Physicochemical characteristics of gamma irradiation crosslinked poly(vinyl alcohol)/magnetite ferrogel composite

Magnetic field sensitive gels, ferrogels, are new promising class of hydrogels. The coupling of hydrogels and magnetic particles has potential application in soft actuators, such as artificial muscles, or for hyperthermia application. In this study, the composite of magnetite particles (Fe3O4) and poly(vinyl alcohol) (PVA) hydrogel is developed using gamma irradiation as a crosslinking agent. PVA and Fe3O4 were chosen due to their well-established biocompatibility, radiation crosslinking potential (PVA), mild magnetic properties and the Curie point near desired heating temperature range (Fe3O4). Physicochemical characteristics of these systems show the effect of the presence of particles in the process of radiation-induced crosslinking. Obtained PVA/Fe3O4 ferrogel composite has greater swelling capacity, activation energy of dehydration and dehydration rate compared to PVA hydrogel, crosslinked under the same conditions

Electroanalytical Sensing of Bromides Using Radiolytically Synthesized Silver Nanoparticle Electrocatalysts

Monitoring bromides (Br-) is of crucial importance since bromates, potential human carcinogens, are formed during ozonation of water containing bromides in concentrations GT 100 mu gL(-1). Within this study, silver (Ag) and four carbon-supported Ag catalysts were synthesized by the gamma-radiation method and their morphology and structure examined using transmission electron microscopy, X-ray diffraction, and UV-Vis analysis. The nanocatalysts were tested for Br- sensing in aqueous media using cyclic voltammetry. All five Ag materials exhibited electroactivity for sensing of Br- ions, with pure Ag catalyst giving the best response to Br- ions presence in terms of the lowest limit of detection. Sensing of bromides was also explored in tap water after addition of bromides suggesting that herein prepared catalysts could be used for bromides detection in real samples. Furthermore, sensing of other halogen ions, namely, chlorides and iodides, was examined, and response due to chloride presence was recorded

Search for W - GT t(b)over-bar in the lepton plus jets final state in proton-proton collisions at a centre-of-mass energy of root s=8 TeV with the ATLAS detector

A search for new charged massive gauge bosons, called W, is performed with the ATLAS detector at the LHC, in proton-proton collisions at a centre-of-mass energy of root s = 8 TeV, using a dataset corresponding to an integrated luminosity of 20.3 fb(-1). This analysis searches for W bosons in the W - GT t (b) over tilde decay channel in final states with electrons or muons, using a multivariate method based on boosted decision trees. The search covers masses between 0.5 and 3.0 TeV, for right-handed or left-handed W bosons. No significant deviation from the Standard Model expectation is observed and limits are set on the W - GT t (b) over bar cross-section times branching ratio and on the W-boson effective couplings as a function of the W-boson mass using the CLs procedure. For a left-handed (right-handed) W boson, masses below 1.70 (1.92) TeV are excluded at 95% confidence level. Published by Elsevier B.V

Search for dark matter in events with heavy quarks and missing transverse momentum in pp collisions with the ATLAS detector

This article reports on a search for dark matter pair production in association with bottom or top quarks in 20.3 fb(-1) of pp collisions collected at root s = 8 TeV by the ATLAS detector at the LHC. Events with large missing transverse momentum are selected when produced in association with high-momentum jets of which one or more are identified as jets containing b-quarks. Final states with top quarks are selected by requiring a high jet multiplicity and in some cases a single lepton. The data are found to be consistent with the Standard Model expectations and limits are set on the mass scale of effective field theories that describe scalar and tensor interactions between dark matter and Standard Model particles. Limits on the dark-matter-nucleon cross-section for spin-independent and spin-dependent interactions are also provided. These limits are particularly strong for low-mass dark matter. Using a simplified model, constraints are set on the mass of dark matter and of a coloured mediator suitable to explain a possible signal of annihilating dark matter

Search for new phenomena in events with a photon and missing transverse momentum in pp collisions at root s = 8 TeV with the ATLAS detector

Results of a search for new phenomena in events with an energetic photon and large missing transverse momentum with the ATLAS experiment at the LHC are reported. Data were collected in proton-proton collisions at a center-of-mass energy of 8 TeVand correspond to an integrated luminosity of 20.3 fb(-1). The observed data are well described by the expected Standard Model backgrounds. The expected (observed) upper limit on the fiducial cross section for the production of events with a photon and large missing transverse momentum is 6.1 (5.3) fb at 95% confidence level. Exclusion limits are presented on models of new phenomena with large extra spatial dimensions, supersymmetric quarks, and direct pair production of dark-matter candidates

Search for a standard model Higgs boson in the H - GT ZZ - GT l(+)l(-) nu(nu)over-bar decay channel using 4.7 fb(-1) of root s=7 TeV data with the ATLAS detector

A search for a Standard Model Higgs boson decaying via H - GT ZZ - GT l(+)l(-) nu(nu) over bar, where l represents electrons or muons, is presented. It is based on proton-proton collision data at root s = 7 TeV, collected by the ATLAS experiment at the LHC during 2011 and corresponding to an integrated luminosity of 4.7 fb(-1). The data agree with the expected Standard Model backgrounds. Upper limits on the Higgs boson production cross section are derived for Higgs boson masses between 200 GeV and 600 GeV and the production of a Standard Model Higgs boson with a mass in the range 319-558 GeV is excluded at the 95% confidence level. (C) 2012 CERN. Published by Elsevier B.V. All rights reserved

Search for the b(b)over-bar decay of the Standard Model Higgs boson in associated (W/Z)H production with the ATLAS detector

A search for the b (b) over bar decay of the Standard Model Higgs boson is performed with the ATLAS experiment using the full dataset recorded at the LHC in Run 1. The integrated luminosities used are 4.7 and 20.3 fb(-1) from pp collisions at root s = 7 and 8 TeV, respectively. The processes considered are associated (WIZ)H production, where W - GT e nu/mu nu, Z - GT ee/mu mu, and Z - GT nu nu. The observed (expected) deviation from the backgroundonly hypothesis corresponds to a significance of 1.4 (2.6) standard deviations and the ratio of the measured signal yield to the Standard Model expectation is found to be mu = 0.52 +/- 0.32 (stat.) +/- 0.24 (syst.) for a Higgs boson mass of 125.36 GeV. The analysis procedure is validated by a measurement of the yield of (W/Z)Z production with Z - GT b (b) over bar in the same final states as for the Higgs boson search, from which the ratio of the observed signal yield to the Standard Model expectation is found to be 0.74 +/- 0.09 (stat.) +/- 0.14 (syst.)

Search for the Standard Model Higgs boson produced in association with top quarks and decaying into in collisions at with the ATLAS detector

A search for the Standard Model Higgs boson produced in association with a top-quark pair, , is presented. The analysis uses 20.3 fb(-1) of pp collision data at , collected with the ATLAS detector at the Large Hadron Collider during 2012. The search is designed for the decay mode and uses events containing one or two electrons or muons. In order to improve the sensitivity of the search, events are categorised according to their jet and b-tagged jet multiplicities. A neural network is used to discriminate between signal and background events, the latter being dominated by +jets production. In the single-lepton channel, variables calculated using a matrix element method are included as inputs to the neural network to improve discrimination of the irreducible background. No significant excess of events above the background expectation is found and an observed (expected) limit of 3.4 (2.2) times the Standard Model cross section is obtained at 95 % confidence level. The ratio of the measured signal cross section to the Standard Model expectation is found to be assuming a Higgs boson mass of 125 Gev

Measurement of the inclusive isolated prompt photon cross section in pp collisions at root s=7 TeV with the ATLAS detector

A measurement of the cross section for the inclusive production of isolated prompt photons in pp collisions at a center-of-mass energy root s = 7 TeV is presented. The measurement covers the pseudorapidity ranges vertical bar eta(gamma)vertical bar LT 1: 37 and 1: 52 LT = vertical bar eta(gamma)vertical bar LT 1: 81 in the transverse energy range 15 LT = E-T(gamma) LT 100 GeV. The results are based on an integrated luminosity of 880 nb(-1), collected with the ATLAS detector at the Large Hadron Collider. Photon candidates are identified by combining information from the calorimeters and from the inner tracker. Residual background in the selected sample is estimated from data based on the observed distribution of the transverse isolation energy in a narrow cone around the photon candidate. The results are compared to predictions from next-to-leading-order perturbative QCD calculations

Search for New Phenomena in Dijet Angular Distributions in Proton-Proton Collisions at root s=8 TeV Measured with the ATLAS Detector

A search for new phenomena in LHC proton-proton collisions at a center-of-mass energy of root s = 8 TeV was performed with the ATLAS detector using an integrated luminosity of 17.3 fb(-1). The angular distributions are studied in events with at least two jets; the highest dijet mass observed is 5.5 TeV. All angular distributions are consistent with the predictions of the standard model. In a benchmark model of quark contact interactions, a compositeness scale below 8.1 TeV in a destructive interference scenario and 12.0 TeV in a constructive interference scenario is excluded at 95% C.L.; median expected limits are 8.9 TeV for the destructive interference scenario and 14.1 TeV for the constructive interference scenario