Efecto de estrés inducido con NaCI, Cu²? y Fe²? en biomasa, timol, carvacrol y prolina en orégano mexicano (lippia graveolens H.B.K.).

Tesis (Doctorado en Ciencias con Acentuación en Química de Productos Naturales) UANL, 2012.

Generación in situ del ion ferrato [Fe (VI)] cía fotocatalítica y electroquímica para la degradación del ácido 2,4-diclorofenoxiacético.

Tesis (Doctor en Química Analítica Ambiental) UANL, 2011.

Estudio de propiedades de magnesia sinterizada adicionando nanopartículas de óxido de hierro (Fe?O?), óxido de aluminio (AI?O?) y óxido de silicio (SiO?) para uso en ollas metalúrgicas secundarias.

Tesis (Doctor en Ingeniería de Materiales) UANL, 2013.

Aplicación de los catalizadores ZnO-Fe?O? y ZnO-Fe? en la degradación fotocatalítica solar de dicamba y 2,4-D.

Tesis (Doctor en Ciencias con orientación en Química Analítica Ambiental) UANL, 2013.

Comportement des systèmes de référence quantiques pour le moment cinétique

Le domaine des systèmes de référence quantiques, dont les dernière avancées sont brièvement présentées au chapitre 1, est extrêmement pertinent à la compréhension de la dégradation des états quantiques et de l’évolution d’instruments de mesures quantiques. Toutefois, pour arriver à comprendre formellement ces avancées et à apporter une contribution originale au domaine, il faut s’approprier un certain nombre de concepts physiques et mathématiques, in- troduits au chapitre 2. La dégradation des états quantiques est très présente dans le contrôle d’états utiles à l’informatique quantique. Étant donné que ce dernier tente de contrôler des sys- tèmes à deux états, le plus souvent des moments cinétiques, l’analyse des systèmes de référence quantiques qui les mesurent s’avère opportune. Puisque, parmi les plus petits moments ciné- tiques, le plus connu est de s = 1 et que son état le plus simple est l’état non polarisé, l’étude 2 du comportement d’un système de référence mesurant successivement ce type de moments ci- nétiques constitue le premier pas à franchir. C’est dans le chapitre 3 qu’est fait ce premier pas et il aborde les questions les plus intéressantes, soit celles concernant l’efficacité du système de référence, sa longévité et leur maximum. La prochaine étape est de considérer des états de moments cinétiques polarisés et généraux, étape qui est abordée dans le chapitre 4. Cette fois, l’analyse de la dégradation du système de référence est un peu plus complexe et nous pouvons l’inspecter approximativement par l’évolution de certains paramètres pour une certaine classe d’états de système de référence. De plus, il existe une interaction entre le système de référence et le moment cinétique qui peut avoir un effet sur le système de référence tout à fait comparable à l’effet de la mesure. C’est cette même interaction qui est étudiée dans le chapitre 5, mais, cette fois, pour des moments cinétiques de s = 1. Après une comparaison avec la mesure, il devient manifeste que les ressemblances entre les deux processus sont beaucoup moins apparentes, voire inexistantes. Ainsi, cette ressemblance ne semble pas générale et semble accidentelle lorsqu’elle apparaît.

Les perceptions de la sexualité et les relations de couple de femmes haïtiennes immigrantes au Québec : pour une exploration des rapports hommes femmes en Haïti

Ce mémoire a étudié les perceptions de femmes haïtiennes vivant au Québec depuis moins de cinq ans de leurs relations sexuelles avec les hommes et de leurs rapports de couple. Après avoir opté pour une méthodologie de recherche qualitative, la théorie féministe intersectionnelle a été retenue comme cadre d’analyse. Des entretiens individuels semi-dirigés ont été menés auprès de 9 femmes haïtiennes, âgées de 18 à 60 ans et ayant immigré au Québec depuis moins de cinq ans. Les perceptions des femmes de la sexualité ont été appréhendées comme étant un ensemble de discours et de pratiques inter reliés, qui se construit dès l’enfance, et qui reproduit les types de rapports inégalitaires entre hommes et femmes qui existent dans la société haïtienne et dans leur couple. Ces rapports inégalitaires sont véhiculés entre les générations à travers la plupart des institutions sociales comme la famille, l’école, la culture, la législation. Ce processus de construction des perceptions de la sexualité est également influencé par des enjeux socio-économiques et de pouvoir. Les résultats de cette recherche permettent de disposer de données scientifiques sur la sexualité des femmes et les rapports de couple en Haïti et l’influence du processus migratoire. Ces résultats soulignent également la nécessité pour le travail social haïtien d’encourager le développement de l’empowerment économique des femmes et leur participation aux débats actuels de la société sur l’évolution de la condition féminine.

La Réserve fédérale, le régime monétaire international et la justice économique

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Zeolite Encapsulated Complexes Of Fe,Co,Ni,Cu And Pd:Synthesis , Characterization And Catalysis-2003

This thesis deals with the synthesis, characterization and catalysis activity studies of some zeolite encapsulated complexes. Encapsulation inside the zeolite cages makes the catalysts more stable. Further, the framework prevents the complexes from dimerising. Catalysis by metal complexes encapsulated in the cavities of zeolites and other molecular sieves has many features of homogeneous, heterogenous and enzymatic catalysis. Serious attempts has been made to gain product selectivity in catalysis .The catalytic activity shown by the encapsulated complexes can be correlated to the structure of the active site inside the zeolite pore. It deals with the studies on the partial oxidation of benzyl alcohol to benzaldehyde. The oxidatio was carried out using hydrogen peroxide as oxidant in presence of PdYDMG and CuYSPP as catalysts. The product (benzaldehyde) was detected using TLC and confirmed using GC.The catalytic activity of the complexes was tested for oxidation under various conditions. The operating conditions like the amount of the catalyst, reaction time, oxidant to substrate ratio, reaction temprature, and solvents have been optimized. No further oxidation products were obtained on continuing the reaction for four hours beyond the optimum time. Maximum conversion was obtained at room temperature and the percentage conversion decreased with increase in temperature. Activity was found to be dependent on the solvent used. With increasing awareness about the dangers of environmental degradation, research in chemistry is getting increasing geared to the development of “green chemistry,” by designing environmentally friendly products and processes that bring down the generation and use of hazardous substances.

Removal of Fe(III) using a polystyrene anchored Schiff base

Salicylaldehyde Schiff base of amino-methylated polystyrene has been developed as a novel reagent for the removal of Fe(III) from solutions. The selectivity of the metal ion uptake over a wide range of different concentrations of metal ion, effect of pH, ligand concentration and the influence of other foreign ions were studied. A very good selectivity was achieved for the removal of the ion. It was found that 0.01 g of the ligand was sufficient to achieve about 96% removal of the metal ion in terms of concentration (ppm) from a 30 ppm solution in acidic pH.

Fabrication of thin films and nano columnar structures of Fe-Ni amorphous alloys and modification of its surface properties by thermal annealing and swift heavy ion irradiation for tailoring the magnetic properties

Department of Physics, Cochin University of Science and Technology

Surface acidity and catalytic activity of mixed Fe-Al and Cr-Al pillared montmorillonites

The incorporation of transition metal oxide pillars such as those of iron and chromium along with Al2O3, pillars within the interlayers of a montmorillonite clay is investigated. The surface acidity of these catalysts has been evaluated for the first time employing the equilibrium adsorption of an electron donor, perylene, and the results are compared with those obtained by temperature programmed desorption of ammonia. The principle is based on the ability of a catalyst surface site to accept a single electron from an electron donor like perylene to form charge transfer complexes and the amount of adsorbed species is measured quantitatively by UV-vis spectroscopy. Fina1ly, an attempt has been made to correlate the acidity determined by the two independcnt methods and the catalytic activity of present systems in the benzoylation of toluene with benzoyl chloride. Incorporation of Fe and Cr has changed the properties of AI pitlared montmorillonite. Fe pillared systems have been found to be vcry good catalysts for benzoylation reaction

Coverage effects on the magnetism of Fe/MgO(001) ultrathin films

Different aspects of the structure-magnetism and morphology-magnetism correlation in the ultrathin limit are studied in epitaxial Fe films grown on MgO(001). In the initial stages of growth the presence of substrate steps, intrinsically higher than an Fe atomic layer, prevent the connection between Fe islands and hence the formation of large volume magnetic regions. This is proposed as an explanation to the superparamagnetic nature of ultrathin Fe films grown on MgO in addition to the usually considered islanded, or Vollmer-Weber, growth. Using this model, we explain the observed transition from superparamagnetism to ferromagnetism for Fe coverages above 3 monolayers (ML). However, even though ferromagnetism and magnetocrystalline anisotropy are observed for 4 ML, complete coverage of the MgO substrate by the Fe ultrathin films only occurs around 6 ML as determined by polar Kerr spectra and simulations that consider different coverage situations. In annealed 3.5 ML Fe films, shape or configurational anisotropy dominates the intrinsic magnetocrystalline anisotropy, due to an annealing induced continuous to islanded morphological transition. A small interface anisotropy in thicker films is observed, probably due to dislocations observed at the Fe¿MgO(001) interface.

Evidence of extended orientational order in amorphous Fe/Sm thin films

Amorphous thin films of Fe/Sm, prepared by evaporation methods, have been magnetically characterized and the results were interpreted in terms of the random magnets theory. The samples behave as 2D and 3D random magnets depending on the total thickness of the film. From our data the existence of orientational order, which greatly influences the magnetic behavior of the films, is also clear.

Ab initio study of MF2 (M=Mn, Fe, Co, Ni) rutile-type compounds using the periodic unrestricted Hartree-Fock approach

The ab initio periodic unrestricted Hartree-Fock method has been applied in the investigation of the ground-state structural, electronic, and magnetic properties of the rutile-type compounds MF2 (M=Mn, Fe, Co, and Ni). All electron Gaussian basis sets have been used. The systems turn out to be large band-gap antiferromagnetic insulators; the optimized geometrical parameters are in good agreement with experiment. The calculated most stable electronic state shows an antiferromagnetic order in agreement with that resulting from neutron scattering experiments. The magnetic coupling constants between nearest-neighbor magnetic ions along the [001], [111], and [100] (or [010]) directions have been calculated using several supercells. The resulting ab initio magnetic coupling constants are reasonably satisfactory when compared with available experimental data. The importance of the Jahn-Teller effect in FeF2 and CoF2 is also discussed.

On the Tailoring of Magnetic Properties of Fe-Based Alloy Thin Films by Swift Heavy Ion Irradiation and Thermal Annealing

The development of new materials has been the hall mark of human civilization. The quest for making new devices and new materials has prompted humanity to pursue new methods and techniques that eventually has given birth to modern science and technology. With the advent of nanoscience and nanotechnology, scientists are trying hard to tailor materials by varying their size and shape rather than playing with the composition of the material. This, along with the discovery of new and sophisticated imaging tools, has led to the discovery of several new classes of materials like (3D) Graphite, (2D) graphene, (1D) carbon nanotubes, (0D) fullerenes etc. Magnetic materials are in the forefront of applications and have beencontributing their share to remove obsolescence and bring in new devices based on magnetism and magnetic materials. They find applications in various devices such as electromagnets, read heads, sensors, antennas, lubricants etc. Ferromagnetic as well as ferrimagnetic materials have been in use in the form of various devices. Among the ferromagnetic materials iron, cobalt and nickel occupy an important position while various ferrites finds applications in devices ranging from magnetic cores to sensors.