The Aqueous Dispersion of Carbon Nanotubes

This work has focused on the use of biological molecules such as amino acids, glycolic acids, ribonucleosides and simple sugars to improve MWCNT aqueous dispersibility through both covalent and non-covalent functionalisation. Oxidative treatment of MWCNTs with 6 M nitric acid has been shown to be a mild, yet effective method for introducing carboxylic acid groups, which are known to improve their dispersion, to the surface. The subsequent ionic interactions of these carboxylic acid groups with selected acidic, basic and neutral amino acids was investigated with a view to this further increasing the aqueous dispersibility of the MWCNTs. Of the amino acids considered basic arginine was found to provide the greatest improvement with the MWCNT concentration increasing from 0.35 to 6.79 mg/mL. The carboxylic acid groups of the oxidised MWCNTs were also used to covalently attach the amino acids through formation of an amide bond. In this instance taurine was found to be the most effective amino acid with dispersibility more than doubling. Non-covalent functionalisation of the MWCNTs was also achieved with taurine functionalised poly(acrylic acid), which resulted in a vefold increase in the concentration of MWCNTs dispersed when compared with poly(acrylic acid). Diazonium chemistry is widely used for the functionalisation of CNTs with aryl groups and in this work a diazonium reaction was used to covalently functionalise MWCNTs with pyridine. These pyridine groups were then used as the basis for the covalent attachment of the sugars ribose, fructose and sucrose. Functionalisation with pyridine alone did not improve the aqueous dispersion of the MWCNTs, however the subsequent attachment of the sugars led to enhanced MWCNT dispersibility with sucrose the most effective at 20 ug/mL. The effect of functionalisation on MWCNT dispersibility was probed using UV-vis- NIR spectroscopy. The modied MWCNTs were further characterised using TGA, TEM, Raman and FTIR spectroscopy

Morphine-induced modification of quinine palatability: Effects of multiple morphine-quinine trials

Contemporary research investigating the effects of opiate receptor agonists and antagonists indicates a role for endorphinergic mechanisms in the control of consummatory behaviours. One way in which opiates may exert an effect on feeding is by altering the hedonic properties or palatability of food and drink. Investigations of the role of palatability in the effect of opiates on feeding and drinking have primarily considered the effect of single exposures to opiates. Recognizing that chronic exposure to opiates may result in the development of tolerance to their palatability-altering properties, the taste reactivity test, a direct measure of the hedonic properties of a tastant, was used to assess the ability of morphine to modify the palatability of a bitter quinine solution across eight conditioning trials (Experiment 1). Morphine consistently reduced aversive reactions to the quinine solution across all eight conditioning trials, but tolerance did not develop to this effect. In tests for conditioned modification of quinine palatability, administered after the third and the eighth conditioning trial, quinine elicited conditioned attenuation of aversive reactions in the Contingent, but not in the Noncontingent group. Hence, there was evidence of drug-similar conditioned responses suggesting that an association had been established between the effect of morphine on palatability, and the taste of quinine. In order to determine how rapidly this association was established, a second experiment was conducted whereby subjects received a single injection of morphine 30 min prior to a 10 min infusion of quinine. The results of this experiment indicated that a single exposure is insufficient for the formation of an association between the effect of morphine on palatability, and the taste of quinine. In summary, therefore, tolerance did not develop to the ability of morphine to attenuate aversive reactions to the taste of quinine. Furthermore, quinine elicited conditioned attenuation of aversive reactions when assessed during drug-free tests, suggesting that the palatability of quinine was conditionally altered in a positive direction following its association with morphine

Sharon Clarke, piano

Clarke, Sharon, pian

Extreme summer heat in Phoenix, Arizona (USA) under global climate change (2041-2070)

Summer extreme heat events in the arid Phoenix, Arizona (USA) metropolitan region for the period 2041-2070 are projected based on the ensemble of ten climate models from the North American Regional Climate Change Assessment Program for the SRES A2 greenhouse gas emissions scenario by the Intergovernmental Panel on Climate Change. Extreme heat events are identified by measures related to two thresholds of the maximum daily air temperature distribution for the historical reference period 1971-2000. Comparing this reference period to the model ensemble-mean, the frequency of extreme heat events is projected to increase by a factor of six to 1.9 events per summer and the average number of event days per year is projected to increase by a factor of 14. The inter-model range for the average number of EHE days per summer is larger for the projected climate, 10.6 to 42.2 days, than for simulations of the past climate simulations (1.5 to 2.4 days)

Extreme summer heat in Phoenix, Arizona (USA) under global climate change (2041-2070)

Summer extreme heat events in the arid Phoenix, Arizona (USA) metropolitan region for the period 2041-2070 are projected based on the ensemble of ten climate models from the North American Regional Climate Change Assessment Program for the SRES A2 greenhouse gas emissions scenario by the Intergovernmental Panel on Climate Change. Extreme heat events are identified by measures related to two thresholds of the maximum daily air temperature distribution for the historical reference period 1971-2000. Comparing this reference period to the model ensemble-mean, the frequency of extreme heat events is projected to increase by a factor of six to 1.9 events per summer and the average number of event days per year is projected to increase by a factor of 14. The inter-model range for the average number of EHE days per summer is larger for the projected climate, 10.6 to 42.2 days, than for simulations of the past climate simulations (1.5 to 2.4 days).Projektionen für extreme Hitzeereignisse in den Sommermonaten in Phoenix, Arizona (USA) wurden für den Zeitraum 2041-2070 unter der Annahme des SRES A2 Treibhausgasemissionsszenarios des Intergovernmental Panel on Climate Change erstellt. Dafür wurden Simulationsergebnisse eines Ensembles von zehn Klimamodellen ausgewertet, die im Rahmen des North American Regional Climate Change Assessment Programmes angewendet wurden. Die extremen Hitzeereignisse wurden mit Hilfe von Kriterien bestimmt, die auf Schwellenwerttemperaturen für die maximalen täglichen Lufttemperaturen für die Referenzperiode 1971-2000 beruhen. In der Zukunft versechsfacht sich im Ensemblemittel die Häufigkeit der Extremereignisse (~ 1.9 Ereignisse pro Sommer) im Vergleich zum Referenzzeitraum mit einer vierzehnfachen mittleren Anzahl der Hitzetage pro Sommer. Dabei vergrößert sich die Schwankungsbreite der Modelle bezüglich der mittleren Anzahl der Hitzetage pro Sommer in der Zukunft gegenüber der der Vergangenheit von 1.5-2.4 auf 10.6-42.2

Execution Batch Monitor for Processing Student Jobs

This study deals with the investigation and implementation of a method of reducing operating system overhead for the short-running student jobs at Oklahoma State University. The method chosen is that of an execution batch monitor which eliminates much of the job overhead in processing these student jobs. Sound operating system principles and techniques are studied and incorporated into the monitor, as it assumes some of the operating system functions for the jobs which it processes.Computing and Information Science

Making connections in the Company of Pigeons

Sharon and Helen introduce us to the world of pigeon geography and offer playful ways to explore the world

A reconstruction of changes in land use/land cover in Vermont relative to sensitivity of surface waters to acidic deposition

Patterns of land use/land cover explain some of the spatial variability in sensitivity of surface waters to acidic deposition. Historic changes in land use/land cover may further explain some of the spatial variability. A map of land use/land cover changes needs to be compiled before this relationship can be analyzed. The objectives of this research are: 1) to determine the feasibility of mapping historic land use/land cover changes using Vermont as a pilot study, 2) to map the historic land use/land cover changes for Vermont, and 3) to evaluate and describe the resultant map. Relevant literature on land use/land cover is reviewed for maps and other descriptive information. The first step in compiling the map is to determine the classes of change which would influence the sensitivity of surface waters to acidic deposition. The map is constructed using present land use/land cover maps, topographic maps, and a 1935 map on quality of land for farming. These maps are augmented by descriptions of land use/land cover changes, information on successional stages, and relationships between land uses and physiography. The mapped categories are: nonforested lands, forested lands with agricultural potential, permanently coniferous forest, permanently deciduous forest, permanently mixed forest, permanently forested wetland, ski areas, and water. The composition and spatial location of each of these categories is discussed. In addition, an assessment of the reliability of the map is made using estimates of the percentage of each county in each of the major land uses or land covers