Absolute cross sections for electron scattering from furan

We report results of measurements and calculations of absolute cross sections for electron scattering from furan molecules (C 4H 4O). The experimental absolute differential cross sections (DCSs) for elastic electron scattering were obtained for the incident energies from 50 eV to 300 eV and for scattering angles from 20 to 110, by using a crossed electron-target beam setup and the relative flow technique for calibration to the absolute scale. The calculations of the electron interaction cross sections are based on a corrected form of the independent-atom method, known as the screening corrected additivity rule (SCAR) procedure and using an improved quasifree absorption model. The latter calculations also account for rotational excitations in the approximation of a free electric dipole and were used to obtain elastic DCSs as well as total and integral elastic cross sections which are tabulated in the energy range from 10 to 10 000 eV. All SCAR calculated cross sections agree very well with both the present and previously published experimental results. Additionally, calculations based on the first Born approximation were performed to calculate both elastic and vibrationally inelastic DCSs for all the modes of furane, in the energy range from 50 eV to 300 eV. The ratios of the summed vibrational to elastic DCSs are presented and discussed. Finally, the present results for furan are compared with previously published elastic DCSs for the tetrahydrofuran molecule and discussed. © 2012 American Institute of Physics.American Institute of Physics#Supported by the Ministry of Education and Science of Republic of Serbia (Project No. 171020) and Spanish Ministerio de Ciencia e Innovación Project No. FIS2009-10245, and motivated by the COST Action MP1002 (Nano-IBCT). R.C. acknowledges support of the Czech Ministry of Education (Grant No. OC10046) and the Grant Agency of the Czech Republic (Grant No. P208/11/0452).Peer Reviewe

Measuring exposure of e-waste dismantlers in Dhaka Bangladesh to organophosphate esters and halogenated flame retardants using silicone wristbands and T-shirts

Silicone (polydimethylsiloxane or PDMS) wristbands and cotton T-shirts were used to assess the exposure of e-waste recyclers in Dhaka, Bangladesh to polybrominated diphenyl ethers (PBDEs), novel brominated flame retardants (NBFRs), dechlorane plus (DPs), and organophosphate esters (OPEs). The median surface-normalized uptake rates of PBDEs, NBFRs, DPs, and OPEs were 170, 8.5, 4.8, and 270 ng/dm/h for wristbands and 5.4, 2.0, 0.94, and 23 ng/dm/h for T-shirts, respectively. Concentrations of Tris(2-chloroethyl) phosphate (TCEP), Tris(1,3-dichloro-2-propyl) phosphate (TDCIPP), Tri-m-cresyl phosphate (TmCP), Bis(2-ethlyhexyl) tetrabromophthalate (BEH-TEBP), and Dechlorane plus (DPs) in wristbands were significantly correlated with those in T-shirts. Wristbands accumulated ~7 times more mass than T-shirts, especially of compounds expected to be mainly in the gas phase. We introduce the silicone “sandwich” method to approximate the easily releasable fraction (ERF) from T-shirts, hypothesized to be related to dermal exposure. ERFs varied from 6 to 75% of total chemical accumulated by T-shirts and were significantly negatively correlated with compounds' octanol-air partition coefficient (log K). The median daily exposure doses via dermal transfer from the front of the T-shirt to the front body trunk were 0.32, 0.13, 0.11, and 9.1 ng/kg-BW/day for PBDEs, NBFRs, DPs, and OPEs, respectively. The evidence of e-waste recycler exposure to flame retardants in this low income country, lacking protective personal equipment, calls for measures to minimize their exposure and for chemical management regulations to consider exposures to chemicals in waste products.This study was supported by IIE Centennial Fellowship, Connaught Early Researcher Award, NSERC Discovery Grant (RGPIN-2018-06185) to Syed Ishtiaque Ahmed; European Union Horizon 2020 funding of “INTERWASTE” (Grant Agreement 734522) that supported Andrea Peris; and NSERC Discovery grant (RGPIN-2017-06654) to Miriam Diamond. Yan Wang gratefully acknowledges the financial support from China Scholarship Council (201806065027). We thank Adriana Shu-Yin for preparing sampling materials, and Dr. Nafisa Islam, Mr. Ehsanur Rahman, and Ms. Marfua Mowla from Bangladesh University of Engineering and Technology (BUET) for their help in conducting the wristband and T-shirt exposure experiments with the e-waste workers in Dhaka, Bangladesh