Study on Performance Characteristics of Interior Permanent Magnet Synchronous Motor Due to Rotor Configuration

This research study was conducted in an effort to understand what effects the rotor configuration has on the performance of a permanent magnet synchronous machine, independent of the stator configuration. Three motors were designed with different interior permanent magnet rotor configurations with the same stator laminations and were analyzed using a combination FEA dq -axis circuit model. The results show that the performance characteristics affected by the rotor configuration were synchronous and reluctance torque production, torque ripple, efficiency and parameter variation. The V-shaped rotor configuration produced the most torque at 70 Nm. The Flat rotor configuration had the second highest torque production at 67 Nm. The Radial rotor configuration had the highest efficiency but had the highest torque ripple. The parameter variation had an effect on the reluctance torque production capabilities of each rotor configuration due to the saturation in the machines

Characterization of HIV-1 Integrase Reactions with Viral DNA

HIV-1 integrase (integrase) catalyzes the insertion of viral DNA into human chromosomes and is a focus for development of anti-integrase inhibitors to combat HIV infection. Integrase catalyzes two steps, a DNA-end cleavage reaction (3’-processing), and a DNA-end joining reaction (strand transfer). Together, these steps result in viral DNA integration into the genome of the host cell, resulting in persistent infection. Better understanding of the mechanism of integration and interactions of the viral and host DNA with integrase are required for optimal inhibitor development. Recombinant integrase protein was purified and activity was evaluated in a biochemistry assay under bulk conditions to optimize 3’-processing and strand transfer activity. Integrase binding to DNA was then measured under these conditions, using quartz crystal microbalance. This technique will also be used to characterize the disruption of integrase binding to DNA by inhibitors. Finally, integrase/DNA complexes will be visualized by atomic force microscopy to explore their interaction. This study addresses gaps in knowledge of viral DNA and HIV-1 integrase interactions as well as the effects of inhibitors on DNA binding.https://scholarscompass.vcu.edu/uresposters/1006/thumbnail.jp

The informational content of subjective expectations for health service use.

BackgroundThis study aims to evaluate the informational content of people's subjective probability expectations for using various health services.MethodsUsing a sample of 1,528 Australian adults (25-64 years), I compared stated probabilities of visiting various health service providers (hospitals, dentists, optometrists, physiotherapists and related care providers, naturopaths and massage therapists) with past utilization and with predicted utilization estimated out-of-sample. I also estimated whether past utilization and subjective expectations were predicted by the same covariates. Finally, I estimated whether subjective expectations had predictive power for the choice to purchase private health insurance conditional on past utilization and other controls.ResultsSubjective expectations closely reflect patterns of observed utilization, are predicted by the same covariates as observed utilization, and correlate with objective measures of risk. Subjective expectations also add predictive power to models estimating insurance take-up, even after conditioning on prior health care use and other risk factors.ConclusionThe findings are indicative that on average people form quite accurate expectations, and support collecting subjective expectations about health services in household surveys for use in applied research

Effective Celebrity Endorsers: What Are the Rhetorical Factors?

Celebrity endorsements are a common technique used in advertising. While many have studied this marketing tool and its effectiveness, a gap remains in the research regarding overall effectiveness in celebrity choice and advertisement composition in terms of rhetoric. Oftentimes, there is an assumption that celebrity endorsers hold the most power in creating purchase intentions, yet concepts related to rhetoric suggest that other elements play an active role in this as well. Consequently, this study adds to the conversation of celebrity endorsements by examining five beauty advertisements that utilize celebrity endorsements to better understand their overall visual rhetoric and, thus, how they persuade consumers. Links are made to persuasiveness in terms of identity, credibility, design, and branding. The findings suggest that effectiveness cannot just be associated with a single element; rather, it is a conglomeration of rhetorical appeals ”visual rhetoric, credibility/trust, and coherence. Implications are also discussed in terms of how pinpointing the agent in an advertisement can provide specialists in the field with the necessary tools to more effectively persuade consumers and better market their products

The synthesis of biodegradable polymers using aluminium alkoxide initiators

Alkyl aluminium alkoxides have been used as initiators for the ring opening polymerisation of ε-caprolactone and δ-valerolactone. The effect of the reaction solvent on the kinetics of the polymerisation of ε-caprolactone has been studied. The rate of polymerisation was found to be faster in solvents of lower polarity and donor nature such as toluene. In general solvents of higher polarity resulted in a decreased rate of polymerisation. However solvents such as THF or DMF with a lone pair of electrons capable of forming a complex with the aluminium centre slowed the polymerisation further. The size of the monomer also proved to be an important factor in the kinetics of the reaction. The six membered ring, δ-valerolactone has less ring strain than the seven membered ring ε-caprolactone and thus the polymerisation of δ-valerolactone is slower than the corresponding polymerisation of ε-caprolactone. Both the alkoxide and alkyl group structures have an effect on the polymerisation. In general bulkier alkoxide groups provide greater steric hindrance around the active site at the beginning of the reaction. This causes an induction or a build up period that is related to the both the steric hindrance and also the electronic effects provided by the alkoxide group. The alkyl group structure has an effect throughout the polymerisation because it remains adjacent to the active centre. The number of alkoxide groups on the aluminium centre is also important, using a dialkoxide as an initiator yields polymers with molecular weights approximately half that of the corresponding reactions using a mono alkoxide. Transesterification reactions have also been found to occur after most of the monomer has been consumed. These transesterification reactions are exaggerated as temperature increases. A method of producing tri-block co-polymers has also been developed. A di-hydroxy functional pre-polymer, PHBV, was reacted with an aluminium alkyl to form a di-alkoxide macroinitiator which was subsequently used as an initiator for the polymerisation of ε-caprolactone to form an ABA type tri-block co-polymer. The molecular weight and other properties were predictable from the initial monomer/initiator ratios