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Kashani-Nejad, Sina. "Oxides in the dehydration of Magnesium Chloride Hexahydrate." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=95661.
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A novel and accurate method of chemical analysis was developed to identify and assay the products of the hydrolysis that occurred when magnesium chloride hexahydrate was heated and held at temperature and reacted with its own liberated waters of hydration. The novel method took advantage of the solubility of magnesium chloride and magnesium chloride hydrates in methanol and the concomitant insolubility of magnesium oxide and magnesium hydroxychlorides in methanol. The method was found to have a precision of 5-7 % and represents a substantial improvement over previous analytical methods. The method is also readily applied to any methanol soluble salt containing insoluble impurities, meaning that it can also be used for the monitoring of the fused salt electrolyte present the magnesium electrolysis cells. [...]Une nouvelle méthode d'analyse chimique a été développée pour identifier et tester les produits d'hydrolyse qui se forment quand le chlorure de magnésium hexahydrate est chauffé, maintenu à température constante et qu'il réagit avec les eaux d'hydratation qu'il libère. La nouvelle méthode tire avantage de la solubilité du chlorure de magnésium, hydraté ou non, et en parallèle de l'insolubilité de l'oxyde et des hydroxychlorures de magnésium dans le méthanol. Il s'avère que la méthode a montré une précision de 5-7 %, ce qui apporte une importante amélioration aux méthodes analytiques précédentes. La méthode est aussi facilement applicable a tout sel soluble, qui contiendrait des impuretés insolubles, dans le méthanol, ce qui signifie qu'elle peut aussi être utilisée pour le suivi de l'électrolyse de sel fondu présent dans les cellules d'électrolyse du magnésium. [...]
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Coscia, Carlo. "Transformation of an aluminium-iron-magnesium- chloride solution during pyrohydrolysis." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102490.
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Industrial experience has revealed that when used to treat multi-component metal chloride waste liquors, existing fluidized bed acid regeneration facilities are not as efficient as when employed for the pyrohydrolysis of conventional iron chloride solutions (i.e. waste pickle liquor). As a result, experimental studies and thermochemical modelling were performed to characterize the transformation of a saturated Al-Fe-Mg-Cl solution at 105°C, after it is injected into a reactor at 850°C. Efforts were geared toward defining the sequence of reactions that take place as the liquor gradually transforms into oxides.C, after it is injected into a reactor at 850°C. Efforts were geared toward defining the sequence of reactions that take place as the liquor gradually transforms into oxides.C, after it is injected into a reactor at 850°C. Efforts were geared toward defining the sequence of reactions that take place as the liquor gradually transforms into oxides.C, after it is injected into a reactor at 850°C. Efforts were geared toward defining the sequence of reactions that take place as the liquor gradually transforms into oxides.Upon completing a comprehensive literature review, testwork was initially performed with a simplified experimental set-up to study the physical behaviour of the chloride solution as it is exposed to a static bed of oxides at 850°C, and ultimately identify the various phases of the transformation process. Subsequently, controlled evaporative crystallization experiments were conducted under pseudo-equilibrium conditions to define the McClx·yH 2O precipitation path that takes place during the H2O evaporation phase and to determine whether the chlorides precipitate independently or as complex compounds. Further experiments were performed in a fully instrumented tube furnace to elaborate on the nature of the reactions (dehydration and/or pyrohydrolysis) that take place after all of the water in the starting solution has evaporated (i.e. T=300°C+).
In an effort to assist with the interpretation of the experimental results, thermochemical modelling was performed to predict the equilibrium phase assemblages that could occur during the transformation of the saturated Al-Fe-Mg-Cl solution, at reaction temperatures of 200°C+.
The research study at hand has shown that when the saturated Al-Fe-Mg-Cl solution at 105°C is exposed to fluidized bed pyrohydrolyzer operating conditions at 850°C, the following sequence of events take place: (1) rapid solvent H2O evaporation (i.e. vigorous boiling) and onset of solid metal chloride precipitation. (2) slurry densification due to a gradual increase in crystal content (i.e. AlCl·6H2O, FeCl2 ·xH2O, and MgCl2·xH2O, where x = 2 or 4). (3) hydrated crystal drying and onset of pyrohydrolysis (i.e. thermal decomposition of McClx·yH2O). The same holds true for the high temperature hydrolysis of typical waste pickle liquors (i.e. primarily FeCl2 solution).
The crystallization studies revealed that when the Al-Fe-Mg-Cl solution is allowed to gradually evaporate at 105°C,.AlCl3·6H 2O precipitates when 15% of the solvent water evolves from the liquor, followed by FeCl2·xH2O and MgCl2·xH 2O (where x = 2 or 4) at 26 and 41% evaporation, respectively. Ferric chloride remains in solution even after 54% of the water has been driven from the liquor. The latter result suggests that higher ferric concentrations in the reactor feed are more than likely to favour an increase in the quantity of liquor entrainment by the fluidizing gases and therefore lead to lower process efficiencies. Dedicated pyrohydrolysis experiments, with a simulated reactor atmosphere (gaseous, not dynamic), have shown that excluding kinetic effects, the transformation of the Al-Fe-Mg-Cl solution occurs primarily over the 300 to 600°C temperature range.
Thermochemical modelling revealed that with the exception of AlCl 3·6H2O hydrolysis, the majority of the reactions taking place as the saturated Al-Fe-Mg-Cl liquor is introduced into and eventually reaches 850°C are governed by either reaction kinetics or diffusion. Furthermore, the resulting phase assemblage at any given temperature was predicted to vary significantly with oxygen potential. A liquid chloride phase (including molten salt), other than the feed liquor, was not predicted to form at any temperature (i.e. 200°C or above) under the range of oxidizing or reducing conditions considered.
The findings of this research were quite useful in identifying the means for improving the performance of a commercial fluidized bed pyrohydrolyzer for a spent chloride liquor containing the said species.
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Foster, Paul J. "Continuous Co-Separation by Liquid Absorption in Aqueous Cuprous Chloride (CuCl) and Magnesium Chloride (MgCl2) Solution." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1789.pdf.
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Demirci, Gokhan. "Electrolytic Magnesium Production Using Coaxial Electrodes." Phd thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/2/12607464/index.pdf.
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Main reason for the current losses in electrolytic magnesium production is the reaction between electrode products. Present study was devoted to effective separation of chlorine gas from the electrolysis environment by a new cell design and thus reducing the extent of back reaction between magnesium and chlorine to decrease energy consumption values. The new cell design was tested by changing temperature, cathode surface, current density, anode cathode distance and electrolyte composition.
Both the voltages and the current efficiencies were considered to be influenced by the amount and hydrodynamics of chlorine bubbles in inter-electrode region. Cell voltages were also found to be affected from the nucleation of magnesium droplets and changes in electrolyte composition that took place during the electrolysis. A hydrodynamic model was used to calculate net cell voltage by including the resistance of chlorine bubbles on anode surface to theoretical decomposition voltage during electrolysis. Good correlations were obtained between experimental and calculated voltages. The same model was used to calculate current efficiencies by considering chlorine diffusion from bubble surfaces. A general agreement was obtained between calculated and experimental current efficiencies.
Desired magnesium deposition morphology and detachment characteristics from cathode were obtained when MgCl2-NaCl-KCl-CaCl2 electrolytes were employed. Current efficiencies higher than 90% could be achieved using the above electrolyte. The cell consumes around 8 kWh·
kg-1 Mg at 0.43 A&
#903
cm-2 as a result of high chlorine removal efficiency and capability of working at low inter-electrode distances. Furthermore, the cell was capable of producing magnesium with less than the lowest energy consumption industrially obtained, at about double the commonly practiced industrial current density levels.
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Jegede, Oluyemi. "Concept design of a thermo-chemical heat pump using calcium chloride-NH₃ and magnesium chloride-NH₃ working pairs." Thesis, University of Warwick, 2017. http://wrap.warwick.ac.uk/97979/.
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This work presents the design of a double effect thermochemical heat pump based on the calcium chloride-ammonia and magnesium chloride-ammonia working pairs. The work began with a comprehensive theoretical and literature review of the similar systems which exist in the literature. Once the literature review was done, a large temperature jump experimental rig was built in order to be able to determine the behaviour of the relevant working pairs. Even though the focus of the work is thermochemical reactions, the activated carbon-ammonia pair was first used to validate the large temperature jump rig. The reason for this is that the activated carbon-ammonia pair is better understood compare to the thermochemical reactions. The experiments on the activated carbon- ammonia pair yielded some useful results. The results obtained show that two heat transfer properties (thermal conductivity, k and heat transfer coefficient, h) with physical meaning can be extracted from large temperature jump data. Furthermore, the change in thermal conductivity with the packing density of the adsorbent was investigated. The general trend was one of increasing thermal conductivity as the packing density was increased, the thermal conductivity increased from 0.2Wm‾¹K‾¹ to 0.4Wm‾¹K‾¹ as the packing density was increased from 530kgm‾³ to 705kgm‾³. When the calcium chloride-ammonia and magnesium chloride-ammonia working pairs were investigated in the large temperature jump setup, the kinetic parameters for each respective reaction were obtained. This enabled the development of a dynamic model of a representative thermochemical heat pump based on the aforementioned working pairs. The dynamic model helped to investigate the performance of the heat pump under various operating conditions. The coefficient of performance (COP) and the specific heating power ranged from 1.21 to 1.40 and 40W/litre to 400W/litre respectively depending on the operating conditions.
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Lamy, Martin. "Mechanism of magnesium oxide chlorination by hydrogen chloride in a molten salt." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33977.
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The reaction of HCl gas with MgO particles suspended in a molten salt containing magnesium chloride was studied. Chlorination experiments were carried out in a batch stirred tank reactor. The determination of the MgCl2 concentration as a function of chlorination time indicated that the chlorination of MgO to MgCl2 occured through an intermediate step. The intermediate species was assumed to be MgOHCl forming according to the reaction: MgOs+HCl g→MgOHCl dAlkalimetric titration and thermal decomposition by injection of dry nitrogen were used to confirm the existence of MgOHCl in the molten salt during chlorination. Infrared spectrometry was also tentatively used to identify MgOHCl but, without success due to the hygroscopic nature of the material.
Conventional mass transfer theory was used to develop a model for the reaction of solid MgO particles with HCl dissolved in the molten salt to form MgOHCl. The model assumed shrinking particle behaviour for the MgO and was confirmed by the data from the chlorination experiments.
Moreover, experiments conducted at different HCl flow rates showed that the reaction was controlled by mass transfer of HCl dissolved in the molten salt across the liquid film surrounding the MgO particle to the surface of the particle. The following rate law was obtained CMgOCi MgO1/3=1-K nt the constant Kn was found to vary between 0.04 and 0.08 s-1 when the gas flow rate was varied from 2.5 to 7.5 SLPM at constant temperature and agitation speed of 500°C and 500 RPM, respectively.
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Hide, Nicholas John. "The production and characterisation of powder processed silver chloride electrodes for use in the magnesium-silver chloride reserve battery system." Thesis, University of Southampton, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266863.
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Jönsson, Martin. "The initial atmospheric corrosion of magnesium alloys : influence of sodium chloride and microstructure /." Stockholm, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-387.
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Pressman, A. "Electrical properties of cadmium telluride thin film solar cells activated with magnesium chloride." Thesis, University of Liverpool, 2017. http://livrepository.liverpool.ac.uk/3017359/.
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Molefe, Dan Matlhomola. "Magnesium hydroxide derivatives as stabilisers and flame retardants for plasticised poly (vinyl chloride)." Thesis, University of Pretoria, 2015. http://hdl.handle.net/2263/53529.
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The potential of magnesium hydroxide, hydromagnesite and layered double hydroxides (LDHs) as heat stabilisers and flame retardants for plasticised poly (vinylchloride) (PVC) was studied. These inorganic hydrated fillers feature flake-shaped particles with a strong tendency to agglomerate. Filler particles must be homogeneously distributed and individually dispersed in the polymer matrix in order to attain the best performance. For this reason the first step in the investigation was to explore the use of a stearic acid coating in order to improve the dispersability of these fillers in liquids. The platelet morphology-type flame retardants were coated with approximately a monolayer of stearic acid using a solvent technique. Compared to the uncoated powders, the BET surface area was lower, the powder packing density was improved, and the thickening effect on white oil was significantly reduced. The latter two observations were rationalised in terms of a reduction in the attractive interactions between the powder particles.
The viscosity of white oil slurries containing 25 wt.% solids showed shear-thinning non-Newtonian behaviour. The coated powders showed significantly lower viscosities at low shear rates although the difference diminished at high shear rates. The lower viscosities shown by the coated powders indicate that the surface modification facilitated the break-up of agglomerates and aided the dispersion of individual particles in the fluid.
The thermal decomposition of these hydrated fillers is central to their flame retardant action. At elevated temperatures they endothermically release inert gases. The latter dilute the atmosphere surrounding the burning sample while the endothermic decomposition cools the substrate. These two effects are responsible for the flame retardant action of these fillers. The detailed behaviour of the present samples was studied using thermogravimetric analysis and spectroscopic methods. The decomposition mechanisms, proposed in the literature for these flame retardants, were confirmed. This includes the mass loss, enthalpy of decomposition, and the nature of evolved gases for temperatures up to 1 000 °C. The magnesium hydroxide decomposed endothermically at temperatures well above 250 °C releasing only steam. The LDH decomposed between 225 ºC and 450 ºC and the hydromagnesite between about 220 °C and 500 °C. Both initially released water vapour followed by carbon dioxide.
Next the utility of the magnesium hydroxide, hydromagnesite and LDH as combination heat stabilisers and flame retardants for plasticised PVC was studied. Emulsion grade PVC was plasticised with 100 parts per hundred parts of resin (phr) diisononyl phthalate (DINP) and filled with 30 parts per hundred parts of resin (phr) filler additive. Thermomat static heat stabilities were determined at 200 °C by following the time dependence of hydrogen chloride evolution. Fire retardancy was studied using a cone calorimeter at a radiant flux of 35 kW m-2. The layered double hydroxide outperformed the other fillers with regard to improving heat stabilisation and also with respect to most fire retardancy indices.
Since the layered double hydroxide performed best it was decided to see whether slight composition variations could improve performance. Derivatives of the standard LDH compound ([Mg0.667Al0.333(OH)2](CO3)0.167·0.44H2O) were synthesised using a hydrothermal method. Again, emulsion grade PVC was plasticised with 100 phr diisononyl phthalate and stabilised with 30 phr of the LDH filler additive derivatives. The heat stability and fire resistance of these compounds were studied. Heat stabilities were determined at 200 °C. The dynamic heat stability tests were performed on the plastisols using the torque rheometer method. Static heat stability was evaluated on the fused compounds. It was evaluated from discoloration profiles of strips exposed for various lengths of time to high heat in a Metrastat oven. The time dependence of hydrogen chloride evolution was followed with a Metrohm Thermomat instrument. The conventional LDH provided the best dynamic heat stability. However, partial replacement of the magnesium with copper significantly delayed the release of volatile HCl. If instead the replacement was done using zinc, better colour retention was achieved.
The fire performance was determined at a radiant flux of 35 kWm?2 in a cone calorimeter. The conventional magnesium-aluminium LDH lowered the peak heat release rate of the plasticised PVC from 623 ± 8 kW m?2 to 389 ± 9 kW m?2 and reduced the smoke release by 37 %. Partial replacement of the aluminium with iron resulted in a red pigmented additive that was more effective as a flame retardant reducing the peak heat release rate (pHRR) to as little as 253 ± 5 kW m?2. This additive also showed better smoke suppression (reduction of 44 %) but the best smoke suppression was achieved by replacing part of the magnesium with copper reduction by 49 %).Thesis (PhD)--University of Pretoria, 2015.
Chemistry
PhD
Unrestricted
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Kobata, Robert Steven 1954. "AN AUTOMATED METHOD OF MEASURING ISOLATED MUSCLE CONTRACTION (VERAPAMIL, HALOTHANE, CALCIUM-CHLORIDE, MAGNESIUM SULFATE, GUINEA PIG)." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/277003.
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Bette, Sebastian. "Über basische Chloride des Nickel(II) und Magnesiums : Strukturen, Phasenbildung und Löslichkeit." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2016. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-207718.
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In der vorliegenden Arbeit wurde die Phasenbildung im ternären System Ni(OH)2-NiCl2-H2O systematisch untersucht. Die basischen Nickel(II)-chlorid Phasen NiCl(OH), Ni2Cl(OH)3, NiClx(OH)2-x, Ni3Cl2+x(OH)4-x ∙ 2 H2O mit x = 0,26; 0,48; 0,82 und Ni3Cl2+x(OH)4-x ∙ 4 H2O mit x = 0,10 konnten phasenrein hergestellt und deren Kristallstrukturen mittels hochauflösender Röntgenpulverdiffraktometrie aufgeklärt werden. Die so erhaltenen strukturellen Daten wurden durch Anwendung von IR-und Spektroskopie, UV/VIS-Spektroskopie, SQUID-Messungen, Thermoanalysen und temperaturaufgelöster in-situ Röntgenpulverdiffraktometrie als komplementäre Methoden bestätigt. Weiterhin konnte eine allgemein anwendbare Routine zur Beschreibung der Diffraktionseffekte stapelfehlerbehafteter Schichtverbindungen für das Programm TOPAS entwickelt werden. Die Bildung und Stabilität der basischen Nickel(II)-chlorid Phasen in wässriger Nickel(II)-chlorid Lösung wurde systematisch bei 200°C und 25°C über Zeiträume von zwei Jahren untersucht und Löslichkeitsdaten ermittelt.
Des Weiteren erfolgte die Untersuchung der Wechselwirkung von Magnesium Oxid und basischen Magnesiumchlorid Phasen mit wässrigen nickelhaltigen Magnesiumchlorid Lösungen. Hierbei konnte die Mischkristallbildung zwischen analogen basischen Magnesium- und Nickel(II)-chloridphasen beobachtet werden. Es wurde festgestellt, dass basische Magnesiumchloride und Magnesiumoxid ein gutes Rückhaltevermögen für gelöstes Nickel aufweisen und dass ein Zutritt von gelöstem Nickel weder die Pufferwirkung noch die Beständigkeit der basischen Magnesiumchlorid Phasen beeinträchtigt.
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Naduvath, Anu Paul. "Removal and recovery of phosphorus from side-stream hydrolysis." Thesis, KTH, Mark- och vattenteknik (flyttat 20130630), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-210715.
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The report formulates the experiments conducted to remove phosphorus from the return sludge wastewater subjected to side-stream hydrolysis. The experiments are conducted using the wastewater from the outlet of side-stream hydrolysis and is tested in a laboratory at the Duvbackens wastewater treatment plant in Gävle. Chemical precipitation is used in the experiments and displays remarkable results using magnesium chloride and calcium chloride as the precipitants. A successful removal rate of 79-99% is achieved through this method. The phosphate phosphorus content is chosen to be the criterion for estimating the phosphorus removal rate. Possible parametric variations are also reviewed in the report. The decline in ammonium nitrogen is also studied alongside. Struvite and calcium phosphate are the possible precipitates and are recovered with the prospect of recycling. Both the precipitates are known as slow fertilizers and are used in the agricultural industry. If recovered by proper means, these precipitates can reduce the pressure on phosphate industry and on naturally occurring phosphate rocks. Calcium phosphate is selected among the precipitation methods for its rapid reaction and its minimum response to parametric variations. It also expresses a faster settling property with a clear solution after precipitation. The removal and recovery of phosphorus from the side-stream hydrolysis is evaluated with a notion to operate in a pilot scale.
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Barbosa, Roberta Garcia. "FABRICAÇÃO DE SALAME TIPO HAMBURGUÊS COM SUBSTITUIÇÃO PARCIAL DE SÓDIO." Universidade Federal de Santa Maria, 2009. http://repositorio.ufsm.br/handle/1/5674.
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The excessive intake of sodium is related to hypertension and consequently to an
increased risk of cardiovascular diseases. The consumption of sodium exceeds the
nutritional recommendations in most industrialized countries. Sodium chloride is the
main source of sodium in the diet. In developed countries, meat products are one of the major sources of sodium in the form of sodium chloride. This study was aimed at
producing a Hamburg-type dry fermented sausage with low sodium levels, but keeping the traditional characteristics appreciated in this product. For this purpose, we evaluated potassium chloride and magnesium chloride as partial substitutes for sodium chloride (45, 50 and 55% substitution on mass basis). The pH, temperature,
weight loss, lactic acid bacteria counts, aerobic mesophilic bacteria counts, Salmonella, total and fecal coliforms were assessed during and after the production
of dry fermented sausages. At the end of the production the sausages were also submitted to proximate composition, mineral, water activity, objective color and sensory analyses. Results indicate that the replacement of 45 to 55% NaCl with KCl or MgCl2 yields Hamburg-type dry fermented sausages that have physico-chemical and microbiological characteristics suitable for trading. These products were within the Brazilian legal limits for moisture, protein, fat, water activity, coliforms and
Salmonella. Among the formulations developed, the highest moisture was found in MgCl2-containing sausages, which also had the lowest contents of ash and chloride.
Water activity was lower in the sausages with KCl. Although the replacement of 45% NaCl with KCl or MgCl2 have improved the sensory characteristics of Hamburg-type
dry fermented sausage, the replacement of 50% NaCl with KCl and 55% NaCl with MgCl2 also appear to be viable, since they yielded products with sensory acceptability similar to that of control.A ingestão excessiva de sódio está sendo relacionada com hipertensão e conseqüentemente com o aumento do risco de doenças cardiovasculares. O consumo de sódio excede a recomendação nutricional na maioria dos países industrializados. A principal fonte de sódio na dieta é o cloreto de sódio. Em países industrializados, os produtos cárneos são uma das principais fontes de sódio na forma de cloreto de sódio. Com o objetivo de produzir um salame tipo hamburguês com diminuição dos riscos associados ao sódio, mantendo as características já tradicionalmente apreciadas neste produto, no presente estudo avaliou-se a substituição do cloreto de sódio, em diferentes níveis (45, 50 e 55%), por cloreto de potássio e por cloreto de magnésio. Foram avaliados os parâmetros de pH, temperatura, perda de peso, contagens de bactérias ácido láticas, microrganismos mesófilos aeróbios, Salmonella, coliformes fecais e coliformes totais durante a fabricação e ao final da produção dos salames. Ao final da produção dos salames foram avaliados ainda a composição centesimal, minerais, atividade de água, cor objetiva e características sensorais. Os resultados do presente estudo indicam que a substituição de 45 a 55% do NaCl de salame tipo hamburguês por KCl ou MgCl2 (em base de massa) resulta em produtos com características físico-químicas e microbiológicas adequadas para a comercialização, permanecendo dentro dos padrões legais do Brasil para teores de umidade, proteína, gordura, atividade de água, contagens de coliformes e ausência de Salmonella. Dentre as formulações avaliadas, maior umidade foi encontrada naquelas contendo MgCl2, que também apresentaram menores valores de cinzas e cloretos. Quanto aos valores de atividade de água, estes foram menores nas formulações com KCl. Ainda que as substituições de 45% do NaCl por KCl ou MgCl2 tenham melhorado as características sensoriais do salame tipo hamburguês, as substituições de 50% do NaCl por KCl e de 55% do NaCl por MgCl2 também parecem ser viáveis, uma vez que resultaram em produtos com aceitação sensorial semelhante a do controle.
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Grimaldos, Osorio Nicolas. "Novel Ammonia Storage Materials for SCR Systems : Carbon Materials – Salt Composites." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-75167.
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The emissions of nitrogen oxides (NOx) are a serious environmental problem due to its relationship with the formation of smog, acid rain and because they are dangerous for human and animal health. These gases are produced in high quantities in diesel engines used for automotive applications, and different strategies are being used to reduce them, among which are the Selective Catalytic Reduction (SCR) systems. For its operation, it is necessary a supply of ammonia as NOx reducing agent, but the inefficiency at low temperatures of the systems used nowadays has led to the conception of the solid ammonia storage units (ASS). Unfortunately, the materials currently used, i.e. metal halides, do not meet the ammonia supply requirements at low temperatures and have problems of swelling and agglomeration. In order to find a material with better properties for its application as an ammonia sorbent material, MgCl2 composites with different carbon materials (graphite, graphene, and SWCNTs) were prepared by direct mixing and wet impregnation methods, and characterized in this work. Despite the decrease of total storage capacity, improvements were found in thermal stability and mass retention, as well as in sorption and desorption kinetics, making these materials a first result towards the improvement of the solid ammonia storage units.
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Fernandez, Joseph Rogelio. "Stress Corrosion Cracking Evaluation of Candidate High Strength Stainless Steels for Prestressed Concrete." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3102.
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Prestressed concrete piles are commonly used to support over-water highway bridges in marine environments. The reinforcing steel within will ultimately be degraded via corrosion damage due to the penetration of chloride ions from sea water. The service life of these structures is, in part, dictated by the time required to diffuse chloride ions through the concrete cover and subsequently corrode the steel. Therefore, by slowing the rate of diffusion or increasing the chloride threshold of the steel (or both) an increased service life can be expected. This thesis focuses on the latter whereby stainless steel reinforcing alternatives were investigated to elevate the chloride threshold before corrosion begins.
The designation "stainless" steel implies corrosion resistance. However, corrosion resistance in itself is not a sufficient condition to make it a suitable alternative for prestressed concrete applications. In this study, the corrosion susceptibility of stainless steel alloys was scrutinized with the understanding that high strength stainless steels are vulnerable to stress corrosion cracking (SCC). This investigation screened three candidate alloys that span the norms of stainless steel compositions: a common austenitic stainless steel with high nickel content (316L), a less common austenitic stainless steel with low nickel but high manganese (XM 29), and a duplex stainless steel with high chromium and an additional constituent, molybdenum (2205). Each alloy was subjected to two stress conditions imposed by varied mechanical fixtures then subjected to various forms of high chloride concentrations. The pH of these conditions was also varied and in one case simulated the high pH common to concrete pore water solutions. Elevated temperatures were used to accelerate the effects of these exposures.
Results of Phase 1 showed that for exposure at 135oC (275oF) cracking of alloys 316 L and 2205 occurred after 1 hour while XM29 experience cracking after 24 hours. At 90oC (194oF) alloy 316L cracked after 4 hours; XM29 did not crack after 96 hours while 2205 did crack after 96 hours. The results were interpreted with an Arrhenius relationship between time to cracking and test temperature to extrapolate toward the anticipated service regime. Results of Phase 2 showed that SCC was less likely to initiate in high pH conditions than in low pH conditions at typical marine environment temperatures and chloride concentration. In these limited tests the SCC performance of XM29 was better relative to that of the other two alloys.
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Albuquerque, Liana Filgueira. "Aplica??o da ?gua residu?ria das salinas no tratamento de efluente t?xtil." Universidade Federal do Rio Grande do Norte, 2009. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15885.
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Previous issue date: 2009-04-03Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
The treatment of colored and alkaline effluent has been a challenge to the textile industry. An alternative to remove the colors of those effluents is applying magnesium chloride as a coagulant agent. The magnesium ion, in high pH, hydrolyzes itself, forming the magnesium hydroxide which has a large adsorptive area and positive electrostatic charges able to act as an efficient coagulant. The bittern wastewater from the salt industries has been studied as a potential font of this magnesium ion. Nowadays, this bittern wastewater is evicted into the sea, without any treatment or other use. This thesis has evaluated the potential of applying the wastewater from the salt industries in the treatment of dyeing effluent containing indigo dye and alkaline pH. All the experiments were made in jar tests simulating the chemical coagulation, flocculation and decantation steps ranging the pH and the concentration of magnesium ion. Were obtained removals between 96% and 76% for turbidity, apparent color, and true color, respectively, using 200mg/L Mg2+. The reduction of costs with acid, when were used the salt industries wastewater, comparing with Al2(SO4)3, was 62%. For the degradation of organic matter remaining in the clarified, around 900 mg/L, was applyed the advanced process of oxidation: photo-Fenton. The preliminary results showed 57% reduction in DOC. According to the results obtained, the salt industries wastewater can be applied, as coagulant, in the physical-chemical treatment of the denim dyeing wastewater, so it is not necessary a previous adjust of pH, efficiently and economically
O tratamento de efluentes coloridos e alcalinos tem sido um desafio para as ind?strias t?xteis. Uma alternativa para a remo??o de cor destes efluentes ? a aplica??o do cloreto magn?sio como coagulante. O ?on magn?sio, em pH elevado, se hidrolisa, formando o hidr?xido de magn?sio que possui larga ?rea adsortiva e cargas eletrost?ticas positivas capazes de agir como um eficiente coagulante. Como fonte deste ?on, tem sido estudada a ?gua residu?ria das salinas, conhecida como ?gua-m?e (A-M), rica em diversos sais. Atualmente, ela ? lan?ada diretamente no mar, sem tratamento ou aproveitamento. Esta tese avaliou a capacidade de aplica??o desta ?gua residu?ria no tratamento de efluente de tinturaria contendo corante ?ndigo e pH alcalino. Os experimentos foram realizados em Testes de Jarro, simulando as etapas de coagula??o, flocula??o e decanta??o, variando o pH e a concentra??o do ?on magn?sio. Foram obtidas remo??es m?dias de 96%, 91% e 76% para turbidez, cor aparente e cor verdadeira, respectivamente, utilizando 200 mg/L Mg2+. A redu??o de custos com ?cido, quando se usou A-M em compara??o com o Al2(SO4)3, foi de 62%. Para a degrada??o da mat?ria org?nica remanescente no clarificado, em torno de 900 mg/L, foi aplicado o processo de oxida??o avan?ada: foto-Fenton. Os resultados preliminares apresentaram redu??es de 57% de carbono org?nico dissolvido (COD). De acordo com os resultados obtidos, a ?gua residu?ria das salinas pode ser aplicada, como coagulante, no tratamento f?sico-qu?mico do efluente de tinturaria de denim, sem ajustes pr?vios de pH, de forma eficiente e econ?mica
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Hasni, Abdellatif. "Etude des principales proprietes chimiques des solutions eau-chlorure de magnesium : application a la comprehension des phenomenes de corrosion sous contrainte de l'acier inoxydable austenitique 17-12-mo." Paris 6, 1988. http://www.theses.fr/1988PA066287.
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Etude du ph d'equilibre et du domaine d'acidite des solutions aqueuses de mgcl::(2) et de leur dependance vis-a-vis de la concentration et de la temperature des solutions. Analyse du comportement en corrosion sous tension de l'acier 17cr-12ni-2mo dans les solutions aqueuses de mgcl::(2) en fonction des differents parametres (concentration, temperature)
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Laboue, Blandine. "Preparation de cetones par acylation de composes organomanganeux : extension et amelioration de la methode." Paris 6, 1987. http://www.theses.fr/1987PA066464.
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Preparation des cetones acetyleniques fonctionnelles et de divers alcools tertiaires par acylation des composes organomagnesiens en presence de sels de manganese seuls ou associes a des sels de cuivre
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Chambreuil-Paret, Agnès. "Corrosion sous contrainte de mono et polycristaux d'aciers inoxydables austenitiques en milieu MgCl2 : analyse microfractographique et recherche d'améliorations du comportement." Grenoble INPG, 1997. http://www.theses.fr/1997INPG4205.
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Les aciers inoxydables austenitiques, ductiles a l'air, presentent en milieu chlorure a chaud une rupture macroscopiquement fragile, discontinue et composee de facettes cristallographiques. L'interpretation du caractere cristallographique de ces facies constitue une des cles de la comprehension des mecanismes d'endommagement en corrosion sous contrainte (csc). Aussi le premier objectif est d'etudier en details la microfractographie sur mono et polycristaux d'aciers de type 316l sollicites en milieu mgcl#2 a 117c a potentiel libre ( = 4. 10#-#7 s#-#1). Deux grands types de rupture sont observes : une rupture tres fragile qui souligne la possibilite de l'affaiblissement des liaisons interatomiques par le milieu corrosif et une rupture discontinue a l'echelle du micron sur les plans de glissement, representative de la fractographie observee sur polycristaux et qui est en bon accord avec le corrosion enhanced plasticity model. A partir des idees de ce modele, le deuxieme objectif de ce travail est la recherche d'une parade a la csc par le biais d'un preecrouissage avant csc. Deux types de preecrouissage sont testes. Le role negatif d'un preecrouissage en deformation monotone est reaffirme : les premieres fissures s'amorcent tres tot et la vitesse de propagation des fissures est augmentee. Ceci s'explique par le corrosion enhanced plasticity model, au travers de l'intensification des interactions corrosion-deformation locales. A l'inverse, un preecrouissage cyclique est particulierement benefique. Les premieres microfissures s'amorcent beaucoup plus tard et les niveaux de contrainte a rupture sont augmentes. Le retard de l'amorcage des premieres fissures s'explique par une structure de deformation de surface tres homogene qui s'oppose a une forte localisation de la dissolution anodique. Enfin la structure de dislocations creee en fatigue a saturation est une structure planaire de basse energie qui minimise les interactions corrosion-deformation a l'origine de la microfissuration.
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Edvardsson, Karin. "Evaluation of Dust Suppressants for Gravel Roads : Methods Development and Efficiency Studies." Doctoral thesis, KTH, Väg- och banteknik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-12359.
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Approximately 75 percent (300 000 km) of the total Swedish road network and 20 percent(20 000 km) of the national road network consists of gravel roads. One of the most significantproblems associated with gravel roads is traffic-generated dust emission, which contributes tothe deterioration of the road surface and acts as a major source of particulate matter releasedinto the atmosphere, thereby involving public economics, road safety, human health, andenvironmental quality. In order to bind the fine granular material, which is prone to rise into theair, dust suppressants are applied on roads on a yearly basis. Methods for evaluating the efficiency of dust suppressants will facilitate in the selection of themost appropriate product and its optimal application rate. For example, methods forsupervision of residual dust suppressant concentration are valuable tools for estimatinglongevity and optimal application rates, and, consequently, effectiveness of different products. Application of the proper dust suppressant to a gravel road ensures road safety and ridingcomfort as well as creating a cleaner and healthier environment for residents in buildingsadjacent to the road. It also reduces the need and cost for vehicle repair, road maintenanceactivities, and aggregate supplementation. Both field-based and laboratory research were performed to evaluate the efficiency of varioussuppressants and the influence such factors as product concentration, leaching, and fine materialcontent have on the efficiency of different products. Within the field-based research, a newlydeveloped mobile methodology was used to measure dust emission on numerous test sectionstreated with various dust suppressants. In general, all dust suppressants tested, except apolysaccharide (sugar) and products, which form a brittle surface crust, i.e. lignosulphonate andbitumen emulsion, showed acceptable dust reduction. Test sections treated with a magnesium- or calcium chloride solution were the most effectivelydust suppressed. The application of solutions instead of a solid salts achieves a more uniformproduct distribution and, therefore, probably a more efficient performance. By applying acalcium- or magnesium chloride solution instead of traditionally used solids, the cost for annualdust control, as well as the environmental impact from the release of these chemicals in theenvironment, can be reduced by 50 percent. A significant problem when using dust suppressants is their tendency to leach during rainfalldue to their soluble properties. Residual chloride could be detected in the gravel wearing courseover a longer period of time than lignosulphonate and, therefore, showed more effective longtermperformance. Optimal percentages of fine material for minimal lignosulphonate andchloride leaching were found to be 15 percent by weight and 10-16 percent by weight,respectively. Ions of calcium chloride seemed to initiate flocculation of clay particles, therebypreventing them from leaching. Still, the fine material in gravel wearing courses has to be replenished regularly as indicated by studies of the longevity of fine material. Loss up to80 percent was found after two years. Toxicity tests show that dust suppressant application for dust control purposes, at traditionallyused application rates, does not constitute a threat to sensitive aquatic life. Tests on subsoilwater samples indicated elevated chloride levels, which possibly could cause corrosion to pipes,but not high enough to flavour drinking water.QC20100616
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Yoon, Seok-Yeol. "A spectroelectrochemical study of aluminum and magnesium electrolysis in molten chlorides." Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/14796.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1987.MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE.
Bibliography: leaves 178-188.
by Seok-Yeol Yoon.
Ph.D.
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BEDET, THIERRY. "Traitement en premiere intention des crises de tachyarythmie par fibrillation auriculaire (tacfa) par le chlorure de magnesium (mgc12) : etude randomisee chez 52 patients." Besançon, 1992. http://www.theses.fr/1992BESA3023.
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Weatherholt, Riley Madison. "Road Salt Runoff into Freshwater Wetlands: Trends in SpecificConductance and Ion Concentration." Kent State University Honors College / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ksuhonors1557152479759316.
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VINCENT, JEAN-FRANCOIS. "Correction de l'alcalose metabolique de reventilation chez l'insuffisant respiratoire chronique par le chlorure de magnesium." Angers, 1992. http://www.theses.fr/1992ANGE1054.
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Palmer, Sara Jane. "Stability of hydrotalcites formed from Bayer refinery environmental control processes." Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/48672/1/Sara_Palmer_Thesis.pdf.
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Bauxite refinery residues (red mud) are derived from the Bayer process by the digestion of crushed bauxite in concentrated sodium hydroxide at elevated temperatures and pressures. This slurry residue, if untreated, is unsuitable for discharge directly into the environment and is usually stored in tailing dams. The liquid portion has the potential for discharge, but requires pre-treatment before this can occur. The seawater neutralisation treatment facilitates a significant reduction in pH and dissolved metal concentrations, through the precipitation of hydrotalcite-like compounds and some other Mg, Ca, and Al hydroxide and carbonate minerals. The hydrotalcite-like compounds, precipitated during seawater neutralisation, also remove a range of transition metals, oxy-anions and other anionic species through a combination of intercalation and adsorption reactions: smaller anions are intercalated into the hydrotalcite matrix, while larger molecules are adsorbed on the particle surfaces. A phenomenon known as ‘reversion’ can occur if the seawater neutralisation process is not properly controlled. Reversion causes an increase in the pH and dissolved impurity levels of the neutralised effluent, rendering it unsuitable for discharge. It is believed that slow dissolution of components of the red mud residue and compounds formed during the neutralisation process are responsible for reversion.
This investigation looked at characterising natural hydrotalcite (Mg6Al2(OH)16(CO3)∙4H2O) and ‘Bayer’ hydrotalcite (synthesised using the seawater neutralisation process) using a variety of techniques including X-ray diffraction, infrared and Raman spectroscopy, and thermogravimetric analysis. This investigation showed that Bayer hydrotalcite is comprised of a mixture of 3:1 and 4:1 hydrotalcite structures and exhibited similar chemical characteristic to the 4:1 synthetic hydrotalcite. Hydrotalcite formed from the seawater neutralisation of Bauxite refinery residues has been found not to cause reversion. Other components in red mud were investigated to determine the cause of reversion and this investigation found three components that contributed to reversion: 1) tricalcium aluminate, 2) hydrocalumite and 3) calcium hydroxide. Increasing the amount of magnesium in the neutralisation process has been found to be successful in reducing reversion.
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Bette, Sebastian [Verfasser], Wolfgang [Akademischer Betreuer] Voigt, Wolfgang [Gutachter] Voigt, and Robert E. [Gutachter] Dinnebier. "Über basische Chloride des Nickel(II) und Magnesiums : Strukturen, Phasenbildung und Löslichkeit / Sebastian Bette ; Gutachter: Wolfgang Voigt, Robert E. Dinnebier ; Betreuer: Wolfgang Voigt." Freiberg : Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2016. http://d-nb.info/1220912786/34.
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Benaboura, Ahmed. "Etude de la copolymerisation du styrene et de l'hexene-1 et du mode d'insertion du styrene en presence de catalyseurs de type "ziegler"." Paris 6, 1988. http://www.theses.fr/1988PA066059.
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Polymerisation du styrene et de l'hexene-1 en presence de catalyseurs a base de titane, sans organoaluminique, contenant ou non du chlorure d'aluminium et par du chlorure de magnesium. Influence d'addition de benzoate d'ethyle
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Neupane, Bhanu. "Excited state electronic structure, excitation energy transfer, and charge separation dynamics in various natural and artificial photosynthetic systems containing zinc and magnesium chlorins." Diss., Kansas State University, 2011. http://hdl.handle.net/2097/13105.
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Doctor of PhilosophyDepartment of Chemistry
Ryszard J. Jankowiak
This dissertation reports the low temperature frequency domain spectroscopic study of three different natural pigment protein complexes and one artificial antenna system. The main focus of this work is to better understand electronic structure, excitation energy transfer (EET), and electron transfer (ET) dynamics in these systems that could have impact on achieving higher efficiency in future artificial solar cells. In the first part of this dissertation, electronic structure and EET pathways in isolated intact CP43 prime protein complex, which is isolated from Cyanobacterium synechocystis PCC 6803 grown under iron stressed conditions, are investigated using low-temperature absorption, fluorescence, fluorescence excitation, and hole-burning (HB) spectroscopies. This work suggests that, in analogy to the CP43 complex of PSII core, CP43 prime possesses two quasi-degenerate low energy states, A prime and B prime. The various low-temperature optical spectra are fitted considering an uncorrelated EET model. This work suggests that for optimal energy transfer from CP43 prime to PSI, the A prime and B prime state chlorophylls belonging to each CP43 prime should face towards the PSI core. The second part of dissertation reports the photochemical HB study on novel Zinc bacterial reaction center (Zn-RC) from Rhodobacter sphaeroides and its β-mutant (Zn-β-RC). This study shows that ET in the two samples is similar; however, the quantum efficiency of charge separation in the mutant decreases by 60 %. This finding suggests that the coordination state of the HA site zinc bacteriochlorophyll does not tune the active branch ET. Simultaneous fits of various optical spectra using experimentally determined inhomogeneity provides more reliable electron phonon coupling parameters for the P870 state of both RC samples. In the last part of this dissertation, EET in a novel artificial antenna system (ethynyl linked chlorophyll trefoil, ChlT1) is investigated. EET time in ChlT1 is ~2 ps. ChlT1 in MTHF/ethanol glass forms four different types of aggregates, A1-A4. The EET time in A1 and A2 type aggregates slows down only by a factor of 5 and 7, respectively. This study suggests that ChlT1 and its aggregates can be used as efficient antenna systems in designing organic solar cells.
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Verrelli, D. I. "Drinking water treatment sludge production and dewaterabilityф." D. I. Verrelli, 2008. http://repository.unimelb.edu.au/10187/3521.
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The provision of clean drinking water typically involves treatment processes to remove contaminants. The conventional process involves coagulation with hydrolysing metal salts, typically of aluminium (‘alum’) or trivalent iron (‘ferric’). Along with the product water this also produces a waste by-product, or sludge. The fact of increasing sludge production — due to higher levels of treatment and greater volume of water supply — conflicts with modern demands for environmental best practice, leading to higher financial costs. A further issue is the significant quantity of water that is held up in the sludge, and wasted.One means of dealing with these problems is to dewater the sludge further. This reduces the volume of waste to be disposed of. The consistency is also improved (e.g. for the purpose of landfilling). And a significant amount of water can be recovered. The efficiency, and efficacy, of this process depends on the dewaterability of the sludge.In fact, good dewaterability is vital to the operation of conventional drinking water treatment plants (WTP’s). The usual process of separating the particulates, formed from a blend of contaminants and coagulated precipitate, relies on ‘clarification’ and ‘thickening’, which are essentially settling operations of solid–liquid separation.WTP operators — and researchers — do attempt to measure sludge dewaterability, but usually rely on empirical characterisation techniques that do not tell the full story and can even mislead. Understanding of the physical and chemical nature of the sludge is also surprisingly rudimentary, considering the long history of these processes.
The present work begins by reviewing the current state of knowledge on raw water and sludge composition, with special focus on solid aluminium and iron phases and on fractal aggregate structure. Next the theory of dewatering is examined, with the adopted phenomenological theory contrasted with empirical techniques and other theories.The foundation for subsequent analyses is laid by experimental work which establishes the solid phase density of WTP sludges. Additionally, alum sludges are found to contain pseudoböhmite, while 2-line ferrihydrite and goethite are identified in ferric sludges.
A key hypothesis is that dewaterability is partly determined by the treatment conditions. To investigate this, numerous WTP sludges were studied that had been generated under diverse conditions: some plant samples were obtained, and the remainder were generated in the laboratory (results were consistent). Dewaterability was characterised for each sludge in concentration ranges relevant to settling, centrifugation and filtration using models developed by LANDMAN and WHITE inter alia; it is expressed in terms of both equilibrium and kinetic parameters, py(φ) and R(φ) respectively.This work confirmed that dewaterability is significantly influenced by treatment conditions.The strongest correlations were observed when varying coagulation pH and coagulant dose. At high doses precipitated coagulant controls the sludge behaviour, and dewaterability is poor. Dewaterability deteriorates as pH is increased for high-dose alum sludges; other sludges are less sensitive to pH. These findings can be linked to the faster coagulation dynamics prevailing at high coagulant and alkali dose.Alum and ferric sludges in general had comparable dewaterabilities, and the characteristics of a magnesium sludge were similar too.Small effects on dewaterability were observed in response to variations in raw water organic content and shearing. Polymer flocculation and conditioning appeared mainly to affect dewaterability at low sludge concentrations. Ageing did not produce clear changes in dewaterability.Dense, compact particles are known to dewater better than ‘fluffy’ aggregates or flocs usually encountered in drinking water treatment. This explains the superior dewaterability of a sludge containing powdered activated carbon (PAC). Even greater improvements were observed following a cycle of sludge freezing and thawing for a wide range of WTP sludges.
Further aspects considered in the present work include deviations from simplifying assumptions that are usually made. Specifically: investigation of long-time dewatering behaviour, wall effects, non-isotropic stresses, and reversibility of dewatering (or ‘elasticity’).Several other results and conclusions, of both theoretical and experimental nature, are presented on topics of subsidiary or peripheral interest that are nonetheless important for establishing a reliable basis for research in this area.
This work has proposed links between industrial drinking water coagulation conditions, sludge dewaterability from settling to filtration, and the microstructure of the aggregates making up that sludge. This information can be used when considering the operation or design of a WTP in order to optimise sludge dewaterability, within the constraints of producing drinking water of acceptable quality.
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Hernandez, Laura. "Simulations numériques par méthode de Monte Carlo des transitions de phase dans les antiferromagnétiques anisotropes purs et dilués : FeCl2, FeBr2, FexMg1-xCl2." Toulouse, INSA, 1993. http://www.theses.fr/1993ISAT0006.
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L'interet de l'etude des systemes antiferromagnetiques tres anisotropes s'est sans cesse renouvele au cours des dernieres annees. Soumis a un champ magnetique, les systemes purs presentent un comportement tricritique et les systemes dilues sont une realisation physique du modele d'ising en champ aleatoire. Notre travail comporte deux parties. Dans la premiere, nous utilisons une simulation de monte carlo avec un modele qui prend en compte les caracteristiques essentielles de ces systemes. L'anisotropie, les interactions frustrees et en competition ont ete prises en compte pour chaque reseau. Pour fecl#2, un excellent accord quantitatif est trouve entre la valeur calculee du rapport de la temperature tricritique et de la temperature de neel et sa mesure experimentale. Pour febr#2, nos resultats montrent le caractere non ising de ce compose. Dans la seconde partie, nous appliquons notre modele au systeme dilue fe#xmg#1##xcl#2. Nous avons realise une etude systematique pour x=0. 9, 0. 8 et 0. 7. Des simulations de refroidissement (fc) et rechauffement (fh) sous champ et de montees et descentes de champ ont ete effectuees. Des irreversibilites dans les cycles fh-fc ont ete trouvees en accord avec l'experience. La forme des domaines magnetiques associes a ete etudiee. Nous montrons l'existence d'un point tricritique et son evolution avec la concentration. Enfin, nous avons analyse la possibilite de l'existence d'une phase verre de spin, a tres basse temperature et haut champ: nous montrons qu'aucune ligne critique n'existe pas dans cette region
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Bouchet, Alain. "Minéralogie et géochimie des roches altérées du chapeau de fer de Rouez (Sarthe)." Poitiers, 1987. http://www.theses.fr/1987POIT2303.
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L'oxydation de la pyrite provoque un lessivage de l'aluminium de plus en plus important vers la base de la zone oxydee. Le comportement du magnesium et de l'aluminium entraine la cristallisation de differents mineraux argileux interstratifies desordonnes dans les zones oxydees, intermediaires et cementees. Sous la zone cementee, les mineraux argileux des pelites sont remplaces par un assemblage interstratifie caracteristique de milieux acides. Dans la zone oxydee, les chlorites se transforment en interstratifie chlorite/saponite ferrifere. La composition de la saponite evolue vers celle de la stevensite ferrifere a la base de la zone oxydee. Dans la zone cementee, le fer est piege dans les sulfures. Les chlorites primaires sont totalement detruites par l'action des fluides acides
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Bensamka, Faouzi. "Etude par mesures de susceptibilite magnetique et par spectrometrie moessbauer du comportement verre de spin dans les composes isolants dilues fe : :(x)mg::(1-x)cl::(2)." Toulouse 3, 1986. http://www.theses.fr/1986TOU30028.
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Mise en evidence d'un comportement verre de spin aux basses temperatures et pour x
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Bendaoud, Rachid. "Propriétés magnétiques de particules finement divisées d'oxyde de fer Fe203 : étude de la dynamique du verre de SPIN FE:(0,3)MG::(0,7)CL::(2)." Toulouse, INSA, 1988. http://www.theses.fr/1988ISAT0001.
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Etude du comportement de deux systemes desordonnes composes l'un de fins cristallites de taille 100 a de fe::(2)o::(3) au comportement superparamagnetique; l'autre, d'un verre, de spin isolant. L' analyse experimentale a ete effectuee par susceptibilite statique, cycle d'hysteresis et susceptibilite dynamique. Mise en evidence de la taille des cristallites sur les proprietes magnetiques. Dans le cas du verre de spin, la variation thermique du temps de relaxation est bien decrite. Les resultats sont coherents avec une transition de phase a tc=0
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Oliveira, Roberta Camargos de. "Acúmulo de nutrientes, produtividade e qualidade de batata, cv. Asterix, sob fontes de fertilizantes potássicos." Universidade Federal de Uberlândia, 2013. https://repositorio.ufu.br/handle/123456789/12190.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThe high demand and response of potatoes to the addition of nutrients to the soil provides attention to relevant aspects related to fertility (application, quantity, sources). Adequate fertilization allows a balance between soil and plant nutrients, resulting in excellent returns for farmers and better quality produce for consumers. This study evaluated the development, productivity and quality of potato tubers, cultivar Asterix, after the application of two sources of potassium fertilizers and their combinations (KCl and K2SO4.2MgSO4), as well as nutrient absorption and nutritional diagnosis. The experiment was conducted in the county of Perdizes (MG). The experimental design was a randomized block with nine treatments and four replications as a split plot factorial. Plots were the treatments while subplots were plant sampling dates (biweekly). The amount of nutrients (N, P and K) used was based on physical and chemical analyses of soil and crop demand. Ninety quilograms of N, 180 kg of K2O and 750 kg of P2O5 were applied per hectare. Treatments consisted of application of the K2O dose in combinations of two sources of potassium fertilizer (KCl and K2SO4.2MgSO4). In general, the combination of sources of potassium fertilizers favors the accumulation of dry leaf, stem and tuber matter, with a quadratic response for leaves and stems and linear for tubers. Some proportions between the sources favored the accumulation of K in leaves and stems; however, these were not different from the application of each source alone. There was a gradual accumulation increase in the tubers during the crop cycle, with the greatest accumulations when the fertilizer proportions of the two sources of fertilizer were applied. The application of 100% of the fertilizer as KCl showed greater Cl accumulation in leaves, stems and tubers; however, not different from some combinations with K2SO4.2MgSO4. The order of deficiency obtained from the DRIS, in areas of high and low productivity were, respectively: Mn> Zn> P> Cu> K> Mg> Fe> B> N> S> Ca and Mg> Zn> K> Mn > Ca> P> B> S> Cu> N> Fe, whereas the order of excess were P> Fe> Mg> Zn> Mn> B> Ca> O> N> Cu> K and Cu> Zn> Fe> B> N> S> Mg> P> Mn> K> Ca. The nutritional unbalances obtained by IBN showed that soil nutrient levels should be monitored, looking for the improvement in nutrient dynamics along the successive crops. Productivity, percentage of soluble solids, total sugars, reducing sugars, starch, tuber dry matter, moisture and ash contents did not differ between sources of potassium fertilizers: KCl and K2SO4.2MgSO4 and their combinations, for cv. Asterix at the dose of 180 kg K2O ha-1, possibly because the amount applied was not sufficient to reflect the potential deleterious effects of chlorine.
A alta exigência e a resposta da cultura de batata à adição dos nutrientes ao solo proporcionam relevante atenção aos aspectos relacionados à fertilidade (aplicação, quantidade, fontes). A adubação adequada permite um balanço entre os nutrientes no solo e na planta, o que culmina em excelentes rendimentos aos produtores e produtos de melhor qualidade aos consumidores. Assim, objetivou-se avaliar o desenvolvimento, a produtividade e a qualidade de tubérculos de batata, cultivar Asterix, frente à aplicação de duas fontes de fertilizantes potássicos e as combinações destas (KCl e K2SO4.2MgSO4), bem como a absorção de nutrientes e a diagnose nutricional. O experimento foi conduzido no município de Perdizes-MG, de maio a outubro de 2011. O delineamento experimental utilizado foi o de blocos ao acaso, com nove tratamentos e quatro repetições, em esquema fatorial com parcela subdividida. As parcelas referiram-se aos tratamentos, e as subparcelas às épocas de coletas de plantas (quinzenais). A quantidade de nutrientes (N, P e K) utilizada foi baseada na análise física e química do solo e na necessidade da cultura. Foram aplicados 90 kg ha-1 de N, 180 kg ha-1 de K2O e 750 kg ha-1 de P2O5. Os tratamentos consistiram na aplicação da dose de K2O sob a combinação de duas fontes de fertilizantes potássicos (KCl e K2SO4.2MgSO4). Em geral, a combinação entre as fontes de fertilizantes potássicos favorece o acúmulo de massa seca de folhas, hastes e tubérculos, com resposta quadrática para folhas e hastes e linear para tubérculos. Algumas proporções entre as fontes favorece o acúmulo de K em folhas e hastes, porém não difere da aplicação de forma isolada. Nos tubérculos há aumento gradativo com o decorrer do ciclo, sendo os maiores acúmulos onde as proporções entre as duas fontes do fertilizante é aplicado. A aplicação de 100% do fertilizante via KCl apresentou maiores acúmulos de Cl em folhas, hastes e tubérculos, porém não se diferiu de algumas combinações com K2SO4.2MgSO4. As ordens de deficiência, obtidas a partir do DRIS, nas áreas de alta e baixa produtividade foram respectivamente: Mn>Zn>P>Cu>K>Mg>Fe>B>N>S>Ca e Mg>Zn>K>Mn>Ca>P>B> S>Cu>N>Fe, ao passo que a ordem de excesso observada foram P>Fe>Mg>Zn>Mn>B>Ca>S>N>Cu>K e Cu>Zn>Fe>B>N>S>Mg>P>Mn>K>Ca. Os desbalanços nutricionais obtidos pelo IBN evidenciam que os níveis de nutrientes no solo devem ser acompanhados, buscando melhoria na dinâmica dos nutrientes ao longo dos cultivos sucessivos. A produtividade, a porcentagem de sólidos solúveis, os açúcares totais, os açúcares redutores, o amido, a massa seca de tubérculos, a umidade e as cinzas não diferem entre as fontes de fertilizantes potássicos: KCl e K2SO4.2MgSO4 e combinações entre elas, na cv. Asterix, na dose de 180 kg ha-1 de K2O, possivelmente a quantidade aplicada não foi suficiente para refletir o potencial efeito deletério do cloro.
Mestre em Agronomia
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Allan, Shawn Michael. "Reactive replacement and addition of cations in bioclastic silica and calcite." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/19239.
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Thesis (M. S.)--Materials Science and Engineering, Georgia Institute of Technology, 2005.Committee Chair: Kenneth Sandhage; Committee Members: Joe Cochran, Robert Snyder and Tom Sanders. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Alvarez, Gonzalez Eleuterio. "Substitution d'ethers et d'alcools allyliques par differents nucleophiles en presence de complexes de nickel(0) : synthese stereoselective des dienes-1,4 a partir des sulfones dieniques avec le chlorure d'isopropylmagnesium en presence de sels de." Paris 6, 1987. http://www.theses.fr/1987PA066064.
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Brunner, David R. "The Composition and Distribution of Coal-Ash Deposits Under Reducing and Oxidizing Conditions From a Suite of Eight Coals." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2642.
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Eighteen elements, including: carbon, oxygen, sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, potassium, calcium, titanium, chromium, manganese, iron, nickel, strontium, and barium were measured using a scanning electron microscope with energy dispersive spectroscopy from deposits. The deposits were collected by burning eight different coals in a 160 kWth, staged, down-fired, swirl-stabilized combustor. Both up-stream and down-stream deposits from an oxidizing region (equivalence ratio 0.86) and reducing region (equivalence ratio 1.15) were collected. Within the deposits, the particle size and morphology were studied. The average particle cross-sectional area from the up-stream deposits ranged from 10 - 75 µm2 and had a standard deviation of 36 - 340 µm2. These up-stream particles were of various shapes: spherical, previously molten particles; irregular particle that had not melted, hollowed spherical shells; and layered or strands of particles. These particles were a mixture of burned and unburned coal being deposited at various stages of burnout and having completed some burnout after deposition. The average particle cross-sectional area from the down-stream deposits ranged 0.9 - 7 µm2 and the standard deviation range of 2.6 - 30 µm2. The shape of the particles on the bottom sleeves are typically spherical indicating melting prior to deposition. Particles contained a distribution of elemental compositions that were not tightly grouped on ternary phase diagrams. This indicated that particles were not single compounds or phases but each particle contained a mixture of multiple compounds. Coals' deposit sulfur was strongly correlated with the calcium and iron content of the ASTM ash analysis. The low rank sub-bituminous and lignite coals that had high calcium content produced high sulfur deposits, particularly in the oxidizing region, down-stream deposits. The high iron bituminous coals, also produced high sulfur deposits, but more so in the reducing region, up-stream deposits. The low calcium and low iron coals produced low sulfur deposits. Mahoning was an exception being high in iron content but remaining low in sulfur content in the deposit. Gatling coal showed numerous deposit particles that contained only iron and sulfur consistent with the high pyrite content of Gatling coal. The average concentration of chlorine was insignificant in all of the deposits with the concentration being less than 100 ppm. Individual particles containing chlorine were found and were associated with potassium, sodium, and iron.
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de, Bakker Jan. "The recovery of magnesium oxide and hydrogen chloride from magnesium chloride brines and molten salt hydrates." Thesis, 2011. http://hdl.handle.net/1974/6337.
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Hydrochloric acid leaching of saprolite nickel ores has been proposed as an effective means of recovering nickel and cobalt. However, the leach produces a concentrated brine of magnesium chloride which must be hydrolyzed to recover the HCl lixiviant. The processing of carnallite similarly produces a concentrated MgCl2 brine; converting this brine into HCl and MgO provides an attractive way of adding value while effectively disposing of this waste product.
Direct pyrohydrolysis of magnesium chloride brines by the reaction,
MgCl2,a + H2Oa MgOs + 2HClg
is energy-intensive as large volumes of water must be evaporated. The energy cost is high, and the HCl stream produced is limited to approximately 20 wt% HCl. This thesis explores alternative methods of obtaining HCl from aqueous magnesium chloride solutions. Two methods are considered: the hydrolysis, under autogenous pressure, of concentrated MgCl2 molten salt hydrates; and the precipitation of magnesium hydroxychloride compounds such as 2MgO·MgCl2·6H2O and 3MgO·MgCl2·11H2O, which are subsequently decomposed at high temperature.
Considerable experimental difficulties were encountered in studying pressure hydrolysis of molten salt hydrates, despite extensive equipment modifications. Ultimately, the work moved on to precipitation and decomposition of hydroxychlorides. This was found to bear promise, and conceptual flowsheets based on these reactions are presented. A phase stability diagram giving the areas of predominance of the different hydroxychloride phases is presented, and fundamental thermochemical data are derived. The results of a kinetic study on magnesium hydroxychloride thermal decomposition are also presented.Thesis (Ph.D, Mining Engineering) -- Queen's University, 2011-03-11 10:14:53.455
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KUO, CHI-I. "MAGNESIUM-CHLORIDE SUPPORTED HIGH-ACTIVITY CATALYST FOR OLEFIN POLYMERIZATION." 1985. https://scholarworks.umass.edu/dissertations/AAI8517122.
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Magnesium Chloride supported catalyst with proper external Lewis-base has high activity and high stereospecificity for olefin polymerization. The supported CW-catalyst MgCl(,2)/Ethylbenzoate/p-cresol/AlEt(,3)/TiCl(,4) with cocatalyst AlEt(,3)(.)Methyl-p-toluate has been thoroughly characterized. Chemical composition of supports and catalyst have been determined by elemental analysis and gas chromatography. Double redox titrations showed the distribution of Ti oxidation states in catalyst were 50% of Ti('+4), 40% of Ti('+3) and 10% of Ti('+2). Only one fifth of the Ti('+3) was observable by EPR. The addition of coactivators reduced Ti to lower oxidation states: 10% of Ti('+4), 70% of Ti('+3) and 20% of Ti('+2). The physical states of the materials obtained during each stages of catalyst preparation were studied by BET, porosimetry and x-ray diffraction techniques. Final catalyst has surface area ca. 110 - 150 m('2) g('-1). The ultimate crystallite size 20 A - 30 A of MgCl(,2) was obtained by ball-milling with ethyl benzoate for 60 h. By comparing the profiles of polymerization of propylene to insoluble PP and of decene-1 to soluble PD with the same catalyst. We concluded that the polymerization rate decay is not caused by monomer diffusion limitations. The kinetic of propylene polymerization was studied using same catalyst. The active sites concentration were determined by radio-tagging with tritiated methanol and ('14)CO. The results are in agreement with those obtained by kinetic methods. There are at least four different kinds of active center exist in catalyst. By varying polymerization conditions such as Cat , C(,3)H(,6) , temperature and Al to Ti ratio, the propagation rate constant K(,p), activating energy of propagation, (DELTA)E(,p), the termination constant, K(,t), were determined. The average molecular weight and molecular weight distribution have been examined by GPC, viscometry, and end group analysis. The rate constant of chain transfer with monomer, K(,tr,M), and rate constant of (beta)-hydride transfer, K(beta), were calculated. The effect of hydrogen on propylene polymerization has been studied. The rate of polymerization was increased with H(,2) that is caused by the increasing of active centers.
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Duffy, Douglass. "Saprolite Leaching and Iron Control in Concentrated Magnesium Chloride Brines." Thesis, 2013. http://hdl.handle.net/1807/35600.
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MgCl2 brines present a number of potential advantages for the processing of saprolite ores for nickel production. Concentrated MgCl2 solutions enhance the activity of acid used, allow atmospheric leaching at elevated temperature and inhibit magnesium dissolution, which reduces acid consumption and increases metal selectivity. However, with a chloride system it is economically requisite to recover hydrochloric acid, conventionally accomplished by pyrohydrolysis. This work was performed in conjunction with a novel flowsheet for the processing on saprolite ores, which recovers HCl by the precipitation and subsequent decomposition of magnesium hydroxychlorides, alleviating some of the issues with pyrohydrolysis. Leaching and iron control experiments have been conducted in concentrated MgCl2 brines, up to 4.5 m, to determine the most amenable process conditions. It was determined that > 95% extraction of metals was possible using both aqueous and gaseous HCl. In addition, the feasibility of iron control by precipitation with MgO addition was proven.
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Chen, Wei-tong, and 陳威統. "Electrowinning of magnesium metal from high temperature molten chloride electrolytes." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/49859125446875922793.
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碩士國立雲林科技大學
化學工程與材料工程系碩士班
100
In this study, the reaction at the electrode surface was studied by cyclic voltammetry method in the ternary molten electrolytes. In addition, various electrowinning processes of magnesium metal from ternary molten electrolytes system have been studied. The reduction peak area was increase with increased molar composition of MgCl2 by cyclic voltammetry measurement, in which the molar composition increased from 30:70 mol%, 40:60 mol%, 50:50 mol%, to 60:40 mol %. Results indicated that the reduction peak area of cyclic voltammetry increased with increasing MgCl2 content from 30 mol% to 40 mol%. Whereas excessive amount of the MgCl2 increased the viscosity of electrolytes, which lead to decreased in diffusion coefficient of Mg2+ from 1.88X10-10 to 8.84X10-14. The composition of 40:60 mol% MgCl2 - (NaCl-KCl) molten salts was selected as electrolyte, carbon rod as anode, and stainless steel as cathode. The experimental results revealed that lager magnesium particles can be obtained in the range of 3.5 V to 4.5 V constant potential. The purity of magnesium obtained by electrowinning constant potential method, and pulse potential method was 93% and 98%, respectively.
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HUANG, BIN-JIE, and 黃彬杰. "Electrolytic refining of magnesium and lithium metals with molten salt chloride electrolyte." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/4r4e3n.
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碩士國立雲林科技大學
化學工程與材料工程系
103
This study investigated the preparations of lithium and magnesium metal with molten chloride electrolytes. The preparation of lithium was carried out by a direct current (DC) electrolysis with binary 60:40 (mol%) LiCl-KCl molten salt bath,and moreover, the best conductivity and diffusion rate were obtained under this concentration. The electrolysis experiment of binary 60:40 (mol%) LiCl-KCl molten salt bath was proceeded under the DC potential 5-10V. However, at DC constant pontential, 89.70% current efficiency and 98.44% purity of lithium were obtained and discussed.Also, a 9V pulsed electrolysis under different duty cycles (0.3, 0.4, 0.5, 0.6, 0.7 and 0.8) were carried out and the results were discussed. The preparation of magnesium metal was carried out by a DC and pulsed current electrolysis with ternary NaCl-CaCl2-MgCl2 molten salt electrolyte. The result shows that the (70mole%NaCl-30mole%CaCl2)-MgCl2 = 80: 20 (mol%) molten salt has the best diffusion rate from the cyclic voltammetry method. In addition, the average particle size and current efficiency of magnesium metal, obtained by the constant pontential electrolytic preparation, were optimal at 4-5V potential. The pulsed potential electrolysis was also carried out under 4-5V and various duty cycles, the results exhibit that the pulsed current efficiency is 68.96% and magnesium metal purity is above 2N. Keywords: pulsed current electrolysis, magnesium, lithium, molten salt, cyclic voltammetry.
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Naicker, Omasha. "Gas-phase ethylene polymerization studies using a magnesium chloride-supported Ziegler-Natta catalyst." Thesis, 2006. http://hdl.handle.net/10413/1436.
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Kuo, Lu-Hsia, and 郭魯俠. "Lyocell Fabric with NaOH Soda Process and Magnesium Chloride Finishing for Fibrillation Researc." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/sktr6s.
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碩士國立臺北科技大學
有機高分子研究所
96
In the textile industry, man made fiber, Lyocell is one on the top of the list. It has unique bouncy, cool & drape hand touch like no other material could be. Especially the peach skin effect that form by dyeing and mechanical washing, so called fibrillation process. The tradition method of fibrillation is done by mechanical washing, fabric in rope form of shapes rotate consistently in dyeing lot. With certain amount of soda, degrees of temperature, friction level and timing conditions to control the production. Final step is enzyme washing which elevated the extra / left over fibers the caused while fibrillation. However, the tradition method has been difficult to control the quality, has limited production capacity and higher cost wise. This research is base on open width production by using NaOH & MgCl2•6H2O to dissolve fibers. The advantage is to stabilize the quality consistently, lower the loss & cost, increase the production capacity and develop finishing for garment washing. The purpose of this research is focusing on dyeing industry, using different level of alkalinity of NaOH dissolving liquid under mercerizing finishing process with tension. Then apply with MgCl2•6H2O hemolysic HC1 method under high temperature which will cause fiber break down. Then apply with different examination and testing, and came up with result of when Tencel® experience NaOH finishing, amorphous region will be damaged and the changes of increasing of orientation but decreasing of fabric strength & moisture rate. Observation of Tencel® under desizing, setting & NaOH finishing, the a Peak will be increased from 356℃ to range of 361℃ & 368℃, it appears that when orientation increased, the fabric strength will be decreased. And the higher the concentration the stiffer hand it will gets. The mercerize process could not be same as cotton fabric with 22B’e~24B’e, suggested alkalinity as 13B’e~15B’e. And with MgCl2•6H2O finishing, the fibrillation could be achieve, but has to coordinate with mercerize & washing afterwards as a combination. The elevation of dissolved Cellulose is done by light scrub or abrasion & friction under washing. At the same time, extremely fine & short fiber will be produced. And now the fabric has snow white & peach skin effect just the same as the fibrillation done by mechanical washing. (Tradition way of fibrillation) The fibrillation requirement & conditions of MgCl2•6H2O had to depends on the concentration , temperature & timing. It will had different results of level of peach skin & strength. So the key point is to consider the balancing between peach skin & fabric strength as basis. The conclusion for this research is that the most ideal combination as followed, when the mercerizing is at 13B’e, concentration of MgCl2•6H2O at 20Gram/Liter & temperature at 180℃ with 120 seconds.
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Бутковський, Артур Станіславович. "Аналіз технології електролітичного виробництва магнію." Магістерська робота, 2020. https://dspace.znu.edu.ua/jspui/handle/12345/4838.
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Бутковський А. С. Аналіз технології електролітичного виробництва магнію : кваліфікаційна робота магістра спеціальності 136 "Металургія" / наук. керівник Р. М. Воляр. Запоріжжя : ЗНУ, 2020. 78 с.UA : Проведено аналіз різних технологічних і конструктивних заходів, спрямованих на інтенсифікацію процесу електролітичного виробництва магнію. Визначено межі теплового регулювання роботи електролізерів за допомогою зміни режиму водяного охолодження і визначена динаміка зміни температури електроліту в залежності від зміни параметрів відводу тепла теплоносієм.
EN : The analysis of various technological and constructive measures aimed at intensifying the process of electrolytic production of magnesium is carried out. The boundaries of thermal regulation of the operation of electrolyzers by changing the water cooling mode are determined and the dynamics of the change in the temperature of the electrolyte, depending on the change in the parameters of heat removal by the coolant, is determined.
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Julio, Betancourt Gustavo Adolfo. "Effect of De-icer and Anti-icer Chemicals on the Durability, Microstructure, and Properties of Cement-based Materials." Thesis, 2009. http://hdl.handle.net/1807/17778.
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A comprehensive study was conducted on the effects of de-icer and anti-icer chemicals on cement-based materials. Portland cement mortars and concretes were exposed to over 16 chloride-based and non-chloride-based generic and commercial products and changes in cement-based material properties were measured. Deleterious chemical actions of several types of these products on cement-based materials were observed, departing from the well-known position that attributes the concrete damage from such salts mainly to physical actions under freezing and thawing exposure.
Independent of freezing and thawing exposure, mortars and concretes exposed to concentrated calcium chloride and magnesium chloride solutions were found to undergo severe deterioration whereas those exposed to sodium chloride did not. The mechanisms of deterioration are complex with factors such as concentration, temperature, and availability of calcium hydroxide playing important roles. It was found that the formation of calcium oxychloride of the form 3Ca(OH)2.CaCl2.12H2O, and the 3- and 5-form magnesium oxychloride, 3Mg(OH)2.MgCl2.8H2O and 5Mg(OH)2.MgCl2.8H2O, were the main causes for the severe deterioration, and to a lesser extent brucite, gypsum, and magnesium silicate hydrate (M-S-H). The instability of these oxychloride compounds when subjected to conditions normally encountered in sample preparation is suggested as the reason why field investigations have failed to relate distressed concrete to chemical attack by such de-icer and anti-icer chemicals.
Concentrated solutions of calcium magnesium acetate were also found to be harmful to cement-based materials by dissolution of calcium hydroxide and formation of calcium acetate hydrate, whereas low concentrated solutions tended to cause slow deterioration by magnesium attack forming brucite, gypsum, and M-S-H. Potassium acetate chemicals did not cause significant deterioration in mortars when these products were diluted (25% by mass), but undiluted products (50% by mass) caused considerable distress in concrete specimens.
The combined effect of chemical attack impairing concrete mechanical properties and subsequent salt scaling damage was proposed as the most likely mechanisms of field deterioration.
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LIN, SU-GING, and 林素卿. "Synthesis on Al, Mg binuclear and polynuclear bridged complexes:reactions of aluminum chloride with bis (dialkyl amino) magnesium." Thesis, 1989. http://ndltd.ncl.edu.tw/handle/52731584417204305297.
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Johnson, Janice M. "The effects of sodium, calcium and magnesium chloride salts on the chymosin-induced coagulation of skim milk." 1991. http://catalog.hathitrust.org/api/volumes/oclc/23986008.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 1991.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 164-183).
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Pugliese, Chiara, Marcello Canonaco, Alfonsina Gattuso, and Rosa Mazza. "Effect of different formulations of magnesium chloride, used as anaesthetic agents, on the performance of the isolated heart of Octopus vulgaris." Thesis, 2017. http://hdl.handle.net/10955/1300.
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Scuola di Dottorato Life Sciences, Ciclo XVIII, a.a. 2015-2016Il cloruro di magnesio (MgCl2) rappresenta l'anestetico più comunemente utilizzato per i cefalopodi; tuttavia, i suoi effetti fisiologici compresi quelli a livello cardiaco non sono ben caratterizzati. Nel presente studio, utilizzando come modello sperimentale il polpo comune Octopus vulgaris, è stato valutato mediante la tecnica del cuore isolato e perfuso: a) se l'esposizione dell’animale in vivo (immersione) a diverse formulazioni di MgCl2 induce effetti sulla funzione cardiaca in vitro che potrebbero danneggiare il recupero dall'anestesia; b) l’effetto diretto della perfusione con diverse formulazioni di MgCl2 sulla funzione cardiaca. Per gli esperimenti in vivo, sono state utilizzate le seguenti formulazioni con relativi tempi di esposizione: i) MgCl2 3,5% in acqua di mare (MgCl2 sw, 20min); ii) MgCl2 3,5% (1:1, acqua di mare:acqua distillata, 20min); miscela di MgCl2 (1,12%) + etanolo (1%) (Mix, 20min e 45min); ipotermia (4°C, 5-10min). Alle condizioni basali, i cuori prelevati dopo esposizione ai vari trattamenti anestetici, inclusa l’ipotermia, sono stati in grado di lavorare con carichi emodinamici simili a quelli in vivo e di produrre valori fisiologici di gittata sistolica. In condizioni di carico emodinamico (incrementi di precarico), i cuori rimossi da animali esposti in vivo ad MgCl2 sw (20min) o al Mix (20min) hanno mostrato una performance cardiaca (in termini di risposta di Frank-Starling) comparabile a quella di animali anestetizzati mediante ipotermia. Al contrario, sia l'esposizione a MgCl2 (1:1, 20min), che al Mix (45min) ha mostrato un significativo deterioramento della risposta di Frank-Starling in termini di ridotta capacità di rispondere agli incrementi di precarico. Dopo esposizione ad ipotermia, la perfusione dei cuori isolati con concentrazioni crescenti delle diverse formulazioni di MgCl2, ha prodotto un effetto bradicardico dose-dipendente (e in alcuni casi arresto cardiaco) ed una riduzione della gittata cardiaca e del volume sistolico, indicativi di un effetto diretto dei trattamenti anestetici sul cuore. Al contrario, la perfusione con dosi crescenti di solo etanolo non ha causato alcuna variazione della frequenza cardiaca, indicando che l’effetto bradicardico evidenziato con la soluzione Mix è attribuibile al cloruro di magnesio. L'espressione di HSP70 e caspasi-3, e la fosforilazione di JNK e p38MAPK sono stati determinati in omogenati cardiaci, ottenuti da esemplari di O. vulgaris esposti alle diverse formulazioni di cloruro di magnesio o ad ipotermia (4°C). I risultati hanno evidenziato un incremento dell’espressione di HSP70 (ma non della caspasi-3); in particolare, l’espressione di HSP70 è risultata essere inferiore nei cuori prelevati da animali esposti ad ipotermia, rispetto a quelli esposti alle diverse formulazioni di MgCl2. Tra questi ultimi, nessuna differenza quantitativa è stata evidenziata tra le diverse formulazioni, ad eccezione del Mix 45min, effetto dovuto probabilmente al maggior tempo di esposizione. L'aumento della fosforilazione di JNK e p38MAPK, parallelo all'aumentata espressione di HSP70, lascia supporre il coinvolgimento di queste MAPKs nell'espressione di HSP70. Nell'insieme i dati dimostrano che, a condizione che l'esposizione in vivo al 3,5% di MgCl2 in acqua di mare o ad una miscela di MgCl2+etanolo sia limitato a ~ 20min, gli effetti residui sulla funzione cardiaca non influenzano il recupero post-anestesia. Inoltre, l’espressione di HSP70 che può giocare un ruolo citoprotettivo nella risposta allo stress durante l'anestesia, parallela alla mancata espressione della caspasi-3 in tutti i tessuti analizzati, permette di escludere eventi pro-apoptotici da parte di tutti i trattamenti anestetici. Nell’insieme questi risultati possono contribuire alla discussione circa le pratiche anestesiologiche da utilizzare anche in relazione all'applicazione della nuova Direttiva 2010/63 / UE per i cefalopodi.
Università della Calabria