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Dissertations / Theses on the topic 'Surface formation'

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Published: 10 March 2023

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1

Viik, Rickard. "Surface layer formation on the surfaces of metallic lithium, copper and iron." Thesis, Uppsala universitet, Molekyl- och kondenserade materiens fysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-257571.

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2

Camps, Ameena Penelope. "Hydrate formation in near surface ocean sediments." Thesis, University of Leicester, 2008. http://hdl.handle.net/2381/30465.

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The aims of this research project were to assist in understanding hydrate formation, stability, and scientific aspects of CO2 storage as a liquid and CO2 hydrate. These have been addressed by two investigatory pathways: hydrate stability modelling and hydrate formation within sediments (in synthetic CO2 hydrates and natural methane hydrates). Developed computer models predict large regions offshore Western Europe with the potential to store considerable volumes of CO2 as a hydrate. Laboratory experiments have also shown CO2 hydrate to form rapidly and relatively easily in sandy sediments, cementing the sediment grains. In water-rich environments hydrate appears to create pore-filling cement impeding further CO2 flow to underlying sediments, which may aid trapping of an underlying liquid store. Fortunate acquisition of natural hydrate cores from Cascadia Margin also allowed investigation of natural methane hydrate formation; revealing a number of well-preserved methane hydrate morphologies, and complex brine filled pore networks within the hydrate, resulting from different rates of growth. Results highlight a number of research areas, which need addressing through further investigations. However, these preliminary investigations support CO2 storage as a hydrate as a potential feasible storage method, and this method should be pursued further as an emissions reducing mitigation strategy.
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3

Lee, Caroline Sunyong. "Surface layer formation on Pb/Sn alloys." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/11603.

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4

Ronda, Afonso Jose. "Railway formation condition assessment using seismic surface waves." Diss., University of Pretoria, 2016. http://hdl.handle.net/2263/66239.

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The demands of railway transport have been changing over the 150 years of existence of this type of transport in South Africa, specifically the performance requirements of the formation to cater for new traffic requirements. As such, it is important to assess the condition of this vital part of a railway track. This dissertation covers a research project conducted on two railway lines in which measurements of ground vibration were conducted in order to perform geophysical analysis and characterise the formation based on the results obtained. Measurements were taken on a 26 ton axle load track (Coal line, at Bloubank) and on a 20 ton axle load track (at Amandelbult) in South Africa. Planning and implementation of several test procedures to characterise track formation require considerable effort to minimize the impact on railway operations. Coupled with track occupation and the destructive nature of some of the test procedures, it is relevant to investigate alternative testing techniques to address the issues stated above. The use of surface waves for geotechnical characterization of sites is increasing worldwide. Applications to railway engineering have so far been limited to light load, high speed lines to minimize the use of poor geomaterials with reduced Rayleigh wave velocity. Four sites were identified where trains are operated at heavy loads, with the formation condition varying from poor to good. Seismic testing (geophysical) and conventional testing (deflection measurements) were performed at the identified sites. Seismic measurements were recorded using geophones as receivers, coupled to an amplifier and a computer. The source of the seismic events was the trains operating on the track and a hammer for impact testing. For the deflection measurements, the Remote Video Monitoring (RVM) technique was adopted. Dispersion analysis of the ground vibration experimental data was conducted using the multiple receiver method. The main conclusions reached with the analysis indicated that: __ Dispersion analysis had a good correlation with the formation deflection analysis; __ Phase velocity can be used as an indicator of the quality of a certain site; __ There are limitations when using trains as the energy source in terms of the generation of excitation frequency, which greatly reduces the phase velocity information in individual layers in the formation (i.e. wavelengths are not short enough).
Dissertation (MSc)--University of Pretoria, 2016.
Civil Engineering
MSc
Unrestricted
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5

Adler, Jeanette. "Film Formation and Surface Tension Studies of Powder Coatings." Thesis, KTH, Fibre and Polymer Technology, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3935.

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In industrial use of paint systems a swift processing is crucial. Another very important issue is to improve the quality of the final coating. This report investigates the film formation process of powder coatings, specially the spreading of individual powder particles. The obtained results can be used to understand and control the film formation process. In this way the desired levelling can be achieved and thus the desired gloss or other surface characteristics that may be required. This means that the method could be used when evaluating different polymer and additive combinations that could be used to change film formation behaviour or curing time for powder coating systems to suit various substrates. It makes it possible to avoid and minimize different surface defects as orange peel or cratering in the powder coated film.

We used a reflection optical microscope to better understand the film formation process and especially the spreading of a powder melt on surfaces with various surface energies. The obtained data were: the particle diameter, the area, area ratio and the contact angle of the powder particle as a function of time and temperature. This information can be used to derive the surface tension of any powder melt.

In this report we evaluate the dependencies of temperature, heat rate and surface energy for powder coatings on different substrates. The method provides information that can be used to optimize the film formation of a specific powder coating/substrate combination. This method can be used to evaluate the powder spreading and levelling on different substrates from a surface tension point of view.

We found, as expected, that the powder flows out on a hydrophilic surface and is inhibited by a hydrophobic. The increase of the area ratio on a hydrophilic surface was about five times as the initial area coverage and on a hydrophobic surface only two times the initial area coverage. The contact angle between the melted powder particle on the different surface types could be calculated. The melt surface tension could be calculated since three substrates surfaces with various surface energies were used. The melt surface tension was found to be about 18.5 mN/m.


Sammanfattning

Vid industriell användning av ett färgsystem är det viktigt med en snabb och smidig målningsprocess. En viktig del är att förbättra kvaliteten på den färdiga ytan. Denna rapport undersöker filmbildningsprocessen för pulverfärg, närmare bestämt spridningen av individuella pulverpartiklar. Resultaten från utvärderingen av denna metod kan användas för att bättre förstå och få kontroll över filmbildningsprocessen. Med denna undersökningsmetod kan den önskade utslätningen uppnås och därmed den önskade glansen eller annan yteffekt som kan vara önskvärd.

Metoden kan användas för att utvärdera olika polymer- och additivkombinationer som kan användas för att ändra filmbildningens uppförande eller bestämma härdningstiden för en pulverfärg att passa ett visst substrat. Metoden gör det möjligt att förhindra och minska olika ytdefekter såsom apelsinskals- eller kratereffekter i pulverfärgens yta.

Ett optiskt reflectionsmikroskop användes för att bättre kunna förstå filmbildningsprocessen och särskilt spridningen av smält pulver på substrat med olika ytenergier. De mätdata vi fick var partikeldiameter, area, areaförändring och kontaktvinkeln för pulverpartiklar som funktion av tid och temperatur. Ur denna information kunde pulversmältans ytenergier härledas.

I denna rapport utvärderas pulvrets beroende av temperatur, uppvärmning och ytenergi på olika substrat. Denna metod ger information som kan användas för att optimera filmbildningen av en specifik kombination av pulverfärg och substrat. Denna metod kan också användas för att utvärdera pulverspridning och utjämning av färgfilmen på olika substrat med avseende på ytenergierna.

Som förväntat flyter pulvret ut på hydrofila ytor och utflytningen ändras på en hydrofob yta. På en hydrofil yta sprider sig partikeln till fem gånger den ursprungliga arean över substratet och motsvarande två gånger för en hydrofob yta. Kontaktvinkeln mellan en smält pulverpartikel på olika sorters substrat från utförda mätningar beräknas utifrån utförda mätningar. Kontaktvinklar mellan pulver och olika substrat kan användas för att beräkna smältans ytspänning. Smältans ytspänning kan beräknas då experiment gjorts på tre sorters ytor med olika kända ytenergier. Smältans ytspänning var 18,5 mN/m.

Slutsatsen är att det går att observera och utvärdera resultaten av utsmältningsförloppet för pulverfärg med denna metod.

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6

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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7

Todorovi´c-Marini´c, Dragana. "Pattern formation during electrohydrodynamic convection with a free surface." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq20856.pdf.

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8

Oswald, Robert [Verfasser]. "Formation and surface exchange of nitrous acid / Robert Oswald." Mainz : Universitätsbibliothek Mainz, 2014. http://d-nb.info/1049968956/34.

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9

Wang, Zhi. "Mineral scale formation-aspects of surface energy and adhesion." Thesis, University of Leeds, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434828.

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10

Farnham, Taylor A. "Hydrate formation and adhesion on low surface energy materials." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104142.

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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 43-44).
Clathrate hydrates are ice-like solid substances that often form inside oil and gas pipelines and are responsible for flow blockages, sometimes leading to catastrophic disasters. Minimizing hydrate adhesion and accumulation of solids on pipelines can effectively address this problem. In this thesis, we reduce the adhesion of cyclopentane hydrates by promoting the formation of a cyclopentane barrier film between the hydrate and the solid surface. The presence of this liquid film depends on the spreading coefficient of cyclopentane on the solid in the presence of water. Through a systematic modification of the surface chemistry of the solid surface using two different silanes, we correlate the wettability of water and cyclopentane to the adhesion of cyclopentane hydrates. We demonstrate negligible hydrate formation and adhesion on octadecyltrichlorosilane-coated surfaces via macroscopic visualization, surface tilt and adhesion measurements. The use of the spreading coefficient as a design parameter could further advance the development of effective, passive, hydrate-repelling surfaces.
by Taylor A. Farnham.
S.M.
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11

Kim, Ji Hoon. "The star formation history of low surface brightness galaxies." College Park, Md.: University of Maryland, 2007. http://hdl.handle.net/1903/7646.

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Thesis (Ph. D.) -- University of Maryland, College Park, 2007.
Thesis research directed by: Dept. of Astronomy. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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12

Gaceb, Mohamed. "An investigation of microcrack formation on machined surfaces." Thesis, Sheffield Hallam University, 1985. http://shura.shu.ac.uk/20604/.

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In recent times a number of workers have pointed out the importance of microcrack formation to the machining process and to surface integrity requirements of machined components. Microcracks have been identified within the shear zone and their presence used to explain some aspects of the chip formation process. It is clear that microcracks represent a major feature in the shear zone in machining, particularily when the workpiece is a two-phase material. The presence of microcracks in the machined surface was reported some fifteen years ago and confirmed recently. A preliminary study carried out on a number of materials machined under various cutting conditions has indicated that microcracks are produced in machined surfaces as a result of machining. However, to the present time there has been no systematic study of the formation of microcracks in the machined surface, and their extent, dimensions, and the conditions under which they are produced are completely unknown. In so far as microcracks may affect the fatigue, corrosion and other properties of the machined surface, it is important that a method of quantifying microcrack formation should be found. A feasibility study has been carried out which has led to the use of the transmission electron microscope as a tool to quantify microcrack formation in the machined surface. A technique based on transmission electron microscopy is described in the present thesis along with its application. Two new parameters, the microcrack area ratio "Ma" and the microcrack density "Md" are introduced and defined. The extent of microcrack formation in the machined surface is studied as a result of varying: (i)- cutting speed, (ii)- undeformed chip thickness, (iii)- rake angle, (iv)- workpiece hardness. The results are discussed and conclusions drawn. Finally, a number of suggestions for future work are formulated which mark the start of a whole new area of research in surface microcracking.
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13

Buhaug, Øyvind. "Deposit Formation on Cylinder Liner Surface in medium-speed Engines." Doctoral thesis, Norwegian University of Science and Technology, Faculty of Engineering Science and Technology, 2003. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-209.

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The presence of deposits in the honing grooves in diesel engine cylinder liners can cause a severe increase in the consumption of lubricating oil. These deposits may appear amber in which case they may be referred to as 'liner lacquerer' or be nearly invisible in which case they are often referred to as 'transparent glaze' or 'bore glaze' in the marine sector. The formation of these deposits is believed to be influenced by engine design, engine load, fuel composition and lubricating oil composition. This relationship has, however, not been well understood and little material has been published on this subject. This thesis describes an investigation of this phenomenon. The problem has been approached by studying the composition of deposit samples, studying cases of deposit formation in the field and through experimental work.

As a result of this work, it is hypothesized that the root cause of the deposit formation is a mismatch between the rate of formation of oil insoluble material on or within the oil film and the oil film dispersing power and exchange rate. A large number of parameters will affect this balance which explains the sliding shift in appearance and composition of 'liner lacquer' and 'bore glaze' and the difficulty in identifying the cause of this problem.

A combined mass balance and chemical kinetics approach is used to bridge the gap between fundamental deposit theory and tangible engine related parameters. It is thus possible to rationalize the formation of deposits on cylinder liners. This understanding is sufficient to point out which factors should be considered in terms of the prevention of deposit formation and to present a viable hypothesis on the reason for the deposit formation in the engines that have been investigated in the course of this work as summarized in the following paragraph.

The presence of deposit indicates that the dispersing power and transport rate of the oil film is insufficient to deal with the deposit precursors being formed. This is believed related to extensive low load operation which is associated with both low liner temperatures and low nominal oil consumption in these engines. Low liner temperatures will encourage the formation of insoluble material due to condensation of sulphuric acid precursors, while low oil consumption is believed to indicate low oil film exchange which reduces the transport of matter and also contributes to oil film oxidation by prolonging the exposure to combustion gases.

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14

Murray, Raquel. "Effects of surface roughness on bloodstain spreading and spine formation." Thesis, Cranfield University, 2016. http://dspace.lib.cranfield.ac.uk/handle/1826/10368.

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Expert witnesses employ bloodstain pattern analysis (BPA), to provide objective analysis of bloodstain evidence in criminal cases. This thesis added to the scientific understanding of BPA by generating and analysing a large data set of 785 horse blood experiments. The experiments produced impact velocities, u0, of 2:89ms-1 to 6:54ms-1, with impact angles, [theta]f , 90°, 72°, 54°, 36°, and 18°. Different surface roughnesses were investigated: conditioned and unconditioned paper, smooth steel, and three roughened steel substrates with roughness values, Ra, 1:6x10-6 m, 3:2x10-6m, and 6:3x10-6 m. To analyse the data, two computational tools were developed. The first tool extracted the diameter and velocity of a droplet from high-speed videos. The second tool measured stain properties and counted spines of stains resulting from 90° and 72°. The results of these experiments are investigated, extracting relationships between impact properties of droplets to stain properties. Each of the stain properties were related to some combination of a non-dimensional number (Bond number, Bo, Froude number, Fr, or Reynolds number, Re) and impact angle. It was found that the stain area and stain perimeter are proportional to Bo(sin[theta]f )-1. The numberof spines and/or tails on a stain is dependent on Fr(sin[theta]f )2. The major diameter is proportional to Re(sin[theta]f )2 and conversely the minor diameter is proportional to Re(sin[theta]f)2. The full length of the stain is proportional to Bo(sin[theta]f)-2. The results showed that increased surface roughness, promotes increased variability in the bloodstains, up to a limit of Ra = 6:3x10-6m. The roughest steel is statistically the same as paper in almost all stain properties. The results proved a need to account for surface roughness in modelling the spreading of a droplet on a substrate. Starting from the laws of conservation of energy, a new model for predicting spread factor was derived which accounts for the impact angle and substrate roughness. This model uses a coefficient based on properties from the stain and is able to predict the experimental spread factors in this thesis more accurately than the spread factor models in literature. Two new equations were derived that calculate the impact velocity and droplet diameter using only stain properties, not experimental fitting constants, making the expressions more robust.
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15

Alves, Verdasca José A. "Pattern formation in surface reactions :the role of nonlinear diffusion." Doctoral thesis, Universite Libre de Bruxelles, 2000. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211803.

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16

Alhazmi, Muflih. "Exploring mechanisms for pattern formation through coupled bulk-surface PDEs." Thesis, University of Sussex, 2018. http://sro.sussex.ac.uk/id/eprint/78232/.

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This work explores mechanisms for pattern formation through coupled bulksurface partial differential equations of reaction-diffusion type. Reaction-diffusion systems posed both in the bulk and on the surface on stationary volumes are coupled through linear Robin-type boundary conditions. In this framework we study three different systems as follows (i) non-linear reactions in the bulk and surface respectively, (ii) non-linear reactions in the bulk and linear reactions on the surface and (iii) linear reactions in the bulk and non-linear reactions on the surface. In all cases, the systems are non-dimensionalised and rigorous linear stability analysis is carried out to determine the necessary and sufficient conditions for pattern formation. Appropriate parameter spaces are generated from which model parameters are selected. To exhibit pattern formation, a coupled bulk-surface finite element method is developed and implemented. We implement the numerical algorithm by using an open source software package known as deal.II and show computational results on spherical and cuboid domains. Theoretical predictions of the linear stability analysis are verified and supported by numerical simulations. The results show that non-linear reactions in the bulk and surface generate patterns everywhere, while non-linear reactions in the bulk and linear reactions on the surface generate patterns in the bulk and on the surface with a pattern-less thin boundary layer. However, linear reactions in the bulk do not generate patterns on the surface even when the surface reactions are non-linear. The generality, robustness and applicability of our theoretical computational framework for coupled system of bulk-surface reaction-diffusion equations set premises to study experimentally driven models where coupling of bulk and surface chemical species is prevalent. Examples of such applications include cell motility, pattern formation in developmental biology, material science and cancer biology.
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17

Lin, Leigh. "Controlling CRUD vapor chimney formation in LWRs through surface modification." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/95594.

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Thesis: S.M., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2014.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 105-112).
Fouling has been a persistent problem for fluid-solid interfaces, varying from heat exchangers to ship hulls. In nuclear power plants, buildup of CRUD can accelerate corrosion, increase pressure drops, cause axial power shifts, and increase radiation dose to workers. In this experiment, we studied the effect of induced microcavity and micropost patterns on CRUD morphology at atmospheric pressure. Samples with various pitches of microcavities and microposts were boiled in simulated PWR coolant. The effect of heat flux on CRUD formation was also examined. The experiments support previous theories that subcooled nucleate boiling is enhanced at microcavities, and that CRUD deposition is promoted at those sites. A thin ring of particles, less than a micrometer in width, was seen around most microcavities even when the surrounding areas were crudded. However, some of the samples with microcavity pitches 50 pm and smaller experienced a pattern of clean and crudded areas, with the region around the microcavities free of CRUD more often than not. A theory is put forth that this is caused by interfering forces due to bubbles collapsing. The micropost samples showed substantial CRUD growth, particularly for the sample subjected to a high heat flux. The results of this experiment could have major implications for development of a self-cleaning material for heated surfaces.
by Leigh Lin.
S.M.
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18

Akizuki, Makoto. "Gas Cluster Ion-Solid Surface Interaction and Thin Film Formation." Kyoto University, 1999. http://hdl.handle.net/2433/181783.

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19

Pickering, Timothy Edward 1970. "Kinematics and star formation properties of low surface brightness galaxies." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282756.

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We present detailed studies of the kinematics and star formation properties of low surface brightness (LSB) galaxies. A total of five giant LSB galaxies including the prototype, Malin 1, were imaged in the 21-cm line of H sc I to provide the first glimpse into the kinematics of these systems. We find that these are some of the first examples to be uncovered of galaxies that are both massive and dark matter dominated. We also find that most of the galaxies have gas surface densities that lie below the critical density for star formation at all radii, consistent with their lack of star formation. In a couple of cases, though, the gas exceeds the critical density where there is no star formation implying a higher gas velocity dispersion or strong flaring of the gas disk. Long-slit optical spectroscopy and broadband CCD imaging are presented for a total of 71 LSB galaxies. We find that these galaxies follow a Fisher-Tully relation with a slope that is in good agreement with the slopes found for other samples of LSB and HSB galaxies. We interpret both the optical and H sc I rotation curves in terms of mass models consisting of a halo only or a stellar component plus a halo of either an isothermal form or an NFW halo of the form described by Navarro et al. (1996) and find that the rotation curves are generally best modeled by low mass-to-light ratio stellar components. By modeling the rotation curves with only an NFW halo and comparing the results with the predictions of cosmological simulations we find that these data are marginally consistent at best with Standard Cold Dark Matter and generally favor lower density models. However, we also find that when including the stellar component, the NFW halo gives a significantly worse fit than an isothermal halo in many cases. This suggests that the inner parts of galactic halos may not be well described by the NFW halo profile.
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20

Teixeira, Miguel Angelo Cortez. "Interaction of turbulence with a free surface." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340045.

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21

Steel, James. "Surface photometry of early-type galaxies in rich clusters." Thesis, Durham University, 1998. http://etheses.dur.ac.uk/4868/.

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This thesis investigates the morphology of early-type galaxies in two rich clusters using 2D surface photometry. In particular, the amount of light in the 'disk' component is focussed upon, as the presence of a disk is the main morphological criterion in distinguishing between the traditional 'elliptical' and 'S0' classes. Extensive and photometric E-band CCD observations of continuous areas of the Coma and Abell 1367 clusters were obtained at the 2.5 m Isaac Newton telescope, La Palma during March 1994. A subset of this large data-set has been used in this study, comprising a magnitude-limited (to R = 15.6) sample of 153 galaxies in the two clusters. Surface photometry measurements, including surface brightness profiles and isophotal shapes, have been made for the sample. Atmospheric seeing is a major problem when measuring light profiles at the distance of Coma from ground-based telescopes. Typical seeing at La Palma (FWHM~1.2") is a significant fraction of the effective radius of many Coma/Abell 1367 galaxies (r(_e)~3" for small ellipticals). An iterative algorithm was developed to deconvolve the effects of seeing from surface brightness profiles. The result of the algorithm is to extend the range of useful surface photometry inwards to within 2 times the FWHM. In order to parametrise the surface brightness profiles and discriminate between different profile-types, further software was developed to fit one- and two-component model profiles to the seeing-corrected data. The following parameters were measured and tabulated for each of the 153 galaxies: total magnitude M(_t); half-light parameters r (_1/2) and (μ)(_1/2); SB at half-light radius μ(r(_1/2)); photometric diameter D(_19.23) (equivalent to D(_n)); ellipticity at R = 21.5 isophote ϵ(_21.5); averaged isophote high-order terms (C(_3)), (S(_3)), (C(_4)) and (S(_4)); effective radii and surface brightnesses of 5 single power-law r(^1)(_n) models, r"e and (^)"^ (n = 1,2,3,4,5); best-fitting power-law index n; bulge effective radii and surface brightnesses from the two-component fit and (/^)\; disk effective parameters r'^e and {nY^] and disk-to-bulge luminosity ratio DjB. The measured parameters have been used to investigate various aspects of early-type galaxy morphology. The conclusions are outlined below. Firstly, a two-component r? plus exponential model is a better fit to most galaxies than a single component law fit. Secondly, the traditional division of early-type galaxies into 'elliptical' and 'SO' classes is severely biased by the viewing angle. In fact, it appears that early-type galaxies comprise a population of objects with smoothly varying bulge-to-disk ratio - although a few ellipticals (less than 13%) do not appear to have a exponential component. Finally, there is a general correlation (with much scatter) between the size and the profile shapes of early-type galaxies. The interpretation is that smaller galaxies are more disk-dominated than larger galaxies, which can be linked to the merging process in rich clusters.
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22

Mesgar, Mostafa [Verfasser]. "Multi-scale modeling of island formation and surface dynamics on the Au(100) surface / Mostafa Mesgar." Ulm : Universität Ulm. Fakultät für Naturwissenschaften, 2015. http://d-nb.info/1075253683/34.

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23

Gumbs, Vernice Pamela. "THE RELIABILITY OF SURFACE ASSEMBLAGES IN ARCHAEOLOGICAL INTERPRETATION." University of Cincinnati / OhioLINK, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=ucin975606147.

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24

Evteev, Alexander V., Elena V. Levchenko, Irina V. Belova, and Graeme E. Murch. "Formation of a surface–sandwich structure in Pd-Ni nanoparticles by interdiffusion: Formation of a surface–sandwich structure in Pd-Ni nanoparticlesby interdiffusion: atomistic modelling." Diffusion fundamentals 6 (2007) 18, S. 1-2, 2007. https://ul.qucosa.de/id/qucosa%3A14192.

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25

Rathman, James Flinn. "A study of the thermodynamics of micelle formation in binary surfactant mixtures /." Full-text version available from OU Domain via ProQuest Digital Dissertations, 1987.

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26

Nielsen, Jon-Fredrik. "Energetically and kinetically driven step formation and evolution on Silicon surfaces /." The Ohio State University, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=osu1486402957194989.

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27

Ameripour, Sharareh. "Prediction of gas-hydrate formation conditions in production and surface facilities." Texas A&M University, 2005. http://hdl.handle.net/1969.1/4220.

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Gas hydrates are a well-known problem in the oil and gas industry and cost millions of dollars in production and transmission pipelines. To prevent this problem, it is important to predict the temperature and pressure under which gas hydrates will form. Of the thermodynamic models in the literature, only a couple can predict the hydrate-formation temperature or pressure for complex systems including inhibitors. I developed two simple correlations for calculating the hydrate-formation pressure or temperature for single components or gas mixtures. These correlations are based on over 1,100 published data points of gas-hydrate formation temperatures and pressures with and without inhibitors. The data include samples ranging from pure-hydrate formers such as methane, ethane, propane, carbon dioxide and hydrogen sulfide to binary, ternary, and natural gas mixtures. I used the Statistical Analysis Software (SAS) to find the best correlations among variables such as specific gravity and pseudoreduced pressure and temperature of gas mixtures, vapor pressure and liquid viscosity of water, and concentrations of electrolytes and thermodynamic inhibitors. These correlations are applicable to temperatures up to 90ºF and pressures up to 12,000 psi. I tested the capability of the correlations for aqueous solutions containing electrolytes such as sodium, potassium, and calcium chlorides less than 20 wt% and inhibitors such as methanol less than 20 wt%, ethylene glycol, triethylene glycol, and glycerol less than 40 wt%. The results show an average absolute percentage deviation of 15.93 in pressure and an average absolute temperature difference of 2.97ºF. Portability and simplicity are other advantages of these correlations since they are applicable even with a simple calculator. The results are in excellent agreement with the experimental data in most cases and even better than the results from commercial simulators in some cases. These correlations provide guidelines to help users forecast gas-hydrate forming conditions for most systems of hydrate formers with and without inhibitors and to design remediation schemes such as: · Increasing the operating temperature by insulating the pipelines or applying heat. · Decreasing the operating pressure when possible. · Adding a required amount of appropriate inhibitor to reduce the hydrateformation temperature and/or increase the hydrate-formation pressure.
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28

Farajollahi, Farid [Verfasser]. "Formation of self-assembled microstructure on the polymer surface / Farid Farajollahi." Ulm : Universität Ulm. Fakultät für Naturwissenschaften, 2016. http://d-nb.info/1084767732/34.

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29

Huang, Zhoushen. "Spontaneous formation of charge inhomogeneity on silica surface immersed in water /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?PHYS%202007%20HUANG.

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30

Wollschläger, Daniel. "Dynamic surface completion the joint formation of color, texture, and shape /." [S.l.] : [s.n.], 2006. http://e-diss.uni-kiel.de/diss_1637/d1637.pdf.

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31

Sun, Wei. "EVAPORATION-INDUCED FORMATION OF WELL-ORDERED SURFACE PATTERNS ON POLYMER FILMS." UKnowledge, 2015. http://uknowledge.uky.edu/cme_etds/54.

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Various techniques of fabricating surface patterns of small scales have been widely studied due to the potential applications of surface patterns in a variety of areas. It is a challenge to fabricate well-ordered surface area efficiently and economically. Evaporation-induced surface patterning is a promising approach to fabricate well-ordered surface patterns over a large area at low cost. In this study, the evaporation-induced surface patterns with controllable geometrical characteristics have been constructed. The dewetting kinetics on deformable substrate is also investigated. Using simple templates to control the geometry and the evaporation behavior of a droplet of volatile solvent, various gradient surface patterns, such as concentric rings, multiple straight stripes formed with a straight copper wire, etc. have been constructed on PMMA films. The wavelength and amplitude are found to decreases with the decrease of the distance to the objects used in templates. There is also a nearly linear relation between the amplitude and wavelength. The effects of several experimental parameters on the geometrical characteristics of the surface structures are studied, i.e. dimensions of the template, film thickness (solution concentration), substrate temperature, etc. The wavelength and amplitude increase with the increase of the film thickness (solution concentration), with the increase of the dimension of the template. However with the increase of the substrate temperature, the wavelength increases, while the amplitude decrease. Hexagonal network in pre-cast PMMA film have been fabricated by a “breath figure” approach at low humidity and low substrate temperature. The dimensions of the hexagonal holes are dependent on the template size and film thickness. The kinetics of the evaporative dewetting of a liquid (toluene) film on a deformable substrate (PMMA film) with the confinement of a circular copper ring is also studied. The liquid film first dewets from the outside towards the copper ring. When a critical volume is reached, an internal contact line appears, which dewets from the center to the copper ring smoothly with a constant velocity, then switches to a “stick-slip” motion. The average velocity of the smooth motion increases with the increase of the copper ring size and film thickness.
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32

Liu, Y. "Path planning algorithms for unmanned surface vehicle formation in maritime environment." Thesis, University College London (University of London), 2016. http://discovery.ucl.ac.uk/1501049/.

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The research into unmanned surface vehicles (USVs) has received increasing attention in recent years due to the maturity of the technology. Potential deployments of USVs can been seen through both civilian and military applications with the benefits of improved mission efficiency and decreased resource costs. However, it should be noted that current USV platforms are generally of small size with low payload capacity and short endurance. To improve the effectiveness, there is a trend to deploy multiple USVs as a formation fleet. This thesis therefore primarily investigates the path planning problem of USV formation. Overall, algorithms have been developed based on the leader-follower control strategy and adopt the fast marching method (FMM) as the base algorithm. To make the algorithm more suitable for practical maritime navigation, the FMM has been first improved and redeveloped by considering the dynamic characteristics of the USV and making the generated path compliant with the USV's turning constraints. Next, to solve the problem of avoiding moving obstacles in the environment, a constraint fast marching method (CFMM) has been proposed to model the dynamic behaviour of moving ships. The CFMM generates effective ship domain and collision avoidance areas of moving ships according to different velocities so protecting the USV formation from collision. The uncertainties associated with the maritime environment have also been investigated, and a Kalman filter based trajectory tracking algorithm (KFTTA) has been designed and developed to obtain the accurate navigation information of moving ships. The KFTTA can be integrated with the formation path planning algorithm to improve its effectiveness and efficiency. All algorithms have been tested and verified using computer based simulations. In addition, full scale experiments on a practical USV have also been carried out to test capability in water.
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33

Mikolutskiy, S. I., V. A. Yamschikov, V. Yu Khomich, and V. A. Shmakov. "Model of Nanostructure Formation on Solid Surface Melted by Laser Pulse." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/35417.

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The paper describes the model of nanostructure formation on solid surface by nanosecond laser pulses melting the material. Stefan problem with corresponding boundary conditions is solved in combination with nucleation theory. It is found that typical size of surface nanostructure formed depends on energy and duration of laser pulse. For comparison of theoretic and experimental results titan pieces irradiated by ArF-laser are shown. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35417
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34

Smith, Maureen McBride. "Modeling trihalomethane formation in bromide-containing surface water undergoing conventional treatment." CSUSB ScholarWorks, 1993. https://scholarworks.lib.csusb.edu/etd-project/638.

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35

Cooperstein, Michael Stephen. "The effects of slope aspect on the formation of surface hoar and diurnally recrystalized near-surface faceted crystals." Thesis, Montana State University, 2008. http://etd.lib.montana.edu/etd/2008/cooperstein/CoopersteinM0508.pdf.

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This research was conducted to determine if slope aspect played a role in the formation, size and shape of surface hoar and near-surface faceted crystals and on the meteorological variables that are known to result in the formation of these two weak layers. No studies have specifically studied the effects of slope aspect on the size and shape of these crystals nor the effects of slope aspect on the meteorological variables which are known to result in differences in temperature and vapor pressure gradients and ultimately result in the formation of two weak layers.
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36

Furbank, Roy Jeffrey. "Drop formation from particulate suspensions." Diss., Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-05172004-100527/unrestricted/furbank%5Froy%5Fj%5F200407%5Fphd.pdf.

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Thesis (Ph. D.)--School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 2005. Directed by F. Joseph Schork.
Schork, F. Joseph, Committee Chair ; Morris, Jeffrey F., Committee Co-Chair ; Forney, Larry J., Committee Member ; Breedveld, Victor, Committee Member ; Mucha, Peter J., Committee Member ; Smith, Marc K., Committee Member. Includes bibliographical references.
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37

Reffet, Erwan. "Interaction Surface-Atmosphère en Planétologie Comparée : Application à la formation des dunes." Phd thesis, Université Paris-Diderot - Paris VII, 2010. http://tel.archives-ouvertes.fr/tel-00656378.

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Dans ce manuscrit, nous nous intéressons aux interactions entre surface et atmosphère et plus spécifiquement à la formation de dunes dans le Système Solaire. Pour mener notre étude, nous procédons à des expériences en laboratoire qui reproduisent des dunes à l'échelle réduite et de manière contrôlée. Ces expériences sont accompagnées d'une étude par modélisation numérique. Ces deux outils nous permettent d'étudier la formation des dunes mais également d'en suivre l'évolution. En utilisant des régimes bimodaux et symétriques de vents, nous mettons en évidence la formation de champs de dunes transverses et de champs de dunes longitudinales pour de faibles et grandes séparations angulaires respectivement. Notre étude montre que la transition entre ces deux domaines se situe proche d'un angle de 90° mais dépend de la période choisie pour le régime de vents par rapport au temps caractéristique d'adaptation des structures. Cette transition est décalée vers les faibles séparations angulaires pour les courtes périodes et s'accompagne d'un mûrissement plus rapide des structures longitudinales. L'étude sur les champs de dunes est approfondie par un travail sur les dunes isolées qui souligne la différence de stabilité des dunes transverses et longitudinales à long terme. Les premières deviennent instables et se cassent en barchanes (ou barchanoïıdes) lorsque l'apport de sable, ou la quantité de sable mobilisable, est trop faible alors que les dunes longitudinales restent stables. Sous ces régimes bimodaux de vents, l'évolution d'un tas de sable aboutit à une grande diversité de morphologies. Des barchanoïdes, dont l'aspect évolue avec l'augmentation de l'angle entre les vents, sont formées pour de faibles séparations angulaires. Pour un angle de 90° une dune en forme de "châtaigne" est modelée et une extension longitudinale se développe pour des angles plus importants soulignant le côté attracteur de la structure longitudinale pour ce domaine de régimes de vents. Enfin, nos résultats permettent d'utiliser les dunes pour contraindre les régimes de vents lorsque des mesures directes ne sont pas possibles. Ainsi, elles représentent une contrainte à l'échelle globale sur Titan et nous donnent des informations locales à la surface de Mars.
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38

Wesley, Daniel. "The role of surface wettability on bubble formation in air-water systems." Thesis, University of Sheffield, 2015. http://etheses.whiterose.ac.uk/13482/.

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The production of microbubbles is rapidly becoming of considerable global importance with many industries taking advantage of the increased mass transfer rates the bubbles can attain. Many factors have interrelated roles during bubble formation, with effects such as gas flow rate, liquid viscosity, pore size and pore orientation all imparting considerable influence during the formation process. Many of these features have been examined in detail and are relatively well understood. However, the role of surface wettability and the interactions at the gas-liquid-solid triple interface have for the most part been neglected, and it is the role of this wettability that is examined herein. Utilising the well-studied wet chemistry surface modification techniques of silanes and thiols, many substrates have been modified and the wettability tested. Contact angle goniometry has been utilised to assess the wetting characteristics of each substrate, and the role of surface roughness has been discussed in relation to both the static Young’s contact angle and the advancing and receding angles. Modified porous plates have been used to generate bubbles, with controlled single pore, multiple controlled pore, and multiple randomised pore systems being investigated. A steady flow of air was bubbled into distilled water through the various diffuser plates. It has been observed a contact angle of 90° is of vital importance, with a significant increase of bubble size above the 90° angle, defined as the hydrophobic wetting region. On the contrary, bubble size is greatly reduced below this angle, in the region defined as the hydrophilic region. The effect is seen to increase as the density of pores increases when the plate from which they are emitted is relatively smooth. Upon roughening, the effect is seen to diminish, and mechanisms for this process have been postulated. It is thought that the surface topography disrupts the modifying layers and also physically restricts the growing bubble, preventing the growth of the bubbles emitted from a hydrophobic surface. Attempts have been made to support this hypothesis both qualitatively and quantitatively. The fluidic oscillator of Zimmerman and Tesar has been examined, with numerous physical features being investigated. The oscillator was then added to the system to investigate the effect of wettability under substantial oscillation. It has been shown that the bubble size emitted from hydrophobic surfaces is significantly reduced when compared to the steady flow system. The effect is believed to be due to the ‘suction’ component of the oscillatory flow created by the oscillator. It has been seen via high speed photography that the growth rate of the growing bubble slows significantly as the flow begins to switch, before a reduction in size is seen as the gas is removed from the bubble. The opposing forces of buoyancy and suction act to elongate the bubble neck causing break off at a significantly reduced size. Although the diffuser plate is often observed to oscillate like the skin of a drum, this is not the predominant cause of the size reduction. Further experiments have been conducted using a synthetic actuator jet to create a pulsed air flow with only a positive component. Bubble size is not affected in this case, despite frequency sweeps being employed.
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39

Kishawy, Hossam Eldeen A. "Chip formation and surface integrity in high speed machining of hardened steel /." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0003/NQ42858.pdf.

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40

Danhorn, Thomas. "Agrobacterium tumefaciens biofilm formation polar surface attachment and response to phosphorus starvation /." [Bloomington, Ind.] : Indiana University, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3277983.

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Thesis (Ph.D.)--Indiana University, Dept. of Biology, 2007.
Source: Dissertation Abstracts International, Volume: 68-09, Section: B, page: 5720. Adviser: Clay Fuqua. Title from dissertation home page (viewed May 9, 2008).
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41

Chu, Hiu-ping, and 諸曉平. "Trihalomethane formation in contaminated surface water and its controlby membrane bio-reactor." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B29744052.

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42

Taquet, Vianney. "Chimie à la surface des grains dans les régions de formation stellaire." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00790641.

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Les premières étapes de la formation stellaire sont accompagnées d'une évolution de la chimie, à partir de molécules simples dans les nuages froids et sombres vers la détection de molécules organiques complexes autour des étoiles de Classe 0. Bien que principalement composés de gaz, ces nuages contiennent également une petite quantité de poussière microscopique. La contribution de cette poussière est toutefois importante car elle agit comme un catalyseur pour la formation de molécules clés observées dans les glaces froides interstellaires, telles que l'eau ou le méthanol. Ces glaces seraient la première étape d'une chimie riche observée dans les enveloppes tièdes des protoétoiles. Durant cette thèse, je me suis concentré sur la première étape en utilisant une double approche. i) Modélisation. J'ai développé un modèle astrochimique couplant la chimie en phase gazeuse et à la surface des grains. Ce modèle suit la formation multicouche des glaces interstellaires et, grace à une approche multiparamètre, nous permet également d'étudier l'influence de paramètres physiques, chimiques, et de surface, tels que la porosité des grains, sur la composition chimique des glaces. Le modèle a ensuite été utilisé pour prédire la différenciation chimique et la deutéra- tion des glaces interstellaires. Ainsi, j'ai construit un réseau chimique en prenant en compte les travaux expérimentaux et théoriques les plus récents. J'ai ensuite appliqué ce modèle à différents cas. J'ai par exemple montré que les glaces sont très hétérogènes et que leurs compositions sont très sensibles aux conditions physiques ainsi qu'à différents paramètres de surface. La deutéra- tion élevée du formaldehyde et du méthanol a été prédite pour une phase dense (nH ∼ 5 × 10^6 cm−3) et rapide (∼ 5000 ans) tandis que la deutération plus faible de l'eau est prédite pour des conditions typiques de nuages moléculaires. La deutération est très sensible et peut donc etre utilisée comme un traceur des conditions physiques. ii) Observations. J'ai été impliqué dans différents projets observationnels dont les buts étaient reliés aux problèmes de la chimie à la surface des grains. J'ai obtenu les trois résultats suivants. Nous avons montré une évolution de la deutération sélective du méthanol avec le type de la protoétoile, le rapport d'abondance [CH2DOH]/[CH3OD] diminuant avec la masse de la protoé- toile. Une cartographie interféromètrique de l'eau deutérée vers deux protoétoiles de faible masse nous a permis de contraindre un fort degré de deutération de l'eau dans de nouvelles sources. Finalement, nous avons détecté pour la première fois plusieurs molécules organiques complexes dans un coeur prestellaire, remettant en question le scénario actuel de formation des molécules organiques complexes dans des conditions tièdes.
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43

Hsiao, Wen Kai 1972. "Effects of surface properties on solder bump formation by direct droplet deposition." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/27100.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.
Includes bibliographical references (leaves 158-162).
Recent advances in microdroplet generation and deposition processes have made it possible to directly form solder bumps on integrated circuits using micron-sized molten metal droplets. The direct droplet deposition bumping process can potentially produce uniform-sized bumps more economically than the existing processes such as plating and stencil printing. However, the development of this new bumping method is still in its infancy, particularly because of a lack of understanding about the post-impact deposition behavior of molten droplets on solid targets. A deposited molten on the deposition efficiency, as well as on the final bump size and shape. The present study investigates the effects of wetting and surface roughness on droplet bouncing during solder bump formation. The potential for droplet bouncing is modeled based on the energy difference between the maximum spreading and equilibrium sessile stages of a deposited droplet. Validated by experimental results, the model shows that strong droplet-surface wetting can significantly reduce the tendency for a deposited droplet to bounce. The effect of surface droplet can sometimes recoil violently after the initial spreading and rebound off the target surface. Such behavior, known as bouncing, has a strong influence roughness on the bouncing potential is represented by the roughness-induced incomplete wetting during droplet deposition, a phenomenon quantified by a change in the effective contact area under the deposited droplet. An idealized surface model is used to represent the real surface and to describe the relationship between various roughness parameters to changes in the effective contact area. The theoretical analysis, validated by empirical data, shows that surface effective
(cont.) contact area. The theoretical analysis, validated by empirical data, shows that surface roughness promotes bouncing during solder bump formation. The results from this study suggest that droplet bouncing during solder bump formation may be effectively controlled by improving the surface wetting and minimizing the substrate surface roughness. The knowledge gained is also relevant to other droplet-based manufacturing processes such as spray forming, coating, and rapid prototyping.
by Wen-Kai Hsiao.
Ph.D.
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44

Evteev, Alexander V., Elena V. Levchenko, Irina V. Belova, and Graeme E. Murch. "Formation of a surface–sandwich structure in Pd-Ni nanoparticles by interdiffusion." Universitätsbibliothek Leipzig, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-193359.

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45

Howes, Paul Bedford. "The formation of gold-semiconductor interfaces determined by surface X-ray diffraction." Thesis, University of Leicester, 1993. http://hdl.handle.net/2381/35918.

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46

Brensing, Tess. "Reduction of heterocyclic amine formation in beef by surface application of spices." Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/13120.

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Master of Science
Food Science Institute
J. Scott Smith
Heterocyclic amines (HCAs) are cancer causing compounds formed during the cooking of meat. Previous studies show that incorporating antioxidant spices into meat as well as marinating meat with antioxidant spices reduces formation of HCAs. The purpose of this study was to determine if commercially available spices applied to the surface of meat could effectively reduce HCA formation. Two commercially available spice blends and one blend of spices with known quantities of antioxidant spices were sprinkled onto the surface of beef just prior to pan-frying. The quantities of spices used were based on the amounts customarily consumed in typical Western cooking. The results of direct application were then compared to marinating with the same types and amounts of spices. The antioxidant potential of the spices was analyzed using DPPH and total phenolics methods. Results indicated that the spices would be effective antioxidants. Low recovery rates and problems during the extraction process made results inconclusive, but suggest that further research may find that applying spices directly to the surface of meat in consumer acceptable quantities may be as effective as marinating at reducing the formation of HCAs.
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47

Doeuvre, Loïc. "Formation de plasmine à la surface cellulaire : de la vésiculation à l'apoptose." Caen, 2010. http://www.theses.fr/2010CAEN3126.

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La fibrinolyse et la protéolyse sont gouvernées par la conversion du plasminogène en plasmine à la surface de la fibrine ou de la membrane cellulaire par les activateurs de type tissulaire (tPA) ou urokinase (uPA). Les cellules endothéliales et les neurones, les deux principales sources de tPA, sont en étroite interaction dans l’unité neurovasculaire. La formation de plasmine à la surface des cellules vasculaires adhérentes est un élément prépondérant dans le remodelage matriciel et la migration cellulaire. Une protéolyse accrue perturbe les interactions cellule-matrice et peut ainsi conduire à l’apoptose. En revanche, la réponse directe des cellules adhérentes à la formation de plasmine à leur surface n’est pas caractérisée à ce jour. L’objectif de cette étude a été de considérer ce phénomène au niveau de l’unité neurovasculaire. Nous montrons dans ce travail de thèse que la plasmine formée à la surface des cellules adhérentes produit des effets tant au niveau de la matrice que de la cellule. Au niveau de la matrice, elle induit une protéolyse importante pouvant conduire au détachement cellulaire. La réponse cellulaire est quant à elle divergente : les neurones montrent une survie prolongée au sein d’agrégats cellulaires, tandis que les cellules endothéliales montrent un fort niveau d’apoptose. Cependant, nous avons identifié une réponse primaire commune à l’ensemble des cellules adhérentes : un stade précoce d’activation cellulaire caractérisé par le bourgeonnement membranaire et la libération de microvésicules (0,1 à 1 µm de diamètre). Outre leurs antigènes identitaires et la phosphatidylsérine externalisée, ces microvésicules transportent d’autres molécules actives dont le tPA ou l’uPA. Les microvésicules véhiculant l’uPA participent à un nouveau mécanisme antithrombotique : le « cross-talk fibrinolytique ». Par conséquent, la cellule émet des messagers d’activation précédant le détachement cellulaire et pouvant également agir comme effecteurs dans la communication intercellulaire
Fibrinolysis and proteolysis are both controlled by the conversion of plasminogen into plasmin at the surface of fibrin or at the cell membrane by tissue- (tPA) or urokinase-type (uPA) plasminogen activators. Endothelial cells and neurons, the two main sources of tPA, are in close interaction in the neurovascular unit. Plasmin formed on adherent vascular cells is a key actor in cell-matrix interactions and plays an important role in cell detachment-induced apoptosis. However, the direct response of adherent cells to the formation of plasmin at their surface is still not characterized and was the object of these studies at the level of the neurovascular unit. We show that plasmin besides its effects on the extracellular matrix, also induces direct effects on cells. Cell detachment induced by proteolysis leads to a divergent cell response: neurons form aggregates that has a prolonged survival whereas endothelial cells enter the apoptotic pathway. Interestingly, all adherent cells studied in the present report show a common early stage of cell activation: membrane blebbing and the release of microvesicles (0. 1 to 1 µm in size). Beyond their identity antigens and procoagulant phosphatidylserine, microvesicles carry other bioactive molecules such as tPA or uPA. Microvesicles carrying uPA participate in a new anti-thrombotic mechanism, the fibrinolytic cross-talk. Activated cells release therefore messengers that precede cell detachment and may act as effectors in intercellular communication. For these reasons they are considered as biomarkers of cell activation in pathological states
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48

Rusinovn, P. O., J. M. Blednova, and E. Y. Balayev. "Formation of Multi-functional TiNi Surface Layers via High-speed Flame Spraying." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35286.

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This paper examines the formation of multisurface layers of a material with shape memory effect characteristics, using high-speed flame spraying of TiNi. The control parameters of the process were analysed and optimized spraying regimes applied in order to ensure the formation of a structure with grain size 30 - 170 nm and adhesion strength greater than 60 MPa. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35286
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49

Seantier, Bastien. "Formation et caractérisation d'empreintes moléculaires à la surface de bicouches lipidiques supportées." Université Louis Pasteur (Strasbourg) (1971-2008), 2004. http://www.theses.fr/2004STR13101.

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Ce travail explore une nouvelle méthode de création d'empreintes moléculaires sur surfaces basées sur la réorganisation de la surface induite par un template. Des bicouches lipidiques, concidérées comme un liquide bi-dimensionnel, sont utilisées pour induire une séparation locale et leur transition vers une phase gel pour stabiliser la structure imposée par le template. Ainsi, le processus réversible d'impression est basé sur la transition principale des lipides d'une phase fluide vers une phase gel. Des lipides seuls ou des mélanges de lipides, ayant une température de transition de phase (Tm) proche de la température ambiante, sont utilisés. La composition des membranes lipidiques est responsable de la reconnaissance structurale (têtes) et topologique (longueur des chaînes aliphatiques). Suite au peu de connaissances sur la préparation et les propriétés de ces systèmes, une étude de la formation de bicouches lipidiques supportées (SLBs) proche de leur Tm a été initiée. L'influence des paramètres expérimentaux, tels que la composition et le pH du tampon, la concentration des vésicules, la température et la structure chimique des lipides sur le mécanisme et la cinétique de formation des SLBs, a été étudiée par microbalance à cristal de quartz avec mesure de dissipation (QCM-D). Les résultats montrent en détail comment la formation des SLBs depend des paramètres et, ils permettent de spéculer sur un mécanisme de la formation des SLBs. Ensuite, la formation d'empreintes de deux protéines (un inhibiteur de la trypsine et l'annexine V) a été étudiée avec deux mélanges de lipides. Nous avons développé un protocole expérimental pour analyser leur interaction. Les résultats montrent la présence d'empreintes à la surface des SLBs, la reproductibilité et la réversibilité du processus d'impression. Cependant, les expériences préliminaires soulignent le fait que les empreintes ne sont pas encore hautement spécifiques et que le système lipidique doit être optimisé
This work explores the first step towards a new method for creating molecular imprints on surfaces based on template-induced surface reconstruction. Mixed lipid bilayers are used as a two-dimensional liquid for inducing local demixing and their transition to a gel phase for stabilizing the template-imposed structures. Thus the reversible imprinting process is based on the fluid to gel main transition of lipids, especially phospholipids. Single lipids or lipid mixtures having a phase transition temperature near the ambient temperature are used. The composition of lipid membrane is responsible for the structural fit (lipid headgroups) and a topological fit (legth of aliphatic chains). Since very little is known about the preparation and properties of such systems, a study of the formation of supported lipid bilayers (SLBs) close to their phase transition temperature was initiated. The influence of experimental parameters such as composition and pH of the buffer, the vesicle concentration, temperature and the chemical nature of the lipids on the mechanism and the kinetics of the SLB formation have been studied by dissipation enhenced quartz crystal microbalance (QCM-D), atomic force microscopy (AFM) and fluorescence microscopy. The results show in detail how the formation of SPBs depends on experimental parameters and allow to speculate on a more detailed mechanims of SPB formation. Then, the imprint formation of two proteins (trypsin inhibitor and annexin V) have been studied with two lipid mixtures. We have developed an experimental protocol to analyse their interaction. The results show the presence of molecular imprints at the surface of lipid membranes, the reproducibility and the reversibility of molecular imprinting process. However, the preliminary experiments exhibit the fact that the imprints are not yet highly specific and that the lipid system needs to be optimised further
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50

Atkinson, Lee. "Ullmann Dehalogenation of Dibromoferrocene for the formation of surface-confined molecular rotors." Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/208016/3/Lee_Atkinson_Thesis.pdf.

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Abstract:
This thesis is an experimental investigation into the potential of ferrocene for fabricating surface-confined molecular rotors. The investigation was performed in ultra-high vacuum on gold and silver 111 surfaces, utilising Ullmann dehalogenation of dibromoferrocene as a method of forming stable organometallic assemblies. Analysis was performed using X-ray photoelectron spectroscopy, scanning tunnelling microscopy and near edge X-ray absorption fine structure quantitative methods. A density functional theory investigation of the rotational barriers of gas-phase ferrocene and dibromoferrocene, as well as surface adsorbed ferrocene geometry optimisation on silver 111, was also performed. Results indicate potential methods for forming surface-confined molecular rotors from dibromoferrocene.
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