Low‐temperature crystallization of La0.15Sr0.775TiO3 using ionic liquids

The n‐type thermoelectric oxide La0.15Sr0.775TiO3 (LST) has been synthesized at 600°C using an ionic liquid method. The method uses the ionic liquid 1‐ethyl 3‐methylimidazolium acetate as the sole complexing agent: the lack of a second, carbon‐rich template decreases the quantity of reduced intermediate phases which form during heating. By suppressing these phases, greatly reduced temperatures can be used to crystallize the perovskite LST phase, on the nanoscale. These nanoparticles have the potential to be used to increase the figure of merit in n‐type thermoelectric oxide devices

Uncharted waters: the unintended impacts of residual chlorine on water quality and biofilms

Disinfection residuals in drinking water protect water quality and public heath by limiting planktonic microbial regrowth during distribution. However, we do not consider the consequences and selective pressures of such residuals on the ubiquitous biofilms that persist on the vast internal surface area of drinking water distribution systems. Using a full scale experimental facility, integrated analyses were applied to determine the physical, chemical and biological impacts of different free chlorine regimes on biofilm characteristics (composition, structure and microbiome) and water quality. Unexpectedly, higher free chlorine concentrations resulted in greater water quality degredation, observable as elevated inorganic loading and greater discolouration (a major cause of water quality complaints and a mask for other failures). High-chlorine concentrations also reduced biofilm cell concentrations but selected for a distinct biofilm bacterial community and inorganic composition, presenting unique risks. The results challenge the assumption that a measurable free chlorine residual necessarily assures drinking water safety

Xanthan gum as a water-based binder for P3-Na2/3Ni1/3Mn2/3O2

P3-Na2/3Ni1/3Mn2/3O2 (P3-NNM) is a promising cathode material for Na-ion batteries, although large volume expansions during cycling mean that challenges around suitable binders still remain. This study reports the use of xanthan gum as a water-soluble, easy to handle, and sustainable biopolymer binder in conjunction with a P3-Na2/3Ni1/3Mn2/3O2-positive electrode material. The conditions for recovering pristine P3-NNM powders, following water-based processing, are established, and the electrochemical performance of cells prepared using the xanthan gum binder are compared to the more traditional polyvinylidene fluoride. Comparable discharge capacities are observed regardless of the binder choice, at ca. 115 mA h g−1 (77 mAh g−1 after 50 cycles; 0.1 C between 2.0 and 4.2 V). The xanthan gum binder cells also show a similar rate capability and slightly higher capacities at faster c-rates vs. polyvinylidene fluoride, making xanthan gum a viable alternative to the traditional organic binders for water-stable cathode materials

In situ or ex situ synthesis for electrochemical detection of hydrogen peroxide—an evaluation of Co2SnO4/RGO nanohybrids

Nowadays, there is no doubt about the high electrocatalytic efficiency that is obtained when using hybrid materials between carbonaceous nanomaterials and transition metal oxides. However, the method to prepare them may involve differences in the observed analytical responses, making it necessary to evaluate them for each new material. The goal of this work was to obtain for the first time Co2SnO4 (CSO)/RGO nanohybrids via in situ and ex situ methods and to evaluate their performance in the amperometric detection of hydrogen peroxide. The electroanalytical response was evaluated in NaOH pH 12 solution using detection potentials of −0.400 V or 0.300 V for the reduction or oxidation of H2O2. The results show that for CSO there were no differences between the nanohybrids either by oxidation or by reduction, unlike what we previously observed with cobalt titanate hybrids, in which the in situ nanohybrid clearly had the best performance. On the other hand, no influence in the study of interferents and more stable signals were obtained when the reduction mode was used. In conclusion, for detecting hydrogen peroxide, any of the nanohybrids studied, i.e., in situ or ex situ, are suitable to be used, and more efficiency is obtained using the reduction mode

The Spinel LiCoMnO4: 5V cathode and conversion anode

LiCoMnO4 was made at 550 °C in 2 h using a novel biotemplating synthetic methodology. High temperature heat treatment under flowing N2 was then used to prepare the cation-disordered rock salt, LiCoMnO3. We demonstrate for the first time that both phases can operate as conversion anodes in lithium-ion batteries, operating at ~ 0.7 V with specific capacities of ~ 400 mAh g-1. We also demonstrate that 1,3-propane sultone can be used as an electrolytic additive to provide a modest boost to specific capacity in cells cycled at high potentials with LiCoMnO4 as the cathode

High temperature and ion implantation-induced phase transformations in novel reduced activation Si-Fe-V-Cr (-Mo) high entropy alloys

For fusion to be realized as a safe, sustainable source of power, new structural materials need to be developed which can withstand high temperatures and the unique fusion radiation environment. An attractive aspect of fusion is that no long-lived radioactive wastes will be produced, but to achieve this structural materials must comprise reduced activation elements. Compositionally complex alloys (CCAs) (also called high entropy alloys, HEAs) are promising candidates for use in extreme environments, including fusion, but few reported to date have low activation. To address these material challenges, we have produced novel, reduced activation, HEAs by arc-melting, and investigated their thermal stability, and radiation damage resistance using 5 MeV Au2+ ion implantation. Whilst the alloys were designed to form single phase BCC, using room temperature and non-ambient in situ X-ray diffraction we have revealed the thermodynamically stable structure of these alloys is in fact a sigma phase. We propose that a BCC phase is formed in these alloys, but at high temperatures (>1000°C). A BCC phase was also formed during heavy ion implantation, which we propose to be due to the rapid heating and cooling that occurs during the thermal spike, effectively freezing in the BCC phase produced by an implantation induced phase transformation. The BCC phase was found to have high hardness and a degree of ductility, making these new alloys attractive in the development of reduced activation HEAs for nuclear applications

Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal

Standalone vertex finding in the ATLAS muon spectrometer

A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

A measurement of the production cross-section for top quark pairs(\ttbar) in $pp$ collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron $e$ or muon $\mu$) with large missing transverse energy and at least four jets, and dilepton ($ee$, $\mu\mu$ or $e\mu$) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be $12.2 \pm 3.9$ events and $2.5 \pm 0.6$ events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde