Methodology for Abrasive Wear Evaluation in Elevator Stage Centrifugal Pump Impellers

The abrasion resistance of the impellers depends on the characteristics of the materials used in their manufacture. In this work, a methodology is proposed for the evaluation of the abrasive wear of the plates of the centrifugal pump impellers, used in the gross water infrastructure station (GWIS) of sedimentary rivers, due to the sediment load variation and the river fluviometric dimension. In order to determine the wear mode and the relationship of the material-specific wear coefficient (K), due to the sediment concentration, a rotating ball abrasometer test was performed on SAE 8620, gray cast iron (GCI), and nodular cast iron (NCI), used in the manufacture of impellers. As an abrasive suspension, the concentrations of 1, 2, 3, 5, and 10 g L−1 of sediment were used in distilled water. The wear volume as a function of the relative velocity of the mixture in relation to the impeller blades was estimated mathematically. The results show that: i) The abrasive capacity of the sediments in different concentrations; ii) SAE 8620 steel was more resistant to abrasive wear; and iii) the rotational control of the pump as a function of sediment concentration and river level showed the possibility of reducing wear by 30%

Abrasive effects of sediments on impellers of pumps used for catching raw water

ABSTRACT This study presents an analysis of the abrasive effects of sediments from the bed of the Acre River, Brazil, on the wear of three different ferrous materials employed in the manufacture of impellers of centrifuge pumps used to catch raw water. In order to evaluate the abrasive wear and specific wear coefficient (k) as a function of sediment concentration, tests were conducted in samples of SAE 8620 steel, nodular cast iron and gray cast iron by using a rotary-ball abrasion meter. These tests employed abrasive slurry with concentration of 1, 2, 3, 5 and 10 g L-1 of sediments in distilled water. The volume of worn material as a function of the relative velocity of water flow in relation to the impeller blades was mathematically estimated. The experimental results showed that: i) The semi-angular and semi-rounded shapes of the sediments from the Acre River produced evidence of micro-grooving and plastic deformation in the three metallic alloys; ii) SAE 8620 steel showed higher resistance to abrasive wear than samples of gray and nodular cast iron; iii) the increase in the volume of worn material due to increment in sediment concentration and the relative velocity of the mixture (water + sediment) to the rotor pads

Mudanças sociais e gestão ecológica em questão: a experiência de mamirauá

Estudo sobre as mudanças sociais que envolveram as populações tradicionais desde a criação de uma unidade de conservação ambiental, no ano de 1990, na região do Médio Solimões, Amazônia brasileira, com o interesse de conservar uma área reconhecida como o maior ecossistema de várzea do mundo. A análise situa os produtores locais em relação ao mercado ecológico e aos agentes do desenvolvimento sustentável. O estudo se refere a 49 localidades da floresta alagada amazônica, com informações relativas aos anos de 1991 a 2006. A análise identifica os agentes sociais que integram o campo socioambiental que se constrói com as políticas de intervenção socioambiental.<br>Estudio sobre los cambios sociales que involucran a las poblaciones tradicionales mediante la creación de un ambiente protegido, en 1990, en el rio Solimões, Amazonia brasileña, en interés de la conservación de una zona reconocida como el ecosistema de humedal más grande del mundo . El análisis es los productores locales para el mercado y los agentes de desarrollo sostenible ecológico. El estudio se refiere a 49 ciudades en la selva amazónica inundada, que abarca los años 1991 a 2006. El análisis identifica los agentes sociales que integran el ámbito del medio ambiente, que se construye con políticas de intervención socioambiental.<br>Study on the social changes involving traditional population after the creation, in 1990, of an environmental conservation unit in the Mid-Solimões River, Brazilian Amazon aimed to conserve an area known as the largest wetland ecosystem in the world. The analysis places local producers in relation to the ecological market and agents of sustainable development. The study covers 49 localities of the Amazon flooded forest, with information obtained between 1991 and 2006. The analysis identifies the social agents who integrate the socio environmental field constructed with social environmental intervention policies

Additional file 1: of Stability of the HTLV-1 glycoprotein 46 (gp46) gene in an endemic region of the Brazilian Amazon and the presence of a significant mutation (N93D) in symptomatic patients

The research ethics committee. Source: Study protocol, 2015, Table S1. Description of values of AICM applied in the statistics (Bayesian inference) in the study data. Source: Study protocol, 2016. (PDF 1549 kb