Metals are largely derived from the mantle or crust by partial melting and fluid-related leaching. Ligands can be provided from the same sources, or from the atmosphere, hydrosphere and biosphere. Transport is mainly by mechanical or mass transfer mechanisms and by fluids. On and near the surface, biological processes can also concentrate and transport ore components or remove non-ore component...

S U M M A R Y Gravity gradients are an effective method for delineating the extent of subsurface density anomalies. The change in subsurface density contrasts due to the seismic deformation gives rise to detectable gravity changes via the dilatational gravity signal or Bouguer anomaly. Solutions for the corresponding gravity gradients of these signals are developed for a vertical strikeslip fau...

In Tore Supra plasmas with fast wave electron heating, a critical threshold in the electron temperature gradient (inverted DeltaT(e)) is clearly observed, i.e., a finite value of inverted DeltaT(e) for which the turbulent heat diffusivity vanishes. The radial profile of this critical gradient is experimentally determined from a set of discharges characterized by similar plasma parameters with f...

18 Denitrification was measured in three structurally different coastal microbial mats by 19 using the stable isotope technique. The composition of the denitrifying community was 20 determined by analyzing the nitrite reductase (nirS and nirK) genes using clone libraries 21 and the GeoChip. The highest potential rate of denitrification (7.0±1.0 mmol N m d) 22 was observed during summer at stati...

Tentorial herniation is caused by a pressure gradient between supra and infratentorial compartments and the herniated brain is burdened with a force, which is called shear strain at the edge of the tentorium. The purpose of the present study is to clarify the relationships between increased intracranial pressure, the pressure gradient and the tentorial shear strain. Twenty-three monkeys were us...

This paper documents the exploration significance of Ag/Au, Au/Cu, Cu/Mo and (Ag×Au)/Cu×Mo) ratios of the supra-ore and sub-ore halos versus fluid inclusion evolution for 24 Cu, 6 Cu- Mo and 10 Cu-Au porphyry deposits worldwide. The ratios are based only on the economic and mineralized hypogene alteration zones. The results indicate that (Ag×Au)/(Cu×Mo), Au/Cu and Cu/Mo ratios increase with dec...

This paper presents a numerical simulation of the flow characteristics through a patient-specific model of an aortic coarctation. The purpose of the study was to predict the pressure gradient at rest and at exercise conditions. The commercial package ADINA was used to numerically solve the governing equations using finite-elements methods. The model was based on the patient's MR angiography dat...

In this paper the results of a leaching kinetics study of bauxite ore with sodium hydroxide are presented. The effect of ore particle size, sodium hydroxide concentration and reaction temperature on the Al2O3 extraction rate was determined. The results obtained showed that 99% of Al2O3 was leached out using -200+270 mesh ore particle size at a reaction temperature of 105 °C for 60 min reaction ...