931 resultados para mercury abatement
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贵州省是我国最重要的汞工业基地,境内分布着大量的汞矿床,汞金属储量88000 t,占全国总储量近80%。汞矿开采、冶炼历史悠久,大规模的汞矿开采冶炼活动都已经停止。但是,由于汞矿区偏僻的自然地理位置、落后的经济水平和近期金属汞价格的攀升,这些地区仍然存在着较大规模的土法炼汞活动。大面积的土法炼汞活动和长期的大规模汞矿开采冶炼活动,给矿区生态环境造成了严重的汞污染。土法炼汞工艺十分落后,冶炼过程向周围大气释放大量的汞,而土法炼汞工人也必然会遭受严重的汞蒸气暴露。释放到大气的汞在进入周围环境后,在自然条件下通过微生物活动,会转化为毒性、生物有效性更强的甲基汞,并通过食物链富集放大,最终对矿区居民的身体健康构成一定的威胁。 本文选择贵州省务川汞矿区、万山汞矿区和铜仁垢溪、老屋场土法炼汞地区,进行了土法炼汞的汞释放量估算、汞矿地区环境汞污染调查及炼汞工人和矿区居民汞暴露调查和健康风险评价,系统阐述了贵州典型土法炼汞地区汞的生物地球化学循环特征及人体汞暴露评价。 1. 务川和铜仁垢溪地区的土法炼汞活动是当地大气的最主要人为释汞源。务川汞矿区土法炼汞的平均释汞因子为18.2%(6.9-32.1%),土法炼汞活动每年向大气排汞3.7-9.6 t;铜仁垢溪地区土法炼汞的平均释汞因子为9.8%(6.6-14.5%),土法炼汞活动每年向大气排汞1.3-2.7 t。 2. 务川汞矿区大面积的土法炼汞活动和长期大规模的汞矿活动以及垢溪、老屋场地区的土法炼汞活动,给当地的大气、地表水体和土壤造成了严重的汞污染,而汞污染程度受汞矿开采冶炼活动的历史和规模的影响显著。务川汞矿区大气汞浓度空间变化很大(7-40000 ng•m-3),受矿业活动影响的区域,大气汞含量明显升高;重污染区大气汞平均浓度为15000 ng•m-3,轻污染区为120 ng•m-3,对照区为24 ng•m-3。务川矿区地表水体的总汞含量的变化范围为43-2100 ng•L-1,总甲基汞含量变化范围为0.30-1.1 ng•L-1;垢溪、老屋场地区地表水体总汞含量的变化范围为92-2300 ng•L-1,总甲基汞含量变化范围为2.6-7.9 ng•L-1,地表水体显示了极强的甲基化能力。颗粒态汞占地表水体总汞含量的绝大部分比例,是矿区地表水体汞迁移的主要方式;而甲基汞则以溶解态为主。务川汞矿区土壤总汞含量的变化范围为1.3-360 mg•kg-1,垢溪、老屋场地区土壤总汞含量的变化范围为0.18-47.5 mg•kg-1,土壤剖面表层土壤汞的富集表明大气汞的沉降是土壤汞的重要来源,而土壤pH、有机质含量和土地利用类型影响着土壤中汞的迁移和富集。 3. 务川汞矿区土法炼汞工人尿汞含量的平均值高达1060 g•g-1 Cr,铜仁垢溪地区炼汞工人尿汞含量的平均值为347 g•g-1 Cr,铜仁老屋场地区炼汞工人尿汞含量的平均值为917 g•g-1 Cr,土法炼汞工人尿汞平均含量远远超过世界卫生组织规定的职业暴露人群的最大允许值-50 g•g-1 Cr,说明土法炼汞工人遭受严重的汞蒸气暴露。部分土法炼汞工人已经表现出轻度慢性汞中毒的症状,其肾脏已经遭受到一定程度的损伤。铜仁垢溪地区一般居民尿汞的平均值为40.0 g•g-1 Cr,铜仁老屋场地区一般居民尿汞含量的平均值为66.2 g•g-1 Cr,万山汞矿区大水溪居民尿汞含量的平均值为56.9 g•g-1 Cr,说明土法炼汞地区一般居民也遭受一定的汞蒸气暴露。对照区人群尿汞含量的平均值为1.30 g•g-1 Cr,万山下场溪村居民尿汞含量的平均值为2.5 g•g-1 Cr,其尿汞水平与对照组接近。 4. 食用大米是汞矿区居民甲基汞暴露的主要途径。万山汞矿区大水溪、下场溪和报溪3个村庄居民头发总汞含量的几何平均值分别为7.3、1.9和2.3 g•g-1,而头发甲基汞的平均含量分别为2.8、1.3和1.5 g•g-1,说明万山汞矿区居民存在一定程度的汞暴露。3个村庄居民食用大米总汞的平均含量分别为58.5、21.3和33.1 ng•g-1,大米甲基汞的平均含量分别为14.6、5.7和4.0 ng•g-1。居民食用的蔬菜、猪肉和饮水也表现出很高的总汞含量,但是甲基汞含量很低。3个村庄居民食用大米的摄入量占总甲基汞摄入量的平均比例分别为97.5%、94.1%和93.5%,且不同参与者每日通过食用大米的甲基汞摄入量和对应的头发甲基汞含量之间存在显著的相关关系 (r=0.65, p<0.01),这证实了居民头发甲基汞的来源确实是食用大米,食用大米是汞矿区居民甲基汞暴露的主要途径。 5. 铜仁垢溪、老屋场地区炼汞工人头发甲基汞的平均含量分别为5.05 g•g-1(2.35-10.6 g•g-1)和5.63 g•g-1(2.54-9.55 g•g-1),而一般居民头发甲基汞的平均含量分别为3.53 g•g-1(1.87-5.65 g•g-1)和4.01 g•g-1(2.29-9.23 g•g-1)。万山汞矿区大水溪、下场溪和报溪3个村庄居民头发甲基汞的平均含量分别为2.8、1.3和1.5 g•g-1。务川汞矿区土法炼汞工人和居民的头发甲基汞含量的变化范围为0.47-5.69 μg•g-1。对照组头发甲基汞的平均含量为0.65 g•g-1,变化范围为0.26¬-1.38 g•g-1。食用大米甲基汞摄入量的估算表明,铜仁垢溪和老屋场地区部分居民的甲基汞摄入量已经超过世界卫生组织2003年制定的标准-0.23 g•d-1•kg-1,汞矿区大部分人群的甲基汞摄入量超过了美国环保局的推荐值-0.1 g•d-1•kg-1 (USEPA, 1997),而对照区居民的甲基汞摄入量均没有超过这一推荐值,表明铜仁垢溪和老屋场地区居民存在一定的甲基汞暴露风险,而其他汞矿区人群也存在通过食用大米暴露甲基汞的潜在风险。
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北欧和北美的研究发现水库是典型的汞敏感生态系统,新建水库而引起的鱼的甲基汞污染问题已经受到科学家的高度重视,而我国在这方面的研究比较薄弱。本论文以乌江流域上游的东风水库为研究对象,于夏季(2007 年8月)、冬季(2007 年12 月)和春季(2008年4月)分别对水库不同深度分层水体、沉积物间隙水、沉积柱剖面中不同形态汞的含量、分布特征以及迁移转化规律进行了详细的研究。研究结果发现: 1.东风水库水体中各种形态汞浓度均表现出季节性变化。总汞(THg)浓度变化范 围为1.1-2.3ng/L,平均为1.6ng/L;溶解态汞(THg)浓度变化范围为0.3-1.3ng/L,平均为0.6ng/L;颗粒态汞(PHg)浓度范围为0.3-1.5ng/L,平均为0.8ng/L;活性汞(RHg)浓度范围为0.2-0.6ng/L,平均为0.4ng/L;总甲基汞(TMHg)浓度变化范 围为0.04-1.01ng/L,平均为0.27ng/L;溶解态甲基汞(DMHg)浓度变化范围为0.03-0.48ng/L,平均为0.12ng/L;颗粒态甲基汞汞(PMHg)浓度范围为0.01-0.7ng/L,平均为0.16ng/L。 2.东风水库水体颗粒态总汞与总汞呈极显著相关,说明东风水库水体的颗粒态汞强烈影响着总汞迁移和分布。水库水体总甲基汞与溶解态甲基汞汞和颗粒态甲基汞之间存在极显著正线性相关,证明水库水体中的甲基汞的产生和迁移与溶解态甲基汞和颗粒态甲基汞均有着密切的关系。但是,水体甲基汞与总汞之间并不存在相关性。 3.东风水库水体夏季溶解态汞、活性汞、溶解态甲基汞浓度均远高于冬春两季,除了外源异重径流输入的影响外,很大程度与夏季水库底部缺氧环境密不可分。沉积物释放大量吸附的汞进入水体,造成水体溶解态汞、活性汞、溶解态甲基汞的升高。 4.东风水库沉积物间隙水中总汞和甲基汞浓度出现明显的季节性变化,夏季大于冬春两季。沉积物甲基汞的浓度分布与沉积物中有机质含量相关性明显(r=0.219*,n=133)。东风水库沉积物中甲基汞的含量随沉积物深度增加浓度梯度不明显。 5.东风水库沉积物总汞含量基本没有季节变化,浓度变化范围为97-354ng/g,平均为180ng/g。东风水库沉积物中总汞含量大大高于其他未受污染地区水库沉积物中总汞含量。甲基汞含量变化范围为0.1-5.5ng/g,平均为2.1ng/g 。 6.东风水库沉积物间隙水中总汞、甲基汞浓度均显著高于其上覆水体的总汞和甲基汞的浓度,二者之间存在显著的浓度梯度,沉积物中总汞和甲基汞的释放是水库水体的重要来源。
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本研究选择有代表性的陕西省潼关县(小秦岭地区)采金地区作为研究对象,从环境地球化学的角度出发,研究了该地区由于受采金活动的影响后,大气、水体、土壤以及农作物中总汞和甲基汞的分布,探讨汞在采金地区环境中迁移、转化和富集的环境地球化学行为和规律,并估算了渲关县及全国在过去二十多年里,由混汞法炼金活动向环境释放汞的总量,最后对混汞法采金地区的环境管理提出可行性建一议。通过本论文的详细研究,主要得出以下结论:1.潼关县辖区大气汞的分布呈明显的空间梯度关系,炼金厂密集区大气汞含量明显高于其它地区,距离炼金厂越远,大气汞含量越低。大型炼金厂混汞提金车间内的平均大气汞浓度为18,047ng/m~3,最高达33,080ng/m~3;距离炼金厂密集区较近和较远的居民区的平均大气汞浓度分别为385ng/m~3和77ng/m~3;而一些偏远地区大气汞的平均浓度降至29ng/m~3,受炼金活动影响较 小的黄河沿岸背景区的平均大气汞浓度只有2ng/m~3。通过估算,潼关县炼金矿工汞蒸气的平均摄入量高达72,804~75,268ng/d,而当地非矿工居民(成人)每天的摄入量也有924~4,620ng。2.潼关县内泉水和井水中总汞的平均浓度有329.2ng/L,其中各形态汞的浓度都相对较高,说明金矿地区的汞背景值可能较高,且地下水也可能受到一定程度的汞污染;冷暖两季水样中溶解态汞浓度和暖季的甲基汞浓度要比泉水和井水中的溶解态汞和甲基汞浓度分别高出几倍,其它形态汞则要高出几百倍;水样中的活性汞和溶解态汞浓度表现出极显著的相关关系;冷季水样的活性汞和溶解态汞平均浓度要略高于暖季的水样,而颗粒态汞恰恰相反;两季采集的一些水样中活性汞在溶解态汞中占有较高的比例,但总汞均以颗粒态为主,大多超过50%。3.冷暖两季沉积物中平均总汞浓度分别高达151.1和44.6μg/g,甲基汞平均浓度分别为7.1和3.6ng/g,而暖季沉积物中总汞与甲基汞含量表现出极显著的相关关系;水体颗粒物和沉积物主要来源于炼金厂排出的废渣和尾矿,拥有较高的重金属(Hg、Fe、Mn和Cu)含量,且两者之间体现出一定的继承关系,但颗粒物由于粒径小,表面积大,含有机颗粒多,吸附能力强,所以其中的重金属含量要明显高于沉积物中的重金属含量;颗粒物中汞含量与Fe、Mn、Cu的含量之间均表现出极显著的相关性,而沉积物中汞含量仅与Cu含量之间有一定的相关性,与其它重金属含量的相关性不明显。4.潼关县辖区金矿石中汞的平均含量是69.2ng/g,而炼金尾矿中汞的平均含量竟高达628,4林吮,高出原矿石样中汞平均含量10,000倍,其它重金属(Fe、Mn、Cu)由于受炼金活动影响较小,其含量变化并不十分明显;黄土由于自身的特殊质地和性质,受炼金活动的干扰较小,其中的各重金属含量能够较好的反映其背景含量水平;撞关地区采集的土壤样品中总汞和甲基汞含量均要比黄土中的含量高约50倍,而其它重金属含量与黄土背景值无明显差异;土壤中甲基汞在总汞含量中所占比例较小(分布在0.001%~0.57%之间),说明潼关地区土壤中汞的甲基化水平较低。5.苔鲜样品中的高汞含量反映了采金地区较高的大气汞沉降水平;河流水藻中高含量的总汞和甲基汞体现出汞在生物体内超强的富集作用;潼关县大多数农作物样品中的汞主要来源于大气,且几乎所有样品的汞含量都严重超出国家食用标准,最高超标倍数达到60;农作物中甲基汞含量占总汞的比例在0.12%~12.34%之间波动,其中蔬菜类作物的甲基汞比例要高于粮食作物,而总体来说,作物体内的总汞和甲基汞含量之间表现出一定的负相关关系;通过估算,潼关县居民由于粮食作物(小麦)的食用每天摄入的总汞量高达54,72Ong,要高于当地居民(非矿工)通过呼吸吸入的汞蒸气量,且已超出国际上对人体汞摄入量标准的有关规定。6.潼关县水体、沉积物、土壤以及农作物中的甲基汞含量相对总汞而言,都表现了相对较低的水平,原因可能是受石英脉型金矿地区地质背景的影响,大量存在的Fe、Mn类化合物对离子态汞有着较强的束缚能力,减缓或抑制了甲基化的发生。7.通过混汞法生产黄金的产量和汞释放因子的调研和确定,估算在1980~2003年期间,全国混汞炼金行业向环境释放汞累计达1476.6t,其中约有78%进入大气;而仅潼关县就有116.5t,约占全国的7.9%:目前(1996年以后),由于混汞法工艺的改进,汞的释放量大大降低,全国混汞炼金行业平均每年释放汞约30t,憧关县平均每年有3.9t,约占全国年平均释放量的13%。
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The addition of a suitable amount of PPh3 to PdCl2 or PdCl2(PhCN)(2) in situ can considerably increase the catalytic activity in the hydrogenation of nitrobenzene, while the catalytic activities of PdCl2 (reduced)+PPh3, PdCl2(PPh3)(2) and Pd(PPh3)(4) are very poor. The poisoning of catalyst by mercury indicates that the catalytically active species are composed of Pd(0) colloidal particles. Transmission electron micrographs show that the size of nanometric Pd(0) particles of PdCl2 with PPh3 added in situ is smaller than that of PhCl2(PPh3) or PdCl2 (reduced)+PPh3. A synergic effect of bimetallic catalysts such as PdCl2+nPPh(3)+NiCl2 (n= 0.5, 1) and PdCl2(PhCN)(2)+PPh3+FeCl3 gives rise to a further increase in the catalytic activity.
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Tese de Doutoramento apresentada à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Doutror em Ciências da Terra.
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O carvão e outros combustíveis fósseis, continuarão a ser, por décadas, a principal matéria-prima energética para as Centrais Térmicas, não obstante os esforços para, dentro do possível, substituir os combustíveis fósseis por fontes de energia renovável.Tal como está, hoje, bem documentado, a produção de gases com efeito estufa (GEE), designadamente CO2, resulta da combustão dos ditos combustíveis fósseis, sendo que se espera ser possível mitigar substancialmente a emissão de tais gases com a aplicação das chamadas Tecnologias Limpas do Carvão.Há, pois, necessidade de promover o abatimento do CO2 através de Tecnologias de Emissão Zero ou Tecnologias Livres de Carbono, incluindo designadamente a Captura, o Transporte e a Sequestração geológica de CO2 correspondentes ao que é costume designar por Tecnologias CAC (Captação e Armazenamento de Carbono). De facto, tais tecnologias e, designadamente, o armazenamento geológico de CO2 são as únicas que, no estado actual do conhecimento, são capazes de permitir que se cumpram as metas do ambicioso programa da EU para a energia e o ambiente conhecido por “20 20 para 2020” em conjugação com os aspectos económicos das directivas relativas ao Comércio Europeu de Licenças de Emissão – CELE (Directivas 2003/87/EC, 2004/101/EC e 2009/29/EC).A importância do tema está, aliás, bem demonstrada com o facto da Comissão Europeia ter formalmente admitido que as metas supracitadas serão impossíveis de atingir sem Sequestração Geológica de CO2. Esta é, pois, uma das razões de ter sido recentemente publicada a Directiva Europeia 2009/31/EC de 23 de Abril de 2009 expressamente dedicada ao tema do Armazenamento Geológico de CO2.Ora, a questão do armazenamento geológico de CO2 implica, para além das Tecnologias CAC acima mencionadas e da sua viabilização em termos tanto técnicos como económicos, ou seja, neste último aspecto, competitiva com o sistema CELE, também o conhecimento, da percepção pública sobre o assunto. Isto é, a praticabilidade das Tecnologias CAC implica que se conheça a opinião pública sobre o tema e, naturalmente, que face a esta realidade se prestem os esclarecimentos necessários como, aliás, é reconhecido na própria Directiva Europeia 2009/31/EC.Dado que a Fundação Fernando Pessoa / Universidade Fernando Pessoa através do seu Centro de Investigação em Alterações Globais, Energia, Ambiente e Bioengenharia – CIAGEB tem ultimado um Projecto de Engenharia relativo à Sequestração Geológica de CO2 nos Carvões (Metantracites) da Bacia Carbonífera do Douro – o Projecto COSEQ, preocupou-se naturalmente, desde o início, com o lançamento de inquéritos de percepção da opinião pública sobre o assunto.Tal implicou, nesta fase, a tradução para português e o lançamento do inquérito europeu ACCSEPT que não tinha sido ainda formalmente lançado de forma generalizada entre nós. Antes, porém, de lançar publicamente tal inquérito – o que está actualmente já em curso – resolveu-se testar o método de lançamento, a recolha de dados e o seu tratamento com uma amostra correspondente ao que se designou por Comunidade Fernando Pessoa, i.e. o conjunto de docentes, discentes, funcionários e outras pessoas relacionadas com a Universidade Fernando Pessoa (cerca de 5000 individualidades).Este trabalho diz, precisamente, respeito à preparação, lançamento e análise dos resultados do dito inquérito Europeu ACCSEPT a nível da Comunidade Fernando Pessoa. Foram recebidas 525 respostas representando 10,5% da amostra. A análise de resultados foi sistematicamente comparada com os obtidos nos outros países europeus, através do projecto ACCSEPT e, bem assim, com os resultados obtidos num inquérito homólogo lançado no Brasil. The use of coal, and other fossil fuels, will remain for decades as the main source of energy for power generation, despite the important efforts made to replace, as far as possible, fossil fuels with renewable power sources.As is well documented, the production of Greenhouse Gases (GHG), mainly CO2, arises primarily from the combustion of fossil fuels. The increasing application of Clean Coal Technologies-CCTs, is expected to mitigate substantially against the emission of such gases.There is consequently a need to promote the CO2 abatement through Zero Emission (Carbon Free) Technologies - ZETs, which includes CO2 capture, transport and geological storage, i.e. the so-called CCS (Carbon, Capture and Storage) technologies. In fact, these technologies are the only ones that are presently able to conform to the ambitious EU targets set out under the “20 20 by 2020” EU energy and environment programme, jointly with the economic aspects of the EU Directives 2003/87/EC, 2004/101/EC and 2009/29/EC concerned with the Greenhouse Gas Emissions Allowance Trading Scheme – ETS scheme. The European Commission formal admission that the referred targets will be impossible to reach without the implementation and contribution of geological storage clearly demonstrate the importance of this particular issue, and for this reason the EC Directive 2009/31/EC of April 23, 2009 on Geological Storage of CO2 was recently published.In considering the technical and economical viabilities of CCS technologies, the latter in competition with the ETS scheme, it is believed that public perception will dictate the success of the development and implementation of CO2 geological storage at a large industrial level. This means that, in order to successfully implement CCS technologies, not only must public opinion be taken into consideration but objective information must also be provided to the public in order to raise subject awareness, as recognized in the referred Directive 2009/31/EC.In this context, the Fernando Pessoa Foundation / University Fernando Pessoa, through its CIAGEB (Global Change, Energy, Environment and Bioengineering) RDID&D Unit, is the sponsor of an Engineering Project for the Geological Sequestration of CO2 in Douro Coalfield Meta-anthracites - the COSEQ Project, and is therefore also engaged in public perception surveys with regards to CCS technologies.At this stage, the original European ACCSEPT inquiry was translated to Portuguese and submitted only to the “Fernando Pessoa Community” - comprising university lecturers, students, other employees, as well as, former students and persons that have a professional or academic relationship with the university (c. 5000 individuals). The results obtained from this first inquiry will be used to improve the survey informatics system in terms of communication, database, and data treatment prior to resubmission of the inquiry to the Portuguese public at large.The present publication summarizes the process and the results obtained from the ACCSEPT survey distributed to the “Fernando Pessoa Community”. 525 replies, representing 10.5% of the sample, have been received and analysed. The assessment of the results was systematically compared with those obtained from other European Countries, as reported by the ACCSEPT inquiry, as well as with those from an identical inquiry launched in Brazil.
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Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Ciências Farmacêuticas
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In the Spallation Neutron Source (SNS) facility at Oak Ridge National Laboratory (ORNL), the deposition of a high-energy proton beam into the liquid mercury target forms bubbles whose asymmetric collapse cause Cavitation Damage Erosion (CDE) to the container walls, thereby reducing its usable lifetime. One proposed solution for mitigation of this damage is to inject a population of microbubbles into the mercury, yielding a compliant and attenuative medium that will reduce the resulting cavitation damage. This potential solution presents the task of creating a diagnostic tool to monitor bubble population in the mercury flow in order to correlate void fraction and damage. Details of an acoustic waveguide for the eventual measurement of two-phase mercury-helium flow void fraction are discussed. The assembly’s waveguide is a vertically oriented stainless steel cylinder with 5.08cm ID, 1.27cm wall thickness and 40cm length. For water experiments, a 2.54cm thick stainless steel plate at the bottom supports the fluid, provides an acoustically rigid boundary condition, and is the mounting point for a hydrophone. A port near the bottom is the inlet for the fluid of interest. A spillover reservoir welded to the upper portion of the main tube allows for a flow-through design, yielding a pressure release top boundary condition for the waveguide. A cover on the reservoir supports an electrodynamic shaker that is driven by linear frequency sweeps to excite the tube. The hydrophone captures the frequency response of the waveguide. The sound speed of the flowing medium is calculated, assuming a linear dependence of axial mode number on modal frequency (plane wave). Assuming that the medium has an effective-mixture sound speed, and that it contains bubbles which are much smaller than the resonance radii at the highest frequency of interest (Wood’s limit), the void fraction of the flow is calculated. Results for water and bubbly water of varying void fraction are presented, and serve to demonstrate the accuracy and precision of the apparatus.
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Over the last 30 years, western European Song Thrush populations have declined with the steepest decline recorded on British farmland. Changes in agricultural practices have been implicated in these population declines. Ireland is an agriculturally dominated landscape but changes in agriculture here have occurred on a relatively slower rate and scale. Little is known about the ecology of the Song Thrush in Ireland, even though it is not classified as a species of conservation concern here. Some decline is thought to have occurred but the current breeding population appears to be stable and widespread. In light of these facts, this study investigated various aspects of Song Thrush ecology in relation to the Irish landscape from 2001-2003. The breeding season extended from mid March to late June, where mean clutch size was 4.1 and number of fledglings was 3.7. There were very few third broods. Daily nest survival rates were calculated for egg stage 0.9362, incubation stage 0.9505 and nestling stage 0.6909. Most nest failures were due to avian predation at both egg and chick stages. Most nests were located 1.3 -2.4m from the ground at trees, bushes or hedgerow. Clutch size was significantly higher on farmland than garden & parkland and woodland, and the number of fledglings was significantly lower in nests in trees than hedgerow and bush sites. Daily nest fail rates were significantly higher at tree sites and partly concealed nests. Nesting areas had significantly denser vertical vegetation than non-nesting areas. Mercury and the organochlorine HEOD were the most common contaminants in Song Thrush eggs and livers. However concentrations and occurrence were low and of no apparent biological or ecological concern. The presence of breeding Song Thrushes was influenced by mixed surrounding farmland, the absence of grass surrounding farmland, ditches especially wet ones, tall dense vegetation and trimmed boundaries. Song Thrush winter densities were predicted by ditches, with wet or dry, low thin vegetation and untrimmed boundaries. Winter densities were almost double that of the breeding season, probably due to the arrival and passage of migrating Song Thrushes through the country, especially in November. Changes in Irish agriculture did not differ significantly in areas of Song Thrush breeding population stability and apparent decline during 1970 1990. Even though the current breeding population heavily uses farmland, woodland, human and scrub habitats are more preferred. Nevertheless no farmland habitat was avoided, highlighting a positive relationship between breeding Song Thrushes and Irish agriculture. This appears to be in contrast with findings between breeding Song Thrushes and British agriculture. Theses findings are compared with other studies and possible influences by agricultural intensification, climate, latitude and insular syndrome are discussed. Implications for conservation measures are considered, especially for areas of decline. Even though Song Thrushes are currently widespread and stable here, future environmental consequences of longer-term changes in Irish agriculture and perhaps climate change remain to be seen.
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The case for energy policy modelling is strong in Ireland, where stringent EU climate targets are projected to be overshot by 2015. Policy targets aiming to deliver greenhouse gas and renewable energy targets have been made, but it is unclear what savings are to be achieved and from which sectors. Concurrently, the growth of personal mobility has caused an astonishing increase in CO2 emissions from private cars in Ireland, a 37% rise between 2000 and 2008, and while there have been improvements in the efficiency of car technology, there was no decrease in the energy intensity of the car fleet in the same period. This thesis increases the capacity for evidenced-based policymaking in Ireland by developing techno-economic transport energy models and using them to analyse historical trends and to project possible future scenarios. A central focus of this thesis is to understand the effect of the car fleet‘s evolving technical characteristics on energy demand. A car stock model is developed to analyse this question from three angles: Firstly, analysis of car registration and activity data between 2000 and 2008 examines the trends which brought about the surge in energy demand. Secondly, the car stock is modelled into the future and is used to populate a baseline “no new policy” scenario, looking at the impact of recent (2008-2011) policy and purchasing developments on projected energy demand and emissions. Thirdly, a range of technology efficiency, fuel switching and behavioural scenarios are developed up to 2025 in order to indicate the emissions abatement and renewable energy penetration potential from alternative policy packages. In particular, an ambitious car fleet electrification target for Ireland is examined. The car stock model‘s functionality is extended by linking it with other models: LEAP-Ireland, a bottom-up energy demand model for all energy sectors in the country; Irish TIMES, a linear optimisation energy system model; and COPERT, a pollution model. The methodology is also adapted to analyse trends in freight energy demand in a similar way. Finally, this thesis addresses the gap in the representation of travel behaviour in linear energy systems models. A novel methodology is developed and case studies for Ireland and California are presented using the TIMES model. Transport Energy
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While numerous studies find that deep-saline sandstone aquifers in the United States could store many decades worth of the nation's current annual CO 2 emissions, the likely cost of this storage (i.e. the cost of storage only and not capture and transport costs) has been harder to constrain. We use publicly available data of key reservoir properties to produce geo-referenced rasters of estimated storage capacity and cost for regions within 15 deep-saline sandstone aquifers in the United States. The rasters reveal the reservoir quality of these aquifers to be so variable that the cost estimates for storage span three orders of magnitude and average>$100/tonne CO 2. However, when the cost and corresponding capacity estimates in the rasters are assembled into a marginal abatement cost curve (MACC), we find that ~75% of the estimated storage capacity could be available for<$2/tonne. Furthermore, ~80% of the total estimated storage capacity in the rasters is concentrated within just two of the aquifers-the Frio Formation along the Texas Gulf Coast, and the Mt. Simon Formation in the Michigan Basin, which together make up only ~20% of the areas analyzed. While our assessment is not comprehensive, the results suggest there should be an abundance of low-cost storage for CO 2 in deep-saline aquifers, but a majority of this storage is likely to be concentrated within specific regions of a smaller number of these aquifers. © 2011 Elsevier B.V.
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It is widely accepted that volumetric contraction and solidification during the polymerization process of restorative composites in combination with bonding to the hard tissue result in stress transfer and inward deformation of the cavity walls of the restored tooth. Deformation of the walls decreases the size of the cavity during the filling process. This fact has a profound influence on the assumption-raised and discussed in this paper-that an incremental filling technique reduces the stress effect of composite shrinkage on the tooth. Developing stress fields for different incremental filling techniques are simulated in a numerical analysis. The analysis shows that, in a restoration with a well-established bond to the tooth-as is generally desired-incremental filling techniques increase the deformation of the restored tooth. The increase is caused by the incremental deformation of the preparation, which effectively decreases the total amount of composite needed to fill the cavity. This leads to a higher-stressed tooth-composite structure. The study also shows that the assessment of intercuspal distance measurements as well as simplifications based on generalization of the shrinkage stress state cannot be sufficient to characterize the effect of polymerization shrinkage in a tooth-restoration complex. Incremental filling methods may need to be retained for reasons such as densification, adaptation, thoroughness of cure, and bond formation. However, it is very difficult to prove that incrementalization needs to be retained because of the abatement of shrinkage effects.
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The efficient remediation of heavy metal-bearing sediment has been one of top priorities of ecosystem protection. Cement-based solidification/stabilization (s/s) is an option for reducing the mobility of heavy metals in the sediment and the subsequent hazard for human beings and animals. This work uses sodium carbonate as an internal carbon source of accelerated carbonation and gaseous CO2 as an external carbon source to overcome deleterious effects of heavy metals on strength development and improve the effectiveness of s/s of heavy metal-bearing sediment. In addition to the compressive strength and porosity measurements, leaching tests followed the Chinese solid waste extraction procedure for leaching toxicity - sulfuric acid and nitric acid method (HJ/T299-2007), German leaching procedure (DIN38414-S4) and US toxicity characteristic leaching procedures (TCLP) have been conducted. The experimental results indicated that the solidified sediment by accelerated carbonation was capable of reaching all performance criteria for the disposal at a Portland cement dosage of 10 wt.% and a solid/water ratio of 1: 1. The concentrations of mercury and other heavy metals in the leachates were below 0.10 mg/L and 5 mg/L, respectively, complying with Chinese regulatory level (GB5085-2007). Compared to the hydration, accelerated carbonation improved the compressive strength of the solidified sediment by more than 100% and reduced leaching concentrations of heavy metals significantly. It is considered that accelerated carbonation technology with a combination of Na2CO3 and CO2 may practically apply to cement-based s/s of heavy metal-bearing sediment. (C) 2008 Elsevier B.V. All rights reserved.
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Anthropogenic eutrophication affects the Mediterranean, Black, North and Baltic Seas to various extents. Responses to nutrient loading and methods of monitoring relevant indicators vary regionally, hindering interpretation of ecosystem state changes and preventing a straightforward pan-European assessment of eutrophication symptoms. Here we summarize responses to nutrient enrichment in Europe's seas, comparing existing time-series of selected pelagic (phytoplankton biomass and community composition, turbidity, N:P ratio) and benthic (macro flora and faunal communities, bottom oxygen condition) indicators based on their effectiveness in assessing eutrophication effects. Our results suggest that the Black Sea and Northern Adriatic appear to be recovering from eutrophication due to economic reorganization in the Black Sea catchment and nutrient abatement measures in the case of the Northern Adriatic. The Baltic is most strongly impacted by eutrophication due to its limited exchange and the prevalence of nutrient recycling. Eutrophication in the North Sea is primarily a coastal problem, but may be exacerbated by climatic changes. Indicator interpretation is strongly dependent on sea-specific knowledge of ecosystem characteristics, and no single indicator can be employed to adequately compare eutrophication state between European seas. Communicating eutrophication-related information to policy-makers could be facilitated through the use of consistent indicator selection and monitoring methodologies across European seas. This work is discussed in the context of the European Commission's recently published Marine Strategy Directive.
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Protonated betaine bis(trifluoromethylsulfonyl) imide is an ionic liquid with the ability to dissolve large quantities of metal oxides. This metal-solubilizing power is selective. Soluble are oxides of the trivalent rare earths, uranium(VI) oxide, zinc(II) oxide, cadmium( II) oxide, mercury( II) oxide, nickel( II) oxide, copper(II) oxide, palladium(II) oxide, lead(II) oxide, manganese( II) oxide, and silver( I) oxide. Insoluble or very poorly soluble are iron(III), manganese(IV), and cobalt oxides, as well as aluminum oxide and silicon dioxide. The metals can be stripped from the ionic liquid by treatment of the ionic liquid with an acidic aqueous solution. After transfer of the metal ions to the aqueous phase, the ionic liquid can be recycled for reuse. Betainium bis( trifluoromethylsulfonyl) imide forms one phase with water at high temperatures, whereas phase separation occurs below 55.5 degrees C ( temperature switch behavior). The mixtures of the ionic liquid with water also show a pH-dependent phase behavior: two phases occur at low pH, whereas one phase is present under neutral or alkaline conditions. The structures, the energetics, and the charge distribution of the betaine cation and the bis( trifluoromethylsulfonyl) imide anion, as well as the cation-anion pairs, were studied by density functional theory calculations.