ORCID Profile
0000-0002-9094-7278
Current Organisation
University of South Australia
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Publisher: Springer Science and Business Media LLC
Date: 14-08-2009
Publisher: Elsevier BV
Date: 02-2010
Publisher: Elsevier BV
Date: 09-2006
Publisher: Elsevier BV
Date: 12-2004
Publisher: Elsevier BV
Date: 12-1992
Publisher: Elsevier BV
Date: 02-2005
Publisher: Elsevier BV
Date: 1998
Abstract: The collection efficiency of single bubbles rising through a very dilute pulp of hydrophobized quartz particles has been determined. Measurements have been performed under conditions in which the bubble surface is mobile, as a function of electrolyte concentration, particle diameter (7 to 70 &mgr m), bubble diameter (0.77 x 10(-3) to 1.52 x 10(-3) m), and particle advancing water contact angle. Situations in which the product of attachment and stability efficiency is at its maximum value have been identified, permitting a stringent, critical test of collision theory to be performed. A collision theory has been developed which accounts for the influence of positive and negative inertial forces in the case of bubbles with mobile surfaces. The approach considers only long-range hydrodynamic interactions under conditions where short-range interactions are strongly suppressed (i.e., high particle contact angle and high electrolyte concentrations) and attachment occurs at first collision. In this instance, good agreement between theory and experiment is achieved for particle diameters between 7 and 60 &mgr m and Stokes numbers up to 0.27. The analytical equation developed is termed the generalized Sutherland equation (GSE). Copyright 1998 Academic Press. Copyright 1998Academic Press
Publisher: Elsevier BV
Date: 11-2012
DOI: 10.1016/J.CIS.2012.06.008
Abstract: A model of collision and collection of Brownian submicron particles based on the creation of a convective-diffusion layer near a bubble surface and overcoming the energy barrier created by particle/bubble interaction is developed. Simple analytical expressions describing the rate of collision and collection efficiency are obtained. The collision and collection minimums and the limits of theory applicability are analysed.
Publisher: Elsevier BV
Date: 06-2005
DOI: 10.1016/J.JCIS.2005.01.028
Abstract: The foam behavior of three polypropylene glycols covering the molecular weight range between 192 and 725 g/mol has been examined. Static and dynamic surface tension data, as well as bubble size distribution and retention time in the foam, were incorporated into a simple model of foam stability. The latter clearly indicates that surface tension differences between the plateau border and lamellar region adjacent to the bubble surface are the dominant factor in controlling foamability, causing liquid flow in the direction opposite to liquid drainage, a process termed the Marangoni effect.
Publisher: Elsevier BV
Date: 09-2003
DOI: 10.1016/S0021-9797(03)00345-X
Abstract: An analytical model that enables the calculation of the flotation rate constant of particles as a function of particle size with, as input parameters, measurable particle, bubble, and hydrodynamic quantities has been derived. This model includes the frequency of collisions between particles and bubbles as well as their efficiencies of collision, attachment, and stability. The generalized Sutherland equation collision model and the modified Dobby-Finch attachment model developed previously for potential flow conditions were used to calculate the efficiencies of particle-bubble collision and attachment, respectively. The bubble-particle stability efficiency model includes the various forces acting between the bubble and the attached particle, and we demonstrate that it depends mainly on the relative magnitude of particle contact angle and turbulent dissipation energy. The flotation rate constants calculated with these models produced the characteristic shape of the flotation rate constant versus particle size curve, with a maximum appearing at intermediate particle size. The low flotation rate constants of fine and coarse particles result from their low efficiency of collision and low efficiencies of attachment and stability with gas bubbles, respectively. The flotation rate constants calculated with these models were compared with the experimental flotation rate constants of methylated quartz particles with diameters between 8 and 80 micro m interacting with gas bubbles under turbulent conditions in a Rushton flotation cell. Agreement between theory and experiment is satisfactory.
Publisher: Elsevier BV
Date: 09-1999
Publisher: American Chemical Society (ACS)
Date: 04-1988
DOI: 10.1021/J100319A040
Publisher: Royal Society of Chemistry (RSC)
Date: 1999
DOI: 10.1039/A900974D
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/C0CP01367F
Abstract: The contact between fine hydrophilic α-Al(2)O(3) particles and nitrogen bubbles was studied as a function of solution composition in single bubble capture experiments, where the bubble collection efficiency was measured. The surface charges of both bubble and particle were controlled by varying the electrolyte concentration and pH of the solution. In all experiments the bubbles were negatively charged while the α-Al(2)O(3) particles were either negatively (above pH of the isoelectric point, pH(IEP)) or positively (below pH(IEP)) charged. The collection efficiency was found to be strongly influenced by the surface charge of the particles. The maximum collection efficiency occurred when the bubble and particle were oppositely charged (at low pH values) and at low salt concentration, i.e. when a long range attractive electrostatic interaction is present. In the case where both bubble and particle were of the same charge, the collection efficiency was near to zero within experimental error and was not influenced by either salt concentration or pH. This is the first experimental proof of the concept of 'contactless flotation', first proposed by Derjaguin and Dukhin in 1960, with far reaching implications from minerals processing to biology.
Publisher: Elsevier BV
Date: 02-2010
DOI: 10.1016/J.JCIS.2009.10.068
Abstract: We have studied the stability and structure of emulsions formed in the presence of colloidal mixtures of partially hydrophobic titania particles and hydrophilic silica particles. On their own, the titania particles attached strongly to the oil-water interface and stabilised emulsions, while the silica particles did not attach to the interface. Adding silica particles to the titania dispersions enhanced coalescence processes during emulsion formation, except under mixing conditions that favoured particle heteroaggregation. The destabilisation of the emulsions was linked to the presence of silica particles in the particle layers at the interface.
Publisher: Elsevier BV
Date: 05-1994
Publisher: Elsevier BV
Date: 1992
Publisher: Elsevier BV
Date: 05-1994
Publisher: American Chemical Society (ACS)
Date: 14-10-2010
DOI: 10.1021/LA103351T
Abstract: The wettability of a titania surface, partially covered with octadecyltrihydrosilane, has been investigated as a function of solution pH. The results show that surface charge affects both static wettability and wetting kinetics. The static contact angle decreases above and below the point of zero charge of the titania surface in a Lippman-like manner as the pH is altered. The dependence of dynamic contact angle on velocity is also affected by pH. The molecular-kinetic theory (MKT) is used to interpret the dynamic contact angle data. The frequency of molecular displacement κ(0) strongly varies with surface charge, whereas the mean molecular displacement length λ is essentially unaffected. There is an exponential dependence of contact-line friction upon work of adhesion, which is varied simply by altering the pH.
Publisher: American Chemical Society (ACS)
Date: 13-05-1999
DOI: 10.1021/LA981525W
Publisher: Wiley
Date: 08-1984
DOI: 10.1111/J.1432-1033.1984.TB08330.X
Abstract: The circular dichroism and absorption spectra of the stacked and unstacked forms of ApA and dApdA were derived. The unstacked spectra are not identical with the corresponding free nucleoside spectrum. The stacked spectra can be satisfactorily described in terms of the vibronic degenerate exciton theory which suggests that the non-degenerate interactions have a less important influence on the observed circular dichroic spectra than hitherto assumed. From the experimental spectra the magnitudes of the exciton coupling were found to correspond to very fast transfer rates of energy between the adenine moieties. The absorption spectra of the stacked species are consistent with average angles of near 60 degrees and 20 degrees in ApA and dApdA, respectively, between the degenerate transition moments of the adenine moieties.
Publisher: Elsevier BV
Date: 06-1985
Publisher: Elsevier BV
Date: 07-2013
Publisher: MDPI AG
Date: 14-10-2016
DOI: 10.3390/MIN6040105
Publisher: Elsevier BV
Date: 2019
Publisher: Elsevier BV
Date: 2009
DOI: 10.1016/J.JCIS.2008.09.056
Abstract: We investigated the structure and stability of dodecane-in-water emulsions stabilised by partially hydrophobised silica particles after dilution of the emulsions in solutions of sodium dodecyl sulfate and sodium chloride. The emulsions were stable to coalescence on dilution in salt solutions, but did cream over time. The rate and extent of creaming gradually decreased as the salt concentration in the diluted emulsion increased. Dilution in low concentrations of the anionic surfactant did not affect the emulsion stability to coalescence or alter the creaming behaviour of the emulsion. At surfactant concentrations above the critical micelle concentration, however, the rate and extent of creaming and flocculation of the drops were enhanced.
Publisher: Elsevier BV
Date: 08-2004
Publisher: Elsevier BV
Date: 02-2001
Publisher: Elsevier BV
Date: 2015
Publisher: Elsevier BV
Date: 12-2005
Publisher: American Chemical Society (ACS)
Date: 03-1981
DOI: 10.1021/J150605A032
Publisher: CSIRO Publishing
Date: 1988
DOI: 10.1071/CH9881331
Abstract: From the concentration dependence of the spectrum of 9-aminoacridine hydrochloride in neutral aqueous solution we determined the spectrum of the dimeric dye species. Two further 'dimeric' spectra' of the 9- aminoacridine chromophore have been obtained as the low- and high-temperature forms of N,N′- di (acridin-9-yl)hexane-1,6-diamine in aqueous solution. We interpreted the dimer spectra in the region between about 245 and 275 nm in terms of vibronic exciton theory and discussed the implications of the results to the structure of the dimers . Application of vibronic exciton theory to the visible region of the dimer spectra has resulted in at most qualitatively acceptable fits only, due to the breakdown in this region of the spectra of the single dominant vibrational mode approximation.
Publisher: Elsevier BV
Date: 06-2001
Publisher: Elsevier BV
Date: 05-1991
Publisher: American Chemical Society (ACS)
Date: 04-1981
DOI: 10.1021/JA00398A006
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 04-1987
DOI: 10.1097/00004424-198704000-00008
Abstract: Paramagnetic complexes of manganese(II), iron(III), and gadolinium(III) with many ligands appear to undergo ligand substitution in vivo, producing biodistribution data similar to the hydrated metal ions. To identify ligands likely to be valuable in the preparation of paramagnetic contrast agents, a series of aminopolycarboxylate complexes with stability constants increasing in the order iminodiacetic acid (IDA) less than nitrilotriacetic acid (NTA) less than EDTA less than CDTA less than or equal to DTPA was prepared with 54Mn(II), 59Fe(III), and 153Gd(III) at both tracer and carrier levels. Biodistribution studies in mice suggested that complexes remained unchanged in vivo if their stability constants (K1) were approximately greater than 10(16) for Mn(II) and Gd(III) and greater than 10(22) for Fe(III) complexes at tracer levels. Metal complexes with added carrier appeared to be effectively more stable in vivo, possibly due to dissociation and saturation of metal-binding sites. To avoid the accumulation of metal ions in tissues, new paramagnetic contrast agents containing these metal ions will require stability constants equal to or greater than those identified here.
Publisher: Springer Science and Business Media LLC
Date: 05-09-2011
Publisher: Royal Society of Chemistry (RSC)
Date: 1993
DOI: 10.1039/FT9938900817
Publisher: Elsevier BV
Date: 02-2005
Publisher: Informa UK Limited
Date: 03-2009
DOI: 10.1080/08982100802673940
Abstract: The encapsulation and release kinetics of guanosine from liposomes and polyethylene glycol (PEG)-modified liposomes are reported. Specifically, the influence of PEG chain length, PEGylation level, lipid type, drug-loading level, temperature, and solution conditions (i.e., salt and pH effects) on the rate and mechanism for release have been determined. Increasing PEGylation significantly reduced the guanosine release kinetics this is more significant for greater molecular weight PEG and is correlated with the PEG layer thickness. Further, the mechanism for guanosine release changed from diffusion to interfacial control as the PEG level increased. The interfacial structure introduced by PEG also increased the activation energy required for guanosine transport across the lipid bilayer from 14 to 22 kJ mol(-1). Findings from this study provide further insight into optimizing the formulation of Stealth liposomes.
Publisher: Elsevier BV
Date: 09-2010
DOI: 10.1016/J.JCIS.2010.05.089
Abstract: The remarkable stability of nanoparticles attached to oil-water interfaces in macroemulsions hinders controlled detachment of these particles from emulsions. In this work it is shown that adding surfactant molecules which preferentially adsorb at the oil-water interface displaces nanoparticles from the interface. Surfactant adsorption at the oil-water interface is energetically favoured and readily occurs on mixing nanoparticle-stabilised oil-in-water emulsions with surfactant solutions. Depending on the surfactant concentration, there is a significant reduction in the interfacial tension. Hence there is substantial fragmentation of the oil droplets and foaming of the emulsion during mixing. Surfactant concentrations above the critical micelle concentration are required to achieve complete interfacial displacement and hence recovery of the nanoparticles from the emulsions. The effects of surfactant addition have important implications for tailoring the interfacial composition of emulsions.
Publisher: American Chemical Society (ACS)
Date: 17-05-2011
DOI: 10.1021/JP200387W
Publisher: Elsevier BV
Date: 11-1985
DOI: 10.1016/0301-4622(85)80061-2
Abstract: Absorption, circular dichroism and steady-state fluorescence spectra were determined of 9-aminoacridine solutions in the presence of DNA at an ionic strength of 0.001 mol dm-3. Up to a dye/DNA phosphorus ratio of about 0.2 the results are fully consistent with the requirements and predictions of a binding model already shown to apply to the binding of other aminoacridines to DNA. The apparently anomalous spectroscopic behaviour of the 9-aminoacridine/DNA system compared with proflavine/DNA, for ex le, can be satisfactorily explained from a consideration of the magnitudes of exciton interactions between dyes bound to DNA.
Publisher: Elsevier BV
Date: 04-1999
Publisher: Elsevier BV
Date: 06-2018
Publisher: Elsevier BV
Date: 07-2002
Publisher: Elsevier BV
Date: 11-1995
Publisher: Elsevier BV
Date: 04-2013
Publisher: Elsevier BV
Date: 09-2006
Publisher: Elsevier BV
Date: 03-2000
DOI: 10.1016/S0001-8686(99)00030-5
Abstract: A critical review of the various models existing in the literature for the calculation of the collision efficiency between particles and single, rising gas bubbles is presented. Although all of these collision models predict that the collision efficiency increases with particle size, their dependence on the latter is different because of the various assumptions and hydrodynamic conditions used in each model. Collision efficiencies of quartz particles with single bubbles have been obtained from experimental flotation experiments under conditions where the attachment and stability efficiencies were at, or near, unity. These collision efficiencies were then used to test various collision models. Good agreement between the experimental and calculated collision efficiencies was only obtained with the Generalised Sutherland Equation. The differences in collision efficiencies obtained between the various models were mainly explained in terms of, firstly, the degree of mobility of the bubble surface and, secondly, a consideration of the inertial forces acting on the particles.
Publisher: Royal Society of Chemistry (RSC)
Date: 1995
DOI: 10.1039/FT9959101997
Publisher: Elsevier BV
Date: 2005
Publisher: Elsevier BV
Date: 10-2005
Publisher: Elsevier BV
Date: 11-2012
Publisher: Elsevier BV
Date: 06-2005
DOI: 10.1016/J.JCIS.2005.01.056
Abstract: The colloid stability of synthetic titania particles was studied as a function of KCl concentration at pH values of 6.3, 6.7, and 8.4, using static light scattering to obtain stability ratios. Standard DLVO theory was then used to calculate the stability ratios as a function of salt concentration. Reasonable agreement between theory and experiment could only be obtained if an effective interaction radius, corresponding to surface asperities on the titania particles, was used in the calculation. High-resolution TEM images suggest that the effective interaction radius corresponds to the size of surface crystallites formed during synthesis.
Publisher: Elsevier BV
Date: 04-2005
Publisher: Elsevier BV
Date: 08-2005
Publisher: Elsevier BV
Date: 06-2008
DOI: 10.1016/J.JCIS.2008.02.072
Abstract: Single bubbles of very pure N2, He, air and CO2 were formed in a quiescent environment in ultra-clean water, with diameters ranging from 10 to 100 mum. Their terminal rise velocities were measured by high-speed video microscopy. For N2, He and air, excellent agreement with the Hadamard-Rybczynski (H-R) equation was observed, indicating that slip was occurring at the liquid-vapor interface. For CO2 bubbles with diameters less than 60 microm, the terminal rise velocities exceeded those predicted by the H-R equation. This effect was ascribed to the enhanced solubility of CO2 compared with the other gases examined. The presence of a diffusion boundary layer may be responsible for the increased terminal velocity of very small CO2 bubbles.
Publisher: Springer Berlin Heidelberg
Date: 2004
DOI: 10.1007/B97077
Publisher: Elsevier BV
Date: 08-2009
Publisher: AIP Publishing
Date: 09-1987
DOI: 10.1063/1.453009
Abstract: The absorption spectra of silver sols in various stages of particle aggregation, as well as the surface-enhanced Raman scattering (SERS) excitation of citrate adsorbed on the colloid particles have been deconvoluted into a set of Gaussian bands. The absorption wavelength variation upon aggregation of the silver sols can be satisfactorily explained using an exciton model and a linear arrangement of the aggregated silver particles. Evidence is presented which shows SERS is only observed from excitation into the absorption bands associated with the aggregated colloid particles. A linear relationship was found to exist between the intensities of the aggregate absorption band and the SERS signal.
Publisher: Elsevier BV
Date: 02-2015
Publisher: Elsevier BV
Date: 07-2023
Publisher: Elsevier BV
Date: 04-1993
Publisher: Elsevier BV
Date: 2001
Publisher: American Chemical Society (ACS)
Date: 28-12-2002
DOI: 10.1021/JP0118221
Publisher: Springer Science and Business Media LLC
Date: 10-2013
Publisher: Royal Society of Chemistry (RSC)
Date: 1990
DOI: 10.1039/FT9908602955
Publisher: Elsevier BV
Date: 05-2006
Publisher: Elsevier BV
Date: 1990
Publisher: Elsevier BV
Date: 06-1995
Publisher: Elsevier BV
Date: 2006
Publisher: Elsevier BV
Date: 03-2006
Publisher: American Chemical Society (ACS)
Date: 25-01-2012
DOI: 10.1021/JP210870V
Publisher: SAGE Publications
Date: 15-04-2019
Abstract: This article outlines a method we call Queer Walking Tours as site-specific research-creation events. It gives a brief overview of the Queer Walking Tours as method and then describes one specific tour that explored the concepts ‘Migration, Militarisms, and Speculative Geology’. Queer Walking Tours offer cultural geography and a range of other disciplines and fields a form of place-based research that draws on Indigenous, anti-racist, feminist, and queer frameworks to open up different conversations around the notion of place.
Publisher: Elsevier BV
Date: 06-2004
Publisher: Elsevier BV
Date: 05-2021
Publisher: Elsevier BV
Date: 05-2009
Publisher: Elsevier BV
Date: 08-2015
Publisher: Elsevier BV
Date: 05-2018
Publisher: American Chemical Society (ACS)
Date: 03-03-2009
DOI: 10.1021/LA803838K
Abstract: The adsorption of a modified polyacrylamide on gold surfaces coated with varying proportions of -CH3- and -OH-terminated alkanethiols (producing substrates of varying hydrophobicity: thetac=75, 98, and 119 degrees), was investigated using quartz crystal microbalance with dissipation (QCM-D), tapping-mode atomic force microscopy (TM-AFM), and captive bubble contact angle measurements. The QCM-D data for the polymer adsorbing on the different substrates indicates that the polymer adsorbs faster and to a greater extent on surfaces with higher hydrophobicity. Dissipation data from the QCM-D suggests that the adsorbed polymer undergoes a conformational change when adsorbing onto the substrates of higher hydrophobicity, forming a less rigid extended layer as the adsorption progresses toward the maximum adsorbed amount. AFM imaging of the adsorbed layer illustrates that the polymer layer is incomplete on all three substrates, and that the underlying substrate hydrophobicity has a role in determining the morphology (distribution, coverage, and thickness) of the adsorbed layer. Contact angle measurements of the polymer-coated substrates show variation in the ability of the polymer to reduce the hydrophobicity of the substrates. The role of coverage and distribution of adsorbed polymer on the surface hydrophobicity reduction is discussed.
Publisher: Wiley
Date: 06-1985
Abstract: Spin-lattice (T1) and spin-spin (T2) relaxation times have been measured on perfused rat hearts under two experimental conditions. T1 exhibits a monoexponential decay. On the other hand T2 has a decay with two components: a short one T2s and a long one T2l. These facts have been discussed according to cross-relaxation and a bicompartmentalization of tissue assuming a slow exchange model for spin-spin relaxation and a fast exchange model for spin-lattice relaxation. Increasing the osmotic pressure of the perfusion solution decreased the absolute density proton of the T2s compartment reflecting the loss of its water content. The paramagnetic ion manganese diminishes the values of T1 and those of the long component T2l without affecting its short component. Therefore the short component could be assigned to intracellular and the long component to extracellular free water. The extracellular T2 (459 ms) is approximatively 10-fold higher than the intracellular T2 (45 ms). With images of "pure T2" such a difference could be useful to enhance the contrast between organs and the surrounding liquid or between organs with different water compartmentalization.
Publisher: American Chemical Society (ACS)
Date: 20-09-2010
DOI: 10.1021/LA101695W
Abstract: The adsorption of carboxymethyl cellulose (CMC) onto a hydrophobic self-assembled monolayer has been characterized using the quartz crystal microbalance (with dissipation monitoring, QCM-D). Adsorption was studied as a function of initial solution conditions. CMC adsorbs to a greater extent at high ionic strength (10(-1) M KCl as opposed to 10(-2) M KCl) or low pH (3 as opposed to 9). The solution conditions that yielded the lowest initial adsorbed amount (10(-2) M KCl, pH 9) were used as a reference to investigate the response of the adsorbed layer to a switch in solution conditions after adsorption (i.e., to higher ionic strength (10(-1) M KCl) or lower pH (pH 3)). The adsorbed layer released significant amounts of hydration water after each solution switch, as determined by the QCM-D measurements. This expulsion of hydration water was fully reversible. For the two solution switches, reducing the solution pH resulted in a more pronounced change in the amount of hydration water within the adsorbed CMC, accompanied by a distinct conformational change, as determined from a QCM D-f plot. In addition to studying adsorption using QCM-D, the effect of adsorbed CMC on surface hydrophobicity has been investigated using captive bubble contact angle measurements. The effect of the polymer on the contact angle of the surface was seen to be greatest when adsorbed at low pH or at higher ionic strength. CMC was also seen to have a significantly enhanced ability to reduce the surface hydrophobicity after both the ionic strength and pH switches, lowering the advancing water contact angle by 6 and 23° and the receding water contact angle by 10 and 40° for the ionic strength and pH switches, respectively. As with the change in hydration water content, the change in the contact angle of the polymer-coated surface following the solution switches was reversible.
Publisher: American Chemical Society (ACS)
Date: 12-07-2011
DOI: 10.1021/JP203714A
Publisher: American Chemical Society (ACS)
Date: 03-2007
DOI: 10.1021/LA062920M
Abstract: Large-scale molecular dynamics simulations are used to model the dewetting of solid surfaces by partially wetting thin liquid films. Two levels of solid-liquid interaction are considered that give rise to large equilibrium contact angles. The initial length and thickness of the films are varied over a wide range at the nanoscale. Spontaneous dewetting is initiated by removing a band of molecules either from each end of the film or from its center. As observed experimentally and in previous simulations, the films recede at an initially constant speed, creating a growing rim of liquid with a constant receding dynamic contact angle. Consistent with the current understanding of wetting dynamics, film recession is faster on the more poorly wetted surface to an extent that cannot be explained solely by the increase in the surface tension driving force. In addition, the rates of recession of the thinnest films are found to increase with decreasing film thickness. These new results imply not only that the mobility of the liquid molecules adjacent to the solid increases with decreasing solid-liquid interactions, but also that the mobility adjacent to the free surface of the film is higher than in the bulk, so that the effective viscosity of the film decreases with thickness.
Publisher: Elsevier BV
Date: 07-2008
DOI: 10.1016/J.JCIS.2008.04.038
Abstract: Although surfactants and particles are often mixed together in emulsions, the contribution of each species to the stabilisation of the oil-water interface is poorly understood. We report the results of investigations into the formation of emulsions from solutions of surfactant in oil and aqueous suspensions of laponite. Depending on the salt concentration in the aqueous suspensions, the laponite dispersed as in idual disc-shaped particles, 30 nm in diameter, or flocculated into aggregates tens of micrometres in diameter. At the concentrations studied, the flocculated particles alone stabilized oil-in-water emulsions. Synergistic interactions between the particles and octadecylamine at the oil-water interface reduced the average emulsion drop size, while antagonistic interactions with octadecanoic acid enhanced coalescence processes in the emulsions. The state of particle dispersion had dramatic effects on the emulsions formed. Measurements of the oil-water interfacial tension revealed the origins of the interactions between the surfactants and particles.
Publisher: Elsevier BV
Date: 10-2007
Publisher: Elsevier BV
Date: 07-1997
Publisher: Elsevier BV
Date: 2015
Publisher: Elsevier BV
Date: 09-2005
Publisher: American Chemical Society (ACS)
Date: 11-03-2003
DOI: 10.1021/JP021751L
Publisher: Elsevier BV
Date: 05-1994
Publisher: Elsevier BV
Date: 05-2010
DOI: 10.1016/J.JCIS.2010.01.075
Abstract: The adsorption of three dextrin-based polymers, regular wheat dextrin (Dextrin TY), phenyl succinate dextrin (PS Dextrin), and styrene oxide dextrin (SO Dextrin) on a model hydrophobic surface, consisting of a mixed alkanethiol layer on gold, has been characterized using the quartz crystal microbalance with dissipation monitoring (QCM-D). The three polymers exhibited varying affinities and capacity for adsorption on the hydrophobic substrate. Atomic force microscope (AFM) imaging of the polymer layers indicates that all three polymers fully cover the surface. The effect of the three polymers on the static contact angle of the surface was studied using captive bubble contact angle measurements. The three polymers were seen to reduce the receding contact angle by similar amounts (approximately 14°) in spite of having varying adsorbed amounts and differences in adsorbed layer water content. Although no differences were observed in the ability of the polymers to reduce the static contact angle, measurements of the dynamic contact angle between a rising air bubble and the polymer covered substrate yielded stark differences between the polymers, with one polymer (SO Dextrin) slowing the dewetting by an order of magnitude more than the other two polymers. The differences in dewetting behavior correlate with the adsorbed layer characteristics determined by QCM-D and AFM. The role of the dynamic and static contact angle in the performance of a polymer as depressant is discussed.
Publisher: Elsevier BV
Date: 07-2011
Publisher: Royal Society of Chemistry (RSC)
Date: 2007
DOI: 10.1039/B709624K
Abstract: The kinetics of adsorption of CO(2) molecules dissolved in aqueous solution onto a hydrophobised silica surface were investigated using a quartz crystal microbalance (QCM). The results of this investigation were compared with those obtained earlier from tapping mode atomic force microscopy (TMAFM) under the same experimental conditions (J. Yang, J. Duan, D. Fornasiero, J. Ralston, J. Phys. Chem. B., 2003, 107(25), 6139-6147 ref. 1). The QCM results represent the early stage of CO(2) gas adsorption (<20 min), before CO(2) gas bubbles adsorbed on the surface can be directly observed by TMAFM. The QCM results confirmed our observation from TMAFM imaging: that CO(2) gas molecules present in solution only adsorb on silica when its surface is hydrophobic. More importantly, the results showed that gas adsorption/bubble growth undergoes two consecutive kinetic processes: a slow and a fast adsorption process.
Publisher: Elsevier BV
Date: 11-2002
Publisher: Elsevier BV
Date: 1991
Publisher: Elsevier BV
Date: 09-2011
DOI: 10.1016/J.JCIS.2011.05.046
Abstract: This work reports on coalescence in oil-in-water Pickering emulsions subjected to simple shear flow. The emulsions were stabilized by silanized fumed silica particles forming layers a few hundred nanometers thick around drops that are tens of micrometers in size. The drop size and particle concentration in the emulsions were fixed, while the salt concentration was varied to adjust the colloidal interactions between the drops and particles. At rest the oil drops do not coalesce. The susceptibility of the drops to orthokinetic coalescence was found to depend on the extent of particle flocculation in the attached particle layer. The evolution of the drop size with time and shear rate was consistent with phenomenological models used to describe the behavior of emulsions under shear.
Publisher: Elsevier BV
Date: 08-2017
Publisher: Royal Society of Chemistry (RSC)
Date: 1998
DOI: 10.1039/A801144C
Publisher: Elsevier BV
Date: 09-2001
Publisher: Royal Society of Chemistry (RSC)
Date: 1986
DOI: 10.1039/F29868200015
Publisher: Informa UK Limited
Date: 27-10-2020
Publisher: Elsevier BV
Date: 06-2003
Publisher: Elsevier BV
Date: 06-1994
Publisher: American Chemical Society (ACS)
Date: 13-05-1999
DOI: 10.1021/LA981526O
Publisher: Elsevier BV
Date: 08-2010
DOI: 10.1016/J.JCIS.2010.04.073
Abstract: The foamability of a triblock copolymer solution was strongly influenced by the presence of particles. The stability of the foam was evaluated by measuring the foam volume, the drainage of water and particles, and the bubble size as a function of time. The higher stability of foams produced with hydrophilic quartz particles, compared with hydrophobic graphite particles, was related to the presence of quartz aggregates in the lamellae and Plateau borders reducing water drainage, and therefore thin film rupture and bubble coalescence. The copolymer adsorbed slightly more on the hydrophobic graphite, causing the particles to disperse and drain, with the water out of the foam, whereas the hydrophilic quartz aggregated and remain in the lamellar and Plateau borders of the foam.
Publisher: Elsevier BV
Date: 11-2008
DOI: 10.1016/J.COLSURFB.2008.08.002
Abstract: A combination of complementary analytical techniques has provided valuable information on the physicochemical properties of lipid-DNA complexes such as their size, shape, structure and surface charge. The experimental conditions for producing small and stable lipid-DNA complexes were determined. These complexes consist of spherical primary particles of approximately 60 nm in diameter connected to each other by DNA strands to form small clusters of approximately 70-200 nm in diameter. At high salt concentrations these complexes were not stable and aggregated. Several methods were used to stabilise the lipid-DNA complexes at physiological salt concentrations.
Publisher: Elsevier BV
Date: 09-2003
Publisher: Elsevier BV
Date: 09-2019
Publisher: Elsevier BV
Date: 1986
DOI: 10.1016/0883-2897(86)90133-9
Abstract: The myocardial imaging agent technetium-99m-hexakis (tertiarybutylisonitrile) (99mTc-TBI) was prepared by the reaction of [99mTc]pertechnetate with TBI in 50% ethanol/0.9% saline at 100 degrees C, using stannous chloride as the reducing agent. A study of the reaction parameters enabled the yield to be optimized to better than 90%, although this was reduced to approximately 60% if a purification step was carried out. Chromatographic analysis on ITLC-SG medium showed the final product to be of high radiochemical purity. Biological studies comprising biodistribution in mice over a 2-h period, imaging studies in animals and sub-acute toxicity testing in mice indicated that 99mTc-TBI prepared as here described is a suitable agent for routine clinical use in humans.
Publisher: Elsevier BV
Date: 09-2006
DOI: 10.1016/J.JCIS.2006.04.071
Abstract: Very small bubbles which partially coat the surface of particles influence whether or not heterocoagulation between a particle and a bubble occurs. The electrostatic and van der Waals forces of interaction between particles and bubbles were calculated as a function of electrolyte concentration, particle size, and the size and distributions of these very small bubbles present on the particle surface. The height of the surface force barrier was compared with the hydrodynamic pressing force under conditions of flotation. The presence of these very small bubbles has a profound effect on the interaction between particles and bubbles and, in particular, strongly decreases the critical particle radius for heterocoagulation.
Publisher: Elsevier BV
Date: 11-2014
Publisher: Elsevier BV
Date: 08-2020
Publisher: Elsevier BV
Date: 2016
Publisher: Springer Science and Business Media LLC
Date: 1994
Publisher: Elsevier BV
Date: 08-2010
Publisher: Elsevier BV
Date: 08-1987
Publisher: Springer Science and Business Media LLC
Date: 10-2006
Publisher: IOP Publishing
Date: 07-2017
Publisher: Elsevier BV
Date: 11-2001
Publisher: Elsevier BV
Date: 05-2002
Publisher: Elsevier BV
Date: 06-2003
Publisher: Informa UK Limited
Date: 23-07-2020
Publisher: Elsevier BV
Date: 06-1992
Publisher: Elsevier BV
Date: 1999
Publisher: Royal Society of Chemistry (RSC)
Date: 1999
DOI: 10.1039/A900977I
Publisher: Elsevier BV
Date: 03-2003
Publisher: Elsevier BV
Date: 04-2010
No related grants have been discovered for Daniel Fornasiero.