Щоб переглянути інші типи публікацій з цієї теми, перейдіть за посиланням: EMISSION ANALYSIS.
Дисертації з теми "EMISSION ANALYSIS"
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-50 дисертацій для дослідження на тему "EMISSION ANALYSIS".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте дисертації для різних дисциплін та оформлюйте правильно вашу бібліографію.
1
Kim, Tae-Kyung. "Dynamic analysis of sulfur dioxide monthly emissions in U.S. power plants." Columbus, Ohio : Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1086195964.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--Ohio State University, 2004.Title from first page of PDF file. Document formatted into pages; contains xviii, 218 p.; also includes graphics. Includes abstract and vita. Advisor: Jean Michael Guldmann, City and Regional Planning Graduate Program. Includes bibliographical references (p. 130-133).
2
Reniers, Jorn. "Analysis of a real-time signal for greenhouse gas emissions of district heating consumption." Thesis, KTH, Industriell ekologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-169508.
Повний текст джерелаАнотація:
The district heating system (DHS) of Stockholm is one of the largest systems in the world with a total yearly production of 10TWh of heat and 2TWh of electricity (through combined heat and power plants). Large amounts of greenhouse gasses (GHG) are emitted to produce this heat and electricity. Given the goal of the City of Stockholm to reduce the amount of GHG emissions to 3 ton per capita in 2015 and to keep reducing emissions at a similar rate after 2015, it is important to identify the potentials for further reductions. Numerous studies have been done on how the DHS can become more sustainable by installing new generation units. However, also the consumers have an influence on the DHS. After all, it are the consumers who decide when and how much heat or electricity they use. Most former studies and environmental guidelines for the DHS in Stockholm focussed on the producer side. This thesis looks at the consumer perspective of the (heat of the) district heating system. A real-time signal giving the greenhouse gas emissions of individual households is developed and its potential and challenges are discussed. With this signal, households that want to minimise their environmental impact have a tool to decrease their environmental impact by changing their consumption. This can be a first step to transform the DHS to a smart district heating system. First, generic models to calculate the dynamic greenhouse gas intensity of the heat production of district heating and to calculate the greenhouse gas emissions related to the heat consumption of households are suggested. Then the feedback signal with those real-time household emissions is calculated for representative households in Stockholm based on data of Stockholm’s DHS and data about hot tap water consumption in Sweden. Results indicate that variations in household level greenhouse gas emissions mostly reflect changes in consumption but can also result from changes by the producer. Intraday variations are mostly caused by changes in hot tap water consumption, while variations on a timescale of a few days are caused by changes in heating consumption (changing weather) and changes made by the producer (to use different fuels). Then several scenarios are calculated, each scenario looking at the actions a consumer can take to shift or reduce his/her consumption (decrease hot tap water usage, lower indoor temperature etc.). The real-time household emissions are calculated again to see if the signal gives the needed incentives (is the household rewarded for its effort? Does it get further incentives?). It was found that a strong time-incentive (to decrease consumption when it saves most emissions) is missing if the average perspective is used to calculate the emission intensity of the heat production. Also, the results confirmed the finding that the feedback signal might not reflect changes in consumption. Finally, challenges for the signal are discussed. One of the major hurdles is the fact that household consumption of heat (heating and hot tap water) can often not be measured on a household level. Thus, it has to be estimated but it seems very difficult to get this estimation accurate enough to give correct feedback to households, especially about the emissions saved by their efforts to reduce/shift their consumption. Secondly, the time resolution should be chosen well to still get accurate results but not make the signal to data-intensive. Finally, the result is heavily dependent on the chosen methodology (average or marginal perspective? Do you account for the electrical side of the DHS? How about the distribution losses? Etc.).
3
Sayeed, Abdul. "Positron emission tomography analysis of Alzheimer's disease." Thesis, University of Surrey, 2001. http://epubs.surrey.ac.uk/842834/.
Повний текст джерелаАнотація:
Alzheimer's Disease (AD) is a major concern for the elderly population, currently affecting over 670,000 people in the UK. With the continual increase in the age of the population the problem is expected to rise. There is no known cure to the condition and a definite diagnosis cannot be made in life. Clinical diagnosis is considered to be approximately 80% - 90% accurate, sometimes taking up to a year to assess. Early detection could aid in the care and possible development of better treatments or even a cure. AD has been shown to alter the structure and global texture of the brain. Studies using Magnetic Resonance imaging (MRI) and Computerised Tomography (CT) have been used to detect these changes with some success by some researchers. Positron Emission Tomography (PET) imaging is a functional imaging modality and in theory before structural changes are evident functional changes should be apparent. Therefore we utilise PET images for this study. This thesis will exploit the fact that AD alters the global texture of the brain. Texture features extracted from fluoro-deoxy-glucose (FDG) PET images and sinograms of the brain will be used. Most texture feature extraction methods fail, due to poor signal to noise ratio so we will use a novel texture feature extraction method known as the Trace transform - triple features, which can extract features directly from raw data acquired by PET scanners. Classifiers will be used to aid in the separation of the two groups, namely AD patients and normal controls. The Trace transform - triple feature method has proven its potential as a good feature extraction technique. It enabled us to achieve classification accuracy of up to 93% on raw sinogram data using a combination of five features. This result is very good compared with the clinical accuracy of 80% reported by most researcher. It is comparable to results obtained by Kippenhan et al [52, 53, 51, 50], who used regional metabolic activity using PET and a neural network classifier. Monomial features extracted from images achieved accuracies as high as 87%. These features are good discriminators, however, they suffer from lack of scaling invariance. This is problematic as brain sizes do vary considerably. The use of registration and extraction of regional information failed to produce fruitful results. This is principally due to poor registration. The registration failed primarily because a very small cross section of the brain was available. Also the effect of AD alters the structure of the brain. Since the registration relies on matching structure, it becomes questionable whether one can actually register automatically a very degraded AD brain. Gender and age are crucial to the progress of Alzheimer's disease. Age and gender matching is not sufficient to get the best results. This thesis has shown that performance gains of up to 11% can be attained by simply incorporating age and/or gender into the classification model. However, the maximum classification accuracy was not improved any further.
4
Mathiyaparanam, Jeyisanker. "Analysis of acoustic emission in cohesionless soil." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001715.
Повний текст джерела
5
Elfergani, Hisham. "Acoustic emission analysis of prestressed concrete structures." Thesis, Cardiff University, 2013. http://orca.cf.ac.uk/49383/.
Повний текст джерелаАнотація:
This thesis examines the role of Acoustic Emission (AE) as a non-destructive testing (NDT) technique for prestressed and reinforced concrete structures. The work focuses on the development of experimental techniques and data analysis methods for the detection, location and assessment of AE from prestressed and reinforced concrete specimens. This thesis reveals that AE can be used to detect the onset of corrosion activity in wire in the interface between prestressed concrete and mortar as found in prestressed concrete pipes. Furthermore, this technique can be used to locate the corrosion activity on different size prestressed concrete samples. By correlation between three parameters of classical AE analysis techniques (traditional parameters), damage can be detected and located whilst the corrosion area, macro crack and crack propagation can be identified. However, it cannot classify the crack type. Different damage modes, including corrosion activity, micro/macro cracking formation, crack propagation and wire failure generate different types of AE signals with varying amplitudes and absolute energy emitted. A novel analysis approach has been used on composite materials (concrete, mortar and steel) to evaluate differing crack types by a combination of the classical acoustic emission analysis technique and advanced analysis Rise time / Amplitude (RA) and Average Frequency (AF), results proved the effectiveness of the developed techniques for damage detection and classification crack types. The relationship between RA value and AF value can be used to determine the crack area and classify it as either tensile crack type, other type (shear movement) or no crack. The results of the research have demonstrated that the AE technique is valid in larger scale monitoring and hence the potential for monitoring real structures such as prestressed concrete pipes. Use of Kernel Density Estimation Function (KDEF) provides improved visualisation of the data to represent clearly the RA/AF values. Key Words: Acoustic Emission, Corrosion, Reinforced Concrete, Prestressed Concrete, Micro and Macro Concrete Cracks, Crack classification, Source Location, Damage Assessment, Monitoring.
6
Erickson, Brice Carl. "Multicomponent flow injection analysis and quantitative infrared emission spectroscopy : chemometric applications /." Thesis, Connect to this title online; UW restricted, 1988. http://hdl.handle.net/1773/8633.
Повний текст джерела
7
Nemalapuri, Vijay Krishna. "Impact of Traffic Operations on Carbon Monoxide Emissions Analysis." University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1282322424.
Повний текст джерела
8
Pell, Randall James. "Chemometrics and infrared emission spectroscopy for remote analysis /." Thesis, Connect to this title online; UW restricted, 1990. http://hdl.handle.net/1773/11545.
Повний текст джерела
9
Link, Christoph, Juliane Stark, Axel Sonntag, and Reinhard Hössinger. "Contribution of an emission trading scheme to reduce road traffic induced CO2 emissions in Austria." Elsevier, 2012. http://dx.doi.org/10.1016/j.sbspro.2012.06.1170.
Повний текст джерелаАнотація:
The Emission Trading Scheme for green house gases is a key tool of European climate protection. Including the road transport sector might be a promising strategy to limit its CO2 emissions. This could be realized within a common market (trans-sectoral trading permitted) or separated markets (trans-sectoral trading not permitted). Starting from different assumptions on emission reduction objectives, the impact of both options is analyzed using a quantitative model. Although an emission trading scheme is ecologically effective regardless of the trading model, it turns out that CO2 emissions and emission allowance prices differ strongly between both design options due to sector specific price elasticities of allowance demand. (authors' abstract)
10
Vidal, Meliá Lidia. "Analysis of environmental policy and emission control instruments." Doctoral thesis, Universitat Jaume I, 2020. http://hdl.handle.net/10803/668542.
Повний текст джерелаАнотація:
The debate on the emissions control instruments for improving environmental policy is the inspiration of the present thesis. In a first attempt, we use a theoretical model to study how international trade affects the governments' decision on their industrial policy. We show that the countries' market size might drive the regulator's decision on the optimal industry policy.
We also use laboratory methods to evaluate the impact of different combinations of instruments, compliances, and timings on firms' investment incentives. The asymmetric model of Requate and Unold, 2001 is the base of our experimental design by allocating different initial technologies to the firms, where firms can adopt an advanced abatement technology, which is the same for all firms. In particular, this thesis attempts to demonstrate whether this procedure induces an optimal allocation of investment decisions.La inspiración de la presente tesis gira entorno al debate sobre los instrumentos de control de emisiones para mejorar la política ambiental. En un primer intento, utilizamos un modelo teórico para estudiar cómo el comercio internacional afecta la decisión de los gobiernos sobre su política industrial. Mostramos que el tamaño del mercado de los países podría impulsar la decisión del regulador sobre la política óptima de la industria. También empleamos métodos de laboratorio para evaluar el impacto de diferentes combinaciones de instrumentos, cumplimientos y tiempos en los incentivos de inversión de las empresas. El diseño experimental se basa en el modelo asimétrico de Requate and Unold, 2001 al asignar diferentes tecnologías iniciales a las empresas, donde las empresas pueden adoptar una tecnología de reducción avanzada, que es la misma para todas las empresas. En particular, esta tesis intenta demostrar si este procedimiento induce una asignación óptima de las decisiones de inversión.
11
Li, Yulin. "Analysis of green-house gas emission in China." Thesis, KTH, Kemiteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-220945.
Повний текст джерелаАнотація:
Today China produces most GHG emissions in the world, which continues increasing the average temperature of the Earth. For the purpose of reducing the emission and reaching the peak of GHG emission before 2030, Chinese government promotes several policies, such as developing renewable energy, importing advanced emission reduction technology and encouraging the production and sales of new energy vehicles. In order to estimate the tendency of Chinese GHG emission, a review has been conducted. This review has considered the current Chinese situation, making necessary assumptions and calculating total emission in several relevant sectors independently. By adjusting several key figures, the end result of peak year may be changed. The review has proved that the peak year for Chinese GHG emissions will be 2035 under normal condition. If other optimized factors are considered, the peak year could be moved up.
12
Reilly, John M., and Sergey Paltsev. "An Analysis of the European Emission Trading Scheme." MIT Joint Program on the Science and Policy of Global Change, 2005. http://hdl.handle.net/1721.1/29792.
Повний текст джерелаАнотація:
An international emissions trading system is a featured instrument in the Kyoto Protocol to the Framework Convention on Climate Change, designed to reduce emissions of greenhouse gases among major industrial countries. The US was the leading proponent of emissions trading in the negotiations leading up to the Protocol, with the European Union initially reluctant to embrace the idea. However the US withdrawal from the Protocol has greatly changed the nature of the agreement. One result is that the EU has moved rapidly ahead, establishing in 2003 the Emission Trading Scheme (ETS) for the period of 2005-2007. This Scheme was intended as a test designed to help its member states transition to a system that would lead to compliance with their Kyoto Protocol commitments, which cover the period 2008-2012. The ETS covers CO2 emissions from big industrial entities in the electricity, heat, and energy-intensive sectors. It is a system that itself is evolving as allocations, rules, and registries were still being finalized in some member states late into 2005, even though the system started in January of that year. We analyze the ETS using the MIT Emissions Prediction and Policy Analysis (EPPA) model. We find that a competitive carbon market clears at a carbon price of about 0.6 to 0.9 €/tCO2 (approximately 2 to 3 €/tC) for the 2005-2007 period in a base run of our model in line with many observers’ expectations who saw the cuts required under the system as very mild, but in sharp contrast to the actual history of trading prices, which have settled in the range of 20 to 25 €/tCO2 (approximately 70 to 90 €/tC) by the middle of 2005. In various comparison exercises the EPPA model’s estimates of carbon prices have been similar to that of other models, and so the contrast between projection and reality in the ETS raises questions regarding the potential real cost of emissions reductions vis-à-vis expectations previously formed based on results from the modeling community. While it is beyond the scope of this paper to reach firm conclusions on reasons for this difference, what happens over the next few years will have important implications for greenhouse gas emissions trading and so further analysis of the emerging European trading system will be crucial.Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).
This research was supported by the U.S Department of Energy, U.S. Environmental Protection Agency, U.S. National Science Foundation, U.S. National Aeronautics and Space Administration, U.S. National Oceanographic and Atmospheric Administration; and the Industry and Foundation Sponsors of the MIT Joint Program on the Science and Policy of Global Change: Alstom Power (France), American Electric Power (USA), Chevron Corporation (USA), CONCAWE (Belgium), DaimlerChrysler AG (Germany), Duke Energy (USA), J-Power (Japan), Electric Power Research Institute (USA), Electricité de France, ExxonMobil Corporation (USA), Ford Motor Company (USA), General Motors (USA), Murphy Oil Corporation (USA), Oglethorpe Power Corporation (USA), RWE Power (Germany), Schlumberger (USA), Shell Petroleum (Netherlands/UK), Southern Company (USA), Statoil ASA (Norway), Tennessee Valley Authority (USA), Tokyo Electric Power Company (Japan), Total (France), G. Unger Vetlesen Foundation (USA).
13
伊藤, 義人, Yoshito Itoh, 徹哉 北川, and Tetsuya Kitagawa. "Using CO2 emission quantities in bridge lifecycle analysis." Elsevier, 2002. http://hdl.handle.net/2237/160.
Повний текст джерела
14
Anderson, David Robert. "Laser-induced emission spectrometry for rapid elemental analysis." Thesis, Sheffield Hallam University, 1994. http://shura.shu.ac.uk/19273/.
Повний текст джерелаАнотація:
This thesis reports investigations into laser-induced emission spectrometry for rapid elemental analysis. An integrated laser and spectrometer system is configured, comprising a Q-switched Nd:YAG laser and an optical multichannel analyser, which enables the discreet monitoring of the laser-induced plasma produced by each laser shot. Novel applications are devised including the survey analysis of polymeric materials and the depth profiling of coated steels. A survey analysis of polymeric materials for twelve elements (Al, Ba, Ca, Cu, Fe, Mg, Pb, P, Sb, Sn, Ti and Zn) is reported. Results showed that element emission responses are dependent upon operating conditions, selective volatilisation of antimony can occur, and ablation characteristics, such as the rate of material removal and plasma lifetime, are very different compared to metals. With optimised operating conditions of low laser energy and sample positioned at the laser focal point, the limit of detection for antimony is 0.09 % mass/mass with precision of 1.8 (% relative standard deviation) using a carbon signal from the polymer as internal standard. Rapid discrimination between samples of poly (vinyl chloride) is demonstrated with a measurement time of 1 s. Data for the depth profiling of a range of coated steels using laser-induced plasma emission spectrometry are reported in detail for the first time. Coatings of zinc/nickel, tin, titanium nitride and chromium are examined. Depth profile signatures and crater shape are greatly influenced by operating conditions. Improved depth resolution and signatures are obtained using high laser energy and defocused laser radiation. Correlations are established between coating thickness and output parameters of the technique. Linear calibrations against coating thickness are achieved with good precision for replicate measurements (4 % relative standard deviation). Results showed that the technique can differentiate between tin coated samples with a difference in coating thickness of 0.02 pm, and can detect an ultra-thin chromium coating of 0.020 pm thickness. This performance and measurement times of 50 s indicate the rapid depth profile capability of the technique. The novel application of an artificial intelligence technique (artificial neural networks) to laser-induced plasma emission spectra is reported for the first time. Studies showed that artificial neural networks can rapidly discriminate between the emission spectra of different materials with a success rate of 100 %, to provide a new means of rapid data processing.
15
Miller, D. G. "Acoustic emission analysis of an automotive paint system." Thesis, Imperial College London, 1987. http://hdl.handle.net/10044/1/47293.
Повний текст джерела
16
Mannarini, Gianandrea. "Speckle Analysis of the Excitonic Emission fromQuantum Wells." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2005. http://dx.doi.org/10.18452/15264.
Повний текст джерелаАнотація:
In der vorliegenden Promotionsarbeit werden optische Eigenschaften von Halbleiterquantengräben untersucht, die mit der Ausbildung von Speckle-Mustern in der exzitonischen Emission zusammenhängen. Die in nichtspekulärer Richtung nach resonanter Anregung von Exzitonen ausgestrahlte Emission enthält Informationen über Unordnung und Streuprozesse in der Probe. Im Kapitel "Spektrale Speckle-Analyse" wird gezeigt, dass Speckles zur Bestimmung des koährenten Anteils verwendet werden können. Außerdem kann die innerhalb des inhomogen verbreiterten Ensembles frequenzaufgelöste Lebensdauer der Exzitonen bestimmt werden. Eine mikroskopische Dichtematrixtheorie wird entwickelt und numerisch gelöst. Es wird eine gute Übereinstimmung mit den gemessenen Daten für unterschiedliche Quantengraben-Dicken und Temperaturen gefunden. Im Kapitel "Schrägliegende Speckles" werden Quantengräben mit mechanischer Verzerrung betrachtet. Die Verzerrung führt zu einer ort-abhängigen Änderung der Emissionsenergie in der Ebene des Quantengrabens und das richtungs- und zeitaufgelöste Specklemuster erfährt eine Drehung. Die theoretische Beschreibung des Rayleigh-Spektrums erlaubt es, diese Drehung mit dem lokalen Wert des Gradienten der Exzitonenergie in Beziehung zu setzen. Numerische Simulationen zeigen allerdings, dass dieser Effekt nicht durch eine Bewegung der Exzitonen entlang des Verzerrungs-Gradienten verursacht wird. Im Kapitel "Nicht-Markovsche Exziton-Phonon Dynamik" die Dichtematrixtheorie, wird jenseits der Markovschen Näherung für die Streuung von Exzitonen an akustischen Phononen numerisch gelöst. Das Absorptionsspektrum besteht aus Lorentz-formige Peaks und breiteren Seitenbändern, die aus der nicht-Markovschen Kopplung stammen. Diese Eigenschaften sind vor allem für die stark lokalisierten Zustände auf der Niederenergie-Seite des Spektrums wichtig, und erlauben eine bessere Deutung von Nahfeld-Experimenten.In this work, optical properties of semiconductor quantum wells (QW) are investigated, which are relevant for the irregular light pattern (speckle pattern) emitted in nonspecular directions by QW after resonant excitation of the exciton states. This emission contains information on disorder and scattering processes in the sample. In Chapter "Spectral Speckle Analysis", it is shown that Speckles can be used for extraction of the coherent part of the emission, the Resonant Rayleigh Scattering. Furthermore, the frequency resolved lifetime of excitons within an inhomogeneously broadened ensemble can be established. A microscopic density matrix theory for excitons interacting with acoustic phonons is developed and numerically solved. Good agreement with the experimental results for different QW sizes and temperatures is found. In Chapter "Sloped Speckles" QW with mechanical strain are considered. The strain leads to a spatially dependent modification of the emission energy and to a tilting of the direction- and time-resolved speckle pattern. The theoretical description of the RRS relates this tilting to the local value of the spatial gradient of the exciton energy. However, numerical simulations make clear that this effect is not due to exciton motion along the strain gradient. In Chapter "Non-Markovian exciton-phonon dynamics" the density matrix theory is numerically solved beyond the Markov approximation for the interaction between excitons and acoustical phonons. The resulting absorption spectrum consists of Lorentzian peaks on top of broader sidebands originating from the non-Markovian coupling. These features are mostly important for the strongly localized states in the low energy side of the spectrum, suggesting a better interpretation of near-field experiments.
17
Gesley, Mark Alan. "Spectral analysis of field emission flicker (1/f) noise." Full text open access at:, 1985. http://content.ohsu.edu/u?/etd,85.
Повний текст джерела
18
Mannarini, Gianandrea. "Speckle analysis of the excitonic emission from quantum wells." [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=975390414.
Повний текст джерела
19
Carpenter, Robert Christopher. "Inductively coupled plasma-optical emission spectrometry for forensic analysis." Thesis, University of Plymouth, 1985. http://hdl.handle.net/10026.1/2680.
Повний текст джерелаАнотація:
The fundamental characteristics and applications of inductively coupled plasma - optical emission spectrometry (ICP-OES) for forensic science purposes have been evaluated. Optimisation of ICP-OES for single elements using simplex techniques identified an ICP torch fitted with a wide bore injector tube as most suitable for multielement analysis because of a compact analytical region in the plasma. A suitable objective function has been proposed for multielement simplex optimisation of ICP-OES and its effectiveness has been demonstrated. The effects of easily ionisable element (EIE) interferences have been studied and an interference minimisation simplex optimisation shown to be appropriate for the location of an interference free zone. Routine, interference free determinations (<2% for 0.5% Na) have been shown to be critically dependant on the stability of the injector gas flowrate and nebuliser derived pressure pulses. Discrete nebulisation has been investigated for the analysis of small fragments of a variety of metal alloys which could be encountered in casework investigations. External contamination together with alloy inhomogeneity have been shown to present some problems in the interpretation of the data. A compact, corrosion resistant recirculating nebuliser has been constructed and evaluated for the analysis of small fragments of shotgun steels. The stable aerosol production from this nebuliser allowed a set of element lines, free from iron interferences, to be monitored with a scanning monochromator. The analysis, classification and discrimination of casework sized fragments of brasses and sheet glasses have been performed and a method has been proposed for the analysis of white household gloss paints. The determination of metal traces on hands following the handling of a variety of metal alloys has been reported. The significance of the results from these evidential materials has been assessed for forensic science purposes.
20
Sparkes, Simon Timothy. "Agricultural analysis by plasma emission spectroscopy with slurry atomisation." Thesis, University of Plymouth, 1986. http://hdl.handle.net/10026.1/2145.
Повний текст джерелаАнотація:
The three electrode direct current plasma (DCP), has been investigated for the analysis of samples introduced using aqueous solution nebulisation, hydride generation and slurry atomisation. For aqueous solutions, simplex optimisation with signal to background ratio as the criterion of merit, vertical viewing position was found to be most critical. A continuous-flow hydride generator was interfaced to the DCP via a modified sample introduction chimney. Optimisation indicated that total sample introduction gas flow rates were essentially similar to those for conventional nebulisation and that vertical viewing position was again critical. Generation conditions for lead hydride were also simplex optimised. Acid, sodium hydroxide, and hydrogen peroxide concentration were all found to be critical. Detection limits for hydride generation were: As 4 ng cmˉ³, Se 4 ng cmˉ³, Pb 10 ng cmˉ³. Arsenic and selenium were accurately determined in various reference materials. The determination of Mg in aqueous slurries of kaolin was optimised using the Mg(II) 279.079 nm line and conventional sample introduction. Vertical viewing position was again critical with the optimum on the boundary of the analytical zone and over the plasma core. A reduction of emission intensity at high slurry concentrations (> 12%), was observed. Particle size was the most important parameter in slurry atomisation, < 5 µm being preferred. Soils, milk, plant materials and sewage sludges were successfully analysed by slurry atomisation. Where necessary, particle size was reduced using simple grinding procedures. For fibrous materials, prior matrix carbonisation was advantageous. Results obtained using these procedures and simple aqueous calibration showed excellent agreement with certified values of reference materials. Electron number density (ne), excitation temperature (Texc) and ionisation temperature (Tion), were measured for two series of kaolin slurries, (1-20% m/V), one containing 5 g 1ˉ¹ lithium as enhancement buffer. For the slurries containing added lithium, Texc and ne were found to be reduced with increasing slurry concentration. Observed decreases in analyte emission with increased sample loadings (> 12%), are considered to be consistent with proposed excitation models.
21
Yang, Yao-Joe. "Numerical analysis and design strategy for field emission devices." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/80591.
Повний текст джерела
22
Mirhadizadeh, S. A. "Monitoring hydrodynamic bearings with acoustic emission and vibration analysis." Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/7888.
Повний текст джерелаАнотація:
Acoustic emission (AE) is one of many available technologies for condition
health monitoring and diagnosis of rotating machines such as bearings. In
recent years there have been many developments in the use of Acoustic
Emission technology (AET) and its analysis for monitoring the condition of
rotating machinery whilst in operation, particularly on high speed machinery.
Unlike conventional technologies such as oil analysis, motor current signature
analysis (MCSA) and vibration analysis, AET has been introduced due to its
increased sensitivity in detecting the earliest stages of loss of mechanical
integrity.
This research presents an experimental investigation that is aimed at
developing a mathematical model and experimentally validating the influence of
operational variables such as film thickness, rotational speed, load, power loss,
and shear stress for variations of load and speed conditions, on generation of
acoustic emission in a hydrodynamic bearing. It is concluded that the power
losses of the bearing are directly correlated with acoustic emission levels. With
exponential law, an equation is proposed to predict power losses with
reasonable accuracy from an AE signal.
This experimental investigation conducted a comparative study between AE
and Vibration to diagnose the rubbing at high rotational speeds in the
hydrodynamic bearing. As it is the first known attempt in rotating machines. It
has been concluded, that AE parameters such as amplitude, can perform as a
reliable and sensitive tool for the early detection of rubbing between surfaces of
a hydrodynamic bearing and high speed shaft.
The application of vibration (PeakVue) analysis was introduced and compared
with demodulation. The results observed from the demodulation and PeakVue
techniques were similar in the rubbing simulation test. In fact, some defects on
hydrodynamic bearings would not have been seen in a timely manner without
the PeakVue analysis.In addition, the application of advanced signal processing and statistical
methods was established to extract useful diagnostic features from the acquired
AE signals in both time and frequency domain. It was also concluded that the
use of different signal processing methods is often necessary to achieve
meaningful diagnostic information from the signals. The outcome would largely
contribute to the development of effective intelligent condition monitoring
systems which can significantly reduce the cost of plant maintenance.
To implement these main objectives, the Sutton test rig was modified to assess
the capability of AET and vibration analysis as an effective tool for the detection
of incipient defects within high speed machine components (e.g. shafts and
hydrodynamic bearings).
The first chapter of this thesis is an introduction to this research and briefly
explains motivation and the theoretical background supporting this research.
The second and third chapters, summarise the relevant literature to establish
the current level of knowledge of hydrodynamic bearings and acoustic emission,
respectively. Chapter 4 describes methodologies and the experimental
arrangements utilized for this investigation. Chapter 5 discusses different NDT
diagnosis. Chapter 6 reports on an experimental investigation applied to
validate the relationship between AET on operational rotating machines, such
as film thickness, speed, load, power loss, and shear stress. Chapter 7 details
an investigation which compares the applicability of AE and vibration
technologies in monitoring a rubbing simulation on a hydrodynamic bearing.
23
Matthews, N. "Models of molecular line emission from star formation regions." Thesis, University of Kent, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381427.
Повний текст джерела
24
Grecchi, Elisabetta. "Multiresolution image analysis : innovative applications for Positron Emission Tomography in clinical practice." Thesis, King's College London (University of London), 2016. https://kclpure.kcl.ac.uk/portal/en/theses/multiresolution-image-analysis(b7d71602-2274-426f-a81d-22327efd3402).html.
Повний текст джерелаАнотація:
Positron Emission Tomography is an excellent tool to image physiological processes in vivo and it is of great potential when it comes to disease staging for targeted therapies. However, the potential of PET imaging is somewhat limited by its low spatial resolution with resulting significant partial volume effect (PVE) that deteriorates the accuracy of the quantification of the physiological process under scrutiny. In this context, the use of multimodality imaging is very convenient to resolve this limitation. Using novel techniques based on a multiresolution approach, it is possible to recover PET resolution by a synergistic coupling of the PET images with the anatomical counterpart, either CT or MRI. The multiresolution analysis is performed through a wavelet decomposition of both functional and anatomical images which has been used already in the past with similar purposes. The aim of this thesis is to present novel multiresolution partial volume correction (PVC) techniques that target two different clinical applications. The first part of the project aims to correct for PVE in order to improve the clinical assessment of [18F]Fluoride PET/CT imaging in presence of bone metastasis from prostate and breast cancer. In the second part of the project we develop a different PVC multiresolution approach aiming to improve the quantification of [11C]PIB PET/MR brain myelin imaging in Multiple Sclerosis (MS) patients. The algorithms validation was performed using either phantom data or clinical images of human controls. The main result of this work is that application of the PVC methodology resulted in a very significant gain in image resolution without any detectable increase of image noise. Lesions sharpness and detectability improved as well with a resulting increase in quantification accuracy. The algorithms developed and presented in this thesis proved to be straightforward tools to improve PET quantification in routine clinical practice.
25
Evans, Mark Julian. "The use of diffuse field measurements for acoustic emission." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267787.
Повний текст джерела
26
Hashim, K. I. "A study of crystal growth by field emission microscopy." Thesis, Bangor University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380230.
Повний текст джерела
27
Moghisi, M. "Ultrasonic and acoustic emission studies of plasma sprayed coatings." Thesis, University of Bath, 1985. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332455.
Повний текст джерелаАнотація:
This work assesses the potentials of two NDE techniques namely ultrasonic C-scan and acoustic emission for evaluating plasma sprayed coating quality. The coating materials used were aluminium (Metco 54), alumina (Metco 105), molybdenum (Mob3) and self-fusing molybdenum (Mo5O5). It has been established that ultrasonic C-scan imaging can reliably detect thickness variations of the order of 0.05mm in plasma sprayed coatings. Also, by using this technique it is possible to detect the presence of delamination or lack of adhesion between the coating and substrate. Although it was only possible to produce aluminium and alumina coatings with artificially introduced adhesion defects, it has been shown that the presence of such defects in other coatings can also be detected. It has been established that an ultrasonic C-scan technique is not sensitive to the process parameters of plasma spraying. The process parameters investigated were; poor surface preparation, input power and surface cooling. Another major limitation of ultrasonic C-scan technique is the geometrical restrictions where components with high curvatures can not be tested. Acoustic emission activities from plasma sprayed coatings were monitored during four point bend testing. Samples sprayed on poorly prepared surfaces or sprayed without coolant air could be distinguished from control samples using AE characteristics at low strain levels. Also the AE response of the alumina coatings reflected the thickness of the coatings. Thicker coatings produced more AE events. The AE response of the molybdenum (Mo63) and self-fusing molybdenum (Mo5O5) coatings were complex. It was found that they were related to the residual stresses in the coatings. Aluminium coatings showed very little acoustic emission activities.
28
Khalilzadeh, Rezaie Farnood. "Infrared emission spectroscopy of hot carbon monoxide." Master's thesis, University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4952.
Повний текст джерелаАнотація:
Gas giant exoplanets known as hot Jupiters orbit close to their parent stars and are heated to high temperatures. Their infrared spectra, measured by photometry during secondary eclipses, are dominated by carbon monoxide and methane, the principle reservoirs of carbon on these planets. The relative CO and CH[sub4] abundances inform us about temperature and pressure conditions and also about mixing by global winds driven by intense but asymmetric heating for these tidally locked bodies. Emission spectra collected during secondary eclipses, as the hot Jupiter passes behind its parent star, in principle allows a determination of the CO:CH[sub4] concentration ratio. Since hot Jupiters exist at temperatures of order 700 K, accurate model atmospheres require high temperature line lists for relevant molecules, for which existing data bases are apparently incomplete. Since the outer atmospheres of hot Jupiters are bombarded by intense ultraviolet radiation and energetic particles, there may even be a significant degree of ionization and non-equilibrium populations among the various molecular levels. Here we present high temperature emission spectra of CO obtained from a microwave discharge plasma, where the source of CO was carbon dioxide that dissociates under microwave heating. The spectrum was measured in the range 1800-2400 cm[super-1] at a resolution of 0.1 cm[super-1]. Vibrational transitions originating in up to the 13th vibrational level of the X [super1]greek upper case letter sigma][super+] ground electronic term were observed. From the J values for maximum intensity lines within the rotational fine structure, we obtain a temperature estimate of ~700 K, which is comparable to the atmospheric conditions of hot-Jupiters.ID: 030423212; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (M.S.)--University of Central Florida, 2011.; Includes bibliographical references (p. 79-80).
M.S.
Masters
Physics
Sciences
29
Ruckstuhl, Andreas Franz. "Analysis of the T₂ emission spectrum by robust estimation techniques /." Zürich, 1995. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=11170.
Повний текст джерела
30
Guthrie, Daniel K. "Analysis of quantum semiconductor heterostructures by ballistic electron emission spectroscopy." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/14915.
Повний текст джерела
31
Lee, Bong Jae. "Fabrication and Analysis of Multilayer Structures for Coherent Thermal Emission." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19839.
Повний текст джерелаАнотація:
This dissertation describes a theoretical and experimental study on coherent thermal emission from thin-film multilayer structures. A novel multilayer structure consisting of a one-dimensional photonic crystal and a polar material (or a metal) is proposed as a coherent thermal-emission source. Surface electromagnetic waves can be excited at the edge of photonic crystal, enabling coherent emission characteristics (i.e., spectral- and directional-selectivity in the emissivity). A near-infrared coherent emission source is designed and fabricated using vacuum deposition and chemical vapor deposition techniques. Measurements were performed using a Fourier-transform infrared spectrometer and a laser scatterometer. The agreement between the resonance conditions obtained from experiments and the calculated dispersion relation confirms that surface waves at the photonic crystal-metal interface can be utilized to build coherent thermal-emission sources. The second part of this dissertation focuses on the energy propagation direction in near-field thermal radiation. The energy streamline method based on the Poynting vector is applied to near-field thermal radiation by incorporating the fluctuational electrodynamics, in which thermal emission is viewed as originated from random motion of electric dipoles at temperatures above absolute zero. It is shown that the Poynting vector is decoupled for each parallel wavevector component due to the randomness of thermal emission. The spectral radiative energy travels in infinite directions along curved lines; this is a fundamental characteristic of near-field thermal radiation. The findings in this dissertation are important for the design of near-field optical sensors and energy conversion devices.
32
Viskovic, Verena. "Equilibrium analysis of carbon emission caps in regional electricity markets." Thesis, University College London (University of London), 2018. http://discovery.ucl.ac.uk/10057422/.
Повний текст джерелаАнотація:
This thesis uses state-of-the-art equilibrium models to analyse the impact of cap-and-trade (C&T) systems on regional electricity markets, which span areas subject to disparate carbon-reduction policies, e.g., only one area of the market is covered by a C&T. Such markets are vulnerable to carbon leakage, i.e., emission increase in the uncapped subregion as a result of imposing a C&T in the regulated subregion. Specifically, the focus is on the South-East Europe Regional Electricity Market (SEE-REM) for which an ex ante analysis of potential leakage into the non-EU ETS part is carried out considering the interaction of (i) an emission cap and hydropower availability and (ii) an emission cap and market power. In a perfectly competitive setting, a mixed-complementarity problem calibrated to SEE-REM is implemented for various C&T emission caps in order to estimate the extent of carbon leakage. The impact of market power is next incorporated using a bi-level model that is reformulated as a mathematical program with equilibrium constraints and implemented as a mixed-integer quadratic problem for SEE-REM in order to investigate how a dominant firm’s incentives to manipulate both electricity and carbon prices affect carbon leakage. Furthermore, in a theoretical framework, a bi-level model is developed where at the upper level, the policymaker determines an optimal emission cap over a subregion of an electricity market interconnected to the uncapped subregion. The purpose of this model is to establish the basis for a second-best anti-leakage measure.
33
Faisal, Nadimul Haque. "Acoustic emission analysis for quality assessment of thermally sprayed coatings." Thesis, Heriot-Watt University, 2009. http://hdl.handle.net/10399/2295.
Повний текст джерелаАнотація:
This study describes a new approach to the quality assessment of thermally sprayed carbide and ceramic coatings produced by High Velocity Oxy-Fuel (HVOF) and Air Plasma Spray (APS) processes. The aim of the work was to develop an experimental methodology based on Acoustic Emission (AE) monitoring of a dead-weight Vickers indentation to assess the degree of cracking and hence the toughness of the coating. AE monitoring was also applied to an industrial process as a contribution to the possibility of quality assessment during the deposition process. AE data were acquired during indentation tests on samples of coating of nominal thickness 250-325 μm at a variety of indentation loads ranging from 49 to 490 N. Measurements were carried out on six different thick-film coatings (as-sprayed HVOFJP5000/ JetKote WC-12%Co, HIPed HVOF-JetKote WC-12%Co, as-sprayed HVOFJP5000 WC-10%Co-4%Cr, conventional powder APS-Metco/9MB Al2O3 and fine powder HVOF-theta gun Al2O3) and also on soft and hard metallic samples and metals. The raw AE signals were analysed along with force and displacement history and the total surface crack length around the indent determined. Also, a selection of the indents was sectioned in order to make some observations on the sub-surface damage. The results show characteristic AE time evolutions during indentation for tough metals, hard metals, and carbide and ceramic coatings. Within each category, AE can be used as a suitable surrogate for crack length measurement for assessing coating quality. Finally, a preliminary observation on AE monitoring during HVOF (JP5000) WC- 10%Co-4%Cr thermal spraying was made. It was found that AE is sensitive to individual particle landings during thermal spraying and therefore can, in principle, be used to monitor the spray process.
34
Jack, Andrew G. "Total emission analysis of sewerage systems and wastewater treatment plants." Thesis, Abertay University, 1999. https://rke.abertay.ac.uk/en/studentTheses/3a4ee741-9f14-47df-ab48-2759ca7c39f3.
Повний текст джерелаАнотація:
The proposed methodology to most effectively manage intermittent combined sewage discharges into urban watercourses in the UK is given in the Urban Pollution Management (UPM) manual. The method is based on the use of detailed computer models of the sewerage system, wastewater treatment plant and receiving watercourse. Solving intermittent discharge problems using UPM, often requires the installation of in-sewer storage tanks. However, recent research from Germany and elsewhere (e.g. Austria and Denmark) has shown that this type of solution may be of little benefit with respect to the total emissions discharged from the entire system, where emissions from both the Combined Sewer Overflows (CSOs) and the Wastewater Treatment Plant (WTP) are considered together. This is because, in certain situations, WTP efficiency can be compromised by the prolonged periods of dilute (low nutrients and substrate) inflows which can result from the draining down of in-sewer storage tanks. The earlier research in Germany and elsewhere has been concerned with long term total emissions (annual loads) and not the problems specific to individual sites, or the benefits and/or limitations of storage with respect to acute pollution. Thus the principal objective of the research described here has been to substantiate and quantify the total emission problem by means of detailed modelling, via an evaluation of the likely storage volumes which could give rise to total emissions problems for the Perth wastewater system. Following this, a general method has been developed to investigate and resolve total emission problems related to acute pollution effects. As WTP disruption due to flow dilution can last for a prolonged period after even a single rainfall event, computational simulation times need to be long enough to represent the delay in WTP performance returning to normal operating conditions. As long term continuous simulation is usually impractical due to protracted computational times, a method referred to as the Total Emission Analysis Period (TEAP) has been developed. This will define the minimum required computational time and rainfall inputs to be used to ensure that the effect of in-sewer storage on total emissions could be modelled. Utilising the TEAP method to analyse total emissions it has been concluded that increasing volumes of storage would not be expected to create a total emission XXVI problem with respect to the Biochemical Oxygen Demand (BOD). Consequently, it was concluded that the best storage volume with respect to BOD was the minimum volume which would allow compliance with receiving water quality standards. No direct comparison could be made with the conclusion derived from the German research due to the long term nature of their analysis, however, it would appear from an interpretation of their results, that similar findings were obtained. With respect to ammonia, it was found that increases in total emissions can occur as, ammonia concentrations, unlike BOD, do not increase at the start of a storm due to first foul flush effects. Consequently, any increased emissions from the WTP would not be offset via a reduced CSO spill load. It was also found, however, that increasing volumes of storage would not be expected to exacerbate acute pollution problems within a receiving watercourse and that both large and small storage volumes had the potential to give rise to very similar degrees of WTP disruption. This was due to the way in which different hydraulic loading conditions (caused by the different volumes of storage) affected the bacterial concentrations in the reactor. The conclusion that storage would not provide a significant benefit for ammonia total emissions was supported by the Austrian and Danish research.
35
Girardello, Carlo. "Optical Analysis of Plasma : Flame Emission in Cryogenic Rocket Engines." Thesis, Luleå tekniska universitet, Rymdteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-76097.
Повний текст джерелаАнотація:
This thesis contains the results of optical flame emission measurements of the Vulcain 2.1engine and the plasma emission spectroscopy of the Lumen Project engine. The plume spectroscopyis analyzed, ordered and studied in detail to offer the best possible molecular composition.The main focus relied on the hydroxide radical, blue radiation and other moleculesanalysis of the intensities encountered during the tests. The plasma emission spectroscopy isfocused on the determination of the plasma temperature value in LIBS measurements. Thehydrogen plasma temperature determination of the local thermodynamic equilibrium, followedby the carbon and sequentially oxygen plasma is obtained. The quality of the LTE isto be determined to judge the truthworthness of the determined temperatures. Both the testsare analyzed thanks to the use of spectrographs, cameras and dedicated software for opticalapplications. The results related to the Vulcain 2.1 LOX/LH2 engine showed the evolutionof the plume in different ROF or pressure variations. Furthermore, the results of the LumenProject LOX/methane engine led to the determination of the plasma temperatures and a firstestimation of the LTE quality.Die vorliegende Arbeit präsentiert die Ergebnisse der Abgasstrahlspektroskopie des H2/LOXVulcain 2.1 Triebwerks und der Zündplasma Spektroskopie des CH4/LOX Triebwerks desLUMEN Projektes. Die Abgasstrahlspektroskopie wurde analysiert und im Detail untersuchtum die am besten passende molekulare Zusammensetzung herauszuarbeiten. DasHauptaugenmerk liegt dabei auf dem Hydroxyl- Radikal, der Blauen Strahlung und molekularerIntensitätsanalyse. Bei der Zündplasmaanalyse liegt der Fokus auf der Bestimmungdes LTE Zustands (Lokales thermodynamisches Gleichgewicht) in LIBS. Die Temperaturdes Wasserstoff-, Kohlenstoff und Sauerstoffplasmas wird herangezogen, um die Qualitätdes LTE Zustands zu beurteilen. Für die Testdurchführung wurden Spektrographen, Kamerasund bestimmte Auswertungstools für optische Anwendungen benutzt. Das Verhaltendes Vulcain 2.1 Abgasstrahls abhängig von verschiedenen ROF und Druckstufen ist in denErgebnissen beschrieben. Für das LUMEN Triebwerk konnten erste Zündplasmatemperaturenbestimmt werden und geben einen Rückschluss auf die Qualität des LTE.
36
Wirsz, Douglas Franklin. "Applications of multivariate methods to inductively coupled plasma optical emmission spectra." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/25070.
Повний текст джерелаАнотація:
The utility of multivariate analysis methods for the qualitative and quantitative analysis of complex ICP optical emission spectra is shown. A photodiode array is used to collect data which are simplified to a low resolution (approx. 4 A) spectrum for a number of knowns and unknowns. The digitized spectra thus obtained are plotted as points in multivariate space (pattern space). The spectra of different elements appear in well defined regions of pattern space. Qualitative analysis is accomplished by methods of cluster analysis and factor analysis. Quantitative analysis is carried out using multidimensional working curves. The pattern space coordinate system is transformed to give axes corresponding directly to elemental concentrations, allowing direct simultaneous determination of elemental composition. The effect of line intensities, detector dynamic range, and matrix effects are also discussed.Science, Faculty of
Chemistry, Department of
Graduate
37
Li, Jia Zheng. "A comparison of the performance of a low voltage microprobe for two thermal field emitters." Full text open access at:, 1986. http://content.ohsu.edu/u?/etd,98.
Повний текст джерела
38
Shum, Pak W. "A critical analysis of the acoustic emmission technique for NDE of pressure vessels." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-09192009-040341/.
Повний текст джерела
39
Elghamry, Mohamed Hussein. "Performance and condition monitoring of reciprocating machines using acoustic emission." Thesis, Heriot-Watt University, 2000. http://hdl.handle.net/10399/1125.
Повний текст джерела
40
Aljets, Dirk. "Acoustic emission source location in composite aircraft structures using modal analysis." Thesis, University of South Wales, 2011. https://pure.southwales.ac.uk/en/studentthesis/acoustic-emission-source-location-in-composite-aircraft-structures-using-modal-analysis(6871e94b-6e94-4efd-b563-41b254ee27b4).html.
Повний текст джерелаАнотація:
The aim of this research work was to develop an Acoustic Emission (AE) source location method suitable for Structural Health Monitoring (SHM) of composite aircraft structures. Therefore useful key signal features and sensor configurations were identified and the proposed method was validated using both artificially generated AE as well as actual AE resulting from damage. Acoustic Emission is a phenomenon where waves are generated in stressed materials. These waves travel through the material and can be detected with suitable sensors on the surface of the structure. These stress waves are attributed to propagating damage inside the material and can be monitored while the structure is in service. This makes AE very suitable for SHM, in particular for aircraft structures. In recent years composite materials such as carbon fibre reinforced epoxy (CFRP) are increasingly being used for primary and secondary structures in aircraft. The anisotropic layup of CFRP can lead to different failure mechanisms such as delamination, matrix cracking or fibre breakage which affects the remaining life time of the structure to different extents. Accurate damage location is important for SHM systems to avoid further inspections and allows for a maintenance scheme which considers the severity of the damage, due to damage type, extent and location. This thesis presents a novel source location method which uses a small triangular AE sensor array. The method determines the origin of an AE wave by a combination of time of arrival and modal analysis. The small footprint of the array allows for a fast and easy installation in hard-to-reach areas. The possibility to locate damage outside and at a relatively far distance from the array could potentially reduce the overall number of sensors needed to monitor a structure. Important wave characteristics and wave propagation in particular in CFRP were investigated using AE simulated by an artificial source and actual damage in composite specimens.
41
Bai, Wenjia. "Respiratory motion correction in positron emission tomography." Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:f73b144d-5287-4600-8b82-74229dc0eb31.
Повний текст джерелаАнотація:
In this thesis, we develop a motion correction method to overcome the degradation of image quality introduced by respiratory motion in positron emission tomography (PET), so that diagnostic performance for lung cancer can be improved. Lung cancer is currently the most common cause of cancer death both in the UK and in the world. PET/CT, which is a combination of PET and CT, providing clinicians with both functional and anatomical information, is routinely used as a non-invasive imaging technique to diagnose and stage lung cancer. However, since a PET scan normally takes 15-30 minutes, respiration is inevitable in data acquisition. As a result, thoracic PET images are substantially degraded by respiratory motion, not only by being blurred, but also by being inaccurately attenuation corrected due to the mismatch between PET and CT. If these challenges are not addressed, the diagnosis of lung cancer may be misled. The main contribution of this thesis is to propose a novel process for respiratory motion correction, in which non-attenuation corrected PET images (PET-NAC) are registered to a reference position for motion correction and then multiplied by a voxel-wise attenuation correction factor (ACF) image for attenuation correction. The ACF image is derived from a CT image which matches the reference position, so that no attenuation correction artefacts would occur. In experiments, the motion corrected PET images show significant improvements over the uncorrected images, which represent the acquisitions typical of current clinical practice. The enhanced image quality means that our method has the potential to improve diagnostic performance for lung cancer. We also develop an automatic lesion detection method based on motion corrected images. A small lung lesion is only 2 or 3 voxels in diameter and of marginal contrast. It could easily be missed by human observers. Our method aims to provide radiologists with a map of potential lesions for decision so that diagnostic efficiency can be improved. It utilises both PET and CT images. The CT image provides a lung mask, to which lesion detection is confined, whereas the PET image provides distribution of glucose metabolism, according to which lung lesions are detected. Experimental results show that respiratory motion correction significantly increases the success of lesion detection, especially for small lesions, and most of the lung lesions can be detected by our method. The method can serve as a useful computer-aided image analysing tool to help radiologists read images and find malignant lung lesions. Finally, we explore the possibility of incorporating temporal information into respiratory motion correction. Conventionally, respiratory gated PET images are individually registered to the reference position. Temporal continuity across the respiratory period is not considered. We propose a spatio-temporal registration algorithm, which models temporally smooth deformation in order to improve the registration performance. However, we discover that the improvement introduced by temporal information is relatively small at the cost of a much longer computation time. Spatial registration with regularisation yields similar results but is superior in speed. Therefore, it is preferable for respiratory motion correction.
42
Sibbald, David Bruce. "Development of data acquisition and analysis methods for chemical acoustic emission." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/28829.
Повний текст джерелаАнотація:
Acoustic Emission Analysis (AEA) is the study of the sonic (and ultrasonic) energy released by chemical systems in the form of transient waves, as the system attempts to (re)attain equilibrium. This area of chemistry, and chemical analysis, is ripe for fundamental studies since it has been little explored. The high potential of the technique as a non-invasive, non-destructive reaction monitoring scheme suggests that numerous applications will follow.
In this work, an apparatus and software have been constructed to monitor acoustic emission (AE) and collect and process AE data. A broad-band piezoelectric transducer was used to convert the acoustic signals to electrical waveforms which could be captured by a digital storage oscilloscope. These waveforms were then stored on an IBM-compatible computer for further analysis.
Analysis of the data was performed using pattern recognition techniques. The signals were characterized through the use of descriptors which can map each signal onto a multi-dimensional feature space. Visualization of the data structure in multidimensional
space was accomplished using several methods. Hierarchical clustering was used to produce tree structures, known as dendrograms, which attempt to show clustering of the signals into various groups. Abstract factor analysis (AFA) - also called principal components analysis (PCA) - was used to project the data onto a two dimensional factor space to allow for direct viewing of structure in the multidimensional
data.
Sodium hydroxide dissolution, aluminum chloride hydration and heat activation of Intumescent Flame Retardants (IFR's) were used to test the assembled hardware and to provide data to submit to the pattern recognition algorithms coded as part of this
work. The solid-solid phase transition of trimethylolethane (Trimet), and the liquid crystal phase transitions of two liquid crystals (α-ѡ-bis(4-n-decylaniline-benzilidene-4'-oxyhexane), and 4-n-pentyloxybenzylidene-4'-n-heptylaniline) were also monitored and the signals analyzed.
The pattern recognition software was able to extract much information from the acoustically emitting samples - information which would not have been apparent by using standard (uni- and bi-variate) methods of analysis. Chemical acoustic emission, coupled with pattern recognition analysis, will be able to provide the chemist with knowledge (qualitative, quantitative, kinetic, etc.) about chemical systems which are often difficult or impossible to monitor and analyze by other means.Science, Faculty of
Chemistry, Department of
Graduate
43
Calnan, Peter John Courtney Benedict. "Analysis of new engine cycles for spark ignition engines." Thesis, Brunel University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389985.
Повний текст джерела
44
Zaman, Abdul. "Implementation and Performance Analysis of Information Communication between Traffic Simulation and Emission Estimation Systems." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-120229.
Повний текст джерелаАнотація:
Transport är en av de snabbt växande områden och i direkt samband med den sociala ekonomiska tillväxten i ett land. Och samtidigt är det en av de största källorna till utsläpp produktion, som har en enorm påverkan på den globala miljön och alla levande varelser. För närvarande använder metoder för skattning av utsläpp är mycket dyra och endast använda en eller två gånger per år. Men vi kan beräkna utsläppen i realtid med hjälp av trak simulator tillsammans med uppskattning system. Målet med detta examensarbete är att utveckla prestanda effektiv kommunikationsplattform mellan KTH-TPMA trak simulator och uppskattning för att mäta online utsläpp. För att bygga upp den kommunikationsplattform Olika simuleringsmodeller, arkitektur av KTH-TPMA trak simulator (dvs objekt hierarki och relationer, olika objekt interaktioner modeller händelse hantering mekanismen, och objektet uppdatera huvudmän), kommunikation middleware för heterogena miljöer, och olika uppskattning modeller studeras och undersökas. Meddelandet plattform genomförs med hjälp av CORBA och SOA (dvs. Web Service). I CORBA, synkron och asynkron (dvs uppskjutna synkron) kommunikationsmetoder genomförs. Traken simulator kan utbyta information på tre olika sätt, det vill säga enskilda, insamling och tråd meddelande lägen. För att ta reda på det optimala sättet mellan dessa två ansökningar olika fordon efterfrågan och vägnätet kongurationer används för att mäta kommunikation temne. Och utvärdera dessa kommunikation gånger för att ta reda på effektiv kommunikation metod. Efter utvärdering nner vi att CORBA asynkron kommunikation är det mest effektiva avseende på fjärrkontrollen meddelande temne. Men synkron kommunikation är bättre för exakt utsläppsvärdet.Transportation is one of the rapidly developing elds and directly connected with the social economic growth of a country. And at the same time, it is one of the major sources of emission production, which has an enormous impact in the global environment and all the living beings. Currently using emission estimation methods are very expensive and use only once or twice a year. But we can estimate emission in real time by using trafc simulator along with the emission estimation systems. The goal of this thesis is to develop performance efcient communication platform between the KTH-TPMA trafc simulator and the emission estimation systems to measure the online emission. To build up the communication platform different trafc simulation models, architecture of the KTH-TPMA trafc simulator (i.e., object hierarchy and relationships, different object interactions models, event handling mechanism, and the object update principals), communication middleware for heterogeneous environments, and different emission estimation models are studied and investigated. The communication platform is implemented using CORBA and SOA (i.e., Web Service). In CORBA, synchronous and asynchronous (i.e., deferred synchronous) communication methods are implemented. The trafc simulator can exchange the information in three different ways, i.e., individual, collection, and thread communication modes. To nd out the optimum communication method between these two applications different vehicle demand and road network congurations are used to measure the communication time. And evaluate these communication times to nd out the efcient communication method. After evaluation, we nd that the CORBA asynchronous communication is the most efcient respect to remote communication time. But synchronous communication is better for precise emission value.
45
Agerhäll, Isabella, Malin Kindmark, and Cecilia Stern. "Towards Climate Neutral Facility Management : Improved Greenhouse Gas Emission Calculations for Ihus." Thesis, Uppsala universitet, Institutionen för samhällsbyggnad och industriell teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-413768.
Повний текст джерелаАнотація:
Uppsala municipality has set a goal in line with the UN’s 2030 Agenda for sustainable development to be fossil-free by 2030. To achieve this a lot of local companies have signed the Uppsala Climate Protocol. One of these companies is the municipal facility management company AB Uppsala Kommun Industrihus, Ihus. This project aimed to help Ihus map their emissions connected to facility maintenance and management and to enable them to reach their goal of becoming climate neutral by 2030. The daily facility management was split up into the categories gardening, ventilation and installation, cleaning and facility work, materials and products, renovations, and painting. A sustainability spend analysis was performed on Ihus’ organisation and emissions per spent MSEK were calculated for each category by researching Ihus’ suppliers. By using those emission intensities, the two categories with the highest emissions could be identified as renovations and materials and products with intensities of 84.48 and 57.56 tonnes CO2e/MSEK, respectively. The remaining categories all had intensities below 3 tonnes CO2e/MSEK. Sensitivity analyses were performed on the results by tweaking the values of which the emissions were based on. The results showed that to lessen Ihus’ climate impact the areas of improvement are life cycle assessments for their facilities and overseeing transports.
46
Morrell, Claire. "FTIR emission studies of chemical processes." Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326026.
Повний текст джерела
47
Wang, Liang. "Analysis of Galvanized Steel Plates Using Glow Discharge-Atomic Emission Spectrometry." TopSCHOLAR®, 1999. http://digitalcommons.wku.edu/theses/762.
Повний текст джерелаАнотація:
Combining an intense emission source and a high-speed sputtering source in one, glow discharge atomic emission spectrometer (GD-AES) provides an efficient technique for analyzing surfaces, coatings and bulk solids. The purpose of our work is to explore the optimum lamp operation parameters of SA-2000 for analysis of galvanized steel plate and to investigate the method for qualitatively and quantitatively analyzing the zinc coating. Under the optimum experimental conditions found in our study, which are current of 19-21 mA; voltage of 900-1200 V; pressure 2.0-2.5 torr, the calibration curve is constructed, so that specific zinc concentration can be assign to the exact depth position in the sample. Several galvanized steel plate samples are tested and the thickness of coating and distribution of zinc in different depth of the coating are calculated on the basis of calibration curve. The above results are further analyzed to prove the reproducibility of the proposed method.
48
Klyuzhin, Ivan S. "Deformable motion correction and spatial image analysis in positron emission tomography." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/60277.
Повний текст джерелаАнотація:
Positron emission tomography (PET) is a molecular imaging modality that allows to quantitatively assess the physiological function of tissues in-vivo. Subject motion during imaging degrades the quantitative accuracy of the data. In small animal imaging, motion is minimized by the use of anesthesia, which interferes with the normal physiology of the brain. This can be circumvented by imaging awake rodents; however, in this case correction for non-cyclic motion with rigid and deformable components is required. In the first part of the thesis, the problem of motion correction in PET imaging of unrestrained awake rodents is addressed. A novel method of iterative image reconstruction is developed that incorporates correction for non-cyclic deformable motion. Point clouds were used to represent the imaged objects in the image space, and motion was accounted by using time-dependent point coordinates. The quantitative accuracy and noise characteristics of the proposed method were quantified and compared to traditional methods by reconstructing projection data from digital and physical phantoms. A digital phantom of a freely moving mouse was constructed, and the efficacy of motion correction was tested by reconstructing the simulated coincidence data from the phantom. In the second part of the thesis, novel approaches to PET image analysis were explored. In brain PET, analysis based on the tracer kinetic modeling (KM) may not always be possible due to the complexity of the scanning protocols and inability to find a suitable reference region. Therefore, the ability of KM-independent shape and texture metrics to convey useful information on the disease state was investigated, based on an ongoing Parkinson's disease study with radiotracers that probe the dopaminergic system. The pattern of the radiotracer distribution in the striatum was characterized by computing the metrics from multiple regions of interest defined using PET and MRI images. Regression analysis showed a significant correlation between the metrics and clinical disease measures (p<0.01). The effect of the region of interest definition and texture computation parameters on the correlation was investigated. Results demonstrate that there is clinically-relevant information in the tracer distribution pattern that can be captured using shape and texture descriptors.Science, Faculty of
Physics and Astronomy, Department of
Graduate
49
Aznar, Marianne. "Quantitative analysis of metabolic breast images from Positron Emission Mammography (PEM)." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0035/MQ50714.pdf.
Повний текст джерела
50
Brown, Elizabeth Ann. "Rapid aluminum alloy analysis utilizing inductively coupled plasma atomic emission spectrometry." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0030/MQ64327.pdf.
Повний текст джерела