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11	Using Two-Dimensional Terahertz Spectroscopy to Explore Vibrations, Magnetism, and Their Coupling Biggs, Megan Faux 19 December 2024 (has links) (PDF) Terahertz (THz) light is at the resonant frequency of important fundamental excitations within crystalline materials such as carrier dynamics, phonons, and spin-wave excitations called magnons. THz light can be produced at high field strengths using optical rectification in nonlinear optical (NLO) crystals. N-benzyl-2-methyl-4-nitroaniline (BNA) is one such crystal commonly used to produce THz when pumping with 800 nm light. Here, we improve upon the design of the molecular building blocks of BNA by replacing a hydrogen atom with a fluorine atom, leading to improved THz generation and a higher crystal damage threshold. Later, we focus on using THz light to strongly drive nonlinear processes within a variety of materials to begin to unpack energy transfer pathways. Two-dimensional (2D) THz spectroscopy is a crucial tool in beginning to unpack these complicated dynamics for future use in technological advancements such as ultrafast switching. In the centrosymmetric crystal cadmium tungstate (CdWO4), we identify two sets of trilinear couplings between vibrational modes. Although the vibrational mode frequencies within these couplings appear inefficient, we show that the THz pulse itself lends bandwidth to the atomic motions to make the coupling possible. We push the limit of vibrational coupling identification in the complicated crystal β-barium borate (BBO) by combining a series of experimental techniques to limit the possible causes of our nonlinear signals from 521 couplings to 16. Later, we explore how THz light interacts with the lowest E(TO1) phonon-polariton in lithium niobate (LiNbO3) and show that a single THz pulse can excite various regions on the dispersion curve simultaneously, while a Raman-excitation can only excite a relatively narrow range of wavevectors. By exciting the phonon-polariton E mode using perpendicular THz pulses with a delay between them, we can drive the ions in LiNbO3 to move in a circular motion, which generates a magnetic field in this material with no innate magnetic ordering. Finally, we use 2D THz spectroscopy on bismuth ferrite (BFO), an antiferromagnetic material with both magnons and phonons within our THz frequency range. We identify nonlinear signals due to the coupling between phonons and phonons, magnons and phonons, and magnons and magnons. Terahertz terahertz generation BNA optical rectification ultrafast vibrational motion phonon anharmonic coupling magnon 2D terahertz spectroscopy phonon-polariton CdWO4 LiNbO3 BBO BiFeO3 Physical Sciences and Mathematics
12	A review of the impact of Canadian law, policy and P3 practice on the case for procuring capital-intensive infrastructure services via P3s Jatto, Lucky Bryce Junior 02 September 2011 (has links) This dissertation investigates the advantages of procuring capital-intensive infrastructure services via Public-Private Partnerships (P3s or PPPs) – cost and time savings and; innovation and high levels of efficiency – accounting for these advantages by reference to the underlying legal provisions and principles that facilitate them; and in this process highlights two significant directions in which Canadian P3 law, policy and practice has evolved – the enactment of P3 legislation and/or the formulation of non-statutory P3-related policy; as well as the establishment of legal institutions that promote and/or facilitate P3 procurements. The dissertation also addresses key arguments raised against P3s, by reference to aspects of Canadian law, policy and P3 practice. The research methodology comprises a detailed review of legal and non-legal sources. The implication of the research findings is that, given the foregoing developments in Canadian P3 law, policy and practice, the key arguments canvassed against P3s are overstated and lacking in merit. P3s PPPs P3 PPP PFI AFP PFIs AFPs infrastructure procurement investment private public public-private private-public policy law units conventional contract legislation statute case partnerships BOT BOO BOOT DBFM DBFO Operate finance project BF DBM DBOM partnership DBFOM concession concessions JVA JVAs O&M/M O&M BBO DB BT VfM risk penalties public-private partnerships
13	A review of the impact of Canadian law, policy and P3 practice on the case for procuring capital-intensive infrastructure services via P3s Jatto, Lucky Bryce Jr 02 September 2011 (has links) This dissertation investigates the advantages of procuring capital-intensive infrastructure services via Public-Private Partnerships (P3s or PPPs) – cost and time savings and; innovation and high levels of efficiency – accounting for these advantages by reference to the underlying legal provisions and principles that facilitate them; and in this process highlights two significant directions in which Canadian P3 law, policy and practice has evolved – the enactment of P3 legislation and/or the formulation of non-statutory P3-related policy; as well as the establishment of legal institutions that promote and/or facilitate P3 procurements. The dissertation also addresses key arguments raised against P3s, by reference to aspects of Canadian law, policy and P3 practice. The research methodology comprises a detailed review of legal and non-legal sources. The implication of the research findings is that, given the foregoing developments in Canadian P3 law, policy and practice, the key arguments canvassed against P3s are overstated and lacking in merit. P3s PPPs P3 PPP PFI AFP PFIs AFPs infrastructure procurement investment private public public-private private-public policy law units conventional contract legislation statute case partnerships BOT BOO BOOT DBFM DBFO Operate finance project BF DBM DBOM partnership DBFOM concession concessions JVA JVAs O&M/M O&M BBO DB BT VfM risk penalties public-private partnerships

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