946 resultados para Environmental impacts.
Resumo:
The paper reviews relevant literature studying the environmental impacts of food supply chain from production to each stage throughout the supply chain. With limited data and information, to better understand these impacts, a concrete example of the tea supply chain in China is provided. The tea supply chain is analyzed from the environmental prospective, with potential pollutants being identified at each stage of the supply chain. As an example of the food supply chain in a developing country, some unique features of the developing economies are taken into consideration when concluding the implications.
Resumo:
RESUMEN La dispersión del amoniaco (NH3) emitido por fuentes agrícolas en medias distancias, y su posterior deposición en el suelo y la vegetación, pueden llevar a la degradación de ecosistemas vulnerables y a la acidificación de los suelos. La deposición de NH3 suele ser mayor junto a la fuente emisora, por lo que los impactos negativos de dichas emisiones son generalmente mayores en esas zonas. Bajo la legislación comunitaria, varios estados miembros emplean modelos de dispersión inversa para estimar los impactos de las emisiones en las proximidades de las zonas naturales de especial conservación. Una revisión reciente de métodos para evaluar impactos de NH3 en distancias medias recomendaba la comparación de diferentes modelos para identificar diferencias importantes entre los métodos empleados por los distintos países de la UE. En base a esta recomendación, esta tesis doctoral compara y evalúa las predicciones de las concentraciones atmosféricas de NH3 de varios modelos bajo condiciones, tanto reales como hipotéticas, que plantean un potencial impacto sobre ecosistemas (incluidos aquellos bajo condiciones de clima Mediterráneo). En este sentido, se procedió además a la comparación y evaluación de varias técnicas de modelización inversa para inferir emisiones de NH3. Finalmente, se ha desarrollado un modelo matemático simple para calcular las concentraciones de NH3 y la velocidad de deposición de NH3 en ecosistemas vulnerables cercanos a una fuente emisora. La comparativa de modelos supuso la evaluación de cuatro modelos de dispersión (ADMS 4.1; AERMOD v07026; OPS-st v3.0.3 y LADD v2010) en un amplio rango de casos hipotéticos (dispersión de NH3 procedente de distintos tipos de fuentes agrícolas de emisión). La menor diferencia entre las concentraciones medias estimadas por los distintos modelos se obtuvo para escenarios simples. La convergencia entre las predicciones de los modelos fue mínima para el escenario relativo a la dispersión de NH3 procedente de un establo ventilado mecánicamente. En este caso, el modelo ADMS predijo concentraciones significativamente menores que los otros modelos. Una explicación de estas diferencias podríamos encontrarla en la interacción de diferentes “penachos” y “capas límite” durante el proceso de parametrización. Los cuatro modelos de dispersión fueron empleados para dos casos reales de dispersión de NH3: una granja de cerdos en Falster (Dinamarca) y otra en Carolina del Norte (EEUU). Las concentraciones medias anuales estimadas por los modelos fueron similares para el caso americano (emisión de granjas ventiladas de forma natural y balsa de purines). La comparación de las predicciones de los modelos con concentraciones medias anuales medidas in situ, así como la aplicación de los criterios establecidos para la aceptación estadística de los modelos, permitió concluir que los cuatro modelos se comportaron aceptablemente para este escenario. No ocurrió lo mismo en el caso danés (nave ventilada mecánicamente), en donde el modelo LADD no dio buenos resultados debido a la ausencia de procesos de “sobreelevacion de penacho” (plume-rise). Los modelos de dispersión dan a menudo pobres resultados en condiciones de baja velocidad de viento debido a que la teoría de dispersión en la que se basan no es aplicable en estas condiciones. En situaciones de frecuente descenso en la velocidad del viento, la actual guía de modelización propone usar un modelo que sea eficaz bajo dichas condiciones, máxime cuando se realice una valoración que tenga como objeto establecer una política de regularización. Esto puede no ser siempre posible debido a datos meteorológicos insuficientes, en cuyo caso la única opción sería utilizar un modelo más común, como la versión avanzada de los modelos Gausianos ADMS o AERMOD. Con el objetivo de evaluar la idoneidad de estos modelos para condiciones de bajas velocidades de viento, ambos modelos fueron utilizados en un caso con condiciones Mediterráneas. Lo que supone sucesivos periodos de baja velocidad del viento. El estudio se centró en la dispersión de NH3 procedente de una granja de cerdos en Segovia (España central). Para ello la concentración de NH3 media mensual fue medida en 21 localizaciones en torno a la granja. Se realizaron también medidas de concentración de alta resolución en una única localización durante una campaña de una semana. En este caso, se evaluaron dos estrategias para mejorar la respuesta del modelo ante bajas velocidades del viento. La primera se basó en “no zero wind” (NZW), que sustituyó periodos de calma con el mínimo límite de velocidad del viento y “accumulated calm emissions” (ACE), que forzaban al modelo a calcular las emisiones totales en un periodo de calma y la siguiente hora de no-calma. Debido a las importantes incertidumbres en los datos de entrada del modelo (inputs) (tasa de emisión de NH3, velocidad de salida de la fuente, parámetros de la capa límite, etc.), se utilizó el mismo caso para evaluar la incertidumbre en la predicción del modelo y valorar como dicha incertidumbre puede ser considerada en evaluaciones del modelo. Un modelo dinámico de emisión, modificado para el caso de clima Mediterráneo, fue empleado para estimar la variabilidad temporal en las emisiones de NH3. Así mismo, se realizó una comparativa utilizando las emisiones dinámicas y la tasa constante de emisión. La incertidumbre predicha asociada a la incertidumbre de los inputs fue de 67-98% del valor medio para el modelo ADMS y entre 53-83% del valor medio para AERMOD. La mayoría de esta incertidumbre se debió a la incertidumbre del ratio de emisión en la fuente (50%), seguida por la de las condiciones meteorológicas (10-20%) y aquella asociada a las velocidades de salida (5-10%). El modelo AERMOD predijo mayores concentraciones que ADMS y existieron más simulaciones que alcanzaron los criterios de aceptabilidad cuando se compararon las predicciones con las concentraciones medias anuales medidas. Sin embargo, las predicciones del modelo ADMS se correlacionaron espacialmente mejor con las mediciones. El uso de valores dinámicos de emisión estimados mejoró el comportamiento de ADMS, haciendo empeorar el de AERMOD. La aplicación de estrategias destinadas a mejorar el comportamiento de este último tuvo efectos contradictorios similares. Con el objeto de comparar distintas técnicas de modelización inversa, varios modelos (ADMS, LADD y WindTrax) fueron empleados para un caso no agrícola, una colonia de pingüinos en la Antártida. Este caso fue empleado para el estudio debido a que suponía la oportunidad de obtener el primer factor de emisión experimental para una colonia de pingüinos antárticos. Además las condiciones eran propicias desde el punto de vista de la casi total ausencia de concentraciones ambiente (background). Tras el trabajo de modelización existió una concordancia suficiente entre las estimaciones obtenidas por los tres modelos. De este modo se pudo definir un factor de emisión de para la colonia de 1.23 g NH3 por pareja criadora por día (con un rango de incertidumbre de 0.8-2.54 g NH3 por pareja criadora por día). Posteriores aplicaciones de técnicas de modelización inversa para casos agrícolas mostraron también un buen compromiso estadístico entre las emisiones estimadas por los distintos modelos. Con todo ello, es posible concluir que la modelización inversa es una técnica robusta para estimar tasas de emisión de NH3. Modelos de selección (screening) permiten obtener una rápida y aproximada estimación de los impactos medioambientales, siendo una herramienta útil para evaluaciones de impactos en tanto que permite eliminar casos que presentan un riesgo potencial de daño bajo. De esta forma, lo recursos del modelo pueden Resumen (Castellano) destinarse a casos en donde la posibilidad de daño es mayor. El modelo de Cálculo Simple de los Límites de Impacto de Amoniaco (SCAIL) se desarrolló para obtener una estimación de la concentración media de NH3 y de la tasa de deposición seca asociadas a una fuente agrícola. Está técnica de selección, basada en el modelo LADD, fue evaluada y calibrada con diferentes bases de datos y, finalmente, validada utilizando medidas independientes de concentraciones realizadas cerca de las fuentes. En general SCAIL dio buenos resultados de acuerdo a los criterios estadísticos establecidos. Este trabajo ha permitido definir situaciones en las que las concentraciones predichas por modelos de dispersión son similares, frente a otras en las que las predicciones difieren notablemente entre modelos. Algunos modelos nos están diseñados para simular determinados escenarios en tanto que no incluyen procesos relevantes o están más allá de los límites de su aplicabilidad. Un ejemplo es el modelo LADD que no es aplicable en fuentes con velocidad de salida significativa debido a que no incluye una parametrización de sobreelevacion del penacho. La evaluación de un esquema simple combinando la sobreelevacion del penacho y una turbulencia aumentada en la fuente mejoró el comportamiento del modelo. Sin embargo más pruebas son necesarias para avanzar en este sentido. Incluso modelos que son aplicables y que incluyen los procesos relevantes no siempre dan similares predicciones. Siendo las razones de esto aún desconocidas. Por ejemplo, AERMOD predice mayores concentraciones que ADMS para dispersión de NH3 procedente de naves de ganado ventiladas mecánicamente. Existe evidencia que sugiere que el modelo ADMS infraestima concentraciones en estas situaciones debido a un elevado límite de velocidad de viento. Por el contrario, existen evidencias de que AERMOD sobreestima concentraciones debido a sobreestimaciones a bajas Resumen (Castellano) velocidades de viento. Sin embrago, una modificación simple del pre-procesador meteorológico parece mejorar notablemente el comportamiento del modelo. Es de gran importancia que estas diferencias entre las predicciones de los modelos sean consideradas en los procesos de evaluación regulada por los organismos competentes. Esto puede ser realizado mediante la aplicación del modelo más útil para cada caso o, mejor aún, mediante modelos múltiples o híbridos. ABSTRACT Short-range atmospheric dispersion of ammonia (NH3) emitted by agricultural sources and its subsequent deposition to soil and vegetation can lead to the degradation of sensitive ecosystems and acidification of the soil. Atmospheric concentrations and dry deposition rates of NH3 are generally highest near the emission source and so environmental impacts to sensitive ecosystems are often largest at these locations. Under European legislation, several member states use short-range atmospheric dispersion models to estimate the impact of ammonia emissions on nearby designated nature conservation sites. A recent review of assessment methods for short-range impacts of NH3 recommended an intercomparison of the different models to identify whether there are notable differences to the assessment approaches used in different European countries. Based on this recommendation, this thesis compares and evaluates the atmospheric concentration predictions of several models used in these impact assessments for various real and hypothetical scenarios, including Mediterranean meteorological conditions. In addition, various inverse dispersion modelling techniques for the estimation of NH3 emissions rates are also compared and evaluated and a simple screening model to calculate the NH3 concentration and dry deposition rate at a sensitive ecosystem located close to an NH3 source was developed. The model intercomparison evaluated four atmospheric dispersion models (ADMS 4.1; AERMOD v07026; OPS-st v3.0.3 and LADD v2010) for a range of hypothetical case studies representing the atmospheric dispersion from several agricultural NH3 source types. The best agreement between the mean annual concentration predictions of the models was found for simple scenarios with area and volume sources. The agreement between the predictions of the models was worst for the scenario representing the dispersion from a mechanically ventilated livestock house, for which ADMS predicted significantly smaller concentrations than the other models. The reason for these differences appears to be due to the interaction of different plume-rise and boundary layer parameterisations. All four dispersion models were applied to two real case studies of dispersion of NH3 from pig farms in Falster (Denmark) and North Carolina (USA). The mean annual concentration predictions of the models were similar for the USA case study (emissions from naturally ventilated pig houses and a slurry lagoon). The comparison of model predictions with mean annual measured concentrations and the application of established statistical model acceptability criteria concluded that all four models performed acceptably for this case study. This was not the case for the Danish case study (mechanically ventilated pig house) for which the LADD model did not perform acceptably due to the lack of plume-rise processes in the model. Regulatory dispersion models often perform poorly in low wind speed conditions due to the model dispersion theory being inapplicable at low wind speeds. For situations with frequent low wind speed periods, current modelling guidance for regulatory assessments is to use a model that can handle these conditions in an acceptable way. This may not always be possible due to insufficient meteorological data and so the only option may be to carry out the assessment using a more common regulatory model, such as the advanced Gaussian models ADMS or AERMOD. In order to assess the suitability of these models for low wind conditions, they were applied to a Mediterranean case study that included many periods of low wind speed. The case study was the dispersion of NH3 emitted by a pig farm in Segovia, Central Spain, for which mean monthly atmospheric NH3 concentration measurements were made at 21 locations surrounding the farm as well as high-temporal-resolution concentration measurements at one location during a one-week campaign. Two strategies to improve the model performance for low wind speed conditions were tested. These were ‘no zero wind’ (NZW), which replaced calm periods with the minimum threshold wind speed of the model and ‘accumulated calm emissions’ (ACE), which forced the model to emit the total emissions during a calm period during the first subsequent non-calm hour. Due to large uncertainties in the model input data (NH3 emission rates, source exit velocities, boundary layer parameters), the case study was also used to assess model prediction uncertainty and assess how this uncertainty can be taken into account in model evaluations. A dynamic emission model modified for the Mediterranean climate was used to estimate the temporal variability in NH3 emission rates and a comparison was made between the simulations using the dynamic emissions and a constant emission rate. Prediction uncertainty due to model input uncertainty was 67-98% of the mean value for ADMS and between 53-83% of the mean value for AERMOD. Most of this uncertainty was due to source emission rate uncertainty (~50%), followed by uncertainty in the meteorological conditions (~10-20%) and uncertainty in exit velocities (~5-10%). AERMOD predicted higher concentrations than ADMS and more of the simulations met the model acceptability criteria when compared with the annual mean measured concentrations. However, the ADMS predictions were better correlated spatially with the measurements. The use of dynamic emission estimates improved the performance of ADMS but worsened the performance of AERMOD and the application of strategies to improved model performance had similar contradictory effects. In order to compare different inverse modelling techniques, several models (ADMS, LADD and WindTrax) were applied to a non-agricultural case study of a penguin colony in Antarctica. This case study was used since it gave the opportunity to provide the first experimentally-derived emission factor for an Antarctic penguin colony and also had the advantage of negligible background concentrations. There was sufficient agreement between the emission estimates obtained from the three models to define an emission factor for the penguin colony (1.23 g NH3 per breeding pair per day with an uncertainty range of 0.8-2.54 g NH3 per breeding pair per day). This emission estimate compared favourably to the value obtained using a simple micrometeorological technique (aerodynamic gradient) of 0.98 g ammonia per breeding pair per day (95% confidence interval: 0.2-2.4 g ammonia per breeding pair per day). Further application of the inverse modelling techniques for a range of agricultural case studies also demonstrated good agreement between the emission estimates. It is concluded, therefore, that inverse dispersion modelling is a robust technique for estimating NH3 emission rates. Screening models that can provide a quick and approximate estimate of environmental impacts are a useful tool for impact assessments because they can be used to filter out cases that potentially have a minimal environmental impact allowing resources to be focussed on more potentially damaging cases. The Simple Calculation of Ammonia Impact Limits (SCAIL) model was developed as a screening model to provide an estimate of the mean NH3 concentration and dry deposition rate downwind of an agricultural source. This screening tool, based on the LADD model, was evaluated and calibrated with several experimental datasets and then validated using independent concentration measurements made near sources. Overall SCAIL performed acceptably according to established statistical criteria. This work has identified situations where the concentration predictions of dispersion models are similar and other situations where the predictions are significantly different. Some models are simply not designed to simulate certain scenarios since they do not include the relevant processes or are beyond the limits of their applicability. An example is the LADD model that is not applicable to sources with significant exit velocity since the model does not include a plume-rise parameterisation. The testing of a simple scheme combining a momentum-driven plume rise and increased turbulence at the source improved model performance, but more testing is required. Even models that are applicable and include the relevant process do not always give similar predictions and the reasons for this need to be investigated. AERMOD for example predicts higher concentrations than ADMS for dispersion from mechanically ventilated livestock housing. There is evidence to suggest that ADMS underestimates concentrations in these situations due to a high wind speed threshold. Conversely, there is also evidence that AERMOD overestimates concentrations in these situations due to overestimation at low wind speeds. However, a simple modification to the meteorological pre-processor appears to improve the performance of the model. It is important that these differences between the predictions of these models are taken into account in regulatory assessments. This can be done by applying the most suitable model for the assessment in question or, better still, using multiple or hybrid models.
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Internet fue sólo el principio de los grandes cambios. Desde la invención de la imprenta no ha habido un cambio tecnológico con tantas repercusiones como el de la era de la digitalización. Más aún, con la aparición de los primeros terminales móviles que confirmaron la nueva revolución en esta etapa. Este proyecto se centra en el caso europeo. Para ello, se realiza un análisis que, en primer lugar, abordará el tema económico, en el que se explicarán los factores que han influido positiva y negativamente, tales como: el capitalismo, la globalización, la crisis financiera... Después, se expondrá la cuestión política, haciendo referencia al marco legal europeo, los proyectos y las relaciones internacionales. Otros de los aspectos a tratar (y no menos importantes) serán los relacionados con el desarrollo cultural, el movimiento social y los impactos medioambientales. Finalmente se expondrán los distintos tipos de tecnología a los que han dado lugar estos cambios, y cómo han ido evolucionando a lo largo del tiempo, hasta la aparición de nuevas formas de comunicación. Una vez estudiadas las distintas disciplinas, se podrá “diseñar” una posible perspectiva hacia la que se dirigen las redes móviles e Internet en Europa. En definitiva, conocer de dónde venimos, qué es lo que hacemos y hacia dónde nos dirigimos. Internet was only the beginning of great changes. Since the invention of the printing press there has been such an important technological change as the age of digitization. Moreover, with the appearance of the first mobile terminal which confirmed the new revolution at this stage. This project concentrates on the European case. To do this, an analysis is performed that, in the first place board the economic issue, which will explain the factors that have influenced positively and negatively, such as capitalism, globalization, financial crisis... Then the political question will be discussed, referring to the European legal framework, projects and international relations. Other aspects to be treated (and no less important) are those related to the cultural, social movement and environmental impacts. Finally we will present the different types of technology to which these changes have led, and how they have evolved through time, until the emergence of new forms of communication. After studying the different disciplines, you can "design" a possible perspective towards that target mobile networks and Internet in Europe. In short, knowing where we came from, what we do and where we are going.
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La aplicación de criterios de sostenibilidad ha de entenderse como el procedimiento esencial para la necesaria reconversión del sector de la construcción, que movilizando el 10% de la economía mundial, representa más de la tercera parte del consumo mundial de recursos, en torno al 30-40% del consumo energético y emisiones de gases de efecto invernadero, 30-40% de la generación de residuos y el 12% de todo el gasto en agua dulce del planeta. La presente investigación se enmarca en una estrategia general de promover la evaluación de la sostenibilidad en la edificación en el contexto español, dando un primer paso centrado en la evaluación del comportamiento ambiental. El hilo conductor de la investigación parte de la necesidad de establecer un marco teórico de sostenibilidad, que permita clarificar conceptos y definir criterios de valoración adecuados. Como siguiente paso, la investigación se dirige a la revisión del panorama internacional de normativa e instrumentos voluntarios, con el objetivo de clarificar el difuso panorama que caracteriza a la sostenibilidad en el sector de la edificación en la actualidad y enmarcar la investigación en un contexto de políticas y programaciones ya existentes. El objetivo principal reside en el planteamiento de una metodología de evaluación de los aspectos o impactos ambientales asociados al ciclo de vida de la edificación, aplicable al contexto español, como una de las tres dimensiones que constituyen los pilares básicos de la sostenibilidad. Los ámbitos de evaluación de los aspectos sociales y económicos, para los que no existe actualmente un grado de definición metodológico suficientemente congruente, son adicionalmente examinados, de cara a ofrecer una visión holística de la evaluación. Previo al desarrollo de la propuesta, se aborda, en primer lugar, la descripción de las características básicas y limitaciones de la metodología de Análisis de Ciclo de Vida (ACV), para posteriormente proceder a profundizar en el estado del arte de aplicación de ACV a la edificación, realizando una revisión crítica de los trabajos de investigación que han sido desarrollados en los últimos años. Esta revisión permite extraer conclusiones sobre su grado de coherencia con el futuro entorno normativo e identificar dos necesidades prioritarias de actuación: -La necesidad de armonización, dadas las fuertes inconsistencias metodológicas detectadas, que imposibilitan la comparación de los resultados obtenidos en los trabajos de evaluación. -La necesidad de simplificación, dada la complejidad inherente a la evaluación, de modo que, manteniendo el máximo rigor, sea viable su aplicación práctica en el contexto español. A raíz de la participación en los trabajos de desarrollo normativo a nivel europeo, se ha adquirido una visión crítica sobre las implicaciones metodológicas de la normativa en definición, que permite identificar la hoja de ruta que marcará el escenario europeo en los próximos años. La definición de la propuesta metodológica integra los principios generales de aplicación de ACV con el protocolo metodológico establecido en la norma europea, considerando adicionalmente las referencias normativas de las prácticas constructivas en el contexto español. En el planteamiento de la propuesta se han analizado las posibles simplificaciones aplicables, con el objetivo de hacer viable su implementación, centrando los esfuerzos en la sistematización del concepto de equivalente funcional, el establecimiento de recomendaciones sobre el tipo de datos en función de su disponibilidad y la revisión crítica de los modelos de cálculo de los impactos ambientales. Las implicaciones metodológicas de la propuesta se describen a través de una serie de casos de estudio, que ilustran su viabilidad y las características básicas de aplicación. Finalmente, se realiza un recorrido por los aspectos que han sido identificados como prioritarios en la conformación del escenario de perspectivas futuras, líneas de investigación y líneas de acción. Abstract Sustainability criteria application must be understood as the essential procedure for the necessary restructuring of the construction sector, which mobilizes 10% of the world economy, accounting for more than one third of the consumption of the world's resources, around 30 - 40% of energy consumption and emissions of greenhouse gases, 30-40% of waste generation and 12% of all the fresh water use in the world. This research is in line with an overall strategy to promote the sustainability assessment of building in the Spanish context, taking a first step focused on the environmental performance assessment. The thread of the present research sets out from the need to establish a theoretical framework of sustainability which clarifies concepts and defines appropriate endpoints. As a next step, the research focuses on the review of the international panorama regulations and voluntary instruments, with the aim of clarifying the fuzzy picture that characterizes sustainability in the building sector at present while framing the research in the context of existing policies and programming. The main objective lies in the approach of a methodology for the assessment of the environmental impacts associated with the life cycle of building, applicable to the Spanish context, as one of the three dimensions that constitute the pillars of sustainability. The areas of assessment of social and economic issues, for which there is currently a degree of methodological definition consistent enough, are further examined, in order to provide a holistic view of the assessment. The description of the basic features and limitations of the methodology of Life Cycle Assessment (LCA) are previously addressed, later proceeding to deepen the state of the art of LCA applied to the building sector, conducting a critical review of the research works that have been developed in recent years. This review allows to establish conclusions about the degree of consistency with the future regulatory environment and to identify two priority needs for action: - The need for harmonization, given the strong methodological inconsistencies detected that prevent the comparison of results obtained in assessment works. - The need for simplification, given the inherent complexity of the assessment, so that, while maintaining the utmost rigor, make the practical application feasible in the Spanish context. The participation in the work of policy development at European level has helped to achieve a critical view of the methodological implications of the rules under debate, identifying the roadmap that will mark the European scene in the coming years. The definition of the proposed methodology integrates the general principles of LCA methodology with the protocol established in the European standard, also considering the regulatory standards to construction practices in the Spanish context. In the proposed approach, possible simplifications applicable have been analyzed, in order to make its implementation possible, focusing efforts in systematizing the functional equivalent concept, establishing recommendations on the type of data based on their availability and critical review of the calculation models of environmental impacts. The methodological implications of the proposal are described through a series of case studies, which illustrate the feasibility and the basic characteristics of its application. Finally, the main aspects related to future prospects, research lines and lines of action that have been identified as priorities are outlined.
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Commitment and involvement from the different members of an organization are two key elements for an organization to achieve its environmental excellence. Firstly, businesses are aware of the close relationship between their activities and the environment, for they are not only polluting agents but also agents with the capacity to reduce adverse environmental impacts. Secondly, the fact that employees can play a relevant role in terms of the socially responsible measures to be taken by organizations has started to become an irrefutably important issue. This piece of research is intended to help gain knowledge concerning the attitude of the two main actors in productive activity toward the environmental, that is, employers and employees; as well, this research intends to identify factors determining behaviour towards the environmental. For this, we have gathered the ideas and assessments contained in the discourse of a group of small and medium-sized businesses, large company owners and officers, employees, and work related risk prevention representatives. Qualitative work consisted of in-depth interviews and the creation of discussion groups.
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Increased globalization and outsourcing to developing countries is fostering the interest in supply chain sustainability. From the academic point of view, while environmental impacts of supply chains have been largely analysed, the research on social issues has been scattered and fragmented. This paper thereby sets out to close this gap. We have identified an emerging sphere of knowledge at the interface between sustainable supply chain management, business strategy and international development literature, which seeks to propose innovative strategies for poverty alleviation. The incorporation of impoverished farmers into supply chains is presented here as one of those strategies, and illustrated through a case study on the integration of these farmers in the Senegalese horticulture supply chain.
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La energía eólica, así como otras energías renovables, ha experimentado en la última década un gran auge que va extendiéndose alrededor de todo el mundo, cada vez más concienciado de la importancia de las energías renovables como una fuente alternativa de energía. Se han sumado al reto todos los países acogidos al Protocolo de Kyoto, que a fin de reducir emisiones están potenciando la energía eólica como la fuente de energía renovable hoy día más viable para la generación eléctrica. Brasil alcanzó en 2011 los 1.509 MW instalados, lo que representa el 50% de Latinoamérica, seguido por México con el 31%. Las características del sector eléctrico así como un marco legal favorable y el alto potencial eólico, hacen que la perspectiva de crecimiento en este tipo de energía sea muy favorable durante los próximos años, con estimaciones de unos 20.000 MW para 2020. El asentamiento del sector en el país de algunos de los fabricantes más importantes y los avances en cuanto a eficiencia de los aerogeneradores, mayor aprovechamiento de la energía de los vientos menos intensos, amplía las posibles ubicaciones de parques eólicos permitiendo una expansión grande del sector. El parque eólico objeto del proyecto está ubicado en el estado de Rio Grande do Sul, al sur del país, y está constituido por 33 aerogeneradores de 2,0 MW de potencia unitaria, lo que supone una potencia total instalada de 66 MW. La energía eléctrica generada en él será de 272,8 GWh/año. Esta energía se venderá mediante un contrato de compraventa de energía (PPA, Power Purchase Agreement) adjudicado por el gobierno Brasileño en sus sistemas de subasta de energía. En el proyecto se aborda primeramente la selección del emplazamiento del parque eólico a partir de datos de viento de la zona. Estos datos son estudiados para evaluar el potencial eólico y así poder optimizar la ubicación de las turbinas eólicas. Posteriormente se evalúan varios tipos de aerogeneradores para su implantación en el emplazamiento. La elección se realiza teniendo en cuenta las características técnicas de las máquinas y mediante un estudio de la productividad del parque con el aerogenerador correspondiente. Finalmente se opta por el aerogenerador G97-2.0 de GAMESA. La ejecución técnica del parque eólico se realiza de forma que se minimicen los impactos ambientales y de acuerdo a lo establecido en el Estudio de Impacto Ambiental realizado. Este proyecto requiere una inversión de 75,4 M€, financiada externamente en un 80 % y el 20 % con recursos propios del promotor. Del estudio económico-financiero se deduce que el proyecto diseñado es rentable económicamente y viable, tanto desde el punto de vista técnico como financiero. Abstract Wind energy, as well as other renewable energies, has experienced over the last decade a boom that is spreading around the world increasingly aware of the importance of renewable energy as an alternative energy source. All countries that ratified the Kyoto Protocol have joined the challenge promoting wind energy in order to reduce emissions as the more feasible renewable energy for power generation. In 2011 Brazil reached 1509 MW installed, 50% of Latin America, followed by Mexico with 31%. Electric sector characteristics as well as a favorable legal framework and the high wind potential, make the perspective of growth in this kind of energy very positive in the coming years, with estimates of about 20,000 MW by 2020. Some leading manufacturers have settled in the country and improvements in wind turbines efficiency with less intense winds, make higher the number of possible locations for wind farms allowing a major expansion of the sector. The planned wind farm is located in the state of Rio Grande do Sul, in the south of the Brazil, and is made up of 33 wind turbines of 2,0 MW each, representing a total capacity of 66 MW. The electricity generated, 272,8 GWh/year will be sold through a power purchase agreement (PPA) awarded by the Brazilian government in its energy auction systems. The project deals with the site selection of the wind farm from wind data in the area. These data are studied to evaluate the wind potential and thus optimize the location of wind turbines. Then several types of turbines are evaluated for implementation at the site. The choice is made taking into account the technical characteristics of the machines and a study of the productivity of the park with the corresponding turbine. Finally selected wind turbine is Gamesa G97-2.0. The technical implementation of the wind farm is done to minimize environmental impacts as established in the Environmental Impact Study. This project requires an investment of 75,4 M€, financed externally by 80% and 20% with equity from the promoter. The economic-financial study shows that the project is economically viable, both technically and financially.
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A sustainable manufacturing process must rely on an also sustainable raw materials and energy supply. This paper is intended to show the results of the studies developed on sustainable business models for the minerals industry as a fundamental previous part of a sustainable manufacturing process. As it has happened in other economic activities, the mining and minerals industry has come under tremendous pressure to improve its social, developmental, and environmental performance. Mining, refining, and the use and disposal of minerals have in some instances led to significant local environmental and social damage. Nowadays, like in other parts of the corporate world, companies are more routinely expected to perform to ever higher standards of behavior, going well beyond achieving the best rate of return for shareholders. They are also increasingly being asked to be more transparent and subject to third-party audit or review, especially in environmental aspects. In terms of environment, there are three inter-related areas where innovation and new business models can make the biggest difference: carbon, water and biodiversity. The focus in these three areas is for two reasons. First, the industrial and energetic minerals industry has significant footprints in each of these areas. Second, these three areas are where the potential environmental impacts go beyond local stakeholders and communities, and can even have global impacts, like in the case of carbon. So prioritizing efforts in these areas will ultimately be a strategic differentiator as the industry businesses continues to grow. Over the next forty years, world?s population is predicted to rise from 6.300 million to 9.500 million people. This will mean a huge demand of natural resources. Indeed, consumption rates are such that current demand for raw materials will probably soon exceed the planet?s capacity. As awareness of the actual situation grows, the public is demanding goods and services that are even more environmentally sustainable. This means that massive efforts are required to reduce the amount of materials we use, including freshwater, minerals and oil, biodiversity, and marine resources. It?s clear that business as usual is no longer possible. Today, companies face not only the economic fallout of the financial crisis; they face the substantial challenge of transitioning to a low-carbon economy that is constrained by dwindling natural resources easily accessible. Innovative business models offer pioneering companies an early start toward the future. They can signal to consumers how to make sustainable choices and provide reward for both the consumer and the shareholder. Climate change and carbon remain major risk discontinuities that we need to better understand and deal with. In the absence of a global carbon solution, the principal objective of any individual country should be to reduce its global carbon emissions by encouraging conservation. The mineral industry internal response is to continue to focus on reducing the energy intensity of our existing operations through energy efficiency and the progressive introduction of new technology. Planning of the new projects must ensure that their energy footprint is minimal from the start. These actions will increase the long term resilience of the business to uncertain energy and carbon markets. This focus, combined with a strong demand for skills in this strategic area for the future requires an appropriate change in initial and continuing training of engineers and technicians and their awareness of the issue of eco-design. It will also need the development of measurement tools for consistent comparisons between companies and the assessments integration of the carbon footprint of mining equipments and services in a comprehensive impact study on the sustainable development of the Economy.
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Direct Steam Generation (DSG) in Linear Fresnel (LF) solar collectors is being consolidated as a feasible technology for Concentrating Solar Power (CSP) plants. The competitiveness of this technology relies on the following main features: water as heat transfer fluid (HTF) in Solar Field (SF), obtaining high superheated steam temperatures and pressures at turbine inlet (500ºC and 90 bar), no heat tracing required to avoid HTF freezing, no HTF degradation, no environmental impacts, any heat exchanger between SF and Balance Of Plant (BOP), and low cost installation and maintenance. Regarding to LF solar collectors, were recently developed as an alternative to Parabolic Trough Collector (PTC) technology. The main advantages of LF are: the reduced collector manufacturing cost and maintenance, linear mirrors shapes versus parabolic mirror, fixed receiver pipes (no ball joints reducing leaking for high pressures), lower susceptibility to wind damages, and light supporting structures allowing reduced driving devices. Companies as Novatec, Areva, Solar Euromed, etc., are investing in LF DSG technology and constructing different pilot plants to demonstrate the benefits and feasibility of this solution for defined locations and conditions (Puerto Errado 1 and 2 in Murcia Spain, Lidellin Newcastle Australia, Kogran Creek in South West Queensland Australia, Kimberlina in Bakersfield California USA, Llo Solar in Pyrénées France,Dhursar in India,etc). There are several critical decisions that must be taken in order to obtain a compromise and optimization between plant performance, cost, and durability. Some of these decisions go through the SF design: proper thermodynamic operational parameters, receiver material selection for high pressures, phase separators and recirculation pumps number and location, pipes distribution to reduce the amount of tubes (reducing possible leaks points and transient time, etc.), etc. Attending to these aspects, the correct design parameters selection and its correct assessment are the main target for designing DSG LF power plants. For this purpose in the recent few years some commercial software tools were developed to simulatesolar thermal power plants, the most focused on LF DSG design are Thermoflex and System Advisor Model (SAM). Once the simulation tool is selected,it is made the study of the proposed SFconfiguration that constitutes the main innovation of this work, and also a comparison with one of the most typical state-of-the-art configuration. The transient analysis must be simulated with high detail level, mainly in the BOP during start up, shut down, stand by, and partial loads are crucial, to obtain the annual plant performance. An innovative SF configurationwas proposed and analyzed to improve plant performance. Finally it was demonstrated thermal inertia and BOP regulation mode are critical points in low sun irradiation day plant behavior, impacting in annual performance depending on power plant location.
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Transportation modes produce many external costs such as congestion, accidents, and environmental impacts (pollution, noise and so on). From the microeconomic theory it is well known that in order to maximize social welfare, transportation modes should internalize the marginal costs they produce. Allocative efficiency is achieved when all transportation modes are priced at their social marginal cost. The objective of this research is to evaluate to what extent different passenger transport modes internalize their social marginal costs. This analysis is important since it affects the competitiveness of the different transport modes for a given OD pair. The case study analyzed is the corridor Madrid-Barcelona in Spain and the different transport modes have been considered (cars, buses, high-speed train and air). The research calculates the marginal social cost per user for each transportation mode, and it compares it with the average fare—allowing for the effect of discriminatory taxes—currently paid by the users. The external costs are calculated according to the guidelines established by the European Union. The gap between the marginal social cost and the price paid by users will provide the extra cost per passenger that each transport mode should have to pay for internalizing the external cost it produces. The research shows that external costs already produced by road and air transport modes are much higher than those produced by rail. However, the results show that road transport already internalizes every external costs it produces because users pay high fuel taxes. In other words, although rail transportation produces lower external costs, road transportation pays more than it should on the basis of the social marginal costs. The results of this work might be of help for Europ ean policy actions to be undertaken in the future.
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The complexity of climate change and its evolution during the last few years has a positive impact on new developments and approaches to reduce the emissions of CO2. Looking for a methodology to evaluate the sustainability of a roadway, a tool has been developed. Life Cycle Assessment (LCA) is being accepted by the road industry to measure and evaluate the environmental impacts of an infrastructure, as the energy consumption and carbon footprint. This paper describes the methodology to calculate the CO2 emissions associated with the energy embodied on a roadway along its life cycle, including construction, operations and demolition. It will assist to find solutions to improve the energy footprint and reduce the amount of CO2 emissions. Details are provided of both, the methodology and the data acquisition. This paper is an application of the methodology to the Spanish highways, using a local database. Two case studies and a practical example are studied to show the model as a decision support for sustainable construction in the road industry.
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Las evidencias del impacto sobre el medio ambiente asociado al funcionamiento de las ciudades hacen que sea urgente proponer medidas que reduzcan este consumo y mejoren la eficiencia del metabolismo urbano. La existencia de límites en la disponibilidad de recursos materiales y energéticos, plantea actualmente un reto importante al ser humano: ¿son posibles otras formas de organización más adecuadas a esta condición de limitación? Para dar respuesta, resulta fundamental conocer cómo interactuarán nuestros sistemas urbanos en un modelo económico de continuo desarrollo, con la población que alojan, y si podrán adaptarse a la capacidad de carga limitada del Planeta, evitando futuras situaciones de colapso anunciadas desde distintos ámbitos científicos. En ese contexto, la tesis formula un método de análisis del alojamiento que, mediante la evaluación a largo plazo, permita proponer medidas de intervención para reducir el consumo de recursos asociado a su funcionamiento. Se parte de un enfoque ecológico para definir el alojamiento como una parte fundamental del sistema urbano, que está compuesto por tres elementos: habitantes, viviendas y recursos naturales; por tanto, para reducir los impactos asociados al alojamiento es necesario tener en cuenta la diferente naturaleza de estos elementos y el carácter dinámico de las relaciones que se producen entre ellos. La Ecología, a través del estudio de los ecosistemas, ha identificado estrategias de supervivencia y adaptación ante los cambios y perturbaciones. La similitud entre los elementos de un ecosistema (población y soporte) y los del alojamiento (habitantes, viviendas y recursos naturales) permite verificar que la aplicación de estas estrategias al alojamiento puede conducir a situaciones más deseables en la relación de los sistemas urbanos con su entorno A partir de esta hipótesis, se propone un método de análisis diacrónico1 o a largo plazo, para conocer la evolución en el tiempo del alojamiento a través de la cuantificación de una serie de indicadores descriptivos de los habitantes, las viviendas y los recursos naturales. La aplicación de este método a un sistema urbano permitiría conocer las características de los elementos del sistema y, para un ámbito temporal de futuro, prever su evolución, identificar escenarios no deseables y proponer medidas de intervención que corrijan anticipadamente estas situaciones y eviten impactos ambientales innecesarios. La validación del método de análisis se realiza mediante la aplicación al caso de Madrid en periodo retrospectivo (de 1940 a 2010) A partir del estudio de la evolución en Madrid de los indicadores seleccionados, se proponen medidas de intervención en el alojamiento basadas en estrategias ecológicas que habrían conducido a una evolución alternativa con un impacto menor sobre el medio ambiente que la situación actual. El método de análisis se aplica con carácter prospectivo definiendo tres escenarios de futuro para Madrid hasta 2100. Para cada uno de ellos se analiza la evolución previsible de los indicadores y se proponen diferentes medidas de intervención que, desde el punto de vista ecológico, conducirían a una situación más adecuada. La tesis concluye en el interés de este método de análisis diacrónico que permite estimar posibilidades en la evolución futura del alojamiento, identificar las necesidades de recursos para responder a las demandas de los habitantes y, desde un enfoque ecológico, definir, cuantificar y evaluar posibles medidas de intervención que reduzcan los impactos ambientales. El método, por tanto, es una herramienta de interés para la toma de decisiones en la intervención en el alojamiento y en la planificación urbana a largo plazo. ABSTRACT Evidence of the impact on the environment associated with the operation of cities make it urgent to propose measures to reduce energy consumption and improve the efficiency of urban metabolism. The limited availability of materials and energy resources currently poses a significant challenge to human beings: are more appropriate forms of organization for this limitation possible? In response, it is essential to know how our urban systems with the population they host will interact in an economic model of continuous development and whether they can adapt to the limited endurance capacity of the planet, thus avoiding future collapse situations which are being announced from different scientific fields. In this context, the thesis puts forward a method of housing analysis that by a long term assessment will enable to propose intervention measures to reduce resource consumption associated with its operation. The thesis is based on an ecological approach to identify housing as a fundamental part of the urban system, which is composed of three elements: inhabitants, homes and natural resources. Therefore, in order to reduce the impacts associated with housing it is necessary to consider the characteristics of these elements and the dynamic nature of the relationships among them. Ecology, through the analysis of ecosystems, has identified strategies for survival and adaptation to changes and disturbances. The similarity between the elements of an ecosystem (population and support) and housing (inhabitants, homes and natural resources) enables to verify that the implementation of these strategies to housing can lead to better situations in the relationship existing between urban systems with their environment. From this hypothesis, a diachronic or long term analysis method is proposed to know the evolution of housing over time through the quantification of a descriptive indicators series of inhabitants, homes and natural resources. The implementation of this method to a urban system would allow better knowledge of the characteristics of these elements and forecast their development, identify undesirable scenarios and propose early intervention measures to correct these situations and avoid unnecessary environmental impacts. The validation of the method of analysis has been proved in the city of Madrid for the years 1940-2010. From the analysis of the evolution of the indicators selected, accommodation intervention measures are proposed based on ecological strategies that would have led to an alternative development having less impact on the environment than that of the current situation. The analysis method is implemented prospectively defining three future scenarios for the city of Madrid until 2100. The likely evolution of the indicators are analyzed for each scenario and various intervention measures that would lead to a better situation from an ecological point of view are proposed. The thesis conclusion states the interest of this diachronic analysis method to estimate potential future developments in the housing field, identify resource requirements to meet the demands of the citizens and, from an ecological approach, define, quantify and assess possible intervention measures to reduce environmental impacts. The method, therefore, is an interesting tool for decision-making process as for the intervention in housing and urban planning in the long term.