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Theoretical study of heat distribution and surface temperatures generated in oscillating contact /Foo, Ser Jee, January 1990 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaves 90-93). Also available via the Internet.
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Surface properties of poly(ethylene terephthalate) /Matthews, Thomas R. January 2007 (has links)
Thesis (M.S.Ch.E.)--University of Toledo, 2007. / Typescript. "Submitted as partial fulfillment of the requirements for The Masters of Science Degree in Chemical Engineering." Bibliography: leaves 76-77.
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Infrared measurements of surface temperatures during oscillating/fretting contact with ceramics /Weick, Brian L., January 1990 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaves 230-235). Also available via the Internet.
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Orientation, microstructure and pile-up effects on nanoindentation measurements of FCC and BCC metalsSrivastava, Ashish Kumar. Mirshams, Reza, January 2008 (has links)
Thesis (M.S.)--University of North Texas, May, 2008. / Title from title page display. Includes bibliographical references.
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Compositional analysis of glass surfaces and their reaction in aqueous environmentsPantano, Carlo G. January 1976 (has links)
Thesis--University of Florida. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 175-181).
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Global finish curvature matched machining /Wang, Jianguo, January 2005 (has links) (PDF)
Thesis (M.S.)--Brigham Young University. Dept. of Mechanical Engineering, 2005. / Includes bibliographical references (p. 73-75).
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Use of the equilibrium contact angle as an index of contact surface cleanlinessYang, Jianguo 18 December 1990 (has links)
Advancing contact angles formed by water and aqueous ethanol solutions were
measured on both bare surfaces and film-covered surfaces of acrylic, glass, hydrophilic
and hydrophobic silicon, polycarbonate, polyester, and stainless steel. Each bare surface
was initially characterized with respect to its hydrophilic - hydrophobic balance. Both
protein films and milk films were prepared on each surface; the adsorbed mass comprising
each film was measured with ellipsometry. Contact angle methods proved useful in
detecting the presence of a protein film on sufficiently hydrophilic or sufficiently
hydrophobic surfaces. Contact angle methods were also found to be useful for detecting the
presence of a milk film on sufficiently hydrophilic solid surfaces. The results also indicated
that the type of diagnostic liquid chosen for the analysis becomes an important factor for
films of increasing complexity. In any event, contact angle analysis is inappropriate to
quantify the actual mass of soil remaining on a solid surface. / Graduation date: 1991
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Synthesis and application of alkyl dihydrochlorosilanes: A new approach to the surface modification of porous silica.Golding, Randy Dale. January 1988 (has links)
Three alkyldihydrochlorosilanes were synthesized; ethyldihydrochlorosilane, octyldihydrochlorosilane and octadecyldihydrosilane. Ethyldihydrochlorosilane was produced by the reaction of ethylsilane with mercuric chloride and the other two chlorosilanes were produced by the reaction of the alkyl Grignard reagent with dichlorosilane. Each alkyldihydrochlorosilane was reacted with porous silica in an attempt to discover the extent of reaction or the highest surface concentration of bonded groups attainable. The reaction between these alkydihydrochlorosilanes and porous silica was compared to the reaction between silica and the analogous alkyldimethylchlorosilane. The rate of reaction of both type of chlorosilane was found to be essentially the same. The maximum surface concentration of bonded surface groups attainable by alkyldihydrochlorosilanes was found to be approximately 1.3 #moles/m² greater than that attainable by alkyldimethylchlorosilanes. This increased surface coverage seemed to depend very little on the chain length of the alkyl group and was attributed to the decrease in steric hindrance of the bonding silicon atom of the silane. Surface bound silyl hydrides could be oxidized selectively and sequentially to form silane silanols. Surface silanes also appeared to reduce chloroplatinic acid, but were not observed to add efficiently to olefins. The chromatographic properties of silica modified with alkyldihydrochlorosilanes were compared to those of equivalent silicas modified with alkyldimethylchlorosilanes and alkyltrichlorosilanes before and after the surface silanes were oxidized. Both normal and reversed-phase liquid chromatographic studies were conducted. In general, it was found that alkyldihydrochlorosilanes yielded the most polar modified silicas. This greater surface polarity was attributed to an increase in the activity of water in the near surface region of the bonded phase.
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Rapid and low-cost mass fabrication of true three-dimensional hierarchical structures with dynamic soft molding and its application in affordable and scalable production of robust and durable whole-teflon superhydrophobic coatingLi, Wanbo 01 February 2019 (has links)
Superhydrophobic (SH) surfaces equipped on the skins of natural living beings give them trumps of self-cleaning, anti-bacterial, water harvest, and directional liquid transport, etc., to survive in harsh environments. Bioinspired Superhydrophobic (SH) surfaces have developed many emerging functions, such as self-cleaning, anti-bacterial, water harvest, anti-icing, anti-corrosion, oil-water separation, and many other fascinating functions. However, the implementations of SH coating in real world are still in its infancy, due to (i) the poor performance in the harsh real-world environment and industrial process application, where a multi-level robustness including the mechanical, chemical, and thermal robustness, as well as the strong adherent strength to substrates, is strictly required; (ii) the lack of a technology for facile and mass production. In the light of that any non-perfluorinated component in the formula of an SH coating inevitably generates vulnerable points to the external invasions and the functional applications of SH coatings require control surface topography, we here propose an SH coating entirely made of perfluorinated materials (referred to as Teflon). To achieve this goal, we developed a complete strategy involving material, fabrication, and applications. Firstly, we developed a feasible dynamic soft molding method for the fabrication of three-dimensional (3D) structures. This method paves a road not only to the fabrication of whole-Teflon SH coatings but also to the practical adoption of many other important technologies based on 3D structures. Secondly, we generated whole-Teflon and multi-resist SH coatings by using this method and tightly attached them to different substrates with superior adhering strength surpassing the conventional work. Thirdly, we performed a proof-of-concept demonstration of a roll-to-roll (R2R) hot molding process, which has the potential of translating the lab-scale and plate-to-plate fabrication to industrial mass production. Finally, some fundamental mechanisms and problems of the multifunctional applications in self-cleaning, anti-bacterial fouling, and anti-icing are studied. The outcomes are expected to provide insight understandings on the multifunctional SH coating and move SH coatings toward real-world application.
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Plasma-induced modification of films containing polytetrafluoroethylene (PTFE)Jones, Hyrum E. 08 June 2005 (has links)
Polymer samples of polytetrafluoroethylene (PTFE) and a PTFE-glass weave (RF-
35P) are exposed to low pressure, non-equilibrium glow discharge plasmas for
enhanced wettability as measured by static contact angles. Plasma treatments are
performed in two parallel plate RF plasma systems, a downstream microwave plasma
and a barrel etcher using feed gases composed of H₂, N₂, Ar, He, and 0₂. Surface
analysis of the topography and chemical composition of treated samples is performed
by atomic force microscopy (AFM), attenuated total reflection infrared (ATR-IR)
spectroscopy, x-ray photoelectron spectroscopy (XPS) and time-of-flight secondary
ion mass spectroscopy (ToF SIMS). Optical emission spectroscopy is used to correlate
wettability to reactive species in the plasma, and plasma parameters to species
emission.
In the parallel plate plasma systems, the contact angle can change from
approximately 95° to 5° with treatment while treatments in the downstream and barrel
etcher systems do not result in a contact angle change. The difference in plasma
performance is attributed to ion bombardment. Plasmas composed of 20 to 80% H₂O in
(H₂ + N₂) give the best wettability improvement. Plasma exposure significantly
reduces the surface fluorine content followed by incorporation of nitrogen, oxygen and
hydrogen, apparently as amino, hydroxyl and carbonyl functional groups with
evidence of an amide. The incorporation of oxygen likely originates through peroxy
radicals subsequent to plasma exposure. It is proposed that using a higher applied
power creates a more reactive surface. A larger percentage of H₂ in the plasma tends
to passivate the surface, leading to a smaller wettability improvement which is
correlated to the atomic hydrogen concentration in the plasma. The addition of He or
Ar into the H₂/N₂ plasma tends to dilute or weaken the plasma effect on wettability.
To a much greater extent, the addition of oxygen also decreases the wettability. This
latter effect is attributed to etching reactions which result in a more hydrophobic
surface. An etch rate of approximately 0.2 μ/min is observed, and this is the first
report of PTFE etching with 0₂/H₂/N₂. The distance between the parallel plate
electrodes (gap) is a significant factor for the wettability of treated polymers, while
power, pressure and flow rate are not. The optimal storage conditions to retain the
wettability of H₂/N₂ plasma-treated RF-35P are low pressure and low temperature.
The following model of PTFE surface modification is proposed. Ion bombardment
creates reactive sites that initiate surface reactions. Reactive species from the H₂/N₂
plasma modify the surface through incorporation of amino, hydroxyl and carbonyl
surface groups. These new groups increase the polymer wettability. Atomic hydrogen
in the mixture is required to improve the wettability, but too high of a concentration
will passivate the surface and lessen the wettability improvement. If oxygen is present,
the modified surface is etched away leaving a refreshed, more hydrophobic surface. / Graduation date:2006
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