Natural-synthetic hydrid biomaterials have been isolated from the growth of Alcaligenes latus and Pseudomonas oleovorans in the presence of diethylene glycol (DEG). A. latus could cometabolise DEG with 10 g/L glucose, while DEG was consumed by P. oleovorans with 20 mM sodium octanoate or octanoic acid. The presence of DEG in bioprocessing systems for the production of short chain length (scl-) and medium chain length (mcl-) PHAs consequently lowered cell viability and PHA yield. Cell morphology was slightly changed, but the PHA inclusion bodies apparently were not. DEG affected the composition of the mclPHA which was confirmed to be polyhydroxyoctanoate (PHO) with a significant increase in the C8 component. Gas chromatography-mass spectrometry (GC-MS) was used to quantitatively monitor DEG in the system and revealed its cellular adsorption. Intracellularly, the DEG significantly decreased the molar weight of the mclPHA and sclPHA. P1PH NMR, 2-D COSY and HSQC spectra confirmed that the polymer samples consisted of PHA chains terminated by DEG. Similar to the cultivation of P. oleovorans with DEG, the presence of PEG200 and PEG400 also had an effect on cell growth, PHO yield and cell viability. Furthermore, a hybrid copolymer of PHO-PEG200 was synthesised. The synthesis of these natural-synthetic hybrid copolymers could lead the way for a wide variety of PHA-PEG copolymers with a range of bioactive properties. All thermal properties of PHB were higher than those of PHB-DEG. This may be due to a combination of lower PHB molecular weight and termination of the chains by DEG, i.e. ???DEGylation???. However, PHB-DEG was more elastomeric when compared to PHB, showing properties similar to its copolymer with 20 mol% 3-hydroxyvalerate. Contact angles revealed that the PHB-DEG film was slightly more hydrophilic than PHB. Despite the large difference in their respective proportions, the comparatively small DEG component exerted an influence on chain confirmation, such that solvent casting under humid conditions apparently induced self-assembly and formed a disordered microporous film. DEGylation of PHO also had noticeable effects on the physiochemical properties of the biopolymer. A major decrease in molecular weight, together with the termination of hydrophobic PHO chains with hydrophilic end-groups resulted in changes to its thermal properties when compared to PHO. In comparison to PHO, solvent cast films of PHO-DEG were apparently less flexible, but more hydrophilic.

The work presented in this thesis represents a combination of laboratory and field experiments designed to explain some field observations I made on some coarse sands in South Australia in 1999: that much of the irrigation water and nutrients applied to the sands under drip-irrigation simply passed through the root zone leaving the crops water-stressed shortly after irrigation events. There was clearly only minimal lateral spread of the water in these coarse sands. However, by applying small concentrations of polyacrylamide or ‘PAM’ in the irrigation water, the crops seemed to do better. Furthermore the timing of irrigation events appeared to be more flexible on the PAM-treated properties. I found this intriguing and saw an opportunity to increase the lateral spread of water in the root zone and thereby increasing the stored volume and residence time of water. By retaining more water in the rootzone, there was potential to save a considerable amount of costly irrigation water, and also improve crop production and quality. With encouragement from my then employer (Elders Pty Ltd) and from Ciba Specialty Chemicals Australia, I undertook to explore my findings in greater detail and to attempt to explain them based on some ‘hard’ (experimental) evidence. Increasing the lateral spread of water under drippers in coarse-textured soils requires water to be retained in the root zone for longer periods during irrigation, but the practical methods for doing this are limited to: • Altering the pore size distribution to create a finer average range of pore sizes, either by compaction or by stabilization of smaller pores using organic matter or additions of clay. • Reducing the wettability of the soil so that less water can be taken in and the soil never becomes saturated. (This of course risks surface runoff and suboptimal placement of irrigation water). • Altering the physical properties of irrigation water (eg. viscosity, surface tension) so that it interacts differently with soil pores and moves through them more slowly. The aim of the research was therefore to evaluate the potential for some commercially available PAMs to reduce hydraulic conductivity and to increase water retention on some drip-irrigated coarse sandy soils of South Australia and Victoria. I worked with two commonly available anionic polyacrylamides, designated PAM-1011 and PAM-135, and measured ponded infiltration in laboratory columns of seven different sandy soils from around South Australia and Victoria. I varied the concentration of the polymer within the range typically used in the field (0, 1 and 10 ppm for PAM-1011; 0, 2.5 and 25 ppm for PAM-135) and I also varied the quality of the irrigation water used to mix the PAM solutions in terms of salinity and sodicity (distilled water, 10 and 20 mmol(+) salt/L, using either sodium chloride, calcium chloride, or both). I measured the effects of PAM on pore-size distribution of one of the sands (by the water retention characteristic), on water repellence of the soils (by measuring water droplet penetration times), and the kinematic viscosity of the PAM solutions at various concentrations with various qualities of irrigation water. I also set up transparent cases of sand to observe infiltration and wetting behaviour of the PAM solution. Finally, with some understanding of how the physical and chemical properties of the PAMs, I conducted a field trial to measure the soil water matric potential at various depths and locations around drippers in vine rows receiving PAM in the irrigation water. Laboratory findings: The polymer PAM-1011 significantly reduced the steady-state infiltration rate in all sands, and it did this with relatively modest concentrations (< 10 ppm). The polyacrylamide PAM-135 was not effective for this purpose, which indicated that the chemical properties of the polymer (not investigated here) influenced its physical behaviour. Further work with PAM-135 was therefore discontinued in favour of PAM-1011. The effectiveness of PAM-1011 in reducing steady-state infiltration rates was related to changes in the properties of the irrigating solution caused by PAM-1011 rather than by a change in the properties of the soils to which it is applied. For example, PAM-1011 had only minimal (if any) influence on the pore size distribution (water retention) of a coarse sandy soil and had no significant impact on water repellence (wettability) of another sandy soil. It did, however, have a large impact on the kinematic viscosity of the irrigating solution, and the more PAM-1011 that was dissolved, the more viscous the solutions became. The effectiveness of PAM-1011 in reducing steady-state infiltration rates was reduced in salty irrigation water, and there was evidence to suggest that cation-effects may have been involved. When PAM-1011 was dissolved in distilled water, infiltration rates were reduced by the greatest amount. When PAM-1011 was dissolved in salty water containing the monovalent cation, sodium, infiltration rates were not reduced as much; furthermore, if the solvent water contained the divalent cation, calcium, PAM-1011 was even less effective than in sodium-rich water. Thus electrolytes affected the physical conformation of PAM-1011 solutions, altering viscosity. To overcome the salt-water effects, higher concentrations of PAM-1011 needed to be used. The cation-effects were primarily related to the way each cation interacted with the polymer to alter its kinematic viscosity. PAM-1011 in distilled water had the greatest viscosity, while PAM-1011 in sodium-rich water had a lower viscosity, and PAM-1011 in calcium-rich water had the lowest viscosity. A practical implication from this is that irrigators using salty waters will need to dissolve more PAM-1011 in their water-sources to increase the viscosity and thus gain the retarding effects of the polymer on infiltration rates. The data suggest that the amount of polymer required to overcome the salt effects is about 10 ppm PAM-1011. Rates as low as 1 ppm can be used when irrigators have access to high-quality water with < 10 mmol(+) salt/L present. Visual observations of the wetting fronts during infiltration showed that irrigation water containing PAM-1011 at between 1 and 10 ppm reduced the depth of percolation and increased its lateral spread in coarse sands. Field study: The field work was largely unsuccessful because shortly after the treatments were applied, a 1-in-100 year hailstorm struck that completely wiped out the vegetation on the vines in the study. I spent most of the season simply trying to keep the vines alive and to recover some of the leaf area for future years. Overall, however, this work identified the ability of PAM-1011 to reduce water movement through the root zone of coarse sands, and demonstrates the potential to conserve a great deal of water – a significant move toward higher water- and nutrient-use efficiencies on the coarser textured soils in the Murray-Darling Basin. / Thesis (M.App.Sc.) -- University of Adelaide, School of Earth and Environmental Sciences, 2007

Typescript (photocopy) / 122 leaves, [7] leaves of plates : ill. ; 27 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.) Dept. of Physics, University of Adelaide, 1977

Graduation date: 1974

A phase sensitive measurement technique that permits the simultaneous determination of two independent thermal properties of thin dielectric films is presented. Applying the technique results in a film's thermal diffusivity and effusivity, from which the thermal conductivity and specific heat can be calculated. The technique involves measuring a specimen's front surface temperature response to a periodic heating signal. The heating signal is produced by passing current through a thin layer of nichrome that is deposited on the specimen's surface, and the temperature response is measured with a HgCdTe infrared detector operating at 77 K. The signal that is produced by the infrared detector is first conditioned, and then sent to a lock-in amplifier. The lock-in is used to extract the phase shift present between the temperature and heating signal through a frequency range of 500 Hz-20 kHz. The corresponding phase data is fit to an analytical model using thermal diffusivity and effusivity as fitting parameters. The method has been applied effectively to 1.72 ��m films of Si0��� that have been thermally grown on a silicon substrate. Thermal properties have been obtained through a temperature range of 25��C-300��C. One unanticipated outcome stemming from analysis of the experimental data is the ability to extract both the thermal conductivity and specific heat of a thin film from phase information alone, with no need for signal magnitude. This improves the overall utility of the measurement process and provides a 'clean', direct path with fewer assumptions between data and final results. The thermal properties determined so far with this method are consistent with past work on Si0��� films. / Graduation date: 1998

Zirconium press plates have been developed for the production of melamine coated particle board, using shot-peening to achieve the desired plate (and therefore coated particle board) surface texture. Service temperatures of the press plates approach 200��C. This study examined the microstructural effects of extended exposure of shot-peened zirconium to temperatures of 200��C and 300��C. Softening of the surface may reduce wear resistance and possibly the surface morphology of the plate, affecting the usability of the plates. It was discovered that the shot-peened surface of the plates experienced a loss in hardness from approximately 230 VHN (DPH) to about 220 VHN after 560 hrs at 200��C. The same drop in hardness was experienced after only 5.5 hrs at 300��C. This decrease in hardness was determined from hardness profiles before and after heat treating the zirconium to various times from 0.5 hours to 4458 hrs and 2790 hrs at 200��C and 300��C respectively. The decrease in hardness is believed to be a result of static recovery, the annihilation of point and/or line defects and/or alignment of dislocations into relatively low misorientation substantially relatively close to the shot-peened surface (about 35 ��m), and decreased more modestly over the next 100 ��m until virtually no drop was experienced further than approximately 150 ��m from the surface. The shot-peening hardens the surface region which extends about 150 ��m from the surface. Thus, the level of recovery appears to depend on the stored energy associated with cold work, or ambient temperature deformation. This increases from about 2-3% cold work (equivalent percent cold reduction from rolling) in the bulk of the specimens to near 99% at the surface resulting from shot-peening. The dislocation structure of the shot-peened zirconium was examined in the as-peened as well as the annealed conditions using transmission electron microscopy. / Graduation date: 1997

The clay mineral composition of sediments deposited in the last six oxygen isotope stages in the Gulf of Mexico continental slope was characterized. Smectite and illite were found to be the two major clay minerals of the clay fraction while kaolinite, chlorite and quartz were present in the clay fraction but in less proportions. Variations in clay mineral abundances, especially in the relative abundances of smectite and illite, were identified in relation to climate changes. Smectite was the most abundant mineral in sediments of the current (stage 1) and last interglacial maxima (stage 5) while illite dominates the clay min-eralogy of sediments from the last glacial maximum (stage 2). Relationships between clay mineralogy and physical properties were investigated as well. Significant positive correla-tions were found between Atterberg limits with the smectite content of the bulk sediment and with clay content. However, the relationship with smectite yielded a significantly higher correlation coefficient. Smectite and clay content also affect the natural water con-tent of sediments and its changes with depth.

No description available.

Two Texas fed beef and cow/bull packing plants were surveyed for high pH beef carcasses as well as the evaluation of functional properties of high pH beef in whole muscle beef jerky, frankfurters, and snack stick production. An estimated 42% of cow carcasses were of 6.0 muscle pH or greater as well as exhibiting darker, less red colored lean. Jerky high in pH from cow inside rounds resulted in the greatest percent moisture and least percent protein compared to other treatments. High pH cooked jerky were higher in (P < 0.05) pH and water activity and lower in percent fat and shear force values. In cooked jerky slices, fed-high resulted in the highest percent MPR and cook yield, but was the most tender. In contrast, fed-normal resulted in the least water activity, MPR and toughest jerky slices. In frankfurter production, emulsion stability and hydration values was highest for C (1.98mL) followed by 100H (3.37mL) that decreased as percent high pH decreased. As storage day increased, frankfurter pH decreased, especially by day 56 (5.67) where LAB and APC counts had reached a log of 6.0 indicative of spoilage by day 28 and became lighter and less red in color with minimal lipid oxidation. 100H was harder and less cohesive with trained panelists reported containing at least 50% high pH meat was harder. The pH and internal color of cooked snack sticks significantly increased and became lighter and redder as percent high pH meat increased. Even though water activity compared to a whole muscle dry product or an emulsified, water added product ranged from 0.85 to 0.86 (P > 0.05), minimal (P greater than 0.05) lipid oxidation occurred. 100N resulted in the least percentage of fat but 3% more (P less than 0.05) protein and highest shear force values. Overall, beef raw materials high in pH may be better suited in a semi-dry fermented product.

Cadmium sulfide (CdS) thin films are very attractive materials due to their tunable optical properties and potential applications in not only photovoltaic devices but also in electronics, bio-labeling and fluorescence imaging. Recently, there is a great interest in flexible photovoltaic devices due to their unique properties such as very low weight, mechanical durability and large area applications. Organic semiconductors and their heterojunctions with inorganic materials are the most promising candidates for flexible photovoltaic applications. Preparation of CdS and Polypyrrole (PPy) semiconducting thin films on flexible polyethyleneterephtalate (PET) substrates and investigation of their morphological, structural, optical and electrical properties are the main scopes of this thesis. In the first part of the study, CdS thin films were deposited on PET via electrodeposition method. Taking the advantages of electrodeposition methods, CdS thin films with good optical and electrical properties were produced. CdS thin films were also deposited on soda-lime glass substrates in order to observe substrate effect. Scanning electron microscopy equipped with energy dispersive X-ray (SEM-EDX), X-ray diffraction (XRD) and UV-vis spectrometry have been used to determine the structural and optical properties of the films deposited at various temperatures and for different deposition time intervals. For all samples, molecularly homogenous CdS films have been observed with atomic percent ratios of the Cd to S very close to 1:1. Thin films showed (002) hexagonal crystal structure around 26 (2) with average grain size 7.0 nm. CdS films have high transmittance for the wavelength greater than 500nm. Band gap energies of the films, which range between 2.74 and 2.68 eV, decreased with increasing both deposition temperature and time. For further characterization, photoelectrochemical performances and electrochemical impedance spectroscopy (EIS) of both as deposited and CuCl2 treated CdS thin films have been investigated. Later, following to the deposition of individual CdS thin films, polypyrrole thin films were produced and then heterojunctions of polypyrrole with CdS were examined. It has been observed that cadmium sulfide enhanced the photoelectrochemical properties of the polypyrrole film. Influence of the polypyrrole thin film deposition time on the photoelectrochemical properties has been also investigated in this study. Frequency dependent measurements revealed that type of charge carrier changes as a function of polypyrrole deposition time.