Mechanically separated turkey meat (MSTM) is one of the cheapest sources of protein; however its use for production of further-processed poultry products is limited due to undesirable composition. pH-shifting extraction was applied to overcome the problems associated with MSTM. In the first study the effect of acid pH-shifting extraction with the aid of citric acid and calcium ions on lipids and heme pigments removal from MSTM was investigated. The maximum removal of total, neutral and polar lipids was achieved with addition of 4, 6 and 2 mmol/L of citric acid, respectively. Addition of 6 or 8 mmol/L of citric acid was the most efficient for total heme pigments removal. In the second and third studies chemical, functional and rheological properties of proteins isolated from MSTM were investigated as influenced by different (2.5, 3.5, 10.5 and 11.5) extraction pH. Gel-forming ability was found the highest for pH 3.5 extracted protein. / Food Science and Technology

The objective of this Thesis is to devise a system for the "rheology-based design" of non-settling (homogeneous) slurry pipelines that is more conducive to application by practicing engineers without impairing its accuracy or utility for research purposes. The cornerstone is the development of a new rheological model and constitutive equation for homogeneous slurry based on the aggregation/deaggregation of the suspended mineral particles. This “yield plastic” model is shown to describe a family of models that includes the Newtonian, Bingham plastic and Casson models as special cases. It also closely approximates the results of many consistency models, including power law, yield power law, Cross and Carreau-Yasuda. The yield plastic model is then used to develop design equations to determine the pressure-gradient of laminar and turbulent pipe flow. A relative energy dissipation criterion is proposed for the laminar-turbulent transition and shown to be consistent with currently used transition models for Newtonian and Bingham fluids. Finally, a new dimensionless group (the “stress number”) is proposed that is directly proportional to the pressure-gradient and independent of the velocity. When the design equations are presented graphically in terms of the stress number and the plastic Reynolds number, the resulting “design curve diagram” is shown to be a dimensionless (pressure-gradient vs. velocity) pipe flow curve. The net result is that the hydraulic design of homogeneous slurry systems only requires the use of a single constitutive equation and three engineering design equations. The results are presented in a conceptually easy form that will foster an intuitive understanding of non-Newtonian pipe flow. This will assist engineers to understand the impact of slurry rheology when designing, operating and troubleshooting slurry pipelines and, in the future, other slurry related processes.

A systematic research study was carried out in order to characterize the rheology of concentrated slurries prepared from eight nickel laterites. The experiments were carried out using a rotational viscometer, and the behavior of the laterites was evaluated in terms of the apparent viscosity and yield stress obtained through flow curve modeling. An attempt was made to correlate the results obtained for the laterite samples with data obtained for model single mineral systems as well as for model mixed mineral systems. In combination with detailed mineralogical characterization of the laterite samples, all the rheological results allowed a rheology-based laterite classification system to be proposed. Accordingly, the laterite samples gave the following responses: the SAPSIL samples (high-quartz) generally producedl ow yield stress values, the SAPFE samples (high-iron) were characterized by intermediate to high yield stress values, while the SAP samples (saprolite) gave the highest yield stress values. Interestingly, these dominant rheological responses of laterites could actually be predicted based on rheological tests carried out on model mineral suspensions (particularly goethite and quartz). Since the rheology of fine mineral suspensions is largely determined by the surface properties (surface charge) of the particles, a series of electro-acoustic measurements were also performed on model minerals and laterite samples to analyze the surface charge characteristics of the tested samples. It was demonstrated that the current electro-acoustic theory developed for single mineral systems can readily be used for modeling the behavior of mixed mineral systems. The modeling and experimental data agreed exceptionally well when constituent minerals were of the same surface charge under given pH. Clear but rather small deviations between experiment and theory were observed under conditions when the minerals were oppositely charged. This observation strongly suggested that inter-particle aggregation was most likely responsible for the observed discrepancies. Overall, the results of this thesis show that laterite slurries exhibit a wide range of rheological responses due to highly variable mineralogy, differences in particle size distributions, and difference in the surface properties of the many constituent minerals. It also shows that the surface properties of the minerals relates to rheology.

Linear Low Density Polyethylene (LLDPE) is a relatively new plastic that is becoming widely used in many applications. In fact the production rate of LLDPE is vital in determining the process characteristics and subsequent properties of the end products. In this work we have examined, specifically, the influence of surfaces and structure on the rheology and processing properties of LLDPE. A review of the effect of surfaces on the rheology and processing of polymers is given, with particular emphasis on the interaction between metals and polymers. The influence of oxidative degradation and radiation on the structural modification of polymers is also reviewed. Standard rheological characterisation tests determined there was no effect of various metal and teflon surfaces on the rheology of LLDPE. There was also no evidence of wall slip on metal or teflon surfaces. The generalised Maxwell model (with Wagner's damping function) predicted dynamic and steady shear properties at standard characterisation rates well. The effects of degradation of LLDPE were quantified, and an increase in elasticity due to increased crosslinking of long polymer chains was noted during degradation tests. This effect increased with time (after a degradation time) and temperature. There was no effect of metals on the degradation properties of LLDPE, however, there was evidence of increased carbon-oxygen species (or increased oxidation) at the metal/LLDPE interface for metals containing copper at the interface (copper and brass). The migration of copper was facilitated by the low heat of formation of the oxides on the copper-containing metals. Increasing gamma and ion beam radiation dose decreased melting temperatures, heats of melting and crystallinity due to increased crosslinking at the crystallite surfaces and the reduction in crystal sizes. Gel fraction and tightness of gel increased with radiation dose due to increased crosslinking. Increased radiation dose also increased the elasticity and flow resistance of the samples as shown by rheological tests. The extension of a power law representation of the relaxation modulus of irradiated samples was extended to predict stress build-up and relaxation properties in steady shear tests. There was little effect of type of radiation (gamma or ion beam) on physical and rheological properties. However, there was a marked increase in the effects of irradiation in the melt (150degC) on the physical and rheological properties of LLDPE, which was due to the increased effective amorphous nature of the sample in the melt. The equivalence of the effects of degradation and irradiation are discussed. Viscosity was well predicted by the generalised Maxwell model (with Wagner's damping function) at processing rates. The normal stress differences calculated by Boger and Denn's model correlated well with this generalised Maxwell model, which was due to the inclusion of a flow rearrangement term. There was a marked increase in exit pressures, exit losses, flow rearrangement length, flow singularity, and exit stresses for flow over brass inserts at the die exit. These effects coincided with the production of a porous, copper-rich brass surface and it was postulated that this was the results of surface dezincification which caused increased adhesion between the LLDPE and the brass via physical interlocking at the porous surface. Extension of these results to melt fracture are discussed.

Thesis (M.S.)--University of Delaware, 2007. / Principal faculty advisor: Kausik Sarkar, Dept. of Mechanical Engineering. Includes bibliographical references.

Thesis (PhD) - Swinburne University of Technology, School of Information Technology, Centre for Molecular Simulation - 2005. / A thesis submitted in fulfilment of requirements for the degree of Doctor of Philosophy, Centre for Molecular Simulation, School of Information Technology, Swinburne University of Technology - 2005. Typescript. Bibliography: p. 164-170.

Thesis (M.Ch.E.)--University of Delaware, 2008. / Principal faculty advisors: Norman J. Wagner, Dept. of Chemical Engineering; and Eric W. Kaler, College of Engineering. Includes bibliographical references.

Thesis (Ph. D.)--University of California, San Diego, 1997. / Vita. Includes bibliographical references.

Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2007. / Includes bibliographical references. Also available online.

Thesis (M.S.)--West Virginia University, 1998. / Title from document title page. "October 1998." Document formatted into pages; contains viii, 80 p. : ill. Includes abstract. Includes bibliographical references (p. 78-80).