274 resultados para tecnología e ingeniería química
Resumo:
An accurate and easy method for the extraction, cleanup, and HRGC-HRMS analysis of dioxin-like PCBs (DL-PCBs) in low-volume serum samples (1 mL) was developed. Serum samples were extracted several times using n-hexane and purified by acid washing. Recovery rates of labeled congeners ranged from 70 to 110 % and the limits of detection were below 1 pg/g on lipid basis. Although human studies are limited and contradictory, several studies have shown that DL-PCBs can have adverse effects on the male reproductive system. In this way, the present method was applied to 21 serum samples of male patients attending fertility clinics. The total levels obtained for the patients ranged from 6.90 to 84.1 pg WHO-TEQ/g lipid, with a mean value of 20.3 pg WHO-TEQ/g lipid. The predominant PCBs (the sum of PCB 118, 156, and 105) contributed 67 % to the mean concentration of total DL-PCBs in the samples analyzed.
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Two as-synthesized meso- and macro-porous siliceous materials (MPSMs), i.e., Al-MCM-41 and SBA-15, were mixed with tobacco to study their effect on tobacco smoke chemistry. A reference cigarette, 3R4F, and a commercial cigarette, Fortuna, containing different percentages of MPSM were smoked in a smoking machine, and the mainstream smoke was analyzed. SBA-15 showed the highest reductions of nicotine; close to 90% when it was added at 8 mass %. The superb behavior of these materials may be related to their high particulate matter filtering efficiency in combination with their catalytic activity. The selectivity of these materials with respect to nicotine was also analyzed. Al-MCM-41 presents higher selectivity for condensed compounds than for gases, whereas SBA-15 presents similar ratios for both fractions. The highest selectivity was obtained for the liquid fraction when smoking 3R4F cigarettes mixed with Al-MCM-41.
Resumo:
Diammonium hydrogen phosphate (DAP) is commonly used as a flavor ingredient of commercial cigarettes. In addition, among its other uses, it is employed to expand the tobacco volume, to manufacture reconstituted tobacco sheet, and to denicotinize tobacco. However, the use of DAP as a cigarette ingredient is a controversial issue. Some authors have stated that ammonium compounds added to tobacco increase smoke ammonia and “smoke pH”, resulting in more free nicotine available in the smoke. On the other hand, other researchers have reported that the larger ammonium content of a cigarette blend due to the presence of DAP was not reflected in increased smoke ammonia. In this work, the thermal behavior of DAP, tobacco and DAP-tobacco mixtures has been studied by TGA/FTIR. The chemical processes involved in the different pyrolysis steps of DAP have been suggested. Marked changes in the pyrolytic behavior of both, tobacco and DAP have been detected when analyzing the behavior of the mixtures. A displacement of the decomposition steps mainly related to the glycerol and lignin from tobacco toward lower temperatures has been observed, whereas that associated with cellulose is displaced toward higher temperature. Additionally, no peak corresponding to the phosphorous oxides decomposition has been detected in the curves relating to the DAP-tobacco mixtures. All these features are indicative of the strong interactions between DAP and tobacco. The FTIR spectra show no significant qualitative differences between the qualitative overall composition of the gases evolved from the pyrolysis of tobacco in the absence and in the presence of DAP. Nevertheless, depending on the temperature considered, the addition of DAP contributes to a decrease in the generation of hydrocarbons and an increase in the formation of CO, CO2 and oxygenated compounds in terms of amount generated per mass of pyrolysed tobacco.
Resumo:
Although hydrothermal carbonization of biomass components is known to be mainly governed by reaction temperature, consistent reports on the effect and statistical significance of process conditions on hydrochar properties are still lacking. The objective of this research was to determine the importance and significance of reaction temperature, retention time and solid load on the properties of hydrochar produced from an industrial lignocellulosic sludge residue. According to the results, reaction temperature and retention time had a statistically significant effect on hydrochar ash content, solid yield, carbon content, O/C-ratio, energy densification and energy yield as reactor solid load was statistically insignificant for all acquired models within the design range. Although statistically significant, the effect of retention time was 3–7 times lower than that of reaction temperature. Predicted dry ash-free solid yields of attained hydrochar decreased to approximately 40% due to the dissolution of biomass components at higher reaction temperatures, as respective oxygen contents were comparable to subbituminous coal. Significant increases in the carbon contents of hydrochar led to predicted energy densification ratios of 1–1.5 with respective energy yields of 60–100%. Estimated theoretical energy requirements of carbonization were dependent on the literature method used and mainly controlled by reaction temperature and reactor solid load. The attained results enable future prediction of hydrochar properties from this feedstock and help to understand the effect of process conditions on hydrothermal treatment of lignocellulosic biomass.
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Zero valent iron nanoparticles (nZVI) represent a promising agent for environmental remediation. Nevertheless, their application presents some limitations regarding their rapid oxidation and aggregation in the media. The aim of this study was to determine the effect that nZVI aging has in heavy metal remediation in water. Contaminants studied were Zn, Cd, Ni, Cu and Cr, which are typical elements found in ground and wastewater. Results show a high contaminant removal capacity by the nZVI in the first 2 h of reaction. Nevertheless, for longer reaction times, some of the metal ions that had already been adsorbed in the nZVI were delivered to the water. Cd and Ni show the maximum delivery percentages (65 and 27% respectively after 21 days of contact time). The starting delivery time was shortened when applying lower nZVI amounts. No re-dissolution of Cr was observed in any circumstance because it was the only element incorporated into the nanoparticles core, as TEM images showed. Contaminant release from nZVI is probably due to nanoparticles oxidation caused by aging, which produced a pH decrease and nZVI surface crystallization.
Resumo:
The thermal decomposition of a solid recovered fuel has been studied using thermogravimetry, in order to get information about the main steps in the decomposition of such material. The study comprises two different atmospheres: inert and oxidative. The kinetics of decomposition is determined at three different heating rates using the same kinetic constants and model for both atmospheres at all the heating rates simultaneously. A good correlation of the TG data is obtained using three nth-order parallel reactions.
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Las nuevas tecnologías en el proceso de enseñanzaaprendizaje, durante algunos años, han jugado un papel meramente espectador. Con la llegada de las aplicaciones Web 2.0 y el concepto e-Learning, las nuevas tecnologías pasan a tener un rol de canalizador de la enseñanza. Ante la llegada del Espacio Europeo de Educación Superior (EEES) la comunidad universitaria se enfrenta a un cambio en la filosofía de trabajo. En este trabajo, se presenta la aplicación de la suite orientada a la educación de Google (Google Apps) a la docencia en la titulación de Ingeniero en Sonido e Imagen impartida en la Escuela Politécnica Superior (EPS) de la Universidad de Alicante (UA ). El conjunto de herramientas web colaborativas se han aplicado en dos vertientes bien diferenciadas: en la docencia de la asignatura Proyectos e Infraestructuras de Telecomunicación II (PIT 2) de 6 Créditos ECTS obligatorios en 4º curso, y a la dirección del Proyecto Fin de Carrera (PFC). La incursión de las nuevas titulaciones de Grado en la UA ha favorecido la implantación de un Curso de adaptación al Grado en Ingeniería en Sonido e Imagen, orientado a los titulados en Ingeniería Técnica de Telecomunicación, especialidad en Sonido e Imagen, con el fin de continuar su formación. Este Curso de adaptación presenta una casuística que favorece el uso de nuevas técnicas docentes.
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El profesorado de la red docente realizó durante el curso 2009/10 un proyecto para la planificación de las asignaturas del primer curso del Grado en Ingeniería en Sonido e Imagen de la Escuela Politécnica Superior, y nos toca ahora la puesta a punto del primer curso del Grado. En el marco creado por los nuevos estudios dentro del EEES, el proyecto tiene como objetivo principal es el seguimiento, coordinación, evaluación, y mejora de la planificación realizada el curso anterior ya con las nuevas experiencias.
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Se han aplicado técnicas de análisis instrumental (FRX, DRX, ATR-IR, TG-ATD, SEM-EDX, MO) al estudio de fragmentos constructivos de época neolítica obtenidos de diferentes yacimientos de la Provincia de Alicante (España). La secuencia y el orden de aplicación de las técnicas se fija en función de las características y la cantidad disponible de cada muestra, estableciéndose con ello un protocolo de trabajo que se aplica siempre al resto de muestras, lo que nos permite comparar los resultados entre sí. El uso de dichas técnicas nos ha permitido la caracterización de los fragmentos constructivos, lo que nos ha llevado a conocer el grado de tecnología alcanzado por estas sociedades, sugiriéndonos que podíamos estar ante los inicios de la aplicación de la tecnología de la cal en esta zona de la Península Ibérica. En este trabajo se presenta una visión global de los resultados obtenidos hasta el momento.
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Libro de apuntes de Química (I) en Ing. de Obras Públicas.
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Temas de Química (II) para ITOP e ICCP.
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El profesorado de la red docente, que forma parte de la comisión académica del Máster, realizó durante el curso 2011/12 un proyecto para el estudio de los indicadores de calidad del Máster, en función de los indicadores de calidad de las Agencias acreditadoras y dependiendo de las tasas de éxito y eficacias durante el primer curso de implantación del Máster.
Resumo:
La red docente de la Comisión de plan de estudios de la titulación de Ingeniería Técnica de Telecomunicación, especialidad en Sonido e Imagen de la EPS ha realizado durante el curso 2007/08 un estudio de los objetivos y competencias del futuro título de grado, así como el análisis y diseño de la posible estructura en bloques y asignaturas obligatorias en la que se podría distribuir dicho título. El estudio toma como base los resultados obtenidos en redes de cursos anteriores (ver memoria de redes 2005/06 y 2006/07), las cuales estaban orientadas al diseño curricular dentro del marco de los créditos ECTS para la convergencia al Espacio Europeo de Educación Superior, y sobre todo, se basa en la experiencia de los propios participantes en trabajos o redes previas. El objetivo principal de este proyecto es el diseño curricular del futuro título de grado en Ingeniería de Telecomunicación en Sonido e Imagen, directamente relacionada con la actual Ingeniería Técnica de Telecomunicación, especialidad en Sonido e Imagen, que se imparte en la Universidad de Alicante. Para ello se han seguido las pautas generales establecidas por el Real Decreto de ordenación de Enseñanzas Universitarias Oficiales (BOE, 30 de octubre de 2007), así como otros documentos elaborados por el Colegio Oficial de Ingenieros Técnicos de Telecomunicación y la Comisión de Universidades de Ingeniería Técnica de Telecomunicación.