Dissertations / Theses on the topic 'Gas filters'
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Natvig, Ingunn Roald. "Gas cleaning with Granular Filters." Thesis, Norwegian University of Science and Technology, Department of Energy and Process Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-8822.
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The panel bed filter (PBF) is a granular filter patented by A. M. Squires in the late sixties. PBFs consist of louvers with stationary, granular beds. Dust is deposited in the top layers and on the bed surface when gas flows through. PBFs are resistant to high temperatures, variations in the gas flow and hot particles. The filter is cleaned by releasing a pressure pulse in the opposite direction of the bulk flow (a puff back pulse). A new louver geometry patented by A. M. Squires is the filter tray louvers. The new design is believed to reduce the pressure drop and the number of louvers, and to make the filter more compact. We have designed and built a laboratory scale PBF with filter tray louvers based on the patent. Experiments with the prototype show that the new louver can be cleaned with a puff back pulse. A PBF system for a hypothetical biomass combustion plant has been designed. The heat from the flue gas will be used for district heating. The proposed PBF system design consists of double-sided modules with 46 filter tray louvers on top of each other. Five modules are mounted together in module columns, sharing the same clean gas duct and puff back pipe. The granular medium chosen is Sintered Bauxite 20/40 (SB). The module columns are placed in an enveloping house. SB and dust fall into bins in the bottom of the enveloping house during puff back cleaning. A vacuum pneumatic conveying system brings the dust and SB to the top of the filter. Dust and SB are separated in a sieve. Dust is deposited, and SB is transported back to the modules. NTNU is currently involved in the BioSOFC project. The objective of this project is to increase efficiency in energy production from biomass by using producer gas from a biomass gasification plant in a Solid Oxide Fuel Cell. Field tests will be performed at a plant in Güssing, Austria. A PBF will be used for gas filtration. The operating temperature will be 500 °C to avoid tar condensation. We have performed heating experiments on the BioSOFC filter system. The results were not satisfactory, as the temperature in the filter ranged from 384 to 625 °C. The filter system was due to be shipped, and new tests could not be performed. This work proposes that modifications to the heating cable circuits are made, and new heating tests are performed before the field testing.
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Cheung, Chiu Kee. "Dry scrubbing of hydrogen chloride gas using ceramic filters." Thesis, University of Surrey, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362594.
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Alarfaj, Ayman Mohammed Abdullah. "Validation of low resistance filters for gas/vapour sampling." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/4257.
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Traditional occupational hygiene assessment of occupational exposures to organic gases and vapours rely on low flow (<200 ml/min) NIOSH sorbent tubes. This work investigates 3M charcoal filter media (JK50 and JK40, 3M, Inc.) for collection and analysis of organic vapours across 0.1-5 l/min. To enable this work, a custom exposure facility was constructed and validated within which organic analyte gas/vapour concentrations could be introduced at known concentrations while controlling environmental variables such as temperature and humidity and other variables. This facility enabled experiments designed to investigate collection and desorption efficiencies across a range of sample flow rates, temperature and humidity conditions for both NIOSH sorbent tubes (e.g. SKC tube) and 3M charcoal filter media. As a result of the investigations described in this thesis, the following conclusions are drawn. Performance of the 3M charcoal filter media for collection and desorption efficiencies for loading, storage time, humidity and breakthrough at low flow rates (<0.5 l/min) were found comparable to the SKC sorbent tube. It is concluded that 3M charcoal media (JK50 and JK40) are suitable for sampling and analyses of hydrocarbons at flow rates <0.5 l/min. The collection efficiencies of the 3M charcoal filter media were investigated at high flow rates (>0.5l/min) for the same parameters, i.e., loading, temperature and humidity. It is concluded that 3M charcoal filter media can be used with confidence in sampling and analysis of airborne hydrocarbons up to 5 l/min. The Wheeler-Jonas model was found to satisfactorily predict the adsorption kinetics of the 3M charcoal filter media at different loading values of hydrocarbons. It was therefore concluded that the model can be applied to determine the suitable amount of 3M charcoal filter media prior to sampling for a given loading.
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Alarfaj, Ayman M. A. "Validation of Low Resistance Filters for Gas/Vapour Sampling." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/4257.
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Traditional occupational hygiene assessment of occupational exposures to organic gases and vapours rely on low flow (<200 ml/min) NIOSH sorbent tubes. This work investigates 3M charcoal filter media (JK50 and JK40, 3M, Inc.) for collection and analysis of organic vapours across 0.1 ¿ 5 l/min. To enable this work, a custom exposure facility was constructed and validated within which organic analyte gas/vapour concentrations could be introduced at known concentrations while controlling environmental variables such as temperature and humidity and other variables. This facility enabled experiments designed to investigate collection and desorption efficiencies across a range of sample flow rates, temperature and humidity conditions for both NIOSH sorbent tubes (e.g. SKC tube) and 3M charcoal filter media. As a result of the investigations described in this thesis, the following conclusions are drawn.
Performance of the 3M charcoal filter media for collection and desorption efficiencies for loading, storage time, humidity and breakthrough at low flow rates (<0.5 l/min) were found comparable to the SKC sorbent tube. It is concluded that 3M charcoal media (JK50 and JK40) are suitable for sampling and analyses of hydrocarbons at flow rates <0.5 l/min.
The collection efficiencies of the 3M charcoal filter media were investigated at high flow rates (>0.5l/min) for the same parameters, i.e., loading, temperature and humidity. It is concluded that 3M charcoal filter media can be used with confidence in sampling and analysis of airborne hydrocarbons up to 5 l/min.
The Wheeler-Jonas model was found to satisfactorily predict the adsorption kinetics of the 3M charcoal filter media at different loading values of hydrocarbons. It was therefore concluded that the model can be applied to determine the suitable amount of 3M charcoal filter media prior to sampling for a given loading.
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Kornelius, Gerrit. "The design of electrostatically augmented moving bed granular gas filters." Pretoria : [s.n.], 2003. http://upetd.up.ac.za/thesis/available/etd-05052005-095030/.
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Cheung, Kerry. "Chip-scale quadrupole mass filters for a Micro-Gas Analyzer." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/52777.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 181-188).
Mass spectrometers are powerful analytical instruments that serve as the gold standard for chemical analysis. This tool has numerous applications ranging from national security, industrial processing, environmental monitoring, space exploration, and healthcare to name a few. These systems are typically large, heavy, power-hungry, and expensive, constraining its usage to a laboratory setting. In recent years, there has been a growing interest in utilizing mass spectrometers outside the lab. Microelectromechanical systems (MEMS) technology holds the promise of making devices smaller, faster, better, and cheaper. The Micro-Gas Analyzer (MGA) project attempts to leverage MEMS capabilities to create a low-cost, high-performance, portable mass spectrometer. Batch-fabrication of various components for the MGA has been demonstrated to date, but the mass filter component still has room for exploration. Chip-scale quadrupole mass filters achieved entirely through wafer-scale processing have been designed, fabricated, and characterized. The device integrates the quadrupole electrodes, ion optics, and housing into a single monolithic block, eliminating the electrode-to-housing misalignments inherent in other quadrupoles. To achieve this integration, unconventional square electrode geometry was utilized. This concept formed the basis of the micro-square electrode quadrupole mass filter (MuSE-QMF). The MuSE-QMF demonstrated mass filtering with a maximum mass range of 650 amu and a minimum peak-width of 0.5 amu at mass 40, corresponding to a resolution of 80.
(cont.) More importantly, the design concept can be extended to complex architectures that were previously unachievable. Batch-fabricated quadrupoles in arrays, in tandem, or with integrated pre-filters can have significant impact on the future of portable mass spectrometry. Additionally, the MuSE-QMF makes a case for operation in the second stability region, and motivates new studies on quadrupole ion dynamics.
by Kerry Cheung.
Ph.D.
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Lin, Ye Hone. "Evaluation of vibration responses of ceramic candle filters using an accelerometer and a laser vibrometer." Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1369.
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Cardador, Maza David. "Infrared optical filters based in macroporous silicon for espectroscopic gas detection." Doctoral thesis, Universitat Politècnica de Catalunya, 2019. http://hdl.handle.net/10803/673046.
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Gas detection is of great importance in areas as diverse as industry, health or safety in domestic environments or public spaces, among others, and it is highly specific to each application. The detection method depends on factors such as the species of gas to be detected, concentration range, required resolution, sensitivity, specificity, response time, operating environment (temperature, humidity, interfering species, etc.), size and cost, among other considerations.
Optical gas sensors are an attractive solution for gas detection. Most of them rely on molecular absorption and offer fast responses, minimal drift and are intrinsically reliable thanks to perform self-referenced measurements. Sensitivity and selectivity depend on the characteristics of the device. For example, laser-based gas sensors are highly selective with zero cross response to other gases and also with first-in-class sensitivity. The downside is that they are expensive. Non-dispersive infra-red (NDIR) sensors are a widespread alternative for cost-effective optical detection. They have inferior performances in terms of sensitivity and selectivity than laser-based sensors, but are two or three orders of magnitude less expensive.
This thesis is dedicated to improving the selectivity and sensitivity of NDIR devices through the use of macroporous silicon technology. More specifically, it studies how photonic crystals manufactured by electrochemical etching can be used as narrow mid-infrared filters for gas detection purposes. That is, the photonic crystals are designed in such a way that only a small range of frequencies from an external source are transmitted while the surroundings are blocked. These filters are narrower than those available on the market and can be used to improve the selectivity and the sensitivity of NDIR devices as well as to reduce cross detection with other gases. In addition, the study shows how macroporous silicon photonic crystals can be heated to work as selective emitters. This can be used to reduce the complexity of the NDIR device while maintaining similar optical characteristics. Furthermore, it is proven that photonic molecules can be employed to perform dual detection in both transmission and emission, giving a new approach to self-referenced measurements.
Conclusions of the work show that macroporous silicon technology is a versatile platform to provide solutions in the mid-infrared range for developing compact, sensitive and selective optical gas sensing.La detecció de gasos és de gran importància en àrees tan diverses com la indústria, la salut o la seguretat en entorns domèstics o espais públics, entre d'altres, i és altament específica per a cada aplicació. El mètode de detecció a utilitzar depèn de factors com ara el gas a detectar, el rang de concentració, la resolució requerida, la sensibilitat, l'especificitat, el temps de resposta, l'entorn operatiu (temperatura, humitat, espècies interferents, etc. .), la mida i el cost, entre altres consideracions. Els sensors òptics de gas són una solució atractiva per a la detecció de gas. La majoria d'ells es basen en l'absorció molecular i ofereixen respostes ràpides, deriva mínima i són intrínsecament fiables gràcies a la realització de mesures auto-referenciades. La sensibilitat i la selectivitat depenen de les característiques del dispositiu. Per exemple, els sensors de gas basats en tecnologia làser són altament selectius, no presenten resposta creuada a altres gasos i són altament sensibles. El desavantatge és que són cars. Els sensors d'infrarojos no dispersius (NDIR) són una alternativa molt estesa per a la detecció òptica de baix cost. Tenen un rendiment inferior en termes de sensibilitat i selectivitat que els sensors basats en làser, però són dos o tres ordres de magnitud més barats. Aquesta tesi està dedicada a millorar la selectivitat i la sensibilitat dels dispositius NDIR mitjançant la tecnologia de silici macroporós. Més específicament, estudia com els cristalls fotònics fabricats mitjançant el gravat electroquímic poden ser usats com a filtres estrets d'infraroig mitjà per a la detecció de gasos. És a dir, els cristalls fotònics estan dissenyats de tal manera que només un petit rang de freqüències d'una font externa es transmet mentre que els voltants estan bloquejats. Aquests filtres són més estrets que els disponibles en el mercat i poden utilitzar-se per millorar la selectivitat i la sensibilitat dels dispositius NDIR, així com per reduir la detecció creuada amb altres gasos. A més, l'estudi mostra com els cristalls fotònics de silici macroporós poden funcionar com a emissors selectius si són escalfats. Això pot ser usat per reduir la complexitat dels dispositius NDIR alhora que es mantenen característiques òptiques similars. A més, s'ha demostrat que les molècules fotòniques poden emprar-se per realitzar una detecció dual tant en la transmissió com en l'emissió, donant un nou enfocament a les mesures auto-referenciades. Les conclusions del treball mostren que la tecnologia de silici macroporós és una plataforma versàtil que proporciona solucions en el rang d'infraroig mitjà per al desenvolupament de sensors de gas òptics compactes, sensibles i selectius.
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Kiriakidis, Alejandro C. "Implementation and application of NDE on ceramic candle filters." Morgantown, W. Va. : [West Virginia University Libraries], 2003. http://etd.wvu.edu/templates/showETD.cfm?recnum=2831.
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Thesis (Ph. D.)--West Virginia University, 2003.Title from document title page. Document formatted into pages; contains xiv, 185 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 170-176).
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Al-Hajeri, Mohammad Hamad. "Characterization of the fluid flow associated with ceramic candle filters." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323258.
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Rosepiler, Stephen G. "Performance evaluation of diesel particulate filters on heavy duty vehicles." Morgantown, W. Va. : [West Virginia University Libraries], 2003. http://etd.wvu.edu/templates/showETD.cfm?recnum=2867.
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Thesis (M.S.)--West Virginia University, 2003.Title from document title page. Document formatted into pages; contains xii, 114 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 101-103).
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Adigio, Emmanuel M. "Modelling gas flow pressure gradients in Gelcast ceramic foam diesel particulate filters." Thesis, Loughborough University, 2005. https://dspace.lboro.ac.uk/2134/33933.
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Internal combustion engines are significant contributors to air pollution. To meet the future legislative particu1ate matter (PM) emissions targets for diesel engines there is a need for aftertreatment of the exhaust gases. Previous investigations have shown that diesel particulate filters (DPFs) are a potential exhaust aftertreatment technology for the reduction of PM emissions. DPF systems generally contain two elements; one or more filters (i.e. porous media) and a means of regenerating (i.e. cleaning) the filter(s). The filter must be regenerated intermittently or continuously to prevent imposing high exhaust back pressures on the engine. This thesis presents the study of fluid flow through Gelcast ceramic foams that are a potential candidate filter material for use in DPF systems.
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Gonzalez, Sandra C. "Preparation and characterization of new porous ceramic filters for hot gas clean-up." Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-12052009-020046/.
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Peng, Wu Tseng. "Evaluation of ceramic candle filters degradation and damage location using four-point bending tests." Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=1105.
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Thesis (M.S.)--West Virginia University, 1999.Title from document title page. Document formatted into pages; contains x, 85 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 81-82).
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Simmons, Kathy. "An investigation into the deposition of particulate material on ceramic particle filters." Thesis, University of Nottingham, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243347.
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Cheung, W. F. "Filtration and cleaning characteristics of ceramic media." Thesis, University of Surrey, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234580.
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Swan, Dominic. "Stochastic load modelling in gas network analysis and design." Thesis, University of Exeter, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303776.
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Abbassian, F. "Long-running ductile fracture of high pressure gas pipelines." Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372872.
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Palmer, Simon J. "Stabilisation of medium density polyethylene gas pipe in service applications." Thesis, Manchester Metropolitan University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329807.
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Wilt, Glen A. "A parametric study of in-line filter holders." Morgantown, W. Va. : [West Virginia University Libraries], 2004. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=3710.
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Thesis (M.S.)--West Virginia University, 2004.Title from document title page. Document formatted into pages; contains vii, 90 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 67).
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Moles, Nathaniel. "Investigation of techniques and effects of diesel particulate filter cleaning." Morgantown, W. Va. : [West Virginia University Libraries], 2006. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4709.
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Thesis (M.S.)--West Virginia University, 2006.Title from document title page. Document formatted into pages; contains xi, 110 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 87-92).
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Payne, Simon Daniel. "Experimental studies of diesel particulate filtration." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610170.
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Mathur, Pulkit V. D. "Fine-scale modeling of failure in an adhesive layer." Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1454.
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Thesis (M.S.)--West Virginia University, 2000.Title from document title page. Document formatted into pages; contains xviii, 70 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 68-69).
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Leung, Susanna. "Biological Aerated Filters: Oxygen Transfer and Possible Biological Enhancement." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/76962.
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A submerged-media biological aerated filter (BAF) has been studied to 1) evaluate oxygen transfer kinetics under conditions without biological growth and 2) determine the influence of biological growth on the rate of oxygen transfer. Collectively, the study evaluates the rates of supply and consumption of oxygen in BAFs. The mass-transfer characteristics of a submerged-media BAF were initially determined over a wide range of gas and liquid flow rates without the presence of bacteria. The mass-transfer coefficients (KLa(T)) were measured using a nitrogen gas stripping method and were found to increase as both gas and liquid superficial velocities increase, with values ranging from approximately 40 to 380 h??. The effect of parameters including the gas and liquid velocities, dirty water to clean water ratio, and temperature dependence was successfully correlated within +/- 20% of the experimental KLa value. The effects of the media size and gas holdup fractions were also investigated. Stagnant gas holdup did not significantly influence the rate of oxygen transfer. Dynamic gas holdup and the difference between total and stagnant gas holdup were found to increase with an increase in gas velocity. Neither liquid velocity nor liquid temperature was determined to have a significant impact on gas holdup.
A tertiary nitrification BAF pilot unit was then operated for 5 months downstream of a secondary treatment unit at a domestic wastewater treatment facility. The study investigated the oxygen transfer capabilities of the nitrifying unit with high oxygen demand requirements through a series of aeration process tests and explored the presence of oxygen transfer enhancements by further analyzing the actual transfer mechanism limitations. It was determined that (assuming OTE equals 20 percent) aerating the BAF pilot unit based on the stoichiometric aeration demand resulted in overaeration of the unit, especially at lower pollutant loading rates. Endogenous respiration contributed to only 2 to 7 percent of the total oxygen demand with regions of biomass activity changing with varying loading conditions. An enhanced oxygen transfer factor was determined in the biologically active pilot. Although it cannot be definitively concluded that the observed oxygen transfer factor is either due to biological activity or not simply an artifact of measurement/analysis techniques, the enhancement factor can be mathematically accounted for by either an increase in the KLa factor or the associated driving force using a proposed enhanced bubble theory.Master of Science
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Kamoun, Leila. "Etude de filtres MMIC hyperfréquences en technologies GaN et AsGa." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0265/document.
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Ces travaux de thèse portent sur l‟étude de filtres « multi-fonctions » dont l‟objectif serait de réduire les dimensions des circuits réalisant les fonctions de filtrage dans les systèmes aéroportés. Ces travaux ont donc conduit à la réalisation de filtres large bande (2 – 18 GHz) réjecteurs développés en technologie MMIC utilisant la filière GaN, ainsi que des filtres large bande développés suivant la filière AsGa en technologie MMIC. Les différents filtres réjecteurs ont été conçus suivant deux principes :- Le premier basé sur une structure à résonateurs à lignes couplées. Les différents prototypes réalisés ont permis de montrer l‟accordabilité en fréquence grâce à une charge variable placée à l‟extrémité non court-circuité de la ligne couplée. Celle-ci peut être réalisée par une diode varactor ou par un transistor froid. Ces prototypes ont également permis de montrer la possibilité de fonctionner suivant un mode passe-tout ou un mode réjecteur par simple polarisation de transistors chargés à l‟extrémité de la ligne couplée.- Le second est basé sur l‟accordabilité de filtres actifs par commutation entre plusieurs canaux à l‟aide d‟une structure distribuée. Un prototype a été développé et réalisé en technologie AsGa. Cette structure permet à la fois une accordabilité en fréquences, ainsi qu‟en largeur de bande passante (par activation de plusieurs canaux de bandes passantes adjacentes), et une adaptation large bande. Cette structure réunit à la fois des fonctions d‟accordabilité en fréquences (entre 8,7 et 15,6 GHz) par polarisation d‟éléments actifs, ceux-ci permettant même d‟obtenir du gain (de l‟ordre de 10 dB)The aim of this work is to study “multi-functions” filters with an objective to reduce the dimensions of the circuits used for filtering functions in airborne systems. This work allows to obtain wide band notch filters (from 2 to 18 GHz) developed in MMIC technology using theEtude de Filtres MMIC Hyperfréquences en Technologies GaN et AsGa. 152GaN process and wide band filters developed in GaAs technology. The notch filters have been realized with two principles:- The first one based on coupled lines resonators structure. The prototype manufactured allow to validate the frequency tunability thanks to a variable load placed at the end of the coupled line. This can be realized with a varactor diode or with a cold transistor. These prototypes allow also validating the possibility for the circuit to work as an “allpass” filter or as a notch filter by applying a bias voltage on the transistors placed at the end of the coupled line.- The second one is based on the tenability of active filters by commuting between several channels thanks to a distributed structure. A prototype has been developed and manufactured in GaAs technology. This structure allow a frequency tunability with also the possibility to tune the bandwidth (by activating seeral channels with edge bandwidth), and a wide band matching. This structure allows to obtain frequency tunability (between 8.7 and 15.6 GHz) by applying a bias voltage on the active elements which brin gain (around 10 dB)
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Ndinisa, Nkosinathi Vincent Chemical Sciences & Engineering Faculty of Engineering UNSW. "Experimental and CFD simulation investigations into fouling reduction by gas-liquid two-phase flow for submerged flat sheet membranes." Awarded by:University of New South Wales. School of Chemical Sciences and Engineering, 2006. http://handle.unsw.edu.au/1959.4/32872.
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Submerged flat sheet membranes are mostly used in membrane bioreactors for wastewater treatment. The major problems for these modules are concentration polarization and subsequent fouling. By using gas-liquid two-phase flow, these problems can be ameliorated. This thesis aimed to optimize the use of gas-liquid two-phase flow as a cleaning mechanism for submerged flat sheet membrane. The effect of various hydrodynamic factors such as airflow rate, nozzle size, nozzle geometry, intermittent bubbling, intermittent filtration, channel gap width, feed concentration and membrane baffles were investigated for model feed materials (yeast suspensions and mixed liquor from activated sludge plants). Insights into mechanisms by which two-phase flow reduces fouling for submerged flat sheet membranes were obtained by using Computational Fluid Dynamics. Experiments conducted showed that an optimal airflow rate exists beyond which no further flux enhancement was achieved. Fouling reduction increased with nozzle size at constant airflow. Nozzles of equal surface area but different geometries performed differently in terms of fouling reduction. Bubble size distribution analyses revealed that the percentage of larger bubbles and bubble rise velocities increased with the airflow rate and nozzle size. Thus the results of this study suggest that the effectiveness of two-phase flow depends on the bubble size. CFD simulations revealed that average shear stress on the membrane increased with airflow rate and bubble size and further indicated that an optimal bubble size possible exists. Using intermittent filtration as an operating strategy was found to be more beneficial than continuous filtration. This study also showed the importance of the size of the gap between the submerged flat sheet membranes. Increasing the gap from 7 mm to 14 mm resulted in an increase in fouling by about 40% based on the rate of increase in suction pressure (dTMP/dt). Finally, this is the first study which investigated the effect of baffles in improving air distribution across a submerged flat sheet membrane. It was found that baffles decreased the rate of fouling at least by a factor of 3.0 based on the dTMP/dt data.
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Ames, Robin W. "Analysis of a 2007 EPA compliant diesel particulate matter sampling system." Morgantown, W. Va. : [West Virginia University Libraries], 2007. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5245.
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Thesis (M.S.)--West Virginia University, 2007.Title from document title page. Document formatted into pages; contains xv, 133 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 91-95).
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Rincón, Juan Pablo. "Development of a test facility to evaluate hot gas filtration characteristics of a candle filter." Morgantown, W. Va. : [West Virginia University Libraries], 2003. http://etd.wvu.edu/templates/showETD.cfm?recnum=2912.
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Thesis (M.S.)--West Virginia University, 2003.Title from document title page. Document formatted into pages; contains xii, 121 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 117-119).
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Karra, Jagadeswarareddy. "Development of porous metal-organic frameworks for gas adsorption applications." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/45751.
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Metal-organic frameworks are a new class of porous materials that have potential applications in gas storage, separations, catalysis, sensors, non-linear optics, displays and electroluminescent devices. They are synthesized in a "building-block" approach by self-assembly of metal or metal-oxide vertices interconnected by rigid linker molecules. The highly ordered nature of MOF materials and the ability to tailor the framework's chemical functionality by modifying the organic ligands give the materials great potential for high efficiency adsorbents. In particular, MOFs that selectively adsorb CO₂ over N₂, and CH₄ are very important because they have the potential to reduce carbon emissions from coal-fired power plants and substantially diminish the cost of natural gas production. Despite their importance, MOFs that show high selective gas adsorption behavior are not so common.
Development of MOFs for gas adsorption applications has been hindered by the lack of fundamental understanding of the interactions between the host-guest systems. Knowledge of how adsorbates bind to the material, and if so where and through which interaction, as well as how different species in adsorbed mixture compete and interact with the adsorption sites is a prerequisite for considering MOFs for adsorptive gas separation applications. In this work, we seek to understand the role of structural features (such as pore sizes, open metal site, functionalized ligands, pore volume, electrostatics) on the adsorptive separation of CO₂, CO and N₂ in prototype MOFs with the help of molecular modeling studies (GCMC simulations). Our simulation results suggest that the suitable MOFs for CO₂ adsorption and separation should have small size, open metal site, or large pore volume with functionalized groups.
Some of the experimental challenges in the MOF based adsorbents for CO₂ capture include designing MOFs with smaller pores with/without open metal sites. Constructing such type of porous MOFs can lead to greater CO₂ capacities and adsorption selectivities over mixtures of CH₄ or N₂. Therefore, in the second project, we focused on design and development of small pore MOFs with/without open metal sites for adsorptive separation of carbon dioxide from binary mixtures of methane and nitrogen. We have synthesized and characterized several new MOFs (single ligand and mixed ligand MOFs) using different characterization techniques like single-crystal X-ray diffraction, powder X-ray diffraction, TGA, BET, gravimetric adsorption and examined their applicability in CO₂/N₂ and CO₂/CH₄ mixture separations. Our findings from this study suggest that further, rational development of new MOF compounds for CO₂ capture applications should focus on enriching open metal sites, increasing the pore volume, and minimizing the size of large pores.
Flue gas streams and natural gas streams containing CO₂ are often saturated by water and its presence greatly reduces the CO₂ adsorption capacities and selectivities. So, in the third project, we investigated the structural stability of the developed MOFs by measuring water vapor adsorption isotherms on them at different humid conditions to understand which type of coordination environment in MOFs can resist humid environments. The results of this study suggest that MOFs connected through nitrogen-bearing ligands show greater water stability than materials constructed solely through carboxylic acid groups.
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MANSERVIGI, LUCREZIA. "Detection and classification of fults and anomalies in gas turbine sensors by means of statistical filters and machine learning models." Doctoral thesis, Università degli studi di Ferrara, 2021. http://hdl.handle.net/11392/2478821.
Full textAbstract:
Il monitoraggio e la diagnosi delle turbine a gas sono essenziali e possono essere efficacemente effettuati solo se i sensori installati forniscono una misura attendibile del funzionamento della macchina.
Perciò, l’affidabilità dei sensori è un prerequisito indispensabile ai fini di valutare l’effettivo stato di salute della macchina. Infatti, un sensore guasto potrebbe fornire informazioni inesatte, causando perciò l’interruzione della produzione e un incremento dei costi di manutenzione.
Per questo motivo, questa tesi sviluppa, calibra e valida metodologie finalizzate ad individuare e classificare i guasti e le anomalie dei sensori installati nelle turbine a gas.
La tesi documenta due attività di ricerca con cui è stato raggiunto l’obiettivo prefissato.
In primo luogo, è stato sviluppato lo strumento diagnostico denominato “Improved Detection, Classification and Integrated Diagnostics of Gas Turbine Sensors” (I-DCIDS). Tale strumento è costituito dal Fault Detection Tool e Sensor Overall Health State Analysis (SOHSA). Il Fault Detection Tool individua e classifica le categorie di guasto più frequenti. Invece, SOHSA valuta lo stato di salute complessivo del sensore.
I-DCIDS può essere utilizzato per valutare lo stato di salute sia di sensori singoli sia di sensori ridondanti/correlati, utilizzando equazioni matematiche che richiedono il settaggio di alcuni parametri di configurazione. A tal fine, viene effettuata un’analisi di sensibilità mediante quattro set di dati eterogenei per definire il valore ottimale di tali parametri. Successivamente, I-DCIDS viene validato su un ulteriore set di dati.
Inoltre, I-DCIDS viene anche utilizzato per valutare lo stato di salute di numerosi sensori, analizzando un elevato numero di dati, rappresentativi di sei grandezze fisiche. Queste analisi sono volte ad individuare regole generali con l’obiettivo di determinare la magnitudo del guasto del sensore e l’istante di tempo in cui si verifica.
I risultati ottenuti testimoniano la capacità diagnostica di I-DCIDS sul campo sperimentale. Inoltre, si dimostra che la nuova metodologia può analizzare qualsiasi tipo di dataset e grandezza fisica; infatti, grazie al suo settaggio ottimale, I-DCIDS può anche individuare l’esatto istante di tempo in cui il guasto si è verificato.
Un altro studio condotto in questa tesi riguarda la valutazione dell’affidabilità dei dati acquisiti, che può essere compromessa a causa di anomalie di processo. Questa tipologia di anomalie, raramente investigata in letteratura, può causare errori tali per cui l’unità di misura di un sensore viene erroneamente assegnata. In questa tesi, tale situazione è denominata “Unit Of Measure Inconsistency” (UMI).
Quindi, il secondo obiettivo di questa tesi è quello di individuare lo strumento migliore per diagnosticare con successo l’UMI e per assegnare la corretta unità di misura ai dati privi di tale informazione. A tal fine, vengono esaminati tre classificatori di Machine Learning supervisionato, cioè Support Vector Machine, Naive Bayes e K-Nearest Neighbor. Inoltre, viene proposta ed analizzata una nuova metodologia, chiamata Improved Nearest Neighbor.
Le potenzialità di ogni classificatore sono valutate mediante numerose analisi, per verificare come l’affidabilità dei dati utilizzati in fase di addestramento e il numero di classi influenzino le prestazioni delle varie metodologie.
Si dimostra che il classificatore Naive Bayes e l’Improved Nearest Neighbor sono i più promettenti in termini di efficacia, robustezza e generalità nel maggior numero di casi considerati. In questo modo, si può assegnare la corretta unità di misura e la diagnosi del sensore potrà quindi essere effettuata efficacemente.
Si segnala infine che tutte le analisi riportate in questa tesi utilizzano dati sperimentali acquisiti da sensori installati su turbine a gas di Siemens.Monitoring and diagnostics of gas turbines is a key challenge that can be performed only if the unit is equipped with reliable sensors, thus providing the actual operating condition of the energy system under investigation. Thus, the evaluation of sensor reliability is fundamental since only a reliable measurement can lead to proper decisions about system operation and health state. In fact, a faulty sensor may provide misleading information for decision making, at the expense of business interruption and maintenance-related costs. For this reason, this thesis develops, tunes and validates comprehensive methodologies for the detection and classification of both faults and anomalies affecting gas turbine sensors. This purpose is achieved by means of two different analyses and related tools. First, the Improved Detection, Classification and Integrated Diagnostics of Gas Turbine Sensors (I-DCIDS) tool is developed. The I-DCIDS tool comprises two kernels, namely Fault Detection Tool and Sensor Overall Health State Analysis (SOHSA). The former detects and classifies the most frequent fault classes. The latter evaluates the sensor overall health state. The novel diagnostic tool is suitable for assessing the health state of both single sensors and redundant/correlated sensors. The methodology uses basic mathematical laws that require some user-defined configuration parameters. Thus, a sensitivity analysis is carried out on I-DCIDS parameters to derive their optimal setting. The sensitivity analysis is performed on four heterogeneous and challenging field datasets referring to correlated sensors. Then, the I-DCIDS tool is validated by means of an additional field dataset, by proving its detection capability. Furthermore, the I-DCIDS tool is also exploited to evaluate the health state of several single sensors, by analyzing a huge amount of field data that refer to six different physical quantities. These analyses provide some rules of thumb for field operation, with the final aim of identifying time occurrence and magnitude of faulty sensors. The results demonstrate the diagnostic capability of the I-DCIDS approach in a real-world scenario. Moreover, the methodology proves to be suitable for all types of datasets and physical quantities and, thanks to its optimal tuning, also capable of identifying the actual time point of fault onset. A further challenge addressed in this thesis relies on the evaluation of raw data reliability, which may be compromised because of process anomalies. Such anomalies, which have been rarely investigated in the literature, may introduce errors whereby the unit of measure of a sensor is wrongly assumed. In this thesis such a situation is named Unit of Measure Inconsistency (UMI). Thus, this thesis is also aimed at identifying the approach that is mostly able to successfully detect UMI occurrence and classify unlabeled data. Among several alternatives, the capability of three supervised Machine Learning classifiers, i.e., Support Vector Machine, Naïve Bayes and K-Nearest Neighbors is investigated. In addition, a novel methodology, namely Improved Nearest Neighbor is proposed and investigated. The capability of each classifier is assessed by means of several analyses, so that the influence of the reliability of the data used for training the classifier and the number of classes is investigated. Among all tested approaches, the Naïve Bayes classifier and the novel Improved Nearest Neighbor prove to be the most effective, since they demonstrate their effectiveness, robustness and general validity in the majority of the cases. Thanks to the selected classifiers, the actual unit of measure of raw data can be provided and further sensor diagnoses can be safely performed. Finally, it has to be highlighted that all analyses reported in this thesis make use of field data acquired from sensors installed on Siemens gas turbines.
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Thompson, Michael Thomas. "Fast amplitude and delay measurement for characterization of optical devices." Texas A&M University, 2006. http://hdl.handle.net/1969.1/4440.
Full textAbstract:
A fast measurement technique based on the modulation phase-shift technique is
developed to measure the wavelength-dependent magnitude and phase responses of
optical devices. The measured phase response is in the form of group delay, which is
used to determine the chromatic dispersion in the device under test by taking the
derivative of the group delay with respect to optical wavelength. The measurement
setup allows both step-tunable and sweeping laser sources. A modulation frequency of
up to 2.7 GHz is accommodated. An alternate method for the phase measurement that
overcomes non-linearities in the measurement setup is also presented. The speed of the
measurement setup is limited by the sweeping speed of the laser source, which for the
Agilent 81682A is 40 nm/sec. The magnitude accuracy is determined by taking a
comparison to the commercially available Micron Finisar measurement system, where
an error of 0.125 dB is noted. The phase accuracy of the measurement setup is tested
by taking the Hilbert transform of the measured magnitude response of an Acetylene
gas cell and comparing it to the integral of the measured group delay. The average
deviation between the two methods is 0.1 radians. An Acetylene gas cell, fiber Bragg
grating, and chirped Bragg grating are tested with the measurement setup and the
Agilent 8168The characterization of the setup leads to the conclusion that the measurement setup
developed in this paper is fast and accurate. The speed of the technique is on the order
of microseconds for a single measurement and excels beyond the speed of the standard
modulation phase-shift technique, which includes measurement times on the order of
minutes. The accuracy of the technique is within 0.125 dB for magnitude
measurements and 0.1 radians for phase measurements when compared to
commercially available measurement systems.2A laser source at 40 nm/sec and the measurement plots are presented.
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Huang, Xinyu. "Mechanics and Durability of Fiber Reinforced Porous Ceramic Composites." Diss., Virginia Tech, 2001. http://hdl.handle.net/10919/26063.
Full textAbstract:
Porous ceramics and porous ceramic composites are emerging functional materials
that have found numerous industrial applications, especially in energy conversion
processes. They are characterized by random microstructure and high porosity.
Examples are ceramic candle filters used in coal-fired power plants, gas-fired
infrared burners, anode and cathode materials of solid oxide fuel cells, etc.
In this research, both experimental and theoretical work have been conducted to
characterize and to model the mechanical behavior and durability of this novel
class of functional material. Extensive experiments were performed on a hot gas
candle filter material provided by the McDermott Technologies Inc (MTI). Models at
micro-/meso-/macro- geometric scales were established to model the porous ceramic
material and fiber reinforced porous ceramic material. The effective mechanical
properties are of great technical interest in many applications. Based on the
average field formalism, a computational micromechanics approach was developed to estimate
the effective elastic properties of a highly porous material with random microstructure.
A meso-level analytical model based on the energy principles was developed to estimate
the global elastic properties of the MTI filament-wound ceramic composite tube.
To deal with complex geometry, a finite element scheme was developed for
porous material with strong fiber reinforcements. Some of the model-predicted elastic
properties were compared with experimental values. The long-term performance of ceramic
composite hot gas candle filter materials was discussed. Built upon the stress analysis
models, a coupled damage mechanics and finite element approach was presented to assess
the durability and to predict the service life of the porous ceramic composite
candle filter material.Ph. D.
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Fargnoli, Amélia Giovana. "Estudo da compressibilidade de tortas de filtração de gases em filtros de tecido." Universidade Federal de São Carlos, 2010. https://repositorio.ufscar.br/handle/ufscar/4072.
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Previous issue date: 2010-03-31Universidade Federal de Sao Carlos
A study on the compressibility of gas filtration cakes through their porosity investigation is presented in this work. The experimental unit consisted of a circular filter with a filtration area of 249 cm2 and a data acquisition system; mass flow rate and relative air humidity were controlled. The filter media used were a polyester felt (weighing 600 g/cm2) and an acrylic felt (weighing 550 g/cm2). A phosphate concentrate phosphate (ρp = 3.20 g/cm3 and dSt = 5.6 μm) and a magnesium silicate (talc) (ρp = 3.09 g/cm3 and dSt = 2.5 μm) were used as powder materials. Superficial filtration velocity was kept constant at 10 cm/s during phosphate concentrate filtration trials and five maximum pressure drops were set (100, 300, 600, 900 and 1200 mmH2O) at constant mass flow rate. Superficial filtration velocity was kept constant at 10 cm/s during talc filtration trials and four maximum pressure drops were set (300, 600, 900 and 1200 mmH2O) at constant mass flow rate. Trials at different filtration velocities (7.5 cm/s, 10 cm/s, 12.5 cm/s and 15.0 cm/s) were also performed. Initially, porosity data as a function of pressure drop per time were obtained. Each cake underwent a process to acquire the necessary resistance to be cut and embedded and then analyzed by a Scanning Electron Microscope. The obtained images were treated and analyzed in an image analyzing software which provided cakes porosity values. Afterwards, the influence of gas superficial velocity on average porosity was evaluated for cakes formed by talc powder. The porosity values obtained with the SEM images were compared to those obtained with equations found in the literature. A difference of 20 to 48% between experimental average porosity and estimated porosity was found for the phosphate concentrate cakes and of less than 13% for the talc cakes obtained at constant velocity. The average porosity values found for talc cakes were higher than those found for phosphate concentrate cakes, which was probably due to the fact that talc particles shape is extremely different from the spherical shape. A compressibility behavior for cakes of the two materials was possible to be observed. Talc cake porosity decreased with the increase of superficial filtration velocity.
Nesse trabalho apresenta-se um estudo da compressibilidade de tortas de filtração de gases através da investigação de sua porosidade. A unidade experimental consistiu de um filtro circular com área livre de filtração de 249 cm2, com vazão mássica e umidade relativa do ar controladas e um sistema de aquisição de dados. Os meios filtrantes utilizados foram um feltro de poliéster (gramatura 600 g/cm2) e um de acrílico (gramatura 550 g/cm2). Os materiais pulverulentos usados foram um concentrado fosfático (ρp = 3.20 g/cm3 e dSt = 5,6 μm) e um silicato de magnésio (talco) (ρp = 3,09 g/cm3 e dSt = 2,5 μm). Para os ensaios de filtração com a rocha fosfática foi fixada a velocidade superficial de filtração em 10 cm/s e cinco quedas de pressão máximas (100, 300, 600, 900 e 1200 mmH2O) à vazão mássica constante. Para os ensaios de filtração com o talco foi fixada a velocidade em 10 cm/s e quatro quedas de pressão máximas (300, 600, 900 e 1200 mmH2O) à vazão mássica constante. Também foram realizados ensaios para o talco a diferentes velocidades (7,5 cm/s, 10 cm/s, 12,5 cm/s e 15,0 cm/s). Inicialmente, obtiveram-se dados experimentais de porosidade em função da queda de pressão por tempo de filtração. Cada torta obtida passou por um tratamento para adquirir resistência necessária e ser analisada em um Microscópio Eletrônico de Varredura. As imagens obtidas foram tratadas e analisadas em um programa de análise de imagem fornecendo o valor da porosidade da torta. Posteriormente, analisou-se a influência da velocidade superficial de filtração na porosidade média de tortas de filtração formadas pelo talco. Compararam-se os valores de porosidade obtidos pelas imagens geradas no MEV com os obtidos por equações da literatura. Encontrou-se uma diferença de 20 a 48% entre os valores de porosidade média experimental e estimada para as tortas de rocha fosfática e de menos de 13% para o talco a velocidade constante. Os valores de porosidade média encontrados para o talco foram maiores que os encontrados para a rocha, provavelmente devido ao fato de que o formato das partículas de talco se distancia muito do formato esférico. Foi possível detectar um comportamento de compressibilidade para as tortas dos dois materiais. A porosidade das tortas de talco tendeu a diminuir com o aumento da velocidade superficial de filtração.
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Nakamura, Masamichi, and Kazuhiro Yamamoto. "Simulation of heat conduction and soot combustion in diesel particulate filter." Inderscience publishers, 2012. http://hdl.handle.net/2237/20055.
Full text
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Bohuš, Michal. "Návrh systému pro hlášení úniku plynu pomocí ultrazvukového mikrofonu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-316449.
Full textAbstract:
The aim of this project is detection of gass leak based on the ultrasound sensing. Work introduces ultrasound, mechanism of its propagation and attenuation. From all of the available microphones, the piezoelectric microphone was chosen. Project continues with description of the device, which can be capable of detection of the ultrasound leakage in dangerous, explosive environment. This type of device must meet requirements of SIL 2 standard and ATEX directive for zone 2. Project discusses LNA (Low Noise Amplifier), filters and detection circuits design. The device is modular what means that each module can be freely replaced. The role of these modules is to convert analog signal to digital form suitable for microcontroller HERCULES TSM57012.
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Spinelle, Laurent. "Microsystèmes capteurs de gaz sélectifs au dioxyde d'azote associant structures semi-conducteurs et filtres chimiques (indigo ou/et nanomatériaux carbonés) destinés au contrôle de la qualité de l'air." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2012. http://tel.archives-ouvertes.fr/tel-00741969.
Full textAbstract:
Ce manuscrit est consacré à l'étude et au développement de microsystèmes capteurs de gaz sélectifs au dioxyde d'azote, destinés au contrôle de la qualité de l'air atmosphérique. La stratégie que nous avons développée consiste à associer une structure sensible à base de matériaux semi-conducteurs partiellement sélectifs aux gaz oxydants et des filtres sélectifs à l'ozone. L'objectif premier est la mise en oeuvre et la caractérisation de matériaux chimiques strictement imperméables à l'ozone (O3) et non-réactifs vis-à-vis du dioxyde d'azote (NO2). Notre choix s'est focalisé sur un matériau moléculaire, l'indigo, connu pour sa réactivité vis-à-vis de O3, et plusieurs nanomatériaux carbonés. Pour ces derniers, la possibilité de conformer leurs textures, leurs morphologies et leurs chimies de surface par traitements thermiques, chimiques et mécaniques, permet d'étendre le panel de matériaux potentiels et d'identifier les facteurs d'influence de leur réactivité avec les espèces gazeuses. La caractérisation de l'ensemble de ces matériaux a nécessité l'utilisation de techniques adaptées et complémentaires (adsorption de N2 à 77 K, spectroscopies Raman, XPS, IR en mode ATR, RPE et NEXAFS). Les filtres chimiques les plus efficaces (hauts rendements de filtration et grande durabilité) ont été sélectionnés d'après des tests de soumission aux gaz selon une méthodologie adaptée. Enfin, l'association de ces meilleurs filtres et de la structure capteur a conduit à l'élaboration de prototypes microsystèmes capteurs de gaz optimisés. De plus, une contribution à la compréhension des mécanismes d'interaction de l'indigo et de certains nanocarbones avec O3 et NO2 a aussi permis d'améliorer le microsystème en développant des méthodologies pertinentes et innovantes mais également en réalisant la synthèse de nouveaux filtres indigo / nanocarbone.
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Peterson, Emily Cassidy. "Shear-induced microstructure in hollow fiber membrane dopes." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50245.
Full textAbstract:
Hollow fiber membranes offer the opportunity to dramatically reduce the energy required to perform gas separations in the chemical industry. The membranes are fabricated from highly non-Newtonian precursor materials, including concentrated polymer solutions that sometimes also contain dispersed particles. These materials are susceptible to shear-induced microstructural changes during processing, which can affect the characteristics of the resulting membrane. This thesis explores several shear-related effects using materials and flow conditions that are relevant for fiber spinning. The findings are discussed as they relate to membrane processing, and also from the standpoint of enhancing our fundamental understanding of the underlying phenomena.
First, the effect of shear on polymeric dope solutions was investigated. Shear-induced demixing—a phenomenon not previously studied in membrane materials—was found to occur in membrane dopes. Phase separation experiments also showed that shear-induced demixing promotes macrovoid formation. The demixing process was found to depend not only on the instantaneous shear conditions, but also on the shear history of the solution. This suggests that low-shear flow processes that occur in the upstream tubing and channels used for fiber spinning can affect macrovoid formation.
The effect of viscoelastic media on dispersed particles was also explored. Shear-small-angle light scattering results showed that particles suspended in membrane dope solutions formed aggregated, vorticity-oriented structures when shear rates in the shear-thinning regime of the polymer solution were applied. Shear rates well below the shear-thinning regime did not produce any structure. In fact, the application of a Newtonian shear rate to a sample already containing the vorticity structure caused the sample to return to isotropy. Measurements using a highly elastic, constant-viscosity Boger fluid showed that strong normal forces alone are not sufficient to form the vorticity structures, but that shear thinning is also required.
Lastly, a study was conducted examining cross-stream migration of particles dispersed in viscoelastic media. Fluids exhibiting varying degrees of shear thinning and normal forces were found to have different effects on the particle distribution along the shear gradient axis in Poiseuille flow. Shear thinning was found to promote migration toward the channel center, while normal stresses tended to cause migration toward the channel walls.
In addition to hollow fiber spinning, many other industrially relevant applications involve polymer solutions and suspensions of particles in viscoelastic media. Often, the properties and performance of the material depend strongly on the internal microstructure. The results from the research described in this thesis can be used to guide the design of materials and processing conditions, so that the desired microstructural characteristics can be achieved.
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Ødegård, Johnny. "Gas Cleaning with Granular Bed Filter." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-12892.
Full textAbstract:
A literature study is first presented then the practical experiments are described. The theoretical chapter provides an overview of filtration mechanisms and available gas cleaning technologies, with an emphasis on hot gas and cake filtration. The experimental chapters describe the setup and testing of the filter tray test rig and the L10-56 test rig.The filter tray test rig was built, instrumentation was installed and programming performed. Puff-back calibration and heating tests were performed. The puff-back calibration showed that a significantly lower delta p minimum was obtained with this design compared to previous designs. Filtration tests were conducted at an elevated temperature (120 C) with different dust concentrations (1 and 3 g/m3) and filtration velocities (10 - 20 cm/s). The results showed that the rig was working in accordance with the design criteria, with a filtration efficiency above 99,5%.A previously used filter test rig, the L10-56 test rig, was installed at the slipstream of the exhaust of a oil sand extraction pilot plant at 350⁰C. A horizontal bed unit (HBU) was also developed to investigate the impacts of the exhaust gas on the granular filter media. Once completed, the rig was re-tested and the puff-back calibration and heating tests that were performed achieved results corresponding with the previous testis performed on this test rig. The test rig was ready to start filtration tests but they were not initiated due to time limitations and unpredicted halt of the oil sand extraction pilot plant.
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Sullivan, Michael R. "Leak detection in gas transmission pipelines." Thesis, Curtin University, 2003. http://hdl.handle.net/20.500.11937/881.
Full textAbstract:
This dissertation applies a commercial flow simulation software package together with common signal processing techniques to the task of accurately detecting leakage in a large commercial gas pipeline. The techniques developed significantly improved the ability to produce accurate, reliable and stable leak detection predictions for the gas transmission pipeline studied and can be applied generally to other pipelines as well. Recommendations for minimum pipeline requirements to implement successful leak detection are also detailed. There are several commercial software packages available that perform some form of leak detection via system modelling. However, due to the commercial aspects of these products, vendors do not publish the detailed methods of leak detection. This thesis identifies the fundamental techniques required to have accurate and reliable leak detection on a gas transmission pipeline, whilst taking into account the lack of measurement data typically encountered on most gas pipelines. The investigation confirmed that a mass balance technique could be successfully used to produce stable leak detection results for compressible flow in gas transmission pipelines. This leak detection [using mass balance] can be achieved without flow measurement along the pipeline, instead, using only pressure and temperature measurements. Although it is recognized that flow measurement data will greatly improve the ability to detect leaks, the focus of this work is on pipelines where this flow measurement data at intermediate points along the pipeline is not available. It was also demonstrated the reliability of the leak detection was improved by the application of on-line signal processing techniques at various stages of the data processing.It was clear early into the investigation that the majority of the errors within the leak detection model were created by random errors from the input field data. These non-systematic errors from the measurement data that included pressure and temperature, produced interference with model output. This interference resembled random “white” noise that was removed by a combination of well established data filtering techniques. The most appropriate process of calculating leak detection flow was determined after analysing the results of different techniques applied to large quantities of actual pipeline operating data. The validation of the on-line techniques developed provides a valuable resource for those wishing to implement similar leak detection schemes elsewhere. Furthermore a software environment was chosen which incorporated an open input and output platform for data that could be interfaced with any operating system. Therefore these techniques can be applied to the numerous Supervisory Control and Data Acquisition (SCADA) systems in operation throughout the gas transmission industry, to provide a low cost solution to leak monitoring.
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Sullivan, Michael R. "Leak detection in gas transmission pipelines." Curtin University of Technology, School of Engineering, 2003. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=15189.
Full textAbstract:
This dissertation applies a commercial flow simulation software package together with common signal processing techniques to the task of accurately detecting leakage in a large commercial gas pipeline. The techniques developed significantly improved the ability to produce accurate, reliable and stable leak detection predictions for the gas transmission pipeline studied and can be applied generally to other pipelines as well. Recommendations for minimum pipeline requirements to implement successful leak detection are also detailed. There are several commercial software packages available that perform some form of leak detection via system modelling. However, due to the commercial aspects of these products, vendors do not publish the detailed methods of leak detection. This thesis identifies the fundamental techniques required to have accurate and reliable leak detection on a gas transmission pipeline, whilst taking into account the lack of measurement data typically encountered on most gas pipelines. The investigation confirmed that a mass balance technique could be successfully used to produce stable leak detection results for compressible flow in gas transmission pipelines. This leak detection [using mass balance] can be achieved without flow measurement along the pipeline, instead, using only pressure and temperature measurements. Although it is recognized that flow measurement data will greatly improve the ability to detect leaks, the focus of this work is on pipelines where this flow measurement data at intermediate points along the pipeline is not available. It was also demonstrated the reliability of the leak detection was improved by the application of on-line signal processing techniques at various stages of the data processing.It was clear early into the investigation that the majority of the errors within the leak detection model were created by random errors from the input field data. These non-systematic errors from the measurement data that included pressure and temperature, produced interference with model output. This interference resembled random “white” noise that was removed by a combination of well established data filtering techniques. The most appropriate process of calculating leak detection flow was determined after analysing the results of different techniques applied to large quantities of actual pipeline operating data. The validation of the on-line techniques developed provides a valuable resource for those wishing to implement similar leak detection schemes elsewhere. Furthermore a software environment was chosen which incorporated an open input and output platform for data that could be interfaced with any operating system. Therefore these techniques can be applied to the numerous Supervisory Control and Data Acquisition (SCADA) systems in operation throughout the gas transmission industry, to provide a low cost solution to leak monitoring.
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Käll, Viktor, and Erik Piscator. "Particle Filter Bridge Interpolation in GANs." Thesis, KTH, Matematisk statistik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-301733.
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Generative adversarial networks (GANs), a type of generative modeling framework, has received much attention in the past few years since they were discovered for their capacity to recover complex high-dimensional data distributions. These provide a compressed representation of the data where all but the essential features of a sample is extracted, subsequently inducing a similarity measure on the space of data. This similarity measure gives rise to the possibility of interpolating in the data which has been done successfully in the past. Herein we propose a new stochastic interpolation method for GANs where the interpolation is forced to adhere to the data distribution by implementing a sequential Monte Carlo algorithm for data sampling. The results show that the new method outperforms previously known interpolation methods for the data set LINES; compared to the results of other interpolation methods there was a significant improvement measured through quantitative and qualitative evaluations. The developed interpolation method has met its expectations and shown promise, however it needs to be tested on a more complex data set in order to verify that it also scales well.Generative adversarial networks (GANs) är ett slags generativ modell som har fått mycket uppmärksamhet de senaste åren sedan de upptäcktes för sin potential att återskapa komplexa högdimensionella datafördelningar. Dessa förser en komprimerad representation av datan där enbart de karaktäriserande egenskaperna är bevarade, vilket följdaktligen inducerar ett avståndsmått på datarummet. Detta avståndsmått möjliggör interpolering inom datan vilket har åstadkommits med framgång tidigare. Häri föreslår vi en ny stokastisk interpoleringsmetod för GANs där interpolationen tvingas följa datafördelningen genom att implementera en sekventiell Monte Carlo algoritm för dragning av datapunkter. Resultaten för studien visar att metoden ger bättre interpolationer för datamängden LINES som användes; jämfört med resultaten av tidigare kända interpolationsmetoder syntes en märkbar förbättring genom kvalitativa och kvantitativa utvärderingar. Den framtagna interpolationsmetoden har alltså mött förväntningarna och är lovande, emellertid fordras att den testas på en mer komplex datamängd för att bekräfta att den fungerar väl även under mer generella förhållanden.
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Martin, Graham S. "Theoretical and experimental studies of an aerosol coalescing fibrous filter." Thesis, University of Newcastle Upon Tyne, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265545.
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Kuhl, David Derieg. "Assimilation of trace gas retrievals with the Local Ensemble Transform Kalman Filter." College Park, Md. : University of Maryland, 2009. http://hdl.handle.net/1903/9984.
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Thesis (Ph.D.) -- University of Maryland, College Park, 2009.Thesis research directed by: Dept of Atmospheric and Oceanic Sciences. 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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Lancaster, Greg A. "A Tunable Electromagnetic Band-gap Microstrip Filter." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/952.
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In high frequency design, harmonic suppression is a persistent struggle. Non-linear devices such as switches and amplifiers produce unwanted harmonics which may interfere with other frequency bands. Filtering is a widely accepted solution, however there are various shortcomings involved. Suppressing multiple harmonics, if desired, with traditional lumped element and distributed component band-stop filters requires using multiple filters. These topologies are not easily made tunable either. A new filter topology is investigated called Electromagnetic Band-Gap (EBG) structures.
EBG structures have recently gained the interest of microwave designers due to their periodic nature which prohibits the propagation of certain frequency bands. EBG structures exhibit characteristics similar to that of a band-stop filter, but in periodically repeating intervals making it ideal for harmonic suppression. The band-gap frequency of an EBG structure may be varied by altering the periodicity of the structure. However, EBG materials are generally static in structure making tuning a challenge.
In this thesis, a novel solution for tuning the band-gap properties of an EBG structure is investigated. Designs aimed to improve upon existing solutions are reached. These designs involve acoustic and mechanical tuning methods. Performance is simulated using Agilent’s Advanced Design System (ADS) and a device is constructed and evaluated. Comparing all measured test cases to simulation, band-gap center frequency error is on average 4.44% and absolute band-gap rejection error is 1.358 dB.
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Shinozaki, Osamu, Hirohide Furutani, Masaki Misawa, Naoki Takada, Kazuki Yamauchi, and Kazuhiro Yamamoto. "Lattice Boltzmann simulation on continuously regenerating diesel filter." The Royal Society, 2011. http://hdl.handle.net/2237/20056.
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Taylor, Eric. "Filter weighing procedure for 2007 and newer heavy duty diesel engines." Morgantown, W. Va. : [West Virginia University Libraries], 2006. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4788.
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Thesis (M.S.)--West Virginia University, 2006.Title from document title page. Document formatted into pages; contains xii, 100 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 87-91).
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Hanaki, Yasunari, and Kazuhiro Yamamoto. "Microfluidic Simulation of Diesel Exhaust Gas and Soot Oxidation in Diesel Particulate Filter." SAE International, 2013. http://hdl.handle.net/2237/20341.
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Franco, Kleber Serrão. "Filtração de gases a altas pressões." Universidade Federal de São Carlos, 2012. https://repositorio.ufscar.br/handle/ufscar/4106.
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Previous issue date: 2012-10-31The filtration of gases is an important industrial operation with the primary aim of removing unwanted solid particles contained in a gas. The filtration of gases at high pressures is an operation widely used in natural gas industry with the aim of separating impurities called black powder, from rust inside pipelines along the transportation. These residues can cause wear on equipment such as, for example, rotor pump, obstruction of gauges and pressure decrease in product quality. Despite being an operation widely used, few studies exist in the area to study what the best type of filter. Therefore this study is very useful to improve the steps of transportation, measurement and purity of the final product. To simulate this process, we used the dry compressed air, injecting a phosphate rock as particulate matter. The filters were tested RAD cellulose and acrylic. The surface speed of filtration was kept constant at 0.05 m / s, throughout the filtering operation. The flow of compressed air used were 14 l / min to the total pressure 1 bar, 42 l / min at a total pressure of 3 bar and 86 l / min at a total pressure of 6 bar. Total load losses were 5, 10, 20 and 30 mbar. The results showed that, initially, the curves of head loss versus deposited mass showed the same growth trend. However, when forming a layer of cake from about 0.03 kg/m2, the filtrations higher pressures had lower pressure loss. This is because the larger pressure forming pies more porous and less resistant to air flow. At the end of the study it was also observed that the acrylic filter performed better compared to the cellulose RAD, due to its greater mass of accumulated dust and low pressure drop.
A filtração de gases é uma importante operação industrial com o principal intuito de remover as partículas sólidas indesejadas contidas em um determinado gás. A filtração de gases a altas pressões é uma operação muito utilizada na indústria de gás natural com o objetivo de separar as impurezas denominadas pó preto, provenientes da oxidação no interior de gasodutos ao longo do seu transporte. Estes resíduos podem causar desgaste de equipamentos como, por exemplo, rotor de bombas, obstrução de aparelhos de medição de pressão e diminuição da qualidade do produto. Apesar de ser uma operação muito utilizada, poucas pesquisas existem na área a fim de estudar qual o melhor tipo de filtro. Por isso este estudo é muito útil no sentido de melhorar as etapas de transporte, medição e pureza do produto final. Para simular este processo, foi utilizado o ar comprimido seco, injetando-se a rocha fosfática como material particulado. Os filtros testados foram de celulose RAD+ e acrílico. A velocidade superficial de filtração foi mantida constante em 0,05 m/s, durante toda a operação de filtração. As vazões do ar comprimido utilizadas foram de 14 l/min para a pressão total de 1 bar, 42 l/min para a pressão total de 3 bar e 86 l/min para a pressão total de 6 bar. As perdas de carga totais foram de 5, 10, 20 e 30 mbar. Os principais resultados mostraram que, inicialmente, as curvas de perda de carga versus massa depositada apresentaram igual tendência de crescimento. Porém, no momento que forma uma camada de torta a partir de aproximadamente 0,03 kg/m2, as filtrações de maiores pressões apresentaram menor perda de carga. Isso porque as maiores pressões formam tortas mais porosas e menos resistentes ao escoamento de ar. Ao final do estudo observou-se também que o filtro de acrílico obteve melhor desempenho comparado com o de celulose RAD+, por apresentar maior massa de pó acumulada e menor perda de carga.
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Votava, Jakub. "Jednotka pro energetické využití kontaminováné biomasy." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-228990.
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The purpose of the thesis is to create preliminary design calculations to determine dimensions, weights and pressure losses of individual contaminated biomass combustion gas treatment nodes. The first part of the thesis deals with the definition of biomass as a fuel, legislative determination of allowed emissions and their description. Then the systems for combustion gas treatments are discussed given their brief description. The practical part focuses on shape designs, determining base dimensions of each type. Weights and pressure losses of individual versions are computed too. In the last part the individual versions are solved with real values and compared to each other.
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Mader, Brian T. "Gas/solid and gas/particle partitioning of polychlorinated dibenzodioxins, polychlorinated dibenzofurans and polycyclic aromatic hydrocarbons to filter surfaces and ambient atmospheric particulate material /." Full text open access at:, 2000. http://content.ohsu.edu/u?/etd,193.
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