Rozprawy doktorskie: „Surface properties of materials”

1

Shah, Amit. "Surface reproducibility of impression materials". Thesis, Birmingham, Ala. : University of Alabama at Birmingham, 2007. http://www.mhsl.uab.edu/dt/2007m/shah.pdf.

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Nayakasinghe, Mindika Tilan Abeyrathna. "Fundamental Surface Properties and Gas-Surface Interactions of Two-Dimensional Materials". Diss., North Dakota State University, 2019. https://hdl.handle.net/10365/29325.

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Heterogeneous model catalysis with supported nanomaterials on ultra-thin two-dimensional films has contributed significantly to improve the existing industrial catalytic processes, as well as to discover novel ways to enhance selectivity, specificity, and stability of the catalysts. Silica and zeolites are of particular interest, which has been widely utilized as catalysts and catalytic supports in several industrial processes. However, there are a limited number of surface science studies with zeolites due to the lack of surface analogs. Understanding the fundamental surface properties of silica and zeolites, involving the synthesis of surface analogs of silica and zeolites, characterization, surface modification, and screening for chemical and physical properties connected to the heterogeneous catalysis related applications utilizing advanced ultra-high vacuum-based surface science techniques is the main focus of this dissertation. Catalyst particles should be finely distributed on high surface area supports, in order to have high selectivity and specificity. Particle agglomeration during extreme catalyst operation (reaction) conditions decreases the efficiency of the catalysts over time. One common strategy to address the issue of particle agglomeration is to promote strong catalyst-support interactions. In this study, chemical reactivity of the inert silica was improved by doping with aluminum, which enhanced the polarity of silica (2D-zeolites) and hence the catalyst-support interactions compared to inert silica. Organohalide perovskite thin films are a fascinating class of material, which attract much attention in the recent past as the light harvesting materials in solar cells due to excellent power conversion efficiencies. However, poor thermal, chemical, and long-term stability limit the industrial applications of these organohalide perovskites. Gas-surface interactions on methylammonium lead iodide perovskite thin films were investigated in order to understand the thermal and the chemical degradation mechanisms utilizing UHV-based surface analytical techniques combined with computational calculations. Thermal stability improvement of the perovskite thin films by surface passivation using a protective chemical inhibition layer was successfully investigated experimentally.
ACS-PRF
North Dakota State University. Department of Chemistry and Biochemistry
North Dakota State University. Research and Creative Activity

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3

Li, Shuangwu. "Surface properties of electrospun polymer nanofibres". Thesis, Queen Mary, University of London, 2010. http://qmro.qmul.ac.uk/xmlui/handle/123456789/548.

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Fibrous materials are used in a variety of applications due to their relatively high surface area to volume ratio as well as anisotropic behaviour. Electrospinning is a popular fabrication technique which produces polymer nanofibres with a potentially high molecular orientation. The surface of polymer fibres plays a significant role in many applications thus measurement of their surface properties is essential but challenging due to their relatively small size. In this thesis, ultrafine nanofibres have been produced by electrospinning with their nanofibre morphology controlled by varying different processing parameters. Atomic force microscopy (AFM) adhesion contact mechanics and individual nanofibre wetting measurements have been conducted to explore surface properties of the produced electrospun polymer fibres. Results using traditional Owens-Wendt plots applied to our nanomaterials show electrospun nanofibres have a higher dispersive surface free energy compared to bulk polymer film but a lower polar contribution, giving a total surface free energy in excess of bulk equivalents. A novel proposed model indicates that this nanofibre dispersive surface free energy is intimately linked to density of the polymer and ultimately the molecular spacing or orientation for the polymer chains. Comparisons are made with bulk polymer films to show that a high degree of molecular orientation is present at least at the surface of the polymer nanofibre. Structure investigations on electrospun fibres of polyvinyl alcohol using FTIR and XPS surface techniques explore how an increase in hydrogen bonds formed within nanofibres rather than on the fibre surface enhance this dispersive contribution but lowers the polar contribution. The wetting behaviour of electrospun fibre is extended to assemblies at length scales above individual fibres to highlight how superhydrophobic surfaces can be produced from nanofibre networks with defined spacings and geometries. This superhydrophobicity was adequately described by a Cassie-Baxter model modified to account for the fibrous geometry.

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4

Chang, Wai-Kit. "Porous silicon surface passivation and optical properties". Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/41426.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1996.
"June 1996."
Includes bibliographical references (leaves 84-85).
by Wai-Kit Chang.
S.M.

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5

Ojo, Sonia. "Simulation Studies of surface and bulk properties of materials". Thesis, University College London (University of London), 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.396360.

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6

Nelson, Geoffrey Winston. "Surface characterization and functional properties of carbon-based materials". Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:f22b95ce-65f3-4d9e-ac3d-a88f6e142c1a.

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Carbon-based materials are poised to be an important class of 21st century materials, for bio-medical, bio-electronic, and bio-sensing applications. Diamond and polymers are two examples of carbon-based materials of high interest to the bio-materials community. Diamond, in its conductive form, can be used as an electrochemical bio-sensor, whilst its nanoparticle form is considered a non-inflammatory platform to deliver drugs or to grow neuronal cells. Polymers, especially when chemically modified, have been used extensively in biological environments, from anti-microbial use to drug delivery. The large-scale use of either material for biological use is limited by two factors: ease of chemical modification and the paucity of knowledge of their surface chemistry in aqueous media. This thesis addresses aspects of both these issues. The first study reported is an in situ study of the adsorption dynamics of an exemplar globular protein (bovine serum albumin, BSA) on nanodiamond using the relatively novel quartz crystal microbalance with dissipation (QCM-D) technique. For the first time, QCM-D enabled the detailed study of protein dynamics (i.e. kinetics, viscoelastic properties, overlayer structure, etc.) onto nanodiamond thin films having various surface chemistry and roughness. The dynamics of protein adsorption is found to be sensitive to surface chemistry at all stages of adsorption, but it is only sensitive to surface roughness during initial adsorption phases. Our understanding of the nanodiamond-biology interface is enhanced by this study, and it suggests that QCM-D is useful for the study of the surface chemistry of nanoparticle forms of inorganic materials. A second study concerns a novel surface functionalization scheme, based on carbene and azo-coupling chemistry, which has been recently introduced as a practical, facile method for modifying the surfaces of polymers. Using modern surface characterization techniques, it is demonstrated that a chemical linker can be attached to polystyrene surfaces using carbene-based chemistry, and that further chemical functionality can be added to this chemical linker via an azo-coupling reaction. In situ studies of protein dynamics at these interfaces were conducted using QCM-D, thus enabling a link between specific protein behaviour and the polymer surface chemical termination chemistry to be made. A third area of study of investigates the use of diamond electrodes as a bio-sensor for dopamine under physiological conditions. For these conditions, ascorbic acid interferes with the dopamine oxidation signal, in ways that render the two signals irresolvable. Various modifications are used in attempts to reduce this interference, including: small and large cathodic treatments, grafting of electro-active polymers, addition of carbon nanotubes, and hydrogen plasma treatment. Those modifications leading to the hydrogen-termination of diamond are shown to work the best. Notably, hydrogen plasma treatment effects the complete electrochemical separation of dopamine and ascorbic acid at a diamond electrode. This is the first time this has been accomplished without adding non-diamond materials to the diamond electrode surface.

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7

Karlsson, Linda. "Transmission Electron Microscopy of 2D Materials : Structure and Surface Properties". Doctoral thesis, Linköpings universitet, Tunnfilmsfysik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-127526.

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During recent years, new types of materials have been discovered with unique properties. One family of such materials are two-dimensional materials, which include graphene and MXene. These materials are stronger, more flexible, and have higher conductivity than other materials. As such they are highly interesting for new applications, e.g. specialized in vivo drug delivery systems, hydrogen storage, or as replacements of common materials in e.g. batteries, bulletproof clothing, and sensors. The list of potential applications is long for these new materials. As these materials are almost entirely made up of surfaces, their properties are strongly influenced by interaction between their surfaces, as well as with molecules or adatoms attached to the surfaces (surface groups). This interaction can change the materials and their properties, and it is therefore imperative to understand the underlying mechanisms. Surface groups on two-dimensional materials can be studied by Transmission Electron Microscopy (TEM), where high energy electrons are transmitted through a sample and the resulting image is recorded. However, the high energy needed to get enough resolution to observe single atoms damages the sample and limits the type of materials which can be analyzed. Lowering the electron energy decreases the damage, but the image resolution at such conditions is severely limited by inherent imperfections (aberrations) in the TEM. During the last years, new TEM models have been developed which employ a low acceleration voltage together with aberration correction, enabling imaging at the atomic scale without damaging the samples. These aberration-corrected TEMs are important tools in understanding the structure and chemistry of two-dimensional materials. In this thesis the two-dimensional materials graphene and Ti3C2Tx MXene have been investigated by low-voltage, aberration-corrected (scanning) TEM. High temperature annealing of graphene covered by residues from the synthesis is studied, as well as the structure and surface groups on single and double Ti3C2Tx MXene. These results are important contributions to the understanding of this class of materials and how their properties can be controlled.

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8

Meyer, Anne E. "Dynamics of "conditioning" film formation on biomaterials". Malmö : [s.n.], 1990. http://catalog.hathitrust.org/api/volumes/oclc/21989234.html.

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9

Klein, Katherine. "Electromagnetic properties of high specific surface minerals". Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/20699.

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10

Murphy, Matthew. "Evaluation of dental implant materials and interactions with calcium phosphate solutions". Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/evaluation-of-dental-implant-materials-and-interactions-with-calcium-phosphate-solutions(62aff83f-146d-4c79-85fd-0fb95c4d31e2).html.

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In this thesis, four experimental studies are reported. Two concern the surface structure of commercially relevant dental implant materials. Characterisation of four treated substrates supplied by Straumann AG was carried out. These include substrates equivalent to the commercially available SLA, SLActive and Roxolid implants. The materials vary in substrate alloy, commercially pure (grade 2) Ti and a TiZr alloy, and surface preparation treatments. All substrates are sandblasted and acid etched however post-etching one set are stored in air whilst the others are stored in saline. Within the work both substrate composition and surface treatment is shown to impact on the respective surface oxide thickness, crystallinity and morphology. The other two experimental studies concern calcium phosphate deposition from solution onto substrates. The first investigation is the deposition of calcium phosphate from a simulated body fluid onto implant-like substrates, shown to be structurally equivalent to the SLA and SLActive implant surfaces. The effect of surface modifications on calcium phosphate deposition is investigated; over the period investigated calcium phosphate did not deposit onto the SLA substrate, whilst deposition occurred within 3 days on the SLActive substrate. The role of Mg2+ ions in the simulated body fluid is also investigated, with increased [Mg2+] resulting in a longer induction period and modified crystallinity of the hydroxyapatite film formed. The final study is a model study of the initial calcium phosphate deposition on to substrates. TiO2 rutile (110) and Al2O3 corundum (0001) were prepared to be atomically flat and then exposed to a simple calcium phosphate solution. Changes in surface structure and surface chemistry over the first three hours of exposure were investigated. Deposition occurred rapidly on both substrates with a complete surface coverage after 3 hours.

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11

Wells, Andrea Dawn. "Deposition, surface chemistry, and electrochemistry of YBa₂Cu₃O₇₋(subscript delta) materials". Access restricted to users with UT Austin EID, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3036611.

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12

Hou, Xiaoning. "Surface Topographies and Mechanical Properties of Metallic Biomaterials Processed by Ultrasonic Nanocrystal Surface Modification (UNSM)". University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1555602578757154.

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13

Freij-Larsson, Christina. "Surface modification of biomedical polyurethanes". Lund : Dept. of Chemical Engineering II, Lund University, 1996. http://catalog.hathitrust.org/api/volumes/oclc/38985470.html.

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14

Lawson, Hunter B. "A Novel Method for the Examination of the Surface Properties of Tungsten". Ohio University Honors Tutorial College / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1524839026783661.

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15

Plachinda, Pavel. "Electronic Properties and Structure of Functionalized Graphene". PDXScholar, 2012. https://pdxscholar.library.pdx.edu/open_access_etds/585.

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The trend over the last 50 years of down-scaling the silicon transistor to achieve faster computations has led to doubling of the number of transistors and computation speed over about every two years. However, this trend cannot be maintained due to the fundamental limitations of silicon as the main material for the semiconducting industry. Therefore, there is an active search for exploration of alternate materials. Among the possible candidates that can may [sic] be able to replace silicon is graphene which has recently gained the most attention. Unique properties of graphene include exceedingly high carrier mobility, tunable band gap, huge optical density of a monolayer, anomalous quantum Hall effect, and many others. To be suitable for microelectronic applications the material should be semiconductive, i.e. have a non-zero band gap. Pristine graphene is a semimetal, but by the virtue of doping the graphene surface with different molecules and radicals a band gap can be opened. Because the electronic properties of all materials are intimately related to their atomic structure, characterization of molecular and electronic structure of functionalizing groups is of high interest. The ab-inito (from the first principles) calculations provide a unique opportunity to study the influence of the dopants and thus allow exploration of the physical phenomena in functionalized graphene structures. This ability paves the road to probe the properties based on the intuitive structural information only. A great advantage of this approach lies in the opportunity for quick screening of various atomic structures. We conducted a series of ab-inito investigations of graphene functionalized with covalently and hapticly bound groups, and demonstrated possible practical usage of functionalized graphene for microelectronic and optical applications. This investigation showed that it is possible [to] produce band gaps in graphene (i.e., produce semiconducting graphene) of about 1 eV, without degrading the carrier mobility. This was archived by considering the influence of those adducts on electronic band structure and conductivity properties.

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16

Machado, Charry Fabio Eduardo. "First principles calculations of surfaces and layered materials". Doctoral thesis, Universitat Autònoma de Barcelona, 2007. http://hdl.handle.net/10803/3273.

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En este trabajo se han realizado cálculos de primeros principios para estudiar las propiedades físicas de superficies y materiales laminares. Los cálculos se basan en la obtención de las propiedades electrónicas por medio de la Teoría del Funcional de la Densidad, con la que se obtienen la energía y fuerzas atómicas para cada sistema estudiado. De esta forma, se realizaron cálculos de optimización estructural y de dinámica molecular, que proporcionan información sobre las estructuras de equilibrio y la dinámica atómica en función de las condiciones externas (tales como presión y temperatura). Los cálculos realizados se han centrado en diferentes sistemas con interés experimental, siempre en estrecha colaboración con distintos grupos experimentales. En el campo de superficies, se han estudiado problemas relacionados con el crecimiento de láminas delgadas de Cobre para metalización de circuitos microelectrónicos, la adsorción de fullerenos sobre superficies de Germanio, y la medición de ondas de densidad de carga mediante microscopía de efecto túnel en bronces azules. En materiales laminares, el trabajo se ha centrado en comprender el efecto de la presión sobre las propiedades estructurales y electrónicas de semiconductores laminares III-VI, así como en explicar la aparición de nuevas fases no-laminares para varios de estos sistemas a altas presiones.
In this work we have made first-principles calculations to study the physical properties of surfaces and layered materials. The calculations are based on obtaining the electronic properties through the Density Functional Theory, with which the energy and atomic forces for each system studied are derived. Thus, structural optimization calculations and molecular dynamics were carried out. They provide information about the equilibrium structure and the atomic dynamic as a function of external conditions (such as temperature and pressure). Calculations have focused on different systems with experimental interest, always in strong collaboration with different experimental groups. In the field of surfaces we have been studied problems associated with the growth of thin films of copper for metallization of microelectronic circuits, the adsorption of fullerenes on Germanium surfaces, and the measurement of charge density waves by scanning tunneling microscopy in bronze blue. In layered materials, the work has focused on understanding the effect of pressure on the structural and electronic properties of layered semiconductor III-VI, as well as explaining the emergence of new no-layered phases for several of these systems at high pressures.

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17

Lombard, Le Riche. "Influence of surface seal variables on bitumen bond strength properties". Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/95882.

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Thesis (MScEng)--Stellenbosch University, 2014.
ENGLISH ABSTRACT: Surface seals are widely used in South Africa. There are a number of reasons which include affordability, versatility and durability. There are, however, in some cases problems with stone loss that can lead to a shortened lifespan of the pavement. The loss of aggregate chippings in surface seals poses a major problem in the seal pavement industry. This study aims to identify the influencing factors that lead to these adhesive failures as well as to find optimum combinations of binders and aggregates at various conditions. Various binders commonly used in South African surface seal construction will be tested using the Bitumen Bond Strength (BBS) test method. The binders used in the study include 80/100 penetration grade bitumen, elastomer modified bitumen, bitumen rubber, elastomer modified emulsion and cationic rapid setting emulsion. Aggregates used in the study include dolerite, granite and quartzite. The test samples were cured and tested at two temperatures, 15 °C and 35 °C. The samples were also cured for 2, 6 and 24 hours respectively. The study tackles a wide range of variables in order to obtain a good understanding of adhesion properties of surface seals used in South Africa. Tests were repeated at least once to ensure repeatability and in some cases up to four repeats were performed. The loading rate at which the tests were performed had a significant influence on the BBS results. This rate varied which complicated the process of comparing the results. It was therefore decided to unify the loading rates. The BBS results exposed the difference between hot applied binders and emulsions. The former having significant stronger adhesion properties. It was also confirmed by the results that temperature plays a key role in the BBS results due to the visco-elastic properties of bitumen. These influences will be discussed along with others such as aggregate types and curing times. The type of failure is also discussed. Failure can either be adhesive or cohesive, the former being a failure between the aggregate and the binder while the later refers to a failure in the binder itself. The results of other students will also be discussed and compared to the results of this study. These include results of predecessors that tested emulsions as well as results from tests done on fractured aggregate surfaces and precoated aggregates. This study showed very similar results as these from other students, except for tests done with emulsions. It was discovered that the method of curing of the emulsions must be adapted to ensure proper curing of the emulsions. It was found that aggregates did not influence the BBS properties to the same extent as temperature and binder application type. The BBS results of hot applied binders also did not significantly increase as the curing time increased, but the results of emulsions showed some increase. However, the emulsions needed more time to cure properly.
AFRIKAANSE OPSOMMING: Oppervlak seëls word algemeen gebruik in Suid-Afrika. Daar is verskeie redes hiervoor waaronder bekostigbaarheid,veelsydigheid en duursaamheid. Daar is egter in sommige gevalle probleme met klipverlies wat kan lei tot n verkorte leeftyd. Hierdie klipverlies ontstaan as gevolg van verskeie redes of kombinasies daarvan. Die studie beoog om hierdie faktore wat die adhesie eienskappe beïnvloed te identifiseer sowel as om optimum kobinasies van bindmiddels en klipsoorte te bewerkstellig by verkeie kondisies. ‘n Verskeidenheid van bindmiddels wat algemeen in Suid-Afrika gebruik word, word in die studie getoets met die Bitumen Bond Sterkte (BBS) toets metode. Die bindmiddels wat in die studie gebruik word sluit 80/100 penetrasie graad bitumen, elastomeer gemodifiseerde bitumen, bitumen rubber, elastomeer gemodifiseerde emulsie en kationiese snel settende emulsie. Die klipsoorte wat vir die studie gebruikword is doleriet, graniet en kwartsiet. Hierdie gesteentes word algemeen in die praktyk gebruik. Die toets monsters word ook by twee temperature gekuur en getoets. Hierdie temperature is 15 °C en 35 °C. Die toets monsters word ook onderskeidelik vir 2, 6 en 24 uur gekuur. Die studie ondersoek 'n wye verskeidenheid van veranderlikes om sodoende 'n goeie begrip van adhesie eienskappe van die oppervlak seëls wat in Suid-Afrika gebruik word te verkry. Elke toets was ten minste een maal herhaal om herhaalbaarheid te verseker. Sommige toetse was tot 4 keer herhaal. Die belasting tempo van die toetse het ‘n beduidende uitwerking op die BBS resultate as gevolg van die visko-elastiese eienskappe van bitumen. Hierdie tempo het gewissel en dit moeilik gemaak om die resultate te vergelyk. Daarom was daar besluit om die tempo van die toetse te verander na ‘n gelykvormige tempo. Daar was ‘n duidelike verskil in BBS resultate van die warm toegepaste bindmiddels en die emulsies. Die warm bindmiddels het baie hoër BBS resultate gelwer. Dit was ook bevestig in die resultate dat temperatuur ‘n beduidende rol speel in die BBS. Hierdie invloede sal bespreek word tesame met ander, soos klipsoorte en kuring tye. Die tipe versaking word ook bespreek. Versaking kan plaasvind as gevolg van adhesie of cohesie, waar adhesie versaking 'n versaking is tussen die klip en die bindmiddel terwyl cohesie versaking verwys na 'n versaking in die bindmiddel self. Die uitslae van die ander studente sal ook bespreek word en vergelyking word met die resultate van hierdie studie. Dit sluit die resultate van voorgangers in wat emulsies getoets het sowel as die resultate van toetse wat gedoen is op gebreekte klipoppervlaktes en bitumen behandelde klippe. Hierdie studie het baie soortgelyke resultate getoon as dié van ander studente, behalwe vir die toetse wat gedoen was met emulsies. Daar is vasgestel dat die metode van kuring van die emulsies moet aangepas word om behoorlike kuring van die emulsies te verseker. Daar is ook gevind dat klipsoorte nie die BBS eienskappe in dieselfde mate as temperatuur en bindmiddel toepassingstipe beïnvloed het nie. Die BBS resultate van warm aangewende bindmiddels het ook nie aansienlik verhoog soos die kuringstyd toegeneem het nie, maar die resultate van emulsies het wel 'n toename getoon. Die emulsies het wel meer tyd nodig gehad om behoorlik te kuur.

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Kulkarni, Dhaval Deepak. "Interface properties of carbon nanostructures and nanocomposite materials". Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/49092.

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Two different interfaces were the focus of study: 1) the interface between disordered amorphous carbon and inorganic materials (metal nanostructures and silicon), and 2) the interface between partially ordered graphene (graphene oxide) and synthetic polymer matrix. Specifically, the uniqueness of this study can be summarized through the following novel findings, fabrication processes, and characterization techniques: • A simple and efficient process for faster, greener, less-expensive, and highly localized transformation of amorphous carbon nanostructures into graphitic nanostructures using low temperature heat and light treatments was developed for the fabrication of low-resistance interfaces between carbon nanomaterials and inorganic metal surfaces. • A new protocol for high resolution mapping the charge distribution and electronic properties of nanoscale chemically heterogeneous domains on non-homogeneous surfaces such as graphene oxide was established. • High strength laminated mechanical nanocomposites based on high interfacial stress transfer between polymer matrices and large area, flat, and non-wrinkled graphene oxide sheets were suggested and demonstrated. • Scanning Thermal Twist Microscopy – a thermal microscopy based technique was developed and demonstrated for characterizing the thermal properties of homogeneous and heterogeneous interfaces with nanoscale spatial resolution and high thermal sensitivity unachievable using traditional techniques.

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19

Hartschuh, Ryan D. "Optical Spectroscopy of Nanostructured Materials". University of Akron / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=akron1195016254.

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20

Chai, Zheng. "Materials chemistry : structures and properties of organic self-assembled monolayers on gold surfaces /". Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.

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Mohamedi, Graciela. "Engineering the surface properties of microbubbles for biomedical applications". Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:e68f2010-19b6-45af-b238-da8e2d29b270.

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Surfactant coated microbubbles are widely used as contrast agents (UCA) in medical ultrasound imaging, due to their high echogenicity and non-linear response to acoustic excitation. Controlling the stability of microbubbles in vivo represents a considerable challenge. Understanding the characteristics of the bubble surface and how they change with production method, composition and environment is key to addressing this problem. The aim of this thesis is to investigate viscosity, bubble dissolution, and acoustic response as functions of their composition, manufacturing method and environment. Bubbles were made using combinations of phospholipid and an emulsifier in different molar ratios. Adding the emulsifier decreased both the size and the surface viscosity of the bubbles and caused changes in the scattered pressure amplitude of bubbles under ultrasound. To increase microbubble stability, solid inorganic nanoparticles were adsorbed on to the microbubble surface. These particles behaved as Pickering stabilisers, and deterred Ostwald ripening. The nanoparticles also enhanced the nonlinear behaviour of bubbles at low acoustic pressures. Three manufacturing methods (sonication, cross-flow and flow focusing) were investigated in order to verify stability differences. Sonication produced bubbles with surface viscosities hundreds of centipoise greater than those produced by microfluidics. Both pressure amplitude and harmonic content for sonicated bubbles were found to be much larger due to a higher liposomal adhesion rate at the surface. Solution temperature and bubble age were also investigated. When the solutions were heated above the phospholipid gelling temperature, microfluidic bubbles showed an increased surface viscosity, due to increased liposome adhesion caused by the increased temperature. Bubble composition, manufacturing method and environment were found to vary the surface characteristics of the microbubbles. Further investigations into the affects of the filling gas, in vitro studies, and low temperature TEM characterisation should be conducted to produce a microbubble with the full range of desired characteristics.

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22

Ahmad, Mansur. "Analysis of Calcutta bamboo for structural composite materials". Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/28742.

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Land use issues have dramatically changed the timber supply outlook for our nation's forest products industry. Since demand for wood products shows no sign of abating, alternative products must be developed. Bamboo is a very promising alternative raw material for the manufacture of structural composite products. It is fast growing, economical, renewable and abundant throughout the world. Bamboo has physical and mechanical properties that are comparable to many commercial timber species, and thus, may easily be processed using existing technology from the wood-based composites industry. Bamboo can be cultivated in the U.S., and thus has the potential to relieve some of the harvesting pressure from our nation's forestlands. However, the use of specific bamboo species for structural composite products will require a thorough investigation of the material as well as its interaction with other components. Thus, the primary objective of this dissertation is to determine the properties of Calcutta bamboo and its interaction with adhesives. The properties investigated were relative density, dimensional stability, equilibrium moisture content, bending strength and stiffness, tensile strength, pH, buffer capacity, wettability and the adhesive penetration. In addition to this, a prototype bamboo parallel strip lumber (BPSL) was manufactured and tested for its physical and mechanical properties. The relationships among the properties of Calcutta bamboo and the prototype bamboo composite were also investigated. As the result of these investigations, it is concluded that Calcutta bamboo is technically a suitable raw material for structural composite products. This result may also be applicable for the utilization of other bamboo species, thus aiding companies in decisions regarding investment in bamboo plantations and manufacturing facilities in the U.S, Malaysia and other parts of the world. The primary benefits from this research may be the development of new products to serve growing markets, and thereby relieving some of the pressure to harvest forestlands.
Ph. D.

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23

Booth, Samantha E. "Surface properties and the bioactivity of glass-ionomer dental cements and related materials". Thesis, University of Greenwich, 2010. http://gala.gre.ac.uk/5716/.

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The improvement and modification of the surface hardness of glass-ionomer dental cements was investigated in the studies discussed in this thesis to allow the range of clinical applications of these cements to be extended. Storing the cements in non-aqueous media whilst heating at 60 oC increased the surface hardness compared to storage in water at 37 oC. The corresponding compressive strength showed no significant changes. The bioactivity of two commercially available glass-ionomer dental cements was investigated after it was established that the surface hardness of a dental cement was improved by storing the materials in biologically natural bovine milk. In particular the observations of the appearance of the surface were noted as well as cation release studies and calcium to phosphorus ratios calculated. The results indicated that a surface layer of calcium phosphate had formed and created a barrier around the cement preventing the loss of strengthening ions. An investigation was also made into formulating a novel hybrid cement. This process included the deployment of additives/co-reactants within the cement formulation. By incorporating zinc phosphate into a strontium based glass-ionomer elevated levels of fluoride release were obtained when compared to the original commercially available glass-ionomer. SEM images show that this additive had an effect on the surface morphology of the glass. The bioactivity studies performed on these cements show the uptake of calcium over one week, indicating that there is the possibility that these new hybrid cements are bioactive. Refinement of the new hybrid materials has produced cements with antimicrobial properties as well as higher surface hardness values than the original glass-ionomer.

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Black, Sean C. E. "The effect of abrasive properties on the surface integrity of ground ferrous materials". Thesis, Liverpool John Moores University, 1996. http://researchonline.ljmu.ac.uk/5100/.

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The effect of the thermal properties of alumina and CBN abrasives on workpiece temperatures in grinding was investigated. A review of the literature revealed a lack of knowledge of the thermal properties of CBN limiting the accuracy of theoretical predictions of the heat conduction in CBN grinding. A grain contact analysis was developed to predict the energy partitioning between the workpiece and wheel. The analysis takes into account two dimensional transient heat transfer in the grain and maintains temperature compatibility at the grain wear flatworkpiece interface. The proportion of the total grinding energy entering the workpiece, termed the partition ratio, was estimated by correlating measured temperature distributions with theoretical distributions. The partition ratios when grinding with CBN were substantially lower than grinding with alumina wheels for a range of ferrous materials. The lower partition ratios with CBN grinding were attributed to the higher thermal conductivity of the CBN abrasive. The effective thermal conductivity of alumina and CBN grains were quantified by correlating the theoretical partitioning model with the measured results. The effective thermal conductivity of CBN was found to be considerably lower than the reported theoretical value albeit much higher than the effective thermal conductivity of alumina. A model to predict the background temperature in grinding was proposed based on the experimental findings. The thermal model takes into account a triangular heat flux distribution in the grinding zone, the real length of contact and experimentally validated grain thermal properties. The input parameters to the thermal model were specified. To avoid temper colours on the workpiece surface the maximum background temperature must not exceed 450 to 500deg. C. for commonly used ferrous materials.

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Krishnaswamy, Anand. "Evaluation of surface mechanical properties of pot hardware materials in continuous galvanizing lines". Morgantown, W. Va. : [West Virginia University Libraries], 2005. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=3828.

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Thesis (M.S.)--West Virginia University, 2005
Title from document title page. Document formatted into pages; contains xii, 71 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 59-61).

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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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27

Lee, Jihoon. "Cellulosic nanocomposites with unique morphology and properties". Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37149.

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Cellulose nanowhiskers reinforced poly(vinyl alcohol)(PVA) nanofiber web is successfully fabricated using electrospinning technique and the mechanical properties of the single electrospun fiber are measured using nanoindentation method. The morphology and mechanical properties of highly aligned electrospun fiber webs are investigated. It is found that the modulus and tensile strength of aligned webs are higher than those of isotropic electrospun fiber webs. Experimental results are compared with a longitudinal Halpin-Tsai model. Ice-templated(IT) cellulose microfibril porous foams are successfully fabricated via unidirectional freezing methods. The morphology and growth mechanism of IT surfaces are investigated successfully using cellulose microfibrils and hydrophillic substrates. By controlling the temperature gradient between cellulose microfibril suspensions and secondary freezing mediums, various surface structures including honey-comb like structures, ellipse-shape channel strcutures, fully developed multichannel structures are obtained. For the honey-comb like patterned surface, high contact angles are observed. On the other hand, for the layered patterned surface, anisotropic wetting properties are observed.

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28

Ye, Miao Ph D. Massachusetts Institute of Technology. "Reversible stimulus-responsive polymers for the control of the surface interfacial and nanomechanical properties". Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/44318.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2008.
Includes bibliographical references (leaves 111-122).
Surfaces with reversible stimulus-responsive properties have great potential for a wide variety of applications, such as transport, separation, and detection of biomolecules, controlled adhesion, friction, and lubrication in microfluidic systems, and force or displacement generation in micro- and nanoscale devices. Surface bound stimulusresponsive polymers are ideal candidates for above applications due to their conformational sensitivity to many stimuli with controlled molecular weight, composition, architecture and topology. In this thesis, one particular class of stimulus-responsive polymers, pH-sensitive comb-type graft copolymers with ionizable main chain segments was investigated. Mono(end)-functional thiol-terminated poly(methacrylic acid-gethylene glycol) (HS-poly(MAA-g-EG)) with three different macromolecular architectures (number average molecular weight, Mn = 27K, PEG graft density, PEG(%) = 7.7%, backbone contour length, Lcontour= 41.1 nm; Mn= 15K, PEG(%) = 8.8%, Lcontour = 22.1 nm; Mn = 17K, PEG(%)= 1.9%, Lcontour = 39.8 nm) have been synthesized via atomic transfer radical polymerization and characterized by 'H NMR, GPC and FT-IR. Stimulus responsive surfaces were prepared via chemically end-attached "brush-brushes" formed by chemisorption of the copolymers on Au substrates. Chemically specific high resolution force spectroscopy (HRFS) was carried out with probe tips (end radius-50 nm) functionalized with HS(CH2)10COOH (a carboxy-terminated selfassembling monolayer or COOH-SAM) to measure the normal nanoscale interaction forces, F, as a function of probe-tip sample separation distance, D,in a series of aqueous buffer solutions of varied pH (=4-9) and constant ionic strength (IS=0.005M NaC1).
(cont.) The higher PEG grafting density surfaces (27K, 15K) exhibited the unique property of "nanomechanical switching" with pH, i.e. the normal intersurface force inverted from net repulsive (high pH, ionized uncomplexed side chains) to net attractive (low pH, sidechain/main-chain hydrogen bonding complexation). The 17K polymer brushes did not exhibit nanomechanical switching and maintained a slightly repulsive intersurface force at low pH. Surface plasmon resonance (SPR) was employed to assess the adsorption of human serum albumin (HSA) to these poly(MAA-g-EG) brushes in aqueous buffer solutions of varying pH. Polymers with a higher grafting density of hydrophilic PEG side chains and longer polymer backbones showed much less HSA adsorption at high pH and more protein adsorption at low pH. Surprisingly, HSA adsorption was found to be greatly amplified at intermediate pH6 (~1.4-1.8 x greater than that of the hydrophobic state of polymer layers at pH4). Higher PEG grafting density and a longer polymer backbone demonstrated larger protein adsorption amplification at pH6, which may be due to increased molecular mobility/disorder at a metastable state of the conformational transition. For the lateral force interaction between the end-grafted polymer layers and a probe tip (nominal radius - 50 nm) functionalized with OH-SAM (HS(CH2)11OH), as pH decreased, both the 27K and 17K polymer layers exhibit an abrupt change in lateral proportionality coefficient (ratio of lateral force to normal force) between pH7.1 and pH6 with larger lateral proportionality coefficients, [mu] ~ 0.63-0.89 at pH 4-6 and decreased [mu] ~ 0.12-0.34 at pH 7.1-9.
(cont.) The 27K polymer had relatively higher p values at pH < 6 (0.89±0.19) but smaller [mu] at pH > 7.1 (0.21±0.04) than the 17K polymer, indicating that a more dramatic change in lateral force coefficient is expected for stimulus-responsive graft copolymers with higher side chain grafting densities.
by Miao Ye.
Ph.D.

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Chanda, Jagannath. "Design of multifunctional materials with controlled wetting and adhesion properties". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-200803.

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Ice accretion on various surfaces can cause destructive effect of our lives, from cars, aircrafts, to infrastructure, power line, cooling and transportation systems. There are plenty of methods to overcome the icing problems including electrical, thermal and mechanical process to remove already accumulated ice on the surfaces and to reduce the risk of further operation. But all these process required substantial amount of energy and high cost of operation. To save the global energy and to improvement the safety issue in many infrastructure and transportation systems we have to introduce some passive anti-icing coating known as ice-phobic coating to reduce the ice-formation and ice adhesion onto the surface. Ice-phobic coatings mostly devoted to utilizing lotus-leaf-inspired superhydrophobic coatings. These surfaces show promising behavior due to the low contact area between the impacting water droplets and the surface. In this present study we investigate systematically the influence of chemical composition and functionality as well as structure of surfaces on wetting properties and later on icing behavior of surfaces. Robust anti-icing coating has been prepared by using modified silica particles as a particles film. Polymer brushes were synthesized on flat, particle surfaces by using Surface initiated ATRP. We have also investigated the effect of anti-icing behavior on the surfaces by varying surface chemistry and textures by using different sizes of particles. This approach is based on the reducing ice accumulation on the surfaces by reducing contact angle hysteresis. This is achieved by introducing nano to micro structured rough surfaces with varying surface chemistry on different substrates. Freezing and melting dynamics of water has been investigated on different surfaces by water vapour condensation in a high humidity (80%) condition ranging from super hydrophilic to super hydrophobic surfaces below the freezing point of water. Kinetics of frost formation and ice adhesion strength measurements were also performed for all samples. All these experiments were carried out in a custom humidity and temperature controlled chamber. We prepared a superhydrophobic surface by using Poly dimethyl siloxane (PDMS) modified fumed silica which display very low ice-adhesion strength almost 10 times lower than the unmodified surface. Also it has self-cleaning behavior after melting of ice since whole ice layer was folded out from the surface to remove the ice during melting. Systematic investigation of the effect of three parameters as surface energy, surface textures (structure, geometry and roughness) and mechanical properties of polymers (soft and stiff) on icing behavior has also been reported.

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30

Bai, Fan. "Investigation of optical properties of one-dimensional nanostructures with engineerable heliciity and surface modification". HKBU Institutional Repository, 2017. https://repository.hkbu.edu.hk/etd_oa/437.

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In this work, the optical properties of two kinds of one-dimensional (1D) nanomaterials, mesoporous silicon nanowires (mpSiNWs) and plasmonic nanospirals (NSs), were studied. These emerging nanomaterials are of great interest because of their fundamental structure-derived properties and potential practical applications. Four aspects of these materials were analyzed in this work. First, although the fabrication mechanism of mpSiNWs has been studied previously via metal-assisted chemical etching, the porosification-induced disturbance to the etching direction, which plays a vital role in controlling the surface crystallinity of mpSiNWs, has not been characterized. In Chapter 2, I discuss the porosification etching mechanism of n-Si(111), which proceeds along the intrinsic back bond etching direction of [111] at room temperature. The porosification substantially weakens the back bonds under the sinking particles, resulting in the deviation of etching from [111]. The preferred direction of etching changes to that with a small angle α, because the direction-switching barrier increases with α and intrinsic back-bond etching is thermodynamically preferential. Second, mpSiNWs typically generate red photoluminescence (PL), but the PL mechanism is still under debate. A laser was used to oxidize the surfaces of mpSiNWs and tune the PL from red to greenish-blue (GB), as described in Chapter 3. The laser oxidation was tuned as a function of laser power, and a complex model of the laser-induced surface modification was proposed to account for the laser-power and post-annealing effect. The laser-induced modification of the PL of mpSiNWs may be useful for data encryption. Third, the fabrication of plasmonic NSs and the study of their optical activities are in their infancy. In Chapter 4, I describe the use of glancing-angle deposition (GLAD) to fabricate silver NSs (AgNSs) with controllable helicity and demonstrate that AgNSs have intrinsic optical responses that originate from their structural helicity. The optical activity of an AgNSs dispersion was characterized by circular dichroism (CD), and systematic engineering of the helicity revealed that their UV and visible optical activities have two different origins. Fourth, physical limits prohibit the sensitive differentiation of enantiomers. In Chapter 5, I describe the grafting of chiral molecules onto AgNSs, which dramatically enhanced the differentiation of L- and D-glutathione (GSH). AgNSs have very strong optical activities that are weakened by GSH adsorption. The severity of the chiroptical weakening effect varies with the absolute configuration of GSH, resulting in enantiomeric differentiation with an anisotropic g-factor of approximately 0.5. This chiral nanoplasmon-induced anisotropy g-factor is superior by 2 to 4 orders of magnitude to those obtained with other methods and about one-fourth of the theoretical value. This proposed method can be adapted to differentiate chiral drugs, which is highly desirable in the pharmaceutical industry for the production of single-enantiomer drugs.

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Cordoba, Erazo Maria Fernanda. "Near-field Microwave Microscopy for Surface and Subsurface Characterization of Materials". Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5930.

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This dissertation presents an investigation on the capabilities of Near-Field Microwave Microscopy (NFMM) for the characterization of surface and subsurface materials. Subsurface characterization refers to the detection, differentiation and imaging of dielectric, and metallic features that are coated with an insulating layer. The design, simulation and modeling, and testing of a dielectric resonator (DR)-based NFMM and a coaxial transmission line resonator-based NFMM are discussed in detail in this work. Additionally, materials differentiation and imaging capabilities of each microscope are examined using several bulk samples, liquids, GaAs MMIC circuits, and gold/glass testing patterns. The 5.7 GHz DR-based NFMM uses a microwave probe that consists of a commercial gold-coated probe tip coupled to a DR through a non-resonant microstrip line. The probe is enclosed in an aluminum cavity to preserve the quality factor of the probe (Q=986) and therefore to enhance its sensitivity. The development of a lumped-element model of this DR-based probe is discussed in this work. Characteristics of this design are its high Q and the ability to resolve differences in permittivity (E’r) of insulting bulk samples and liquids as small as ∆E’r =1.75 and ∆E’r =0.04, respectively. The imaging capabilities of this design were verified using a GaAs MMIC phase shifter. It was found that a 10 um wide microstrip line is successfully resolved and that the spatial resolution of the microscope is 50 um when using a tungsten tip with an apex radius of 25 um. Additionally, measurement of the electrical resistance of an additive manufactured resistor was measured using the DR-based NFMM without the need of contacts. The percent difference between the electrical resistance measured using the DR-based NFMM and a four-point probe is 9.6%. Furthermore, the DR-based NFMM allows simultaneous imaging of topography and RF electrical conductivity of rough thick films without the need of an additional distance sensor; this ability is demonstrated for a rough CB028 thick film. The 5GHz coaxial resonator transmission line-based NFMM employs a half-wavelength coaxial transmission line resonator terminated in a sharp tungsten tip as the microwave probe. A quartz-tuning fork based distance following feedback system is integrated with the microwave probe in order for the NFMM to operate in non-contact mode. The Q of the probe is degraded by 30% (Q=55) due to the presence of the quartz tuning fork. Despite the low Q, this NFMM is able to differentiate several insulating bulk samples (3.8 < E’r < 25) even if they are coated with an insulating layer of thickness similar to the apex radius of the tungsten tip. Finally, the coaxial resonator transmission line-based NFMM is able to image subsurface permittivity distribution of a flexible polymer-composite PDMS-Ba0.55Sr0.45TiO3 49% which is coated with 10 um thick parylene-C layer. Measurements performed at a tip-sample distance of 100 nm reveal that within an area of 50 um x 50 um, the relative permittivity of the polymer-composite is not constant but varies between 6.63 and 11.78.

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Komlijenovic, Dario. "Surface Expressions : To investigate reverse applique technique in relation to recognizable garments inspired by sportswear/streetwear in order to find new surface expressions". Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-26318.

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The degreework is based on an ancient technique called Reverse appliqué which is popular among the Kuna Indians with their Mola blouse and in Hmong textile art. There are various ways of using the technique. The basic method which I have been focusing my work on is where two or more layers are put together, the motif is then stitched through the layers either by hand or machine stitched, one or more layers is then cut open around the edges of the motif in order to reveal the next coming layer. I believe this technique has not been explored enough in terms of materials with various properties, layers,and textures resulting in the same generic surface expression. This work looks for various ways to use these elements in order to find new surface expressions. The result is a collection which suggests new ways of approaching the technique with a variety of mixed surface expressions such as by exploring various stitch tension into the technique, or by using the material itself as the keystone into the technique when creating the material and not only as one of the layers. More importantly the multiple material explorations that was conducted throughout this study indicates the amount of possibilities this technique has to offer for further exploration. It is also a suggestion to use materials that might not be considered as the right proper materials for streetwear, sportswear looks which in the end surprised me will the collection surprise you?

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Minguela, Díaz Joaquim. "Surface characterization and cell instructive properties of superficially modified dental zirconia". Doctoral thesis, TDX (Tesis Doctorals en Xarxa), 2021. http://hdl.handle.net/10803/672324.

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Tetragonal polycrystalline zirconia doped with 3 mol% yttria (3Y-TZP) has become one of the most popular dental ceramics. Thanks to its outstanding mechanical properties (including high hardness. Toughness and wear resistance).Biocompatibility and white color. It is now commonly employed to produce components such as crowns, implants, abutments, bridges or posts and cores. In the case of dental implants, which are directly screwed into the jawbone, implant's surfaces can be modified through different physical or chemical techniques to ensure a rapid and proper osteointegration. In the first case, surface topography is known to play a critica! role in cell-material interactions and to influence several cell functions such as adhesion, proliferation or differentiation. In the second case, specific chemical cues such as integrin-binding peptidic molecules from bone extracellular matrix can affect cell behavior with a high degree of specificity. The combination of both strategies may provide a powerful tool to obtain an improved bone-to-implant contact and ensure long lasting implants. In this Ph.D. Thesis a dual approach employing surface topographical modification and peptidic biofunctionalization on dental zirconia is explored, with the aim of providing a flexible tool to improve tissue integration of ceramic restorations. Regarding surface topographical modifications, two different strategies are investigated: grinding and laser-micropatterning. Both of them can generate not only rough surfaces at the micro- and submicrometric length scale but also other features such as grooves, which may guide cell growth. However, these two techniques are based on different principies. While in grinding technique the material is removed by a mechanical process, laser patterning is based on the thermal effects of absorbed photons. However, these methods are not exempt from introducing a certain degree of surface damage, which can be detrimental for the final application. In addition, 3Y-TZP is susceptible of a spontaneous surface phase transformation from tetragonal (t-) to monoclinic (m-) phase under two different scenariu . One is known as transformation toughening and it is a stress-assisted mechanism accompanied by a volume increase (4%) activated by the near tip crack stress field, which increase crack propagation resistance. On the other hand, a second scenario exists known as low temperature degradation (LTD). In this case, aging by progressive t- to m- transformation at the surface is triggered by water molecules. In this particular case, this mechanism induces roughening and micro-cracking, which can drastically reduce the mechanical properties and in particular the wear resistance by generating pull-out of 3Y-TZP grains. In this regard, sorne surface treatments can affect the LTD resistance of the material, or even induce this phase transformation. Far these reasons, a particular emphasis is placed on the changes in the surface and subsurface introduced by both methods. Damage, microstructure, phase transformation and residual stresses are characterized, as well as its effects on LTD and mechanical properties. On the other hand, peptidic biofunctionalization is carried out by using a peptidic platform that incorporates the cell-adhesive RGD and the osteogenic DWIVA motives. This strategy is combined with the best performing topography-modifying treatment. On this surface that integrales the stimuli provided by topography and the peptides, cell adhesion, cell migration and osteogenic properties are characterized in detail.
La zircònia policristal·lina tetragonal dopada amb un 3% d'itria (3Y-TZP) s'ha convertit en una de les ceràmiques dentals més populars. Gràcies a les seves excel·lents propietats mecàniques (inclosa l'altra duresa, tenacitat i resistència al desgast), la biocompatibilitat i el color blanc, ara s'utilitza habitualment per produir components com corones, implants o ponts. En el cas d'implants dentals, que es cargolen directament a l'os de la mandíbula, les superfícies de l'implant es poden modificar mitjançant diferents tècniques físiques o químiques per garantir una osteointegració rapida i adequada. En el primer cas, se sap que la topografia superficial té un paper crític en les interaccions cél·lula-material i que influeix en diverses funcions cel·lulars com ara l'adhesió, la proliferació o la diferenciació. En el segon cas, els estímuls químics específics com els que indueixen les molècules peptídiques de la matriu extracel·lular óssia poden afectar el comportament cel·lular amb un alt grau d'especificitat. La combinació d'ambdues estratègies pot proporcionar una eina poderosa per obtenir una millor interacció entre l'os i l'implant i garantir una vida llarga als implants. En aquesta tesis doctoral s'explora una estratègia dual que utilitza la modificació superficial de la topografia i la biofuncionalització peptídica sobre zircònia dental, amb l'objectiu de proporcionar una eina flexible per millorar la integració amb els tebcits de les restauracions ceràmiques. Pel que fa a les modificacions superficials de la topografia, s'estudien dues estratègies: rectificat i micro-patrons làser. Tots dos poden generar no només superfícies rugoses a l'escala micro- i submicromètrica, sinó també altres característiques com ara canals/solcs, que poden guiar el creixement cel·lular. Tot i això, aquestes dues tècniques es basen en principis diferents. Mentre que en la tècnica de rectificat el material s'elimina mitjançant un procés mecànic, el patró làser es basa en els efectes tèrmics dels fotons absorbits. No obstant això, aquests mètodes no estan exempts d'introduir un cert grau de dany a la superfície, que pot ser perjudicial per a l'aplicació final. A més, la 3Y-TZP és susceptible d'una transformació espontània de fase des de la fase tetragonal (t-) a la monoclínica (m-) sota dos escenaris diferents. Un es coneix coma augment de tenacitat per transformació de fase ("transformation toughening", en anglès) i és un mecanisme activat per esforços acompanyat d'un augment de volum (4%). Aquest procés esta activat pel camp d'esforços proper a una esquerda, augmentant la resistència a la propagació de les esquerdes. D'altra banda, existeix un segon escenari conegut com degradació a baixa temperatura ("low temperature degradation", en anglès) . En aquest cas, la progressiva transformació de t- a m- a la superfície és provocada per les molècules d'aigua. Aquest mecanisme indueix rugositat i micro-esquerdes a la superficie, que poden reduir dràsticament les propietats mecàniques i, en particular, la resistència al desgast. En aquest sentit, alguns tractaments superficials poden afectar la resistencia a la degradació del material o fins i tot induir aquesta transformació de fase. Per aquestes raons, es fa un èmfasi especial en els canvis en la superfície introduïts per tots dos mètodes. Es caracteritzen els danys, la microestructura, la transformació de fase i les tensions residuals, així com els seus efectes sobre les propietats mecaniques i la degradació a baixa temperatura. D'altra banda, la biofuncionalització peptídica es realitza mitjançant una plataforma peptídica que incorpora el motiu adhesiu RGD i el motiu osteogènic DWIVA. Aquesta estratègia es combina amb el tractament modificador de la topografia amb el millor rendiment (rectificat o micro-patrons làser). En aquesta superfície que integra els estímuls proporcionats per la topografia i els pèptids, es caracteritzen detalladament l’adhesió cel·lular, la migració cel·lular i les propietats osteogèniques.
Ciència i enginyeria de materials

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34

Meng, Han. "Acoustic properties of novel multifunctional sandwich structures and porous absorbing materials". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEC008/document.

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La mise en oeuvre de matériaux acoustiques est une méthode efficace et très utilisée pour réduire le bruit le long de sa propagation. Les propriétés acoustiques de nouvelles structures sandwich multifonctionnelles et de matériaux absorbants poreux sont étudiées dans la thèse. Les principales contributions de la thèse sont les suivantes: Les panneaux sandwich ont généralement d'excellentes propriétés mécaniques et un bon indice de perte en transmission sonore (STL), mais aucune capacité d'absorption acoustique. De nouvelles structures sandwich multifonctionnelles sont développées en intégrant des microperforations et des matériaux absorbants poreux aux panneaux sandwich ondulés et en nid d’abeilles conventionnels, structurellement efficaces pour obtenir de bons STL et de bonnes absorptions en basses fréquences. Le coefficient d'absorption acoustique (SAC) et la perte en transmission (STL) des panneaux sandwich ondulés sont évalués numériquement et expérimentalement en basse fréquence pour différentes configurations de perforations. Les modèles éléments finis (EF) sont construits en tenant compte des interactions vibro-acoustiques sur les structures et des dissipations d'énergie, visqueuse et thermique, à l'intérieur des perforations. La validité des calculs FE est vérifiée par des mesures expérimentales avec les échantillons testés obtenus par fabrication additive. Par rapport aux panneaux sandwich ondulés classiques sans perforation, les panneaux sandwich perforés (PCSPs) avec des perforations dans leur plaque avant présentent non seulement un SAC plus élevé aux basses fréquences, mais aussi un meilleur STL, qui en est la conséquence directe. L'élargissement des courbes des indices d’absorption et de transmission doit être attribué à la résonance acoustique induite par les micro-perforations. Il est également constaté que les PCSPs avec des perforations dans les plaques avant et les parois internes onduleés ont les fréquences de résonance les plus basses de tous les PCSPs. En outre, les performances acoustiques des panneaux sandwich en nid d'abeilles avec une plaque avant microperforée sont également examinées. Un modèle analytique est présenté avec l'hypothèse que les déplacements des deux plaques sont identiques aux fréquences inférieures à la fréquence de résonance des plaques. Le modèle analytique est ensuite validé par des modèles d'éléments finis et des résultats expérimentaux existants. Contrairement aux panneaux sandwich en nid d'abeilles classiques qui sont de piètres absorbeurs de bruit, les sandwichs en nid d'abeilles perforés (PHSPs) conduisent à un SAC élevé aux basses fréquences, ce qui entraîne en conséquence un incrément dans le STL basse fréquence. Les influences de la configuration du noyau sont étudiées en comparant les PHSPs avec différentes configurations de noyaux en nids d'abeilles. […]
Implementation of acoustic materials is an effective and popular noise reduction method during propagation. Acoustic properties of novel multifunctional sandwich structures and porous absorbing materials are studied in the dissertation. The main contributions of the dissertation are given as, Sandwich panels generally have excellent mechanical properties and good sound transmission loss (STL), but no sound absorption ability. Novel multifunctional sandwich structures are developed by integrating micro perforations and porous absorbing materials to the conventional structurally-efficient corrugated and honeycomb sandwich panels to achieve good SAC and STL at low frequencies. Low frequency sound absorption and sound transmission loss (STL) of corrugated sandwich panels with different perforation configurations are evaluated both numerically and experimentally. Finite element (FE) models are constructed with considerations of acousticstructure interactions and viscous and thermal energy dissipations inside the perforations. The validity of FE calculations is checked against experimental measurements with the tested samples provided by additive manufacturing. Compared with the classical corrugated sandwich panels without perforation, the perforated corrugated sandwich panels (PCSPs) with perforations in its face plate not only exhibits a higher SAC at low frequencies but also a better STL as a consequence of the enlarged SAC. The enlargement of SAC and STL should be attributed to the acoustical resonance induced by the micro perforations. It is also found that the PCSPs with perforations in both the face plates and corrugated cores have the lowest resonance frequencies of all the PCSPs. Besides, the acoustic properties of honeycomb sandwich panels with microperforated faceplate are also explored. An analytical model is presented with the assumption that displacements of the two faceplates are identical at frequencies below the faceplate resonance frequency. The analytical model is subsequently verified by finite element models and existing experimental results. Unlike classical honeycomb sandwich panels which are poor sound absorbers, perforated honeycomb sandwiches (PHSPs) lead to high SAC at low frequencies, which in turn brings about increment in the low frequency STL. Influences of core configuration are investigated by comparing PHSPs with different honeycomb core configurations. In order to enlarge the SAC bandwidth of perforated sandwich panels, porous absorbing materials are added to the cores of novel perforated sandwich panels. FE models are set up to estimate the SAC and STL of perforated sandwich panels with porous materials. Results show that perforated sandwich panels with porous material can provide SAC with broader bandwidth and lower resonance frequency than that without porous materials. Whereas the peak values in the SAC and STL curves are reduced due to the weakened acoustical resonance by the porous materials. […]

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Musa, Mohamed Osman. "Resonance properties of surface plasmon polaritons and their applications to detection of gaseous materials". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ39862.pdf.

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36

Mauder, Daniel. "Investigation of structure and surface properties of mesoporous silica materials by solid state NMR". Berlin mbv, Mensch-und-Buch-Verl, 2009. http://d-nb.info/998069116/04.

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Chan, Chi Lun. "Alp-CuInSe2 tunnel MIS Schottky diodes & surface properties of crystalline p-CuInSe2". Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61911.

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38

Gustafsson, Sofia. "Corrosion properties of aluminium alloys and surface treated alloys in tap water". Thesis, Uppsala universitet, Institutionen för materialkemi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-157527.

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The aim of this thesis is to obtain a basic knowledge of the factors that affect corrosion of aluminium in tap water for different kinds of applications like water pipes for tap water, solar systems, HVAC&R-applications (like fan coil units on chillers) and heat sinks for electronic or industrial applications. Open systems are used in some applications and closed systems in others. There is a clear difference in the corrosion behaviour of these two systems. The main reasons for this difference are that the content of oxygen differs between the two systems and also that inhibitors can be used in closed systems to hinder corrosion. In this thesis focus will be on corrosion in open systems. The corrosion properties in tap water for different alloys of aluminium and different surface treatments have been examined. The influences on corrosion of the oxygen content in water and the iron content in aluminium alloys have been investigated. The corrosion properties of an aluminium alloy in deionised water have also been examined.

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39

Link, Stephen. "Spectral properties and relaxation dynamics of surface plasmon electronic oscillations in gold and silver nanodots and nanorods". Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/30706.

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40

Vase, Ajoy. "The effects of material treatments on the surface properties of polymeric biomaterials". Pomona College, 2007. http://ccdl.libraries.claremont.edu/u?/stc,19.

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This work examines the chemical and physical effects of a material treatment process on the biopolymers PEEK, POM-h, POM-c, PTFE and UHMWPE. The polymers are analyzed physically and chemically using atomic force microscopy, profilometry, scanning electron microscopy, optical microscopy, contact angle measurement, FT infra-red spectroscopy and energy dispersive X-ray spectrometry. PEEK is found to be the most suitable polymer and FT Infra-red spectroscopy an informative analytic tool.

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41

Marciszko, Marianna. "Diffraction study of mechanical properties and residual stresses resulting from surface processing of polycrystalline materials". Thesis, Paris, ENSAM, 2013. http://www.theses.fr/2013ENAM0037/document.

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Méthodologie de mesures de contraintes avec la méthode multireflection pâturage d'incidence(MGIXD) a été étudié et développé. La géométrie du faisceau parallèle a été appliquée pour mensurationsde stress. Le faisceau incident dans diffractomètres classiques a été collimaté par le miroir Göbel et lesessais de configuration en parallèle ont été effectuées pour Al poudre. Les résultats confirmé que le erreurstatistique et l'erreur d'alignement peuvent être réduits lorsque le miroir Göbel est utilisé. Facteursphysiques ont été prises en compte dans la CSX (analyse aux rayons X du stress): Lorentz - polarisationet facteur d'absorption (LPA) et aussi correction de la réfraction (RC). Les résultats montrent quel'influence de LPA est mineur dans CSX, mais la RC peut influencer de manière significative l'analyse.Dans la thèse de la question de RC a été examiné et comparé avec les approches présentées dans lalittérature. Dans la thèse de deux développements théoriques de la méthode MGIXD ont été présentés: laprocédure de détermination de paramètre c/a et l'influence des défauts d'empilement sur les résultats. Il aété montré que les deux développements améliore de manière significative la qualité de l'analyse desdonnées expérimentales. Dans le présent travail le problème de la X -ray facteurs de stress (XSF) utiliséspour l'interprétation des résultats CSX a été étudiée. Différents modèles théoriques de grains élastoplastiqueinteraction ont été envisagées et appliquées dans la CSX. Vérification de la XSF durant l'essaide traction pour l'échantillon élastique anisotrope (en acier inoxydable austénitique) et pour l'échantillonisotrope (Ti - note2). Anisotropie de XSF a également été observée dans: rectifié alliage Ni, acierinoxydable austénitique poli et revêtement CrN. Les résultats montre que Reuss et modèle de la surfacelibre sont en meilleur accord avec les résultats expérimentaux. Enfin, la méthode MGIXD a été vérifiée enutilisant le rayonnement synchrotron et 3 longueurs d'onde différentes. La méthodologie a été développéepour traiter les données non seulement pour les différents angles d'incidence, mais aussi en utilisantdifférentes longueurs d'onde simultanément. Contraintes en fonction de «vraie profondeur» a été calculéeen utilisant la transformée de Laplace inverse. Analyse Wiliamson-Hall a été appliquée pour les données.Méthode MGIXD a été appliqué pour les mesures de diffraction de dispersion d'énergie dans lequel lefaisceau blanc a été utilisé: 0,3 à 0,18 Å. L' analyse des contraintes a été effectuée en utilisant troisméthodes différentes : la méthode de sin2ψ norme, la méthode de terrain universelle et en utilisantmultireflection analyse . Dans la gamme de profondeur de pénétration à 0-15 um de la convergence desrésultats obtenus à partir de différentes méthodes a été acquise . En outre, les données de synchrotronparfaitement en accord avec les résultats obtenus en laboratoire sur diffractomètre (rayonnement Cu Ka) àproximité de la surface . Pour profondeur supérieure à 14 um points expérimentaux présentent desvariations importantes et ne sont pas d'accord avec les résultats de la méthode standard.Mots clés : contraintes résiduelles, diffraction des rayons X, méthode de l’incidence rasante, miroir Göbel
Methodology of stress measurements with multireflection grazing incidence method (MGIXD)was investigated and developed. The parallel beam geometry was applied. The incident beam in classicaldiffractometers was collimated by Göbel mirror and the tests of parallel configuration were performed for Alpowder. Results confirmed that both statistical error and the misalignment error can be reduced when theGöbel mirror is used. Physical factors were taken into account in XSA (X-ray stress analysis): Lorentzpolarizationand absorption factor (LPA) and also refraction correction (RC). Results showed that theinfluence of LPA correction is minor in XSA but the RC can significantly influence analysis. In the thesisthe issue of RC was considered and compared with approaches presented in the literature. In the thesistwo theoretical developments of the MGIXD method were presented: the procedure of c/a parameterdetermination and the influence of stacking faults on the results was taken into account. It was shown thatboth developments significantly improves the quality of experimental data analysis. In the present work theproblem of X-ray stress factors (XSF) used for the interpretation of XSA results was studied. Differenttheoretical grain elasto-plastic interaction models were considered and applied in XSA. Verification of theXSF was during tensile test for austenitic stainless steel and for the isotropic sample. Anisotropy of XSFwas also observed in: ground Ni alloy, polished austenitic stainless steel and CrN coating. The resultsshows that Reuss and free surface grain interaction models are in the best agreement with theexperimental results. Finally the MGIXD method was verified using synchrotron radiation and 3 differentwavelengths. The methodology was developed to treat data not only for different incident angles but alsousing simultaneously different wavelengths. Stresses vs. z – ‘real depth’ was calculated using the inverseLaplace transform applied to polynomial function. Wiliamson-Hall analysis was applied for collected data.Next multireflection method was applied for the energy dispersion diffraction measurements in which whitebeam containing radiation having different wavelengths was used (λ (Ǻ): 0.3–0.18/ E (keV): 40-68). Thestress analysis was performed using three different methods: standard sin2ψ method, Universal plotmethod and by using multireflection analysis. In the range of penetration depth to 0-15 μm theconvergence of the results obtained from different methods was gained. Moreover the synchrotron dataperfectly agree with the results obtained on laboratory diffractometer (Cu Kα radiation) close to the surface.For depth larger than 14 μm the experimental points exhibit significant spread and do not agree with theresults of standard method

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42

MARCISZKO, Marianna. "Diffraction study of mechanical properties and residual stresses resulting from surface processing of polycrystalline materials". Phd thesis, Ecole nationale supérieure d'arts et métiers - ENSAM, 2013. http://pastel.archives-ouvertes.fr/pastel-00992073.

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Methodology of stress measurements with multireflection grazing incidence method (MGIXD)was investigated and developed. The parallel beam geometry was applied. The incident beam in classicaldiffractometers was collimated by Göbel mirror and the tests of parallel configuration were performed for Alpowder. Results confirmed that both statistical error and the misalignment error can be reduced when theGöbel mirror is used. Physical factors were taken into account in XSA (X-ray stress analysis): Lorentzpolarizationand absorption factor (LPA) and also refraction correction (RC). Results showed that theinfluence of LPA correction is minor in XSA but the RC can significantly influence analysis. In the thesisthe issue of RC was considered and compared with approaches presented in the literature. In the thesistwo theoretical developments of the MGIXD method were presented: the procedure of c/a parameterdetermination and the influence of stacking faults on the results was taken into account. It was shown thatboth developments significantly improves the quality of experimental data analysis. In the present work theproblem of X-ray stress factors (XSF) used for the interpretation of XSA results was studied. Differenttheoretical grain elasto-plastic interaction models were considered and applied in XSA. Verification of theXSF was during tensile test for austenitic stainless steel and for the isotropic sample. Anisotropy of XSFwas also observed in: ground Ni alloy, polished austenitic stainless steel and CrN coating. The resultsshows that Reuss and free surface grain interaction models are in the best agreement with theexperimental results. Finally the MGIXD method was verified using synchrotron radiation and 3 differentwavelengths. The methodology was developed to treat data not only for different incident angles but alsousing simultaneously different wavelengths. Stresses vs. z - 'real depth' was calculated using the inverseLaplace transform applied to polynomial function. Wiliamson-Hall analysis was applied for collected data.Next multireflection method was applied for the energy dispersion diffraction measurements in which whitebeam containing radiation having different wavelengths was used (λ (Ǻ): 0.3-0.18/ E (keV): 40-68). Thestress analysis was performed using three different methods: standard sin2ψ method, Universal plotmethod and by using multireflection analysis. In the range of penetration depth to 0-15 μm theconvergence of the results obtained from different methods was gained. Moreover the synchrotron dataperfectly agree with the results obtained on laboratory diffractometer (Cu Kα radiation) close to the surface.For depth larger than 14 μm the experimental points exhibit significant spread and do not agree with theresults of standard method

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43

Glogowski, Elizabeth M. "Nanoparticle functionalization and grafting-from chemistry for controlling surface properties and nanocomposite behavior". Amherst, Mass. : University of Massachusetts Amherst, 2009. http://scholarworks.umass.edu/dissertations/AAI3349701/.

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44

Hudson, Guy Frederick, i Guy Frederick Hudson. "Surface chemistry of magnetic oxides and ferrites and their interaction with selected components of magnetic inks". Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184919.

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Studies to compare and elucidate some of the surface chemical characteristics of chromium dioxide and barium ferrite magnetic particles have been performed. These investigations primarily involved using the technique of flow microcalorimetry to look at the interaction of molecular probes (pyridine, 4-nitrophenol) and various components present in a magnetic ink (dispersants and model binder compounds) with the particles. The interactions were measured in terms of heats of adsorption and adsorption density. Ancillary experiments using FTIR and XPS were also performed. Both electrophoretic measurements and calorimetric studies showed that stabilized CrO₂ was less acidic than un-stabilized CrO₂. Similar measurements showed that un-doped barium ferrite was more acidic than Co and Ti doped barium ferrite. The interactions of dispersants and model binder components with barium ferrite were found to be very exothermic; heats of interaction of greater than -20 kcal/mole were not uncommon. Subsequent analysis of barium ferrite particles treated with dispersants and binder compounds using FTIR and XPS suggested that these compounds formed chemical complexes on the surface of the ferrite particles.

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45

CHASE, JENNIFER E. "SEMI-CONTINUOUS PLASMA POLYMERIZATION OF A FILM TO ENHANCE THE TEXTURE PROPERTIES OF AN ELASTOMER". University of Cincinnati / OhioLINK, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=ucin975349091.

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46

Åkerlund, Eva-Brita. "Composition, properties and surface structure of tribochemically deposited coatings". Thesis, Uppsala universitet, Tillämpad materialvetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-151881.

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Five tribochemically deposited coatings on honed cast iron cylinder liner segments has been studied with respect to surface properties, material composition, coating thickness, hardness and friction. Methods like Light Optical Microscopy (LOM), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), 3D topography using white light interferometry (VSI) and Electron Spectroscopy for Chemical Analysis (ESCA) were used to study the surface, coating thickness and material composition. Lubrication regimes (friction) were studied using a test set-up in a Lathe. An in-situ scratcher and nano indenter were used to study the hardness. It was found that the honing plateau surface is smoothened by the coating process while the honing scratches are kept more or less intact. The deposited coating thickness is approximately 10-100 nm. The coating is softer than the substrate and shows a butter-like behavior when scratched. Using only sulfur additive in the process fluid gives a smooth surface and an evenly distributed coating. Tungsten additive in the process fluid gives a thicker coating but a more irregular material distribution. Tungsten additive in the process fluid does not seem to stimulate the formation of WS2, but rather WO3 is formed.

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47

Wen, Chao. "Bounding Surface Approach to the Fatigue Modeling of Engineering Materials with Applications to Woven Fabric Composites and Concrete". Diss., North Dakota State University, 2011. https://hdl.handle.net/10365/28843.

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It has been known that the nucleation and growth of cracks and defects dominate the fatigue damage process in brittle or quasi-brittle materials, such as woven fabric composites and concrete. The behaviors of these materials under multiaxial tensile or compression fatigue loading conditions are quite complex, necessitating a unified approach based on principles of mechanics and thermodynamics that offers good predictive capabilities while maintaining simplicity for robust engineering calculations. A unified approach has been proposed in this dissertation to simulate the change of mechanical properties of the woven fabric composite and steel fiber reinforced concrete under uniaxial and biaxial fatigue loading. The boundary surface theory is used to describe the effect of biaxial fatigue loading. A fourth-order response tensor is used to reflect the high directionality of the damage development, and a second-order response tensor is used to describe the evolution of inelastic deformation due to damage. A direction function is used to capture the strength anisotropic property of the woven fabric composite. The comparisons between model prediction results and experimental data show the good prediction capability of models proposed in this dissertation.

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Wang, Xue. "Thermal Resistance Of Surface Modified, Dispersion Controlled CNT Foams". University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1460425184.

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Cheung, Big-chu Gloria. "An in vitro study of selected mechanical properties and surface profiles of some p̀osterior' composite resin restorative materials". Click to view the E-thesis via HKUTO, 1987. http://sunzi.lib.hku.hk/HKUTO/record/B38628259.

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張碧珠 i Big-chu Gloria Cheung. "An in vitro study of selected mechanical properties and surface profiles of some ��posterior' composite resin restorative materials". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1987. http://hub.hku.hk/bib/B38628259.

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