Due to their extraordinary electronic properties, Quantum Dots (QDs) are potentially very useful nanoscale devices and research tools. As their electrons are confined in all three dimensions, the energy spectra of QDs is descrete, similar to atoms and molecules. Because the gaps between these energy levels is inversely related to the size of the QD, very small QDs are desirable. Carbon nanotubes have long been touted as fundamental units of nanotechnology, due to their structural, optical and electronic properties, many of which are a result of the confinement of electrons in the trans-axial plane of the nanotube. It is known that their band gap structure is altered under deformation of their cross section. It is proposed that one way to fabricate a very small quantum dot is by confining electrons in the nanotube so that they may not freely move along its length. A structure to produce this confinement has been described elsewhere, namely the carbon nanotube cross, consisting of two carbon nanotubes, with the the one draped over the other at ninety degrees. It is thought that this structure will induce local physical deformations in the nanotube, resulting in local changes in electronic structure of the top nanotube at the junction of the cross. These band gap shifts may cause metal-semiconductor transitions, resulting in tunnel barriers that axially the confine electrons in the nanotube. This thesis investigates the possibility that the carbon nanotube cross may exhibit QD behavior at the junction of the cross, due to these local band gap shifts. A device for carbon nanotube growth, using Chemical Vapor Deposition, has been designed, and may be built using microfabrication techniques. This device consists of electrodes (for electrical measurements of the nanotubes) and catalyst regions (to initiate nanotube growth), lithographically patterned in a configuration that promotes carbon nanotube formation. Unfortunately, due to fabrication issues, this effort is a work in progress, and these devices have not yet been constructed. However, an experimental methodolgy has been developed, which provides a framework for eventually building a carbon nanotube cross, and investigating the possibility of QD behavior at the junction of the cross. This structure has also been investigated computationally. Molecular dynamics simulations were used to obtain equilibrium geometries of the carbon nanotube cross, and it was found that their are many different meta stable states, corresponding to different types of nanotube, and different physical arrangements of these nanotubes. The electronic structure of the carbon nanotube cross was calculated using the density functional theory. Band gap energies similar to experimental values were obtained. A one-to-one spatial correlation between deformation and band gap and conduction band shifts were observed in the top carbon nanotube of the nanotube cross. Small tunnel barriers, inferred from both the calculated band gap and LUMO energies, are observed, and could well be sufficient to confine electrons along the axis of the nanotube. The results described in this thesis, while not definitive, certainly indicate that a QD probably would form at the junction of a carbon nanotube cross, and that further investigation, both experimental and computational, is warranted.

The process of vapor extraction (VAPEX) is a recovery process which targets the heavy oil and bitumen resources. Owing to high viscosity values for these unconventional types of oil, the recovery processes in such reserves are still challenging. The unconventional oil recovery processes usually include a mechanism for reducing the oil viscosity by means of heat, solvent, or both. The process of VAPEX utilizes the injection of a light hydrocarbon solvent into a reservoir for recovering the viscous oil in place by diffusing into the oil and by providing sufficient mobility to the oil upon dilution. Although this process offers a variety of advantages over the alternative thermal recovery processes such as SAGD or CSS, it suffers from two major drawbacks. First, the oil production rates obtained in the VAPEX process are considerably lower than those obtained in the thermal processes. Second, the solvent cost is considerably high. We tried to tackle these two problems during this research and we searched for potentials for an improved VAPEX process. Three potentially improved occurrences of a VAPEX project were found when: 1) the injected solvent was superheated, 2) the wettability of media was altered to oil-wet, and 3) the vugs were distributed in the porous media. Warm VAPEX process is introduced in which the VAPEX process is thermally augmented through superheating the solvent vapor. An attractive feature of this process is the capability of the solvent in being able to condense at the bitumen-solvent interface, which provides the opportunity for the bitumen to be upgraded in-situ through asphaltene precipitation. The asphaltene precipitation was not observed during the conventional vapor extraction process and was only observed during the warm VAPEX process. Upon a moderate level of superheating, the production rate of bitumen was sufficiently improved while the solvent content of the produced oil was significantly decreased as a result of decreased solubility of solvent in the oil at elevated temperatures. Therefore, more oil was produced at lower costs. The warm VAPEX experiments were conducted at 4 temperature levels in high and low permeability media using Cold Lake bitumen and Lloydminster heavy oil blend, n-pentane was used as solvent. The warm VAPEX process was found to be more effective for Cold Lake bitumen and for less permeable media. The potential of in-situ upgrading decreased when the level of superheating increased. The second potential for an improved VAPEX process obtained when the wettability of porous medium was altered to oil-wet conditions. Although this wettability condition is harmful to steam-based recovery processes, such as SAGD, it becomes beneficial to VAPEX. For the application of VAPEX process in fractionally wet media the wettability of glass beads was altered to oil-wet conditions through silylation process, and the VAPEX experiments were conducted in a random packing of water-wet and oil-wet beads of similar size at 7 different compositions. A substantial increase in the oil production rate was observed in a completely oil-wet medium, compared to the water-wet medium. By increasing the fraction of oil-wet beads in the packing up to a critical composition, the production rate of live oil increased linearly with the increase in the fraction of oil-wet beads in the packing during the vapor extraction process. Beyond this critical composition, however, the production rate of live oil did not change significantly with further increase in the fraction of the oil-wet beads in the randomly packed medium. Vugs were also found to be beneficial to the production performance of the VAPEX process. The presence of vugs was investigated in synthesized vugular media at 4 different levels of vuggy-to-total pore volume ratios. The performance of vugular media was compared to that of the homogeneous sintered media. The vugs facilitated the production of oil during the VAPEX process by providing flow communication between the vugs and the surrounding matrix, and therefore, by providing a local high permeability pathways towards the production well. A peak in the oil production rate was observed whenever a series of vugs were simultaneously invaded by the solvent vapor. The overall production rate of oil was higher in vuggy media compared to a homogeneous media at the same overall porosity and permeability. Furthermore, the magnitude of residual oil saturation left behind was also slightly lower in vuggy medium because the vugs were perfectly drained. Finally, a constant rate air injection (CRAI) porosimetry method was developed for characterization of vugs in a vugular media. This method was successfully tested in different synthetic vugular media, and the results illustrated higher accuracy in CRAI porosimetry method compared to constant rate mercury porosimetry. CRAI porosimetry method was also employed for identification of higher permeability regions embedded in a matrix of lower permeability. The analysis of a typical porosimetry signal was also modified.

The performance of astronomical interferometer arrays operating at (sub) millimeter wave-lengths is seriously compromised by rapid variations of atmospheric water vapour content that distort the phase coherence of incoming celestial signals. Unless corrected, these phase distortions, which vary rapidly with time and from antenna to antenna, seriously compromise the sensitivity and image quality of these arrays. Building on the success of a prototype infrared radiometer for millimeter astronomy (IRMA I), which was ued to measure atmospheric water vapour column abundance, this thesis presents results from a second generation radiometer (IRMA II) operating at the James Clerk Maxwell Telescope (JCMT) on Mauna Kea, Hawaii from December, 2000 to March, 2001. These results include comparisons with other measures of water vapour abundance available on the summit of Mauna Kea and a comparison with a theorteical curve-of-growth calculated from a new radiative transfer model, ULTRAM, developed specifically for the purpose. Plans for a third generation radiometer (IRMA III) are also be discussed. / xii, 143 leaves : ill. ; 28 cm.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

Biodegradable edible films are both economically and environmentally important to the food industry as packaging and coating materials, as the industry seeks to find a replacement to traditional petroleum-derived synthetic polymers. The overall goal of this thesis was to design a canola protein isolate (CPI)-based biodegradable and edible film that provides excellent mechanical, optical and water vapor barrier properties. A better understanding of the potential of CPI for use as a film-forming ingredient could lead to enhanced utilization and value of the protein for food and non-food applications. In study one, the mechanical, optical and water vapor barrier properties of CPI-based films were investigated as a function of protein (5.0% and 7.5% w/w) and glycerol (30%, 35%, 40%, 45%, and 50% w/w of CPI) concentrations. Overall, as the glycerol concentration increased for the 5.0% and 7.5% CPI-based films, mechanical strength and flexibility decreased and increased, respectively. Film strength was also found to increase at the higher protein concentration; however corresponding changes to film flexibility differed depending on the testing method used. For instance, puncture deformation testing indicated that film flexibility was reduced as the CPI concentration was raised, whereas tensile elongation testing indicated no change in extensibility between the two CPI concentrations. Film transparency was found to increase with increasing levels of glycerol and decreasing levels of CPI, whereas water vapor permeability was found to increase with increasing levels of both glycerol and protein. In study two, mechanical, optical and vapor barrier properties of CPI-based films were evaluated as a function of plasticizer-type (50% (w/w of CPI), glycerol, sorbitol, polyethylene glycol 400 (PEG-400)) and fixative condition (0% and 1% (w/w of CPI), genipin). CPI films prepared with sorbitol were significantly stronger than films with PEG-400, followed by films with glycerol, whereas the flexibility of CPI-based films with glycerol was higher than films with PEG-400, followed by films with sorbitol. In all cases, films prepared with genipin were stronger and less malleable than un-cross linked films. CPI films with glycerol were more transparent than films with sorbitol, followed by films with PEG-400, and the addition of genipin significantly increased the opacity of CPI films. CPI films prepared with glycerol also showed poorer water vapor barrier property than films with PEG-400, followed by films with sorbitol, however, no differences were observed in the presence and absence of genipin. In summary, as the plasticizer concentration increased or protein concentration decreased, CPI films became weaker, more flexible and clearer; however their water vapor barrier properties became poorer as both plasticizer and protein concentration increased. Moreover, CPI films with sorbitol and genipin were found to be stronger, less malleable and permeable to moisture than CPI films with or without genipin, and in the presence of glycerol or PEG-400. Overall, CPI could be considered as a potential material for the development of biodegradable edible packaging in the future.