1,988 research outputs found
Towards a standardization of biomethane potential tests
Production of biogas from different organic materials is a most interesting source of renewable energy.
The biomethane potential (BMP) of these materials has to be determined to get insight in design
parameters for anaerobic digesters. Although several norms and guidelines for BMP tests exist,
inter-laboratory tests regularly show high variability of BMPs for the same substrate. A workshop was
held in June 2015, in Leysin, Switzerland, with over 40 attendees from 30 laboratories around the world,
to agree on common solutions to the conundrum of inconsistent BMP test results. This paper presents
the consensus of the intense roundtable discussions and cross-comparison of methodologies used in
respective laboratories. Compulsory elements for the validation of BMP results were defined. They
include the minimal number of replicates, the request to carry out blank and positive control assays, a
criterion for the test duration, details on BMP calculation, and last but not least criteria for rejection of
the BMP tests. Finally, recommendations on items that strongly influence the outcome of BMP tests
such as inoculum characteristics, substrate preparation, test setup, and data analysis are presented to
increase the probability of obtaining validated and reproducible results.info:eu-repo/semantics/publishedVersio
First results from the AX-PET demonstrator
The AX-PET demonstrator is based on a new concept in PET detectors, with LYSO crystals aligned along the z coordinate (patient's axis) and WLS (Wave-length shifter) strips placed orthogonal to them. This kind of structure permits to avoid parallax errors due to different depths of interaction of the photons in the crystals, to register the three coordinates of the impinging photon and to reconstruct Compton events. In this way both the spatial resolution and the sensitivity can be highly improved. Moreover, as both the LYSO crystals and the strips are readout via Geiger-mode Avalanche Photo Diodes (G-APDs) the detector is insensitive to magnetic fields and is then suitable to be used in a combined PET/MRI apparatus. A complete Monte Carlo simulation and dedicated reconstruction software, suited to the particular geometry arrangement, have been developed. The two final modules, each composed by 48 crystals and 156 WLS strips have been built and fully characterized in a dedicated test set-up. The results on the performances of the system obtained with a 22Na point source (0.25 mm diameter) are reported
Energy Resolution Performance of the CMS Electromagnetic Calorimeter
The energy resolution performance of the CMS lead tungstate crystal electromagnetic calorimeter is presented. Measurements were made with an electron beam using a fully equipped supermodule of the calorimeter barrel. Results are given both for electrons incident on the centre of crystals and for electrons distributed uniformly over the calorimeter surface. The electron energy is reconstructed in matrices of 3 times 3 or 5 times 5 crystals centred on the crystal containing the maximum energy. Corrections for variations in the shower containment are applied in the case of uniform incidence. The resolution measured is consistent with the design goals
Search for R-Parity Breaking Sneutrino Exchange at LEP
We report on a search for R--parity breaking effects due to supersymmetric tau--sneutrino exchange in the reactions e+e- to e+e- and e+e- to mu+mu- at centre--of--mass energies from 91~{\GeV} to 172~{\GeV}, using the L3 detector at LEP. No evidence for deviations from the Standard Model expectations of the measured cross sections and forward--backward asymmetries for these reactions is found. Upper limits for the couplings and for sneutrino masses up to m_{\SNT} \leq 190~\GeV are determined from an analysis of the expected effects due to tau sneutrino exchange
Search for neutral B meson decays to two charged leptons
The decays are searched for in 3.5 million hadronic events, which constitute the full LEP I data sample collected by the L3 detector. No signals are observed, therefore upper limits at the 90\%(95\%) confidence levels are set on the following branching fractions: % \begin{center}% {\setlength{\tabcolsep}{2pt} \begin{tabular}{lccccclcccc}% % Br & & & & ; & \hspace*{5mm} & Br & & & & ; \\% Br & & & & ; & \hspace*{5mm} & Br & & & & ; \\% Br & & & & ; & \hspace*{5mm} & Br & & & & . \\% % \end{tabular}% } \end{center}% % The results for and are the first limits set on these decay modes
Study of the Weak Charged Hadronic Current in b Decays
Charged and neutral particle multiplicities of jets associated with identified semileptonic and hadronic b decays are studied. The observed differences between these jets are used to determine the inclusive properties of the weak charged hadronic current. The average charged particle multiplicity of the weak charged hadronic current in b decays is measured for the first time to be 2.690.07(stat.)0.14(syst.). This result is in good agreement with the JETSET hadronization model of the weak charged hadronic current if 4017\% of the produced mesons are light--flavored tensor (L=1) mesons. This level of tensor meson production is consistent with the measurement of the multiplicity in the weak charged hadronic current in b decays. \end{abstract
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