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Ecotoxicological studies of tributyltin (TBT), using indicatoe species Nucella lapillus (L.)Spence, S. K. January 1989 (has links)
No description available.
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The luminescence of a soyabean oil alkyd resin and the application of luminescence as a discriminating techniqueAllen, Timothy J. January 1995 (has links)
No description available.
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Carbonic anhydrase in marine organismsMudge, Stephen Michael January 1986 (has links)
No description available.
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Structure-property relationships in speciality multicomponent polymers for surface coatings applicationsIbbitson, D. January 1988 (has links)
No description available.
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The levels and effects on tin and copper on shellfish from Strangford Lough, Co. DownBoal, Deborah Catherine January 1990 (has links)
No description available.
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Polyfluorinated acrylates as antifoulantsStone, Maureen January 1999 (has links)
No description available.
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Examination of the surface and interfacial properties of an epoxide-urethane resin for surface coatingsCarpenter, Phillip P. January 1997 (has links)
Electrodepositable paints are used in the auto industry to provide the majority of the protection against corrosion to mild steel car body shells. They are generally epoxy/blocked isocyanate resins systems which are applied by action of an electropotential between the car and an anode. Upon heating to 175°C the blocked isocyanate deblocks, and crosslinking occurs predominantly via the formation of urethane and urea linkages. The aim of the project was to gain a better understanding of the factors which may affect the adhesion of the electrocoat resin polymer to a steel surface, to investigate possible replacements for the tin catalyst currently used, and to develop a quantitative mechanical test for paint adhesion. This was achieved by employing various analytical techniques including Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and mechanical testing.
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Flocculation of wastewater from the production of low voc paintsGina, Dumisa Cornelius 14 May 2008 (has links)
Abstract
This dissertation describes a study of the treatment of wastewater using the
flocculation process. Wastewater samples from Barloworld Plascon paints were
used for the research.
Environmental pressure has necessitated the introduction of a new generation of
low-solvent paints. The behaviour of these in coagulation and flocculation
treatment processes has not been investigated previously. The optimum
flocculent dosage for these paints was investigated. It was found that for paint
wastewater to be flocculated, the effect of the dispersants needs to be
counteracted, which destabilizes the colloidal suspension, enabling flocculation
and settling to occur. Results showed a correlation between the solid content of
wastewater and flocculent dosage.
Changes in redox potential have been found to be associated with good
flocculation. In this work, redox potential was evaluated as an indicator for
destabilisation of the dispersants. It was shown that redox potential can be used
as an indicator of good flocculation at low dispersant concentrations. Owing to
the importance of the hydrolysis reactions of Al3+ in flocculation, which are
affected by pH, the pH range in which good flocculation occurs was determined.
Results show that optimal flocculation occurred between pH 4 and 5.
A strong relationship between flocculent dosage and particle nucleation and
growth was observed. Results also showed that mixing improves flocculation
kinetics.
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Polymeric interactions in tablet coating filmsSakellariou, P. January 1984 (has links)
The objective of this work was the investigation of the polymeric interactions in tablet coating films in relation with effective film formulations. The polymeric interactions were studied by means of torsional braid analysis. For this purpose an existing torsional braid analyser was improved and successfully interfaced to a microprocessor for data acquisition and reduction. Discussion on the contribution of the substrate to the thermomechanical spectra of the TBA as well as factors associated with the optimisation of the technique are presented. The dynamic mechanical behaviour of EC, HPMC, HPMCP-HP50, HPMCP-HP55, HPC and CAP film formers was studied with particular attention to structure- Tg relationship. The plasticisation of two of the most common film formers, namely EC and HPMC, with a series of polyethylene glycols was investigated. It was shown that PEGs efficiently plasticise HPMC, whereas they exhibited limited interactions with EC. The relation of the plasticising efficiency to the size and concentration of the PEGs with respect to the optimisation of the tablet coating formulation is also discussed. The thermomechanical behaviour of blends of EC with water-/pH-dependent film formers was also studied with TBA, in conjunction with the requirements for controlled release coatings. All polyblends exhibited phase separation and the required domain morphology, which was shown capable of retaining small amounts of water-/pH-dependent components even after prolonged leaching. Moreover, the modification of the thermomechanical performance of 80/20 w/w EC/HPMC blends plasticised with PEG200 and PEG400 was investigated. These studies indicated diffusion of the plasticisers into both phases. Finally, the effects of blend composition and interactions in terms of efficient sustained release coatings are identified and discussed.
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Deformation of hard coatings on softer substratesElliott, David Mark January 1991 (has links)
No description available.
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