<p> Nepheline syenite samples were collected from the Bancroft and Blue Mountain areas, Ontario, Canada, and were analysed for K, Rb, and Tl contents by atomic absorption spectrophotometry. The results for these elements and the corresponding K/Rb, K/Tl and Rb/Tl ratios were compared with those of nepheline syenites in various localities, and were found to be similar.</p> <p> The Tl, Rb, K contents and the K/Rb, K/Tl and Rb/Tl ratios in this study were determined to be 825 ppb, 110 ppm, 3.28%, 298, 4.11x10^4 and 135 respectively for the Bancroft nepheline syenite gneisses, and 574ppb, 93ppm, 3.28%, 353, 5.71x10^4 and 162 respectively for the Blue Mountain nepheline syenites. From these data, the nepheline syenite rocks in this study were probably originated as continental plutonics.</p> / Thesis / Bachelor of Science (BSc)

<p> This thesis represents a detailed assessment of the McMaster KN Accelerator site for the performance of a nuclear resonance absorption and fluorescence phenomenon in the 28Si nucleus. The main focus of this work is the 27Al(p, γ)^28 Si reaction, although other nuclear reactions are explored, such as: 27Al(p, p'γ)^27Al and 27Al(p, αγ)^24Mg. The gamma yield experiments from all these reactions suggest a repeatable and steady results, as well as very good agreement with the present literature. This is seen in chapter 2. Chapter 3 represents concrete nuclear resonance experiments with a direct ground state transition of the 12.33 MeV gamma energy from the 27Al(p, γ)^28Si reaction. These experiments are reproducible and repeatable with either HPGe or NaI(T1) (NaI elsewhere in text) detectors. Also, they are in close agreement with the literature.</p> <p> However, the main part of this work is described in chapter 4, where the first excited level of Si at 1.78 MeV is studied thoroughly. This is a pilot work that has never been attempted before. A thorough empirical approach is undertaken and described in section 4.1. This approach describes rationale for attempting nuclear resonance experiments with the first excited state of Si. The calculations suggest very close agreement between 12.33 MeV and 1.78 MeV experiments. Based on that, 7 different experimental sets, with several subsets ( within some of the sets) are performed. Very interesting results are obtained. However, so far, it cannot be concluded whether NRA/NRF experiments can be performed using the first excited state of Si. Most likely, hight current proton accelerators should be used and the experiments with 1.78 MeV lines should be repeated. These accelerators are described in chapter 5 and have the proton current output close to 1000 times higher than the McMaster KN accelerator. At the end, the dosimetry measurements suggest a negligible radiation dose from KN accelerator, as well as from these powerful accelerators.</p> / Thesis / Doctor of Philosophy (PhD)

<p> Measurements of the infrared absorption spectra of potassium and sodium halide crystals with substitutional H- ion impurities are presented and compared with calculations which use rigid ion and ordinary shell models for the defect along with phonon data obtained from inelastic neutron scattering measurements. It is shown that the shell model is necessary to give a satisfactory account of the observed anharmonic side band absorption in the sodium halide crystals and that it improves the rigid ion results for the potassium halide crystals. The same model also satisfactorily describes the impurity induced far-infrared absorption in these materials. Some Van Hove singularities observed in the far infrared measurements occur at frequencies predicted from phonon densities of states calculated from neutron scattering data while others occur at slightly different frequencies.</p> / Thesis / Doctor of Philosophy (PhD)

<p> 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.</p> <p> 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.</p> <p> 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.</p> / Thesis / Master of Science (MSc)

<p> The optical absorption in manganese fluoride has been studied in the range of 30 to 300 cm^-1 with emphasis placed on the possible multiple magnon absorptions (other than two-magnon) and an induced single magnon absorption. It is shown that theoretically one can expect four-magnon processes by expanding the Heisenberg spin hamiltonian to higher orders in the creation and annihilation operators introduced by the Holstein-Primakoff transformation. However, neither an induced one magnon nor four magnon process was observed. The absorptions which were seen in the spectra were attributed to phonon processes.</p> / Thesis / Master of Science (MSc)

The present apparatus was used to obtain rate data for the absorption of oxygen in a catalysed liquid phase reaction with acetaldehyde. The effects of several system parameters, namely, acetaldehyde concentration, catalyst concentration, partial pressure of oxygen and temperature on the rate of absorption were studied. An attempt was made to correlate absorption rates and product distribution with mathematical models based on the film theory and existing kinetic models proposed by Bolland and Bawn. Absorption rates predicted by these semi-empirical correlations are compared with experimental values. The differential equations involving diffusion with chemical reaction were solved on the digital computer IBM 7040 and the analog computer PACE TRlO. / Thesis / Master of Engineering (MEngr)

Quantum coherence and interference (QCI) is a phenomenon that takes place in all multi-level atomic systems interacting with multiple lasers. In this work QCI is used to create several interesting effects like lasing without inversion (LWI), controlling group velocity of light to extreme values, controlling the direction of propagation through non-linear phase matching condition and for controlling the correlations in field fluctuations. Controlling group velocity of light is very interesting because of many novel applications it can offer. One of the unsolved problems in this area is to achieve a slow and fast light which can be tuned continuously as a function of frequency. We describe a method for creation of tunable slow and fast light by controlling intensity of incident laser fields using QCI effects. Lasers are not new to the modern world but an extreme ultra-violet laser or a x-ray laser is definitely one of the most desirable technologies today. Using QCI, we describe a method to realize lasing at high frequencies by creating lasing without inversion. Role of QCI in creating correlations and anti-correlations, which are generated by vacuum fluctuations, in a three level lambda system coupled to two strong fields is discussed.

In architectural design, few materials compare to the degree of use of concrete. Due its high compressive strength and economic efficiency, concrete excels in architectural applications. While impressive, concrete has shortcomings in its acoustic absorption properties and ability to be used sustainably. To address both concerns, the proposed solution is to introduce waste wood fibers into concrete's composition. Due to wood's fibrous nature, acoustic absorption can be bolstered while improving sustainability by recycling waste wood products. While manufacturing wood infused concretes and measuring acoustic absorption is not difficult, it is time consuming and resource intensive. Therefore, a model to estimate acoustic absorption coefficients of fiber-infused concretes is developed to aid in bypassing the need for experimental trial-and-error. The model utilizes the Delany-Bazley (DBz) and Johnson-Champoux-Allard-Lafarge (JCAL) models to predict acoustic absorption coefficients of given fiber-infused concretes. The DBz model provides an estimate of the characteristic impedance and wave number of a sample based on a power-law relationship that considers sound medium and airflow resistivity. The DBz model estimates are then refined by the JCAL model using estimated viscous and thermal properties of the sample. Finally, using these refined acoustic property estimates, the acoustic absorption coefficients are estimated. Using varying wood-infused concrete samples, results are experimentally verified using an impedance tube and absorption coefficients are calculated using the transfer-function method. After comparing estimated and measured absorption values, the current model was found to have the potential of providing a relative comparison of acoustic performance between compositions. However, estimated values were not accurate, nor considered representative of samples. Further, multiple aspects of the model could be improved to better represent different concrete compositions in model estimations.

Bispyribac-sodium is an acetolactate synthase (ALS) inhibiting herbicide introduced for control of grasses, broadleaves, and sedges in rice and turf. However, Mississippi and Arkansas rice producers have reported inconsistent barnyardgrass (Echinochloa crus-galli Beauv.) control with bispyribac-sodium. Experiments were conducted to determine if inconsistent barnyardgrass control with bispyribac-sodium could be alleviated through adjuvant technology. Absorption of 14C-bispyribac-sodium was greatest with a proprietary blend of methylated seed oil/organosilicone (MSO/OSL) (0.37 L ha-1) plus urea ammonium nitrate (UAN) (2% v/v) and the proprietary blend of MSO/OSL/UAN (2% v/v) at 80 and 74% of applied 14C-bispyribac-sodium, respectively. The addition of 32% UAN to MSO/OSL and non-ionic organosilicone (OSL/NIS) adjuvant systems resulted in a four- to fiveold increase in absorption compared to treatments without UAN. Maximum absorption was achieved 12 h after application and therefore, bispyribac-sodium should be rainfast at this time. MSO/OSL adjuvants supplied from multiple manufacturers were also examined to determine which provided the highest levels of 14C-bispyribac-sodium absorption as well as herbicidal efficacy and rainfastness. The addition of Rivet® plus UAN or Sil-MES 100® plus UAN to 14C-bispyribac-sodium resulted in the highest levels of absorption among adjuvants supplied. Bispyribac-sodium applied with no adjuvant or with 32% UAN only resulted in significant reductions in control compared to MSO/OSL adjuvant formulations. Addition of MSO or MSO/OSL adjuvants and UAN to bispyribac-sodium resulted in greater than 85% freshweight reduction of barnyardgrass. Bispyribac-sodium applied with MSO or Dyne-A-Pak® was rainfast by two and four hours after application, respectively. Addition of Sil-MES 100® plus UAN or Inergy® plus UAN to bispyribac-sodium reduced the rainfastness interval to 30 minutes and one hour after herbicide application, respectively. Further experiments were conducted to determine if individual components of 32% UAN as well as ammonium sulfate (AMS) would provide control similar to that of 32% UAN. The addition of ammonium chloride, calcium nitrate, and ammonium sulfate at selected rates provided barnyardgrass control similar to that of 32% UAN.

No description available.