Effective Precipitation of Arsenic from Aqueous Solution by Iron(III) Sulfate

A study of the removal of As(V) from aqueous solution by Fe₂(SO₄)₃ has been carried out to establish optimum parameters for the process. Optimum arsenic removal is obtained at pH = 5, and mole ratio Fe(III)/As(V) = 7. Minimum arsenate solubility is obtained from sediments precipitated at pH = 5 and Fe/As = 7…8.     

Palynological evidence for Pennsylvanian (Late Carboniferous) vegetation change in the Sydney Coalfield,eastern Canada

The palynology of clastic samples from seven stratigraphical levels in the late Moscovian Sydney Mines Formation, exposed along the shore at Bras d'Or, Nova Scotia, has been investigated. Most of the samples were from roof shales of major coals; the one sample that was not yielded a much higher proportion of pollen derived from extra‐basinal vegetation. The four stratigraphically lower roof shale samples yielded essentially similar palynological spectra, with 39 ± 4% lycophytes, 9 ± 4% sphenophylls, 23 ± 4% tree‐ferns, 12 ± 4% other ferns and 5 ± 3% cordaites. The palynology of the upper part of the investigated succession suggests a shift in vegetation towards one favouring more marattialean tree‐ferns, cordaites and conifers, and fewer lycophytes. This correlates with changes in drainage patterns as the alluvial plain migrated seawards and thus changed water tables. No evidence was found to suggest significant climate change at this time. Copyright © 2009 John Wiley & Sons, Ltd.     

Influence of Thermal Effects on the Wind Field Within the Urban Environment

Micrometeorological conditions in the vicinity of urban buildings strongly influence the requirements that are imposed on building heating and cooling. The goal of the present study, carried out within the Advance Tools for Rational Energy Use towards Sustainability (ATREUS) European research network, is the evaluation of the wind field around buildings with walls heated by solar radiation. Two computational fluid dynamics (CFD) codes were validated against extensive wind-tunnel observations to assess the influence of thermal effects on model performance. The code selected from this validation was used to simulate the wind and temperature fields for a summer day in a specific region of the city of Lisbon. For this study, the meteorological data produced by a non-hydrostatic mesoscale atmospheric model (MM5) were used as boundary conditions for a CFD code, which was further applied to analyze the effects of local roughness elements and thermodynamic conditions on the air flow around buildings. The CFD modelling can also provide the inflow parameters for a Heating, Ventilation and Air Conditioning (HVAC) system, used to evaluate the building energy budgets and to predict performance of the air-conditioning system. The main finding of the present three-dimensional analyses is that thermal forcing associated with the heating of buildings can significantly modify local properties of the air flow.     

Solar and geomagnetic activity effects on heart rate variability

Investigation into possible space weather hazards on cardiovascular system has been performed. A group of 14 healthy volunteers was examined in the spring of 2009 and 2 healthy persons performed electrocardiograph records for a period of 1 year everyday in the morning and in the evening. Results revealed that heart rate variability (HRV) parameters of the group varied strongly from the day before till 3 days after the registered weak storms during the time of investigation. Blood pressure and subjective psychophysiological complaints increased statistically significantly from 0 day till +2nd day. Heart rate (HR) of the group showed a trend for decrease. It was established that morning measurements were more sensitive to space weather variations in comparison with evening measurements. Both persons with prolonged registrations for a period of year did not reveal graded response to geomagnetic storms with different intensities. Both of them decreased HR during moderate storms, but they increased HR during major storms and on the days before and after these storms. HRV parameters varied significantly on these days.     

Observations of PC5 pulsations near field-aligned current regions

Examples of long period Pc5 magnetic field pulsations near field-aligned current (FAC) regions in the high-latitude magnetosphere, observed by INTERBALL-Auroral satellite during January 11, April 11 and June 28, 1997 are shown. Identification of corresponding magnetosphere regions and subregions is provided by electrons and protons in the energy-range of 0.01–100 keV measured simultaneously onboard the spacecraft. The examined Pc5 pulsations reveal a compressional character. A fairly good correlation is demonstrated between these ULF Pc5 waves and the consecutive injection of magnetosheath low energy protons. The ULF Pc5 wave occurrence is observed in both upward and downward FACs.     

Simulations of Coastal Fog in the Canadian Atlantic with the Weather Research and Forecasting Model

Boundary-Layer Meteorology - We evaluate the efficacy of microphysics and planetary-boundary-layer (PBL) parametrizations of the Weather Research and Forecasting (WRF) model for simulation of the...     

Deep Structure and Dynamics of the Central Balkan Peninsula from Seismic Data

Izvestiya, Physics of the Solid Earth - Abstract—Analysis of P- and S-receiver functions for 19 seismic stations on the Balkan Peninsula has been performed. Half of the stations are in...     

Homogenization of the transport behavior of nonlinearly adsorbing pollutants in physically and chemically heterogeneous aquifers

This paper addresses the question of how spatial variability in the hydraulic and chemical properties of groundwater systems affects the transport and sorption behavior of pollutants at the field scale. In this paper, we limit our investigations on pollutants that adsorb according to an equilibrium controlled nonlinear Freundlich sorption isotherm. The new contribution of this paper is take into account not only spatially variable Freundlich distribution coefficients _KS$K_S$ but spatially variable Freundlich nonlinearity parameters p as well. Using a homogenization theory approach, we shortly review the impact of spatially variable hydraulic properties on the transport and extend the theory to spatially variable chemical properties. We show that spatially variable Freundlich exponents cause a very different field scale transport and sorption behavior than spatial variations in the distribution coefficients only since in the first case field scale Freundlich parameters and field scale dispersion coefficients become concentration dependent. In particular, field scale retardation is much larger than small-scale retardation.     

Undrained Strength of Deposited Mine Tailings Beds: Effect of Water Content, Effective Stress and Time of Consolidation

An understanding of the geotechnical behaviour of mine tailings is imperative when evaluating the stability and erosional resistance of sedimented tailings beds; as well as for the design and long-term management of tailings disposal facilities. Laboratory testing was conducted on mine tailings beds of various ages and thicknesses, deposited from concentrated slurries. Measured index properties allowed classifying the tailings as a coarse grained and non-cohesive material. The results obtained from the performed sedimentation experiments showed that the primary consolidation of the tailings beds was complete in approximately 1 h and negligible volume changes occurred in the beds during secondary compression. The undrained shear strength of the tailings beds was measured using an automated fall cone device at a depth interval of 1 cm and a profile of the shear strength variation with depth was obtained. At each tested surface, moisture content specimens were taken to determine the moisture content profile of the tested tailings beds. The undrained shear strength of the beds varied between 0.008 and 0.975 kPa for effective stresses below 1.19 kPa and increased with depth. Correspondingly, the moisture content decreased with depth and varied between 17 and 27%. The factor controlling the undrained shear strength of the tested beds was the vertical effective stress, with the water content also having some secondary effect. The correlation between the undrained shear strength and the vertical effective stress was expressed with a second order polynomial function. Consolidation time did not appear to influence the observed shear strength.