solubility into Nb/MAH copolymers.Ph. D.
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Carlsson, Hampus, and Kärrman Marcus. "Cloud-based Mobile System for Free-Living Gait Analysis : System component : Server architecture." Thesis, Högskolan i Halmstad, Akademin för informationsteknologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-34293.
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Progress in the fields of wearable sensor technologies together with specialized analysis algorithms has enabled systems for gait analysis outside labs. An example of a wearable sensor is the accelerometer embedded in a typical smartphone. The goal was to propose a system design capable of hosting existing gait analysis algorithms in a cloud environment, and tailor the design as to deliver fast results with the ambition of reaching near real-time. The project identified a set of enabling technologies by examining existing systems for gait analysis; the technologies included cloud computing and WebSockets. The final system design is a hierarchical composition starting with a Linux VM running Node.js, which in turn connects to a database and hosts instances of the MatLab runtime. The results show the feasibility of mobile cloud based free-living gait analysis. The architectural design provides a solution to the critical problem of enabling existing algorithms to run in a cloud environment; and shows how the graphical output of the native algorithm could be accurately reproduced in a web browser. The system can process a chunk of 1300 data points under 3 seconds for a client streaming at 128 Hz, while simultaneously streaming the real time signal.
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Jia, Jin [Verfasser], Stephan [Akademischer Betreuer] Frei, and Frank [Gutachter] Jenau. "Current scan methods to predict radiated emissions of automotive components according to CISPR 25 / Jin Jia. Betreuer: Stephan Frei. Gutachter: Frank Jenau." Dortmund : Universitätsbibliothek Dortmund, 2015. http://d-nb.info/1101606584/34.
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Berba, Farag Hussein Bahri. "Minimisation of output DC current component in grid-connected inverters for solar power applications." Thesis, University of Newcastle Upon Tyne, 2012. http://hdl.handle.net/10443/1548.
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In grid-connected photovoltaic applications, a supply-frequency output transformer is normally used to isolate the inverter from the supply. This transformer is heavy, costly and adds to the overall power loss. However removal of the output transformer can result in unwanted DC components appearing in the inverter output current. Excessive DC current injection into the distribution network can affect distribution components as well as other loads connected to the network. There are various circuits which can be used to for grid connection without the use of an output transformer. These include the 2-level half-bridge and the H-bridge inverters. These circuits have the disadvantage of the requirement for higher rated power devices or increased EMI problems due to high frequency switching of the DC-link relative to earth. To overcome these problems, a three-level half-bridge inverter circuit is used, where the DC-link voltage can be twice the device voltage rating allowing the use low rated switching devices. The neutral conductor is connected to the mid-point of a split rail supply from PV array, and therefore the DC-link voltage is not switching relative to earth. The aim of this research is to minimise the DC current component in the output of a grid-connected inverter when a supply-frequency output transformer is not used. A three-level diode-clamped half-bridge inverter is proposed to interface the PV panel directly to the utility grid. The main contribution of this research lies in the development of an auto-calibration technique for the DC-link current sensors in the multi-level inverter. Combined with a current feedback control scheme this technique allows the minimisation of DC current offset drift in the Hall-Effect current sensors. Auto-calibrated DC-link current sensors in turn allow the inverter output current controller to minimise the output DC current component in spite of sensor drift and other disturbances. A comprehensive review on the different types of grid-connected PV systems, the problems caused by DC current injection into the grid, and up-to-date techniques to overcome this problem is included. The performance of the auto-calibration technique is investigated using both computer simulation and an experimental test rig.
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Boonumpaichaikul, Tossapon, and Unnada Mongkoltada. "Future of Thai Electronic Component Industry under ACFTA." Thesis, Mälardalen University, Mälardalen University, Mälardalen University, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-10046.
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Explore factors that influence investors interested in investing in the electronic components sector in Thailand, with a focus on the consequences of Thailand‟s membership in the ASEAN-China Free Trade Agreement.
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Gonzales, Fuentes Lee. "HELPING COGNITIVE RADIO IN THE SEARCH FOR FREE SPACE." Thesis, Högskolan i Gävle, Avdelningen för elektronik, matematik och naturvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-11495.
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Spectrum sensing is an essential pre-processing step of cognitive radio technology for dynamic radio spectrum management. One of the main functions of Cognitive radios is to detect the unused spectrum and share it without harmful interference with other users. The detection of signal components present within a determined frequency band is an important requirement of any sensing technique. Most methods are restricted to the detection of the spectral lines. However, these methods may not comply with the needs imposed by practical applications. This master thesis work presents a novel method to detect significant spectral components in measured non-flat spectra by classifying them in two groups: signal and noise frequency lines. The algorithm based on Fisher’s discriminant analysis, aside from the detection of spectral lines, estimates the magnitude of the spectral lines and provides a measure of the quality of classification to determine if a spectral line was incorrectly classified. Furthermore, the frequency lines with higher probability of misclassification are regrouped and the validation process recomputed, which results in lower probabilities of misclassification. The proposed automatic detection algorithm requires no user interaction since any prior knowledge about the measured signal and the noise power is needed. The presence or absence of a signal regardless of the shape of the spectrum can be detected. Hence, this method becomes a strong basis for high-quality operation mode of cognitive radios. Simulation and measurement results prove the advantages of the presented technique. The performance of the technique is evaluated for different signal-to-noise ratios (SNR) ranging from 0 to -21dB as required by the IEEE standard for smart radios. The method is compared with previous signal detection methods.
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Tynngård, Nahreen. "Free oscillation rheometry in the assessment of platelet quality /." Linköping : Linköping University, Department of Clinical and Experimental Medicine, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11525.
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Laplante, Marc. "A Java(TM)-based model for multi-component free-radical bulk and solution polymerizations." Thesis, University of Ottawa (Canada), 2004. http://hdl.handle.net/10393/26686.
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Modelling and simulation play an essential role in developing, optimizing and understanding the steps involved in the production of polymers. A simulator was designed in order to model free-radical bulk and solution homopolymerizations, as well as multi-component polymerizations. Several optional models were incorporated in to the simulator, such as several glass transition temperature models, and the penultimate model. Java(TM) was selected as the programming language because of its object-oriented nature, providing high flexibility and ensuring easy extension of the code. Once the simulator was validated against experimental data and another simulator, it was used to model three systems: butyl acrylate/vinyl acetate (BA/VAc), styrene/butyl acrylate (Sty/BA), and butyl acrylate/methyl methacrylate/vinyl acetate (BA/MMA/VAc). (Abstract shortened by UMI.)
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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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Hannon, Fay. "A high average-current electron source for the Jefferson Laboratory free electron laser." Thesis, Lancaster University, 2008. http://eprints.lancs.ac.uk/76588/.
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The spectral output power from the Jefferson Laboratory infra-red free electron laser is primarily limited by the performance of the electron injector. Free electron laser power is directly proportional to the electron beam current and at present the electron injector is limited to 10mA average current. To date the highest laser power achieved has been 14.2kW and the next goal is to reach 100kW. For this to occur a new electron injector has been designed that is capable of producing over 100mA average current. This thesis describes an investigation into the behaviour of this injector through simulation. Given that the layout of the injector is fixed, this thesis aims to find suitable operating regimes for various electron bunch charge scenarios. By determining the important features the electron beam must have at the exit of the injector, and the limitations of each component, this information was used to form an optimisation problem that could be solved to find the best operation point. To improve the simulation of electron bunches being launched from a photocathode, measurements were performed on a similar injector to evaluate the thermal energy and response time of the cathode. These values are a function of the laser wavelength used with the photocathode and so were repeated over a range of wavelengths from infra-red to green. The injector at Cornell University was used to take measurements of the electron beam that could then be compared against simulation to benchmark the code. The brightness and quality of electron beams in linac-based light sources, such as at Jefferson Laboratory, are limited by the properties of the beam in the injector. It is therefore important to have knowledge of the phase space distribution of the electron beam in addition to the rms emittance, to provide an insight into high brightness formation mechanisms. A tomography technique has been successfully used to reconstruct the transverse phase space of the electron beam delivered from the Cornell University ERL DC gun. The gun is similar to that in the 100mA JLab injector, therefore a tomography diagnostic could in future be applied to that case.
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Taube, Matilda, and Karl Stenlund. "Functionalized capillaries for label- free bio-molecule-detection utilizing the streaming current method." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-206081.
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This report aims to make a contribution in optimizing a bio-sensor which exploits the changes in streaming current in a fused silica capillary as target molecules bind to immobilized receptors on the inner surface of the capillary. In this study we investigate the temporal characteristics of the sensor response as a function of capillary-dimension for different concentrations of target biomolecules. Using Heceptine-z domain interaction pairs and silica capillaries with different inner diameters in the range of 25-55 µm and lengthin the range of 3-9 cm we show that the reduction in capillary cross-section re-sults in a faster sensor response. The results show qualitative agreement withan analytical model grounded on diffusion-based mass transport under laminar flow condition and offer possibility to achieve a lower limit of detection with thinner capillaries.Denna rapport bidrar i arbetet att optimera en biosensor baserad på den flödes-inducerade elektriska strömmen som uppstår i en glaskapillär där målmolekyler i en lösning binder till immobiliserade receptorer på den inre ytan av kapillären. I experimenten som här presenteras har tidsberoendet hos sen-sorsvaret undersökts för olika koncentrationer av målmolekylen, från 10 nm till 1 nm. Interaktionsparet (Immuglobin 1G och antikropp)(Heceptine-z) användes i dessa experiment och med att testa olika glaskapillärer med innerdiametrar i intervallet 25 till 55 µm, samt längd mellan 3 och 9 cm, visar vi att en minskning av innerdiametern resulterar i snabbare sensorsvar. Resultaten visar påen kvalitativ överrenstämmelse med en analytisk modell grundad i diffusionsbaserad masstransport med krav på laminärt flöde. Denna modell tyder på att det är möjligt att detektera lägre koncentrationen med tunnare kapillärer än vad här har testats.
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Madaan, Sushant. "Comprehensive Study of Single component electrolyte-free fuel cell: Joint solar cell and fuel cell mechanism." Thesis, KTH, Kraft- och värmeteknologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-149742.
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Figueiredo, Michael. "Reference-free high-speed cmos pipeline analog-to-digital converters." Doctoral thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/8776.
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Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Electrical and Computer Engineering of the Faculdade de Ciências e Tecnologia of Universidade Nova de LisboaMore and more signal processing is being transferred to the digital domain to profit from the technological enhancement of digital circuits. Where technology scaling enhances the capabilities of digital circuits, it degrades the performance of analog circuits. However, it is important to note that the impact that technology scaling has on digital circuits is becoming smaller and smaller, which means that, in nanotechnologies, to enhance energy and area efficiency, we can not simply depend on the benefits of this scaling. Although, a share of the efficiency can be obtained from the technology, new circuit architectures and techniques have to be developed to really push the limits of efficiency. In data converters, more specifically analog-to-digital converters (ADCs), a decision can be made: research energy and area efficient analog circuit techniques and architectures that cope with technological scaling issues, or design algorithms that use digital circuitry to assist the poor analog technological performance. The former option is the premise for the work developed in this thesis. The work reported in this thesis explores various design techniques with the purpose of enhancing the power and area efficiency of building blocks mainly to be used in multiplying digital-to-analog converter based ADCs. Therefore, novel analog techniques are developed for the three main blocks of an MDAC-based stage, namely, the flash quantizer, the amplifier, and the switched capacitor network of the MDAC. These techniques include self-biasing and inverter-based design for the flash quantizer and amplifier. Regarding the MDAC, it combines three techniques: unity feedback factor, insensitivity to capacitor mismatch, and current-mode reference shifting. In the second part of this work, the designed amplifier is implemented and experimentally characterized demonstrating its practical feasibility and performance. The final part of this work explores the design and implementation of a medium-low resolution high speed pipeline ADC incorporating all the developed circuits. Experimental results validate the feasibility of the techniques and demonstrate the attractiveness in terms of power dissipation and reduced area.
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La, Chicuong. "Modulation of L-type Ca²§+ current by free intracellular Mg²§+ in guinea pig ventricular myocytes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/NQ66673.pdf.
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Vijayaraghavan, Iyengar Anupama. "Independent component analysis of spontaneous laminar specific current sources and sinks in area S1 of the rat brain." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=114505.
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The laminar structure of the neocortex is universal. In spite of some variation in structure and cell type, the composition of the 6 cortical laminae is conserved in virtually all neocortical areas and amongst all mammalian species. However, the function of cortical layers remains largely unknown. Here we seek to determine whether laminar-specific spontaneous current sources and sinks are distributed randomly, or whether they show repeating patterns. We further aim to investigate whether the time-course of current sources and sinks can be decomposed into separate independent components.To this end, we recorded Local Field Potentials (LFPs) from a linear array of equally spaced electrodes positioned locally perpendicular to the cortical manifold in rat somatosensory area S1Fl. The frequency-band specific Current Source Density (CSD) was derived from the filtered LFPs, which warded off the effects of volume conduction and resulted in reference independent signals. Principal Component Analysis (PCA) was applied to the CSD data in order to reduce dimensionality and noise, and to perform whitening. Temporal Independent Component Analysis (ICA) was then applied to each of the frequency-band specific CSD with reduced dimensions using the FastICA methods. The column vectors of the mixing matrix represent the spatial weights or 'strength of neural activation' across cortical layers, associated with each independent component. We tested the repeatability and reliability of the pattern of laminar activity across the cortex.The results show patterns of laminar-specific dipoles of current sources and sinks that are repeatable across sessions/subjects. Across most of the frequency bands, the maximum contribution towards the signal power is from layers 4, 5a and 5b. The cortical depth of dipoles depends on the frequency band. In the delta (1-4 Hz) band, a prominent dipole was observed in layer 6. In the theta (5-8 Hz) and alpha (9-14 Hz) bands, repeating dipoles overlap with layers 4, 5a and 5b. In the beta (15-30 Hz) band, a dipole was observed in layers 5a and 5b. In the low and high gamma bands (30-50 and 50-100 Hz, respectively), prominent dipoles overlapped with layer 3 and 4. Our findings suggest that spontaneous current sources and sinks emerge in a non-random, laminar and frequency-band specific manner, showing independent components that are consistent across runs and animals. We hypothesize that these independent components reflect separate contributions of thalamo-cortical input and of spontaneous activity of cortical origin.La structure laminaire du neocortex est universelle. Au-delà de petites variations dans la structure et la composition cellulaire, l`organisation des 6 couches corticales est conservé à travers tout les mammifères. Pourtant, la fonction des différentes couches corticales est largement inconnue. Ici, nous examinons si les sources et puits de courent observés durant làctivité neuronale spontanée sont distribués de façon aléatoire dans les couches corticales ou si des motifs reproductibles peuvent être observé. Pour examiner cette question, nous avons enregistré des potentiels de champs locaux (LFP) avec une électrode linéaire positionnée perpendiculaire à la surface corticale de làire S1Fl du cortex somato-sensoriel du rat. Afin d`éliminer l`impact de la référence électrique commune, la densité de sources de courent (CSD) a été calculé à partir des LFP. De plus, le CSD a été filtré dans les bandes classiques de EEG. Ensuite, afin de réduire la dimensionnalité des données, lànalyse des composantes principales (PCA) a été appliqué. Finalement, les composantes temporelles indépendantes (tICA) ont été calculées pour chaque bande de fréquence en utilisant làlgorithme FastICA. La reproductibilité du motif laminaire fût testée pour chaque composante.Nos résultats suggèrent des motifs laminaires de dipôles de source de curent qui sont reproductible à travers les différentes sessions et sujets. Pour la majorité des bandes de fréquence, la contribution maximale à l`énergie du signal vient des couches 4, 5a et 5b. La profondeur des dipôles dépend de la bande de fréquence. Dans la bande delta (1-4 Hz), le dipôle majeur est situé dans la couche 6. Dans la bande theta (5-8 Hz) et alpha (9-14 Hz), les dipôles reproductibles sont situés dans les couches 4, 5a et 5b. Dans la bande beta (15-30 Hz) un dipôle a été observé dans les couches 5a et 5b. Finalement, dans la bande gamma (30- 50 et 50-100 Hz), le dipôle majeur est situé dans les couches 3 et 4.Nos résultats suggèrent que les sources et puits de curent observées durant làctivité neuronale spontanée présentes de motifs laminaires reproductibles et ne sont donc pas aléatoires. Nos supposons que ces composantes indépendantes reflètent des contributions séparées du thalamus et des autres régions corticales.
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Winter, Gordon H. "The effects of a klyston on a high-current, high-gain free electron laser at SLAC." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1995. http://handle.dtic.mil/100.2/ADA302820.
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Bourne, David. "Alternative dynamic impact testing : component screening of FMH-energy absorber safety plastic\2122." Thesis, University West, Department of Technology, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-833.
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Viljoen, Vernon. "Integration of a vision-guided robot into a reconfigurable component- handling platform." Thesis, [Bloemfontein?] : Central University of Technology, Free State, 2014. http://hdl.handle.net/11462/120.
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Thesis (M. Tech.) -- Central University of Technology, Free State, 2010The latest technological trend in manufacturing worldwide is automation. Reducing human labour by using robots to do the work is purely a business decision. The reasons for automating a plant include: Improving productivity Reducing labour and equipment costs Reducing product damage Monitoring system reliability Improving plant safety. The use of robots in the automation sector adds value to the production line because of their versatility. They can be programmed to follow specific paths when moving material from one point to another and their biggest advantage is that they can operate for twenty-four hours a day while delivering consistent quality and accuracy. Vision-Guided Robots (VGRs) are developed for many different applications and therefore many different combinations of VGR systems are available. All VGRs are equipped with vision sensors which are used to locate and inspect various objects. In this study a robot and a vision system were combined for a pick-and-place application. Research was done on the design of a robot for locating, inspecting and picking selected components from a moving conveyor system.
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Wilson, Fiona. "Equilibrium and stability properties of collisionless current sheet models." Thesis, University of St Andrews, 2013. http://hdl.handle.net/10023/3548.
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The work in this thesis focuses primarily on equilibrium and stability properties of collisionless current sheet models, in particular of the force-free Harris sheet model. A detailed investigation is carried out into the properties of the distribution function found by Harrison and Neukirch (Physical Review Letters 102, 135003, 2009) for the force-free Harris sheet, which is so far the only known nonlinear force-free Vlasov-Maxwell equilibrium. Exact conditions on the parameters of the distribution function are found, which show when it can be single or multi-peaked in two of the velocity space directions. This is important because it may have implications for the stability of the equilibrium. One major aim of this thesis is to find new force-free equilibrium distribution functions. By using a new method which is different from that of Harrison and Neukirch, it is possible to find a complete family of distribution functions for the force-free Harris sheet, which includes the Harrison and Neukirch distribution function (Physical Review Letters 102, 135003, 2009). Each member of this family has a different dependence on the particle energy, although the dependence on the canonical momenta remains the same. Three detailed analytical examples are presented. Other possibilities for finding further collisionless force-free equilibrium distribution functions have been explored, but were unsuccessful. The first linear stability analysis of the Harrison and Neukirch equilibrium distribution function is then carried out, concentrating on macroscopic instabilities, and considering two-dimensional perturbations only. The analysis is based on the technique of integration over unperturbed orbits. Similarly to the Harris sheet case (Nuovo Cimento, 23:115, 1962), this is only possible by using approximations to the exact orbits, which are unknown. Furthermore, the approximations for the Harris sheet case cannot be used for the force-free Harris sheet, and so new techniques have to be developed in order to make analytical progress. Full analytical expressions for the perturbed current density are derived but, for the sake of simplicity, only the long wavelength limit is investigated. The dependence of the stability on various equilibrium parameters is investigated.
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PEREZ, OSCAR HERNAN POLANCO. "DETERMINATION OF THE LONGITUDINAL COMPONENT OF ELETROMAGNETIC FIELSD PRODUCED BY SURFACE CURRENT DENSITIES, IN APPLICATIONS OF DIADIC GREENNULLS FUNCTION." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1998. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=8130@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICONeste trabalho desenvolve-se uma técnica para determinação da componente longitudinal do campo elétrico gerado por uma densidade superficial de corrente. A metodologia proposta baseia-se na diádica de Green da região em consideração, sendo estudadas regiões interiores em que existe uma solução analítica da equação de onda escalar em coordenadas ortogonais e regiões exteriores, em sistemas de coordenadas esféricas e cilíndricas. Para cada uma das soluções, mostra-se a convergência da expressão obtida para a componente longitudinal do campo elétrico, expressa por uma série ou integrais de funções modais. Baseado na metodologia desenvolvida, elabora-se um modelo de análise para determinação de campos e impedância característica em cabos coaxiais de seção arbitrária. O modelo é aplicado a cabos de seção circular e retangular. A metodologia de determinação de campos por diádicas de Green é ainda aplicada à análise de cabos coaxiais de seção retangular, com estais de fixação do condutor interno, localizados periodicamente.
It is developed a method for the determination of the longitudinal component of the electric field generated by a surface current density in the interior or the exterior regions. The proposed method is based on the dyadic Green´s function of the region under consideration, beeing analysed interior regions, assuming the knowledge of the analytical solution for the scalar wave equation in the orthogonal coordinate systems and external regions, using spherical and cylindrical coordinate systems. For the each solution, it is shown the convergence of the expression obtained for the longitudinal component of the electric field. Based on the developed method, a model of analysis is elaborated to determine the field and the characteristics impedance of coaxial cables of arbitrary cross section. The model is applied to cables with circular and rectangular sections. The dyadic Green´s function method is finally applied to the analysis of coaxial cables with internal metallic struts periodicaly placed.
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Jansen, van Nieuwenhuizen Rudolph Johannes. "Development of an automated robot vision component handling system." Thesis, Bloemfontein : Central University of Technology, Free State, 2013. http://hdl.handle.net/11462/213.
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Thesis (M. Tech. (Engineering: Electrical)) -- Central University of technology, Free State, 2013In the industry, automation is used to optimize production, improve product quality and increase profitability. By properly implementing automation systems, the risk of injury to workers can be minimized. Robots are used in many low-level tasks to perform repetitive, undesirable or dangerous work. Robots can perform a task with higher precision and accuracy to lower errors and waste of material. Machine Vision makes use of cameras, lighting and software to do visual inspections that a human would normally do. Machine Vision is useful in application where repeatability, high speed and accuracy are important. This study concentrates on the development of a dedicated robot vision system to automatically place components exiting from a conveyor system onto Automatic Guided Vehicles (AGV). A personal computer (PC) controls the automated system. Software modules were developed to do image processing for the Machine Vision system as well as software to control a Cartesian robot. These modules were integrated to work in a real-time system. The vision system is used to determine the parts‟ position and orientation. The orientation data are used to rotate a gripper and the position data are used by the Cartesian robot to position the gripper over the part. Hardware for the control of the gripper, pneumatics and safety systems were developed. The automated system‟s hardware was integrated by the use of the different communication protocols, namely DeviceNet (Cartesian robot), RS-232 (gripper) and Firewire (camera).
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Rahko, M. (Matti). "A qualification tool for component package feasibility in infrastructure products." Doctoral thesis, Oulun yliopisto, 2011. http://urn.fi/urn:isbn:9789514296819.
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Abstract The target of this dissertation is to propose a new qualification tool (QT) for component package (CP) feasibility qualification in telecommunication infrastructure products. The primary reason for the introduction of the QT is the Electrical and Electronic Equipment (EEE) manufacturers’ continuing development of new products with tighter product requirements, e.g. compact size, environmental friendliness and cost-efficiency. CP’s need to match these requirements and thus they need to be developed further and qualified/re-qualified continuously. This qualification process with the new component package needs to be done in as early phase as possible, enabling EEE manufacturers to implement component packages into use with minimal risk. Qualification of a CP to match with these requirements is usually done with the qualification expert’s possessed know-how. However, this process takes a lot of time as all the possible data must be collected or even created. Thus a new method needs to be introduced for early phase qualification. The QT proposed here contains eight qualification sub-areas for feasibility qualification of the CP and it uses three qualification principles. Including all these sub-areas to the feasibility qualification clearly enables more reliable and trustworthy conclusions. The QT is required as an assisting qualification tool for specialists and as a preliminary qualification tool, e.g. for hardware (HW) designers or component engineers. It could be used also as a requirement communication tool between customers and component package manufacturers. After the QT’s sub-areas and functionality were developed, functionality and approval limits were set-up with 44 different widely used commercial CPs. This historical data is recorded for future use in its own database. The QT is a unique tool as there are no competing open-source tools available in the market that can be tailored to match with the user’s own requirementsTiivistelmä Työn tarkoituksena oli esittää uusi kvalifiointityökalu (QT) infrastruktuurituotteiden komponenttikoteloiden käytettävyyden arviointiin. Laitevalmistajien kehittäessä uusia pienempiä, ympäristöystävällisempiä ja kustannustehokkaampia laitteita asettavat he samalla vastaavia vaatimuksia myös komponenttikoteloille. Vastaavasti komponenttien valmistajat joutuvat kehittämään komponentteja ottamalla käyttöön uusia materiaaleja ja kotelorakenteita ja kvalifioimaan niiden ominaisuuksia asiakkaiden vaatimuksien mukaisesti. Laitevalmistajien riski uusien komponenttikoteloiden käyttöönotossa pystytään minimoimaan, kun komponenttikoteloiden kvalifiointi tehdään mahdollisimman aikaisessa vaiheessa. Kvalifioinnit tehdään yleensä kvalifiointiasiantuntijoiden tietotaidon perusteella. Tämä prosessi on kuitenkin perinteisesti hidas, joten nopeammalle arviointimenetelmälle on selkeä tarve. Työssä kehitettyyn kvalifiointityökaluun määritettiin kahdeksan arviointialuetta. Lisäksi sitä voidaan käyttää kolmella eri kvalifiontiperiaatteella. Näiden arviointialueiden huomioiminen kvalifiointiprosessin aikana parantaa selkeästi tuloksen luotettavuutta ja todenmukaisuutta. Työkalu on määritetty siten, että sitä voivat käyttää asiantuntijat avustavana kvalifiointityökaluna sekä suunnittelijat / komponentti-insinöörit alustavana kvalifiointityökaluna. Lisäksi sitä voidaan myös käyttää asiakasvaatimusten määrityksessä ja tiedonvälityksessä asiakkaan ja toimittajan välillä. QT:n kvalifiointialueiden määrittelyn ja toiminnallisuuden rakentamisen jälkeen, hyväksyntäkriteerit tutkittiin ja arvioitiin käyttäen 44 erilaista kaupallista komponenttikoteloa työkalun lopullisen hienosäädön tekemiseksi. Koska kvalifioinnin tiedot tallennetaan QT:n tietokantaan, pystyy laitevalmistajat hyödyntämään aikaisemmat historiatiedot tulevissa kvalifioinneissa. QT on ennen näkemätön työkalu, sillä markkinoilla ei ole vastaavia avoimen lähdekoodin kvalifiointityökaluja tarjolla, jota voidaan räätälöidä asiakkaan omien tarpeiden mukaisesti
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Bin, Hasan M. M. A. "Current based condition monitoring of electromechanical systems : model-free drive system current monitoring : faults detection and diagnosis through statistical features extraction and support vector machines classification." Thesis, University of Bradford, 2012. http://hdl.handle.net/10454/5732.
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A non-invasive, on-line method for detection of mechanical (rotor, bearings eccentricity) and stator winding faults in a 3-phase induction motors from observation of motor line current supply input. The main aim is to avoid the consequence of unexpected failure of critical equipment which results in extended process shutdown, costly machinery repair, and health and safety problems. This thesis looks into the possibility of utilizing machine learning techniques in the field of condition monitoring of electromechanical systems. Induction motors are chosen as an example for such application. Electrical motors play a vital role in our everyday life. Induction motors are kept in operation through monitoring its condition in a continuous manner in order to minimise their off times. The author proposes a model free sensor-less monitoring system, where the only monitored signal is the input to the induction motor. The thesis considers different methods available in literature for condition monitoring of induction motors and adopts a simple solution that is based on monitoring of the motor current. The method proposed use the feature extraction and Support Vector Machines (SVM) to set the limits for healthy and faulty data based on the statistical methods. After an extensive overview of the related literature and studies, the motor which is the virtual sensor in the drive system is analysed by considering its construction and principle of operation. The mathematical model of the motor is used for analysing the system. This is followed by laboratory testing of healthy motors and comparing their output signals with those of the same motors after being intentionally failed, concluding with the development of a full monitoring system. Finally, a monitoring system is proposed that can detect the presence of a fault in the monitored machine and diagnose the fault type and severity
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Almeida, Fernando Mattavo de. "Numerical simulation of the flow through an aqxial tidal-current turbine employing an elastic-free-surface approach." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/3/3135/tde-18092018-074509/.
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Together with the world economic growth is the increasing of energy generation demand. However, the upgrade of world power production capability could affect the environment negatively. Even the clean and renewable sources, such as hydroelectricity and wind powers have socio-economic and environmental disadvantages. For example, the required flooded area for a hydro power plant construction could devastate entire forests, and the installation of a wind farm power plant could affect migratory rotes of birds and generate high levels of noise. Hence, for the balancing of advantages and disadvantages of each power generation source, it is necessary to diversify, which requires investments in new power sources. In this context, the energy generation in the ocean is highlighted. The first point concerning the ocean energy is that there is no need of population removal from the installation area, such as the onshore based methods and the second point is that most of the population is concentrated in coastal areas. Therefore the production occurs near to the demand, decreasing the costs with energy distribution. The two main methodologies for harassing energy from oceans are based on gravity waves and in tides. And since the tidal cycles are governed mainly by the gravitational interaction between oceans, Moon and Sun, they are easily predictable, which increases the reliability of such systems. These works explores methodologies to analyse the power generation from a single axial tidal current turbine through a Steady State RANS methodology. Are discussed the effects of flow directionality, inlet velocity profile and turbulence levels and the results are compared with an experimental scheme. It is proposed an alternative methodology for free surface modelling in the CFD analysis. The usual methodology, VOF, it is based on a homogeneous, biphasic approach which requires an additional mesh refinement and is computationally expensive. This new methodology introduces an elastic wall approach in the free surface region in which the stiffness is calculated to provide the same restoring effect as gravity. In general, the results for open domain matched with the experimental results, validating the numerical model and the confined domain has shown a higher power and thrust coefficients if compared with the open domain, which is in accordance with the actuator disk theory approach. The elastic free surface presented convergence problems related to high Froude numbers and therefore to high deformations. However, a simulation with 10% of the original inlet velocity was performed, achieving reasonable results for both power and thrust coefficients evaluation.O crescimento econômico mundial e o aumento na demanda pela geração de energia andam juntos. No entanto, uma maior capacidade de produção de energia poderia afetar negativamente o meio ambiente. Mesmo as fontes limpas e renováveis, como a hidrelétrica e a eólica acarretam em impactos socioeconômicos e ambientais. Por exemplo, a construção de uma usina hidrelétrica demanda uma imensa área alagada que pode devastar florestas inteiras e a instalação de uma usina eólica pode afetar a migração de certas espécies de pássaros e produzir altos níveis de barulho. Portanto, para equilibrar as vantagens e desvantagens devidas a cada meio de produção de energia, é necessária a diversificação, que demanda de investimentos em novas fontes. Neste contexto, a geração de energia nos oceanos é destacada. O primeiro ponto a respeito desta fonte é de que não há a necessidade de remoção da população na área de instalação, tal como os métodos de geração dentro do continente. O segundo principal ponto é a respeito da distribuição de energia. A maior parte da população mundial vive em regiões costeiras, diminuindo, portanto, a distância entre a produção e demanda, reduzindo assim, seus custos. As duas principais metodologias para se explorar a energia proveniente dos oceanos são: Energia de Ondas e Energia de Marés. E considerando que os ciclos de mare são governados principalmente pela interação gravitacional entre os oceanos, lua e sol, eles são facilmente previsíveis, o que aumenta a confiabilidade dos sistemas de geração de energia baseados em marés. Este trabalho explora as metodologias para analisar a geração de energia a partir de uma única turbina axial de corrente de maré através de uma metodologia baseada nas equações de Navier-Stokes com a média de Reynolds, analisadas em regime permanente. São discutidos efeitos da direção do escoamento, perfil de velocidades na entrada e nos níveis de turbulência. Os resultados são comparados com experimentos. É proposta uma metodologia alternativa para a modelagem da superfície livre com CFD uma vez que a metodologia atual é baseada em um escoamento bifásico que demanda de um refinamento adicional da malha e é computacionalmente caro. A nova metodologia usa uma parede elástica na região da superfície livre com a rigidez ajustada para se obter o mesmo efeito de restauração que a gravidade. De maneira geral, os resultados para o domínio aberto se aproximaram dos resultados experimentais, validando o modelo numérico e além disso, o modelo considerando confinamento da turbine mostrou maiores valores para os coeficientes de potência e empuxo, estando portanto, de acordo com a teoria do disco atuador. O modelo com a superfície livre elástica apresentou problemas de convergência, relacionados com números de Froude elevados, uma vez que isto se relaciona com maiores deformações na região da superfície livre. Uma simulação com 10% da velocidade original foi realizada, obtendo-se resultados coerentes para ambos coeficientes de potência e empuxo.
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McKenzie, Catherine. "Sustainable development, urban transport and urban theory : current positions, convergence and contradictions; a case study of transport and environmental policy-making in selected European cities." Thesis, Lancaster University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286984.
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Lash, Dominic. "Metonymy as a creative structural principle in the work of J.H. Prynne, Derek Bailey and Helmut Lachenmann with a creative component." Thesis, Brunel University, 2010. http://bura.brunel.ac.uk/handle/2438/4668.
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This thesis takes the linguistic concept of metonymy and examines its potential as a creative structural principle both in poetry and in music. I explore the role of metonymy in the work of the poet J.H. Prynne, the improvising guitarist Derek Bailey, and the composer Helmut Lachenmann. I have also deployed some of the ideas arising from this exploration in a modular composition for improvisers entitled Representations, recordings of which accompany this thesis. My argument is that metonymy provides a means by which a work of poetry or of music can be highly sensitive to the world which it inhabits, but can do so by itself being an inextricably linked part of this world, rather than an attempt to reproduce or represent it, or to simply pass judgement from the sidelines. In my introduction I outline the literary theory of metonymy. I discuss the way that metonymy encompasses relationships both of contiguity and causality, and make the case that the many limitations inherent in metonymy (which have often led to its being perceived as inferior to metaphor) can in fact be seen as advantanges, because of the way that they can bind the work of art to the real. I briefly discuss some previous applications of metonymy to music, and outline an understanding of musical metonymy based on linear dissimilarity, historical and social contiguity, the origins and agency behind particular sounds, and an occlusion of the structural middleground. The first chapter discusses the work of J.H. Prynne. I argue that a use of metonymy as a productive constraint is illuminated by a philosophical position according to which the world is known to be real because of the resistances it presents to the actualisation of our desires. I discuss the role of metonymy in the development of Prynne’s poetic oeuvre, before illustrating my argument with a detailed analysis of the 2001 sequence Unanswering Rational Shore. In the second chapter I turn to the work of Derek Bailey. Drawing heavily on unpublished items from the Incus archive, I demonstrate the meticulous way in which Bailey constructed his improvisational vocabulary, and the senses in which that vocabulary and its deployment could be characterised as metonymic. I explore the influence on Bailey of Stockhausen, Beckett and Musil, and show how form and material in his work are inextricably entwined. The third chapter examines the work of Helmut Lachenmann and in particular the 1992 composition „... zwei Gefühle ...“, Musik mit Leonardo. I examine the role of the listener and the productive activity that metonymic structures require of them. I focus on Lachenmann’s deployment both of actual and pseudo-causality in his music, as well as his use of historical reference in an indexical fashion. In my fourth chapter I present my composition for improvisers, Representations. I discuss its mechanics, development, and influences, and I set forth its relationship to the concepts of musical metonymy I have elucidated in the body of this thesis, under the headings of “arbitration”, similarity, referentiality and the relationship between material and the middleground. In a short concluding chapter I take another angle on the links between the themes of this thesis by discussing the role of rubbish in the work of Prynne, Bailey and Lachenmann, and its apparently paradoxical relationship with a certain concept of purity. This allows me to conclude by considering the relationship of metonymic structures to a conception of truth which, I believe, has a certain urgency in the contemporary artistic climate.
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Braml, Martin [Verfasser], and Gabriel [Akademischer Betreuer] Felbermayr. "On current account discrepancies, tariff retaliation, and the political economy of free trade / Martin Braml ; Betreuer: Gabriel Felbermayr." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2020. http://d-nb.info/1215500017/34.
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Shaheed, Rawaa. "3D Numerical Modelling of Secondary Current in Shallow River Bends and Confluences." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34922.
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Secondary currents are one of the important features that characterize flow in river bends and confluences. Fluid particles follow a helical path instead of moving nearly parallel to the axis of the channel. The local imbalance between the vertically varying centrifugal force and the cross-stream pressure gradient results in generating the secondary flow and raising a typical motion of the helical flow. A number of studies, including experimental or mathematical, have been conducted to examine flow characteristics in curved open channels, river meanders, or confluences. In this research, the influence of secondary currents is studied on the elevation of water surface and the hydraulic structures in channel bends and confluences by employing a 3D OpenFOAM numerical model.
The research implements the 3D OpenFOAM numerical model to simulate the horizontal distribution of the flow in curved rivers. In addition, the progress in unraveling and understanding the bend dynamics is considered. The finite volume method in (OpenFOAM) software is used to simulate and examine the behavior of secondary current in channel bends and confluences. Thereafter, a comparison between the experimental data and a numerical model is conducted. Two sets of experimental data are used; the data provided by Rozovskii (1961) for sharply curved channel, and the dataset provided by Shumate (1998) for confluent channel.
Two solvers in (OpenFOAM) software were selected to solve the problem regarding the experiment; InterFoam and PisoFoam. The InterFoam is a transient solver for incompressible flow that is used with open channel flow and Free Surface Model. The PisoFoam is a transient solver for incompressible flow that is used with closed channel flow and Rigid-Lid Model. Various turbulence models (i.e. Standard k-ε, Realizable k-ε, LRR, and LES) are applied in the numerical model to assess the accuracy of turbulence models in predicting the behaviour of the flow in channel bends and confluences. The accuracies of various turbulence models are examined and discussed.
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El, Kouchni Samira. "Towards an Animal-Derived Component Free Medium for Sp2/0 Fed-batch Culture : requirements and Challenges for an Effective Lipid Supplementation." Thesis, Bordeaux 2, 2011. http://www.theses.fr/2011BOR21891.
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Les anticorps monoclonaux (mAb) sont d’importants agents thérapeutiques largement utilisés dans le traitement de cancers. Ces protéines recombinantes complexes sont généralement produites dans des lignées cellulaires de mammifères et l’industrie pharmaceutique a développé des procédés robustes permettant d’obtenir de grandes quantités d’anticorps monoclonaux de qualité constante. Une tendance générale observée aujourd’hui est d’éviter l’utilisation de produits d’origine animale dans ces procédés. En effet, ces composés représentent un risque de contamination du médicament par des agents infectieux et les autorités règlementaires renforcent leurs exigences pour leur retrait des procédés de fabrication. Ces composés sont par ailleurs mal définis et posent des problèmes de variabilité des procédés de production. L’objectif de ce projet était de développer un milieu sans dérivés animaux pour la culture d’une lignée cellulaire Sp2/0 utilisée par la société Merck Serono pour exprimer un anticorps monoclonal thérapeutique. Le procédé de fabrication actuel contient de la sérum albumine bovine (BSA) et de l’EX-CYTE (concentré commercial de lipoprotéines et acides gras) extraits de sérum bovin. Le retrait des deux composés du milieu de culture a entrainé une diminution de la productivité du procédé de 87% et il a été observé que l’EX-CYTE et la BSA étaient essentiels pour la survie de notre lignée cellulaire Sp2/0. La BSA a permis à elle seule de remplacer l’EX-CYTE dans le procédé et a été utilisée comme modèle pour le développement d’un remplacement sans dérivés animaux. Une étude de caractérisation de la préparation de BSA a été effectuée afin d’identifier les facteurs responsables de son activité promotrice pour la croissance cellulaire. Les lipides représentaient une partie importante de cette activité mais un rôle significatif d’autres protéines contaminantes a été révélé. Enfin, un supplément lipidique sans dérivés animaux a été développé. Ce supplément était constitué d’un mélange de quatre acides gras (les acides oléique, linoléique, palmitique et stéarique) couplés à de la sérum albumine humaine recombinante (rHSA). Le supplément acides gras-rHSA a permis de remplacer l’EX-CYTE et la BSA et un milieu sans composés d’origine animale a finalement été obtenuMonoclonal antibodies (mAbs) are important therapeutics widely used for cancer therapy. Mammalian cell lines are usually employed to produce these complex recombinant proteins and the pharmaceutical industry has developed robust processes that deliver large quantities of mAbs with a sustained quality. A general trend observed today is to avoid the use of animal-derived components in such processes. Indeed, these compounds represent a potential risk of contamination of the final drug product with infectious agents and regulatory authorities are putting pressure for their removal from manufacturing processes. Such compounds are also ill defined and source of variability for the production processes. The goal of this project was to develop an animal-derived component free (ADCF) medium for the culture of an Sp2/0 cell line used by the company Merck Serono to express a therapeutic mAb. The manufacturing process currently used contains bovine serum albumin (BSA) and EX-CYTE (a commercial concentrate of lipoproteins and fatty acids) sourced from bovine serum. The removal of both components from the cell culture medium decreased the productivity of the process by 87%. EX-CYTE and BSA were found to be essential for the survival of our Sp2/0 cell line. BSA, which was found to replace EX-CYTE in the process, was used as a model for the development of an animal-derived component free replacement. A characterization of the BSA preparation was carried out to identify the factors responsible for its growth-promoting activity. Lipids accounted for a major part of the activity of the BSA preparation but a significant role of other protein contaminants was revealed. Finally, an animal-derived component free lipid supplement was developed. This supplement consisted in a mixture of four fatty acids (FA) (oleic, linoleic, palmitic and stearic acids) complexed with recombinant human serum albumin (rHSA). The FA/rHSA supplement could substitute for EX-CYTE and BSA and an ADCF medium was finally obtained
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Harrison, Michael George. "Equilibrium and dynamics of collisionless current sheets." Thesis, St Andrews, 2009. http://hdl.handle.net/10023/705.
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Sneary, Adrian Bernard. "The fabrication of a high temperature superconducting magnet and critical current characterisation of the component Bi₂Sr₂Ca₂Cu₃Oₓ tapes and filaments in high magnetic fields." Thesis, Durham University, 2000. http://etheses.dur.ac.uk/4517/.
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The transport critical current density (J(_c)) of a 37 filament Bi-2223/Ag tape has been measured as a function of field and temperature from 4.2 K up to 90 K. Data have been obtained over a large current range from 10 mA up to 100 A and in fields up to 23 T with the tape in 3 orientations with respect to field. These comprehensive data have been used to test the predictions of the flux creep and weak link models used to explain J(_c) in Bi-2223 tapes. The J(_c)(B,T) dependence of optimised Bi-2223 tapes has been calculated using a curved film model. The model assumes perfect grain connectivity and that the local superconducting properties are equivalent to those in the best reported thin films. A comparison between the calculations and measured J(_c)(B,T) dependencies suggest that in high fields at 20 K, J(_c) in presently available industrially processed tapes is only a factor of 8 below the performance of ideal fully optimised tapes. Transport measurements have been made on Bi-2223 single filaments extracted from an alloy sheathed multifilamentary tape in liquid nitrogen at 77 K in fields up to 300 mT with the field aligned parallel and perpendicular to the a-b planes. Further Jc(B,T) data have been taken in a variable temperature insert at temperatures between 60 to 90 K in fields up to 15 T. In a study of the electric field-current density {E-J) characteristics of the c-axis orientated data at 77 K, negative curvature is observed in traces below 280 mT. However, the 280 mT trace exhibits both positive and negative curvature in different current regimes in contrast to the predictions of standard theory. A laboratory scale Bi-2223 superconducting magnet producing a maximum field of 1.29 T at 4.2 K has been designed and fabricated. The magnet comprises 6 resin impregnated double wound pancakes with a 40 mm bore fabricated via the react and wind route. Critical current density measurements have been made as a function of magnetic field, angle and strain at 4.2 K and 77 K on short samples of the constituent tape. The E-J characteristics of all component coils have been measured and a comparison with short sample data shows that minimal additional damage occurred beyond that produced by the bending strain on the tape and the long length variation in J(_c). Sufficient detail is provided for the non-specialist to assess the potential use of brittle superconducting tapes for magnet technology and construct a laboratory scale magnet.
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Xin, Bai. "Numerical simulation of a marine current turbine in turbulent flow." Thesis, Queen Mary, University of London, 2014. http://qmro.qmul.ac.uk/xmlui/handle/123456789/7900.
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The marine current turbine (MCT) is an exciting proposition for the extraction of renewable tidal and marine current power. However, the numerical prediction of the performance of the MCT is difficult due to its complex geometry, the surrounding turbulent flow and the free surface. The main purpose of this research is to develop a computational tool for the simulation of a MCT in turbulent flow and in this thesis, the author has modified a 3D Large Eddy Simulation (LES) numerical code to simulate a three blade MCT under a variety of operating conditions based on the Immersed Boundary Method (IBM) and the Conservative Level Set Method (CLS). The interaction between the solid structure and surrounding fluid is modelled by the immersed boundary method, which the author modified to handle the complex geometrical conditions. The conservative free surface (CLS) scheme was implemented in the original Cgles code to capture the free surface effect. A series of simulations of turbulent flow in an open channel with different slope conditions were conducted using the modified free surface code. Supercritical flow with Froude number up to 1.94 was simulated and a decrease of the integral constant in the law of the wall has been noticed which matches well with the experimental data. Further simulations of the marine current turbine in turbulent flow have been carried out for different operating conditions and good match with experimental data was observed for all flow conditions. The effect of waves on the performance of the turbine was also investigated and it has been noticed that this existence will increase the power performance of the turbine due to the increase of free stream velocity.
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Ibrahim, Ahmad. "Development of photoinitiating systems for free radical Photopolymerization usable for laser Imaging." Thesis, Mulhouse, 2011. http://www.theses.fr/2011MULH4082.
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Le sujet de thèse sur lequel je travaille depuis trois ans est l’étude et le développement des systèmes photoamorceurs pour des applications holographiques. Ce travail a lieu en collaboration avec l’équipe BMS (Bayer Material Science) de Bayer-Leverkusen (Allemagne). Mes études se sont limitées aux systèmes utilisables avec une source d’irradiation appartenant à la partie visible du spectre électromagnétique de la lumière (400 nm – 700 nm).Parmi les différents types des réactions de polymérisation, nous avons choisi la polymérisation radicalaire. L’étape cruciale dans cette réaction réside dans la génération des radicaux qui amorcent la réaction. Ces derniers sont formés par transformation, via absorption de lumière, d’un composé photosensible. La formation de ces espèces est en général en compétition avec plusieurs processus de désactivation. Les polymérisations radicalaires sont en particulier fortement inhibées par l’oxygène de l’air. Pour réduire l’effet de l’oxygène et pour avoir des conditions comparables à ceux appliqués dans l’industrie, nos échantillons ont été préparés en utilisant la technique laminée (l’échantillon est mis entre deux films de polypropylène). [...]The subject of the thesis I have been working on for three years is the study and development of photoinitiating systems for holographic applications. This work takes place in collaboration with the BMS (Bayer Material Science) team from Bayer Leverkusen (Germany). My studies have been limited to systems used with a radiation source belonging to the visible part of the electromagnetic spectrum of light (400 nm - 700 nm). Among the different types of polymerization reactions, we chose the radical polymerization. The critical step in this reaction is the generation of radicals which initiate the reaction. These are formed by transformation via absorption of light of a photosensitive compound. The formation of these species is generally in competition with several deactivation process. [...]
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Valkoun, Petr. "Proudy ve středních vodičích napájecích sítí a jejich důsledky." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217595.
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This work deals with an origin of the harmonic currents, their classification into symmetrical components and their influence on neutral conductor in distribution systems. It analyses the heat strain increase in distribution cables and distortion of supply tension in consequence of harmonic zero component flows in distribution system and it provides possibilities of neutral conductor overload and break-in protection.
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Wong, William Chiu-Kit. "CFD Flame Spread Model Validation: Multi-Component Data Set Framework." Digital WPI, 2012. https://digitalcommons.wpi.edu/etd-theses/918.
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"Review of the literature shows that the reported correlation between predictions and experimental data of flame spread vary greatly. The discrepancies displayed by the models are generally attributed to inaccurate input parameters, user effects, and inadequacy of the model. In most experiments, the metric to which the model is deemed accurate is based on the prediction of the heat release rate, but flame spread is a highly complex phenomenon that should not be simplified as such. Moreover, fire growth models are usually made up of distinctive groups of calculation on separate physical phenomena to predict processes that drive fire growth. Inaccuracies of any of these “sub-models” will impact the overall flame spread prediction, hence identifying the sources of error and sensitivity of the subroutines may aid in the development of more accurate models. Combating this issue required that the phenomenon of flame spread be decomposed into four components to be studied separately: turbulent fluid dynamics, flame temperature, flame heat transfer, and condensed phase pyrolysis. Under this framework, aspects of a CFD model may be validated individually and cohesively. However, a lack of comprehensive datasets in the literature hampered this process. Hence, three progressively more complex sets of experiments, from free plume fires to fires against an inert wall to combustible wall fires, were conducted in order to obtain a variety of measurements related to the four inter-related components of flame spread. Multiple permutations of the tests using different source fuels, burner size, and source fire heat release rate allowed a large amount of comparable data to be collected for validation of different fire configurations. FDS simulations using mostly default parameters were executed and compared against the experimental data, but found to be inaccurate. Parametric study of the FDS software shows that there are little definitive trends in the correlation between changes in the predicted quantities and the modeling parameters. This highlights the intricate relationships shared between the subroutines utilized by FDS for calculations related to the four components of flame spread. This reveals a need to examine the underlying calculation methods and source code utilized in FDS."
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Bothma, Bernardus Christian. "Performance and reliability optimisation of a data acquisition and logging system in an integrated component-handling environment." Thesis, Bloemfontein : Central University of Technology, Free State, 2011. http://hdl.handle.net/11462/14.
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McCauley, Neil K. "Producing a background free data set for measurement of the charge current flux and day-night asymmetry at the Sudbury Neutrino Observatory." Thesis, University of Oxford, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270284.
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LU, Zhibo. "Blockade of Slow Component of the Delayed Rectifier K^+ Current (I_) Prolonged Action Potential Duration (APD) without Increasing Dispersion between Ventricles(RIEM Conference II, 2002)." Research Institute of Environmental Medicine, Nagoya University, 2002. http://hdl.handle.net/2237/2807.
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Angulo, Barrios Carlos. "Gallium arsenide based buried heterostructure laser diodes with aluminium-free semi-insulating materials regrowth." Doctoral thesis, KTH, Microelectronics and Information Technology, IMIT, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3305.
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Semiconductor lasers based on gallium arsenide and relatedmaterials are widely used in applications such as opticalcommunication systems, sensing, compact disc players, distancemeasurement, etc. The performance of these lasers can beimproved using a buried heterostructure offering lateralcarrier and optical confinement. In particular, if theconfinement (burying) layer is implemented by epitaxialregrowth of an appropriate aluminium-free semi-insulating (SI)material, passivation of etched surfaces, reduced tendency tooxidation, low capacitance and integration feasibility areadditional advantages.
The major impediment in the fabrication of GaAs/AlGaAsburied-heterostructure lasers is the spontaneous oxidation ofaluminium on the etched walls of the structure. Al-oxide actsas a mask and makes the regrowth process extremely challenging.In this work, a HCl gas-basedin-situcleaning technique is employed successfully toremove Al-oxide prior to regrowth of SI-GaInP:Fe and SI-GaAs:Fearound Al-containing laser mesas by Hydride Vapour PhaseEpitaxy. Excellent regrowth interfaces, without voids, areobtained, even around AlAs layers. Consequences of usinginadequate cleaning treatments are also presented. Regrowthmorphology aspects are discussed in terms of different growthmechanisms.
Time-resolved photoluminescence characterisation indicates auniform Fe trap distribution throughout the regrown GaInP:Fe.Scanning capacitance microscopy measurements demonstrate thesemi-insulating nature of the regrown GaInP:Fe layer. Thepresence of EL2 defects in regrown GaAs:Fe makes more difficultthe interpretation of the characterisation results in the nearvicinity of the laser mesa.
GaAs/AlGaAs buried-heterostructure lasers, both in-planelasers and vertical-cavity surface-emitting lasers, withGaInP:Fe as burying layer are demonstrated for the first time.The lasers exhibit good performance demonstrating thatSI-GaInP:Fe is an appropriate material to be used for thispurpose and the suitability of our cleaning and regrowth methodfor the fabrication of this type of semiconductor lasers.Device characterisation indicates negligible leakage currentalong the etched mesa sidewalls confirming a smooth regrowthinterface. Nevertheless, experimental and simulation resultsreveal that a significant part of the injected current is lostas leakage through the burying material. This is attributed todouble carrier injection into the SI-GaInP:Fe layer.Simulations also predict that the function of GaInP:Fe ascurrent blocking layer should be markedly improved in the caseof GaAs-based longer wavelength lasers.
Keywords:semiconductor lasers, in-plane lasers, VCSELs,GaAs, GaInP, semi-insulating materials, hydride vapour phaseepitaxy, regrowth, buried heterostructure, leakage current,simulation.
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LI, Songyu. "A New Hands-free Face to Face Video Communication Method : Profile based frontal face video reconstruction." Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-152457.
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This thesis proposes a method to reconstruct a frontal facial video basedon encoding done with the facial profile of another video sequence.The reconstructed facial video will have the similar facial expressionchanges as the changes in the profile video. First, the profiles for boththe reference video and for the test video are captured by edge detection.Then, asymmetrical principal component analysis is used to model thecorrespondence between the profile and the frontal face. This allows en-coding from a profile and decoding of the frontal face of another video.Another solution is to use dynamic time warping to match the profilesand select the best matching corresponding frontal face frame for re-construction. With this method, we can reconstructed the test frontalvideo to make it have the similar changing in facial expressions as thereference video. To improve the quality of the result video, Local Lin-ear Embedding is used to give the result video a smoother transitionbetween frames.
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Gangam, Srikanth. "Optical Investigations of Cd Free Cu2ZnSnS4 Solar Cells." University of Toledo / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1345088305.
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Vallée, Christophe. "Dynamics of the free surface of stratified two-phase flows in channels with rectangular cross-sections." Forschungszentrum Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-86493.
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Stratified two-phase flows were investigated at different test facilities with horizontal test sections in order to provide an experimental database for the development and validation of computational fluid dynamics (CFD) codes. These channels were designed with rectangular cross-sections to enable optimal observation conditions for the application of optical measurement techniques. Consequently, the local flow structure was visualised with a high-speed video camera, delivering data with high-resolution in space and time as needed for CFD code validation.
Generic investigations were performed at atmospheric pressure and room temperature in two air/water channels made of acrylic glass. Divers preliminary experiments were conducted with various measuring systems in a test section mounted between two separators. The second test facility, the Horizontal Air/Water Channel (HAWAC), is dedicated to co-current flow investigations. The hydraulic jump as the quasi-stationary discontinuous transition between super- and subcritical flow was studied in this closed channel. Moreover, the instable wave growth leading to slug flow was investigated from the test section inlet. For quantitative analysis of the optical measurements, an algorithm was developed to recognise the stratified interface in the camera frames, allowing statistical treatments for comparison with CFD calculation results.
The third test apparatus was installed in the pressure chamber of the TOPFLOW test facility in order to be operated at reactor typical conditions under pressure equilibrium with the vessel atmosphere. The test section representing a flat model of the hot leg of the German Konvoi pressurised water reactor (PWR) scaled at 1:3 is equipped with large glass side walls in the region of the elbow and of the steam generator inlet chamber to allow visual observations. The experiments were conducted with air and water at room temperature and maximum pressures of 3 bar as well as with steam and water at boundary conditions of up to 50 bar and 264°C. Four types of experiments were performed, including generic test cases as well as transient validation cases of typical nuclear reactor safety issues. As an example, the co-current flow experiments simulate the two-phase natural circulation in the primary circuit of a PWR. The probability distribution of the water level measured in the reactor pressure vessel simulator was used to characterise the flow in the hot leg. Moreover, the flooding behaviour in this conduit was investigated with dedicated counter-current flow limitation experiments. A comparison of the flooding characteristics with similar experimental data and correlations available in the literature shows that the channel height is the characteristic length to be used in the Wallis parameter for channels with rectangular cross-sections. Furthermore, for the analysis of steam/water experiments, condensation effects had to be taken into account. Finally, the experimental results confirm that the Wallis similarity is appropriate to scale flooding in the hot leg of a PWR over a large range of pressure and temperature conditions.
Not least, different examples of comparison between experiment and simulation demonstrate the possibilities offered by the data to support the development and validation of CFD codes. Besides the comparison of qualitative aspects, it is shown exemplarily how to treat the CFD results in order to enable quantitative comparisons with the experiments.