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Dissertations / Theses on the topic 'Chemical structure'

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Published: 4 June 2021
Last updated: 29 July 2024

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1

Thakur, Smita. "A viewer for chemical structure /." Leeds, 2001. http://www.leeds.ac.uk/library/counter2/compstmsc/20002001/thakur.doc.

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2

Walsh, Catherine. "The chemical structure of protoplanetary disks." Thesis, Queen's University Belfast, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.534583.

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3

Lyndin, M. "Chemical structure of breast cancer concrements." Thesis, Sumy State University, 2015. http://essuir.sumdu.edu.ua/handle/123456789/40562.

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The process of pathological biomineralization plays an important role in tumor growth morphogenesis. The role of heavy metal salts in pathological mineralization of breast cancer tissue should not be ruled out taking into consideration their ability to enter in covalent bonds with calcium salt molecules.
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4

Iida, Kenji. "Systematic understanding of chemical process in solution." 京都大学 (Kyoto University), 2012. http://hdl.handle.net/2433/157607.

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5

Didsbury, Matthew Paul. "The influence of chemical structure of model epoxy networks on chemical resistance." Thesis, Durham University, 2014. http://etheses.dur.ac.uk/11009/.

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Structural differences in cross-linked epoxy networks from the use of different isomers (ortho-, meta- and para-) of disubstituted aromatic diglycidyl ethers can have a dramatic effect on the polymer properties. By changing the disubstitution from meta- to para- it has been shown that there is a direct correlation between the diffusion of gasses and the symmetry of related polymers. The aim of this work is to investigate the influence of the chemical structure of aromatic diglycidyl ethers on the ability of the resulting amine-cured epoxy polymer networks to adsorb organic solvents. Pure diglycidyl ethers based on hydroquinone and catechol, have been synthesised in high purity and good yields using a process previously developed at Durham University which utilise elemental fluorine to produce hypofluorous acid. The diglycidyl ether of resorcinol is commercially available and readily purified via vacuum distillation. Using the pure epoxides model networks have been produced by reacting the diglycidyl ethers with the diamine 4,4’-methylenebis(cyclohexylamine) to produce highly cross-linked films. Analytical techniques including DSC, DMTA, TGA, FTIR, solid state NMR, thermodynamic testing, PALs and density measurements have been used to investigate the influence of polymer structure on the network properties. With these materials we are determining the effect of the different epoxide isomers on the chemical resistance of the polymers. The results obtained for the polymers shows consistency with those suggested by the literature which is that the meta- polymer has the best chemical resistance with the other isomers having similar results.
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6

Jing, Pu. "Purple corn anthocyanins chemical structure, chemoprotective activity and structure/function relationships /." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1155738398.

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7

Jing, Pu. "Purple corn anthocyanins: chemical structure, chemoprotective sctivity and structure/function relationships." The Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=osu1155738398.

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8

Moscicki, Angelique (Angelique E. ). "ChemWARD : extracting chemical structure from printed diagrams." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/61299.

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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 117-118).
Over the years, a vast amount of literature in the field of chemistry has accumulated, and searching for documents about specific molecules is a formidable task. To the extent that the literature is textual, services like Google enable relatively easy search. While search indexes like Google are very good at finding such things, its difficult to describe molecules completely using text because text can't easily indicate molecular structure, and molecular structure defines chemical properties. ChemWARD is a system that extracts the molecular structure from the printed diagrams that are ubiquitous in chemistry literature and converts them to a machine readable format in order to allow chemists to search the literature by drawing a molecular structure instead of typing a chemical formula. We describe the architecture of the system and report on its performance, demonstrating its ability to achieve an overall accuracy rate of 85.5% on printed diagrams extracted from published chemical literature.
by Angelique Moscicki.
M.Eng.
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9

Robustelli, Paul. "Protein structure determination from NMR chemical shifts." Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609027.

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10

Abildgaard, Jens. "Quantum chemical models in molecular structure elucidation /." Roskilde : Roskilde University, Department of Life Sciences and Chemistry, 1998. http://hdl.handle.net/1800/535.

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11

Gabriel, Christopher. "Effect of localized structural perturbations on dendrimer structure." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1155662110.

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12

Butler, J. "Coal structure." Thesis, University of Newcastle Upon Tyne, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378290.

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13

Henriksson, Marielle. "Cellulose nanocomosite films : processing, structure and properties." Licentiate thesis, KTH, Aeronautical and Vehicle Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-350.

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14

ua, holovko@icmp lviv. "Chemical association and electronic structure: A new theoretical." Journal, 1997. http://www.fluid.iqfr.csic.es/papers/chem_aso/chem_aso.html.

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15

Drynan, James Warren. "Elucidating the chemical structure of black tea thearubigins." Thesis, University of Surrey, 2009. http://epubs.surrey.ac.uk/843537/.

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A solid-phase synthesis protocol was developed, that enabled phenol-protected (-)-epicatechin, and (-)-epigallocatechin to be selectively linked to functionalised resins, as a method to investigate the mechanism of catechin oxidation, which during black tea manufacturing, leads to the ubiquitous and partially characterised thearubigins. Solid-phase synthesis was chosen because model oxidation of catechins can be undertaken, without the solution-phase disadvantage of producing undefined intermediates, and products, which are difficult to isolate. Although (-)-epigallocatechin has a lower redox potential than (-)-epicatechin, and is therefore required to be linked to the resin during oxidation to prevent uncontrolled oxidation-reduction dismutation, or oligomerisation, (-)-epicatechin was used as the model catechin to develop aspects of the synthetic protocol. The four phenol groups in (-)-epicatechin were selectively protected with the allyl protecting group. Phenol-protected (-)-epicatechin was then selectively linked, via the secondary, aliphatic 3-OH position, via a symmetrical diisopropylsilyl linker, to hydroxytentagel resin. The selective linkage was relatively high yielding (84.6%); however, solid-phase synthesis requires yields greater than 97%, rendering the protocol uneconomical. The five phenol groups in (-)-epigallocatechin were selectively protected with the allyl protecting group. Phenol-protected (-)-epigallocatechin was selectively linked, via the aliphatic, secondary 3-OH position, via a symmetrical diisopropylsilyl linker, a 1,4-disubstituted 1,2,3-triazole, and an amide bond, to aminotentagel resin in high yield (> 97%). The five allyl protecting groups were selectively removed with a palladium(0) catalyst. Subsequent chemical oxidation, with potassium hexacyanoferrate(III) and co-substrate (-)-epicatechin, led to one major, resin-linked product. The product was selectively cleaved from the resin by fluoride, and preliminary FT-IR, NMR and MS data were acquired. By substituting aminotentagel resin with PEGA resin, the synthetic protocol developed (linkage of (-)-epigallocatechin to a resin), can be used for the biomimetical oxidation of resin-linked catechins, using polyphenol oxidase and/or peroxidase.
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16

Li, Weiyao. "Chemical structure and optical functions of synthetic melanin." University of Akron / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=akron1627042724510547.

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17

Gallagher, Oliver Paul. "Structure and synthesis in natural product chemistry /." [St. Lucia, Qld. : s.n.], 2002. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16653.pdf.

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18

Chanamé, Domínguez Julio César. "Topics of galactic structure and stellar and chemical evolution." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1126128106.

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Thesis (Ph. D.)--Ohio State University, 2005.
Title from first page of PDF file. Document formatted into pages; contains xv, 286 p.; also includes graphics (some col.). Includes bibliographical references (p. 275-286). Available online via OhioLINK's ETD Center
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19

Mallon, James M. "Floc structure and the improvement of chemical water cleaning." Thesis, Queen's University Belfast, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324839.

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20

Oakley, Angela L. "Typesetting of integrated scientific text and chemical structure diagrams." Thesis, University of Portsmouth, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.237873.

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21

Siddiqui, Mohammad Nahid. "Studies on structure and chemical composition of Arabian asphalt." Thesis, Heriot-Watt University, 1997. http://hdl.handle.net/10399/671.

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22

Zou, Tingting. "Chemical Biology Approaches for Investigating Nucleosome Structure and Accessibility." Kyoto University, 2018. http://hdl.handle.net/2433/232271.

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23

Chaname, Julio. "Topics of galactic structure and stellar and chemical evolution." The Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1126128106.

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24

Kim, Yang-Soo. "Electronic Structure and Chemical Bonding of Transition Metal Dichalcogenides." Kyoto University, 1999. http://hdl.handle.net/2433/181809.

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25

Haworth, Naomi Louise. "Quantum Chemical Studies of Thermochemistry, Kinetics and Molecular Structure." Thesis, The University of Sydney, 2003. http://hdl.handle.net/2123/509.

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This thesis is concerned with a range of chemical problems which are amenable to theoretical investigation via the application of current methods of computational quantum chemistry. These problems include the calculation of accurate thermochemical data, the prediction of reaction kinetics, the study of molecular potential energy surfaces, and the investigation of molecular structures and binding. The heats of formation (from both atomisation energies and isodesmic schemes) of a set of approximately 120 C1 and C2 fluorocarbons and oxidised fluorocarbons (along with C3F6 and CF3CHFCF2) were calculated with the Gaussian-3 (G3) method (along with several approximations thereto). These molecules are of importance in the flame chemistry of 2-H-heptafluoropropane, which has been proposed as a potential fire retardant with which to replace chloro- and bromofluorocarbons (CFC�s and BFC�s). The calculation of the data reported here was carried out in parallel with the modelling studies of Hynes et al.1-3 of shock tube experiments on CF3CHFCF3 and on C3F6 with either hydrogen or oxygen atoms. G3 calculations were also employed in conjunction with the experimental work of Owens et al.4 to describe the pyrolysis of CFClBr2 (giving CFCl) at a radiation wavelength of 265 nm. The theoretical prediction of the dissociation energy of the two C-Br bonds was found to be consistent with the energy at which carbene production was first observed, thus supporting the hypothesis that the pyrolysis releases two bromine radicals (rather than a Br2 molecule). On the basis of this interpretation of the experiments, the heat of formation of CFClBr2 is predicted to be 184 � 5 kJ mol-1, in good agreement with the G3 value of 188 � 5 kJ mol-1. Accurate thermochemical data was computed for 18 small phosphorus containing molecules (P2, P4, PH, PH2, PH3, P2H2, P2H4, PO, PO2, PO3, P2O, P2O2, HPO, HPOH, H2POH, H3PO, HOPO and HOPO2), most of which are important in the reaction model introduced by Twarowski5 for the combustion of H2 and O2 in the presence of phosphine. Twarowski reported that the H + OH recombination reaction is catalysed by the combustion products of PH3 and proposed two catalytic cycles, involving PO2, HOPO and HOPO2, to explain this observation. Using our thermochemical data we computed the rate coefficients of the most important reactions in these cycles (using transition state and RRKM theories) and confirmed that at 2000K both cycles have comparable rates and are significantly faster than the uncatalysed H + OH recombination. The heats of formation used in this work on phosphorus compounds were calculated using the G2, G3, G3X and G3X2 methods along with the far more extensive CCSD(T)/CBS type scheme. The latter is based on the evaluation of coupled cluster energies using the correlation consistent triple-, quadruple- and pentuple-zeta basis sets and extrapolation to the complete basis set (CBS) limit along with core-valence correlation corrections (with counterpoise corrections for phosphorus atoms), scalar relativistic corrections and spin-orbit coupling effects. The CCSD(T)/CBS results are consistent with the available experimental data and therefore constitute a convenient set of benchmark values with which to compare the more approximate Gaussian-n results. The G2 and G3 methods were found to be of comparable accuracy, however both schemes consistently underestimated the benchmark atomisation energies. The performance of G3X is significantly better, having a mean absolute deviation (MAD) from the CBS results of 1.8 kcal mol-1, although the predicted atomisation energies are still consistently too low. G3X2 (including counterpoise corrections to the core-valence correlation energy for phosphorus) was found to give a slight improvement over G3X, resulting in a MAD of 1.5 kcal mol-1. Several molecules were also identified for which the approximations underlying the Gaussian-n methodologies appear to be unreliable; these include molecules with multiple or strained P-P bonds. The potential energy surface of the NNH + O system was investigated using density functional theory (B3LYP/6-31G(2df,p)) with the aim of determining the importance of this route in the production of NO in combustion reactions. In addition to the standard reaction channels, namely decomposition into NO + NH, N2 + OH and H + N2O via the ONNH intermediate, several new reaction pathways were also investigated. These include the direct abstraction of H by O and three product channels via the intermediate ONHN, giving N2 + OH, H + N2O and HNO + N. For each of the species corresponding to stationary points on the B3LYP surface, valence correlated CCSD(T) calculations were performed with the aug-cc-pVxZ (x = Q, 5) basis sets and the results extrapolated to the complete basis set limit. Core-valence correlation corrections, scalar relativistic corrections and spin orbit effects were also included in the resulting energetics and the subsequent calculation of thermochemical data. Heats of formation were also calculated using the G3X method. Variational transition state theory was used to determine the critical points for the barrierless reactions and the resulting B3LYP energetics were scaled to be compatible with the G3X and CCSD(T)/CBS values. As the results of modelling studies are critically dependent on the heat of formation of NNH, more extensive CCSD(T)/CBS calculations were performed for this molecule, predicting the heat of formation to be 60.6 � 0.5 kcal mol-1. Rate coefficients for the overall reaction processes were obtained by the application of multi-well RRKM theory. The thermochemical and kinetic results thus obtained were subsequently used in conjunction with the GRIMech 3.0 reaction data set in modelling studies of combustion systems, including methane / air and CO / H2 / air mixtures in completely stirred reactors. This study revealed that, contrary to common belief, the NNH + O channel is a relatively minor route for the production of NO. The structure of the inhibitor Nd-(N'-Sulfodiaminophosphinyl)-L-ornithine, PSOrn, and the nature of its binding to the OTCase enzyme was investigated using density functional (B3LYP) theory. The B3LYP/6-31G(d) calculations on the model compound, PSO, revealed that, while this molecule could be expected to exist in an amino form in the gas phase, on complexation in the active site of the enzyme it would be expected to lose two protons to form a dinegative imino tautomer. This species is shown to bind strongly to two H3CNHC(NH2)2+ moieties (model compounds for arginine residues), indicating that the strong binding observed between inhibitor and enzyme is partially due to electrostatic interactions as well as extensive hydrogen bonding (both model Arg+ residues form hydrogen bonds to two different sites on PSO). Population analysis and hydrogen bonding studies have revealed that the intramolecular bonding in this species consists of either single or semipolar bonds (that is, S and P are not hypervalent) and that terminal oxygens (which, being involved in semipolar bonds, carry negative charges) can be expected to form up to 4 hydrogen bonds with residues in the active site. In the course of this work several new G3 type methods were proposed, including G3MP4(SDQ) and G3[MP2(Full)], which are less expensive approximations to G3, and G3X2, which is an extension of G3X designed to incorporate additional electron correlation. As noted earlier, G3X2 shows a small improvement on G3X; G3MP4(SDQ) and G3[MP2(Full)], in turn, show good agreement with G3 results, with MAD�s of ~ 0.4 and ~ 0.5 kcal mol-1 respectively. 1. R. G. Hynes, J. C. Mackie and A. R. Masri, J. Phys. Chem. A, 1999, 103, 5967. 2. R. G. Hynes, J. C. Mackie and A. R. Masri, J. Phys. Chem. A, 1999, 103, 54. 3. R. G. Hynes, J. C. Mackie and A. R. Masri, Proc. Combust. Inst., 2000, 28, 1557. 4. N. L. Owens, Honours Thesis, School of Chemistry, University of Sydney, 2001. 5. A. Twarowski, Combustion and Flame, 1995, 102, 41.
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26

Haworth, Naomi Louise. "Quantum Chemical Studies of Thermochemistry, Kinetics and Molecular Structure." University of Sydney. Chemistry, 2003. http://hdl.handle.net/2123/509.

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This thesis is concerned with a range of chemical problems which are amenable to theoretical investigation via the application of current methods of computational quantum chemistry. These problems include the calculation of accurate thermochemical data, the prediction of reaction kinetics, the study of molecular potential energy surfaces, and the investigation of molecular structures and binding. The heats of formation (from both atomisation energies and isodesmic schemes) of a set of approximately 120 C1 and C2 fluorocarbons and oxidised fluorocarbons (along with C3F6 and CF3CHFCF2) were calculated with the Gaussian-3 (G3) method (along with several approximations thereto). These molecules are of importance in the flame chemistry of 2-H-heptafluoropropane, which has been proposed as a potential fire retardant with which to replace chloro- and bromofluorocarbons (CFC�s and BFC�s). The calculation of the data reported here was carried out in parallel with the modelling studies of Hynes et al.1-3 of shock tube experiments on CF3CHFCF3 and on C3F6 with either hydrogen or oxygen atoms. G3 calculations were also employed in conjunction with the experimental work of Owens et al.4 to describe the pyrolysis of CFClBr2 (giving CFCl) at a radiation wavelength of 265 nm. The theoretical prediction of the dissociation energy of the two C-Br bonds was found to be consistent with the energy at which carbene production was first observed, thus supporting the hypothesis that the pyrolysis releases two bromine radicals (rather than a Br2 molecule). On the basis of this interpretation of the experiments, the heat of formation of CFClBr2 is predicted to be 184 � 5 kJ mol-1, in good agreement with the G3 value of 188 � 5 kJ mol-1. Accurate thermochemical data was computed for 18 small phosphorus containing molecules (P2, P4, PH, PH2, PH3, P2H2, P2H4, PO, PO2, PO3, P2O, P2O2, HPO, HPOH, H2POH, H3PO, HOPO and HOPO2), most of which are important in the reaction model introduced by Twarowski5 for the combustion of H2 and O2 in the presence of phosphine. Twarowski reported that the H + OH recombination reaction is catalysed by the combustion products of PH3 and proposed two catalytic cycles, involving PO2, HOPO and HOPO2, to explain this observation. Using our thermochemical data we computed the rate coefficients of the most important reactions in these cycles (using transition state and RRKM theories) and confirmed that at 2000K both cycles have comparable rates and are significantly faster than the uncatalysed H + OH recombination. The heats of formation used in this work on phosphorus compounds were calculated using the G2, G3, G3X and G3X2 methods along with the far more extensive CCSD(T)/CBS type scheme. The latter is based on the evaluation of coupled cluster energies using the correlation consistent triple-, quadruple- and pentuple-zeta basis sets and extrapolation to the complete basis set (CBS) limit along with core-valence correlation corrections (with counterpoise corrections for phosphorus atoms), scalar relativistic corrections and spin-orbit coupling effects. The CCSD(T)/CBS results are consistent with the available experimental data and therefore constitute a convenient set of benchmark values with which to compare the more approximate Gaussian-n results. The G2 and G3 methods were found to be of comparable accuracy, however both schemes consistently underestimated the benchmark atomisation energies. The performance of G3X is significantly better, having a mean absolute deviation (MAD) from the CBS results of 1.8 kcal mol-1, although the predicted atomisation energies are still consistently too low. G3X2 (including counterpoise corrections to the core-valence correlation energy for phosphorus) was found to give a slight improvement over G3X, resulting in a MAD of 1.5 kcal mol-1. Several molecules were also identified for which the approximations underlying the Gaussian-n methodologies appear to be unreliable; these include molecules with multiple or strained P-P bonds. The potential energy surface of the NNH + O system was investigated using density functional theory (B3LYP/6-31G(2df,p)) with the aim of determining the importance of this route in the production of NO in combustion reactions. In addition to the standard reaction channels, namely decomposition into NO + NH, N2 + OH and H + N2O via the ONNH intermediate, several new reaction pathways were also investigated. These include the direct abstraction of H by O and three product channels via the intermediate ONHN, giving N2 + OH, H + N2O and HNO + N. For each of the species corresponding to stationary points on the B3LYP surface, valence correlated CCSD(T) calculations were performed with the aug-cc-pVxZ (x = Q, 5) basis sets and the results extrapolated to the complete basis set limit. Core-valence correlation corrections, scalar relativistic corrections and spin orbit effects were also included in the resulting energetics and the subsequent calculation of thermochemical data. Heats of formation were also calculated using the G3X method. Variational transition state theory was used to determine the critical points for the barrierless reactions and the resulting B3LYP energetics were scaled to be compatible with the G3X and CCSD(T)/CBS values. As the results of modelling studies are critically dependent on the heat of formation of NNH, more extensive CCSD(T)/CBS calculations were performed for this molecule, predicting the heat of formation to be 60.6 � 0.5 kcal mol-1. Rate coefficients for the overall reaction processes were obtained by the application of multi-well RRKM theory. The thermochemical and kinetic results thus obtained were subsequently used in conjunction with the GRIMech 3.0 reaction data set in modelling studies of combustion systems, including methane / air and CO / H2 / air mixtures in completely stirred reactors. This study revealed that, contrary to common belief, the NNH + O channel is a relatively minor route for the production of NO. The structure of the inhibitor Nd-(N'-Sulfodiaminophosphinyl)-L-ornithine, PSOrn, and the nature of its binding to the OTCase enzyme was investigated using density functional (B3LYP) theory. The B3LYP/6-31G(d) calculations on the model compound, PSO, revealed that, while this molecule could be expected to exist in an amino form in the gas phase, on complexation in the active site of the enzyme it would be expected to lose two protons to form a dinegative imino tautomer. This species is shown to bind strongly to two H3CNHC(NH2)2+ moieties (model compounds for arginine residues), indicating that the strong binding observed between inhibitor and enzyme is partially due to electrostatic interactions as well as extensive hydrogen bonding (both model Arg+ residues form hydrogen bonds to two different sites on PSO). Population analysis and hydrogen bonding studies have revealed that the intramolecular bonding in this species consists of either single or semipolar bonds (that is, S and P are not hypervalent) and that terminal oxygens (which, being involved in semipolar bonds, carry negative charges) can be expected to form up to 4 hydrogen bonds with residues in the active site. In the course of this work several new G3 type methods were proposed, including G3MP4(SDQ) and G3[MP2(Full)], which are less expensive approximations to G3, and G3X2, which is an extension of G3X designed to incorporate additional electron correlation. As noted earlier, G3X2 shows a small improvement on G3X; G3MP4(SDQ) and G3[MP2(Full)], in turn, show good agreement with G3 results, with MAD�s of ~ 0.4 and ~ 0.5 kcal mol-1 respectively. 1. R. G. Hynes, J. C. Mackie and A. R. Masri, J. Phys. Chem. A, 1999, 103, 5967. 2. R. G. Hynes, J. C. Mackie and A. R. Masri, J. Phys. Chem. A, 1999, 103, 54. 3. R. G. Hynes, J. C. Mackie and A. R. Masri, Proc. Combust. Inst., 2000, 28, 1557. 4. N. L. Owens, Honours Thesis, School of Chemistry, University of Sydney, 2001. 5. A. Twarowski, Combustion and Flame, 1995, 102, 41.
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27

Ronneteg, Sabina. "Chemical Tuning of the Magnetic Interactions in Layer Structures." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-5973.

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28

Jarvis, J. "Occupational allergy to low molecular weight organic chemicals : the role of structure in determining chemical hazard." Thesis, University of Edinburgh, 1999. http://hdl.handle.net/1842/28300.

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A number of low molecular weight (LMW) organic chemicals are known to cause occupational respiratory or skin sensitisation. A set of 200 LMW organic skin and 75 respiratory sensitisers was identified by systematic search and critical appraisal of published cases and epidemiologic literature. In addition a set of 302 control chemicals was selected from known hazardous LMW organic chemicals for which no reports of respiratory sensitisation could be found. Several approaches based on chemical structure and using a case-control methodology were investigated to differentiate between asthmagens and controls, or asthmagens and skin sensitisers (by chemical structure alone) were investigated. These comprised hazardous fragment identification by calculating odds ratios for hazard (HOR's), cluster analysis and logistic regression analysis. Of these methods the most effective approach was the logistic regression analysis. Using these methods several known or suspected hazardous substructures were confirmed to present statistically significant occupational asthma (OA) hazard. These included isocyanates, acid anhydrides, acrylates and (oligo)-amines. Many hazardous compounds contained pairs of hazardous substructures. Furthermore, certain sub-structural fragments such as chlorine atoms appeared to provide a protective effect from OA hazard. For differentiating between skin sensitizers and asthmagens it was noted that fragments with carbon double bonded to nitrogen or oxygen atoms were significantly more prevalent in the respiratory sensitisers set. A predictive model of chemical asthma hazard was created using logistic regression and the model tested on a validation set of chemicals yielded a predictive kappa value of 0.7. This model is available for predictive testing of compounds for asthma hazard via the World Wide Web. This work demonstrates that simple structural information may, in conjunction with a well designed methodology, be used to identify occupational sensitisers with reasonable reliability.
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29

Moosavian, Mohammad Ali. "The structure and stability of liquid foam." Thesis, University of Manchester, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332024.

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30

Razi, Javeed. "Investigation of the structure of coal using ultrasonic energy." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=28519.

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The aim of the research was to find out more about the structure of bituminous coal by studying the rate of mass transfer in coal particles. Previous investigations had shown that small molecules could be trapped in the coal matrix in two different ways. A procedure was developed to keep the various extracts separate from one another.
Each of the extracts were analyzed in the following ways: (a) Ultimate analysis; (b) Molecular weight determination; (c) FT-IR spectra; (d) Differential scanning calorimetry; and (e) Thermogravimetric analysis.
In the extraction process the first extraction was simple Soxhlet extraction. The residue from this was irradiated with ultrasonic energy and then re-extracted. The residue of the second extraction was ground to a small size and re-extracted without using ultrasonics. The fourth extraction was on the residue of the third extract, using ultrasonics.
In general the molecular weight of each successive extract increased while the amount of extract decreased. From the chemical analysis and the molecular weights it appears that the successive extracts are, by and large, members of a family of addition polymers. This finding, coupled with the fact that over 60% of the total coal could be extracted by the procedures used, shows that the bulk of this coal does not consist of a cross-linked polymer.
As was shown in previous research the rate of extraction using ultrasonic energy did not rupture and chemical bonds and the extraction rate curve approximated that predicted by Fick's Law, being slightly lower initially and slightly higher later. This work confirmed this. It can be concluded that the only effect of the ultrasonic irradiation was to speed up the relaxation of the glassy coal matrix and release the small molecules so that they could diffuse.
The diffusivities of the molecules being extracted was determined for different sized particles. The apparent diffusivity became smaller as the particle size became smaller. This is the opposite of what would be expected if the molecules were diffusing out of small pores.
To explain this anomalous effect it has been hypothesized that many of the coal molecules are trapped inside a molecular cage or clathrate, which has been formed from fossilized lignin of the original plants.
Some auxiliary experiments were carried out to ascertain the practicability of shattering the coal by soaking the coal particles in a liquid at high pressure and temperature and then suddenly releasing the pressure to let the liquid flash to vapor. The process worked well to produce small coal particles, but there were difficulties in recovering all the coal particles when pyridine was used as the liquid.
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31

Lutkenhaus, Jodie Lee. "Ion transport and structure of layer-by-layer assemblies." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/39346.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2007.
"June 2007."
Includes bibliographical references.
Layer-by-layer (LbL) films of various architectures were examined as potential solid state electrolytes for electrochemical systems (e.g. batteries and fuel cells). The relationship between materials properties and ion transport within LbL films was investigated in three systems, described below. The observed structure and properties aid in the design of tunable ultra thin electrolytes. The thermal and mechanical properties of PEO/PAA films were evaluated, aided by a new peel-away technique. Results indicated that the glass transition temperature (Tg) of PEO/PAA films decreases with increasing assembly pH, but when assembled in the presence of salt, the Tg, remains constant. Results indicate that the degree of inter- and intramolecular PAA hydrogen bonding, evidenced by FTIR spectroscopy, controls the observed Tg. The ionic conductivity was found to increase with increasing charge carrier concentration (doping during assembly) and with humidity. Maximum room temperature dry conductivity was -108 S cm-1. Polymer-clay nanocomposites were investigated for structural and transport anisotropy. LPEI/Laponite/PEO films demonstrated an oriented structure where clay nanoplatelets lay parallel to the substrate and assembly in sheets with polymer in-between.
(cont.) In-plane conductivity was 100 (or 7) times higher than cross-plane conductivity in the dry (or 53 % humidity) state. Porous coatings of LPEI and PAA were investigated as potential ultra thin porous supports for non-aqueous liquid electrolyte. The effect of assembly pH and post-assembly treatment ph upon the pore size, porosity, surface roughness and structure was study. Films assembled at ph 5 and treated at pH 2.25 demonstrated the highest porosity (77 %) and two room temperature, dry conductivities of 10-6 and 10-9 S cm-1. The two observed conductivities, or time constants, was attributed to ion transport through liquid-filled pores and the matrix itself.
by Jodie Lee Lutkenhaus.
Ph.D.
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32

Yanna, Alakananda. "Development of Strategies in Protein Crystallization for Structure Determination." University of Toledo / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1449080492.

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33

Pastorino, Andres J. "Effect of Chemical Parameters on Structure-Function Relationships of Cheese." DigitalCommons@USU, 2002. https://digitalcommons.usu.edu/etd/5498.

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The effect of chemical parameters on cheese structure and functionality was studied by modifying the calcium, salt content, and pH of cheese. Cheese blocks were high-pressure injected from zero to five times with water, solutions of different salts, or an acid solution 14 d after manufacture. Successive injections were performed 24 h apart. After 40-42 d of refrigerated storage, cheese structure was studied by using scanning electron microscopy and digital image analysis, and cheese functionality was characterized by texture profile analysis and melting test. Increased salt content of cheese (2.7 versus 0.1%) caused the protein matrix to become more hydrated and to expand (P < 0.1 ), though the occurrence of syneresis resulted in decreased moisture content of cheese (P < 0.05). Salt injection increased cheese hardness and the initial rate of cheese flow, but it decreased cheese cohesiveness (P < 0.05). Increased calcium content (1.8 versus 0.3%) and decreased pH of cheese (4.7 versus 5.3) caused contraction of the protein matrix (P < 0.05) and release of serum. Thus, the matrix became less hydrated, and the moisture content and weight of cheese decreased (P < 0.05). Calcium injection decreased the pH and melting of cheese, but it increased cheese hardness (P < 0.05). Acid injection promoted calcium solubilization and decreased calcium content of cheese (P < 0.05). Above pH 5.0 (5.0-5.3), acid injection decreased cheese hardness and increased the initial rate of cheese flow (P < 0.05). Below pH 5.0 (5.0-4.7), acid injection decreased cheese cohesiveness, and the initial rate and extent of cheese flow (P < 0.05). In conclusion, modifying the chemical composition of cheese alters protein interactions, resulting in cheese with different structural and functional properties. Increased salt content of cheese (up to 2.7%) impairs protein-to-protein interactions, and its effect is most significant when salt content increases from 0 to 0.5%. Below 5.0 (5.0- 4.7), the effect of pH predominates over calcium content, and decreased cheese pH promotes protein-to-protein interactions. Increased calcium content of cheese (up to 1.8%) also promotes protein-to-protein interactions, and the content of protein-bound calcium may be the major factor controlling the functionality of most cheeses.
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34

Nohako, Kanyisa L. "Organic clathrates : structure and reactivity." Thesis, Cape Peninsula University of Technology, 2009. http://hdl.handle.net/20.500.11838/740.

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Thesis (MTech (Chemistry))--Cape Peninsula University of Technology, 2009
The host compound 9-(4-methoxyphenyl)-9H-xanthen-9-01 (AI) forms inclusion compounds with the solid guests l -naphthylamine (NAPH), 8-hydroxyquinoline (HQ). acridine (ACRI), 1,4 - diazabicyclo[2.2.2]octane (DABCO) and a liquid guest benzaldehyde (BENZAL). All four structures AI·YzNAPH, AI· Y,HQ AI·ACRI and AI ·Y,DABCO were successfully solved in the triclinic space group P I . The structure of AI·Y,BENZAL was successfully solved in the monocl inic space group P2dn . Similar packin g motifs arise for the NAPH and HQ inclusion compounds where the main interaction is of the fonm (Host)-OH····O-(Host). Both the DABCO and the ACRI guests hydrogen bond to the host molecule. The host: guest ratios for A I·ACRI. AI· Y,NAPH. A I· Y,DABCO and A I· YzHQ were found using nuclear magnetic resonance (NMR) spectroscopy. The host:guest ratio for AI·YzBENZAL was found using thenmogravimetric analysis. Enthalpy changes of the inclusion compounds were monitored using differential scanning calorimetry (DSC). Kinetics of desolvation for AI·Y,BENZAL were conducted using a non - isothenmal method where we have obtained an activation energy range of 74 k J morl - 86 k J mor' . The solid - solid reaction kinetics for A I·Y,NAPH, A I· Y,HQ, AI·ACRI and AI ·Y,DABCO were determined at room temperature using powder X-ray diffraction (PXRD).
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35

Fesinmeyer, Robert Matthew. "Chemical shifts define the structure and folding thermodynamics of polypeptides /." Thesis, Connect to this title online; UW restricted, 2005. http://hdl.handle.net/1773/11621.

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36

Andersson, Patrik. "Physico-chemical characteristics and quantitative structure-activity relationships of PCBs." Doctoral thesis, Umeå University, Chemistry, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-17.

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The polychlorinated biphenyls (PCBs) comprise a group of 209 congeners varying in the number of chlorine atoms and substitution patterns. These compounds tend to be biomagnified in foodwebs and have been shown to induce an array of effects in exposed organisms. The structural characteristics of the PCBs influence their potency as well as mechanism of action. In order to assess the biological potency of these compounds a multi-step quantitative structure-activity relationship (QSAR) procedure was used in the project described in this thesis.

The ultraviolet absorption (UV) spectra were measured for all 209 PCBs, and digitised for use as physico-chemical descriptors. Interpretations of the spectra using principal component analysis (PCA) showed the number of ortho chlorine atoms and para-para substitution patterns to be significant. Additional physico-chemical descriptors were derived from semi-empirical calculations. These included various molecular energies, the ionisation potential, electron affinity, dipole moments, and the internal barrier of rotation. The internal barrier of rotation was especially useful for describing the conformation of the PCBs on a continuous scale.

In total 52 physico-chemical descriptors were compiled and analysed by PCA for the tetra- to hepta-chlorinated congeners. The structural variation within these compounds was condensed into four principal properties derived from a PCA for use as design variables in a statistical design to select congeners representative for these homologue-groups. The 20 selected PCBs have been applied to study structure-specific biochemical responses in a number of bioassays, and to study the biomagnification of the PCBs in various fish species.

QSARs were established using partial least squares projections to latent structures (PLS) for the PCBs potency to inhibit intercellular communication, activate respiratory burst, inhibit dopamine uptake in synaptic vesicles, compete with estradiol for binding to estrogen receptors, and induce cytochrome P4501A (CYP1A) related activities. By the systematic use of the designed set of PCBs the biological potency was screened over the chemical domain of the class of compounds. Further, sub-regions of highly potent PCBs were identified for each response measured. For risk assessment of the PCBs potency to induce dioxin-like activities the predicted induction potencies (PIPs) were calculated. In addition, two sets of PCBs were presented that specifically represent congeners of environmental relevance in combination with predicted potency to induce estrogenic and CYP1A related activities.

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37

Moni, Bidin Christian. "Kinematical and Chemical Vertical Structure of the Galactic Thick Disk." Tesis, Universidad de Chile, 2009. http://www.repositorio.uchile.cl/handle/2250/102108.

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38

Jürgensen, Astrid. "Probing electronic structure and chemical bonding with x-ray spectroscopy." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0034/NQ46862.pdf.

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39

Crispin, Annica. "Chemical and electronic structure of interfaces in organic-based devices /." Linköping : Univ, 2002. http://www.bibl.liu.se/liupubl/disp/disp2002/tek781s.pdf.

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40

Wang, Hao. "Design of a Structure Search Engine for Chemical Compound Database." Digital Archive @ GSU, 2008. http://digitalarchive.gsu.edu/cs_diss/33.

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The search for structural fragments (substructures) of compounds is very important in medicinal chemistry, QSAR, spectroscopy, and many other fields. In the last decade, with the development of hardware and evolution of database technologies, more and more chemical compound database applications have been developed along with interfaces of searching for targets based on user input. Due to the algorithmic complexity of structure comparison, essentially a graph isomorphism problem, the current applications mainly work by the approximation of the comparison problem based on certain chemical perceptions and their search interfaces are often e-mail based. The procedure of approximation usually invokes subjective assumption. Therefore, the accuracy of the search is undermined, which may not be acceptable for researchers because in a time-consuming drug design, accuracy is always the first priority. In this dissertation, a design of a search engine for chemical compound database is presented.The design focuses on providing a solution to develop an accurate and fast search engine without sacrificing performance. The solution is comprehensive in a way that a series of related problems were addressed throughout the dissertation with proposed methods. Based on the design, a flexible computing model working for compound search engine can be established and the model can be easily applied to other applications as well. To verify the solution in a practical manner, an implementation based on the presented solution was developed. The implementation clarifies the coupling between theoretic design and technique development. In addition, a workable implementation can be deployed to test the efficiency and effectiveness of the design under variant of experimental data.
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41

Sadawi, Noureddin. "A rule-based approach for recognition of chemical structure diagrams." Thesis, University of Birmingham, 2013. http://etheses.bham.ac.uk//id/eprint/4325/.

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In chemical literature much information is given in the form of diagrams depicting chemical structures. In order to access this information electronically, diagrams have to be recognized and translated into a processable format. Although a number of approaches have been proposed for the recognition of molecule diagrams in the literature, they traditionally employ procedural methods with limited flexibility and extensibility. This thesis presents a novel approach that models the principal recognition steps for molecule diagrams in a strictly rule based system. We develop a framework that enables the definition of a set of rules for the recognition of different bond types and arrangements as well as for resolving possible ambiguities. This allows us to view the diagram recognition problem as a process of rewriting an initial set of geometric artefacts into a graph representation of a chemical diagram without the need to adhere to a rigid procedure. We demonstrate the flexibility of the approach by extending it to capture new bond types and compositions. In experimental evaluation we can show that an implementation of our approach outperforms the currently available leading open source system. Finally, we discuss how our framework could be applied to other automatic diagram recognition tasks.
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42

Gooch, Carolyn A. "Quantitative structure-activity relationships : a biophysical, chemical and calorimetric study." Thesis, Royal Holloway, University of London, 1988. http://repository.royalholloway.ac.uk/items/26719d55-b208-4995-bef0-92e4f0f80c0e/1/.

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Quantitative structure-activity relationships (QSAR) rationalize interrelation between molecular structure and biological response in terms of either physicochemical parameters, as in linear free energy relationships (LFER), or via purely empirical parameters, as is the case for De Novo schemes. In LFER the leading process is often the partitioning of a compound between two solvent phases, taken to represent the transfer of a drug molecule across a biological membrane. This study has investigated the partitioning behaviour of three series of hydroxybenzoate esters, viz. o-, m- and predominantly p-esters, the latter being preservatives in pharmaceutical formulations. The thermodynamic parameters AH, AG and AS for the transfer process were derived in an attempt to establish a QSAR. on a fundamental thermodynamic basis. Such parameters have identifiable physicochemical meaning and lend themselves more readily to interpretation. This facilitates application to alternative systems. A new Gibbs function factor analysis was developed and utilized to obtain thermodynamic contributions for parent and incremental methylene group portions of thestudy molecules. The empirical Collander equation for interrelation of various solute/solvent systems was also rationalized on a thermodynamic basis. Further extension of the Gibbs function factor analysis allowed scaling of "solvent" systems including chromatographic packings, solvents and liposomes. The scheme indicated capacity for optimized selection of bulk solvent systems to mimic biological membranes. A novel analytical procedure for direct measurement of biological response was developed. The bioassay appeared capable of discrimination i) between the closely related structural homologues, ii) between gram-negative and gram-positive bacteria, and further, iii) between certain cell batches of the same bacteria type. Also, the bioassay demonstrated a Collander interrelation between the two bacteria types. Flow microcalorimetry was the technique employed to measure thermal response of respiring E. coli and Staph, aur. bacteria. The modification of biological response with drug concentration was quantitated and a log dose max term was derived for each homologue. The results indicated potential for a predictive, additive structure-activity scheme based on assessment of biological response (BR) direct rather than through f(BR) via physicochemical or empirical parameters.
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43

Qian, Kun. "Effect of Chemical Structure on Tribological Behavior of Base Oils." Miami University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=miami1619112362542091.

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44

Knight, Daniel William. "Reactor behavior and its relation to chemical reaction network structure." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1438274630.

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45

Yang, Emma. "Chemical, metabolic and structure-activity relationships to probe abacavir toxicity." Thesis, University of Liverpool, 2014. http://livrepository.liverpool.ac.uk/2008286/.

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Adverse drug reactions (ADRs) are responsible for an increasing number of hospitalised patients, with the large majority of these ADRs classed as either type A or type B. Drug hypersensitivity reactions fall within the type B category and one such drug responsible for this form of ADR is abacavir (ABC). ABC, a nucleoside reverse transcriptase inhibitor, is used to treat the HIV-1 virus. It is responsible for a potentially life-threatening type IV hypersensitivity reaction which occurs in patients bearing the HLA-B*57:01 allele. Although many mechanisms have been proposed, it was the objective of this research to examine all these previous proposals to further extend and develop the mechanism of ABC toxicity. In Chapter 2, deuterated-ABC (D2-ABC) was designed and synthesised where the two 5'-H atoms were replaced with two 5'-D atoms. The design of this analogue was intended to retard the oxidative metabolism of ABC to its aldehyde and carboxylic acid metabolites. The synthesis of this compound was paramount to investigating this metabolism and through a series of metabolic experiments, described in Chapter 3, a kinetic isotope effect between ABC and D2-ABC was determined, ultimately showing an altered metabolism between the two compounds. To investigate binding of ABC within the HLA-B*57:01 protein, analogues of ABC, with alterations at varying positions within the molecule, were required. Using a racemic method, ABC enantiomers were synthesised and ABC’s enantiomer failed to stimulate T-cells in vitro. The creation of further analogues required the development of an asymmetric synthetic route. A total synthetic method was desired to synthesise intermediates to be used in future analogue synthesis. Finally, as described in Chapter 5, a range of 6-position analogues were designed, using a structure-activity relationship method, and synthesised, to further investigate the altered repertoire mechanism. These analogues, consisting of primary and secondary amine and oxy moieties, were subjected to in vitro immunological assays to determine their stimulation of T-cells. Additionally, the synthesised analogues were modelled in silico using molecular docking within the HLA protein. The in silico results assisted in explaining the basis of such T-cell activation/inactivation and will direct future analogue design. IC50 and EC50 values were determined for analogues that presented a negative T-cell response and a compound showing positive values was subjected to further pharmacokinetic testing. The oxidative metabolism of ABC was affected by isotopic substitution, but initial results have shown no altered T-cell stimulation of D2-ABC compared to ABC. This mechanism cannot be discarded, with further investigational work required. However, the synthesised 6-position analogues have assisted in further examining the altered repertoire mechanism and initial findings have enabled further understanding of the binding of ABC within HLA-B*57:01. This mechanism of ABC toxicity appears paramount to others proposed and the results presented in this thesis support this. Additional analogue synthesis and in vivo experiments will assist in confirming this further.
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46

Jabur, Alaa Wazir. "Investigations of the physical and chemical structure of archaeological fibres." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/investigations-of-the-physical-and-chemical-structure-of-archaeological-fibres(a2683a0a-764b-4287-9fa2-1a48b7cee06e).html.

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Investigations of the physical and chemical structure of archaeological fibresArchaeological fibres can be defined as natural fibres that belong to different time periods, which found in cemeteries or excavation sites. The preservation conditions cause degradation, mineralisation and sometimes a complete deterioration of these fibres, because the chemical and physical structure of the fibres changed over time in response to the specific burial environments. The ancient fibres from different archaeological sites were analysed by several non destructive analytical techniques such as optical Microscopy, Environmental Scanning Electron Microscopy, Attenuated Total Reflectance FTIR and Wide Angle X-Ray Scattering Analysis as well as destructive analytical techniques such as Scanning Electron Microscopy, Transmission Fourier Transform Infrared Spectroscopy, Energy Dispersive X-Ray Spectroscopy and Differential Scanning Calorimetry. These analytical techniques showed that keratin fibres from a central European climate have a larger damage at the fibre surface compared with frozen conditions. While bog conditions were the best in preserving the surface. FTIR analysis provides information about cystine oxidation changes in keratin fibres. For all ancient keratin fibres showed a silica peak at 1030 cm-1 which affected the symmetric cysteic acid peak at 1040 cm-1. For this reason the asymmetrical cysteic acid peak 1175 cm-1 was used for identification of cystine oxidation changes. Transmission FTIR gives a better view of the overall chemical changes in both cortex and cuticle compared to ATR analysis. All ancient wools and highly medullated Iceman deer hairs showed the highest concentration of cysteic acid compared with human hair and goat hair. Also it was shown that warm conditions have bigger effect on both the degree of oxidation of cystine and the ions uptake from the environment. The modulated DSC analysis gives a better view on the degree of degradation of hair proteins compared to WAXS analysis. To get a reliable result it is important to correct the DSC data according to the protein content of the fibre.
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47

Broadley, Michael Ward. "Tracing mantle structure and chemical evolution using noble gas isotopes." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/tracing-mantle-structure-and-chemical-evolution-using-noble-gas-isotopes(a231d757-1535-4edd-899c-b2ecff0accf9).html.

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The mantle is the largest reservoir of many of the Earth’s volatile species. Detailed isotopic studies of noble gases within the mantle volatiles have demonstrated that they are of a primordial origin, which have been trapped in the mantle since the Earth’s accretion. This original volatile signature has continually evolved over time, due to the production of in situ radiogenic isotopes and through the recycling of surface volatiles back into the mantle (Lupton and Craig, 1975; Holland and Ballentine, 2006). The study of noble gases within magmatic samples has enabled the composition and structure of the mantle to be determined and has distinguished the multiple volatile reservoirs (primordial, crustal, marine etc.) that have contributed to the mantle composition sampled. Together with the halogens (Cl, Br and I) they represent key tracers of volatile transport processes in the Earth. Therefore a combined analytical approach including the halogens and noble gases is not only be able to track the influx of surface volatile into the mantle, but also provide a greater understanding to the fundamental controls of transport, storage and partitioning of volatiles within the mantle. A combined noble gas and halogen study was undertaken on three different geological samples sets to determine how surface volatiles interact with the mantle on a variety of different scales. Firstly continental xenoliths from the Western Antarctic Rift were analysed to establish the role of subduction volatiles in the creation of the rifts volcanic products. The xenoliths have 3He/4He ratios of 7.5RA indicating that the rift is dominated by the rising asthenospheric mantle. However the Br/Cl and I/Cl ratio and heavy noble gases within the xenoliths indicate that marine derived volatiles have been incorporated into the mantle beneath the rift and may have provided and fundamental control on the formation of the rift itself. Secondly the role of surface contamination on mantle samples has been evaluated. A transect along a MOR pillow basalt has been analysed for its halogen concentrations in conjunction with the previously determined noble gases. The outer sections are enriched in Cl relative to Br and I due to the assimilation of a high salinity brine during eruption. In contrast the crystalline interior of the pillow has MORB like Br/Cl and I/Cl ratios but elevated 132Xe/36Ar ratios indicative of the incorporation of pelagic sediments. This small scale analytical approach has shown that submarine pillow basalts are prone to contamination from the surrounding marine environment and provides a method for the identification and quantification of marine contamination. Finally the halogens within olivine phenocrysts from three Emperor Seamounts have been analysed to determine the distribution of the halogens within the lower mantle. The I/Cl ratio of the samples evolves from a MORB-like ratio in the oldest seamount to elevated values similar to sedimentary pore fluids and chondrites in the younger seamounts. This indicates that the Hawaiian mantle plume contains isolated pockets of subducted or primordial material which have been isolated from whole mantle mixing and have therefore retained a halogen signature distinct from the average mantle values.
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48

Sohn, Young-Soo. "MEMS based microfluidic structure for biological and chemical sensor array /." Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3008446.

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49

Bagchi, Bhaskar. "Quantum chemical calculation and structure activity relationship of bioactive terpenoids." Thesis, University of North Bengal, 2016. http://ir.nbu.ac.in/handle/123456789/2762.

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50

Bancroft, Naomi. "Infrared behavior of structure I methane and carbon dioxide hydrates." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99402.

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Fourier transform infrared (FTIR) spectroscopy is commonly used in solution crystallization studies to monitor the crystal formation process. This analysis reflects the molecular vibrations within the solution. A crystallization process that is currently a very popular area of study is hydrate formation due to the possible application of gas hydrate research in the energy sector. A study of molecular vibrations was performed on two types of structure I gas hydrate, methane and carbon dioxide. Experiments were performed with a specialized high pressure sample cell placed inside an FTIR spectrometer. The experimentation was carried out at 253.15 K for both the methane and carbon dioxide systems and a pressure range of 2100 to 6800 kPa for the methane system and 1400 to 1700 kPa for the carbon dioxide system. This line of experimentation was able to assist in mapping the IR behavior of the hydrates studied and establish the presence of hydrate within a sample.
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