955 resultados para Hetero-coagulation
Resumo:
Seventeen sediment samples of Albian-Cenomanian to early Pliocene age from DSDP Hole 530A in the Angola Basin and six sediment samples of early Pliocene to late Pleistocene age from the Walvis Ridge were investigated by organic geochemical methods, including organic carbon determination, Rock-Eval pyrolysis, gas chromatography and combined gas chromatography/mass spectrometry of extractable hydrocarbons, and kerogen microscopy. The organic matter in all samples is strongly influenced by a terrigenous component from the nearby continent. The amount of marine organic matter present usually increases with the total organic carbon content, which reaches an extreme value of more than 10% in a Cenomanian black shale from Hole 530A. At Site 530 the extent of preservation of organic matter in the deep sea sediments is related to mass transport down the continental slope, whereas the high organic carbon contents in the sediments from Site 532 reflect both high bioproductivity in the Benguela upwelling regime and considerable supply of terrigenous organic matter. The maturation level of the organic matter is low in all samples.
Resumo:
Emiliania huxleyi (strain B 92/11) was exposed to different nutrient supply, CO2 and temperature conditions in phosphorus controlled chemostats to investigate effects on organic carbon exudation and partitioning between the pools of particulate organic carbon (POC) and dissolved organic carbon (DOC). 14C incubation measurements for primary production (PP) and extracellular release (ER) were performed. Chemical analysis included the amount and composition of high molecular weight (>1 kDa) dissolved combined carbohydrates (HMW-dCCHO), particulate combined carbohydrates (pCCHO) and the carbon content of transparent exopolymer particles (TEP-C). Applied CO2 and temperature conditions were 300, 550 and 900 µatm pCO2 at 14 °C, and additionally 900 µatm pCO2 at 18 °C simulating a greenhouse ocean scenario. Enhanced nutrient stress by reducing the dilution rate (D) from D = 0.3 /d to D = 0.1 /d (D = µ) induced the strongest response in E. huxleyi. At µ = 0.3 /d, PP was significantly higher at elevated CO2 and temperature and DO14C production correlated to PO14C production in all treatments, resulting in similar percentages of extracellular release (PER; (DO14C production/PP) × 100) averaging 3.74 ± 0.94%. At µ = 0.1 /d, PO14C production decreased significantly, while exudation of DO14C increased. Thus, indicating a stronger partitioning from the particulate to the dissolved pool. Maximum PER of 16.3 ± 2.3% were observed at µ = 0.1 /d at elevated CO2 and temperature. While cell densities remained constant within each treatment and throughout the experiment, concentrations of HMW-dCCHO, pCCHO and TEP were generally higher under enhanced nutrient stress. At µ= 0.3 /d, pCCHO concentration increased significantly with elevated CO2 and temperature. At µ = 0.1 /d, the contribution (mol % C) of HMW-dCCHO to DOC was lower at elevated CO2 and temperature while pCCHO and TEP concentrations were higher. This was most pronounced under greenhouse conditions. Our findings suggest a stronger transformation of primary produced DOC into POC by coagulation of exudates under nutrient limitation. Our results further imply that elevated CO2 and temperature will increase exudation by E. huxleyi and may affect organic carbon partitioning in the ocean due to an enhanced transfer of HMW-dCCHO to TEP by aggregation processes.
Resumo:
The quantity, type, and maturity of the organic matter in Recent through Upper Jurassic sediments from the Falkland Plateau, DSDP Site 511, have been determined. Sediments were investigated for their hydrocarbon potential by organic carbon and Rock-Eval pyrolysis. Kerogen concentrates were prepared and analyzed in reflected and transmitted light to determine vitrinite reflectance and maceral content. Total extractable organic compounds were analyzed for their elemental composition, and the fraction of the nonaromatic hydrocarbons was determined by capillary column gas chromatography and combined gas chromatography/mass spectrometry. Three main classes of organic matter can be determined at DSDP Site 511 by a qualitative and quantitative evaluation of microscopic and geochemical results. The Upper Jurassic to lower Albian black shales contain high amounts of organic matter of dominantly marine origin. The content of terrigenous organic matter increases at the base of the black shales, whereas the shallowest black shales near the Aptian/Albian boundary are transitional in composition, with increasing amounts of inert, partly oxidized organic matter which is the dominant component in all Albian through Tertiary sediments investigated. The organic matter in the black shales has a low level of maturity and has not yet reached the onset of thermal hydrocarbon generation. This is demonstrated by the low amounts of total extractable organic compounds, low percentages of hydrocarbons, and the pattern and composition of nonaromatic hydrocarbons. The observed reflectance of huminite and vitrinite particles (between 0.4% and 0.5% Ro at bottom-hole depth of 632 m) is consistent with this interpretation. Several geochemical parameters indicate, however, a rapid increase in the maturation of organic matter with depth of burial. This appears to result from the relatively high heat flow observed at Site 511. If we relate the level of maturation of the black shales at the bottom of Hole 511 to their present shallow depth of burial, they appear rather mature. On the basis of comparisons with other sedimentary basins of a known geothermal history, a somewhat higher paleotemperature gradient and/or additional overburden are required to give the observed maturity at shallow depth. A comparison with contemporaneous sediments of DSDP Site 361, Cape Basin, which was the basin adjacent and to the north of the Falkland Plateau during the early stages of the South Atlantic Ocean, demonstrates differences in sedimentological features and in the nature of sedimentary organic matter. We interpret these differences to be the result of the different geological settings for Sites 361 and 511.
Resumo:
Mud volcanism on the Mediterranean Ridge is caused by extrusion of overpressured sediments, with consequent formation of spectacular dome-shaped features composed of mud breccias at the seafloor. The organic material in the mud breccia of the Napoli mud volcano is a mixture of different facies, stratigraphic origin and thermal maturities. One portion is synsedimentary organic material with only minor diagenetic alterations and represents sedimenting material that was embedded into the mud volcano during its extrusion. The mud breccia also contains thermally mature organic material of mainly terrestrial provenance with algae of fresh- and brackish-water origin. Vitrinite reflectance data of this maturity generation range from 0.65 to 0.90% R(oil) and thus characterize thermally mature source rocks, a rank which is corroborated by fluorescence and molecular characteristics. The predominance of vitrinite in the maceral assemblages and the occurrence of biomarkers of terrigenous origin suggest that the major part of the mud matrix derives from a lacustrine or riverine sedimentary unit in the subsurface, possibly from the Messinian stage. A third generation of organic material includes inertinites and vitrinites of high reflectance, which represent recycled organic matter present in any marine sediment. By use of the Lopatin method for modelling the thermal maturation of hydrocarbon source rocks from the vitrinite reflectance data, we calculated that the depth of mobilization ranges from 4900 m to 7500 m, depending upon the temperature gradient used.
Resumo:
Changes in concentration levels and speciation of heavy metals during sedimentation on example of a typical semi-closed bay, where bottom sediments have formed due to river run-off, are under consideration. It is shown that due to desorption of mobile manganese, zinc and copper entered the bay with river suspended matter, their total contents in bottom sediments decrease and percentages of lithogenic forms increase. Contents and speciation of iron in bottom sediments are determined by its participation in coagulation of river colloids in the mixing zone and by mechanical differentiation of sedimentary material.
Resumo:
Changes in concentration levels and speciation of heavy metals during sedimentation on example of a typical semi-closed bay, where bottom sediments have formed due to river run-off, are under consideration. It is shown that due to desorption of mobile manganese, zinc and copper entered the bay with river suspended matter, their total contents in bottom sediments decrease and percentages of lithogenic forms increase. Contents and speciation of iron in bottom sediments are determined by its participation in coagulation of river colloids in the mixing zone and by mechanical differentiation of sedimentary material.
Resumo:
El propósito del estudio fue validar el Inventario de Inteligencia Emocional (SSRI) de Schutte et al. (1998) en una muestra de deportistas españoles de diferente nivel de pericia. Participaron 2091 deportistas (1519 hombres y 572 mujeres) de edades comprendidas entre los 11 y los 59 años (M= 20.8; DT= 6.14). Los resultados de los AFE y AFC mostraron que el cuestionario presenta una estructura de cuatro dimensiones (percepción emocional, gestión auto-emocional, gestión hetero-emocional y utilización emocional), además de permitir obtener un valor de la escala general denominado Inteligencia Emocional en el Deporte. Las propiedades psicométricas y fiabilidad de la escala permiten presentar un inventario apto para la medición de la inteligencia emocional en el deporte.
Resumo:
In the work, the results of an investigation of GaInP/GaInAs/Ge MJ SCs intended for converting concentrated solar radiation, when operating at low temperatures (down to -190 degrees C) are presented. A kink of the cell I-V characteristic has been observed in the region close to V-oc starting from -20 degrees C at operation under concentrated sunlight. The causes for its occurrence have been analyzed and the reasons for formation of a built-in potential barrier for majority charge carriers at the n-GaInP/n-Ge isotype hetero-interface are discussed. The effect of charge carrier transport in n-GaInP/n-p Ge heterostructures on MJ SC output characteristics at low temperatures has been studied including EL technique.
Resumo:
Los procesos de biofiltración por carbón activo biológico se han utilizado desde hace décadas, primeramente en Europa y después en Norte América, sin embargo no hay parámetros de diseño y operación específicos que se puedan utilizar de guía para la biofiltración. Además, el factor coste a la hora de elegir el carbón activo como medio de filtración impacta en el presupuesto, debido al elevado coste de inversión y de regeneración. A la hora de diseñar y operar filtros de carbón activo los requisitos que comúnmente se buscan son eliminar materia orgánica, olor, y sabor de agua. Dentro de la eliminación de materia orgánica se precisa la eliminación necesaria para evitar subproductos en la desinfección no deseados, y reducir los niveles de carbono orgánico disuelto biodegradable y asimilable a valores que consigan la bioestabilidad del agua producto, a fin de evitar recrecimiento de biofilm en las redes de distribución. El ozono se ha utilizado durante años como un oxidante previo a la biofiltración para reducir el olor, sabor, y color del agua, oxidando la materia orgánica convirtiendo los compuestos no biodegradables y lentamente biodegradables en biodegradables, consiguiendo que puedan ser posteriormente eliminados biológicamente en los filtros de carbón activo. Sin embargo la inestabilidad del ozono en el agua hace que se produzcan ácidos carboxilos, alcoholes y aldehídos, conocidos como subproductos de la desinfección. Con esta tesis se pretende dar respuesta principalmente a los siguientes objetivos: análisis de parámetros requeridos para el diseño de los filtros de carbón activo biológicos, necesidades de ozonización previa a la filtración, y comportamiento de la biofiltración en un sistema compuesto de coagulación sobre un filtro de carbón activo biológico. Los resultados obtenidos muestran que la biofiltración es un proceso que encaja perfectamente con los parámetros de diseño de plantas con filtración convencional. Aunque la capacidad de eliminación de materia orgánica se reduce a medida que el filtro se satura y entra en la fase biológica, la biodegradación en esta fase se mantienen estable y perdura a lo lago de los meses sin preocupaciones por la regeneración del carbón. Los valores de carbono orgánico disuelto biodegradable se mantienen por debajo de los marcados en la literatura existente para agua bioestable, lo que hace innecesaria la dosificación de ozono previa a la biofiltración. La adición de la coagulación con la corrección de pH sobre el carbón activo consigue una mejora en la reducción de la materia orgánica, sin afectar a la biodegradación del carbón activo, cumpliendo también con los requerimientos de turbidez a la salida de filtración. Lo que plantea importantes ventajas para el proceso. Granular activated carbon filters have been used for many years to treat and produce drinking water using the adsorption capacity of carbon, replacing it once the carbon lost its adsorption capacity and became saturated. On the other hand, biological activated carbon filters have been studied for decades, firstly in Europe and subsequently in North America, nevertheless are no generally accepted design and operational parameters documented to be used as design guidance for biofiltration. Perhaps this is because of the cost factor; to choose activated carbon as a filtration media requires a significant investment due to the high capital and regeneration costs. When activated carbon filters are typically required it is for the reduction of an organic load, removal of colour, taste and / or odour. In terms of organic matter reduction, the primary aim is to achieve as much removal as possible to reduce or avoid the introduction of disinfection by products, the required removal in biodegradable dissolved organic carbon and assimilable organic carbon to produce a biologically stable potable water which prohibits the regrowth of biofilm in the distribution systems. The ozone has historically been used as an oxidant to reduce colour, taste and odour by oxidizing the organic matter and increasing the biodegradability of the organic matter, enhancing the effectiveness of organic removal in downstream biological activated carbon filters. Unfortunately, ozone is unstable in water and reacts with organic matter producing carboxylic acids, alcohols, and aldehydes, known as disinfection by products. This thesis has the following objectives: determination of the required parameters for the design of the biological activated filters, the requirement of ozonization as a pre-treatment for the biological activated filters, and a performance assessment of biofiltration when coagulation is applied as a pretreatment for biological activated carbon filters. The results show that the process design parameters of biofiltration are compatible with those of conventional filtration. The organic matter removal reduces its effectiveness as soon as the filter is saturated and the biological stage starts, but the biodegradation continues steadily and lasts for a long period of time without the need of carbon regeneration. The removal of the biodegradable dissolved organic carbon is enough to produce a biostable water according to the values shown on the existing literature; therefore ozone is not required prior to the filtration. Furthermore, the addition of coagulant and pH control before the biological activated carbon filter achieves a additional removal of organic matter, without affecting the biodegradation that occurs in the activated carbon whilst also complying with the required turbidity removal.
Resumo:
Esta Tesis Doctoral tiene como principal objetivo el obtener una cadena de tratamientos seguros de aguas seriados que nos permita asegurar la calidad de las aguas para consumo humano en caso de emergencias, de tal forma que se minimicen los efectos de acciones hostiles, como sabotajes o actos terroristas, desastres naturales, etc y buscar soluciones adecuadas para garantizar en este caso la salud. Las plantas de tratamientos de aguas existentes comercialmente no aseguran dicha calidad y la documentación sobre el tema presenta vacíos de conocimiento, contradicciones entre resultados de investigaciones o insostenibilidad de conclusiones de las mismas. Estas carencias nos permiten determinar los aspectos a tratar durante la investigación. Por ello, este objetivo se concretó en tres acciones: Investigar sobre rendimientos de plantas convencionales en eliminación de microorganismos y productos tóxicos y peligrosos. Introducir mejoras que garanticen el rendimiento de las plantas convencionales. Investigar sobre la conveniencia de complementar las instalaciones existentes buscando seguridad y garantía sanitaria. Y se desarrollaron tres líneas de investigación: LI 1 “Inorgánicos”: Investigación sobre la eliminación de los metales boro, cobre y molibdeno mediante procesos de intercambio iónico y de coagulaciónfloculación- decantación. LI 2 “Compuestos Orgánicos Volátiles”: Investigación sobre la eliminación de los compuestos orgánicos 1,1 dicloroetano, 1,2 dicloroetano, clorobenceno, 1,3 dicloropropeno y hexacloro 1,3 butadieno mediante procesos de carbón activo granular y de oxidación avanzada. LI 3 “Plantas portátiles”: Investigación sobre plantas existentes portátiles para verificar su rendimiento teórico y proponer mejoras. Estas líneas de investigación se desarrollaron tanto en el nivel teórico como en el empírico, bien sea en laboratorio como en campo. A lo largo del documento se demuestra que las principales fuentes de contaminación, salvo la degradación de yacimientos naturales, proceden de la actividad humana (efluentes industriales y agrícolas, aguas residuales y actividades beligerantes) que provocan un amplio espectro de enfermedades por lo que dificultan tanto la definición de la fuente como la anticipada detección de la enfermedad. Las principales conclusiones que se obtuvieron están relacionadas con el rendimiento de eliminación de los parámetros tras la aplicación de los procesos y plantas de tratamiento de aguas anteriormente reseñadas. Sin embargo, el verdadero elemento designador de originalidad de esta Tesis Doctoral, tal como se ha reseñado arriba, radica en la definición de un sistema seriado de procesos de tratamiento de aguas que asegura la calidad en caso de emergencia. Éste se define en el siguiente orden: pretratamiento, oxidación, coagulación-floculación-decantación, filtración por arena, intercambio iónico, carbón activo granular, microfiltración, radiación UV, ósmosis inversa, radiación UV y cloración final. The main objective of this Thesis is to obtain a chain of stepwise safe water treatments that allow us to ensure the quality of water for human consumption in case of emergencies, so that the effects of hostile actions, such as sabotage or terrorism, natural disasters, etc. and seek appropriate solutions in this case to ensure health. The existing commercial water treatment plants do not ensure quality, and the documentation on the subject presents knowledge gaps or contradictions. These gaps allow us to determine the issues to be discussed during the investigation. Therefore, this objective was manifested in three actions: Researching yields in commercial plants and microorganisms, or toxic and dangerous products removal. Improvements to ensure the performance of conventional plants. Inquire about the advisability of implementing existing facilities for safety and health guarantee. And three lines of research are developed: LI 1 “Inorganic elements”: Research removing metals iron, copper and molybdenum by ion exchange processes and coagulation-flocculation-decantation. LI 2 “Volatile Organic Compounds”: Research removing organic compounds 1,1 dichloroethane, 1,2 dichloroethane, chlorobenzene, 1,3-dichloropropene and 1,3-butadiene hexachloro through processes of granular activated carbon and advanced oxidation. LI 3 “Compact Water Treatment Plants”: Research on existing packaged plants to verify theoretical performance and suggest improvements. These lines of research are developed both theoretically and empirically, both in the laboratory and in the field. Throughout the document, it is evident that the main sources of pollution, other than the degradation of natural deposits, come from human activity (industrial and agricultural effluents, sewage and belligerent activities) which cause a broad spectrum of diseases which hamper both the definition of the source and the early detection of the disease. The main conclusions drawn are related to both the removal efficiency parameters after application of processes and treatment plants outlined above water. However, the real designator of originality of this thesis, such as outlined above, lies in the definition of a serial system water treatment processes assuring quality in case of emergency. This is defined in the following order: pretreatment, oxidation, coagulation-flocculation-sedimentation, sand filtration, ion exchange, granular activated carbon, microfiltration, UV radiation, reverse osmosis, UV radiation and final chlorination.