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 (48N 125W - 50N 145W) 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

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.

Thesis (M.Ch.E.)--University of Delaware, 2007. / Principal faculty advisor: Eric M. Furst, Dept. of Chemical Engineering. Includes bibliographical references.

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.

xvi, 120 p. : ill. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / The interface between water and an organic liquid is present in a variety of biological, environmental, and chemical processes throughout science and nature. Issues such as environmental remediation and ion transport are governed by the properties of these interfaces, thus the importance of understanding them at the molecular level is apparent. The research in this dissertation shows how the structure and bonding of the liquid-liquid interface changes as the interfacial environment is altered. Vibrational sum-frequency spectroscopy (VSFS), a surface specific, non-linear optical technique, is employed for these interfacial studies. The interfacial OH stretching modes are examined using VSFS under different conditions including organic liquids of varying polarity, as well as addition of acid, base, and salts to the aqueous phase. The effects of these different conditions on the water molecules' interactions both with each other and with the non-aqueous liquid are studied in order to better characterize and understand this important system. The effect of polarity of the non-aqueous phase is presented first through investigations of different mixed halocarbon liquid-water interfaces and the neat chloroform-water interface. These studies show that as the overall polarity of the organic phase increases, the water molecules exhibit less overall orientation and undergo some weak bonding interactions with the non-aqueous liquid. Next, the influence of different salts on the water structure at the interface is studied. Examining this system shows that the dissolved ions, specifically the anions, are present within the interface and significantly alter the orientation and bonding of the interfacial water molecules. The charge, size, and polarizability of the anions all play a role in determining how the water orientation is changed within the interface. Finally, the water-like ions H 3 O + and OH - are examined at the liquid-liquid interface by changing the pH of the aqueous phase through addition of HCl or NaOH. At the extremes of the pH scale, the acid and base have ordering or disordering effects, respectively, on the water structure within the interfacial region. / Adviser: Geraldine Richmond

<p> This report covers two topics. First is the development of computer programs to carry out the calculations needed to determine the control policy to bring a process from one set of steady state conditions to another. Examples of the implementation of control policies for a liquid-liquid extraction column are included. Suggestions have been made for means of decreasing the calculation time and for means of increasing the size of problem that may be solved. </p> <p> The second part discusses an initial project of using a Supernova computer as a direct control computer. Characteristics of direct digital control are illustrated using an analog simulation of the extraction unit as the controlled process. </p> / Thesis / Master of Engineering (MEngr)

With many processing advantages, electrophoretic deposition (EPD) has been chosen as the fabrication technique for inorganic-organic nanocomposites. However, before the EPD process, avoiding the particles agglomeration is considered a necessary perquisite for the success of fabrication. In this research, two different liquid-liquid extraction methods, one is one-step and the other is two-step, were developed to solve the agglomeration problem of inorganic particles. The adsorption mechanisms of the extractors and extraction mechanisms were investigated during this work. The strong adsorptions provided by –OH groups of the extractors and further Schiff base reaction allowed for the process of extraction. In the fabrication, polyelectrolytes acted as the film forming and charging agents. Relatively stable suspensions with extracted inorganic particles were prepared for the EPD of inorganic-organic nanocomposites. The thickness of deposited films is proportional to the concentration of the suspension and deposition time. With the addition of flame retardant inorganic particles, the prepared nanocomposite films showed an enhanced flame retardant performance. / Thesis / Master of Applied Science (MASc)

Master of Science

Two new apparati have been developed to measure solid-liquid and liquid-liquid equilibria via a synthetic visual method by determination of thermal signatures. One apparatus adopts a technique of using Peltier modules for cooling, and the other is a well-known design that uses a cryogenic fluid in a thermostatted glass cell for cooling of the sample. The Peltier design is for small sample volumes, with a 10 cm3 aluminium equilibrium cell and has a minimum operating temperature of 253.15 K. The glass design is developed to complement the Peltier and has a larger volume of 140 cm3 and a minimum operating temperature of 223.15 K. Both apparati have been semi-automated in order to increase the accuracy and improve the efficiency of data measurements. Therefore the experimenter no longer has to wait for many hours for the determination of equilibrium. This was done by incorporating software, which was specially designed for the apparati using Labview8TM, for controlling the cooling and heating rates. The uncertainty of the temperature measurements was found to be ±0.03 K for the Peltier apparatus and ±0.02 K for the Glass apparatus. Liquid-liquid equilibria data has also been measured on the Peltier apparatus, to demonstrate its versatility. This was done using a digital camera, controlled through the Labview software to identify cloud points. The results have been found to be comparable with literature values. For solid-liquid equilibria new systems of n-alkyl carboxylic acid binary mixtures have also been measured: heptanoic acid + butyric acid and heptanoic acid + hexanoic acid. These systems were measured using both apparati and both systems exhibited eutectic behaviour. All eutectic temperatures were measured on the Glass apparatus. Experimental data for these systems was modelled using the local composition models: Wilson, NRTL and UNIQUAC models. The NRTL model was found to give the best results for both systems with root mean square deviations (RMSD) of 2.16 K and 1.27 K and absolute average deviations (AAD) of 0.61 K and 0.49 K, between temperature measurements of this work and those calculated from the models, for the heptanoic acid + butyric acid and heptanoic acid + hexanoic acid systems, respectively. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2010.

This thesis involves a study of the thermodynamics of liquid mixtures containing N-methyl-2pyrrolidone (NMP) and hydrocarbons or ethers. NMP is a polar liquid which is used in liquid extraction procedures for the separation of polar and nonpolar hydrocarbons. It was considered important enough to devote an entire thesis to the properties of NMP related to its interactions with simple hydrocarbons and ethers. The thesis consists of four parts: Part one is devoted to liquid-liquid equilibria. Experimental results at 298.2 K, are presented for the mixtures: NMP + an aromatic hydrocarbon + an n-alkane. Firstly, the effect increasing the chain length of the alkane has on the liquid-liquid equilibria was investigated, by studying mixtures of the type: an n-alkane + toluene + NMP; where the n-alkane refers to n-hexane or n-nonane or n-tetradecane or n-hexadecane. Secondly, the effect of substitution on the benzene ring on the equilibria was studied by measuring the liquid-liquid equilibria for the mixtures: n-hexadecane + an aromatic hydrocarbon + NMP; where the aromatic hydrocarbon refers to toluene or o-xylene or m-xylene or p-xylene or mesitylene or ethyl benzene. The chain length of the n-alkane had a significant effect on the liquid-liquid equilibria. Methyl substitution on the benzene ring had a small effect on the liquid-liquid equilibria. Part two is devoted to activity coefficients at infinite dilution. Experimental results at 298,15 K, determined using gas-liquid chromatography, are presented for the mixtures: NMP (solvent) + n-pentane or n-hexane or n-heptane or n-octane or cyclopentane or cyclohexane or cycloheptane or I-hexene or 1-heptene or l-octene or diethyl ether or diisopropyl ether. The magnitudes of the infinite dilution activity coefficients had the following order: n-alkanes > cycloalkanes > l-alkenes > ethers. Part three is devoted to excess molar enthalpies. Experimental results at 298.15 K are presented for the mixtures: NMP + an aromatic hydrocarbon. Here, an aromatic hydrocarbon refers to one of benzene or toluene or o-xylene or m-xylene or p-xylene or mesitylene or ethyl benzene. Isothermal flow microcalorimetry was used to determine the excess molar enthalpies. Increased methyl substitution on the' benzene ring manifests itself as a reduction in the association between NMP and the aromatic hydrocarbon. Part four is devoted to excess molar volumes. Experimental results at 298.15 K are presented for the mixtures: NMP + an aromatic hydrocarbon. Here, an aromatic hydrocarbon refers to one of benzene or toluene or o-xylene or m-xylene or p-xylene or mesitylene or ethyl benzene. Densitometry was used to determine the excess molar volumes. The excess molar volumes were negative for all the mixtures. / Thesis (M.Sc.)-University of Natal, 1997.