2-(1,4-Dioxo-1,4-dihydro-2-naphthyl)-2-methylpropanoic acid

The sterically crowded title compound, C₁₄H₁₂O₄, crystallizes as centrosymmetric hydrogen-bonded dimers involving the carboxyl groups. The naphthoquinone ring system is folded by 11.5 (1)° about a vector joining the 1,4-C atoms, and the quinone O atoms are displaced from the ring plane, presumably because of steric interactions with the bulky substituent

Tobermorite ion-exchanger from paper recycling ash and waste glass

Å tobermorite (Ca5(Si)6O16(OH)2.4H2O) and its Al-substituted counterpart are layer-lattice cation-exchangers that are of interest with respect to their applications in nuclear and hazardous wastewater treatment [1-3]. In 2015, the European Declaration on Paper Recycling reported that 71.5% of all paper consumed in Europe was recycled, corresponding to 1.2 million tonnes more than their 70% target [4]. Waste paper recycling ash (PRA) arising from this activity contains reactive calcium aluminosilicate phases that can be used for the hydrothermal synthesis of tobermorite when stoichiometrically adjusted with additional silicate-bearing reagents [1]. Waste soda-lime-silica container glass (SCG) has also been used as a partial feedstock for the preparation tobermorite in alkaline media [2]. This research tested the feasibility of a one-step synthesis of tobermorite from a combination of PRA and SCG under alkaline hydrothermal conditions at 100 °C. Reaction products were analysed by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). This study also evaluated the Cs+ cation-exchange capacity (CEC), selective Cs+ distribution coefficients (Kd, from Na+ and Ca2+ background solutions) and the uptake kinetics of Cd2+ and Pb2+ by the waste-derived tobermorite produc

Waste-derived inosilicate carrier for antimicrobial Zn2+ and Ag+ ions

Recent research by the authors has demonstrated that the inosilicate, lithium metasilicate (Li2SiO3), can be prepared by hydrothermal synthesis from waste green container glass (GCG) [1,2]. This study investigated the potential of this material to be ion-exchanged with antimicrobial Zn2+ or Ag+ ions for use as a filler in polymer composites. Antimicrobial polymer composites are an advantage in applications where the communication of pathogenic bacteria poses a problem, such as hospitals, abattoirs and food-processing factories. The naturally-occurring biodegradable mucopolysaccharide derivative, chitosan, was used as a model polymer in this study. The lithium metasilicate product was synthesised from GCG in LiOH(aq) and ion-exchanged with either Zn2+ or Ag+ ions via batch sorption. The in vitro antibacterial properties of solvent-cast metasilicate-chitosan composite membranes were then evaluated by zone of inhibition against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus

Seasonally variant stable isotope baseline characterisation of Malawi's Shire River Basin to support integrated water resources management

Integrated Water Resources Management (IWRM) is vital to the future of Malawi and motivates this study's provision of the first stable isotope baseline characterization of the Shire River Basin (SRB). The SRB drains much of Southern Malawi and receives the sole outflow of Lake Malawi whose catchment extends over much of Central and Northern Malawi (and Tanzania and Mozambique). Stable isotope (283) and hydrochemical (150) samples were collected in 2017-2018 and analysed at Malawi's recently commissioned National Isotopes Laboratory. Distinct surface water dry-season isotope enrichment and wet-season depletion are shown with minor retention of enriched signatures ascribed to Lake Malawi influences. Isotopic signatures corroborate that wet-season river flows mostly arise from local precipitation, with dry-season flows supported by increased groundwater contributions. Groundwater signatures follow a local meteoric water line of limited spread suggesting recharge by local precipitation predominantly during the peak months of the wet-season. Relatively few dry-season groundwater samples displayed evaporative enrichment, although isotopic seasonality was more pronounced in the lowlands compared to uplands ascribed to amplified climatic effects. These signatures serve as isotopic diagnostic tools that valuably informed a basin conceptual model build and, going forward, may inform key identified Malawian IWRM concerns. The isotopic baseline establishes a benchmark against which future influences from land use, climate change and water mixing often inherent to IWRM schemes may be forensically assessed. It thereby enables both source-water protection and achievement of Sustainable Development Goal 6

Quantum decision making by social agents

The influence of additional information on the decision making of agents, who are interacting members of a society, is analyzed within the mathematical framework based on the use of quantum probabilities. The introduction of social interactions, which influence the decisions of individual agents, leads to a generalization of the quantum decision theory developed earlier by the authors for separate individuals. The generalized approach is free of the standard paradoxes of classical decision theory. This approach also explains the error-attenuation effects observed for the paradoxes occurring when decision makers, who are members of a society, consult with each other, increasing in this way the available mutual information. A precise correspondence between quantum decision theory and classical utility theory is formulated via the introduction of an intermediate probabilistic version of utility theory of a novel form, which obeys the requirement that zero-utility prospects should have zero probability weights.Comment: This paper has been withdrawn by the authors because a much extended and improved version has been submitted as arXiv:1510.02686 under the new title "Role of information in decision making of social agents

Photodoping through local charge carrier accumulation in alloyed hybrid perovskites for highly efficient luminescence

© 2019, The Author(s), under exclusive licence to Springer Nature Limited. Metal halide perovskites have emerged as exceptional semiconductors for optoelectronic applications. Substitution of the monovalent cations has advanced luminescence yields and device efficiencies. Here, we control the cation alloying to enhance optoelectronic performance through alteration of the charge carrier dynamics in mixed-halide perovskites. In contrast to single-halide perovskites, we find high luminescence yields for photoexcited carrier densities far below solar illumination conditions. Using time-resolved spectroscopy we show that the charge carrier recombination regime changes from second to first order within the first tens of nanoseconds after excitation. Supported by microscale mapping of the optical bandgap, electrically gated transport measurements and first-principles calculations, we demonstrate that spatially varying energetic disorder in the electronic states causes local charge accumulation, creating p- and n-type photodoped regions, which unearths a strategy for efficient light emission at low charge-injection in solar cells and light-emitting diodes.S.F. acknowledges funding from the Studienstiftung des deutschen Volkes and EPSRC, as well as support from the Winton Programme for the Physics of Sustainability. S.M. acknowledges funding from an EPSRC studentship. M.A.-J. thanks Nava Technology Limited, Cambridge Materials Limited and EPSRC (grant number: EP/M005143/1) for their funding and technical support. S.P.S. acknowledges funding from the Royal Society Newton Fellowship and EPSRC through a program grant (EP/M005143/1). T.A.S.D. acknowledges the National University of Ireland (NUI) for a Travelling Studentship and the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (HYPERION, grant agreement number 756962). K.F. acknowledges funding from a George and Lilian Schiff Foundation Studentship, an EPSRC studentship and a scholarship from the Winton Programme for the Physics of Sustainability. E.R. acknowledges funding from an ERC starting grant (no. 804523). R.H.F. acknowledges support from the Simons Foundation (grant 601946). Research work in Mons was supported by the Fonds de la Recherche Scientifique de Belgique - Fund for Scientific Research (F.R.S.-FNRS) and the EU Marie-Curie IEF project ‘DAEMON’. Computational resources have been provided by the Consortium des Équipements de Calcul Intensif (CÉCI). D.B. is an FNRS Research Director. S.D.S. acknowledges the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (HYPERION, grant agreement number 756962), the Royal Society and Tata Group (UF150033). F.D. acknowledges funding from the Winton Programme for the Physics of Sustainability