title: Synthesis and NMR Studies of Chiral Transition Metal Clusters

contributor:
McGlinchey, M. J.
Chemistry

subject: synthesis, chiral, transition, metal, clusters, spectroscopy, ligands

abstract:
 A series of chiral transition metal clusters of the type MCo2(CO)6C-CO2R, where M = Co(CO)3, (C5H5)Mo(CO)2, (i-Pr-C5H4)Mo(CO)2 or (indenyl)Mo(CO)2 and R =menthyl or exo-bornyl have been synthesized and characterized using FAB mass spectrometry and high field NMR techniques. The isopropyl Cp and the indenyl ligands served as NMR probes to detect the chirality created by the incorporation of the terpenoidal capping group.

 The tricobalt clusters were treated with the bidentate ligands arphos, Ph2AsCH2CH2PPh2 and diphos, Ph2PCH2CH2PPh2. Treatment with arphos yields a pair of diastereomers which are interconverted via the migration of the Ph2As terminus of the arphos ligand from one cobalt vertex to another. This fluxionality was monitored by variable-temperature 31P NMR spectroscopy. The diphos cluster is not a fluxional molecule. However, the Co(CO)2P vertices are diastereotopic and give two signals in the 31P NMR. Thus, diphos serves as a convenient probe for chirality.

 In the case where M = Co(CO)3 , the two remaining cobalt vertices are diatereotopic and are, in principle, not equally susceptible to attack by an incoming ligand. To test for chiral discrimination, these molecules have been treated with several different phosphines. If the reaction were to proceed with any degree of selectivity, the 31P NMR spectrum ought to show resonances of unequal intensity. Such results have been obtained when a bulky phosphine, such as tricyclohexylphosphine, has been employed.

abstract: Thesis

abstract: Master of Science (MSc)


title: A CBI Module and User Guide for Teaching Organic Chemistry

contributor:
Crux, S.
McCarry, B.
Chemistry

subject: module, teaching, organic, chemistry, students, CBI, technology, curriculum

abstract:
 This project presents the development of a lesson design format on "Introduction to Organic Chemistry" for CBI - computer-based instruction. The design is to be used with the authoring program, Private School, an intelligent delivery system database.

 The community college system has experienced many changes over the past few years. The changing political, economic and social climate has forced the community college system to re-examine how courses are delivered. Along with this, employers are demanding computer-literate students. There is a need for teachers to look at alternative delivery methods such as CBI. The addition of Computer-based learning to the chemistry curriculum at the community college is designed to do just that. CBI enhances student learning by providing an alternative delivery methodology for studying chemistry concepts, which can be abstract and difficult to comprehend.

 Computer-based learning has been slow to be implemented at community colleges. This lesson, designed for the computer courseware database, Private School, offers community college teachers a framework to use for their own curriculum
initiatives, thus allaying some of the fears and anxieties associated with computer
technology.

 Throughout the development of the computer-based instructional package, teacher involvement is critical. The success of such a teaching medium depends upon the commitment of the teacher/designer. The monitoring of student learning and of student progress must be built into the design.

 The instructional development model of Kemp, Morrison and Ross was used as the foundation for making decisions about instructional objectives, content, learning activities, resources, learner characteristics and student evaluation. The curriculum was then used as an example for the User Guide to help teachers with the development of their own CBI. This project describes 5 phases for the implementation of CBI into community colleges: teacher familiarization, instructional design, data entry, student familiarization and student evaluation and progress.

 CBI can provide resources for learning which are effective, richer, available for longer hours, and open to a wider range of college students. CBI also provides students with greater control over timing and pace, and there is more likelihood of resources suiting their style and stage of each student's learning.

abstract: Thesis

abstract: Master of Science (Teaching)


title: Electronic Correlation in C60 and Other Molecules

contributor:
Kallin, C.
Berlinsky, A. J.
Physics and Astronomy

subject: electronic, correlation, molecules, superconductivity, energy, pair-binding, Hubbard

abstract:
 In this thesis, we investigate the possibility that a purely electronic mechanism is the cause of superconductivity in C60 materials. Several computational methods are adopted to calculate the pair-binding energy. They are perturbation theory, exact diagonalization, Gutzwiller projection, and auxiliary field Monte Carlo. Results from these different methods are compared with each other both in a C60 molecule and in other smaller molecules in order to test conclusions about whether or not a purely electronic mechanism can lead to an attractive interactions between electrons in C60 molecules.

 Besides this test of the superconductivity mechanism, we also explain in detail how to apply these different computational methods to C60 for the specific geometry of C60. Clearly illustrating these computational methods is the second goal of this thesis.

 Our final conclusion is that for both small and large Hubbard interaction U, there is pair binding in a single C60 molecule. For intermediate Hubbard interaction strength, there is no clear evidence for pair binding for the range of temperatures we explored. We suggest that the truncation of the Coulomb interaction, which is implicit in the Hubbard Hamiltonian, may suppress pair-binding of electrons in C60 and that it may be necessary to consider a model that includes the long range character of Coulomb interaction. This is a subject for further study.

abstract: Thesis

abstract: Master of Science (MSc)


title: Some Thermodynamic Properties of Rare Earth Thiofluoride and Caβ"-Alumina Compounds

contributor:
Kay, D. A. R.
Materials Science and Engineering

subject: thermodynamic, properties, rare, earth, thiofluoride, compounds, galvanic, cells, electrolytes,

abstract:
Abstract Specifics included in thesis.
Thesis
Master of Engineering (MEngr)


title: The Synthesis of O-Alkylhydroxylamines and the Potentiation of Histamine in Canine Colonic Tissue

contributor:
Bell, Russell A.
Rangachari, P. K.
Chemistry

subject: synthesis, potentiation, histamine, canine, colonic, tissue, compounds, enzyme

abstract:
 Treatment of canine colonic tissue with some O-alkyl and O-benzyl hydroxylamines potentiated the response of the tissue to histamine in different experimental environments.

 Sixteen O-substituted hydroxylamine compounds were synthesized using a modification of the Gabriel synthesis. These compounds were tested for their ability to potentiate histamine in canine colonic tissue through diamine oxidase inhibition.

 Three procedures were used to determine their activity: (1) secondary rise -hydroxylamine derivatives were added to epithelial tissue preparations in Ussing chambers after an initial dose of histamine. Active compounds caused a secondary increase in the short circuit current across the tissue, (2) dose-response profiles were constructed for several hydroxylamine compounds to determine whether they caused a significant shift to the left of the normal histamine curve (potentiated response), and (3) diamine oxidase enzyme assays were performed to examine the ability of the hydroxylamine derivatives to inhibit partially purified diamine oxidase. This aided in determining if inactive compounds could not potentiate histamine due to an inability to access the enzyme in the epithelial preparation.

 The structure-activity relation observed indicates that: (1) active compounds are oxygen and not nitrogen substituted hydroxylamines, (2) branched compounds are less active than their straight chain analogues, (3) greater steric bulk of the alkyl substituent can decrease the activity of the compound, (4) the presence of a carbon-carbon double (allyl) or triple (4-pentynyl) bond does not affect the activity of the compound, (5) longer straight chain O-alkyl hydroxylamines are less active than shorter chain derivatives, (6) steric bulk of the benzyl compounds is not likely to be the cause of its inability to inhibit diamine oxidase since the cinnamyl derivative is active, and (7) meta- and para-oxygen substituents (-OH, -OCH3) on O-benzyl hydroxylamines increase their diamine oxidase inhibiting properties.

abstract: Thesis

abstract: Master of Science (MSc)


title: Synthesis, Characterization, and Kinetic Studies of Poly(Dimethylacrylamide) Macromonomer

contributor:
Zhu, Shiping
Chemical Engineering

subject: synthesis, characterization, kinetic, macromonomer, polymerization

abstract:
 The work in this thesis focuses on the search for a system that would allow for the
controlled anionic polymerization of N,N-dimethylacrylamide. The resulting polymer
would serve as a macromonomer equipped with a chain end functional group originated
from diallylamine.

 Poly(dimethylacrylamide) macromonomers were produced on a laboratory scale by reacting diallylamine with sec-butyllithium initiator, followed by the monomer addition. The synthesis was terminated, the polymer product precipitated in hexane, and dried in a vacuum oven at 45°C. The reactions were performed at 0°C and -77°C in tetrahydrofuran solvent.

 The polymerization control was achieved as a means of controlling the molecular weight and stereoregularity of the macromonomer, which in turn dictated solubility of the final product in the reaction solvent. The addition of triethylborane coordinating agent allowed for the polymerization of soluble product. The produced macromonomers characterized with atactic and syndiotactic structure were completely soluble in tetrahydrofuran.

 The molecular weights of macromonomers were evaluated by a gel permeation chromatography, GPC. The best results were obtained by using dimethylformamide as a mobile phase and poly(methylmethacrylate) standards

 The macromonomer yield was evaluated by 1H NMR and the stereoregularity by 13C NMR. Although the molecular weight of the macromonomer was under good control, the NMR measurements did not show the best yield control.

 The study of the triethylborane coordinating power showed that varying concentration of this ligand affected the solubility of the polymer in the reaction solvent. The soluble macromonomer was synthesized when triethylborane was in 1.5 molar excess over the initiator concentration. The 13C NMR measurements indicated that 23% of isotactic and atactic structure was required as a borderline for the solubility.

 The kinetic measurements performed in a batch reactor proved the livingness of the polymerization system with the propagation rate constant kobs equal to 1.9 · 10^-3 [1/s].

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: Interactions of Iron Dinitrosyl Compounds with Imidazole and its Derivatives

contributor:
Li, L.
Chemistry

subject: iron, dinitrosyl, compounds, derivatives, imidazole, biological, complex

abstract:
 Nitric oxide has been implicated in a number of biological processes, the majority of them involving iron nitrosyl complexes. The urgency then is to further study and characterize these complexes to further the understanding of biological mechanisms. However, the chemical sensitivity of these species precludes the purification and isolation of these compounds which, unfortunately, has directed the trend to merely detecting the presence of these compounds rather than isolating them. To this day, a large number of Electron Paramagnetic Resonance (EPR) detectable, biological compounds have not been isolated.

 To this end, the series of biologically relevant compounds of the form Fe(NO)2(L)2 [ L = imidazole 1, 1-methylimidazole (1-MeIm) 2, 4-methylimidazole (4-MeIm) 3, benzimidazole (benzim) 4, and 5,6-dimethylbenzimidazole (56benzim) 5 ] have been synthesized by direct reaction of the appropriate imidazole ligand with Fe(NO)2(CO)2. The compounds were extremely air sensitive, both in solution and as a dry solid. This hindered attempts to purify these compounds and so, infra red (IR), nuclear magnetic resonance (NMR) and EPR spectroscopic studies were undertaken of 2:1 reaction mixtures of the appropriate imidazole ligand and Fe(NO)2(CO)2. These studies revealed that the rapid substitution of the carbonyl ligands is facilitated by a catalytic, 17-electron, electron transfer chain mechanism (ETC), where the imidazole ligand acts to oxidize the 18-electron complex into the active 17-electron Fe(NO)2(CO)2+ species.

 In the course of the EPR study of 2, crystals formed that were suitable for single-crystal, X-ray diffraction. The compound crystallizes with a monoclinic unit cell, in the C2/c space group with unit cell dimensions: a= 13.985(5) Å, b = 11.529 (5) Å, c = 15.471(4) Å, α= 90°, β= 91.72(2)°, γ = 90°, V = 2493(2) Å^3, Z = 8. During the course of study of 6, crystals suitable for single crystal X-ray diffraction were obtained. The compound crystalizes with a monoclinic unit cell, in the P2/c space group and unit cell dimensions: a= 11.707(9) Å, b = 8.1783 (5) Å, c = 17.2489 (13) Å, α= 90°, β= 106.562 (1)°, γ = 90°, V = 1583.0 (2) Å^3 A, Z = 2.

 A relatively new mass spectrometry (MS) procedure was utilized for the reaction mixtures of 1 - 5, which involved a combination of electrochemical oxidation and electrospray. The method proved very useful, yielding data that could not be obtained by other MS techniques. Oligomeric species of the form L-[(Fe(NO)2L]x (x = 2,3,4,5 or 6), were also detected by MS for each compound reaction mixture. The oligomers involved linear chains of iron dinitrosyl fragments linked via the imidazole nitrogens. However, it is believed that these oligomers are produced as a result of the conditions met by the mass spectrometer.

 A reaction of Fe(NO)2(PPh3)(CO) with 1-MeIm was also performed in hopes of producing a more stable mono-substituted complex. However, the reaction also proceeded via an Electron Transfer Chain (ETC) pathway to produce Fe(NO)2(PPh3)2 6.

abstract: Thesis

abstract: Master of Science (MSc)


title: Phosphorus Mobility in Lacustrine Sediments Upon Lake Acidification

contributor:
Kramer, James R.
Geology

subject: phosphorus, mobility, lacustrine, sediments, lake, acidification

abstract:
 The forms of phosphorus in sediments of acid and non-acid shield lakes were determined in order to assess the effects of lake acidification on the mobility of sediment phosphorus. Sediment phosphorus is conveniently classified into three categories: non-apatite inorganic phosphorus (NAI-P), apatite-P and organic P. The distribution of P between different categories was found to be dependent on the lithology of the lake basin, the pH in the water column, and the redox conditions.

 More than 90% of inorganic P in shield lake sediments was in the NAI-P category, associated presumably with hydrated Fe and Al oxides. Organic P accounted for more than 40% of total P in sediments of acid lakes, which is proportionally higher than that found in sediments of neutral lakes. Bioavailable P, a measure of the fraction of sediment inorganic P readily available for biological utilization, amounted to ~70% of NAI-P, similar to that found in hard water lakes.

 A series of experiments was designed to investigate the immobilization of P from solution. The uptake of P by solid phase was explained by an adsorption mechanism. The quantitative estimates of phosphate sorption parameters for sediments of acid and non-acid lakes show that mineralogical and chemical characteristics of sediments are more important than the pH of water in determining their efficiency of P removal. Therefore, acidification of lakes does not significantly influence the uptake of P by sediments.

abstract: Thesis

abstract: Master of Science (MSc)


title: The Determination of Nitrogen-Containing Compounds in Heavy Syncrude Oils

contributor:
McCarry, B. E.
Quilliam, M. A.
Chemistry

subject: nitrogen, compounds, syncrude, oils, hydrocarbon, ionization, carbon, unsaturated

abstract:
 A two stage chromatographic separation method was adapted to the separation of nitrogen-containing compounds from heavy syncrude oils. Crude oil samples were first chromatographed on alumina to obtain an aliphatic fraction A1 (70 wt% of oil, <1% of total nitrogen), a polycyclic aromatic hydrocarbon fraction A2 (20%, 16%N) and a nitrogenous fraction A3 (3%, 80%N). The nitrogenous fraction was further separated on silicic acid into three fractions: a secondary-PANH fraction S1 (61% total N), an amino-PAH and tertiary-PANH fraction S2 (4%N) and a tertiary-PANH fraction S3 (9%N). One Tar Sand and two oil residue samples, provided by Shell Canada Ltd, were taken through this procedure.

 The nitrogen-containing fractions were analyzed by mass spectrometry (electron impact, methane chemical ionization and ammonia chemical ionization) and by two chromatographic methods (gas and reverse phase liquid chromatography). Further analyses were performed using gas chromatography/mass spectrometry, liquid chromatography/mass spectrometry and nuclear magnetic resonance (1H and 13C) spectroscopy.

 The nitrogenous components in the S1 fractions were shown to be alkylated carbazoles, containing from one to twenty carbons attached to the carbazole nucleus, in varying degrees of unsaturation ranging from zero to five degrees of unsaturation. The distribution of carbon substitution maximized in the C5 to C8 range for the different series of alkylcarbazoles. The distribution of the degrees of unsaturation in the Tar Sand oil sample was: saturated carbazoles, 32%, 1-degree unsaturates, 23%, 2-degree, 9%, 3-degree, 16%, 4-degree, 12% and 5-degree, 8%. In the processed Peace River residue, the ratio between the saturated, 1-, 2-, 3-, 4- and 5-degree unsaturated carbazoles was 28%:39%:18%:6%:6%:3%. From the 1H NMR spectrum the ratio of benzylic to aliphatic resonances was 1:1.25 which was interpreted to mean that the alkyl chains attached to the carbazole nucleus were short on average. A complete lack of vinyl proton absorption indicated that few alkene bonds if any were present; thus, the degrees of unsaturations must be accommodated by rings or benzo-annulations.

 Of all the analytical methods used, ammonia chemical ionization mass spectrometry (NH3 CIMS) was found to be a most useful and selective method and was used in probe MS, GC/MS and LC/MS experiments. Reverse phase liquid chromatography (RPLC) was more useful in this work than capillary column gas chromatography (CCGC). A combination of nuclear magnetic resonance (NMR) experiments (1H, 13C, 13C spectral editing, 1H-13C shift correlation and 13C T1 ) was found to be extremely useful for these samples because of the unique information these experiments provided.

abstract: Thesis

abstract: Master of Science (MSc)


title: The Synthesis and Mutagenicity of 1-Nitrosopyrene and 1-Nitroso-8-Nitropyrene

contributor:
McCarry, B. E.
Chemistry

subject: synthesis, mutagenicity, nitrosopyrene, nitroso, compounds

abstract:
 1-nitropyrene and 1,8-dinitropyrene are environmental pollutants and direct-acting mutagens in bacteria. Studies have shown that reduction of the nitro group is essential for the expression of the mutageneity of these compounds and the formation of covalent DNA adducts in Salmonella typhimurium. It has also been shown that the corresponding amino compounds are only slightly mutagenic. Since the reduction of nitro compounds  to amino compounds must proceed via the nitroso and hydroxylamino intermediates, it has been proposed that the hydroxylamines derived from 1-nitropyrene and 1,8-dinitropyrene are the ultimate mutagens.

 1-nitrosopyrene and 1-nitroso-8-nitropyrene were synthesized and reduced to their corresponding hydroxylamines with ascorbic acid. While 1-nitrosopyrene (50,226 rev/nmole) was 50X more potent than 1-nitropyrene (985 rev/nmole) in the Ames Test, 1-nitroso-8-nitropyrene (8,000 rev/nmole) was 10X less potent than 1,8-dinitropyrene
(85,830 rev/nmole). The hydroxylamines derived from these compounds proved to be very labile species and could not be characterized.

abstract: Thesis

abstract: Master of Science (MSc)


title: An NMR Study on Solvent-Polymer Interactions

contributor:
Bain, A. D.
Chemistry

subject: NMR, solvent, polymer, synthetic, temperature, interaction

abstract:
 Approximately 80 percent of all synthetic polymers used are cross-linked polymers, unfortunately the characterization of cross-linked polymers has not kept up with their use. This study tries to help in the characterization of cross-linked polymer systems. More specifically the interactions of cross-linked polymer systems with solvents will be probed. Nuclear Magnetic Resonance (NMR) spectrometric techniques will be used to characterize solvent-polymer interactions.

 The cross-linked polymer system studied was the polymer ethylene glycol dimethacrylate (EGDMA) with methylmethacrylate (MMA). A splitting of the solvent signals was observed in the NMR spectrum which can be used to understand these solvent-polymer interactions. Several NMR parameters and swelling of the polymers were measured in order to understand these interactions. The chemical shift differences between the solvent types and the peak linewidths were measured. As the polymer becomes more highly cross-linked the chemical shift differences and the linewidths increases. This compactness can be monitored by measuring the degree of swelling of the polymer. In addition the possibility of an isotope effect was explored by monitored by placing the polymer in solvent mixture of CHCl3/JCDCl3 and varying the temperature. No isotope dependence was found to exist for chloroform over the temperature range analyzed. The degree of splitting and the occurrence of splitting was found to be dependent on the solvent system. In general, solvent splitting is present for solvents that are able to cause the polymer to swell appreciably. For 4.8 weight percent EGDMA in EGDMA/MMA polymer a splitting is usually observed for a solvent that is able to swell the polymer to twice its dry size. The association between the solvents and the polymers can be best explained by breaking the interactions into a number of components.

 The explanation is based on the presence of three interactions. A weak chemical interaction exists between the solvent and the polymer to account for the field dependent linewidths. A second chemical interaction that results is a binding between the solvent and the polymer and causes the solvent splitting to occur. The third interaction is a result of the increased rigidity and compactness of the polymer as the weight percent EGDMA in EGDMA/MMA polymer increases. Alternatively as the polymer becomes more compact the chemical shift difference between the two types of solvents increases.

 Ultimately, it is shown that NMR is a useful aid in understanding solvent-polymer interactions.

abstract: Thesis

abstract: Master of Science (MSc)


title: Synthesis and Characterization of Graft Polyelectrolytes

contributor:
Zhu, Shiping
Pelton, Robert
Chemical Engineering

subject: synthesis, characterization, graft, polyelectrolytes, polymers, particles

abstract:
 Water soluble polymers are used as flocculants in wastewater treatment, mineral processing, and pulp and paper production. The work in this thesis focuses on the synthesis of graft polyelectrolytes and the efficiency of the copolymers in flocculation. It was proposed that it would be advantageous to have clusters of high charge that can adsorb strongly to the particle surface, and a long chain of nonionic polymer to bridge the particles together.

 Electrolyte copolymers were produced using a high molecular weight polyacrylamide as the backbone polymer and a redox agent, ceric ammonium nitrate, to form a radical site on the polymer. DADMAC monomer was polymerized from these radical sites producing grafts of cationic charge. The copolymers were produced at a range of polymerization conditions including PAM concentration, amount of nitric acid, amount of ceric ion and polymerization temperature. Grafting was successful and homopolymerization of DADMAC was found not to occur. The graft polymers were characterized using NMR, charge titration, viscosity measurements, and gel fraction measurements.

 The copolymers were tested for flocculating properties using a model TiO2 system. The graft copolymers produced performed better than the backbone polyacrylamide, low and high molecular weigh polyDADMAC, and a commercial random copolymer of acrylamide and DADMAC. It was found that both the amount of charge and gel is very important in flocculation performance. However, the testing of the copolymers as a conditioner for a municipal sludge did not show improvement in the drainage rate.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: THE ROLE OF CELL SURFACE GRP78 AND ANTI-GRP78 AUTOANTIBODIES IN THE DEVELOPMENT AND PROGRESSION OF ATHEROSCLEROTIC LESIONS

contributor:
Austin, Richard
Biochemistry and Biomedical Sciences

subject:
Atherosclerosis
Endothelial Cells
GRP78
ER Stress
UPR
Adhesion molecules

abstract: Damage to the endothelium is an important contributor to the initiation and progression of atherosclerosis. GRP78 is an endoplasmic reticulum (ER)-resident molecular chaperone in normal healthy endothelium that functions to assist in the correct folding of newly synthesized proteins and to prevent the aggregation of folding intermediates. In addition, GRP78 is present as a transmembrane protein on the surface of lesion-resident endothelial cells. Surface GRP78 is known to act as a surface signaling receptor in cancer cells and is activated by anti-GRP78 autoantibodies (GRP78a-Abs) isolated from the serum of cancer patients. However, the role of cell surface GRP78 on endothelial cells and the influence of GRP78a-Abs in atherosclerosis is unknown. The objectives of this study were to investigate the effects of GRP78a-Abs on lesion development, examine whether engagement of cell surface GRP78 by GRP78a-Abs modulates endothelial cell function, and determine whether GRP78a-Abs were associated with cardiovascular disease (CVD) in humans. This research showed that ApoE-/- mice with advanced atherosclerotic lesions have elevated serum levels of GRP78a-Abs and ApoE-/- mice immunized against recombinant GRP78 demonstrated a significant increase in GRP78a-Abs titers as well as accelerated lesion growth. Furthermore, this work demonstrated that activation of surface GRP78 on endothelial cells by GRP78a-Abs significantly increases gene expression of adhesion molecules ICAM-1 and VCAM-1 as well as leukocyte adhesion through the NFκB pathway. Additionally, middle-aged to elderly adults at risk for CVD showed a tendency toward elevated circulating GRP78a-Ab levels.  Our results suggest that signaling through cell surface GRP78 can activate intracellular pathways that contribute to endothelial cell activation and augment atherosclerotic lesion development. These findings demonstrate a novel role for GRP78a-Abs and surface GRP78 receptor activity in endothelial cell function and the early stages of lesion development, as well as establish an initial framework for future work involving circulating GRP78a-Abs and atherosclerotic disease in humans. Furthermore, this work indicates inhibiting the interaction of GRP78a-Abs with cell surface GRP78 could present a novel therapeutic strategy to modulate lesion growth, thereby reducing the risk for atherosclerosis and cardiovascular disease.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Form of Aluminum(III) in Dilute Aqueous Solution

subject: form, aluminum, dilute, aqueous, solution, ionic, concentration

abstract:
 Using a potentiometric method on 10^-4M and 10^-5M Al(NO3)3 solutions at constant ionic strength (0.1 M KNO3) and temperature (25°C), titration curves were defined and examined with respect to three variables (total aluminum concentration, pH range, and time) in order to assess the reversibility of the aqueous system.

 Increasing pH titration interval decreased reversibility while increasing time interval led to a slight increase in reversibility. Decreasing the total aluminum concentration also slightly improved reversibility. Overall, the reversibility of the system was observed to be poor.

 Computer models were compared to experimental titration data in order to derive the speciation schemes which best fit the data. Polynuclear hydrolysis schemes fit the data best for the concentration levels as follows: Al^3+, Al(OH)4^-, and Al6(OH)15^3+ for 10^-5M Alt. Al^3+, Al(OH)4^-, and Al8(OH)20^4+ and/or Al13(OH)32^7+ for 10^-4M Alt.

abstract: Thesis

abstract: Master of Science (MSc)


title: Towards Radiopharmaceutical Synthesis Using Fluorous Chemistry

contributor:
Valliant, John Fitzmaurice
Chemistry

subject: radiopharmaceutical, synthesis, fluorous, chemistry, therapeutic

abstract:
 Nuclear medicine requires the use of radio labelled pharmaceuticals in order to carry out imaging and therapeutic protocols.1 Unfortunately, traditional radiolabelling approaches used in radiopharmaceutical synthesis often generate multiple products, which require exhaustive HPLC purification prior to use.2 Chromatographic purification reduces radiochemical yields, increases exposure, and can, in certain cases, preclude the use of shorter-lived isotopes.

 In light of the limitations of current radio labelling methods, we endeavored to develop a versatile and efficient radiolabelling strategy that would avoid the need for HPLC purification. To this end, the compounds to be labelled were first bound to a highly fluorinated stannylated precursor, which, when reacted with a radiohalogen, generated the corresponding radiolabelled compound. Unlike other halodestannylation reactions, however, the radiolabelled compound could be isolated from the stannylated precursor by elution through a fluorous Sep-Pak.

 As a model system, tris(perfluorohexylethyl)tin-3-benzoic acid (1), was synthesised and labelled. Compound 1 was prepared through a novel reaction which involved treatment of bromotris[(2-perfluorohexyl)ethyl]tin with the organozinc reagent 3-(ethoxycarbonyl)phenylzinc. Reaction of compound 1 with [18F]F2, followed by fluorous Sep-Pak purification, generated the corresponding labelled 3-[18F]fluorobenzoic acid in 27 min, in 30% radiochemical yield, and having a specific activity of 1966 mCi/mol. Alternatively, reaction of compound 1 with Na125I provided the corresponding product, 3-[125I[iodobenzoic acid, in <1 hr, in 75% radiochemical yield, and greater than 99% radiochemical purity. Prior tests clearly showed that any excess or unreacted substrate was fully removed from the product using a fluorous Sep-Pak.

 In addition to the initial validation studies, new synthetic methods were developed as a means of preparing more complex "fluorous" substrates. A coupling methodology was developed which permitted synthesis of a fluorous "tagged" benzamide, through reaction of 1 in the presence of HBTU with N,N-dimethylethylenendiamine. Subsequent labelling using F2 and I2 has been shown to generate the corresponding labelled benzamides, which are important agents for imaging melanoma and dopamine receptors.3 Another relevant radiopharmaceutical precursor, tris[(2-perfluorohexyl)ethyl]tin-3-benzylamine (2), was synthesized though reaction of bromotris[(2-perfluorohexyl)ethyl]tin with 1-(3-bromobenzyl)-2,2,5,5-tetramethyl-1,2,5-azadisilolidine. Compound 2 was successfully coupled to the chemotactic peptide, GFLM(f), and the product subsequently labelled with iodine. Compound 2 was also used to prepare the corresponding benzylguanidine (3), an important precursor to m-iodobenzylguanidine, which is used for imaging and therapy of neural crest tumors.4 Initial labelling results show that reaction of 3 with NaI and an oxidant generates the corresponding labelled m-iodobenzylguanidine.

 Results suggest that the fluorous synthesis method will offer several advantages over traditional radiolabelling strategies. The radiolabelled products are generated in high yield, through rapid and facile reactions that avoid the need for HPLC purification.

abstract: Thesis

abstract: Master of Science (MSc)


title: Preparation and Characterization of Organically Modified Sol-Gel-Derived Materials: Spectroscopic and Biological Assay Studies for the Development of Optical Biosensors Using Sol-Gel Immobilized Proteins and Enzymes

contributor:
Brennan, John D.
Chemistry

subject: preparation, characterization, materials, spectroscopic, optical, biosensors, proteins, enzymes, function

abstract:
 The goal of this research project was the development of a protocol for preparation of optically clear organic/inorganic hybrid materials that was amenable to entrapment of lipophilic biomolecules. The protocol involved the acid-catalyzed hydrolysis of mixtures of tetraethylorthosilicate (TEOS) with organosilane precursors, including methyltriethoxysilane (MTES), dimethyldimethoxysilane (DMDMS) and propyltrimethoxysilane (PTMS) in the presence and absence of the polymer additives poly(ethylene glycol) or poly(vinyl alcohol).

 The effect of organosilane precursors and polymer additives on the optical clarity, hardness and hydration stability of the resulting materials was characterized. It was determined that there was a limit to the amount of organosilane that could be added before the materials exhibited unacceptable characteristics. These limits were 20.0% (v/v) for MTES, 10.0% (v/v) for PTMS, and 5.0% (v/v) for DMDMS. Addition of PEG to these materials at levels up to 10.0% (w/v) resulted in good material characteristics. However, addition of PVA produced opaque materials with poor material properties. The internal environment of the materials was also probed using the environmentally sensitive fluorescent probes 7-azaindole (7AI) and prodan. These studies showed that the method of hydrolysis of the silane precursors and the aging conditions had a dramatic effect on the resulting material.

 The hybrid materials were used to entrap human serum albumin (HSA) and lipase to determine the effect of organic content on the biological function of these biomolecules. Both biomolecules retained a portion of their native function when entrapped in sol-gel-derived materials, and it was found that both proteins showed enhanced function in the presence of MTES. In the case of lipase, it was also determined that addition of PEG 600 at 10.0% (w/v in the gelation buffer) provided a dramatic increase in activity compared to materials without this additive, likely owing to a direct effect of the PEG on the stability of the entrapped protein.

 Following studies using bulk glasses, a protocol was developed for the preparation of optically clear sol-gel-derived thin films that was amenable to entrapment of biomolecules. The optimal method involved dipcasting of co-hydrolyzed materials containing 1.0 to 3.0% PEG. By careful control of the viscosity of the casting solution and the rate of film deposition, it was possible to form very stable thin films with excellent physical characteristics. These films were used to entrap the pH-sensitive, ratiometric fluorescent probe dextran-SNARF-1, resulting in a prototype of a fluorimetric pH sensor. Co-entrapment of the probe and lipase into sol-gel-derived thin films resulted in a rapid, reagentless biosensor prototype that could monitor changes in pH due to the enzyme-catalyzed hydrolysis of triglycerides. These results demonstrate that species entrapped in sol-gel derived thin films are suitable for biosensor development.

abstract: Thesis

abstract: Master of Science (MSc)


title: Evidence of Longshore Drift in Beach Sediment: Manzanillo, Costa Rica

contributor:
Risk, M. J.
Geology

subject: longshore, drift, beach, sediment, Manzanillo, Costa Rica, grains, elements, mineral

abstract:
 The beach at Manzanillo, Costa Rica, is composed of a mixture of terrigenous siliciclastic and marine calcareous sediment. The most abundant siliclastic grains are magnetite and diopside. The most abundant calcareous grains are red algae and molluscan fragments. These grains are found in much greater abundance in the beach sediment then in their source areas as a result of their resistance to breakdown.

 The distribution of the siliclastic minerals on the beach shows longshore drift to be from east to west. The main source of siliclastic sediment is the Rio Sixaola. Local rivers provide small inputs of sediment.

 The trace element chemistry of the beach indicates the possibility that some elements may be absorbed on the surfaces of grains as opposed to being substituted for other elements in mineral lattices.

abstract: Thesis

abstract: Bachelor of Science (BSc)


title: Nonstatistical Inversion Dynamics of T-Shaped Ar3

subject: nonstatistical, inversion, dynamics, t-shaped, chemical

abstract:
 The objective of this research project was to study applications of statistical unimolecular reaction theories to a simple model chemical process. Such studies are needed to test the existing theories and provide direction for their further development. T-shaped Ar3, a simple chaotic two degree of freedom system, is an excellent candidate for such study, since statistical behavior is generally associated with chaotic dynamics.

 Chemical kinetics predicts fully statistical decay curves of microcanonical population associated with one of the two equivalent arrangements of T-shaped Ar3. However numerical computations, presented here, reveal nonstatistical characteristics of microcanonical T-shaped Ar3 inversion at energies associated with strongly chaotic dynamics. Nonstatisticality is most pronounced at higher energies where internal relaxation time scales are comparable to the inversion time. At such energies, population decay curves exhibit damped oscillations about the equilibrium population. At energies just above the inversion threshold, where inversion is very slow, near statistical nonoscillatory behavior is observed. The "absorbing barrier method" of J.E. Straub and B.J. Berne [J. Chem. Phys. 83, 1138 (1985)] is shown to provide a reasonable model for observed population decays. Characteristics of corresponding gap distributions are described in terms of an adapted "delayed lifetime gap model". Analysis of the model which combines the absorbing barrier method and the adapted delayed lifetime gap model provides insight into the observation of both oscillatory and nonoscillatory population decays. Specifically, the analysis describes the observations in terms of an "underdamped" or "overdamped" harmonic oscillator, respectively.

abstract: Thesis

abstract: Master of Science (MSc)


title: Preparation and Characterization of Temperature Sensitive Poly (N-Isopropylacrylamide) Microgel Latexes

contributor:
Pelton, R. H.
Chemical Engineering

subject: preparation, characterization, temperature, sensitive, microgel, latexes, particles

abstract:
 Temperature sensitive microgel latexes of poly (N-isopropylacrylamide) cross-linked with N-N'methylene bisacrylamide (BA) were prepared and characterized by Dynamic Light Scattering, Titration and Electrophoresis. The study of gels, including temperature sensitive gels, is limited by the large size of traditional bulk gels which are slow to respond to changes and are difficult to measure. An alternative system, which may be easier to study, is a microgel latex which would constitute small particles of gel which would respond quickly to changes in their environment and could also be measured using colloidal measuring techniques like dynamic light scattering and particle electrophoresis.

 Monodisperse and stable microgel latex particles were prepared by reacting Nisopropylacrylamide (NIPAM) monomer with a cross-linking agent BA in water at 70°C with a surfactant (sodium dodecylsulfate) present. Latexes prepared without surfactant were polydisperse.

 Characterization of the poly (NIPAM) particles by dynamic light scattering at several different temperatures showed that the particles go through a transition from a water swollen gel at low temperature to a shrunken gel with a low water content at high temperature. The transition occurs about 32°C. The degree of swelling of the poly (NIPAM) particles can be expressed by the Flory-Huggins Interaction parameter c and is dependent upon the level of cross-linking agent included.

 Titration and electrophoresis results indicate that the particles contain about 0.39 Coulombs per gram of polymer of carboxylic and sulfuric charged end groups which are distributed throughout the particle.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: Particle Path Determination in Large Ice Masses Using the Finite Element Method

contributor:
Stolle, D. F. E.
Civil Engineering

subject: particle, path, masses, finite, element, method, ice

abstract:
 A stream function finite element model is developed to solve for particle paths within a large ice mass. A steady-state primitive variable finite element model, treating ice as an incompressible non-Newtonian fluid, is used to furnish the necessary input velocities and rotations for the stream function finite element model. Time-integration along the particle paths is used to determine the age of the ice within the ice mass.

 Two ice masses are studied: the Barnes Ice Cap, Baffin Island, N.W.T., and Mount Logan, Yukon Territory. It is shown that if a realistic approximation of the velocity field of an ice mass can be established, the age of ice determined by time-integration along particle paths corresponds to the age determined by standard methods. Results of simulations using a transient model suggest that the elastic response of large ice masses is negligible.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: Poly(Methyl Methacrylate) Sterically Stabilized by Silicone

contributor:
Pelton, R. H.
Brook, M. A.
Chemistry

subject: sterically, stabilized, silicone, particle, formation, latex, nucleation

abstract:
 Nonaqueous poly(methyl methacrylate) latices were prepared by nonaqueous dispersion polymerization of poly(methyl methacrylate) in heptane in the presence of either trimethylsilyl terminated or vinyl terminated polydimethylsiloxane stabilizer. Poly(methyl methacrylate) particles stabilized by vinyl terminated polydimethylsiloxane showed smaller particle sizes than did those stabilized by trimethylsilyl terminated polydimethylsiloxane. Diameters of the various latex preparations ranged from 1.4 to 0.8 μm and silicone content was around 2 mole percent in each case. Differences between the two types of latex were explained in terms of the nucleation mechanism operating during the preparation of the latices and in terms of the type of attachment of the stabilizer chain to the poly(methyl methacrylate) core.

 The effect of the silicone concentration present during particle formation was investigated. Vinyl terminated polydimethylsiloxane stabilized latex gave better stabilized particles than did methyl terminated polydimethylsiloxane stabilized latex. The results of varying the concentration and type of initiator were consistent with the conclusions about differences in nucleation and grafting mechanisms.

 The stability of polydimethylsiloxane stabilized poly(methyl methacrylate) particles was investigated in n-heptane. Acidified montmorillonite clay was determined as the optimum catalyst for this latex system. Flocculation set in at 70% of the original silicone content when the siloxane on the particle surface was degraded with montmorillonite clay in a good solvent. Flocculation was irreversible and occurred abruptly. The point of flocculation was reproducible and the rate of flocculation was identical for two different types of silicone stabilized poly(methyl methacrylate) latex.

abstract: Thesis

abstract: Master of Science (MSc)


title: Structure and Properties of Lithium Ion Conductors in the Li2O-Y2O3-ZrO2 System

contributor:
Petric, Anthony
Materials Engineering

subject: structure, properties, lithium, ion, conductors, crystal

abstract:
 Ceramic samples of Li2+xYxZr1-xO3 with x=0 to 0. 1, Li8+xYxZr1-xO6 with x=0 to 0.2, Li1-xYxZr1-xO2 with x=0 to 0.5 and Li1+xZrxY1-xO2+x with x=0 to 0. 3 were prepared via conventional solid reactions. The solubilities, crystal structures and microstructures in these samples were studied by x-ray diffraction(XRD), infrared spectra, differential thermal
analysis(DTA) and scanning electron microscopy(SEM). The
results show that the solubilities are 0.05≤X<0.1 for Li2+xYxZr1-xO3 and Li8+xYxZr1-xO6,  0.1≤x<0.15 for Li1-xYxZr1-xO2, and x≥0.3 for Li1+xZrxY1-xO2+x, respectively. The crystal structures of the solid solutions of Li2+xYxZr1-xO3 and Li8+xYxZr1-xO6 are the same as Li2ZrO3 and Li8ZrO6, respectively but the cell constants change slightly with x, while the structure of Li1-xYxZr1-xO2 and Li1+xZrxY1-xO2+x changes from monoclinic for pure LiYO2 (x=0) to tetragonal (x≥0.005). The sinterability of Li2ZrO3 improves greatly with yttrium additions to Li2ZrO3.

 The conductivities of the samples were measured by
complex impedance spectroscopy and dc polarization. The results show that lithium conductivity in Li2+xYxZr1-xO3 samples increases slightly from 3.9x10^-6 to 5.0x10^-6 S/cm at 400°C as x increases from 0 to 0.05 and the corresponding conduction activation energy decreases slightly from 0.99 to 0.92 eV. Based on the effective medium theory, the conductivity increase in the solid solution was estimated to be 3% for x=0.05 compared with pure Li2ZrO3 crystal.

For Li8+xYxZr1-xO6 samples, a mixture of LiOH and Li2CO3,
which melts at about 430°C, can be formed during the processing and measurements. The ionic conductivity depends to a large degree on the microstructure(the amount and
distribution of the mixture) below 430°C. The lithium conductivity at 435°C increases from 1.0x10^-2 to 6.9x10^-2 S/cm as x increases from 0 to 0.05. The electronic contribution to
total conductivity is lower than 1% below 435°C.

 The ionic conductivity in the tetragonal phase of Zr-doped LiYO2 is much lower than in pure monoclinic LiYO2. The
conductivity values at 500°C are 1.3x10^-2 for pure LiYO2 and 1.2x10^-4 for Li1.3Zr0.3Y0.7O2.3. The ionic conduction activation energy in the tetragonal Zr-doped LiYO2 is much higher than pure LiYO2.

 The thermal stability and the hydrolysis tendency for Li2ZrO3, Li8ZrO6 and LiYO2 were examined by thermodynamic calculations and by experiments.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: The Observed Stability of PVC Particles in n-Butylchloride

contributor:
Woods, D. R.
Pelton, R. H.
Chemical Engineering

subject: stability, PVC, Particles, polymerization, aqueous, ion, exchange, particles, molecules

abstract:
 The mechanism by which PVC particles remained stable in n-butylchloride was investigated.

 The PVC particles were made by aqueous emulsion polymerization with benzoyl peroxide initiator and polyvinyl alcohol surfactant. The particles were cleaned by ion exchange and their surface charge was found to be 0.068 ± 0.005 C/m^2. Dispersions of PVC in n-butylchloride were prepared by two methods. In the first, the particles were dried in an oven. The dried particles were redispersed in n-butylchloride via sonication. This produced a dispersion consisting of 0.26 kg/m^3 of PVC particles with an arithmetic volume average diameter of 317 nm and a standard deviation of 93 nm. The second method involved dialyzing the cleaned aqueous latex with methanol and then with n-butylchloride. The dialysis method was inferior to the sonication method. The dialysis method was time consuming, it produced a dispersion with large particle diameter, the dispersion was contaminated with water and methanol and surface species were removed by the methanol.

 The particles were found to be stabilized by an electrostatic mechanism. This was verified by observing that the particles migrated to the positive electrode when exposed to a potential difference of 1000 V. A surface potential of 0.203 V was calculated for the particles from mobility measurements and the Huckel equation.

 The charge separation that must occur to allow the particles to have the negative charge is hypothesized to be a result of organic molecules such as PVC-PVA oligomers that dissolve from the particles and form micelles. These molecules were readily soluble in methanol and only slightly soluble in n-butylchloride. As a result, when the dispersion was washed with methanol, the particles flocculated. The presence of these species in the dispersant was supported by evidence from ultra-violet, infra-red and nuclear magnetic resonance spectroscopy. The electronegative groups in the micelles provide a reasonably polar environment for hydrogen ions to exist. These hydrogen ions became the countercharge for the negatively charged particles.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: Measuring the Properties of Polymer Latices Using High Frequency Longitudinal Stress Waves

contributor:
MacGregor, J. F.
Chemical Engineering

subject: properties, polymer, latices, high, frequency, longitudinal, stress, waves, concentrations, structures

abstract:
 There is a great need for sensors that can infer the properties of polymer latices. Measuring ultrasonic wave travel parameters through a latex and calibrating these against polymer properties is one potential technique for measuring the polymer properties of a latex without separating the polymer particles from water. Ultrasonic longitudinal waves can be characterized by three travel parameters: the velocity, the attenuation and the frequency. For colloidal systems the attenuation will depend on molecular properties of the system inside a frequency window where diffraction and scattering are negligible.

 In this thesis the equipment for measuring ultrasonic waves is discussed and a measurement cell for measuring waves in liquids is designed and built. This equipment is used to measure the velocity and attenuation as functions of frequency for two sets of copolymer latices. These latices were measured separately using a combination of standard quality control analyses and polymer characterization techniques. It was discovered that the velocity of sound through latices does not differ significantly from the velocity for pure water while the ultrasonic attenuation of latices at solids concentrations of greater than 10 percent is much greater than the value for pure water.

 For the copolymer latices produced from styrene and methyl-methacrylate the attenuation measurements were all too similar to distinguish between changes in the properties of the latex. For the copolymer latices produced from styrene and butadiene, the attenuation and composition were related by an approximately linear relationship between 30 and 80 mole percent styrene. In this region, the attenuation spectra were regressed onto the property space using a linear multivariate algorithm called projection to latent structures. It was found that the attenuation is only useful for predicting latex properties that are related to composition in this range. Future work should focus on the use of a non-linear regression technique to model the behaviour of attenuation over the entire composition range and the use of independent analyses to better characterize some of the polymer properties such as crosslinking.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: Real Time Analysis of Protein Adsorption

contributor:
Brash, J. L.
Chemical Engineering

subject: time, analysis, real, protein, adsorption, cell

abstract:
 An experimental method for monitoring the adsorption of proteins in real time has been developed and is the topic of this thesis.

 Proteins were radioactively labeled using 125I and injected at a constant flow rate into a well stirred glass cell containing buffer and the adsorbing surface in particle form. The buffer contained in the cell was gradually displaced by the protein solution. NaI(TI) detectors, coupled to a multichannel analyzer and high voltage power supply, were placed at the exit of the cell to monitor the radioactivity of the bulk solution. Adsorption of the protein was determined by depletion of protein in the bulk solution.

 A process to treat the surface of the cell and the glass tubing so as to
prevent adsorption was developed and implemented prior to the flow experiments. This procedure involved exposing the cell and glass tubing to a 1 mg/mL fibrinogen solution for two hours at room temperature. The cell and tubing were then placed in an oven for 10 minutes at 70° C. This procedure (referred to as the thermal treatment procedure) resulted in a non-adsorbing protein layer that appeared, from extensive experiments, to be irreversibly attached to the surface of the cell and tubing.

 The adsorption of fibrinogen from a single component system, as well as from plasma, was studied using the experimental arrangement described above. Concentrations of fibrinogen in isotonic Tris, for the single component system, ranged from 40 mg/mL to 300 mg/mL. It was found from these experiments that an initial, fairly rapid, adsorption of protein took place. Later the adsorption of protein slowed significantly.

 The adsorption and subsequent desorption of fibrinogen from diluted plasma was also studied. Dilutions ranged from 1% to 20%. The results from these experiments are consistent with the model proposed by Vroman for plasma surface interactions.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: A Forth Based Robotics Language

contributor:
Solntseff, N.
Computation

subject: forth, robotics, language

abstract:
Abstract Not Provided.
Thesis
Master of Science (MSc)


title: Using Digital Spectroscopy in the X-Ray Fluorescence Measurement of Lead and Mercury

contributor:
Chettle, David R.
Physics and Astronomy

subject: digital, spectroscopy, x-ray, fluorescence, lead, mercury, measurement, resolution

abstract:
 X-ray fluorescence has been used to measure levels of lead in the bone for many years. This technique is particularly important for the occupational monitoring of those exposed to lead in the workplace as it provides an indication of long term exposure and retention in the body. The measurement of kidney mercury by x-ray fluorescence has been developed recently and is currently being improved for future use in occupational monitoring.

 X-ray fluorescence detection systems conventionally employ analog-amplifier components. Recently, digital spectrometers have been developed which can replace these conventional electronics components. The digital systems offer higher throughput without major losses in resolution which translates to better precision and reduced detection limits for x-ray fluorescence measurements.

 Investigations using the DSPECplus and DSA-2000 digital spectrometers for the measurement of bone lead in phantoms showed significant improvements in precision and potential reductions in MDL compared to conventional electronics. The use of the DSA-2000 digital spectrometer in a bone lead survey was shown to improve measurement uncertainties for in vivo bone lead measurements. Investigations using the DSA-2000 for the XRF measurement of kidney mercury in phantoms also showed a significant reduction in MDL for this system by the introduction of digital spectroscopy.

abstract: Thesis

abstract: Master of Science (MSc)


title: Substitution Effects on the Photochemistry of 1,1-Diarylgermacyclobutanes and the Reactivity of Transient 1,1-Diarylgermenes

contributor:
Leigh, William J.
Chemistry

subject: substituent, photochemistry, reactivity, transient, state, germanium, compounds

abstract:
 1,1-Bis(4-(trifluoromethyl)phenyl)germacyclobutane and 1,1-bis(3,5-bis(trifluoromethyl)phenyl)germacyclobutane have been prepared, and their photochemistry studied by steady state and nanosecond laser flash photolysis (NLFP) techniques. Photolysis of the two compounds in the presence of methanol leads to the formation of products resulting from reaction of the alcohol with two germanium-containing reactive intermediates, the germenes and germylenes.

 The reactivities of the two germenes with nucleophiles such as alcohols, carboxylic acids, and amines have been examined by NLFP techniques, and the results are compared to analogous data for 1,1-diphenylgermene and 1,1-diphenylsilene. Germene reactivity is shown to increase with increasing electron-withdrawing power of the substituents, consistent with a mechanism initiated by nucleophilic attack at germanium. The increased electrophilicity of the substituted 1,1-diarylgermenes results in kinetic behavior indistinguishable from that of 1,1-diphenylsilene, indicating that germenes and silenes form a mechanistic continuum in their reactions with nucleophiles.

abstract: Thesis

abstract: Master of Science (MSc)


title: Investigation of Quantitative NMR by Statistical Analysis

subject: quantitative, NMR, statistical, analysis, mixtures, samples

abstract:
 Quantitation by nuclear magnetic resonance (NMR) has been frequently done with integrals. The use of peak heights has been thought to be unreliable. The aim of this thesis is to examine the reliability of peak height method in achieving quantitative NMR measurements for small molecules such as water and sucrose.

 Isotope measurements have been traditionally done by isotope-ratio mass spectrometry. This is no doubt a highly sensitive technique for analyzing pure samples but the analysis of mixtures is not as straight-forward as it would be for the former. Ontario Hydro has encountered problems in measuring deuterium in DMSO/water mixtures. To solve the problem with NMR, an analytical method has been established to measure the deuterium content in waters and in DMSO/water mixtures. This involved testing a linear model for analyzing waters which were enriched or depleted with deuterium as well as applying the model to quantify DMSO/water mixtures. Both 1H and 2H NMR were employed. Satisfactory accuracy and precision of the results were obtained.

 For quantitative 13C work, the peak height method is often not recommended due to the variations in signal width, which is a result of varied T2 values and nuclear Overhauser enhancement (NOE). Sucrose molecules in cane sugar and beet sugar have different 13C isotopic ratios because they are synthesized by different photosynthetic pathways. To see the usefulness and limitation of the peak height method, 13C spectra of sucrose were acquired and the carbon peaks were quantified. Good precision was achieved but no predictable trend in the isotope difference could be found.

abstract: Thesis

abstract: Master of Science (MSc)


title: ETHICAL EVALUATION IN HEALTH TECHNOLOGY ASSESSMENT

title: DEVELOPMENT OF A PROCEDURAL FRAMEWORK FOR INCORPORATION OF ETHICAL CONSIDERATIONS IN HEALTH TECHNOLOGY ASSESSMENT

contributor: Clinical Epidemiology/Clinical Epidemiology & Biostatistics

subject:
Health Technology Assessment
Ethics

abstract:
Background and objectives -
Addressing ethical issues in health technology assessment (HTA) can increase transparency and accountability of the HTA process and lead to better-informed healthcare decisions. Despite its importance, integration of ethics into HTA remains challenging. The objective of this thesis was to develop a process-based framework to support ethical evaluations in HTA and increase their applicability.

Methods -
Project 1: A systematic literature review was conducted with the purpose of identifying and mapping the methodological features of the existing frameworks for ethics in HTA.
Project 2: A systematic literature review and an international survey of HTA agencies were conducted to explore how ethical evaluations may be encouraged or discouraged in the HTA practice.
Project 3: A procedural framework was drafted based on the operational features of the identified guidance documents as well as barriers and facilitators for incorporating ethics into HTA.
Project 4: The framework was applied to a hypothetical case study, with the aim of helping HTA practitioners touch on key points of the steps outlined by the proposed framework.

Results - Project 1:  The identified ethical frameworks vary in their purpose, philosophical approach, structure, and comprehensiveness. The review results suggest that the choice of a method for collection and analysis of ethical data depends on the context, purpose of analysis, and availability of resources.
Project 2:  The results of this study emphasize the importance of simplification of ethics methodology and development of good practice guidelines in HTA, as well as capacity-building for engaging HTA practitioners in ethical analyses.
Project 3: The proposed framework consists of an algorithmic flowchart, showing different steps of an ethical evaluation throughout the HTA process; a stepwise guide, which focuses on the tasks and potential questions that are required to be addressed at each step; and a list of some commonly recommended tools to facilitate the evaluation process.
Project 4:  The case study outlines the key tasks, recommended by the framework, and provides examples of process outputs that could be considered when attempting to perform an ethical evaluation.

Conclusions -
The outputs of this thesis can be used to support and promote a more consistent practice of ethical evaluation among HTA professionals. However, further validation of the proposed framework is required to establish its utility for HTA practice.

abstract: Dissertation

abstract: Doctor of Philosophy (PhD)


title: PATTERN RECOGNITION AND CLASSIFICATION OF CT IMAGES OF DIFFUSE LUNG DISEASES USING FEATURE EXTRACTION AND ARTIFICIAL NEURAL NETWORKS

contributor:
Kamath, Markad v.
Computer Science

subject: Medical Image processing

abstract:
Diffuse Lung Diseases (DLD), impute to 15% of respiratory practice and are accountable for a large class of disorders, primarily affecting lung parenchyma. As a part of the diagnostic workup by the physician, a chest CT image is often required in addition to a thorough medical history and physical examination.  The reliable identification of the features among interstitial lung diseases and the patterns they may take is challenging, particularly given the volume of data on a CT scan that must be processed by the radiologist. It has been shown that even among expert chest radiologists there is significant inter-observer and intra-observer variability.
To make an objective quantitative and qualitative assessment of lung disease patterns, an accurate and reliable computer aided diagnostic system is likely to be extremely useful to assist with dealing with data volume for an expert radiologist. There will also be the opportunity to improve sensitivity and specificity in a non-expert radiologist group. Literature suggests that computer based pattern classifiers can discern image abnormalities due to lung diseases such as consolidation, cyst, emphysema, fibrosis, ground glass opacity, honey combing, nodularity, reticulation, scar and tree-in-bud.
Researchers have focused on developing algorithms to quantify and analyse the surface changes of the lung, since DLD patterns often manifest as texture differences within the lung parenchyma. Research reported in this thesis has incorporated texture quantification, fractal analysis and scale invariant feature transform methods as complementary feature extraction techniques to improve the classification accuracy, especially in the presence of large number of classes associated with interstitial diseases. Classification of ten lung pathologies and healthy lung regions are validated based on different combination of diseases using leave-one-out and 5-fold cross validation techniques and an Artificial Neural Network (ANN).
Classification accuracy based on features selected using scale invariant feature transform method alone generates 99% accuracy for up to four classes and more than 71% for up to eleven classes using an ANN. Classification accuracy is 85% for eleven classes using a combination of scale invariant feature transform, texture and fractal based features. Classification accuracies improve for higher number of classes (> 5) when the combination of above mentioned features are incorporated. Detailed classification accuracies for several DLD features compared to a healthy lung, and combinations of DLD features, such as fibrosis, reticulation, honey combing in comparison with healthy lung are evaluated throughout this thesis.

abstract: Thesis

abstract: Doctor of Philosophy (PhD)


title: Shear Strengthening of RC Beams Using Externally Bonded and Anchored FRP U-wraps

contributor:
Razaqpur, A. Ghani
Civil Engineering

subject:
FRP
U-wraps
Shear strengthening
Anchor
Reinforced concrete

abstract: Externally bonded FRP U-wraps are a common shear strengthening configuration for RC beams, however premature debonding of the wraps is a major problem, which limits the effectiveness and efficiency of the FRP strengthening. In this investigation a new π-shape carbon anchor was used to fasten the FRP U-wraps to the concrete in an attempt to prevent/delay debonding of the wraps and increase their effectiveness. Fourteen large scale rectangular beams with a 1900 mm span, 400 mm height, and 170 mm width were tested in three-point bending with various configurations of FRP shear strengthening. Shear pre-cracks were introduced in the beams at angles of 30 and 45 degrees in an attempt to control the inclination angle of the shear crack and determine its effect on the FRP shear resistance. The FRP shear strengthening configurations included un-anchored U-wraps, U-wraps with anchors, U-wraps with horizontal strips, and full wraps. The results showed that the use of a variable shear crack inclination angle in the CSA S806-12 (2012) standard led to overestimated shear resistance predictions for beams with a single shear crack, therefore a conservative 45 degree shear crack inclination is recommended for design. The use of the proposed carbon anchors resulted in a 74% increase in shear strength over the un-anchored U-wrapped beams, while only using half the amount of FRP. The use of the anchors also resulted in a 286% increase in the ultimate FRP strain over the un-anchored U-wraps, and allowed the FRP wraps to achieve 58% of their rupture strain. The use of horizontal strips provided similar results to the anchors and may be used as a less labour intensive alternative, but this issue needs further investigation.

abstract: Dissertation

abstract: Master of Applied Science (MASc)

abstract: Damaged or older reinforced concrete structures can be rehabilitated by using externally bonded fibre-reinforced polymer (FRP) sheets, which are bonded to the concrete surface using an epoxy adhesive. For the case of shear strengthening of beams, it is common for FRP sheets to be wrapped around the sides and bottom of the beam, resembling a U-shape. The problem with this configuration is that under high levels of load the FRP sheets tend to peel off the concrete surface (debonding). This limits the effectiveness of the rehabilitation and results in the inefficient use of the FRP. A new method for anchoring the FRP sheets to the concrete surface is investigated in this research study. The use of a new in-situ π-shape anchor shows promising results, as it delays debonding and provides a large increase in strength with less FRP needed.


title: The Photochemistry of 2-Trifluoromethylnorbornene and 7-Trifluoromethylbicyclo[4.2.0]Oct-7-Ene. Definition of π,π* and π,R(3S) Reactivity in the Photochemistry of Substituted Norbornenes and Alkylcyclobutenes

subject: photochemistry, reactivity, norbornenes, alkylcyclobutenes, absorption, spectroscopy

abstract:
 2-Trifluoromethylnorbornene has been synthesized from norbornene. The UV photoelectron spectra and optical UV absorption spectra of norbornene, 2-methylnorbornene and 2-trifluoromethylnorbornene have been studied, and indicate that the π,π* state is the lowest excited singlet state. Direct photolysis of 2-trifluoromethylnorbornene with 193 nm light yields 1-trifluoromethyl-2-norcarene (in 90% yield) by formal [1,3]-sigmatropic rearrangement. Chlorobenzene-sensitized photolysis affords the photoreduction products, exo-and endo-2-trifluoromethylnorbornane, decane isomers, and several products of higher molecular weight.

 By comparing the photochemistry of 2-trifluoromethylnorbornene to those previously reported for norbornene and 2-cyanonorbornene as well as on the basis of spectroscopic evidence, it is proposed that the π,π* state is the lowest energy excited singlet state in 2-trifluoromethylnorbornene. Trifluoromethyl substitution has the effect of significantly raising the energy of the π,R(3s) Rydberg state in simple alkenes without altering the high energy or the localized character of the π,π* state.

 7-Trifluoromethylbicyclo[4.2.0]oct-7-ene (86) was synthesized from bicyclo[4.2.0]oct-7-ene (84). By comparing the UV photoelectron spectroscopy and optical spectra of 86, 84, 97, it is concluded that the π,π* state is the lowest excited singlet state in 86. Direct photolysis with 193 nm light yields three diene isomers derived from formal electrocyclic π,π* ring opening, and cyclohexene derived from fragmentation. Comparison of spectroscopic and photochemical results for this compound to those of bicyclo[4.2.0]oct-7-ene (84) and 7-methylbicyclo[4.2.0]oct-7-ene (97) indicate that ring-opening is non stereospecific and arises largely from the π,π* singlet state. Fragmentation arises largely from the Rydberg excited state.

abstract: Thesis

abstract: Master of Science (MSc)


title: Discrete Geometric and Predictive Nonlinear Control

subject: discrete, geometric, nonlinear, control, predictive, matrix, trajectory, controller

abstract:
 The topic of study within includes the development and application of nonlinear control technologies on sampled systems. Discrete control structures are introduced that expand on existing differential geometric and predictive control methods. The differential geometric techniques are described from the error trajectory context, which are typically only derived for continuous application. The discrete error trajectory controllers introduced have one of two configurations. The first configuration requires satisfaction of the error trajectory objective at the next sampling interval through prediction of system behaviour over the controller sampling interval. This objective found limited success and it is observed that satisfaction of the error trajectory objective at discrete intervals does not generally result in the intended response. The second configuration minimizes the integrated distance from the error manifold defined by the error trajectory objective over the entire controller sampling interval. It is observed that this integrated error trajectory controller best emulates the intent of the continuous controller in the discrete domain. Techniques borrowed from predictive control are incorporated into the integrated error trajectory controller such as input move suppression and constraints to produce an optimal error trajectory controller, further improving performance.

 The predictive control method introduced utilizes a transformation of the input space. The differentiating property of input transformation predictive control (ITPC) from other methods is the prediction technique that is capable of estimating the future behaviour of nonlinear systems through elementary matrix operations similar to the dynamic matrix control (DMC) prediction technique. This is achieved by separation of the steady state and dynamic system properties and the introduction of an intermediate state prediction layer. This allows for the nonlinear prediction of system behaviour without the need to numerically integrate the system model.

 Two example systems are used to demonstrate application of the discrete error trajectory and ITPC on nonlinear controllers. Performance for these control structures is compared to technologies accepted within the control community for a broad range for characteristics including, computation efficiency, design effort and other nonlinear performance criteria, with favourable results.

abstract: Thesis

abstract: Master of Engineering (MEngr)


title: Applications of Single Selective Inversion DNMR

contributor:
Bain, A. D.
McGlinchey, M. J. M.
Chemistry

subject: single, selective, inversion, DNMR, applications, temperatures, isomerization

abstract:
 The single selective inversion recovery experiment, developed by Bain and Cramer, has been used with great success in elucidating the molecular dynamics of three systems.

 The isomerization of d,l bis(1-indenyl)dimethylsilane to its meso isomer proceeds through sequential [1,5]-suprafacial shifts; ΔH+ for the process was evaluated as 21.9 ± 0.5 kcal/mol. There is only one mechanism operating at a detectable rate below about 150°C. Below 100°C this process is too slow to be detected by DNMR, but it is readily followed by classical kinetics methods. Above 100°C, the isomerization may be followed by 1D selective inversion experiments. The isoindene intermediate is conveniently trapped as its double Diels-Alder adduct showing that the rearrangement occurs relatively rapidly on the chemical time-scale.

 The barrier to hindered rotation about the Mn - C(4) sigma bond in (n^1 -Cpp)Mn(CO)3(PEt3)2 was measured. The observed value of ΔH+ was 13.1 ± 0.2 kcal/mol. ΔS+ was determined to be -11.2 ± 0.7 eu. As the compound is thermally sensitive, it would have been impossible to use lineshape analysis to determine the barrier. 1D selective inversion recovery experiments were used.

 A combination of 13C NOESY, 13C single selective inversion, and 13C lineshape analysis experiments identified the exchange pathways and determined temperature-dependent rate constants for the N,N'-[dimethyl-(2,2'dithiobisacetyl)]ethylenediamine (DADS) system. DADS exists as five exchanging rotamers in solution. Two of the conformers are symmetric, with C2 symmetry (ZZ1 and ZZ2). The other three conformers are asymmetric, with one amide group cis and the other trans (ZE1, ZE2, ZE3).

 The NOESY experiments gave a site-to-site map of the exchange processes at several temperatures. At room temperature, ZE1 is exchanging with both ZE2 and ZE3, but there appears to be no exchange between ZE2 and ZE3. This process seems to occur via hindered rotation about the disulfide bond, with ΔH+ = 15.3 ± 0.4 kcal/mol, and ΔS+ = -6.3 ± 1.1 eu.

 At higher temperatures, ZZ1 and ZZ2 start to exchange with ZE1 via hindered rotation about the amide bonds. ΔH+ for the process was determined to be 19.8 ± 0.4 kcal/mol, and ΔS+ was found to be 0.7 ± 1.2 eu. The barrier agrees quite well with that measured for the uncyclized precursor to DADS. ΔH+ was found to be 19.3 ± 0.7 kcal/mol, while ΔS+ was determined to be 2.5 ± 2.1 eu.

abstract: Thesis

abstract: Master of Science (MSc)


title: A Study of Two Dimensional NMR Using the Superspin Formalism

contributor:
Bain, A. D.
Chemistry

subject: dimentional, two, NMR, superspin, formalism, bilinear, BIRD, interpulse

abstract:
 Two-dimensional C-H chemical shift correlation spectroscopy provides a large amount of information in a two dimensional matrix. Many variations of these experiments have been in an effort to enhance the information content of these experiments. Decoupling of multiplet signals is one method used to increase the sensitivity of an NMR experiment. Simple broadband decoupling in ω2 is done by irradiating the correlated channel during acquisition. Decoupling in ω1 must be done using less direct methods, one of which is to use bilinear rotation decoupling. The traditional description of the effect that a BIRD pulse has on the spin systems is based on a simple AX system which is at equilibrium at the beginning of the pulse, which does not apply in many real systems.

 This study uses the Superspin formalism to show in more detail the behaviour of more complex spin systems during the BIRD sequence, and the effect of varying parameters within the BIRD sequence. This treatment involved the derivation of complete spherical tensor descriptions of AX, AX2, and AX3 spin systems. This allowed the derivation of a mathematical description of an INEPT style pulse sequence, where the refocussing pulse in INEPT was replaced with the BIRD sequence. The derivation of the general evolution transformations of the spherical tensors in Liouville space also allowed the theoretical treatment to be done in a single basis, where earlier implementations of the Superspin formalism converted between a spherical tensor basis for the treatment of pulses and a Hamiltonian basis for the treatment of delays. This theoretical treatment allows the derivation of a functional form for the dependence of the carbon signal intensity on the variation of the interpulse delay in the BIRD sequence.

 This formalism was also used to analyze the occurrence of artifacts in two dimensional heteronuclear shift correlation spectra, due to strong coupling between methylene protons. These artifacts were studied in experiments that attempt broadband homonuclear decoupling in ω1 through the use of constant evolution time between the initial excitation pulse and polarization transfer. Two experiments were analyzed, the COLOC experiment and the HETRES experiment. The superspin formalism was used to deduce a functional form for the intensity of the artifact as a function of the strength of the coupling between the methylene protons.

abstract: Thesis

abstract: Master of Science (MSc)


title: Tunable Diode Laser Diagnostics in Photochemistry

contributor:
Reid, J.
Physics

subject: tunable, diode, laser, diagnostics, photochemistry, lead-salt, molecular, chloroform

abstract:
 A detailed experimental and theoretical study has been performed on several different photochemical systems. Lead-salt tunable diode lasers operating in the infrared region have been used as diagnostic tools to probe the molecules in these gaseous systems. Knowledge of these systems is expected to be useful in evaluating future schemes of laser isotope separation.

 In the course of this work a computerized digital technique has been developed that allows molecular parameters such as linestrength and linewidth to be obtained by measuring the infrared absorption on vibrational-rotational transitions of the molecule. Molecular concentrations can then be determined enabling one to gain valuable insight into the chemical processes occurring in the system.

 The digital technique was first tested on CO2 gas in a multi-pass White cell to verify the validity of the measurements. Subsequently, measurements were performed on mixtures of NH3/N2, NH3/Ar, HTO/H2O, and HTO/air. Those NH3 measurements that could be compared to previous measurements were found to be very accurate. For the HTO system, no previous measurements on linestrength and linewidth for the transitions examined have been performed.

 Described next is the application of the tunable diode laser diagnostic system to the investigation of infrared multiphoton dissociation of deuterated chloroform immersed in a chloroform bath. The sensitivity of the technique allowed for the measurement of the few parts per million of DCl formed by the photolysis of natural abundance CDCl3 in CHCl3.

 In addition, the feasibility of transient detection with tunable diode lasers was examined. High fluence CO2 laser pulses were used to dissociate C3F6 or C2F3Cl and create CF2 radicals. Current-modulation of the tunable diode laser made it possible to monitor the transient CF2 radicals as they were formed, and as they subsequently decayed. The sensitivity of the transient detection technique was found to be limited by detector noise.

abstract: Thesis

abstract: Master of Science (MSc)


title: Simplex Optimization by Advance Prediction in Instrumental Neutron Activation Analysis

contributor:
Burgess, D. D.
Chemistry

subject: simplex, optimization, prediction, neutron, activation, analysis, instrumental, decay, interference

abstract: Though Neutron Activation Analysis is one of the most sensitive multielement analysis methods, Compton interference in complex sample matrices usually presents a problem when choosing irradiation and decay times for analysis. While various scientists have attempted to solve the problem, the approaches taken to date have the drawbacks of either requiring standard spectra of the sample components or not giving the optimum times automatically and simultaneously. The purpose of this thesis was to find a method to automatically and simultaneously obtain the optimum times for Instrumental Neutron Activation Analysis using the Modified Simplex Method to evaluate the best figure of merit calculated from an advance predicted spectrum of the sample.

abstract: Thesis

abstract: Master of Science (MSc)


title: Context: Much ado about - what, exactly?

contributor:
McConnell, Meghan
Health Science Education

subject:
Simulation
Paramedic
Context
Grounded Theory

abstract:
Introduction

Simulation-based learning is an example of learning in context in which clinical contexts are recreated in controlled settings to facilitate deliberate practice.  While widely regarded as effective, unanswered questions exist about what elements of the clinical context must be recreated in simulated settings to promote authenticity.  Moreover, the degree of authenticity (or fidelity) required for optimal learning is not known, with current thinking often deemphasizing the importance of physical realism. We therefore sought to explore contextual influences on performance in a ‘context-rich’ clinical setting: paramedicine.

Methods

We followed constructivist grounded theory principles and recruited currently practicing paramedics to participate in one-on-one, semi-structured interviews.  We asked the participants to describe a recent experience in which they attempted to resuscitate a victim of sudden cardiac arrest and asked them how to recreate their experiences in simulated settings.

Results

Fourteen paramedics provided a total of seventeen interviews, each describing a distinct cardiac arrest event, yielding over ten hours of audio data for analysis.  We iteratively identified three major interrelated themes describing contextual influences: the event – its physical characteristics, circumstances and people present; the conceptual response – the cognitive processes and challenges encountered; and the emotional response – the degree of emotional engagement in the management of the resuscitation.  We also identified a major theme related to how to simulate these events.  Collectively, our results suggest a complex and dynamic interplay between the physical, conceptual and emotional domains of context.

Conclusion

In contrast to other conceptualizations of context and fidelity, our results suggest that conceptual and emotional responses occur as a result of physical features in the practice environment, arguing in favour of physical authenticity in simulation.

abstract: Thesis

abstract: Master of Science (MSc)

abstract: Educators in the health professions have the important task of preparing their students – future physicians, nurses, paramedics, etc. – to perform effectively in clinical practice.  This transition from healthcare student to healthcare professional is challenging, in part because classrooms and clinical contexts are different entities: the environment, the people within it, the way knowledge is generated, recalled and applied are all different.  To narrow the gap between classroom and clinical practice, educators often promote learning in context, using various strategies to make the classroom more like the clinic (or any other setting in which health care is delivered).  The challenge, however, is that exactly what features of the practice setting (context) should be recreated to promote learning is not known.  We undertook this study, viewing the clinical context through a paramedic lens, to better understand what features present in real world conditions might influence learning and performance.


title: Brillouin Scattering Investigation of Glass-Like Properties in (KBr)1-x(KCN)x Mixed Crystals

contributor:
Walton, D.
Physics

subject: Brillouin, scattering, glass-like, mixed, crystals, properties, phonon, concentration, density

abstract:
 Brillouin scattering technique is used to investigate the transverse acoustic phonon in (KBr)1-x(KCN)x alloy as a function of temperature for CN- concentration ranging from 0.20 to 0.50. Anomalies in phonon frequency and linewidth are observed and discussed in terms of coupling of the acoustic phonons with orientational motion of CN- ions based on a dynamic microscopic model suggested by Michel et al. The frequency and concentration dependence of the freezing temperature, which marks the formation of an orientational glass state, is examined.

 A high resolution tandem Fabry-Perot interferometer yields the first evidence of a complex spectrum which consists of the phonon peak and new equal-spaced modes. The Bayesian deconvolution technique is used to extract the spectra. The concentration, time and temperature dependence of these new modes are presented. It is proposed that they arise from the modification of the tunneling levels of the CN, and appear to have the uniform density of states which is the characteristic property of the glass.

abstract: Thesis

abstract: Master of Science (MSc)


title: An Apparatus for the Study of the Volatilization of Iron Species with Pentanediketone Ligands

subject: apparatus, volatilization, iron, species, ligands, thermoradiometry

abstract: An apparatus was designed and built to enable the study of volatilization reactions using a novel variant of thermogravimetry called thermoradiometry. The usefulness of the apparatus was demonstrated by investigating the volatilization of iron from solid samples with the fluorinated ligands 1,1,1-trifluoro-2,4-pentanedione and 1,1,1,5,5,5-hexafluoro-2,4-pentanedione.

abstract: Thesis

abstract: Master of Science (MSc)


title: X-Ray Absorption Spectroscopy of Pd40Ni40P20 Metallic Glass and Boron Doped Silicon

subject: absorption, spectroscopy, metallic, glass, boron, doped, silicon, probe

abstract:
 Ni K extended X-ray absorption fine structure spectroscopy recorded with synchrotron radiation at 77 K and 300 K, has been used to investigate various annealed Pd40Ni40P20 metallic glass samples. The structural parameters (radial distance, coordination number, Debye Waller factor) for the Fourier filtered first coordination shell were obtained via curve analysis using MFIT (multifitting analysis) and plotted as a function of annealing temperature. Similar trends between 77 K and 300 K data were not observed in all cases. These results lead one to believe that the curve fitting procedure is not yet optimized and makes one sceptical of attributing any meaning to the results.

 X-ray absorption near edge spectroscopy via electron yield detection has also been used to study the B K edge in boron doped silicon. It was found that a strong peak at 195 eV is directly related to trigonally coordinated boron. Non trigonally coordinated boron did not seem to produce this spike. Results show that B 1s spectroscopy is a very sensitive probe of the local structure of boron.

abstract: Thesis

abstract: Master of Science (MSc)


title: An Induced Torque Study of Hg3-δAsF6

contributor:
Datars, W. R.
Physics

subject: induced, torque, resistivity, Fermi, surface, magnetic, direction

abstract:
 Under certain conditions, an induced torque measurement is a measure of the ratio of the resistivity to the square of the Hall constant. Induced torque measurements can be directly related to the connectivity of the Fermi surface.

 A modulation technique for measuring induced torque is justifield theoretically, and an instrument employing this technique is characterized. Operational limitations on parameters such as sample
resistivity and modulation rate are specified. A new procedure is proposed to extract more information from induced torque measurements. This procedure would allow the measurement of resistivity and Hall constant of ellipsoidal samples. The procedure is untested but appears to be feasible.

 Observations of the induced torque of Hg3-δAsF6 show that the Fermi surface supports an open orbit in one direction. This is discussed in the context of a model (Razavi et al., 1979), which has Fermi surface cylinders of common direction. This is based on conduction in Hg chain directions, which lie in only two directions. At magnetic fields greater than 3.0 Tesla, magnetic breakdown is observed. A Brillouin zone constructed using Hg chain symmetry and crystal parameters yields reciprocal lattice vectors compatible with the observed magnetic breakdown. The model is confirmed but a refinement is needed to allow an undulation of the Fermi surface cylinders.

abstract: Thesis

abstract: Master of Science (MSc)


title: A Structural Study of the Lithium Intercalates of RuO2, IrO2, and OsO2

contributor:
Greedan, J. E.
Chemistry

subject: structural, lithium, intercalates, diffraction, phases, orthorhombic, cells, neutron

abstract:
 The insertion of lithium into the rutile structures RuO 2 and IrO2 was found, by X-ray powder diffraction, to result in the formation of the orthorhombic phases Li0.9RuO2
and Li0.9IrO2, respectively. The orthorhombic cells of the intercalation products are related to the tetragonal transition metal dioxide cells by a large expansion (~ 0.5 Å) in the [100] and [010] directions and a smaller contraction (~ 0.3 Å for Li0.9RuO2 and 0.05 Å for Li0.9IrO2) along the [100] axis. Both LixRuO2 and LixIrO2 are two phased systems over the range of lithium compositions studied (0.2 <~ x <~ 0.9).

 The structure of Li0.9RuO2 was determined by neutron powder diffraction. The structure adopted by Li0.9RuO2 is a distorted NiAs-type structure quite similar to that of a related compound LiMoO2. Unresolved difficulties were encountered in attempting to prepare samples of LixOsO2 and LixIrO2 suitable for their structure determination.

abstract: Thesis

abstract: Master of Science (MSc)


title: Heavy Metal Removal From Wastewater Using Microbial Electrolysis Cells

contributor:
Kim, Younggy
Civil Engineering

subject:
Heavy metal removal
Bioelectrochemical systems
Cadmium
Lead
Microbial electrolysis cells
removal mechanisms

abstract: Heavy metal contamination in water is a serious environmental and human health issue. Lead (Pb2+) and cadmium (Cd2+) are strictly regulated in wastewater effluent due to their high toxicity at low concentrations. Heavy metals are difficult to remove in conventional biological wastewater treatment because they are water soluble and non-biodegradable. Advanced treatment, such as tight membrane filtration and ion exchange, can be applied but they often require a high electrical energy input and a large amount of chemicals for pre- or post-treatment. Microbial electrolysis cells (MECs) can be used to treat wastewater while simultaneously recovering energy in the form of hydrogen gas. Additionally, MECs were proven to be effective for heavy metal removal. The commonly investigated removal mechanism for heavy metals in MECs is reduction at the cathode where heavy metal ions are reduced to metallic solids. The research presented in this thesis examined the effectiveness of cathodic reduction and other heavy metal removal mechanisms in MECs over a wide range of metal concentrations (10 μg/L-12 mg/L). Lab-scale MEC operation demonstrated successful removal of both Pb2+ and Cd2+ under different electric conditions, operation times, and initial metal concentrations. In addition to cathodic reduction, heavy metal removal in MECs was demonstrated through chemical precipitation at the cathode and electrochemical reduction and biosorption at the bioanode. The results of this research also confirmed the importance of microbial activity at the bioanode to efficiently drive the removal mechanisms in MECs.

abstract: Thesis

abstract: Master of Applied Science (MASc)


title: Lewis Acid Catalysed Photochemistry of Carbonyl Compounds

contributor:
Childs, R. F.
Chemistry

subject: lewis, acid, catalysed, photochemistry, carbonyl, compounds, unsaturated, bond, reactions

abstract:
 This thesis describes an investigation into the effects of Lewis acid complexation on the photochemistry of α,β unsaturated carbonyl compounds.

 Initial studies involved the use of Nuclear Magnetic Resonance (NMR) and Ultraviolet (UV) spectroscopy in examining Lewis acid modification of the photostationary state for E/Z isomerization of various acyclic enones. The results obtained provide a good understanding of the origin of the perturbation of the photostationary state of these systems. In the course of these investigations, the question also arose as to the possible effects of complexation upon the photochemistry of cyclic enone systems where E/Z isomerization cannot occur, particularly whether this would catalyze [2+2] cycloadditions to the enone carbon/carbon double bond. Lewis acid complexed enones are widely used as activated dienophiles in Diels Alder reactions, and have been recently reported to serve as activated 'enophiles' in a photochemical dimerization of coumarin.

 The examination here is focused upon endo-tricyclo [5.2.1.02,6] deca-4,8-dien-3-one. (See Diagram in thesis).

 Reported here is a detailed investigation of the photochemistry of the AlEtCl2 complex of this compound, and the results are interpreted mechanistically. The reaction gives rise to a single product which reaches a photostationary state with the reactant complex. The isomerization is formally a [1,3] sigmatropic shift involving the isolated double bond. It seems likely however, to proceed by the formation of an allyl cation intermediate.

abstract: Thesis

abstract: Master of Science (MSc)


title: The Level Structure of 163Lu

contributor:
Waddington, J. C.
Physics

subject: level, structure, nucleus, reaction, coincidence, rotational, band, critical, frequencies

abstract:
 The level structure of the Odd-A nucleus 163Lu has been studied by the 148Sm (19F,4n) 163Lu reaction through gamma-ray singles and gamma-gamma coincidence methods.

 A number of rotational band structures have been observed up to a spin of 43/2. The backbending behaviour of the two signatures of the h11/2 band, α = -1/2 and α = 1/2, has been observed. The critical frequencies for the backbends are wc = 0.264 and 0.284 respectively.

abstract: Thesis

abstract: Master of Science (MSc)


title: Controlled Formation of New Si-Based Polymeric Materials

contributor:
Brook, Michael A.
Chemistry

subject: controlled, formation, polymeric, materials, reactivity, silicone

abstract:
 This thesis provides examples of new Si-based polymeric materials in three parts.
The rapid evolution of hydrogen gas was observed after the combination of an α- or β-hydroxy carboxylic acid with an alkoxyhydrosilane. This unusual reactivity is interpreted to arise from the cooperative nucleophilic attack of the hydroxy group at silicon and the electrophilic attack of the acid proton at the Si-H bond. These systems further react to produce modified sol-gel materials in which the acid units were incorporated into the matrix.

 The reactions of tetraethoxysilane, (TEOS) and α-hydroxy acids similarly produced modified sol-gels (in solution, DMSO) and solids (precipitated from THF). The reaction kinetics were followed in these systems using 29Si NMR. Extensive characterisation of our sol-gels was carried out by the use of various NMR techniques, FT-IR, elemental analysis and thermal methods of solids characterisation (TGA, DTA, and DSC).

 Silicones containing vinylsilane units were prepared in order to examine the silicon β-effect in a polymeric system for the first time. The addition of bromine to these systems unexpectedly resulted in no reaction unless vigorous conditions were used. Steric factors as shown by molecular modeling are attributed to this lack of reactivity. Although many silicone systems were studied where more sterically "open" vinylsilanes were present these steric problems could not be overcome.

abstract: Thesis

abstract: Master of Science (MSc)