541 resultados para Charcoal
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We present the results of the microstratigraphic, phytolith and wood charcoal study of the remains of a 10.5 ka roof. The roof is part of a building excavated at Tell Qarassa (South Syria), assigned to the Pre-Pottery Neolithic B period (PPNB). The Pre-Pottery Neolithic (PPN) period in the Levant coincides with the emergence of farming. This fundamental change in subsistence strategy implied the shift from mobile to settled aggregated life, and from tents and huts to hard buildings. As settled life spread across the Levant, a generalised transition from round to square buildings occurred, that is a trademark of the PPNB period. The study of these buildings is fundamental for the understanding of the ever-stronger reciprocal socio-ecological relationship humans developed with the local environment since the introduction of sedentism and domestication. Descriptions of buildings in PPN archaeological contexts are usually restricted to the macroscopic observation of wooden elements (posts and beams) and mineral components (daub, plaster and stone elements). Reconstructions of microscopic and organic components are frequently based on ethnographic analogy. The direct study of macroscopic and microscopic, organic and mineral, building components performed at Tell Qarassa provides new insights on building conception, maintenance, use and destruction. These elements reflect new emerging paradigms in the relationship between Neolithic societies and the environment. A square building was possibly covered here with a radial roof, providing a glance into a topologic shift in the conception and understanding of volumes, from round-based to square-based geometries. Macroscopic and microscopic roof components indicate buildings were conceived for year-round residence rather than seasonal mobility. This implied performing maintenance and restoration of partially damaged buildings, as well as their adaptation to seasonal variability
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A study was conducted on the adsorption of Escherichia coli bacteriophage T4 to activated carbon. Preliminary adsorption experiments were also made with poliovirus Type III. The effectiveness of such adsorbents as diatomaceous earth, Ottawa sand, and coconut charcoal was also tested for virus adsorption.
The kinetics of adsorption were studied in an agitated solution containing virus and carbon. The mechanism of attachment and site characteristics were investigated by varying pH and ionic strength and using site-blocking reagents.
Plaque assay procedures were developed for bacteriophage T4 on Escherichia coli cells and poliovirus Type III on monkey kidney cells. Factors influencing the efficiency of plaque formation were investigated.
The kinetics of bacteriophage T4 adsorption to activated carbon can be described by a reversible second-order equation. The reaction order was first order with respect to both virus and carbon concentration. This kinetic representation, however, is probably incorrect at optimum adsorption conditions, which occurred at a pH of 7.0 and ionic strength of 0.08. At optimum conditions the adsorption rate was satisfactorily described by a diffusion-limited process. Interpretation of adsorption data by a development of the diffusion equation for Langmuir adsorption yielded a diffusion coefficient of 12 X 10-8 cm2/sec for bacteriophage T4. This diffusion coefficient is in excellent agreement with the accepted value of 8 X 10-8 cm2/sec. A diffusion-limited theory may also represent adsorption at conditions other than the maximal. A clear conclusion on the limiting process cannot be made.
Adsorption of bacteriophage T4 to activated carbon obeys the Langmuir isotherm and is thermodynamically reversible. Thus virus is not inactivated by adsorption. Adsorption is unimolecular with very inefficient use of the available carbon surface area. The virus is probably completely excluded from pores due to its size.
Adsorption is of a physical nature and independent of temperature. Attraction is due to electrostatic forces between the virus and carbon. Effects of pH and ionic strength indicated that carboxyl groups, amino groups, and the virus's tail fibers are involved in the attachment of virus to carbon. The active sites on activated carbon for adsorption of bacteriophage T4 are carboxyl groups. Adsorption can be completely blocked by esterifying these groups.
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Este trabalho visa determinar a contribuição das emissões evaporativas provenientes dos veículos leves de passageiro, para a degradação da qualidade do ar atmosférico. O objetivo principal é avaliar as concentrações compostos monoaromáticos voláteis Benzeno, Tolueno, Etilbenzeno e Xilenos (BTEX) em ambientes confinados, sendo este realizado em um local que caracterize a realidade da frota veicular da Região metropolitana do Rio de Janeiro. As amostras foram coletadas em um estacionamento subterrâneo de um Shopping Center da zona norte do Rio de Janeiro, através do sistema de amostragem ativa, utilizando cartucho de carvão ativo como adsorvente. As amostras foram extraídas com solvente orgânico e analisadas posteriormente por Cromatografia gasosa acoplada à espectrometria de massas (CGEM). As médias dos resultados obtidos foram 52,7 g.m-3 para o benzeno, 203,6 g.m-3 para o tolueno, 44,6 g.m-3 para o etilbenzeno, 115,7 g.m-3 para os xilenos, sendo o tolueno o composto encontrado em maior abundância. Esses resultados foram comparados com resultados encontrados na literatura de emissões veiculares em ambientes confinados como garagens e túneis. Foi investigada a correlação com as emissões do veículo em movimento, obtidas através de estudos previamente realizados em um túnel de grande circulação e as emissões obtidas no estacionamento subterrâneo. Através desses dados ficou demonstrada diferença das fontes de emissão.
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Muitos dos locais onde as atividades são realizadas nas academias de ginásticas são salas pequenas e fechadas com sistema de climatização artificial, freqüentados por um grande número de alunos realizando seus exercícios e profissionais auxiliando as atividades. Com isso, há uma intensa transpiração desses indivíduos, uma freqüente rotina de limpeza do piso e de equipamentos com pequenos intervalos, possibilitando a alterações da qualidade do ar indoor. O presente trabalho busca mostrar as tendências de variações nos valores das concentrações dos poluentes atmosféricos BTEX em ambiente indoor, especificamente na sala de spinning de uma academia de ginástica do Rio de Janeiro. Para o monitoramento da qualidade do ar foram utilizados cartuchos de carvão ativado SKC, acoplado a uma bomba KNF com vazão de 1l min. Para a extração de cada amostra foi feita a análise cromatográfica com cromatógrafo a gás modelo 6890 acoplado a um espectrômetro de massa modelo 5973 da marca Agilent. Foram analisadas 34 amostras coletadas na salas de spinning durante as aulas com atividades aeróbicas, o que intensificava a respiração dos indivíduos, possibilitando uma maior inalação destes COVs. Em contrapartida, também foram coletadas 5 amostras outdoor, 4 delas pareadas indoor/ outdoor para uma análise comparativa das concentrações destes poluentes. Dentre os compostos orgânicos voláteis analisados, o tolueno é o BTEX mais abundante obtido neste trabalho, representando 81% destes COVs indoor. Todas as amostras medidas em pares indoor/ outdoor tiveram concentrações maiores no interior, exceto para o benzeno no dia 3/12/2010. Simples atividades usualmente realizadas pelo homem, como a inserção de piso emborrachado, manutenção do sistema de climatização artificial, e limpeza podem alterar o ar indoor. As conclusões alcançadas após as medições das concentrações de BTEX foram de que o ar indoor estava mais poluído do que o outdoor. Este monitoramento da qualidade do ar indoor ainda é escasso no Brasil. Alguns esforços tem sido feito em relação a ambientes confinados como a Portaria n˚3523 do Ministério da Saúde, regulamentando o controle dos ambientes climatizados e a Resolução n˚9 da Agência Nacional de Vigilância Sanitária, além da Resolução CONAMA n ˚3 estabelecendo padrões de qualidade do ar para alguns compostos químicos, porém muitos compostos químicos ainda não são legislados ou não possuem a devida atenção, não sendo suficientes para contemplar a complexidade do assunto
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[ES] La introducción de técnicas físico-químicas al estudio del grafismo rupestre paleolítico está abriendo nuevos campos de conocimiento sobre los procedimientos técnicos, la cronología y la conservación de los motivos. La utilización de la técnica radiométrica de C14 A.M.S. ha sido aplicada en Covalanas. Las dataciones de época histórica de dos pequeños fragmentos de carbón procedentes de marcas negras sirven para reflexionar en torno al llamado «arte esquemático-abstracto».
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Homenaje a Ignacio Barandiarán Maestu / coord. por Javier Fernández Eraso, Juan Santos Yanguas
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O principal objetivo deste estudo é estimar o alcance dos poluentes emitidos pelo Aterro Controlado do Morro do Céu (ACMC), localizado em Niterói e as possíveis áreas afetadas. Utilizou-se um modelo matemático para o estudo do transporte e difusão dos poluentes que fornece a concentração nas vizinhanças, a partir dos dados de emissões, meteorológicos e topográficos. Foram analisados e tratados os dados meteorológicos e a topografia da região de alcance da pluma. As amostras foram coletadas por uma bomba de ar a uma vazão de 500 mL min-1 por um período de 10 min, em dois dias e horários diferentes. A câmara de fluxo empregada foi de 30 L e de PVC, no formato cilíndrico, cuja boca foi emborcada no solo por 5 cm e a amostragem realizada por uma válvula posicionada no fundo. Foram empregados como meios de amostragem cartuchos de carvão ativo de leito duplo e as análises químicas foram realizadas por cromatografia de fase gasosa com detecção por ionização na chama. Os resultados encontrados indicam que o ACMC pode conter quantidade significativa de vários compostos químicos, principalmente compostos orgânicos voláteis, impactando a vegetação, prejudicando a saúde e a qualidade de vida da população do seu entorno. Foram obtidos valores de compostos orgânicos voláteis acima de 400 g m-3 a menos que 500 m do ACMC. Considerando que o ACMC não será desativado em um tempo próximo, creches, escolas e postos de saúde devem ser deslocados para uma área onde o impacto dos poluentes atmosféricos seja menor, contribuindo para a melhoria da qualidade de vida da população
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The findings are presented of a study conducted in Calauag Bay, Quezon Province, Philippines in order to estimate resource rent of mangrove areas converted to fishpond production. The rents were calculated based on the technology practised by the farmers and the prices of inputs and outputs that prevailed during the study period. The major causes of mangrove depletion are cutting of mangroves for fuelwood and charcoal and clearing for fishpond development. It was concluded that there is justification for the government to increase the feed which could be used to rehabilitate the inland-coastal fisheries to improve productivity and ensure sustainability of the ecosystem for future generations.
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本研究以河北围场县广发永化石点早中新世地层中的球果和果实、浙江宁海县杜岙化石点早上新世地层中的半矿化化石木、云南寻甸县金所和先锋化石点晚上新世地层中的丝炭和褐煤化木材为研究对象,对这三个化石点数百个植物大化石的形态或解剖结构进行了详细研究,鉴定出6个新的化石种,4个新记录种,7个未定种;其中2个化石属为我国新记录。根据其结构特征探讨这些化石类群与相关化石和现代植物的系统关系。并依据其现代亲缘种生长的生态和气候范围,对化石点沉积时期的植被和气候类型进行了推测。 果实中含有多种有价值的分类和系统发育的信息,对于种子植物的演化和系统发育研究具有重要的意义。在河北围场县发现大量保存较好的松科球果和姜科化石,为我们进一步研究松科植物和姜科植物解剖结构,以及探讨其系统演化提供难得的机会和直接的证据,同时为该化石地的植被演替和地层对比研究提供更多的植物学证据。对河北围场县广发永化石点球果和果实的形态研究,鉴定出三种松科球果化石种和一种姜科植物。分别为围场松(Pinus weichangensis sp. nov.)、围场云杉(Picea weichangensis sp. nov.)、围场铁杉(Tsuga weichangensis sp. nov.)以及化石Spirematospermum属未定种。其中围场云杉、围场铁杉球果在形态上与相应现代类群具有明显的差异,可能代表已灭绝的种类。Spirematospermum属未定种为一绝灭类型,是该属在我国的首次记录。这四种化石类群发现,反映早中新世化石该化石点气候与现代完全不同,为湿润的暖温带和亚热带气候。 浙江省在地质结构上位于东亚大陆边缘,是环太平洋岩浆活动带的重要组成部分。宁海县属于浙东南区属华南地层区,其第三纪地层嵊县群在该区分布广泛,其古植物研究仅限于孢粉和叶化石。本报告中首次对该层铜岭祝组的木化石进行了报道。对浙江宁海杜岙化石点早上新世地层中化石木样品的解剖研究,鉴定出三种木材类型,为史马库栎型木Quercus shimakurae、Liqumdambar cf. hisauchi和蔷薇科未定种。前者与现代栎属槲栎类、后者与枫香树属分别具有密切的亲缘关系,是我国首次报道栎属和枫香树属化石木。 云南现今复杂的地势地貌,独特的气候,丰富的植物种类和多样的植被类型是经历了长达数百万年的地质构造运动和自然环境演变的结果。第三纪时期由于大陆板块运动导致印度板块与亚洲板块的对接和碰撞,其地壳构造运动异常活跃。其第三系陆相地层广泛分布于古生代褶皱区的200多个互不相连的中、小型盆地及中、新生代断陷和拗陷型山间盆地中,并蕴涵了丰富的植物化石,为我们研究植被和植物演化提供了众多的证据。本次研究基于云南中部寻甸县金所煤矿和先锋煤矿的大量褐煤化和丝炭化材料,为进一步恢复云南晚第三纪气候和植被提供更多的依据,尤其是丝炭材料保存了木材精细而真实的结构,为木材准确鉴定和演化提供了可靠的依据。根据对云南金所和先锋化石点晚上新世沉积中褐煤化材料和丝炭样品解剖结构的研究,鉴定出8种化石木,包括2种裸子植物,5种双子叶植物和1种单子叶植物;分属5科7属。化石类群包括松属(Pinus)五针松组未定种Section Cembra sp.、云杉属未定种Picea sp、寻甸含笑Michelia xundianensis sp. nov.、多角含笑 Michelia angulata sp. nov.、Lithocarpoxylon cf. radiporosum、Castanoradix sp.、寻甸珍珠花Lyonia xundianensis sp. nov.、竹亚科未定种Bambusoideae sp。根据现今这些化石对应类群的生长和分布的气候区域,沉积时期的气候与现代气候较为接近。
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EXTRACT (SEE PDF FOR FULL ABSTRACT): Though knowledge of fire occurrence and weather pattern relationships has been used for many years by land managers in, for instance, prescribed fire planning, understanding of the relationship between Holocene climates and fire is just beginning to be investigated. We are investigating this relationship in a major mountain range in California, examining charcoal and pollen content in sediments of montane meadows to compare paleo-fire and paleo-vegetation (thus, climate) sequences for the Holocene.
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黑碳(BC)是生物质和化石燃料不完全燃烧产生的高度聚合的碳质混合物,包括木炭 (char/charcoal)和烟炱碳(soot)等形式。黑碳产生后大部分储存在燃烧原地,而烟炱碳 由于粒径较小,易进入大气,滞留一到数周后回到地表。部分土壤黑碳随河流和大气的搬 运作用进入海洋环境,主要汇集在海岸带沉积物中。由于黑碳涉及到气候变化、碳循环、 环境危害、人体健康等诸多问题而成为当前气候与环境领域的研究热点。黑碳在环境介质 中比较稳定,因而可以较好的指示人类能源使用及其对环境质量的影响;同时黑碳具有很 强的吸附性,能显著影响周围介质中持久性有机污染物(如多环芳烃等)的赋存状态和生态 毒理效应。 多环芳烃(PAHs)是指两个或两个以上的苯环以稠环形式结合的芳香族化合物,主要 来源于含碳物质的不完全燃烧过程,在环境中广泛存在。由于PAHs 具有潜在的致癌性、 致畸性和致突变性(“三致”效应)而在环境研究领域中备受关注。另外由于具有主体的 同源性,PAHs 可以指示BC 的来源和环境过程。 海岸带沉积物是包括BC 和PAHs 在内的众多污染物在环境地球化学迁移过程中的主 要载体和归宿,由于受到陆地和海洋双重作用,海岸带对环境污染物尤其敏感。环渤海地 区是我国北方的社会经济中心,工业、农业和交通发达、人口稠密,污染严重。前人的研 究表明渤海湾的BC 和PAHs 污染程度明显高于我国其他海岸带,但受限制于采样区域和 样品数量,不能全面地反应BC 和PAHs 在渤海湾海岸带的分布状况及人类活动对海岸带 环境质量的影响。 本次研究在渤海湾海岸带潮间带、近海及主要入海河流系统布设了多条采样剖面,采 集表层沉积物样品85 个。首先,对国际上较为常用的化学热氧化法(CTO-375)处理沉积 物黑碳样品的方法进行了比对实验和优化,然后对全部样品进行黑碳分析;利用GC-MS 方法对样品中的PAHs(USEPA 的16 种优控物)进行了定量检测;对全部沉积物样品还进 行了粒度分析。 结果表明,该区域内黑碳的含量为0.09 到22.8 mg/g dw,其中,潮间带样品的BC 平 均含量为0.52 ± 0.39 mg/g dw,近海样品为0.84 ± 0.38 mg/g dw,河流样品(海河样品除外) 为1.88 ± 0.89 mg/g dw。BC占总有机碳的比例在潮间带、近海、河流区域分别为18.4 ± 8.3%、 14.5 ± 5.3%、14.2 ± 4.1%。潮间带黑碳存在明显的“北高南低”的趋势(以天津港码头和 海河为界),与近海和河流样品的BC 浓度有相似的变化趋势,反映了BC 在海岸带的运移 扩散具有一定的继承性;河流输入可能是近岸沉积物BC 的主要来源。同时,潮间带沉积 物粒度分析结果表明“北区细”(以粘土质粉砂主)而“南区粗”(以砂为主),反映了两个区 域不同的水动力条件和沉积环境,可能是造成BC 浓度空间分异的主要原因。 摘要 II 多环芳烃的含量分布为33.1-7658.7 ng/g dw,其中,潮间带样品的PAHs 平均含量为 147.0 ng/g dw,近海样品为170.9 ng/g dw,河流样品(海河样品除外)为1228.5 ng/g dw。 主要成分均为三环和四环多环芳烃。PAHs 也呈现出了与BC 相似的“北高南低”的趋势, 多环芳烃与黑碳的相关性研究表明两者相关性较好(R2=0.59),表明多环芳烃和黑碳的同 源性和继承性。运用比值法(菲/蒽,荧蒽/芘,低环/高环等)对多环芳烃的来源解析显示, 整个研究区域内多环芳烃主要为燃烧源。
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Fishing communities that have exploited the resource for generations constitute the main stakeholder groups in the fisheries of Lake Victoria. Several studies have examined Uganda's Lake Victoria fishing communities and characterised key stakeholders at community level over the last decade (SEDAWOG 1999a and b; Geheb 1997; FeSEP 1997; Kitakule 1991). The communities are made up of scattered settlements at the shores and on islands. The categories of people living in these communities include fishers who consist primarily of large numbers of male youths who provide labour to boat and gear owners. There are resident and non-resident fish traders who after securing their supplies at the beaches, depart for their market destinations. In addition, there are fish processors, mostly operating traditional and improved smoking kilns. Many other people, dealing in provisions and supplies also stay at the beaches, their activities depending on the level of fish catch. The fishing communities of Lake Victoria, Uganda, include auxiliary livelihood activities such as boat building, net repairing and transportation; bait supply and beachside kiosks, video halls and retail shop business. Other economic activities are brick making, charcoal burning/wood trade, farming and livestock keeping.
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The ring hydrogenation of benzoic acid to cyclohexanecarboxylic acid over charcoal-supported transition metal catalysts in supercritical CO2 medium has been studied in the present work. The cyclohexanecarboxylic acid can be produced efficiently in supercritical CO2 at the low reaction temperature of 323 K. The presence of CO2 increases the reaction rate and several parameters have been discussed.
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Novel poly(ester carbonate)s were synthesized by the ring-opening polymerization Of L-lactide and functionalized carbonate monomer 9-phenyl-2,4,8,10-tetraoxaspiro[5,5]undecan-3-one derived from pentaerythritol with diethyl zinc as an initiator. H-1 NMR analysis revealed that the carbonate content in the copolymer was almost equal to that in the feed. DSC results indicated that T-g of the copolymer increased with increasing carbonate content in the copolymer. Moreover, the protecting benzylidene groups in the copolymer poly(L-lactide-co-9-phenyl-2,4,8,10-tetraoxaspiro[5,5]undecan-3-one) were removed by hydrogenation with palladium hydroxide on activated charcoal as a catalyst to give a functional copolymer, poly(L-lactide-co-2,2-dihydroxylmethyl-propylene carbonate), containing pendant primary hydroxyl groups. Complete deprotection was confirmed by H-1 NMR and FTIR spectroscopy. The in vitro degradation rate of the deprotected copolymers was faster than that of the protected copolymers in the presence of proteinase K. The cell morphology and viability on a copolymer film evaluated with ECV-304 cells showed that poly(ester carbonate)s derived from pentaerythritol are good biocompatible materials suitable for biomedical applications.