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Gul-E-Saman. "Surface analysis using polarisation." Thesis, University of York, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.583351.
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Unpolarised light incident on a surface acquires partial polarisation due to the orientation of the dipoles in the scatterer. This thesis focuses on the use of polarised light for diffuse reflectance for surface analysis. Since, the state of polarisation is acquired on interaction with the surface, the polarised light contains information about the surface properties (of the scatterer). A great amount of research has been carried out in computer vision for surface analysis using image analysis techniques. Recently, the trend has been to combine optical techniques with computer vision in order to arrive at better analysis techniques by methods that analyse the intrinsic qualities of the surfaces under study. An overview of the recent work that has been carried out in the field is given in Chapter 2 in context to this thesis. The contributions of this thesis are: 1. the robust computation of polarisation image using M-estimators, the smoothing of phase of polarisation by using directional statistics and using the calculated parameters for effective surface recovery, 2. estimation of the refractive index of a diverse set of surfaces of known and unknown refractive indices and using the estimates for segmentation, 3. estimating the complex refractive index which incorporates the phenomenon of absorption by two methods existing in literature, using a. ellipsometry and b. multiple polarisation measurements while building up on the case of surface analysis being related to its optical properties and 4. carrying out a preliminary study by modifying the geometric factor of the polarimetric bidirectional reflectance distribution function. Experimental evidence has been presented in the thesis for the methods that have been used for a variety of objects with varying geometrical and surface properties. The approach in this thesis has been to adopt simple and adaptable techniques that can be easily employed without the use of sophisticated equipment.
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Lund, Christopher Paul. "Surface spectroscopy and Auger lineshape analysis studies of amorphous silicon surfaces." Thesis, Lund, Christopher Paul (1993) Surface spectroscopy and Auger lineshape analysis studies of amorphous silicon surfaces. PhD thesis, Murdoch University, 1993. https://researchrepository.murdoch.edu.au/id/eprint/42221/.
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This work deals with the experimental investigation of the surface of one of the most interesting and important new semiconductor materials, hydrogenated amorphous silicon (a-Si:H). Ultra-high vacuum surface spectroscopy methods, especially Auger lineshape analysis and X-ray photoelectron spectroscopy (XPS), have been used with a view to studying the effect on the local densities of states at the surface of various preparation methods and subsequent treatments.
X-ray excited Si L2,3VV and Si L1L2,3V Auger lines as well as XPS valence band (XPS VB) spectra have been measured for a number of silicon materials and surfaces prepared in different ways. These materials included crystalline silicon (c-Si), amorphous silicon (a-Si) and hydrogenated amorphous silicon (a-Si:H). Preparation techniques used included atmospheric pressure chemical vapour deposition (APCVD), glow discharge (GD) or plasma enhanced CVD and radio frequency (RF) sputtering. Surface treatments included disordering of c-Si by argon ion bombardment, hydrogenation by hydrogen ion bombardment, annealing and rehydrogenation from the bulk.
Methods have been developed and thoroughly tested to enable X-ray excited silicon Auger spectra to be treated routinely using numerical debroadening and deconvolution to obtain an indication of the valence band transition densities of states (VBTDOS). These show good agreement with previously published results for electron initiated Auger spectra and theoretical results. In particular a method has been developed for treating the experimentally difficult Si L1L2,3V Auger line. Techniques have been developed to remove the sloping background and Coster-Kronig broadening to enable an indication of the transition densities of states. The L1L2,3V derived VBTDOS approximates closely to the theoretical DOS and the experimental results obtained from UPS and XPS. It is shown that because of this the Si L1L2,3V line is a more effective method of monitoring changes in the surface VBTDOS of a-Si:H due to various treatments than the more commonly used but harder to interpret Si L2,3VV line.
A method based on the simplex algorithm has been applied to enable the Si L2,3VV and Si L1L2,3V spectra to be decomposed (decoupled) into their component (p-, sp- and s/L2H like) peaks. Changes in the relative contributions of these components have been compared with changes induced by disordering and hydrogenation. It is shown that both the Si L2,3VV and Si L1L2,3V lines give a semiquantitative method for monitoring hydrogen incorporation and changes in the localised states near the valence band edge. Results are presented for varying amounts of disorder (or amorphousness) produced by argon ion bombardment of the surface. A number of results are ·presented· for artificial and naturally hydrogenated surfaces as well as for different deposition techniques.
AES and XPS are shown to be very sensitive to changes in disorder (amorphousness) and hydrogen bonding in a-Si:H. The L1L2,3V Auger spectrum is found to be particularly sensitive. Both the AES and XPS VB spectra for a disordered c-Si sample give new information on the affect of disorder on the DOS. The L1L2,3V Auger line is also shown to be sensitive to varying degrees of disorder. Si L2,3VV and L1L2,3V spectra are successfully used to study the effect of several rehydrogenation methods on a-Si. These methods are shown to lead to different amounts of hydrogen in the surface as well as differences in the type of hydrogen bonding. A-Si:H prepared using different techniques is shown to have differences in the amount of order and hydrogen present in the films produced. The deposition technique is also seen to effect the type of hydrogen bonding present in the surface.
A novel transfer vessel has been constructed to enable samples prepared in one system to be analysed in another UHV system without exposure to air and the subsequent contamination of the surface. Results are presented for a pure, 'as deposited' surface of a-Si:H prepared by GD. The 'as deposited' surface is shown to be significantly different to one that has been argon ion cleaned and then rehydrogenated. Also using the transfer method changes in the Si L1L2,3V, Si L2,3VV and XPS VB spectra were studied for an a-Si:H surface after heating above the first desorption threshold for hydrogen. This enables the effect of different Si-H bonding configurations on the VBDOS to be studied.
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Perkins, John Bigelow Jones Lawrence R. "Surface ship overhaul decision analysis." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1992. http://handle.dtic.mil/100.2/ADA260623.
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Duncan, S. "Ion erosion in surface analysis." Thesis, Loughborough University, 1985. https://dspace.lboro.ac.uk/2134/28023.
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Low energy ion bombardment is a process used in surface analysis and in the electronics and telecommunications industries. Techniques such as Auger Electron Spectroscopy (AES), X-ray Photoelectron Spectroscopy (XPS) and Secondary Ion Mass Spectroscopy (SIMS) employ ion bombardment for surface cleaning and for the provision of composition-depth profiles.
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LaBute, Gerard Joseph. "Pseudo-Bayesian response surface analysis." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0001/MQ34971.pdf.
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Taylor, Michael. "Surface analysis of polymer microarrays." Thesis, University of Nottingham, 2009. http://eprints.nottingham.ac.uk/10717/.
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Polymers have been used as biomaterials for nearly a century and have recently become the material of choice for use in tissue engineering. However, the classes of biodegradable and biocompatible polymers available for use in biomedical devices and as tissue engineering scaffolds are limited. This lack of available polymers with suitable properties could inhibit the development of biomedical devices with improved biocompatibility and hinder the growth of the fledgling tissue engineering field. Researchers in the polymer and biomaterials fields have tried to remedy this problem by applying combinatorial and high throughput methods developed in drug discovery to the search for new polymers. A recent advance has been the development of combinatorial polymer libraries printed as microarrays. This format allows the polymers to be readily screened for their cell adhesion and differentiation properties, allowing ‘hit’ materials with ideal properties to be identified. However, without knowledge of the surface properties of these novel polymers it is impossible to rationalise their biological properties. The surface characterisation of such microarrays presents numerous practical problems included small sample size, sample number and even analysis of such large amounts of data. It is the aim of this thesis to develop methods for the characterisation of the surface chemistry, wettability and protein adsorption properties of polymers in situ in microarray format and within realistic timeframes. The thesis will explore multivariate statistics in the form of PCA and PLS as methods of analysing the large amount of data acquired. The first part of this thesis describes the surface chemical analysis of a polymer microarray using ToF-SIMS and XPS. A comparison of the polymers’ surface to bulk chemistries by XPS indicated that 64 % of the polymers had a surface chemistry which differed from the bulk. This reinforces the need for characterisation of the polymers’ surface chemistries, as it is obvious that this can not be inferred from their bulk chemistries. ToF-SIMS imaging was shown to be an ideal method of studying the distribution of specific ion species across the array and to confirm that the microarray was printed in the intended layout. Principal component analysis is shown to be an ideal technique to analyse both ToF-SIMS and XPS spectral data from the arrays, allowing similarities and differences in the surface chemistry of the polymers to be easily visualised. To estimate the surface energies of the arrayed polymers it is necessary to use picolitre volume droplets to make contact angle measurements. In Chapter 4 it is shown that contact angle measurements taken from picolitre volume water droplets are equivalent to those measured from more conventional microlitre droplets. In Chapter 5 picolitre contact angle measurements are used to estimate the polar and dispersive surface energies of a polymer microarray, which has been specifically designed to exhibit a maximum range of surface energy values. The analysis shows that there is indeed great variation in the WCA and polar surface energies of the polymers, demonstrating the power of intelligently designed combinatorial libraries. To understand the chemical basis of this large range of surface energies the results are compared to surface chemical data from ToF-SIMS and XPS. Surface atomic and functional data from XPS is unable to provide any definitive explanations for the range of surface energies observed. However, information about the molecular structure of the surface from ToF-SIMS gives an insight into what surface functionalities are responsible for high and low surface energies. In Chapter 6 PLS regression is investigated further as a method for investigating surface structure-property relationships in large polymer libraries. Specifically two issues are investigated: the influence of sample number on the results obtained and the ability of PLS to make quantitative predictions. The ToF-SIMS and surface energy dataset discussed in Chapter 5 is used for this task. It is demonstrated that the results obtained from PLS models of large polymer libraries are equivalent to those obtained from much smaller datasets, in terms of the ions identified in the regression vector. Using various test sets of polymers it is shown that there is a limit to the predictive ability of PLS: specifically, as the difference between the training and test sets increases, the quality of the predictions decreases. Potential problems with data pre-processing and re-scaling are also identified. In the final experimental chapter two methods are described for investigating protein adhesion and adsorption to micro-arrayed polymers using AFM and fluorescently labelled proteins. Both methods indicate a wide range of protein adsorption properties within the group of polymers analysed. A good correlation between the two sets of data was observed which appears to validate both methods. In summary the work described in this thesis has demonstrated the feasibility of the characterisation of the surface chemistry, energetics and protein adsorption properties of a micro-arrayed polymer library within realistic time-frames. PCA and PLS have been shown to be useful tools for analysing the data obtained. It is hoped that the methods described in this thesis will allow the biological data from polymer microarrays to be rationalised using the surface properties of the polymers, allowing the design of new biomaterials.
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Perkins, John Bigelow. "Surface ship overhaul decision analysis." Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/30591.
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Approved for public release; distribution is unlimited.<br>Efficient Surface Ship Maintenance and repair is vital to the U.S. Navy. With defense budgets tightening, accurate and economically sound decision making in this program is essential. To improve decision making, it would be helpful to have an accurate analysis program to evaluate the adequacy of ship maintenance and repair decisions. This system should use available overhaul information to identify errors made during the overhaul process. This thesis analyses current Navy ship maintenance and repair feedback processes to determine if any system is used presently that adequately measures the accuracy of decisions made within the Surface Ship Maintenance Program. Further, this thesis develops an overhaul decision analysis model to assess the present Navy surface ship decision process. Finally, this thesis draws conclusions based on application of the model. These findings address both cost and equipment readiness issues to demonstrate the benefits of an an effective surface ship decision analysis program.... Surface ship overhaul decision process, Surface ship overhaul feedback systems.
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Jackson, Stuart Thomas. "Surface analysis of polymer blends." Thesis, University of Sheffield, 1993. http://etheses.whiterose.ac.uk/14740/.
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Hughes, Gareth Martin. "Surface analysis of orthopaedic implants." Thesis, University of Bristol, 2003. http://hdl.handle.net/1983/03628cc5-0770-4017-97c4-7753d184e308.
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Staggemeier, Bethany Ann. "Dynamic surface tension detection : novel applications to continuous flow analysis and interfacial analysis /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/11584.
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Thompson, Alice B. "Surface-tension-driven coalescence." Thesis, University of Nottingham, 2012. http://eprints.nottingham.ac.uk/12522/.
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When fluid droplets coalesce, the flow is initially controlled by a balance between surface tension and viscosity. For low viscosity fluids such as water, the viscous lengthscale is quickly reached, yielding a new balance between surface tension and inertia. Numerical and asymptotic calculations have shown that there is no simply connected solution for the coalescence of inviscid fluid drops surrounded by a void, as large amplitude capillary waves cause the free surface to pinch off. We analyse in detail a linearised version of this free boundary problem. For zero density surrounding fluid, we find asymptotic solutions to the leading order linear problem for small and large contact point displacement. In both cases, this requires the solution of a mixed type boundary value problem via complex variable methods. For the large displacement solution, we match this to a WKB analysis for capillary waves away from the contact point. The composite solution shows that the interface position becomes self intersecting for sufficiently large contact point displacement. We identify a distinguished density ratio for which flows in the coalescing drops and surrounding fluid are equally important in determining the interface shape. We find a large displacement solution to the leading order two-fluid problem with a multiple-scales analysis, using a spectral method to solve the leading order periodic oscillator problem for capillary waves. This is matched to a single-parameter inner problem, which we solve numerically to obtain the correct boundary conditions for the secularity equations. We find that the composite solution for the two-fluid problem is simply connected for arbitrarily large contact-point displacement, and so zero density surrounding fluid is a singular limit.
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Fan, Yichao. "The analysis of surface defects using the ultrasonic Rayleigh surface wave." Thesis, University of Warwick, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.495017.
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Surface defects, such as rolling contact fatigue (RCF) cracking, can be a difficult class of surface defects for existing on-line non-destructive testing techniques to detect and size accurately at high speed. Gauge corner cracking on the running surface of the railway track is a type of RCF defect. There are economic and safety benefits to have an accurate, fast and reliable NDT technique to detect such defects. The EMAT pitch-catch ultrasonic testing technique, using the Rayleigh surface wave developed at the laser ultrasound group, has been shown to be able to detect and size surface defects. The pitch-catch geometry also allows this technique to be used at high speed, for on-line NDT applications.
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Martin, Nicholas Joseph. "Surface analysis for proteomics via liquid extraction surface analysis mass spectrometry and liquid chromatography mass spectrometry." Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/6493/.
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Liquid extraction surface analysis (LESA) is an ambient ionisation technique which allows direct analysis of surfaces coupled with mass spectrometry. LESA mass spectrometry has been used successfully to analyse small molecules, but there are a limited number of examples where the approach has been applied to protein analysis. The work presented here aims to develop novel applications of LESA mass spectrometry of proteins. LESA mass spectrometry was used to analyse intact proteins from polymeric membranes. The rationale for these experiments was the potential application to analyse proteins electroblotted following polyacrylamide gel electrophoresis, i.e. top-down proteomics, and in air monitoring. The subsequent focus was dried blood spot (DBS) analysis. An automated LESA based trypsin digestion protocol was developed and coupled with liquid chromatography tandem mass spectrometry to enable DBS proteomics. i.e., untargeted global protein identification via a bottom-up approach. Approaches for DBS proteomics (in the absence of LESA) were explored further using conventional digestion procedures coupled with protein depletion. LESA was also applied for targeted analysis of proteins from DBS, to determine variants of alpha-1-antitrypsin. Finally, native LESA mass spectrometry was developed to analyse non-covalent complexes from dried surfaces. Native LESA mass spectrometry successfully identified the haemoglobin tetramer directly from DBS.
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Zhang, Eugene. "Surface Topological Analysis for Image Synthesis." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5038.
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Topology-related issues are becoming increasingly important in Computer Graphics. This research examines the use of topological analysis for solving two important problems in 3D Graphics: surface parameterization, and vector field design on surfaces. Many applications, such as high-quality and interactive image synthesis, benefit from the solutions to these problems.
Surface parameterization refers to segmenting a 3D surface into a number of patches and unfolding them onto a plane. A surface parameterization allows surface properties to be sampled and stored in a texture map for high-quality and interactive display. One of the most important quality measurements for surface parameterization is stretch, which causes an uneven sampling rate across the surface and needs to be avoided whenever possible. In this thesis, I present an automatic parameterization technique that segments the surface according to the handles and large protrusions in the surface. This results in a small number of large patches that can be unfolded with relatively little stretch. To locate the handles and large protrusions, I make use of topological analysis of a distance-based function on the surface.
Vector field design refers to creating continuous vector fields on 3D surfaces with control over vector field topology, such as the number and location of the singularities. Many graphics applications make use of an input vector field. The singularities in the input vector field often cause visual artifacts for these applications, such as texture synthesis and non-photorealistic rendering. In this thesis, I describe a vector field design system for both planar domains and 3D mesh surfaces. The system provides topological editing operations that allow the user to control the number and location of the singularities in the vector field. For the system to work for 3D meshes surface, I present a novel piecewise interpolating scheme that produces a continuous vector field based on the vector values defined at the vertices of the mesh. I demonstrate the effectiveness of the system through several graphics applications: painterly rendering of still images, pencil-sketches of surfaces, and texture synthesis.
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Chiang, Joyce Hsien-yin. "Multivariate analysis of surface electromyography signals." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/31587.
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As the primary method of measuring muscle activation, the surface electromyography (sEMG) is of great importance in the study of motor deficits seen in patients with brain injuries and neuromuscular disorders. While clinicians have long intuitively understood that deficits in motor control are related to inappropriate recruitment of muscle synergies across several muscles, sEMG recordings are still typically examined in a univariate fashion. However, most traditional univariate techniques are unable to quantitatively capture the complex interactions between muscles during natural movements. To address this issue, multivariate signal processing techniques are employed in this thesis to study muscle co-activation patterns in patient populations. A method for classification of multivariate sEMG recordings between stroke and healthy subjects is proposed. The proposed classification scheme utilizes the eigenspectra of time-varying covariance patterns between sEMG channels as feature vectors and the support vector machines (SVM) as classifiers. Despite the minimal differences in the RMS profiles of individual muscles, the proposed scheme is able to effectively differentiate between healthy and stroke subjects. Moreover, the classification rate is shown to be monotonically related to the severity of motor impairment. This simple, biologically-inspired approach is able to quantitatively capture the subtle differences in muscle recruitment patterns between two populations and appears to be a promising means to measure motor performance. The other approach to modeling multivariate sEMG utilizes the HMM-mAR framework, which combines hidden Markov models (HMMs] and multivariate autoregressive (mAR) models. Different forms of sEMG data are analyzed, including raw sEMG, amplitude sEMG and carrier sEMG. The classification between healthy and stroke subjects is performed using structural features derived from estimated model parameters. Both the raw and carrier data produce excellent classification performance. The proposed method represents a fundamental departure from most existing classification methods where only amplitude sEMG is analyzed or mAR coefficients are directly used as feature vectors. In contrast, our analysis shows that the structural features of the carrier sEMG can enhance the classification performance and provide additional insights into motor control.<br>Applied Science, Faculty of<br>Electrical and Computer Engineering, Department of<br>Graduate
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Elghoul, zoelfikar, and Shobin John. "Surface Topographical Analysis Of Cutting Inserts." Thesis, Högskolan i Halmstad, Funktionella ytor, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-32217.
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The following report conducted with collaboration of the University of Halmstad and ABSandvik Coromant.The focus of the project is characterizing the surface topography of different surface treatmentvariants before and after chemical vapor deposition (CVD).As a part of improving the knowledge about the surface area characterization and accomplisha better knowledge and understanding about surfaces and its relation to wear of uncoatedWC/Co cutting tools The project initiated in February 2016 and end date was set to May2016.The methodology used in this thesis based on the statistical analysis of surface topographicalmeasurements obtained from interferometer and SEM by using Digital-Surf-MountainsMapsoftware.The finding from this thesis showed that Mean and Standard deviation method, Spearman’scorrelation analysis and Standard deviation error bar followed by ANOVA and T-test areeffective and useful when comparing between different variants.The thesis resulted in a measurement approach for characterizing different surfacetopographies using interferometer and SEM together with statistical analysis.Keywords: 3D-Surfaces Texture, CVD coating inserts, Interferometer, Spearman’s correlation andANOVA & T-test.
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Thom, Alasdair D. "Analysis of vortex-lifting surface interactions." Thesis, University of Glasgow, 2011. http://theses.gla.ac.uk/3037/.
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The interaction of a vortex with a lifting surface occurs in many aerodynamic systems, and can induce significant airloads and radiate impulsive noise. Yet due to their complex nature, the ability to accurately model the important flow physics and noise radiation characteristics of these interactions in realistic situations has remained elusive. This work examines two cases of vortex-lifting surface interactions by enhancing the capabilities of a high fidelity flow solver. This flow solver utilises high spatial discretisation accuracy with a 5th order accurate WENO scheme, and overset meshes to accurately resolve the formation, evolution and interaction of a tip vortex using an inviscid approximation of the fluid. An existing computational infrastructure is further developed and applied to analyse blade-vortex interactions that occur on a helicopter rotor. An idealised interaction is studied, where an independently generated vortex interacts with a rotor. It is found that through the employment of adequate spatial and temporal resolution, the current methodology is capable of resolving the important details of the interaction over a range of vortex-blade miss distances. A careful study of the spatial and temporal resolution requirements is conducted to ensure that the computed results converge to the correct physical solution. It is also demonstrated that a linear acoustic analysis can accurately predict the acoustic energy propagated from these interactions to the far-field, provided the blade surface pressures are accurately computed. The methodology is then used to study an idealised propeller wake-wing interaction, which occur behind a tractor mounted turboprop. A computationally efficient method of modelling the wake-wing interaction is developed and the computed surface pressures of the interaction are confirmed to agree well with the experimental data. The analysis is coupled to an optimisation algorithm to determine a novel wing design, and it is found that significant drag reductions can be achieved with small changes in the twist distribution of the wing. This work confirms that by using a combination of strategies including efficient grids, high order accurate numerical discretisations and a flexible software infrastructure, high fidelity methods can indeed be used to accurately resolve practical cases of vortex-lifting surface interactions in detail while being feasible in a design setting. The airloads and aeroacoustics from these interactions can be accurately predicted, thus confirming that with the modern advances in computing and algorithms, high fidelity methodologies such as those presented in this thesis are in a position to be used to gain a deep understanding of the relevant flow physics and noise radiation patterns, and their impact on aircraft design.
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McGurk, Simon L. "Surface analysis of novel biomedical polymers." Thesis, University of Nottingham, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267058.
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Clarke, Stuart. "Surface analysis of novel biomedical polymers." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342001.
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Li, Wenbin. "Nonrigid surface tracking, analysis and evaluation." Thesis, University of Bath, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.619212.
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Estimating the dense image motion or optical flow on a real-world nonrigid surface is a fundamental research issue in computer vision, and is applicable to a wide range of fields, including medical imaging, computer animation and robotics. However, nonrigid surface tracking is a difficult challenge because complex nonrigid deformation, accompanied by image blur and natural noise, may lead to severe intensity changes to pixels through an image sequence. This violates the basic intensity constancy assumption of most visual tracking methods. In this thesis, we show that local geometric constraints and long term feature matching techniques can improve local motion preservation, and reduce error accumulation in optical flow estimation. We also demonstrate that combining RGB data with additional information from other sensing channels, can improve tracking performance in blurry scenes as well as allow us to create nonrigid ground truth from real world scenes. First, we introduce a local motion constraint based on a laplacian mesh representation of nonrigid surfaces. This additional constraint term encourages local smoothness whilst simultaneously preserving nonrigid deformation. The results show that our method outperforms most global constraint based models on several popular benchmarks. Second, we observe that the inter-frame blur in general video sequences is near linear, and can be roughly represented by 3D camera motion. To recover dense correspondences from a blurred scene, we therefore design a mechanical device to track camera motion and formulate this as a directional constraint into the optical flow framework. This improves optical flow in blurred scenes. Third, inspired by recent developments in long term feature matching, we introduce an optimisation framework for dense long term tracking -- applicable to any existing optical flow method -- using anchor patches. Finally, we observe that traditional nonrigid surface analysis suffers from a lack of suitable ground truth datasets given real-world noise and long image sequences. To address this, we construct a new ground truth by simultaneously capturing both normal RGB and near-infrared images. The latter spectrum contains dense markers, visible only in the infrared, and represents ground truth positions. Our benchmark contains many real-world scenes and properties absent in existing ground truth datasets.
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Larkin, Bethany Alexandria Jane. "Bloodstain pattern analysis : scratching the surface." Thesis, Manchester Metropolitan University, 2015. http://e-space.mmu.ac.uk/579548/.
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Bloodstain Pattern Analysis (BPA) is a forensic application of the interpretation of distinct patterns which blood exhibits during a bloodletting incident, providing key evidence with its ability to potentially map the sequence of events. The nature of BPA has given the illusion that its evidentiary significance is less than that of fingerprints or DNA, relying solely on the interpretation of the analyst and focusing very little on any scientific evaluation. Recent preliminary literature studies have involved a more quantitative approach, developing directly crime scene applicable equations and methodology, which have established new ways of predicting the angle of impact, impact velocity, point of origin of blood and blood pattern type. Using these new equations and further improving on them to include a variation of impact surfaces, surface properties (i.e. porosity, roughness, manufacturing process etc.) and changes in blood properties is the principal focus of this work. The primary objective of this research is to expand the knowledge of blood and surface interactions and generate general equation/s or quantitative approaches that encompasses some of the possible conditions, in relation to Bloodstain Pattern Analysis (BPA), which may be encountered at a crime scene. Overall validating BPA and supporting a more reputable / respected scientific field giving credence to its usage within criminal trials. This thesis is presented in three parts: The first part explores blood, its characteristics and how manipulating the components of blood (i.e. packed cell volume, PCV), can alter the way a bloodstain forms and dries. Since packed cell volume is instrumental in the overall viscosity of blood, which ultimately determines the final bloodstain diameter via the natural fluctuation exhibited throughout the body and by the individual human characteristics, it was deemed necessary to investigate its effect on the interpretation of bloodstains. Packed cell volume was found to alter the size of bloodstains significantly, where increments in their diameter were experienced when PCV% was decreased; angled impacts were unaffected. The mechanism of drying blood was also analysed, the current understanding being that blood dries primarily by the Marangoni Effect. However this is found to be altered when PCV% is considered; low PCV% exhibits a strong Coffee Ring Effect where higher PCV% levels dry by the Marangoni Effect. Other drying characteristics considered were volume analysis, skeletonisation and the halo effect where PCV% was manipulated. Volume analysis methods were significantly affected by PCV%, where new drying constants were established and several established scientific methods were shown to be unreliable at determining the volume. The second part of this thesis investigates surface interaction, exploring the fundamentals of various common surface types, and how individual features (i.e. surface roughness) affect the interpretation of bloodstains; four common surfaces were considered (wood, metal, stone/tile and fabric). Blood drop tests were performed at different heights and angles where recently formulated equations were applied to the results to create new constants, which could be used to distinguish between surface types. Wood and fabric were found to alter the spread of blood most significantly, constants increased or decreased substantially, compared to the original value. The last part of this thesis expands the groundwork set forth in part two. Surfaces were manipulated, either by heat or cleaning. Since it is possible that blood may interact with a surface which may have been cleaned (to remove blood, or simply to clean surface prior to any blood impaction) or heated (i.e. radiators), it is important to fully explore surface alterations which commonly occur in an everyday environment and therefore are highly probable to be encountered at a crime scene. Surface manipulation is investigated in the form of a heated surface, where a blood boiling curve reminiscent of the water boiling curve was created establishing four visibly recognizable boiling regimes. Heat was found to decrease the resultant bloodstain diameter, separate blood into its components and create reduction rings as the temperature increased. An equation accounting for these changes was deduced, further showing how simple alterations to the surface, which have previously been overlooked, can interfere with the results. Further surface manipulation was implemented in the form of cleaning, since cleaning can be performed before blood impacts, therefore causing a surfactant layer, of after blood has impacted the surface, indicating crime evasion. Secondary analysis of blood on a heated surface in conjunction with cleaning was implemented, establishing the effectiveness of presumptive testing and the ability to extract valuable DNA. Initial presumptive testing and DNA extraction was found to be successful for all temperatures, however when various cleaning methods were applied (a common occurrence at crime scenes) DNA testing produced negative results at temperatures of 50oC onwards. Fabric washing, using various household detergents and methods of washing/drying were also evaluated. Detergents significantly increased the resultant diameters of bloodstains, secondary rings were experienced on all polyester and silk fabrics, establishing constants relating to the secondary ring produced. Repeated cycles of washing were found to produce a stable fabric after 6 cycles, for most fabric types.
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Razib, Muhammad. "Structural Surface Mapping for Shape Analysis." FIU Digital Commons, 2017. https://digitalcommons.fiu.edu/etd/3517.
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Natural surfaces are usually associated with feature graphs, such as the cortical surface with anatomical atlas structure. Such a feature graph subdivides the whole surface into meaningful sub-regions. Existing brain mapping and registration methods did not integrate anatomical atlas structures. As a result, with existing brain mappings, it is difficult to visualize and compare the atlas structures. And also existing brain registration methods can not guarantee the best possible alignment of the cortical regions which can help computing more accurate shape similarity metrics for neurodegenerative disease analysis, e.g., Alzheimer’s disease (AD) classification. Also, not much attention has been paid to tackle surface parameterization and registration with graph constraints in a rigorous way which have many applications in graphics, e.g., surface and image morphing.
This dissertation explores structural mappings for shape analysis of surfaces using the feature graphs as constraints. (1) First, we propose structural brain mapping which maps the brain cortical surface onto a planar convex domain using Tutte embedding of a novel atlas graph and harmonic map with atlas graph constraints to facilitate visualization and comparison between the atlas structures. (2) Next, we propose a novel brain registration technique based on an intrinsic atlas-constrained harmonic map which provides the best possible alignment of the cortical regions. (3) After that, the proposed brain registration technique has been applied to compute shape similarity metrics for AD classification. (4) Finally, we propose techniques to compute intrinsic graph-constrained parameterization and registration for general genus-0 surfaces which have been used in surface and image morphing applications.
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Guan, Yanlin. "Interactive and immersive surface interrogation techniques over triangulated surfaces." Diss., Mississippi State : Mississippi State University, 2003. http://library.msstate.edu/etd/show.asp?etd=etd-04142003-173417.
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Leppälä, Daniel. "Analysis of surface coverage in regards to surface functionalization : A microscopic approach." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-140994.
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The understanding of how white blood cells react when coming into contact with various surfaces is of major importance for a wide range of biomaterials and biosensor applications. In this study it is investigated if it is possible to determine how neutrophils react to a certain type of sensor chip called cell clinic being developed. This study investigates the cell surface coverage on the sensor chip and how it correlates to the signal response of the sensor at hand. Neutrophils, as other white blood cells, are cells that quickly adhere to surfaces and during the adhesion process they activate at different levels depending on i.e. type of surface or surface functionalization, this activation can be visualized by the change in morphology. While measuring the change of capacitance with the cell clinic sensor during cell adhesion, the cell surface coverage is of main importance. The main focus of this diploma work has been to develop an image analysis script capable of conducting automated analysis on a large body of images estimating the surface coverage. Input data for this modeling is taken from fluorescent microscopy images. The experiments conducted during this project have indicated that white blood cells adhered to the sensor surface shows signs of being activated also without external activation. This clearly shows that knowledge of how neutrophils react to surface modifications is of great importance as well as the awareness that any surface may trigger a response from the immune system i.e. neutrophil activation, so also in the cell clinic. It is a fact that it might be difficult to evaluate the effect of a foreign substance on the neutrophils while a significant amount is activated from being in contact with the surface. Regarding different surfaces the white blood cells does not display any preference of adhering to any specific surface. The surfaces used in this project was silicon oxide wafers, silicon oxide wafers with a nitride surface functionalization and the intended sensor chip; however the addition of PMA clearly shows an effect on how many cells that adheres to the surface as well as the average area of each cell.
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Moncayo, Marco Antonio. "Laser Modified Alumina: a Computational and Experimental Analysis." Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc177232/.
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Laser surface modification involves rapid melting and solidification is an elegant technique used for locally tailoring the surface morphology of alumina in order to enhance its abrasive characteristics. COMSOL Multiphysics® based heat transfer modeling and experimental approaches were designed and used in this study for single and multiple laser tracks to achieve densely-packed multi-facet grains via temperature history, cooling rate, solidification, scanning electron micrographs, and wear rate. Multi-facet grains were produced at the center of laser track with primary dendrites extending toward the edge of single laser track. The multiple laser tracks study indicates the grain/dendrite size increases as the laser energy density increases resulting in multiplying the abrasive edges which in turn enhance the abrasive qualities.
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Lau, Chi Hian. "Chemical, electronic and electrochemical properties of diamond thin films." Thesis, University of Oxford, 2002. http://ora.ox.ac.uk/objects/uuid:53a0886c-14ad-431a-975d-0ecca8fc8968.
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Diamond is of interest as an advanced functional material, since the extreme physical properties of diamond, suggests it is ideally suited to a range of new demanding applications. In this context, the thesis explores basic surface chemical properties of diamond thin films, along with electrochemical, electronic and electron emission processes involving this material. New experiments are reported concerning the nature of surface conductivity on diamond. Measurements clearly show that the conductivity only arises if a hydrogenated diamond surface is exposed to water vapour, in the presence of chemical species capable of acting as electron acceptors. The conduction properties of surface conductive diamond in aqueous solution are also studied, and the first detailed electrochemical investigations of this material are described. Comparative electrochemical studies of nanocrystalline and boron-doped diamond have been performed. Investigations of electrode stability, and the accessible "potential window" are described, as well as the behaviour of a range of 'redox' systems, including transition metal complexes, metal deposition/stripping, and bio-related organic species. Significant differences between the behaviour of nanodiamond and microcrystalline boron-doped material are observed. A range of surface chemical and threshold photoemission studies of diamond thin films are reported. The results indicate that quantum photoyields (QPYs) are insensitive to the diamond "quality", although the wavelength selectivity is dependent on it. The adsorption of oxygen strongly reduces the QPY, although this only occurs slowly in the presence of O<sub>2</sub> because of a low reactive sticking probability. Much more rapid uptake of oxygen and consequent reduction of photoyield is observed in the presence of atomic O or electronically excited dioxygen O<sub>2</sub>*. The presence of alkali metals on the diamond surface increases the QPY, and reduces the sensitivity of the QPY to surface oxygen. Significant differences between the surface chemical properties of Li, and other adsorbed akali metals (K and Cs) are observed.
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Bigelow, Alan W. "Energy Distribution of Sputtered Neutral Atoms from a Multilayer Target." Thesis, University of North Texas, 2000. https://digital.library.unt.edu/ark:/67531/metadc2657/.
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Energy distribution measurements of sputtered neutral particles contribute to the general knowledge of sputtering, a common technique for surface analysis. In this work emphasis was placed on the measurement of energy distribution of sputtered neutral atoms from different depths. The liquid Ga-In eutectic alloy as a sample target for this study was ideal due to an extreme concentration ratio gradient between the top two monolayers. In pursuing this study, the method of sputter-initiated resonance ionization spectroscopy (SIRIS) was utilized. SIRIS employs a pulsed ion beam to initiate sputtering and tunable dye lasers for resonance ionization. Observation of the energy distribution was achieved with a position-sensitive detector. The principle behind the detector's energy resolution is time of flight (TOF) spectroscopy. For this specific detector, programmed time intervals between the sputtering pulse at the target and the ionizing laser pulse provided information leading to the energy distribution of the secondary neutral particles. This experiment contributes data for energy distributions of sputtered neutral particles to the experimental database, required by theoretical models and computer simulations for the sputtering phenomenon.
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Hofert, Glenn D. "Spectral analysis of vortex/free-surface interaction." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1994. http://handle.dtic.mil/100.2/ADA283210.
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Bora, Ethem. "Cylindrical Surface Analysis with White Light Interferometry." Thesis, Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-15308.
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At present, one of the big challenges is to develop a precise surface measurement method for mechanical parts. Especially, to study cylindrical surface, the cause of many difficulties because of its geometry shape. This thesis presents a quite good solution for analyzing topography of cylindrical surface with White Light Interferometry optical system which is one of the important and suitable tools in optics. In the construction period, the aim was to build a system which can be easily mounted on the sample. This is done by a very simple and compact design that also enables us to use it in research laboratories. In the project, a cylindrical surface analysis is achieved by taking subsequent images with different nano-scale distance from the sample and stitched the acquired images. To achieve this implementation, subsequent images with the highest intensity are first determined and then located in a single image. In the stitching process, cross correlation method that is extremely useful to find out relative point of the images is used to merge the acquired images. Additionally, stitching process is helped us to extend the area where research can be done. In the project, MATLAB & LABVIEW are used for analyzing the images and controlling the motors, respectively.
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Hui, Ip Kee. "Analysis of surface mount technology solder joints." Thesis, Brunel University, 1996. http://bura.brunel.ac.uk/handle/2438/5380.
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The factors determining the quality of surface mount technology (SMT) solder joints are numerous, and complex. The exploration of these factors, and how they may affect the reliability and quality of the joints can only be achieved through continuous research. In this project, essential areas of SMT joints were selected for study and analysis, with the intention of providing additional design and process guidelines for the production of quality SMT joints. In the infrared reflow process, one of the common defect phenomena is the occurrence of tombstoning; that is after soldering only one end of the component is soldered while the other is lifted up, assuming a position like a tombstone. The initiation of tombstoning during reflow was analysed based on the forces acting on the component. A model was developed to predict the initiation of this phenomenon. The model shows that, under vibration-free conditions, the surface tension of the molten solder is the source of the force causing the initiation of tombstoning. The contact angle, which varies with the length of the printed circuit board solder land, has a significant effect on the value of the surface tension acting as a force pulling upward on the component. The model further shows that tombstoning initiation is due to the combined effects of the surface tension; the weight of the component; the dimensions of the component; the length of the solder underneath the component; and the length of the solder protruding from the end of the component. Selected components were used as examples for predicting the conditions of initiation, and these conditions were further substantiated by a series of experiments. Another area of study was a method which directly pulled the components off printed circuit boards and this was used as a means for testing the bond quality of surface mount technology leadless chip solder joints. Components D7243, CC1206, RC1206, RC121O, and CC1 812 were selected for this study. It was found that the ultimate tensile force which breaks a component off the printed circuit board has the potential to be used as a parameter for measuring the quality of the solder joint. The effect of solder thickness on the strength of a joint has also been investigated. The shape of joints soldered by two methods, wave soldering and infrared reflow, were compared. Joints at the two ends of a component produced by infrared reflow were found more uniform than the ones produced by wave soldering. A recommendation is made here for the wave soldering approach in achieving uniform solder joints. The effects of solder shape on the joint strength were further investigated by finite element analysis. A convex joint was found marginally more robust than a concave joint. Two aspects of the internal structure of SMT solder joints were investigated, void content and copper/tin intermetallic compounds. The voiding conditions of wave-soldered and infrared reflow joints were compared. No voids were found in all specimens that were produced by wave soldering. However, there were always voids inside joints produced by infrared reflow. Microhardness tests indicated that the hardness of compounds at the copper/solder interface of infrared reflowed joints is lower than that in the wave-soldered joints. It is considered that the lower hardness of the interfacial region of the infrared reflowed joints is due to the presence of voids. Scanning electron microscopy was used to study the formation of copper/tin intermetallic compounds for joints produced by infrared reflow. The results show that Cu 6 Sn5 was the only compound with a detectable thickness. Other compounds such as Cu3 Sn, were virtually not found at all. Aging of the joints at 100°C, shows that both the Cu 6Sn5 and the overall interfacial thickness grew with time. One of the important areas which had been overlooked previously and was studied in some details was the effects of solder paste exposure on the quality of solder paste. The characteristic changes of solder paste due to exposure were investigated in three areas, weight loss, tackiness, and rheology. The evaporation of low boiling point solvents was considered as the main contribution to the loss in the weight of the solder paste. The weight loss against exposure time was found to follow an exponential behaviour. A method was designed to evaluate the tackiness changes of solder paste due to exposure. It was found that the decay of tackiness against exposure time can be expressed by a power law. It is recommended that solder paste manufacturers should provide the necessary characteristic constants so as to enable the characteristics to be calculated after a specific exposure. The rheological changes of the solder paste as a result of exposure were also investigated. The implication on the printability of the solder paste due to these changes was studied and discussed.
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Dowsett, David Mark Francis. "High Brightness Ion Sources for Surface Analysis." Thesis, University of Warwick, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491929.
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The aim of this work was to produce an ion source with a high brightness and low energy spread. Two approaches were taken, an existing high brightness ion source (the liquid metal ion source) was monochromated to reduce its energy spread; this work was carried out at the University of York. The second approach was to develop a novel high brightness ion source with an intrinsically low energy spread. This approach was carried out at the University of Warwick. Several potential monochromators were simulated and the concentric hemispherical analyser was found to be the most suitable. Liquid metal ion sources were fabricated for monochromation by the author. However, these sources did not prove to be sufficiently stable for energy spread measurements and electron sources were used to try to demonstrate the principal. Ultimately this approach did not prove successful and the alternative ofdeveloping a novel source was pursued. This second approach utilises a novel emission process discovered at Warwick: surface enhanced field emission. Alkali metal vapours incident on a hot, chemically etched molybdenum wire are ionised at fields much lower than those normally required for field emission. Emission currents of several microamps have been obtained from the source and the sample current found to extremely stable with r.m.s noise of just 0.65%. The axial angular intensity of the source is 23 ~A sfl at 1 ~A emission. SIMS depth profiling has been carried out and the dynamic range at 1 keY was 3 orders of magnitude. Spot sizes of 20 ~m have been measured at 1 keY. The dynamic range and spot size do not represent the ultimate performance of the source, both are expected to improve in an ion column designed for a high brightness source.
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Harp, Keith. "An empirical analysis of visible surface algorithms." Thesis, Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/8537.
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Inchley, A. J. "Surface analysis of solutions using photoelectron spectroscopy." Thesis, University of East Anglia, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233547.
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Khan, M. A. "Modified poly(styrene) : Surface analysis and biointeractions." Thesis, University of Nottingham, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233675.
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Farooq, Abdul Rehman. "Dynamic photometric stereo for complex surface analysis." Thesis, University of the West of England, Bristol, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409451.
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Ton-That, Cuong. "Surface analysis of modified and blended polymers." Thesis, Robert Gordon University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325401.
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Craib, Glenn R. G. "Thin film structural determination and surface analysis." Thesis, University of Aberdeen, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320771.
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A combined approach to the use of surface analysis techniques and X-ray diffraction has been introduced. In particular the development of the microstructure of UHV evaporated thin metallic films has been investigated with a view to clarifying influences on microstructure (particularly texture). This study has shown the wide range of experimental parameters which affect the final film structure, such as temperature, oblique incidence and substrate roughness. An automated energy dispersive X-ray diffractometer has been developed for the study of thin film texture. The required corrections for loss of intensity due to sample positioning have been developed and verified. Pole figures have been collected for erbium and nickel thin films (thickness 200-1200 nm) grown on molybdenum or glass substrates. Results for the erbium films show a substantial effect on the texture of the film, contributed by the temperature of the substrate during deposition. The texture varies from mixed fiber at low temperature, to a strong single fiber orientation at around 663 K, to mixed fiber at higher temperatures. The strong orientation at 663 K has been shown to vary from either (002) to (101) depending on as yet unknown experimental conditions. The effect of substrate roughness appears to be only in the degree of orientation and it does not affect the overall nature of the texture of the film. The texture of the nickel films shows a form of "granular epitaxy" at substrate temperatures above 300 K. The presence of tensile stress within one of these nickel thin film samples has been determined and is interpreted to give support to a proposed mode of granular epitaxy.
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Atkinson, Gary A. "Surface shape and reflectance analysis using polarisation." Thesis, University of York, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.437614.
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Khadilkar, Harshad (Harshad Dilip). "Analysis and modeling of airport surface operations." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/67187.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2011.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 97-99).<br>The focus of research in air traffic control has traditionally been on the airborne flight phase. Recently, increasing the efficiency of surface operations has been recognized to have significant potential benefits in terms of fuel and emissions savings. To identify opportunities for improvement and to quantify the consequent gains in efficiency, it is necessary to characterize current operational practices. This thesis describes a framework for analysis of airport surface operations and proposes metrics to quantify operational performance. These metrics are then evaluated for Boston Logan International Airport using actual surface surveillance data. A probabilistic model for real-time prediction of aircraft taxi-out times is described, which improves upon the accuracy of previous models based on queuing theory and regression. Finally, a regression model for estimation of aircraft taxi-out fuel burn is described. Together, the modules described here form the basis for a surface operations optimization tool that is currently under development.<br>by Harshad Khadilkar.<br>S.M.
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Al-Tahir, Raid A. "Interpolation and analysis in hierarchical surface reconstruction /." The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487862972135505.
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Edussuriya, Suchitra Samanthi. "Computational analysis of viscoelastic free surface flows." Thesis, University of Greenwich, 2003. http://gala.gre.ac.uk/6159/.
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The demand for increasingly small and lightweight products require micro-scale components made of materials which are durable and light. Polymers have therefore become a popular choice since they can be used to produce materials which meet industrial requirements. Many of these polymers are viscoelastic fluids. The reduction in the sizes of components make physical experimentation difficult and costly. Therefore computational tools are being sought to replace old methods of testing. This research has been concerned with the development of a finite volume algorithm for viscoelastic flow which can be readily applied to real world applications. A major part of the research involved the implementation of the Oldroyd-B constitutive equations and associated solution methods, in the 3-D multi-physics software environment PHYSICA+. This provides an unstructured finite volume solution technique for viscoelastic flow. This algorithm is validated using the 4:1 planar contraction and results are reported. The developed viscoelastic algorithm has also been coupled with two interface tracking techniques one of which includes surface tension effects. These techniques are the Scalar Equation Algorithm (SEA) and the Level Set Method (LSM). With both techniques the algorithms are able to take into account flow effects from both fluids (ie. air and polymer) in a two-fluid system. The LSM technique maintains a sharp interface overcoming the smearing of the interface which generally affects interface tracking techniques on Eulerian fixed grids, for example SEA, and enables the curvature of the interface to be calculated accurately to implement surface tension effects. This integrated viscoelastic flow solver and free surface algorithm is then illustrated by predicting two industrial flow processes as used in the electronic packaging industry.
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BERGAMO, PAOLO. "Surface Wave Analysis in Laterally Varying Media." Doctoral thesis, Politecnico di Torino, 2012. http://hdl.handle.net/11583/2502664.
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This work studies the possibility of using surface wave analysis as a tool for a robust estimation of the S-wave velocity behaviour in laterally varying media. The surface wave method, in fact, can be effectively adopted for different purposes and at different scales, but I focused on the geo-engineering and geotechnical applications of surface wave analysis and also on the production of near-surface models for deep exploration: in both cases the aim is to retrieve the trend of the S-wave velocity in the first tens up to hundreds meters of depth of the subsoil. The surface wave method exploits the geometric dispersion proper of surface waves: in a non-homogeneous medium every frequency is characterized by a different phase velocity, as every frequency component travels through a portion of medium whose thickness is proportional to its wavelength. The curve associating every frequency component to its phase velocity is called dispersion curve, and it constitutes the experimental datum one uses for the solution of an inverse problem to estimate the behaviour of S-wave velocity in the subsurface. The inversion is performed by assuming a 1D forward modelling simulation and suffers from equivalence problems, leading to the non uniqueness of the solution. Despite its great ductility, the main limitation of surface wave method is constituted by its 1D approach, which has proved to be unsatisfactory or even misleading in case of presence of lateral variations in the subsoil. The aim of the present work is to provide data processing tools able to mitigate such limitation, so that the surface wave method can be effectively applied in laterally varying media.
As far as the inadequacy of surface wave method in case of 2D structures in the subsoil, I developed two separate strategies to handle smooth and gradual lateral variations and abrupt subsurface heterogeneities. In case of smooth variations, the approach I adopted aims at “following” the gradual changes in subsoil materials properties. I therefore propose a procedure to extract a set of neighbouring dispersion curves from a single multichannel seismic record by applying a suitable spatial windowing of the traces. Each curve corresponds to a different subsoil portion, so that gradual changes in subsoil seismic parameters can be reconstructed through the inversion of dispersion curves. The method was tested on synthetic and real datasets, but proved its reliability in processing the data from a small scale seismic experiment as well. In the context of characterizing smooth 2D structures in the subsurface via the surface wave method, I also developed a procedure to quantitatively estimate the (gradual) lateral variability of model parameters by comparing the shape of local dispersion curves, without the need to solve a formal inverse problem. The method is based on a sensitivity analysis and on the applications of the scale properties of surface wave. The procedure can be devoted to different applications: I exploited it to extend a priori local information to subsoil portions for which an experimental dispersion curve is available and for an estimation of the lateral variability of model parameters for a set of neighboring dispersion curves. The method was successfully applied to synthetic and real datasets.
To characterize sudden and abrupt lateral variations in the subsurface, I adopted another strategy: the aim is to estimate the location and embedment depth of sharp heterogeneities, to process separately the seismic traces belonging to quasi-1D subsoil portions. I adapted several methods, already available in literature but developed for different purposes and scales, to the detection of sudden changes in subsoil seismic properties via the analysis of anomalies in surface wave propagation. I got the most promising results when adapting these methods, originally developed for single shot configurations, to multifold seismic lines, exploiting their data redundancy to enhance the robustness of the analyses.
The outcome of the thesis is therefore a series of processing tools that improve the reliability and the robustness of surface wave method when applied to the near surface characterization of laterally varying media.
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陳彤{272b21} and Tong Chen. "Numerical computations on free-surface flow." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B31238245.
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Chen, Tong. "Numerical computations on free-surface flow /." Hong Kong : University of Hong Kong, 1999. http://sunzi.lib.hku.hk/hkuto/record.jsp?B21020292.
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Yeh, Yun-Peng. "Surface engineering for biological recognition." Thesis, Cranfield University, 2010. http://dspace.lib.cranfield.ac.uk/handle/1826/4585.
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The underlying idea of this thesis is that the surface chemical and morphological nature of bacterial strains uniquely differentiates one from another and hence can be used as the basis for their identification and control. It follows that their interactions with an artificial substratum uniquely characterize them. In principle, potentially it is easier and faster to evaluate the interfacial energy between a bacterium and a substratum than to characterize its genome or determine molecular biomarkers characteristic of the strain, hence validation of this thesis opens the way to rapid screening and diagnosis. Auxiliary to this main idea, an advanced metrology for evaluating the interfacial energies has been developed, exploiting the power of kinetic analysis.
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McKibben, John Ferney. "A Computational fluid dynamics model for transient three-dimensional free surface flows." Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/5790.
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Hata, Misako. "Non linear tolerance analysis by response surface methodology." Ohio : Ohio University, 2001. http://www.ohiolink.edu/etd/view.cgi?ohiou1173897314.
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Harvey, Alan Paul. "Nonlinear surface acoustic waves and applications." Thesis, University of Southampton, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.255827.
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Ge, Zhongfu. "Analysis of surface pressure and velocity fluctuations in the flow over surface-mounted prisms." Diss., Virginia Tech, 2004. http://hdl.handle.net/10919/25965.
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The full-scale value of the Reynolds number associated with wind loads on structures is of the order of 10^7. This is further complicated by the high levels of turbulence fluctuations associated with strong winds. On the other hand, numerical and wind tunnel simulations are usually carried out at smaller values of Re. Consequently, the validation of these simulations
should only be based on physical phenomena derived with tools capable of their identification. In this work, two physical aspects related to extreme wind loads on low-rise structures are examined. The first includes the statistical properties and prediction of pressure peaks. The second involves the identification of linear and nonlinear relations between pressure peaks and associated velocity fluctuations.
The first part of this thesis is concerned with the statistical properties of surface pressure time series and their variations under different incident flow conditions. Various statistical tools, including space-time correlation, conditional sampling, the probability plot and the probability plot correlation coefficient, are used to characterize pressure peaks measured on the top surface of a surface-mounted prism. The results show that the Gamma distribution provides generally the best statistical description for the pressure time series, and that the method of moments is sufficient for determining its parameters. Additionally, the shape parameter of the Gamma distribution can be directly related to the incident flow conditions. As for prediction of pressure peaks, the results show that the probability of non-exceedence can best be derived from the Gumbel distribution. Two approaches for peak prediction, based on analysis of the parent pressure time series and of observed peaks, are presented. The prediction based on the parent time series yields more conservative estimates of the probability of non-exceedence.
The second part of this thesis is concerned with determining the linear and nonlinear relations between pressure peaks and the velocity field. Validated by analytical test signals, the wavelet-based analysis is proven to be effective and accurate in detecting intermittent linear and nonlinear relations between the pressure and velocity fluctuations. In particular, intermittent linear and nonlinear velocity pressure relations are observed over the nondimensional frequency range fH/U<0.32. These results provide the basis for flow parameters and characteristics required in the simulation of the wind loads on structures.<br>Ph. D.
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Waterworth, Adelle. "Quantitative characterisation of surface finishes on stainless steel sheet using 3D surface topography analysis." Thesis, University of Huddersfield, 2006. http://eprints.hud.ac.uk/id/eprint/385/.
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The main aim of this project was to quantitatively characterise the developed surface topography of finishes on stainless steel sheet using three-dimensional surface analysis techniques. At present surface topography is measured using (mainly) stylus profilometry and analysed with 2D parameters, such as Ra, Rq and Rz. These 2D measurements are not only unreliable due to a lack of standardised measurement methodology, but are also difficult to relate directly to the actual shape of the topography in 3 dimensions. They bear little direct relation to the functional properties of the surface of stainless steel, making them less useful than their 3D counterparts. Initially it is crucial to ensure that the surface topography data collected is correct, accurate and relevant, by defining a measurement strategy. Models of the surface topography are developed encompassing the usual features of the topography and variations in the topography caused by production or 'defects'. The functional features are discussed and predicted relevant parameters are presented. The protocol covers the selection of the correct measuring instrument based on the surface model and the size of the relevant functional features so that the desired lateral and vertical resolution and range is achievable. Measurement data is then analysed using Fast Fourier Transforms (FFTs) to separate the different frequencies within the spatial frequencies detected on the surface. The frequency of the important features shows up dominantly on a Power Spectral Density (PSD) plot and this is used to find the correct sampling interval to accurately reconstruct the 3D surface data. The correct instrument for further measurements is then selected using a Steadman diagram. Operational details of the measuring instruments available for this project are given and variables for these instruments are discussed. Finally, measurement method recommendations are made for each of the four finishes modelled. Based on this surface characterisation an attempt is made to identify the 3D parameters that give a quantitative description of common stainless steel sheet finishes with respect to some aspects of their production and functional performance. An investigation of the differences in manufacturing processes, gauge and grade of material is presented, providing an insight into the effect on topography of such divergences. The standardised 3D parameter set is examined to determine its sensitivity to common variations in the topography of the 2B finish and therefore their potential relevance. A new data separation technique of the material probability curve for use on the 3D datasets establishes a cut-off (transition point) between the two main functionally relevant features of the 2B surface (plateaus and valleys) by finding the intersection of the asymptotes of a fitted conic section, giving a non subjective methodology to establish the section height. The standardised 3D parameters are then used on the separated data, with the aim of being more functionally relevant to the main surface studied. Functional tests to rate capability of these parameters in the areas of optical appearance, lubricant retention and corrosion are carried out and the appropriate topography parameters are related to their performance.