58 resultados para Streamlines
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It is well known that the numerical solutions of incompressible viscous flows are of great importance in Fluid Dynamics. The graphics output capabilities of their computational codes have revolutionized the communication of ideas to the non-specialist public. In general those codes include, in their hydrodynamic features, the visualization of flow streamlines - essentially a form of contour plot showing the line patterns of the flow - and the magnitudes and orientations of their velocity vectors. However, the standard finite element formulation to compute streamlines suffers from the disadvantage of requiring the determination of boundary integrals, leading to cumbersome implementations at the construction of the finite element code. In this article, we introduce an efficient way - via an alternative variational formulation - to determine the streamlines for fluid flows, which does not need the computation of contour integrals. In order to illustrate the good performance of the alternative formulation proposed, we capture the streamlines of three viscous models: Stokes, Navier-Stokes and Viscoelastic flows.
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In this paper, space adaptivity is introduced to control the error in the numerical solution of hyperbolic systems of conservation laws. The reference numerical scheme is a new version of the discontinuous Galerkin method, which uses an implicit diffusive term in the direction of the streamlines, for stability purposes. The decision whether to refine or to unrefine the grid in a certain location is taken according to the magnitude of wavelet coefficients, which are indicators of local smoothness of the numerical solution. Numerical solutions of the nonlinear Euler equations illustrate the efficiency of the method. © Springer 2005.
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Dissertação de natureza científica para obtenção do grau de Mestre em Engenharia Informática e de Computadores
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Relatório Final de Estágio apresentado à Escola Superior de Dança, com vista à obtenção do grau de Mestre em Ensino da Dança.
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A implementação da evolução tecnológica no setor da construção tem se caracterizado pelo aparecimento de novas tecnologias que dinamizam os processos de troca de informação entre os vários intervenientes no ciclo de vida do empreendimento. O surgimento da tecnologia Building Information Modeling - BIM assente na modelação paramétrica e na interoperabilidade suportada em ficheiros de padrão aberto (IFC) pressupõem um novo paradigma na forma como são tratados os processos de troca de informação entre os vários intervenientes no ciclo de vida dos empreendimentos. Com base no BIM o Construction Operations Building Information Exchange – COBie, é outra tecnologia recente que recolhe informações não geométricas associadas ao modelo e em conjunto com a informação geométrica produzida pelo BIM fazem parte dos documentos de entrega para a fase Facility Management – FM. O objetivo da presente dissertação centrou-se no estudo da evolução de um modelo BIM de construção para a gestão de empreendimento. Foi desenvolvido o estudo de um modelo protótipo que incidiu na utilização de softwares para verificação e aplicação das tecnologias COBie e BIM e também foi sincronizado com a fase FM. Da aplicação dos requisitos COBie e modelação BIM foram extraídas informações geométricas e não geométricas preenchidas nas folhas de trabalho COBie. As principais conclusões do estudo realizado foram que as tecnologias COBie e BIM têm pouca implantação a nível nacional e a sua integração dinamiza os processos, reduzindo custos e aumentando a qualidade da informação fornecida.
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Dissertação para obtenção do Grau de Mestre em Engenharia Informática
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Dissertação de mestrado integrado em Engenharia Industrial
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The 22q11.2 deletion syndrome (22q11DS) is a widely recognized genetic model allowing the study of neuroanatomical biomarkers that underlie the risk for developing schizophrenia. Recent advances in magnetic resonance image analyses enable the examination of structural connectivity integrity, scarcely used in the 22q11DS field. This framework potentially provides evidence for the disconnectivity hypothesis of schizophrenia in this high-risk population. In the present study, we quantify the whole brain white matter connections in 22q11DS using deterministic tractography. Diffusion Tensor Imaging was acquired in 30 affected patients and 30 age- and gender-matched healthy participants. The Human Connectome technique was applied to register white matter streamlines with cortical anatomy. The number of fibers (streamlines) was used as a measure of connectivity for comparison between groups at the global, lobar and regional level. All statistics were corrected for age and gender. Results showed a 10% reduction of the total number of fibers in patients compared to controls. After correcting for this global reduction, preserved connectivity was found within the right frontal and right parietal lobes. The relative increase in the number of fibers was located mainly in the right hemisphere. Conversely, an excessive reduction of connectivity was observed within and between limbic structures. Finally, a disproportionate reduction was shown at the level of fibers connecting the left fronto-temporal regions. We could therefore speculate that the observed disruption to fronto-temporal connectivity in individuals at risk of schizophrenia implies that fronto-temporal disconnectivity, frequently implicated in the pathogenesis of schizophrenia, could precede the onset of symptoms and, as such, constitutes a biomarker of the vulnerability to develop psychosis. On the contrary, connectivity alterations in the limbic lobe play a role in a wide range of psychiatric disorders and therefore seem to be less specific in defining schizophrenia.
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Background Demand for home care services has increased considerably, along with the growing complexity of cases and variability among resources and providers. Designing services that guarantee co-ordination and integration for providers and levels of care is of paramount importance. The aim of this study is to determine the effectiveness of a new case-management based, home care delivery model which has been implemented in Andalusia (Spain). Methods Quasi-experimental, controlled, non-randomised, multi-centre study on the population receiving home care services comparing the outcomes of the new model, which included nurse-led case management, versus the conventional one. Primary endpoints: functional status, satisfaction and use of healthcare resources. Secondary endpoints: recruitment and caregiver burden, mortality, institutionalisation, quality of life and family function. Analyses were performed at base-line, and at two, six and twelve months. A bivariate analysis was conducted with the Student's t-test, Mann-Whitney's U, and the chi squared test. Kaplan-Meier and log-rank tests were performed to compare survival and institutionalisation. A multivariate analysis was performed to pinpoint factors that impact on improvement of functional ability. Results Base-line differences in functional capacity – significantly lower in the intervention group (RR: 1.52 95%CI: 1.05–2.21; p = 0.0016) – disappeared at six months (RR: 1.31 95%CI: 0.87–1.98; p = 0.178). At six months, caregiver burden showed a slight reduction in the intervention group, whereas it increased notably in the control group (base-line Zarit Test: 57.06 95%CI: 54.77–59.34 vs. 60.50 95%CI: 53.63–67.37; p = 0.264), (Zarit Test at six months: 53.79 95%CI: 49.67–57.92 vs. 66.26 95%CI: 60.66–71.86 p = 0.002). Patients in the intervention group received more physiotherapy (7.92 CI95%: 5.22–10.62 vs. 3.24 95%CI: 1.37–5.310; p = 0.0001) and, on average, required fewer home care visits (9.40 95%CI: 7.89–10.92 vs.11.30 95%CI: 9.10–14.54). No differences were found in terms of frequency of visits to A&E or hospital re-admissions. Furthermore, patients in the control group perceived higher levels of satisfaction (16.88; 95%CI: 16.32–17.43; range: 0–21, vs. 14.65 95%CI: 13.61–15.68; p = 0,001). Conclusion A home care service model that includes nurse-led case management streamlines access to healthcare services and resources, while impacting positively on patients' functional ability and caregiver burden, with increased levels of satisfaction.
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Culverts are common means to convey flow through the roadway system for small streams. In general, larger flows and road embankment heights entail the use of multibarrel culverts (a.k.a. multi-box) culverts. Box culverts are generally designed to handle events with a 50-year return period, and therefore convey considerably lower flows much of the time. While there are no issues with conveying high flows, many multi-box culverts in Iowa pose a significant problem related to sedimentation. The highly erosive Iowa soils can easily lead to the situation that some of the barrels can silt-in early after their construction, becoming partially filled with sediment in few years. Silting can reduce considerably the capacity of the culvert to handle larger flow events. Phase I of this Iowa Highway Research Board project (TR-545) led to an innovative solution for preventing sedimentation. The solution was comprehensively investigated through laboratory experiments and numerical modeling aimed at screening design alternatives and testing their hydraulic and sediment conveyance performance. Following this study phase, the Technical Advisory Committee suggested to implement the recommended sediment mitigation design to a field site. The site selected for implementation was a 3-box culvert crossing Willow Creek on IA Hwy 1W in Iowa City. The culvert was constructed in 1981 and the first cleanup was needed in 2000. Phase II of the TR 545 entailed the monitoring of the site with and without the selfcleaning sedimentation structure in place (similarly with the study conducted in laboratory). The first monitoring stage (Sept 2010 to December 2012) was aimed at providing a baseline for the operation of the as-designed culvert. In order to support Phase II research, a cleanup of the IA Hwy 1W culvert was conducted in September 2011. Subsequently, a monitoring program was initiated to document the sedimentation produced by individual and multiple storms propagating through the culvert. The first two years of monitoring showed inception of the sedimentation in the first spring following the cleanup. Sedimentation continued to increase throughout the monitoring program following the depositional patterns observed in the laboratory tests and those documented in the pre-cleaning surveys. The second part of Phase II of the study was aimed at monitoring the constructed self-cleaning structure. Since its construction in December 2012, the culvert site was continuously monitored through systematic observations. The evidence garnered in this phase of the study demonstrates the good performance of the self-cleaning structure in mitigating the sediment deposition at culverts. Besides their beneficial role in sediment mitigation, the designed self-cleaning structures maintain a clean and clear area upstream the culvert, keep a healthy flow through the central barrel offering hydraulic and aquatic habitat similar with that in the undisturbed stream reaches upstream and downstream the culvert. It can be concluded that the proposed self-cleaning structural solution “streamlines” the area upstream the culvert in a way that secures the safety of the culvert structure at high flows while producing much less disturbance in the stream behavior compared with the current constructive approaches.
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During the 2010 legislative session, Senate File 2375, or Streamlined Sales and Use Tax Administration Act, was approved by the general assembly. The act modified the Iowa sales use tax law to keep the state in compliance with the National Streamlines Sales and Use Tax Agreement. This issue review provides a brief update on the status of the agreement and its impact on Iowa.
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The velocity of a liquid slug falling in a capillary tube is lower than predicted for Poiseuille flow due to presence of menisci, whose shapes are determined by the complex interplay of capillary, viscous, and gravitational forces. Due to the presence of menisci, a capillary pressure proportional to surface curvature acts on the slug and streamlines are bent close to the interface, resulting in enhanced viscous dissipation at the wedges. To determine the origin of drag-force increase relative to Poiseuille flow, we compute the force resultant acting on the slug by integrating Navier-Stokes equations over the liquid volume. Invoking relationships from differential geometry we demonstrate that the additional drag is due to viscous forces only and that no capillary drag of hydrodynamic origin exists (i.e., due to hydrodynamic deformation of the interface). Requiring that the force resultant is zero, we derive scaling laws for the steady velocity in the limit of small capillary numbers by estimating the leading order viscous dissipation in the different regions of the slug (i.e., the unperturbed Poiseuille-like bulk, the static menisci close to the tube axis and the dynamic regions close to the contact lines). Considering both partial and complete wetting, we find that the relationship between dimensionless velocity and weight is, in general, nonlinear. Whereas the relationship obtained for complete-wetting conditions is found in agreement with the experimental data of Bico and Quere [J. Bico and D. Quere, J. Colloid Interface Sci. 243, 262 (2001)], the scaling law under partial-wetting conditions is validated by numerical simulations performed with the Volume of Fluid method. The simulated steady velocities agree with the behavior predicted by the theoretical scaling laws in presence and in absence of static contact angle hysteresis. The numerical simulations suggest that wedge-flow dissipation alone cannot account for the entire additional drag and that the non-Poiseuille dissipation in the static menisci (not considered in previous studies) has to be considered for large contact angles.
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Diplomityössä toteutettiin varastonhallintajärjestelmän hankinta prosessoimalla tietoa hallitusti varastonhallinnan kehittämiseksi. Kvalitatiivinen tapaustutkimus tehtiin tietojohtamisen näkökulmasta käyttäjälähtöisen C-CEI –menetelmän avulla haastattelemalla ja havainnoimalla tapausyritystä. Haastatteluja tehtiin 10 kertaa. Tutkimuksessa kartoitettiin ja kilpailutettiin kotimaiset järjestelmätoimittajat, joita löydettiin 15. Näistä toimittajista 6 vastasi vaatimuksia ja teki tarjouksen. Tutkimuksen lopuksi tehtiin järjestelmän hankintaehdotus. Tutkimuksen teoreettinen viitekehys koostui tietojohtamisesta, varastonhallinnasta ja ohjelmistotuotannosta. Tutkimuksessa pääkysymyksenä esitettiin miten tietojohtamisen avulla voidaan tukea varastonhallintajärjestelmän hankintaa. Tutkimuksessa havaittiin, että tietojärjestelmän hankinta varastonhallinnan osalta on moniulotteinen liiketoiminnan kehittämistehtävä. Tietojärjestelmähankinta tulisi siten nähdä liiketoimintaa eteenpäin vievänä mahdollisuutena. Lisäksi loppukäyttäjän vaatimusten kartoittamiseen tulisi sitoutua huolella ja suhtautua kriittisesti eri järjestelmävaihtoehtoihin. Vaatimusmäärittelyn asettaminen ja vaatimusten priorisoiminen ovat haasteellisia tehtäviä. Tiedon hallinnan aikana saatiin selville, että loppukäyttäjän vaatimusten mukainen tarjouspyyntö edesauttaa ensinnäkin tarjousten tekemistä mutta myös niiden prosessointia ja analysointia. Vain oikealla tiedolla ja sen yhteyksillä on merkitystä. Tutkimuksen perusteella tietojärjestelmän hankinta suositellaan tehtäväksi hallitsemalla tietoa systemaattisesti erityisesti sen alkuvaiheen aikana. Tietojohtaminen virtaviivaistaa hankkeen etenemistä ja aikataulutusta, vähentää loppukäyttäjän kustannuksia tehokkaalla kilpailutusmenettelyllä, edistää kilpailukykyä ja luo hyvän lähtökohdan koko tietojärjestelmän hankinnan läpiviemiselle ja yhteistyö-suhteen rakentumiselle kauppakumppaneiden välille.
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For inviscid fluid flow in any n-dimensional Riemannian manifold, new conserved vorticity integrals generalizing helicity, enstrophy, and entropy circulation are derived for lower-dimensional surfaces that move along fluid streamlines. Conditions are determined for which the integrals yield constants of motion for the fluid. In the case when an inviscid fluid is isentropic, these new constants of motion generalize Kelvin’s circulation theorem from closed loops to closed surfaces of any dimension.