The detection of trace amounts of H and D present in Zr-2.5%Nb in the form of ZrH and ZrD, respectively, by LIBS was explored. The intended use case for this experimentation was CANada Deuterium Uranium (CANDU) nuclear reactor pressure tube inspections where hydride buildup can lessen the mechanical strength of these components. As these tubes carry coolant and house the fuel bundles, their integrity is paramount. A LIBS inspection method is of interest in the nuclear industry due to the operational flexibility it would introduce and its ability to reduce the cost, time, and radiation dose associated with inspection campaigns of pressure tubes in CANDU nuclear reactors. Using LIBS, simultaneous detection of H and D was achieved in a low-pressure air environment using a microjoule, picosecond pulsed laser and emission being captured by a high-resolution spectrometer. The emission lines of the two species were blended, however, two peaks can be seen. Experiments using a milijoule, nanosecond pulsed laser in a LIBS setup were also conducted at atmospheric pressures. These experiments failed to show D emission, however. In addition to detecting emission from H and D, a Monte Carlo algorithm was developed for estimating the error associated with a LIBS inspection of a pressure tube segment. ZrH and ZrD form heterogeneous structures in the bulk of the Zr-2.5%Nb pressure tube material, meaning that a single measurement would not be indicative of the entire tube. Using metallographs of artificially hydrided pressure tube samples, the error within a given confidence interval was found as a function of number of measurement sites and ablation diameter. Furthermore, the impacts to Zr-2.5%Nb based on intense laser-matter interactions was investigated by optical microscopy and interferometry, allowing for 3-dimensional reconstructions of ablation craters. The morphology of millijoule, nanosecond pulsed laser-matter interaction and microjoule, picosecond pulsed laser-matter interaction were the subjects of this investigation. The salient difference between the two interactions is the evidence of substantial melting and subsequent re-deposition of material in the case of nanosecond interactions, whereas picosecond ablation yielded little melting. These results support the further development of a LIBS-based inspection method for determining the concentration of H and D in Zr-2.5%Nb. It was found that a vacuum environment allows for the simultaneous detection of H and D emission. Further experimentation should explore using low-pressure buffer gas environments as a method to further distinguish emission between the two species. / Thesis / Master of Applied Science (MASc)

Studying dynamics of proteins in their biological milieu such as water is interesting because of their strong absorption in the terahertz range that contain information on their global and sub-global collective vibrational modes (conformational dynamics) and global dynamical correlations among solvent water molecules and proteins. In addition, water molecules dynamics within protein solvation layers play a major role in enzyme activity. However, due to the strong absorption of water in the gigahertz-to-terahertz frequencies, it is challenging to study the properties of the solvent dynamics as well as the conformational changes of protein in water. In response, we have developed a highly sensitive megahertz-to-terahertz dielectric spectroscopy system to probe the hydration shells as well as large-scale dynamics of these biomolecules. Thereby, we have deduced the conformation flexibility of proteins and compare the hydration dynamics around proteins to understand the effects of surface-mediated solvent dynamics, relationships among different measures of interfacial solvent dynamics, and protein-mediated solvent dynamics based on the complex dielectric response from 50 MHz up to 2 THz by using the system we developed. Comparing these assets of various proteins in different classes helps us shed light on the macromolecular dynamics in a biologically relevant water environment. / Doctor of Philosophy / Proteins are complicated biomolecules that exist in all living creatures and they are, mostly, involved in building up structures and cell functions in various biological systems. Not only their existence but also their complex movements and dynamics are vital to cell functions in living beings. Until recently, their chemical functions and dynamics have been extremely challenging to investigate and track in their native environments. Thanks to various efforts by researchers all over the world to learn more about their convoluted behavior, new techniques have arisen to study these properties. We, as a part of this community, have been able to develop highly sensitive megahertz-to-terahertz dielectric spectroscopy system to probe proteins and other biomolecules dynamics in picosecond to microsecond range. Using our benchmark system, we have been able to map the detailed dynamical properties of biomolecules as well as their exclusive hydration shell characterizations. In this work, we gathered details about three well-known proteins and biomolecules by studying their dielectric responses. Thus, we have been able to discuss the movements, relaxation processes and hydration shell properties of these molecules in liquid water as their basic native environment.

The range of plasma spectroscopy tends to increase with the introduction of more efficient plasma excitation sources. In this thesis the use of one such plasma excitation source, the microwave induced plasma is evaluated as an atom cell for atomic spectrometry. The modes of spectrometry evaluated are atomic emission and atomic fluoresence. Analytical merits of the microwave induced plasma using detection limits and studies of interelement effects (i.e. vaporization, ionizationâ and scatter interferences) are also presented. / Master of Science

Yes / Measurement of molecular weight is an integral part of macromolecular and polymer characterization which usually has limitations. Herein, we present the use of a bench-top 80 MHz NMR spectrometer for diffusion-ordered spectroscopy as a practical and rapid approach for the determination of molecular weight/size using a novel solvent and polymer-independent universal calibration. / Royal Society. Grant Number: URF∖R1∖180274. Engineering and Physical Sciences Research Council. Grant Numbers: EP/V037943/1, EP/V007688/1, EP/V036211/1

Raman spectroscopy is an extremely versatile technique with molecular sensitivity and fingerprint specificity. However, the translation of this tool into a deployable technology has been stymied by irreproducibility in sample preparation and the lack of complex data analysis tools. In this dissertation, a droplet microfluidic platform was prototyped to address both sample-to-sample variation and to introduce a level of quantitation to surface enhanced Raman spectroscopy (SERS). Shifting the SERS workflow from a cell-to-cell mapping routine to the mapping of tens to hundreds of cells demanded the development of an automated processing tool to perform basic SERS analyses such as baseline correction, peak feature selection, and SERS map generation. The analysis tool was subsequently expanded for use with a multitude of diverse SERS applications. Specifically, a two-dimensional SERS assay for the detection of sialic acid residues on the cell membrane was translated into a live cell assay by utilizing a droplet microfluidic device. Combining single-cell encapsulation with a chamber array to hold and immobilize droplets allowed for the interrogation of hundreds of droplets. Our novel application of computer vision algorithms to SERS maps revealed that sialic sugars on cancer cell membranes are found in small clusters, or islands, and that these islands typically occupy less than 30% of the cell surface area. Employing an opportunistic mindset for the application of the data processing platform, a number of smaller projects were pursued. Biodegradable aliphatic-aromatic copolyesters with varying aromatic content were characterized using Raman spectroscopy and principal component analysis (PCA). The six different samples could successfully be distinguished from one another and the tool was able to identify spectral feature changes resulting from an increasing number of aryl esters. Uniquely, PCA was performed on the 3,125 spectra collected from each sample to investigate point-to-point heterogeneities. A third set of projects evaluated the ability of the data processing tool to calculate spectral ratios in an automated fashion and were exploited for use with nano-pH probes and Rayleigh hot-spot normalization. / Ph. D. / How can we understand the dynamic behavior of the cell membrane? Do certain polymeric structures in biodegradable plastic favor bacterial growth and subsequent degradation? To answer these and other intriguing scientific questions, techniques and technologies must be borrowed from a diverse array of fields and combined with fundamental understanding to create innovative solutions. In this dissertation, a two-dimensional surface enhanced Raman spectroscopy (SERS) assay was translated into a live cell assay by utilizing a droplet microfluidic device. Combining single-cell encapsulation with a chamber array to hold and immobilize droplets allowed for the interrogation of hundreds of droplets. Shifting the SERS workflow from a manual cell-to-cell mapping routine to the mapping of tens to hundreds of cells demanded the development of an automated processing tool to perform basic SERS analyses such as baseline correction, peak feature selection, and SERS map generation. Our novel application of computer vision algorithms to SERS maps was able to reveal that sialic sugars on cancer cell membranes are found in small clusters, or islands, and that these islands typically occupy less than 30% of the cell surface area. With an opportunistic mindset, several smaller projects that combine Raman and SERS with extensive data analysis were also pursued. Biodegradable plastics of varying content were studied with Raman spectroscopy. The aliphatic and aromatic polymeric units within these plastics both contain esters, but it is hypothesized that enzymatic hydrolysis occurs at the units asymmetrically. For each of six different samples, five maps were collected, processed using the analysis tool, and then analyzed using a multivariate analysis toolbox. Principal component analysis (PCA) was used to distinguish the polymers and to identify spectral feature changes resulting from an increasing v number of aryl esters. Uniquely, PCA was performed on the 3,125 spectra collected from each sample to investigate point-to-point heterogeneities. A third set of projects evaluated the ability of the data processing tool to calculate spectral ratios in an automated fashion and it was exploited for use with nano-pH probes and Rayleigh hot-spot normalization

Call number: LD2668 .T4 1943 W3 / Master of Science

Call number: LD2668 .T4 1963 F69 / Master of Science

Call number: LD2668 .T4 1965 M32 / Master of Science

Pure rotational spectra of simple metal carbon clusters that relevant to transition metal synthesis and catalysis have been obtained using Fourier transform microwave (FTMW) techniques combined with millimeter-wave direct-absorption methods. Rotational spectra of metal acetylides (CuCCH, ZnCCH, Li/Na/KCCH, MgCCH, AlCCH, CrCCH), diatomic metal monocarbide (CrC) and T-shape metal dicarbides (YC₂ and ScC₂) were recorded in the 4–650 GHz frequency regime. Measurements of weaker isotoplogues including ⁶⁶ZnCCH, ⁶⁸ZnCCH, Zn¹³C¹³CH, ZnCCD, Li/Na/KCCD, CrCCD, Y¹³C¹²C, Y¹³C¹³C, Sc¹³C¹³C, were also studied to aid in structural determinations. This work is the first study of ZnCCH and ScC₂ by any type of spectroscopic technique. Hyperfine splittings in MgCCH and Li/Na/KCCH have also been resolved and the weak isotoplogues of YC₂ have been measured for the first time. Potential interstellar molecules ScO and FeCN were studied using the FTMW techniques in the 4–62 GHz frequency regime. Spectra of the zinc insertion product ClZnCH₃ were additionally recorded in the 10–30 GHz (FTMW) and 260–296 GHz (direct absorption) frequency ranges, along with weaker isotopologues Cl⁶⁶ZnCH₃ and Cl⁶⁸ZnCH₃. This works is the first measurement of zinc insertion products using the FTMW-DALAS techniques. The data were analyzed implementing an effective Hamiltonian, allowing for accurate spectroscopic parameters to be established. From rotational constants, the molecular geometries were accurately determined. Electronic properties were also assessed, including the degree of covalent vs ionic character in a chemical bond, and the molecular orbital composition. The fundamental physical and chemical properties of these benchmark species were obtained in order to gain insight into their role in larger molecular systems, test theoretical calculations, and, in certain cases, provide accurate rest frequencies for astronomical searches.

Spectroscopic investigations have been carried out on hollow cathode discharges adapted from laser technology for use as a spectroscopic light source and the argon inductively coupled plasma (ICP) as an excitation source for nonmetal emission. High and low voltage aluminum and copper hollow cathode discharges were studied as a source of ionic and resonant atomic metal emission. The high voltage versions achieve strongly positive current-voltage behavior through utilization of the obstructed discharge phenomenon. The current-pressure-intensity-voltage relationships for low and high voltage copper hollow cathode discharges were studied with the inert gases He, Ne, Ar, Kr, and Xe. The intensity for copper resonant atomic emission with the fill gases Ar, Kr, and Xe improved relative to neon in the high voltage lamp when compared to the low voltage lamp. Absorption measurements through the cathode bore show the ground state atom density to increase with the atomic weight of the fill gas at any given level of intensity, at the fill gas pressure yielding highest resonant atomic copper emission. The estimated ion/atom intensity ratio is increased with fill gases which have metastable or ionization energies greater than the excitation energy of the ion transition. A copper hollow cathode lamp incorporating a short positive column discharge in front of the cathode opening was investigated for its lineshape as measured spectroscopically and by its atomic absorption sensitivity. Incorporation of this positive column allowed higher intensities to be obtained at the same line quality as a commercial hollow cathode lamp. An enlarged cathode volume also improves the lineshape at a given intensity. Inductively coupled plasma spectra for the elements C, O, N, Cl, P, S, and Br were obtained in the vacuum ultraviolet utilizing a vacuum polychromator and SWR film. The detection limit for injected O₂ and N₂ detected electronically by the VUV emissions is 1.3 and 0.9 micrograms respectively with this system. A VUV filter photometer was utilized for oxygen and phosphorus analysis. The detection limit for injected oxygen was 1 microgram with this photometer; the detection limit for phosphorus as inorganic phosphate in aqueous solution is 10⁻³ M. The bandpass of the photometer limits its selectivity.