Dissertations / Theses on the topic 'Surface technique'
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Clayton, Peter Edward. "Automating the Moire Interferometry technique." Thesis, University of Nottingham, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260657.
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Brunon, Céline. "Application des caractérisations de surface par XPS, ToF-SIMS, SIMS, EELS, SEM, AFM et TEM à la compréhension des mécanismes de protection antimicrobienne de textiles modifiés par traitements de surface." Thesis, Lyon 1, 2010. http://www.theses.fr/2010LYO10294.
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Ce travail de thèse s’inscrit dans la partie caractérisation d’un projet collaboratif ayant pour objectif d’élaborer des textiles antimicrobiens pour différents domaines d’application, en particulier les domaines de la santé et de l’agroalimentaire. La démarche analytique a consisté à combiner différentes techniques d’analyse de surface (techniques microscopiques (SEM, AFM, TEM) et spectroscopiques (XPS, ToF-SIMS, SIMS, EELS)) avec des analyses microbiologiques pour aider à la compréhension des mécanismes de protection antimicrobienne des textiles traités. Les agents antimicrobiens, l’argent et le Poly HexaMéthylène Biguanide (PHMB), ont été déposés respectivement par plasma (PVD / PECVD) et par foulardage. Les contraintes liées aux domaines d’application des textiles étudiés (implants herniaires et vêtements professionnels) ont été prises en compte (respectivement, quantité minimale de l’agent antimicrobien et résistance au lavage industriel). Malgré certaines contaminations inhérentes à des procédés industriels, les analyses de surface se sont révélées être un ensemble d’outils essentiel au développement des procédés (qualité du dépôt, influence des conditions de dépôt, influence du lavage). Selon les domaines d’application, l’analyse à très haute sensibilité en extrême surface et l’étude de la distribution en profondeur de l’agent antimicrobien ont été des étapes clés pour la compréhension des propriétés antimicrobiennes observées pour les dépôts, démontrant la pertinence de l’approche multi-analytique choisie dans ce travail de thèseThis thesis work concerns the characterization effort within a cooperation project aiming at developing antimicrobial textiles for various application fields, particularly health applications and food-processing industry. The analytical approach combined different surface analysis techniques (microscopy techniques (SEM, AFM, TEM) and spectroscopy techniques (XPS, ToF-SIMS, SIMS, EELS)) to microbiological tests in order to understand the antimicrobial activity of deposits at the surface of textiles. Silver and Poly Hexamethylene Biguanide (PHMB) antimicrobial agents were deposited by plasma (PVD / PECVD) and padding, respectively. Specific constraints related to the application fields (hernia implants and clothing) were considered (minimum concentration in antimicrobial agent and resistance to industrial washing, respectively). Despite some ubiquitous contamination related to industrial processes, surface analysis techniques proved to be an essential help to develop these processes (deposit quality, influence of deposition conditions, influence of washing). Depending on the application fields, high sensitivity surface analysis at the extreme surface and in-depth distribution of the antimicrobial agent were essential to understand the antimicrobial properties of the deposits, which confirms the relevance of the multi-analytical approach used in this thesis work
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Ghosh, Sourav Kumar. "Anharmonic acoustic technique for detection of surface-bound particles." Thesis, University of Cambridge, 2011. https://www.repository.cam.ac.uk/handle/1810/243858.
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Receptor-based biological detection techniques often suffer from the problem of non-specific interactions. This is largely due to the presence of weak electrostatic and Van der Waals forces between the receptor and the non-target substances in the analyte that are not easily dissociated in practice. Most existing detection techniques are unable to probe the interaction between the bound entity and the surface and differentiate between specific and non-specific interactions in terms of bond strength or activation energy. The resulting false positive responses lead to various issues, such as misdiagnosis and mistreatment in clinical diagnostics and false alarms in biosecurity. The problem is even more significant with direct direction techniques, such as the resonant frequency shift based detection using quartz crystal microbalance (QCM) or micro-cantilevers, which involve minimal sample processing and washing steps. The work presented in this thesis investigates, through modeling and experiments, the mechanical interactions of a resonator with microparticles attached via biomolecular linkers and analyses the resulting nonlinear acoustic modulation of the resonator from the transduced electrical signal. Physisorbed and specific interactions both in air and liquid medium are studied using thickness shear mode quartz crystal resonators and streptavidin-coated polystyrene microbeads (SCPM) of various sizes. It is found that the modification in the transduced electrical signal measured at the third harmonic (3f), or three times the driving frequency f, is significant in presence of the attached particles and approximately proportional to the number of particles. A detection limit of approximately 2 SCPM of 5.6 µm diameter in air and 6700 SCPM of 0.39 µm diameter in liquid is demonstrated, which corresponds to a mass detection limit of ~200 pg. Most interestingly, the deviation in the magnitude of the 3f signal as a function of the resonator oscillation amplitude is found to hold a distinct relationship with the type of particle-surface interaction. This provides a basis for selectivity in detection over and above the efficacy of the receptor. The function is also found to correlate well with the event of SCPM diffusion on the surface. This detection technique, based on the measurement of deviation in magnitude of the transduced electrical signal measured at a higher odd harmonic of the drive frequency due to the presence of surface-bound particles on a resonator, is termed as the anharmonic detection technique (ADT). A feasibility study with Bacillus subtilis spores in phosphate buffer saline (PBS) is carried out successfully where the modeling and experimental results with SCPM are successfully reproduced. A detection limit of 430 spores is demonstrated, which corresponds to a mass detection limit of ~650 pg. Capability for differentiation of the specifically-captured spores from unwashed physisorbed SCPM of similar dimensions is demonstrated using the shape of the ADT signal. These results indicate that the spore immobilization step may be directly followed by the detection step, which are 9 mins and 2 mins respectively in these experiments. ADT thus potentially enables a rapid, sensitive, reliable and direct detection without the need for any sample processing. Moreover, being an entirely electronic technique, ADT suitably lends itself to multiplexing, large scale fabrication and implementation on a miniaturized low-cost point-of-care detection platform that is of immense need in clinical diagnostics, food and environmental monitoring and biosecurity. Furthermore, fitting the experimental results with modeling estimates enables ADT to determine the force-extension characteristics of the binding biomolecular linker. The force-extension characteristics and the estimated unbinding force for a streptavidin-biotin complex estimated using ADT agrees well with those computed using molecular dynamics (MD) simulation at similar loading rates. Thus ADT contributes a unique force-spectroscopic method, which unlike conventional techniques such as the atomic force microscopy (AFM) provides statistically averaged data for multiple biomolecules in a relatively quicker and simpler experimental format. A method for determination of activation energy of the interaction is also proposed using ADT. This potentially enables a method for rapid and large scale biomolecular screening and studying of interaction networks, which have important applications in drug discovery and individualized therapy.
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Gao, Feng. "An efficient finite element technique for free surface flow." Thesis, University of Brighton, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275077.
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Miller, Pauline Elizabeth. "A robust surface matching technique for coastal geohazard monitoring." Thesis, University of Newcastle Upon Tyne, 2007. http://hdl.handle.net/10443/784.
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Coastal geohazards, such as landslides, mudflows, and rockfalls, represent a major driver for coastal change in many regions of the world, and often impinge on aspects of the human and natural environment. In such cases, there is a pressing need for the development of more effective monitoring strategies, particularly given the uncertainties associated with the impact of future climate change. Traditional survey approaches tend to suffer from limited spatial resolution, while contemporary techniques are generally unsuitable in isolation, due to the often complex coastal topography. To address these issues, this thesis presents the development and application of a strategy for integrated remote monitoring of coastal geohazards. The monitoring strategy is underpinned by a robust least squares surface matching technique, which has been developed to facilitate change detection through the reliable reconciliation of multi-temporal, multi-sensor datasets in dynamic environments. Specifically, this research has concentrated on integrating the developing techniques of airborne and terrestrial laser-scanning. In addition, archival aerial photography has been incorporated in order to provide a historical context for analysis of geohazard development. Robust surface matching provides a mechanism for reliable registration of DEM surfaces contaminated by regions of difference, which may arise through geohazard activity or vegetation change. The development of this algorithm has been presented, and its potential demonstrated through testing with artificial datasets. The monitoring strategy was applied to the soft-cliff test site of Filey Bay, North Yorkshire. This highlighted the viability of the robust matching algorithm, demonstrating the effectiveness of this technique for absolute orientation of DEMs derived from archival aerial photography. Furthermore, the complementary qualities of airborne and terrestrial laser scanning have been confirmed, particularly in relation to their value for multi-scale terrain monitoring. Issues of transferability were explored through application of the monitoring strategy to the hard rock environment of Whitby East Cliff. Investigations in this challenging environment confirmed the potential of the robust matching algorithm, and highlighted a number of valuable issues in relation to the monitoring techniques. Investigations at both test sites enabled in-depth assessment and quantification of geohazard activity over extended periods of time.
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Chivers, Katharine Felicity. "Application of a surface displacement mapping technique to materials problems." Thesis, University of Cambridge, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621768.
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Haque, Ashim Shatil. "Optimization of surface preparation technique for unipolar silicon direct bonding." Thesis, Virginia Tech, 1993. http://hdl.handle.net/10919/41520.
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A special wafer bonding method called the Silicon Direct Bonding technique is
used to study the bonding of unipolar (n-type, <100> oriented) silicon wafers. The
primary objective of this thesis project is to find an optimum surface preparation technique
for subsequent silicon wafer bonding. Wafer cleaning and treatment methods are
investigated to understand the correlation between a high quality wafer surface and the
resulting high quality electrical conduction at the interface. Accordingly, in this project, a
preference for hydrophobic (less polar Si-OH surface) wafers is given to ensure a
minimized amount of oxide layer on the surface. Several key factors that govern the
quality of the wafer surfaces, such as the degree of hydrophobicity, HF etching time,
composition of HF etching solution and Dr water rinse, are examined with ellipsometric
and XPS measurements. An HF etching followed by a sputter etching has been selected to
pre-treat the wafer surfaces for bonding. A maximum allowable air exposure time (35
second) is also found which would allow bonding without significant re-growth of the
oxide layer. Bonding is performed under vacuum with a special mechanical fixture and the
resulting structures from a subsequent heat treatment process are examined with crack
propagation testing. Bond strength after annealing is sufficient to withstand a pull test,
however, with a 3 point bend testing, the crack propagated horizontally at the interface.
Master of Science
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LEE, SANG-KEOL. "THE SURFACE MODIFICATION OF CLAY PARTICLES BY RF PLASMA TECHNIQUE." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1172077740.
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Pozzi, Colakovic Emir. "Monitoring surface cleanliness of manufactured metal parts using camera technique." Thesis, KTH, Industriell produktion, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-232670.
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Technical surface cleanliness is a mandatory requirement for many production lines. It is part ofthe quality control process to ensure that the surfaces of the manufactured components are freeof contaminations and are ready for the next step in the production line. The project has takeninto account two different requirements related to the component cleanliness: first, thecleanliness is measured as the level of contamination on a sample and then, the particles sizes aredetermined. An important factor in the cleanliness is the presence of particles larger than acertain limit, called the critical particles, which have to be detected. This thesis is inspired from anissue SCANIA has (2018) in its production plant in Södertälje, Stockholm. SCANIA has a qualitycontrol system that analyzes the contamination level of few components through a timeconsuming process that takes hours and requires expensive microscopes, human intervention anda dedicated measurement room in the plant. The aim of this thesis is to investigate an alternativetechnical cleanliness monitoring method through the image analysis of the contaminationsamples. Through a simple digital camera, pictures from the contaminated samples are taken,processed and analyzed in order to obtain the cleanliness level and the particles size of thesamples. In contract to the current solution, the proposed method has the possibility of beingimplemented in the production line, providing larger sampling rate.Teknisk ytrenhet är ett obligatoriskt krav för många produktionslinor. Det är en del avkvalitetsstyrningsprocessen för att säkerställa att ytorna på de tillverkade komponenterna är friafrån föroreningar och är redo för nästa steg i produktionslinan. Projektet har tagit hänsyn till tvåolika krav relaterade till komponents renhet: för det första mäts renheten som föroreningsnivå påett prov och sedan bestäms partikelstorlekarna. En viktig faktor vid renhetsbestämning ärnärvaron av partiklar som är större än en viss gräns, som kallas de kritiska partiklarna, som måstedetekteras. Avhandlingen är inspirerad av ett problem SCANIA har (2018) i sinproduktionsanläggning i Södertälje, Stockholm. SCANIA har ett kvalitetskontrollsystem somanalyserar föroreningsnivån av få komponenter genom en tidskrävande process vilken tar timmaroch kräver dyra mikroskop, mänskligt ingripande och ett dedikerat mätrum i anläggningen. Syftetmed denna avhandling är att undersöka en alternativ teknisk renhetsövervakningsmetod genombildanalys av förorenade proverna. Med en enkel digitalkamera tas bilder på de förorenadeproverna, bearbetas och analyseras för att uppnå renhetsnivån och partikelstorleken på proven. Iöverensstämmelse med den nuvarande lösningen finns det möjlighet att implementera denföreslagna metoden i produktionslinan, vilket ger större samplingsfrekvens.
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Pelletier, Eric. "Chaines polymères adsorbées sur surface solide. : Etude statique et dynamique par une technique de forces de surface." Pau, 1993. http://www.theses.fr/1993PAUU3006.
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Les propriétés statiques et dynamiques de solutions de polybutadiène confinées entre une sphère et un plan sont étudiées mécaniquement à l'aide d'un appareil de mesure de forces de surface adapté pour pouvoir opérer comme un rhéomètre à l'échelle moléculaire. La détermination des forces statiques est effectuée à l'aide d'une expérience de drainage entrecoupée d'arrêts à distance fixe. Les propriétés dynamiques sont déterminées par deux méthodes: 1) spectrométrie à distance constante; 2) relaxation de la force apparaîssant lors des arrêts à distance fixe effectués au cours des expériences de drainage. Elles permettent de déterminer les paramètres caractéristiques de la zone d'écoulement terminale. Les différents résultats obtenus pour des solutions allant d'un régime non enchevêtré à un régime légèrement enchevêtré sont corrélés. L'évolution des propriétés du milieu intercalaire avec la concentration et le confinement permet une meilleure compréhension des phénomènes gouvernant les propriétés inter faciales de très fins films.
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Cantarello, Luca. "Use of a Kalman filtering technique for near-surface temperature analysis." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13455/.
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A statistical post-processing of the hourly 2-meter temperature fields from the Nordic convective-scale operational Numerical Weather Prediction model Arome MetCoOp 2.5 Km has been developed and tested at the Norwegian Meteorological Institute (MET Norway). The objective of the work is to improve the representation of the temperature close to the surface combining model data and in-situ observations for climatological and hydrological applications.
In particular, a statistical scheme based on a bias-aware Local Ensemble Transform Kalman Filter has been adapted to the spatial interpolation of surface temperature. This scheme starts from an ensemble of 2-meter temperature fields derived from Arome MetCoOp 2.5 Km and, taking into account the observations provided by the MET Norway network, produces an ensemble of analysis fields characterised by a grid spacing of 1 km. The model best estimate employed in the interpolation procedure is given by the latest avilable forecast, subsequently corrected for the model bias. The scheme has been applied off-line and the final analysis is performed independently at each grid point.
The final analysis ensemble has been evaluated and its mean value has been proved to improve significantly the best estimate of Arome MetCoOp 2.5 km in representing the 2-meter temperature fields, in terms of both accuracy and precision, with a reduction in the root mean squared values as well as in the bias and an improvement in reproducing the cold extremes during wintertime. More generally, the analysis ensemble displays better forecast verification scores, with an overall reduction in the Brier Score and its reliability component and an increase in the resolution term for the zero degrees threshold. However, the final ensemble spread remains too narrow, though not as narrow as the model output.
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Nor, Roslan Md. "A study of ion-surface interactions using a multiphoton ionisation technique." Thesis, Queen's University Belfast, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239215.
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Littman, Nickolas M. "Surface Meta-Materials for Frequency Selection at Microwave Frequencies." Thesis, Griffith University, 2022. http://hdl.handle.net/10072/417688.
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Due to the ever increasing electromagnetic density in our environments, the ability to manipulate radio signals is more important than ever. Specifically, the rise of IoT (internet of things) and 5G has opened up new avenues across various frequency ranges which highlights the need for techniques to control the bandwidth of structures. This thesis explores the use of metamaterials and Frequency Selective Surfaces (FSSs) to design passive, ultra-thin, flexible, broadband structures with unique electromagnetic properties. The research explores the design, modelling, fabrication, and measurement of several structures with different notchbands, with an emphasis on minimising the profile and controlling the bandwidth using passive techniques. A novel fabrication technique was developed to create small, conductive elements on an ultra-thin, flexible, and optically transparent substrate for use in both single and multilayered structures. Laser engraving was used to selectively remove a conductive layer from a dielectric substrate to create an array of conductive elements of prescribed geometry. This method allows for rapid prototyping of surfaces and incurs low fabrication costs, given the process and inexpensive materials used. A technique for bandwidth control of simple loop type bandstop FSSs is explored with the inclusion of additional elements within the same surface. This resulted in the creation of additional resonances resulting in both multiband and broadband responses. The pattern and orientation of an element array was explored, highlighting its importance on controlling the bandwidth, as well as introducing a polarisation dependant response. Further control, and an increase in the bandwidth of bandstop FSSs, were also explored by cascading additional surfaces to create multi-layered structures. These structures incorporated dual elements and a translation between layers to further improve the bandwidth and polarisation stability, with the ability to shift the resonant frequency.
A complex, miniaturized element based on a convoluted square loop element was introduced, and was used in conjunction with the previously explored techniques to create a dual layer structure with dual element translated elements resulting in a -10dB fractional bandwidth (FBW) of 118% along with a frequency reduction of 70%. Ultra-thin and flexible reflection and transmission polarisers operating in the X-band were designed, and applied to structures to significantly increase the bandwidth, whilst minimising the profile of the structure, with the added benefit of being flexible and conformal to curved surfaces. These structures rotate the polarisation of the incident wave through the use of FSS layers and dielectric spacers, where the geometry of the FSS allowed for selection based on the polarisation of the incident wave.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Eng & Built Env
Science, Environment, Engineering and Technology
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Angelico, Vincent James. "The development of a mass spectrometry-based technique that uses low energy ion-surface collisions to characterize surfaces." Diss., The University of Arizona, 2002. http://hdl.handle.net/10150/280148.
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Low energy (tens of eV) ion-surface collisions carried out in a tandem mass spectrometer are investigated as a tool to characterize self-assembled monolayer (SAM) films. The target films are prepared by spontaneous chemisorption of thiol-based (HS-R) compounds onto Au (111) substrates. Most of the films used as targets contain alkane or fluoro-alkane backbones, some with unique groups in the terminal position (e.g., -CD₃, -OH, -OC(O)CF₃). Pyrazine is the most frequently used probe ion, however in certain cases other small organic molecules are also used. Common interactions between the impinging ion and the target film that vary as a function of film characteristics include, but are not limited to, reactive scattering, neutralization and T → V conversion. Pyrazine ion readily reacts when colliding with hydrocarbon films at 20-eV, forming product ions that incorporate a hydrogen atom or a methyl group. Several examples of the utility of these processes to characterize film properties are presented. For hydrocarbon films, ion-surface reactions of pyrazine ion resulting in addition of a hydrogen atom or a methyl group are shown to vary with the quality, chemical composition and orientation of the target film. Experiments with isotopically labeled films show that the ion beam interacts predominantly with the end groups of the film, however interactions with underlying groups increase as the film or substrate quality decreases. The orientation difference of odd and even chain length n-alkanethiols produces a measurably different degree of hydrogen addition with the higher free energy odd chain length orientation being more reactive. The composition of mixed component films (H, D or H, F) is tracked by measuring the abundance of unique reaction products, energy transfer (translational to vibrational conversion) and charge exchange properties. When mixed films containing deuterium labeled and unlabeled n-alkanethiols are subjected to collisions of 20-eV pyrazine ion, the D-addition ion abundance increases linearly with the surface concentration of D-containing alkane chains. When mixed films containing different ratios of H and F components are the target, several processes track with the changing population of surface species. As the target films become more fluorocarbon in nature H-addition decreases, total ion current reaching the detector increases, and dissociation increases. Several properties of electron transfer from the film to the ion are examined. When the probe ion and collision energy remain consant, charge exchange is shown to be primarily governed by the work function of the film and the thickness of the adsorbed layer. Fluorocarbon films, which have a higher work function than hydrocarbon films, consistently show less charge exchange. When comparing hydrocarbon films of varying chain lengths (ranging from 15 to 18 carbons), a increase of ∼1% in total ion current measured at the detector is observed for each additional methylene in the chain.
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Shanmugham, Chetiyar Krishna Kumar, and Venkata Sri Sai Sumanth Galla. "Measurement of Surface Defects in 3D Printed Models." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-32487.
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The ease of manufacturing using additive manufacturing (3D-Printing) reduces the overall production cost compared with the traditional manufacturing techniques. Because of the benefits of 3D printing technologies, it is proposed to be used in manufacturing of different products. But there are some flaws that are causing significant effect on 3D printed models which degrades the quality of the product. Hence in order to handle these defects, different measurement techniques are needed to quantify the defects that are seen on the surface of 3D-printed models. In our study there are two experimental setups. Experimental setup one was made to find out the proper coating timing to enable measurement using two good samples without defects in different colors blue and red with same material. Different 2D and 3D parameters were used for the surface measurements are collected and noted for further research. The Defective samples are measured using the state of the art equipment at Halmstad University. Experimental setup two was made to prepare the defective samples and measure the samples. The results obtained assisted to quantify the surface defects seen in the samples. This thesis studies some of the different methods that can be implemented to measure the surface defects on the 3D printed models. A little study on the various defects formed on the 3D printed models and what are the causes for the defects on the products were performed. The results suggest different method for the defects to be measured in both industrial and home or small scale office applications.
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Bräuer, Pierre. "A multi-technique approach to characterise acidic surface properties of microporous catalysts." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/278651.
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Microporous catalysts belong to a class of materials that exhibit pore networks in the molecular dimension, that is, channel diameters less than 2 nm. The industrially most important microporous catalysts are zeolites, which are crystalline aluminosilicates and consist of interlinked alumina (AlO4) and silica (SiO4) tetrahedra forming pores and cavities of molecular dimensions. Zeolites can act as very strong solid acids and function as heterogeneous catalysts in various industrial processes used to obtain polyethylene terephthalate (PET) or polyvinyl chloride (PVC). They are crucial for products with a significant market demand such as plastics used in bottles, packaging materials and household consumable goods as well as for coatings of pharmaceutical pills and detergents. Recently, zeolites have been found to have increased applications in aqueous and biphasic reactions that use reactants derived from biomass to arrive at petrochemical products. Thus, surface acidity in zeolites is crucial to understand to tune parameters such as activity and selectivity of zeolite catalysts to optimize product distributions. The objective of this dissertation was to validate the use of non-invasive nuclear magnetic resonance (NMR) techniques to characterise surface acidity in zeolites by benchmarking the NMR results to various more established zeolite characterisation techniques, such as Fourier transform infrared (FTIR) spectroscopy and temperature-programmed desorption (TPD). Furthermore, the use of the tapered element oscillating microbalance (TEOM) to characterise internal and external acidity in zeolites was explored. IR and TPD techniques were used to assess important acidity parameters such as type, number, location and strength of acid sites of ZSM-5 zeolites with varying silica-alumina ratio (SAR = SiO2/Al2O3). The use of NMR relaxation time analysis of pyridine adsorbed in ZSM-5 was then explored as a model system to study surface acidity in microporous materials. Correlation with pyridine TPD results suggested that NMR relaxation time analysis probes the effective strength of pyridine adsorption sites, which varies with SAR. NMR relaxation time analysis was then further shown to be applicable to characterise non-acidic surface properties such as the hydrophilic and hydrophobic surface character. Lastly, the NMR techniques developed at high magnetic field strength (300 MHz) were transferred to a portable, low-cost benchtop low-field (43 MHz) magnet and shown to be applicable for base probe molecules other than pyridine, that is, ammonia (NH3) as well as zeolite framework types other than ZSM-5, that is, chabazite (CHA).
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AURIBAULT, DANIEL. "Etude par la technique laser-ultrasons des ondes acoustiques de surface guidees." Paris 7, 1996. http://www.theses.fr/1996PA077164.
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Les ondes acoustiques de surface guidees se propageant dans des guides solides isotropes a geometries classiques (plaque) ou complexes (guides topographiques) presentent des proprietes physiques attrayantes (dispersion, confinement du champ, distribution du champ, etc. ) pour des applications tres diversifiees (controle non destructif, traitement du signal, seismologie, lignes a retard, etc). Dans un premier temps, les ondes guidees par une plaque ont ete etudiees theoriquement par la theorie exacte de rayleigh-lamb et experimentalement par la technique laser-ultrasons, methode tout optique sans contact et large bande. Lorsque la plaque est fine (produit frequence x epaisseur tendant vers zero), un modele a ete etabli. Il decrit correctement, en accord avec la theorie exacte, les modes fondamentaux a#0 (mode de flexion), s#0 (mode dilatationnel) et sh#0 (tranche' de l'onde transversale). Dans un second temps, les ondes guidees par deux guides topographiques, l'arete d'un diedre et l'arete d'une plaque fine, appelees, respectivement, modes antisymetriques de flexion (asf) et pseudo-mode de rayleigh, ont ete examines par des approches theoriques developpees a partir du modele de la plaque fine et par la technique laser-ultrasons appliquee pour la premiere fois a l'etude de ce type d'onde. Les resultats experimentaux en assez bon accord avec la theorie presentee ont mis en evidence un fort confinement du champ et une forte dispersion des modes asf, et un fort confinement du champ et une faible dispersion du pseudo-mode de rayleigh. L'analyse de l'interaction de ce dernier mode avec un milieu ambiant visqueux permet d'envisager la realisation de capteurs de viscosite
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Liu, Jia. "Application of the watershed boundary technique to automatically segment surface froth images." Master's thesis, University of Cape Town, 1995. http://hdl.handle.net/11427/6916.
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Includes bibliographical references.The purpose of this dissertation is to investigate the suitability of using a recently proposed computer processing algorithm - the watershed boundary technique for applications in computer vision systems, where on-line segmentation of the surface froth images in commercial flotation cells is required. In industrial flotation cells, the surface froth offers considerable visual information as to the grade and recovery in extraction and the concentration of minerals in raw ores. The individual bubbles that constitute the surface froth give rise to complex three-dimensional structures that are problematic to segment accurately and reliably by computer vision. Investigating an efficient technique to automatically and accurately extract these visual features in real time is therefore the main task of this research work. Past research work into this field has resulted in a number of different techniques and algorithms for the purpose of segmentation. However, these algorithms are often iterative and therefore quite slow. The technique described here is noniterative and therefore one with industrial real time processing implications. The results show that the watershed boundary technique provides a reliable method for the segmentation of surface froth structures. Minor errors which occur do not significantly influence the statistical parameters which can be determined from the segmented images. This technique is not only very successful in segmentation, but may also be implemented for real-time operation. This clearly leads to a viable new segmentation method.
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Massella, Daniele. "Preparation of biofunctional textiles by surface functionalization based on the nanoencapsulation technique." Thesis, Lille, 2020. http://www.theses.fr/2020LILUI077.
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La présente thèse a été réalisée dans le cadre du projet de doctorat joint SMD-Tex, en partenariat entre le POLITO (Italie), l’ENSAIT (France) et à l'Université de Soochow (Chine). Le but de ce travail est de proposer de nouvelles approches pour la production de textiles biofonctionnels. Ces produits sont constitués de textiles qui ont subi des traitements de finition spéciaux pour conférer des propriétés qui présentent des effets bénéfiques pour la santé de l'utilisateur.Longtemps la recherche pharmaceutique a étudié des outils nouveaux et plus efficaces pour administrer un médicament au patient. Le but de ces études est d’admiistrer des dosages thérapeutiques efficaces sur une longue période, en minimisant le nombre d'administrations requises et les effets secondaires possibles. Dans ce contexte, la peau a été considérée comme une voie de libération de médicaments locaux et systémiques. Une telle approche est plus simple et moins invasive que d'autres voies. Donc, plusieurs stratégies ont été développées pour délivrer efficacement des médicaments à travers la barrière cutanée. Parmi celles-ci, la technologie d'encapsulation permet l'incorporation des substances actives à l'intérieur des nanoparticules (NP) pour i) protéger le médicament, ii) le délivrer efficacement à travers la peau iii) contrôler la libération au fil du temps.Dans le présent travail, des NP chargés de médicament ont été produits en utilisant de la polycaprolactone (PCL) comme membrane. Les nanoparticules produites ont ensuite été utilisées pour le finissage des tissus en coton produisant des textiles biofonctionnels destinés à être utilisés comme dispositifs portables de distribution de médicaments. La technique de nanoprécipitation flash (FNP) a été exploitée pour la production des NPs en raison de sa productivitè, et simplicité. La pertinence du procédé FNP pour produire des NP destinés à être utilisés dans la préparation de textiles biofonctionnels a été étudiée. Les nanoparticules PCL ont été produites en chargeant trois médicaments différents dans le système, à savoir la caféine, la mélatonine et la curcumine. Ces médicaments sont en effet considérés comme des médicaments modèles en termes de niveau d'hydrophilie. Ce dernier est une propriété clé dans la détermination du résultat du processus d'encapsulation et de la perméation cutanée.Le procédé FNP a été exécuté en dissolvant le polymère dans un solvant organique et en faisant entrer le courant de solution en collision avec un courant d'antisolvant dans un micromélangeur, entraînant la précipitation du polymère sous forme de nanoparticules. Pour chaque substance active, les protocoles expérimentaux et les méthodes analytiques ont été ajustés pour mieux étudier le système de NP chargé de médicament. L'effet de la formulation ainsi que les paramètres du procédé sur les taille et la capacité d’enrobement des nanoparticules ont été étudiés. De plus, les formulations de NP ont été caractérisées pour obtenir des informations sur leurs propriétés physiques et chimiques par diverses techniques. Les particules ont été appliquées au textile de coton soit par des méthodes d'imbibition ou d'imprégnation. L'efficacité du traitement de fonctionnalisation a été évaluée en combinant différentes analyses. Les propriétés biofonctionnelles ont été étudiées en termes d'activité antioxydante, de facteurs de protection UV et de libération de médicaments. Pour ce dernier test, la méthode des cellules de Franz a été employée. L'étude a montré que le FNP permet de produire des NPs de PCL chargées de médicament pour les trois substances étudiées. Le traitement de finition proposé a permis de fonctionnaliser efficacement la surface du tissu. Les textiles traités ont permis de délivrer efficacement les principes actifs à la peau avec des profils de perméation dépendant des propriétés du médicament. La finition des nanoparticules confère également au coton des propriétés antioxydantes et de protection contre les UVThis study was performed in the frame of the SMD-Tex Joint Doctorate project. The doctoral research activities were carried out in three mobility periods at POLITO (Italy), Ensait (France), and University of Soochow (China). This work aims to propose novel approaches for the production of biofunctional textiles. These products consist of textile fabrics which underwent special finishing treatments to confer properties that display beneficial effects to the user's health.In the last decades, pharmaceutical research has been investigating novel and more effective tools to administer a drug to the patient. The scope of these studies is to provide effective therapeutic dosages over a long time, minimizing the number of required administrations and the possible side effects. In this context, the skin has been regarded as a potential route for the release of local and systemic drugs. Such an approach is simpler and less invasive compared to other routes. Therefore, several strategies have been developed to effectively deliver drugs across the skin barrier. Among them encapsulation technology allows the incorporation of the active substances inside nanoparticles (NPs) to i) protect the drug, ii) effectively deliver it through the skin iii) control the release over time.In the present work, drug-loaded NPs were produced by employing polycaprolactone (PCL) as shell material. The produced nanoparticles were then used to finish cotton fabrics producing biofunctional textiles to be employed as wearable drug delivery devices. The flash nanoprecipitation technique (FNP) was exploited for the nanocarrier production being identified as a simple, sustainable and efficient production process. The suitability of the FNP process to produce NPs to be used in the preparation of biofunctional textiles was investigated. The PCL nanoparticles were produced by loading three different drugs in the system i.e. caffeine, melatonin, and curcumin. Such drugs are indeed considered model drugs in terms of hydrophilicity level. The latter is a key property in determining the outcome of the encapsulation process and the dermal permeation.The FNP process was run by dissolving the polymer in an organic solvent and making the solution stream collide against an antisolvent stream in a micromixer, resulting in the polymer precipitation in the form of nanoparticles. The drugs were precipitated together with the polymer upon being added either to the solvent or the antisolvent stream. For each active substance, the experimental protocols and analytical methods were adjusted to better investigated the drug-loaded NPs system. The effect of the formulation as well as the process parameters on the properties of the nanoparticles was investigated. The process was optimized to produce particles with a diameter lower than the one of skin pores. The amount of drug loaded in particles was investigated by loading capacity (LC) and encapsulation efficiency (EE). Furtherly, the NP formulations were characterized to obtain insights on their physical, chemical, and morphological properties by various analytical techniques.The particles were applied to the cotton fabric either by imbibition or impregnation methods. The effectiveness of the functionalization treatment was evaluated combining different analyses. The biofunctional properties were studied in terms of antioxidant activity, UV protection factors, and drug release. For the latter test, the Franz cell method was employed using either artificial and excised porcine skin membranes.The study showed that the FNP allows producing drug loaded PCL NPs for all the three investigated substances. The proposed finishing treatment allowed to effectively functionalize the fabric surface. The treated textiles allowed to effectively deliver the active principles to the skin with permeation profiles dependent on the drug properties. The nanoparticle finishing also imparted cotton antioxidant and UV protection properties
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Frayer, Daniel Keith. "Measurement of surface concentration of aqueous copper sulfate solutions: An optical technique." Thesis, The University of Arizona, 2000. http://hdl.handle.net/10150/278740.
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An integrated optical waveguide is described that can measure surface concentrations of ions while immersed in an ionic solution, especially the commercially interesting case of ionic copper. Several such sensors were manufactured and tested. The theory behind this measurement technology is described. Techniques for the manufacture and experimental measurement are described. The devices made were able to measure surface concentrations on the order of 10 12 atoms per square centimeter. Several potential methods for improving the performance are given.
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Chintapula, Uday Kumar. "A-MODE ULTRASOUND TECHNIQUE FOR REGISTERING SKULL SURFACE IN COMPUTER-AIDED SURGERY." OpenSIUC, 2015. https://opensiuc.lib.siu.edu/theses/1669.
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In computer-aided skull surgery such as brain surgery, the goal or target could be fatal even if missed in millimeters. In a Computer Aided surgery (CAS) the subject is registered to the physical space of the subject in the Operating Room (OR). Registration is a process in which physical space is being matched or overlaid on an image space which is generated from Computed Tomography (CT) / Magnetic Resonance Imaging (MRI). Various markers such as anatomic landmarks, temporary attached markers such as titanium screws, etc. are used to optimize the registration process. Markers such as these attachments to the skull are often accompanied with giving local anesthesia, involving invasiveness leading to inconvenience for the patient. To avoid this inconvenience, A-mode (Amplitude mode) Ultrasound technique can be used for the registration of the skull. A-mode ultrasound technique is used to get surface points from the skull. This device works on the principle of echoes received from the junction of two layers with different acoustic impedance, which in this case is the tissue-bone surface. In this project A-mode ultrasound technique is used to obtain surface points from the surface skull and digitize them using software tools such as MATLAB. Using these A-mode ultrasound readings we can apply reconstruction techniques on the digitized points. These results are acceptable and fairly good. A-mode is more accurate and non-invasive.
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MASSELLA, DANIELE. "Preparation of biofunctional textiles by surface functionalization based on the nanoencapsulation technique." Doctoral thesis, Politecnico di Torino, 2020. http://hdl.handle.net/11583/2858355.
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Mayorga, Vera Roberto. "Contribution à la caractérisation des contacts métal-semiconducteurs par la technique des ondes acoustiques de surface." Toulouse, INPT, 1987. http://www.theses.fr/1987INPT018H.
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Presentation d'une methode mettant en jeu l'application des ondes acoustiques de surface pour determiner les caracteristiques d'un semiconducteur et la hauteur de barriere de potentiel d'un contact schottky
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Murugaratnam, Kovthaman. "A refined numerical modelling technique for Shot Peening." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:43e0fa12-bf49-425b-9ba6-6b93adaa8a7e.
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Compressive residual stresses (CRS) are beneficial for enhancing the fatigue life of metal components. Shot Peening (SP) is an industrial cold working process that is applied to induce a field of CRS and modify the mechanical properties of the metal component. The SP process involves impacting a surface with tiny shots with forces sufficient to create plastic deformation. The process is governed by a number of important parameters such as the shot size, angle of attack, initial velocity, mass flow rate and the distance from the shot nozzle to the surface being peened. The relationship between the optimal peening outcome, particularly the residual stress distribution of the treated surface, and the peening parameters is still unknown and needs to be investigated further. Manufacturers are interested in producing a uniform peening process for complex geometries which optimises the SP parameters. Modelling the process is complex as it involves the interaction of a metallic surface with a large number of shots of very small diameter. Conventionally, such problems are solved using finite element software to predict stresses and strains of a single shot impact then applying superposition. At the moment there are no Finite Element Method (FEM) modelling solutions involving more than tens of shots. The number of shots and elements required for such a modelling process made the approach unfeasible prior to the work described herein. The objective of this work is to develop an appropriate numerical modelling approach that can better simulate the real SP process. The model will be provided by combining Discrete Element Method (DEM) with FEM. The DEM is employed to get a distribution of impact velocities over space and time which are then implemented into a FEM analysis. A discrete element model with randomly distributed steel shots bombarding a steel component at various velocities has been developed as benchmark example. With this model the SP shot - shot interaction, the shot - target interaction, the surface coverage, angle of impingement, shot size, impact velocity and the overall shot flow can be parametrically studied in details and with little computational effort. The novel approach also proposes a new method to dynamically change the coefficient of restitution for repeated impacts during the simulation and predicts the CRS more effectively. The effects of SP on different materials of relevance to gas turbine engine components will be investigated in order to improve the understanding of the interaction between the shots and the targeted material. Initially, an uncoupled analysis was peforned, in order to assess the capabilities of the two modelling systems, DEM and FEM, to delivery an improved solutuion when combining two commercially available codes. This parametric analysis is performed using the state-of-the-art Discrete Element (DE) application EDEM. In the subsequent part of this work, a dynamic Finite Element (FE) application Abaqus will be used to investigate single shot impacts and to obtain the residual stress distribution. This gives us a prescribed residual stress distribution and peening coverage. A Combined DEM/FEM tool (DEST) is proposed that eliminates any manual pre-processing required for linking/coupling, eliminating the use of two different applications and provide an integrated solution for the simulation of the Shot Peening process. In the subsequent chapter, the implementation of essential tools for the enchanced modelling of Shot Peening process functionalities, such as the nozzle, bounding box, coverage and intensity is described. A number of computational improvements are also implemented to reduce the computation time. The existing binary search is enhanced to self-balancing search tree and further improved to allow insertion and deletion of elements. A bounding box feature which removes shots that move out of the domain during the course of the simulation is also implemented. Experiments featuring single shot impacts are performed to gain better understanding the deformation process in the target material subjected to impact conditions to those occurring in the production peening. The single shot impacts are experimentally examined using SEM and EBSD. During final chapter, case studies are performed to compare the results of the simulations with large-scale experimental work. The coverage of peening of single and multiple nozzles with different angle of impingements are assessed. Finally, possible directions for further research concerning the accurate quantification of material responses to SP are identified in the report.
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O'Donovan, Paul Christopher. "An investigation of a Fourier based phase retrieval technique used in the analysis of surface fringe patterns." Thesis, Liverpool John Moores University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262107.
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Petat, Bertrand. "Contribution à l'étude de la nitruration du fer par un plasma continu-pulsé." Nancy 1, 1990. http://www.theses.fr/1990NAN10541.
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La nitruration est un traitement thermochimique visant à former à la surface d'une pièce en acier une couche de nitrure (voire de carbo-nitrure) de fer, susceptible d'améliorer de manière notable ses propriétés mécaniques (dureté, résistance à la corrosion, frottement) ainsi qu'une couche de diffusion, siège de contraintes de compression permettrant d'augmenter l'endurance de cette pièce
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Gauffre, Christophe. "Aide au diagnostic routier : vers un outil automatique d'auscultation de la surface des chaussées." Rouen, INSA, 2006. http://www.theses.fr/2006ISAM0021.
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Li, Haifeng. "An evanescent-wave based particle image velocimetry technique." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26472.
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Thesis (Ph. D.)--Mechanical Engineering, Georgia Institute of Technology, 2009.Committee Chair: Yoda, Minami; Committee Member: Aidun, Cyrus; Committee Member: Breedveld, Victor; Committee Member: Fedorov, Andrei; Committee Member: Zhu, Cheng. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Tran, Lucky. "Development of Full Surface Transient Thermochromic Liquid Crystal Technique for Internal Cooling Channels." Master's thesis, University of Central Florida, 2014. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/6371.
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Proper design of high performance industrial heat transfer equipment relies on accurate knowledge and prediction of the thermal boundary conditions. In order to enhance the overall gas turbine efficiency, advancements in cooling technology for gas turbines and related applications are continuously investigated to increase the turbine inlet temperature without compromising the durability of the materials used.
For detailed design, local distributions are needed in addition to bulk quantities. Detailed local distributions require advanced experimental techniques whereas they are readily available using numerical tools. Numerical predictions using a computational fluid dynamics approach with popular turbulence models are benchmarked against a semi-empirical correlation for the friction in a circular channel with repeated-rib roughness to demonstrate some shortcomings of the models used. Numerical predictions varied widely depending on the turbulence modelling approach used. The need for a compatible experimental dataset to accompany numerical simulations was discussed.
An exact, closed-form analytical solution to the enhanced lumped capacitance model is derived. The temperature evolution in a representative 2D turbulated surface is simulated using Fluent to validate the model and its exact solution. A case including an interface contact resistance was included as well as various rib sizes to test the validity of the model over a range of conditions. The analysis was extended to the inter-rib region to investigate the extent and magnitude of the influence of the metallic rib features on the apparent heat transfer coefficients in the inter-rib region. It was found that the thermal contamination is limited only to the regions closest to the base of the rib feature.
An experimental setup was developed, capable of measuring the local heat transfer distributions on all four channel walls of a rectangular channel (with aspect ratios between 1 and 5) at Reynolds numbers up to 150,000. The setup utilizes a transient thermochromic liquid crystals technique using narrow band crystals and a four camera setup. The setup is used to test a square channel with ribs applied to one wall. Using the transient thermochromic liquid crystals technique and applying it underneath high conductivity, metallic surface features, it is possible to calculate the heat transfer coefficient using a lumped heat capacitance approach. The enhanced lumped capacitance model is used to account for heat conduction into the substrate material. Rohacell and aluminum ribs adhered to the surface were used to tandem to validate the hybrid technique against the standard technique. Local data was also used to investigate the effect of thermal contamination. Thermal contamination observed empirically was more optimistic than numerical predictions.
Traditional transient thermochromic liquid crystals technique utilizes the time-to-arrival of the peak intensity of the green color signal. The technique has been extended to utilize both the red and green color signals, increasing the throughput by recovering unused data while also allowing for a reduction in the experimental uncertainty of the calculated heat transfer coefficient. The over-determined system was solved using an un-weighted least squares approach. Uncertainty analysis of the multi-color technique demonstrated its superior performance over the single-color technique. The multi-color technique has the advantage of improved experimental uncertainty while being easy to implement.M.S.M.E.
Masters
Mechanical and Aerospace Engineering
Engineering and Computer Science
Mechanical Engineering; Thermo-Fluids Track
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Huang, Yishi. "New measurement system for studying thermal diffusivity using the transient surface grating technique." Thesis, London South Bank University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298026.
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Skydan, Oleksandr. "New technique for three dimensional surface measurement and reconstruction using coloured structured light." Thesis, Liverpool John Moores University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247723.
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Joyce, Karen Elaine. "Development of Reactive Ion Scattering Spectrometry (RISS) as an Analytical Surface Characterization Technique." Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/193593.
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Reactive ion scattering spectrometry (RISS) utilizing low energy (tens of eV) polyatomic ions was employed to characterize self-assembled monolayers (SAMs) on gold. The terminal composition of halogenated SAMs, chemisorption motifs of disulfide and diselenide SAMs, and electron transfer properties of molecular wire containing SAMs were interrogated to develop the versatility of RISS as an analytical surface characterization technique.Novel halogen terminated SAMs were examined for their ability to convert translational to vibrational energy of colliding projectile ions. A general increasing energy deposition trend correlated with increasing terminal mass with the exception of the iodine functionality. Increased amounts of surface abstractions and sputtering from C12I suggest competitive ion-surface interactions account for less than predicted energy deposition results. Mixed films of CH2Br and CH3 terminal groups elucidated interfacial surface crowding discerned by energy deposition results.Thiol and disulfide based SAMs were shown by RISS comparisons to be dissimilar in structure. Terminal orientation, however, was the same based on ion-surface reactions, disproving the proposed dimer model of disulfide SAMs. Ion-surface reactions and electron transfer properties of disulfide surfaces suggested greater percentages of c(4x2) superlattice structure than in thiol SAMs. Based on increased hydrogen reactivity, decreased methyl reactivity, and increased energy deposition results, diselenide based SAMs were more disordered than S-Au based SAMs. Electron transfer results monitored through total ion currents (TIC) showed Se-Au contacts are more conductive than S-Au attachments.Molecular wire candidates whose electron transfer capabilities are difficult to characterize by traditional techniques were characterized by RISS after being doped into matrix SAMs. Electron transfer properties were dependent on the isolating SAM matrix, dipole moments of the wires, and the potential applied to the surface. Changes in surface voltage dictated molecular wire geometry and electron transfer. Wires were annealed into preferential geometries by colliding ions, but did not operate as switches.While not related to the advancement of RISS, structural elucidation of the pharmaceutical carvidioliol was investigated by collision-induced dissociation, surface-induced dissociation, sustained off-resonance irradiation, and sustained off-resonance irradiation-resonant excitation and through gas-phase hydrogen/deuterium exchange. This molecule fragmented easily by all methods and demonstrated the chemical specificity of gas-phase hydrogen/deuterium exchange experiments.
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Daugherty, Patrick Sean. "Screening combinatorial polypeptide libraries using bacterial surface display and fluorescence-activated cell sorting /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
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Mazière, Bruno. "Corrélation entre gravure et conductivité électrique dans le polyimide (PMDA-ODA) bombardé par un faisceau d'ions." Limoges, 1997. http://www.theses.fr/1997LIMO0040.
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Le bombardement de films de polyimide (13000 nm d'epaisseur) sur support metallique par des ions d'energie intermediaire (gamme des 100 kev) est mis en oeuvre afin : - d'effectuer de la gravure seche ; - d'augmenter la conductivite electrique. La gravure, dans les meilleures conditions, peut atteindre 1,6 microns de profondeur. La conductivite electrique, dans les conditions optimales, passe de 10#-#1#4 s. Cm#-#1 a 10#-#1 s. Cm#-#1. Le regime de conduction dans des bus a echelle millimetrique n'est ohmique que pour certaines conditions d'irradiation. L'ion n#+ est le plus performant, tant pour la gravure que pour la conductivite. L'effet est explique sur la base theorique des collisions (resonance de la fonction gama). L'ensemble des resultats montre que l'irradiation ne peut pas etre modelisee sur le principe classique de l'implantation. Un effet de desorption et de gelification se produit. Le mode de conduction electrique est identifie, et les parametres de description quantitativement evalues. La nature et l'epaisseur de la couche conductrice de surface sont decrites, notamment l'existence possible d'une couche graphitisee, a l'aide de methodes de caracterisation : sims, eels, xps.
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May, Garrett. "A Periodic Technique for Measuring Thermal Properties of Thin Samples." ScholarWorks@UNO, 2007. http://scholarworks.uno.edu/td/603.
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We present a periodic technique for measuring the thermal conductivity and diffusivity of thin samples simultaneously. In samples of this type, temperature measurements must be made across the sample faces and are therefore subject to large error due to the interface resistance between the temperature sensor and the sample. The technique uses measurements of the amplitude and phase of the periodic temperature across both a reference sample and the unknown material at several different frequencies. Modeling of the heat flow in the sample allows the simultaneous determination of the thermal parameters of the sample as well as the interface resistance. Data will be presented for standard materials to show the viability of the technique.
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Alam, Mohammad Anzar. "Online Surface Topography Characterization Technique for Paper and Paperboard using Line of Light Triangulation." Licentiate thesis, Mittuniversitetet, Institutionen för informationsteknologi och medier, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-15967.
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Yellai, Kashyap Williams John R. "Post ion-implantation surface planarization process for 4H-SiC wafers using carbon encapsulation technique." Auburn, Ala., 2006. http://repo.lib.auburn.edu/2006%20Fall/Theses/YELLAI_KASHYAP_13.pdf.
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Bole, Marcus. "A hull surface generation technique based on a form topology and geometric constraint approach." Thesis, University of Strathclyde, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288605.
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Norris, Eleanor. "Surface modification of additively manufactured Ti-6Al-4V using an abrasive vibratory finishing technique." Thesis, University of Bath, 2019. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.767608.
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Additive Manufacturing (AM) enables greater geometrical flexibility in engineering design than conventional manufacturing methods, allowing parts to be customized for individual needs, as well as producing less waste material. However, partially bonded powder particles attached to the surfaces limit the usefulness of parts for a range of engineering applications. In order to enable more widespread use of AM, surface modification techniques are required which allow parts to be suitably finished for the requirements of different applications. Additive Manufacturing (AM) enables greater geometrical flexibility in engineering design than conventional manufacturing methods, allowing parts to be customized for individual needs, as well as producing less waste material. However, partially bonded powder particles attached to the surfaces limit the usefulness of parts for a range of engineering applications. In order to enable more widespread use of AM, surface modification techniques are required which allow parts to be suitably finished for the requirements of different applications. A range of surface modification techniques exist which have been proven capable of improving the surface quality of AM parts. Each technique has its own set of benefits and limitations in terms of surface quality, geometrical flexibility, and the impact of the technique on the material properties. For this reason, there is no one-size-fits-all solution to surface modification for AM. Instead, it has been proposed that these techniques should be treated as a surface modification toolkit, from which techniques can be selected for the individual requirements of a component and its application. This research aims to develop and test a surface modification technique which could address some of the limitations of existing techniques. In this research, a set of candidate techniques are tested during preliminary experimentation, and from these, the Abrasive Vibratory Finishing (AVF) technique is selected for further testing. Experimental and computational techniques are employed to determine the surface modification capability of the technique on AM Ti-6Al-4V. An image processing tool is developed to allow quantification of the removal of partially bonded powder particles from the surfaces. Computational Fluid Dynamics (CFD) is used to gain further knowledge of the process mechanisms, and to understand the impact of different parameters on the technique. The research shows that the AVF technique is capable of removing partially bonded particles from AM components, particularly from surfaces perpendicular to vibratory motion. The surface modification capability can be improved by increasing abrasive grit size. CFD modelling suggests that the process could be further improved by separately varying frequency and velocity of the vibrations. The research has also highlighted the fundamental difference between processing of AM surfaces and non-AM surfaces due to the variation between specimens, and the stress concentration created at the attachment points of individual particles and agglomerates.
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Cheng, Zita Sze Ting. "French surface : a new technique for surface design." Thesis, 2001. http://hdl.handle.net/2429/11669.
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We present a new user-friendly paradigm for surface design. The goal is to overcome limitations
associated with traditional methods: their dependence on freehand controlling and their
rigid mathematical structures. Our solution is inspired by the drafter's tool known as French
curves, which are used as templates for tracing curves. This project considers its analogue in
one higher dimension, namely 3D surfaces. A carefully defined and intuitively arranged set
of French surfaces is given to the user to choose from. The selected surfaces are then connected
together to form the final model.
The potential of this approach is explored with our prototyping system, FRENCH SURFACE,
where models are constructed via aggregated blendings of chosen French surfaces. Triangulated
point-sets are used to engage a structure-free representation, and data structuring algorithms
are integrated to ensure an efficient blending. The current system supports the creation
of objects topologically homeomorphic to a sphere or a plane. Users' experiences demonstrate
that the FRENCH SURFACE system is intuitive, robust, and easy to comprehend.
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Park, Ellane J. "Development of Photochemical Surface Modification Technique." Thesis, 2011. https://doi.org/10.7916/D8JD53SK.
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This thesis will investigate two main areas of surface modification research: I. Designing a photoactive monolayer with improved photo-grafting efficiency. II. Fabrication of NP-Films via phthalimide self-assembled monolayer on glass surfaces. Concluding the thesis, I will briefly describe an outreach research project in collaboration with my GK-12 fellowship team. In Chapter One, we will introduce nanotechnology and surface chemistry, with an emphasis on the use of monolayers for photochemical surface modification. The goal of this chapter is also to equip the reader with a comprehensive overview of common surface analytical techniques and a "how-to" analysis guide for thin films. Chapter Two delves into the fundamentals of SAMs and thin films - the behavior and orientation of adsorbates on surfaces, particularly at air-monolayer interfaces. We discuss the importance of studying the orientation of phthalimide-undecyl-thiol molecules on gold surfaces because the photo-reactivity (i.e. accessibility) of phthalimide terminal groups is dependent on its tilt angle, surface exposure, and packing density. One of the interesting observations includes the possibility that low packing density can potentially have higher photo-grafting efficiency. In Chapter Three, we address the challenge of applying nanoparticles to surfaces. We introduce a fairly well known photochemical surface modification technique to fabricate nanoparticle-films. By using a phthalimide self-assembled monolayer on a glass substrate, we photo-grafted organic nanoparticles to the surface and subsequently, produced a patterned NP-film. Using a photomask allows us to have spatial control and selection on NP-grafting. Lastly, Chapter Four is a brief introduction and overview of the outreach project, studying the heavy metal intake of oysters in the New York Harbor. As a GK-12 fellow, I was given the opportunity to start a research project for the high school students and contribute to the New York Harbor Oyster restoration efforts. The research is focused on detecting heavy metal concentrations in oyster tissue and shells.
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Liu, Gwan-Wun, and 劉冠彣. "Differential surface plasmon resonance sensing technique." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/60326419164133101634.
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碩士國立中央大學
光機電工程研究所
96
An optical differential detection technique for the surface plasmon resonance (SPR) sensing is proposed. In our system, we combine a method of differential detection and SPR technique. The measurement sensitivity of refractive index is about 10-5 RIU (Refractive Index Unit). There are several advantages like immediate detection and high sensitivity in our system. This technique can be applied to the small biological molecule interaction. It is expected to combine the biological molecule on bio-chip array for massive parallel screens.
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HU, CHIA-WEI, and 胡家維. "Study of surface blending and related technique." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/86902042028498880066.
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碩士國立中央大學
機械工程研究所
91
The main purpose of Reverse engineering is reconstructing surface model from the real object. However, in the process of reconstructing surface model, surface connecting technique plays a decisive role, and it is hard to merge Free-from surface in traditional way, especially in complexity and irregular one. For the reason, made the traditional model Digitization by using Mathematics model is more exact and efficient, and comparing to traditional way, using CAD system to edit, design and analyze surface is easier and expeditious. This research focuses on constructing constant radius blending surface of two surfaces. It investigates the need of technique and theory in the process of constructing blending surface and the relation of trimming between blending surface and original surfaces. Trimmed surface represents the surface which has been trimmed, and then analyzing the quality of blending surface from the connecting position of blending surface and original surface and the continuity of slope. Such algorithms, including surface offset and intersection curve of surfaces and it also algorithms the timing and appropriateness of using each calculation.
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Kuo, Shu-Fen, and 郭淑芬. "Improved PSInSAR Technique on Surface Displacement Detection." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/rhf5v3.
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碩士國立臺灣大學
土木工程學研究所
107
According to the investigation report issued by the Water Resources Agency, Ministry of Economic Affairs, there exists continuous subsidence in the Changhua and Yunlin areas of Taiwan. This adverse situation has greatly degraded the performance of local land utilization and the livelihood of inhabitants. In order to effectively address this issue, one must monitor the changes of ground surface elevation, and the solution nowadays is the Interferometric Synthetic Aperture Radar （InSAR）technique which has the advantage of broad area coverage, high measurement accuracy, and all-weather operations. The Differential Interferometric Synthetic Aperture Radar （DInSAR） and Persistent Scatterers InSAR（PSInSAR） techniques take two or more SAR images collected from different times and viewing angles over the same geographical location into the interferometric processing where the phase differences and small changes between images are extracted to render the information on geographical changes. However, for areas where the density of stabilized radar wave scatterers is low, such as flat terrain or lush vegetation, due to few fixed structures, the DInSAR and PSInSAR techniques may not function satisfactorily. To alleviate this limitation, the present study improves the differential SAR interferometry where the SAR images are first processed using PSInSAR technique to determine Persistent scatterer candidates （PSC）and then the images are further processed using statistical analyses such as Kolmogorov-Smirnov test, Cramer-von Mises test, Anderson-Darling test and correlation coefficient to acquire Distributed scatterer candidates （DSC）. By processing these scatterer candidates, the present study establishes ground subsidence displacement and velocity for the Tuku Township of Yunlin County using Sentinel-1A SAR satellite images of European Space Agency from 2016 to 2017.
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Ming-HanChuang and 莊明翰. "Surface Wave Measurement Using Binocular Stereo Imaging Technique." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/40394297414717774777.
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Siao, Yi-fan, and 蕭逸凡. "Detection of Surface Displacements by a PSInSAR Technique." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/15119260338239514732.
Full textAbstract:
碩士國立中央大學
土木工程研究所
98
Repeat-pass satellite Interferometric SAR(InSAR) is potentially a unique tool for low cost precise Digital Terrain Model(DTM) generation and large-coverage surface deformation monitoring. Differential InSAR(DInSAR) may be used to monitor centimeter-scale surface displacements over large geographic extents. However, the method has limitations set by temporal and geometric decorrelation and atmospheric inhomogeneities. We present a Persistent Scatterer(PS) InSAR method for analyzing episodic crustal deformation in non-urban environments. This method for identifying PS pixels in a series of interferograms is based primarily on coherence index and finds low-amplitude pixels with phase stability that are not identified by the existing amplitude-based algorithm. The model which considers linear velocity deformation and DTM error usually using a centre target’s range distance. This method is fit for a test area nearby a centre area, but it’s not suitable for Taiwan’s urban. Taiwan’s urban usually locate in side of SAR images, that let a centre area’s value see not suitable. We chose adaptable range distance instead the fixed value. Using this method, we identified a density of 4.1 PS/km2. Even for longer than 500 m baselines, the PSInSAR technique can help build land subsidence maps better than differential InSAR does.
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Lee, Morjin, and 李昇峻. "A Surface Wave Analysis Technique for Crack Sizing." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/46571959700782239259.
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碩士大葉大學
電機工程學系碩士班
92
In this study, a method of surface wave inspection is approached to detect an object’s surface condition. Surface wave inspection is performed by emitting ultrasonic waves along the surface of the object, and then according to the acquired property values of wave reflection, to determine whether if there is an existence of abnormal surface condition, for example, a fissure.During the employment of ultrasonic wave aiming to detect possible fissure, multiple reflective signals are returned and recorded. By analyzing these signals, formation of path composition by various waves is then formulated. Furthermore, these signals are proved to be a useful tool to double check for accuracy of the fissure height. By combining the results drawn from the above analyses, mean and standard deviation for multiple estimates are derived, as well as the confidence level. In conclusion, it follows from what has been said that, accurate fissure height derived from surface wave inspection is an applicable index for equipment safety and maintenance analyses.
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Chiu, Che-an, and 邱徹安. "-- “Rubbing film” –The technique of skin surface inspection." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/k22v94.
Full textAbstract:
碩士嘉南藥理科技大學
藥物科技研究所
97
Abstract Whether the skin is healthy or not, it has its unique veins, such as prematurely、irritable、wrinkle、twinge…., and even though they are in different forms, they have never been showed completely. “Rubbing film” is a technique which can more faithfully indicate the condition of the skin than SEM, for the reason that it does not have to have the procedure of gilding, but receive the message from the skin directly and turn it into an image. The quality of the image is as well as SEM, and with an easy reading procedure, the type of the skin can be discerned. This research also utilize “ Rubbing film” to reveal the skins that may be prematurely、irritable、wrinkle or twinge. Up to the present, image tools are unable to be the quantitative tools on skin researches; however, there is also a breakthrough of the defect by “Rubbing film”. It utilizes the different traits of skin as a statistical standard, and turns the standard into statistic figures, enables it to be appropriate for big or small scales and long-term or short-term researches, such as researches about the dermal difference before and after a laser surgery or long-term of using fruit acid. (This article will be described clearly in chapter 4) “Rubbing film” use polymer colloid as a sampling tool and the rubbing film can be preserved and collected for a long time after sampling, which is cannot be easily impaired. These traits are necessary terms for long-term or short-term researches. In addition, it is easy to operate, and its non-invasion trait can decrease all kinds of limit on the research. Therefore, it is very useful to the research about handling the variety of the skin which needs to be fast and accurate. As far as the dermal researchers are concerned, “ Rubbing film” is very persuasive、well-reconstructed、can be easily read and the researching result of quantification can be easily compared. Besides, it is highly objective、low cost, and it possesses an advantageous position which is superior to other tools. There are all kinds of apparatus of skin determination. In order to handle skin variety accurately, and to observe with our eyes directly, “Rubbing film” is a more convenience selection than SEM. If it can be collocate with other researching equipments, the credibility and proving power can exalt the result of the research. Key word: skin surface analysis, skin replica, negative replica, silicone replica
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林鴻昱. "Measurement Technique of the Smoothness of Curved Surface." Thesis, 1989. http://ndltd.ncl.edu.tw/handle/46692405618855675450.
Full textAbstract:
碩士國立臺灣大學
機械工程研究所
77
SMC (Sheet Moulding Compound) is a kind of fiber reinforced plastic material. It has several features: such as high strength, light weight, and ease of forming. It has been applied to various areas, such as car body, pressure vessel, and so on. The surface of SMC may be flat or curved. Under good forming conditions, the smoothness of the surface can be properly controlled. A precision system to inspect the surface smoothness is also needed. The conventional method using profilemeter may very often scratch the surface of SMC. Besides, its speed is too slow to use. This thesis develops a non-contact measuring system for surface smoothness. By the use of a dual-axis scanner, a laser line can be projected onto the test piece, and scanned across the surface. A CCD camera is then employed to capture the image of the reflected line on a screen. The distortion of projected image can be related to the surface smoothness based on proposed mathematical model. Through image processing technique, the smoothness can be directly repressented by index value, and then classified by different grades.
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Huang, Chen-Fu, and 黃振福. "A Study of the Dual Response Surface Technique." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/53921969424158814319.
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