Enhancing Pump as Turbine (PAT) performances: A numerical investigation into the impact of impeller leading edge rounding.

Pump As Turbine (PAT) utility represents a major advance in the field of hydraulic engineering. This work aims to improve the PAT performance characteristics. The sharp impeller leading edge (original impeller) was revealed by flow analysis as exhibiting negative effects on the PAT performances due to flow separation and flow misalignment. The performances of rounded and original impeller leading edge were studied by Computational Fluid Dynamic (CFD) method carried out on ANSYS CFX. Although impeller leading edge rounding has notably improved the performances in off design conditions, the difference of efficiency between the both impeller types was decreasing when increasing the discharge. The hydraulic head generated by the rounded impeller leading edge was also slightly higher at part load conditions, but when increasing the discharge, the difference between the both heads became negligible. It appeared from numerical simulations that the impeller leading edge rounding allows to decrease the hydraulic losses of the individual sub-domains except the outlet pipe. For the seek of a comprehensive analysis, the significant losses were computed for the two impeller geometries. It was observed that the shock losses and swirling losses of the rounded impeller leading edge were lower at part load conditions, but when increasing the discharge, the both losses were lower for the original impeller geometry. The rounded impeller leading edge exhibited as well lower wall frictional losses for the entire operating range of discharge.

Prediction method of centrifugal pump running in turbine mode based on losses analysis.

Interest of Pump as Turbine (PAT) is growing with diverse applications in engineering. Usually, the data of PATs are not available in the hands of pump manufacturers. Therefore, performance prediction methods appear as an important research area of PATs. The current prediction methods reposed on expensive, inaccurate and time consuming experimental methods. In the scope of this work, a generic and robust prediction method is built up for a centrifugal impeller PAT. The most significant hydraulic losses were derived in PAT mode, these are namely, the shock losses at the impeller inlet, the swirling losses at the impeller outlet and the impeller wall frictional losses. The Euler head, the available total head and the hydraulic efficiency were computed as well. The global efficiency was computed taking into account the machine mechanical and volumetric efficiencies, enabling therefore to perform comparison of the new prediction method with experimental, computational fluid dynamic (CFD), Rossi and Perez performances prediction methods. From where it resulted a good agreement between the given prediction methods for the entire range of operation, confirming the robustness and the applicability of the developed prediction method. The relative difference between the new prediction method and CFD data and between the new prediction method and experimental data remained higher for lower discharge conditions, notably for extreme part load conditions, where a small error could result in very high relative difference.

Multicentric Study to Assess Helicobacter pylori Incidence, Patient Reported Adverse Events, Compliance and Effectiveness, in Real-World Setting.

Helicobacter pylori ( H. pylori) plays an important role in chronic gastritis and globally it is estimated to be present in half of the world's population. In Portugal, prevalence reaches 85% and its eradication is recommended using quadruple antibiotic therapy, with or without bismuth. We intended to characterize the prescribed treatments evaluating effectiveness, adverse outcomes and compliance in a real-world setting in a primary care unit. A prospective multicenter observational cohort study was developed in five primary care units of Braga, Portugal. Patients diagnosed with H. pylori infection from August 2021 to January 2022 were included. Data were collected by interview (3 weeks after treatment) and review of medical records. Comparison between two groups of treatment and multivariable analysis was conducted. We estimated 13.4 cases per 1000 adults/year from 185 diagnoses. Therapy with bismuth was the most prescribed (83.8%) with a 96.7% eradication rate. There were no significant differences between treatments. Adverse events were reported in 73.8% of inquiries and female patients were associated with higher reports of nausea (p = 0.03) and metallic taste (p = 0.02). Both eradication schemes were effective and secure. The higher rate of adverse outcomes should be validated but it could influence the debate concerning treating all patients, especially in low gastric cancer-prevalence regions.

Estimation of suspended sediment concentration in Guamá River in the Amazon region.

Monitoring of the suspended sediment concentration (SSC) is important for the analysis of morphological processes in watersheds and rivers, river habitats, and human activities associated with river management. Acoustic Doppler current profilers (ADCP) are used for measurements of flow and velocity in rivers through acoustic waves, which can also be converted into sediment concentrations. In this context, the objective is to verify the applicability of the use of ADCPs (Sontek YSI, model M9 River Surveyor) as an alternative for SSC estimates, this being a recent application of the equipment, mainly in rivers in the Amazon region rich in sediments in suspension. Thus, the Gartner method was used, calibrating its equation with the concentrations obtained by the point sampling method, collected with a bottle of Van Dorn in the Guamá River, Amazon, Brazil. The method used to obtain the SSC with data measured via ADCP resulted in a satisfactory estimate of the concentrations. The correlations between the measured and estimated sediment concentrations had R2 = 0.6827 for point sampling method and R2 = 0.8103 for vertically averaged SSC. These satisfactory results demonstrate the potential of using ADCP to estimate sediments suspended in Amazon basin.

High CO2 effects on growth and biometal contents in the pioneer species Senna reticulata: climate change predictions.

The aim of the present study consisted in evaluating the effects of CO2 enrichment on the growth and biometal/nutrient content and accumulation in Senna reticulata germinated under two different carbon dioxide concentrations: atmospheric (360 mg L-1) and elevated (720 mg L-1). Biometal/nutrient determinations were performed on three different plant portions (leaflets, stem and root) using flame atomic absorption spectrometry. In general, the biometal and nutrient stoichiometries in roots were increased, probably due to reduced transpiration, and consequent biometal accumulation. An Artifical Neural Network analysis suggests that Mg, Na and Fe display the most different behavior when comparing plants germinated at atmospheric and elevated CO2 conditions. Biomass and growth increases and certain elemental levels indicate that S. reticulata benefits from increased CO2 levels, however some results indicate the contrary, making further studies in this context necessary, as these changes may lead to direct effects on food safety, crop yields, and phytoremediation efficiency.

Contribution to the marine propeller hydrodynamic design for small boats in the Amazon region / Contribuição ao projeto hidrodinâmico de propulsores marítimos voltados as pequenas embarcações da região Amazônica

In the Amazon, river navigation is very important due to the length of navigable rivers and the lack of alternative road networks. Boats usually operate in unfavorable conditions, since there is no hydrodynamic relation among propellers, geometry, and the dimensions of the boat hull. Currently, there is no methodology for propeller hydrodynamic optimization with low computational cost and easy implementation in the region. The aim of this work was to develop a mathematical approach for marine propeller design applied to boats typically found on Amazon rivers. We developed an optimized formulation for the chord and pitch angle distributions, taking into account the classical model of Glauert. A theoretical analysis for the thrust and torque relationships on an annular control volume was performed. The mathematical model used was based on the Blade Element Momentum Theory (BEMT). We concluded that the new methodology proposed in this work demonstrates a good physical behavior when compared with the theory of Glauert and the experimental data of the Wageningen B3-50 propeller.

Na Amazônia, a navegação é muito importante devido a extensão de rios navegáveis e a falta de redes rodoviárias alternativas. As embarcações geralmente trabalham em condições desfavoráveis, uma vez que não há relação entre a hidrodinâmica dos hélices, geometria e as dimensões do casco da embarcação. Atualmente, não há metodologia para otimização hidrodinâmica com baixo custo computacional e fácil implementação na região. O objetivo deste trabalho foi o desenvolvimento de uma abordagem matemática voltada para o projeto de propulsores marítimos aplicados as embarcações tipicamente encontradas nos rios da Amazônia. Nós desenvolvemos uma formulação otimizada para o cálculo das distribuições de corda e ângulo de torção, considerando o modelo clássico de Glauert. Uma análise teórica para as relações de empuxo e torque em um volume de controle anular foi realizado. O modelo matemático utilizado foi baseado na teoria do momento do elemento de pá (BEMT). Concluímos que a nova metodologia, proposta neste trabalho, demonstra bom comportamento físico quando comparado com a teoria de Glauert e os dados experimentais do propulsor Wageningen B3-50.

An Analysis of Total Phosphorus Dispersion in Lake Used As a Municipal Water Supply.

In Belém city is located the potable water supply system of its metropolitan area, which includes, in addition to this city, four more municipalities. In this water supply complex is the Água Preta lake, which serves as a reservoir for the water pumped from the Guamá river. Due to the great importance of this lake for this system, several works have been devoted to its study, from the monitoring of the quality of its waters to its hydrodynamic modeling. This paper presents the results obtained by computer simulation of the phosphorus dispersion within this reservoir by the numerical solution of two-dimensional equation of advection-diffusion-reaction by the method θ/SUPG. Comparing these results with data concentration of total phosphorus collected from November 2008 to October 2009 and from satellite photos show that the biggest polluters of the water of this lake are the domestic sewage dumps from the population living in its vicinity. The results obtained indicate the need for more information for more precise quantitative analysis. However, they show that the phosphorus brought by the Guamá river water is consumed in an area adjacent to the canal that carries this water into the lake. Phosphorus deposits in the lake bottom should be monitored to verify their behavior, thus preventing the quality of water maintained therein.

An Investigation of a Mathematical Model for the Internal Velocity Profile of Conical Diffusers Applied to DAWTs.

The Diffuser Augmented Wind Turbines (DAWTs) have been widely studied, since the diffusers improve the power coefficient of the wind turbine, particularly of small systems. The diffuser is a device which has the function of causing an increase on the flow velocity through the wind rotor plane due to pressure drop downstream, therefore resulting in an increase of the rotor power coefficient. This technology aids the turbine to exceed the Betz limit, which states that the maximum kinetic energy extracted from the flow is 59.26%. Thus, the present study proposes a mathematical model describing the behavior of the internal velocity for three conical diffusers, taking into account the characteristics of flow around them. The proposed model is based on the Biot-Savart's Law, in which the vortex filament induces a velocity field at an arbitrary point on the axis of symmetry of the diffusers. The results are compared with experimental data obtained for the three diffusers, and present good agreement.

Como combater hanseníase / How to prevent hanseniasis

Säo preconizadas várias medidas a curto, médio e longo prazos, para combater a hanseníase. Nas medidas a curto prazo, é enfocada a importância do esclarecimento do doente e comunicantes, sobre a hanseníase, e sobre a possibilidade da cooperaçäo dos doentes e conviventes na descoberta de novos casos, e a cooperaçäo que eles podem dar a profilaxia da doença. Nas medidas a médio prazo, säo indicadas a fundaçäo de um Instituto de pesquisas Científicas, e palestras em centros comunitários de doentes e comunicantes, focalizando-se os problemas e dúvidas sobre a doença e os doentes. Nas medidas a longo prazo, säo indicadas para ensino obrigatório nos curriculos do 1§ e 2§ graus, a higiene e as medidas necessárias a melhoriia da saúde em nosso país

Hanseniase: imagem, educacao, integracao e relacionamento medico-paciente / Image, education and integration and relationship doctor-patient

Embora ainda utilizados em campanhas de angariação de donativos, os aspectos graves da hanseníase são menos comuns, graças ao diagnostico e tratamento precoces. Esta nova imagem da hanseníase deve ser propagada pela educação sanitária, dirigida especialmente para doentes e comunicantes. A integração deve referir-se não só à hanseníase mas também aos leprólogos que se viram segregados da medicina devido ao pejorativo lepra. O bom relacionamento com o paciente depende de que seu médico seja também um psicólogo permanente, desde o diagnostico da doença