981 resultados para continuous flow
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This study aimed to develop, implement and evaluate the performance of a new type of bioreactor for anaerobic treatment of wastewater using different filling materials like trickling filters post-reactor. This bioreactor has mixed characteristics of the UASB reactors and horizontal flow from the point of view of removal of BOD (Biochemical Oxygen Demand) ssed (settled solids), TS (Total Solids), SS (Suspended Solid), SD (Dissolved Solids) and turbidity. The experimental model consists of a bioreactor with a volume of 12 m³, 2/3 filled by fluidized bed and 1/3 for fixed. The fluidized bed is made of polystyrene plates used as a system percolation and compartmentalized trickling filters, where each compartment was filled with a support medium with different characteristics (gravel number 4, plastic rings of polystyrene, PET and HDPE) . In addition, the output of a filter system was installed three entries filled with activated carbon. The bioreactor was installed in private residence in the city of Igarapava-SP (20° 02'40.18"S and 47° 45'01.36" W). The system was highly efficient as the removal of organic contaminant load 92% on average reducing the BOD, a significant result when compared to other anaerobic systems. For the other parameters, the mean reduction was 96% for turbidity, 99% ssed, 67.5% ST, 57% SD and 88% of SS. As for its operation the system was capable of operating in continuous flow without the need for maintenance during the entire period of evaluation and without energy, as it operates taking advantage of the natural slope of the terrain where it is installed. The environmental impacts were minimized due to the preservation of local vegetation allowing the ecosystem to remain unchanged beyond the prototype was completely sealed preventing exhalation of odors and therefore not causing inconvenience to neighboring populations. Given these facts it was concluded that the prototype is shown to be highly feasible deployed as a new alternative for treatment of sewage in rural and urban settings (individual homes, condos, farms, ranches, etc.) Due to ease of design and operability, and sustainability at all stages of execution.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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This study aimed to evaluate the behavior of the deposition and mechanical damage in seeds using a continuous flow metering system under different slope and speed. Part of the study was conducted at Agricultural Research Foundation Agricultural - (FAPA), where seeds that are deposited by a metering system were collected, and the quality analysis verifying the percentage of mechanical damage were conducted at the Faculty of Agricultural Sciences, UNESP, city of Botucatu– SP. The mechanism deposition was subjected to three different speed conditions (4,7, and 10 km.h-1) and three differents working slopes, ( 3%, 8%, and 16%). The results were submitted to Tukey test (p ≤ 0.05), and an analysis of variance with F test at 5% significance level was performed. The results showed an interaction between the factor slope and speed of work, increasing the metering mechanism speed, results in a reduction of the seed deposition at a 3% slope but a working speed of 10 km h-1did not reduce the rate of seed deposition until the slope reaches 16%. Both the slope factor and the working speed caused at least 3.9 and 4.2% more damage to the seeds, respectively.
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Pós-graduação em Agronomia (Energia na Agricultura) - FCA
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Objective: The aim of this study was to screen CO2 laser (10.6 mu m) parameters to increase enamel resistance to a continuous-flow erosive challenge. Background data: A new clinical CO2 laser providing pulses of hundreds of microseconds, a range known to increase tooth acid-resistance, has been introduced in the market. Methods: Different laser parameters were tested in 12 groups (n = 20) with varying fluences from 0.1 to 0.9 J/cm(2), pulse durations from 80 to 400 mu s and repetition rates from 180 to 700 Hz. Non-lased samples (n = 30) served as controls. All samples were eroded by exposure to hydrochloric acid (pH 2.6) under continuous acid flow (60 mu L/min). Calcium and phosphate release into acid was monitored colorimetrically at 30 sec intervals up to 5 min and at 1 min intervals up to a total erosion time of 15 min. Scanning electron microscopic (SEM) analysis was performed in lased samples (n = 3). Data were statistically analysed by one-way ANOVA (p < 0.05) and Dunnett's post-hoc tests. Results: Calcium and phosphate release were significantly reduced by a maximum of 20% over time in samples irradiated with 0.4 J/cm(2) (200 mu s) at 450 Hz. Short-time reduction of calcium loss (<= 1.5 min) could be also achieved by irradiation with 0.7 J/cm(2) (300 mu s) at 200 and 300 Hz. Both parameters revealed surface modification. Conclusions: A set of CO2 laser parameters was found that could significantly reduce enamel mineral loss (20%) under in vitro erosive conditions. However, as all parameters also caused surface cracking, they are not recommended for clinical use.
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ZusammenfassungDie Analyse von Isotopenverhältnissen ist von wachsender Bedeutung bei der Untersuchung von Quellen, Senken und chemischen Reaktionswegen atmosphärischer Spurengase. Distickstoffoxid (N2O) hat vier isotopisch einfach substituierte Spezies: 14N15N16O, 15N14N16O, 14N217O und 14N218O. In der vorliegenden Arbeit wurden massenspektrometrische Methoden entwickelt, die eine komplette Charakterisierung der Variationen im Vorkommen dieser Spezies ermöglichen. Es wird die bisher umfassendste Darstellung dieser Variationen in Troposphäre und Stratosphäre gegeben und mit Bezug auf eine Reihe von Laborexperimenten detailliert interpretiert.Die Laborexperimente machen einen großen Anteil dieser Doktorarbeit aus und konzentrieren sich auf die Isotopenfraktionierung in den stratosphärischen N2O-Senken, d. h. Photolyse und Reaktion mit elektronisch angeregten Sauerstoffatomen, O(1D). Diese Prozesse sind von dominantem Einfluß auf die Isotopenzusammensetzung von atmosphärischem N2O. Potentiell wichtige Parameter wie Temperatur- und Druckvariationen, aber auch Veränderungen der Wellenlänge im Fall der Photolyse wurden berücksichtigt. Photolyse bei stratosphärisch relevanten Wellenlängen > 190 nm zeigte immer Anreicherungen von 15N in beiden Stickstoffatomen des verbleibenden N2O wie auch in 17O und 18O. Die Anreicherungen waren am mittelständigen N-Atom signifikant höher als am endständigen N (mit mittleren Werten für 18O) und stiegen zu größeren Wellenlängen und niedrigeren Temperaturen hin an. Erstmalig wurden für 18O und 15N am endständigen N-Atom Isotopenabreicherungen bei 185 nm-Photolyse festgestellt. Im Gegensatz zur Photolyse waren die Isotopenanreicherungen bei der zweiten wichtigen N2O-Senke, Reaktion mit O(1D) vergleichsweise gering. Jedoch war das positionsabhängige Fraktionierungsmuster dem der Photolyse direkt entgegengesetzt und zeigte größere Anreicherungen am endständigen N-Atom. Demgemäß führen beiden Senkenprozesse zu charakteristischen Isotopensignaturen in stratosphärischem N2O. Weitere N2O-Photolyseexperimente zeigten, daß 15N216O in der Atmosphäre höchstwahrscheinlich mit der statistisch zu erwartenden Häufigkeit vorkommt.Kleine stratosphärische Proben erforderten die Anpassung der massenspektrometrischen Methoden an Permanentflußtechniken, die auch für Messungen an Firnluftproben von zwei antarktischen Stationen verwendet wurden. Das 'Firnluftarchiv' erlaubte es, den gegenwärtigen Trend und die präindustriellen Werte der troposphärischen N2O-Isotopensignatur zu bestimmen. Ein daraus konstruiertes globales N2O-Isotopenbudget ist im Einklang mit den besten Schätzungen der Gesamt-N2O-Emissionen aus Böden und Ozeanen.17O-Messungen bestätigten die Sauerstoffisotopenanomalie in atmosphärischem N2O, zeigten aber auch, daß N2O-Photolyse die Sauerstoffisotope gemäß einem massenabhängigen Fraktionierungsgesetz anreichert. Eine troposphärische Ursache für einen Teil des Exzeß-17O wurde vorgeschlagen, basierend auf der Reaktion von NH2 mit NO2, wodurch die Sauerstoffisotopenanomalie von O3 über NO2 an N2O übertragen wird.
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Hydrothermal fluids are a fundamental resource for understanding and monitoring volcanic and non-volcanic systems. This thesis is focused on the study of hydrothermal system through numerical modeling with the geothermal simulator TOUGH2. Several simulations are presented, and geophysical and geochemical observables, arising from fluids circulation, are analyzed in detail throughout the thesis. In a volcanic setting, fluids feeding fumaroles and hot spring may play a key role in the hazard evaluation. The evolution of the fluids circulation is caused by a strong interaction between magmatic and hydrothermal systems. A simultaneous analysis of different geophysical and geochemical observables is a sound approach for interpreting monitored data and to infer a consistent conceptual model. Analyzed observables are ground displacement, gravity changes, electrical conductivity, amount, composition and temperature of the emitted gases at surface, and extent of degassing area. Results highlight the different temporal response of the considered observables, as well as the different radial pattern of variation. However, magnitude, temporal response and radial pattern of these signals depend not only on the evolution of fluid circulation, but a main role is played by the considered rock properties. Numerical simulations highlight differences that arise from the assumption of different permeabilities, for both homogeneous and heterogeneous systems. Rock properties affect hydrothermal fluid circulation, controlling both the range of variation and the temporal evolution of the observable signals. Low temperature fumaroles and low discharge rate may be affected by atmospheric conditions. Detailed parametric simulations were performed, aimed to understand the effects of system properties, such as permeability and gas reservoir overpressure, on diffuse degassing when air temperature and barometric pressure changes are applied to the ground surface. Hydrothermal circulation, however, is not only a characteristic of volcanic system. Hot fluids may be involved in several mankind problems, such as studies on geothermal engineering, nuclear waste propagation in porous medium, and Geological Carbon Sequestration (GCS). The current concept for large-scale GCS is the direct injection of supercritical carbon dioxide into deep geological formations which typically contain brine. Upward displacement of such brine from deep reservoirs driven by pressure increases resulting from carbon dioxide injection may occur through abandoned wells, permeable faults or permeable channels. Brine intrusion into aquifers may degrade groundwater resources. Numerical results show that pressure rise drives dense water up to the conduits, and does not necessarily result in continuous flow. Rather, overpressure leads to new hydrostatic equilibrium if fluids are initially density stratified. If warm and salty fluid does not cool passing through the conduit, an oscillatory solution is then possible. Parameter studies delineate steady-state (static) and oscillatory solutions.
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Chlorinated Aliphatic Hydrocarbons (CAHs) are widespread wastewater and groundwater contaminants and represent a real danger for human health and environment. This research is related to the biodegradation technologies to treat chlorinated hydrocarbons. In particular the study of this thesis is focused on chloroform cometabolism by a butane-grown aerobic pure culture (Rhodococcus aetherovorans BCP1) in continuous-flow biofilm reactors, which are used for in-situ and on-site treatments. The work was divided in two parts: in the first one an experimental study has been conducted in two packed-bed reactors (PBRs) for a period of 370 days; in the second one a fluid dynamics and kinetic model has been developed in order to simulate the experimental data concerning a previous study made in a 2-m continuous-flow sand-filled reactor. The goals of the first study were to obtain preliminary information on the feasibility of chloroform biodegradation by BCP1 under attached-cell conditions and to evaluate the applicability of the pulsed injection of growth substrate and oxygen to biofilm reactors. The pulsed feeding represents a tool to control the clogging and to ensure a long bioreactive zone. The operational conditions implemented in the PBRs allowed the attainment of a 4-fold increase of the ratio of chloroform degraded to substrate consumed, in comparison with the phase of continuous substrate supply. The second study was aimed at identifying guidelines for optimizing the oxygen/substrate supply schedule, developing a reliable model of chloroform cometabolism in porous media. The tested model led to a suitable interpretation of the experimental data as long as the ratio of CF degraded to butane consumed was ≤ 0.27 mgchloroform /mgbutane. A long-term simulation of the best-performing schedule of pulsed oxygen/substrate supply indicated the attainment of a steady state condition characterized by unsatisfactory bioremediation performances, evidencing the need for a further optimization of the pulsed injection technique.
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Ein neu konstruierter Kondensationskernzähler COPAS (COndensation PArticle counting System) für in-situ-Messungen der Konzentration von Aitken-Teilchen und ultrafeinen Aerosolpartikeln wurde im Rahmen dieser Arbeit erstmals erfolgreich bei Flugzeugmessungen eingesetzt. COPAS ist ein für flugzeuggestützte Messungen an Bord des Forschungsflugzeuges „Geophysica“ in der oberen Troposphäre und unteren Stratosphäre angepaßtes und voll automatisiertes System. Die Verfahrensweise, die Aerosolpartikel des Größenbereichs mit Durchmessern d < 100 nm zum Anwachsen zu bringen, um sie mittels optischer Detektion zu erfassen, ist im COPAS durch das Prinzip der thermischen Diffusion realisiert, wodurch eine kontinuierliche Messung der Aerosolkonzentration mit der untersten Nachweisgrenze für Partikeldurchmesser von d = 6 nm gewährleistet ist. Durch die Verwendung einer Aerosolheizung ist die Unterscheidung von volatilem und nichtvolatilem Anteil des Aerosols mit COPAS möglich. In umfassenden Laborversuchen wurde das COPAS-System hinsichtlich der unteren Nachweisgrenze in Abhängigkeit von der Betriebstemperatur und bei verschiedenen Druckbedingungen charakterisiert sowie die Effizienz der Aerosolheizung bestimmt. Flugzeuggestützte Messungen fanden in mittleren und polaren Breiten im Rahmen des EUPLEX-/ENVISAT-Validierungs–Projektes und in den Tropen während der TROCCINOX/ENVISAT-Kampagne statt. Die Messungen der vertikalen Konzentrationsverteilung des Aerosols ergaben in polaren Breiten eine Zunahme der Konzentration oberhalb von 17 km innerhalb des polaren Vortex mit hohem Anteil nichtvolatiler Partikel von bis zu 70 %. Als Ursache hierfür wird der Eintrag von meteoritischen Rauchpartikeln aus der Mesosphäre in die obere und mittlere Stratosphäre des Vortex angesehen. Ferner konnte in der unteren Stratosphäre des polaren Vortex der Einfluß troposphärischer Luft aus niedrigen Breiten festgestellt werden, die sich in einer hohen Variabilität der Aerosolpartikelkonzentration manifestiert. In tropischen Breiten wurde die Tropopausenregion untersucht. Dabei wurden Konzentrationen von bis zu 104 ultrafeiner Aerosolpartikel mit 6 nm < d < 14 nm pro cm-3 Luft gemessen, deren hoher volatiler Anteil einen sicheren Hinweis darauf gibt, daß die Partikel durch den Prozeß der homogenen Nukleation gebildet wurden. Damit konnte erstmals die Schlußfolgerungen von Brock et al. (1995) durch direkte Messungen der ultrafeinen Partikelkonzentration weitergehend belegt werden, daß in der tropischen Tropopausenregion die Neubildung von Aerosolpartikeln durch homogene Nukleation stattfindet. Die vertikalen Verteilungen der stratosphärischen Aerosolpartikelkonzentration mittlerer Breiten verdeutlichen die Ausbildung einer über 6 Jahre hinweg nahezu konstanten Hintergrundkonzentration des stratosphärischen Aerosols unter vulkanisch unbeeinflußten Bedingungen. Ferner gibt die vergleichende Untersuchung der stratosphärischen Aerosolpartikelkonzentration aus polaren, mittleren und tropischen Breiten Aufschluß über den Transport und die Prozessierung des stratosphärischen Aerosols und insbesondere über den Austausch von Luftmassen zwischen der Stratosphäre und der Troposphäre.
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Atmospheric aerosol particles serving as cloud condensation nuclei (CCN) are key elements of the hydrological cycle and climate. Knowledge of the spatial and temporal distribution of CCN in the atmosphere is essential to understand and describe the effects of aerosols in meteorological models. In this study, CCN properties were measured in polluted and pristine air of different continental regions, and the results were parameterized for efficient prediction of CCN concentrations.The continuous-flow CCN counter used for size-resolved measurements of CCN efficiency spectra (activation curves) was calibrated with ammonium sulfate and sodium chloride aerosols for a wide range of water vapor supersaturations (S=0.068% to 1.27%). A comprehensive uncertainty analysis showed that the instrument calibration depends strongly on the applied particle generation techniques, Köhler model calculations, and water activity parameterizations (relative deviations in S up to 25%). Laboratory experiments and a comparison with other CCN instruments confirmed the high accuracy and precision of the calibration and measurement procedures developed and applied in this study.The mean CCN number concentrations (NCCN,S) observed in polluted mega-city air and biomass burning smoke (Beijing and Pearl River Delta, China) ranged from 1000 cm−3 at S=0.068% to 16 000 cm−3 at S=1.27%, which is about two orders of magnitude higher than in pristine air at remote continental sites (Swiss Alps, Amazonian rainforest). Effective average hygroscopicity parameters, κ, describing the influence of chemical composition on the CCN activity of aerosol particles were derived from the measurement data. They varied in the range of 0.3±0.2, were size-dependent, and could be parameterized as a function of organic and inorganic aerosol mass fraction. At low S (≤0.27%), substantial portions of externally mixed CCN-inactive particles with much lower hygroscopicity were observed in polluted air (fresh soot particles with κ≈0.01). Thus, the aerosol particle mixing state needs to be known for highly accurate predictions of NCCN,S. Nevertheless, the observed CCN number concentrations could be efficiently approximated using measured aerosol particle number size distributions and a simple κ-Köhler model with a single proxy for the effective average particle hygroscopicity. The relative deviations between observations and model predictions were on average less than 20% when a constant average value of κ=0.3 was used in conjunction with variable size distribution data. With a constant average size distribution, however, the deviations increased up to 100% and more. The measurement and model results demonstrate that the aerosol particle number and size are the major predictors for the variability of the CCN concentration in continental boundary layer air, followed by particle composition and hygroscopicity as relatively minor modulators. Depending on the required and applicable level of detail, the measurement results and parameterizations presented in this study can be directly implemented in detailed process models as well as in large-scale atmospheric and climate models for efficient description of the CCN activity of atmospheric aerosols.
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The main objective of this research is to improve the comprehension of the processes controlling the formation of caves and karst-like morphologies in quartz-rich lithologies (more than 90% quartz), like quartz-sandstones and metamorphic quartzites. In the scientific community the processes actually most retained to be responsible of these formations are explained in the “Arenisation Theory”. This implies a slow but pervasive dissolution of the quartz grain/mineral boundaries increasing the general porosity until the rock becomes incohesive and can be easily eroded by running waters. The loose sands produced by the weathering processes are then evacuated to the surface through processes of piping due to the infiltration of waters from the fracture network or the bedding planes. To deal with these problems we adopted a multidisciplinary approach through the exploration and the study of several cave systems in different tepuis. The first step was to build a theoretical model of the arenisation process, considering the most recent knowledge about the dissolution kinetics of quartz, the intergranular/grain boundaries diffusion processes, the primary diffusion porosity, in the simplified conditions of an open fracture crossed by a continuous flow of undersatured water. The results of the model were then compared with the world’s widest dataset (more than 150 analyses) of water geochemistry collected till now on the tepui, in superficial and cave settings. All these studies allowed verifying the importance and the effectiveness of the arenisation process that is confirmed to be the main process responsible of the primary formation of these caves and of the karst-like superficial morphologies. The numerical modelling and the field observations allowed evaluating a possible age of the cave systems around 20-30 million of years.
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Zur Entwicklung einer selektiven Tumorimmuntherapie wurden im Rahmen dieser Dissertation potentielle Vakzine dargestellt. Als Leitstruktur für die Impfstoffkandidaten diente das Oberflächenglycoprotein MUC1, das durch fehlregulierte Enzymaktivitäten auf malignen Zellen strukturell verändert überexprimiert wird. Hierbei wurde insbesondere der Einfluss von Fluorsubstituenten in der Glycanseitenkette auf die Immunogenität und die Spezifität der Vakzine untersucht. Dazu wurde ein dreifach fluoriertes Analogon an Tetanus Toxoid (TTox) als Trägerprotein angebunden und in Immunisierungsstudien an transgenen Mäusen konnten hohe Selektivitäten und starke Immunantworten nachgewiesen werden. Die Darstellung des 20 Aminosäuren umfassenden Glycopeptides erfolgte an der festen Phase, wobei unterschiedlich fluorierte Thomsen-Friedenreich-Antigenanaloga anstelle eines Threonins in die Sequenz eingebaut wurden. Diese Bausteine wurden durch Glycosylierungsreaktionen fluorierter Donoren sowie Akzeptoren hergestellt, wobei Letztere durch nachträgliche Fluorierungen der Glycosylaminosäure erhalten wurden. Darüber hinaus wurde die Durchführung der komplexen Glycosylierungsreaktionen in Mikroreaktoren am Beispiel zweier fluorierter Glycosylaminosäuren untersucht. Neben der raschen Optimierung der Reaktionsparameter in Durchflussreaktoren konnte die direkte Umsetzung in einem mikrostrukturierten Reaktor in den präparativen Maßstab demonstriert werden.