969 resultados para Environmental problems


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Pós-graduação em Educação Escolar - FCLAR

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Pós-graduação em Geografia - IGCE

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Abstract Ethanol is a biofuel that has unique capabilities to mitigate global climate change by reducing greenhouse gas emissions while simultaneously supporting rural economies and decreasing the United States’ dependence on foreign oil. Currently, the state of Nebraska depends on corn ethanol, which may be unsustainable. Cellulosic ethanol is a promising alternative but it is not without its problems, including high production costs and potential environmental damage. This thesis is an attempt to understand the benefits, downfalls, and processes of corn-based and cellulosic ethanol and the potential implications to Nebraska. This research should shed some light on the current obstacles and environmental problems involved with production, as well as evaluate the potential economic benefits to Nebraska, while pointing out issues that should be further researched before implementation.

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Pós-graduação em Educação Escolar - FCLAR

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Pós-graduação em Geografia - IGCE

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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One of the overall goals of industries is to use packages that do not cause environmental problems at disposal time, but that have the same properties as the conventional ones. The goal of this study is to synthesize edible films based on hydroxypropyl methylcellulose (HPMC) with guava puree and chitosan (CS) nanoparticles. This was divided into two stages, the first is the synthesis of chitosan nanoparticles and the second is the production of the films. For the nanoparticles, average size and zeta potential measurements were performed. The characterizations of mechanical and thermal properties, solubility and water vapor permeability tests were conducted in the films. It was observed that when the nanoparticles were added to HPMC and guava puree films, they improved their mechanical and thermal properties, as well as decreased the films solubility and permeability. The potential application of the films prepared would be in edible films with flavor and odor to extend the shelf life of products.

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[EN] Bioindicators have been used in urban and industrial areas to control the atmospheric pollution because it constitutes one of the most important environmental problems of human health. In this sense, mosses are able to reflect the chemical composition of surrounding atmosphere that together with the easy production techniques becomes mosses as one of the potential bioindicators in Europe. This study is part of the Mossclone project (FP-7) and quantifies the adsorption of heavy metals on 4 typical moss species in order to propose one of them to be used for environmental monitoring in the moss bag technique.

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[ES] Los efluentes ganaderos constituyen un beneficioso aporte de nutrientes para los cultivos, que es fundamental a la hora de garantizar la sostenibilidad de la gestión de las explotaciones ganaderas, pudiendo ocasionar graves problemas ambientales si se emplean mal. La intensificación agraria ha convertido los efluentes ganaderos de subproducto a residuo. Su tratamiento con materiales locales y tecnologías de baja intensidad es una solución de bajo coste financiero y energético. En el proyecto REAGUA se plantea la posibilidad de utilizar el “picón” (lapilli) como material para el tratamiento del estiércol líquido de rumiantes, para su posterior empleo en el riego enterrado de especies forrajeras y biocombustibles, actuando el suelo como medio de depuración avanzado. Para ello, se diseña un sistema en el que se aporte el efluente con un flujo subsuperficial vertical en un medio no saturado, que circule por tres fases (en serie). Para determinar las condiciones de manejo que optimicen el filtrado se caracterizó el comportamiento hidráulico del picón y su capacidad de eliminar sustancias. Utilizando tres columnas rellenas de picón y un efluente de rumiantes, las reducciones de la DQO, DBO5 y amonio, fósforo y SS superaron el 80, 90% y 95% respectivamente, obteniéndose valores asumibles para inyectarse al riego.

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The future hydrogen demand is expected to increase, both in existing industries (including upgrading of fossil fuels or ammonia production) and in new technologies, like fuel cells. Nowadays, hydrogen is obtained predominantly by steam reforming of methane, but it is well known that hydrocarbon based routes result in environmental problems and besides the market is dependent on the availability of this finite resource which is suffering of rapid depletion. Therefore, alternative processes using renewable sources like wind, solar energy and biomass, are now being considered for the production of hydrogen. One of those alternative methods is the so-called “steam-iron process” which consists in the reduction of a metal-oxide by hydrogen-containing feedstock, like ethanol for instance, and then the reduced material is reoxidized with water to produce “clean” hydrogen (water splitting). This kind of thermochemical cycles have been studied before but currently some important facts like the development of more active catalysts, the flexibility of the feedstock (including renewable bio-alcohols) and the fact that the purification of hydrogen could be avoided, have significantly increased the interest for this research topic. With the aim of increasing the understanding of the reactions that govern the steam-iron route to produce hydrogen, it is necessary to go into the molecular level. Spectroscopic methods are an important tool to extract information that could help in the development of more efficient materials and processes. In this research, ethanol was chosen as a reducing fuel and the main goal was to study its interaction with different catalysts having similar structure (spinels), to make a correlation with the composition and the mechanism of the anaerobic oxidation of the ethanol which is the first step of the steam-iron cycle. To accomplish this, diffuse reflectance spectroscopy (DRIFTS) was used to study the surface composition of the catalysts during the adsorption of ethanol and its transformation during the temperature program. Furthermore, mass spectrometry was used to monitor the desorbed products. The set of studied materials include Cu, Co and Ni ferrites which were also characterized by means of X-ray diffraction, surface area measurements, Raman spectroscopy, and temperature programmed reduction.

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At global level, the population is increasingly concentrating in the cities. In Europe, around 75% of the population lives in urban areas and, according to the European Environmental Agency (2010), urban population is foreseen to increase up to 80 % by 2020. At the same time, the quality of life in the cities is declining and urban pollution keeps increasing in terms of carbon dioxide (CO2) emissions, waste, noise, and lack of greenery. Many of European cities struggle to cope with social, economic and environmental problems resulting from pressures such as overcrowding or decline, social inequity, health problems related to food security and pollution. Nowadays local authorities try to solve these problems related to the environmental sustainability through various urban logistics measures, which directly and indirectly affect the urban food supply system, thus an integrated approach including freight transport and food provisioning policies issues is needed. This research centres on the urban food transport system and its impact on the city environmental sustainability. The main question that drives the research analysis is "How the urban food distribution system affects the ecological sustainability in modern cities?" The research analyses the city logistics project for food transport implemented in Parma, Italy, by the wholesale produce market. The case study investigates the renewed role of the wholesale market in the urban food supply chain as commercial and logistic operator, referring to the concept of food hub. Then, a preliminary analysis on the urban food transport for the city of Bologna is presented. The research aims at suggesting a methodological framework to estimate the urban food demand, the urban food supply and to assess the urban food transport performance, in order to identify external costs indicators that help policymakers in evaluating the environmental sustainability of different logistics measures

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„Abstract“ Pantring, Heinz Schulische Umwelterziehung und Umweltbewußtsein. Eine empirische Untersuchung zur Umwelterziehung und zum Umweltbewußtsein an Wiesbadener Schulen. Das Ziel der als Fallstudie konzipierten Untersuchung bestand darin, die Wirksamkeit schulischer Umwelterziehung nicht nur auf der Wissens- und Einstellungsdimension des Umweltbewußtseins, sondern vor allen Dingen auf die Dimension des Umwelthandelns im Sinne von „ökologischem Tun“ in Abhängigkeit von manifesten Persönlichkeitsmerkmalen wie Alter, Geschlecht und Dauer des Schulbesuchs zu überprüfen. Diese Überprüfung geschah durch das Angebot an alle Schüler und Lehrer, sich an einer konkreten Umweltaktion - Anlage eines Feuchtbiotops - zu beteiligen. An den Fragebogenerhebungen waren 1821 Schüler der 4., 8. und 12. Klassen aus 19 Wiesbadener Grund- und weiterführenden Schulen beteiligt. Parallel wurden bei den 550 Lehrerinnen und Lehrern, die an den entsprechenden Schulen unterrichteten, unter anderem Ausmaß und Qualität schulischer Umwelterziehung und umweltbezogener Fortbildung sowie Aspekte der Ökologisierung von Schule und Ansichten zum Umweltunterricht erfaßt. Wesentliche Ergebnisse waren: 1) Die zur Zeit praktizierte umweltorientierte Lehrerfortbildung erreicht nur einen geschlossenen Teilnehmerkreis. 2) Eine qualitative Verbesserung des Umweltunterrichtes ist eher auf Privatinitiative, als auf ein umfassendes institutionalisiertes umweltbezogenes Fortbildungsange-bot zurückzuführen. 3) Grundschüler zeigen ein ausgeprägteres Umweltbewußtsein als Schüler weiterführender Schulen. 4) Ein Großteil der in den Grundschulen durch eine intensive Schüler - Lehrer - Interaktion erreichte Motivation für Umweltprobleme und Umweltthemen geht beim Übergang von den Grundschulen zu den weiterführenden Schulen - insbesondere Gymnasien - verloren. Im Alter von 13 - 16 Jahren fallen die Schüler in ein „Motivationsloch“ für Umwelt-erziehung. 5) Schüler zeigen eine deutliche Diskrepanz zwischen verbalem umweltorientierten Engagement und dem faktisch praktizierten „Ökologischen Tun“. 6) Es gibt keinen signifikanten Zusammenhang zwischen der umweltbezogenen Handlungsbereitschaft von Schülern und der Qualität des Umweltunterrichtes. 7) Das bei Schülern allgemein entwickelte Umweltbewußtsein hängt eher mit ihrer Sozialisation in einer umweltbewußteren Zeit als mit den unmittelbaren Anstrengungen der Schule zusammen.

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Il siero di latte e la scotta sono effluenti provenienti rispettivamente dal processo di trasformazione del latte in formaggio e ricotta. Il siero di latte contiene minerali, lipidi, lattosio e proteine; la scotta contiene principalmente lattosio. Il siero può essere riutilizzato in diversi modi, come l'estrazione di proteine o per l’alimentazione animale, mentre la scotta è considerata solamente un rifiuto. Inoltre, a causa degli ingenti volumi di siero prodotti nel mondo, vengono a crearsi seri problemi ambientali e di smaltimento. Destinazioni alternative di questi effluenti, come le trasformazioni biotecnologiche, possono essere un modo per raggiungere il duplice obiettivo di migliorare il valore aggiunto dei processi agroindustriali e di ridurre il loro impatto ambientale. In questo lavoro sono state studiate le condizioni migliori per produrre bioetanolo dal lattosio del siero e della scotta. Kluyveromyces marxianus è stato scelto come lievito lattosio-fermentante. Sono state effettuate fermentazioni su scala di laboratorio aerobiche e anaerobiche in batch, fermentazioni semicontinue in fase dispersa e con cellule immobilizzate in alginato di calcio,. Diverse temperature sono state testate per migliorare la produzione di etanolo. Le migliori prestazioni, per entrambe le matrici, sono state raggiunte a basse temperature (28°C). Anche le alte temperature sono compatibili con buone rese di etanolo nelle fermentazioni con siero. Ottimi risultati si sono ottenuti anche con la scotta a 37°C e a 28°C. Le fermentazioni semicontinue in fase dispersa danno le migliori produzioni di etanolo, in particolare con la scotta. Invece, l'uso di cellule di lievito intrappolate in alginato di calcio non ha migliorato i risultati di processo. In conclusione, entrambi gli effluenti possono essere considerati adatti per la produzione di etanolo. Le buone rese ottenute dalla scotta permettono di trasformare questo rifiuto in una risorsa.