RESUMEN
We present a new instrument, "Boreas", a cryogen-free methane (CH4) preconcentration system coupled to a dual-laser spectrometer for making simultaneous measurements of δ13C(CH4) and δ2H(CH4) in ambient air. Excluding isotope ratio scale uncertainty, we estimate a typical standard measurement uncertainty for an ambient air sample of 0.07 for δ13C(CH4) and 0.9 for δ2H(CH4), which are the lowest reported for a laser spectroscopy-based system and comparable to isotope ratio mass spectrometry. We trap CH4 (â¼1.9 µmol mol-1) from â¼5 L of air onto the front end of a packed column, subsequently separating CH4 from interferences using a controlled temperature ramp with nitrogen (N2) as the carrier gas, before eluting CH4 at â¼550 µmol mol-1. This processed sample is then delivered to an infrared laser spectrometer for measuring the amount fractions of 12CH4, 13CH4, and 12CH3D isotopologues. We calibrate the instrument using a set of gravimetrically prepared amount fraction primary reference materials directly into the laser spectrometer that span a range of 500-626 µmol mol-1 (CH4 in N2) made from a single pure CH4 source that has been isotopically characterized for δ13C(CH4) by IRMS. Under the principle of identical treatment, a compressed ambient air sample is used as a working standard and measured between air samples, from which a final calibrated isotope ratio is calculated. Finally, we make automated measurements of both δ13C(CH4) and δ2H(CH4) in over 200 ambient air samples and demonstrate the application of Boreas for deployment to atmospheric monitoring sites.
RESUMEN
The data presented in this article is related to the research article entitled "Fabrication of air-stable, large-area, PCDTBT:PC70BM polymer solar cell modules using a custom built slot-die coater" (D.I. Kutsarov, E. New, F. Bausi, A. Zoladek-Lemanczyk, F.A. Castro, S.R.P. Silva, 2016) [1]. The repository name and reference number for the raw data from the abovementioned publication can be found under: https://doi.org/10.15126/surreydata.00813106. In this data in brief article, additional information about the absorption properties of PCDTBT:PC70BM layers deposited from a 12.5 mg/ml and 15 mg/ml photoactive layer dispersion are shown. Additionally, the best and average J-V curves of single cells, fabricated from the 10 and 15 mg/ml dispersions, are presented.
RESUMEN
This paper presents new experimental results on a polymer light-emitting diode based visible light communications system. For the first time we demonstrate a 10 Mb/s link based on the on-off keying data format with real time equalization on a field programmable gate array. The 10 Mb/s transmission speed is available at a bit error rate less than 4.6 × 10(-3), which is the limit for forward error correction. At a BER of 10(-6) a transmission speed of 7 Mb/s is readily achievable.
RESUMEN
The influence of a new comb-shaped polycarboxylate-based superplasticizer (CSSP) on the hydration kinetics and transport properties of aged cement pastes has been investigated by high-resolution quasi-elastic neutron scattering (QENS) and low temperature differential scanning calorimetry (LT-DSC). A new method of analysis of QENS spectra is proposed. By applying the refined method we were able to access to four independent physical parameters including the self-diffusion coefficient of the hydration water confined in the cement paste. Mean squared displacement (MSD) of the hydrogen atom for mobile water molecules displays a dynamic crossover temperature in agreement with DSC data. The experimental results indicate that CSSP polymer added into cement paste moderates the hydration process and decreases the dynamic crossover temperature of the hydration water.