Includes bibliographical references (p. 78-89).

The first study focused on the magnitude and rate of sorption of hydrophobic organic compounds by two, well-characterized soils. The composition of organic matter had a small effect on the magnitude of the organic carbon normalized equilibrium distribution coefficients. The sorbates sorbed more strongly to the humic-coated soil, most likely due to the organic matter's less polar nature as compared to the fulvic material. The molecular solute descriptor, ¹Xᵛ, performed slightly better than the empirical solute descriptor, K(ov), in evaluating equilibrium sorption coefficients. Thus, sorbate structure may have a secondary influence on the overall magnitude of equilibrium sorption. Sorbate structure exhibited a greater influence on sorption kinetics than on sorption equilibrium. Distinct differences in the magnitudes of mass transfer coefficients for the humic and fulvic soils were observed when relating them to the molecular solute descriptor, ¹Xᵛ. The differences in mass transfer coefficients were attributed to both sorbate structure and the quantity and morphology of soil organic matter. The intrasorbent diffusion coefficients were believed to be the same for both the humic and fulvic material. The second study focused on using a biodegradable solute to measure processes that affect in-situ biodegradation during well-controlled field and laboratory experiments. Specifically, this study investigated how residence time and scale influence the extent and rate of in-situ biodegradation of an organic solute undergoing transport. The transport of the biodegradable solute was compared to that of bromide and/or pentafluorobenzoic acid, which are conservative, non-degradable tracers. Laboratory experiments were conducted to simulate both the flow velocity and residence time conditions existent in the field. Mass recovery the biodegradable solute decreased as the residence time increased, ranging from 14 to 95 percent for the field sites. Mass recoveries in the laboratory experiments were approximately 30% to 40 % less than in the field experiments. The first-order biodegradation rate constants did not vary with residence time for either field site. In addition, the average rate constant value for both field sites was very similar (0.21 d⁻¹).

Thesis (PhD)--University of South Australia, 2004.

Thesis (PhD) -- University of South Australia, 1994

Interactions between proteins and contact surfaces can have important implications in the food industry. Such interactions contribute to the course of fouling of membrane surfaces and they appear to mediate bacterial and spore adhesion to some degree as well. In addition to protein and solution properties, interfacial behavior is strongly influenced by contact surface properties. Among these, hydrophobicity and the potential to take part in acid-base interaction have received considerable attention, but in a quantitative sense we know very little about their respective influences on protein adsorption. It was the purpose of this research to quantify the equilibrium adsorptive behavior of the milk protein β-lactoglobulin as it is influenced by the presence of different contact surface functional groups. Monocrystalline and polished silicon surfaces were modified to be hydrophilic by oxidation and hydrophobic by silanization with dichlorodiethylsilane (DDES), dichlorodimethylsilane (DDMS), and dichlorodiphenylsilane (DDPS), each used at concentrations of 0.82, 3.3, and 82 mM. Surface hydrophobicities were evaluated with contact angle methods. Adsorption isotherms were constructed after allowing each modified silicon surface to independently contact β-lactoglobulin (0.01 M phosphate buffer, pH 7.0) at concentrations ranging between 200 and 2000 mg/L for eight h at room temperature. Surfaces were then rinsed and dried. Optical properties of the bare- and film-covered surfaces, necessary for calculation of adsorbed mass, were obtained by ellipsometry. Plots of adsorbed mass as a function of protein concentration exhibited attainment of plateau values beyond a protein concentration of about 200 mg/L. At high silane concentration, the plateau values associated with surfaces exhibiting ethyl groups were observed to be greatest followed by those exhibiting phenyl, methyl, then hydrophilic (OH) groups. At the low DDMS and DDES concentrations (0.82 and 3.3 mM), adsorbed mass did not increase beyond that value recorded for the hydrophilic surface. This is likely due to some critical spacing of methyl and ethyl groups being required to produce a favorable hydrophobic effect on adsorption. For surfaces treated with dichlorodiphenylsilane, adsorbed mass increased with silane concentration. Apparently, a favorable acid-base interaction effected by the hydrophilic surface is inhibited by the presence of small amounts of methyl and ethyl groups, but somewhat less inhibited by the presence of phenyl groups because the latter have the ability to undergo acid-base interaction. / Graduation date: 1993

Nisin is an antibacterial peptide, which when adsorbed on a surface can inhibit bacterial adhesion and viability. The ability of noncovalently immobilized nisin to withstand exchange by the milk proteins bovine serum albumin, ��-lactoglobulin, ��-lactalbumin, and ��-casein on surfaces that had been silanized with dichlorodiethylsilane to exhibit high and low hydrophobicities was examined using in situ ellipsometry. Kinetic behavior was recorded for nisin adsorption for 1h and 8h, followed in each case by rinsing in protein-free buffer solution, and sequential contact with a single milk protein for 4h. Concerning nisin adsorption to each surface, a higher adsorbed mass was consistently recorded on the hydrophilic relative to the hydrophobic surface, independent of adsorption time. While desorption was greater from the hydrophilic surface in the 1h test, the amount desorbed was quite similar on each surface in the 8h tests. The sequential data were consistent with the assumptions that nisin organization at the interface involved adsorption in at least two different states, possibly existing in more than one layer, and that in the absence of exchange, upon addition of the second protein adsorbed mass would increase by an amount equivalent to its experimentally observed monolayer coverage. The Mass of nisin exchanged was generally higher on the hydrophobic compared to the hydrophilic surface presumably because of the presence of a more diffuse outer layer in the former case. ��-casein was the most effective eluting agent among the proteins studied, while ��-lactalbumin was the least effective, apparently adsorbing onto the nisin layers with little exchange. Both bovine serum albumin and ��-lactoglobulin were moderately effective in exchanging with adsorbed nisin, with the amount of nisin removed by bovine serum albumin being more substantial, possibly due to its greater flexibility. / Graduation date: 1995

Thesis (Ph.D.)--University of Delaware, 2007. / Principal faculty advisor: Joel P. Schneider, Dept. of Chemistry & Biochemistry. Includes bibliographical references.

Thesis (Ph. D.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 136-139). Also available on the World Wide Web.

Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2010. / Committee Chair: Breedveld, Victor; Committee Chair: Hess, Dennis; Committee Member: Aidun, Cyrus; Committee Member: Deng, Yulin; Committee Member: Singh, Preet. Part of the SMARTech Electronic Thesis and Dissertation Collection.

In the past decade, the condensation on superhydrophobic surfaces has been investigated abundantly to achieve dropwise condensation. There is not a specific approach in choosing the size of the roughness of the superhydrophobic surfaces and it was mostly selected arbitrarily to investigate the behavior of condensates on these surfaces. In this research, we are optimizing the size of the roughness of the superhydrophobic surface in order to achieve dropwise condensation. By minimizing the resistances toward the transition of the tails of droplets from the cavities of the roughness to the top of the roughness, the size of the roughness is optimized. It is shown that by decreasing the size of the roughness of the superhydrophobic surface, the resistances toward the transition of the tails of droplets from Wenzel state to Cassie state decrease and consequently dropwise condensation becomes more likely.