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1
Cox, A. "Calculation of third order elastic constants and photoelastic constants of alkali halides, and heat of formation and lattice parameter of binary alkali solid solutions." Thesis, University of Reading, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374033.
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Griffiths, Catherine Ruth. "Theoretical studies of potential energy functions." Thesis, University of Sussex, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285349.
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Sage, R. P. "Alkali rock complexes - carbonatites of Northern Ontario and their economic potential." Ottawa, 1986.
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Breuer, John. "Cold elastic collisions of sodium and rubidium." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29690.
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Thesis (M. S.)--Physics, Georgia Institute of Technology, 2010.Committee Chair: Kennedy, Brian; Committee Member: Chapman, Michael; Committee Member: Zangwill, Andrew. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Byrne, Philip. "Mathematical modelling and experimental simulation of chlorate and chlor-alkali cells." Doctoral thesis, Stockholm, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3182.
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Shon, Chang Seon. "Performance-based approach to evaluate alkali-silica reaction potential of aggregate and concrete using dilatometer method." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2694.
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Zubaida, Nusrat. "Evaluation of the Potential of Residual Expansion of Concrete Affected by Alkali Aggregate Reaction." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/40581.
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One of the biggest challenges nowadays when dealing with critical AAR-affected infrastructure is to determine the induced expansion and damage attained to date in the different locations of the structure (i.e. diagnosis), to forecast its potential for further distress over time (i.e. prognosis), as well as its potential structural implications. There are a number of prognosis techniques that have been developed in the past decades which are currently being used worldwide. Yet, most of these approaches use residual expansion procedures based on accelerated laboratory tests performed on cores extracted from damaged structures. However, the majority of the results gathered from these tests have been found to be inaccurate when compared to the swelling behavior of the respective structure in the field and several potential issues have been raised with respect to the test setup and alkali leaching. This work aims to evaluate the efficiency of the various commonly used laboratory setups to assess the residual expansion of AAR-affected concrete. Three different setups (i.e.
38°C and 100% RH; 38°C and soaked in 1M NaOH and; 38°C and wrapped in 0.7M NaOH) and two types of reactive aggregates (fine and coarse) were selected for this research. Expansion is monitored over time and four damage degrees (i.e. 0.05%. 0.12%, 0.20% and 0.30%) are selected for further chemical, microscopic (DRI) and non-destructive tests. Results demonstrated that the 1 M NaOH protocol is much more aggressive than the other two setups. Furthermore, it provides the samples with a unique damage pattern that is different from field affected concrete. Finally, the proposed setup shows to be reliable in providing tested samples with similar deterioration mechanisms than expected. Yet, more efficiency in the reaction kinetics and understanding of the alkalis exchange from the system is still required.
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Potgieter, J. E. "Anorogenic alkaline ring-type complexes of the Damaraland Province, Namibia, and their economic potential." Thesis, Rhodes University, 1987. http://hdl.handle.net/10962/d1001567.
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Anorogenic alkaline ring-type complexes form within continental plate settings. Alkaline magmatism is derived from the upper mantle, in which mantle metasomatism plays an important part, as well as from partial melting of the lower crust. Radial and concentric fractures develop during the ascent of alkaline magma. Extrusion of basic and felsic magma takes place along these fractures with felsic volcanics building-up central volcanoes. As a result of emptying of the magma chamber, the superstructure of the volcano collapses and a caldera is formed. During the caldera stage syenitic and granitic material are intruded into ring fractures. Alkaline ring-type complexes may be classified as (i) alkaline qranite and syenite-type and (ii) carbonatite and undersaturated-type. These ring-type complexes occur as distinct igneous provinces. Some major provinces occur in Brazil, Corsica, Namibia, Nigeria, Norway, Saudi-Arabia and Sudan. In Namibia the Damaraland igneous province is of Mesozoic aqe and it contains 15 alkaline ring-type complexes . These complexes are situated along north-eastern trends which correspond to transform directions of the South Atlantic. During the opening of the South Atlantic (Gondwana breakup) Pan-African age lineaments were reactivated which allowed emplacement of anorogenic alkaline magmatism. A zonation of alkaline granite and syenitetype in the west and carbonatite and undersaturated-type ring-complexes in the east correlates with down- and upwarp axes parallel to the line of Gondwana fragmentation. Alkali- and H⁺-metasomatism is related to the alkaline and syenite-type whereas alkali metasomatism (fenitization) is associated with carbonatite and undersaturated-type ring-complexes. Sn, W and Ta mineralization is associated with alkaline granites of some of the alkaline granite and syenite-type ring-complexes. Fe, F, PO₄ , Nb, Th, REE, Sr, Zn and Pb mineralization is associated with carbonatite complexes. Potential exists for: (i) porphyry Cu-Mo and epithermal-type (Au, Ag, Pt-metals, base metals) mineralization in the alkaline granite and syenite-type ring-complexes and (ii) disseminated Cu, Au, Aq and Pt-metals in carbonatite and undersaturated-type ring-complexes
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Jensen, Soren Ross. "Composition and biodegradation potential of polychlorinated alkane mixtures." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82604.
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A Monte Carlo Model was developed to simulate the free-radical chlorination of n-alkanes by which polychlorinated alkane mixtures are produced. The model parameters were the relative reactivity of the hydrogen atoms on the alkane chain to chlorine free-radical substitution. The values of the parameters were determined by free-radical chlorination experiments; by interpolation of data from these experiments or from data in the literature. The result of the model is a complete characterization of the molecular composition of PCA mixtures of any carbon chain length and degree of chlorination. Properties of modeled PCA mixtures were in good agreement with properties of real PCA mixtures. This model represents the first published attempt to characterize polychlorinated alkane mixtures.The substrate specificity of oxygenolytic dehalogenase enzymes was determined. Biodegradation experiments were performed to determine what specific arrangements of chlorine atoms on n-alkane carbon chains could be acted upon by the enzymes. Terminally substituted chlorinated n-alkanes were readily dehalogenated by Pseudomonas sp.273, which expresses the enzymes. Vicinal chlorine atoms on the carbon chain could not be removed by oxygenolytic dehalogenases. By combining the results from the Monte Carlo model and the biodegradation experiments, it was possible to generate an estimate for the upper limit to aerobic biodegradation.
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Hearn, Jason Elyot. "Potentials for calcium and strontium and their application to solids and clusters." Thesis, University of Sussex, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321466.
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Baxter, George. "Synthesis of pyrolizidine alkaloid analogues as potential anti-tumour agents." Thesis, University of Glasgow, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267930.
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Armstrong, Robin Neil. "The ore forming potential of calc alkaline systems : a magmatic perspective." Thesis, University of Southampton, 1999. https://eprints.soton.ac.uk/42081/.
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The association of porphyry copper style mineralisation with extensive calc alkaline igneous activity is not in doubt. However, the role of the magmatic system in the formation of such deposits is still not fully understood. Extensive works have investigated the associated alterations, ore petrology, fluid compositions and the theoretical models of ore metal transference from magma to hydrothermal fluid. Despite these numerous studies, little or no information on the chemical composition and physical processes that occur in the magmatic system has been forthcoming. Silicate melt inclusions provide a method of directly sampling the volatile and ore metal content of magmatic systems. A study of a copperrich andesite from Hahajima, Japan, demonstrates that though the majority of calc alkaline systems have the potential to form a porphyry copper deposit, the physiochemical conditions of the magma chamber prevent most from doing so. The melt inclusions contain significant amounts of copper (up to 2000 ppm), which exceed the average andesitic melt copper content by several orders of magnitude. Measured average water content of 3.3 wt%, and a CI/H2O ratio of 0.06 from the melt inclusions are typical of those expected for an arc andesite. The analysis of samples from the Morenci and Chino porphyry copper deposits of the SW USA showed that the melt inclusions contained a maximum of c. 700 ppm Cu. By employing a fractional crystallisation model it is possible to demonstrate that melt responsible for the formation of these deposits was not an exotic copper-rich melt. However, both of these deposits displayed trace element characteristics similar to those of Adakites. A study of copper-rich quartz-included biotites from Morenci demonstrated that the parental magma of this system had a small but significant amount of crustal contamination. The copper enrichment in these biotites is the consequence of the mineral's interaction with a copper-carrying exsolved magmatic volatile phase which was in equilibrium with the melt. The quartz phenocrysts from Morenci, which host the melt inclusions and biotites have a complex history of growth and resorption. These events are faithfully recorded by the quartz's zoning. It is possible by the application of existing crystallisation models to demonstrate that during the later stages of the Morenci magma's crystallisation that a magmatic volatile phase was undergoing cycles of undersaturation, saturation and exsolution. This 'pumping' of volatiles was driven by the phenomenon of undercooling. These studies of calc-alkaline magmatic systems and their contribution to the porphyry copper-forming process, serve to provide some ground truths to the current models used to understand their formation and may provide the basis for the development of future exploration tools.
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Cadiente, Jeremy S. "Modeling and investigation of heavy oxide and alkali-halide scintillators for potential use in neutron and gamma detection systems." Thesis, Monterey, California: Naval Postgraduate School, 2015. http://hdl.handle.net/10945/45821.
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Approved for public release; distribution is unlimitedHeavy inorganic oxide and alkali-halide crystals, which previous experimental research has indicated to have fast neutron detection efficiencies well over 40%, were investigated for potential use as highly efficient gamma-neutron radiation detectors. The Monte Carlo N-Particle radiation transport code (MCNP) was used to characterize the radiation interactions in a candidate set of crystals, including Bismuth Germanate (BGO), Lead Tungstate (PWO), Cadmium Tungstate (CWO), Zinc Tungstate (ZWO), Cerium-doped Lutetium-Gadolinium Orthosilicate (LGSO:Ce), and Cerium doped Lutetium-Aluminum Garnet (LuAG:Ce). Specific detection systems proposed and studied in the laboratory were also modeled and assessed. The candidate crystal set proved to be most susceptible to energy deposition from incident gamma quanta below 0.7 MeV and above 4 MeV, most likely due to photoelectric absorption and pair production, respectively. Inelastic and elastic scattering proved to be about 98% of the total neutron interactions from a Plutonium Beryllium (PuBe) neutron source, about a fourth of which were inelastic scattering. Various components of the detector configuration were evaluated in detail. The crystal dimensions and moderation especially affected detector efficiency, which showed potential for detection efficiencies comparable to experimental data.
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Belleggia, Marco Maria. "Synthesis and characterization of artificial aggregates and their potential applications in road construction." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016.
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L’obiettivo del progetto è stato quello di realizzare ed analizzare aggregati artificiali creati attraverso geopolimerizzazione e macro-incapsulazione di paraffina in aggregati leggeri espansi, discutendo i loro possibili impieghi nelle pavimentazioni stradali. Dopo un'accurata calibrazione delle miscele geopolimeriche, sono stati realizzati degli aggregati artificiali, in seguito caratterizzati in accordo con la norma UNI EN 10343, con l'intento di sostituire materiali stradali vergini. Contemporaneamente, sono stati prodotti aggregati leggeri impregnati di paraffina (PCM), in grado di cambiare fase una volta raggiunti all'incirca i 3 °C, e successivamente rivestiti da due strati di resina poliestere e
polvere di granito, denominati PLA: sfruttandone le proprietà termiche, si è valutato il loro possibile utilizzo come soluzione anti-icing. L’ultima fase della ricerca è stata incentrata nella realizzazione di aggregati geopolimerici espansi e molto porosi che potessero contenere una elevata quantità di PCM, sostituendo l'argilla espansa utilizzata nella produzione degli PLA.
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Sadykova, Saltanat. "Electric microfield distributions and structure factors in dense plasmas." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2011. http://dx.doi.org/10.18452/16316.
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Die elektrischen Mikrofeldverteilungen (EMDs) und ihre Auswüchse wurden in einkomponentiger (OCP) Elektron-, zweikomponentigen (TCP) Elektron-Positron-, Wasserstoff- und einwertig ionisierten Alkaliplasmen im Rahmen verschiedener Pseudopotentialmodelle (PM) untersucht und mit sowohl Molekulardynamik (MD) und Monte-Carlo Simulationen als auch mit Experimenten vergliechen. Die verwendeten theoretischen Verfahren zur Berechnung von EMDs gehen zurück auf die von C. A. Iglesias entwickelte Kopplungsparameter Integrationstechnik (KPIT) für OCP und die von J. Ortner et al. vorgeschlagene verallgemeinerte KPIT für TCP. EMDs wurden im Rahmen der abgeschirmten Kelbg-, Deutsch-, Hellmann-Gurskii-Krasko(HGK)-PM untersucht, welche quantenmechanische Effekte, Abschirmungseffekte und die Struktur der Ionenrümpfe (HGK) berücksichtigen. Die Abschirmungseffekte wurden auf Grundlage der Bogoljubov-Born-Green-Kirkwood-Yvon- Methode eingeführt. Wir haben das abgeschirmte HGK-Pseudopotential in der Debye-Näherung sowie in einer mäßig gekoppelten Plasma-Näherung verwendet. Wir haben verschiedene Typen vom asymptotischen Verhalten der Verteilungsauswüchse in Abhangigheit von Plasmaparameter, Plasmatypen und Strahler bestimmt. Der Vergleich der experimentell gewonnenen Daten mit sowohl einem synthetischen Li2+-Lyman-Spektrum als auch mit einer synthetischen Li II 548 nm Linie lassen den Schluss zu, daß die EMD, welche auf der Grundlage der Iglesias-Methode für OCP im HGK-PM und der MD erhalten wurde, eine gute Übereinstimmung mit den experimentellen Werten liefert. Die statischen partiellen und Ladung-Ladung-Strukturfaktoren (SSF) wurden für Alkali- und Be2+-Plasmen unter Verwendung der von G. Gregori et al. beschriebenen Methode berechnet. Die dynamischen Strukturfaktoren (DSF) für Alkaliplasmen wurden unter Verwendung der durch V. M. Adamyan et al. entwickelten Methode der Momente berechnet. Bei beiden Methoden wurde das abgeschirmte HGK-Pseudopotential verwendet.The electric microfield distributions (EMDs) and its tails have been studied for electron one-component plasma (OCP), electron-positron, hydrogen and single-ionized alkali two-component plasmas (TCP) in a frame of different pseudopotential models (PM) and compared with Molecular Dynamics (MD) and Monte-Carlo simulations as well as with experiments. The theoretical methods used for calculation of EMDs are a coupling-parameter integration technique (CPIT) developed by C. A. Iglesias for OCP and the generalized CPIT proposed by J. Ortner et al. for TCP. We studied the EMDs in a frame of the screened Kelbg, Deutsch, Hellmann-Gurskii-Krasko (HGK) PMs which take into account quantum-mechanical, screening effects and the ion shell structure (HGK) due to the Pauli exclusion principle. The screening effects were introduced on a base of Bogoljubov-Born-Green-Kirkwood-Yvon method. We used the screened HGK pseudopotential in the Debye approximation as well as in a moderately coupled plasma approximation. The influence of the plasma coupling parameter on the EMD along with the ion shell structure was investigated. We determined different types of asymptotic behaviour of EMD tails in dependence on the plasma type, parameters and radiator. Comparison of a synthetic Li2+ Lyman spectrum as well as comparison of a synthetic Li II 548 nm line with experimental data allows us to conclude that the EMD, obtained on a base of the CPIT method for OCP within the HGK PM and MD, provides a good agreement with the experiment. We have calculated the partial and charge-charge static structure factors (SSF) for alkali and Be2+ plasmas using the method described by G. Gregori et al.. We have calculated the dynamic structure factors (DSF) for alkali plasmas using the method of moments developed by V. M. Adamyan et al. In both methods the screened HGK pseudopotential has been used.
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Hoyle, Edward R. "Factors affecting the performance of alkyl polyglucosides as potential adjuvants for agrochemicals." Thesis, University of Bristol, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264106.
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Ascott, James Richard. "Assessment of the bioremediation potential of alkane constituents of drill cuttings by extreme halophiles." Thesis, University of Exeter, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.439871.
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DeCerbo, Jennifer N. "1-Alkyl-3-Methylimidazolium bis(pentafluoroethylsulfonyl)imide Based Ionic Liquids: A Study of their Physical and Electrochemical Properties." Wright State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=wright1217963125.
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Lang, David A. King Ryan Steven. "Effects of nutrient enrichment on alkaline phosphatase activity and nitrogen fixation potential in stream periphyton." Waco, Tex. : Baylor University, 2007. http://hdl.handle.net/2104/5071.
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Ozdemir, Recep Tugrul. "Anaerobic Treatment Of Opium Alkaloid Wastewater And Effect Of Gamma-rays On Anaerobic Treatment." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607599/index.pdf.
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In this study, anaerobic treatability of opium alkaloid wastewater and the effect of radiation pretreatment (gamma-rays) on anaerobic treatability were investigated. Biochemical Methane Potential (BMP) assay was performed with alkaloid wastewater having initial COD values of 2400, 6000 and 9600 mg/L with and without basal medium (BM). The highest anaerobic treatment efficiency of 77% was obtained in the BMP reactor containing alkaloid wastewater with initial COD of 9600 mg/L and BM.
Co-substrate use was investigated by using BMP assay. Alkaloid wastewater having initial COD concentrations of 9000, 13000 and 18000 mg/L were used with glucose, acetate and glucose-acetate as co-substrates. Results revealed that co-substrate use did not improve alkaloid removal efficiency significantly but it abrogated the acclimation period of anaerobic bacteria to alkaloid wastewater.
Continuous reactor experiments were carried out in Upflow Anaerobic Sludge Blanket (UASB) reactors. Highest overall efficiencies (above 80%) were obtained in the reactor fed with co-substrate (R2) for all initial COD concentrations. Up to 78% removal efficiency was obtained in R1 (fed with alkaloid wastewater only) at initial COD concentration of 19 g/L.
Effect of radiation was sought by using BMP assay with two initial COD concentrations of 14 and 25 g/L, and two radiation doses 40 and 140 kGy. At 14 g/L COD, there was no effect of radiation on gas production for both doses. However at initial COD of 25 g/L, reactors containing wastewater dosed with 140 and 40 kGy produced gas with higher rates above certain point with respect to raw wastewater.
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Angulo-Escalante, Miguel Angel 1962. "Inhibition of thioredoxin signalling by alkyl and aryl 2-imidazolyl disulfide compounds as potential antitumor agents." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282694.
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This work describes (1) the identification of alkyl and aryl 2-imidazolyl disulfides that inhibit growth in human cancer cell lines, (2) examines the antitumor activities of these disulfides in xenografted scid mice, (3) characterizes the chemopreventive activity in min mice of the disulfides IV-2, and (4) suggests the potential mechanisms by which these compounds mediate their actions. The alkyl and aryl 2-imidazolyl disulfides are inhibitors of the TR/Trx which regulates cell growth in both normal and cancer cells and is constitutively activated in a number of human primary cancers (Berggren, 1996). We found that all of the disulfides tested were potent inhibitors of growth in a panel of 60 cancer cell lines tested by the NCI. Disulfides IV-2, VI-2, and DLK-36 were found to inhibit growth of HL-60 leukemia and MCF-breast cancer cells implanted in scid mice. However, these disulfides had no significant inhibitory effect on the growth of human HT-29 colon cancer cells implanted in scid mice. Disulfide IV-2 also demonstrated a chemopreventive activity evaluated in min mice fed diet supplemented with 250 ppm IV-2. These disulfides may function through modulation of cellular redox status. It was determined that disulfides IV-2 and DLK-36 decreased GSH levels and that this effect may be due to indirect inhibition of the TR/Trx redox system or a direct reaction of GSH with the disulfides. Importantly, Human Trx regulates transcription factors such as NF-KB and activation of this transcription factor protects cells from apoptosis. Disulfide IV-2 was observed to inhibit the transcriptional activity of NF-KB. This inhibitory activity may sensitize cells to apoptosis. Most of the disulfides tested induced apoptosis at concentrations of twice the IC50 in both MCF-7 breast and HT-20 colon cancer cells. Interestingly, a protein which is secreted by MCF-7 cells into the media can degrade disulfide IV-2. This putative molecule has a molecular weight (m.w) greater than 3000 and is likely redox sensitive because ultra-filtered conditioned media (3000 m.w.) or aged media drastically decreased the degradation or sequestration activity of conditioned media. Plasma from mice treated with disulfides IV-2 or DLK-36 (i.v.) gave the same HPLC profile as seen in in vitro studies. These disulfides could be inhibiting tumor growth by inhibition of the TR/Trx system and/or depletion of GSH. Finally, the p53 tumor suppressor protein appears to be regulated by redox conditions. Recent, evidence suggests p53 may be regulated specifically by the TR redox system. The rat embryo fibroblast cell line, Al-5, expressing wild-type p53 was less sensitive to disulfides than these same cells expressing mutant p53.
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Longchamp, Sylvie. "Oxydation électrochimique en milieu organique d'une série d'indoles aryl et alkyl substitués." Rouen, 1987. http://www.theses.fr/1987ROUES027.
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Rios, Reyes Carlos A. "Synthesis of zeolites from geological materials and industrial wastes for potential application in environmental problems." Thesis, University of Wolverhampton, 2008. http://hdl.handle.net/2436/39855.
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Zeolites are among the least-known products for environmental pollution control, separation science and technology. Due to their unique porous properties, they are used in various applications in petrochemical cracking, ion-exchange and separation and removal of gases and solvents. The preparation of synthetic zeolites from chemical reagents is expensive. Therefore, in order to reduce costs, zeolite researchers are seeking cheaper aluminosilicate bearing raw materials, such as clay minerals, to produce synthetic zeolites. This research concerns the synthesis of zeolites and zeotypes derived from low-cost materials like kaolinite (KAO), natural clinker (NC) and fly ash (FA). The motivation for using these sources as the starting materials in zeolite synthesis is driven by factors, such as they are cheap and available in bulk quantities, are currently under-utilized, have high workability, and require less water (or solution) for activation. The raw materials were activated by two different routes: (1) classic alkaline hydrothermal synthesis and (2) alkaline fusion prior to hydrothermal synthesis. In the first method, the synthesis of zeolitic materials was carried out generally in alkaline media, although KAO or its calcination product, metakaolinite (MTK), was also activated in the presence or absence of structure directing agents (SDAs) and additional silica (precipitated SiO2), with the last one determining the SiO2/Al2O3 ratio of the reaction mixture and the time given for zeolitization. Synthesis in fluoride- and calcium-bearing media was also used to activate kaolinite. The process of synthesis was optimized by applying a wide range of experimental conditions with a wide range of reaction temperature, time, mineralizer concentration and solid/solution ratio. In the second approach, an alkaline fusion step was conducted prior to hydrothermal treatment, because it plays an important role in enhancing the hydrothermal conditions for zeolite synthesis. On the other hand, this approach was adopted because it can dissolve more aluminosilicates. The main synthesis products obtained after activation of KAO in NaOH solutions included zeolite LTA (LTA), sodalite (SOD), cancrinite (CAN), faujasite (FAU), zeolite Na-P1 (GIS), JBW-type zeolite (JBW), analcime (ANA), whereas the activation of KAO in KOH solutions produced chabazite (CHA), zeolite Barrer-KF, phillipsite (PHI) and K-feldspar. The hydrothermal conversion of kaolinite in fluoride media did not produce successful results, although traces of FAU, GIS, CHA, SOD and CAN crystallized. The activation of KAO in the system CaO-SiO2-Al2O3-H2O promoted the formation of different calcium silicate hydrate (C-S-H) phases, including hydrogarnet (HYD) and tobermorite (TOB). Following the fusion approach, the main zeolitic phases obtained using NaOH as mineralizer were LTA and CAN. The main as-synthesized zeolites obtained from NC by the conventional hydrothermal treatment method include PHI, SOD and CAN. Using the fusion approach, FAU and LTA were obtained with NaOH as an activator, whereas non-zeolitic material crystallized when KOH was used. The main as-synthesized zeolitic materials obtained by hydrothermal reaction of FA include PHI, zeolite Barrer-KF, CHA and SOD with traces of TOB, ANA, zeolite LTF (LTF) and herschelite (HER), appearing occasionally. By the fusion approach, FAU was obtained with NaOH as activator, whereas no zeolitic material crystallized using KOH. Experimental results indicate that the method, mineralizer, concentration and time have strong effects on the type and degree of crystallinity of the synthesis products. On the other hand, the type and chemical composition of the as-synthesized products are strongly dependent on the chemical composition of the starting material. The chemistry of zeolite synthesis was subject to perturbations caused by the presence of impurities in the raw materials, which may remain insoluble during crystallization and cause undesired species to nucleate, developing mixtures of different types of zeolites. However, other physicochemical factors may play a very important role in the thermodynamics and kinetics of zeolite formation. The raw materials have very high contents of SiO2 and Al2O3, with SiO2/Al2O3 ratios appropriate for the synthesis of low-Si zeolitic materials with high crystallinity and cation exchange capacity (CEC). However, although zeolites’ CEC represents a very important characteristic quality in the removal of undesired species from polluted effluents, it is not the deciding factor in determining zeolite performance during ion exchange processes, since numerous other factors also need to be considered. Finally, the potential application of the raw materials and their as-synthesized products as low-cost sorbents in the remediation of metal ions and ammonium from wastewater effluents was investigated. PHI showed a lower efficiency than FAU. Selectivity of FAU for metal removal was, in decreasing order, Fe>As>Pb>Zn>Cu>Ni>Cr. Based on these results, the use of these materials has the potential to provide improved methods for the treatment of contaminated effluents.
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Vevers, William F. "Deoxynivalenol : toxicological profile and potential for reducing cereal grain contamination using bacterial additives in fermented animal feed." Thesis, University of Plymouth, 2015. http://hdl.handle.net/10026.1/4305.
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Deoxynivalenol (DON) contamination of grain destined for animal feeds is a major toxicological risk to monogastrics and is suspected of restricting productivity in ruminants. Whereas bacterial additives have been developed that can detoxify DON in the rumen and lower intestine, there are currently no commercial inoculants able to perform this task in crimped grain (CG) silage, a regionally important method of moist grain preservation based on homo- and heterofermentative lactic acid bacteria or chemical additives. Determining whether this ensiling process alongside the action of detoxifying bacteria has the potential to remove DON in CG prior to ingestion, was explored in mini-silo ensiling experiments. CG was heat treated (100 °C, 60 min) or ensiled fresh in triplicate 50 g silos, spiked with 5 mg/kg DON and inoculated with lactic acid bacteria derived from wild birds, natural epiphytic inoculants and commercially sourced silage additives (21 d). DON recovery was only significantly reduced (31.2 ± 14.4% recovery, p < 0.001, n= 30) by heat treatment, as determined by IAC-RP-HPLC-UV. Bacterial assemblage analysis by 16S rRNA PCR-DGGE-SEQ identified Weissella cibaria, Pantoea agglomerans, Bacillus subtilis, B. licheniformis and Hafnia alvei as candidate detoxification agents, of which W. cibaria and H. alvei decreased DON recovery in vitro (11.3 and 6.2% recovery respectively, p < 0.05, n = 18), which translated to inoculated W. cibaria yielding a decrease in DON recovery (67.2± 14.4%, 28 d) in naturally contaminated crimped wheat (13.5 ± 1.0 mg/kg, 35-40% moisture, p < 0.05, n =15). As W. cibaria is a lactic acid bacteria already associated with fermented CG by default it has promise as a novel DON detoxification agent in CG silage. DON is however just one of many hepatotoxic co-contaminants. Retrorsine, a DNA-crosslinking pyrrolizidine alkaloid derived from Ragwort (Senecio sp.) was investigated for interactive toxicity with DON in an in vitro co-exposure experiment. HepG2 cells were exposed to Log10 multifactorial binary exposures for 48 h followed by a suite of assays to elucidate mechanisms of interactive cytotoxicity, genotoxicity and modulation of the proteome. Retrorsine was tentatively confirmed to form DNA/protein crosslinks in the comet, micronucleus and crosslinking assays, whilst DON was found to potently induce cytotoxicity and apoptosis. Co-exposure yielded a complex toxicity response, with low doses yielding antagonistic effects and high doses trending towards additive effects, although DON dose was generally the principle component. The difficulties associated with undertaking an interactive toxicity study where both toxins have multiple metabolic and cellular targets are highlighted.
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Johansen, Jonathan Frederick. "Mathematical modelling of primary alkaline batteries." Queensland University of Technology, 2007. http://eprints.qut.edu.au/16412/.
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Three mathematical models, two of primary alkaline battery cathode discharge, and one of primary alkaline battery discharge, are developed, presented, solved and investigated in this thesis. The primary aim of this work is to improve our understanding of the complex, interrelated and nonlinear processes that occur within primary alkaline batteries during discharge. We use perturbation techniques and Laplace transforms to analyse and simplify an existing model of primary alkaline battery cathode under galvanostatic discharge. The process highlights key phenomena, and removes those phenomena that have very little effect on discharge from the model. We find that electrolyte variation within Electrolytic Manganese Dioxide (EMD) particles is negligible, but proton diffusion within EMD crystals is important. The simplification process results in a significant reduction in the number of model equations, and greatly decreases the computational overhead of the numerical simulation software. In addition, the model results based on this simplified framework compare well with available experimental data. The second model of the primary alkaline battery cathode discharge simulates step potential electrochemical spectroscopy discharges, and is used to improve our understanding of the multi-reaction nature of the reduction of EMD. We find that a single-reaction framework is able to simulate multi-reaction behaviour through the use of a nonlinear ion-ion interaction term. The third model simulates the full primary alkaline battery system, and accounts for the precipitation of zinc oxide within the separator (and other regions), and subsequent internal short circuit through this phase. It was found that an internal short circuit is created at the beginning of discharge, and this self-discharge may be exacerbated by discharging the cell intermittently. We find that using a thicker separator paper is a very effective way of minimising self-discharge behaviour. The equations describing the three models are solved numerically in MATLABR, using three pieces of numerical simulation software. They provide a flexible and powerful set of primary alkaline battery discharge prediction tools, that leverage the simplified model framework, allowing them to be easily run on a desktop PC.
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Layfield, Joshua Parker. "Theoretical studies of the dynamics of gas-phase and gas/surface atom+alkane reactions and of the structure and dynamics of water confined between hydrophobic surfaces." Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/37222.
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Comprehension of reactive chemical dynamics in the gas phase and at the gas/organic-surface interface and non-reactive dynamics at the interface between hydrophobic surfaces and water requires an understanding of the fundamental atomic and molecular interactions that undergird these important phenomena. In an effort to study these regimes of chemical interaction, we have performed computational simulations that probe the dynamics of chemical systems that exemplify each of these domains. To study gas-phase chemical dynamics, we reparametrized semiempirical Hamiltonians so that they can accurately describe the potential energy surfaces for two distinct atom+alkane reactions. In addition to their demonstrated accuracy, these methods possess the attractive quality of being computationally inexpensive enough to afford extensive direct-dynamics trajectory studies. Our results on the dynamics of atom+alkane hydrogen-abstraction reactions have shown good agreement with experimental metrics that are as diverse as product velocity distributions, excitation functions, angular distributions and rovibrational state distributions for diatomic products of the abstraction. We have demonstrated that our reparametrized Hamiltonians are suitable for investigating gas-phase reactions with up to 15 (5 heavy) atoms and that they are appropriate for studying reactions beyond the gas phase, especially gas/surface reactions.
By employing our semiempirical methods within a quantum-mechanics/molecular-mechanics hybrid scheme we are able to examine hydrogen-abstraction reactions of fluorine atoms with alkanethiolate self-assembled monolayers. Our simulations reproduce the general trends of experimental results for the cousin F+squalane reaction. Our simulations also probe the role that secondary collisions play in determining the final internal and translational energy of the product HF molecules. For instance, we determined that very few interactions with the SAM surface were required to cool rotational and translational modes of the HF product, while its vibrational energy remains unchanged on the time scale that HF molecules trap on the SAM surface.
Moving beyond the gas/organic surface interface, we have also performed molecular-dynamics simulations of thin water films confined between hydrophobic SAM surfaces. These simulations illuminated the structural and dynamics behavior induced in the water films by confinement in hydrophobic environments. While most effects of the surface do not penetrate deep into the water layers we have noted that enhanced lateral diffusion of water molecules can persist in these films with > 1 nm length scales. We have elucidated a possible mechanistic precursor for the attractive forces seen in experimental measurement of the hydrophobic effect.Ph. D.
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Sitta, Ramsey. "N-Alkyl 4-Methylamphetamine enantiomers and the implication for potential modulation of abuse liability and enhancement of psychoactive drug targeting." VCU Scholars Compass, 2017. http://scholarscompass.vcu.edu/etd/5001.
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Drugs of abuse have a long history in humanity. Currently however, a subject of great interest is the phenylalkylamine family of drugs. Not only is the abuse liability of interest but also the potential therapeutic expansion of the capabilities of this family of drugs by utilizing the unique stereospecific effects of the newly discovered hybrid compounds. Based upon prior data of N-Alkyl 4-MA the enantiomers of N-Methyl, N-Ethyl, and N-Propyl were analyzed in hDAT, hNET, and hSERT. It was found that there was a negative correlation between chain length and potency and dopaminergic component. In agreement with the currently established paradigm it was also found that in almost all cases the S(+) enantiomer was the more potent.
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Dodd, Zachary Caleb. "Petrogenesis and rare earth element economic potential of Pilot Knob, a Pliocene (?) alkaline intrusive complex in the Togwotee Pass region, northwestern Wyoming (U.S.A)." Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/20380.
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Master of ScienceGeology
Matthew E. Brueseke
Previous K-Ar dating and petrography (Obradovich, 1978) have identified Pilot Knob as an ~3.4 (±0.06) Ma alkaline intrusive body. Bulk rock geochemistry obtained via XRF from four samples of Pilot Knob verifies the transitionally alkaline composition of the body, and new REE data also show enriched La, Ce, and Nd concentrations, consistent with rare earth element (REE) enrichment. Given the increased demand for REEs over the past ~30 years and China accounting for > 90% of global REE production (Kynicky, et al. 2012), it is important to evaluate new domestic REE sources. This includes those associated with alkaline intrusive complexes, because they are demonstrated to host high REE concentrations (Verplanck and Van Gosen, 2011). Such alkaline igneous occurrences show complex mineralization and consist of many minerals containing substitutional REEs (Mariano and Mariano, 2012). This study evaluates the petrogenesis and mineralogy of Pilot Knob (and a secondary field site, Wildcat Hill) and determines whether the intrusive body is consistent with an economically viable REE deposit. Additionally, given its geographic location and Pliocene faulting and magmatism (e.g., predating the earliest volcanism at Yellowstone), Pilot Knob may represent one of the earliest structural manifestations of the “arrival” of the Yellowstone hotspot at its current location under the North American lithosphere or magmatism associated with lithospheric extension to the south at the Leucite Hills, WY. Inspection of satellite imagery, which has been verified with field data, shows that other intrusive igneous bodies (e.g. - Wildcat Hill) exist, along an apparent normal fault zone along strike with a major extensionally related fault zone documented ~10 km northwest of Pilot Knob. Clinopyroxene geobarometry, coupled with Nd isotope data (εNd[subscript 3.5Ma] = -21.9), indicates that Pilot Knob formed via a multi-stage development history that initiated with melting of ancient lithospheric mantle, where crystallization occurred at a variety of depths. As an alkaline intrusive complex, Pilot Knob has been identified, based on mineral and chemical compositions, as a kersantite, and has been found to contain approximately 600 ppm total light-rare earth element ore lode with ~150 ppm Nd, ~175 ppm La, and ~338 ppm Ce enrichment. Apatite was found to be the primary REE-bearing mineral via petrography and electron microprobe analyses. Based on current technology and processing methods, REE concentrations were not found to be significant enough to denote an economically viable REE ore deposit at Pilot Knob.
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Coons, Marc P. L. "Solvent Effects for Vertical Ionization Processes in Liquid Water and at the Liquid-Vapor Interface." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1503014629752161.
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Hepp, Johannes [Verfasser], and Michael [Akademischer Betreuer] Zech. "Beyond single biomarker-isotope studies in paleoclimatology : potential and limitations of a coupled δ²Hn-alkane-δ¹⁸Osugar paleohygrometer approach / Johannes Hepp ; Betreuer: Michael Zech." Bayreuth : Universität Bayreuth, 2019. http://d-nb.info/1200467566/34.
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Cheng, Chun-yee. "Modelling potentials, concentrations and current densities in three-dimensional electrodes for recovery of lead (II) ions from aqueous alkaline solutions by simultaneous electrodeposition of lead and lead dioxide." Thesis, Imperial College London, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436320.
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Ghrayeb, Rateb. "Caractérisation quantitative de potentiels interatomiques et de structures de dépôts métalliques par simulation de mesures de spectroscopie par diffusion d'ions alkalins dans le régime des collisions multiples." Doctoral thesis, Universite Libre de Bruxelles, 1991. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/213017.
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Laconde, Guillaume. "Conception, synthèse et évaluation pharmacologique de sulfonamides et benzoindolinothiazépines modulateurs potentiels du cycle cellulaire." Lille 2, 2002. http://www.theses.fr/2002LIL2P016.
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Sarabia, Francisco J. "Interfacial studies of Pt and Cu single-crystal electrodes modified by transition metal deposition." Doctoral thesis, Universidad de Alicante, 2021. http://hdl.handle.net/10045/118535.
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El conocimiento de las características interfaciales es de suma importancia para poder desarrollar materiales que sean capaces de dar lugar a reacciones electrocatalíticas eficientes. Por esta razón, en esta tesis se muestran diferentes estudios interfaciales sobre superficies monocristalinas de platino y cobre en diferentes electrolitos. Además se estudian las características de la interfase electrodoldisolución con superficies de platino modificadas con adátomos de hierro, cobalto y níquel. Para ello, se han empleado las técnicas de voltametría cíclica, espectroscopía infrarroja con transformada de Fourier, desplazamiento de carga con CO y salto de temperatura inducido por láser. Los resultados muestran cómo varía el campo eléctrico interfacial disminuye al aumentar el recubrimiento de hierro y níquel en la superficie de platino. Este efecto tiene un gran impacto en la reacción de evolución de hidrógeno, ya que la mejora electrocatalítica de esta reacción está relacionada con la energía de reorganización de las moléculas de agua, la cual, depende de la fortaleza del campo eléctrico interfacial. Los estudios realizados en medio alcalino para las diferentes superficies de cobre y platino sin modificar muestran una correlación entre el potencial de máxima entropía y las funciones de trabajo para cada una de las diferentes orientaciones atómicas superficiales. Por otro lado, debido a la aplicabilidad de las nanopartículas en los sistemas reales de conversión de energía, se realizaron experimentos de sincrotrón empleando la técnica de Bragg coherent difraction imaging con el objetivo de estudiar el deterioro de las nanopartículas en condiciones operando.
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Carnieletto, Renata. "Aproveitamento de energia vertida turbinável para produção de hudrogênio e geração distribuída." Universidade Federal de Santa Maria, 2011. http://repositorio.ufsm.br/handle/1/8486.
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Conselho Nacional de Desenvolvimento Científico e TecnológicoIn many hydroelectric power plants, while the water inflows are greater than demand, part of this water that could be used to generate energy is spilled by the dam gates and literally wasted. This dissertation discusses the use of this wasted hydroelectric potential for hydrogen (H2) generation through water electrolysis. The usage of this hydrogen can happen not only in vehicle engines or industrial applications, but in energy generation through fuel cells and behaving as an energy vector. The H2 production by electrolysis requires an energy source for its processing. This dissertation aims at to mitigate this issue by the use of the secondary energy. Besides the H2 generation aspects, it is presented the complete mathematic model of alkaline electrolyzers. With respect to the wasted hydroelectric potential approach it must be taken into account that alternative sources of energy are settled onto three bases: the energy source itself, the distribution grid and the interconnection energy source-to-grid (or source-to-load). Looking at this fact, the source connection and disconnection from the grid is a challenge for systems engineering. For this dissertation the simulation of Voltage Source Inverters (VSI) was selected to represent the islanded and grid tied conditions. For that, it is proposed an anti-islanding algorithm used to protect the system against faults that may occur in the grid. A reconnection algorithm is also included to obtain the synchronism of the alternative source with the electric grid. To control these inverters, two control techniques are presented along this text: DQ-frame and the proportional and resonant (P+Resonant) control. These control techniques are simulated to evaluate the application efficiency of such controllers. Additionally a smart control in perspectives of the smart grid was also developed and it is proposed in this dissertation. A smart grid integrated to the distribution system allows aggregation of efficient actions of all agents related to electricity services and so strategically making available the electricity goods and services. In this context, based on real-time spot pricing of the electricity obtained from the utility using an advanced metering device, the inverter control algorithm determines the optimal operating mode. This algorithm enables the inverter to: a) schedule local loads; b) determine either to local storage or selling of energy to the grid. Finally, it is shown that on-line fault detection in the system can also make possible a fast restoration of most contingence situations.
Em muitas Usinas Hidrelétricas, quando as afluências de água são maiores que a demanda, uma parcela desta água que ainda poderia ser utilizada para gerar energia é desviada para o vertedouro e literalmente desperdiçada. Esta energia recebe a denominação de Energia Vertida Turbinável (EVT). Essa dissertação discute o aproveitamento da EVT para produção de hidrogênio através da eletrólise da água. O uso desse hidrogênio pode ocorrer não apenas em motores de veículos ou aplicações industriais, mas na própria geração de energia elétrica em células a combustível, agindo como vetor energético. A produção de H2 por eletrólise da água convencionalmente necessita de uma fonte de energia para o processo. Essa dissertação sugere a mitigação deste problema pela utilização de energia secundária. Além de aspectos para produção de H2, é apresentada uma modelagem matemática completa de todo este processo envolvendo os eletrolisadores alcalinos. Na abordagem da EVT há que se levar em conta que as fontes alternativas em geral estão assentadas em três fundamentos: a fonte de energia, a rede de distribuição e a interconexão fonte de energia-rede (ou fonte-carga). Com vistas a este fato, a desconexão e re-conexão entre a fonte e a rede pode ser um problema desafiador para a engenharia de sistemas. Para esta dissertação, selecionou-se a simulação dos Inversores VSI (Voltage Source Inverters) como resposta para as condições de ilhamento e conexão à rede elétrica. Para isto, propõe-se um algoritmo anti-ilhamento que visa a proteção contra as faltas que possam ocorrer na rede e um algoritmo de re-conexão à rede, incluindo o meio de sincronismo da fonte alternativa com a rede. Para controlar tais inversores, duas técnicas são apresentadas ao longo deste texto: utilizando as transformações DQ e controle proporcional e ressonante (P+Resonant). Essas duas técnicas de controle são simuladas para se avaliar a eficiência da aplicação de tais controladores. Em adicional, foi desenvolvido um controle inteligente diferenciado com perspectivas ao Smart Grid. O Smart Grid integrado aos sistemas de distribuição permite agregar de forma eficiente as ações de todos os agentes ligados a ele para que, de forma estratégica, sejam disponibilizados bens e serviços de eletricidade. Neste contexto, o controle inteligente proposto para inversores de conexão com rede a utiliza técnicas de gerenciamento pelo lado da demanda e ainda determina automaticamente o ponto ótimo de operação do inversor, possibilitando assim o planejamento e arranjo de cargas locais e a determinação de quando deve ser armazenada energia ou vendida para a rede. Mostra-se finalmente que a detecção das falhas no sistema também poderá ser praticada de forma a se poder atuar rapidamente no restabelecimento das situações de contingência.
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Bláha, Vladimír. "Gelové polymerní elektrolyty pro superkondenzátory." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219207.
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This master’s thesis deals with supercapacitors and polymer gel electrolytes. The practical part deals with the preparation of samples of polymer gel electrolyte with addition of alkali salts by measuring their electrical conductivity and evaluation potential windows.
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Rossi, François-Noël. "Etude théorique des collisions non réactives entre atomes alcalins et molécules d'hydrogène ou de deuterium : Calcul et analyse des surfaces de potentiel, application aux transitions de structure fine du rubidium." Paris 13, 1986. http://www.theses.fr/1986PA132015.
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Calcul des courbes de potentiel adiabatiques pour les géométries colinéaires et perpendiculaires, à l'aide d'un pseudopotentiel dépendant du moment orbital électronique et d'une approche à deux centres; bon accord avec les calculs ab initio existants. Examen des différentes symétries de ces systèmes dans le formalisme de la théorie des groupes, afin d'étudier les valeurs propres et facteurs propres de l'hamiltonien électronique. Calcul quantique des sections efficaces relatives des transitions de structure fine de Rb induites par collision avec H(2) ou D(2). En tenant compte des niveaux rotationnels moléculaires, obtention d'un très bon accord avec les résultats expérimentaux et interprétation de l'effet isotopique
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Pokapanich, Wandared. "Solvent–Solute Interaction : Studied by Synchrotron Radiation Based Photo and Auger Electron Spectroscopies." Doctoral thesis, Uppsala universitet, Yt- och gränsskiktsvetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-138749.
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Aqueous solutions were studied using photoelectron and Auger spectroscopy, based on synchrotron radiation and a liquid micro-jet setup. By varying the photon energy in photoelectron spectra, we depth profiled an aqueous tetrabutylammonium iodide (TBAI) solution. Assuming uniform angular emission from the core levels, we found that the TBA+ ions were oriented at the surface with the hydrophobic butyl arms sticking into the liquid. We investigated the association between ions and their neighbors in aqueous solutions by studying the electronic decay after core ionization. The (2p)−1 decay of solvated K+ and Ca2+ ions was studied. The main features in the investigated decay spectra corresponded to two-hole final states localized on the ions. The spectra also showed additional features, related to delocalized two-hole final states with vacancies on a cation and a neighboring water molecule. These two processes compete, and by comparing relative intensities and using the known rate for the localized decay, we determined the time-scale for the delocalized process for the two ions. We compared to delocalized electronic decay processes in Na+, Mg2+, and Al3+, and found that they were slower in K+ and Ca2+, due to different internal decay mechanisms of the ions, as well as external differences in the ion-solute distances and interactions. In the O 1s Auger spectra of aqueous metal halide solutions, we observed features related to delocalized two-hole final states with vacancies on a water molecule and a neighboring solvated anion. The relative intensity of these feature indicated that the strength of the interaction between the halide ions and water correlated with ionic size. The delocalized decay was also used to investigate contact ion pair formation in high concentrated potassium halide solutions, but no concrete evidence of contact ion pairs was observed.Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 726
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Islam, Mohammad Saiful. "The Influence of Fibre Processing and Treatments on Hemp Fibre/Epoxy and Hemp Fibre/PLA Composites." The University of Waikato, 2008. http://hdl.handle.net/10289/2627.
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In recent years, due to growing environmental awareness, considerable attention has been given to the development and production of natural fibre reinforced polymer (both thermoset and thermoplastic) composites. The main objective of this study was to reinforce epoxy and polylactic acid (PLA) with hemp fibre to produce improved composites by optimising the fibre treatment methods, composite processing methods, and fibre/matrix interfacial bonding. An investigation was conducted to obtain a suitable fibre alkali treatment method to: (i) remove non-cellulosic fibre components such as lignin (sensitive to ultra violet (UV) radiation) and hemicelluloses (sensitive to moisture) to improve long term composites stability (ii) roughen fibre surface to obtain mechanical interlocking with matrices (iii)expose cellulose hydroxyl groups to obtain hydrogen and covalent bonding with matrices (iv) separate the fibres from their fibre bundles to make the fibre surface available for bonding with matrices (v) retain tensile strength by keeping fibre damage to a minimum level and (vi) increase crystalline cellulose by better packing of cellulose chains to enhance the thermal stability of the fibres. An empirical model was developed for fibre tensile strength (TS) obtained with different treatment conditions (different sodium hydroxide (NaOH) and sodium sulphite (Na2SO3) concentrations, treatment temperatures, and digestion times) by a partial factorial design. Upon analysis of the alkali fibre treatments by single fibre tensile testing (SFTT), scanning electron microscopy (SEM), zeta potential measurements, differential thermal analysis/thermogravimetric analysis (DTA/TGA), wide angle X-ray diffraction (WAXRD), lignin analysis and Fourier transform infrared (FTIR) spectroscopy, a treatment consisting of 5 wt% NaOH and 2 wt% Na2SO3 concentrations, with a treatment temperature of 120oC and a digestion time of 60 minutes, was found to give the best combination of the required properties. This alkali treatment produced fibres with an average TS and Young's modulus (YM) of 463 MPa and 33 GPa respectively. The fibres obtained with the optimised alkali treatment were further treated with acetic anhydride and phenyltrimethoxy silane. However, acetylated and silane treated fibres were not found to give overall performance improvement. Cure kinetics of the neat epoxy (NE) and 40 wt% untreated fibre/epoxy (UTFE) composites were studied and it was found that the addition of fibres into epoxy resin increased the reaction rate and decreased the curing time. An increase in the nucleophilic activity of the amine groups in the presence of fibres is believed to have increased the reaction rate of the fibre/epoxy resin system and hence reduced the activation energies compared to NE. The highest interfacial shear strength (IFSS) value for alkali treated fibre/epoxy (ATFE) samples was 5.2 MPa which was larger than the highest value of 2.7 MPa for UTFE samples supporting that there was a stronger interface between alkali treated fibre and epoxy resin. The best fibre/epoxy bonding was found for an epoxy to curing agent ratio of 1:1 (E1C1) followed by epoxy to curing agent ratios of 1:1.2 (E1C1.2), 1: 0.8 (E1C0.8), and finally for 1:0.6 (E1C0.6). Long and short fibre reinforced epoxy composites were produced with various processing conditions using vacuum bag and compression moulding. A 65 wt% untreated long fibre/epoxy (UTLFE) composite produced by compression moulding at 70oC with a TS of 165 MPa, YM of 17 GPa, flexural strength of 180 MPa, flexural modulus of 10.1 GPa, impact energy (IE) of 14.5 kJ/m2, and fracture toughness (KIc) of 5 MPa.m1/2 was found to be the best in contrast to the trend of increased IFSS for ATFE samples. This is considered to be due to stress concentration as a result of increased fibre/fibre contact with the increased fibre content in the ATFE composites compared to the UTFE composites. Hygrothermal ageing of 65 wt% untreated and alkali treated long and short fibre/epoxy composites (produced by curing at 70oC) showed that long fibre/epoxy composites were more resistant than short fibre/epoxy composites and ATFE composites were more resistant than UTFE composites towards hygrothermal ageing environments as revealed from diffusion coefficients and tensile, flexural, impact, fracture toughness, SEM, TGA, and WAXRD test results. Accelerated ageing of 65 wt% UTLFE and alkali treated long fibre/epoxy (ATLFE) composites (produced by curing at 70oC) showed that ATLFE composites were more resistant than UTLFE composites towards hygrothermal ageing environments as revealed from tensile, flexural, impact, KIc, SEM, TGA, WAXRD, FTIR test results. IFSS obtained with untreated fibre/PLA (UFPLA) and alkali treated fibre/PLA (ATPLA) samples showed that ATPLA samples had greater IFSS than that of UFPLA samples. The increase in the formation of hydrogen bonding and mechanical interlocking of the alkali treated fibres with PLA could be responsible for the increased IFSS for ATPLA system compared to UFPLA system. Long and short fibre reinforced PLA composites were also produced with various processing conditions using compression moulding. A 32 wt% alkali treated long fibre PLA composite produced by film stacking with a TS of 83 MPa, YM of 11 GPa, flexural strength of 143 MPa, flexural modulus of 6.5 GPa, IE of 9 kJ/m2, and KIc of 3 MPa.m1/2 was found to be the best. This could be due to the better bonding of the alkali treated fibres with PLA. The mechanical properties of this composite have been found to be the best compared to the available literature. Hygrothermal and accelerated ageing of 32 wt% untreated and alkali treated long fibre/PLA composites ATPLA composites were more resistant than UFPLA composites towards hygrothermal and accelerated ageing environments as revealed from diffusion coefficients and tensile, flexural, impact, KIc, SEM, differential scanning calorimetry (DSC), WAXRD, and FTIR results. Increased potential hydrogen bond formation and mechanical interlocking of the alkali treated fibres with PLA could be responsible for the increased resistance of the ATPLA composites. Based on the present study, it can be said that the performance of natural fibre composites largely depend on fibre properties (e.g. length and orientation), matrix properties (e.g. cure kinetics and crystallinity), fibre treatment and processing methods, and composite processing methods.
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Ayed, Othman. "Etude des interactions entre atomes alcalins (li, na, k) et monoxyde de carbone en matrices de gaz rares : analyse en spectroscopie vibrationnelle et calcul quantiques de quelques complexes." Paris 6, 1987. http://www.theses.fr/1987PA066117.
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Dans le cas de li(le plus reactif), identification de li(co)::(n), ou n = 1,2,3,4,(ou 6), avec des frequences de vibration de valence de co plus perturbees que pour les metaux de transition carbonyle,et de li::(m) co, ou m = 2,3, avec frequences nu (co) abaissees. Pour na et k, observation d'especes de haute stoechiometrie (c::(n)o::(n))**(2-) (m**(+))::(2) ou n = 2,3,4, formees apres irradiation uv-visible et correspondant a des transformations chimiques. Essai d'interpretation de ces differences de reactivite par une description quantique des agregats de plus basse stoechiometrie : dans le complexe 1 :1, les deux etats electroniques inferieurs sont l'etat **(2)sigma non liant et l'etat **(2)pi liant; la courbe de potentiel de lico possede un minimum pour li-c equiv. A 2,5 a au-dessous de la courbe de l'etat **(2)pi alors que pour naco, le minimum de la courbe pour l'etat **(2)pi est au-dessous de la courbe de l'etat **(2)sigma ; le calcul met en evidence le caractere ionique de m::(2)c::(2)o::(2) (acetylenediolate) resultant d'une reaction chimique
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Rivera, Santillan Rosa Elva. "Flottation ionique des cations métalliques par les collecteurs à longue chaîne : Application aux ions BA**(2+) et GA**(3+)." Nancy 1, 1987. http://www.theses.fr/1987NAN10241.
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Récupération du baryum à partir du milieu aqueux par flottation ionique utilisant des alkylbenzène-sulfonates de sodium. Récupération du gallium, par flottation ionique en utilisant des alkylsulfates de sodium en milieu acide, et des collecteurs à fonction oxine en milieu basique
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Bahri, Hamed. "Thermodynamique dans les milieux diphasés dispersés : cas des solutions micellaires et des microémulsions." Paris 6, 1986. http://www.theses.fr/1986PA066280.
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Déduction de relations théoriques générales liant dans les systèmes liquides diphasés, les grandeurs observables "globales" aux grandeurs "locales" dans les différentes phases. Exposé de définitions et de notions thermodynamiques. Etablissement de relations générales pour les grandeurs molaires partielles. Etudes du cas d'un système réel : bromures d'alkyltrimethylammonium en milieu eau-kcl, qui montre que les solutions micellaires en milieu salin concentré peuvent être considérées comme un système diphasé. Données sur le partage d'un soluté moléculaire aniline en milieu micellaire. Etudes des volumes molaires partiels des constituants d'une microémulsion, etc. . .
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Ildefonse, Philippe. "Analyse petrologique des alterations premeteoriques et meteoriques de deux roches basaltiques (basalte alcalin de belbex, cantal, et hawaiite de m'bouda, cameroun)." Paris 7, 1987. http://www.theses.fr/1987PA077118.
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Cette analyse permet de definir les parageneses minerales successives de l'alteration. Il est alors possible d'apprehender les mecanismes geochimiques ayant preside a ces alterations, et d'en analyser certaines relations, chronologiques ou causales, qu'ils peuvent presenter entre eux
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Oyetola, Samuel. "Synthese et etude des composes a**(i)m**(v)p::(2)o::(8) (a = k, rb, cs; m = sb, nb, mo, ta) et des acides echangeurs ioniques hm**(v)(po::(4))::(2),xh::(2)o (m = sb, ta), nouveaux types de luminophores potentiels : les phases (m'**(iii)::(1/2)m**(v)::(1/2))p::(2)o::(7) (m'=sb, bi, ln; m=sb, nb, ta)." Nantes, 1988. http://www.theses.fr/1988NANT2008.
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Premilere partie: la plupart des phases du titre ont une structure en couches voisine de celle de zrp-alpha. Le traitement en milieu acide des phases en couches km**(i)(po::(4))::(2), m=sb, ta permet d'obtenir les acides correspondant hm**(v)(po::(4))::(2)xh::(2)o. Un autre acide, hta(po::(4))::(2) 3d, peut etre obtenu directement par voie seche, description de sa structure tridimensionnelle. Determination de la teneur en eau, de la structure et du comportement thermique de ces differents acides dont la thermolyse conduit a des phases originales qui sont etudiees. Seconde partie: dans la premiere famille, les phases (m'**(iii)::(1/2)m**(v)::(3/2)) (po::(4))::(3) sont de type nasicon ou sc::(2)(no::(4))::(3) ou d'un nouveau type structural, dans la seconde, les phases m'**(iii)::(1/2)m**(v)::(1/2))p::(2)o::(7) presentent des structures voisines de celle de zrp::(2)o::(7)
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Meng-Tsung, Chiang, and 江孟宗. "Potential Energy Surface Calculations for the Collisions of an Alkali or Alkaline Earth Metal Diatomic Molecule with Carbon Containing Free Radicals." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/79612827227970242047.
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碩士中國文化大學
應用化學研究所
91
Abstract In this research, we discuss the collision reactions of Li2 + CH and Be2 + CH. The potential energy surface calculation is at the level of HF/CASSCF, in which the basis set for all atoms is cc-p VQZ. In Li2 + CH and Be2 + CH collision reactions, we calculate the PES for the 179° and 89° collision angles. For Li2 + CH, we found that both 1A’ and 1A” states are Li2(X1Σg+) + CH(X2Π) at the far distance, while 2A’ and 2A” are Li2(b3Πu) + CH(X2Π) and Li2(a3u+) +CH(X2Π), respectively. In the collision reactions of Be2 + CH, 1A’ and 1A” are ground states Be2(X1g+) + CH(X2Π), while 2A’ and 2A” states are Be2(13g) + CH(X2Π) at the far distance. We also found that 1A’ , 2A’, 1A” and 2A” can form intermediates at the near distance at both collision angles in both cases. Because the energy gaps between the excited state and the ground state intermediates are all small, so non-adiabatic transitions may take place to form the ground state product.
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Lin, Chih-Pao, and 林志寶. "The Database for Potential Alkali Reactivity of Aggregates in Taiwan." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/32482438088883974188.
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碩士國立中央大學
土木工程研究所
90
The Database for Potential Alkali Reactivity of Aggregates in Taiwan ABSTRACT The main goal of this article is to build up a database system which include data of aggregates potential reaction with alkali in Taiwan. Thus it could be reference materials to concrete constructions while the step of select good aggregates and prevent damage occurred by such reactions. Moreover , there are several advantages by using web technique to conduct the database , such as the convenience of use , the spread of this information we offer. We hope people in Taiwan could pay more attention to Alkali-Aggregate Reactions(AARs) by the establishment of this database. Although there are several methods(CNS13617 or ASTM C295 , CNS13618 or ASTM C289 , CNS13619 or ASTM C227 , ASTM C1105 , ASTM C1260 , ASTM C1293) could be used to evaluate the character of aggregate specimen in AARs , they are usually taken a lot of time to do. This situation may lead to cost raised and progress delayed on constructions. The database contain not only the test data of aggregates but also the inhibitory effects against AARs by using pozzolan materials(fly ash and slag). It could provide probable suggestions when reactive aggregates are misused. Furthermore , based on our results of the part named “supplemental investigate” in this article , we have observe an obvious change in AARs of aggregates from Nan-ao north river (E03) and Nan-ao river(E04) in ASTM C1260 and ASTM C1293. And their expansions are larger than that of andesite from coastal range(highly reactive aggregate) , aggregate from Nan-ao river especially. This kind of phenomena is unique in our results and it would be worth researching in depth. Because of they are located at metamorphic area , it is possible to find another type of reactive aggregates or injured cases. In order to prevent any damage occurred by AARs on concrete structures , we suggest to using conscientious method to research the change in AARs of aggregates from this area.
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Chien-Liang, Lai, and 賴建良. "Calculations of Potential Energy Surfaces for the Colliding Reactions of alkaline metal, alkaline-earth metal atoms with alkane, alkene, and their derivatives." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/00524691203884278323.
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碩士中國文化大學
應用化學研究所
91
In this thesis, we discuss the reactions of the excited alkaline metal atoms (Na* and Li*) colliding with methane (CH4), methyl chloride (CH3Cl), as well as the reactive potential energy surface of reaction of alkaline-earth metal (Be, 21P and Mg, 31P) with ethane (C2H4). Computations were are performed with MOLPRO 2K.2 ab initio quantum calculation software packages using the Multi-configuration Self-consistent Field (MCSCF) method. The CPU time was partially provided by National High Computing Center (NCHC) and by the work stations in our lab. The possible reaction PESs were obtained from the electrmic energy of each designed geometry in the corresponding symmetric pathways (C3V, anti-C3V, C2V), respectively. The information of PESs can help us to get insight understanding of possible intermediates and of reaction conditions. Interestingly, in the collisions of the alkaline metal atoms with alkyl halide, the energy gaps between 2A’ and 1A’ are always found to be large. This indicates a difficult pathway from crossing of different electronic states to obtain the ground state alkaline metal hydride complex. As a result, it is also interesting to discover the reaction pathway of alkaline-earth metal (Be, 21P) with ethane (C2H4). The same conclusion of large energy gap between electronic states (2A’ and 1A’) is given to yield ground state BeH as well. On the contrary, it is a possible pathway with small activation energy in the reaction of Be*+C2H4 →BeH*+C2H3.
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Yu, Tseng Chiung, and 曾瓊裕. "Potential Energy Surfaces Calculations for the Collisions of an Alkali or Alkaline Earth Metal Atom with Small Molecules or Carbon Containing Free Radicals." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/79509899147696416690.
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碩士中國文化大學
應用化學研究所
91
In this study, we reported the properties at M* + CH and M* + C2H2, where M is either an alkali（Li）or alkaline（Be）metal atom. Electronic energies along the proposed reaction coordinates have been calculated at the CASSCF level using the ROOS basis set. Li（22P） + CH（X2Π） → LiC + H and Li（22P） + CH （X2Π）→ LiH + C are both endothermic on the triplet surface in our study. For the Be（23P） + CH → BeC + H, Be 2p orbital may have a π-overlap with CH（X2Π） px or py orbital to produce a stable BeCH intermediate. For the insertion reaction of M *+ C2H2 (where M is Li or Be), the alkaline earth metal (Be) may be able to transition from 2A’ to 1A’, due to a small energy gap between them and this is an exothermic reaction. Transition between 2A’ and 1A’ is not likely to occur due to a large energy gap.
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Young, She-ho, and 楊世和. "A Study for Potential Alkali Reactivity Aggregates in East of Taiwan." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/71019567083822977110.
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碩士國立中央大學
土木工程學系
85
Aggregates in East Coast of Taiwan are abundant and extremely potentialto be mined. Meanwhile,the strength and anti- abrasion are well-accepted.But from various kinds of rocks and field observation,aggregates are consideredto be potentially deleterious as caused by alkali-aggregate reactivity. Sothis investigation is focused on aggregates in this areas from riverbeds,alluvial fans,and coasts. According to aggregates which are collected from East Cost in Taiwan,sometest methods including ASTM C-289(chemical test method for potential reactivity of aggregates),ASTM C-295(petrographic examination of aggregates for concrete)and ASTM C-227(mortar bar method for potential alkali reactivity)are carried out in this area,and to study the influences of expansion of mortar bars of the variation of alkali contents,the different sorts of immersed solution,and cyclicdrying and wetting.From a series of studies, several conclusions are obtained as follows: a)Aggregates in Hua-Tung Longitudinal Valley are almost unreactive; aggregates in Hua-Tung Coast are almost potentially reactive.The results are possibly related to geologic conditions. b)In general,if aggregates are without Pessimum expansions of mortar bars are considered to increase with the increase of total equitalent alkali content,and the expansions immersed in seawater are greater than in pure water. Therefore,seawater is proved to foment the processing of alkali- aggregatereactivity. And the most common and serious deterioration cases are precastconcrete blocks and sea defenses in sea shore.
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Wu, Hsi-Wen, and 吳璽文. "Alkali and Ultrasonic Hydrolysis to Reduce Sludge Amount and Promote Digestion Potential." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/60098455845333790498.
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碩士朝陽科技大學
環境工程與管理系碩士班
98
The main purpose of this research is to study three different hydrolysis pretreatment methods (Alkali, Ultrasonic, and Alkali with Ultrasonic)on primary sludge and waste activated sludge inside metropolitan sewage treatment plant to compare the characteristics of gas production from hydrolysis. It is hoped that the anaerobic gas produce rate can be increased through breaking solid organic materials with the hydrolysis methods. The test result discovers that by hydrolyzing primary sludge of 4% total solids with pH12,its suspended solids(SS)are decreased of 2,510 mg/L and dissolved in 3,732 mg/L of SCOD, the production of dissolved organic from each suspended solid is 1.49g SCOD/g SS. While hydrolyzing by Ultrasonic (about 0.1 kW) for 30 minutes, its SS are decreased of 3,785 mg/L and dissolved in 3,708 mg/L of SCOD, the production of dissolved organic from each suspended solid is 0.98 g SCOD/g SS. If hydrolyzing by alkali with ultrasonic for 30 minutes, its SS are decreased of 13,205 mg/L and dissolved in 16,072 mg/L of SCOD, the production of dissolved organic from each suspended solid is 1.22g SCOD/g SS. By hydrolyzing waste activated sludge with pH12 alkaline for 30 minutes, its SS are decreased of 2,985 mg/L and dissolved in 4,632 mg/L of SCOD, the production of dissolved organic from each suspended solid is 1.55g SCOD/g SS. While hydrolyzing by Ultrasonic for 30 minutes, its SS are decreased of 2,475 mg/L and dissolved in 2,948 mg/L of SCOD, the production of dissolved organic from each suspended solid is 1.19g SCOD/g SS. If hydrolyzing by alkali with Ultrasonic for 30 minutes,its SS are decreased of 14,820 mg/L and dissolved in 5,018 mg/L of SCOD, the production of dissolved organic from each suspended solid is 0.34g SCOD/g SS. From test result above, it explains that after being hydrolyzed by alkaline, the waste activated sludge performs better than primary sludge in decreasing suspended solids and SCOD dissolving. However, the primary sludge acts better in Ultrasonic hydrolysis. The alkaline with Ultrasonic hydrolysis method provides similar result of SS decreasing volume to both sludges. Yet, the waste activated sludge has browning reaction caused by damage of cell structure, its dissolute organic materials are obviously lesser than that of the primary sludge. The ammonia and phosphorus are released to water during the hydrolysis process. By hydrolyzing activated sludge of 4% total solids with NaOH adjusted to pH12, the required alkali volume is approximately 70 meq/L, the required electricity for ultrasonic hydrolysis for 30 minutes is approximately 5.5×10-2 kWh/L.