Bibliografías temáticas / Element trace metals

Índice

Artículos de revistas
Tesis
Libros
Capítulos de libros
Actas de conferencias
Informes

Literatura académica sobre el tema "Element trace metals"

Autor: Grafiati

Publicado: 4 de junio de 2021

Última modificación: 1 de febrero de 2022

Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros

Elija tipo de fuente:

Consulte las listas temáticas de artículos, libros, tesis, actas de conferencias y otras fuentes académicas sobre el tema "Element trace metals".

Junto a cada fuente en la lista de referencias hay un botón "Agregar a la bibliografía". Pulsa este botón, y generaremos automáticamente la referencia bibliográfica para la obra elegida en el estilo de cita que necesites: APA, MLA, Harvard, Vancouver, Chicago, etc.

También puede descargar el texto completo de la publicación académica en formato pdf y leer en línea su resumen siempre que esté disponible en los metadatos.

Artículos de revistas sobre el tema "Element trace metals"

Zhang, Yan y Vadim N. Gladyshev. "Comparative Genomics of Trace Element Dependence in Biology". Journal of Biological Chemistry 286, n.º 27 (12 de mayo de 2011): 23623–29. http://dx.doi.org/10.1074/jbc.r110.172833.

Texto completo

Resumen

Biological trace elements are needed in small quantities but are used by all living organisms. A growing list of trace element-dependent proteins and trace element utilization pathways highlights the importance of these elements for life. In this minireview, we focus on recent advances in comparative genomics of trace elements and explore the evolutionary dynamics of the dependence of user proteins on these elements. Many zinc protein families evolved representatives that lack this metal, whereas selenocysteine in proteins is dynamically exchanged with cysteine. Several other elements, such as molybdenum and nickel, have a limited number of user protein families, but they are strictly dependent on these metals. Comparative genomics of trace elements provides a foundation for investigating the fundamental properties, functions, and evolutionary dynamics of trace element dependence in biology.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Liu, Xiao Ling, Jian Wang, Yong Hui Song y Ping Zeng. "Response Surface Optimization of Trace Element Requirement for the Production of Volatile Fatty Acids from Excess Sludge". Advanced Materials Research 878 (enero de 2014): 663–69. http://dx.doi.org/10.4028/www.scientific.net/amr.878.663.

Texto completo

Resumen

Anaerobic microorganisms involved in VFAs fermentation have inherent requirements for trace metals. It is inferred that excess sludge contains inadequate amounts of bioavailable trace metals for high-rate VFAs fermentation. The unavailability of these trace metals is probably the primary reason of poor yield without any other obvious reason. However, trace metal requirements in VFAs fermentation are not often reported in literature. Therefore, minimum requirements for trace metals including Zn, Co, Cu, Fe and Mn in VFAs fermentation from excess sludge were investigated. Firstly, the effect of each trace metal element on the VFAs production was investigated, respectively. And then, response surface methology was employed to optimize the requirement conditions of these five trace elements. The results showed that these five metal elements had the potential to enhance the production of VFAs, and the improved influences were as follows: Fe > Co > Mn > Cu > Zn. However, the production of VFAs decreased obviously with a further increase of each trace element. The optimal mixed conditions of these five trace elements were found to be 0.0982% Fe, 0.0047% Co, 0.0053% Zn, 0.0038% Cu and 0.0936% Mn. Under the optimal conditions, the concentration of VFAs reached 8410 mg/L, and increased by 2.5 times compare with the control. Finally, the consistent results between the prediction and the experiment indicated that the established polynomial model was feasible, and VFAs production could be described well by this model.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Semenov, M. Yu, V. A. Snytko, Yu M. Semenov, A. V. Silaev y L. N. Semenova. "Metals composition of the surface waters of the Southern Baikal region and its connection with landscape and geological conditions". Доклады Академии наук 486, n.º 5 (20 de junio de 2019): 613–19. http://dx.doi.org/10.31857/s0869-56524865613-619.

Texto completo

Resumen

The metal composition of water and bottom sediments of southern Lake Baikal tributaries was studied and the water migration coefficients for micro- and trace elements were calculated. The map showing the study area divided into zones according to their ability to provide the certain water quality was drawn. The significant differences in mineralization, macro- and trace element composition between Lake Baikal water and tributary waters were found out. It was shown that values of water migration coefficients calculated for macro elements are similar in southern and main tributaries whereas coefficient values calculated for trace elements are quite different. This is due to dissolved matter sources such as rocks and deep ground waters which chemical composition is not typical for landscapes of Lake Baikal basin. The contribution of southern tributaries to macro element composition of lake water is between 7 and 15%, whereas tributaries contribution to trace element composition can hardly be evaluated because of higher element concentrations in riverine waters. The lower trace element concentrations in lake water with respect to riverine one is due to trace element migration in the form of complex organic compounds: long water residence time in lake favors to organic compounds decay by means of microbial- and photo-degradation followed by metal precipitation.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Cleave y Crans. "The First-Row Transition Metals in the Periodic Table of Medicine". Inorganics 7, n.º 9 (6 de septiembre de 2019): 111. http://dx.doi.org/10.3390/inorganics7090111.

Texto completo

Resumen

In this manuscript, we describe medical applications of each first-row transition metal including nutritional, pharmaceutical, and diagnostic applications. The 10 first-row transition metals in particular are found to have many applications since there five essential elements among them. We summarize the aqueous chemistry of each element to illustrate that these fundamental properties are linked to medical applications and will dictate some of nature’s solutions to the needs of cells. The five essential trace elements—iron, copper, zinc, manganese, and cobalt—represent four redox active elements and one redox inactive element. Since electron transfer is a critical process that must happen for life, it is therefore not surprising that four of the essential trace elements are involved in such processes, whereas the one non-redox active element is found to have important roles as a secondary messenger.. Perhaps surprising is the fact that scandium, titanium, vanadium, chromium, and nickel have many applications, covering the entire range of benefits including controlling pathogen growth, pharmaceutical and diagnostic applications, including benefits such as nutritional additives and hardware production of key medical devices. Some patterns emerge in the summary of biological function andmedical roles that can be attributed to small differences in the first-row transition metals.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Doherty, G. B., D. Coomans y G. J. Brunskill. "Modelling natural and enhanced trace metal concentrations in sediments of Cleveland Bay, Australia". Marine and Freshwater Research 51, n.º 8 (2000): 739. http://dx.doi.org/10.1071/mf98141.

Texto completo

Resumen

The major element and trace metal analytical results of a strong acid digestion have been used to model natural and enhanced trace metal concentrations in surface sediment samples from Cleveland Bay. The natural ranges in concentration of cadmium, cobalt, copper, nickel, lead and zinc in sediments have been modelled by multiple linear regression using major elements as independent variables. Sites that exceed the upper 95% prediction interval of the regression model of the natural range in concentration are classified as enhanced. Enhancement of sites by metals derived from anthropogenic sources is characterized by enhancement of cadmium, copper, lead or zinc, and can be identified by Principle Components Analysis. Sites that contain metals derived from anthropogenic sources occur within the intertidal and near-shore sediments of western Cleveland Bay. No evidence of trace metals derived from anthropogenic sources was found within the sediments of the central bay.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Dobrinas, Simona, Alina Soceanu, Gabriela Stanciu, Viorica Popescu y Luiza Georgiana Arnold. "Trace element levels of three mushroom species". Analele Universitatii "Ovidius" Constanta - Seria Chimie 24, n.º 1 (1 de junio de 2013): 39–42. http://dx.doi.org/10.2478/auoc-2013-0008.

Texto completo

Resumen

AbstractThe aim of this study was to determine Cu, Fe and Cr contents of three species of fresh mushrooms and canned mushrooms: white and brown champignon (Agaricus bisporus) and Pleurotus Ostreatus. Were analyzed various plant parts: stem, cap and cuticle of fresh mushrooms and only stem and cap for canned mushrooms. The levels of trace metals of mushroom samples collected from regions of Romania, Poland and Turkey were determined by UV/Visible spectrometry - standard addition method after digestion method. The contents of investigated trace metals in mushroom samples were found to be in the range of 0.01 - 2.26 mg/Kg for chromium, 2.02 - 430.67 mg/Kg for copper and 240.40 - 7952.89 mg/Kg for iron. The iron content was found to be higher than those of the other two minerals in all the samples. Mushrooms species in the highest levels of trace elements were found white champignon for Cu and Fe and brown champignon for Cr.

Los estilos APA, Harvard, Vancouver, ISO, etc.

ORTEGA, RICHARD. "MICRO-PIXE FOR SINGLE CELL ANALYSIS". International Journal of PIXE 22, n.º 01n02 (enero de 2012): 51–56. http://dx.doi.org/10.1142/s0129083512400220.

Texto completo

Resumen

The knowledge of the intracellular distribution of biological relevant metals is important to understand their mechanisms of action in cells, either for physiological, toxicological or pathological processes. However, the direct detection of trace metals in single cells is a challenging task that requires sophisticated analytical developments. The combination of micro-PIXE with RBS and STIM (Scanning Transmission Ion Microscopy) allows the quantitative determination of trace metal content within sub-cellular compartments. The application of STIM analysis provides high spatial resolution imaging (< 200 nm) and excellent mass sensitivity (< 0.1 ng). Application of the STIM-PIXE-RBS methodology is absolutely needed when organic mass loss appears during PIXE-RBS irradiation. This combination of STIM-PIXE-RBS provides fully quantitative determination of trace element content, expressed in μg/g, which is a quite unique capability for micro-PIXE compared to other micro-analytical methods such as the electron and synchrotron x-ray fluorescence. Examples of micro-PIXE studies for sub-cellular imaging of trace elements in various fields of interest will be presented: in patho-physiology of trace elements involved in neurodegenerative diseases such as Parkinson's disease, and in toxicology of metals such as cobalt.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Budko, D. F. y D. M. Martynova. "Trace element uptake assessment in the planktonic biofiltration system". Океанология 59, n.º 1 (18 de abril de 2019): 33–44. http://dx.doi.org/10.31857/s0030-157459133-44.

Texto completo

Resumen

The concentration of trace elements (Fe, Mn, Cr, Co, Ni, Cu, Pb, Cd, As) through the planktonic food chain of the White Sea have been studied by the experimental approach. The experiment included zooplankton sampled in a reference area feeding on a seston contained the different trace metals concentrations. Seston sampled in the st. Chupa was enriched by Fe, Cu, Pb, Cr, Co, As, and Ni comparing to the seston from st. Kartesh (reference area). The differences in the concentrations of the suspended particular matter and of the indicator elements of a terrigenous admixture (Al, Ti, Zr) evidence on higher natural background of the trace metals’ content in the seston from st. Chupa due to higher contribution of the minerals. Zooplankton that fed on the seston characterised by higher trace elements’ content has accumulated Fe, Mn, and Cr, at a less degree, Ni, Co, Pb, and Cu; particularly, these were the elements which content were high in seston. Despite Mn content in seston did not differ between two treatments, this element was accumulated by the zooplankton, but had low content in faecal pellets. This tells about the highest Mn assimilation by the zooplankton; this element may become the most bioavailability. When comparing the trace element content between the seston and the faecal pellets, the concentrations of the most elements in faecal pellets are lower comprising as low as Zn – 72%; Mn – 24; Cu – 97; Pb – 62; Cr – 99; Co – 78; Ni – 87; As – 96; Cd – 65% of the concentration in the seston.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Zhang, Qing Wei, She Li Chai, Jing Cai y Li Na Gao. "Baseline Concentrations of Trace Metals in Grassland Topsoils from West Jilin Province, Northeast China". Advanced Materials Research 347-353 (octubre de 2011): 2140–45. http://dx.doi.org/10.4028/www.scientific.net/amr.347-353.2140.

Texto completo

Resumen

The objective of this study was to determine the baseline concentrations of trace elements in grassland topsoils from 155 soil sampling sites in West Jilin province, Northeast China, to establish the relationships between the trace metal contents and soil physicochemical properties and major oxide contents and among trace metal concentrations themselves, and to identify the possible sources of trace element in soils. The baseline concentrations of trace elements(mg/kg) were: As 3.12-14.18, B 16.17-49.08, Cd 0.037-0.127, Co 0.96-15.28, Cr 18.87-60.83, Cu 10.81-24.75, Hg 0.004-0.035, Mn 171.25-657.87, Mo 0.08-1.15, Ni 6.79-30, Pb 12.58 -26.08, Se 0.03-0.36, and Zn 18.93-61.03. The upper baseline limits of these elements were all less than the Chinese Environmental Quality Standard for Soils, the Dutch Intervention Values for Soils, implying that trace element contents in the studied soils were of the safety levels.Fe2O3 and Al2O3 had stronger correlations with most trace elements than other oxides, and Co,Cr,Cu,Mn, Ni were highly correlated one another. Three types of geochemical associations were distinguished from this study:the first association involving As,Co,Cr,Cu,Mn,Mo,Ni,Pb,Zn,Al2O3 and Fe2O3 was mainly associated with Al,Fe-Mn oxides and/or with the Al-bearing clay minerals, suggesting that the trace elements were mainly derived from lithogenic and pedogenic processes; the second association including Se, Hg, Cd, CaO and organic carbon was mainly associated with organic matter and calcium oxides, showing that Se,Hg and Cd were mainly contributed by anthropogenic sources; the third association containing B, Na2O, K2O, MgO, pH, and electrical conductivity was mainly associated salinization processes of soils, implying that alkaline pH and high Na contents would enhance B concentration of soils.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Stafilov, Trajče y Irina Karadjova. "Atomic absorption spectrometry in wine analysis". Macedonian Journal of Chemistry and Chemical Engineering 28, n.º 1 (15 de junio de 2009): 17. http://dx.doi.org/10.20450/mjcce.2009.218.

Texto completo

Resumen

This article reviews methods for the determination and identification of trace elements in wine by using atomic absorption spectrometry (AAS). Wine is one of the most widely consumed beverages and strict analytical control of trace elements content is required during the whole process of wine production from grape to the final product. Levels of trace elements in wine are important from both points of view: organoleptic – Fe, Cu, Mn and Zn concentrations are directly related to the destabilization and oxidative evolution of wines, and toxicological – toxic elements content should be under the allowable limit, wine identification. The identification of metals in wine is subject of increasing interest since complexation may reduce their toxicity and bioavailability. AAS is one of widely used methods for routine analytical control of wine quality recommended by the International Organization of Vine and Wine. Two main approaches – preliminary sample digestion and direct instrumental measurement combined with AAS for trace element determination in wines are reviewed and discussed. Procedures for various sample pretreatments, for trace element separation and preconcentration are presented. Advances in metal identification studies in wines based on AAS are presented.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Más fuentes

Tesis sobre el tema "Element trace metals"

Voigt, Astrid. "Bioavailability of trace metals to plants". Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=19561.

Texto completo

Resumen

Soil quality guidelines are currently based on total trace metal loads. There is a need to define indices of bioavailability to allow reasonable predictions for plant metal uptake and toxicity in soils. Trace metal toxicities to plants often correlate best with free metal ion activities. The first objective was to develop a plant bioassay that is sensitive to trace metals at concentrations realistic for soils. The root elongation of lettuce Lactuca sativa 'Buttercrunch' was used as toxicological endpoint. This endpoint was sensitive and reproducible to environmentally relevant concentrations of Cd, Cu, Ni, Pb and Zn. The second objective was to test whether free metal ion activities are constant predictors of metal toxicities in synthetic solutions and in soil extracts that differ in their concentrations of cations and ligands. The root elongation assay was used to test this hypothesis. In synthetic solutions, the rhizotoxicity of Cd, Cu, Ni, Pb and Zn decreased with increasing Ca and H concentrations. This could not be explained with the effect of higher cationic concentrations on root growth or on solution speciation. It was concluded that Ca and H inhibited the rhizotoxicity of all metals tested. The rhizotoxicity of Cu and Cd was further examined in soil extracts. Both metals became less rhizotoxic at higher H and dissolved organic matter concentrations. The rhizotoxicity endpoints from the experiments in synthetic solution were used to develop parameters for a Biotic Ligand Model (BLM) for Cd, Cu, Ni, Pb and Zn. The BLM accounts for solution speciation and interprets cationic inhibition of rhizotoxicity as competition of metals with Ca and H for potential sites of rhizotoxicity. The BLM predicted metal rhizotoxicity better than the free metal ion activity in synthetic solutions and in soil extracts. Different models were tested against literature rhizotoxicity data for metals at different Ca and H concentrations. Predictions for metal rhizotoxicity given by BLM, Gouy-Chapman-Stern model and Freundlich equation model were compared with predictions based on free metal ion activities in solution. The BLM predicted rhizotoxicity most accurately. The BLM seems promising for predictions of metal toxicity and metal bioavailability in soils to support site-specific environmental risk assessments.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Reyes, Delgadillo Dulce B. "Modeling natural attenuation of trace elements in soils". Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=101169.

Texto completo

Resumen

Trace elements added to the soil by human activities could contaminate it and occasionally cause a threat to environmental and human health. The toxicity and mobility of a trace element are affected by the element's solubility, which in turn is influenced by the soil properties. When mobile, trace elements can be leached out of the soil. If leaching occurs at a faster rate than atmospheric deposition, element concentrations in the soil will decrease by natural attenuation.
We analyzed soil properties in 40 soils and their soil solutions to obtain a set of equations with the most significant predictors of As, Cd, Co, Cu, Mo, Ni, Pb and Zn in solution. The total element concentration and the pH were the best predicting variables of the amount of element in solution for all trace elements analyzed, while organic carbon and Al or Mn oxides also influenced the solubility of some trace elements. Using the equations predicting elemental solubility, we wrote a model for natural attenuation in the computer program Stella that considers atmospheric deposition as the input for trace elements and leaching as the output. Simulations were carried out for the 40 soils during 1,000 years with steady deposition inputs.
At current atmospheric deposition rates and the neutral to alkaline pH of these soils, attenuation occurred in most soils for Mo. For As, Cd, Co, Cu and Ni it occurred only in soils with abundant total element concentrations or an acidic pH. Minor retention occurred with Pb and Zn. Only Cd and Cu were of concern in leaching waters. The developed model can serve as a decision making tool in the selection of natural attenuation as a remediation strategy.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Khandoker, Rafiqul Alam. "Distribution of Heavy Metals and Trace Elements in Soils of Southwest Oregon". PDXScholar, 1997. https://pdxscholar.library.pdx.edu/open_access_etds/4691.

Texto completo

Resumen

Soil samples from 118 sites on 71 geologic units in southwest Oregon were collected and analyzed to determine the background concentrations of metals in soils of the region. Sites were chosen in areas that were relatively undisturbed by human activities. The U.S. Environmental Protection Agency approved total-recoverable method was used to recover metals from samples for analysis. The twenty six metals analyzed were: Ag, AI, As, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, La, Li, Mg, Mn, Mo, Na, Ni, Pb, Sb, Se, Tl, V and Zn. The Klamath Mountains followed by the Coast Range contain the highest soil concentrations of AI, Ca, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Ni, V and Zn. Soils of the Coastal Plain and High Lava Plains contain the lowest concentrations of these metals. Unusually high soil As concentrations are found at two sites in the Klamath Mountains. All Be and Cd values above laboratory's reporting limits are also from the Klamath Mountains and Coast Range. Concentrations of soil Ba and La are fairly uniform throughout the region. Soil Pb levels are generally low with a few exceptions in the Klamath Mountains, Coast and Cascade Ranges. The region west of the Cascade Range has higher soil Hg contents than in the east. Soil metal concentrations are generally much higher in the region west of the Cascade Range, excluding the Coastal Plain, than in the east with the exception ofNa, because of more ultramafic rocks and a wetter climate. Soil metal concentrations are directly related to soil development with the highest concentrations being found in well developed Alfisols and Ultisols and the lowest concentrations in poorly developed Entisols. Most metals have similar averages and ranges of concentration compared to the rest of the United States (U.S.). Metals with high values compared to the rest of the U.S. are Cr, Co, Cu, Mn and Ni. In general, AI, Co, Cr, Cu, Fe, La, Li, Mg, Na, Ni, and V are concentrated in the B horizon while Ba, Ca, Hg, K, Mn, Pb and Zn are concentrated in the A horizon.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Harley, Rachel. "Ion transport physiology and its interaction with trace element accumulation and toxicity in inanga (Galaxias maculatus)". Thesis, University of Canterbury. School of Biological Sciences, 2015. http://hdl.handle.net/10092/10738.

Texto completo

Resumen

Inanga (Galaxias maculatus) are a culturally and economically important fish species in New Zealand and abroad. However, very little is known about their ability to deal with trace element contamination. As a scaleless fish with the ability to survive in relatively extreme environments, they may not fit toxicity models (such as the biotic ligand model; BLM) based on other fish species. The aim of this study was to determine how this fish responds to elevated trace elements in both the laboratory and field in order to determine the applicability of these toxicity models. In order to determine the impacts of stress on ion transport and subsequent metal toxicity, inanga were exposed to handling stress and measures of ion uptake were collected. Handling stress was shown to result in increased ventilation rates, resulting in stimulated sodium (Na+) efflux. A compensatory increase in Na+ influx was also measured as a result of this stress. Inanga largely recovered from this ionoregulatory stress within 2 hours, with full recovery after 24 hours. This was indicative of a rapid homeostatic response for maintaining ion balance. Enhanced Na+ uptake in response to this stress resulted in increased copper (Cu) uptake in Cu-contaminated water, suggesting stressed fish will accumulate more Cu (and likely other Na+ mimics) than an unstressed fish. These results suggest a heightened vulnerability of inanga to this type of contaminant as a result of exercise stress during migrations. A combination of field and laboratory studies was used in order to measure trace element accumulation in inanga. In situ field studies showed changes to aluminum (Al) and iron (Fe) body burdens when inanga were placed in streams of varying trace element concentrations along the West Coast of the South Island. However, other trace elements measured did not alter over the period of exposure (9-10 days). Biochemical biomarker analysis showed no changes in the activity of Na+/K+-ATPase (NKA), but a marker of lipid peroxidation (thiobarbituric acid reactive substances; TBARS) was elevated in one stream. Analysis suggested that stream pH was the major driver of this effect, whether directly or via changes to metal bioavailability. Subsequent laboratory exposures (96 h) of inanga to 1.2, 2.7, 10.8, and 44 µg L-1 dissolved Fe and 5.6, 23.3, 60.7, and 128.7 µg L-1 dissolved zinc (Zn) showed no difference in whole body trace element accumulation, ammonia excretion, ion influx (Ca2+ and Na+), and TBARS. There were significant differences in oxygen consumption (MO2) after Fe exposures, with increases in the 2.7 and 44 µg L-1 dissolved Fe exposures. Laboratory exposure results suggest inanga are relatively insensitive to short-term Fe and Zn exposures. Both in vivo (whole body partitioning) and in vitro (Ussing chamber) techniques were used to determine the influence of cutaneous ion transport on preventing trace element accumulation. Results suggest inanga use their skin as an additional site of calcium (Ca2+) and Na+ uptake. This is the first study to confirm these ion transport capabilities in inanga, and revealed that up to 48% of Na+ uptake may occur across the skin. Pharmacological inhibition of Ca2+ uptake was achieved by known Ca2+ channel blockers (verapamil and lanthanum). Furthermore Fe and Zn impaired cutaneous Ca2+ transport, indicating that ion transport pathways in the skin modulate in response to these metals.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Fernandes, Felippe. "Histórico da urbanização e enriquecimento por metais em núcleos de sedimentos: geoquímica e geocronologia por 210Pb". Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/18/18139/tde-06072018-115332/.

Texto completo

Resumen

A barragem Mãe d\'Água foi construída em 1962, com o intuito de atender à demanda da Universidade Federal do Rio Grande do Sul UFRGS, mais precisamente o Instituto de Pesquisas Hidráulicas – IPH, porém, devido à falta de planejamento urbano, durante os últimos anos, vem acarretando uma diversificada série de passivos ambientais, como contaminantes orgânicos e/ou inorgânicos. Neste seguimento, o presente trabalho buscou avaliar as concentrações totais dos metais e a composição isotópica por chumbo 210 nas diferentes frações de sedimentos produzidos na bacia hidrográfica que compõe a barragem Mãe d\'Água e, assim, caracterizar a distribuição da concentração dos metais ao longo da coluna sedimentar e inferir quanto ao processo de urbanização da bacia hidrográfica caracterizando a evolução. Com referência nestas concentrações dos metais encontradas nos sedimentos, construir uma perspectiva do processo evolutivo da degradação ambiental na qual a bacia vem sendo submetida através de estudos de geocronologia (210Pb). As coletas das amostras foram realizadas em junho de 2014, sendo amostrados testemunhos sedimentares distribuídos no lago da referida barragem e o levantamento batimétrico. Para a extração dos testemunhos foi utilizado um amostrador de núcleo Piston core. Com os resultados obtidos, foramrepresentadas as concentrações dos metais Zn e Ni os quais apresentaram tendências de enriquecimento, a geocronologia datou as camadas assoreadas sendo o maior intervalo de 42 anos de deposição sedimentar, o volume do assoreamento ocupando aproximadamente 44% do volume útil do reservatório e a taxa de urbanização com tendências de crescimento e para o ano de 2014 com 88,42% da bacia urbanizada, configurando portanto uma distribuição espacial e estabelecendo correlações entre os estudos da sedimentação ao longo das últimas cinco décadas. As concentrações dos metais presentes nas amostras foram, também, comparadas com os valores de background do local para melhor visualizar o processo de enriquecimento dos sedimentos por ações antropogênicas. Foi possível concluir que com a ampliação das áreas urbanizadas, acarretou no aumentou das concentrações dos metais e no volume de sedimentos depositados no reservatório, onde a urbanização sem planejamento desta bacia é o principal fator poluidor.
The Municipality of Viamão is located in the metropolitan area of Porto Alegre, in the state of Rio Grande Sul. The Mãe d\'Água dam was built in 1962, with the purpose of meeting the demand of the Federal University of Rio Grande do Sul - UFRGS. Precisely because of the lack of urban planning during the last forty years, has led to a diversified series of environmental liabilities, such as organic and/or inorganic contaminants. The present work aimed to evaluate the total concentrations of metals and the isotopic composition per lead 210 in the different fractions of sediments produced in the watershed that make up the Mãe d\'Água dam and thus characterize the distribution of the concentration of metals along of the sedimentary column and infer about the process of urbanization of the watershed characterizing evolution. With reference to these concentrations of the metals found in the sediments, to construct a perspective of the evolutionary process of the environmental degradation in which the basin is being submitted through studies of geochronology (210Pb). Samples were collected in June 2014, and sediment deposited in the lake of the dam and bathymetric survey were sampled. A \"Piston core\" core sampler was used to extract the samples. With the results obtained, the concentrations of the metals Zn and Ni were presented, which presented enrichment tendencies, geochronology dating to the silted layers, silting volume occupying approximately 44% of the useful volume of the reservoir and the rate of urbanization with growth tendencies and for the year 2014 with 88% of the urbanized basin, thus constituting a spatial distribution and establishing correlations between sedimentation studies over the last four decades. The concentrations of the metals present in the samples were also compared with the background values of the site to better visualize the process of sediment enrichment by anthropogenic actions, where it was possible to verify that the expansion of the urbanized area increased the concentrations of the analyzed metals (Zn and Ni). It was possible to conclude that with the expansion of the urbanized areas, the increase of the concentrations of the metals and the volume of sediments deposited in the reservoir, where unplanned urbanization of this basin is the main polluting factor, resulted.

Los estilos APA, Harvard, Vancouver, ISO, etc.

LEMES, MARCOS J. de L. "Avaliacao de metais e elementos - traco em aguas e sedimentos das bacias hidrograficas dos rios Mogi - Guacu e Pardo, Sao Paulo". reponame:Repositório Institucional do IPEN, 2001. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10841.

Texto completo

Resumen

Made available in DSpace on 2014-10-09T12:44:36Z (GMT). No. of bitstreams: 0
Made available in DSpace on 2014-10-09T13:57:37Z (GMT). No. of bitstreams: 0
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Los estilos APA, Harvard, Vancouver, ISO, etc.

McCaslin, Luke. "Methodology for predicting microelectronic substrate warpage incorporating copper trace pattern characteristics". Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24641.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

SOARES, EUFEMIA P. "Caracterizacao de componentes inorganicos e tipos de polimeros em materiais plasticos metalizados". reponame:Repositório Institucional do IPEN, 2002. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11066.

Texto completo

Resumen

Made available in DSpace on 2014-10-09T12:47:44Z (GMT). No. of bitstreams: 0
Made available in DSpace on 2014-10-09T14:08:16Z (GMT). No. of bitstreams: 1 08316.pdf: 3292431 bytes, checksum: 351990e9278a88c1aa015f5320b23c32 (MD5)
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Los estilos APA, Harvard, Vancouver, ISO, etc.

GOMES, MARCELO da S. "Determinacao de elementos metalicos em sedimentos da Baia do Almirantado, Ilha Rei George, Penisula Antartica". reponame:Repositório Institucional do IPEN, 1999. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10762.

Texto completo

Resumen

Made available in DSpace on 2014-10-09T12:43:43Z (GMT). No. of bitstreams: 0
Made available in DSpace on 2014-10-09T13:58:06Z (GMT). No. of bitstreams: 1 06649.pdf: 21672592 bytes, checksum: ce3be21667c4c3939460ddeff380f31c (MD5)
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Los estilos APA, Harvard, Vancouver, ISO, etc.

Menendez-Alonso, Elena. "Trace metal and speciation analysis using ion-exchange and energy dispersive X-ray fluorescence spectrometry". Thesis, University of Plymouth, 2000. http://hdl.handle.net/10026.1/896.

Texto completo

Resumen

Studies have been carried out on specific ion-exchange (Dowex 50W-X8 and Dowex 1-X8) and chelation (Chelex-100) resins, in order to determine their physical and chemical characteristics, to understand and explain their limits of function and to optimise their use as substrates in trace metal and speciation measurement by EDXRF. Structural information was obtained by scanning electron microscopy and x-ray microanalysis showing a homogeneous distribution of functional groups and retained ions on both sectioned and whole resins. Particle size experiments performed on Dowex 50W-X8 (38 - 840 µm) showed that this parameter has no effect on the relationship between intensity of fluorescence and concentration or mass of resin. Inter-element effects were not observed in the analysis of multielemental specimens prepared on ion-exchange / chelation media by EDXRF. This indicates that the proposed method has a significant advantage when compared with other methodologies. A theoretical ‘model’, based on the formation of thin films on the surface of the resin beads, has been proposed in order to link and explain the effects observed in these experiments. The use of a batch retention system has shown distinct advantages over using columns in terms of linearity, accuracy, precision, rapidity and simplicity. Parameters such as pH and ionic strength of the solution, concentration of competing ions and volume of the sample have been proven to be critical. The maximum retention capacity has been determined as 3.2, 1.1 and 0.67 mEq/g for Dowex 50W-X8, Dowex 1-X8 and Chelex-100 respectively. The optimum mass of resin for XRF analysis was found to be 0.5 g, for all resins tested. The linear range covered 4 to 5 orders of magnitude. These findings show the potential of the investigated media to overcome instrumental and sample limitations. Based on the physico-chemical information found, methodologies for three different applications of the resins to EDXRF determinations have been developed and their analytical possibilities explored. The multi-elemental determination of metals in sewage sludge digests was achieved by retaining the metals on Dowex 50W-X8 at pH 2 and Chelex-100 at pH 4. Chelex-100 allows quantitative recoveries for Cu and Zn. A wider range of elements was determined on Dowex 50W-X8, although with poorer recoveries (60 - 90%). The limits of detection were 10 - 21 µg when Dowex 50W-X8 was used and 8 - 49 µg for Chelex-100. The method was validated by the analysis of a certified material. The determination of Kβ/Kα intensity ratios for Cr and Mn species and its potential as a tool for direct elemental speciation has also been studied. A difference in Kβ/Kα between the oxidation states of the analytes was only observed during the analysis of solutions of the metal species by EDXRF at the 98% level of confidence. Finally, the speciation and preconcentration of Cr(III) and Cr(VI) in waters has been performed by retention on Dowex 50W-X8 and Dowex 1-X8 followed by EDXRF determination. Efficient recoveries and preconcentration factors of up to 500 were achieved, leading to limits of detection of 30 µg/L for Cr(VI) and 40 µg/L for Cr(III). This method is simple, fast and inexpensive, allowing quantitative recoveries in the speciation of chromium in waste waters.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Más fuentes

Libros sobre el tema "Element trace metals"

J, Horowitz Arthur, ed. A primer on sediment-trace element chemistry. 2^a ed. Chelsea, Mich: Lewis Publishers, 1991.

Buscar texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Horowitz, Arthur J. A primer on sediment-trace element chemistry. 2^a ed. [Doraville, GA]: U.S. Geological Survey, 1991.

Buscar texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Horowitz, Arthur J. A primer on sediment-trace element chemistry. 2^a ed. [Doraville, GA]: U.S. Geological Survey, 1991.

Buscar texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Horowitz, Arthur J. A primer on sediment-trace element chemistry. 2^a ed. [Doraville, GA]: U.S. Geological Survey, 1991.

Buscar texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Loring, Douglas H. A final report on the ICES intercalibration for trace metals in marine sediments (1/TM/MS). Copenhagen: International Council for the Exploration of the Sea, 1987.

Buscar texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Loring, Douglas H. A final report on the ICES intercalibration for trace metals in marine sediments (1/TM/MS). Copenhagen, Denmark: International Council for the Exploration of the Sea, 1987.

Buscar texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Jones, Geoff. Metal concentrations in soils and produce from gardens in Flin Flon, Manitoba, 2002. Winnipeg: Manitoba Conservation, 2006.

Buscar texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Lund, L. J. Determination and predication of chemical forms of trace metals in sewage sludge and sludge-amended soils. Cincinnati, OH: U.S. Environmental Protection Agency, Water Engineering Research Laboratory, 1985.

Buscar texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Becker, Mark F. Selected trace metals and organic compounds and bioavailability of selected organic compounds in soils, Hackberry Flat, Tillman County, Oklahoma, 1994-95. [Oklahoma City, OK]: U.S. Dept. of Interior, U.S. Geological Survey, 1997.

Buscar texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Valette-Silver, Nathalie J. Behavior of toxic metals during contact of synthetic coal leachates with Maryland coastal plain soil. [Annapolis? Md: Maryland Dept. of Natural Resources, 1995.

Buscar texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Más fuentes

Capítulos de libros sobre el tema "Element trace metals"

Samson, P. J., J. Keeler, C. Borego, P. Buseck, R. S. Cambray, A. Contreraz-Lopez, H. Grassl et al. "Modelling Trace Element Transport". En Control and Fate of Atmospheric Trace Metals, 349–54. Dordrecht: Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-009-2315-7_17.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Merlot, Sylvain, Vanesa Sanchez Garcia de la Torre y Marc Hanikenne. "Physiology and Molecular Biology of Trace Element Hyperaccumulation". En Agromining: Farming for Metals, 155–81. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-58904-2_8.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Merlot, Sylvain, Vanesa Sanchez Garcia de la Torre y Marc Hanikenne. "Physiology and Molecular Biology of Trace Element Hyperaccumulation". En Agromining: Farming for Metals, 93–116. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-61899-9_6.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Keeler, Gerald J. y Perry J. Samson. "On the Spatial Representativeness of Trace Element Ratios". En Control and Fate of Atmospheric Trace Metals, 115–32. Dordrecht: Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-009-2315-7_7.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Smodiš, B. y A. Bleise. "Biomonitoring Trace Element Atmospheric Deposition: An Internationally Harmonised Approach". En Radionuclides and Heavy Metals in Environment, 157–64. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-010-0993-5_24.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Sarkar, Santosh Kumar. "Trace Element Contamination in Surface Sediment of Sundarban Wetland". En Trace Metals in a Tropical Mangrove Wetland, 79–100. Singapore: Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-2793-2_3.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Pogatscher, Stefan, Helmut Antrekowitsch, Marion Werinos, Gunther Rank, Anna Kais, Ramona Prillhofer, Jorg F. Loffler y Peter J. Uggowitzer. "Statistical and Thermodynamic Optimization of Trace-Element Modified Al-Mg-Si-Cu Alloys". En Light Metals 2015, 263–70. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2015. http://dx.doi.org/10.1002/9781119093435.ch45.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Pogatscher, Stefan, Helmut Antrekowitsch, Marion Werinos, Gunther Rank, Anna Kaiß, Ramona Prillhofer, Jörg F. Löffler y Peter J. Uggowitzer. "Statistical and Thermodynamic Optimization of Trace-Element Modified Al-Mg-Si-Cu Alloys". En Light Metals 2015, 265–70. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-48248-4_45.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Gaertner, Heiko, Arne Petter Ratvik y Thor Anders Aarhaug. "Trace Element Concentration in Particulates from Pot Exhaust and Depositions in Fume Treatment Facilities". En Light Metals 2013, 769–74. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2013. http://dx.doi.org/10.1002/9781118663189.ch131.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Gaertner, Heiko, Arne Petter Ratvik y Thor Anders Aarhaug. "Trace Element Concentration in Particulates from Pot Exhaust and Depositions in Fume Treatment Facilities". En Light Metals 2013, 769–74. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-65136-1_131.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Actas de conferencias sobre el tema "Element trace metals"

Dimov, Stamen S. "Trace element analysis of precious metals in minerals by time-of-flight resonance ionization mass spectrometry (TOF-RIMS)". En RESONANCE IONIZATION SPECTROSCOPY 2000: Laser Ionization and Applications Incorporating RIS; 10th International Symposium. AIP, 2001. http://dx.doi.org/10.1063/1.1405582.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Cross, E. S., A. Sappok, E. C. Fortner, J. F. Hunter, J. T. Jayne, W. A. Brooks, T. B. Onasch et al. "Real-Time Measurements of Engine-Out Trace Elements: Application of a Novel Soot Particle Aerosol Mass Spectrometer for Emissions Characterization". En ASME 2011 Internal Combustion Engine Division Fall Technical Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/icef2011-60100.

Texto completo

Resumen

Lubricant-derived trace element emissions are the largest contributors to the accumulation of incombustible ash in diesel particulate filters (DPF), eventually leading to filter plugging and an increase in engine fuel consumption. Particulate trace element emissions also pose adverse health effects and are the focus of increasingly stringent air quality regulations. To date, the rates and physical and chemical properties of lubricant-derived additive emissions are not well characterized, largely due to the difficulties associated with conducting the measurements. This work investigated the potential for conducting real-time measurements of lubricant-derived particle emissions. The experiment used the Soot Particle Aerosol Mass Spectrometer (SP-AMS) developed by Aerodyne Research to measure the size, mass and composition of submicron particles in the exhaust. Results confirm the ability of the SP-AMS to measure engine-out emissions of calcium, zinc, magnesium, phosphorous, and sulfur. Further, emissions of previously difficult to detect elements, such as boron, and low-level engine wear metals, such as lead, were also measured. This paper provides an overview of the results obtained with the SP-AMS, and demonstrates the utility of applying real-time techniques to engine-out and tailpipe-out trace element emissions. The SP-AMS used in this study was developed for real-time characterization of refractory particles (i.e. black carbon or soot) in the ambient atmosphere. The instrument consists of an intra-cavity laser (1064 nm) for particle vaporization followed by electron impact ionization and ion detection via a time-of-flight mass spectrometer. Application of the SP-AMS for engine exhaust characterization followed a two-part approach: (1) measurement validation, and (2) measurement of engine-out exhaust. Measurement validation utilized a diesel burner with precise control of lubricant consumption. Results showed a good correlation between CJ-4 oil consumption and measured levels of lubricant-derived trace elements in the particle phase. Following measurement validation, the SP-AMS measured engine-out emissions from a medium-duty diesel engine, operated over a standard speed/load matrix. This work demonstrates the utility of state-of-the-art online techniques (such as the SP-AMS) to measure engine-out emissions, including trace species derived from lubricant additives. Results help optimize the combined engine-lubricant-aftertreatment system and provide a real-time characterization of emissions. As regulations become more stringent and emission controls more complex, advanced measurement techniques with high sensitivity and fast time response will become an increasingly important part of engine characterization studies.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Zhong, Zhaoping, Baosheng Jin, Yaji Huang, Hongcang Zhou, Davide Ross y Masayuki Horio. "Study on Pollutants Emission Characteristic of Coal Gasification in a Fluidized Bed Test Rig". En 18th International Conference on Fluidized Bed Combustion. ASMEDC, 2005. http://dx.doi.org/10.1115/fbc2005-78070.

Texto completo

Resumen

This paper presents the results of coal gasification in a fluidized bed test rig of Xuzhou bituminous coal. The diameter of the fluidized bed combustor is 0.1m and the height is 4.22m. The bed temperature is maintained by a method of high temperature flue gas interline heating to overcome high heat losses associated with a oil burner. Test results are reported for variations in the bed temperature, air to coal, steam to coal and Ca to S ratio and their influence on gas yields and desulphurization efficiency. The distribution of polycyclic aromatic hydrocarbons (PAHs) and heavy metal trace elements into the char and syngas are also presented. The molar contents for CH4 and H2 in the coal syngas are found to decrease with increasing air to coal feed ratio from 2.5 to 5, while the content of CO shows little variation. Increasing the steam to coal feed ratio from 0.4 to 0.65 results in all three of the main gas components measured to form a local maximum content at a steam/coal feed ratio of 0.55. The efficiency of desulphurization improves as the ratio of Ca to S, air to coal and the bed temperature are increased, while decreasing with increasing steam to coal feed ratios. The volatile trace element species in decreasing order of relative mass ratio released into the gas phase are Hg, Se, As, Co, Cr, Cd, Cu, and Zn. Besides Hg, Se, and As, for all other trace heavy metals the majority of their mass distribution remains within the char with the proportion contained within char always greater than their combined yields in the coal syngas and slag. The total PAHs in the coal syngas is greater than that contained in the original coal and this indicates that PAHs are formed during the coal gasification process.

Los estilos APA, Harvard, Vancouver, ISO, etc.

YOSHIKI, YUMIKO. "CHEMILUMINESCENCE ENHANCEMENT EFFECT OF TRACE METAL ELEMENTS". En Chemistry, Biology and Applications. WORLD SCIENTIFIC, 2007. http://dx.doi.org/10.1142/9789812770196_0061.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Mora, Diego F., Markus Niffenegger y Roman Mukin. "Crack Propagation Modeling in a PWR Under PTS Using XFEM". En ASME 2020 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/pvp2020-21026.

Texto completo

Resumen

Abstract The finite element simulation of fracture propagation of BCC metals is challenging, as it needs to incorporate the brittle, ductile-brittle transition and ductile behavior presented by the fracture toughness. In this contribution, we restrict ourselves to the use of XFEM method to simulate the cleavage fracture due to initial flaws in the reactor pressure vessel of a reference design of the two-loop PWR nuclear power plant. A hypothetical large break loss of coolant accident is selected as accident scenario to obtain the loading conditions under which the crack is subjected. The thermal-mechanical calculation is performed using a finite element model of the whole RPV and the initial and boundary conditions are determined from the thermal-hydraulic simulation of the transient in TRACE. The method proposed in this contribution is based on the cohesive segment approach implemented in ABAQUS, which requires the definition of the damage properties of the material. The segment approach does not use the fracture toughness as failure criterion. Instead, it uses a traction separation law that is able to capture the brittle fracture behavior of ferritic steel. The crack propagation in XFEM uses a propagation criterion based on a cohesive damage initiation criterion and a damage evolution model. In order to implement the damage evolution model, the fracture energy release rate is directly related to the fracture toughness. The postulated crack is inserted in a submodel to reduce the computational cost of the calculation. The location of such submodel corresponds to the region of the core that suffers maximum irradiation and is subjected to high tensile stresses due to the cooling plume generated during the transient PTS cooling. The crack propagation analysis of postulated axial crack showed that its propagation happens in axial direction in those finite elements close to the inner surface because the energy release rate GI is larger than the critical energy release rate GIC. At the deepest point of the crack, the stresses in the finite element fulfil the damage initiation criterion but the crack does not propagate in radial direction (GI < GIC).

Los estilos APA, Harvard, Vancouver, ISO, etc.

Harkness, Jennifer S. y Thomas H. Darrah. "TRACE METAL AND RARE EARTH ELEMENT CHEMISTRY OF MODERN HUMAN BONE". En GSA Annual Meeting in Indianapolis, Indiana, USA - 2018. Geological Society of America, 2018. http://dx.doi.org/10.1130/abs/2018am-321810.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Goto, Yasunori, Hiroomi Eguchi y Masaru Iida. "Method of Detecting Trace Metal Contamination in Thick-Film SOI Device". En ISTFA 2005. ASM International, 2005. http://dx.doi.org/10.31399/asm.cp.istfa2005p0220.

Texto completo

Resumen

Abstract In the automotive IC using thick-film silicon on insulator (SOI) semiconductor device, if the gettering capability of a SOI wafer is inadequate, electrical characteristics degradation by metal contamination arises and the yield falls. At this time, an automotive IC was made experimentally for evaluation of the gettering capability as one of the purposes. In this IC, one of the output characteristics varied from the standard, therefore failure analysis was performed, which found trace metal elements as one of the causes. By making full use of 3D perspective, it is possible to fabricate a site-specific sample into 0.1 micrometre in thickness without missing a failure point that has very minute quantities of contaminant in a semiconductor device. Using energy dispersive X-ray, it is possible to detect trace metal contamination at levels 1E12 atoms per sq cm. that are conventionally detected only by trace element analysis.

Los estilos APA, Harvard, Vancouver, ISO, etc.

PILECKA, Jovita, Inga GRINFELDE, Inga STRAUPE y Oskars PURMALIS. "THE ANTHROPOGENIC AIR POLLUTION SOURCE IDENTIFICATION IN URBAN AREAS USING SNOW SAMPLING". En RURAL DEVELOPMENT. Aleksandras Stulginskis University, 2018. http://dx.doi.org/10.15544/rd.2017.180.

Texto completo

Resumen

The anthropogenic sources of air pollution such as transport, energetics, household heating and industry generate different trace element footprint. The urban planning is one of tool to reduce air pollution with trace elements. The aim of this study is to identify air pollution sources in Jelgava city using trace elements. The snow sampling were collected during January and February 2017. The January snow samples characterise average Jelgava city air pollution. However, February characterises intensive tourism impact on total air quality of Jelgava city. The snow samples were analysed using inductively coupled plasma spectrometer (ICP-OES). The data analysis consists of three stages. First, data verification and development of waste burning; burning of oil and fossil materials; wastewater treatment and utilisation of sewage sludge; transport; metal industry and fireworks typical pollution trace element data sets. Second, the cluster analysis of each data set, by developing three groups of pollution level for each pollution source. Third the results of clusters were analysed using GIS, and the areas with different air pollution risks were identified. The results show strong evidence of transport and household impact on air quality.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Li, Debo, QiSheng Xu, Cao Xin, Xudan Ren y Jianyi Lu. "Emission Control of Trace Heavy Metal Elements in Coal-fired Power Plants". En 2015 2nd International Conference on Machinery, Materials Engineering, Chemical Engineering and Biotechnology. Paris, France: Atlantis Press, 2016. http://dx.doi.org/10.2991/mmeceb-15.2016.109.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Lee, Khanghyun, Sang-Bum Hong, Jong Ik Lee y Soon Do Hur. "Seasonal Changes in Atmospheric Inputs of Trace Metals and Halogen Elements at EGRIP, Greenland". En Goldschmidt2020. Geochemical Society, 2020. http://dx.doi.org/10.46427/gold2020.1437.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Informes sobre el tema "Element trace metals"

Scholz, Florian. Sedimentary fluxes of trace metals, radioisotopes and greenhouse gases in the southwestern Baltic Sea Cruise No. AL543, 23.08.2020 – 28.08.2020, Kiel – Kiel - SEDITRACE. GEOMAR Helmholtz Centre for Ocean Research Kiel, noviembre de 2020. http://dx.doi.org/10.3289/cr_al543.

Texto completo

Resumen

R/V Alkor Cruise AL543 was planned as a six-day cruise with a program of water column and sediment sampling in Kiel Bight and the western Baltic Sea. Due to restrictions related to the Covid-19 pandemic, the original plan had to be changed and the cruise was realized as six oneday cruises with sampling in Kiel Bight exclusively. The first day was dedicated to water column and sediment sampling for radionuclide analyses at Boknis Eck and Mittelgrund in Eckernförde Bay. On the remaining five days, water column, bottom water, sediment and pore water samples were collected at eleven stations covering different types of seafloor environment (grain size, redox conditions) in western Kiel Bight. The data and samples obtained on cruise AL543 will be used to investigate (i) the sedimentary cycling of bio-essential metals (e.g., nickel, zinc, and their isotopes) as a function of variable redox conditions, (ii) the impact of submarine groundwater discharge and diffusive benthic fluxes on the distribution of radium and radon as well as greenhouse gases (methane and nitrous oxide) in the water column, and (iii) to characterize and quantify the impact of coastal erosion on sedimentary iron, phosphorus and rare earth element cycling in Kiel Bight.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Khandoker, Rafiqul. Distribution of Heavy Metals and Trace Elements in Soils of Southwest Oregon. Portland State University Library, enero de 2000. http://dx.doi.org/10.15760/etd.6575.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Jonasson, I. R., E M Hillary, M. D. Hannington, P. Mercier-Langevin y D. Diekrup. Trace-element geochemistry of ore-mineral separates from selected Canadian base-metal deposits. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2020. http://dx.doi.org/10.4095/326134.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Goodarzi, F., H. Sanei y W. F. Duncan. Deposition of trace elements in the Trail region, British Columbia; an assessment of the environmental effect of a base metal smelter on land. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2003. http://dx.doi.org/10.4095/214034.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Kyllönen, Katriina, Karri Saarnio, Ulla Makkonen y Heidi Hellén. Verification of the validity of air quality measurements related to the Directive 2004/107/EC in 2019-2020 (DIRME2019). Finnish Meteorological Institute, 2020. http://dx.doi.org/10.35614/isbn.9789523361256.

Texto completo

Resumen

This project summarizes the results from 2000–2020and evaluates the trueness andthequality control (QC) procedures of the ongoing polycyclic aromatic hydrocarbon (PAH)and trace element measurements in Finlandrelating to Air Quality (AQ) Directive 2004/107/EC. The evaluation was focused on benzo(a)pyrene and other PAH compounds as well as arsenic, cadmium and nickel in PM10and deposition. Additionally, it included lead and other metals in PM10and deposition, gaseous mercury and mercury deposition, andbriefly other specificAQ measurements such as volatile organic compounds (VOC)and PM2.5chemical composition. This project was conducted by the National Reference Laboratory on air quality and thiswas the first time these measurements were assessed. A major part of the project was field and laboratory audits of the ongoing PAH and metal measurements. Other measurements were briefly evaluated through interviews and available literature. In addition, the national AQ database, the expertise of local measurement networks and related publications were utilised. In total, all theseven measurement networks performing PAH and metal measurements in 2019–2020took part in the audits. Eleven stations were audited while these measurements are performed at 22 AQ stations in Finland. For the large networks, one station was chosen to represent the performance of the network. The audits included also six laboratories performing the analysis of the collected samples. The audits revealed the compliance of the measurements with the AQ Decree 113/2017, Directive 2004/107/EC and Standards of the European Committee for Standardization(CEN). In addition, general information of the measurements, instruments and quality control procedures were gained. The results of the laboratory audits were confidential,but this report includes general findings, and the measurement networks were informed on the audit results with the permission of the participating laboratories. As a conclusion, the measurementmethodsusedwere mainly reference methods. Currently, all sampling methods were reference methods; however, before 2018 three networks used other methods that may have underestimated concentrations. Regarding these measurements, it should be noted the results are notcomparable with the reference method. Laboratory methods were reference methods excluding two cases, where the first was considered an acceptable equivalent method. For the other, a change to a reference method was strongly recommended and this realized in 2020. For some new measurements, the ongoing QC procedures were not yet fully established, and advice were given. Some networks used consultant for calibration and maintenance, and thus theywere not fully aware of the QC procedures. EN Standards were mostly followed. Main concerns were related to the checks of flow and calculation of measurement uncertainty, and suggestions for improvement were given. When the measurement networks implement the recommendations given inthe audits, it can be concluded that the EN Standards are adequately followed in the networks. In the ongoing sampling, clear factors risking the trueness of the result were not found. This applies also for the laboratory analyses in 2020. One network had concentrations above the target value, and theindicative measurementsshould be updated to fixed measurements.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Water-quality assessment of the Kentucky River Basin, Kentucky; distribution of metals and other trace elements in sediment and water, 1987-90. US Geological Survey, 1995. http://dx.doi.org/10.3133/wri944134.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

Ofrecemos descuentos en todos los planes premium para autores cuyas obras están incluidas en selecciones literarias temáticas. ¡Contáctenos para obtener un código promocional único!