X-ray photoelectron spectroscopic study of impregnated La0.4Sr0.6Ti0.8Mn0.2O3±d anode material for high temperature-operating solid oxide fuel cell

In this study, the chemical states of a powder type and an impregnated type of the La0.4Sr0.6Ti0.8Mn0.2O3±d (LSTM) oxide system were investigated along with its electrical conductivities in order to apply these materials as alternative anode materials for high temperature-operating Solid Oxide Fuel Cells (HT-SOFCs). The Ni/8YSZ samples with LSTM impregnated into the pores created by partially removing nickel, Ni/8YSZ (Ni (R)/8YSZ), showed much higher electrical conductivity values than those of unimpregnated Ni/8YSZ (Ni (E)/8YSZ) samples under dry H2 fuel condition. Reduction of Mn4+ to Mn3+ was observed when LSTM was reduced. Additional reduction properties of Mn2+ from Mn3+ and satellite peaks were found when impregnated LSTM was coated onto a Ni/8YSZ substrate. The reduction of the charge state of Ti contained in LSTM showed the same behavior as the reduction property of Mn. However, a satellite peak identified as metal Ti was only observed when impregnated LSTM was coated on a selectively Ni-removed Ni/8YSZ (Ni (R)/8YSZ) substrate

The challenge to professionals of using social media: teachers in England negotiating personal-professional identities

Social media are a group of technologies such as Twitter, Facebook and LinkedIn which offer people chances to interact with one another in new ways. Teachers, like other members of society, do not all use social media. Some avoid, some experiment with and others embrace social media enthusiastically. As a means of communication available to everyone in modern society, social media is challenging teachers, as other professionals in society, to decide whether to engage with these tools and, if so, on what basis – as an individual (personally), or as a teacher (professionally). Although teachers are guided by schools and codes of practice, teachers as individuals are left to decide whether and how to explore social media for either their own or their students' learning. This paper analyses evidence from interviews with 12 teachers from England about their use of social media as to the challenges they experience in relation to using the media as professional teachers.. Teachers are in society’s spotlight in terms of examples of inappropriate use of social media but also under peer pressure to connect. This paper explores their agency in responding. The paper focuses on how teachers deal with tensions between their personal and professional use of social media. These tensions are not always perceived as negative and some teachers' accounts revealed a unity in their identities when using social media. The paper reflects on the implications of such teachers' identities in relation to the future of social media use in education

Heavy quarkonium: progress, puzzles, and opportunities

A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the $B$-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b}, and b\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K. Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D. Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A. Petrov, P. Robbe, A. Vair

CMS physics technical design report : Addendum on high density QCD with heavy ions

Peer reviewe

J/psi production as a function of charged-particle pseudorapidity density in p-Pb collisions at root s(NN)=5.02 TeV

We report measurements of the inclusive J/ψ yield and average transverse momentum as a function of charged-particle pseudorapidity density dNch/dη in p–Pb collisions at sNN=5.02TeV with ALICE at the LHC. The observables are normalised to their corresponding averages in non-single diffractive events. An increase of the normalised J/ψ yield with normalised dNch/dη, measured at mid-rapidity, is observed at mid-rapidity and backward rapidity. At forward rapidity, a saturation of the relative yield is observed for high charged-particle multiplicities. The normalised average transverse momentum at forward and backward rapidities increases with multiplicity at low multiplicities and saturates beyond moderate multiplicities. In addition, the forward-to-backward nuclear modification factor ratio is also reported, showing an increasing suppression of J/ψ production at forward rapidity with respect to backward rapidity for increasing charged-particle multiplicity

Effects of Support on the Performance of NiO-Based Oxygen Carriers Effets du support sur les performances de matériaux transporteurs d’oxygène à base d’oxyde de nickel

The performance of an oxygen carrier for Chemical Looping Combustion varies with the support material used. NiO oxygen carriers were prepared using 60 or 70 wt% NiO and different raw support materials (γ-Al2O3, pseudoboehmite, α-Al2O3, γ-Al2O3 mixed with MgO, hydrotalcite, MgAl2O4, and γ-Al2O3 with added graphite) by the mechanical mixing method. Reactivity tests were conducted using a thermogravimetric analyzer (TGA) at 950˚C. The oxygen carriers prepared using γ-Al2O3, γ-Al2O3 mixed with a small amount of MgO, hydrotalcite, and MgAl2O4 showed high oxygen transfer capacity, high oxygen utilization, and a high oxygen transfer rate. Graphite addition to γ-Al2O3 did not increase the surface area or reactivity. The use of pseudoboehmite as a support led to a significant decrease in oxygen transfer capacity and severe agglomeration of the oxygen carriers during the redox reaction. The increase in MgO content in the raw support materials decreased the reduction reactivity. The oxygen carriers prepared with α-Al2O3 showed less oxygen transfer capacity than the other oxygen carriers. The differences in the reactivity according to the support type were explained by the relative strength of NiO-support interaction obtained from the temperature-programmed reduction analysis. The reactivity test results in this work indicate that γ-Al2O3 and hydrotalcite could be desirable raw support materials to prepare highly reactive NiO oxygen carriers with high NiO content. <br> Les performances des materiaux transporteurs d’oxygene varient en fonction du support utilise dans le procede de combustion en boucle chimique. Differents materiaux a base d’oxyde de Nickel ont ete synthetises avec des concentrations elevees en NiO, comprises entre 60 et 70 %, sur differents supports (γ-Al2O3, pseudobohemite, α-Al2O3, γ-Al2O3 melangee avec MgO, hydrotalcite, MgAl2O4 et γ-Al2O3 additivees avec du graphite) par melange mecanique. Des tests de reactivite ont ete conduits dans une thermobalance (ATG) a 950˚C. Les materiaux supportes avec γ-Al2O3, γ-Al2O3 melangee avec MgO, l’hydrotalcite et MgAl2O4 ont une capacite de transfert d’oxygene elevee et une reactivite elevee. L’addition de graphite dans l’alumine γ n’ameliore ni la surface specifique ni la reactivite. Avec la pseudo-bohemite, on observe une decroissance de la capacite de transfert d’oxygene et l’agglomeration du materiau pendant la phase de reduction. L’ajout de MgO conduit a une baisse de la reactivite en reduction. Avec l’alumine α, la capacite de transfert est reduite. Les differences de reactivite peuvent etre expliquees par les interactions entre NiO et le support, a partir d’analyses en reduction par temperature programmee. Les tests de reactivite conduits dans cette etude suggerent que les supports a base de γ-Al2O3 et d’hydrotalcite sont les plus appropries pour preparer les transporteurs d’oxygene contenant de l’oxyde de Nickel a haute concentration pour la combustion en boucle chimique