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Bijel : a novel composite material from colloids on liquid-liquid interfacesHerzig, Eva M. January 2008 (has links)
Composite materials generally consist of different components which individually exhibit an entirely different material behaviour than within the composite. Here, two immiscible liquids are stabilised with solid particles forming liquid-liquid emulsions. Solid stabilised emulsions, also known as Pickering emulsions, have been thoroughly studied and find application in many industrial sectors. In these emulsions one liquid is generally suspended within the other in the form of droplets. Inspired by computer simulations, it should be possible to create a bicontinuous network of two immiscible liquids also stabilised with jammed particles. This will result in an attractive new material which could find possible industrial applications, for example as microreactors. This potential bicontinuous, interfacially jammed emulsion gel was dubbed bijel. Drawing together knowledge from different disciplines this thesis presents an experimental route to bijel formation. Accessing a certain type of phase separation called spinodal decomposition can be used to create a convoluted arrangement of bicontinuous interfaces. Liquid-liquid interfaces can be stabilised by exploiting the fact that solid particles can be irreversibly trapped at liquidliquid interfaces. Once trapped, the presence of the particles demands a minimum interfacial area between the two liquids. If the particles are jammed against each other this will result in the stabilisation of the liquid-liquid interfaces. To stabilise convoluted, bicontinuous interfaces in this way one type of particles must be able to concurrently stabilise two types of curvatures. Over the last three years it has been shown by several different research groups that this is possible. This thesis examines different types of temperature and pressure quenches on binary liquid systems to reach spinodal decomposition in the presence of particles. At the same time the ability of the particles to collect on the interfaces created during such phase separations is tested. It is found that temperature quenches through the critical point can lead to reproducible bijel formation resulting in the first experimental presentation of bijels. Using confocal microscopy the bijel formation process is studied in detail and properties of this new material are examined. To obtain insight into the behaviour of slowly ageing soft materials xray photon correlation spectroscopy is separately carried out on droplet emulsions.
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Automated Method Development for Measuring Trace Metals in the Open OceanSchwanger, Cassie 20 September 2013 (has links)
New approaches to the analysis of trace metal concentrations in seawater have the potential to advance the field of oceanography and provide a more comprehensive understanding of the marine biogeochemical cycles of trace metals and the processes regulating these cycles. Traditional oceanographic methods of trace metal analysis were developed several decades ago using benchtop liquid-liquid extraction (Danielson et al., 1978; Kinrade and Van Loon, 1974; Miller and Bruland, 1994; Moffett and Zika, 1987). More modern techniques utilize flow based solid phase extraction to eliminate the high ionic strength matrix to determine dissolved concentrations with great accuracy and precision but do not allow for the determination of metal speciation in solution (Wells and Bruland, 1998). The method developed here measures oceanographically relevant concentrations of copper (Cu) in seawater via chemiluminescence (Marshall et al., 2003 and Coale et al., 1992) and micro-molar levels of silver (Ag) colorimetrically after automated liquid-liquid extraction. The Zone Fluidics (Marshall et al., 2003) analyzer for trace Cu determined SAFe D2 standard seawater (www.geotraces.org) to be 1.77 nM Cu comparable to the expected consensus value. The method was used to determine dissolved Cu depth profiles for major stations along the Line P Time-series transect (48N 125W - 50N 145W) in the Pacific Ocean during February 2011. This method consumes less than 200 µL of sample and reagents and is performed in less than 3 minutes making it suitable for ship or lab based analysis. / Graduate / 0485 / 0425 / cschwang11@gmail.com
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Contact angle measurements on perticulate systems /Stevens, Nathanael I. Unknown Date (has links)
Conventional techniques for contact angle measurements do not perform well for small particles. The equilibrium capillary pressure technique (ECP) consists in measuring the pressure required to prevent liquid penetration into a packed bed of particles and calculating the contact angle from a simple model, namely the equilavent capillary model. The ECP is well suited for the measurement of advancing contact angles. In its most convenient version the capillary pressure is measured for two different liquids (one of which is fully wetting and thus allows the calculation of the effective capillary radius). The use ECP to obtain the receding contact angle on powders has been developed. The major difference bertween a liquid penetrating a porous bed and retreating from it is that liquid pockets are left behind in the receding case. Effectively, this reduces the porosity of the packed bed. The volume fraction of the retained liquid apparently depends on the surface tension of the liquid but is only marginally affected by the wettability and size fraction of the particles. Therefore a simple procedure for the determination of the receding contact angle, based on the use of a calibrating liquid, is outlined and verified. The approach gives realistic values for the receding contact angle. / Thesis (PhDApSc(MineralsandMaterials))--University of South Australia, 2005.
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Interactions between colloidal particles at oil-water interfacesPark, Bum Jun. January 2008 (has links)
Thesis (M.Ch.E.)--University of Delaware, 2007. / Principal faculty advisor: Eric M. Furst, Dept. of Chemical Engineering. Includes bibliographical references.
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Investigations of the molecular structure and bonding of water at the liquid-liquid interface utilizing vibrational sum-frequency spectroscopy /McFearin, Cathryn LeAn, January 2009 (has links)
Typescript. Includes vita and abstract. Includes bibliographical references (leaves 104-120) Also available online in Scholars' Bank; and in ProQuest, free to University of Oregon users.
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Deconvolution of mobile phase contributions to band broadening in reversed-phase liquid chromatographySimmons, Carolyn Rebecca. Dorsey, John G. January 2005 (has links)
Thesis (Ph. D.)--Florida State University, 2005. / Advisor: John G. Dorsey, Florida State University, College of Arts and Sciences, Dept. of Chemistry and Biochemistry. Title and description from dissertation home page (viewed Jan. 25, 2006). Document formatted into pages; contains xxiii, 132 pages. Includes bibliographical references.
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Electrooptical modes of liquid crystal for shutter and display applications /Xu, Peizhi. January 2005 (has links)
Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references (leaves 104-115). Also available in electronic version.
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Processing, characterizations and optical modeling of color filter liquid-crystal-on-silicon microdisplays /Zhang, Baolong. January 2006 (has links)
Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2006. / Includes bibliographical references. Also available in electronic version.
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Mechanically stabilized bistable FLCD on flexible substrates /Au, Ping Tong. January 2006 (has links)
Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2006. / Includes bibliographical references (leaves 106-110). Also available in electronic version.
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Variable liquid crystal pretilt angles by nanostructured surfaces and their applications /Yeung, Fion Sze Yan. January 2007 (has links)
Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2007. / Includes bibliographical references. Also available in electronic version.
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