Dissertations / Theses: 'Characterization and analytical techniques'

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Pretorius, Nadine Odette. "Multidimensional analytical techniques for the characterization of aliphatic polyesters." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/80127.

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Thesis (PhD)--Stellenbosch University, 2013.
ENGLISH ABSTRACT: Complex polymers are defined by their distributive properties with respect to molecular weight, chemical composition, functionality and molecular topology. As a result, polymer properties are very frequently determined not only by one of these entities but by the correlation of two or more distributions. Aliphatic polyesters are industrially implemented in high performance coatings, paints and varnishes. However, it is typically difficult to correlate the resulting properties with the synthesis parameters as these polymers vary in reactivity and application properties. Copolyester synthesis by direct polyesterification is often assumed to produce randomized products due to the mechanisms involved in stepwise polymerization. The formation of cyclic products by intramolecular reactions of hydroxyl (OH) and carboxylic (COOH) functional groups, sidereactions such as transesterification, alcoholysis, and ester-ester interchange allow even further randomization, enabling a highly complex system. Therefore, in addition to molecular weight distribution, polyesters exhibit chemical composition, functionality type as well as branching distributions, classifying them as complex polymeric systems. The different methods of polymer chromatography in combination with sophisticated spectrometry techniques are useful tools for enabling the full description of the molecular heterogeneity of these complex polyesters. The present study entails method development of different modes of chromatography and mass spectrometry along with their combination, to facilitate the analysis of the various distributions of two model polyester systems, phthalic and maleic anhydride, respectively, in combination with propylene glycol. Gradient HPLC analysis enabled an oligomeric separation based on chemical composition of the respective anhydride/propylene glycol samples. Its off-line coupling to MALDITOF MS and ESI-QTOF MS revealed the presence of several distributions of varying endgroup functionality type and molecular weight distributions at different intervals throughout the polymerization. In addition, online gradient HPLC x size exclusion chromatography (2D-LC) was conducted to obtain the dual chemical composition-molecular weight (CCD-MWD) distribution. The combination of the different coupling techniques provided the opportunity to a more in-depth analysis of the structure-property relationships.
AFRIKAANSE OPSOMMING: Komplekse polimere word gedefinieer deur hul verdelings eienskappe ten opsigte van molekulêre massa, chemiese samestelling, funksionaliteit en molekulêre topologie. Gevolglik, word hul eienskappe dikwels bepaal deur nie net een van hierdie entiteite nie, maar ‘n korrelasie van twee of meer verdelings. Alifatiese poliësters word industrieel geϊmplimenteer in hoë werkverrigting bestrykings, verwe en politoere, dog is dit tipies moeilik om die uiteinde eienskappe met die verwante sintese parameters te korrelleer, aangesien die polimere varieer in reaktiviteit en toepassingseienskappe. Ko-poliëster sintese vanaf direkte poliësterivering word dikwels aanvaar om willekeurige produkte op te lewer as gevolg van die meganismes wat betrokke is tydens trapgroei polimerisasie. Die produsering van sikliese produkte weens intra-molekulêre reaksies van hidroksiel(OH) en karboksiel (COOH) verwante funksionele groepe, newereaksies soos transverestering, alkoholise en ester-ester verwisseling, het verdere ewekansigmaking tot gevolg wat ‘n hoog gekomplekseerde sisteem tot gevolg het. Benewens die molekulere massa verdeling, vertoon poliësters dus chemiese samestelling, funksionaliteit tipe so wel as vertakkings verdeling wat hul as komplekse polimeer sisteme klassifiseer. Die verskillende metodes van polimeer chromatografie in kombinasie met gesofistikeerde spektrometriese tegnieke dien as nuttige bronne vir die volledige beskrywing wat betref die molekulêre heterogeniteit van komplekse poliesters. Die huidige studie stel metode ontwikkeling van verskillende modus van chromatografie, massa spektrometrie sowel as hul aaneenvoeging bekend, om die die verskillende verdelings van twee model poliester sisteme, ftaal- en maleϊensuuranhidried onderskeidelik in kombinasie met propileenglikol, suksesvol te analiseer. Gradiënt hoë-druk vloeistof chromatografie (HPLC) analise het ‘n oligomeriese skeiding, gebaseer op die chemiese samestelling van die verskeie anhidried /propileenglikol monsters, opgelewer. Die nie-gekoppelde skakeling met matriks-assisteerdelaser/ desorpsie-ionisasie tyd-van-vlug (MALDI-TOF) en elektron-sproei-ionisasie kwadrupool-tyd-van-vlug (ESI-QTOF) massa spektrometrie het die teenwoordigheid van verskeie verdelings van varieërende endgroep funksionaliteit tipe en molekulêre verdelings by verskillende intervalle tydens die polimerisasie aan die lig gebring. Gekoppelde skakeling van gradient HPLC en grootte uitsluitings chromatografie is ook uitgevoer om die tweedelige chemiese samestelling-molekulere massa verdeling te bepaal. Aaneenvoeging van die verskeie skakelings tegnieke het die geleentheid gebied om ‘n deeglike studie van die struktuureienskappe verhoudinge suksesvol uit te voer.

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Li, Linlin. "Microstructure characterization of polymers by modern NMR techniques." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1353000762.

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Maku, Lebogang Jennifer. "Identification and characterization of additives in colourants by advanced analytical techniques." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/98084.

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Thesis (MSc)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: Various types of anionic, non-ionic, cationic and zwitterionic additives are used in the coatings industry for the production of paints and colourants. These additives are added to enhance properties such as stabilization of pigment dispersions, wetting of pigments and improvement of open time and freeze/thaw stability. Very often the exact chemistry of these commercial additives is unknown and this is a limitation for new product developments. The identification and characterization of these multi-component polymeric materials continues to be a challenging task. This research presents the use of various advanced analytical techniques to identify and characterize commercial additives that are used in a multi-component colourant formulation. The focus of the present study is on additives that are based on poly(ethylene glycol) (PEG). The molar mass distribution of PEG-based additives was determined with liquid chromatography coupled to mass spectrometry (LC-MS) using solvent gradient elution and at critical conditions of adsorption (LCCC) of PEG. Using the combination of LC-MS, proton nuclear magnetic resonance spectroscopy (1H NMR), pyrolysis gas chromatography (py-GC-MS) and Fourier transform infrared spectroscopy in attenuated total reflectance mode (FTIR-ATR), different additives were identified in terms of the number and type of polymer end groups. The efficiency of the extraction and identification protocol was demonstrated for a blend of additives in a colourant formulation.
AFRIKAANSE OPSOMMING: Verskeie tipes anioniese, nie-ioniese, kationiese en zwitterioniese bymiddels word gebruik in die bedekking nywerheid vir die vervaardiging van verwe en kleurmiddels. Hierdie bymiddels word bygevoeg om sekere eienskappe, soos die stabilisering van pigment dispersie, benatting van pigmente en die verbetering van ope tyd en vries/dooi stabiliteit te versterk. Dikwels is die presiese chemie van hierdie kommersiële bymiddels onbekend en het dit ŉ beperking vir nuwe produk ontwikkeling tot gevolg. Die identifisering en karakterisering van hierdie meer-komponent polimeriese materiaal duur voort om ŉ uitdagings te wees. Hierdie navorsingstudie stel voor die gebruik van verskeie tegnieke om kommersiële bymiddels te identifiseer en karakteriseer wat in meer-komponent kleurmiddel formulasies gebruik word. Die fokus is geplaas op bymiddels wat gebaseer is op poli(etileen glikol) (PEG). The molêre massa verdeling van PEG-gebaseerde bymiddels was bepaal met vloeistofchromatografie gekoppel tot massaspektrometrie (VC-MS) met die gebruik van oplosmiddel gradient eluasie en by kritiese toestande van adsorpsie (VCKT) van PEG. Deur die kombinasie van VC-MS, proton kern magnetiese resonansie spektroskopie (1H KMR), pirolisegaschromatografie (pir-GC-MS) en Fourier-transformasie infrarooi spektroskopie in verswakking totale refleksie modus (FTIR-VTR), is verskillende bymiddels geïdentifiseer in terme van die hoeveelheid en tipe polimeer eindgroep teenwoordig. Die doeltreffendheid van die ekstrahering en identifisering protokol is gedemonstreer vir ŉ mengel van bymiddels in ŉ kleurmiddel formulering.

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Lenart, William R. "EXPANDING EXPERIMENTAL AND ANALYTICAL TECHNIQUES FOR THE CHARACTERIZATION OF MACROMOLECULAR STRUCTURES." Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1584358701735061.

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Matos, João Tiago Viana de. "Organic matter in atmospheric aerosols: molecular characterization using high-resolution analytical techniques." Doctoral thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/22234.

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Doutoramento em Química
Esta dissertação focou-se na caracterização química de amostras de aerossóis atmosféricos finos recolhidas numa região urbana situada na costa da Europa Ocidental, durante oitenta semanas, e representativas das diferentes estações do ano. Os dados adquiridos proporcionam um maior conhecimento sobre a composição molecular da fração orgânica dos aerossóis, bem como uma visão global sobre a contribuição de diferentes fontes e sazonalidade dos componentes carbonáceos e inorgânicos nos aerossóis. A cromatografia líquida bidimensional abrangente foi utilizada para investigar a heterogeneidade química e mapear a hidrofobicidade vs. distribuição de peso molecular das frações de ácidos mais hidrofóbicos da matéria orgânica solúvel em água (WSOM, na sigla em inglês) de aerossóis atmosféricos, revelando que a WSOM, amostrada nas estações quentes, é enriquecida em estruturas alifáticas, enquanto que a WSOM recolhidas nas estações frias contém estruturas com ligações  conjugadas juntamente com estruturas alifáticas. Foi também realizado uma comparação das características estruturais da matéria orgânica presente em extratos aquosos e extratos alcalinos, sequencialmente extraídos de aerossóis finos. Para isso, foi utilizado um método quimiométrico multidirecional para decompor conjuntos de espectros de fluorescência em modo matriz excitação-emissão de WSOM e de matéria orgânica solúvel em meio alcalino (ASOM, na sigla em inglês), numa tentativa de identificar as estruturas fluorescentes atmosfericamente mais relevantes, bem como a sua variabilidade anual. A metodologia utilizada demonstrou diferenças sazonais num dos componentes fluorescentes identificados nas amostras de WSOM, contrastantes com os resultados obtidos para as amostras ASOM, nas quais os componentes identificados foram constantes ao longo do ano. A espectroscopia de ressonância magnética nuclear (RMN) de protão foi igualmente utilizada para investigar e comparar as características estruturais das frações de WSOM e ASOM, mostrando que estas frações contêm grupos funcionais de protão semelhantes, mas com uma diferente distribuição relativa ao longo do ano. As amostras recolhidas nas estações frias apresentam um carácter menos alifáticos e oxidado e com uma maior contribuição de estruturas aromáticas que as amostras recolhidas nas estações quentes. Adicionalmente, a aplicação das técnicas bidimensionais (2D) de RMN forneceram uma excecional resolução e uma incomparável representação da assinatura molecular das amostras, o que permitiu obter um perfil detalhado da composição estrutural destas frações, assim como decifrar as suas principais fontes de emissão ao longo do ano. As frações ASOM são menos hidrofílicas e estruturalmente diversas das frações de WSOM, sendo estas últimas constituídas maioritariamente por estruturas alifáticas ramificadas ricas em hétero-átomos, de origem primária (antropogénica e natural) e secundária. Estruturas do tipo da lignina, sacarídeos, dissacarídeos, e anidrosacarídeos foram identificados nas amostras de WSOM, refletindo a influência queima de biomassa. Os dados espectrais obtidos para cada ligação H-C identificada foram também utilizados para construir um modelo estrutural semiquantitativo da fração WSOM, o qual poderá ser utilizado em futuros estudos acerca do efeito da composição química e estrutural dos aerossóis orgânicos no respetivo comportamento e impacto na química da atmosfera.
This dissertation focus on the chemical characterization of fine atmospheric aerosol samples collected at an urban site in the Western European Coast, during eighty weeks, representative of different seasons. The acquired data set provide a comprehensive and new insight on the molecular composition of the organic fraction of the aerosol components, as well as, provide a seasonal source apportionment overview of both carbonaceous and inorganic aerosol components. Comprehensive two-dimensional liquid chromatography was introduced to investigate the chemical heterogeneity and map the hydrophobicity vs. molecular weight distribution of the most hydrophobic acid fractions in water-soluble organic matter (WSOM) from atmospheric aerosols, revealing that the WSOM samples collected in warm seasons are enriched in aliphatic structures, while those from colder seasons exhibit a higher degree of structures with conjugation of -bonds alongside aliphatic structures. A comparison of the features of the organic matter present in water and alkaline extracts, sequentially extracted, from fine aerosol samples during different seasons, are also carried out. For that, a multiway chemometric method was used to decompose sets of excitation-emission matrices fluorescence spectra of WSOM and alkaline-soluble organic matter (ASOM), in an attempt to identifying the most atmospherically-relevant fluorescent structures, as well as their variability over seasons. The method shows differences between the colder and warmer seasons in the fluorescence map of one WSOM fluorescent component, which contrast with the results obtained for the ASOM, where the fluorescence signatures were found to be constant along the seasons. Proton nuclear magnetic resonance (1H NMR) spectroscopy was used for investigating and comparing the structural features of WSOM and ASOM, showing that these fractions hold similar 1H functional groups; however, they differ in terms of their relative distribution throughout the different seasons. Samples collected during the cold seasons have a less aliphatic and oxidized character and higher contributions from aromatic groups than those from warmer conditions. Furthermore, a synergistic combination of 2D NMR techniques provided an exceptional resolution and depicted unsurpassed resolved molecular signatures, which allowed portraying the annual background of the structural composition of these fractions, as well as deciphering their major source types over seasons. The ASOM fractions are less hydrophilic and structurally diverse than their WSOM counterparts. This latter component is mostly composed of heteroatom-rich branched aliphatics, having both primary (natural and anthropogenic) and secondary origin. Lignin, disaccharides, and anhydrosaccharides signatures were also identified in the WSOM samples, reflecting the biomass burning influence. The derived dataset on the H–C molecules backbone were also used to build a semi-quantitative structural model of WSOM, which can be used as a proxy to further distil key features on the atmospheric behaviour of organic aerosols.

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Sinner-Hettenbach, Martin. "SnO 2 (110) and Nano-SnO 2 characterization by surface analytical techniques /." [S.l. : s.n.], 2000. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB8884756.

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Dixon, Daniel Wayne. "Characterization of Commercial Pectin Preparations by Spectroscopic and Chromatographic Techniques." Digital Commons @ East Tennessee State University, 2008. https://dc.etsu.edu/etd/1910.

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Pectin has a long history as a food additive. However, elucidation of its fine structural and property relationships remains elusive. Recent research has focused on pectin's ability to complex with divalent heavy metals to aid in characterizing it. Commercial pectins of unknown composition were obtained from local grocers. Purified pectin samples from orange peel, lemon peel, and apple pomace, each of low and high levels of methyl esterification and of unknown distribution pattern were also purchased. Instead of metal complexation, several highly absorbing dyes such as Ruthenium Red, Nile Blue, and Acridine Orange were used to complex with the pectins and their resulting UV-Vis spectral patterns were employed to determine if one can characterize the different pectins. Chemometric methods are also included to aid in distinguishing them apart.

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Gebremichael, Ermias. "Pharmaceutical Eutectics: Characterization and Evaluation of Tolbutamide and Haloperidol using Thermal Analytical and Complementary Techniques." Toledo, Ohio : University of Toledo, 2010. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=toledo1271439418.

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Thesis (M.S.)--University of Toledo, 2010.
Typescript. "Submitted to the Graduate Faculty as partial fulfillment of the requirements of the Master of Science degree in Pharmaceutical Sciences with Industrial Pharmacy Option." "A thesis entitled"--at head of title. Title from title page of PDF document. Bibliography: p. 87-102.

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Sinner-Hettenbach, Martin. "SnO2(110) and Nano-SnO2 characterization by surface analytical techniques = SnO2(110) und Nano-SnO2 /." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=963195433.

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Danziger, James Lee. "Characterization of molecular semiconductor and multilayer molecular organic photoconductor interfaces by photoelectrochemistry and surface analytical techniques." Diss., The University of Arizona, 1990. http://hdl.handle.net/10150/185217.

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Organic semiconductor thin films are of interest to us for a variety of molecular electronic applications, including solar cells, chemical sensors, and nonlinear optical devices. We have been seeking unusual new ways of controlling the composition and long-range molecular structure of these materials through the use of vacuum deposition techniques which mimic, in some ways, those used for epitaxial layer growth in inorganic materials. Thin films of perylene tetracarboxylic dianhydride (PTCDA) have been examined as electrodes and photoelectrodes on both metal and metal oxide substrates. In contrast to most previous studies of phthalocyanine thin films, these materials behaved in such a way as to suggest n-type character, i.e. dark electron transfer reactions were facile in negative potential regions with solution redox couples, and little dark electrochemistry could be observed in regions of positive potentials. It is likely that junction formation occurs only as a result of illumination, with different rates of interfacial hole and electron injection and transport, at the PTCDA/electrolyte interface. Electron microscopy of the PTCDA films indicated that they were deposited as elongated crystallites, with relatively large spaces between individual crystallites, which strongly affected their dark and photoelectrochemical behavior, especially on Au substrates. Electrochemical polymerization of α-napthol was carried out to passivate sites that were electrochemically active in the dark, a treatment which greatly enhanced the overall electrochemical activity of these PTCDA thin films. A variety of p-n heterojunction-like structures, created from thin film molecular materials (vanadyl phthalocyanine (VOPc) and perylene tetra-carboxylic dianhydride (PTCDA)), have been nondestructively explored by photoelectrochemical techniques and UHV surface analytical techniques. Vacuum deposited bilayers and multilayers of these thin films behave like "p-n" diodes over a narrow potential window. The open circuit photopotential is determined by the junction potential formed at the Pc/PTCDA interface. It was found that the transient photocurrent (using a modulated light source) in multilayer VOPc/PTCDA assemblies was directly related to the number of interfaces present, consistent with the idea that exciton dissociation is localized primarily to such an interface, and is the photocurrent limiting process.

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MacKenzie, Sabrena E. "Isolation and characterization of new fumonisins from Fusarium moniliforme NRRL 13616 and development of new analytical techniques." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ36942.pdf.

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Chen, Siying. "Characterization of crystalline and solution-processable phthalocyanine assemblies by electrochemical, photoelectrochemical, and surface spectroscopic techniques." Diss., The University of Arizona, 1996. http://hdl.handle.net/10150/282120.

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Ultrathin organized films of organic electronic materials, such as phthalocyanines (Pc), are promising for both fundamental and applied studies due to their special optical, electronic and photoconductive properties. The studies presented in this dissertation include fabrication of ultrathin molecular assemblies by molecular beam epitaxy and Langmuir-Blodgett techniques. The degree of molecular order, extent of charge transfer and the morphology within these films, assessed by methodologies, such as photoelectrochemistry, electrochemistry, surface analysis and optical spectroscopy were discussed and characterized. Under high vacuum condition, a wide range of ordered structures of some trivalent metal phthalocyanines, such as GaPc-Cl, InPc-Cl and AlPc-F, can be fabricated. These materials exhibit "layer-by-layer" growth on the single crystal SnS₂ surface when deposited by molecular beam epitaxy (MBE). The MBE technique allows for closer packing of these highly ordered phthalocyanines than in self-assembled (SA) or Langmuir-Blodgett (LB) thin films, due to the lack of hydrocarbon side chains which are necessary for control of molecular architecture during SA or LB depositions. Several new solution processable substituted phthalocyanines are introduced, which due to their strong self-assembled tendency, may be suitable for the formation of well organized thin films by SA and LB techniques. It is found that the types of the substituents attached to the Pc rings play a significant role in determining both the aggregation tendency and the electrochemical properties of Pcs. Surface pressure-area isotherms of these substituted phthalocyanines show that there can be one or two stable phase transition regimes for monomolecular film at the air/water interface. On-trough spectroscopic studies of benzylalkoxy substituted phthalocyanines show that in the pressure-area region prior to the formation of the first stable phase extensive aggregation has occurred. Electrochemical studies of fully compressed films of substituted phthalocyanines on certain substrates show the presence of multiple electroactive domains, controlling the oxidation or reduction process of the Pc rings. Spectroelectrochemical studies of LB films of CuPcOC₂OBz suggest that the presence of both monomer and aggregates leads to the two separate oxidation processes.

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Nielsen, Michael Lund. "Characterization of Polypeptides by Tandem Mass Spectrometry Using Complementary Fragmentation Techniques." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7409.

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Joyce, Karen Elaine. "Development of Reactive Ion Scattering Spectrometry (RISS) as an Analytical Surface Characterization Technique." Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/193593.

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Reactive ion scattering spectrometry (RISS) utilizing low energy (tens of eV) polyatomic ions was employed to characterize self-assembled monolayers (SAMs) on gold. The terminal composition of halogenated SAMs, chemisorption motifs of disulfide and diselenide SAMs, and electron transfer properties of molecular wire containing SAMs were interrogated to develop the versatility of RISS as an analytical surface characterization technique.Novel halogen terminated SAMs were examined for their ability to convert translational to vibrational energy of colliding projectile ions. A general increasing energy deposition trend correlated with increasing terminal mass with the exception of the iodine functionality. Increased amounts of surface abstractions and sputtering from C12I suggest competitive ion-surface interactions account for less than predicted energy deposition results. Mixed films of CH2Br and CH3 terminal groups elucidated interfacial surface crowding discerned by energy deposition results.Thiol and disulfide based SAMs were shown by RISS comparisons to be dissimilar in structure. Terminal orientation, however, was the same based on ion-surface reactions, disproving the proposed dimer model of disulfide SAMs. Ion-surface reactions and electron transfer properties of disulfide surfaces suggested greater percentages of c(4x2) superlattice structure than in thiol SAMs. Based on increased hydrogen reactivity, decreased methyl reactivity, and increased energy deposition results, diselenide based SAMs were more disordered than S-Au based SAMs. Electron transfer results monitored through total ion currents (TIC) showed Se-Au contacts are more conductive than S-Au attachments.Molecular wire candidates whose electron transfer capabilities are difficult to characterize by traditional techniques were characterized by RISS after being doped into matrix SAMs. Electron transfer properties were dependent on the isolating SAM matrix, dipole moments of the wires, and the potential applied to the surface. Changes in surface voltage dictated molecular wire geometry and electron transfer. Wires were annealed into preferential geometries by colliding ions, but did not operate as switches.While not related to the advancement of RISS, structural elucidation of the pharmaceutical carvidioliol was investigated by collision-induced dissociation, surface-induced dissociation, sustained off-resonance irradiation, and sustained off-resonance irradiation-resonant excitation and through gas-phase hydrogen/deuterium exchange. This molecule fragmented easily by all methods and demonstrated the chemical specificity of gas-phase hydrogen/deuterium exchange experiments.

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Casiano-Maldonado, Madalis. "Mass Spectrometry Techniques for the Characterization of Synthetic Polymers, Biopolymers, Biodegradation Products and Their Interactions." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1332962590.

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Brown, Anna Laura. "Bismuth Nanoparticles as Medical X-ray Contrast Agents: Synthesis, Characterization and Applications." PDXScholar, 2013. https://pdxscholar.library.pdx.edu/open_access_etds/1523.

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Bismuth based nanomaterials have recently attracted attention as heavy element X-ray contrast agents because of the high atomic number and predicted biological compatibility of bismuth. Nanoparticle X-ray contrast agents may enable a number of novel medical imaging applications, including blood pool and site-directed imaging. However these hypothetical applications are hindered by lack of suitable synthetic methods for production of imaging agents. This dissertation describes synthesis of a novel class of bismuth nanoparticles that are aqueously stabilized using poly and monosaccharides. These particles are synthesized using highly biologically compatible reagents and are oxidatively stable in water and in moderately basic buffered solutions. Bismuth nanoparticles stabilized by the polysaccharide dextran have a large hydrodynamic radius and a relatively small bismuth nanocrystal core (4% bismuth by volume.) Glucose-capped particles have a much higher ratio of bismuth by volume (>60%), and experimental CT scans of these particle solutions demonstrate higher X-ray contrast versus a current clinically used radiocontrast agent. Additional syntheses of hydrophobic organoamine-capped bismuth nanoparticles by reduction of an iodobismuth cluster, and development of other X-ray contrast materials, such as a radiopaque surgical sponge marker and ink, using bismuth micoparticles produced by a top-down ball milling method, are also described.

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Heuett, Nubia Vanesa. "Target and Non-target Techniques for the Quantitation of Drugs of Abuse, Identification of Transformation Products, and Characterization of Contaminants of Emergent Concern by High Resolution Mass Spectrometry." FIU Digital Commons, 2015. http://digitalcommons.fiu.edu/etd/2194.

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Development and application of target and non-target techniques for routine analysis, identification of transformation products, and characterization of unknown compounds in water matrices using liquid-chromatography high-resolution mass spectrometry (HRMS) were explored in this dissertation. A novel analytical method based on online-SPE-LC-HRMS was developed for the detection of 18 drugs of abuse (DOAs) in raw sewage water from a college campus. Results showed the presence of 14 DOAs for which amphetamine and 11-nor-9-carcoxy-THC (THC metabolite) were the most prevalent and had the highest potential consumption rates. A second study dedicated to the identification of transformation products (TPs) generated from DOAs was conducted using a combination of HR-MS/MS and metabolic identification and structural elucidation software. Findings confirmed the presence of multiple phase I and II DOA TPs (n=35) in raw sewage influents. Concentrations of all TPs were estimated based on the parent DOAs response factors, and used to calculate the percent mole fraction contributions of each TP to the parent concentrations. High abundance and frequency (compared to the parent drug) was determined for 9 of the TPs coming from drugs like oxycodone, morphine, codeine, methadone, LSD, cocaine, and MDEA. Non-target analysis using HRMS was explored as a tool to characterize, and compare a series of interconnected water matrices along a river system. Several thousands of formulae were generated using automated heuristic rules from the full-scan acquisition at 140,000 resolution. Samples were part of a trajectory covering upstream, effluent, effluent mixing zone, downstream, drinking water intake, and treated drinking water locations. Graphical representations of the data were used to evaluate commonalities among the system. Using this approach, a total of 64 recalcitrant components were identified throughout the samples downstream of the effluent release point. Using a combination of MS/MS and computer-aid software techniques 4 out of the 64 compounds were tentatively confirmed. In addition, comparison of drinking water intake and finalized treated drinking water sites showed the presence of 1,152 chemical entities that were common to both locations; and 1,857 that were unique to the treated drinking water. Therefore, this non-target technique could be used to identify the potential formation of treatment byproducts.

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Mastricola, Nicholas Palma. "Nonlinear Stiffness and Edge Friction Characterization of Coned Disk Springs." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1480346443676492.

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Abdelraouf, Mostafa. "Virtual reality for the characterization of blood vessel to airway geometric relationships." Thesis, University of Iowa, 2018. https://ir.uiowa.edu/etd/6355.

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An increase in the cross-sectional area (CSA) of the pulmonary arteries has been implicated in the progression of emphysema in COPD patients. Standardization of vessel size requires matching segments of the airway with their corresponding blood vessels. Automated matching is still error-prone, and manual matching by sifting through 2D slices is tedious and time-consuming. We propose a virtual reality (VR) system for the visualization of the airway and the vascular tree as a means of streamlining the verification of appropriate airway/vascular segment pairs selected for quantitation of arterial CSAs. In this work, we outline the technical specifications and design considerations and challenges for such system; we also compare user's performance on the proposed system with the conventional 2D method.

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Vabbilisetty, Pratima. "Fabrication and Characterization of Substrate Materials for Trace Analytical Measurements by Surface Enhanced Raman Scattering (SERS) Spectroscopy Technique." Connect to resource online, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1231794465.

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SHAH, MONIKA. "CHARACTERIZATION OF BIOLOGICALLY IMPORTANT VOLATILE AND NON-VOLATILE MOLECULES VIA HETEROATOM DETERMINATION USING CHROMATOGRAPHY AND MASS SPECTROMETRY." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1148309632.

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22

Bhogavalli, Sridhar. "Characterizatin of a Type II Metallothionein from Helianthus annuus Using Recombinant DNA Techniques." Cleveland, Ohio : Cleveland State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=csu1198989836.

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Thesis (M.S.)--Cleveland State University, 2007.
Abstract. Title from PDF t.p. (viewed on May 8, 2008). Includes bibliographical references (p. 41-45). Available online via the OhioLINK ETD Center. Also available in print.

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23

Du, Liangfen. "Characterisation of air-borne sound sources using surface coupling techniques." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI028/document.

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La thèse se base sur la recherche des possibilités de caractérisation du son aérien de sources sonores arbitraires. A cette fin, une approche particulière est étudiée à l’endroit où la caractérisation de la source est faite via une surface d’interface qui enveloppe totalement ou partiellement la source physique. Deux descripteurs qui dépendent de la fréquence sont definis au travers d’une telle surface: la pression sonore bloquée et l’impédance de la source. Le précédent représente la pression sonore créée par le système d’exploitation source qui agit sur la surface enveloppante quand elle est rendue immobile. Cette dernière représente le rapport des amplitudes de réponse de pression et les amplitudes de vitesse d’excitation normales au travers de la surface. La surface enveloppante définit un volume d’air qui contient la source physique appelée l’espace source. Les deux descripteurs définis sur l’espace source, la pression bloquée et l’impédance de la source sont montrés comme étant intrinsèques à la source, c’est-à-dire indépendants de l’espace acoustique environnant. Une fois définis, ces descripteurs permettent de trouver la pression sonore et la vitesse particulaire normale à la surface de l’interface quand l’espace source est couplé à un espace récepteur arbitraire, c’est-à-dire une pièce. Cela permet alors la prédiction du son dans l’espace récepteur. Les conditions de couplage nécessitent que l’espace récepteur soit caractérisé en utilisant la même surface enveloppante telle que l’espace source. En acceptant de garder à l’esprit la simplicité de la mesure, la surface enveloppante a été conçue vu qu’elle comporte une ou plusieurs surfaces rectangulaires planes. Le défi de la recherche était alors d’obtenir une impédance significative de la surface au travers de la surface plane rectangulaire (continue) ainsi que celle de la pression bloquée compatible avec la formulation de l’impédance. Cela a conduit à une décomposition dans l’espace de la pression sonore et de la vitesse des particules au sein du nombre fini des composants, chacun défini par une amplitude complexe et une distribution dans l’espace particulière. De cette façon, la pression bloquée se réduit à un vecteur d’amplitude de pression complexe, tandis que l’impédance devient une matrice de pression et des rapports d’amplitudes complexes de la vitesse de défauts de de décompositions ont été recherchés dans le détail: la méthode harmonique de surface et la méthode du patch. Le premier se rapproche de la pression de surface et de la vitesse normale par des combinaisons de fonctions de surface trigonométriques en 2D tandis que ce dernier partage la surface en petites parcelles et intervient sur chaque parcelle de façon discrète en utilisant les valeurs moyennes du patch
The thesis investigates possibilities of air-borne sound characterisation of arbitrary sound sources. To this end a particular approach is studied where the source characterisation is done via an interface surface which fully or partially envelopes the physical source. Two frequency dependent descriptors are defined across such a surface: the blocked sound pressure and the source impedance. The former represents the sound pressure created by the operating source which acts on the enveloping surface when this is made immobile. The latter represents the ratio of pressure response amplitudes and normal velocity excitation amplitudes across the surface. The enveloping surface defines an air volume containing the physical source, called the source space. The two source descriptors defined on the source space, the blocked pressure and the source impedance, are shown to be intrinsic to the source, i.e. independent of the surrounding acoustical space. Once defined, these descriptors allow one to find the sound pressure and normal particle velocity at the interface surface when the source space is coupled to an arbitrary receiver space, i.e. a room. This in turn allows for sound prediction in the receiver space. The coupling conditions require that the receiver space is characterised using the same enveloping surface as the source space. Bearing the measurement simplicity in mind, the enveloping surface has been conceived as consisting of one or several rectangular plane surfaces. The research challenge was then to obtain meaningful surface impedance across a (continuous) rectangular plane surface as well as the blocked pressure compatible with impedance formulation. This has led to a spatial decomposition of sound pressure and particle velocity into finite number of components, each defined by a complex amplitude and a particular spatial distribution. In this way the blocked pressure reduces to a vector of complex pressure amplitudes while the impedance becomes a matrix of pressure and velocity complex amplitude ratios. Two decomposition methods have been investigated in detail: the surface harmonic method and the patch method. The former approximates the surface pressure and normal velocity by combinations of 2D trigonometric surface functions while the latter splits the surface into small patches and treats each patch in a discrete way, using patch-averaged values

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Elbaa, Mohamed. "Caractérisation et modélisation des matériaux supraconducteurs à haute température critique." Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0196.

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L’objectif de ce travail de thèse est d’optimiser le processus d’aimantation des pastilles supraconductrices à haute température critique (SHTC) par un champ magnétique impulsionnel ou PFM (Pulsed Field Magnetization) afin de les mettre en œuvre dans des applications dans le domaine de l’électrotechnique. Dans l’étape de conception de l’inducteur nécessaire pour magnétiser ces pastilles SHTC, la modélisation et la simulation sont fortement recommandées pour effectuer les calculs nécessaires des différentes caractéristiques électriques du système d’aimantation. De ce fait, nous avons développé un modèle analytique pour étudier l’influence de la présence d’une pastille supraconductrice dans un circuit ferromagnétique sur la valeur de l’inductance d’une bobine inductrice. Il s’agit de résoudre les équations de Laplace et de Poisson dans différentes régions d’intérêt à travers le potentiel vecteur magnétique. La résolution analytique a été effectuée à l’aide d’un code de calcul développé sous MATLAB où les résultats obtenus ont été en bonne concordances avec ceux obtenus par simulation numérique sous COMSOL. L’inhomogénéité des pastilles SHTC de type YBaCuO en termes de la densité de courant critique Jc a été également étudiée. Pour cela, nous avons réalisé des expériences de l’aimantation des ces pastilles par la méthode PFM. Nous avons montré que la surface plane contenant le germe de cristallisation (seed) de ces pastilles est caractérisée par une Jc plus élevée que l’autre surface. Ainsi, nous avons étudié l’influence de la position du germe de cristallisation dans la méthode de caractérisation à deux pastilles
The aim of this thesis is to optimize the process of magnetization of superconducting pellets at high critical temperature (SHTC) by pulsed field magnetization (PFM) in order to use them in applications in the field of electrical engineering. In the design phase of the inductor necessary to magnetize these SHTC pellets, modeling and simulation are strongly recommended to perform the necessary calculations of the various electrical characteristics of the magnetization system. Therefore, we have developed an analytical model to study the influence of the presence of a superconducting bulk on the value of the inductance of an induction coil in a ferromagnetic circuit. The aim is to solve the Laplace and Poisson equations in different regions of interest through the magnetic vector potential. The analytical resolution was performed (carried out) using a computer code developed under MATLAB where the results obtained were in good agreement with those obtained by numerical simulation under COMSOL. The inhomogeneity of YBaCuO type SHTC pellets in terms of critical current density Jc was also investigated. To do this, we carried out experiments on the magnetization of these bulks by the PFM method. We have shown that the flat surface containing the crystallization germ (seed) of these pellets is characterized by a higher Jc than the other surface. Also, we studied the influence of the position of the seed crystallization in the two-pellet characterization method

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Mallek, Maryam. "Analytical methodology based on a silicone rod (SR) micro extraction combined with HPLC-DAD method for the determination of pharmaceuticals and antibacterial products in effluent wastewaters: characterization of the sorption removal processes by cork." Doctoral thesis, Universitat de Girona, 2018. http://hdl.handle.net/10803/669295.

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Solid-phase microextraction (SPME) allow the achievement of high enrichment levels by using small volumes of solvents, enabling the low detection limits required for the determination of ketoprofen, naproxen, carbamazepine, diclofenac, and triclosan in matrices of environmental interest to be obtained using HPCL-DAD. The state of art of the different SPME techniques and their latest innovations has been reviewed. An analytical method based on microextraction with polymethylsiloxane rods (PDMS) and studying the different parameters and conditions that affect the extraction stages (pH, organic modifier, ionic strength, kinetics and sample volume) and desorption (solvent, solvent volume, desorption time and sonication application). It has been shown that granulated cork can be a low-cost alternative for the elimination of PPCPs and phenolic compounds from water given that it has a high adsorption capacity towards these pollutants
Les tècniques de microextracció en fase sòlida (SPME) permeten obtentir alts factors d'enriquiment emprant petits volums de solvents fent possible que s'assoleixin els baixos límits de detecció requerits per la determinació de ketoprofen, naproxen, carbamazepina, diclofenac i triclosan en matrius d'interès ambiental emprant HPLC-DAD. S'ha revisat l'estat de l'art de les diferents tècniques de SPME i les seves darreres innovacions. S'ha desenvolupat i validat un mètode analític basat en la microextracció amb vareta polidimetilsiloxà (PDMS) i HPLC-DAD per la determinació de PPCPs, estudiant-ne els diferents paràmetres i condicions que afecten a les etapes d'extracció (pH, modificador orgànic, força iònica, cinètica i volum de mostra) i de desorció (dissolvent, volum, temps de desorció i aplicació de sonicació). S'ha demostrat que el suro granulat pot ser una alternativa de baix cost per l'eliminació de PPCPs i compostos fenòlics de les aigües atès que la seva capacitat per adsorbir aquests contaminants és alta

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Wong, Won Gina Micheline. "Selected analytical techniques in dendroanalysis." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0021/MQ58102.pdf.

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27

Hreczuk-Hirst, Dale. "Rapid analytical techniques for ondansetron." Thesis, University of Sunderland, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284754.

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28

Seetohul, L. Nitin. "Novel applications of optical analytical techniques." Thesis, Teesside University, 2009. http://hdl.handle.net/10149/117905.

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Novel applications of optical analytical techniques have been demonstrated in three general areas, namely application of broadband cavity enhanced absorption spectroscopy (BBCEAS) to the detection of liquid phase analytes, the use of total luminescence spectroscopy to discriminate between different type of teas and the development of an optical sensor to detect ammonia gas, based on the fluorescence quenching of a dye immobilised in a sol gel matrix. A simple BBCEAS setup has been developed with a view to perform sensitive visible wavelength measurements on liquid phase solutions. In the present work a simple low-cost experimental setup has been demonstrated for the measurement of the visible spectra of representative liquid-phase analytes in a 2 mm quartz cuvette placed at normal incidence to the cavity mirrors. Measurements on Ho3+ and sudan black with a white LED and the R ≥ 0.99 mirrors covered a broad wavelength range (~250 nm) and represents the largest wavelength range covered to date in a single BBCEAS experiment. The sensitivity of the technique as determined by the best αmin value was 5.1 x 10-5 cm-1 and was obtained using the R ≥ 0.99 mirrors. The best limit of detection (LOD) for the strong absorber brilliant blue-R, was approximately 620 pM. The optical setup was then optimised for the application of BBCEAS detection to an HPLC system. A 1 cm pathlength HPLC cell with a nominal volume of 70 ml was used in this study. The cavity was formed by two R ≥ 0.99 plano-concave mirrors with a bandwidth of ~ 420 – 670 nm. Two analytes rhodamine 6G and rhodamine B were chosen for separation by HPLC, as they were chemically similar species with distinctive visible spectra and would co-elute in an isocratic separation. The lowest value of amin obtained was 1.9 x 10-5 cm-1. The most significant advantage of the HPLC-BBCEAS study over previous studies arose from the recording of the absorption spectrum over a range of wavelengths. It was demonstrated that the spectral data collected could be represented as a contour plot which was useful in visualising analytes which nearly co-eluted. The LOD values for the two analytes studied indicated that the developed HPLC-BBCEAS setup was between 54 and 77 times more sensitive than a commercial HPLC system. For improved sensitivity and lower detection limits the low cost BBCEAS setup was used with a significantly longer 20 cm pathlength cell where the mirrors were in direct contact with the liquid phase analyte. This also reduced interface losses. The experiments were carried out using both R ³ 0.99 and R ³ 0.999 mirrors. The lowest αmin value obtained in this study was 2.8 x 10-7 cm-1 which is the lowest reported value to date for a liquid phase measurement, making this study the most sensitive liquid phase absorption measurement reported. The lowest LOD recorded was 4.6 pM, and was obtained for methylene blue with the R ³ 0.999 mirrors. A novel application of total luminescence spectroscopy to discriminate between different types of teas objectively was also investigated. A pattern recognition technique based on principal component analysis (PCA) was applied to the data collected and resulted in discrimination between both geographically similar and dissimilar teas. This work has shown the potential of fluorescence spectroscopy to distinguish between seven types of teas from Africa, India, Sri Lanka and Japan. Geographically similar black teas from 15 different plantation estates in Sri Lanka were also studied. The visualisation technique allowed the separation of all 11 types of teas when the first two principal components were utilised. The final part of the thesis describes the development of an optical sensor for the detection of ammonia gas. The operation of the sensor depended on the fluorescence quenching of the dye 9 amino acridine hydrochloride (9 AAH) immobilised in a sol gel matrix. It was also shown that the sensor response was not affected by the presence of acidic gases such as HCl and SO2. The final version of the sensor made use of dual channel monitoring to improve the sensitivity of the sensor. Measurements using diluted mixtures of ammonia gas in the range 5 -70 ppm showed that the response of the sensor was nonlinear, with the sensitivity increasing at lower concentrations. The measurement of the baseline noise allowed the LOD to be estimated at ~400 ppb.

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Robert, Rodolphe. "Analytical characterization of porous geomaterials." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2005. http://dx.doi.org/10.18452/15286.

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In der vorliegenden Arbeit wurden fünf typische Sedimentgesteine, zwei Sandsteine („Grès a Meules“, Fontainebleau), eine Kreide und zwei Kalksteine (Tuffeau, Vuillicin) im Hinblick auf ihre Porosität, Mineralbestand und Transporteigenschaften von Flüssigkeiten und Gasen untersucht. Das Ziel der Arbeit bestand zuerst in der Bestimmung von Standardabweichungen Strukturparameters und in der Aufklärung von Zusammenhängen zwischen den verschiedenen Messergebnissen. Mineralzusammensetzung und Transporteigenschaften Mehrere Zusammenhänge mit Hilfe von Wasser- und Quecksilberporosimetrie, Gasadsorption, Computertomographie, Licht- und Elektronmikroskopie, Wasseraufnahme- und Permeabilitätsmessungen, und mit Hilfe von Porenmodellen konnten nachgewiesen werden. Insbesondere wurde der Einfluss von Tonmineralien auf die Porenstruktur, die Permeabilität und die kapillare Wasseraufnahme nachgewiesen. Der Einfluss der Porenstrukturparameter auf die Wasser- und Gastransporteigenschaften wurde am Beispiel ausgewählter Sedimentgesteine ebenfalls nachgewiesen. Auf der Basis der experimentellen Ergebnisse wurden für die einzelnen Sedimentgesteine typische Porenmodelle entwickelt, die den Zusammenhang zwischen Porenstruktur im weitesten Sinne und den Transporteigenschaften bezüglich Wasser und Gasen wiedergeben. Ein wichtiger Aspekt der Arbeit war die Fragestellung, ob ausgewählte Sedimentgesteine als Referenz- bzw. Standardmaterialien für die Bewertung von Messverfahren oder von anderen Geomaterialien dienen können. Dazu wurden umfassende Homogenitätsuntersuchungen durchgeführt. Es zeigte sich, dass eine Gesteinsart (Vuillecin-Kalkstein) unabhängig von der Probengröße inhomogen war und daher in keinem Falle als Geo-Standard in Betracht kommen kann. Bei den anderen hier untersuchten Sedimentgesteinen wurde gefunden, dass sie für Messverfahren, die ein relativ großes Probenvolumen (> 15 cm3) benötigen (z. B. die Wasserporosimetrie oder die Kapillaraufstiegsmethode an Bohrkernen) als hinreichend homogen bezüglich des Einsatzes als mögliche Geo-Referenzmaterialien einzustufen sind. Damit könnten sie u. a. zur Entwicklung oder Überprüfung z. B. von Modellen für Transporteigenschaften von Geomaterialien oder als Untersuchungsmaterial für Ringversuche verwendet werden. Im Falle von Messverfahren, die ein kleineres Probenvolumen (weniger als 2 oder 3 cm3) voraussetzen, beispielsweise die Gasadsorption oder die Quecksilberporosimetrie, war die gefundene Homogenität aller fünf hier untersuchten Sedimentgesteine nicht mehr ausreichend, um als Kandidatenmaterial für eine Referenzmaterial-Zertifizierung zu dienen. Dies spiegelte sich deutlich in den wesentlich größeren Streuungen der Messresultate gegenüber "synthetischen" zertifizierten Referenzmaterialien für die Gasadsorption und die Hg-Porosimetrie wieder. Damit entfällt auch ein möglicher Einsatz für die Kalibrierung von Messapparaturen oder für Methodenvalidierungen.
In this study, five typical sedimentary rocks, two sandstones (Fontainebleau, “Grès à Meules”), a chalk and two limestones (tuffeau, Vuillecin) were analyzed with regards to their porous structure, mineral structure and fluid transport properties. The aim of this study was first to assess the different characteristics of the rocks regarding their variations and their inter-dependences. Relationships were established using techniques such as water and mercury porosimetry, gas adsorption, X-ray computed tomography, optical and electron microscopy, and performing gas permeability and water imbibition measurements and pore model analyses. In particular, the role of clay mineral concentrations was exposed and the porous structure parameters, on which the fluid transport properties significantly depend, were identified regarding the degree of their influence. Furthermore, new ideal pore models were schematized. These models describe the fluid transport behaviours of the rocks either for gas flow or water imbibition. The second main goal was to express if or not these geomaterials could become useful reference materials or standards. It was shown that the degrees of homogeneity of the rocks were low in comparison with any existing certified reference materials, which are industrially synthesized. For this major reason, the possibilities of the elaboration of useful reference values using the rocks were found to be restraint. For instance, it was evident that the Vuillecin limestone had a too low homogeneity degree to be reasonably used in any way as reference material. The variations of many structure parameters of the other rocks were low for big samples (over 15 cm³). In this case, standards could be elaborated using methods such as the water porosimetry or the capillary water imbibition kinetics. Such standards would be useful in the field of geomaterial research for qualitative inter-comparisons and for the control or the development of pore models applied to the analysis of fluid transport properties. For small sample volumes (generally below 2 or 3 cm³) measured using techniques such as mercury porosimetry or gas adsorption, the accuracy of the structure parameters was too low and the rocks were found to be unsuitable for elaborating reference or standard values in the aim of the calibrating instruments, testing the efficiency of apparatus or validating new methods.

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Kahoul, Asma. "Reconfigurable architecture floorplan optimisation using analytical techniques." Thesis, Imperial College London, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.550949.

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Since the invention of FPGAs in 1984, their capabilities have increased dramatically making them more speed, area, and power efficient than older reconfigurable devices. These advances were made possible by better computer aided design tools and the continuous development of algorithms used to both design the chips, and to map circuits onto them. However, current methodologies for FPGA chip design suffer from their dependence on empirical approaches which sample the design space based on intuition and heuristic techniques. As a result these empirical tools might result in good architectures but their optimality cannot be measured. This thesis argues the case for the use of analytical models in heterogeneous FPGA architecture exploration. It shows that the problem, when simplified, is amenable to formal optimisation techniques such as Integer Linear Programming (ILP). However, the simplification process may lead to inaccurate models causing uncertainty about the quality of the results. Consequently, existing accurate models such as that used in the versatile place and route (VPR) tool are used to quantify the performance of the analytical framework in comparison with traditional design methodologies. The results obtained in this thesis show that the architectures found by the ILP model are better than those found using traditional parameter sweep techniques with an average improvement of up to 15% in speed. In addition, these architectures are further improved by combining the accuracy of VPR with the efficiency of analytical techniques. This was achieved using a closed loop framework which iteratively refines the analytical model using place and route information from VPR. The results show a further average improvement of 10% and a total improvement of 25% in comparison with a parameter sweep methodology. In summary, the work carried out in this thesis shows that the ILP architecture exploration framework may not model heterogeneous architectures as accurately as current place and route tools, however, it improves on parameter sweep techniques by exploring a wider range of designs.

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Simjee, Nafeesa. "Development of microelectrode techniques for analytical measurements." Thesis, University of Warwick, 2003. http://wrap.warwick.ac.uk/2664/.

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This thesis describes the development and application of hydrodynamic modulation voltammetric (HMV) techniques coupled to ultramicroelectrodes (UMEs) that possess intrinsically high mass transport rates in quiescent solutions. This study demonstrates that the well defined convective-diffusive conditions of the microjet electrode (MJE) arrangement allows mass transport to be enhanced by almost two orders of magnitude compared to a 25 mm diameter disc-shaped UME. The MJE comprises a nozzle which is used to deliver solution to a UME surface at high velocity. Scanning electrochemical microscopy (SECM) with small UMEs has been used to image the hydrodynamics of the jet system with high precision. Variations in local mass transport for both IrCl63- and Fe(CN)64- oxidation at a range of flow rates has been observed at various positions within the impinging jet and the stagnation zone has been thoroughly characterised under a variety of experimental conditions. Agreement has been found between experiment and theory for voltammetric data recorded with the nozzle and UME aligned in the stagnation zone, for a range of viscous solutions examined. By modulating the mass transport rate to the surface of an UME, in the MJE arrangement, by the introduction of a rotating blade between the end of the nozzle and the UME, it was possible to enhance the current sensitivity of the system. Trace level detection, to 2 x 10-7 mol dm-3 IrCl63- solution, was readily facilitated. This type of HMV experiment has utilised two methods to provide the reference signal for phase-sensitive detection of the current signal, involving either a dual-disc electrode or a single UME coupled to an LED detection system. Both HMV methods have been shown to work well.

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Shams, Saleema Bashir. "Some new micro analytical techniques in biochemistry." Thesis, University of Salford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245056.

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Nigam, Atish 1981. "Analytical techniques for debugging pervasive computing environments." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/17962.

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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.
Includes bibliographical references (p. 63-65).
User level debugging of pervasive environments is important as it provides the ability to observe changes that occur in a pervasive environment and fix problems that result from these changes, especially since pervasive environments may from time to time exhibit unexpected behavior. Simple keepalive messages can not always uncover the source of this behavior because systems can be in an incorrect state while continuing to output information or respond to basic queries. The traditional approach to debugging distributed systems is to instrument the entire environment. This does not work when the environments are cobbled together from systems built around different operating systems, programming languages or platforms. With systems from such disparate backgrounds, it is hard to create a stable pervasive environment. We propose to solve this problem by requiring each system and component to provide a health metric that gives an indication of its current status. Our work has shown that, when monitored at a reasonable rate, simple and cheap metrics can reveal the cause of many problems within pervasive environments. The two metrics that will be focused on in this thesis are transmission rate and transmission data analysis. Algorithms for implementing these metrics, within the stated assumptions of pervasive environments, will be explored along with an analysis of these implementations and the results they provided. Furthermore, a system design will be described in which the tools used to analyze the metrics compose an out of bound monitoring system that retains a level of autonomy from the pervasive environment. The described system provides many advantages and additionally operates under the given assumptions regarding the resources available
(cont.) within a pervasive environment.
by Atish Nigam.
M.Eng.

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Stamatopoulos, Ioannis D. "Analytical techniques for modelling the laminated waveguide." Thesis, University of Surrey, 2003. http://epubs.surrey.ac.uk/844108/.

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This thesis is focused on a study on the dispersion formulation of the recently appeared ''laminated waveguide". In this framework a new method for the analysis of a wide variety of microwave components like posts, circular junctions or corners in rectangular waveguides is developed. This method can be used to model the posts in the laminated waveguide geometry and this was the main motivation of the present work. The method gives the impedance or admittance matrix of the microwave component by applying discrimination between the localised and accessible modes on the indirect mode matching (IMM) formulation. In all cases the method proved to be fast, very accurate and easy to implement. The application of the IMM technique to the dispersion formulation of the laminated waveguide is undertaken by implementing the Transverse Resonance Method. It is the first time that effort is paid, so that every possible polarisation of both bounded and unbounded modes is considered. In the process a new analytic solution is given for the modelling of the transverse bifurcation. Its significance relies on the the fact that the method of moments is not to be used in the analysis and thus its overall speed is increased. The total procedure is expected to be straightforward and flexible.

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Cardoso, dos Santos Josué. "Study of the dynamics around celestial bodies using analytical and semi-analytical techniques." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/155950.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Nowadays, despite the technological development experienced by science in general, a fact especially evident by the available powerful computer machines, the analytical and semi-analytical methods to study different space problems are still of great importance in the fields of astrodynamics and celestial mechanics. From the physical understanding of the motion of celestial bodies to the planing and designing of space missions, the use of mathematical models to deal with a very large number of contemporary problems plays a fundamental role in the progress of human knowledge. In this context, the present thesis presents the use of different mathematical techniques to deal with different various and current problems in astrodynamics and celestial mechanics. The studies developed throughout this work are applicable to both areas. The topics studied are the following ones: (1) The development of disturbing potentials using the double-averaging process, in order to be included in the Lagrange planetary which are numerically integrated to study features of orbits around Mercury and the Galilean moon Callisto; (2) The use of different perturbation integrals, techniques to identify and map different perturbations present in a planetary system, with focus on the analysis of systems of Giant planets with their massive moons; (3) The use of the concept of intermediary Hamiltonian and the use of a canonical transformation called elimination of the parallax, both to deal with binary systems in the context of the roto-orbital dynamics, this one as an approach of the fulltwo body problem; (4) An updated analysis of Gauss variational equations to study quasisatellite orbits around the Martian moon Phobos and with analytical predictions made after obtaining linear and averaged equations of motions. Therefore, this thesis intend not only to provide important analysis and results for each specific problem which it deals with along its pages, but also seeks to highlighting the merit and current relevance of different analytical and semi-analytical methods to be used in the fields of astrodynamics and celestial mechanics. Additionally, the author also hopes to offer an outcome of diverse interesting ideas and methods to be explored in future investigations in these research fields
Na atualidade, a despeito do desenvolvimento tecnológico experimentado pela ciência em geral, algo especialmente evidenciado por poderosas máquinas computacionais disponíveis, os métodos analíticos e semianalíticos para o estudo de diferentes problemas espaciais ainda são de grande importância nos campos de astrodinâmica e mecânica celeste. Desde a compreensão física do movimento de corpos celestes até ao planejamento e projeto de missões espaciais, o uso de modelos matemáticos para lidar com um grande número de problemas contemporâneos desempenha um papel fundamental no progresso do conhecimento humano. Neste contexto, a presente tese apresenta o uso de diferentes técnicas matemáticas para lidar com diversos e atuais problemas em astrodinâmica e mecânica celeste. Os estudos desenvolvidos ao longo deste trabalho são aplicáveis à ambas as áreas. Os tópicos estudados são os seguintes: (1) O desenvolvimento de potenciais perturbadores usando o processo de dupla média, de forma a serem incluídos nas equações planetárias de Lagrange que são integradas numericamente para estudar características de órbitas ao redor de Mercúrio e da lua galileana Calisto; (2) A utilização de diferentes integrais de perturbação, técnicas para identificar e mapear diferentes perturbações presentes em um sistema planetário, com foco na análise de sistemas de planetas gigantes com suas luas massivas; (3) A utilização do conceito de hamiltoniana intermediária e o uso de uma transformação canônica chamada eliminação da paralaxe, ambos para lidar com sistemas binários no contexto da dinâmica roto-orbital, essa sendo uma aproximação do problema completo de dois corpos; (3) Uma análise atualizada de equações variacionais de Gauss para o estudo de órbitas quasi-satélite ao redor da lua marciana Fobos e com predições analíticas realizadas após serem obtidas equações de movimento linearizadas e com média. Portanto, esta tese pretende não somente prover importantes análises e resultados para cada problema específico com os quais a mesma lida ao longo de suas páginas, mas também procura destacar o mérito e relevância atual de diferentes métodos analíticos e semianalíticos a serem utilizados nos campos de astrodinâmica e mecânica celeste. Adicionalmente, o autor também espera oferecer um produto de variadas ideias e métodos a serem explorados em futuras investigações nesses campos de pesquisa
2013/26652-4
2015/18881-9

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36

Pla, i. Vilanova Pepita. "Development of emerging analytical techniques for speciation studies." Doctoral thesis, Universitat de Lleida, 2020. http://hdl.handle.net/10803/671154.

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Aquesta tesi ofereix nous coneixements sobre el camp de les tècniques d'especiació basats en mesures de concentracions d'ions lliures. Les dues contribucions principals són: (i) la detecció de nous elements i (ii) la millora de les tècniques. La primera part es centra en la determinació electroquímica de dos elements trivalents com són l'In i el Sb. Darrerament, aquest dos elements han rebut molta atenció, a causa de les seves aplicacions creixents i dels possibles efectes en el medi ambient. Per tant, és necessari tenir tècniques analítiques adequades i fiables, per a tots dos elements. Per a l'anàlisi d'In, es van mesurar concentracions en In total i lliures en solució mitjançant dues tècniques electroanalítiques complementàries, SCP (Stripping chronopotentiometry) i AGNES (Absence of gradients and Nernstian equilibrium stripping), totes dues implementades amb el TMF/RDE (Thin mercury film/rotating disk electrode). Amb ambdues tècniques es van assolir límits de detecció nanomolars. AGNES va ser emprada per a l'estudi de la dissolució de nanopartícules In2O3, donat el seu ampli ús tecnológic. El pH i l'efecte dels lligands làbils en solució afectaven significativament la seva quantificació. També es van estudiar els avantatges d'utilitzar el TMF/RDE davant de l'HMDE (Hanging mercury drop electrode), aconseguint temps experimentals més curts fins i tot quan es determinen concentracions lliures petites. Les mesures presentades d'Sb representen la primera aplicació d'AGNES per detectar una espècie particular d'Sb(III) en una solució aquosa. L'Sb com a ió lliure és pràcticament inexistent, a causa de la seva extensa hidròlisi. Així doncs, la seva detecció es va basar en seguir les concentracions de Sb(OH)3(aq). Dues variants diferents d'AGNES es van emprar per a l'anàlisi d'Sb i van ser comparades. Mitjançant la variant AGNES-Q es van obtenir resultats acceptables, però els temps d'stripping que necessitava eren llargs. D'altra banda, AGNES-SCP resulta ser la tècnica més avantatjosa ja que va demostrar ser més ràpida i reproduïble. Aquesta prometedora metodologia obre camí per fer front a l'especiació d'Sb amb AGNES en altres sistemes i medis. La segona part d'aquesta tesi se centra en millorar l'aplicabilitat i l'eficiència de la tècnica DMT (Donnan membrane technique). Això es va dur a terme estudiant diversos canvis en la metodologia emprada, agrupades de la següent manera: variables experimentals, modificacions instrumentals i composició de l'acceptor. El primer conjunt va millorar l'eficàcia i la robustesa de la tècnica, descartant qualsevol efecte potencial de l'agitació de la mostra (donor), la temperatura del sistema i el mostreig de l'acceptor. Per la seva banda, la modificació instrumental es va basar en l'optimització de la relació superfície-volum, variacions en les dimensions de la cel·la de camp i utilitzar hollow fibres. Aquestes modificacions representen una manera simple i eficaç d'escurçar els temps experimentals. L'últim conjunt d'experiments es va basar en l'ajust de la composició de l'acceptor i es van aportar noves estratègies per superar els principals inconvenients de la tècnica DMT. Emprar concentracions d'electròlit suport més petites a l'acceptor que en la solució donor, van resultar en una reducció significativa dels temps experimentals. També es va veure pel cas contrati, on hi ha una major concentració d'electròlit de suport a l'acceptor que en el donor, és possible mesurar mostres més diluïdes.
Esta tesis ofrece nuevos conocimientos sobre el campo de las técnicas de especiación basados en medidas de concentraciones de iones libres. Las dos contribuciones principales son: (i) la detección de nuevos elementos y (ii) la mejora de las técnicas. La primera parte se centra en la determinación electroquímica de dos elementos trivalentes como son el In y el Sb. Últimamente, estos dos elementos han recibido mucha atención, debido a sus aplicaciones crecientes y los posibles efectos en el medio ambiente. Por lo tanto, es necesario tener técnicas analíticas adecuadas y fiables, para ambos elementos. Para el análisis de In, se midieron concentraciones de In total y libre en solución mediante dos técnicas electroanalíticas complementarias, SCP (Stripping chronopotentiometry) y AGNES (Absence of gradients and Nernstian equilibrium stripping), ambas implementadas con el TMF/RDE (Thin mercury film/rotating disk electrodes). Con ambas técnicas se alcanzaron límites de detección nanomolares. AGNES fue empleada para el estudio de la disolución de nanopartículas In2O3, dado su amplio uso tecnológico. El pH y el efecto de los ligandos lábiles en solución afectaban signicativamente su cuantificación. También se estudiaron las ventajas de utilizar el TMF/RDE ante el HMDE (Hanging mercury drop electrode), consiguiendo tiempos experimentales más cortos incluso cuando se determinan concentraciones libres pequeñas. Las medidas presentadas de Sb representan la primera aplicación de AGNES para detectar una especie particular de Sb(III) en una solución acuosa. El Sb como ion libre es prácticamente inexistente, debido a su extensa hidrólisis. Así pues, su detección se basó en seguir las concentraciones de Sb(OH)3(aq). Dos variantes diferentes de AGNES se emplearon para el análisis de Sb y fueron comparadas. Mediante la variante AGNES-Q se obtuvieron resultados aceptables, pero los tiempos de stripping que necesitaba eran largos. Por otra parte, AGNES-SCP resulta ser la técnica mas ventajosa, ya que demostró ser mas rápida y reproducible. Esta prometedora metodología abre camino para hacer frente a la especiación de Sb con AGNES en otros sistemas y medios. La segunda parte de esta tesis se centra en mejorar la aplicabilidad y la eficiencia de la técnica DMT (Donnan membrane technique). Esto se llevó a cabo estudiando varios cambios en la metodología empleada, agrupadas de la siguiente manera: variables experimentales, modificaciones instrumentales y composición del acceptor. El primer conjunto mejoró la eficacia y la robustez de la técnica, descartando cualquier efecto potencial de la agitación de la muestra (donor), la temperatura del sistema y el muestreo del acceptor. Por su parte, la modificación instrumental se basó en la optimización de la relación superficie-volumen, variaciones en las dimensiones de la celda de campo y la utilización de hollow fibres. Estas modificaciones representan una manera simple y eficaz de acortar los tiempos experimentales. El último conjunto de experimentos se basó en el ajuste de la composición del acceptor y se aportaron nuevas estrategias para superar los principales inconvenientes de la técnica DMT. Utilizar concentraciones de electrolito soporte más pequeñnas en el acceptor que en la solución donor, resultó en una reducción significativa de los tiempos experimentales. También se vio, por el contrario, que cuando hay una mayor concentración de electrolito de soporte en el acceptor que en el donor, es posible medir muestras más diluidas.
This thesis offers new insights for the speciation techniques field, based on the measurement of free ions concentrations. Two main contributions are: (i) the detection of novel different elements for the discipline and (ii) the improvement of the techniques. The first part focuses on the electrochemical determination of two trivalent elements such as In and Sb. Lately, both elements have received attention, because of their increasing applications and possible effects on the environment. So, appropriate and reliable analytical techniques, for both elements, are necessary. For the analysis of In, we measured total and free In concentrations in a solution using two complementary electroanalytical techniques, SCP (Stripping chronopotentiometry) and AGNES (Absence of gradients and Nernstian equilibrium stripping), both implemented with the TMF/RDE (Thin mercury film/rotating disk electrode). We achieved nanomolar limits of detection for both techniques. Also, AGNES was employed to study the dissolution of In2O3 nanoparticles, given its wide technological use. pH and the effect of the labile ligands in solution affected significantly free In quantification. We also studied the advantages of using the TMF/RDE in front of the HMDE (Hanging mercury drop electrode), achieving shorter experimental times even when determining extremely low free In concentrations. Sb measurements represent the first application of AGNES to detect one particular specie of Sb(III) in an aqueous solution. Since Sb as a free ion is practically non-existent, because of the extensive hydrolysis of the element, the detection methodology was based on following Sb(OH)3(aq) concentrations. Two different AGNES variants were studied for Sb analysis and were compared. The variant AGNES-Q yielded acceptable results but needed very long stripping times. On the other hand, a clear advantage was presented by AGNES-SCP, which demonstrated to be faster and more reproducible. This promising methodology opens the way to tackle Sb speciation with AGNES in other systems and media. The second part of this thesis focuses on improving DMT's (Donnan membrane technique) applicability and efficiency. It was performed studying a variety of modifications, based on the following sets of concepts: experimental variables, instrumental modifications, and acceptor composition. The first set improved the efficiency and robustness of the technique, ruling out any potential effect from the sample (donor) stirring, the temperature of the system, and the sampling of the acceptor. Conversely, the instrumental modification is based on optimizing the surface-to-volume ratio, modifying the dimensions of the field cell as well as employing hollow fibres. Such modifications represented to be an effective and simple way to shorten the experimental time. The last set of experiments is based on the tuning of acceptor's composition and it revealed new strategies to overcome significantly major drawbacks of the DMT technique. Lower supporting electrolyte concentrations in the acceptor than in the donor solution presented a significant reduction of the experimental times. On the other hand, higher supporting electrolyte concentrations in the acceptor than in the donor, allows to measure more diluted samples.

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37

Altun, Zeki. "New Techniques for Sample Preparation in Analytical Chemistry." Licentiate thesis, Karlstad University, Division for Chemistry, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-1374.

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Sample preparation is often a bottleneck in systems for chemical analysis. The aim of this work was to investigate and develop new techniques to address some of the shortcomings of current sample preparation methods. The goal has been to provide full automation, on-line coupling to detection systems, short sample preparation times and high-throughput.

A new technique for sample preparation that can be connected on-line to liquid chromatography (LC) and gas chromatography (GC) has been developed. Microextraction in packed syringe (MEPS) is a new solid-phase extraction (SPE) technique that is miniaturized and can be fully automated. In MEPS approximately 1 mg of sorbent material is inserted into a gas tight syringe (100-250 μL) as a plug. Sample preparation takes place on the packed bed. Evaluation of the technique was done by the determination of local anaesthetics in human plasma samples using MEPS on-line with LC and tandem mass spectrometry (MS-MS). MEPS connected to an autosampler was fully automated and clean-up of the samples took one minute. In addition, in the case of plasma samples the same plug of sorbent could be used for about 100 extractions before it was discarded.

A further aim of this work was to increase sample preparation throughput. To do that disposable pipette tips were packed with a plug of porous polymer monoliths as sample adsorbent and were then used in connection with 96-well plates and LC-MS-MS. When roscovitine in human plasma and water samples was used as model substance, a 96-plate was handled in two minutes.

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Milne, Kenneth Thallon. "An investigation into IKBS techniques for analytical spectrofluorimetry." Thesis, Heriot-Watt University, 1986. http://hdl.handle.net/10399/1078.

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39

Almeida, Joao Carlos Gomes Rocha de. "Analytical techniques for the structural evaluation of pavements." Thesis, University of Nottingham, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357095.

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Fancy, Sally-Ann. "Physical and analytical applications of ion trapping techniques." Thesis, University of Kent, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311226.

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Starkey, Jason A. "Biochemical applications of microcolumn separation techniques." [Bloomington, Ind.] : Indiana University, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3278220.

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Thesis (Ph. D.)--Indiana University, Dept. of Chemistry, 2007.
Source: Dissertation Abstracts International, Volume: 68-09, Section: B, page: 5919. Adviser: Milos V. Novotny. Title from dissertation home page (viewed May 9, 2008).

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42

Rämö, J. (Jaakko). "Hydrogen peroxide- metals- chelating agents; interactions and analytical techniques." Doctoral thesis, University of Oulu, 2003. http://urn.fi/urn:isbn:9514269756.

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Abstract Information about interactions among metals, hydrogen peroxide and chelating agents is needed to develop environmental technology and the operating efficiency of modern elemental chlorine free and total chlorine free bleaching processes. The work presented here focused on the properties of metal chelates and corrosion of titanium in an alkaline hydrogen peroxide solution. A comparative study between three rapid analysis methods, ICP-AES, XRF and ISE, was performed in pulp matrix and error sources of ISE were investigated in detail. Sensitive and selective GC methods for chelating agents ADA and NTA in water matrices were developed. Decomposition of ADA (percentage of residual 71) was observed already at the hydrogen peroxide anion level of 400 mg/l in which DTPA was more persistent (percentage of residual 94). EDTA was stable even in the hydrogen peroxide anion level of 1200 mg/l, in which its percentage of residual was 94. DTPA, EDTA and ADA were more soluble in the presence of iron and manganese than in the absence of these metals. The chelation of iron appeared to be thermodynamically limited in hydrogen peroxide bleaching conditions. Unalloyed (Grade 2) and alloyed (Grade 5) titanium corroded at the hydrogen peroxide anion level of 200 mg/l. The presence of calcium and silica inhibitors and further iron and manganese enhanced the critical hydrogen peroxide anion levels. Grade 5 was inferior to Grade 2. During rapid uniform corrosion, the potential of unalloyed titanium was under 200 mV (SHE) and lower than that of platinum. Over 90% of manganese and many other metals could be leached into aqueous phase for ICP-AES analysis using chelation or acid hydrolysis. An XRF method for manganese, iron and copper in pulp including little or no sample treatment was developed. Measuring temperature differences and atmospheric carbon dioxide were observed to be notable error sources of the ISE technique.

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Alam, Aftab. "Analytical and intelligent techniques for dynamcally [sic] secure dispatches." Connect to this title online, 2007. http://etd.lib.clemson.edu/documents/1181251728/.

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Tymis, Nikolaos. "Analytical techniques for acoustic scattering by arrays of cylinders." Thesis, Loughborough University, 2012. https://dspace.lboro.ac.uk/2134/11376.

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The problem of two-dimensional acoustic scattering of an incident plane wave by a semi-infinite lattice is solved. The problem is first considered for sound-soft cylinders whose size is small compared to the wavelength of the incident field. In this case the formulation leads to a scalar Wiener--Hopf equation, and this in turn is solved via the discrete Wiener--Hopf technique. We then deal with a more complex case which arises either by imposing Neumann boundary condition on the cylinders' surface or by increasing their radii. This gives rise to a matrix Wiener--Hopf equation, and we present a method of solution that does not require the explicit factorisation of the kernel. In both situations, a complete description of the far field is given and a conservation of energy condition is obtained. For certain sets of parameters (`pass bands'), a portion of the incident energy propagates through the lattice in the form of a Bloch wave. For other parameters (`stop bands' or `band gaps'), no such transmission is possible, and all of the incident field energy is reflected away from the lattice.

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45

McAlister, John J. "Characterisation of basaltic weathering products by modern analytical techniques." Thesis, Queen's University Belfast, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329424.

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Abdelsalam, Mamdouh Elsayed. "Development of microelectrode techniques for analytical and environmental applications." Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326794.

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Almasoud, Nagla. "Rapid classification and differentiation of bacteria by analytical techniques." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/rapid-classification-and-differentiation-of-bacteria-by-analytical-techniques(fae59630-ef83-47fe-a81b-ccd2f57e3e9e).html.

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Several traditional methods have been used to characterise bacteria, such as biochemical, morphological and molecular tests; however, these methods are time-consuming and not always reliable. Recently, modern analytical techniques have emerged as powerful tools offering high-throughput, reliable and rapid analysis in applications, such as clinical and microbiology studies. A variety of modern analytical techniques have been employed for bacterial characterisation, including matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS), liquid chromatography-mass spectrometry (LC-MS), Fourier transform infrared (FT-IR) spectroscopy and Raman spectroscopy. This thesis focused on developing a robust MALDI-TOF-MS methodology to generate mass spectra profiles for the discrimination of clinically-significant bacteria. The data generated from MALDI-TOF-MS analysis are significantly influenced by a number of experimental factors, namely instrument settings, sample preparation, the choice of matrix, matrix additives and matrix preparation as well as sample-matrix deposition methods. The need to optimise experimental variables for bacterial analysis using MALDI-TOF-MS was evident despite the increased application of this analytical tool for clinical microbiology. Experimental optimisation revealed that the choice of matrix is the most important element in MALDI-TOF-MS analysis. Based on this study, a number of different matrices were used to obtain more reproducible mass spectra to classify bacterial samples using a rapid and effective approach. Studies in this thesis indicated that sinapinic acid (SA) is the best matrix for the analysis of proteins from intact bacteria, while 6-aza-2-thiothymine (ATT) and 2,5-dihydroxybenzoic acid (DHB) produced promising results for the analysis of lipid extracts from bacteria. Analytical techniques in combination with multivariate analysis, such as principal components analysis (PCA) and principal component-discriminant function analysis (PC-DFA), were used for bacterial discrimination. Classification was initially undertaken using MALDI-TOF-MS analysis, and subsequently FT-IR spectroscopy, Raman spectroscopy and LC-MS were performed to confirm the classification results. Two main types of bacteria were used for this analysis: 34 strains from seven Bacillus and Brevibacillus species and 35 isolates from 12 Enterococcus faecium strains. The findings showed that the four analytical techniques provide clear discrimination between bacteria at these different levels. Classification of different Bacillus and Brevibacillus bacteria using MALDI-TOF-MS analysis of extracted lipids was confirmed by LC-MS data. In addition, MALDI-TOF-MS data based on extracted lipids and intact bacterial cell proteins were very similar. MALD-TOF-MS analysis of intact enterococci cells produced successful classification with 78% correct classification rate (CCR) at the strain level. FT-IR and Raman spectroscopic data produced very similar bacterial classification with CCR of 89% and 69% at the strain level, respectively. However, classification based on MALDI-TOF-MS data and that based on spectroscopic data were slightly different (Procrustes distance of 0.81, p < 0.001, at the species level). Overall, the findings in this thesis indicate the potential of MALDI-TOF-MS as a rapid, robust and reliable method for the classification of bacteria based on different bacterial preparations.

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Angel-Smith, Sarah Jane. "Characterisation of diesel injector deposits using advanced analytical techniques." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/50745/.

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Internal diesel injector deposits (IDIDs) have become a prolific issue in the last decade, increased number of incidences have occurred since the introduction of ultra-low sulfur diesel and biodiesel. The IDIDs have caused concerns for customers such as injector systems misfiring or blocking, increased emissions and fuel consumption. Interest into the origins of the deposits has steadily grown, with identified possible causes including contaminants, degraded additives, or thermal and pressure stresses of the engine. Most examples in previous studies only provide surface analysis of IDIDs, however, the surface only provides a relatively small part of the story. In order to understand how an IDID has formed the history needs to be explained, to do this the lower layers of the IDID need to be analysed. Outcomes of this research include the first example of focused ion beam and secondary ion mass spectrometry being used in combination to analyse IDIDs and clearly shows different chemical layers, demonstrating that these deposits are made up of multiple complex chemistries. Raman spectroscopy can provide graphitic content information for IDIDs giving evidence of formation however, a method to remove fluorescence from carbonaceous structures was first devised and validated in order to allow this to be performed. The jet fuel thermal oxidation test (JFTOT) has been proven to be an effective method of replicating deposits on comparison with IDIDs from failed field engines, and key chemistries have been identified for B20 biodiesel and ultra-low sulfur diesel (ULSD). This work has used existing analytical methods to understand IDIDs and found novel insights that have not been previously observed in the literature.

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Frontasyeva, M. V. "Nuclear and related analytical techniques for bio-nano- technology." Thesis, Sumy State University, 2011. http://essuir.sumdu.edu.ua/handle/123456789/20683.

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Some results from applying nuclear and related analytical techniques in medical, environmental and industrial biotechnologies are presented. In the biomedical experiments biomass from the blue-green alga Spirulina platensis (S. platensis) has been used as a matrix for the development of pharmaceutical substances containing such essential trace elements as selenium, chromium and iodine. The feasibility of target-oriented introduction of these elements into S. platensis biocomplexes retaining its protein composition and natural beneficial properties was shown. The negative influence of mercury on growth dynamics of S. platensis was observed. Detoxification of Cr and Hg by Arthrobacter globiformis 151B was demonstrated. Microbial synthesis of technologically important silver nanoparticles by the novel actinomycete strain Streptomyces glaucus 71 MD and S. platensis was characterized by a combined use of scanning electron microscopy (SEM) and epithermal neutron activation analysis (ENAA). When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/20683

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Abel, Hermione. "An analytical study of narrative techniques in Giono's Regain." Thesis, Rhodes University, 1986. http://hdl.handle.net/10962/d1002008.

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The dominant theme in Regain is that of death leading to rebirth. This dissertation attempts to explore Giono's narrative techniques within this context. No single chapter will be devoted to a specific technique; instead, the various devices used by the author are discussed as they emerge from the structure of the chapters. Justifying the field of study as defined in the "Introduction", the following three chapters outline the passage of life from death to eventual rebirth. With acknowledgement to Frank Kermode, who writes: "A concord of past, present and future three dreams which, as Augustine said, cross in our minds, as in the present of things past, the present of things present, and the present of things future" ¹, the first three chapters bear his terminology for their headings. Chapter One, "The Present of Things Past", deals with Mameche's loss of her husband and son. Chapter Two, "The Present of Things Present", focuses upon Mameche' s realization of Gaubert's departure, and the decision that she must do something to save the dying village of Aubignane. Chapter Three, "The Present of Things Future", sees Mameche setting out in search of a wife for Panturle, and succeeding. This brings to an end Part One of the novel. Interwoven throughout the chapters are paradigms from Greek mythology, rich in universal symbolism, and the author's belief in man's ability to fuse himself with his surroundings. The conclusion summarizes the findings of this study, attempting to show how an analysis of Giono's narrative technique provides an insight into such a novel as Regain. ¹The Sense of an Ending (London: Oxford University Press, 1966), rpt., 1970, p. 50.

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Dissertations / Theses on the topic 'Characterization and analytical techniques'

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