Rapid method to determine 89/90Sr in steel samples

The sorption and diffusion behavior of cesium was studied to support the interpretation of the ongoing in-situ experiments in the Olkiluoto test site. The distribution coefficients of cesium in the Olkiluoto pegmatitic granite, veined gneiss and their main minerals were obtained by batch sorption experiments and the diffusion of cesium was studied in rock cubes. The results were modelled with PHREEQC and Comsol Multiphysics. The distribution coefficients of cesium were largest in biotite and veined gneiss. The effective diffusion coefficients of cesium from the diffusion model were 3 × 10⁻¹³ m² s⁻¹ for veined gneiss and 4 × 10⁻¹³ m² s⁻¹ for pegmatitic granite.

     

Influence of the solvent quality on the AhR mediated Procept assay measurement of dioxin and dioxin-like compounds

Polychlorodibenzo-p-dioxins, polychorodibenzofurans and “dioxin-like” polychlorinated biphenyls are widespread persistent organic pollutants sharing a similar toxicological pathway mediated by the aryl-hydrocarbon receptor (AhR). Since the confirmatory method for their measurement at trace levels in complex matrices (using isotopic dilution and gas chromatography-high resolution mass spectrometry) remains time and cost-consuming, growing efforts of the scientific community have been focused on the development of screening approaches, including AhR mediated assays. Unfortunately, AhR ligands are highly diverse and agonistic/antagonistic effects can be observed on procedural blanks and/or sample extracts. In this study, the influence of solvent grade quality on the response of a DNA-binding AhR mediated assay used for screening dioxins has been investigated. Our results demonstrated a very critical impact of this parameter with both strong agonistic and antagonistic effects observed for any tested solvent lot. A small silver nitrate silica column removed partly these interfering compounds and then can be recommended as final purification step. Some preferable grades can be identified and selected in order to guarantee the best possible performances. However, it appears necessary to test every new lot, even if a grade appeared previously compliant.     

On the interpretation of the electrical resistance of disordered materials

We use recursion relations due to Shapiro [1] to construct a “phase diagram” which illustrates the occurence of classical and quantum insulation, and metallic behaviour in disordered materials from 1D to 6D. We show that this diagram is useful in discussing and understanding experimental data.     

Electrical conduction in sputtered Si:Al films

The d.c. electrical resistivity ?(x, T) has been measured for a series of granular Si_xAl_1?x sputtered films for 0.25 < x < 0.62 and 4K < T < 300 K. Three separate behaviours are identified in ?(x, T) corresponding to extrinsic activated semiconduction, metallic conduction and electron localisation.     

Recording and evaluation methods of PIV investigations on a helicopter rotor model

Three-component particle image velocimetry measurements at moderate speeds and observation distances can now be accomplished on a routine basis. This article discusses the experiment performed on a 4 m-diameter model rotor in the 6-m×8-m open test section of the Large Low Speed Facility of the German–Dutch Wind Tunnels. More than half a terabyte of raw data were recorded at various positions on the advancing and retreating sides of the rotor in order to obtain detailed measurements of the trailing vortex in the frame of an international project. This paper addresses measuring techniques and possible sources of errors and presents a limited number of cases for the purpose of illustrating the solutions to numerous technical challenges relating to the acquisition and analysis of vortical flows.List of symbols C _T thrust coefficient (T/² R ⁴) - M magnification - r _c radius of vortex core (mm) - R rotor radius (m) - T thrust (N) - u,v,w velocity components in x, y and z coordinates (m/s) - (u,v,w)_wt velocity components in wind tunnel coordinates (m/s) - U _max maximum in-plane velocity component (m/s) - W _max maximum out-of-plane velocity component (m/s) - x,y,z particle image velocimetry (PIV) frame coordinates (m) - (x,y,z)_wt wind tunnel coordinates (m) - t time delay (s) - Z light sheet thickness (mm) - Z light sheet thickness (mm) - rotor rotation frequency (rad/s) - rotor azimuth angle during recording (deg) vortex age - rotor shaft angle (deg) - _x displacement measurement error - advance ratio (V/R) - air density (kg/m³) - circulation (m²/s) - _z vorticity (s^–1) Abbreviations AFDD Aeroflightdynamics Directorate - BVI blade–vortex interaction - DLR Deutches zentrum für Luft- und Raumfahrt - DNW German–Dutch Wind tunnel - HART HHC aeroacoustic rotor test - LLF large low speed facility - NASA National Aeronautics and Space Administration - ONERA Office National dEtudes e de Recherches Aerospatiales - RANS Reynolds-averaged Navier–Stokes - SPR stereo pattern recognition - 3C-PIV three-component particle image velocimetry     

Spectrophotometric determination of inorganic phosphate in soil extracts by a single-solution non-reductive method

A previous method involving crystal violet—12-molybdophosphate formation is modified by including all reagents into a single solution. The apparent molar absorptivity is 0.84 × 10⁵ l mol^-1 cm^-1. The results obtained for a series of soil extracts correlate well with those obtained by a reductive method.