Desarrollo de membranas polméricas de nano-fibras, micro-fibras y fibra hueca para la desalación por destilación en membrana

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Físicas, Departamento de Física Aplicada I (Termología), leída el 26-09-2014Depto. de Estructura de la Materia, Física Térmica y ElectrónicaFac. de Ciencias FísicasTRUEunpu

Mapeo de redes de fracturas mediante imágenes Landsat-8 OLI en la zona minera de Jbel Tijekht en el Anti-Atlas oriental de Marruecos

Jbel Tijekht is one of the most important geological structures of the Ougnat-Ouzina ridge in the Eastern Anti-Atlas. This crescent-shaped massif was affected by a network fractures that is visible at different scales. It is particularly rich in numerous mineralized veins of barite, and is associated with other minerals (e.g. pyrite, chalcopyrite, sphalerite and galena). In order to study fracture systems in the mining zone of Jbel Tijekht, we opted for a combination of remote sensing and field investigation that became an important tool for fracture mapping and mineral exploration. This work presents a methodological approach to detect structural lineaments. For this purpose, various techniques were applied to the Landsat 8 image to improve the visibility of linear structures. After the radiometric and atmospheric corrections, the colors composites and directional filters applied to the Principal component (PC1) allow for the establishment of a lineaments map of Jbel Tijekht. The validation and the correction of lineaments are based on preexisting documents combined with field observations. Statistical analysis of the lineament map allows for identification of at least three directional fracture systems with average NS, NE-SW, and ENE-WSW orientations. NS and NE-SW systems show a high density in the largest part of the study area. These results clearly overlap different tectonic structures and existing veins. It allowed for the establishment of a geological link between lithology, fractures systems and mineralization. The fracture density can be attributed to the last variscan brittle phases, reflecting the rheology of rock units; the high fracture density is observed in competent rocks such as the Tabanit sandstones. These zones constitute a favorable area for mineralization deposits.El Jbel Tijekht es una de las estructuras geológicas más importantes de la cordillera de Ougnat-Ouzina en el Anti-Atlas Oriental. Este macizo en forma de media luna fue afectado por una red de fracturas que es visible a diferentes escalas. Es particularmente rico en vetas mineralizadas de barita y está asociado con otros minerales (por ejemplo, pirita, calcopirita, esfalerita y galena). Para estudiar los sistemas de fracturas en la zona minera de Jbel Tijekht, optamos por una combinación de teledetección e investigación de campo que se convirtió en una importante herramienta para la cartografía de las fracturas y la exploración de minerales. Este trabajo presenta un enfoque metodológico para detectar los lineamientos estructurales. Para ello, se aplicaron diversas técnicas a la imagen del Landsat 8 para mejorar la visibilidad de las estructuras lineales. Tras correcciones radiométricas y atmosféricas, los colores compuestos y los filtros direccionales aplicados al componente principal (PC1) se pudo establecer un mapa de lineamientos para Jbel Tijekht. La validación y corrección de estos lineamientos se basan en documentos preexistentes combinados con observaciones de campo. El análisis estadístico del mapa de lineamientos permite la identificación de al menos tres sistemas de fractura direccional con orientaciones promedio NS, NE-SW y ENE-WSW. Los sistemas NS y NE-SW muestran una alta densidad en la mayor parte del área de estudio. Estos resultados claramente se superponen a diferentes estructuras tectónicas y a las vetas existentes. Esto permitió establecer un vínculo geológico entre la litología, los sistemas de fracturas y la mineralización. La densidad de fracturas puede atribuirse a las últimas fases de fragilidad del orógeno varisco, lo que refleja la reología de las unidades de roca; la alta densidad de fractura se observa en las rocas competentes como las areniscas de Tabanit. Estas zonas constituyen un área favorable para los depósitos de mineralización

Anisotropie de la Susceptibilité Magnétique : Théorie et exemples d'application pour la mis en évidence de paléocirculations de fluides.

21-23 mai 2008L'Anisotropie de la Susceptibilité Magnétique (ASM) est utilisée depuis une trentaine d'années pour déterminer la fabrique des roches (Hrouda, 1982 ; Tarling et Hrouda, 1993). Elle est aussi largement utilisée lors de travaux de géologie structurale en particulier ceux relatifs à la détermination des structures des plutons granitiques (Talbot et al., 2005). L'objectif de cette communication est de montrer, à partir de deux études de cas, comment le couplage entre l'ASM et l'analyse texturale permet de retracer le(s) trajet(s) de circulation des paléo-fluides

Prospección minera de la mineralización de óxidos de Fe-Mn-Pb en Jbel Skindis (Alto Atlas Oriental, Marruecos) basada en teledetección y SIG

In recent years, remote sensing has had a prominent place in mineral exploration programs given its potential to identify alteration minerals, such as clay and hydroxyl minerals. Those minerals represent significant guides to mineral deposits considering their potential to host valuable concentrations of base metal elements. This work focuses on Fe-Mn-Pb mineral deposits within the Jbel Skindis area as a case study to illustrate the application of remote sensing images and GIS systems to highlight prospective zones and to extract information on ore-controlling factors using image enhancement and integration methods. Field observations and XRD data showed that the main remotely sensed alteration anomalies are characterized by oxides and hydroxides. Based on those indicative minerals, a mapping using Aster L1T and Landsat 8 OLI data was done: the 5/4 ratio highlighted gossans zones and the RGB combination (4/6, 2/1, 3/2) accentuates the hydrothermally altered areas. The lineament map extracted from Sentinel 2A and Landsat imagery allowed the reconstitution of the megafracture network that affected the region. The multi-criteria analysis of these satellite-derived data along with available geological data outcomes to delineate prospective zones in the study area, were found to be in highly fractured areas developing gossans and Fe rich alteration. Verified via field survey, this approach was successfully applied to the Jbel Skindis area to rapidly delineate oxidized ore outcrops. This provides a remote sensing model for future prospecting efforts for similar mineral deposits both in the Eastern High-Atlas province and in other similar areas.En los últimos años, la teledetección ha ocupado un lugar destacado en los programas de exploración minera dada su utilidad para identificar minerales de alteración, como la arcilla y los hidróxidos. Estos minerales son guías significativas para encontrar depósitos minerales que albergan concentraciones valiosas de metales base. Este trabajo se centra en las mineralizaciones de Fe-Mn-Pb dentro del área de Jbel Skindis consideradas como un zona de estudio para ilustrar la aplicación de imágenes de teledetección y de un sistema SIG para delinear zonas de interés para la exploración minera y extraer información sobre los factores que controlan las concentraciones de metales utilizando tratamiento de datos satélites e integración de imágenes. De acuerdo con las observaciones de campo y los datos DRX las principales anomalías de alteración deducidas del tratamiento de datos satélite se caracterizan por óxidos e hidróxidos. En base a estos minerales, se realizó un mapeo utilizando los datos de Aster L1T y Landsat 8 OLI: la relación 5/4 resalta las zonas de Gossans mientras la combinación RGB (4/6, 2/1, 3/2) señala las áreas alteradas. El mapa de lineamientos extraído de las imágenes de Sentinel 2A y Landsat permitió reconstituir la red de megafracturas que afectó a la región. El acoplamiento entre un análisis multi-criterio de los datos derivados de satélites y los datos geológicos disponibles, permitió delinear zonas de interés para la exploración minera en el área de estudio. Estas zonas corresponden a áreas altamente fracturadas en las cuales se desarrollan gossans y alteración rica en Fe. Este enfoque junto con un control a través de un estudio de campo, se aplicó con éxito en el área de Jbel Skindis para delinear rápidamente los afloramientos de mineralizaciones oxidadas. Esto proporciona un modelo de teledetección para futuros esfuerzos de prospección de depósitos minerales similares tanto en la provincia oriental del Alto Atlas como en otras áreas similares

Non Typhoidal Salmonella in food products

Food-Borne Diseases (FDB) include a large number of diseases resulting from the ingestion of food contaminated with microorganism’s toxins or other chemicals. One of the most common FBD is Salmonellosis, a zoonosis caused by Salmonella, considered as one of the four leading causes of zoonotic diseases in the world. The present review aims to collect and update information about Salmonella and its prevalence in food products worldwide based on published research studying this pathogenic organism in addition to a general view of regulations implemented by the World Health Organizations and recommendations guidelines adapted by food industries. After describing Salmonella and its different bacterial, biochemical and environmental characteristics, several research have been analyzed to determine prevalence of Salmonella in different countries to determine the most important sources of contamination of food products. The first source of contamination found is poultry products and raw egg products due to ease of their contamination by Salmonella, while contamination of other food products was variable. Severe effects of Salmonella prove the importance of having regulations to limit the negative consequences of the emergence of Salmonella. Keywords: Salmonella, Human Salmonellosis, Prevalence, food produc

Assessment of the environmental impact of polymeric membrane production

Polymeric membranes are important in advanced separation technologies because of their high efficiency and low environmental impact. However, procedures for membrane production are far from sustainable and environmentally friendly. This work presents a life cycle assessment of the environmental impact of fabricating 1000 m(2) of hollow fiber polymeric membranes. Membrane materials considered include the most popular fossil- and bio-based polymers in current use, i.e., polysulfones, polyvinylidene fluoride, and cellulose acetate. Solvents considered for use in polymer dope solution included polar aprotic solvents (N-Methyl-2-pyrrolidone, N, N-dimethylacetamide, and dimethylformamide) that are widely used in industry and an alternative green solvent (ethylene carbonate). The impacts of membrane production on global warming, marine ecotoxicity, human carcinogenic and non-carcinogenic toxicity, land use potential, and fossil resource scarcity were analyzed. Additionally, the impact on the sustainability and environmental cost of membrane production resulting from replacing fossil-based polymers with bio-based polymers or substituting toxic solvents with a green alternative was investigated. Hot spots in the membrane production process were identified, and measures to reduce the environmental impact of membrane production were proposed

Track of fluid paleocirculation in dolomite host rock at regional scale by the Anisotropy of Magnetic Susceptibility (AMS): An example from Aptian carbonates of La Florida (Northern Spain)

International audienceThe present study aims to apply the AMS method (Anisotropy of Magnetic Susceptibility) at a regional scale to track the fluid circulation direction that has produced an iron metasomatism within pre-existing dolomite host rock. The Urgonian formations hosting the Zn-Pb mineralizations in La Florida (Cantabria, northern Spain) have been taken as target for this purpose. Sampling was carried out, in addition to ferroan dolomite host rock enclosing the Zn-Pb mineralizations, in dolomite host rock and limestone to make the comparison possible between magnetic signals from mineralized rocks, where fluid circulation occurred, and their surrounding formations. AMS study was coupled with petrofabric analysis carried out by texture goniometry, Scanning Electron Microscopy (SEM) observations and also Shape Preferred Orientation (SPO) statistics. SEM observations of ferroan dolomite host rock illustrate both bright and dark grey ribbons corresponding respectively to Fe enriched and pure dolomites. SPO statistics applied on four images from ferroan dolomite host rock give a well defined orientation of ribbons related to the intermediate axis of magnetic susceptibility K2. For AMS data, two magnetic fabrics are observed. The first one is observed in ferroan dolomite host rock and characterised by a prolate ellipsoid of magnetic susceptibility with a vertical magnetic lineation. The magnetic susceptibility carrier is Fe-rich dolomite. These features are probably acquired during metasomatic fluid circulations. In Fe-rich dolomite host rock, ‹c› axes are vertical. As a rule, (0001) planes (i.e. planes perpendicular to ‹c› axes) are isotropic with respect to crystallographic properties. So, the magnetic anisotropy measured in this plane should reflect crystallographic modification due to fluid circulation. This is confirmed by the texture observed using the SEM. Consequently, AMS results show a dominant NE-SW elongation interpreted as the global circulation direction and a NW-SE secondary elongation that we have considered as sinuosities of the fluid trajectory. The second type of magnetic fabric is essentially observed in the limestone and characterised by an oblate form of the ellipsoid of magnetic susceptibility, a horizontal magnetic foliation and mixed magnetic susceptibility carriers. It is interpreted as a sedimentary fabric

Apport de Mycobacterium vaccae dans la Prévention et le Traitement de Certaines Maladies : Revue Bibliographique

In recent decades, the role of Mycobacterium vaccae, a nonpathogenic bacterium living naturally in the soil, as a modulator of immunity has been evoked by several investigations. Thus, its contribution in the prevention and treatment of many diseases such as tuberculosis, leprosy, allergy and asthma in which immunity occupies a large place has been highlighted. Such diseases present a burden on human health and require for their treatment and surveillance the administration of drugs with a plethora of side effects. In this sense, the effect of Mycobacterium vaccae preparations administered in different forms has been evaluated in murine models or in clinical trials. It seems, in the case of inflammatory diseases for example, that this mycobacterium enhances immunity by increasing the T helper 1 (Th1) immune response, inducing regulatory T cells, eventually leading to suppression of TH2-like cells and their mediators involved in the appearance of the inflammation which leads, therefore, to the attenuation of the pathological symptoms. Subsequently, this review aims to expose the impact of the bacterium in question to fight against certain diseases.Ces dernières décennies, le rôle de Mycobacterium vaccae, une bactérie non pathogène et vivant naturellement dans le sol, comme modulatrice de l’immunité a été évoqué par plusieurs investigations. Ainsi, son apport dans la prévention et le traitement de nombreuses maladies telles que la tuberculose, la lèpre, l’allergie et l’asthme dans lesquelles l'immunité occupe une grande place a été mis en évidence. De telles pathologies présentent un fardeau pour la santé humaine et exigent pour leur traitement et surveillance l’administration des médicaments possédant une pléthore d’effets secondaires. Dans ce sens, l’effet des préparations à la base de Mycobacterium vaccae administrées sous différentes formes a été évalué sur des modèles murins ou dans des essaies cliniques. Il semble, dans le cas des maladies inflammatoires par exemple, que cette mycobactérie renforce l’immunité par l’augmentation de la réponse immunitaire de type T auxiliaires 1 (Th1), l’induction des lymphocytes T régulateurs, menant par la suite à la suppression de cellules de type TH2 et leurs médiateurs impliqués dans l’apparition de l’inflammation ce qui entraine, par conséquent, l’atténuation des symptômes pathologiques. Subséquemment, la présente synthèse bibliographique a pour objectif d’exposer l’impact de la bactérie en question pour lutter contre certaines maladies

A case study of the internal structures of gossans and weathering processes in the Iberian Pyrite Belt using magnetic fabrics and paleomagnetic dating

International audienceIn the Rio Tinto district of the Iberian Pryrite Belt of South Spain, the weathering of massive sulfide bodies form iron caps, i.e., true gossans and their subsequent alteration and re-sedimentation has resulted in iron terraces, i.e., displaced gossans. To study the stucture and evolution of both types of gossans, magnetic investigations have been carried out with two foci: (1) the characterisation and spatial distribution of magnetic fabrics in different mineralised settings, including massive sulfides, gossans, and terraces, and (2) paleomagnetic dating. Hematite has been identified as the suceptibility carrier in all sites and magnetic fabric investigation of four gossans reveals a vertical variation from top to bottom, with: (1) a horizontal foliation refered to as "mature" fabric in the uppermost part of the primary gossans, (2) highly inclined or vertical foliation interpreted as "immature" fabric between the uppermost and lowermost parts, and (3) a vertical foliation interpreted to be inherited from Hercynian deformation in the lowermost part of the profiles. In terraces, a horizontal foliation dominates and is interpreted to be a "sedimentary" fabric. Rock magnetic studies of gossan samples have identified goethite as the magnetic remanence carrier for the low-temperature component, showing either a single direction close to the present Earth field (PEF) direction or random directions. Maghemite, hematite, and occasionally magnetite are the remanence carriers for the stable high-temperature component that is characterized by non PEF directions with both normal and reversed magnetic polarities. No reliable conclusion can be yet be drawn on the timing of terrace magnetization due to the small number of samples. In gossans, the polarity is reversed in the upper part and normal in the lower part. This vertical distribution with a negative reversal test suggests remanence formation during two distinct periods. Remanence in the upper parts of the gossans is older than in the lower parts, indicating that the alteration proceeded from top to bottom of the profiles. In the upper part, the older age and the horizontal "mature" fabric is interpreted to be a high maturation stage of massive sulfides' alteration. In the lower part, the age is younger and the inherited "imature" vertical Hercynian fabric indicates a weak maturation stage. These two distinct periods may reflect changes of paleoclimate, erosion, and/or tectonic motion