Literatura académica sobre el tema "Solute deposition"
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Artículos de revistas sobre el tema "Solute deposition"
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Piatek, K. B., S. F. Christopher y M. J. Mitchell. "Spatial and temporal dynamics of stream chemistry in a forested watershed impacted by atmospheric deposition". Hydrology and Earth System Sciences Discussions 5, n.º 4 (8 de septiembre de 2008): 2581–622. http://dx.doi.org/10.5194/hessd-5-2581-2008.
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Abstract. We analyzed spatial and temporal dynamics of solute chemistry in a forest watershed impacted by atmospheric deposition in the Adirondack Mountains of New York State, USA. Spatial dynamics of solute chemistry and natural abundance isotopes of nitrate (15N and 18O) were examined in 6 locations and the watershed outlet in 2001 and 2002. Temporal dynamics were examined during 5 discharge periods: winter, snowmelt, spring, summer, and fall, which were based on discharge levels at the outlet. Solute concentrations were statistically significantly different (p≤0.05) among stream sampling locations and discharge periods, with no interaction effects. Groundwater sources located in upper watershed controlled stream chemistry at higher elevations with highest pH, Ca2+, sum of base cations, Si, NO3-, total N, and SO42- and lowest Al concentrations. Two low elevation wetlands had a substantial influence over stream chemistry at those locations contributing lowest NO3-, total N, and highest DOC and DON. Snowmelt exhibited among the lowest pH, sum of base cations, and SO42-, and highest NO3-, total N, DON, and total Al; snowmelt appeared to dilute groundwater, and flush stored soil-derived solutes. Summer discharge, composed mainly of groundwater, exhibited the lowest flow, among the highest Mg2+, Ca2+, and lowest DON, DOC, and total Al concentrations. Isotopic analysis together with patterns of NH4+ versus NO3- dynamics indicated that NO3- was microbial, generated in fall and accumulated in winter in upper watershed soils, and flushed to stream during high discharge events. Highest discharge in snowmelt 2001, a summer drought in 2002, and fall storms following the drought were further evaluated for their specific effects on stream chemistry. Snowmelt 2001 had the lowest pH and highest NO3-, base flow during summer drought had the lowest total Al, and storms in fall 2002 had highest SO42- of all periods, but all other solute concentrations were comparable to other discharge periods in this study. Depending on objectives, watershed outlet alone may sufficiently represent solute dynamics in the watershed, and high-discharge events may sufficiently describe solute fluxes for the watershed.
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Sharp, Martin, Mark Skidmore y Peter Nienow. "Seasonal and spatial variations in the chemistry of a High Arctic supraglacial snow cover". Journal of Glaciology 48, n.º 160 (2002): 149–58. http://dx.doi.org/10.3189/172756502781831683.
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AbstractThis paper describes the physical and chemical properties of the snow- pack on John Evans Glacier, Ellesmere Island, Canadian Arctic Archipelago, and investigates the controls on snowpack solute concentrations and atmospheric deposition. The snowpack contains three layers that are traceable across the whole glacier. These represent fall accumulation that has been metamorphosed to depth hoar, winter accumulation mixed with snow reworked by wind from the underlying depth hoar, and spring accumulation mixed with wind-reworked snow. The seasonal cycle in snow chemistry closely reflects changes in the composition of the atmospheric aerosol at Alert, with some modification of NO3− concentrations by post-depositional processes. Mean water-weighted solute concentrations in the snowpack are largely independent of accumulation, while atmospheric deposition tends to increase with accumulation. This suggests that, for most species, wet deposition is the dominant depositional process throughout the year. However, concentrations of Ca2+ and K+ increase with both accumulation and elevation, implying an enhanced input from dry deposition of soil dust above 800 m elevation. Concentrations of SO42− are inversely related to accumulation, especially in the winter layer, suggesting a significant input from non-precipitating events, such as dry deposition or riming, during this period of very limited snowfall.
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Yde, Jacob C., Mette Riger-Kusk, Hanne H. Christiansen, N. Tvis Knudsen y Ole Humlum. "Hydrochemical characteristics of bulk meltwater from an entire ablation season, Longyearbreen, Svalbard". Journal of Glaciology 54, n.º 185 (2008): 259–72. http://dx.doi.org/10.3189/002214308784886234.
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AbstractThe ionic and isotopic characteristics of bulk waters emanating from the cold-based Longyearbreen, central Svalbard, in 2004 are examined to determine lithological, hydrological and glaciological controls on water composition, solute provenance and chemical denudation. The geology consisted of reactive coal seams and associated sedimentary rocks. Acidity caused by microbial-mediated oxidation of sulfides and, to a lesser extent, nitrogen-bearing minerals was neutralized by congruent dissolution of dolomite and incongruent weathering of silicates in open-system subglacial drainage channels. The ablation season was divided into an early melt season, a peak-flow period and a late melt season. The runoff distribution during these periods was 1.7%, 89.7% and 8.6%, respectively, whereas the solute flux distribution was 1.9%, 82.1% and 16.0%, respectively. Comparisons between different annual solute flux estimation methods indicated that extrapolation of peak-flow period data significantly underestimated both the early- and late-melt-season solute fluxes. About 3.8% of the solutes derived from sea-salt spray, 0.7% from acid aerosol deposition and 95.5% from crustal/organic sources. The physical and chemical conditions resulted in diffusion of CO2 rather than atmospheric drawdown. The cation-equivalent weathering rate and the crustal solute yield were 322 ΣmEq+m−2 a−1 and 22 t km−2 a−1, respectively, which are within the regional range of Svalbard. However, the chemical weathering intensity was as high as 940 ΣmEq+ m−3 owing to the relatively low specific discharge of 0.34 m a−1.
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Chin-Tai Chen, Ching-Chang Chieng y Fan-Gang Tseng. "Uniform Solute Deposition of Evaporable Droplet in Nanoliter Wells". Journal of Microelectromechanical Systems 16, n.º 5 (octubre de 2007): 1209–18. http://dx.doi.org/10.1109/jmems.2007.904327.
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Tanaka, Tadashi. "THE ROLE OF SUBSURFACE FLOW DYNAMIC ON SPATIAL AND TEMPORAL VARIATION OF WATER CHEMISTRY IN A HEADWATER CATCHMENT". Indonesian Journal of Agricultural Science 8, n.º 1 (25 de octubre de 2016): 17. http://dx.doi.org/10.21082/ijas.v8n1.2007.17-30.
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Variation of water chemistry does not merely occur due to in situ chemical process, but also transport process. The study was carried out to address the role of subsurface flow dynamic on spatial and temporal variation of water chemistry in a headwater catchment. Hydrometric and hydrochemistry measurements were done in transect with nested piezometers, tensiometers, and suction samplers at different depths across hillslope and riparian zone in a 5.2 ha first-order drainage of the Kawakami experimental basin, Nagano, Central Japan from August 2000 to August 2001. Spatial variation of solute concentration was defined by the standard deviation and coefficient of variation of the seasonal observed concentrations. Autocorrelation analysis was performed to define temporal variation of solute concentration. The results showed that spatial variation of water chemistry was mainly influenced by the variation of subsurface flow through the hillslope and riparian zone. Solute concentration in the deep riparian groundwater was almost three times higher than that in the hillslope segment. A prominent downward flow in deep riparian groundwater zone provided transport of solutes to the deeper layer. Time series analysis showed that in the deep riparian groundwater, Ca2+, Mg2+, SO42- and HCO3- concentrations underwent a random process, Na+ concentration of a random process superimposed by a trend process, and SiO2 of a random process superimposed by a periodic process. Near the riparian surface, SO42- concentration was composed of a random process superimposed by a periodic process, whereas other solutes were mainly in a random process. In the hillslope soil water, there was no trend observed for the Na+ concentration, but there were for Ca2+ and Mg2+. The magnitude and direction of subsurface flow across hillslope and riparian zone created transport and deposition processes that changed solute concentration spatially and temporally.
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Tanaka, Tadashi. "THE ROLE OF SUBSURFACE FLOW DYNAMIC ON SPATIAL AND TEMPORAL VARIATION OF WATER CHEMISTRY IN A HEADWATER CATCHMENT". Indonesian Journal of Agricultural Science 8, n.º 1 (25 de octubre de 2016): 17. http://dx.doi.org/10.21082/ijas.v8n1.2007.p17-30.
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Variation of water chemistry does not merely occur due to in situ chemical process, but also transport process. The study was carried out to address the role of subsurface flow dynamic on spatial and temporal variation of water chemistry in a headwater catchment. Hydrometric and hydrochemistry measurements were done in transect with nested piezometers, tensiometers, and suction samplers at different depths across hillslope and riparian zone in a 5.2 ha first-order drainage of the Kawakami experimental basin, Nagano, Central Japan from August 2000 to August 2001. Spatial variation of solute concentration was defined by the standard deviation and coefficient of variation of the seasonal observed concentrations. Autocorrelation analysis was performed to define temporal variation of solute concentration. The results showed that spatial variation of water chemistry was mainly influenced by the variation of subsurface flow through the hillslope and riparian zone. Solute concentration in the deep riparian groundwater was almost three times higher than that in the hillslope segment. A prominent downward flow in deep riparian groundwater zone provided transport of solutes to the deeper layer. Time series analysis showed that in the deep riparian groundwater, Ca2+, Mg2+, SO42- and HCO3- concentrations underwent a random process, Na+ concentration of a random process superimposed by a trend process, and SiO2 of a random process superimposed by a periodic process. Near the riparian surface, SO42- concentration was composed of a random process superimposed by a periodic process, whereas other solutes were mainly in a random process. In the hillslope soil water, there was no trend observed for the Na+ concentration, but there were for Ca2+ and Mg2+. The magnitude and direction of subsurface flow across hillslope and riparian zone created transport and deposition processes that changed solute concentration spatially and temporally.
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Gogoi, Prerona, Arun Chattopadhyay y Partho Sarathi Gooh Pattader. "Toward Controlling Evaporative Deposition: Effects of Substrate, Solvent, and Solute". Journal of Physical Chemistry B 124, n.º 50 (9 de diciembre de 2020): 11530–39. http://dx.doi.org/10.1021/acs.jpcb.0c08045.
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Bondesson, Eva, Thomas Bengtsson, Lars-Erik Nilsson y Per Wollmer. "Site of deposition and absorption of an inhaled hydrophilic solute". British Journal of Clinical Pharmacology 63, n.º 6 (junio de 2007): 722–31. http://dx.doi.org/10.1111/j.1365-2125.2006.02835.x.
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Lin, Jixiang, Xiaoyuan Peng, Xiaoyu Hua, Shengnan Sun, Yingnan Wang y Xiufeng Yan. "Effects of arbuscular mycorrhizal fungi on Leymus chinensis seedlings under salt–alkali stress and nitrogen deposition conditions: from osmotic adjustment and ion balance". RSC Advances 8, n.º 26 (2018): 14500–14509. http://dx.doi.org/10.1039/c8ra00721g.
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Shang, Yidan, Kiao Inthavong, Dasheng Qiu, Narinder Singh, Fajiang He y Jiyuan Tu. "Prediction of nasal spray drug absorption influenced by mucociliary clearance". PLOS ONE 16, n.º 1 (28 de enero de 2021): e0246007. http://dx.doi.org/10.1371/journal.pone.0246007.
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Evaluation of nasal spray drug absorption has been challenging because deposited particles are consistently transported away by mucociliary clearance during diffusing through the mucus layer. This study developed a novel approach combining Computational Fluid Dynamics (CFD) techniques with a 1-D mucus diffusion model to better predict nasal spray drug absorption. This integrated CFD-diffusion approach comprised a preliminary simulation of nasal airflow, spray particle injection, followed by analysis of mucociliary clearance and drug solute diffusion through the mucus layer. The spray particle deposition distribution was validated experimentally and numerically, and the mucus velocity field was validated by comparing with previous studies. Total and regional drug absorption for solute radius in the range of 1 − 110nm were investigated. The total drug absorption contributed by the spray particle deposition was calculated. The absorption contribution from particles that deposited on the anterior region was found to increase significantly as the solute radius became larger (diffusion became slower). This was because the particles were consistently moved out of the anterior region, and the delayed absorption ensured more solute to be absorbed by the posterior regions covered with respiratory epithelium. Future improvements in the spray drug absorption model were discussed. The results of this study are aimed at working towards a CFD-based integrated model for evaluating nasal spray bioequivalence.
Tesis sobre el tema "Solute deposition"
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Ness, Lindsay Anne. "Solute deposition to an upland catchment : spatial patterns, temporal trends and links to stream water chemistry". Thesis, University of East Anglia, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.429683.
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Zimmermann, Alexander. "Rainfall redistribution and change of water quality in tropical forest canopies : patterns and persistence". Phd thesis, Universität Potsdam, 2009. http://opus.kobv.de/ubp/volltexte/2009/3255/.
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Motivations and research objectives: During the passage of rain water through a forest canopy two main processes take place. First, water is redistributed; and second, its chemical properties change substantially. The rain water redistribution and the brief contact with plant surfaces results in a large variability of both throughfall and its chemical composition. Since throughfall and its chemistry influence a range of physical, chemical and biological processes at or below the forest floor the understanding of throughfall variability and the prediction of throughfall patterns potentially improves the understanding of near-surface processes in forest ecosystems. This thesis comprises three main research objectives. The first objective is to determine the variability of throughfall and its chemistry, and to investigate some of the controlling factors. Second, I explored throughfall spatial patterns. Finally, I attempted to assess the temporal persistence of throughfall and its chemical composition.
Research sites and methods: The thesis is based on investigations in a tropical montane rain forest in Ecuador, and lowland rain forest ecosystems in Brazil and Panama. The first two studies investigate both throughfall and throughfall chemistry following a deterministic approach. The third study investigates throughfall patterns with geostatistical methods, and hence, relies on a stochastic approach.
Results and Conclusions: Throughfall is highly variable. The variability of throughfall in tropical forests seems to exceed that of many temperate forests. These differences, however, do not solely reflect ecosystem-inherent characteristics, more likely they also mirror management practices. Apart from biotic factors that influence throughfall variability, rainfall magnitude is an important control. Throughfall solute concentrations and solute deposition are even more variable than throughfall. In contrast to throughfall volumes, the variability of solute deposition shows no clear differences between tropical and temperate forests, hence, biodiversity is not a strong predictor of solute deposition heterogeneity. Many other factors control solute deposition patterns, for instance, solute concentration in rainfall and antecedent dry period. The temporal variability of the latter factors partly accounts for the low temporal persistence of solute deposition. In contrast, measurements of throughfall volume are quite stable over time. Results from the Panamanian research site indicate that wet and dry areas outlast consecutive wet seasons. At this research site, throughfall exhibited only weak or pure nugget autocorrelation structures over the studies lag distances. A close look at the geostatistical tools at hand provided evidence that throughfall datasets, in particular those of large events, require robust variogram estimation if one wants to avoid outlier removal. This finding is important because all geostatistical throughfall studies that have been published so far analyzed their data using the classical, non-robust variogram estimator.Motivation und Zielsetzung: Wenn Regen durch ein Kronendach fällt lassen sich zwei Prozesse beobachten: das Regenwasser wird umverteilt und die chemische Qualität des Wassers verändert sich erheblich. Die Prozesse im Kronenraum resultieren in einer hohen Variabilität des Bestandsniederschlags und dessen chemischer Zusammensetzung. Bestandsniederschlag beeinflusst eine Reihe von physikalischen, chemischen und biologischen Prozessen am Waldboden. Daher können Untersuchungen zur Variabilität und zu Mustern im Bestandsniederschlag helfen, bodennahe Prozesse besser zu verstehen. Diese Dissertation behandelt hauptsächlich drei Aspekte. Erstens, die Arbeit beschäftigt sich mit der Erfassung der Variabilität im Bestandsniederschlag und dessen chemischer Zusammensetzung, zudem werden Einflussfaktoren dieser Variabilität untersucht. Des Weiteren beschäftigt sich die Arbeit mit räumlichen Mustern des Bestandsniederschlagswassers, und drittens wird die zeitliche Stabilität des Bestandsniederschlags und dessen chemischer Zusammensetzung betrachtet. Untersuchungsgebiete und Methoden: Diese Dissertation basiert auf Untersuchungen in einem tropischen Bergregenwald in Ecuador, sowie Studien in tropischen Tieflandregenwäldern in Brasilien und Panama. Die ersten zwei Studien untersuchen Bestandsniederschlag und dessen chemische Zusammensetzung mit Hilfe deterministischer Methoden. Die Arbeit in Panama nutzt geostatistische Methoden zur Beschreibung von Bestandsniederschlagsmustern und verfolgt somit einen stochastischen Ansatz. Ergebnisse und Schlussfolgerungen: Die Variabilität des Bestandsniederschlages ist hoch; das heißt, die Menge des auf den Waldboden tropfenden Wassers kann sich je nach Standort stark unterscheiden. Diese räumliche Variabilität des Bestandsniederschlags ist in tropischen Wäldern höher als in vielen gemäßigten Waldökosystemen, was nicht allein auf verschiedenen Eigenschaften der Ökosysteme zurückzuführen ist. Vielmehr erklären sich die Unterschiede auch aus verschiedenen Waldnutzungen. Abgesehen von biologischen Faktoren beeinflusst die Regenmenge die Variabilität des Bestandsniederschlags erheblich. Die chemische Zusammensetzung des Bestandsniederschlags weist eine noch höhere Variabilität als der Bestandsniederschlag selbst auf. Unterschiede zwischen tropischen und gemäßigten Wäldern lassen sich hier allerdings nicht erkennen, weshalb die hohe Diversität tropischer Ökosysteme die Heterogenität der chemischen Zusammensetzung des Bestandsniederschlags nicht ausreichend erklärt. Eine Vielzahl anderer Faktoren kontrolliert deshalb die Variabilität der Bestandsniederschlagschemie, beispielsweise die Konzentration gelöster Stoffe im Regenwasser oder die Dauer von Trockenperioden. Deren hohe temporale Variabilität ist verantwortlich für die geringe zeitliche Stabilität von Depositionsmessungen. Im Gegensatz dazu ist die temporale Persistenz von Messungen der Bestandsniederschlagsmenge hoch. Insbesondere die Ergebnisse aus Panama zeigen, dass feuchte und trockene Messpunkte über einen Zeitraum von zwei Regenzeiten fortbestehen. Die räumlichen Bestandsniederschlagsmuster im letztgenannten Untersuchungsgebiet sind schwach bzw. weisen die Struktur eines reinen Nugget-Models auf. Die geostatistische Analyse zeigt, dass vor allem die Daten großer Regenereignisse eine robuste Modellierung des Variogramms erfordern, wenn die willkürliche Entfernung von Fernpunkten in den Daten vermieden werden soll. Dieses Resultat ist insbesondere deshalb von Bedeutung, da alle bisherigen Bestandsniederschlagsstudien den klassischen, nicht-robusten Schätzer benutzen, obwohl das Auftreten von Extremwerten in Bestandsniederschlagsdaten für viele Ökosysteme zu erwarten ist.
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Benítez, Juan Manuel González. "Quantification of atmospheric water soluble inorganic and organic nitrogen". Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/4635.
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The key aims of this project were: (i) investigation of atmospheric nitrogen deposition, focused on discrimination between bulk, wet and dry deposition, and between particulate matter and gas phase, (ii) accurate quantification of the contributions of dissolved organic and inorganic nitrogen to each type of deposition, and (iii) exploration of the origin and potential sources of atmospheric water soluble organic nitrogen (WSON). This project was particularly focused on the WSON fraction because, despite it being a potentially important source of bioavailable reactive nitrogen, a number of questions regarding its deposition mechanism (wet vs. dry), composition and origin (natural, anthropogenic or mixed) remain unanswered. There are two major difficulties in WSON determination: (i) the diversity of organic nitrogen compounds compared with the inorganic forms, and (ii) the lack of a direct determination method: the derivation of organic nitrogen concentrations in an aqueous sample involves the determination of the dissolved inorganic nitrogen (DIN) species concentration, comprising nitrate and ammonium, the determination of the total dissolved nitrogen (TDN) concentration, and the subtraction of the DIN concentrations from the TDN concentration. TDN determination requires a preparatory digestion step: high-temperature catalytic oxidation was the method used in this study. Ion chromatography (IC) was the method of choice for nitrate determination, whilst ammonium determination was by IC for rain samples, and by flow injection analysis for air samples collected into aqueous media. This thesis is structured in 3 main parts: the first part examines weekly rain data over a period of 22 months from June 2005 to March 2007 collected in 2 types of rain collector (bulk deposition and “dry+wet” deposition) located in a semi-rural area 15 km southwest of Edinburgh, UK (N55°51′44″, W3°12′19″). Bulk deposition collectors were the standard rain gauges used in the UK national network for monitoring precipitation composition. “Dry+wet” deposition collectors were flushing rain gauges equipped with a rain detector, a spray nozzle, a 2-way valve and two independent bottles to collect funnel washings (dry deposition) and true wet deposition. A key objective in this part of the work was the accurate quantification of inorganic and organic water-soluble nitrogen species contribution to each type of deposition. On average, for the 27 weekly samples with 3 valid replicates for the 2 types of collectors, DON represented 23% of the TDN in bulk deposition. Dry deposition of particles and gas on the funnel surface, rather than rain, contributed over half of all N-containing species (inorganic and organic). Some discrepancies were found between bulk and flushing rain gauges, for deposition of both TDN and DON, suggesting biological conversion and loss of inorganic N in the flushing samplers. The second stage of this project was the investigation of in situ atmospheric concentrations of WSN species, both organic and inorganic. Simultaneous daily measurements of ammonium, nitrate and WSON were made between July and November 2008 at the same semi-rural site in south-east Scotland. Discrimination between material from the gas and particle phases was achieved by means of Cofer scrubbers and PTFE membrane filters, respectively. Average concentrations of NH3 (determined as NH4+), NO2/HNO3 (determined as NO3-) and WSON in the gas phase were 82 ± 54 nmol N m-3, 2.6 ± 2.5 nmol N m-3 and 18 ± 12 nmol N m-3 respectively, and in the particle phase were 20 ± 24 nmol N m-3, 10 ± 9 nmol N m-3 and 8 ± 7 nmol N m-3 respectively (± represent standard deviation across all valid daily samples, not error of triplicate samples). Except for oxidised inorganic N, average concentrations in the gas phase were larger than in the particle phase. No evidence of solely agricultural or solely combustion sources of WSON was found, as no correlation in either phase between WSON and either NH4+ or NO3- could be established. The final stage of this project was to gain a broader picture of nitrogen deposition across Europe. Rain samples were analysed for TDN and DIN from a network of 21 different sampling locations, from the south of Portugal to the north of Finland. The average DON contribution across the 21 sampling sites was ~ 19% and, according to the data gathered in this study, DON species appeared largely unrelated specifically to agricultural or to combustion nitrogen sources, although the results varied widely from site to site. Overall, this work has shown that ON and its deposition comprises a significant component of total atmospheric reactive nitrogen.
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Sweet, Marshall. "Water Soluble Polymer Solar Cells from Electrospray Deposition". VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/3161.
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This dissertation reports the fabrication and characterization of thin films from the water soluble polymer sodium poly[2-(3-thienyl)-ethyloxy-4-butylsulfonate] (PTEBS) by electrospray deposition (ESD). Contiguous thin films were created by adjusting the parameters of the electrospray apparatus and solution properties to maintain a steady Taylor cone for uniform nanoparticle aerosolization and controlling the particle water content to enable coalescence with previously deposited particles. The majority of deposited particles had diameters less than 52 nm. A thin film of 64.7 nm with a root mean square surface roughness of 20.2 nm was achieved after 40 minutes of ESD. Hybrid Solar Cells (HSCs) with PTEBS thin films from spin coating and electrospray deposition (ESD) were fabricated, tested, and modeled. A single device structure of FTO/TiO2/PTEBS/Au was used to study the effects of ESD of the PTEBS layer on device performance. ESD was found to double the short circuit current density (Jsc) by a factor of 2 while decreasing the open circuit voltage (Voc) by half compared to spin coated PTEBS films. Comparable efficiencies of 0.009% were achieved from both device construction types. Current-Voltage curves were modeled using the characteristic solar cell equation showed a similar increase in generated photocurrent with a decrease of two orders of magnitude in the saturation current in devices from ESD films. Increases in Jsc are attributed to increased interfacial contact area between the TiO2 and PTEBS layers, while decreases in Voc are from poor film quality from ESD. Polymer solar cells (PSCs) with water-soluble active layers deposited by ESD were fabricated and tested. The water soluble, bulk heterojunction active layers consisted of PTEBS and the fullerene C60 pyrrolidine tris-acid. A single device structure of ITO/PEDOT:PSS/bulk(PTEBS+C60)/Al was used to study the effect of PTEBS to C60 tris-acid ratio on photovoltaic performance. An active layer ratio of PTEBS:C60 tris-acid (1:2) achieved the highest power conversion efficiency (0.0022%), fill factor (0.25), and open circuit voltage (0.56 V). The percolation threshold of C60 was achieved between 1 part PTEBS and 2 to 3 parts C60. Increasing the C60 tris-acid ratio (1:3) improved short circuit current, but reduced the open circuit voltage enough to lower efficiency.
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Bennett, Jeremy [Verfasser] y Olaf [Akademischer Betreuer] Cirpka. "Applying fluvial depositional concepts in solute transport modelling / Jeremy Bennett ; Betreuer: Olaf Cirpka". Tübingen : Universitätsbibliothek Tübingen, 2018. http://d-nb.info/1168904692/34.
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Karle, Ida-Maja. "On redox reactions and transport processes of solutes in coastal marine sediments /". [Göteborg] : Analystical and Marine Chemistry, Dept. of Chemistry, Göteborg University, 2006. http://www.loc.gov/catdir/toc/fy0706/2006455268.html.
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Koda, Ryo. "Electrochemical deposition of metal on microporous silicon electrodes influenced by hydration structures of solutes and electrode surfaces". 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/199323.
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Casey, Michelle M. "Quantitative Taphonomy of a Triassic Reptile: Tanytrachelos ahynis from the Cow Branch Formation, Dan River Basin, Solite Quarry, Virginia". Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/32503.
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The Virginia Solite Quarry assemblage of Tanytrachelos ahynis, with its exceptionally abundant and uniquely preserved specimens, offers an opportunity to quantify multiple aspects of vertebrate taphonomy. The presence or absence of 128 skeletal elements (i.e., bones) as well as the presence or absence of 136 skeletal variables (i.e., morphometric dimensions) were recorded for 100 specimens collected from two distinct layers within the quarry (lake cycles 2 and 16). Anatomical specimen completeness (or the percent of bones/variables present in a specimen) is low (the median specimen preserves 14.5% of bones and 11.8% of measured variables) in spite of protection from high energy currents, predators, and scavengers afforded by anoxic bottom waters. Specimen size, as approximated by femur length, does not significantly impact specimen completeness. Also, post-exhumation weathering, duration of exposure before burial, and morphotype groupings do not appear to have significantly affected anatomical specimen completeness or articulation. Presence or absence of the enigmatic heterotopic bones represents a true biological signal as indicated by the lack of significant difference in anatomical specimen completeness between the two morphotypes as well as qualitative taphonomic evidence. When anatomical specimen completeness has been corrected for post-depositional faulting, lake cycles 2 and 16 differ from one another significantly in terms of articulation and anatomical completeness of specimens. Specimens with soft-bodied preservation are significantly more articulated, but not significantly more complete, than specimens without preserved soft tissues. Preservation frequency of bones/variables (or the percent of specimens in which a bone/variable is present) varies greatly, but is generally low (an average skeletal element is present in 19% of specimens and an average variable can be measured in 12% of specimens), with significant preferential removal of smaller skeletal elements. Hind limbs, specifically femora, are most commonly preserved. Low anatomical specimen completeness and positive correlation between bone size and frequency of preservation both indicate specimen disturbance by minor hydraulic currents. These taphonomic patterns suggest a moderate-depth depositional environment (slightly shallower than previously proposed).Master of Science
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Zhou, Zhengzhi. "Synthesis of one-dimensional nanostructure materials". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29703.
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Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2009.Committee Chair: Deng,Yulin; Committee Member: Hsieh, Jeffery S.; Committee Member: Nair, Sankar; Committee Member: Singh, Preet; Committee Member: Yao, Donggang. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Morshed, Mahbub. "Study of the separation by organic solvent nanofiltration of diluted solutes using commercial, dense and porous membranes and their derivatives by deposition of polyelectrolyte nanolayers". Thesis, Université de Lorraine, 2019. http://www.theses.fr/2019LORR0089/document.
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L’objectif de cette étude était d’améliorer les performances de séparation OSN de membranes commerciales en vue d’applications en métathèse dans laquelle des catalyseurs hautement dilués sont utilisés. Dans ce travail, des membranes polymères commerciales ont d'abord été étudiée pour caractériser leurs performances dans des milieux organiques en utilisant des mélanges binaires très dilués solute-solvant. Sur la base d'une revue de la littérature, il a été montré que la membrane PERVAP4060, dont le PDMS est la couche active dense était un candidat prometteur pour la nanofiltration milieu organique (OSN). En tant que membrane poreuse, les supports commerciaux AMS et PAN ont également été pris en compte. Dans cette étude, nous avons considéré la modification sur la surface pour conserver les propriétés de matrice polymère. Les multicouches de plasma Ar/O2 et/ou de polyélectrolytes ont été utilisées pour la préparation de membranes prototypes. Les membranes non modifiées et modifiées ont été testées dans des conditions OSN en utilisant des mélanges d'alimentation biniares. Plusieurs solutés très dilués, le ligand organophosphoré R-BINAP, un catalyseur de transfert de phase (ToABR) et des alcanes linéaires ont été étudiés. Le R-BINAP et le ToABR ont tous deux été utilisés dans la plage de 0,0001 à 0,5% en masse et la plupart des expériences ont été réalisées ensuite avec des concentrations de 0,05% en masse de soluté dans le toluène. Il a été montré que le PDMS était capable de retenir 80% de R-BINAP et environ 93% de ToABr dans du toluène. Après modification par les dépôt LBL, le taux de rejet est amélioré avec les membranes modifiées PERVAP4060, conduisant à une rétention de 88% du R-BINAP avec un dépôt de 10 bicouches de polyélectrolytes PAH / PSS en surface, ce taux de rejet pouvant atteindre 95% lorsque le nombre de bicouches est de 20. Le taux de rejet de ToABr augmente à 97%. Les performances de la membrane ont été étudiées sous différentes pressions comprises entre 1 et 40 bars; le haut rejet, encore observé dans ces conditions OSN, plaide résolument en faveur d'un mécanisme de transfert de type solution-diffusion à travers le PDMS. On a également étudié le traitement des mélanges ternaires mimant le mélange catalyseur / solutés / solvant, correspondant à l'hydroformylation ; aucun signe de couplage n’a été détectée et le taux rejet du soluté de masse molaire la plus forte est resté inchangé. D'autre part, l'amélioration du taux de rejet a également observée à partir des membranes poreuses après modification. Le taux de rétention du C44 dans l'AMS a été atteint 75% après modification par 10 bicouches de PDDA / PSS, alors qu’il n'était que de 25% avant modification. Dans le PAN modifié, le taux de rejet des solutés obtenus est dans la plage de 37 à 50%, alors qu’il n'était que de 3 à 7% en masse avant modification. L'inconvénient de la membrane poreuse est toutefois la forte diminution du flux après le dépôt des couches multiplesThe objective of this study was to improve the OSN separation performance of commercial membranes for metathesis applications in which highly diluted catalysts are used. In this work, commercial polymeric membranes were first studied to characterize their performance in organic media using very dilute solute-solvent binary mixtures. Based on a literature review, it was shown that the PERVAP4060 membrane, of which PDMS is the dense active layer, was a promising candidate for organic solvent nanofiltration (OSN). As a porous membrane, the AMS and PAN commercial supports have also been taken into account. In this study, we considered the modification on the surface to improve the separation properties of polymeric OSN membranes. Ar/O2 plasma and/or polyelectrolytes multilayers were used for the preparation of new prototype membranes. Unmodified and modified membranes were tested under OSN conditions using binary feed mixtures. Several highly dilute solutes, organophosphorus ligand R-BINAP, phase transfer catalyst ToABR, and linear alkanes have been studied. Both R-BINAP and ToABR were used in the range of 0.0001 to 0.5% by weight, and most experiments were subsequently performed with 0.05% solute concentrations in toluene. It has been shown that PDMS can retain 80% R-BINAP and about 93% ToABr in toluene. After modification by the LBL deposition, the rejection is improved with the modified PERVAP4060 membranes, leading to an 88% rejection of R-BINAP with a deposit of 10 PAH / PSS polyelectrolyte bilayers at the surface and this rejection being able to reach 95% when the number of bilayers is 20. ToABr rejection increases to 97% with the ten bilayered membranes. The performance of the membrane was studied under different pressures of between 1 and 40 bar; the high rejection, still observed in these OSN conditions, strongly supports a solution-diffusion transfer mechanism through the PDMS. The treatment of ternary mixtures mimicking the catalyst/solute/ solvent mixture corresponding to the hydroformylation has also been studied; no evidence of coupling was detected, and the highest retention remained unchanged. On the other hand, the improvement of the rejection also observed from the porous membranes after modification. The rejection of C44 in the AMS was reached 75% after modification by tention10 bilayers of PDDA / PSS, whereas it was only 25% before modification. In the modified PAN, the rejection of the solutes obtained is in the range of 37 to 50%, whereas it was only 3 to 7% by weight before modification. The disadvantage of the porous membrane, however, is the sharp decrease in flux after the deposition of the multiple layers
Libros sobre el tema "Solute deposition"
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Mitchell, David John. Contemporary and long-term sediment and solute, erosion and deposition of the Wye basin. Birmingham: University of Birmingham, 1990.
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Karle, Ida-Maja. On redox reactions and transport processes of solutes in coastal marine sediments. [Göteborg]: Analystical and Marine Chemistry, Dept. of Chemistry, Göteborg University, 2006.
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Mittal, Sajjan. Amyloidosis. Editado por Patrick Davey y David Sprigings. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780199568741.003.0181.
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Amyloidosis is a multisystem disease caused by the extracellular deposition of insoluble abnormal fibrils that injure tissues and organs. The fibrils are formed by the aggregation of misfolded, normally soluble proteins. Systemic amyloid light-chain (AL) amyloidosis (primary amyloidosis) is the commonest type of amyloidosis in the developed world, accounting for 80% of cases. The remainder are due to AA amyloidosis (secondary or reactive amyloidosis), familial amyloidosis, or other rare types of amyloidosis. The most common clinical features at diagnosis are nephrotic syndrome, heart failure (typically with predominant right heart failure), sensorimotor and/or autonomic peripheral neuropathy, and hepatosplenomegaly.
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Lachmann, Helen J. y Giampaolo Merlini. The patient with amyloidosis. Editado por Giuseppe Remuzzi. Oxford University Press, 2015. http://dx.doi.org/10.1093/med/9780199592548.003.0152.
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Amyloidosis is a disorder of protein folding in which normally soluble plasma proteins are deposited in the extracellular space in an abnormal insoluble fibrillar form. The process of amyloid formation and deposition causes cytotoxicity and progressive organ dysfunction. Amyloid is remarkably diverse and can be hereditary or acquired, localized or systemic, and lethal or merely an incidental finding. The most important numerically are AL amyloidosis, in which the fibrils are composed of monoclonal immunoglobulin light chains, and AA amyloidosis, in which the acute phase reactant Serum Amyloid A component forms the fibrils.The kidney is involved in 75% of patients with systemic amyloidosis. Heavy proteinuria or nephrotic syndrome is characteristic of most amyloid variants.Without treatment, systemic disease is usually fatal but measures that reduce the supply of amyloid fibril precursor proteins can result in regression of amyloid deposits, prevention of organ failure, and improved quality of life and survival. Early diagnosis, before irreversible organ damage has occurred, is the key to effective treatment. Recent advances in diagnosis and therapy have much improved the outlook of patients with AL amyloidosis, but agents with broader promise are under investigation.
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Keenan, Robert T., Sneha Pai y Naomi Schlesinger. Imaging of gout. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199668847.003.0043.
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Gout is a systemic metabolic disease. The enzyme urate oxidase (uricase) that catalyses the oxidation of uric acid to the more soluble compound allantoin is inactive in humans. This may lead to hyperuricaemia. Hyperuricaemia is often present for many years prior to clinical signs of gout. Acute attacks occur as a result of an inflammatory response to monosodium urate (MSU) crystal deposition leading to intense pain and inflammation in the affected joints. Uncontrolled hyperuricaemia and resultant gout can evolve into a destructive arthritis. Imaging may be helpful in the diagnosis of gout as well as in monitoring the response to gout treatment. Plain X-rays are widely used for joint imaging in patients with gout. However, plain X-rays of joints affected by gout are frequently normal, especially early in the disease. In these cases, advanced imaging modalities may be useful. Advanced imaging can help evaluate inflammation, structural joint changes, and magnitude of tophaceous deposits. Advanced imaging modalities include computed tomography (CT), dual-energy CT (DECT), magnetic resonance imaging (MRI), and ultrasound (US). CT may be most suitable to evaluate bone changes in gouty joints and DECT to evaluate tophaceous deposits. MRI may best evaluate soft tissues and Inflammation. US is useful during patients’ visits to the rheumatologist and allows evaluation of cartilage, soft tissues, synovium, and tophaceous deposits. This chapter reviews imaging modalities used in gout patients and discusses their application in the diagnosis and management of gout.
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Badimon, Lina, Felix C. Tanner, Giovanni G. Camici y Gemma Vilahur. Pathophysiology of thrombosis. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780198755777.003.0018.
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Ischaemic heart disease and stroke are major causes of death and morbidity worldwide. Coronary and cerebrovascular events are mainly a consequence of a sudden thrombotic occlusion of the vessel lumen. Arterial thrombosis usually develops on top of a disrupted atherosclerotic plaque because of the exposure of thrombogenic material, such as collagen fibrils and tissue factor (TF), to the flowing blood. TF, either expressed by subendothelial cells, macrophage- and/or vascular smooth muscle-derived foam-cells in atherosclerotic plaques, is a key element in the initiation of thrombosis due to its ability to induce thrombin formation (a potent platelet agonist) and subsequent fibrin deposition at sites of vascular injury. Adhered platelets at the site of injury also play a crucial role in the pathophysiology of atherothrombosis. Platelet surface receptors (mainly glycoproteins) interact with vascular structures and/or Von Willebrand factor triggering platelet activation signalling events, including an increase in intracellular free Ca2+, exposure of a pro-coagulant surface, and secretion of platelet granule content. On top of this, interaction between soluble agonists and platelet G-coupled protein receptors further amplifies the platelet activation response favouring integrin alpha(IIb)beta(3) activation, an essential step for platelet aggregation. Blood-borne TF and microparticles have also been shown to contribute to thrombus formation and propagation. As thrombus evolves different circulating cells (red-blood cells and leukocytes, along with occasional undifferentiated cells) get recruited in a timely dependent manner to the growing thrombus and further entrapped by the formation of a fibrin mesh.
Capítulos de libros sobre el tema "Solute deposition"
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Pirch, N., E. W. Kreutz, B. Ollier y X. He. "The modelling of heat, mass and solute transport in surface processing with laser radiation". En Laser Processing: Surface Treatment and Film Deposition, 177–93. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-009-0197-1_9.
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Matzner, E., T. Zuber y G. Lischeid. "Response of Soil Solution Chemistry and Solute Fluxes to Changing Deposition Rates". En Ecological Studies, 339–60. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-662-06073-5_20.
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Hempenius, Mark A., Mária Péter, Neil S. Robins, E. Stefan Kooij, Rob G. H. Lammertink y G. Julius Vancso. "Water-Soluble Polyferrocenylsilanes for Supramolecular Assemblies by Layer-By-Layer Deposition". En Macromolecules Containing Metal and Metal-Like Elements, 99–114. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2003. http://dx.doi.org/10.1002/0471466573.ch6.
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Özsoy, Türkan. "Atmospheric Wet Deposition of Soluble Macro-Nutrients in the Cilician Basin". En Air Pollution Modeling and Its Application XVI, 609–10. Boston, MA: Springer US, 2004. http://dx.doi.org/10.1007/978-1-4419-8867-6_64.
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van Dijk, Netty, Ian D. Leith, Carole E. R. Pitcairn y Mark A. Sutton. "Soluble Ammonium in Plants as a Bioindicator for Atmospheric Nitrogen Deposition: Refinement and Testing of a Practical Method". En Atmospheric Ammonia, 281–89. Dordrecht: Springer Netherlands, 2009. http://dx.doi.org/10.1007/978-1-4020-9121-6_17.
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"Solute Transport Following Aerosol Deposition in the Lungs". En Inhalation Aerosols, 155–74. CRC Press, 2006. http://dx.doi.org/10.3109/9781420019537-9.
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Tinker, Peter B. y Peter Nye. "Microbiological Modification of the Rhizosphere". En Solute Movement in the Rhizosphere. Oxford University Press, 2000. http://dx.doi.org/10.1093/oso/9780195124927.003.0012.
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The general questions of root/shoot ratio, allocation of carbon to the root system, and root system dynamics are discussed in chapter 9, and the detailed root structure in chapter 5. Root-derived carbon forms the substrate for rhizosphere and symbiotic organisms, and hence leads to the increase in their population densities close to or in the root. Some of the carbon compounds from the root have specific chemical effects also (see chapter 7). Both quantity and composition of these materials need to be known if their effects are to be understood, and we discuss this subject here. The terminology of these materials is rather confused. The collective name for the injection of plant-derived carbon into the soil around living roots is ‘rhizodeposition’, but this has been used in different ways; for example, it may include root-respired carbon dioxide (Whipps 1990), but Darrah (1996) excludes carbon dioxide. The various forms include (Rovira et al. 1979; Lambers 1987; Whipps 1990) solid tissues lost from the root during growth; mucigel and debris from root surfaces and root cap; low-molecular-weight organic compounds in solution; carbon dioxide produced by root respiration for maintenance and for growth; faunal grazing of root tissues; and carbon transferred into symbionts, such as mycorrhizas and rhizobia. Some authors subdivide certain of these classes further. ‘Rhizodeposition’ is loss from a functioning root, but over a longer period the death and decomposition of whole roots deposits large quantities of carbon into the soil, which continues to act as a more resistant microbial substrate (see chapter 9). All of these materials ultimately are converted to carbon dioxide (except for material formed into stable soil organic matter) and this is difficult to separate from carbon dioxide produced directly by root respiration. The main issue here is how the various forms of deposition alter the ability of the living root system to absorb nutrients. We use the following terms for clarity, and because they relate to the practical means whereby these materials are quantified. As the rhizosphere situation is very dynamic, the results obtained will depend upon the timescale considered. (a) Exudates: soluble low-molecular-weight material that comes directly from the living root (microbial metabolites may be similar, but are excluded).
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Abousleiman, Younane y Vinh Nguyen. "PoroChemoElastic Modeling of Wellbore Drilling in Fractured Shale with Solute Transport". En Depositional Processes and Reservoir Characteristics of Siltstones, Mudstones and Shales. SEPM Society for Sedimentary Geology, 2004. http://dx.doi.org/10.2110/sepmmisc.02.0386.
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Pepys, M. B. y P. N. Hawkins. "Amyloidosis". En Oxford Textbook of Medicine, 1766–79. Oxford University Press, 2010. http://dx.doi.org/10.1093/med/9780199204854.003.121203_update_001.
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Amyloidosis is the clinical condition caused by extracellular deposition of amyloid in the tissues. Amyloid deposits are composed of amyloid fibrils, abnormal insoluble protein fibres formed by misfolding of their normally soluble precursors. About 30 different proteins can form clinically or pathologically significant amyloid fibrils in vivo as a result of either acquired or hereditary abnormalities. Small, focal, clinically silent amyloid deposits in the brain, heart, seminal vesicles, and joints are a universal accompaniment of ageing. However, clinically important amyloid deposits usually accumulate progressively, disrupting the structure and function of affected tissues and lead inexorably to organ failure and death. No treatment yet exists which can specifically clear amyloid deposits, but intervention which reduces the availability of the amyloid fibril precursor proteins may lead to amyloid regression with clinical benefit....
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Prashar, Gaurav y Hitesh Vasudev. "Application of Thermal Spraying Techniques Used for the Surface Protection of Boiler Tubes in Power Plants". En Advanced Surface Coating Techniques for Modern Industrial Applications, 112–34. IGI Global, 2021. http://dx.doi.org/10.4018/978-1-7998-4870-7.ch005.
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Distinct methods of depositing the coatings are available according to the intended area of application with a sole objective to protect the surface of structural component like boiler, boiler tubes, and heat exchangers from any mechanical or chemical damage. The main benefit is to minimize the manufacturing cost of a new component and also its fabrication. Thermal spraying is the commonly used technique to tailor the surface properties with a cost-effective approach. The different techniques of thermal spraying such as plasma, HVOF, cold spraying, etc. were investigated and introduced. Although each of these processes has advantages, there are also certain disadvantages associated with them, which limit their application. In the chapter, different methods of depositing coating by thermal spray are discussed and compared. By developing advanced techniques and new coating materials, the life and efficiency of power plants can be enhanced in the future.
Actas de conferencias sobre el tema "Solute deposition"
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Chae, Hyung Min y Jyoti Mazumder. "Numerical modeling of direct metal deposition: Heat transfer/solute transport of ternary system". En ICALEO® 2010: 29th International Congress on Laser Materials Processing, Laser Microprocessing and Nanomanufacturing. Laser Institute of America, 2010. http://dx.doi.org/10.2351/1.5061980.
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Roller, Justin, Radenka Maric, Roberto Neagu y Frank Orfino. "Oxygen Reduction Reaction Evaluation of Platinum Catalysts Formed via the Reactive Spray Deposition Technique". En ASME 2011 9th International Conference on Fuel Cell Science, Engineering and Technology collocated with ASME 2011 5th International Conference on Energy Sustainability. ASMEDC, 2011. http://dx.doi.org/10.1115/fuelcell2011-54278.
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Reactive Spray Deposition Technology (RSDT) is a fabrication process developed for the 1-step deposition of platinum catalyst, carbon support and ionomer directly onto a Nafion® membrane. The process involves pumping a platinum-organic solute dissolved in a combustible solvent through an atomizer. The spray is then combusted and nanosized particles of platinum are produced and subsequently cooled by a gas quench. Once the reaction plume is cooled a secondary set of nozzles is used to inject the carbon support and ionomer. The quench air cools the reactive zone enough to allow direct deposition onto a Nafion® electrolyte or a glassy carbon electrode. This arrangement thus realizes a process for one-step catalyst formation, dispersion onto carbon and direct deposition onto an electrolyte membrane. The independent control of the three components allows for real-time control of the carbon, platinum, and ionomer ratios in the final electrode. In this research work we examine the oxygen reduction reaction via a rotating disc three electrode set-up to understand the intrinsic activity of the as-sprayed platinum. The mass and specific activities were measured in a 0.1 M perchloric acid electrolyte under different deposition conditions and loading was verified by atomic emission spectroscopy inductively coupled plasma (AES-ICP). A range of microscopy images for visualization of the microstructure are also presented. The initial results show that the RSDT technique is capable of producing catalysts with oxygen reduction mass activity at 0.9 V of 200 mA/mgPt rotating at 1600 rpm and 30 °C.
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Ghosh, S. y J. Choi. "Three Dimensional Transient Finite Element Analysis for Microstructure Formation and Residual Stresses in Double-Pass Laser Aided DMD Process". En ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-60196.
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Despite immense advances in Laser Aided Direct Metal/Material Deposition (LADMD) process many issues concerning the effects of process parameters on the stability of variety of properties and the integrity of microstructure have been reported. Modeling of heat flow seems to be a standard practice to couple heat flow calculations to related macroscopic phenomena such as fluid flow in the melt and solid-liquid mushy region, macrosegregation and thermal stresses. A key component in these models is the coupling between thermal and solute fields. Like macrostructural phenomena even microstructural features such as phase appearance, morphology, grain size or spacing are certainly no less important. The focus of this paper is the solute transport, in particular the manner in which process scale transport is coupled to transport at the local scale of the solid-liquid interface which requires a modeling of the redistribution of solutes at the scale of the secondary arm spaces in the dendritic mushy region. Basic microsegregation models which assume either no mass diffusion in the solid (Gulliver-Scheil) or complete diffusion in the solid (equilibrium lever rule) in a fixed arm space are inappropriate in high energy beam processes involving significantly high cooling rates. This paper aims at incorporating a model that accounts for finite mass diffusion and coarsening of the arm space. Due to the complexity and nonlinearity of LADMD process, analytical solutions can rarely address the practical manufacturing process. Consequently, this is an attempt towards a methodology of finite element analysis to predict solidification microstructure and thermal stresses. The simulation has been carried out for H13 tool steel deposited on a mild steel substrate. However, the program can easily be extended to a wide variety of steels.
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Merrill, Marriner H. "Large-Scale Electrospray Ionization Methods for Nanocoating Application". En ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-38799.
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A scalable nano-coating process is needed that can be applied at atmospheric temperatures and pressures with low waste. This would enable the efficient production of advanced thin-film materials from solar cells to super-hydrophobic surfaces. Unfortunately, current methods for producing nanoparticle or nano-structured macromolecular coatings often require substrate immersion, specific atmospheres, and/or long growth times. One potential technique to overcome these challenges would be to use electrospray ionization (ESI) to first disperse large numbers of nanoparticles or polymers in air at standard conditions, and then deposit these on a substrate. ESI is a relatively mature technology, and although it has been developed largely for processing microliter volumes in mass spectrometry, it is believed that the fundamental science can be scaled up. This work presents a model for an ESI deposition method. It combines scaling laws for charged jets with spray and fission models to capture relevant charge, spray, fission, and evaporation phenomena. The developed model is shown to be very simple and efficient while still matching published experimental results. Using the model, current ESI techniques are compared such as NanoESI and Flow-Focusing ESI. A significant technological challenge to ESI deposition is discovered to be the trapping of the majority of the solute in a few primary droplets. Different solutions to this challenge are examined and used to define the direction for future work.
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Saji, Genn. "Degradation of Aged Plants by Corrosion: Radiation-Induced Corrosion Cells Inducing “Long-Cell” Action". En 17th International Conference on Nuclear Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/icone17-75712.
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In the previous papers, the author has established various ‘long cell’ corrosion configurations that should exist in nuclear power plants. With these corrosion mechanisms in place, the plant can be characterized as an assembly of gigantic short-circuited electrical batteries, inducing electrochemical corrosion at localized anodic sites. If these corrosion cells are involved at nuclear power plants, macroscopic electrochemical potential differences must be demonstrated between anodic sites where dissolution of metal (i.e. corrosion) is taking place and cathodic sites where deposition (also called sedimentation) of corrosion products are often observed. Among these, the radiation-induced corrosion cell is an important mechanism of corrosion issues among nuclear power plants, since it plays a major role in the corrosion problems found in primary water, including PWSCC and AOA in PWRs and IGSCC in the BWRs. There is numerous experimental evidence indicating a potential difference induced by radiation, however, the exact mechanism of such phenomena has not been investigated from the ‘long cell action’ corrosion hypothesis point of view. The author investigated the basic mechanism by combining radiation chemistry, electrochemistry and corrosion science to confirm the existence of radiation-induced ‘long-cell’ action (macro) corrosion cell. By performing a competition kinetic study, which is a simplified approach to determine which of several competing reactions will predominate, the hydrated electrons, e−aq, reacting mainly with stable molecules, are found responsible for inducing a large portion of the potential difference both in the PWR and BWR water chemistry environment. The hydrated electrons react with a cathodic half-cell included in the stable solutes thereby inducing redox reactions in the mixed cell configuration with both reducing and oxidizing actions. This method reproduces the reported experimentally observed ECP variation to a certain extent (observed in the INCA Test Loop in Sweden and NRI-Rez BWR-2 Loop in Czech Republic) which was measured by widely changing the solute concentrations, such as dissolved hydrogen and oxygen. The author believes the results support the assumed major reactions acting in the redox process.
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Li, Rongbin, Yaping Li, Danfu Cao, Junfang Wang y Xin Liu. "Experimental Investigation of the Difference in Wax Deposition Aging Rate Between Polyethylene and Steel Pipes". En 2020 13th International Pipeline Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/ipc2020-9332.
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Abstract Wax deposition is an intrinsic problem existing in the production and transportation of waxy crude oil. In the oilfield, non-metallic pipe especially high-density polyethylene pipe (HDPE) has been widely used to solve corrosion problems due to its excellent performance in intensity and corrosion. However, the wax deposition problem in polyethylene (PE) pipe has never been evaluated using dynamic and systemic apparatus. Only a few studies focus on the wax deposition on the coated polyethylene surface by using the cold finger apparatus in recent decades. In this study, the wax deposition experiments were performed using an in-door flow-loop with detachable PE and stainless steel (SS) test sections under the laminar flow regime at the same time to investigate the difference in wax deposition aging rate between the PE and SS pipes. The wax deposits under different operating conditions in both PE and SS pipes were sampled by three layers to study the aging rate at different radial locations during the wax deposition. The wax precipitation characteristics of the wax deposits were determined by using the differential scanning calorimetry (DSC) method. It was found that the wax contents of the wax deposits in PE pipe were lower than that in the SS pipe. And the difference of the wax content between PE pipe and SS pipe decreases with the depositing duration. Eventually, the wax contents of the wax deposits in PE pipe were almost the same as that in the SS pipe. The heat conduction and heat transfer processes in PE pipe and SS pipe were analyzed. The thermal gradient and the concentration gradient at wall were calculated and combined with the heat and mass transfer of wax during the wax deposition to illustrate the difference in wax content. It was found that the variations of the thermal and concentration gradients have significant effects on the diffusion process of wax molecules within the wax deposit layer and thus changing the aging rate. The comparisons and findings of wax deposition between the two kinds of pipes have provided a significant reference for the application of non-metallic pipe in the oilfield.
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Akbar, S. H. y A. A. Saleh. "A Comprehensive Approach To Solve Asphaltene Deposition Problem in Some Deep Wells". En Middle East Oil Show. Society of Petroleum Engineers, 1989. http://dx.doi.org/10.2118/17965-ms.
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Miao, Qing, Jinghua Liang y Baoliang Jiang. "Optimizing the Pigging Frequency Through Prediction of Wax Deposition of Pipeline". En 2006 International Pipeline Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/ipc2006-10265.
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When hot waxy crude oil is pumped into the cold pipeline, the oil temperature will decrease with time and along the pipeline. As soon as the oil temperature near the pipe wall is below the WAP (wax appearance point), the wax contained in the crude will precipitate from the crude and deposit on the inner pipe wall with liquid part entrapped in it. This phenomenon is called wax deposition of the crude oil pipeline. The formation of the wax deposition reduces the throughput of the pipeline but enhances the operation pressure of the pipeline, which brings about more consumption of the power and reduces the safety of the pipeline. More seriously, when the wax deposition layer in the pipeline grows enough thickly, the pipeline would face the danger of shutdown and the enormous loss of economy would occur. So the removal of the wax deposition layer periodically, that is, pigging is strongly needed. Periodic pigging could reduce the operation pressure of the pipeline and keep the throughput of the pipeline, which makes the pipeline avoid hidden trouble of shutdown. Although pigging could solve the problem of the wax deposition of crude oil pipeline successfully, another problem of how to determine the pigging frequency must be faced. Relative to a suitable pigging frequency (though it is difficult to determine), more often pigging could increase the operation cost and wear and tear the inner wall of the pipe but a prolonged interval of pigging may make trouble. Usual means of determining the pigging frequency of a pipeline is mainly based on the pressure drop calculation between two pump stations. From Darcy formula for calculating the pressure loss of the pipeline, the average equivalent inside diameter (say hydraulic inside diameter) of the pipeline could be obtained. Then the average wax deposition thickness in the means of hydraulics could be calculated being based on the original inside diameter of pipeline. According to the average wax deposition thickness and operation experiences, the pigging frequency could be determined. This is true if the wax deposition along the pipeline is almost identical. But in most cases, i.e. to most crude oils and pipelines, the wax deposition profile along the pipeline is not unchanged but a complex curve. In later cases, the average wax deposition thickness calculated from the pressure drop between two pump stations hydraulically exaggerates the average extent of wax deposition but ignores the severity of wax deposition at some local position of pipeline. Thus the pigging frequency determined from the pressure drop might result in more errors, that is, a more frequent pigging or one with more safety troubles. From all the above, a prediction of wax deposition in the pipeline is very necessary and important to the decision of a safe and economic pigging frequency. But due to the complexity of the problem of wax deposition, it is very difficult to predict the wax deposition of one crude oil in a pipeline theoretically. A semi-experience method based on molecular diffusion principle for predicting the wax deposition of Daqing crude oil in the Northeast Pipelines in China is developed and introduced in this paper. Using this method, the wax depositions in the Northeast Pipelines in different seasons are calculated numerically on computers. Based on the calculation results, a more rational pigging scheme aimed at the Northeast Pipelines, which considers the variation of wax deposition along the pipeline, are given.
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Beacham, D. R., O. K. Matar, R. V. Craster, Albert Co, Gary L. Leal, Ralph H. Colby y A. Jeffrey Giacomin. "Advancing Contact Line Dynamics Induced by Soluble Surfactant Deposition on a Thin Liquid Film". En THE XV INTERNATIONAL CONGRESS ON RHEOLOGY: The Society of Rheology 80th Annual Meeting. AIP, 2008. http://dx.doi.org/10.1063/1.2964467.
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Panchagnula, Jayaprakash Sharma y Suryakumar Simhambhatla. "Additive Manufacturing of Complex Shapes Through Weld-Deposition and Feature Based Slicing". En ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-51583.
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Fabricating fully dense and functional metallic components is one of the important challenges in Additive Manufacturing (AM). Additive Manufacturing is a technology in which functional components can be fabricated rapidly and efficiently from their CAD models. It is also referred as Layered Manufacturing (LM) as the object is created by slicing the CAD model into layers and realizing each layer at a time. These layers are thin and stacked or glued together to get the physical shape of the CAD model. However, realizing overhanging features is a difficult task due to deficiency of support mechanism for metals. A separate support structure has to be deposited to build overhanging structures. Although, use of a distinct support material is quite common in non-metallic AM processes, such as Fused Deposition Modelling (FDM), and the same for metals is not yet available. The various techniques in AM process for fabricating metal parts can be mainly classified as laser based, electron beam based and arc based processes. While some Additive Manufacturing processes like Selective Laser Sintering (SLS) employ easily-breakable-scaffolds made of same material to realize the overhanging features, the same approach cannot be extended to deposition processes like laser or arc based direct energy deposition processes. Even though it is possible to realize small overhangs by exploiting the inherent overhanging capability of the process or by blinding some small features like holes, the same cannot be extended for more complex geometries. A different approach to solve this problem is feature based slicing. Unlike uniform and adaptive slicing techniques, where the thickness of a given slice is constant, in feature based slicing inclined slicing; the thickness varies even within a given slice, based on its feature. The current work presents a novel approach for realizing complex overhanging features without the need of support structures. This can be possible by using higher axis kinematics or by adding extra degrees of mobility to the work piece or to the deposition system and suitably aligning the overhang with the deposition direction. Some Vital concepts required in realizing and depositing overhangs are feature based non-uniform slicing and non-uniform area-filling and the same are briefly discussed here. This research will summarize the issues and related approaches in the research, development, and integration. This includes understanding of the weld deposition process by establishing proper geometries, and automated process planning. This technique can be used to fabricate or repair fully dense and functional components for various engineering applications. Although this approach has been implemented for weld-deposition based system, the same can be extended to any other direct energy deposition processes also.