Etude expérimentale et modélisation, en fonction du pH et de la concentration en NaCl, du système ternaire U(VI)-NaCl-H2O à T = 155°C et pression de vapeur saturante. Une étude expérimentale sur la solubilité de l'U(VI) dans des saumures de NaCl (0.5 – 6 M) en fonction du pH (3-13) a été réalisée à T = 155°C et pression de vapeur saturante. Les résultats obtenus ont montré que la phase solide initiale UO3 se transforme en de multiples phases solides d'uranates de sodium de formule générale Na2xUyO(x+3y) hydratés dont le rapport molaire Na/U croit avec l'accroissement du pH et de la concentration de NaCl. La solubilité de l'U(VI) est directement gouvernée par trois paramètres physico-chimiques : le pH, le ligand Cl- et le cation Na+. Les deux premiers favorisent fortement la solubilité de l'U(VI) sous forme de complexes d'U(VI) avec les ligands OH- et Cl- à pH = 4. A la différence des deux premiers paramètres, le cation Na+ inhibe la solubilité de l'uranium (VI) en le précipitant sous forme de multiples composés d'uranates de sodium très peu solubles. Les résultats de mesures de solubilité de l'U(VI) obtenues servent de base de données de référence pour calculer les variations de la concentration de chaque complexe soluble d'U(VI) en fonction de deux paramètres, pH et [Na], à l'aide d'une équation de type exponentielle d’un paraboloïde elliptique négatif. Un modèle empirique a également été mis au point, à partir des équations de Pitzer, afin de déterminer, de manière continue, les variations des divers paramètres physico-chimiques des ions solubles présents dans une saumure de NaCl en fonction de quatre paramètres : pH, [Na], T et P du milieu réactionnel. Ce modèle est valable jusqu’à [NaCl] = 6M, T = 300°C et P = 100 MPa. / An experimental study on the solubility of U(VI) in concentrated (0.5-6.0 M) NaCl solutions as a function of pH (3-13) has been realized at 155°C and saturation vapor pressure. The obtained results indicate that the initial solid phase UO3 initial solid phase is transformed into multiple solid phases of hydrated sodium uranates with general formula Na2xUyO(x+3y), the Na/U molar ratio of which increases with increasing pH and NaCl concentration. The solubility of U(VI) is directly dependant of three physico-chemical parameters : the pH, the Cl- ligand, and the Na+ cation. The first two parameters strongly favour the U(VI) solubility in the form of aqueous U(VI) complexes with the OH-and Cl- ligands at a pH = 4, while the Na+ cation inhibits the solubility of U(VI) as it precipitates into various low solubility sodium uranates. The results of solubility measurements obtained for U(VI) serve as a reference data base for the calculation of concentration variations of each soluble U(VI) complex as a function of two parameters, pH and [Na], with the use of a negative elliptic paraboloïd exponential. An empirical model has also been developed from the Pitzer equations in order to determine, in a continuous way, the variations of various physico-chemical parameters of the soluble ions present in the concentrated NaCl solutions as a function of four parameters: pH, [Na], T and P of the reaction medium. This model is valid up to [NaCl] = 6M, T = 300°C and P = 100 MPa.

A nanofilm rotation method is developed to study the rotation of nanograins and the formation of various low energy interfaces. Epitaxial (100), (110), (111) and (112) NiO nanofilms are prepared by ion beam sputtering onto the (100), (110), (111) and (112) surfaces of NaCl single crystal. By overlapping of the above films with an angle difference, and annealing at relatively low temperatures 100 ¢Jthe nanograins are induced to rotate till a metastable interface is reached. The rotation process and the metastable interfaces are determined by transmission electron microscopy. Many new interfaces between mixed planes are found, and their orientation relationships and structures are analyzed. The study discovered eight groups of metastable orientation relations, respectively, which have not been reported in literatures. 2¡¦ orientation relationship is [11 ]( 10)//[01 ]( 11) 2¡¦¡¦ orientation relationship is [00 ]( 10)//[ 0 ]( 11) 4e1 orientation relationship is [13 ]( 12)//[110](00 1) 4¡¦ orientation relationship is [1 1]( 12)//[0 0](00 1) 4e2 orientation relationship is [13 ]( 12)//[100](00 1) 5¡¦ orientation relationship is [ 1 ]( 12)// [01 ] ( 11) 6¡¨ orientation relationship is [110]( 12)// [001] ( 10) 6¡¦¡¦¡¦ orientation relationship is [110]( 12)// [ 1] ( 10)

The stable interfaces between NiO and ZrO2 reached by nanofilms interface rotation method are reported in this study. Epitaxial nanofilms of NiO and ZrO2 were synthesized on single crystal NaCl (001), (011), (111) surfaces. All nanofilms are investigated by transmission electron microscopy and selected-area diffraction (SAD) patterns. Composite nanofilms were formed by overlapping nanofilms of NiO and ZrO2 at difference angles and thermally treated. The rotation process and final stable interfaces in the overlapped nanofilms are analyzed by SAD patterns. Orientation relationships and interface rotation are analyzed. This study found five new interfaces. (1) (001)N/ Z¡A[110]N//[110]Z (2) (001)N/ Z¡A[100]N//[110]Z (3) N/ Z¡A[110]N//[110]Z (4) N/ Z¡A[111]N//[110]Z (5) N/ Z¡A[001]N//[110]Z

Ti thin films were deposited by a radio frequency ion-beam sputtering system. Deposition resulted from sputtering a Ti target (99.995%) with an Ar ion beam. Epitaxial TiO thin films with different orientations, which came from oxidizing Ti thin films, were prepared on single-crystal NaCl substrate. The formation of epitaxial TiO2 thin films (anatase or rutile phase) by oxidation of epitaxial TiO thin films was investigated. The composition, microstructure, and orientation relationships between interfaces were analyzed by TEM and Fourier transformation in the present report. Epitaxial TiO thin films with different orientations were prepared on single-crystal NaCl substrate in the present study. The formation of epitaxial TiO2 thin films (anatase or rutile) by oxidation of epitaxial TiO thin films, which were first grown on different NaCl surfaces, was investigated. The composition, microstructure, and orientation relationships between interfaces were analyzed by TEM and Fourier transformation in this report. The TiO to anatase phase transformation has been studied by transmission electron microscopy in this Article. It is shown that prior formation of TiO from Ti film can induce the formation of anatase by thermal oxidation in air, otherwise only rutile is formed. Ti film deposited on the NaCl (001) surface is induced to form epitaxial TiO film by thermal oxidation in air. Further thermal oxidation in air partially transformed TiO into anatase (A) with a parallel orientation relationship of {200}A // {200}TiO. Detailed analysis of the lattice fringes image of the specimen reveals the presence of very high density of misfit dislocations. The TiO to anatase transformation is reversible as further annealing in a vacuum can turn the anatase back into TiO and eliminates the misfit dislocations. The transformation is analyzed in terms of the crystal structure, orientation relationship, and the dislocation distribution, which show that the TiO to anatase transformation is due to the close similarity between their structures. (Chapter 1) The anatase TiO2 (001) surface was shown to have superior photoreactivity. Epitaxial anatase (001) films used to be grown on single-crystal SrTiO3 and LaAlO3 substrates. It is shown in this report that these films can be grown also on the NaCl substrate, which is much cheaper and easily prepared. Epitaxial TiO (001) films were first grown on the NaCl (001) substrate. By testing the TiO-to-anatase transformation over temperature and time ranges, an epitaxial anatase (001) film was prepared by simple thermal oxidation in air. The formation of a single-variant anatase (001) film instead of a multiple-variant film is discussed in this report. (Chapter 2) An epitaxial rutile (100) thin film has been grown on NaCl substrate instead of other more expensive substrates. An epitaxial TiO (111) thin film with minor Ti phase was first deposited on the NaCl (111) surface by thermal evaporation. It was then transformed into the epitaxial rutile (100) thin film by subsequent thermal oxidation in air. TEM was used to analyze the phases and the orientation relationship. Our previous result showed that an epitaxial anatase (001) film was formed on the NaCl (001) surface in a similar process. The substrate-dependent formation of different TiO2 phase is also discussed in terms of the mismatch of the interfaces. (Chapter 3)

This experiment use NaCl (001) single crystal as substrate, and the target is zinc oxide, to generate a-plane (112 ¡Â0) zinc oxide nanothim. The nanofilm is used as a buffer layer generating by Ion Beam Sputtering, and then increasing the thickness by Plasma sputtering. Part of specimens to proceed atmospheric heat treatment with different temperature and time, and part of specimens to change the ratio of the gas when the thin film is growth, then use of Transmission electron microscopy (TEM) and Photoluminescence (PL) as the analysis of film properties. The results of experiment, show that (112 ¡Â0) plane have more stringent conditions when generate of thin film, and easy to become the ring of electron diffraction with no-epitaxy .But finally we get a data what can generate a well a-plane ZnO thin film, the substrate temperature of 400 ¢X C, the sputtering time of 1 hour, Ar/O2 = 1.5. From the results of Photoluminescence, we find that there are zinc vacancies in ZnO thin film, probably there are too many oxygen atoms. While the heat treatment in nitrogen, zinc vacancies are reduced rapidly. Indicating that oxygen atoms within the film are reduced by nitrogen atoms or replace the position of the oxygen atoms.

The behaviors of high temperature corrosion on hot-dip aluminized on 9Cr-1Mo and 310 stainless steels when catalyzed by NaCl and cyclic heating environment were studied experimentally. The corrosion behavior and morphological development were investigated by weight gain kinetics, metallographs, depths of attack, metal losses, and X-ray analyses. The results of 310SS deposited with salt mixtures show that weight gain kinetics in simple oxidation reveals a steady-state parabolic rate law after 3 hr, while the kinetics with salt deposits display multi-stage growth rates. NaCl is the main corrosive specie in high-temperature corrosion involving mixtures of NaCl/Na2SO4 and is responsible for the formation of internal attack. Uniform internal attack is the typical morphology of NaCl-induced hot corrosion, while the extent of intergranular attack is more pronounced as the content of Na2SO4 in the mixture is increased. The thermal-cycling test results of 310SS deposited NaCl and coated 7wt%Si/93wt%Al show that the aluminized layers have good corrosion resistance during the first four cycles of testing, while degradation occurs after testing for five cycles. The reason for degradation of aluminized layers is attributed to the formation of interconnecting voids caused by aluminum inward diffusion, chloridation/oxidation cyclic reactions and the penetration of molten NaCl through the voids into the alloy substrate. The 9Cr-1Mo steels coated with 7wt%Si/93wt%Al oxidized at 750, 850, and 950°C in static air show that oxidation kinetics followed a parabolic rate law at 750 and 850 °C. The cracks propagated through the FexAly layer due to the growth of brittle FeAl2 and Fe2Al5 at 750 and 850°C. The voids condensed in the interface of intermetallics and substrate are attributed to the Kirkendall effect. At 950°C, the fast growing aluminide layer has a different expansion coefficient than oxide scale, leading to scale cracking, oxygen penetration, and internal oxidized, evidenced by a rapid mass gain.

No description available.

BRILHANTE, J. C. A. Contribuição de solutos orgânicos e inorgânicos no potencial osmótico de folhas de atriplex nummularia submetidas ao NaCl, SECA E PEG. 2006. 195 f. Dissertação (Mestrado em Agronomia/Fitotecnia) - Centro de Ciências Agrárias, Universidade Federal do Ceará, Fortaleza, 2006. / Submitted by Francisco Lacerda (lacerda@ufc.br) on 2014-07-15T19:39:06Z No. of bitstreams: 1 2006_dis_jcabrilhante.pdf: 1463347 bytes, checksum: 7f27bb350d9b7a07d32ec4ecef65c90f (MD5) / Approved for entry into archive by José Jairo Viana de Sousa(jairo@ufc.br) on 2014-07-16T20:06:44Z (GMT) No. of bitstreams: 1 2006_dis_jcabrilhante.pdf: 1463347 bytes, checksum: 7f27bb350d9b7a07d32ec4ecef65c90f (MD5) / Made available in DSpace on 2014-07-16T20:06:44Z (GMT). No. of bitstreams: 1 2006_dis_jcabrilhante.pdf: 1463347 bytes, checksum: 7f27bb350d9b7a07d32ec4ecef65c90f (MD5) Previous issue date: 2006 / Uma das características fisiológicas mais importantes das halófitas pertencentes ao gênero Atriplex é a enorme habilidade de acumular solutos orgânicos e inorgânicos com o intuito de se ajustar osmoticamente em condições de elevada salinidade e deficiência hídrica. Contudo estudos compreensivos sobre a contribuição relativa desses solutos inorgânicos e orgânicos no ajustamento osmótico de folhas dessas halófitas ainda são poucos explorados na literatura. Esse trabalho pretende pela primeira vez na literatura fazer um estudo detalhado, da participação e da contribuição relativa da maioria dos solutos orgânicos e inorgânicos no potencial osmótico de folhas de Atriplex nummularia, submetidas a concentrações crescentes de NaCl, ciclos sucessivos de seca e ao polietileno glicol (PEG). Para responder as questões acima mencionadas foram conduzidos três grandes experimentos seqüenciais. No primeiro experimento, mudas de Atriplex nummularia com quatro meses de idade, foram cultivadas em vasos de argila contendo como substrato areia, sendo irrigadas a cada dois dias com solução contendo concentrações crescentes de NaCl (0, 100, 200, 300 e 400 mmol L-1) durante 120 dias. O experimento foi realizado em condições de casa de vegetação. No segundo experimento, mudas de A. nummularia, com idade de 18 meses foram transplantadas para recipientes de polietileno contendo 5.0 kg de vermiculita, em condições de casa de vegetação, onde foram submetidas aos seguintes tratamentos (Controle; seca; NaCl + seca; NaCl) por três ciclos sucessivos de seca-reidratação (3 semanas) seguido de uma recuperação no final do último ciclo (após 48 h). No terceiro experimento, plântulas de A.nummularia, com idade de dois meses foram transplantadas para cultivo hidropônico em vasos plásticos com capacidade para 0,8 em sala de crescimento sob condições controladas onde sofrerão um pré-condicionamento com ou sem NaCl por duas semanas. Após foram submetidas aos seguintes tratamentos (controle; PEG; NaCl; NaCl + PEG). Em conclusão, os resultados da presente investigação demonstram que as plantas de Atriplex nummularia foram capazes de manter o seu crescimento mesmo em condições de alta salinidade, principalmente pela capacidade de manutenção de seu status hídrico. Os resultados também sugerem que a GB é o maior soluto orgânico envolvido com o ajustamento osmótico (AO) do citoplasma e que sua acumulação parece ser uma resposta adaptativa ao estresse provocado pelo NaCl. Em adição, o íons salinos Na+ e Cl- contribuíram para a maioria do AO das folhas submetidas ao NaCl. O impacto relativo do K+ sobre o AO das folhas foi reduzido consideravelmente com o aumento da dose externa de NaCl. Os resultados evidenciam também que o pré-condicionamento com NaCl influenciou positivamente no crescimento de Atriplex nummularia, em condições de seca, evidenciado pelo maior acúmulo de massa seca e melhor status hídrico das folhas. Dentre os solutos inorgânicos analisados, o Na+ e o Cl- foram os que mais contribuíram para a osmorregulação das folhas em condições de deficiência hídrica. Enquanto, GB foi o soluto orgânico mostrou o maior percentual de contribuição para o potencial osmótico. Entretanto os resultados mostraram que o pré-condicionamento das plântulas de Atriplex nummularia com NaCl não foram capazes de atenuar os efeitos induzidos pelo PEG.

El proceso de fabricación de embutidos curado-madurados es crucial para el desarrollo de unas características sensoriales óptimas siendo el aroma y sabor uno de los parámetros de calidad más importantes para los consumidores. Por ello, es de interés conocer los compuestos de gran potencia aromática que determinan la aceptación de dicho producto para así, diseñar nuevas estrategias tecnológicas que potencien el aroma de los embutidos curado-madurados. En vista de ello, la presente Tesis ha abordado el estudio de los compuestos volátiles con poder aromático mediante dos pasos críticos en la identificación de los compuestos como son la técnica de extracción y detección. Desde el punto de vista de la extracción de compuestos volátiles, se ha aplicado una técnica de extracción con disolventes (SAFE) y una de espacio de cabeza (SPME) a embutidos curado-madurados tradicionales. Además, se aplicaron técnicas olfatométricas (cromatografía de gases-olfatometría y “odour activity value”) con el fin de conocer qué técnica genera un extracto representativo del aroma del embutido. Desde el punto de vista de la detección de los compuestos volátiles, se emplearon diferentes detectores específicos cromatográficos (fotométrico de llama, nitrógeno-fósforo, olfatómetro) con el objetivo de facilitar la identificación, mediante cromatografía gases acoplada a espectrometría de masas y cromatografía de gases multidimensional, de compuestos volátiles minoritarios generados a lo largo del proceso de maduración. Por otro lado, es de gran interés para la industria cárnica satisfacer los intereses cardiosaludables de los consumidores. A este efecto, se ha determinado el efecto de la reducción de sal sobre la calidad de embutidos curado-madurados, asi como, la reducción de grasa y sal/grasa. Además, se ha empleado una cepa de Debaryomyces hansenii como alternativa para potenciar el aroma de dichos embutidos reformulados. De tal forma que se han estudiado los parámetros físico-químicos, microbiológicos y sensoriales de embutidos reducidos en sal y/o grasa inoculados con D. hansenii. Al igual que se ha estudiado la generación de los compuestos volátiles y su potencial aromático en dichos embutidos reformulados / Corral Silvestre, S. (2014). EFECTO DE LA REDUCCIÓN DEL CONTENIDO DE NaCl Y/O GRASA EN LA CALIDAD DE EMBUTIDOS CURADO-MADURADOS Y ESTUDIO DE NUEVAS ESTRATEGIAS PARA LA POTENCIACIÓN DEL AROMA [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/48477 / TESIS

L’évaporation d’eau chargée en sels fait partie des processus de dégradation d’un milieu poreux. Lors de l’évaporation, les sels vont s’accumuler à l’interface liquide-gaz, pouvant aller jusqu’à la cristallisation. Lors de la cristallisation, des contraintes importantes sont exercées sur la matrice solide du milieu poreux, ce qui à terme peut la détériorer.Les travaux présentés ici portent sur l’évaporation d’une solution de NaCl en situation de mèche et se focalisent sur les phénomènes de transport jusqu’à la cristallisation. Nous avons analysé le lien entre le transport de la vapeur, l’écoulement induit dans la solution par l’évaporation, le transport de sel depuis le réservoir de solution saline vers l’interface, et la cristallisation. Plusieurs études expérimentales ont été réalisées pour différentes configurations de mèche. Par ailleurs, nous avons aussi mis en place divers modèles numériques (approche continue 1D et 2D, réseaux de pores 2D et 3D).Une première étude sur une mèche saturée met en évidence l’influence de la cristallisation sur les différents transports. Les cristaux forment un nouveau milieu poreux, favorisant l’évaporation et générant un effet de pompage sur la solution saline. Une deuxième étude sur des mèches saturées a permis d’analyser l’influence de l’évaporation et des propriétés du milieu poreux sur la localisation et le temps d’apparition de la cristallisation. Les expériences montrent une cristallisation discrète à la surface des mèches, se formant préférentiellement dans les zones où l’évaporation est la plus intense. Dans le cas des milieux hétérogènes, la localisation de la cristallisation dépend des propriétés des milieux poreux formant les mèches (porosité et perméabilité).Finalement, la situation d’évaporation en milieu partiellement saturé est étudiée et montre aussi une cristallisation discrète. Nous avons constaté qu’une approche continue classique ne permet pas de prédire correctement la cristallisation en raison des hétérogénéités des fronts. Pour palier ce manque, des modèles de réseaux de pores ont été développés. Les résultats obtenus indiquent que pour une évaporation insuffisante, la cristallisation n’a jamais lieu à l’interface. Lorsque l’évaporation augmente, la proportion de fronts amenant à la cristallisation augmente. Lorsque l’évaporation devient suffisamment intense, la totalité des fronts atteignent la cristallisation. Les zones de cristallisation préférentielles le long des fronts sont identifiées et caractérisées. / The evaporation of water with dissolved salt is a main source of degradation of porousmedia. As water evaporates, dissolved salts accumulate under the liquid-gas interface, possibly reaching crystallization. As crystals grow, stresses can be generated andmay deteriorate pore walls. In this context, our study focuses onNaCl transport and crystallization processwhich result from evaporation inside or at the surface of the porousmedium. The link between vapour transport, brine flow, salt transport and crystallization, is studied with both experiments and numerical simulations (continuummodels and pore network models). A firstwork on saturatedwicks shows howthe growth of efflorescences affects the different transports occurring during evaporation. Efflorescences create a new porous medium which increases evaporation, and consequently salt transport through the wick, generating a "pumping effect". The influences of evaporation rate distributions and porous medium properties on crystallization are also analysed. Results showthat crystallization occurs in a discrete way over the surface of the saturated wicks, due to the porous medium disorder. In addition, it is found that efflorescences tend to grow preferentially in strong evaporating areas. For heterogeneousmedia, results show that crystallization occurs over the less permeable and the less porousmedium. A study of evaporation inside partially saturatedwicks also indicates discrete crystallization at the front. Classic continuum models can not predict accurately the crystallization over this kind of heterogeneous interface. Pore network models are more suitable to simulate transports with these large scale heterogeneities. Results show that depending on the global evaporation rate at the front, crystallization never occurs, may occur with a certain probability or always occurs. The relation between fronts structures, evaporation rate distribution and transports in the liquid phase, is analysed in order to understand and predict crystallization localization. These crystallization spots are then identified and characterized.