Maximum level and time to peak of dam-break waves on mobile horizontal bed

Journal of Hydraulic Engineering, Vol. 135, No. 11, November 1, 2009This experimental study focuses the influence of bed material mobility and initial downstream water level on maximum water level and time to peak of dam-break waves. It covers horizontal bed conditions on fixed bed, sand bed, and pumice bed. Results include water surface level time evolution, maxima wave levels and time to peak. The influence of bed material mobility and downstream water level was identified and characterized, stressing the importance of using mathematical models with appropriate sediment transport formulations instead of purely hydrodynamic models to simulate dam-break waves on mobile bed channels

Determination of velocity fields of two-phase flows using PIV-PTV

No domínio da hidráulica fluvial, é fundamental conhecer o campo de velocidades das fases sólida (sedimentos) e líquida (água). A partir do campo de velocidades instantâneas é possível quantificar diversas variáveis incluindo intensidades da turbulência e tensões de corte e identificar zonas de separação, recirculação, etc. O desenvolvimento de técnicas óticas permitiu o desenvolvimento de instrumentos de medição baseados na aquisição e no processamento de imagens, nomeadamente o PIV (particle image velocimetry) e o PTV (particle tracking velocimetry). Neste artigo, apresenta-se um algoritmo que combina ambas as técnicas, PIV e PTV, permitindo assim, juntar os pontos fortes de cada uma das técnicas e possibilitando a medição simultânea do campo de velocidades da água e dos sedimentos e estudar mais detalhadamente a interação fluido-sedimentos. As vantagens e limitações do algoritmo proposto são exploradas e discutidas com recurso a um conjunto de experiências laboratoriais.In the domain of fluvial hydraulics, it is critical to know the velocity field of both solid (sediments) and liquid phases (water). From the velocity field it is possible to determine different variables such as shear stresses, identify recirculation regions, etc. The development of optical techniques allowed for measurement techniques based on image acquisition and processing, namely PIV (particle image velocimetry) and PTV (particle tracking velocimetry). In this paper an algorithm combining both PIV and PTV techniques is presented, allowing in this way to profit from each technique strong points and allowing the simultaneous measurement of the water and sediment layer velocity fields and to obtain a better know how of the fluid-sediment interaction. The advantages and limitations of the proposed techniques are explored and discussed by means of a laboratory experiment.Este trabalho teve o apoio financeiro do Projeto PTDC/ ECM-HID/6387/2014 – POCI-01-0145- FEDER-016825 – financiado por fundos do FEDER através do COMPETE2020 – Programa Operacional Competitividade e Internacionalização (POCI) e por fundos nacionais através da FCT – Fundação para a Ciência e a Tecnologia, I.

Organised turbulence over mobile and immobile hydraulically rough boundaries

33rd IAHR Congress: Water Engineering for a Sustainable EnvironmentThe present work is aimed at the study of near-bed organised turbulence over mobile and immobile, porous, hydraulically rough boundaries. The bed was permeable and composed of non-cohesive sediments. Two data sets were analysed, characterised by the same u*. The mobile bed data featured generalised sediment transport for all size fractions smaller than the d90. The fixed bed was obtained as result of an armouring process. Comparison of these data sets reveals differences on such parameters of the bursting cycle as the maximum shear stress and the transported momentum. These results point to a reorganization of turbulence, in the near-bed region, when the bed is mobile. The impacts of these reorganization are discussed, namely in what concerns the third order moments of the distributions of the velocity fluctuations

Experimental investigation of the flow field in the vicinity of an oscillating wave surge converter

PTDC/CTAOHR/30561/2017 PD/BD/705970/2014The main objective of this paper is to characterize the flow field on the front face of an oscillating wave surge converter (OWSC) under a regular wave. For this purpose, the longitudinal and vertical velocity components were measured using an Ultrasonic Velocity Profiler (UVP). In order to explain the main trends of the OWSC’s dynamics, the experimental data were firstly compared with the analytical results of potential theory. A large discrepancy was observed between experimental and analytical results, caused by the nonlinear behavior of wave-OWSC interaction that determine the turbulent field and the boundary layer. The experimental velocity field shows a strong ascendant flow generated by the mass transfer over the flap (overtopping) and flow rotation generated by the beginning of the flap deceleration and acceleration. These features (overtopping and flow rotation) have an important role on the power capture of OWSC and, therefore, analytical results are not accurate to describe the complex hydrodynamics of OWSC.publishersversionpublishe

Application of Scrum and PM Canvas in a Project-based Learning Approach

Project-based Learning (PBL) is a teaching and learning strategy that allows students to develop competences while working on projects. It is important to apply good management approaches in order to achieve all project and learning objectives. This paper presents an application of Scrum and Project Model Canvas (PM Canvas) to manage learning projects developed by teams of students in interaction with industrial companies. These projects are part of a Project-based Learning (PBL) approach developed in the fourth year of an integrated master program in Industrial Engineering and Management. A group of 5 students from the fifth year of the same degree gave support to the PBL teams regarding the utilization of these tools. The work was developed during one month with meetings every Fridays. These project management tools were applied to help the PBL teams to organize and share the tasks, as well as visualize and control the whole project. To evaluate the teams' performance and the way they are realizing the tasks, it was counted the number of tasks done in each weekday and the students were inquired in order to understand their perceptions of the use of these project management tools. The results revealed that the groups performed most of the tasks on Wednesday and the inquiry revealed that most of the PBL teams did not know and had never used project management tools. The inquiry also revealed that the project management tools were considered helpful for the control and organization of the project tasks, improving overall team performance.(undefined

Faecal indicator bacteria and listeria monocytogenes in ponds, natural and constructed wetlands: Evaluating water quality

info:eu-repo/semantics/publishedVersio

Aerobic biological treatment of wastewaters containing dichloromethane

BACKGROUND: Volatilization has been advanced as one of the predominant phenomena contributing to volatile organic carbon emissions from wastewater treatment plants (WWTPs). In this study, strategies for minimizing such air stripping losses when treating a liquid stream containing dichloromethane (DCM), aiming at decreasing the overall emission inventory from WWTPs, were investigated. RESULTS: System R1, consisting of a continuous flow stirred tank reactor (CSTR) treating a liquid stream containing DCM at a concentration of 12 mmol dm−3 presented a biodegradation efficiency (BE) of 68%, based upon chloride release, with 10% of measurable losses, mainly due to volatilization, and 22% of unmeasurable losses. System R2 introduced operational designs aiming at decreasing DCM volatilization. In Experiment R2.1, a biotrickling filter, through which the air stripped from the CSTR was driven, was introduced leading to a reduction from 10% to 7% on the measurable losses. In Experiment R2.2, the air stripped from the CSTR was recirculated at a flow rate of 2.4 dm3 h−1 through the reactormedium before entering the biotrickling filter. The BE was improved from 69% to 82% and the losses associated with air stripping were successfully reduced to 2%. The proposed design, including air recirculation and the biotrickling filter, increased the ratio between the biodegradation rate and the volatilization rate from 7 to 41. CONCLUSIONS: Recirculation of the gaseous effluent through the reactor medium, which allowed for higher residence time within the bioreactor, was shown to be a successful strategy for improving the treatment process, thus minimizing DCM volatilization losses

Eating behaviours in youths: a comparison between female and male athletes and non-athletes

Article first published online: 25 JUL 2013Objective: This study compared the different factors associated with eating behaviours among young female and male athletes and non-athletes. Method: A total of 580 female and male athletes and 362 female and male non-athletes between 10 and 19 years old participated. We used the subscales of the Eating Attitudes Test (EAT-26) to evaluate the factors associated with unhealthy eating behaviours. Results: We found higher scores for females on the Diet subscale compared with males, regardless of athletic group (p < .05). Non-athlete youths scored higher on this subscale compared with male athletes (p < .05). Our findings indicate higher scores for female athletes with regard to the Bulimia and Preoccupation with Food subscale compared with other the groups (p < .05). Moreover, we observed that non-athlete males were more likely to engage in binge eating compared with athletes of the same sex (p < .05). Finally, females had higher scores on the Oral Self subscale than males, regardless of athletic group (p < .05). Conclusion: We concluded that the factors associated with eating behaviours differ with regard to sex and group

New Nile blue derivatives as NIR fluorescent probes and antifungal agents

The synthesis of four new Nile Blue derivatives with hydrogen, propyl and/or aminopropyl groups as substituents of the amines of 5- and 9-positions is described. Photophysical properties were evaluated in acidified ethanol and aqueous solution at physiological pH. Antifungal activity is also studied through the obtention of MIC values.Thanks are due to Fundação para a Ciência e Tecnologia (FCT) and FEDER (European Fund for Regional Development)-COMPETE-QRENEU for financial support through the Chemistry Research Centre of the University of Minho (Ref. UID/QUI/00686/2013 and UID/QUI/0686/2016), CBMA (PEst OE/BIA/UI4050/2014) and a PhD grant to J.C.F. (SFRH/BD/133207/2017). The NMR spectrometer Bruker Avance III 400 is part of the National NMR Network (PTNMR) and are partially supported by Infrastructure Project No 022161 (co-financed by FEDER through COMPETE 2020, POCI and PORL and FCT through PIDDAC)