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Dissertations / Theses on the topic 'Surface'

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Published: 4 June 2021
Last updated: 26 April 2025

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1

Chen, Yizhou. "Adhesion of Spider Glue on Different Surface Energy and Surface Potential Surfaces." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1462227997.

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2

Kruithof, Nico Gerard Hugo. "Envelope surfaces surface design and meshing /." [S.l. : [Groningen : s.n.] ; University Library Groningen] [Host], 2006. http://irs.ub.rug.nl/ppn/292152264.

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3

Johansson, Lars. "SURFACE DRAG MODELING FOR MILLED SURFACES." Thesis, KTH, Mekanik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-204017.

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One of the governing sources of energy loss in a modern day jet engine is attributed to surfacedrag. This energy loss can be divided into friction loss and to surface geometry loss. Thefriction loss is the shear stress the fluid experience due to a no slip condition at the wall, whilethe surface geometry loss is due to pressure drop when the fuel passes an obstacle.The objective of this work is to study the drag coefficient of a plate for different types ofmilled tracks and for different kinds of flow conditions. The theories used to calculate thedrag coefficient are based on the momentum thickness theory including shear stress- andpressure integration. The computations were carried out with ANSYS CFX assuming a ShearStress Transport 𝑘 − 𝜔 turbulence model. The steady state flow conditions tested are varyingboundary layer thicknesses, milled track heights, milled track widths, Reynolds numbers overthe milled track height, Reynolds numbers over the plate length and free-stream angle ofattack. By knowing what affects the drag coefficient for different types of milled tracks, morepractical models can be developed making the prediction of surface drag inside the jet enginemore accurate.This report has resulted in a formula that predicts the drag coefficient for different types ofmilled surfaces. The formula is derived from the assumption that the CFD results on ANSYSCFX are correct. A physical test has not been made to verify those results, however this has tobe done to prove that this formula is valid.
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4

Shukla, Nisha. "Surface spectroscopic studies of coadsorbed molecules and surface reactions at single crystal metal surfaces." Thesis, Cardiff University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275212.

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5

Zheleva, Zhasmina Vasileva. "Surface crystallography of complex and disordered surfaces." Thesis, University of Reading, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.553057.

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6

Mansfield, Mark. "Surface stress and reconstructions on metal surfaces." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359866.

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7

Myshlyavtsev, Alexander V., and Marta D. Myshlyavtseva. "Modeling of surface diffusion for stepped surfaces." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-193477.

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8

Lee, Chee-kwan. "Modelling of flexible surfaces using a point mass system /." [Hong Kong : University of Hong Kong], 1992. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13204889.

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9

Zhang, Jinhong. "Surface Forces between Silica Surfaces in CnTACl Solutions and Surface Free Energy Characterization of Talc." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/29997.

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In general, the stability of suspension can be studied using two methods. One is to directly measure the forces between two interacting surfaces in media. The other is to study the interfacial surface free energies of the particles in suspension. Direct surface force measurements were conducted between silica surfaces in octadecyltrimetylammonium chloride (C₁₈TACl) solutions using an Atomic Force Microscope (AFM). The results showed that the hydrophobic force existed in both air-saturated and degassed C₁₈TACl solutions. The attraction decreased with NaCl addition, and was the strongest at the point of charge neutralization (p.c.n.) of silica substrate. The force measurement results obtained in CnTACl solutions showed that the attractions decayed exponentially and became the maximum at the p.c.n.'s. The decay lengths (D) increased with surfactant chain length. The measured forces were fitted to a charged-patch model of Miklavic et al. (1994) with rather large patch sizes. It was also found that the decay length decreased linearly with the effective concentration of the CH2/CH3 groups raised to the power of -1/2. This finding is in line with the model of Eriksson et al. (1989). It suggested that the long-range attractions are hydrophobic forces originating from the changes in water structure across a hydrophobic surface-solution interface. For the TiO₂/water/TiO₂ system, the Hamaker constant was found to be 4±1×10-20 J. The force curves obtained in the TiO₂/CnTACl system showed a repulsion-attraction-repulsion transition with increasing surfactant concentration. The long-range attraction observed between TiO₂ surfaces in CnTACl solutions reached maximum at the p.c.n., and the decay length increased with chain length. In present work, the thin-layer wicking technique was used to determine the surface free energy (γs) and its components of talc samples. The results showed that the basal surfaces of talc are weakly basic while the edge surfaces are acidic. The effect of chemicals on the surface free energies of talc was systemically studied. The results showed that CMC (carboxymethyl cellulose sodium salt) and EO/PO (ethylene oxide/propylene oxide) co-polymers made talc surface hydrophilic by increasing the surface free energies, especially γLW and γ -. SOPA (sodium polyacrylate) increased greatly the zeta-potentials instead of the surface free energies.
Ph. D.
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10

Dalpé, Denis. "Schwarz's surface and the theory of minimal surfaces." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0023/MQ39958.pdf.

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11

Roach, Paul. "Measurement of surface-protein interactions on novel surfaces." Thesis, Nottingham Trent University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.431900.

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This thesis is concerned with the fundamental principles affecting protein adsorption. The effects of surface chemistry and topography on protein adsorption characteristics have been identified and quantified. Particular attention has been made to understand how the conformation of surface-bound proteins was affected by the surface onto which they adsorbed. Quartz crystal microbalance (QCM), UV-Vis spectroscopy and fluorometry were used to assess protein-surface affinity and amounts of protein adsorbed at surface saturation levels. Infrared spectroscopy was used to quantify protein conformational changes incurred upon adsorption. A fluorescent assay protocol was developed for use as an external calibration method for the quantification of adsorbed protein an d the results obtained were compared with QCM and an amido black protein assay of the same systems. Model experiments were performed using bovine fibrinogen (an elongated molecule) and albumin (a globular molecule) adsorbing onto flat hydrophilic (OH terminated) and hydrophobic (CH3 terminated) surfaces in the first instance, but later superhydrophilic and superhydrophobic surfaces were also studied. Surface curvature on the nano-scale was used to model topography, wherein protein molecules adsorbed onto spherical substrates (15-165 nm diameter) having chemically defined surfaces. Results obtained indicate that both proteins exhibit a less organised secondary structure upon adsorption onto hydrophobic compared to hydrophilic surfaces, with this effect being greatest for albumin. Adsorption rates and binding affinities were found to be higher on hydrophobic surfaces although the amounts adsorbed at saturation were lower. Supporting spectroscopic data suggests that proteins undergo surface induced deformation upon adsorption. Topography was shown to compound the effects of surface chemistry, with fibrinogen being more denatured on surfaces presenting high surface curvature whereas albumin was more denatured on larger substrates. These effects are most probably due to the differing size and shape of the proteins investigated. This study highlights the possibility of using tailor-made surfaces to influence binding rates and the conformation of bound proteins through protein-surface interactions. The data presented in this thesis demonstrates our ability to control protein adsorption characteristics through careful consideration of the underlying surface, which may facilitate the development and fabrication of materials / surface coatings with tailored bioactivity.
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12

Severn, Kathryn A. "Science of synthetic turf surfaces : player-surface interactions." Thesis, Loughborough University, 2010. https://dspace.lboro.ac.uk/2134/7216.

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This research project has investigated the mechanical properties and behaviour of third generation synthetic turf surfaces used for football and rugby, with a focus on the traction behaviour produced at the shoe-surface interface. The physical characteristics and mechanical properties of the component materials used in the construction of third generation surfaces were examined. The bulk density of the rubber infill material was found to be a key variable. This was shown to be influenced by compaction and the resulting compression of the rubber infill material under an applied load. Increasing the compactive effort and/or compression under loading increased the bulk density. Shear strength of the rubber infill material was shown to be influenced by bulk density, increasing with a higher bulk density. The composite surface system behaviour of third generation synthetic turf surfaces was investigated. Several surface variables were measured including; shockpad thickness, synthetic turf carpet construction, infill thickness, infill bulk density and infill material type. Shockpad thickness, rubber infill thickness and bulk density were found to influence the impact behaviour, with a thicker rubber layer (shockpad and/or rubber infill layer) reducing the hardness of a surface system. Increasing the bulk density of the rubber infill with compactive effort increased the surface system hardness. Traction behaviour of composite surface systems was explored using three traction test methods to measure both rotational and translational traction. Rubber infill bulk density was shown to be a primary influencing variable from the playing surface variables investigated. Several further traction variables were explored to provide a fuller understanding of the mechanisms involved in the production of traction at the shoe-surface interface including; vertical stress, stud configuration, stud dimension, stud penetration, water and temperature. Vertical stress and stud configuration were found to be primary variables influencing traction development. A traction framework has been developed identifying the factors affecting the production of traction at the shoe-surface interface. It is intended that the traction framework can be used by the sports surface industry, sports governing bodies and academia to aid in the decisions and judgements made during the design, construction and maintenance of these surfaces to obtain desired characteristics and optimise performance and safety.
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13

Wang, Jialin. "AFM surface force measurements between hydrophobized gold surfaces." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/29031.

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In 1982, Israelachvili and Pashley reported the first measurements of a hitherto unknown attractive force between two mica surfaces hydrophobized in cetyltrimethylammonium bromide (CTAB) solutions. Follow-up experiments conducted by many investigators confirmed their results, while others suggested that the â hydrophobic forceâ is an artifact due to nanobubbles (or cavitation). Evidences for the latter included the discontinuities (or steps) in the force versus distance curves and the pancake-shaped nano-bubbles seen in atomic force microscopic (AFM) images. Recent measurements conducted in degassed water showed, however, smooth force versus distance curves, indicating that the hydrophobic force is not an artifact due to nanobubbles.1, 2 Still other investigators3, 4 suggested that the long-range attraction observed between hydrophobic surfaces is due to the correlation between the patches of adsorbed ionic surfactant and the patches of unoccupied surface. For this theory to work, it is necessary that the charged patches be laterally mobile to account for the strong attractive forces observed in experiment. In an effort to test this theory, AFM force measurements were conducted with gold substrates hydrophobized by self-assembly of alkanethiols and xanthates of different chain lengths. The results showed long-range attractions despite the fact that the hydrophobizing agents chemisorb on gold and, hence, the adsorption layer is immobile. When the gold surfaces were hydrophobized in a 1 à 10-3 M thiol-in-ethanol solution for an extended period of time, the force curves exhibited steps. These results indicate that the long-range attractions are caused by the coalescence of bubbles, as was also reported by Ederth.5 The steps disappeared, however, when the species adsorbed on top of the chemisorbed monolayer were removed by solvent washing, or when the gold substrates were hydrophobized in a 1 à 10-5 M solution for a relatively short period of time. AFM force measurements were also conducted between gold substrates coated with short-chain thiols and xanthates to obtain hydrophobic surfaces with water contact angles (ï ±) of less than 90o. Long-range attractions were still observed despite the fact that cavitation is thermodynamically not possible. Having shown that hydrophobic force is not due to coalescence of pre-existing bubbles, cavitation, or correlation of charged patches, the next set of force measurements was conducted in ethanol-water mixtures. The attractive forces became weaker and shorter-ranged than in pure water and pure ethanol. According to the Derjaguinâ s approximation6, an attractive force arises from the decrease in the excess free energy (ï §f) of the thin film between two hydrophobic surfaces.7 Thus, the stronger hydrophobic forces observed in pure water and pure ethanol can be attributed to the stronger cohesive energy of the liquid due to stronger H-bonding. Further, the increase in hydrophobic force with decreasing separation between two hydrophobic surfaces indicates that the H-bonded structure becomes stronger in the vicinity of hydrophobic surfaces. The force measurements conducted at different temperatures in the range of 10-40ºC showed that the hydrophobic attraction between macroscopic surfaces causes a decrease in film entropy (Sf), which confirms that the hydrophobic force is due to the structuring of water in the thin film between two hydrophobic surfaces. The results showed also that the hydrophobic interaction entails a reduction in the excess film enthalpy (Hf), which may be associated with the formation of partial (or full) clathrates formed in the vicinity of hydrophobic surfaces. The presence of the clathrates is supported by the recent finding that the density of water in the vicinity of hydrophobic surfaces is lower than in the bulk.8
Ph. D.
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14

McLaughlin, Keith. "Toward understanding low surface friction on quasiperiodic surfaces." [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0003161.

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15

GALLIS, CORALIE. "Couplage entre ordre de volume et segregation de surface : des surfaces d'alliage aux alliages de surface." Paris 6, 1997. http://www.theses.fr/1997PA066341.

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La connaissance des surfaces d'alliages est essentielle pour comprendre leurs proprietes catalytiques. La determination de la stabilite des alliages de surface, objets metastables depend fortement des caracteristiques des surfaces des alliages a#cb#1#-#c, d'une part. D'autre part, la connaissance des cinetiques de formation-dissolution des alliages de surface peut permettre de connaitre les isothermes de segregation d'equilibre. Nous avons ainsi pu explorer le lien entre l'equilibre de segregation d'un alliage a#cb#1#-#c et la cinetique de dissolution de quelques monocouches de a/b ou du depot inverse. Pour cela, nous avons utilise un modele energetique derive de la structure electronique t. B. I. M. , nous permettant l'etude tant dans l'etat desordonne que dans l'etat ordonne des isothermes d'equilibre de segregation. Les cinetiques de dissolution ont ete explorees a l'aide de la version cinetique du modele (k. T. B. I. M. ) compatible avec le modele d'equilibre. Afin d'illustrer notre etude, nous avons choisis le systeme cu-pd, systeme modele quant a la formation d'alliages de surfaces et pour lequel de nombreuses etudes tant experimentales que theoriques sont entreprises. Nous avons ainsi montre pour la surface (111) de ce systeme que les alliages de surfaces obtenus au cours des cinetiques de dissolution sont directement relies aux surfaces d'alliages obtenues lors de l'equilibre de segregation. Le systeme cu-pd est caracteristique de systemes a faibles moteurs de segregation. Nous avons donc entrepris une etude equivalente pour un systeme dont les forces motrices de la segregation sont plus importantes. Notre choix s'est porte sur le systeme pt-sn. Le comportement de la surface tant a l'equilibre que lors des cinetiques de dissolution s'est avere particulierement differents du premier systeme et en particulier, des alliages de surfaces typiques ont ete mis en evidence. Enfin, une etude par dynamique moleculaire trempee a permis de determiner la stabilite relative des diverses surstructures de surfaces possibles.
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16

Sasián, José, Dmitry Reshidko, and Chia-Ling Li. "Aspheric/freeform optical surface description for controlling illumination from point-like light sources." SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS, 2016. http://hdl.handle.net/10150/622704.

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We present an optical surface in closed form that can be used to design lenses for controlling relative illumination on a target surface. The optical surface is constructed by rotation of the pedal curve to the ellipse about its minor axis. Three renditions of the surface are provided, namely as an expansion of a base surface, and as combinations of several base surfaces. Examples of the performance of the surfaces are presented for the case of a point light source. (C) 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)
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17

Greene, George W. IV. "Surface modification of sintered porous polyethylene membrane." Thesis, Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/20126.

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18

Ou, Meigui. "Nanostructured gold surfaces as biosensors : surface-enhanced chemiluminescence and double detection by surface plasmon resonance and luminescence." Lyon, INSA, 2008. http://theses.insa-lyon.fr/publication/2008ISAL0057/these.pdf.

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This thesis is devoted to develop two biological detection systems based on nanostructured gold surfaces to detect the binding of streptavidin/biotin. In the first part, we have studied a multimodal detection system using local surface plasmon resonance of the gold substrate and the luminescence of labelling core-shell Gd2O3/SiOx nanoparticles, which profits from the plasmonic property of nanostructure gold. In a second part, we have focused in a surface-enhanced chemiluminescence system based on chemiluminescence of luminal/hydrogen peroxide (H2O2) enhanced by gold nanostructures in the vicinity, which benefits from the catalytic property of nanostructure gold. Several parameters influencing the chemiluminescence of luminal were investigated. Enhancing mechanism of luminal chemiluminescence was proved to be not related to Plasmon-assisted process but originates from catalytic properties of the metal induced by corrugation
Cette thèse est consacré à développer deux systèmes pour la détection biologique à la base de la surface d’or pour détecter la liaison entre les molécules de biotine et de streptavidine. Premièrement, nous avons étudié un système de détection multimodal utilisant la résonance des plasmons de surface localisé sur substrats d’or et la luminescence de nanoparticules labellisées de coeur-écorce Gd2O3/SiOx, qui bénéficie de la propriété plasmonic d’or en nanostructure. Deuxièmement, nous avons focalisé sur un système qui se fonde sur le phénomène d’exaltation de chimiluminescence par la surface. La chimiluminescence de luminophore/ peroxyde d’hydrogène (H2O2) est exaltée par nanostructure d’or à proximité, qui bénéficie de la propriété catalytique de nanostructure d’or. Plusieurs paramètres ont été étudiés de manière systématique. Finalement, il est prouvée que le mécanisme de l’exaltation de chimiluminescence est originaire de la propriété catalytique du métal induit par la rugosité
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19

Tidwell, Caren Diana. "Endothelial cell interactions with model surfaces : effect of surface chemistry, surface mobility, and the adsorbed protein layer /." Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/8004.

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20

Cole, D. J. "Surface chemistry and adhesive properties of oxidised Si surfaces." Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.597835.

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I have used density functional theory and classical molecular dynamics to study the chemistry of the native oxide layer on the Si(100) surface. Surface oxidation is accompanied by the development of tensile surface stress and by formation of Si species with a range of oxidation states. Total energy calculations of P and B substitution into the oxide layer and first principles molecular dynamics simulations of oxide growth on the doped surface both indicate a surface oxidation mechanism whereby impurities remain trapped at the Si/SiOx interface. A new two- and three-body classical potential is developed to simulate the hydroxylated, natively oxidised Si surface in contact with water solutions and biological molecules. The potential parameters are chosen to reproduce the structure, charge distribution, tensile stress and interactions with single water molecules of a natively oxidised Si surface previously obtained by ab initio simulations. I apply this classical potential to study the atomic-level processes that determine the mutual adhesion between hydrophilic Si wafers during room temperature bonding. Moreover, I have investigated the adhesion mechanisms of proteins such as collagen and human serum albumin, which mediate the interactions between cells and implanted Si-based devices.
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21

Plaisance, Marc Charles. "Cellular Response to Surface Wettability Gradient on Microtextured Surfaces." Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/53730.

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Objective: Topography, chemistry, and energy of titanium (Ti) implants alter cell response through variations in protein adsorption, integrin expression, and downstream cell signaling. However, the contribution of surface energy on cell response is difficult to isolate because altered hydrophilicity can result from changes in surface chemistry or microstructure. Our aim was to examine a unique system of wettability gradients created on microstructured Ti on osteoblast maturation and phenotype. Method: A surface energy gradient was created on sand-blasted/acid-etched (SLA) Ti surfaces. Surfaces were treated with oxygen plasma for 2 minutes, and then allowed to age for 1, 12, 80, or 116 hours to generate a wettability gradient. Surfaces were characterized by contact angle and SEM. MG63 cells were cultured on SLA or experimental SLA surfaces to confluence on TCPS. Osteoblast differentiation (IBSP, RUNX2, ALP, OCN, OPG) and integrin subunits (ITG2, ITGA5, ITGAV, ITGB1) measured by real-time PCR (n=6 surfaces per variable analyzed by ANOVA/Bonferroni’s modified Student’s t-test). Result: After plasma treatment, SLA surface topography was retained. A gradient of wettability was obtained, with contact angles of 32.0° (SLA116), 23.3° (SLA80), 12.5° (SLA12), 7.9° (SLA1). All surfaces were significantly more hydrophilic than the original SLA surface (126.8°). Integrin expression was affected by wettability. ITGA2 was higher on wettable surfaces than on SLA, but was highest on SLA1. ITGAV and ITGB1 were decreased on hydrophilic surfaces, but ITGA5 was not affected. IBSP, RUNX2, and ALP increased and OPG decreased with increasing wettability. OCN decreased with increasing wettability, but levels on the most wettable surface were similar to SLA. Conclusion: Here we elucidated the role of surface energy on cell response using surfaces with the same topography and chemistry. The results show that osteoblastic maturation was regulated in a wettability-dependent manner and suggest that the effects are mediated by integrins.
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22

Ye, Fan. "Surface plasmon polaritons along metal surfaces with novel structures." Thesis, Boston College, 2014. http://hdl.handle.net/2345/bc-ir:103747.

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Thesis advisor: Michael J. Naughton
Surface plasmon polaritons (SPPs) are hybridized quasiparticles of photons and electron density waves. They are confined to propagate along metal-dielectric interfaces, and decay exponentially along the direction perpendicular to the interfaces. In the past two decades, SPPs have drawn intensive attention and undergone rapid development due to their potential for application in a vast range of fields, including but not limited to subwavelength imaging, biochemical/biomedical sensing, enhanced light trapping for solar cells, and plasmonic logic gates. These applications utilize the following intrinsic properties of SPPs: (1) the wavelength of SPPs is shorter (and can be much shorter) than that of free photons with the same frequency; (2) the local electric field intensity associated with SPPs can be orders of magnitude larger than that of free photons; and (3) SPPs are bound to metal surfaces, and are thus easily modulated by the geometry of those surfaces. Here, we present studies on SPPs along metal surfaces with novel structures, including the following: (1) SPP standing waves formed along circular metal surfaces that lead to a "plasmonic halo" effect; (2) directional reflectionless conversion between free photons and SPPs in asymmetric metal-insulator-metal arrays; and (3) broadband absorbance enhancement of embedded metallic nanopatterns in a photovoltaic absorber layer. These works may prove useful for new schemes for SPP generation, plasmon-photon modulation, ultrasensitive dielectric/bio sensing, and high efficiency thin film solar cells
Thesis (PhD) — Boston College, 2014
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Physics
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23

Soldemo, Markus. "Transition metal oxide surfaces : Surface structures and molecular interaction." Doctoral thesis, KTH, Materialfysik, MF, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-196130.

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Metal oxides are both corrosion products and useful materials with a wide range of applications. Two of the most used metals today are iron and copper. In this thesis, surface structures and molecular interaction with surfaces of iron oxides and copper oxides are studied using spectroscopy and microscopy methods.   The surface structures of iron oxides grown on the low-index iron (Fe) surfaces (100) and (110) have been studied during the initial oxidation phase. The oxidation condition for both iron surfaces was 400 °C and 1×10−6 mbar of oxygen gas. For the Fe(100)-surface, a Fe3O4(100)-film is formed beyond the oxygen adsorbate structures. For the Fe(110)-surface, a FeO(111)-film is first formed. When the FeO(111)-film grows thicker, it transforms into a Fe3O4(111)-film.   The surface structures of Cu2O(100) was studied and the main finding is that the most common surface structure that previously in literature has been described to have a periodicity of (3√2×√2)R45° actually has a periodicity described by the matrix (3,0;1,1). Furthermore, the low-binding energy component in the photoelectron spectroscopy O 1s-spectrum is determined to origin from surface oxygen atoms.   Sulfur dioxide, a corrosive molecule that in the environment to large share comes from human activities such as burning of fossil fuels, was studied using photoelectron spectroscopy when interacting with surfaces of iron oxide thin films and bulk Cu2O-surfaces. On the iron oxide thin film surfaces under ultra-high vacuum conditions, sulfur dioxide adsorbs partly as SO4-species and partly dissociates and forms FeS2. On the Cu2O-surfaces under ultra-high vacuum conditions, the adsorption of sulfur dioxide is non-dissociative and forms SO3-species. When interacting with near-ambient pressures of water, it is observed in the photoelectron spectroscopy S 2p-region that the sulfur from SO3-species shifts to Cu2S.

QC 20161114

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24

Chakrabarty, Souvik. "NOVEL SOFT SURFACES WITH INTERESTING SURFACE AND BULK MORPHOLOGY." VCU Scholars Compass, 2012. http://scholarscompass.vcu.edu/etd/397.

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The goal of this research is to cover a broad set of scientific investigations of elastomeric materials based on polydimethylsiloxane (PDMS) and poly((3,3,3-trifluoroethoxymethyl)methyloxetane) diol. The scope of study covers five areas, well correlated with each other. The first study investigates the near surface morphology of condensation cured PDMS as a function of increasing the amount of siliceous phase. The appearance, disappearance and reappearance of untreated fumed silica nanoparticles at the PDMS near surface and their correlation with the volume fraction of siliceous phase have been studied. This research with PDMS nanocomposites has led to the development of an alternative route for improving mechanical strength of PDMS elastomers, conventionally known to have weak mechanical properties. The second study involves synthesis of a triblock copolymer comprising of four mutually immiscible phases, namely, soft segments comprising of fluorous and silicone domains, a diisocyanate hard segment and a glassy siliceous phase. Structure-property relationship has been established with an investigation of the interesting surface and bulk morphology. The highly improved mechanical strength of these soft materials is noteworthy. The dominance of silicone soft block at the triblock near surface has led to the third study which investigates their potential non-adhesive or abhesive characteristic in both a laboratory scale and in a marine environment. The peak removal stress and the removal energy associated with the detachment of a rigid object from the surface of these triblock copolymers have been measured. Results obtained from laboratory scale experiments have been verified by static immersion tests performed in the marine environment, involving the removal of adhered soft and hard fouling organisms. Gaining insights on the characteristics of an easy release surface, namely low surface energy and a low near surface modulus, a new way for controlling the near surface composition for elastomeric coatings have been developed. This technique involves an elastomer end-capped with a siliceous crosslinking agent and a tough, linear polyurethane. The basic concept behind the hybrid compositions is to develop a coating suitable for foul release applications, having a low energy surface, low surface modulus but good bulk mechanical strength. Henceforth, the fourth study deals with synthesis and characterization of the hybrid polymers over a wide range of composition and investigates their foul release characteristic in laborartory scale experiments. In our final study, attempts have been made in generating a silicone coating with antimicrobial property. A quaternary alkylammonium in different weight percents have been incorporated into a conventional, condensation cured polydimethylsiloxane (PDMS) elastomer. Antimicrobial assay has been performed on these modified silicone coatings to assess their biocidal activity against strains of Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. Surface accessibility of quaternary charges has been quantified by measuring the streaming potential of a modified coating. An effort has been made in improving the mechanical strength of the weak PDMS elastomers by adding treated fumed silica nanoparticles as reinforcements. The effect of adding fillers on the mechanical property (tensile), surface concentration of quaternary charge and on the biocidal activity of a representative sample has been investigated.
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25

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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26

Stewart, Shona Diane. "Surface enhanced Raman scattering on electrochemically prepared silver surfaces." Thesis, Queensland University of Technology, 1999.

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Yan, Liling. "Effects of surface topography on hydrophobicity of surfaces with spherical micro-protusions." Thesis, The University of Sydney, 2005. https://hdl.handle.net/2123/27892.

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The water repellency of a surface is principally governed by a combination of its chemical nature (i.e. surface energy) and topographical microstructure. The surface energy is an intrinsic property of a material that can be controlled by chemical modification, and other factors that can affect wettability, especially the surface topography were investigated. In particular, the study of topographical factors influencing the wettability of solid films is very important in View of production of surfaces with tailored properties and functions. The main objective of this research was to investigate the effect of surface topography on surface hydrophobicity. Particular emphasis was given to those surfaces with a particulate-like structure, which is one of the most popular surface features in natural and man-made superhydrophobic surfaces. Surfaces with particulate-like structure from both real superhydrophobic surface and model surfaces were characterized.
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Walton, Ryan J. "Characterization of Road Surfaces Using High Resolution 3D Surface Scans to Develop Parameters for Predicting Tire-Surface Friction." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1531432167496958.

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29

Vandadi, Aref. "Optimization of Superhydrophobic Surfaces to Maintain Continuous Dropwise Condensation." Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc500016/.

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In the past decade, the condensation on superhydrophobic surfaces has been investigated abundantly to achieve dropwise condensation. There is not a specific approach in choosing the size of the roughness of the superhydrophobic surfaces and it was mostly selected arbitrarily to investigate the behavior of condensates on these surfaces. In this research, we are optimizing the size of the roughness of the superhydrophobic surface in order to achieve dropwise condensation. By minimizing the resistances toward the transition of the tails of droplets from the cavities of the roughness to the top of the roughness, the size of the roughness is optimized. It is shown that by decreasing the size of the roughness of the superhydrophobic surface, the resistances toward the transition of the tails of droplets from Wenzel state to Cassie state decrease and consequently dropwise condensation becomes more likely.
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30

Andrews, Marilyn Mockus 1958. "Characterization of the surface acidity of passivated iron particles by flow microcalorimetry." Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/276614.

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The characteristics of passivated iron particles have been examined with flow microcalorimetry to determine the acidic nature of the surface sites. The molar heat of adsorption of pyridine from hexane was measured with a FMC and a differential refractive index detector, at 23 and 40°C. The adsorption data were found to obey the assumptions of the Freundlich isotherm. The adsorption densities at different temperatures were used to calculate the isosteric heat of adsorption. The molar heat of adsorption of triethylamine from hexane was also measured and combined with the data for pyridine in order to calculate the Drago constants for the iron particles. A static adsorption method was used for the adsorption of pyridine from hexane onto the iron particles, for comparison with the dynamic method. The heat of wetting for the iron particles, with hexane, has also been measured. The iron particles were examined with X-ray diffraction. Mossbauer spectroscopy, XPS, SEM, TEM, and electrophoresis to characterize the surface layer. These techniques have revealed that the iron particles are coated with ferric oxide and this surface is amphoteric in aqueous solutions.
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Murphy, Sherry M. "SURFACE." Digital Commons @ East Tennessee State University, 2013. https://dc.etsu.edu/etd/1152.

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This thesis paper supports the Master of Fine Arts exhibition at the Tipton Gallery, East Tennessee State University, from January 28th through February 8th, 2013. The exhibit is comprised of two hundred fifty-three porcelain objects and lines created with naturally colored porcelain slips used as paint. SURFACE presents my exploration of the natural world; the experiences and memories created during this process compelled this exhibition. Topics discussed are the influences, concepts, techniques, and methods used to create the work. Included are process images, detail images, and images of selected works from the exhibition.
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32

Poirier, Jason S. "Polymer Templating in Surfactant Monolayers." Fogler Library, University of Maine, 2004. http://www.library.umaine.edu/theses/pdf/PoirierJS2004.pdf.

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33

Kellogg, Diane Schneider. "Surface-enhanced Raman and electron spectroscopic investigations of lead-modified silver surfaces." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184862.

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Surface enhanced Raman scattering (SERS) is a powerful means for obtaining vibrational data from the metal/electrolyte or metal/gas interfacial environment. However, SERS is only observed for a limited number of metal surfaces under certain experimental conditions. Before this method can become a universal tool, the enhancement mechanism(s) must be understood. The results reported in this dissertation assess both electronic and chemical contributions to the SERS mechanism. The electronic properties of the metal are altered by systematic deposition of Pb or Cu onto a substrate that supports intense SERS, Ag. The chemical nature of the interface is altered with different probe molecules. The effect of Pb deposition on the SERS enhancing ability of Ag electrodes has previously been investigated with strongly adsorbed probe molecules. The behavior of cyanide species in the presence of Pb⁺² is complicated by the necessity of maintaining low solution pH to prevent Pb(OH)₂ precipitation; thus, the predominant solution species is HCN. Although previous reports state that no SERS can be detected from cyanide-containing solutions below pH 6, intense SERS signals can be obtained at pH 2 if sufficiently positive electrode potentials are maintained. The two unresolved SERS bands observed in acidic solutions are attributed to HCN which interacts with the Ag surface in end-on and side-on configurations. The predominant effect of Pb deposition on HCN SERS is HCN displacement. Enhancement due to charge transfer processes is not significant, while electromagnetic effects dictate the residual SERS intensity remaining after the initial HCN displacement. The supporting electrolyte anion affects the rate of change of the potential dependent C≡N stretch in basic CN⁻ media. A correlation between the rate of frequency change and anion charge/radius ratio was observed at potentials near and slightly negative of the Ag potential of zero charge in basic CN⁻ media. These results demonstrate the extraordinary sensitivity of SERS to interfacial conditions. The contributions from chemical and electromagnetic enhancement are further assessed by following excitation wavelength dependence of the SERS intensity of pyridine and Cl⁻ as a function of Cu coverage. Contributions from both are observed, but chemical enhancement is less evident for Cu than for Pb deposition. This is related to the smaller change in work function that occurs as a consequence of Cu versus Pb deposition on Ag surfaces.
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Bradley, Matthew K. "Density functional theory investigations of surface structure and surface stress in adsorbate layers on Cu, Pd and Ir surfaces." Thesis, University of Warwick, 2012. http://wrap.warwick.ac.uk/51619/.

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An introduction to surface structure and plane wave density functional theory (DFT) is presented along with theoretical studies of seven adsorbate systems. A new energetically favourable structure of low symmetry is found for furan on Pd(111) that is entirely consistent with previous experimental findings from scanned-energy mode photoelectron diffraction (PhD). In addition, it is found that the C3H3 decomposition product of furan on the same surface is likely to be adsorbed in a propargyle conformation (CH-C-CH2) although some cooccupation of the molecule in a half benzene conformation (CH-CH-CH) is also possible. Methoxy is found to adsorb at local short bridge sites only on Cu(110), occupying locations both above the clean surface and above pairs of surface Cu adatoms. Simulated scanning tunneling microscope (STM) images of the (5×2) reconstruction are found to be in qualitative agreement with previous images recorded experimentally. The experimentally determined local structure of cytosine on the same surface is confirmed and models are proposed for the (6×6) reconstruction. An increased tensile surface stress is found to be associated with the Ir(001)(1×1) ! Ir(001)(5×1)-hex phase transition, thus confirming that the reconstruction is not a consequence of the large surface stress of bulk terminated Ir(001). In contrast, H adsorption on Ir(001) (5×1)-hex does lead to a reduction of the surface stress in the range 1.76-2.06 Nm−1 for a H coverage range 0.6-0.8 ML in excellent agreement with the experimentally-determined value of 1.7 Nm−1. The energetically favourable structure for methanethiolate adsorption on Cu(100) is found to be a c(6×2) missing row structure that allows effective relief of surface stress. On Cu(111) several complex overlayer models for methanethiolate adsorption have similar associated surface energy, suggesting that the local structure is dependent on the availability of Cu adatoms. For adsorption on both surfaces, agreement with previous STM images and MEIS results is discussed.
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35

Ignatiev, Pavel. "Theoretical study of spin-polarized surface states on metal surfaces." kostenfrei, 2009. http://nbn-resolving.de/urn:nbn:de:gbv:3:4-688.

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36

Hakim, Ali. "Characterization of Hard Metal Surfaces after Various Surface Process Treatments." Thesis, Linköping University, The Department of Physics, Chemistry and Biology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-12433.

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The aim of this thesis is to investigate how material surfaces are affected by various surface treatments and how this relates to the adhesion of the coating. The materials that were studied were WC-Co and Cermets and the surface treatments used were polishing, grinding with coarser and finer abrasive grains, and finally wet blasting and dry blasting. Focus was on deformations and residual stresses in the surface, surface roughness and cracks. The test methods used for examining the samples included surface roughness measurements, residual stress measurements, adhesion tests using Rockwell indentation and SEM images of the surface and the cross section.

The results concluded that polishing gives very good adhesion. Additionally, the adhesion for ground surfaces was good for WC-Co but very poor for Cermets. Furthermore, it was observed that finer abrasive grains did not result in better adhesion. In fact, the coarser grains gave slightly better results. Finally, it was concluded that wet blasting has a clear advantage over dry blasting and results in much better adhesion, especially for the Cermets. The results for the WC-Co were a bit inconsistent and so further research is required.

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37

Ramsvik, Trond. "Surface science studies of Cobalt and Rhodium single crystal surfaces." Doctoral thesis, Norwegian University of Science and Technology, Department of Physics, 2001. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-2000.

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The main topic of this thesis is the investigation of small molecules adsorbed on the transition metals cobalt and rhodium surfaces by means of predominantly high-resolution core level photoemission and near edge x-ray absorption fine structure (NEXAFS). The thesis can be divided into three parts where the following phenomena are examined:

1) internal molecular vibrations in the core level photoemission spectra

2) hybridisation and thermal decomposition of adsorbates

3) growth and surface alloy formation of metal-on-metal systems

The influence on the C 1s spectra of photoemission induced internal vibrations after chemisorption is presented for two molecules, acetylene (C2H2) and carbonmonoxide (CO). In the former case the fine structure of the C-H vibrational stretch mode of acetylene on Co(0001) single crystal surface is resolved. The measured vibrational energy splitting is (389 ± 8) meV, which is ~6 % lower than what has been reported for gaseous acetylene. The corresponding Sfactor of 0.17 ± 0.02 is considerably higher than those reported for other systems. For CO molecules adsorbed on metal surfaces the C-O stretch vibration has a vibrational energy which is about half that of the C-H stretch in hydrocarbons. The progression of this vibrational mode for the systems CO/Co(0001), CO/Rh(100) and CO/Rh(111) have been thoroughly investigated. CO adsorbs in on-top sites on Co(0001) resulting in a vibrational splitting of (210 ± 3) meV from the adiabatic C 1s peak. For CO on Rh(100) two adsorption sites, on-top and bridge, are populated. Similar analyses of the vibrational fine structure gives a vibrational splitting of (221 ± 4) meV for on-top site and (174 ± 11) meV for bridge site. Investigations of the C-O vibrational properties on Rh(111), where CO populates on-top and three-fold hollow sites, show the same trend as for CO on Rh(100), namely decreasing vibrational splitting with increasing co-ordination. A tendency of increasing S-factor with increasing co-ordination is also reported.

Acetylene hybridisation and thermal decomposition on two crystal orientation of cobalt, Co(0001) and Co(1120) , have been investigated using a variety of experimental techniques: NEXAFS shows that acetylene chemisorb strongly to both cobalt surfaces. For the system C2H2/Co(0001) a state of hybridisation close to sp3 has been deduced, which is considerably stronger than what has been reported earlier. Photoemission spectroscopy measurements show that acetylene starts to decompose at a temperature ~100 K lower for Co(1120) compared to Co(0001). For the anisotropic Co(1120) surface the acetylene decomposition lead to formation of an ordered carbon overlayer. By combining these results with STM and LEED measurements a hard sphere model has been proposed for this overlayer.

Rare earth metals induce solid state reactions when thin overlayers are deposited onto a variety of metals and followed by annealing. Using high-resolution photoemission spectroscopy, LEED and temperature programmed desorption (TPD) a true surface alloy is shown to form with new electronic states when La on Rh(100) is annealed to 1350 K. These states alter the hybridisation of CO significantly compared to clean Rh(100) and as-deposited La on Rh(100). TPD experiments show CO desorption peaks at significantly lower temperature than CO on the as-deposited La/Rh(100), but still higher than the desorption peaks found for CO on Rh(100).

The homoepitaxial growth of cobalt on Co(1120) has been studied by STM. The diffusion of Co adatoms is found to be highly anisotropic with larger mobility of added Co atoms parallel than perpendicular to [0001], i.e. along the zigzag rows of the unreconstructed Co(1120) surface.


Papers are reprinted with kind permission of Elsevier, sciencedirect.com
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38

Berry, Elizabeth. "Fabrication of multiscale random rough surfaces with prescribed surface statistics." Thesis, Imperial College London, 1986. http://hdl.handle.net/10044/1/37944.

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39

Hao, Shuai. "An Introduction to Discrete Minimal Surfaces via the Enneper Surface." Thesis, Southern Illinois University at Edwardsville, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1543912.

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In this paper, we are exploring how to construct a discrete minimal surface. We map the conformal curvature lines of a parameterized continuous minimal surface to a unit sphere by the Gauss map. Then, based on a circle patterns we create, the Koebe polyhedron can be obtained. By dualizing the Koebe polyhedron, we are able to get the discrete minimal surface. Moreover, instead of only developing the method theoretically, we also show concrete procedures visually by Mathematica for Enneper with arbitrary domain. This is an expository project mainly based on the paper "Minimal surface from circle patterns: geometry from combinatorics" by Alexander I. Bobenko, Tim Hoffmann and Boris A. Springborn.

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40

Sharkey, Sarah Jane. "Laser surface engineering and process control for wear resistant surfaces." Thesis, University of Liverpool, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321167.

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41

Myshlyavtsev, Alexander V., and Marta D. Myshlyavtseva. "Modeling of surface diffusion for stepped surfaces: transfer matrix approach." Diffusion fundamentals 6 (2007) 27, S. 1-2, 2007. https://ul.qucosa.de/id/qucosa%3A14201.

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42

Thompson, Wade Raymond. "Surface Raman scattering of organically-modified metal and oxide surfaces." Diss., The University of Arizona, 1994. http://hdl.handle.net/10150/186773.

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This research project was designed to investigate the surface chemistry of organosilanes at metal and oxide surfaces, specifically Ag, Au, SiO₂, and Al₂O₃. A combination of surface Raman spectroscopy, electrochemistry, scanning electron microscopy, x-ray photoelectron spectroscopy, and ellipsometry have been employed to study several important aspects of these films. Tetramethoxysilane (TMOS) and 1-propanethiol are used as models to provide detailed vibrational assignments for (3-mercaptopropyl)trimethoxysilane (3MPT). The vibrational assignments for 3MPT are used to assess the conformational order of 3MPT monolayers at Ag and Au surfaces before and after hydrolysis and condensation. Particular emphasis is given to the ν(Si-O), ν(C-H) modes, and the trans and gauche ν(C-S), ν(Si-C), and ν(C-C) modes in the frequency regions between ca. 500 to 1300 cm⁻¹ and ca. 2700 to 3000 cm⁻¹. The reactivity of the residual surface silanols and the wetting properties of the hydrolyzed 3MPT result in the surface acting as a modifying agent for the attachment of thin dielectric layers such as SiO₂ on Ag and Au surfaces. Adhesion of the thin SiO₂ films to the metal surfaces are characterized using standard qualitative and quantitative adhesion tests. Raman spectra of molecular assemblies of octadecylsilane layers, a model of reversed-phase liquid chromatographic stationary phase materials, are acquired using a thin silica gel/3MPT/Ag sandwich structure as the substrate. The Ag surface provides electromagnetic enhancement to the octadecylsilane overlayer. Spin coating a silica sol on the modified Ag surface results in the formation of a thin silica gel layer which contributes minimal fluorescence background to the Raman spectra. The spectra are interpreted in terms of the alkyl chain conformation on dry silica surfaces as well as in the presence of solvents commonly used in chromatography. The feasibility of acquiring Raman data from an Al/Al₂O₃ surface without an enhancing adlayer is demonstrated. Self-assembled films of octadecylsilane, octadecyldimethylsilane, and stearic acid were evaluated by Raman spectroscopy in terms of alkyl chain conformation. These data represent the first Raman spectra reported for alkylsilane layers on silica and Al₂O₃ surfaces without an enhancing adlayer and demonstrate the feasibility of acquiring conformational information from alkyl chains bound to oxide surfaces.
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43

Winsby, Andrew James. "Direct surface generation and surface orientated control." Thesis, Lancaster University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.413812.

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44

Mukundan, Harish. "Surface-surface intersection with validated error bounds." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33167.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 97-100).
This thesis presents a robust method for tracing intersection curve segments between continuous rational parametric surfaces, typically rational polynomial parametric surface patches. Using a validated ordinary differential equation (ODE) system solver based on interval arithmetic, we obtain a continuous, validated upper bound for the intersection curve segment in the parametric space of each surface. Application of the validated ODE solver in the context of eliminating the pathological phenomena of straying and looping is discussed. We develop a method to achieve a continuous gap-free boundary with a definite numerically verified upper bound for the intersection curve error in parameter space. This bound in parametric space is further mapped to an upper bound for the intersection curve error in 3D model space, denoted as model space error, which assists in defining robust boundary representation models of complex three-dimensional solids. In addition, we also discuss a method for controlling this model space error so that it takes values below a predefined threshold (tolerance). Application of the above method to various examples is further demonstrated.
by Harish Mukundan.
S.M.
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45

Thorsness, Adam G. "Surface Pretreatment for Thin Film Surface Reactivity." Diss., The University of Arizona, 2006. http://hdl.handle.net/10150/194965.

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The formation of a self-limiting interface layer for the integration of high-k dielectric materials into silicon based transistor devices was investigated. Chlorine atoms were used to activate a liquid cleaned Si(100) surface for the reaction with H₂O(g). A saturation coverage of 0.8 monolayers of chlorine atoms was deposited on a hydrogen terminated Si(100) surface by exposure to Cl₂ gas at 10 Torr under ultraviolet illumination at 300 K. The self-limiting interface layer was formed by exposing the chlorine terminated surface to water vapor at P(HOH)=100 Torr and temperatures ranging from 325 to 373 K. The coverage of oxygen resulting from H₂O exposures was directly correlated with a decrease in the Cl coverage and ranged from 0.2-1.2 monolayers. Complete removal of surface chlorine was achieved by 100°C water exposures in 45 minutes. The final chapter summarizes three papers published which describe the moisture absorption into borophosphosilicate glass (BPSG) films and an investigation of a gas phase etching process applied to borosilicate glass (BSG), phosphosilicate glass (PSG), and BPSG films. The absorption and reaction of water with doped and undoped oxides as well as the effect of annealing was investigated using a variety of annealed BPSG films. Asdeposited (AD) and annealed (500, 750, and 900°C) borophosphosilicate glass (BPSG) films were characterized during aging, baking, and etching using transmission Fourier transform infrared spectroscopy and ellipsometry. The water content in the BPSG films increased steadily during storage at ambient conditions. The B-O bond was shown to be the primary site for water adsorption on the surface of the film. Water absorption into the film was consistent with a reaction-limited model. It is likely that the water present reacted readily with P=O groups forming P-O and PO-H. This slower reaction with P=O species is proposed as the rate-limiting step for water absorption. The etching of BPSG with gas phase HF produced a low volatility residue consisting of a mixture of boric acid B(OH)₃, phosphoric acid H₃PO₄, and water. Partial removal of the residue was accomplished using both direct and indirect UV–Cl₂ processes.
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46

Hansson, Petra M. "Hydrophobic surfaces: Effect of surface structure on wetting and interaction forces." Doctoral thesis, KTH, Yt- och korrosionsvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-103409.

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The use of hydrophobic surfaces is important for many processes both in nature and industry. Interactions between hydrophobic species play a key role in industrial applications such as water-cleaning procedures and pitch control during papermaking but they also give information on how to design surfaces like hydrophobic mineral pigments. In this thesis, the influence of surface properties on wetting and interaction forces has been studied. Surfaces with close-packed particles, pore arrays, randomly deposited nanoparticles as well as reference surfaces were prepared. The atomic force microscope (AFM) was utilized for force and friction measurements while contact angles and confocal Raman microscopy experiments were mainly used for wetting studies. The deposition of silica particles in the size range of nano- to micrometers using the Langmuir-Blodgett (LB) technique resulted in particle coated surfaces exhibiting hexagonal close-packing and close to Wenzel state wetting after hydrophobization. Force measurements displayed long-range interaction forces assigned to be a consequence of air cavitation. Smaller roughness features provided larger forces and interaction distances interpreted as being due to fewer restrictions of capillary growth. Friction measurements proved both the surface structure and chemistry to be important for the observed forces. On hydrophobic pore array surfaces, the three-phase contact line of water droplets avoided the pores which created a jagged interface. The influence of the pores was evident in the force curves, both in terms of the shape, in which the three-phase contact line movements around the pores could be detected, as well as the depth of the pores providing different access and amount of air. When water/ethanol mixtures were used, the interactions were concluded to be due to ethanol condensation. Confocal Raman microscopy experiments with water and water/ethanol mixtures on superhydrophobic surfaces gave evidence for water depletion and ethanol/air accumulation close to the surface. Force measurements using superhydrophobic surfaces showed extremely long-range interaction distances. This work has provided evidence for air cavitation between hydrophobic surfaces in aqueous solution. It was also shown that the range and magnitude of interaction forces could, to some extent, be predicted by looking at certain surface features like structure,roughness and the overall length scales.

QC 20121011

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47

Jalisse, Ilyes. "Capteur Interférométrique de Contraintes de Surface." Electronic Thesis or Diss., Bordeaux, 2025. http://www.theses.fr/2025BORD0007.

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Les parois déformables jouent un rôle essentiel dans de nombreux systèmes d’intérêt, notamment dans le domaine biologique. Pour comprendre les propriétés de surface des gels, telles que le mouillage ou l’adhérence, il est crucial de tenir compte des déformations à longue portée. Les articulations synoviales, par exemple, présentent des propriétés de lubrification remarquables. Cependant, les mécanismes sous-jacents à cette performance, qui impliquent des macromolécules chargées et des parois souples, restent encore mal compris. Dans ce contexte, nous avons développé un capteur de contrainte de surface basé sur un appareil à force de surfaces (SFA), permettant de mesurer avec précision les déformations d’une membrane élastique grâce à l’interférence à faisceaux multiples. Les membranes utilisées sont produites à l’aide d’une méthode robuste et sont caractérisées par des tests d’actionnement électrostatique et des essais de gonflement. Dans un premier temps, nous avons analysé la réponse statique des membranes sous actionnement électrostatique. Les forces mises en jeu ont démontré la capacité de notre dispositif à mesurer des forces d’interaction de l’ordre du μN. Par la suite, nous avons étudié les interactions sphère-membrane en présence d’électrolytes, sous l’application d’un champ électrique alternatif. Les résultats ont révélé l’apparition d’une force d’attraction en raison de la réduction de l’écrantage du champ électrique, et d’une force de répulsion osmotique, observable à long terme. Enfin, nous avons exploré le couplage élastohydrodynamique (EHD), qui se manifeste lorsqu’un objet solide se déplace à proximité d’une membrane élastique en milieu aqueux. Ces travaux ouvrent des perspectives pour mieux comprendre les interactions entre des surfaces souples déformables et leur environnement
Compliant surfaces play a crucial role in many systems of interest, particularly in the biological domain. To understand the surface properties of gels, such as wettability or adhesion, it is essential to account for long-range deformations. Synovial joints, for instance, exhibit remarkable lubrication properties. However, the mechanisms underlying this performance, which involve charged macromolecules and soft surfaces, remain poorly understood. In this context, we developed a surface stress sensor based on a surface forces apparatus (SFA), enabling precise measurement of the deformation of an elastic membrane through multiple beam interferometry. The membranes used are produced using a robust method and are characterized through electrostatic actuation tests and swelling experiments. First, we analyzed the static response of the membranes under electrostatic actuation. The forces involved demonstrated the capability of our device to measure interaction forces on the order of μN. Subsequently, we studied spheremembrane interactions in the presence of electrolytes under the application of an alternating electric field. The results revealed the emergence of an attractive force due to the limited electrostatic screening, and a repulsive osmotic force, observable over the long term. Finally, we explored the elastohydrodynamic (EHD) coupling that arises when a solid object moves near an elastic membrane in an aqueous environment. These studies open new perspectives for understanding interactions between soft, deformable surfaces and their surroundings
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48

Feng, Yongjia. "First principles studies of transition metal surfaces : the effect of an external field on surface electronic properties and surface energetics /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?PHYS%202003%20FENG.

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Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2003.
Includes bibliographical references (leaves 106-110). Also available in electronic version. Access restricted to campus users.
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49

Rulence-Pâques, Patricia. "Perception de surface et inférence de surface : le cas de la surface du rectangle." Paris 5, 1996. http://www.theses.fr/1996PA05A003.

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50

Pauchet, Sylvain. "From surface to surface - Transformations de surface tactile pour l’interaction incarnée dans le cockpit." Thesis, Toulouse, ISAE, 2019. http://www.theses.fr/2019ESAE0018/document.

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Abstract:
La « surface », dans les systèmes interactifs tactiles est à la fois le support du toucher et de l’image. Alors qu’au fil du temps les surfaces tactiles se sont transformées dans leur épaisseur, forme et rigidité, la modalité d’interaction se limite, comme sur les premiers dispositifs, à une mise en contact simple du doigt avec l’écran dans un geste qui feint de manipuler ce qui est affiché. Le sens du toucher, même pour des dispositifs tactiles installés dans des systèmes critiques comme dans l’aéronautique ou l’automobile, reste essentiellement sollicité en tant que prolongement de la vision, pour pointer et contrôler. Alors que les théories de la phénoménologie de la perception, de la perception écologique et des interactions tangibles et incarnées reconnaissent l’importance du corps, de la motricité et des interactions avec l’environnement dans les phénomènes perceptifs, il paraît réducteur de continuer à considérer la vision comme sens premier et principal de l’interaction tactile.Nous pensons que la transformation de la forme physique de l’interface tactile est un moyen efficace pour réincarner l’espace d’interaction tactile en utilisant mieux les capacités motrices des utilisateurs ainsi que leurs habiletés à négocier, manipuler et s’orienter dans leur environnement. A partir d’une caractérisation des risques potentiels du développement des interactions tactiles dans le contexte d’un cockpit d’avion de ligne (augmentation de la charge cognitive, sur-sollicitation du canal visuel, altération de la conscience de la situation, etc.), nous explorons les apports d’une interface tactile à changement de forme pour améliorer la collaboration pilotes-système au travers de la conception, la fabrication et l’évaluation de trois prototypes fonctionnels. Avec l’étude qualitative et quantitative du prototype GazeForm, nous montrons que le changement de forme d’une surface tactile en fonction de la position du regard permet de diminuer la charge de travail, améliorer la performance, réduire les mouvements oculaires et améliorer la distribution de l’attention visuelle comparativement à un écran tactile classique. Par l’élaboration du concept Multi-plié nous mettons en évidence les dimensions et propriétés de la transformation par pliure d’une surface d’affichage interactive. Avec les évaluations qualitatives des deux dispositifs illustrant le concept, le premier présentant une série d’écrans tactiles articulés et le deuxième une surface d'affichage tactile « plissable », nous démontrons qu’une surface tactile continue pliable offre un support pertinent à l'interaction incarnée et permet d’augmenter la sensation de contrôle pour la gestion d’un système critique. Enfin, pour généraliser la connaissance produite à d’autres contextes d’usages avec une forte division de l’attention visuelle (conduite automobile, salle de contrôle, appareil tactile portable en mobilité) nous proposons un espace de conception pour les interfaces tactiles reconfigurables
The "surface" in interactive touch systems is both the support of touch and image. While over time touch surfaces have been transformed in their thicknesses, shapes and stiffness, the interaction modality is limited, as on the first devices, to a simple contact of the finger with the screen in a gesture that pretends to manipulate what is displayed. The sense of touch, even for touch devices installed in critical systems, such as in the aeronautics or automotive industries, remains mainly used as an extension of vision, to point and control. While the theories of the phenomenology of perception, ecological perception and tangible and embodied interactions recognize the importance of the body, motor skills and interactions with the environment in perceptual phenomena, it seems simplistic to consider vision as the first and main sense of touch interaction. We believe that transforming the physical form of the touch interface is an effective way to reincarnate the space of touch interaction by making better use of users' motor skills and their ability to negotiate, manipulate and orient themselves in their environment. Based on a characterization of the potential risks of developing touch interactions in the context of an airliner cockpit (increase in cognitive load, overload of the visual channel, alteration of situational awareness, etc.), we explore, through the design, manufacture and evaluation of three functional prototypes, the contributions of a touch interface with shape change to improve pilotes-system collaboration. With the qualitative and quantitative study of the GazeForm prototype, we show that changing the shape of a touch surface according to the position of the gaze makes it possible, compared to a conventional touch screen, to reduce the workload, improve performance, reduce eye movements and improve the distribution of visual attention. By qualitative evaluation of the two Multi-plié devices, the first with a series of articulated touch screens and the second with a "pleatable" touch display surface, we show that a transformable touch surface stabilizes touch action, promotes collaboration and improves situational awareness. In addition to these contributions, we find that changing the shape of the touch interaction surface increases the feeling and level of control for the management of a critical system. Finally, to generalize the knowledge produced to other contexts of use with a strong division of visual attention (driving, control room, portable touch device in mobility) we propose a design space for reconfigurable touch interfaces
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