in order to know the environmental behaviour of toxic pollutants it is fundamental to understandthe role of chemical components of a material on sorption of such pollutants.in this study, the sorption of amix of polycyclic aromatic hydrocarbons (pahs) by cork fractions (i.e. raw cork (cf), free extractive cork(fef) and nonsaponifiable (desf)) has been investigated to better understand the role ...

Kinetics of the chemical leaching of chalcocite from a low-grade copper ore in a ferric sulfate medium was investigated using the constrained least square optimization technique. The experiments were carried out for different particle sizes in both the reactor and column at constant Eh, pH, and temperature. The leaching rate increased with increase in the temperature. About 50% of the Cu recove...

Distribution of magnetic fields in the quiet-Sun internetwork areas has been affected by weak polarization (in particular Stokes Q and U) signals. To improve the signal-to-noise ratio (SNR) of the weak polarization signals, several approaches, including temporal integrations, have been proposed in the literature. In this study, we aim to investigate a proper temporal-integration time with which...

Equal channel angular pressing (ECAP) is carried out using two different configurations for the exit channel of the ECAP die, i.e., relieved and choked, with angles of 0.2 °. It is found that using a die with relieved exit channel, the sample was extruded for 6 passes with no surface cracks and an average cell size of 727 nm and a fraction of high angle grain boundaries of 54 % were achieved. M...

an ultrafine grained dual phase (ufg dp) steel containing niobium was produced by a new routeutilizing simple cold-rolling and subsequent intercritical annealing of ferrite/martensite duplex startingstructures. the effects of intercritical holding time on the microstructural evolutions and mechanicalproperties were studied. the results showed that increasing intercritical holding time enhnaced ...

the hot compression tests were carried on x45crniw189 valve steel (x45) in the temperature rangeof 1000– 1200 °c and the strain rate range of 0.004 – 0.5 s-1 in order to study the high temperaturesoftening behavior of this steel. for the exact prediction of flow stress, the effective stress-effectivestrain curves were obtained from experiments under various conditions. on the basis of experimen...

18 Bacterially-mediated fluxes of energy and matter are dynamic in time and space coupled with 19 shifts in bacterial community structure. Yet, our understanding of mechanisms shaping 20 bacterial biogeography remains limited. Near-surface seawater was collected during transits 21 between Honolulu and Station ALOHA in the North Pacific Subtropical Gyre to examine the 22 shape of occupancy-frequ...

abstract objective cardiac dysfunction is a major cause of death in patients with beta thalassemia. in these patients, repeated blood transfusion, ineffective erythropoiesis and increased gastrointestinal iron absorption lead to iron overload in the body and this induced heart failure. left ventricular ejection fraction was measured in major beta thalassemia (β-th) patients to detect the relati...

in this work, artificial neural network (ann) was utilized to develop a new model for the predictionof the kinematic viscosity of petroleum fractions. this model was generated as a function oftemperature (t), normal boiling point temperature (tb), and specific gravity (s). in order to developthe new model, different architectures of feed-forward type were examined. finally, the optimumstructure...

In this paper, convection heat transfer of Al2O3-water nanofluid turbulent flow through internally ribbed tubes with different rib shapes (rectangular, trapezoidal and semi-circular) is numerically investigated. For each rib shape, the optimum geometric ratio and volume fraction were calculated using entropy generation minimization technique. The governing equations in...