Track Reconstruction and Performance of DRIFT Directional Dark Matter Detectors using Alpha Particles

First results are presented from an analysis of data from the DRIFT-IIa and DRIFT-IIb directional dark matter detectors at Boulby Mine in which alpha particle tracks were reconstructed and used to characterise detector performance--an important step towards optimising directional technology. The drift velocity in DRIFT-IIa was [59.3 +/- 0.2 (stat) +/- 7.5 (sys)] m/s based on an analysis of naturally-occurring alpha-emitting background. The drift velocity in DRIFT-IIb was [57 +/- 1 (stat) +/- 3 (sys)] m/s determined by the analysis of alpha particle tracks from a Po-210 source. 3D range reconstruction and energy spectra were used to identify alpha particles from the decay of Rn-222, Po-218, Rn-220 and Po-216. This study found that (22 +/- 2)% of Po-218 progeny (from Rn-222 decay) are produced with no net charge in 40 Torr CS2. For Po-216 progeny (from Rn-220 decay) the uncharged fraction is (100 +0 -35)%.Comment: 27 pages, 12 figures, 5 tables. Submitted to Nuclear Instruments and Methods in Physics Research, Section A. Subj-class: Instrumentation and Detector

Stereoconvergent synthesis of C-9 to C-16 fragment of trienomycin based on the regioselective opening of γ-δ-poxy acrylates with Trimethylaluminium

The C-9 to C-16 fragment, a key intermediate for the synthesis of a 21 membered ansamycin antibiotic, Trienomycin has been synthesized, involving Sharpless asymmetric epoxidation and the key stereoselective methylation of γ-δ-epoxy acrylates by Trimethylaluminium

Thermal Stability and Flammability of Epoxy Composites Filled with Multi-Walled Carbon Nanotubes, Boric Acid, and Sodium Bicarbonate

Epoxy composites filled with 0.5 wt% of multi-walled carbon nanotubes (MWCNTs), 10 and 15 wt% of boric acid and sodium bicarbonate separately, as well as composites filled with a combination of MWCNTs-boric acid and MWCNTs-sodium bicarbonate were prepared. The thermal behavior of the prepared samples was investigated under heating in oxidative environment using thermogravimetric analysis. The hardness was measured using the Shore D hardness test. To evaluate the flammability of the samples, the ignition temperature and time-to-ignition were determined. It was concluded that sodium bicarbonate in the studied concentrations (10 and 15 wt%) is not appropriate for use as a filler capable of improving the thermooxidative stability and reducing the flammability of epoxy polymers. The improvement in the thermal properties can be achieved by using the combination of boric acid and multi-walled carbon nanotubes as fillers. The thermooxidative destruction of the samples filled with boric acid passes more slowly and more evenly via the formation of B2O3 as a result of its decomposition

Synthesis and in vitro antiproliferative activity of diphenyl(sulphonylpiperidin-4-yl)methanol derivatives

10.1007/s00044-009-9186-8Medicinal Chemistry Research193220-235MCRE