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Doppler optical coherence tomography in determination of suspension viscosityLauri, J. (Janne) 17 September 2013 (has links)
Abstract
Doppler optical coherence tomography (DOCT) provides a non-disruptive, high resolution and real-time method for imaging flow velocity profiles inside small channels and capillaries. DOCT has been mostly used in the biomedical field to image blood flow. However, applications in the field of rheology have been rare.
In this thesis, the time domain DOCT (TD-DOCT) was utilized to measure flow velocity profiles inside capillaries with high resolution. Time domain configuration was chosen due to the ability to implement dynamic focusing and, in addition, to have sufficient velocity range, especially at high speeds. The accuracy and reliability of the laboratory-built DOCT device was verified with Newtonian suspension and, further, the performance was compared to the commercial DOCT. In vivo measurements with slime mould Physarum polycephalum showed the versatility of DOCT to measure the flow velocity profile of a different kind of scattering suspension even with very low flow rates.
The effects of multiple scattering on the accuracy of the measured flow velocity profiles were experimentally studied with two phantom configurations. The first case consisted of the static superficial layer, where the plain glass capillary with flowing Intralipid suspension was embedded into a cuvette. In the second case the moving superficial layer was made by introducing a second glass capillary in front of the studied flow. The results showed that multiple scattering has noticeable effect on the accuracy of the measured flow velocity profiles, especially at the deeper regions.
Novel application of the DOCT technique is presented by implementing it to a capillary viscometer. As a result, the absolute viscosity of the Newtonian suspension is derived with high precision directly from the measured flow velocity profile and pressure drop without making any assumption of the flow under study. The results are consistent with the reference values measured with the commercial viscometer. / Tiivistelmä
Doppler optinen koherenssitomografia (DOCT) on tekniikka, jolla on mahdollista mitata suspensioiden virtausnopeusprofiili virtausta häiritsemättömästi, reaaliaikaisesti ja tarkalla resoluutiolla ohuista kapillaareista. DOCT-tekniikkaa on hyödynnetty erityisesti lääketieteen alueella silmän rakenteen kuvantamisessa ja veren virtausmittauksissa. Tekniikan sovellukset nesteiden reologian tutkimuksessa ovat olleet harvinaisia. Tämän työn tarkoituksena on kehittää DOCT-tekniikkaa ja soveltaa sitä kapillaariviskometrissä viskositeetin määritykseen suoraan mitatusta virtausnopeusprofiilista.
Tässä työssä hyödynnettiin laboratoriossa rakennettua aikatason DOCT-laitetta (TD-DOCT), jolla mitattiin virtausnopeusprofiili kapillaarin sisältä mikrometrien resoluutiolla. TD-DOCT valittiin, koska siinä voitiin käyttää dynaamista fokusointia parantamaan sivusuuntaista resoluutiota ja signaali-kohinasuhdetta. Tämän lisäksi se soveltuu laaja-alaisesti eri virtausnopeuksille, erityisesti nopeille virtauksille. Rakennetun DOCT-laitteen tarkkuus ja luotettavuus todennettiin mittaamalla Newtonista suspensiota ja vertaamalla mittaustuloksia kaupallisella DOCT:lla tehtyihin mittauksiin. Mittaukset elävässä organismissa, Physarum polycephalum -limasienessä, osoittavat laitteen soveltuvuuden erilaisten suspensioiden virtausnopeusprofiilin mittaukseen myös hyvin hitaissa virtauksissa.
Moninkertaisen sironnan vaikutusta mitattujen profiilien tarkkuuteen tutkittiin kahdella eri konfiguraatiolla. Ensimmäisessä asetelmassa virtausnopeusprofiili mitattiin kapillaarista, joka oli upotettu valoa sirottavaan Intralipid-suspensioon, ja jonka upotussyvyyttä voitiin säätää. Toisessa asetelmassa muodostettiin dynaaminen valoa sirottava kerros asettamalla toinen Intralipidiä sisältävä kapillaari mitattavan kapillaarin eteen. Tulokset osoittavat, että monikertainen sironta vaikuttaa mitatun virtausnopeusprofiilin tarkkuuteen erityisesti kun valoa sirottava kerroksen paksuus kasvaa.
Tässä työssä DOCT -tekniikkaa käytetään ensimmäistä kertaa kapillaariviskometrin yhteydessä. Newtonisen suspension absoluuttinen viskositeetti määritetään hyvin tarkasti suoraan mitatusta virtausnopeusprofiilista ja painehäviöstä ilman oletuksia virtaavasta nesteestä. Mitatut viskositeettiarvot vastaavat vertailumittauksia, jotka tehtiin kaupallisella rotaatioviskosimetrilla.
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A Hydrological Framework for Geo-referenced Steady-State Exposure Assessment in Surface Water on the Catchment ScaleWissing, Jutta 30 September 2010 (has links)
The major benefit of geo-referenced exposure modelling tools is the provision of spatially distributed information on expected environmental concentrations. This allows for identifying local and regional concentration differences in the environment which facilitates the development of efficient mitigation strategies. Predicted substance concentrations in the environment are governed by emission rates and representation of the substances' transport and transformation processes on the one hand and by the description of the spatial environmental heterogeneity and temporal variability on the other hand.
The shape of river basins and streamflow variability within them is a product of physiographic and climatic factors like e. g. topography, land use, precipitation, or evapotranspiration. These factors are very variable in space and time. This heterogeneity in river basins may have an impact on surface water concentrations of various substances.
In this work a hydrological framework for geo-referenced exposure assessment in river networks has been developed which predominantly addresses spatial heterogeneity of river basins.
The theoretical background for parameterising a river network for the application of GREAT-ER (Geo-referenced Regional Exposure Assessment Tool for European Rivers) is elaborated and implemented.
Quantity of discharge, flow velocity of river water and depth of river bed have to be determined at any location in a river network for the representation of substance dilution, transport and degradation. Temporal variability is handled by a probabilistic approach which demands choice and parameterisation of probability distribution functions to describe the river network characteristics.
It is substantiated that discharge and its variation can be described by a lognormal probability distribution. This distribution can be parameterised by spatially distributed information on effective precipitation and specific low flow discharge from the German Hydrological Atlas. Geoprocessing methods are applied to couple information from these maps and the river network. Evaluation of discharge probability distributions by means of gauging data demonstrates good agreement.
River depth and flow velocity are estimated on the basis of spatially distributed river structure data and therefore account for actual river morphology more than former approaches do. A comparison with hitherto used flow velocity and depth estimation shows significant differences which trigger perceivable differences in surface water concentration estimates.
Identification of the sensitivity of hydrological parameters in terms of chemical fate estimation attaches importance to spatial explicit consideration of river networks. The main benefit of the presented methods is comprehensive incorporation of geo-referenced river basin characteristics into the data basis for the GREAT-ER model because this provides the basis for successful prediction of surface water concentrations by GREAT-ER.
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An optical sensor for in-stream monitoring of suspended sediment concentrationZhang, Yali January 1900 (has links)
Doctor of Philosophy / Department of Biological & Agricultural Engineering / Naiqian Zhang / Suspended sediment concentration (SSC) in water is one of the most important parameters to evaluate water quality. Monitoring SSC provides important information on determining sediment transport for soil erosion research and soil/water conservation practices. Sediment mass transported at a given time can be assessed by simultaneous SSC and water flow velocity measurements. Fouling, including bio-fouling, has damaging impact on optical SSC measurements over the long term. In this study, an inexpensive, real-time, self-cleaning, optical sediment and flow velocity sensor was developed.
Laboratory experiments were conducted on a previously designed SSC sensor. A light modulation algorithm was designed to reduce the influence of ambient light, especially sunlight, on measurement accuracy. Statistical models to predict SSC based on measured light intensities were established and compared with neural network models. The statistical analysis showed that soil texture played an important role in SSC measurement accuracy while the designed sensor was capable of reducing the effect of water color on sensor performance. Neural-network models can further remove the influence of soil texture type on SSC measurement. The sensor design was simplified based on a stepwise selection analysis.
Long-term field experiments were conducted in Kansas and Georgia to evaluate the sensor performance, the effect of fouling, including bio-fouling, on sensor lenses, and the effect of temperature on the measurement. Methods of removing the fouling effect through data correction were developed. Results indicated that the designed optical SSC sensor was capable of providing rapid response to SSC fluctuations in water flow. Temperature of the water body has an insignificant impact on SSC measurement.
In order to reduce fouling, an air-blast cleaning mechanism was integrated into the optical sediment sensor. Laboratory experiments in a manually created fouling environment were conducted to observe the fouling process on sensor cases made of different materials, and to verify the effectiveness of air-blast cleaning in reducing fouling. Results indicated that air-blast cleaning mechanism was capable of reducing clay/silt fouling on sensor signals. The duration and frequency of air-blast cleaning can be determined and adjusted depending on actual field conditions. An air pressure drop test was conducted on the hose carrying pressurized air. Results showed negligible pressure drop.A flow velocity measurement function based on the cross-correlation principle was integrated into the optical sediment sensor. An experiment was conducted in laboratory to examine the sensor performance on velocity measurement using a closed circulation system. A solution of blue colorant, Brilliant Blue FCF, was used as an artificial source to absorb light emitted by LEDs in the sensor and the signal variation patterns were measured. The results indicated that the cross-correlation-based velocity sensor was capable of measuring water flow velocity within in a certain velocity range using the dye injection method.
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Flussgeschwindigkeiten von Leukozyten über EndothelzellmonolayerThanabalasingam, Usan 17 May 2004 (has links)
Das Ziel dieser Arbeit war die Untersuchung der Rollgeschwindigkeiten von Leukozyten auf humanen kardialen mikrovaskulären Endothelzellen (HCMEC) und humanen umbilikalen venösen Endothelzellen (HUVEC). Die Endothelzellen wurden aus explantierten humanen Herzen sowie aus menschlichen Nabelschnüren unmittelbar postpartal gewonnen. Unter definierten Bedingungen wurden die in einer Flusskammer gemessenen Geschwindigkeiten von L-Selektin exprimierenden Nalm6-IF4 Zellen auf unstimulierten Endothelzellen mit denen auf stimulierten Endothelzellen verglichen. Die langsamere Geschwindigkeit der Leukozyten auf stimulierten Endothelzellen weist darauf hin, dass L-Selektin Liganden auf humanen kardialen mikrovaskulären Endothelzellen erst nach Stimulation exprimiert werden. Die beobachtete Geschwindigkeitsreduktion der Leukozyten ist jedoch von dem in der Literatur beschriebenen Selektin vermittelten Rollen zu unterscheiden. In den Versuchen mit Tunicamycin wurde gezeigt, dass N-glykosidisch gebundene Zucker kritische Bestandteile der Liganden für ihre Interaktion mit L-Selektin sind. Unter den gleichen Versuchsbedingungen wurde auch der Einfluss E-Selektin vermittelter Interaktionen auf die Geschwindigkeit der HL60 Zellen untersucht. Neben dem typischen Rollen wurde hier ebenfalls eine Selektin abhängige Geschwindigkeitsreduktion gesehen. / The aim of the present study was to investigate selectin mediated rolling velocities of leucocytes on human cardiac microvascular endothelial cells (HCMEC) and human umbilical vein endothelial cells (HUVEC). HCMEC were gained from explanted human hearts and HUVEC from umbilical cords immediately postpartum. Flow velocities of L-Selectin expressing Nalm6-IF4 cells on quiesent endothelial cells were compared to those on stimulated endothelial cells. Stimulation of endothelial cells with TNF led to significantly slower velocities of Nalm6-IF4 cells indicating that HCMEC express L-Selectin ligands only after stimulation. The observed reduction of flow velocities differs from rolling of leucocytes described in the literature. Experiments with tunicamycin showed that N-glycosylated carbohydtrate moieties are needed for proper function of L-Selectin ligands. E-Selectin mediated interactions between HL60 cells and endothelial cells were studied under the same conditions. Besides the typical rolling, a selectin mediated reduction of flow velocity was observed.
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The influence of macrozoobenthos in lake sediments on hydrodynamic transport processes and biogeochemical impactsRoskosch, Andrea 12 December 2011 (has links)
Ziel dieser Dissertation ist, Wissensdefizite im Bereich der Bioirrigation von Süßwassersedimenten abzubauen. Als Untersuchungsorganismus wurde Chironomus plumosus ausgewählt weil diese weit verbreitete Larve ihre U-förmigen Röhren mit Überstandswasser durchspült und so Nahrung aus dem Wasser filtriert. Um Bioirrigation in Wohnröhren mit einem Durchmesser von ca. 1,7 mm zu untersuchen, wurden geeignete Messmethoden entwickelt, mit denen für das 4. Larvenstadium die Parameter Fließgeschwindigkeit (14,9 mm/s), Pumpzeit (33 min/h) und Pumprate (61 ml/h) gemessen wurden. Bei einer Populationsdichte von 745 Larven/m2 kann somit ein Wasservolumen äquivalent zum Volumen des Müggelsee in Berlin, innerhalb von 5 Tagen durch das Sediment gepumpt werden. Die Positronen-Emissions-Tomographie wurde für die Sedimentanalytik adaptiert und der Transport im Porenwasser analysiert. Mit den Untersuchungen wure gezeigt, dass auch in schlammigen Seesedimenten ein advektiver Transport durch Bioirrigation verursacht wird, der nicht zu vernachlässigen ist. Steigende Temperaturen resultieren aufgrund steigender Fließgeschwindigkeit in einen signifikanten Anstieg der Pumprate sowie der Eintragsrate von Überstandswasser ins Sediment. Ein abfallender Sauerstoffgehalt verlängert die Pumpzeit und führt zu einer sinkenden Fließgeschwindigkeit. Außerdem wird aus den Untersuchungen eine jahreszeitliche Variabilität der Bioirrigation sichtbar, welche unabhängig von konstanten Laborbedingungen auftritt. Mit dem Wasserstrom werden Porenwasserspezies wie SRP in den Wasserkörper abtransportiert, wohingegen SO42- und O2 aus dem Überstandswasser in das Sediment eingetragen werden. Ferner kommt es zur Oxidation von Fe2+ infolgedessen Phosphat im Sediment festgelegt wird, wie mittels P-Fraktionierung gezeigt werden konnte. Mikrobiologische Untersuchungen zeigten, dass Bioirrigation die mikrobielle Abundanz steigert, die Bakteriengemeinschaft verändert und das Potential zur enzymatischen Hydrolyse erhöht. / The aim of this thesis is to fill gaps of knowledge regarding bioirrigation in freshwater sediments. Chironomus plumosus was chosen for the investigations since the filter-feeding larva dwelling in U-shaped burrows is quite common and flushes its burrow with water from the overlying water body. To investigate bioirrigation activity in burrows of approximately 1.7 mm in diameter appropriate measurement techniques were developed. With the methods several parameters were measured for 4th stage of larvae: flow velocity (14.9 mm s-1), pumping time (33 min h-1), and pumping rate (61 ml h-1). Consequently, a water volume equivalent to the volume of Lake Müggelsee in Berlin is pumped through the sediment every 5 days by a population density of 745 larvae m-2. The nuclear medicine imaging technique Positron Emissions Tomography was adapted and used to analyze the transport in the sediment pore water. By means of the experiments, it could be shown that even in muddy lake sediments advection is a relevant transport process and should not be neglected. Rising temperatures result in increased pumping rates and increased influx rates of surface water into the sediment due to increased flow velocities in the burrows. Dropping oxygen concentrations prolong the pumping duration while the flow velocity decreases. Furthermore, experiments show a seasonal variability of bioirrigation which is independent of constant laboratory conditions. Pore water species such as SRP are transported with the water flow into the overlying water body, whereas SO42- and O2 are transported from the overlying water into the sediment. Due to the oxidation of Fe2+, phosphorus is fixed into the sediment, a result confirmed by P-fractionation. Microbiological investigations of the burrow walls demonstrated that the bioirrigation activity enhances the microbial abundance, changes the community structure, and increases the potential of enzymatic hydrolysis.
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Influência da velocidade cross-flow na câmara de flotação na eficiência de unidades de flotação por ar dissolvido tratando água para abastecimento / The influence of cross-flow velocity in the flotation chamber on efficiency of a dissolved air flotation unit treating drinking waterAraújo, Cláudio Júnior 07 October 2010 (has links)
O reator de FAD deve propiciar condições adequadas para contato entre as micro-bolhas e os flocos formados no pré-tratamento e também condições para que o conjunto floco/bolha possa ser direcionado ao topo do reator, e assim ser removido. O projeto de pesquisa visou estudar condições hidrodinâmicas proporcionadas pela variação da Velocidade Cross-Flow (VCF) e assim verificar a influência na eficiência de uma estação piloto de flotação por ar dissolvido. A VCF é importante parâmetro para concepção de unidades de FAD e é função da vazão de entrada no tanque de flotação e da área entre o nível d\'água no tanque de flotação e o anteparo que separa a zona de contato da zona de separação. A velocidade cross-flow constitui um parâmetro de grande importância para projetos de unidades de flotação. Nesta região de transição entre a zona de contato e a zona de separação, ocorre a passagem do conjunto floco/bolha, e turbulência excessiva pode causar o rompimento do conjunto e assim comprometer a eficiência da flotação. Além disso, o padrão de escoamento observado na zona de separação dos flotadores, onde ocorre a separação dos aglomerados \"flocos + bolhas\", depende fortemente do valor médio da velocidade cross-flow, conforme comentado por Lundh et al. (2000 e 2002) e por Reali e Patrizzi (2007). Daí a necessidade de se investigar mais profundamente a influência da VCF na eficiência da clarificação por flotação. O projeto de pesquisa foi dividido em duas etapas. Para realização das etapas foi estudado um tipo de água preparada em laboratório, através da adição de substância húmica e caulinita, para obtenção de cor aparente e turbidez, respectivamente. A água estudada possui cor aparente e turbidez moderada (1 mg/L de substância húmica e 8,5 mg/L de caulinita) resultando em valores de turbidez por volta de 7 NTU e cor aparente por volta de 40 UH. A etapa 1 consistiu na determinação do par, pH de coagulação e dosagem de coagulante (sulfato de alumínio), gradiente médio de floculação e tempo médio de floculação adequado para a água de estudo. Para realização da etapa 1 foi utilizado equipamento de flotação de bancada de regime de batelada (Flotateste), que se encontra nas dependências do Laboratório de Tratamento Avançado e Reuso de Águas - LATAR/SHS/EESC/USP. Foram mantidos fixos os seguintes parâmetros: \'T IND.MR\', \'G IND.MR\', \'T IND.F\', \'G IND.F\', \'P IND.SAT\', \'T IND.REC\', \'V IND.FLOT\'. Conforme preconizado por Reali et al (2007), foi variada a dosagem de coagulante. Após determinado o melhor par pH e dosagem de coagulante foram realizados ensaios visando determinar o melhor \'G IND.F\' e \'T IND.F\' para a água em estudo. Para a água de estudo foram escolhidas duas condições de potencial Zeta, determinados na etapa 1 do projeto de pesquisa. A primeira condição o potencial Zeta permaneceria com valor próximo de 0 mV e na segunda condição o potencial Zeta seria positivo, por volta de +12 mV. A etapa 2 consistiu em variar a velocidade cross-flow, através da variação da altura do vertedor de saída da água flotada de uma unidade piloto de flotação, de forma a se obter diferentes valores de VCF (mantendo-se constantes os valores de tempo de contato e taxa de aplicação superficial na zona de contato), para dois valores de Taxas de Aplicação Superficial (TAS) (7,67 m/h e 15 m/h) na zona de separação e os dois valores de potencial Zeta (PZ), e com isto avaliar a sua influencia na eficiência de remoção de sólidos suspensos totais, cor e turbidez da instalação piloto retangular de FAD. / The reactor DAF should provide adequate conditions for contact between the micro-bubbles and the flakes formed in the pretreatment conditions and also for the aggregate flocs/bubble can be directed to the top of the reactor, and thus be removed. The research project aimed at studying hydrodynamic conditions provided by the variation of Cross-Flow Velocity (VCF) and thus checks the influence on the efficiency of a pilot plant of dissolved air flotation. The VCF is an important parameter to design units of DAF and is a function of input flow in the flotation tank and the area between the water level in the flotation tank and the bulkhead that separates the contact zone of the zone of separation. The cross-flow velocity is a parameter of great importance to projects of flotation units. In this region of the transition zone between the contact zone and the separation zone, occurs the passage of the aggregate flocs/bubble, and excessive turbulence can cause disruption of the aggregate and thereby harm the flotation efficiency. Moreover, the pattern of flow observed in the flotation separation zone, which occurs the separation of aggregates \"flakes + bubbles\", depends strongly on the average value of cross-flow velocity as described by Lundh et al. (2000 and 2002) and Reali and Patrizzi (2007). Hence the needs to investigate further the influence of VCF on the clarification efficiency by flotation. The research project was divided into two steps. To perform the steps has been studied a type of water prepared in the laboratory, through the addition of humic substances and kaolin, to obtain apparent color and turbidity, respectively. The study water has moderate turbidity and apparent color (1 mg/L of humic substance and 8.5 mg/L of kaolin) resulting in turbidity values around 7 NTU and color apparent by 40 HU. Step 1 consisted in the determination of the pair, coagulation pH and coagulant dosage (aluminum sulfate), flocculation gradient and time flocculation suitable for the study water. For the implementation of step 1 was used bench batch flotation system equipment (Flotatest), located on the Laboratory for Advanced Treatment and Reuse Water - LATAR / SHS / EESC / USP. Were kept fixed the following parameters: \'T IND.MR\', \'G IND.MR\', \'T IND.F\', \'G IND.F\', \'P IND.SAT\', \'T IND.REC\', \'V IND.FLOT\'. As predicted by Reali et al (2007), was varied the dosage of coagulant. After determined the best pair of coagulant dosage and pH coagulation the tests were performed to determine the best \'G IND.F\' and \'T IND.F\' for the study water. For the study water were chosen two conditions of Zeta potential values, determined in the step 1 of the research project, where the first condition the Zeta potential value kept near 0 mV and the second condition kept a positive value of Zeta potential, around +12 mV. The step 2 consisted of varying the cross-flow velocity, by varying the height of the outlet weir of the clarified water of the flotation pilot plant to obtain different values of VCF (keeping constant the values of time contact and application rate on the contact zone) for two values of superficial application rates (7.67 m/h and 15 m/h) in the zone of separation and the two values of Zeta potential (PZ) and then was availed the influence on removal efficiency of total suspended solids, colour and turbidity of the rectangular pilot plant of DAF.
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Avaliação da hemodinâmica cerebral através da técnica de ultrassonografia Doppler e suas correlações com as variações da pressão intracraniana em um modelo animal de hipertensão intracraniana / Evaluation of cerebral hemodynamics using the Doppler ultrasonography technique and its correlations with variations of intracranial pressure in an animal model of intracranial hypertensionSoares, Matheus Schmidt 28 March 2018 (has links)
Introdução: O aumento da pressão intracraniana (PIC) é um problema comum na prática neurocirúrgica, e a monitoração invasiva deste parâmetro faz parte da rotina de unidades de terapia intensiva. O Doppler transcraniano vem sendo testado na avaliação da hemodinâmica cerebral como parâmetro de avaliação não invasiva da PIC, porém há controvérsias na literatura sobre seu real benefício e utilidade nesta situação. Este estudo objetivou correlacionar os dados de avaliação do fluxo sanguíneo cerebral através da técnica de Doppler com as variações da monitoração invasiva da PIC na fase aguda de hipertensão intracraniana em um modelo animal. Métodos: Trata-se de um estudo experimental realizado em suínos. O experimento constou de dois grupos de animais (A e B) com hipertensão intracraniana gerada por insuflação com soro fisiológico de um balão no parênquima cerebral, sendo o grupo A com 4 mL e o grupo B com 7 mL. Nos dois grupos houve uma intervenção clínica com infusão de solução salina a 3% e uma simulação de intervenção cirúrgica (desinsuflação do balão). Em todos os momentos de insuflação do balão e das intervenções foram registrados os valores dos monitores de PIC e do Doppler: velocidades sistólica (VS), diastólica (VD), média (VM) do fluxo sanguíneo cerebral e índice de pulsatilidade (IP). Foram realizadas comparações do comportamento dos parâmetros avaliados pela ultrassonografia Doppler craniana (VS, VD, VM e IP) em relação às variações da PIC intraparenquimatosa. Resultados: Foram estudados 20 suínos sendo 10 no grupo A e 10 no grupo B. Um animal do grupo B foi excluído do estudo, pois foi a óbito antes do término do experimento. Após a insuflação do balão, como era de se esperar, a PIC no grupo B foi superior à do grupo A em todos os momentos, até a desinsuflação do mesmo. Realizada a correlação de Spearman observou-se correlação significativa entre IP e PIC, principalmente logo após insuflação do balão, ou seja, na elevação abrupta da PIC. Não houve correlação entre a PIC e os parâmetros VS, VD e VM. Também não houve variação significativa da PIC após infusão endovenosa de solução salina hipertônica. Conclusão: Este resultado demonstra o potencial do IP como bom parâmetro de avaliação de pacientes com suspeita de elevação hiperaguda e recente da PIC. Não se conseguiu demonstrar os mesmos resultados de correlação entre a PIC e as demais variáveis VS, VD e VM. Diante destes achados, adicionados aos dados conflitantes da literatura disponível até o momento, não se recomenda, por enquanto, a utilização desses parâmetros isoladamente como substitutos da monitoração invasiva da PIC, evidenciando a necessidade de mais estudos clínicos e experimentais / Introduction: Increased intracranial pressure (ICP) is a common problem in neurosurgical practice. Invasive monitoring of ICP in these cases is part of the intensive care unit routine. Transcranial Doppler has been tested in the evaluation of cerebral hemodynamics as a non-invasive evaluation of ICP, but there are controversies in the literature about its real benefit and usefulness in this situation. Thus, this study aimed to correlate the data of cerebral blood flow assessment using the Doppler technique and the invasive monitoring of ICP in the acute phase of intracranial hypertension in an animal model. Methods: This is an experimental study in pigs. During the experiment, an intracerebral expansive mass with an inflatable balloon was simulated. The experiment consisted of two groups (A and B) of animals with intracranial hypertension generated by a ballon inflation inside the cerebral parenchima, group A with 4 mL and group B with 7 mL. In both groups there was a clinical intervention with infusion of 3% saline solution and a simulation of surgical intervention (balloon drain out). The values of ICP and Doppler parameters (systolic (FVs), diastolic (FVd), and mean (FVm) cerebral blood flow velocities) were collected at all moments of balloon inflation and interventions, as well as the pulsatility index (PI). Comparisons of the behavior of the parameters evaluated by Doppler ultrasound (FVs, FVd, FVm and PI) were performed in relation to intraparenchymal ICP. Results: Twenty pigs were studied, 10 in group A and 10 in group B. One pig died in group B and it was excluded. After balloon inflation, as expected, ICP in group B was higher than in group A at all times, until the ballon was empty again. Significant correlation between PI and ICP was obtained when Spearman correlation was performed, mainly shortly after balloon inflation, that is, in the abrupt elevation of ICP. There was no correlation between ICP and FVs, FVd or FVm. There was also no significant change in ICP after intravenous infusion of hypertonic saline solution. Conclusion: These results demonstrate the potential of PI as a good parameter for the evaluation of patients with suspected ICP elevation. It was not possible to demonstrate the same correlation results between the ICP and FVs, FVd or FVm. Due to these results and also to the literature conflicting data to date, the use of these parameters alone as substitutes for the invasive monitoring of ICP is not recommended until now, which shows the need for further clinical and experimental studies
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Modelagem matemática da cinética da decomposição aeróbia da matéria orgânica / Mathematical modeling of organic matter aerobic decomposition kineticsFleck, Leandro 31 January 2014 (has links)
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Leandro Fleck.pdf: 1897702 bytes, checksum: b3e258336499f4a0de7936279b0ee27c (MD5)
Previous issue date: 2014-01-31 / The development of human activities generates high amounts of industrial effluent, which has a high impact on watercourses, mainly due to organic load constituents. Among the methods used to control water pollution, the method of mathematical modeling stands out, a simulation tool that allows the generation of future scenarios. This study proposes to generate a mathematical model of water quality that simulates the process of aerobic self-depuration of organic matter from watercourses. For this purpose, it was used a water bath coupled to a jar test, providing temperature control from 20 to 28 °C, and flow velocity from 0.29 to 0.87 m s-1, similarly to natural conditions. The trials were conducted using a synthetic effluent with an initial COD concentration of 50 mg L-1, based on a Central Composite Design (DCC), composed of seven trials. All trials lasted 15 days, with effluent samples collected daily for the analysis of Chemical Oxygen Demand (COD) and Dissolved Oxygen (OD). A mathematical equation was developed for each day of self-depuration. The final mathematical model gathers 15 equations of self-depuration. The significance of the equations was measured using the analysis of variance to 10%. To validate the proposed model, a self-depuration trial was carried out under the conditions of 26 °C and 0.38 m s-1 with an initial COD concentration of 30 mg L-1. The analysis of variance was performed for the proposed mathematical model as well as the analysis of normality and homoscedasticity for waste, with a significance level of 5%.There are indications that the temperature significantly had an influence in the kinetics of aerobic decomposition of organic matter in the first and from the sixth to the fifteenth day self-depuration. The flow velocity significantly influenced in the eighth and from the twelfth to the fifteenth day of self-depuration, and the interaction between the factors in the eighth and fifteenth day of self-depuration, with p-values lower than the significance level adopted. With a confidence interval of 90%, the equations representing the first and from the seventh to the fifteenth day of self-depuration are statistically significant, with coefficients of determination (R2) greater than 84%. The proposed model adequately described the experimental data obtained in the validation trial, presented p-value of 2.49 E-17, lower than the level of significance adopted, of 5%. Thus, the model proposed can be considered statistically significant, describing the total variation of responses, with a ratio of 99.46%. The proposed mathematical model described the process of self-depuration in watercourses within the temperature and flow velocity intervals in which it was generated / O desenvolvimento das atividades humanas teve como consequência direta a geração de elevada quantidade de efluentes industriais, altamente impactantes aos cursos hídricos receptores, devido principalmente à carga orgânica constituinte. Dentre os métodos utilizados para o controle da poluição hídrica, destaca-se a modelagem matemática, a qual, sendo uma ferramenta de simulação, possibilita a geração de cenários futuros. O presente estudo propõe a geração de um modelo matemático de qualidade da água que possibilite simular o processo de autodepuração aeróbia da matéria orgânica de um corpo hídrico. Para a realização do estudo utilizou-se um banho-maria acoplado a um jar test, possibilitando o controle da temperatura na faixa de 20 a 28 °C e velocidade de fluxo na faixa de 0,29 a 0,87 m s-1, valores típicos encontrados em condições naturais. Os ensaios foram conduzidos utilizando-se efluente sintético a partir de uma concentração inicial de DQO de 50 mg L-1, com base em um Delineamento Composto Central (DCC), composto por 7 ensaios. Todos os ensaios tiveram duração de 15 dias, com coletas diárias de amostras de efluente para análise de Demanda Química de Oxigênio (DQO) e Oxigênio Dissolvido (OD). Gerou-se uma equação matemática para cada dia de autodepuração. O modelo matemático final reúne 15 equações de autodepuração. A significância das equações foi avaliada utilizando-se a Análise de Variância a 10%. Realizou-se a validação do modelo proposto, com base em um ensaio de autodepuração conduzido nas condições de 26 °C e 0,38 m s-1 a partir de uma concentração inicial de DQO de 30 mg L-1. Realizou-se a análise de variância para o modelo matemático proposto, assim como análise de normalidade e homoscedasticidade para os resíduos, com um nível de significância de 5%. Há indícios de que a temperatura influenciou significativamente na cinética de decomposição aeróbia da matéria orgânica no primeiro e do sexto ao décimo quinto dia autodepuração. A velocidade de fluxo influenciou significativamente no oitavo e do décimo segundo ao décimo quinto dia de autodepuração e a interação entre os fatores, no oitavo e no décimo quinto dia de autodepuração, apresentando p-valores menores que o nível de significância adotado. Com um intervalo de confiança de 90%, as equações representativas do primeiro e do sétimo ao décimo quinto dia de autodepuração, são estatisticamente significativas, apresentando coeficientes de determinação (R2) superiores a 84%. O modelo proposto descreveu satisfatoriamente os dados experimentais obtidos no ensaio de validação, apresentado p-valor de 2,49E-17, menor que o nível de significância adotado, de 5%. Assim, considera-se o modelo proposto como sendo estatisticamente significativo, descrevendo a variação total das respostas, com uma proporção de 99,46%. O modelo matemático proposto descreve satisfatoriamente o processo natural de autodepuração em cursos hídricos, dentro dos limites de temperatura e velocidade de fluxo em que foi gerado
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Measurements in Idiopathic Normal Pressure Hydrocephalus : Computerized neuropsychological test battery and intracranial pulse wavesBehrens, Anders January 2014 (has links)
Idiopathic Normal Pressure Hydrocephalus (INPH) is a condition affecting gait, cognition and continence. Radiological examination reveals enlarged ventricles of the brain. A shunt that drains CSF from the ventricles to the abdomen often improves the symptoms. Much research on INPH has been focused on identifying tests that predict the outcome after shunt surgery. As part of this quest, there are attempts to find measurement methods of intracranial parameters that are valid, reliable, tolerable and safe for patients. Today's technologies for intracranial pressure (ICP) measurement are invasive, often requiring a burr-hole in the skull. Recently, a method for non-invasive ICP measurements was suggested: the Pulsatile Index (PI) calculated from transcranial Doppler data assessed from the middle cerebral artery. In this thesis the relation between PI and ICP was explored in INPH patients during controlled ICP regulation by lumbar infusion. The confidence interval for predicted ICP, based on measured PI was too large for the method to be of clinical utility. In the quest for better predictive tests for shunt success in INPH, recent studies have shown promising results with criteria based on cardiac related ICP wave amplitudes. The brain ventricular system, and the fluid surrounding the spinal cord are in contact. In this thesis it was shown that ICP waves could be measured via lumbar subarachnoid space, with a slight underestimation. One of the cardinal symptoms of hydrocephalus is cognitive impairment. Neuropsychological studies have demonstrated cognitive tests that are impaired and improve after shunt surgery in INPH patients. However, there is currently no standardized test battery and different studies use different tests. In response, in this thesis a fully automated computerized neuropsychological test battery was developed. The validity, reliability, responsiveness to improvement after shunt surgery and feasibility for testing INPH patients was demonstrated. It was also demonstrated that INPH patients were impaired in all subtests, compared to healthy elderly.
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Oro srauto greičio tyrimas aerodinaminio vamzdžio skerspjūvyje / Air flow velocity testing in wind tunnel cross area sectionPlėta, Vidmantas 23 July 2012 (has links)
Baigiamajame magistro darbe aptariama oro srauto greičio netolygumo aerodinaminiame vamzdyje problema ir aktualumas. Išanalizuota būdinga mokslinė literatūra ir aprašyti būdingiausi oro srauto greičio darbinės dalies skerspjūvyje nustatymo metodai. Naudojant CAD aplinkos programą sumodeliuotas trimatis aerodinaminio vamzdžio modelis ir pritaikius analizės baigtiniais elementais metodą, atliktas oro srauto greičio pasiskirstymo aerodinaminio vamzdžio darbinėje dalyje ir jos viduriniame skespjūvyje tyrimas. Tyrimo rezultatai išanalizuoti ir pateiktos išvados ir siūlymai. / In this master's thesis deals discusses the inadequacy of air flow speed in wind tunnel and the relevance of the problem. Performed analysis of the scientific literature and describe the most typical technique of air flow mesurements in wind tunnel. Using a CAD program modeled three-dimensional wind tunnel model and performed air flow velocity testing in wind tunenel test section and their midle cros area section usig CFD program. The results is evaluated and stated the conclusions and suggestions.
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