59-Co and 75-As NMR Investigation of Electron-Doped High Tc Superconductor BaFe(1.8)Co(0.2)As(2) (Tc = 22K)

We report an NMR investigation of the superconductivity in BaFe(2)As(2) induced by Co doping (Tc=22K). We demonstrate that Co atoms form an alloy with Fe atoms and donate carriers without creating localized moments. Our finding strongly suggests that the underlying physics of iron-pnictide superconductors is quite different from the widely accepted physical picture of high Tc cuprates as doped Mott insulators. We also show a crossover of electronic properties into a low temperature pseudo-gap phase with a pseudo-gap Delta 560K, where chi(spin) constant and resisitivty T. The NMR Knight shift below Tc decreases for both along the c-axis and ab-plane, and is consistent with the singlet pairing scenario.Comment: Accepted for publication in J. Phys. Soc. Jpn. (4 pages

Achieving urban flood resilience in an uncertain future

Preliminary results of the UK Urban Flood Resilience research consortium are presented and discussed, with the work being conducted against a background of future uncertainties with respect to changing climate and increasing urbanization. Adopting a whole systems approach, key themes include developing adaptive approaches for flexible engineering design of coupled grey and blue-green flood management assets; exploiting the resource potential of urban stormwater through rainwater harvesting, urban metabolism modelling and interoperability; and investigating the interactions between planners, developers, engineers and communities at multiple scales in managing flood risk. The work is producing new modelling tools and an extensive evidence base to support the case for multifunctional infrastructure that delivers multiple, environmental, societal and economic benefits, while enhancing urban flood resilience by bringing stormwater management and green infrastructure together.</jats:p

A Unified Description of Cuprate and Iron Arsenide Superconductors

We propose a unified description of cuprate and iron-based superconductivity. Consistency with magnetic structure inferred from neutron scattering implies significant constraints on the symmetry of the pairing gap for the iron-based superconductors. We find that this unification requires the orbital pairing formfactors for the iron arsenides to differ fundamentally from those for cuprates at the microscopic level.Comment: 12 pages, 10 figures, 2 table

The blue-green path to urban flood resilience

Abstract Achieving urban flood resilience at local, regional and national levels requires a transformative change in planning, design and implementation of urban water systems. Flood risk, wastewater and stormwater management should be re-envisaged and transformed to: ensure satisfactory service delivery under flood, normal and drought conditions, and enhance and extend the useful lives of ageing grey assets by supplementing them with multi-functional Blue-Green infrastructure. The aim of the multidisciplinary Urban Flood Resilience (UFR) research project, which launched in 2016 and comprises academics from nine UK institutions, is to investigate how transformative change may be possible through a whole systems approach. UFR research outputs to date are summarised under three themes. Theme 1 investigates how Blue-Green and Grey (BG + G) systems can be co-optimised to offer maximum flood risk reduction, continuous service delivery and multiple co-benefits. Theme 2 investigates the resource capacity of urban stormwater and evaluates the potential for interoperability. Theme 3 focuses on the interfaces between planners, developers, engineers and beneficiary communities and investigates citizens’ interactions with BG + G infrastructure. Focussing on retrofit and new build case studies, UFR research demonstrates how urban flood resilience may be achieved through changes in planning practice and policy to enable widespread uptake of BG + G infrastructure.EPSR

EuFe2_2As2_2 under high pressure: an antiferromagnetic bulk superconductor

We report the ac magnetic susceptibility $\chi_{ac}$ and resistivity $\rho$ measurements of EuFe$_2$As$_2$ under high pressure $P$. By observing nearly 100% superconducting shielding and zero resistivity at $P$ = 28 kbar, we establish that $P$-induced superconductivity occurs at $T_c \sim$~30 K in EuFe$_2$As$_2$. $\rho$ shows an anomalous nearly linear temperature dependence from room temperature down to $T_c$ at the same $P$. $\chi_{ac}$ indicates that an antiferromagnetic order of Eu$^{2+}$ moments with $T_N \sim$~20 K persists in the superconducting phase. The temperature dependence of the upper critical field is also determined.Comment: To appear in J. Phys. Soc. Jpn., Vol. 78 No.