1,895 research outputs found

    A Study of Functionalized Aromatic Compounds and Their Applications.

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    The present work has been conveniently divided into two separate sections, and it is necessary to explain the need for this unusual course of action. As outlined in the Acknowledgement section, this research work was funded by two separate bodies, the U.S. Navy and the Ministry of Defence. The first year's work was initally intended to be solely a single year's research post and the U.S. Navy funding provided was only ever intended to be sufficient for that time. However, after several months into the research programme, the opportunity to pursue a Ph.D. was facilitated by the attainment of a generous S.E.R.C./M.o.D. grant. The materials synthesized and characterized in the two volumes are closely related and find use in similar fields of application. In particular the allyl-functionalized derivative of Bisphenol-A, 2,2'-bis(3-allyl-4-hydroxyphenyl)isopropylidene figures particularly strongly in both areas of the research as both a parent compound for a number of Surface acoustic wave (SAW) vapour sensor coatings, and also as the parent compound for several potential matrix resins in the second section of the research. The two funding bodies are quite discrete from one another and during the course of the preparation of this thesis large portions of manuscript were edited by supervisors/consultants from both establishments. In the interests of discretion it was decided at a very early stage to divide the thesis into two, thus enabling each volume to be safely submitted for discussion without fear of causing any offence to either funding body

    Vitamin D levels of anaesthetists in the department of anaesthesiology at the University of the Witwatersrand

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    A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Medicine in the branch of AnaesthesiologyBackground and Objective There has been a recent resurgence of interest in vitamin D and its far-reaching effects in physiology and pathophysiology. Theatre personnel, and all indoor workers, should be cognisant of vitamin D deficiency as a real occupational hazard. Vitamin D deficiency is a global problem that has been studied extensively in colder climates and even been found in warmer climates. No research was identified among medical personnel in South Africa. The primary objective of this study was to describe serum 25-hydroxyvitamin D (25(OH)D) levels of anaesthetists. The secondary objective was to describe and compare factors influencing vitamin D levels in anaesthetists who are vitamin D insufficient to those who are not. These factors included: ethnicity, gender, body mass index (BMI), multivitamin use, calcium or vitamin D supplementation, sun exposure, vitamin D intake from diet alone, vitamin D intake from diet and supplementation and calcium intake (dairy). Methods Data was collected over a period of one month, in winter (mid-July to mid-August 2013). On the morning of sample collection anaesthetists agreeing to participate signed the informed consent (Appendix 2), prior to enrolment in the study. The anaesthetists then completed the questionnaire (Appendix 5). The following data was obtained from the questionnaire: age, gender, ethnic group, dietary supplementation, sun exposure, sunscreen use, BMI and diet. Each participant had 5 ml of blood collected in a standardised manner into a purple top ethylenediaminetetraacetic acid blood specimen tube. The processing of samples was done by qualified laboratory personnel using standard chemical pathology equipment and procedures. High Performance Liquid Chromatography was performed to determine 25(OH)D levels using a Shimadzu® Nexera X2 Ultra performance liquid chromatography system with a photodiode array detector (Shimadzu®, Japan). Results The median 25(OH)D was 43.8 nmol/l (IQR 26-76), with 51 of 89 (57.30 %) anaesthetists being vitamin D insufficient. There was a statistically significant association between ethnicity and vitamin D status (p<0.001). Twenty-one (80.77 %) Indian anaesthetists and 14 (70.00 %) black anaesthetists were vitamin D insufficient, as compared to only 10 (28.57%) white anaesthetists. There was no significant association between the other secondary objectives-gender (p=0.60), sun exposure (p = 0.93), vitamin D intake from diet alone (p= 0.07), vitamin D intake from diet and supplementation (p=0.05) and calcium intake (p=0.55) and vitamin D status. There was no significant difference between BMI and vitamin D status. When a comparison was made between the two groups of BMI <25 and BMI ≥25, using a Mann-Whitney test the two-tailed P value was 0.6791. There was a significant association between multivitamin use (p=0.01) and vitamin D status. Conclusion Vitamin D should no longer be a forgotten vitamin. The insufficient vitamin D levels of anaesthetist in this study, puts them at risk for pathology far beyond bone health. Adequate vitamin D levels should be seen as essential, rather than optional, even in “sunny” climates.MT201

    Positioning and aligning CNTs by external magnetic field to assist localised epoxy cure

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    Abstract This work focuses on the generation of conductive networks through the localised alignment of nano fillers, such as multi-walled carbon nanotubes (MWCNTs). The feasibility of alignment and positioning of functionalised MWCNTs by external DC magnetic fields was investigated. The aim of this manipulation is to enhance resin curing through AC induction heating due to hysteresis losses from the nanotubes. Experimental analyses focused on in-depth assessment of the nanotube functionalisation, processing and characterisation of magnetic, rheological and cure kinetics properties of the MWCNT solution. The study has shown that an external magnetic field has great potential for positioning and alignment of CNTs. The study demonstrated potential for creating well-ordered architectures with an unprecedented level of control of network geometry. Magnetic characterisation indicated cobalt-plated nanotubes to be the most suitable candidate for magnetic alignment due to their high magnetic sensitivity. Epoxy/metal-plated CNT nanocomposite systems were validated by thermal analysis as induction heating mediums. The curing process could therefore be optimised by the use of dielectric resins. This study offers a first step towards the proof of concept of this technique as a novel repair technology.</jats:p

    What are we going to do about a problem like polymer chemistry? Develop new methods of delivery to improve understanding of a demanding interdisciplinary topic

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    Following collaboration between two chemistry lecturers and an academic developer an attempt was made to enhance the learning of students within a chemistry module through the adaptation of the delivery of content material. This paper reports a piece of practitioner led research which considered how effective the approach developed was upon the level of student understanding and the process through which this occurred. The module delivery was altered from an emphasis on the transmission of knowledge through a traditional lecture format, to rotating small group problem based sessions and the use of concept maps. Student feedback and higher grades achieved appear to demonstrate it was effective

    Developing (Quantitative Structure Property Relationships) QSPR Techniques to Predict the Char Formation of Polybenzoxazines

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    This study uses the Molecular Operating Environment software (MOE) to generate models to calculate the char yield of polybenzoxazines (PBz). A series of benzoxazine (Bz) monomers were constructed to which a variety of parameters relating to the structure (e.g., water accessible surface, negative van der Waals surface area and hydrophobic volume, etc.) were obtained and a quantitative structure property relationships (QSPR) model was generated. The model was used to generate data for new Bz monomers with desired properties and a comparison was made of predictions based on the QSPR model with the experimental data. This study shows the quality of predictive models and confirms how useful computational screening is prior to synthesis

    Predicting Glass Transition Temperatures of Polyarylethersulphones Using QSPR Methods

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    The technique of Quantitative Structure Property Relationships has been applied to the glass transition temperatures of polyarylethersulphones. A general equation is reported that calculates the glass transition temperatures with acceptable accuracy (correlation coefficients of between 90–67%, indicating an error of 10–30% with regard to experimentally determined values) for a series of 42 reported polyarylethersulphones. This method is quite simple in assumption and relies on a relatively small number of parameters associated with the structural unit of the polymer: the number of rotatable bonds, the dipole moment, the heat of formation, the HOMO eigenvalue, the molar mass and molar volume. For smaller subsets of the main group (based on families of derivatives containing different substituents) the model can be simplified further to an equation that uses the volume of the substituents as the principal variable

    An Incident Control Centre in action: Response to the Rena oil spill in New Zealand

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    Following the Rena grounding and oil spill in the Bay of Plenty, New Zealand, an Incident Command Centre was established which, among other tasks, coordinated a volunteer clean-up effort. We interviewed volunteers and organisers to gain insight into the efficacy of the volunteer coordination effort. Volunteers praised the system of communication and the involvement of indigenous groups. They expressed a desire for better training, more flexibility and community autonomy, a quicker uptake of volunteer support, and the use of social media. Locating the Incident Command Centre in a single site aided interaction between experts, and the sharing of resources. Overall, the volunteer coordination was considered a success
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