57 resultados para molt


Relevância:

10.00% 10.00%

Publicador:

Resumo:

The present work has two dimensions: analytical and environmental. On the one hand we proved that thermogravimetric analysis can be used to perform fast characterization of oil refinery sludge. To this end, thermogravimetric curves were deconvoluted by using autocatalytic kinetics to take into account acceleratory phases in a thermal degradation performed in oxygen-containing atmosphere or at high heating rates. Based on thermogravimetric results, oil refinery sludge was modeled in terms of various fractions (pseudo-components) which degrade as major oil cuts. On the other hand, as an alternative to landfill, we have seen that Soxhlet extraction allows recovery almost half of the weight of sludge as a mixture of hydrocarbons, similar to gas–oil, which burns without residue. This ensures both, waste inerting and significant reduction in sludge volume.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This study examined regular education teachers’ perceptions of inclusion in elementary and secondary schools in Spain and how these perceptions may differ depending on teaching experience, skills, and the availability of resources and supports. Stratified random sampling procedures were used to draw a representative sample of 336 general education teachers (68 kindergarten, 133 elementary, and 135 secondary teachers) from the province of Alicante. The results indicated the acceptance of the principles of inclusion, although teacher skills, time, material resources, and personal supports for inclusion were deemed insufficient. Kindergarten and elementary teachers showed more positive perceptions of inclusion than secondary education teachers, and so did teachers with more personal supports and material resources than those with less supports and resources. The results are discussed in terms of its implications for practice in order to promote more inclusive classrooms in Spain.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Combustion runs at 700 °C in a horizontal laboratory furnace were carried out on two different electric wires (PVC and halogen-free wire). Tests were performed in the presence and in the absence of the metal conductor of the wires. The analyses of the polycyclic aromatic hydrocarbons (PAHs), chlorobenzenes (CBzs), chlorophenols (CPhs), mono- to octa-chlorodibenzo-p-dioxin and dibenzofurans (PCDD/Fs), and dioxin-like PCBs are shown. Regarding semivolatile compounds, PAHs production decreases in the presence of metal, while a higher amount of chlorinated compounds are emitted. Respect to the PCDD/Fs, the PVC wire in the presence of metal presents the highest emission, with a much more emission of furans than dioxins. The maximum emission is with 2 or 3 chlorine atom PCDD/Fs. PCBs emission correlates with PCDD/F production and represents 3–4% of total toxicity, determined by using WHO2005 factors.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Thermal decomposition of printed circuits boards (PCB) is studied, using thermogravimetric analysis to compare the thermal behavior of PCB of mobile phones before and after the removal of the metallic fraction by acid washing. Several dynamic and dynamic + isothermal runs have been carried out at different heating rates (5, 10 and 20 K min−1), from room temperature to more than 1100 K. Also runs in the presence and in the absence of oxygen were performed (combustion and pyrolysis runs). Moreover, TG–MS experiments were performed (both in inert and oxidizing atmosphere) in order to better understand the thermal decomposition of these wastes and identify some compounds emitted during the controlled heating of these materials. Different reaction models are proposed, one for pyrolysis and one for combustion of the two kinds of wastes studied, which proved to simulate appropriately the experimental results at all the heating rates simultaneously.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pyrolysis and gasification of two different sludges coming from a Spanish refinery have been performed at different experimental conditions. A physico-chemical (PC) and a biological (BIO) sludge have been studied. Runs at different heating rates (approx. 4 and 10 K/s) and with different contact time between gases and decomposed sludge have been performed. In general, the ratio H2/CO is higher in pyrolytic runs. The highest ratio is obtained in the pyrolysis at low heating rate and parallel flow, using both sludges. The maximum emission of CO, i.e. the worst combustion conditions, is given in the runs where contact time is minimized and at high heating rates.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The aim of this study was to examine the extent to which teachers use inclusive practices to respond to students’ special needs in their classrooms and to determine whether grade level taught, training, and availability of resources and support affect the implementation of these practices. A research survey was designed for this purpose with the participation of a representative sample of 336 general education teachers (68 kindergarten, 133 elementary, and 135 secondary education teachers) in the province of Alicante, Spain. Findings reflected a moderate use of inclusive practices, with teachers more frequently implementing general adaptations rather than substantial ones. Statistically significant differences in use of inclusive practices were found as a function of the grade level taught, training received, and availability of material resources. Results are discussed in terms of their implication for teacher education reform and training programs.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Dins de la tasca de coordinació del primer curs del grau de telecomunicacions s'ha observat un grau molt elevat d'abandonament de la titulació. Aquest fet condiciona la tasca i metodologia docent. Amb la intenció d'incrementar la qualitat del nou grau i augmentar les taxes de eficàcia, hem buscat els motius que originen aquest alt grau d’abandonament dins la titulació i hem ideat possibles solucions que posen remei o pal·lien en certa mesura aquest problema. Per això es presenten estratègies i mecanismes per augmentar la qualitat de la docència, es comparen els resultats dels darrers cursos i s’analitzen els resultats de les estratègies posades en marxa. La tasca ha estat desenvolupada pels coordinadors de cada assignatura que conjuntament han analitzat com es va produir l'abandó durant l'avaluació continuada.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

El PAT en la Escuela Politécnica está abierto a todos aquellos tutores que deseen formar parte del plan y también a todos los alumnos, que, voluntariamente pueden marcar la opción de participar en el plan en la matrícula, y también a aquellos que, a pesar de no marcar la opción en la matrícula, finalmente han decidido seguir el plan de acción tutorial. Esta característica de participación e inscripción voluntaria permite que el trabajo se realice más satisfactoriamente tanto por parte de tutores como por parte de los alumnos, puesto que han decidido seguir el plan por ello mismos y no como una imposición. Con este trabajo nos proponemos presentar nuestras experiencias en el desarrollo de la tutorización de nuestros estudiantes así como la evolución en el desarrollo de la tutorización por pares.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Se propone la realización de un juego de rol con el objetivo de que los alumnos comprendan una asignatura a priori tediosa, Gestión Integrada en la Industria Química, de una forma práctica y amena. Este tipo de prueba facilita la evaluación de varias competencias a la vez, englobando tanto habilidades técnicas, como la comunicación oral y la puesta en escena. En este caso concreto los alumnos se han introducido en la situación de una auditoría de los distintos sistemas de gestión de la Universidad de Alicante, incluyendo calidad, medio ambiente y prevención de riesgos laborales. Los profesores han valorado las competencias adquiridas y los alumnos han realizado una encuesta para comprobar si ellos tienen la percepción de haberlas adquirido. Además se estudia su utilidad en un entorno laboral, en prácticas en empresa, ya que varios alumnos realizan las asignaturas de Prácticas Externas después de haber cursado la asignatura de Gestión Integrada en la Industria Química. El trabajo se completa con el estudio del posible interés de los juegos de rol en otras asignaturas de la titulación.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

En el curso 2013-14 se implantará el cuarto y último curso del Grado en Química. La experiencia adquirida durante la implementación de los tres primeros cursos ha puesto de manifiesto la conveniencia de realizar un proceso de coordinación entre los profesores de las diferentes asignaturas que garantice la consecución de las competencias previstas en la memoria del título. Por ello, se ha creado en la Facultad de Ciencias de la Universidad de Alicante una red de investigación en docencia universitaria que ha estado trabajando desde el inicio del presente curso académico en este tema. Dicha red está constituida por el Vicedecano de Ordenación Académica de la Facultad de Ciencias, la Coordinadora Académica de Química y los profesores coordinadores de todas las asignaturas del 4º curso del grado (excepto Prácticas Externas y Trabajo Fin de Grado). En esta comunicación se presentarán los resultados del trabajo de investigación realizado por estos profesores que ha permitido elaborar las guías docentes de las asignaturas, planificar y coordinar las actividades a realizar para que los alumnos adquieran las competencias transversales, realizar un cronograma de actividades de evaluación y otro de prácticas de laboratorio que asegure la distribución homogénea del trabajo del alumno durante el curso académico.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The purpose of this study was to examine the beliefs that teachers have about diversity and their level of sensitivity towards some topics related to it. Moreover, beliefs were compared according to teachers’ personal and professional views and teaching experience. The Personal and Professional Beliefs about Diversity Scales (Pohan and Aguilar, 1999) were administered to a sample of 233 teachers. Results showed highly positive beliefs towards diversity in all its dimensions (cultural, linguistic and social diversity, ability, gender, sexual orientation and religion), especially regarding its personal implications compared to the professional ones. Likewise, it was observed a significant relationship between years of teaching experience and professional beliefs about diversity, so teachers with no school experience showed a higher tolerance than those with teaching experience, mainly in aspects related to cultural, linguistic and social differences, ability and gender. The implications that these results have for educational practice and the need for the development of multicultural education courses that favour an effective teaching are discussed.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Aquest quadern ha sorgit amb l'objectiu de facilitar el material didàctic necessari per al seguiment de l'assignatura de Ciències socials i la seua didàctica, ubicada en el segon curs de Magisteri, especialitat Educació Primària. Els alumnes d'aquesta titulació tenen un pla d'estudi molt dens, i una simple observació posa de manifest la falta de temps per atendre la seua formació. Al mateix temps els avanços tant en la didàctica com en les ciències de referència, difosos en revistes especialitzades, llibres de congressos, o temàtics, ens aconsellen realitzar una selecció i presentar una síntesi, que servesca de punt de partida per tot l'alumnat que tinga una mínima inquietud. Per aquesta raó dins dels primers capítols i activitats d'aula es presenten les principals fonts d'informació com bibliografia, hemeroteca o direccions d'Internet. La Universitat d'Alacant, conscient que molts alumnes volen estudiar en valencià, ofereix al professors, a través del Secretariat de Promoció del Valencià, l'oportunitat d'elaborar materials docents en aquesta llengua. Per tant l'objectiu d'aquest quadern també és atendre la demanda social existent i proporcionar el material didàctic bàsic pel seguiment de l'assignatura de Ciències socials i la seua didàctica. Els continguts seleccionats per al quadern estan definits pel descriptor que marca la normativa i els principis de la ciència, que el docent a presentat als seus alumnes i que han sigut avaluats a classe al llarg de cinc cursos.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

On the basis of laboratory experiments with model mixtures (active carbon + CuBr2 at different loads), this work studies the formation of polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) by de novo synthesis. For the different samples, the temperature of the maximum carbon oxidation rate was determined by thermogravimetric analysis, and a kinetic model was proposed for the degradation of the materials in an oxidizing atmosphere (synthetic air). The effect of the addition of different amounts of CuBr2 was studied, finding that its presence accelerates the degradation of the carbonaceous structure in the presence of oxygen. The thermal degradation of the samples in air is satisfactorily described by a first-order single-reaction model. In addition, combustion runs of one of the mixtures (consisting of activated carbon + 50 wt % CuBr2, pyrolyzed at 700 °C) were performed in a quartz horizontal laboratory furnace. The analysis of the emissions and the solid residue proved the formation of brominated dioxins and furans at 300, 400, and 500 °C, with a maximum yield at 300 °C (91.7 ng/g of total PBDD/Fs) and a higher bromination degree with increasing temperature.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The constant increase in the production of electronic devices implies the need for an appropriate management of a growing number of waste electrical and electronic equipment. Thermal treatments represent an interesting alternative to recycle this kind of waste, but particular attention has to be paid to the potential emissions of toxic by-products. In this study, the emissions from thermal degradation of printed circuit boards (with and without metals) have been studied using a laboratory scale reactor, under oxidizing and inert atmosphere at 600 and 850 °C. Apart from carbon oxides, HBr was the main decomposition product, followed by high amounts of methane, ethylene, propylene, phenol and benzene. The maximum formation of PAHs was found in pyrolysis at 850 °C, naphthalene being the most abundant. High levels of 2-, 4-, 2,4-, 2,6- and 2,4,6-bromophenols were found, especially at 600 °C. Emissions of PCDD/Fs and dioxin-like PCBs were quite low and much lower than that of PBDD/Fs, due to the higher bromine content of the samples. Combustion at 600 °C was the run with the highest PBDD/F formation: the total content of eleven 2,3,7,8-substituted congeners (tetra- through heptaBDD/Fs) was 7240 and 3250 ng WHO2005-TEQ/kg sample, corresponding to the sample with and without metals, respectively.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Paper submitted to the 7th International Symposium on Feedstock Recycling of Polymeric Materials (7th ISFR 2013), New Delhi, India, 23-26 October 2013.