1000 resultados para Cromatografía del gas
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Hydatidosis is a zoonosis of worldwide distribution produced mainly by the metacestode Echinococcus granulosus. In Argentina, its distribution reaches endemic levels. The aims of this investigation were to contribute to the knowledge of hydatidosis in the southeast of Buenos Aires province, study its evolution at the Interzonal General Hospital for Acute Diseases between 1992 and 2002 and discuss its importance. Clinical records of operated and/or diagnosed patients were reviewed with regard to this disease. One hundred and twenty cases were analyzed. Among the patients, 56.7% were women. The average age was 42.2+16.8 years. 68.3% lived in urban areas. In 75% of the cases, ultrasonography was used. Hepatic location was most frequently seen. 89.2% received surgical treatment. Albendazole was used for 19 patients. The mean length of hospital stay was 16 days. We conclude that this zoonosis is a disease that generates high costs in medical care and for this reason more epidemiological studies should be carried out and public health authorities should implement control and prevention strategies in the region.
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In this work, a volumetric unit previously assembled by the research group was upgraded. This unit revamping was necessary due to the malfunction of the solenoid valves employed in the original experimental setup, which were not sealing the gas properly leading to erroneous adsorption equilibrium measurements. Therefore, the solenoid valves were substituted by manual ball valves. After the volumetric unit improvement its operation was validated. For this purpose, the adsorption equilibrium of carbon dioxide (CO2) at 323K and 0 - 20 bar was measured on two different activated carbon samples, in the of extrudates (ANG6) and of a honeycomb monolith (ACHM). The adsorption equilibrium results were compared with data previously measured by the research group, using a high-pressure microbalance from Rubotherm GmbH (Germany) – gravimetric. The results obtained using both apparatuses are coincident thus validating the good operation of the volumetric unit upgraded in this work. Furthermore, the adsorption equilibrium of CO2 at 303K and 0 - 10 bar on Metal-Organic Frameworks (MOFs) Cu-BTC and Fe-BTC was also studied. The CO2 adsorption equilibrium results for both MOFs were compared with the literature results showing good agreement, which confirms the good quality of the experimental results obtained in the new volumetric unit. Cu-BTC sample showed significantly higher CO2 adsorption capacity when compared with the Fe-BTC sample. The revamping of the volumetric unit included a new valve configuration in order to allow testing an alternative method for the measurement of adsorption equilibrium. This new method was employed to measure the adsorption equilibrium of CO2 on ANG6 and ACHM at 303, 323 and 353K within 0-10 bar. The good quality of the obtained experimental data was testified by comparison with data previously obtained by the research group in a gravimetric apparatus.
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Among the vectors of Chagas disease, Triatoma patagonica is a species in the process of adaptation to the human environment. However, its vector competence is not well known. This study had the aim of evaluating and comparing feeding and defecation patterns among fifth-instar nymphs of Triatoma patagonica and Triatoma infestans that were fed ad libitum. The results showed that nymphs of Triatoma patagonica had a feeding pattern similar to that of Triatoma infestans. Sixty nine percent and 58% of nymphs of Triatoma patagonica and Triatoma infestans, respectively, produced their first defecation within five minutes after being fed. Triatoma patagonica defecated during feeding, with an average time until first defecation that was shorter than that of Triatoma infestans (3.4 and 6.2 min, respectively). The nymphs of Triatoma patagonica were capable of defecating during or immediately after feeding.
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La Tesi è incentrata sulle figure di D. Dinis e Isabel d’Aragona, reali del Portogallo (fine del XIII-prima metà del XIV secolo), e si focalizza sul processo di creazione e trasmissione della memoria, elaborato e messo in atto dai sovrani nel corso della loro esistenza. L’atto finale di questo annoso processo fu la realizzazione dei loro monumenti funebri creati per essere conservati nella chiesa del monastero cistercense di São Bernardo e São Dinis di Odivelas, la tomba del re, e nella chiesa del monastero di Santa Clara e Santa Isabel di Coimbra, quella della regina. Infatti, in modo del tutto inedito rispetto alla tradizione precedente, i re commissionarono e videro in vita realizzati i sepolcri che avrebbero dovuto preservare la loro memoria per l’Eternità. Essi furono concepiti a priori come parte integrante del progetto monumentale più vasto costituito dagli edifici monastici che li avrebbero dovuti custodire. In tale prospettiva, è stata rivolta particolare attenzione alla storia del monastero di Odivelas, assurto a pantheon della Monarchia, seppure per breve tempo, e al monastero di Coimbra, ultima dimora della regina Isabel una volta fallito il progetto del pantheon reale a causa della guerra civile che sconvolse il regno del Portogallo tra il 1319 e il 1324. Oltre ai sepolcri reali, sono state prese in esame alcune opere di architettura e di scultura legate alla committenza regia – in coppia o individualmente –, in particolare tre tombe coeve, due delle quali destinate ad altrettanti membri della famiglia reale. All’interno di questa Tesi, i monumenti funebri esaminati sono stati considerati non solo come strumento privilegiato per la commemorazione del defunto, ma anche come forieri di un preciso messaggio indirizzato a tutti coloro che avrebbero fruito della loro visione. Così, l’iconografia dei sepolcri è stata analizzata alla luce della spiritualità e della religiosità dei sovrani, oltre che dal punto di vista stilistico e formale. Come premessa allo studio prettamente storico-artistico, inizialmente sono stati approfonditi i rapporti tra il regno del Portogallo e la Sede Apostolica al momento dell’ascesa al trono di D. Dinis e, successivamente, il tema della guerra civile che vide contrapporsi il re e il principe, il futuro Alfonso IV. A questo scopo, integra la Tesi un’Appendice documentaria che presenta 64 documenti, la maggior parte dei quali inediti. Questo studio intende dimostrare come il Portogallo dionisino si collochi pienamente nell’orbita culturale mediterranea e proporre nuove affermazioni, considerazioni ed ipotesi rispetto ai re Dinis e Isabel, alle loro vicende storiche e personali e alla memoria di sé che vollero trasmettere ai posteri.
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This work is divided into two distinct parts. The first part consists of the study of the metal organic framework UiO-66Zr, where the aim was to determine the force field that best describes the adsorption equilibrium properties of two different gases, methane and carbon dioxide. The other part of the work focuses on the study of the single wall carbon nanotube topology for ethane adsorption; the aim was to simplify as much as possible the solid-fluid force field model to increase the computational efficiency of the Monte Carlo simulations. The choice of both adsorbents relies on their potential use in adsorption processes, such as the capture and storage of carbon dioxide, natural gas storage, separation of components of biogas, and olefin/paraffin separations. The adsorption studies on the two porous materials were performed by molecular simulation using the grand canonical Monte Carlo (μ,V,T) method, over the temperature range of 298-343 K and pressure range 0.06-70 bar. The calibration curves of pressure and density as a function of chemical potential and temperature for the three adsorbates under study, were obtained Monte Carlo simulation in the canonical ensemble (N,V,T); polynomial fit and interpolation of the obtained data allowed to determine the pressure and gas density at any chemical potential. The adsorption equilibria of methane and carbon dioxide in UiO-66Zr were simulated and compared with the experimental data obtained by Jasmina H. Cavka et al. The results show that the best force field for both gases is a chargeless united-atom force field based on the TraPPE model. Using this validated force field it was possible to estimate the isosteric heats of adsorption and the Henry constants. In the Grand-Canonical Monte Carlo simulations of carbon nanotubes, we conclude that the fastest type of run is obtained with a force field that approximates the nanotube as a smooth cylinder; this approximation gives execution times that are 1.6 times faster than the typical atomistic runs.
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In the field of energy, natural gas is an essential bridge to a clean, low carbon, renewable energy era. However, natural gas processing and transportation regulation require the removal of contaminant compounds such as carbon dioxide (CO2). Regarding clean air, the increasing atmospheric concentrations of greenhouse gases, specifically CO2, is of particular concern. Therefore, new costeffective, high performance technologies for carbon capture have been researched and the design of materials with the ability to efficiently separate CO2 from other gases is of vital importance.(...)
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Shape memory alloys are characterized by the ability of recovering their initial shape after being deformed and by superelasticity. Since the discovery of these alloys, a new field of interest emerged not only for the scientific community but also to many industries. However, these alloys present poor machinability which constitute a constrain in the design of complex components for new applications. Thus, the demand for joining techniques able to join these alloys without compromising their properties became of great importance to enlarge the complexity of existing applications. Literature shows that these alloys are joined mainly using laser welding. In the present study, similar NiTi butt joints, were produced using TIG welding. The welds were performed in 1.5 mm thick plates across the rolling direction. A special fixture and gas assist device was designed and manufactured. Also a robot arm was adapted to accommodate the welding torch to assure the repeatability of the welding parameters. Welds were successfully achieved without macroscopic defects, such as pores and distortions. Very superficial oxidation was seen on the top surface due to insufficient shielding gas flow on the weld face. The welded joints were mechanically tested and structurally characterized. Testing methods were used to evaluate macro and microstructure, as well as the phase transformation temperatures, the mechanical single and cyclic behaviour and the shape recovery ability. Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), microhardness measurements were techniques also used to evaluate the welded joints. A depletion in Ni in the fusion zone was seen, as well as a shift in Ms temperature. For strain values of 4% the accumulated irrecoverable strain was of about 30% and increased with the strain imposed during cycling. Nevertheless, a complete recovery of initial shape was observed when testing the shape memory effect on a dedicated device that introduces a deformation of 6.7%. That is, the welding procedure does not remove the ability of the specimens to recover their initial shape.
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El presente informe tiene como propósito definir las bases esenciales del coaching y su posible adecuación al campo educativo, en una época en la que el alumnado parece un poco «desconectado» de la Escuela, no entendiendo a priori su importancia para su propio crecimiento personal y enriquecimiento profesional en el futuro. En el primer capítulo, empezaremos por la definición del concepto de coaching, su origen y principios fundamentales. En el segundo, el foco se centrará en la importancia de la aplicación de las bases del coaching en el proceso enseñanza-aprendizaje, el papel fundamental del profesor coach y sus competencias. En el tercero capítulo se dará cuenta de algunas herramientas internas (asociadas a la propia capacidad del profesor coach) y externas (aquellas que puede utilizar el docente al echar mano de recursos externos a él mismo) importantes en un proceso de coaching. En el cuarto capítulo, se procederá a la experiencia práctica de la metodología en clase, mencionando algunas limitaciones a su adaptación a la realidad, aún en este capítulo se pondrá en destaque la importancia de generar empatía desde las primeras clases; por último, se trazará la experiencia en una clase ELE (la que fue objeto de estudio en la Práctica de la Enseñanza Supervisionada) de acuerdo con el Modelo Grow, la técnica más frecuente en coaching, describiendo el perfil de la reality y el plan de acción a llevar a la práctica a lo largo del curso según los objetivos planteados, culminando en la análisis de los resultados obtenidos y su evaluación con respecto a la efectiva prosecución de la metodología aplicada. Al final, se procederá a una reflexión generalizada sobre el coaching en la educación y sus supuestos beneficios, no solo en el espacio restricto del aula, sino en el espacio más alargado del Colegio, en una perspectiva de crear alumnos más motivados y responsables, involucrados en «aprender a aprender», «aprender a hacer», «aprender a vivir» y «aprender a ser» - aspectos fundamentales en la creación de una Escuela de futuro.
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25th International Cryogenic Engineering Conference and the International Cryogenic Materials Conference in 2014, ICEC 25–ICMC 2014
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Este estudio pretende valorar la competencia sociocultural, presentando un abanico de actividades para desarrollarla en clase con nuestros alumnos. Asimismo se mostrará cómo un profesor puede y debe ser un mediador en la transmisión y adquisición de contenidos socioculturales. Para ello, en el primer capítulo se da la definición del término cultura, analizando la importancia de su integración en las clases de lengua y presentando la evolución del estudio de contenidos socioculturales en la didáctica de idiomas. Se analizará igualmente la relevancia dada hoy en día a los contenidos socioculturales en los documentos oficiales, el Marco Común Europeo de Referencia, el Plan Curricular del Instituto Cervantes y el Programa de Español del Ministerio de Educación Portugués. A continuación, definimos el concepto de interculturalidad e incidimos en el papel del profesor en la eliminación de estereotipos, prejuicios y malentendidos, en el descubrimiento de uno mismo y en la tolerancia por los demás, resaltando también la importancia de la intraculturalidad en las clases de lengua materna y terminando el capítulo con algunos aspectos socioculturales españoles, indispensables para la formación de un alumno de español. En un segundo capítulo, se presenta el Instituto de Ciências Educativas – institución privada en la que se realizó la Práctica Supervisionada de Español - , y se procede igualmente a la caracterización de los grupos. Finalmente, se presentan algunas de las actividades más significativas para el tema de estudio y su respectiva reflexión.
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Equity research report
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Fundação para a Ciência e a Tecnologia (FCT), Fundação Millennium bcp, Imprensa Nacional-Casa da Moeda
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Equity research report