274 resultados para tecnología e ingeniería química
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In this work, a sodium montmorillonite (Na+-Mt) was modified with two molecules simultaneously, an organic dye, methylene blue (MB), and ethyl hexadecyl dimethyl ammonium (EHDDMA). The synthesised organo-montmorillonites (OMt) combining different proportions of the two molecules were thoroughly characterised and mixed with ethylene vinyl acetate copolymer (EVA) in order to check the ability of these OMt as pigments and reinforcing additives. The synthesised OMt combining both surfactants, MB and EHDDMA, present higher interlayer distances than those with only MB, which were employed in previous works as nanopigments. When these OMt were incorporated in the EVA matrix, the obtained clay polymer nanocomposites (CPN) showed a high exfoliation degree of the OMt in the polymer, in such a way that at 80% of the cationic exchange capacity (CEC) of the Mt exchanged with EHDDMA, most of the OMt was exfoliated. Moreover, all the obtained CPN showed an increase in the Young's Moduli compared to the EVA reference, and especially those containing higher amounts of MB. The thermal stability of the CPN also increases with the MB content, compared to other CPN including conventional surfactants. The hiding power and colouring power achieved in the CPN are higher even with a much lower load of MB when EHDDMA is exchanged in the Mt.
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In this study 11 commercial roll-your-own (RYO) tobacco brands sold in Spain and the reference tobacco 3R4F have been smoked and several components of the mainstream tobacco smoke have been analyzed. Cigarettes were prepared using commercial tubes, and were smoked under smoking conditions based on the ISO 3308. The gaseous and condensed fractions of the smoke from RYO brands and 3R4F have been analyzed and compared. RYO tobaccos, as opposed to 3R4F, present lower amounts of condensed products in the traps than in the filters. In general, RYO tobaccos also provide lower yields of most of the compounds detected in the gas fraction. The yield of CO is between 15.4 and 20.4 mg/cigarette. In most of the cases studied, RYO tobaccos deliver higher amounts of nicotine than the 3R4F tobacco. On average, the yield of the different chemical families of compounds appearing in the particulate matter retained in the cigarette filters tends to be around three times higher than those obtained from 3R4F, whereas similar values have been obtained in the particulate matter retained in the traps located after the filters. It can be concluded that RYO tobaccos are not less hazardous than the reference tobacco, which may be contrary to popular belief.
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In the present work, we provide a systematic analysis about all tine streams involved in the zone connecting two consecutive sections for the design of distillation columns with different thermal feed conditions, product extractions and heat additions or withdrawals. This analysis allows a better understanding of what happens on a feed or side draw (of mass or energy) stage, what compositions are or are not in equilibrium, and the impact on internal liquid and vapor flows.
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The thermal degradation of flexible polyurethane foam has been studied under different conditions by thermogravimetric analysis (TG), thermogravimetric analysis-infrared spectrometry (TG-IR) and thermogravimetric analysis-mass spectrometry (TG-MS). For the kinetic study, dynamic and dynamic+isothermal runs were performed at different heating rates (5, 10 and 20 °C min−1) in three different atmospheres (N2, N2:O2 4:1 and N2:O2 9:1). Two reaction models were obtained, one for the pyrolysis and another for the combustion degradation (N2:O2 4:1 and N2:O2 9:1), simultaneously correlating the experimental data from the dynamic and dynamic+isothermal runs at different heating rates. The pyrolytic model considered consisted of two consecutive reactions with activation energies of 142 and 217.5 kJ mol−1 and reaction orders of 0.805 and 1.246. Nevertheless, to simulate the experimental data from the combustion runs, three consecutive reactions were employed with activation energies of 237.9, 103.5 and 120.1 kJ mol−1, and reaction orders of 2.003, 0.778 and 1.025. From the characterization of the sample employing TG-IR and TG-MS, the results obtained showed that the FPUF, under an inert atmosphere, started the decomposition breaking the urethane bond to produce long chains of ethers which were degraded immediately in the next step. However, under an oxidative atmosphere, at the first step not only the urethane bonds were broken but also some ether polyols started their degradation which finished at the second step producing a char that was degraded at the last stage.
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In the present work, a very detailed study of the reforming of syngas produced in the decomposition of Posidonia oceanica is done. The effect of the presence of different amounts of dolomite is analyzed. Also pyrolysis is studied, in nitrogen atmosphere, and gasification in the presence of air, oxygen and different amounts of steam. A detailed discussion on formation and destruction of tars is done. Furthermore, the effect of the heating rate in the decomposition and the residence time of the evolved gases are discussed. Syngas with ratio H2/CO from 0.3 to ca. 3 can be obtained from this interesting material. Marine species (microalgae) are usually studied with the aim of cultivating them for gas or oil production, but in this paper we draw attention to the possibility of using a natural resource with a very small impact in the ecosystem.
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The economic design of a distillation column or distillation sequences is a challenging problem that has been addressed by superstructure approaches. However, these methods have not been widely used because they lead to mixed-integer nonlinear programs that are hard to solve, and require complex initialization procedures. In this article, we propose to address this challenging problem by substituting the distillation columns by Kriging-based surrogate models generated via state of the art distillation models. We study different columns with increasing difficulty, and show that it is possible to get accurate Kriging-based surrogate models. The optimization strategy ensures that convergence to a local optimum is guaranteed for numerical noise-free models. For distillation columns (slightly noisy systems), Karush–Kuhn–Tucker optimality conditions cannot be tested directly on the actual model, but still we can guarantee a local minimum in a trust region of the surrogate model that contains the actual local minimum.
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Polyvinyl chloride (PVC) is one of the plastics most extensively used due to its versatility. The demand of PVC resin in Europe during 2012 reached 5000 ktonnes1. PVC waste management is a big problem because of the high volume generated all over the world and its chlorine content. End-of-life PVC is mainly mixed with municipal solid waste (MSW) and one common disposal option for this is waste-to-energy incineration (WtE). The presence of plastics such as PVC in the fuel mix increases the heating value of the fuel. PVC has two times higher energy content than MSW ‒around 20 MJ/kg vs 10 MJ/kg, respectively. However, the high chlorine content in PVC resin, 57 wt.%, may be a source for the formation of hazardous chlorinated organic pollutants in thermal processes. Chlorine present in the feedstock of WtE plants plays an important role in the formation of (i) chlorine (Cl2) and (ii) hydrochloric gas (HCl), both of them responsible for corrosion, and (iii) chlorinated organic pollutants2. In this work, pyrolytic and oxidative thermal degradation of PVC resin were carried out in a laboratory scale reactor at 500 ºC in order to analyze the influence of the reaction atmosphere on the emissions evolved. Special emphasis was put on the analysis of chlorinated organic pollutants such as polychlorodibenzo-p-dioxins (PCDDs), polychlorodibenzofurans (PCDFs) and other related compounds like polychlorobenzenes (PCBzs), polychlorophenols (PCPhs) and polycyclic aromatic hydrocarbons (PAHs). Another objective of this work was to compare the results with those of a previous work3 in which emissions at different temperatures in both pyrolysis and combustion of another PVC resin had been studied; in that case, experiments for PCDD/Fs emissions had been performed only at 850 ºC.
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El profesorado de la red participó durante el curso 2013/14 en un proyecto para el seguimiento e indicadores de calidad de la titulación máster universitario en prevención de riesgos laborales. Este Máster comenzó a impartirse en la Escuela Politécnica Superior de la Universidad de Alicante en el curso 2012/13. En el curso 2015/16 al Máster en prevención de riesgos laborales le corresponde la renovación de su acreditación, en base a los resultados de la docencia de los cursos 2013/14 y 2014/15, por lo que los resultados del presente proyecto son de interés para la renovación de la acreditación de la titulación.
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Se presentan los resultados del proceso de evaluación de algunas asignaturas experimentales incluidas dentro de diferentes títulos, Grado en Biología, Grado en Ciencias del Mar, Grado en Químicas, Grado en Óptica y Optometría y Grado en Ingeniería Química, en las que el Departamento de Química Orgánica de la Universidad de Alicante está involucrado. Los resultados recogidos muestran como la evaluación continua y la realización de una prueba final influyen en la calificación final de la asignatura. Además, dentro de la evaluación continua se han diseñado diferentes actividades, considerando la realización de prácticas de laboratorio, la resolución de problemas y presentación de los mismos, así como la entrega de cuestionarios y ejercicios a través de plataformas virtuales. Se presenta el análisis de como cada una de estas actividades contribuye en el resultado final obtenido por los estudiantes, mostrando que las actividades de carácter práctico influyen en la calificación final de una manera más positiva.
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Resumen del póster presentado en PIC2015 – the 14th International Congress on Combustion By-Products and Their Health Effects, Umeå, Sweden, 14-17 June 2015.
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Resumen de la comunicación presentada en PIC2015 – the 14th International Congress on Combustion By-Products and Their Health Effects, Umeå, Sweden, 14-17 June 2015.
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Resumen del póster presentado en Symposium on Renewable Energy and Products from Biomass and Waste, CIUDEN (Cubillos de Sil, León, Spain), 12-13 May 2015
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Resumen del póster presentado en Symposium on Renewable Energy and Products from Biomass and Waste, CIUDEN (Cubillos de Sil, León, Spain), 12-13 May 2015
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El presente trabajo se ha desarrollado conjuntamente con alumnos de la asignatura obligatoria “Gestión Integrada y Seguridad Industrial” del Máster de Ingeniería Química y la asignatura optativa de cuarto curso “Gestión Integrada en la Industria Química” del grado de Ingeniería Química. Se ha diseñado una actividad práctica con el fin de aplicar los conceptos teóricos impartidos en estas asignaturas. Con el reto de cocinar un Mug Cake o “bizcocho en taza” se ha logrado poner en práctica varios de los contenidos teóricos de las asignaturas, especialmente el capítulo 7 de la norma ISO 9001:2008, “Realización del producto”; así como otros conceptos de liderazgo y mejora continua. Los alumnos se dividieron en dos equipos formados por el mismo número de miembros y en los que se mantenía el mismo número de alumnos del grado y del máster. Previamente a la realización del taller los alumnos elaboraron una serie de procedimientos, registros y listados de verificación. La experiencia ha resultado altamente fructífera puesto que los alumnos se han enfrentado al reto de aplicar contenidos teóricos a procesos reales, ha mejorado su motivación e interés por la materia y han desarrollado técnicas de trabajo en equipo y organización personal aumentando su productividad.
Resumo:
El Máster universitario en prevención de riesgos laborales comenzó a impartirse en la Escuela Politécnica Superior de la Universidad de Alicante en el curso 2012/13. En el curso 2015/16 se desarrollara la cuarta edición de esta titulación. El Real Decreto 1393/2007, de 29 de octubre, por el que se establece la ordenación de las enseñanzas universitarias oficiales, modificado por el Real Decreto 861/2010, de 2 de julio, señala en el artículo 27 que, una vez iniciada la implantación de las enseñanzas, la ANECA, o los órganos de evaluación que la ley de las comunidades autónomas determinen, llevarán a cabo el seguimiento del cumplimiento del proyecto contenido en el plan de estudios. Al Máster universitario en prevención de riesgos laborales le corresponde en el curso 2015/16 la renovación de su acreditación, en base a los resultados de la docencia de los cursos 2013/14 y 2014/15. Este proyecto se centra en la preparación de los datos necesarios para el informe de autoevaluación, que será necesario presentar para la evaluación externa de la renovación de la acreditación de la titulación.