265 resultados para LCA
Resumo:
Insulating materials in buildings are one of the main factors that should be taken into account when talking about sustainability since with a correct application it could imply important savings for the citizens. In the course of its life, a building requires a series of supplies to perform the duties it has been built for, generating an impact on the environment. The selection of one material or another will establish partly the global environmental impact of the building. Choosing the right insulating material will determine the building's general degree of sustainability, both in its heating savings (energy consumption) and in the environmental impacts caused by its LCA (greenhouse gas emissions). Therefore, we propose to establish guidelines to characterize the insulating material with a better environmental performance in all the stages of its life cycle, taking into account the construction system, the use of the building and its location.
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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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En las siguientes líneas, se podrá encontrar un trabajo perteneciente al Trabajo Fin de Grado realizado por Cristina Parra Cruz. Dicho trabajo tendrá un tema central de estudio y análisis, la lesión del Ligamento Cruzado Anterior (LCA) en el fútbol femenino. El Ligamento Cruzado Anterior es de dos a cuatro veces superior en el fútbol femenino que en el masculino. Independientemente del sexo afectado, esta lesión conlleva un tiempo de baja deportiva elevado y sus complicaciones futuras (riesgo de nueva lesión) deben ser tenidas en cuenta, como también, el mecanismo de producción, factores de riesgo, momento de la lesión, pierna lesionada o tratamiento médico. El principal objetivo de este estudio es presentar el número de lesiones del LCA en diferentes equipos y categorías a lo lardo de dos temporadas (2012-2013 y 2013-2014).
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This paper examined the potentialities of Life Cycle Assessment (LCA) as instrument for policy-support. To this respect, the adoption of an initiative within the Madrid Air Quality Plan (AQP) 2011–2015 regarding the substitution of diesel taxis with hybrid, natural gas and LPG alternatives was studied. Four different scenarios were elaborated, a business-as-usual scenario (BAU), the scenario of the AQP, and two extreme-situation scenarios: all-diesel (ADI) and all-ecologic (AEC). Impacts were characterized according to the ILCD methodology, focusing especially on climate change (CC) and photochemical ozone formation (PO). SimaPro 7.3 was used as analysis and inventory-construction tool. The results indicate that the shift to ecologic alternatives reduced impacts, especially those related to CC and PO. For the complete life cycle, reductions of 13% (CC) and 25% (PO) were observed for AQP against BAU (CC:1365 GgCO2, PO:13336 MgNMVOC). Deeper reductions were observed for AEC (CC:34%, PO:59%), while ADI produced slight increases in impacts if against BAU. The analysis of the use-phase revealed that the central and highest speed zones of the city benefit from the adoption of AQP. This is especially evident in zone 7, with reductions of 16% in CC and 31% in PO respectively against BAU (CCzone1:3443 kgCO2/veh·km, POzone7:11.1 kgNMVOC/veh·km).
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Purpose Concentrating Solar Power (CSP) plants based on parabolic troughs utilize auxiliary fuels (usually natural gas) to facilitate start-up operations, avoid freezing of HTF and increase power output. This practice has a significant effect on the environmental performance of the technology. The aim of this paper is to quantify the sustainability of CSP and to analyse how this is affected by hybridisation with different natural gas (NG) inputs. Methods A complete Life Cycle (LC) inventory was gathered for a commercial wet-cooled 50 MWe CSP plant based on parabolic troughs. A sensitivity analysis was conducted to evaluate the environmental performance of the plant operating with different NG inputs (between 0 and 35% of gross electricity generation). ReCiPe Europe (H) was used as LCA methodology. CML 2 baseline 2000 World and ReCiPe Europe E were used for comparative purposes. Cumulative Energy Demands (CED) and Energy Payback Times (EPT) were also determined for each scenario. Results and discussion Operation of CSP using solar energy only produced the following environmental profile: climate change 26.6 kg CO2 eq/KWh, human toxicity 13.1 kg 1,4-DB eq/KWh, marine ecotoxicity 276 g 1,4-DB eq/KWh, natural land transformation 0.005 m2/KWh, eutrophication 10.1 g P eq/KWh, acidification 166 g SO2 eq/KWh. Most of these impacts are associated with extraction of raw materials and manufacturing of plant components. The utilization NG transformed the environmental profile of the technology, placing increasing weight on impacts related to its operation and maintenance. Significantly higher impacts were observed on categories like climate change (311 kg CO2 eq/MWh when using 35 % NG), natural land transformation, terrestrial acidification and fossil depletion. Despite its fossil nature, the use of NG had a beneficial effect on other impact categories (human and marine toxicity, freshwater eutrophication and natural land transformation) due to the higher electricity output achieved. The overall environmental performance of CSP significantly deteriorated with the use of NG (single score 3.52 pt in solar only operation compared to 36.1 pt when using 35 % NG). Other sustainability parameters like EPT and CED also increased substantially as a result of higher NG inputs. Quasilinear second-degree polynomial relationships were calculated between various environmental performance parameters and NG contributions. Conclusions Energy input from auxiliary NG determines the environmental profile of the CSP plant. Aggregated analysis shows a deleterious effect on the overall environmental performance of the technology as a result of NG utilization. This is due primarily to higher impacts on environmental categories like climate change, natural land transformation, fossil fuel depletion and terrestrial acidification. NG may be used in a more sustainable and cost-effective manner in combined cycle power plants, which achieve higher energy conversion efficiencies.
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The building sector is well known to be one of the key energy consumers worldwide. The renovation of existing buildings provides excellent opportunities for an effective reduction of energy consumption and greenhouse gas emissions but it is essential to identify the optimal strategies. In this paper a multi-criteria methodology is proposed for the comparative analysis of retrofitting solutions. Life Cycle Assessment (LCA) and Life Cycle Cost (LCC) are combined by expressing environmental impacts in monetary values. A Pareto optimization is used to select the preferred strategies. The methodology is exemplified by a case study: the renovation of a representative housing block from the 1960s located in Madrid. Eight scenarios have been proposed, from the Business as Usual scenario (BAU), through Spanish Building Regulation requirements (for new buildings) up to the Passive House standard. Results show how current renovation strategies that are being applied in Madrid are far from being optimal solutions. The required additional investment, which is needed to obtain an overall performance improvement of the envelope compared with the common practice to date, is relatively low (8%) considering the obtained life cycle environmental and financial savings (43% and 45%, respectively).
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Infrared thermography (IRT) is a safe and non-invasive tool used for examining physiological functions based on skin temperature (Tsk) control. Thermograms from 25 anterior cruciate ligament (ACL) surgically operated patients (2 female, 23 male) were taken with a FLIR infrared camera according to the protocol established by the International Academy of Clinical Thermology (IACT). This work consists of 4 studies. Studies 1 and 3 were related to establish the probable thermal difference among different moments of an ACL rupture after surgery: before starting the rehabilitation (P0), at the end of rehabilitation (P1) and 18 months from the end of rehabilitation (P2). For this purpose, on the other hand, studies 2 and 4 were related to establish the skin thermal difference (Tsk) between the injured and the non-injured leg in P0, P1 and P2. Results of the first study showed significant temperature increases in the posterior thigh area between P0 and P1 probably due to a compensatory mechanism. According to this, we can conclude that temperature of the posterior area of the injured and noninjured leg has increased from the first to the last day of the rehabilitation process. In the second study we found significant temperature differences between the injured and non-injured leg in both stages of rehabilitation (p<.01). On the one hand, the temperature of the injured leg is higher in the anterior view and the temperature of the non-injured leg is higher in the posterior view. By the time the patients had recovered from the reconstruction, thermal imbalances should have not been shown between symmetrical parts, but differences seemed to be still latent.. Study 3 shows that temperatures seem to be higher after a year and a half (P2) than in P1. Study 4 shows how thermal values 18 months later seemed to be normalized between both legs. No significant differences were found between the injured leg and the noninjured leg after one year and a half of the rehabilitation process. Considering results from Study 3 and 4 we can conclude that patients seemed to have recovered from a thermal point of view. The temperature in P2 was higher but symmetrical. RESUMEN La termografía infrarroja (IRT) es una herramienta segura y no invasiva utilizada para examinar funciones fisiológicas que se basan en el control de temperatura de la piel (Tsk). Termogramas de 25 pacientes intervenidos quirúrgicamente del ligamento cruzado anterior (LCA) (2 mujeres, 23 hombres) fueron tomadas con una cámara de infrarrojos FLIR de acuerdo con el protocolo establecido por la Academia Internacional de Termología Clínica (IACT). Este trabajo consiste en 4 estudios. Los estudios 1 y 3 describen la diferencia térmica entre los diferentes momentos tras la operación del ligamento cruzado anterior: antes de comenzar la rehabilitación (P0), al final de la rehabilitación (P1) y 18 meses tras finalizar la rehabilitación (P2). Por otra parte, los estudios 2 y 4 describen la diferencia de temperatura de la piel (Tsk) entre la pierna lesionada y la pierna no lesionada en P0, P1 y P2. Los resultados del primer estudio mostraron aumentos significativos de temperatura en la zona posterior de los muslos entre P0 y P1, probablemente debido a un mecanismo de compensación. De acuerdo con esto, se puede concluir que la temperatura de la zona posterior de la pierna lesionada y no lesionada se ha incrementado desde el primero hasta el último día del proceso de rehabilitación. En el segundo estudio se encontraron diferencias significativas de temperatura entre la pierna lesionada y no lesionada en ambas etapas de la rehabilitación (p<.01). Por un lado, la temperatura de la pierna lesionada es mayor en la vista anterior. Por otro lado, la temperatura de la pierna no lesionada es mayor en la vista posterior. Una vez que los pacientes se han recuperado de todo el proceso, no deberían existir desequilibrios térmicos entre partes simétricas del cuerpo, pero las diferencias todavía estaban latentes. El tercer estudio muestra que la temperatura es más alta en P2 que en P1. El cuarto estudio muestra cómo los valores térmicos entre ambas piernas en P2 se han normalizado entre ambas piernas. No se encontraron diferencias significativas entre la pierna lesionada y la pierna no lesionada después de 18 meses tras el proceso de rehabilitación. Considerando los resultados del studio 3 y 4, podemos concluir que se ha llegado a la recuperación total desde un punto de vista térmico. La temperatura es más elevada en P2 pero simétrica.
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The pregnane X receptor (PXR) is the molecular target for catatoxic steroids such as pregnenolone 16α-carbonitrile (PCN), which induce cytochrome P450 3A (CYP3A) expression and protect the body from harmful chemicals. In this study, we demonstrate that PXR is activated by the toxic bile acid lithocholic acid (LCA) and its 3-keto metabolite. Furthermore, we show that PXR regulates the expression of genes involved in the biosynthesis, transport, and metabolism of bile acids including cholesterol 7α-hydroxylase (Cyp7a1) and the Na+-independent organic anion transporter 2 (Oatp2). Finally, we demonstrate that activation of PXR protects against severe liver damage induced by LCA. Based on these data, we propose that PXR serves as a physiological sensor of LCA, and coordinately regulates gene expression to reduce the concentrations of this toxic bile acid. These findings suggest that PXR agonists may prove useful in the treatment of human cholestatic liver disease.
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Hepatic hydroxylation is an essential step in the metabolism and excretion of bile acids and is necessary to avoid pathologic conditions such as cholestasis and liver damage. In this report, we demonstrate that the human xenobiotic receptor SXR (steroid and xenobiotic receptor) and its rodent homolog PXR (pregnane X receptor) serve as functional bile acid receptors in both cultured cells and animals. In particular, the secondary bile acid derivative lithocholic acid (LCA) is highly hepatotoxic and, as we show here, a metabolic substrate for CYP3A hydroxylation. By using combinations of knockout and transgenic animals, we show that activation of SXR/PXR is necessary and sufficient to both induce CYP3A enzymes and confer resistance to toxicity by LCA, as well as other xenotoxicants such as tribromoethanol and zoxazolamine. Therefore, we establish SXR and PXR as bile acid receptors and a role for the xenobiotic response in the detoxification of bile acids.
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A obtenção de etanol a partir de rotas alcoolquímicas consagradas gera resíduos com potencial de aproveitamento, tanto em outros setores produtivos como no ciclo produtivo do próprio combustível. Este é o caso de torta de filtro e vinhaça. A vinhaça em particular costuma ser devolvida ao campo com o intuito de ajustar teores nutricionais do solo no cultivo da cana. No entanto, estudos ambientais destacam que esta alternativa traz efeitos negativos sobre os meios receptores (água e solo), condição que abre a perspectiva para exploração de usos alternativos dessas substâncias. Este estudo se propôs a contribuir para o tema ao avaliar de forma sistêmica o desempenho ambiental de duas alternativas de reaproveitamento de vinhaça: (i) reuso no campo em processos de fertirrigação, alternativa consolidada no Brasil, e (ii) reuso da fração líquida da vinhaça em etapas diversas do processo industrial de obtenção de etanol. Em qualquer das situações fez-se uso da técnica de Avaliação de Ciclo de Vida - ACV para proceder tal verificação. A análise ambiental da prática de reuso de vinhaça e torta para fertirrigação foi conduzida a partir da comparação de cenários que consideraram a forma de suprimento de nutrientes para a cana e o método de colheita. A avaliação de impactos ocorreu em dois níveis: quanto ao consumo de recursos, a partir de Primary Energy Demand (PED); e em termos de emissões para o ambiente por meio da elaboração do Perfil Ambiental. Uma Análise de Sensibilidade foi também realizada para verificar o efeito de oscilações dos teores de Nitrogênio (N), Fósforo (P) e Potássio (K) na composição da vinhaça sobre os resultados obtidos, caso da primeira alternativa. Concluiu-se para esse caso que a substituição parcial de fertilizantes químicos por vinhaça traz aumento da Demanda de Energia Primária global para ambos os métodos de colheita. Em termos de Perfil Ambiental, a comparação entre cenários das mesmas práticas de manejo mostrou que a troca de adubos por vinhaça e torta é positiva para o desempenho ambiental do etanol por reduzir impactos quanto a Mudanças Climáticas (CC), Acidificação Terrestre (TA) e Toxicidade Humana (HT). Por outro lado, o tratamento de vinhaça para reposição de água na etapa industrial resultou em aumento global das contribuições para as categorias acima mencionadas além de incrementos para Eutrofização de água doce (FEut) e Ecotoxicidade de água doce (FEC), a despeito de ser constatada a redução de 45% quanto a Depleção de água (WD). Os aumentos no impacto se deveram principalmente aos efeitos negativos causados durante a produção do CaO usado no processo de tratamento da vinhaça. No entanto, a substituição deste insumo por NaOH só representou melhora em termos de CC. Pode-se concluir que a reutilização de vinhaça e de torta de filtro como complemento nutricional para o cultivo de cana-de-açúcar resultou em uma alternativa mais adequada de reaproveitamento do que o se este fluído fosse reutilizado para suprir parte da demanda hídrica de processo, mesmo quando o consumo de água na etapa industrial tenha inexoravelmente se reduzido a partir da implantação dessa medida.
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A construção civil é responsável por relevante impacto ao meio ambiente, da extração das materiais-primas até a disposição dos seus resíduos em aterros. A avaliação do ciclo de vida (ACV) é uma ferramenta que possibilita a estimativa dos impactos ambientais potenciais do setor de forma sistemática. A simplificação da ACV, pelo uso de dados secundários e redução do escopo do estudo, facilita sua implementação como ferramenta de promoção da sustentabilidade. O objetivo dessa dissertação é estimar faixas dos cinco principais indicadores do setor de blocos de concreto do mercado brasileiro pela simplificação da ACV: consumo de materiais, energia incorporada, emissão de CO2, água e geração de resíduos. Este estudo foi o piloto do Projeto ACV Modular, iniciativa do Conselho Brasileiro de Construção Sustentável em parceria da Associação Brasileira de Cimento Portland e da Associação Brasileira da Indústria de Blocos de Concreto. O inventário foi desenvolvido com 33 fábricas localizadas em diferentes regiões do Brasil, estas sendo responsáveis por aproximadamente 50% da produção nacional. Os produtos selecionados foram blocos para pavimentação e alvenaria (estruturais e de vedação) considerados mais representativos no mercado. A fronteira do sistema adotada foi do berço ao portão da fábrica. O indicador de consumo de materiais não foi apresentado para garantir a confidencialidade dos dados das empresas, pois o teor de cimento foi dado direto informado no formulário. O indicador de resíduos não pode ser gerado devido a diferentes interpretações adotadas pelos fabricantes ao registrar seus dados. O indicador de água, apesar de incluir todo o consumo informado pela fábrica, apresentou valores muito baixos, alguns próximos a zero. O consumo de cimento, não o teor de clínquer, foi responsável por parcela significativa do CO2 e da energia incorporada do bloco, com participação de 62 a 99% das emissões de CO2. Assim, entre as empresas analisadas, mesmo com igual rota tecnológica, os insumos utilizados, a formulação do concreto, a eficiência de compactação da vibro prensa e o sistema produtivo tiveram maior influência nos indicadores de materiais, energia e CO2.
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This work addresses the optimization of ammonia–water absorption cycles for cooling and refrigeration applications with economic and environmental concerns. Our approach combines the capabilities of process simulation, multi-objective optimization (MOO), cost analysis and life cycle assessment (LCA). The optimization task is posed in mathematical terms as a multi-objective mixed-integer nonlinear program (moMINLP) that seeks to minimize the total annualized cost and environmental impact of the cycle. This moMINLP is solved by an outer-approximation strategy that iterates between primal nonlinear programming (NLP) subproblems with fixed binaries and a tailored mixed-integer linear programming (MILP) model. The capabilities of our approach are illustrated through its application to an ammonia–water absorption cycle used in cooling and refrigeration applications.
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Presentation submitted to PSE Seminar, Chemical Engineering Department, Center for Advanced Process Design-making (CAPD), Carnegie Mellon University, Pittsburgh (USA), October 2012.
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In this work, we analyze the effect of demand uncertainty on the multi-objective optimization of chemical supply chains (SC) considering simultaneously their economic and environmental performance. To this end, we present a stochastic multi-scenario mixed-integer linear program (MILP) with the unique feature of incorporating explicitly the demand uncertainty using scenarios with given probability of occurrence. The environmental performance is quantified following life cycle assessment (LCA) principles, which are represented in the model formulation through standard algebraic equations. The capabilities of our approach are illustrated through a case study. We show that the stochastic solution improves the economic performance of the SC in comparison with the deterministic one at any level of the environmental impact.
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Poster presented in the 24th European Symposium on Computer Aided Process Engineering (ESCAPE 24), Budapest, Hungary, June 15-18, 2014.