Synergistic effect of acetic acid and NOXfor objects made of lead and its alloys; Indoor corrosive environments in museums and depositories

Complex corrosion simulation to evaluate synergistic effect have to cover large number of factors. To do so, environmental and corrosion datasets collected by monitoring sites of interest have been used to tailor complex artificial ageing of lead and lead alloys, using lead, tin and tin-lead coupons. Material composition was based on objects of interest which are tin-lead alloy based although naming lead objects is used widespread for vast of them. To evaluate results corrosion rate based on weight loss, phase composition of corrosion product and colour change of the coupon surface were utilized. For thin corrosion layers formed micro Raman and FTIR did not provide suitable results, and GIXRD have been used. Although limited number of conditions were used for the simulations, synergistic effect was observed for lead under specific conditions. Synergistic effect do occur on lead when exposed to NOX and acetic acid fumes of relatively low concentrations (18 μg·m-3 and 500 ppb respectively). In addition, there is grouping of colourimetric data collected according to test regimes-phase composition of corrosion product respectively. This information albeit preliminary suggests that colourimetric spectroscopy may be suitable as fast and easy corrosion monitoring

Microstructural characterization of dental zinc phosphate cements using combined small angle neutron scattering and microfocus X-ray computed tomography

Objective To characterize the microstructure of two zinc phosphate cement formulations in order to investigate the role of liquid/solid ratio and composition of powder component, on the developed porosity and, consequently, on compressive strength. Methods X-ray powder diffraction with the Rietveld method was used to study the phase composition of zinc oxide powder and cements. Powder component and cement microstructure were investigated with scanning electron microscopy. Small angle neutron scattering (SANS) and microfocus X-ray computed tomography (XmCT) were together employed to characterize porosity and microstructure of dental cements. Compressive strength tests were performed to evaluate their mechanical performance. Results The beneficial effects obtained by the addition of Al, Mg and B to modulate powder reactivity were mitigated by the crystallization of a Zn aluminate phase not involved in the cement setting reaction. Both cements showed spherical pores with a bimodal distribution at the micro/nano-scale. Pores, containing a low density gel-like phase, developed through segregation of liquid during setting. Increasing liquid/solid ratio from 0.378 to 0.571, increased both SANS and XmCT-derived specific surface area (by 56% and 22%, respectively), porosity (XmCT-derived porosity increased from 3.8% to 5.2%), the relative fraction of large pores ≥50 μm, decreased compressive strength from 50 ± 3 MPa to 39 ± 3 MPa, and favored microstructural and compositional inhomogeneities. Significance Explain aspects of powder design affecting the setting reaction and, in turn, cement performance, to help in optimizing cement formulation. The mechanism behind development of porosity and specific surface area explains mechanical performance, and processes such as erosion and fluoride release/uptake

Core flow experiment protocol

This letter report describes the current status of the core flow through apparatus and describes the protocol and test matrix to be followed during the initial experimental stage of radionuclide transport studies in the Integrated Testing task

Measurement of event shapes in deep inelastic scattering at HERA

Inclusive event-shape variables have been measured in the current region of the Breit frame for neutral current deep inelastic ep scattering using an integrated luminosity of 45.0 pb^-1 collected with the ZEUS detector at HERA. The variables studied included thrust, jet broadening and invariant jet mass. The kinematic range covered was 10 < Q^2 < 20,480 GeV^2 and 6.10^-4 < x < 0.6, where Q^2 is the virtuality of the exchanged boson and x is the Bjorken variable. The Q dependence of the shape variables has been used in conjunction with NLO perturbative calculations and the Dokshitzer-Webber non-perturbative corrections (`power corrections') to investigate the validity of this approach.Comment: 7+25 pages, 6 figure

Microstructural characterization of dental zinc phosphate cements using combined small angle neutron scattering and microfocus X-ray computed tomography.

Abstract Objective To characterize the microstructure of two zinc phosphate cement formulations in order to investigate the role of liquid/solid ratio and composition of powder component, on the developed porosity and, consequently, on compressive strength. Methods X-ray powder diffraction with the Rietveld method was used to study the phase composition of zinc oxide powder and cements. Powder component and cement microstructure were investigated with scanning electron microscopy. Small angle neutron scattering (SANS) and microfocus X-ray computed tomography (XmCT) were together employed to characterize porosity and microstructure of dental cements. Compressive strength tests were performed to evaluate their mechanical performance. Results The beneficial effects obtained by the addition of Al, Mg and B to modulate powder reactivity were mitigated by the crystallization of a Zn aluminate phase not involved in the cement setting reaction. Both cements showed spherical pores with a bimodal distribution at the micro/nano-scale. Pores, containing a low density gel-like phase, developed through segregation of liquid during setting. Increasing liquid/solid ratio from 0.378 to 0.571, increased both SANS and XmCT-derived specific surface area (by 56% and 22%, respectively), porosity (XmCT-derived porosity increased from 3.8% to 5.2%), the relative fraction of large pores ≥50 μm, decreased compressive strength from 50 ± 3 MPa to 39 ± 3 MPa, and favored microstructural and compositional inhomogeneities. Significance Explain aspects of powder design affecting the setting reaction and, in turn, cement performance, to help in optimizing cement formulation. The mechanism behind development of porosity and specific surface area explains mechanical performance, and processes such as erosion and fluoride release/uptake

Angular and Current-Target Correlations in Deep Inelastic Scattering at HERA

Correlations between charged particles in deep inelastic ep scattering have been studied in the Breit frame with the ZEUS detector at HERA using an integrated luminosity of 6.4 pb-1. Short-range correlations are analysed in terms of the angular separation between current-region particles within a cone centred around the virtual photon axis. Long-range correlations between the current and target regions have also been measured. The data support predictions for the scaling behaviour of the angular correlations at high Q2 and for anti-correlations between the current and target regions over a large range in Q2 and in the Bjorken scaling variable x. Analytic QCD calculations and Monte Carlo models correctly describe the trends of the data at high Q2, but show quantitative discrepancies. The data show differences between the correlations in deep inelastic scattering and e+e- annihilation.Comment: 26 pages including 10 figures (submitted to Eur. J. Phys. C

Inclusive jet cross sections in the Breit frame in neutral current deep inelastic scattering at HERA and determination of αs\alpha_{s}

Inclusive jet differential cross sections have been measured in neutral current deep inelastic e+p scattering for boson virtualities Q**2>125 GeV**2. The data were taken using the ZEUS detector at HERA and correspond to an integrated luminosity of 38.6 pb-1. Jets were identified in the Breit frame using the longitudinally invariant K_T cluster algorithm. Measurements of differential inclusive jet cross sections are presented as functions of jet transverse energy (E_T,jet), jet pseudorapidity and Q**2, for jets with E_T,jet>8 GeV. Next-to-leading-order QCD calculations agree well with the measurements both at high Q**2 and high E_T,jet. The value of alpha_s(M_Z), determined from an analysis of dsigma/dQ**2 for Q**2>500 GeV**2, is alpha_s(M_Z) = 0.1212 +/- 0.0017 (stat.) +0.0023 / -0.0031 (syst.) +0.0028 / -0.0027 (th.)

Searches for excited fermions in ep collisions at HERA

Searches in ep collisions for heavy excited fermions have been performed with the ZEUS detector at HERA. Excited states of electrons and quarks have been searched for in e^+p collisions at a centre-of-mass energy of 300 GeV using an integrated luminosity of 47.7 pb^-1. Excited electrons have been sought via the decays e*->egamma, e*->eZ and e*->nuW. Excited quarks have been sought via the decays q*->qgamma and q*->qW. A search for excited neutrinos decaying via nu*->nugamma, nu*->nuZ and nu*->eW is presented using e^-p collisions at 318 GeV centre-of-mass energy, corresponding to an integrated luminosity of 16.7 pb^-1. No evidence for any excited fermion is found, and limits on the characteristic couplings are derived for masses below 250 GeV