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Laser Ablation - Inductively Coupled Plasma - Mass Spectrometry (LA-ICP-MS) is a powerful analytical technique for the direct elemental analysis of solid samples, with spatial resolution down to a few microns However, calibration remains the limiting factor in obtaining quantitative analysis by LA-ICP-MS for a wide range of sample types. No universal method exists as yet and the ones that are currently used tend to employ matrix-matched solid standards Matrix-matched solid standards are not available for many types of sample, such as polymers, biological materials, fluid inclusions, etc The need for a universal method of calibration that involves standards that are easy to prepare and suitable for any type of sample is required. Additional to matrix-matching, internal standards are widely used in LA-ICP-MS for quantitative analyses The internal standard compensates for the different ablation yields from the sample and the standard and for the laser shot to shot variation. Given that the use of an internal standard is required to obtain reliable results, the need for matrix-matching might be regarded as questionable This project has focused on the development and application of a new method of calibration for LA-ICP-MS. It involves the use of aqueous standards whose absorption characteristics are modified by the addition of a chromophore to the solution. Additives were selected for ablation with KrF excimer, and Nd.YAG lasers The influence of the additive concentration on the ablation yield was investigated for different laser energies. Response curves were obtained showing that as the additive concentration was increased, less energy was required to ablate the modified standard solutions efficiently. A general procedure was then defined for the preparation and use of the modified standard solutions for a given sample. The new method of calibration was used for the quantitative analysis of different sample types· low density polyethylene (LDPE), polyketone (PK), polyethylene thin film as well as gels contained in the thin film, and stainless steel. Investigations were carried out on the mechanism of ablation of the modified standard solutions. It appeared that the ablation proceeded by a three-step process leading ultimately to nebulisation of the bulk liquid.

The diesel engine is growing in popularity due to its energy efficiency and solving the emissions issues associated with diesel engine exhaust would clear the way for further growth. The key pollutants are NOx, particulate matter and unburned hydrocarbons. Selective catalytic reduction (SCR) catalysis is likely the best choice for NOx control. In SCR, NH3 selectively reacts with NOx to form N2 – the selectivity refers to NH3 reacting with NOx instead of the abundant O2. Urea is used as the NH3 source, being injected into the exhaust as an aqueous solution where the urea decomposes and NH3 is generated. Spatial resolution characterization techniques have been gaining attention in the catalysis field because of the higher level of information provided. In this thesis, a new spatial resolution technique, called SpaciFTIR (spatially-resolved, capillary-inlet Fourier transform infra-red spectroscopy), was developed, which overcomes the interference of water in the detection of NH3 in an earlier developed technique, SpaciMS (spatially-resolved, capillary-inlet mass spectrometry). With the new test method, three SCR topics were addressed. First, the three key SCR reactions were spatially resolved. These are the standard SCR reaction (2NO + 2NH3 + 1/2O2 = 2N2 + 3H2O), the fast SCR reaction (NO + NO2 + 2NH3 = 2N2 + 3H2O), and NO2-SCR, (6NO2 + 8NH3 = 7N2 + 12H2O). Results show that in the presence of NO2, but at a NO2/NOx ratio < 0.5, the fast SCR reaction proceeds followed by the standard SCR reaction, i.e. in series. If the NO2/NOx ratio exceeds 0.5, the NO2-SCR and fast SCR reactions occur in parallel. Compared to the standard integral test method, this spatial resolution technique clearly showed such trends. Secondly, the spatial resolution technique was used to characterize the effects of thermal aging on catalyst performance. It was found that for a highly aged catalyst, there was a radial activity profile due to an inhomogeneous temperature distribution in the process of aging. Aging effects on various key SCR reactions, i.e. NO oxidation, NH3 oxidation, and the reduction reactions, were studied. Last but not least, for the purpose of passive SCR system development, transient NH3 storage profiles along the monolith channel were measured with SpaciFTIR. Passive SCR is a system where the NH3 is generated on an upstream catalyst, such as a three-way catalyst or lean-NOx trap, instead of via urea injection. In such a system, NH3 is therefore not constantly being fed to the SCR catalyst, but “arrives” in pulses. Factors such temperature, NH3 concentration, pulsing time, flow rate and thermal aging were investigated. For the first time, NH3 migration was observed and its effect on SCR reactions along the length of catalyst was studied.

The automated Tree Identification and Delineation Algorithm (TIDA) was developed for application to high spatial resolution digital imagery of Australian native eucalypt forest. The algorithm is based on contiguous, threshold-based spatial clustering of pixels and was designed to cope with the complex asymmetric crowns typical of eucalypts. / To facilitate systematic algorithm evaluation, a forest scene simulation model was created for the simulation of visually realistic remotely sensed images. The model is based on the principles of ray-tracing and the geOll1etric description of scene objects and background. The model simulates the appearance of a forest scene viewed and illuminated from specific directions and under known atmospheric conditions. The distinctive 'modular' structure of eucalypts was represented by modelling crowns as small (branch-scale) spheroids distributed over a larger spheroidal envelope. / Using the simulation model, TIDA performance was evaluated in terms of forest structure (canopy cover, crown cover and canopy structural variability) and the remote sensing environment (view zenith angle, solar zenith angle and aerosol optical thickness). Prior to the evaluation, a methodology was developed for objectively estimating the optimum spatial resolution for TIDA application in a given image. The methodology was based on incremental Gaussian smoothing and exploited TIDA's sensitivity to changes in image spatial resolution. This process demonstrated the importance of individual crown cover, rather than crown size, as the main factor determining the optimum spatial resolution for tree delineation. / Results indicate that TIDA is most suited for application in forests with high canopy cover and high crown cover. The structural complexity of forest canopies, represented by the diameter and overlap of crowns and tree height, had a relatively small impact on TIDA performance. Increasing view zenith angle consistently caused a decrease in TIDA performance. A small phase angle between the sun and sensor produces optimum TIDA performance when both canopy and crown cover is high. As crown or canopy cover decrease, high positive and negative sun zenith angles yield superior TIDA results by decreasing the brightness of the background relative to the canopy and improving the identification of tree peaks. For both dense and sparse canopies, back-scattered radiation from the forest canopy was more suited to automated tree crown delineation than forward-scattered radiation. Imagery acquired under an optically thick atmosphere was found to increase TIDA performance compared to scene illumination under strong direct light. The advantage stemmed from a strengthening of the relationship between geometric and radiometric crown shape. / Through an awareness of limitations imposed by the remote sensing environment, the potential for manipulation of image characteristics, and preferential selection of acquisition conditions, TIDA performance can be optimised to suit various structural forest types. Canopy cover, crown cover, view zenith angle, sun zenith angle, background brightness and image spatial resolution are key criteria in assessing the suitability of automated tree crown delineation as an image interpretation procedure.

Les méthodes standard de pansharpening visent à fusionner une image panchromatique avec une image multispectrale afin de générer une image possédant la haute résolution spatiale de la première et la haute résolution spectrale de la dernière. Durant la dernière décennie, beaucoup de méthodes de pansharpening utilisant des images multispectrales furent créées. Avec la disponibilité croissante d’images hyperspectrales, ces méthodes s’étendent maintenant au pansharpening hyperspectral, c’est-à-dire à la fusion d’une image panchromatique possédant une très bonne résolution spatiale avec une image hyperspectrale possédant une résolution spatiale plus faible. Toutefois les méthodes de pansharpening hyperspectrale issues de l’état de l’art ignorent souvent le problème des pixels mixtes. Le but de ses méthodes est de préserver l’information spectrale tout en améliorant l’information spatiale. Dans cette thèse, dans une première partie, nous présentons et analysons les méthodes de l’état de l’art afin de les analyser pour connaitre leurs performances et leurs limitations. Dans une seconde partie, nous présentons une approche qui s’occupe du cas des pixels mixtes en intégrant une étape pré-fusion pour les démélanger. Cette méthode améliore les résultats en ajoutant de l’information spectrale qui n’est pas présente dans l’image hyperspectrale à cause des pixels mixtes. Les performances de notre méthode sont évaluées sur différents jeux de données possédant des résolutions spatiales et spectrales différentes correspondant à des environnements différents. Notre méthode sera évaluée en comparaison avec les méthodes de l’état de l’art à une échelle globale et locale. / Standard pansharpening aims at fusing a panchromatic image with a multispectral image in order to synthesize an image with the high spatial resolution of the former and the spectral resolution of the latter. In the last decade many pansharpening algorithms have been presented in the literature using multispectral data. With the increasing availability of hyperspectral systems, these methods are now extending to hyperspectral pansharpening, i.e. the fusion of a panchromatic image with a high spatial resolution and a hyperspectral image with a coarser spatial resolution. However, state of the art hyperspectral pansharpening methods usually do not consider the problem of the mixed pixels. Their goal is solely to preserve the spectral information while adding spatial information. In this thesis, in a first part, we present the state-of-the-art methods and analysed them to identified there performances and limitations. In a second part, we present an approach to actually deal with mixed pixels as a pre-processing step before performing the fusion. This improves the result by adding missing spectral information that is not directly available in the hyperspectral image because of the mixed pixels. The performances of our proposed approach are assessed on different real data sets, with different spectral and spatial resolutions and corresponding to different contexts. They are compared qualitatively and quantitatively with state of the art methods, both at a global and a local scale.

Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2017-09-05T19:55:41Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) lomanto_zogaib_neves.pdf: 8358673 bytes, checksum: 9f42efc6634c0b49d194cc2a19630c84 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2017-09-18T17:00:26Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) lomanto_zogaib_neves.pdf: 8358673 bytes, checksum: 9f42efc6634c0b49d194cc2a19630c84 (MD5) / Made available in DSpace on 2017-09-18T17:00:26Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) lomanto_zogaib_neves.pdf: 8358673 bytes, checksum: 9f42efc6634c0b49d194cc2a19630c84 (MD5) Previous issue date: 2017 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / O Cerrado ? considerado um hotspot mundial de biodiversidade, por apresentar uma vasta abund?ncia de esp?cies end?micas que sofrem uma anormal perda de habitat. Al?m disso neste bioma h? importantes bacias hidrogr?ficas, cuja preserva??o das nascentes e leito dos rios e c?rregos ? de extrema necessidade. Com a finalidade de facilitar o estudo dessas ?reas a utiliza??o do Sensoriamento Remoto tornou-se uma excelente ferramenta. Assim, num primeiro momento, este trabalho utilizou imagens dos sensores dos sat?lites Landsat-5 e Landsat-8 para monitorar o desenvolvimento de ?reas de degrada??o, utilizando o ?ndice NDVI, na sub-bacia Hidrogr?fica do Ribeir?o Chiqueiro entre 1984 e 2016. No segundo momento verificou a aplicabilidade das imagens do sat?lite CBERS-4 na distin??o de diferentes tipos de vegeta??o e ou uso e ocupa??o do terreno, comparando-o com o sat?lite Landsat-8, e Rapideye-3, por meio do ?ndice NDVI e da diferen?a NDVI. Como resultados da primeira parte do trabalho foi poss?vel quantificar 108 vo?orocas na regi?o e atestar que a ?rea da sub-bacia sofreu grandes mudan?as nos anos estudados, principalmente com aumento expressivo do uso e ocupa??o do terreno. Nas ?reas de entorno das vo?orocas, que tinham como predomin?ncia tipos de vegeta??o com menor densidade de dossel, como cultura agropecu?rias (principalmente pasto), Campo limpo e Campo Sujo, verificou-se uma maior tend?ncia de crescimento dos vo?orocamentos. Na segunda parte do trabalho foi poss?vel verificar que, como j? era esperado, as imagens do sensor do sat?lite Rapideye, apresentaram melhor resolu??o, sendo seguidas pela imagem do sensor do sat?lite CBERS-4, que se mostrou vi?vel para uso em ?reas de Cerrado. Mesmo assim, estas s?o preteridas por imagens do sensor do sat?lite Landsat-8, que no presente trabalho obteve os piores resultados, deixando de identificar muitas diferen?as na vegeta??o. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Ci?ncia Florestal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2017. / The Cerrado is considered a global biodiversity hotspot due to the abundance of Endemic species that suffer a huge habitat loss. Besides in this biome there are important hydrographic basins, whose Preservation of springs, rivers and streams is of utmost importance. In order to facilitate the study of these areas, the use of Remote Sensing has become an excellent tool. Thus, in the first stage, this work used images from the Landsat-5 and Landsat-8 satellite sensors to monitor the development of degradation areas, using the NDVI index, in the sub-basin of Ribeir?o Chiqueiro between 1984 and 2016. In the second The results obtained in this study show the applicability of the CBERS-4 satellite images to the distinction between different vegetation types and or use and occupation of land, comparing it with the satellite Landsat-8 and Rapideye-3, using the NDVI index and the NDVI difference. As a result of the first part, it was possible to quantify 108 gullies in the region attesting that the sub-basin area underwent major changes in the years studied, mainly with a significant increase in use and occupation of land. In the areas surrounding the gullies, which had as predominant types of vegetation with lower canopy density, such as agricultural culture (mainly pasture), Campo Limpo and Campo Sujo, there was a greater tendency of vo?orocamentos growth. In the second part of the work, it was possible to verify that, as expected, the images of Rapideye satellite sensor presented better resolution and were followed by the CBERS-4 satellite image, which proved to be feasible for use in Cerrado areas. Even so, these are neglected by images of the Landsat-8 satellite sensor, which in the present work obtained the worst results, failing to identify many differences in vegetation.

A new multi-purpose surface analytical instrument (the Hallam instrument) is described, which combines the surface specific information obtained using x-ray photoelectron spectroscopy (XPS), with bulk information obtained using Energy Dispersive X-ray (EDX) detection. A 15kV electron gun and an ultra high vacuum EDX detector give the instrument an EDX mapping capability. To exploit this to its full potential, spatial alignment of EDX maps acquired at various electron beam energies, E[o], was required. The misalignment of images acquired at various E[o] values was investigated, and a means of describing the misalignment as a function of E[o] was presented. An algorithm was developed which would allow the alignment of offline images acquired at different E[o] values. This was demonstrated on images acquired on both the Hallam instrument and on a Phillips XL40 electron microscope. The small area XPS system developed by Kratos analytical gave a spatial resolution of 30pm at the centre of the field of view, although this deteriorated away from the centre. The reasons for this deterioration in spatial resolution were investigated, and two methods of improving the system were presented. The improvements were implemented on the Hallam instrument and demonstrated using a standard silver grid sample. The small area XPS was applied to a TiAINi coated stainless steel sample to demonstrate its application to real samples, and to display the spatial alignment between the XPS and EDX maps. Finally, the instrument was calibrated for quantitative XPS studies. This involves determining the response of the instrument as a function of the photoelectron kinetic energy. From several methods presented in the literature, the most appropriate was chosen for calibration of the 'Hallam' instrument. The effectiveness of the method used was assessed by recording spectrum intensity from pure elemental standards, and comparing the results with intensity values calculated using the calibration curves.

Unmanned aerial vehicles (UAV) have become an interesting and active research topic for photogrammetry. Current research is based on images acquired by an UAV, which have a high ground resolution and good spectral and radiometrical resolution, due to the low flight altitudes combined with a high resolution camera. UAV image flights are also cost effective and have become attractive for many applications including, change detection in small scale areas. One of the main problems preventing full automation of data processing of UAV imagery is the degradation effect of blur caused by camera movement during image acquisition. This can be caused by the normal flight movement of the UAV as well as strong winds, turbulence or sudden operator inputs. This blur disturbs the visual analysis and interpretation of the data, causes errors and can degrade the accuracy in automatic photogrammetric processing algorithms. The detection and removal of these images is currently achieved manually, which is both time consuming and prone to error, particularly for large image-sets. To increase the quality of data processing an automated process is necessary, which must be both reliable and quick. This thesis proves the negative affect that blurred images have on photogrammetric processing. It shows that small amounts of blur do have serious impacts on target detection and that it slows down processing speed due to the requirement of human intervention. Larger blur can make an image completely unusable and needs to be excluded from processing. To exclude images out of large image datasets an algorithm was developed. The newly developed method makes it possible to detect blur caused by linear camera displacement. The method is based on human detection of blur. Humans detect blurred images best by comparing it to other images in order to establish whether an image is blurred or not. The developed algorithm simulates this procedure by creating an image for comparison using image processing. Creating internally a comparable image makes the method independent of additional images. However, the calculated blur value named SIEDS (saturation image edge difference standard-deviation) on its own does not provide an absolute number to judge if an image is blurred or not. To achieve a reliable judgement of image sharpness the SIEDS value has to be compared to other SIEDS values of the same dataset. This algorithm enables the exclusion of blurred images and subsequently allows photogrammetric processing without them. However, it is also possible to use deblurring techniques to restor blurred images. Deblurring of images is a widely researched topic and often based on the Wiener or Richardson-Lucy deconvolution, which require precise knowledge of both the blur path and extent. Even with knowledge about the blur kernel, the correction causes errors such as ringing, and the deblurred image appears muddy and not completely sharp. In the study reported in this paper, overlapping images are used to support the deblurring process. An algorithm based on the Fourier transformation is presented. This works well in flat areas, but the need for geometrically correct sharp images for deblurring may limit the application. Another method to enhance the image is the unsharp mask method, which improves images significantly and makes photogrammetric processing more successful. However, deblurring of images needs to focus on geometric correct deblurring to assure geometric correct measurements. Furthermore, a novel edge shifting approach was developed which aims to do geometrically correct deblurring. The idea of edge shifting appears to be promising but requires more advanced programming.

The aim of this research is to explore the integration of ad hoc and mobile sensors into a conventional Electrical Resistance Tomography (ERT) system. This is motivated by the desire to improve the spatial resolution of 3D reconstructed images that are produced using ERT. The feasibility of two approaches, referred to as the Extended Electrical Tomography (EET) and Augmented Electrical Tomography (AET) are considered. The approaches are characterized according to the functionality of the sensors on the ad hoc 'pills'. This thesis utilizes spectral and numerical analysis techniques, with the goal of providing a better understanding of reconstruction limitations, including quality of measurements, sensitivity levels and spatial resolution. These techniques are applied such that an objective evaluation can be made, without having to depend heavily on visual inspection of a selection of reconstructed images when evaluating the performance of different set-ups. In EET, the sensors on the pills are used as part of the ERT electrode system. Localized voltage differences are measured on a pair of electrodes that are located on an ad hoc pill. This extends the number of measurements per data set and provides information that was previously unobtainable using conventional electrode arrangements. A standalone voltage measurement system is used to acquire measurements that are taken using the internal electrodes. The system mimics the situation that is envisaged for a wireless pill, specifically that it has a floating ground and is battery-powered. For the present exploratory purposes, the electronic hardware is located remotely and the measured signal is transmitted to the PC through a cable. The instrumentation and data acquisition circuits are separated through opto-isolators which essentially isolates both systems. Using a single pill located in the centre of a vessel furnished with 16 electrodes arranged in a single plane, spectral analysis indicates that 15 of the 16 extended measurements acquired using the adjacent current injection strategy are unique. Improvement is observed for both the sensitivity and spatial resolution for the voxels in the vicinity of the ad hoc pill when comparing the EET approach with the conventional ERT approach. This shows the benefit of the EET approach. However, visual inspection of reconstructed images reveals no apparent difference between images produced using a regular and extended dataset. Similar studies are conducted for cases considering the opposite strategy, different position and orientation of the pill, and the effect of using multiple pills. In AET, the sensors on the ad hoc pills are used as conductivity probes. Localized conductivity measurements provide conductivity values of the voxels in a discretized mesh of the vessel, which reduces the number of unknowns to be solved during reconstruction. The measurements are incorporated into the inverse solver as prior information. The Gauss-Newton algorithm is chosen for implementation of this approach because of its non-linear nature. Little improvement is seen with the inclusion of one localized conductivity measurement. The effect on the neighbouring voxels is insignificant and there is a lack of control over how the augmented measurement influences the solution of its neighbouring voxels. This is the first time that measurements using ad hoc and 'wireless' sensors within the region of interest have been incorporated into an electrical tomography system.

Current research in CI combustion aims to reduce PM and NOx emissions by controlling mixture homogeneity. Low CN fuels are suitable due to their auto-ignition resistance, but the in-cylinder mixture stratification level must be carefully visualised and controlled. Numerous diagnostic techniques exist for imaging the in-cylinder hydrocarbon species concentration. Tomographic techniques based on spectroscopic modalities are minimally-intrusive and able to target species of interest even in multi-component fuel blends. The high-speed CST technique applied in this work is based on the NIRAT modality. A number of collimated LASER beams at 1700nm traverse the optically accessible engine combustion chamber and are spectroscopically absorbed by the first overtone of the C-H stretch bond. Non species-specific attenuation mechanisms are suppressed by a DWR scheme utilising a reference wavelength at 1651nm. Ratiometric data is used to tomographically reconstruct the spatially-varying fuel concentration. In this work the first application of NIRAT on a commercial CI engine is presented, using instrumentation capable of imaging 13 frames/CAD at 1200rpm using a 31-beam array. A novel method was developed to experimentally quantify the tomography system’s non-uniform spatial resolution. The method was applied in laboratory experiments involving free-space propane plumes and a map of the spatial resolution was created. The spatial resolution varies between 4mm and 14mm. The mean of 9mm is 72% better than previous estimates in the literature. Regions of poor performance correlated with non-uniformities in the sensitivity matrix, indicating that a regular beam array may contribute towards more accurate and objective reconstructions of unknown concentrations. The characterised tomography system was installed on an optically-accessible Volvo D5 CI engine. The optically-inaccessible CAD region achieved was ±18CAD, a reduction of ±12° from previous works. The vibration-tolerance of the optical access system was verified, concluding that the initial alignment of the beams is the dominant factor that determines beam integrity after prolonged engine operation. The behavior of individual beams was studied, finding strong cycle-to-cycle correlation of the anomalies present. This was exploited to develop a novel, robust analysis algorithm to process the engine data. The algorithm achieved a standard deviation of <10% of the maximum pk-pk magnitude of the transmission signal in the fuel vapour phase. The system was applied to qualitatively visualise the mixing of a 50/50% blend of iso-/n-dodecane in a motored, nitrogen-aspirated engine under a range of operating conditions. A study by simulation of the decomposition of n-dodecane concluded that only 0.492% of the quantity injected is pyrolytically converted during a compression stroke. Spray-phase imaging was not possible due to severe reduction of the optical throughput, lasting for 8-15 CAD for a lean mixture and for 15-30 CAD for a rich mixture. Vapour-phase reconstructions using the enhanced iterative Landweber algorithm were successful in resolving rich fuel pockets consistent with the injection pattern. It was shown that the degree of mixture homogeneity at TDC is dependent upon the initial intake temperature. PLIF was used to cross-validate the NIRAT reconstructions. Localisation of the features reconstructed with NIRAT was excellent, with a maximum angular deviation of ±10°. A swirl motion of the mixture by 1°/CAD was observed using both techniques, confirming the features previously observed in the NIRAT reconstructions. In conclusion, NIRAT has been, for the first time, successfully applied for in-cylinder fuel distribution imaging in a CI engine. The results, created using an original data analysis algorithm, were successfully cross-validated using PLIF. A novel spatial resolution quantification method was formulated and used to characterise the tomography system. The numerous findings and learning points from the individual stages of this work will be used to advance the field of combustion diagnostics as well as contribute towards the development of advanced in-cylinder tomographic imaging systems.