RESUMO
The main objective of this study was to evaluate the impact of the length and retention time of a tubular helical flow flocculator (THFF) on the elimination of turbidity and color from raw water, to obtain quality treated water for consumption in areas rural. For this, a large-scale field experimental system was used, the THFF was built with 4-inch diameter polyethylene hose and coupled to a sedimentation and filtration process. For the different experimental tests, aluminum sulfate was chosen as the coagulant. To find the optimal dose of coagulant, jar tests were previously carried out. For the tests the length of the THFF was varied (50 m and 75 m), flow rates of 0.25, 0.5, 0.75, 1 and 2 L/s and turbidity ranges of <10, 10-20, 21-50, 51-100 and > 100 NTU of raw water were tested. An evaluation of the hydraulic behavior of the THFF was carried out through an analysis of the temporal distribution curve of the concentration of a tracer, applying the Wolf-Resnick model. The average results revealed a haze and color removal efficiency of 98.07 % and 98.50 %, respectively. The residence time and velocity gradient exhibited variations in a range of 2.25-35.0 min and 3.64 to 56.94 s-1, respectively. It was evident that the operation and effectiveness of THFF are directly influenced by the turbidity of the raw water, the residence time and the velocity gradient. These findings indicate that THFF could play a valuable role as a flocculation unit in a purification system, mainly the existence of a plug-type flow was observed. The findings indicate that THFF, complemented by settling and filtration processes, could be a valuable tool for implementation in rural areas.
RESUMO
The maximum stresses on a femoral stem must be known for selecting the right size and shape of the shaft cross-sectional area for reducing the stress shielding effect generated after the total hip arthroplasty (THA) surgical procedure. The methodology proposed in this study provides the tools to the designers of femoral stems and orthopedic surgeons to select the adequate femoral stem cross section, decreasing the stiffness of the stem, thus reducing the stress shielding effect in the patient bones. The first contribution is the theoretical development of the maximum static stress calculation for 12 different femoral stem models with the beam theory, followed by the comparison with the static finite element analysis (FEA) simulations and finally the experimental corroboration of one femoral stem model measuring the strain with linear strain gages and transform it to stresses, the three different approaches provide comparable results, with a maximum average error of less than 8.5%. The second contribution is the formulation of a new selection methodology based on maximum stresses in the femoral stem and the cross section area for decreasing the stress shielding effect, optimizing the area needed for withstand the loads and decreasing the overall stiffens of the stem.
Assuntos
Artroplastia de Quadril , Prótese de Quadril , Artroplastia de Quadril/métodos , Fêmur/cirurgia , Análise de Elementos Finitos , Humanos , Desenho de Prótese , Estresse MecânicoRESUMO
If Schistosoma mansoni infection could be detected in its early stages, especially before the egg deposition in the host tissues, the development of severe pathologic lesions could be efficiently prevented. We therefore developed an indirect enzyme-linked immunosorbent assay based on the detection of specific IgG against schistosomula antigens (ELISA-SmTeg). The assay was applied in sera samples from non-infected and infected mice collected seven and 15 days post-infection. The results were compared to the number of adult worms obtained by perfusion of the murine hepatic system 50 days post-infection. The sensitivity and specificity of the ELISA-SmTeg were 100% (p = 0.0032 and 0.0048 respectively for seven and 15 days of infection) with a cutoff value of 0.15 (p = 0.0002). Our findings show a novel low-cost serological assay using antigens which are easy to obtain, which was able to detect all the infected mice as early as seven days post-infection.
A detecção da infecção pelo helminto Schistosoma mansoni quando realizada nas fases iniciais, especialmente antes da oviposição nos tecidos do hospedeiro, pode impedir de forma eficiente o desenvolvimento de graves lesões patológicas. Baseado nisto, foi desenvolvido um ensaio imunoenzimático indireto para detecção de anticorpos IgG específicos contra antígenos de esquistossômulos (ELISA-SmTeg). Este ensaio foi aplicado em amostras sorológicas de camundongos não infectados, da mesma forma que de camundongos recentemente infectados, após sete e 15 dias de infecção. Os resultados foram comparados com o número de vermes adultos obtidos por perfusão do sistema hepático murino 50 dias pós-infecção. A sensibilidade e a especificidade do novo método, denominado ELISA-SmTeg, foram de 100% (p = 0,0032, 0,0048, respectivamente, durante sete e 15 dias de infecção) com um valor de corte de 0,15 (p = 0,0002). Nossos resultados mostraram que um ensaio de baixo custo, que utiliza antígenos de fácil obtenção, é capaz de discriminar a esquistossomose mansoni em modelo experimental de forma precoce, incluindo sete dias pós-infecção.