Apresentamos resultados experimentais sobre o comportamento fora de centro do íon de Cu+ em cristais de RbCl, RbBr, RbI, NaI e em cristais mistos de KI +%KCl e KCl +%KI; como também do íon de Ag+ em RbI. Usamos técnicas de absorção ótica no ultra travioleta, corrente termoestimulada (ITC) e dicroísmo induzido por pressão uniaxial. Com estas técnicas, determinamos o comportamento da força do oscilador em dependência com a temperatura, energia de ativação, tempo de relaxação em dependência com a temperatura, momento dos dipolos elétricos, a mudança de configuração do íon de Cu + na reorientação num sistema de multipoço trigonal . puro para um multipoço ortorrómbico no crital misto de KI+1%KCl. Detetamos pela primeira vez a relaxação por ativação térmica de bandas de ITC a temperatura relativamente baixa, como é o caso do íon de Ag+ em RbI que acontece em 24ºK. Ainda, apresentamos alguns resultados sobre o comportamentp do íon de Li + que fica fora de centro no KC1, em cristais de KCl contendo centros U de H- e de D-, usando absorção ótica no infravermelho médio. / Experimental results are given on the off-center behavior of Cu+ ion in RbCl, RbBr, Hbl, NaI and in mixed crystals of KI+%KCl and KCl+%KI, as also on Ag+ in RbI. We use UV optical absorption, ionic thermal current (ITC) and uniaxial stress induced dichroism techniques. It is studied the temperature dependence of the oscillator strength, the relaxation time and the electric dipo1e moment are determined in the above crystals. We observe and discuss the change on the equi1ibrium configuration trigonal of the Cu+ ion in KI to the ortorrhombic in Kl+%KCl mixed crystal. For the first time we detect with the ITC measurements a thermal activated process at low temperature (24ºK), this behaviour occurs in RbI:Ag+. Using mid-infrared absorption measurements, we give several results and discussions on the U centers (either H- or D-) perturbed by Li+ ion in KCl crystals.

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L’objet de cette thèse a été la réalisation de sondes moléculaires fluorescentes pour de la détection de césium et de potassium en milieu aqueux. Deux problématiques ont été abordées : la détection de traces de césium en vue d’applications environnementales, et la mesure de variations de potassium en milieu biologique en vue d’applications biologiques. La première partie de cette thèse concerne la détection du césium. Dans un premier temps, différentes entités complexantes du césium ont été étudiées dans le but de mesurer des concentrations de césium comprises entre 1.10-3 et 5 ppm. Certaines de ces sondes ont ensuite été utilisées au sein d’un système de mesures basé sur un circuit micro-fluidique destiné à mesurer le césium de façon continue. La seconde partie de cette thèse s’intéresse à la détection du potassium. Dont le but a été de mettre au point des sondes pour mesurer le potassium extracellulaire par imagerie de fluorescence. Une cage complexante sélective du potassium a tout d’abord été identifiée. Différentes stratégies ont ensuite été développées pour remplacer la coumarine par un fluorophore excitable à de plus hautes longueurs d’ondes. Parmi les sondes étudiées, le Calix-COU-Alcyne-Sulf a permis d’effectuer des mesures in vitro préliminaires qui ont montré que ce type de sondes ne perturbe pas l’activité neuronale et permet de détecter le potassium dans la gamme de concentration visée. / The aim of this PhD was to study fluorescent molecular sensors in order to detect cesium and potassium in aqueous media. Two different issues have been addressed: the detection of cesium traces for environmental applications, and the measure of potassium fluctuations for biological applications. The first part concerns the detection of cesium. Several complexing units were first studied, to measure cesium concentration between 1.10-3 and 5 ppm. Some of the molecules made were then used in a measuring system based on a micro-fluidic chip to measure cesium in a continuous way. The second part concerns the detection of potassium. The aim was to design sensors to measure extracellular potassium fluctuations by fluorescence imaging. A selective complexing unit was first found. Several strategies were then explored to replace a coumarin by a fluorophore excitable at higher wavelengths. Among the molecules made, the Calix-COU-Alcyne-Sulf enabled preliminary in vitro measurements and showed that this type of molecules does not affect the neuronal activity and enables to measure potassium in the range of concentration targeted.

To gain better understanding of the nature of the carbonmetal bonding in 3-neopentylallyl alkali metal (5,5-dimethyl- 2-hexenyl alkali metal) systems, an investigation is extended to 3-neopentylallylpotassium. In addition, pertinent data on the 3-neopentylallyl systems are re-examined in an attempt to understand the trends in the bonding habits, as affected by the solvent, the cation and the temperature.

The objective of the present work was to demonstrate the possibilities to reduce the emission of fine particle forming alkali during co-combustion of wood with peat in a full scale (150 kW) grate fired boiler. For this purpose the particle emissions from a 150 kW district heating grate fired boiler situated in northern part of Kramfors, Sweden, were studied. During the experiment the district heating boiler was fired with sawdust fuel with a 0, 10 and 20 wt-% (zero, low, high) peat content respectively. Mass concentrations and particle size distribution were measured by using a DLPI (13-step low-pressure cascade impactor) with a precyclone. The particle matter was analyzed for morphology and elemental composition using SEM/EDS (Scanning electron microscopy/energy dispersive spectroscopy). In addition, chemical equilibrium model calculations were used to interpret the experimental findings. The present study clearly shows that reduction of fine particles (&lt; 1 um) is possible when co-combusting wood pellets with peat pellets in grate fired boilers. When 10 wt % peat was added to the wood/peat fuel mixture the fraction of fine particles was significantly decreased (about half of that emitted during pure softwood pellet combustion). The fine particles were for all fuel types/mixtures dominated by potassium, chlorine, sulfur, sodium and zinc. The result from this work therefore shows that a significant reduction of fine particle alkali is possible when co-combusting wood pellets with peat. The results from the thermo-chemical calculations suggest that a significant share of the potassium is retained in the bottom ash as a K rich silicate slag and as KAlSi2O6(s) (Leucite) when co-combusting sawdust with peat. / <p>Validerat; 20110920 (anonymous)</p>

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.

The oxidation of thiols in petroleum is a subject of ongoing research, discussion and removal of sulfur is a topic of ongoing legislation. The Merox® process requires high pressures and temperatures. Novel catalysts and methods innovations are of interest. This work examines the synthesis, purification and use of sodium cobalt(II) tetrasulfophthalocyanine to oxidize ethanethiol to diethyl disulfide. Many systems using phthalocyanines carry out the oxidation reaction under basic conditions. This work oxidized ethanethiol to diethyl disulfide in dimethylformamide using cobalt tetrasulfophthalocyanine (CoTSPc) under alkali free conditions and was compared to cobalt sulfate heptahydrate, cobalt phthalocyanine (CoPc), FeTSPc and CuTSPc. The reaction was carried out in oxygen saturated DMF while stirring at 15, 25 and 40.00 °C. The amount of ethanethiol remaining over time was determined using Ellman's reagent. A simple GC method quantified the amount of diethyl disulfide. The reaction proceeded to completion within 10 min at 40.00 °C. A turn over number of 72 and frequency of 8.1 min−1 is obtained. The activation energy was approximately 32 kJ/mol. The prepared CoTSPc catalyst was most catalytic toward oxidation of ethanethiol followed by cobalt sulfate heptahydrate, CoPc, FeTSPc and CuTSPc was non-catalytic.

Alkali land occurs adjacent to nearly every extensively irrigated area. Much of this land is too alkaline to produce profitable crops. Each year thousands of acres or land are going out of production because or increasing alkalinity. This presents one or the most acute problem which confronts irrigation agriculture today.