Shock-wave equation of state of rhyolite

We have obtained new shock-wave equation of state (EOS) and release adiabat data for rhyolite. These data are combined with those of Swegle (1989, 1990) to give an experimental Hugoniot which is described by U_s = 2.53(±0.08) + 3.393(±0.37)u_p for u_p < 0.48 km s^(−1), U_s = 3.85(±0.05) + 0.65(±0.03)up for 0.48 ≤ u_p < 2.29 km s^(−1), U_s = 1.52(±0.08) + 1.67(±0.02)u_p for 2.29 ≤ u_p < 4.37 km s^(−1), and U_s = 3.40(±034) + 1.24(±0.06)u_p for u_p ≥ 4.37 km s^(−1), with ρ_0 = 2.357 ± 0.052 Mg m^(−3). We suggest that the Hugoniot data give evidence of three distinct phases—both low- and high-pressure solid phases and, possibly, a dense molten phase. EOS parameters for these phases are ρ_0 = 2.494 ± 0.002 Mg m^(−3), K_(S0) = 37 ± 2 GPa, K′ = 6.27 ± 0.25, and γ = 1.0(V/V_0) for the low-pressure solid phase; ρ_0 = 3.834 ± 0.080 Mg m^(−3), K_(S0) = 128 ± 20 GPa, K′ = 3.7 ± 1.4, and γ = 1.5 ± 0.5 for the solid high-pressure phase; and ρ_0 = 3.71 ± 0.10 Mg m^(−3), K_(S0) = 127 ± 25 GPa, K′ = 2.1 ± 1.0, and γ = 1.5 ± 1.0 for the dense liquid. Transition regions of the Hugoniot cover the ranges of 9–34 GPa for the low-pressure—high-pressure solid transition and 90–120 GPa for the high-pressure solid—liquid transition. Release paths from high-pressure states, calculated from the EOS parameters, suggest that the material remains in the high-pressure solid phase upon release. Release paths from both the high-pressure solid and liquid fall above the Hugoniot until the Hugoniot enters the low-pressure—high-pressure mixed phase region, when the release paths then cross the Hugoniot and fall below it, ending at significantly higher zero-pressure densities than that of the low-pressure phase. The low-pressure release paths fall very close to the Hugoniot. Estimates of residual heat deposition, based on shock-release path hysteresis, range from 20 to 60 per cent of the shock Hugoniot energy

Spin chirality fluctuation in two-dimensional ferromagnets with perpendicular anisotropy

Non-coplanar spin textures with scalar spin chirality can generate effective magnetic field that deflects the motion of charge carriers, resulting in topological Hall effect (THE), a powerful probe of the ground state and low-energy excitations of correlated systems. However, spin chirality fluctuation in two-dimensional ferromagnets with perpendicular anisotropy has not been considered in prior studies. Herein, we report direct evidence of universal spin chirality fluctuation by probing the THE above the transition temperatures in two different ferromagnetic ultra-thin films, SrRuO$_3$ and V doped Sb$_2$Te$_3$. The temperature, magnetic field, thickness, and carrier type dependences of the THE signal, along with our Monte-Carlo simulations, unambiguously demonstrate that the spin chirality fluctuation is a universal phenomenon in two-dimensional Ising ferromagnets. Our discovery opens a new paradigm of exploring the spin chirality with topological Hall transport in two-dimensional magnets and beyondComment: accepted by nature material

Compact Optimization Learning for AC Optimal Power Flow

This paper reconsiders end-to-end learning approaches to the Optimal Power Flow (OPF). Existing methods, which learn the input/output mapping of the OPF, suffer from scalability issues due to the high dimensionality of the output space. This paper first shows that the space of optimal solutions can be significantly compressed using principal component analysis (PCA). It then proposes Compact Learning, a new method that learns in a subspace of the principal components before translating the vectors into the original output space. This compression reduces the number of trainable parameters substantially, improving scalability and effectiveness. Compact Learning is evaluated on a variety of test cases from the PGLib with up to 30,000 buses. The paper also shows that the output of Compact Learning can be used to warm-start an exact AC solver to restore feasibility, while bringing significant speed-ups.Comment: Submitted to IEEE Transactions on Power System

Sustainable intensification of aquaculture value chains between Asia and Europe: A framework for understanding impacts and challenges

Sustainable intensification (SI) is defined and interpreted in terms of a framework to support production of farmed aquatic animals in Asia and their trade with Europe. A novel holistic perspective to value chain analysis, informed by a range of sustainability tools, is used to explain the dynamic in the trade that is having significant impacts on livelihoods in both regions. The origins of SI in agriculture are first described and their congruence with aquaculture clarified. Asian aquaculture systems, based on their emergent properties, are then located within a SI framework considering possible boundaries (enterprise, zone or whole value chain). The implications of conventional intensification, and alternatives are explored with reference to specific examples and impacts on the local and global environment, human and aquatic animal health and welfare. The challenges to sustainability of such value chains and implications for their governance, food culture and consumer habits are considered. Local consumption of seafood in Asia is found to be a major driver of growth and alternative markets for exports regionally and in Low and Medium income countries (LMIC) are likely to impact on employment and power in the value chain between Europe and Asia. The benefits of viewing farmed seafood as part of broader food landscapes are identified in the analysis, as is a shift in the focus from volume to value in terms of goal setting. More holistic perspectives of sustainability also emerge as necessary to describe and interpret global value chains rather than limited reductionist, production- orientated views. A diversity of trends in the development of farmed seafood is identified in contrast to any simplistic move to intensification, likely informed by economic, environmental and social factors in producer and consumer countries.  Statement of relevance  Global imbalances in production and consumption of farmed seafood are stimulating trade between Asia and Europe. The dynamic of global value chains around this emergent trade and their alignment with broader sustainability criteria, as applied to sustainable intensification of food production, are highly relevant to global food security

High-throughput first-principles calculations as a powerful guiding tool for materials engineering: Case study of the AB2X4 (A = Be, Mg, Ca, Sr, ba; B = Al, Ga, in; X = O, S) spinel compounds

Modern methods of theoretical and experimental materials engineering can be greatly facilitated by reliably established guiding trends that set directions for a smart search for new materials with enhanced performance. Those trends can be derived from a thorough analysis of large arrays of the experimental data, obtained both experimentally and theoretically. In the present paper, the structural, elastic, and electronic properties of 30 spinel compounds AB 2 X 4 (A = Be, Mg, Ca, Sr, Ba; B = Al, Ga, In; X = O, S) were investigated using the CRYSTAL14 program. For the first time the lattice constants, bulk moduli, band gaps and density of states for these 30 spinels were systematically calculated and analyzed. Influence of the cation and anion variation on the above-mentioned properties was highlighted. Several relations between lattice constants, bulk modulus and ionic radii, electronegativities of constituting ions were found. Several linear equations are proposed, which provide a convenient way to predict the lattice constants and bulk moduli of isostructural spinels. © 201

Influence of sulfur oxidation state and substituents on sulfur-bridged luminescent copper(I) complexes showing thermally activated delayed fluorescence

C.M.B. thanks Dr. Maria B. Ezhova for helpful discussions regarding NMR spectra, and Dr. Saeid Kamal for assistance with the TCSPC data. C.M.B. and M.O.W. acknowledge the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Peter Wall Institute for Advanced Studies for financial support and the Laboratory for Advanced Spectroscopy for Imaging Research (LASIR) for facilities access. Z.X. thanks Compute Canada for computing resources for DFT calculations. C.L. thanks the Prof. & Mrs. Purdie Bequests Scholarship and AstraZeneca PhD Studentship. E.Z.-C. and I.D.W.S thank EPSRC (grants EP/R035164/1 and EP/L017008/1) for financial support.Copper(I) complexes are seen as more sustainable alternatives to those containing metal ions such as iridium and platinum for emitting devices. Copper(I) complexes have the ability to radiatively decay via a thermally activated delayed fluorescence (TADF) pathway, leading to higher photoluminescent quantum yields. In this work we discuss six new heteroleptic Cu(I) complexes of the diphosphine–diimine motif. The diphosphine ligands employed are (oxydi- 2,1-phenylene)bis(diphenylphosphine) (DPEPhos) and the diimine fragments are sulfur- bridged dipyridyl ligands (DPS) which are functionalized at the 6,6′-positions of the pyridyl rings (R = H, Me, Ph), and have varying oxidation states at the bridging sulfur atom (S, SO2). The proton ( Cu-DPS, Cu-DPSO2 ) and phenyl ( Cu-Ph-DPS, Cu-Ph-DPSO2 ) substituted species are found to form monometallic complexes, while those with methyl substitution ( Cu-Me-DPS, Cu-Me-DPSO2 ) are found to have a “Goldilocks” degree of steric bulk leading to bimetallic species. All six Cu(I) complexes show emission in the solid state, with the photophysical properties characterized by low temperature steady-state and time-resolved spectroscopies and variable temperature time-correlated single photon counting (TCSPC). Cu- DPS , Cu-DPSO2 , Cu-Me-DPS , Cu-Me-DPSO2 and Cu-Ph-DPSO2 were shown to emit via a TADF mechanism, while Cu-Ph-DPS showed photoluminescence properties consistent with triplet ligand-centered (3LC) emission.PostprintPeer reviewe

Global Seafood Trade: Insights in Sustainability Messaging and Claims of the Major Producing and Consuming Regions

Seafood supply chains are complex, not least in the diverse origins of capture fisheries and through aquaculture production being increasingly shared across nations. The business-to-business (B2B) seafood trade is supported by seafood shows that facilitate networking and act as fora for signaling of perceptions and values. In the Global North, sustainability related certifications and messaging have emerged as an important driver to channel the demands of consumers, institutions, and lead firms. This study investigates which logos, certifications, and claims were presented at the exhibitor booths within five seafood trade shows in China, Europe, and USA. The results indicate a difference in the way seafood is advertised. Messaging at the Chinese shows had less of an emphasis on sustainability compared to that in Europe and the USA, but placed a greater emphasis on food safety and quality than on environmental concerns. These findings suggest cultural differences in the way seafood production and consumption is communicated through B2B messaging. Traders often act as choice editors for final consumers. Therefore, it is essential to convey production processes and sustainability issues between traders and the market. An understanding of culture, messaging strategies, and interpretation could support better communication of product characteristics such as sustainability between producers, traders, and consumers

Spiro-based thermally activated delayed fluorescence emitters with reduced nonradiative decay for high-quantum-efficiency, low-roll-off, organic light-emitting diodes

E.Z.-C. thanks the Leverhulme Trust (No. RPG-2016-047) and the University of St Andrews for support. The authors are grateful to the EPSRC for financial support (grants EP/ P007805/1, EP/P010482/1, EP/L017008/1, EP/J01771X, and EP/J00916). M.M. thanks the Innovation Programme H2020-MSCA-IF-2014-659237 for financial support. W.L. thanks the China Scholarship Council (grant number 201708060003). V.L. thanks the F.R.S.-FNRS for his Research Associate position. Computational resources have been provided by the Consortium des É quipements de Calcul Intensif (CÉ CI), funded by the Fonds de la Recherche Scientifiques de Belgique (F.R.S.FNRS) under Grant No. 2.5020.11, GEQ U.G006.15, 1610468, and RW/GEQ. (2016). D.B. is an FNRS Research Director.Herein, we report the use of spiro-configured fluorene-xanthene scaffolds as a novel, promising, and effective strategy in thermally activated delayed fluorescence (TADF) emitter design to attain high photoluminescence quantum yields (ΦPL), short delayed luminescence lifetime, high external quantum efficiency (EQE), and minimum efficiency roll-off characteristics in organic light-emitting diodes (OLEDs). The optoelectronic and electroluminescence properties of SFX (spiro-(fluorene-9,9′-xanthene))-based emitters (SFX-PO-DPA, SFX-PO-DPA-Me, and SFX-PO-DPA-OMe) were investigated both theoretically and experimentally. All three emitters exhibited sky blue to green emission enabled by a Herzberg–Teller mechanism in the excited state. They possess short excited-state delayed lifetimes (<10 μs), high photoluminescence quantum yields (ΦPL ∼ 70%), and small singlet–triplet splitting energies (ΔEST < 0.10 eV) in the doped films in an mCP host matrix. The OLEDs showed some of the highest EQEs using spiro-containing emitters where maximum external quantum efficiencies (EQEmax) of 11 and 16% were obtained for devices using SFX-PO-DPA and SFX-PO-DPA-OMe, respectively. Further, a record EQEmax of 23% for a spiro-based emitter coupled with a low efficiency roll-off (19% at 100 cd m–2) was attained with SFX-PO-DPA-Me.PostprintPostprintPeer reviewe