Perspectivas da governança e segurança climática global

Elabora um marco teórico-conceitual, destacando a importância do conceito de segurança climática global e sua relação com a governança e governabilidade. Descreve o perfil dos países emissores de gases de efeito estufa (GEE). Identifica as oportunidades técnico-econômicas para a transição para uma economia de baixo carbono que mitigue a mudança climática. Analisa três cenários prospectivos da evolução do sistema internacional, tendo como variável principal o grau de cooperação atingido.

O papel da energia nas ações de mitigação

Descreve as alternativas energéticas que se colocam para mitigar boa parte das emissões de gases de efeito estufa (GEE) do planeta. Enfatiza o potencial para o uso mais eficiente da energia em todos os setores da economia e nas oportunidade de substituição de combustíveis fósseis por combustíveis renováveis. Ressalta a importância de mudança de hábitos de consumo para reduzir as emissões de GEE a níveis considerados seguros, de maneira a se estabilizarem as concentrações de gases na atmosfera em níveis suficientemente baixos.

Aspectos geopolíticos das mudanças climáticas

Descreve e analisa aspectos do debate sobre as soluções a serem desenvolvidas mundialmente para controle das emissões de gases de efeito estufa (GEE), considerando "...a entrada da Natureza no jogo político global..." após a assinatura do Protocolo de Kyoto (1997). Aborda os seguintes tópicos : controle do desmatamento e criação de fontes alternativas de energia.

Ações de mitigação das emissões no Brasil

Sintetiza os fatos que levaram a adoção da Convenção-Quadro das Nações Unidas sobre Mudança do Clima. Descreve e analisa as iniciativas do Brasil no sentido de colaborar com a proteção climática e com a redução da emissão de gases poluentes. Destaca os seguintes pontos: desenvolvimento de matriz energética "limpa" (álcool e biodiesel); combate ao desperdício de energia elétrica; programa de redução de emissões veiculares; redução de incêndios florestais e do desmatamento; projetos ligados ao Mecanismo de Desenvolvimento Limpo.

Coflow jets with large velocity difference - a new aerodynamic principle of flame stabilization and combustion intensification

A new aerodynamic principle of flame stabilization and combustion intensification, the coflow jets with large velocity difference, is described. One or more small high-velocity jets of air or steam, injected off the axis and in the same direction as the low-velocity main fuel-air flow into the combustor, create a large recirculation zone of high turbulence intensity in which the combustibles and high temperature gases are effectively mixed, so that stable and intensive combustion can be maintained even for fuels with poor ignition. A pulverized coal combustor based on the principle mentioned above is shown to be characteristic of excellent combustoom and a simple structure. A number of precombustors of this type are in operation at some power stations and industrial boilers of China. Using such precombustor, successtul startups and part-load operation of the boilers have become available under conditions of unpreheated air and low-grade coal with volatiles as low as 15% and ash content as high as 30%. This principle shows good promise as an attractive new technology of combustion.

Non-linear theory of a positive-column in a magnetic-field

A nonlinear theory of an intermediate pressure discharge column in a magnetic field is presented. Motion of the neutral gas is considered. The continuity and momentum transfer equations for charged particles and neutral particles are solved by numerical methods. The main result obtained is that the rotating velocities of ionic gas and neutral gas are approximately equal. Bohm's criterion and potential inversion in the presence of neutral gas motion are also discussed.

可燃气体中激波聚焦的点火特性

数值模拟了二维平面激波从抛物面上反射在可燃气体中聚焦的过程，研究了形成爆轰波的点火特性,对理想化学当量比氢气／空气混合气体，在初始压强20kPa的条件下，马赫数2．6-2．8的激波聚焦能产生两个点火区：第1个点火区是反射激波会聚引起的，第2个点火区是由入射激波在抛物面上发生马赫反射引起的．这种条件下流场中会出现爆燃转爆轰，起爆点分别分布在管道壁面、抛物反射面和第2点火区附近．起爆机理分别为激波管道壁面反射、点火诱导激波的抛物面反射和点火诱导的激波与第2点火区产生的爆燃波的相互作用,不同的点火和起爆过程导致了不同的流场波系结构，同时影响了爆轰波传播的波动力学过程．

Chemical recycling of municipal packaging waste by pyrolysis

[EN]The present doctoral thesis centers on studying pyrolysis as a chemical recycling technique for rejected packaging waste fractions coming from separation and sorting plants. The pyrolysis experiments have been carried out in a lab-scale installation equipped with a 3.5 L semi-batch reactor and a condensation and collection system for the liquids and gases generated. In the present thesis, an experimental study on the conventional pyrolysis process applied to the aforementioned waste fractions has been conducted, as well as the study of non-conventional or advanced pyrolysis processes such as catalytic and stepwise pyrolysis. The study of the operating parameters has been carried out using a mixed plastics simulated sample, the composition of which is similar to that found in real fractions, and subsequently the optimized process has been applied to real packaging waste. An exhaustive characterization of the solids, liquids and gases obtained in the process has been made after each experiment and their potential uses have been established. Finally, an empirical model that will predict the pyrolysis yields (% organic liquid, % aqueous liquid, % gases, % char, % inorganic solid) as a function of the composition of the initial sample has been developed. As a result of the experimental work done, the requirements have been established for an industrial packaging waste pyrolysis plant that aims to be sufficiently versatile as to generate useful products regardless of the nature of the raw material.

¿Son fiables los productos que encontramos en los supermercados?

Duración (en horas): De 21 a 30 horas. Destinatario: Estudiante

Ingurumena

Capítulo 16

Distribution of Temperature in GlidArc Discharge Plasma

The GlidArc discharge is one of the main generation methods of non-equilibrium plasma near atmospheric pressures. In general, Gliding Arc discharge is driven by gas flow [1] in axial direction or by magnetic field in circumferential direction. [2] In this paper, a GlidArc discharge driven by rotating-gas-flow in circumferential direction is presented. The principle of the plasma generator is analyzed. The distribution of the temperature in axial direction is measured by a digital thermometer for three different gases. The experimental set-up of the GlidArc plasma is shown in Fig.1. It consists of a center electrode, an outside electrode, a power supply and a gas supply. The shortest distance between the electrodes is 2-3 mm. When a power supply with 10000 volts is attached to the electrodes, the arc will be ignited at the shortest distance. The small plasma column is rotated by the rotating gas flow in circumferential direction and then the rotating arc is driven towards the exit of the setup by the gas flow.

Separación de células cultivables y no cultivables mediante gradiente de densidad

Poster presentado al XX Congreso Nacional de Microbiología celebrado en Cáceres los días 19 -22 septiembre de 2005

Application of a new pelletised organic bed for tex biodegradation in conventional biofilters

La problemática de las emisiones de gases contaminados generadas por las actividades humanas ha obligado al desarrollo de distintas tecnologías de tratamiento cuyo objetivo es minimizar el efecto de las mismas sobre el medio ambiente.La biofiltración es una de estas tecnologías de bajo coste que además es respetuosa con el entorno. Básicamente consiste en hacer pasar un gas contaminado a través de un medio poroso donde anida la biomasa que lleva a cabo la degradación de los contaminantes, generando productos no nocivos. El presente estudio se ha centrado en aportar soluciones a una de las principales limitaciones que presentan estos sistemas biológicos: el excesivo tiempo empleado por la biomasa para adaptarse a los contaminantes y degradarlos eficazmente.Se ha desarrollado una sistemática de aclimatación que ha permitido acortar el tiempo de adaptación de la biomasa específica para la eliminación de compuestos orgánicos volátiles (COVs). Estos compuestos, más específicamente los TEX (tolueno, p-xileno y etilbenceno), son uno de los grupos de contaminantes más habituales a nivel industrial, e incluso en ambientes interiores. La optimización de los parámetros de operación que afectan a esta tecnología (el nivel de humedad del soporte, temperatura, la interacción de varios contaminantes presentes en la misma corriente gaseosa, entre otros), ha llevado a la consecución de eficacias de depuración muy elevadas en el biotratamiento en continuo de corrientes gaseosas contaminadas.

Global Climate Change Impacts in the United States: a state of knowledge report from the U.S. Global Change Research Program

Executive Summary: Observations show that warming of the climate is unequivocal. The global warming observed over the past 50 years is due primarily to human-induced emissions of heat-trapping gases. These emissions come mainly from the burning of fossil fuels (coal, oil, and gas), with important contributions from the clearing of forests, agricultural practices, and other activities. Warming over this century is projected to be considerably greater than over the last century. The global average temperature since 1900 has risen by about 1.5ºF. By 2100, it is projected to rise another 2 to 11.5ºF. The U.S. average temperature has risen by a comparable amount and is very likely to rise more than the global average over this century, with some variation from place to place. Several factors will determine future temperature increases. Increases at the lower end of this range are more likely if global heat-trapping gas emissions are cut substantially. If emissions continue to rise at or near current rates, temperature increases are more likely to be near the upper end of the range. Volcanic eruptions or other natural variations could temporarily counteract some of the human-induced warming, slowing the rise in global temperature, but these effects would only last a few years. Reducing emissions of carbon dioxide would lessen warming over this century and beyond. Sizable early cuts in emissions would significantly reduce the pace and the overall amount of climate change. Earlier cuts in emissions would have a greater effect in reducing climate change than comparable reductions made later. In addition, reducing emissions of some shorter-lived heat-trapping gases, such as methane, and some types of particles, such as soot, would begin to reduce warming within weeks to decades. Climate-related changes have already been observed globally and in the United States. These include increases in air and water temperatures, reduced frost days, increased frequency and intensity of heavy downpours, a rise in sea level, and reduced snow cover, glaciers, permafrost, and sea ice. A longer ice-free period on lakes and rivers, lengthening of the growing season, and increased water vapor in the atmosphere have also been observed. Over the past 30 years, temperatures have risen faster in winter than in any other season, with average winter temperatures in the Midwest and northern Great Plains increasing more than 7ºF. Some of the changes have been faster than previous assessments had suggested. These climate-related changes are expected to continue while new ones develop. Likely future changes for the United States and surrounding coastal waters include more intense hurricanes with related increases in wind, rain, and storm surges (but not necessarily an increase in the number of these storms that make landfall), as well as drier conditions in the Southwest and Caribbean. These changes will affect human health, water supply, agriculture, coastal areas, and many other aspects of society and the natural environment. This report synthesizes information from a wide variety of scientific assessments (see page 7) and recently published research to summarize what is known about the observed and projected consequences of climate change on the United States. It combines analysis of impacts on various sectors such as energy, water, and transportation at the national level with an assessment of key impacts on specific regions of the United States. For example, sea-level rise will increase risks of erosion, storm surge damage, and flooding for coastal communities, especially in the Southeast and parts of Alaska. Reduced snowpack and earlier snow melt will alter the timing and amount of water supplies, posing significant challenges for water resource management in the West. (PDF contains 196 pages)

Mezclas y nanocompuestos de policaprolactona y resina fenoxi: caracterización, morfología y propiedades de transporte

La Tesis recoge un estudio experimental sobre mezclas y nanocompuestos de dos polímeros comerciales, ambos con peculiares capacidades a la hora de disgregar arcillas a nivel nanoscópico y de mezclarse con otros polímeros, lo que les hace particularmente atractivos a la hora de preparar masterbatches con altos contenidos en arcillas. Se han estudiado, entre otros efectos, el papel que las arcillas juegan en los fenómenos de cristalización de la policaprolactona y, sobre todo, en las propiedades de transporte de gases y vapores a través de los nanocompuestos obtenidos con las arcillas y los polímeros objeto de la Tesis. Con idénticos puntos de vista se han analizado mezclas binarias de ambos polímeros, incluyendo un estudio tentativo de uno de sus posibles nanocompuestos. Finalmente, se ha realizado un estudio de mezclas de policaprolactona con un polímero conductor, el polipirrol. En este caso, la cristalización del primero induce, con pequeñas cantidades del segundo, una red en éste que asegura una conductividad estimable y una mejora en las propiedades de transporte al dióxido de carbono.