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1.	Abrahao, FS, et al. (författare) Emergence and algorithmic information dynamics of systems and observers 2022 Ingår i: Philosophical transactions. Series A, Mathematical, physical, and engineering sciences. - : The Royal Society. - 1471-2962. ; 380:2227, s. 20200429- Tidskriftsartikel (refereegranskat)abstract One of the challenges of defining emergence is that one observer’s prior knowledge may cause a phenomenon to present itself as emergent that to another observer appears reducible. By formalizing the act of observing as mutual perturbations between dynamical systems, we demonstrate that the emergence of algorithmic information does depend on the observer’s formal knowledge, while being robust vis-a-vis other subjective factors, particularly: the choice of programming language and method of measurement; errors or distortions during the observation; and the informational cost of processing. This is called observer-dependent emergence (ODE). In addition, we demonstrate that the unbounded and rapid increase of emergent algorithmic information implies asymptotically observer-independent emergence (AOIE). Unlike ODE, AOIE is a type of emergence for which emergent phenomena will be considered emergent no matter what formal theory an observer might bring to bear. We demonstrate the existence of an evolutionary model that displays the diachronic variant of AOIE and a network model that displays the holistic variant of AOIE. Our results show that, restricted to the context of finite discrete deterministic dynamical systems, computable systems and irreducible information content measures, AOIE is the strongest form of emergence that formal theories can attain.This article is part of the theme issue ‘Emergent phenomena in complex physical and socio-technical systems: from cells to societies’.
2.	Agarwal, S., et al. (författare) Fluctuations in Arctic sea-ice extent : Comparing observations and climate models 2018 Ingår i: Philosophical Transactions. Series A. - : Royal Society Publishing. - 1364-503X .- 1471-2962. ; 376:2129 Tidskriftsartikel (refereegranskat)abstract The fluctuation statistics of the observed sea-ice extent during the satellite era are compared with model output from CMIP5 models using a multifractal time series method. The two robust features of the observations are that on annual to biannual time scales the ice extent exhibits white noise structure, and there is a decadal scale trend associated with the decay of the ice cover. It is shown that (i) there is a large inter-model variability in the time scales extracted from the models, (ii) none of the models exhibits the decadal time scales found in the satellite observations, (iii) five of the 21 models examined exhibit the observed white noise structure, and (iv) the multi-model ensemble mean exhibits neither the observed white noise structure nor the observed decadal trend. It is proposed that the observed fluctuation statistics produced by this method serve as an appropriate test bed for modelling studies.
3.	Agrell, Erik, 1965, et al. (författare) Implications of information theory in optical fibre communications 2016 Ingår i: Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. - : The Royal Society. - 1364-503X .- 1471-2962. ; 374:2062 Forskningsöversikt (refereegranskat)abstract Recent decades have witnessed steady improvements in our ability to harness the information-carrying capability of optical fibres. Will this process continue, or will progress eventually stall? Information theory predicts that all channels have a limited capacity depending on the available transmission resources, and thus it is inevitable that the pace of improvements will slow. However, information theory also provides insights into how transmission resources should, in principle, best be exploited, and thus may serve as a guide for where to look for better ways to squeeze more out of a precious resource. This tutorial paper reviews the basic concepts of information theory and their application in fibre-optic communications.
4.	Alfredsson, P. Henrik, et al. (författare) Wind farms in complex terrains : an introduction 2017 Ingår i: Philosophical Transactions. Series A. - : ROYAL SOC. - 1364-503X .- 1471-2962. ; 375:2091 Tidskriftsartikel (refereegranskat)abstract Wind energy is one of the fastest growing sources of sustainable energy production. As more wind turbines are coming into operation, the best locations are already becoming occupied by turbines, and wind-farm developers have to look for new and still available areas-locations that may not be ideal such as complex terrain landscapes. In these locations, turbulence and wind shear are higher, and in general wind conditions are harder to predict. Also, the modelling of the wakes behind the turbines is more complicated, which makes energy-yield estimates more uncertain than under ideal conditions. This theme issue includes 10 research papers devoted to various fluid-mechanics aspects of using wind energy in complex terrains and illustrates recent progress and future developments in this important field. This article is part of the themed issue 'Wind energy in complex terrains'.
5.	Andersson, Lars-Erik, 1942-, et al. (författare) A review of the theory of static and quasi-static frictional contact problems in elasticity 2001 Ingår i: Philosophical Transactions. Series A. - 1364-503X .- 1471-2962. ; 359, s. 2519-2539 Tidskriftsartikel (refereegranskat)
6.	Andersson, Ole, et al. (författare) Geometric phases for mixed states of the Kitaev chain 2016 Ingår i: Philosophical Transactions. Series A. - : The Royal Society. - 1364-503X .- 1471-2962. ; 374:2069 Tidskriftsartikel (refereegranskat)abstract The Berry phase has found applications in building topological order parameters for certain condensed matter systems. The question whether some geometric phase for mixed states can serve the same purpose has been raised, and proposals are on the table. We analyze the intricate behaviour of Uhlmann’s geometric phase in the Kitaev chain at finite temperature, and then argue that it captures quite different physics from that intended. We also analyze the behaviour of a geometric phase introduced in the context of interferometry. For the Kitaev chain, this phase closely mirrors that of the Berry phase, and we argue that it merits further investigation.
7.	Andrighetto, Giulia, et al. (författare) A research agenda for the study of social norm change 2022 Ingår i: Philosophical Transactions. Series A. - : ROYAL SOC. - 1364-503X .- 1471-2962. ; 380:2227 Forskningsöversikt (refereegranskat)abstract Social norms have been investigated across many disciplines for many years, but until recently, studies mainly provided indirect, implicit and correlational support for the role of social norms in driving behaviour. To understand how social norms, and in particular social norm change, can generate a large-scale behavioural change to deal with some of the most pressing challenges of our current societies, such as climate change and vaccine hesitancy, we discuss and review several recent advances in social norm research that enable a more precise underpinning of the role of social norms: how to identify their existence, how to establish their causal effect on behaviour and when norm change may pass tipping points. We advocate future research on social norms to study norm change through a mechanism-based approach that integrates experimental and computational methods in theory-driven, empirically calibrated agent-based models. As such, social norm research may move beyond unequivocal praising of social norms as the missing link between self-interested behaviour and observed cooperation or as the explanation for (the lack of) social tipping. It provides the toolkit to understand explicitly where, when and how social norms can be a solution to solve large-scale problems, but also to recognize their limits.This article is part of the theme issue 'Emergent phenomena in complex physical and socio-technical systems: from cells to societies'.
8.	Argatov, Ivan (författare) Controlling the adhesive pull-off force via the change of contact geometry 2021 Ingår i: Philosophical Transactions. Series A. - : The Royal Society. - 1364-503X .- 1471-2962. ; 379:2203 Tidskriftsartikel (refereegranskat)abstract A first-order asymptotic analysis of the Griffith energy balance in the Johnson-Kendall-Roberts model of adhesive contact under non-symmetric perturbation of the contact geometry is presented. The pull-off force is evaluated in explicit form. A particular case of adhesive contact between a relatively stiff sphere and an elastic half-space is considered under the assumption that the sphere geometry is changed by the application of an arbitrary lateral normal surface loading. The effect of the sphere Poisson's ratio on controlling the adhesive pull-off force is considered.This article is part of a discussion meeting issue 'A cracking approach to inventing new tough materials: fracture stranger than friction'.
9.	Asano, Masanari, et al. (författare) Three-body system metaphor for the two-slit experiment and Escherichia coli lactose-glucose metabolism 2016 Ingår i: Philosophical Transactions. Series A. - : The Royal Society. - 1364-503X .- 1471-2962. ; 374:2068 Tidskriftsartikel (refereegranskat)abstract We compare the contextual probabilistic structures of the seminal two-slit experiment (quantum interference experiment), the system of three interacting bodies and Escherichia coli lactose-glucose metabolism. We show that they have the same non-Kolmogorov probabilistic structure resulting from multi-contextuality. There are plenty of statistical data with non-Kolmogorov features; in particular, the probabilistic behaviour of neither quantum nor biological systems can be described classically. Biological systems (even cells and proteins) are macroscopic systems and one may try to present a more detailed model of interactions in such systems that lead to quantum-like probabilistic behaviour. The system of interactions between three bodies is one of the simplest metaphoric examples for such interactions. By proceeding further in this way (by playing with n-body systems) we shall be able to find metaphoric mechanical models for complex bio-interactions, e.g. signalling between cells, leading to non-Kolmogorov probabilistic data.
10.	Bagarello, F., et al. (författare) A model of adaptive decision-making from representation of information environment by quantum fields 2017 Ingår i: Philosophical Transactions. Series A. - : The Royal Society Publishing. - 1364-503X .- 1471-2962. ; 375:2106 Tidskriftsartikel (refereegranskat)abstract We present the mathematical model of decisionmaking (DM) of agents acting in a complex and uncertain environment (combining huge variety of economical, financial, behavioural and geopolitical factors). To describe interaction of agents with it, we apply the formalism of quantum field theory (QTF). Quantum fields are a purely informational nature. The QFT model can be treated as a far relative of the expected utility theory, where the role of utility is played by adaptivity to an environment (bath). However, this sort of utility- adaptivity cannot be represented simply as a numerical function. The operator representation in Hilbert space is used and adaptivity is described as in quantum dynamics. We are especially interested in stabilization of solutions for sufficiently large time. The outputs of this stabilization process, probabilities for possible choices, are treated in the framework of classical DM. To connect classical and quantum DM, we appeal to Quantum Bayesianism. We demonstrate the quantumlike interference effect in DM, which is exhibited as a violation of the formula of total probability, and hence the classical Bayesian inference scheme. This article is part of the themed issue 'Second quantum revolution: foundational questions'.
11.	Bagheri, Shervin, et al. (författare) Transition delay using control theory 2011 Ingår i: Philosophical Transactions. Series A. - : The Royal Society. - 1364-503X .- 1471-2962. ; 369:1940, s. 1365-1381 Tidskriftsartikel (refereegranskat)abstract This review gives an account of recent research efforts to use feedback control for the delay of laminar-turbulent transition in wall-bounded shear flows. The emphasis is on reducing the growth of small-amplitude disturbances in the boundary layer using numerical simulations and a linear control approach. Starting with the application of classical control theory to two-dimensional perturbations developing in spatially invariant flows, flow control based on control theory has progressed towards more realistic three-dimensional, spatially inhomogeneous flow configurations with localized sensing/actuation. The development of low-dimensional models of the Navier-Stokes equations has played a key role in this progress. Moreover, shortcomings and future challenges, as well as recent experimental advances in this multi-disciplinary field, are discussed.
12.	Bahaj, AbuBakr S. (författare) Marine current energy conversion: the dawn of a new era in electricity production 2013 Ingår i: Philosophical Transactions. Series A. - : The Royal Society. - 1364-503X .- 1471-2962. Tidskriftsartikel (refereegranskat)abstract Marine currents can carry large amounts of energy, largely driven by the tides, which are a consequence of the gravitational effects of the planetary motion of the Earth, the Moon and the Sun. Augmented flow velocities can be found where the underwater topography (bathymetry) in straits between islands and the mainland or in shallows around headlands plays a major role in enhancing the flow velocities, resulting in appreciable kinetic energy. At some of these sites where practical flows are more than 1 m s−1, marine current energy conversion is considered to be economically viable. This study describes the salient issues related to the exploitation of marine currents for electricity production, resource assessment, the conversion technologies and the status of leading projects in the field. This study also summarizes important issues related to site development and some of the approaches currently being undertaken to inform device and array development. This study concludes that, given the highlighted commitments to establish favourable regulatory and incentive regimes as well as the aspiration for energy independence and combating climate change, the progress to multi-megawatt arrays will be much faster than that achieved for wind energy development.
13.	Balmer, R. S., et al. (författare) Unlocking diamond's potential as an electronic material 2008 Ingår i: Philosophical Transactions. Series A. - London : Royal Society of London. - 1364-503X .- 1471-2962. ; 366:1863, s. 251-265 Tidskriftsartikel (refereegranskat)abstract In this paper, we review the suitability of diamond as a semiconductor material for high-performance electronic applications. The current status of the manufacture of synthetic diamond is reviewed and assessed. In particular, we consider the quality of intrinsic material now available and the challenges in making doped structures suitable for practical devices. Two practical applications are considered in detail. First, the development of high-voltage switches capable of switching voltages in excess of 10kV. Second, the development of diamond MESFETs for high-frequency and high-power applications. Here device data are reported showing a current density of more than 30mAmm -1 along with small-signal RF measurements demonstrating gigahertz operation. We conclude by considering the remaining challenges which will need to be overcome if commercially attractive diamond electronic devices are to be manufactured.
14.	Batten, W.M.J., et al. (författare) The accuracy of the actuator disc-RANS approach for predicting the performance and far wake of a horizontal axis tidal stream turbine 2013 Ingår i: Philosophical Transactions. Series A. - : The Royal Society. - 1364-503X .- 1471-2962. Tidskriftsartikel (refereegranskat)abstract The actuator disc-RANS model has been widely used in wind and tidal energy to predict the wake of a horizontal axis turbine. The model is appropriate where large scale effects of the turbine on a flow are of interest, for example, when considering environmental impacts, or arrays of devices. The accuracy of the model for modelling the wake of tidal stream turbines has not been demonstrated, and flow predictions presented in the literature for similar modelled scenarios vary significantly. This paper compares the results of the actuator disc-RANS model, where the turbine forces have been derived using a blade element approach, to experimental data measured in the wake of a scaled turbine. It also compares the results to those of a simpler uniform actuator disc model. The comparisons show that the model is accurate and can predict up to 94\% of the variation in the experimental data measured on the centreline of the wake. The study demonstrates that the actuator-disc RANS model is an accurate approach for modelling a turbine wake, and conservative approach to predict performance and loads. It can therfore applied to similar scenarios with confidence.
15.	Berggren, Karl-Fredrik, et al. (författare) Electrons in one dimension 2010 Ingår i: Philosophical Transactions. Series A. - : The Royal Society. - 1364-503X .- 1471-2962. ; 368, s. 1141-1162 Forskningsöversikt (refereegranskat)abstract In this article, we present a summary of the current status of the study of the transport of electrons confined to one dimension in very low disorder GaAs–AlGaAs heterostructures. By means of suitably located gates and application of a voltage to ‘electrostatically squeeze’ the electronic wave functions, it is possible to produce a controllable size quantization and a transition from two-dimensional transport. If the length of the electron channel is sufficiently short, then transport is ballistic and the quantized subbands each have a conductance equal to the fundamental quantum value 2e2/h, where the factor of 2 arises from the spin degeneracy. This mode of conduction is discussed, and it is shown that a number of many-body effects can be observed. These effects are discussed as in the spin-incoherent regime, which is entered when the separation of the electrons is increased and the exchange energy is less than kT. Finally, results are presented in the regime where the confinement potential is decreased and the electron configuration relaxes to minimize the electron–electron repulsion to move towards a two-dimensional array. It is shown that the ground state is no longer a line determined by the size quantization alone, but becomes two distinct rows arising from minimization of the electrostatic energy and is the precursor of a two-dimensional Wigner lattice.
16.	Bhatnagar, Akshay, et al. (författare) Rate of formation of caustics in heavy particles advected by turbulence 2022 Ingår i: Philosophical Transactions. Series A. - : The Royal Society. - 1364-503X .- 1471-2962. ; 380:2219 Tidskriftsartikel (refereegranskat)abstract The rate of collision and the relative velocities of the colliding particles in turbulent flows are a crucial part of several natural phenomena, e.g. rain formation in warm clouds and planetesimal formation in protoplanetary discs. The particles are often modelled as passive, but heavy and inertial. Within this model, large relative velocities emerge due to formation of singularities (caustics) of the gradient matrix of the velocities of the particles. Using extensive direct numerical simulations of heavy particles in both two (direct and inverse cascade) and three-dimensional turbulent flows, we calculate the rate of formation of caustics, J as a function of the Stokes number (St). The best approximation to our data is J similar to exp(-C/St), in the limit St -> 0 where C is a non-universal constant. This article is part of the theme issue 'Scaling the turbulence edifice (part 2)'.
17.	Black, John H, 1949 (författare) H3+ at the interface between astrochemistry and astroparticle physics 2012 Ingår i: Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. - : The Royal Society. - 1364-503X .- 1471-2962. ; 370:1978, s. 5130-5141 Tidskriftsartikel (refereegranskat)abstract The H3+ molecular ion has been used by Oka and collaborators to trace the rate of ionization by cosmic rays in the interstellar medium. More energetic cosmic rays also produce diffuse γ-radiation. Now that several supernova remnants (SNRs) have been identified as γ-ray sources, it is possible to use spectroscopy of molecular ions to search for enhanced ionization rates that would pinpoint the SNRs as the accelerators of cosmic rays. It is proposed that the warm, dilute molecular gas revealed by Graphic absorption in the central molecular zone of the Galaxy can also be investigated via radio recombination lines of atoms and possibly triatomic hydrogen.
18.	Blomqvist, Björn R. H., et al. (författare) Inferring the dynamics of rising radical right-wing party support using Gaussian processes 2019 Ingår i: Philosophical Transactions. Series A. - : ROYAL SOC. - 1364-503X .- 1471-2962. ; 377:2160 Tidskriftsartikel (refereegranskat)abstract The use of classical regression techniques in social science can prevent the discovery of complex, nonlinear mechanisms and often relies too heavily on both the expertise and prior expectations of the data analyst. In this paper, we present a regression methodology that combines the interpretability of traditional, well used, statistical methods with the full predictability and flexibility of Bayesian statistics techniques. Our modelling approach allows us to find and explain the mechanisms behind the rise of Radical Right-wing Populist parties (RRPs) that we would have been unable to find using traditional methods. Using Swedish municipality-level data (2002-2018), we find no evidence that the proportion of foreign-born residents is predictive of increases in RRP support. Instead, education levels and population density are the significant variables that impact the change in support for the RRP, in addition to spatial and temporal control variables. We argue that our methodology, which produces models with considerably better fit of the complexity and nonlinearities often found in social systems, provides a better tool for hypothesis testing and exploration of theories about RRPs and other social movements. This article is part of the theme issue 'Coupling functions: dynamical interaction mechanisms in the physical, biological and social sciences'.
19.	Borgdorff, J., et al. (författare) Performance of distributed multiscale simulations 2014 Ingår i: Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. - : The Royal Society. - 1364-503X .- 1471-2962. ; 372:2021 Tidskriftsartikel (refereegranskat)abstract Multiscale simulations model phenomena across natural scales using monolithic or component-based code, running on local or distributed resources. In this work, we investigate the performance of distributed multiscale computing of component-based models, guided by six multiscale applications with different characteristics and from several disciplines. Three modes of distributed multiscale computing are identified: supplementing local dependencies with large-scale resources, load distribution over multiple resources, and load balancing of small- and large-scale resources. We find that the first mode has the apparent benefit of increasing simulation speed, and the second mode can increase simulation speed if local resources are limited. Depending on resource reservation and model coupling topology, the third mode may result in a reduction of resource consumption.
20.	Bostan, Lars, et al. (författare) Upscaling of lignin precursor melt spinning by bicomponent spinning and its use for carbon fibre production 2021 Ingår i: Philosophical Transactions. Series A. - : Royal Society Publishing. - 1364-503X .- 1471-2962. ; 379:2209 Tidskriftsartikel (refereegranskat)abstract Upscaling lignin-based precursor fibre production is an essential step in developing bio-based carbon fibre from renewable feedstock. The main challenge in upscaling of lignin fibre production by melt spinning is its melt behaviour and rheological properties, which differ from common synthetic polymers used in melt spinning. Here, a new approach in melt spinning of lignin, using a spin carrier system for producing bicomponent fibres, has been introduced. An ethanol extracted lignin fraction from LignoBoost process of commercial softwood kraft black liquor was used as feedstock. After additional heat treatment, melt spinning was performed in a pilot-scale spinning unit. For the first time, biodegradable polyvinyl alcohol (PVA) was used as a spin carrier to enable the spinning of lignin by improving the required melt strength. PVA-sheath/lignin-core bicomponent fibres were manufactured. Afterwards, PVA was dissolved by washing with water. Pure lignin fibres were stabilized and carbonized, and tensile properties were measured. The measured properties, tensile modulus of 81.1 ± 3.1 GPa and tensile strength of 1039 ± 197 MPa, are higher than the majority of lignin-based carbon fibres reported in the literature. This new approach can significantly improve the melt spinning of lignin and solve problems related to poor spinnability of lignin and results in the production of high-quality lignin-based carbon fibres. This article is part of the theme issue 'Bio-derived and bioinspired sustainable advanced materials for emerging technologies (part 2)'. © 2021 The Author(s).
21.	Breton, Simon-Philippe, et al. (författare) A survey of modelling methods for high-fidelity wind farm simulations using large eddy simulation 2017 Ingår i: Philosophical Transactions. Series A. - : ROYAL SOC. - 1364-503X .- 1471-2962. ; 375:2091 Forskningsöversikt (refereegranskat)abstract Large eddy simulations (LES) of wind farms have the capability to provide valuable and detailed information about the dynamics of wind turbine wakes. For this reason, their use within the wind energy research community is on the rise, spurring the development of new models and methods. This review surveys the most common schemes available to model the rotor, atmospheric conditions and terrain effects within current state-of-the-art LES codes, of which an overview is provided. A summary of the experimental research data available for validation of LES codes within the context of single and multiple wake situations is also supplied. Some typical results for wind turbine and wind farm flows are presented to illustrate best practices for carrying out high-fidelity LES of wind farms under various atmospheric and terrain conditions. This article is part of the themed issue 'Wind energy in complex terrains'.
22.	Caffarelli, Luis A., et al. (författare) Regularity of free boundaries a heuristic retro 2015 Ingår i: Philosophical Transactions. Series A. - : The Royal Society. - 1364-503X .- 1471-2962. ; 373:2050 Forskningsöversikt (refereegranskat)abstract This survey concerns regularity theory of a few free boundary problems that have been developed in the past half a century. Our intention is to bring up different ideas and techniques that constitute the fundamentals of the theory. We shall discuss four different problems, where approaches are somewhat different in each case. Nevertheless, these problems can be divided into two groups: (i) obstacle and thin obstacle problem; (ii) minimal surfaces, and cavitation flow of a perfect fluid. In each case, we shall only discuss the methodology and approaches, giving basic ideas and tools that have been specifically designed and tailored for that particular problem. The survey is kept at a heuristic level with mainly geometric interpretation of the techniques and situations in hand.
23.	Chafik, Léon, 1985-, et al. (författare) Observed mechanisms activating the recent subpolar North Atlantic Warming since 2016 2023 Ingår i: Philosophical Transactions. Series A. - 1364-503X .- 1471-2962. ; 381:2262 Tidskriftsartikel (refereegranskat)abstract The overturning circulation of the subpolar North Atlantic (SPNA) plays a fundamental role in Earth's climate variability and change. Here, we show from observations that the recent warming period since about 2016 in the eastern SPNA involves increased western boundary density at the intergyre boundary, likely due to enhanced buoyancy forcing as a response to the strong increase in the North Atlantic Oscillation since the early 2010s. As these deep positive density anomalies spread southward along the western boundary, they enhance the North Atlantic Current and associated meridional heat transport at the intergyre region, leading to increased influx of subtropical heat into the eastern SPNA. Based on the timing of this chain of events, we conclude that this recent warming phase since about 2016 is primarily associated with this observed mechanism of changes in deep western boundary density, an essential element in these interactions.This article is part of a discussion meeting issue 'Atlantic overturning: new observations and challenges'.
24.	Charette, M, et al. (författare) Coastal ocean and shelf-sea biogeochemical cycling of trace elements and isotopes: lessons learned from GEOTRACES 2016 Ingår i: Philosopical Transactions of the Royal Society A. - : The Royal Society. - 1364-503X. ; 374:2081 Forskningsöversikt (refereegranskat)abstract Continental shelves and shelf seas play a central role in the global carbon cycle. However,their importance with respect to trace element and isotope (TEI) inputs to ocean basinsis less well understood. Here, we present major findings on shelf TEI biogeochemistryfrom the GEOTRACES programme as well as a proof of concept for a new method toestimate shelf TEI fluxes. The case studies focus on advances in our understanding of TEIcycling in the Arctic, transformations within a major river estuary (Amazon), shelf sedimentmicronutrient fluxes and basin-scale estimates of submarine groundwater discharge. Theproposed shelf flux tracer is 228-radium (T1/2 =5.75 yr), which is continuously supplied tothe shelf from coastal aquifers, sediment porewater exchange and rivers. Model-derived shelf228Ra fluxes are combined with TEI/ 228Ra ratios to quantify ocean TEI fluxes from thewestern North Atlantic margin. The results from this new approach agree well with previousestimates for shelf Co, Fe, Mn and Zn inputs and exceed published estimates of atmosphericdeposition by factors of approximately 3–23. Lastly, recommendations are made for additionalGEOTRACES process studies and coastal margin-focused section cruises that will help refinethe model and provide better insight on the mechanisms driving shelf-derived TEI fluxesto the ocean.This article is part of the themed issue ‘Biological and climatic impacts of ocean trace elementchemistry’.
25.	Chen, Gui-Qiang, et al. (författare) Free boundary problems : the forefront of current and future developments 2015 Ingår i: Philosophical Transactions. Series A. - : The Royal Society. - 1364-503X .- 1471-2962. ; 373:2050 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
26.	Cho, Daeheum, et al. (författare) Imaging of transition charge densities involving carbon core excitations by all X-ray sum-frequency generation 2019 Ingår i: Philosophical Transactions. Series A. - : The Royal Society. - 1364-503X .- 1471-2962. ; 377:2145 Tidskriftsartikel (refereegranskat)abstract X-ray diffraction signals from the time-evolving molecular charge density induced by selective core excitation of chemically inequivalent carbon atoms are calculated. A narrowband X-ray pulse selectively excites the carbon K-edge of the –CH3 or –CH2F groups in fluoroethane (CH3–CH2F). Each excitation creates a distinct core coherence which depends on the character of the electronic transition. Direct propagation of the reduced single-electron density matrix, using real-time time-dependent density functional theory, provides the time-evolving charge density following interactions with external fields. The interplay between partially filled valence molecular orbitals upon core excitation induces characteristic femtosecond charge migration which depends on the core–valence coherence, and is monitored by the sum-frequency generation diffraction signal.
27.	Christensen, Torben, et al. (författare) A catchment-scale carbon and greenhouse gas budget of a subartic landscape 2007 Ingår i: Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Science. - : The Royal Society. - 1364-503X .- 1471-2962. ; 365:1856, s. 1643-1656 Tidskriftsartikel (refereegranskat)abstract This is the first attempt to budget average current annual carbon (C) and associated greenhouse gas (GHG) exchanges and transfers in a subarctic landscape, the Lake Torneträsk catchment in northern Sweden. This is a heterogeneous area consisting of almost 4000 km2 of mixed heath, birch and pine forest, and mires, lakes and alpine ecosystems. The magnitudes of atmospheric exchange of carbon in the form of the GHGs, CO2 and CH4 in these various ecosystems differ significantly, ranging from little or no flux in barren ecosystems over a small CO2 sink function and low rates of CH4 exchange in the heaths to significant CO2 uptake in the forests and also large emissions of CH4 from the mires and small lakes. The overall catchment budget, given the size distribution of the individual ecosystem types and a first approximation of run-off as dissolved organic carbon, reveals a landscape currently with a significant sink capacity for atmospheric CO2. This sink capacity is, however, extremely sensitive to environmental changes, particularly those that affect the birch forest ecosystem. Climatic drying or wetting and episodic events such as insect outbreaks may cause significant changes in the sink function. Changes in the sources of CH4 through increased permafrost melting may also easily change the sign of the current radiative forcing, due to the stronger impact per gram of CH4 relative to CO2. Hence, to access impacts on climate, the atmospheric C balance alone has to be weighed in a radiative forcing perspective. When considering the emissions of CH4 from the mires and lakes as CO2 equivalents, the Torneträsk catchment is currently a smaller sink of radiative forcing, but it can still be estimated as representing the equivalent of approximately 14 000 average Swedish inhabitants' emissions of CO2. This can be compared with the carbon emissions of less than 200 people who live permanently in the catchment, although this comparison disregards substantial emissions from the non-Swedish tourism and transportation activities.
28.	Church, Ross, et al. (författare) Properties of long gamma-ray bursts from massive compact binaries. 2013 Ingår i: Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Science. - : The Royal Society. - 1364-503X .- 1471-2962. ; 371:1992 Tidskriftsartikel (refereegranskat)abstract We consider the implications of a model for long-duration gamma-ray bursts in which the progenitor is spun up in a close binary by tidal interactions with a massive black-hole companion. We investigate a sample of such binaries produced by a binary population synthesis, and show that the model predicts several common features in the accretion on to the newly formed black hole. In all cases, the accretion rate declines as approximately t(-5/3) until a break at a time of order 10(4) s. The accretion rate declines steeply thereafter. Subsequently, there is flaring activity, with the flare peaking between 10(4) and 10(5) s, the peak time being correlated with the flare energy. We show that these times are set by the semi-major axis of the binary, and hence the process of tidal spin-up; furthermore, they are consistent with flares seen in the X-ray light curves of some long gamma-ray bursts.
29.	Coates, C. S., et al. (författare) Ferroic multipolar order and disorder in cyanoelpasolite molecular perovskites 2019 Ingår i: Philosophical Transactions. Series A. - : ROYAL SOC. - 1364-503X .- 1471-2962. ; 377:2149 Tidskriftsartikel (refereegranskat)abstract We use a combination of variable-temperature highresolution synchrotron X-ray powder diffraction measurements and Monte Carlo simulations to characterize the evolution of two different types of ferroic multipolar order in a series of cyanoelpasolite molecular perovskites. We show that ferroquadrupolar order in [C3N2H5](2)Rb[Co(CN)(6)] is a first-order process that is well described by a fourstate Potts model on the simple cubic lattice. Likewise, ferrooctupolar order in [NMe4](2)B[Co(CN)(6)] (B= K, Rb, Cs) also emerges via a first-order transition that now corresponds to a six-state Potts model. Hence, for these particular cases, the dominant symmetry breaking mechanisms are well understood in terms of simple statistical mechanical models. By varying composition, we find that the effective coupling between multipolar degrees of freedom- and hence the temperature at which ferromultipolar order emerges-can be tuned in a chemically sensible manner. This article is part of the theme issue 'Mineralomimesis: natural and synthetic frameworks in science and technology'.
30.	Constantin, Adrian (författare) Introduction: some recent developments of nonlinear water wave theory 2007 Ingår i: Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Science. - : The Royal Society. - 1364-503X .- 1471-2962. ; 365:1858, s. 2195-2201 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract The opening article of this issue is intended to provide a review of some relevant topics of the mathematical theory of water waves that have recently received considerable attention in the research literature. We also provide a brief discussion about the content and contribution of the articles that make up this issue.
31.	Constantin, Adrian, et al. (författare) Rotational steady water waves near stagnation 2007 Ingår i: Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Science. - : The Royal Society. - 1364-503X .- 1471-2962. ; 365:1858, s. 2227-2239 Tidskriftsartikel (refereegranskat)abstract We investigate the location of the point of maximal horizontal velocity for steady periodic water waves with vorticity.
32.	Curia, S., et al. (författare) Green process for green materials : viable low-temperature lipase-catalysed synthesis of renewable telechelics in supercritical CO2 2015 Ingår i: Philosophical Transactions. Series A. - : Royal Society of London. - 1364-503X .- 1471-2962. ; 373:2057 Tidskriftsartikel (refereegranskat)abstract We present a novel near-ambient-temperature approach to telechelic renewable polyesters by exploiting the unique properties of supercritical CO2 (scCO(2)). Bio-based commercially available monomers have been polymerized and functional telechelic materials with targeted molecular weight prepared by end-capping the chains with molecules containing reactive moieties in a one-pot reaction. The use of scCO(2) as a reaction medium facilitates the effective use of Candida antarctica Lipase B (CaLB) as a catalyst at a temperature as low as 35 degrees C, hence avoiding side reactions, maintaining the end-capper functionality and preserving the enzyme activity. The functionalized polymer products have been characterized by H-1 nuclear magnetic resonance spectroscopy, matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry, gel permeation chromatography and differential scanning calorimetry in order to carefully assess their structural and thermal properties. We demonstrate that telechelic materials can be produced enzymatically at mild temperatures, in a solvent-free system and using renewably sourced monomers without pre-modification, by exploiting the unique properties of scCO(2). The macromolecules we prepare are ideal green precursors that can be further reacted to prepare useful bio-derived films and coatings.
33.	Daly, T., et al. (författare) Modelling of the flow field surrounding tidal turbine arrays for varying positions in a channel 2013 Ingår i: Philosophical Transactions. Series A. - : The Royal Society. - 1364-503X .- 1471-2962. Tidskriftsartikel (refereegranskat)abstract The modelling of tidal turbines and the hydrodynamic effects of tidal power extraction represents a relatively new challenge in the field of computational fluid dynamics. Many different methods of defining flow and boundary conditions have been postulated and examined to determine how accurately they replicate the many parameters associated with tidal power extraction. This paper outlines the results of numerical modelling analysis carried out to investigate different methods of defining the inflow velocity boundary condition. This work is part of a wider research programme investigating flow effects in tidal turbine arrays. Results of this numerical analysis were benchmarked against previous experimental work conducted at the University of Southampton Chilworth hydraulics laboratory. Results show significant differences between certain methods of defining inflow velocities. However, certain methods do show good correlation with experimental results. This correlation would appear to justify the use of these velocity inflow definition methods in future numerical modelling of the far-field flow effects of tidal turbine arrays.
34.	Dandouras, Iannis, et al. (författare) Titan's exosphere and its interaction with Saturn's magnetosphere 2009 Ingår i: Philosophical Transactions. Series A. - : The Royal Society. - 1364-503X .- 1471-2962. ; 367:1889, s. 743-752 Tidskriftsartikel (refereegranskat)abstract Titan's nitrogen-rich atmosphere is directly bombarded by energetic ions, due to its lack of a significant intrinsic magnetic field. Singly charged energetic ions from Saturn's magnetosphere undergo charge-exchange collisions with neutral atoms in Titan's upper atmosphere, or exosphere, being transformed into energetic neutral atoms (ENAs). The ion and neutral camera, one of the three sensors that comprise the magnetosphere imaging instrument (MIMI) on the Cassini/Huygens mission to Saturn and Titan, images these ENAs like photons, and measures their fluxes and energies. These remote-sensing measurements, combined with the in situ measurements performed in the upper thermosphere and in the exosphere by the ion and neutral mass spectrometer instrument, provide a powerful diagnostic of Titan's exosphere and its interaction with the Kronian magnetosphere. These observations are analysed and some of the exospheric features they reveal are modelled.
35.	D'Ariano, Giacomo Mauro, et al. (författare) Preface of the special issue quantum foundations : information approach 2016 Ingår i: Philosophical Transactions. Series A. - : The Royal Society. - 1364-503X .- 1471-2962. ; 374:2068 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract This special issue is based on the contributions of a group of top experts in quantum foundations and quantum information and probability. It enlightens a number of interpretational, mathematical and experimental problems of quantum theory.
36.	Davidson, Lars, 1957 (författare) Hybrid LES-RANS: back scatter from a scale-similarity model used as forcing 2009 Ingår i: Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. - : The Royal Society. - 1364-503X .- 1471-2962. ; 367:1899, s. 2905-2915 Tidskriftsartikel (refereegranskat)abstract A dissipative scale-similarity subgrid model was recently proposed in which only the dissipative part of the subgrid stresses was added to the momentum equations. This was achieved by adding the gradient of a subgrid stress only when its sign agreed with that of the corresponding viscous term. In the present work, this idea is used the other way around as forcing in hybrid large eddy simulation-Reynolds-averaged Navier-Stokes: only the part of a subgrid stress term that corresponds to back scatter is added to the momentum equations. The forcing triggers resolved turbulence in the transition region between the unsteady Reynolds-averaged Navier-Stokes and large eddy simulation regions. The new approach is evaluated for fully developed channel flow at Re(tau) = 4000. It is found that the forcing indeed does increase the resolved turbulence in the transition region. The magnitude of the production (i.e. back scatter) due to forcing in the equation for resolved kinetic energy is of the order of that due to the usual strain-rate production term. The present approach of using back scatter from a scale-similarity model can also probably be useful for triggering transition.
37.	Delvenne, Jean-Charles, et al. (författare) Dissipative open systems theory as a foundation for the thermodynamics of linear systems 2017 Ingår i: Philosophical Transactions. Series A. - : The Royal Society. - 1364-503X .- 1471-2962. ; 375:2088 Tidskriftsartikel (refereegranskat)abstract In this paper, we advocate the use of open dynamical systems, i.e. systems sharing input and output variables with their environment, and the dissipativity theory initiated by Jan Willems as models of thermodynamical systems, at the microscopic and macroscopic level alike. We take linear systems as a study case, where we show how to derive a global Lyapunov function to analyse networks of interconnected systems. We define a suitable notion of dynamic non-equilibrium temperature that allows us to derive a discrete Fourier law ruling the exchange of heat between lumped, discrete-space systems, enriched with the Maxwell-Cattaneo correction. We complete these results by a brief recall of the steps that allow complete derivation of the dissipation and fluctuation in macroscopic systems (i.e. at the level of probability distributions) from lossless and deterministic systems. This article is part of the themed issue 'Horizons of cybernetical physics'.
38.	Dutta, Prabal, et al. (författare) Operating systems and network protocols for wireless sensor networks 2012. - 7 Ingår i: Philosophical Transactions of the Royal Society A: Mathematical Physical & Engineering Sciences. - : The Royal Society. - 1364-503X .- 1471-2962. ; 370 Tidskriftsartikel (refereegranskat)abstract Sensor network protocols exist to satisfy the communication needs of diverse applications, including data collection, event detection, target tracking and control. Network protocols to enable these services are constrained by the extreme resource scarcity of sensor nodes—including energy, computing, communications and storage—which must be carefully managed and multiplexed by the operating system. These challenges have led to new protocols and operating systems that are efficient in their energy consumption, careful in their computational needs and miserly in their memory footprints, all while discovering neighbours, forming networks, delivering data and correcting failures.
39.	Ehrenfreund, Pascale, et al. (författare) The evolution of organic matter in space 2011 Ingår i: Philosophical Transactions. Series A. - London : The Royal Society. - 1364-503X .- 1471-2962. ; 369:1936, s. 538-554 Tidskriftsartikel (refereegranskat)abstract Carbon, and molecules made from it, have already been observed in the early Universe. During cosmic time, many galaxies undergo intense periods of star formation, during which heavy elements like carbon, oxygen, nitrogen, silicon and iron are produced. Also, many complex molecules, from carbon monoxide to polycyclic aromatic hydrocarbons, are detected in these systems, like they are for our own Galaxy. Interstellar molecular clouds and circumstellar envelopes are factories of complex molecular synthesis. A surprisingly high number of molecules that are used in contemporary biochemistry on the Earth are found in the interstellar medium, planetary atmospheres and surfaces, comets, asteroids and meteorites and interplanetary dust particles. Large quantities of extra-terrestrial material were delivered via comets and asteroids to young planetary surfaces during the heavy bombardment phase. Monitoring the formation and evolution of organic matter in space is crucial in order to determine the prebiotic reservoirs available to the early Earth. It is equally important to reveal abiotic routes to prebiotic molecules in the Earth environments. Materials from both carbon sources (extra-terrestrial and endogenous) may have contributed to biochemical pathways on the Earth leading to life’s origin. The research avenues discussed also guide us to extend our knowledge to other habitable worlds.
40.	Field, A. R., et al. (författare) Comparing pedestal structure in JET-ILW H-mode plasmas with a model for stiff ETG turbulent heat transport 2023 Ingår i: Philosophical Transactions. Series A. - : The Royal Society. - 1364-503X .- 1471-2962. ; 381:2242 Tidskriftsartikel (refereegranskat)abstract A predictive model for the electron temperature profile of the H-mode pedestal is described, and its results are compared with the pedestal structure of JET-ILW plasmas. The model is based on a scaling for the gyro-Bohm normalized, turbulent electron heat flux qe/qe,gB resulting from electron temperature gradient (ETG) turbulence, derived from results of nonlinear gyrokinetic (GK) calculations for the steep gradient region. By using the local temperature gradient scale length L-Te in the normalization, the dependence of q(e)/q(e,g)B on the normalized gradients R/L-Te and R/(Lne) can be represented by a unified scaling with the parameter eta(e) = L-ne/L-Te, to which the linear stability of ETG turbulence is sensitive when the density gradient is sufficiently steep. For a prescribed density profile, the value of R/L-Te determined from this scaling, required to maintain a constant electron heat flux qe across the pedestal, is used to calculate the temperature profile. Reasonable agreement with measurements is found for different cases, the model providing an explanation of the relative widths and shifts of the T-e and n(e) profiles, as well as highlighting the importance of the separatrix boundary conditions. Other cases showing disagreement indicate conditions where other branches of turbulence might dominate.This article is part of a discussion meeting issue "H-mode transition and pedestal studies in fusion plasmas'.
41.	Figalli, Alessio, et al. (författare) An overview of unconstrained free boundary problems 2015 Ingår i: Philosophical Transactions. Series A. - : The Royal Society. - 1364-503X .- 1471-2962. ; 373:2050 Tidskriftsartikel (refereegranskat)abstract In this paper, we present a survey concerning unconstrained free boundary problems of type F-1(D(2)u, del u, u, x) = 0 in B-1 boolean AND Omega, F-2(D(2)u, del u, u, x) = 0 in B-1 \ Omega, u is an element of S(B-1), where B-1 is the unit ball, Omega is an unknown open set, F-1 and F-2 are elliptic operators (admitting regular solutions), and S is a functions space to be specified in each case. Our main objective is to discuss a unifying approach to the optimal regularity of solutions to the above matching problems, and list several open problems in this direction.
42.	Flammini, Francesco, Senior Lecturer, 1978- (författare) Digital twins as run-time predictive models for the resilience of cyber-physical systems : a conceptual framework 2021 Ingår i: Philosophical Transactions. Series A. - : ROYAL SOC. - 1364-503X .- 1471-2962. ; 379:2207 Tidskriftsartikel (refereegranskat)abstract Digital twins (DT) are emerging as an extremely promising paradigm for run-time modelling and performability prediction of cyber-physical systems (CPS) in various domains. Although several different definitions and industrial applications of DT exist, ranging from purely visual three-dimensional models to predictive maintenance tools, in this paper, we focus on data-driven evaluation and prediction of critical dependability attributes such as safety. To that end, we introduce a conceptual framework based on autonomic systems to host DT run-time models based on a structured and systematic approach. We argue that the convergence between DT and self-adaptation is the key to building smarter, resilient and trustworthy CPS that can self-monitor, self-diagnose and-ultimately-self-heal. The conceptual framework eases dependability assessment, which is essential for the certification of autonomous CPS operating with artificial intelligence and machine learning in critical applications. This article is part of the theme issue 'Towards symbiotic autonomous systems'.
43.	Futter, Martyn (författare) A cost-effectiveness analysis of water security and water quality: impacts of climate and land-use change on the River Thames system 2013 Ingår i: Philosophical Transactions A: Mathematical, Physical and Engineering Sciences. - : The Royal Society. - 1364-503X .- 1471-2962. ; 371 Tidskriftsartikel (refereegranskat)abstract The catchment of the River Thames, the principal river system in southern England, provides the main water supply for London but is highly vulnerable to changes in climate, land use and population. The river is eutrophic with significant algal blooms with phosphorus assumed to be the primary chemical indicator of ecosystem health. In the Thames Basin, phosphorus is available from point sources such as wastewater treatment plants and from diffuse sources such as agriculture. In order to predict vulnerability to future change, the integrated catchments model for phosphorus (INCA-P) has been applied to the river basin and used to assess the cost-effectiveness of a range of mitigation and adaptation strategies. It is shown that scenarios of future climate and land-use change will exacerbate the water quality problems, but a range of mitigation measures can improve the situation. A cost-effectiveness study has been undertaken to compare the economic benefits of each mitigation measure and to assess the phosphorus reductions achieved. The most effective strategy is to reduce fertilizer use by 20% together with the treatment of effluent to a high standard. Such measures will reduce the instream phosphorus concentrations to close to the EU Water Framework Directive target for the Thames.
44.	George, William, 1945 (författare) Is there a universal log law for turbulent wall-bounded flows? 2007 Ingår i: Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. - : The Royal Society. - 1364-503X .- 1471-2962. ; 365:1852, s. 789-806 Tidskriftsartikel (refereegranskat)abstract The history and theory supporting the idea of a universal log law for turbulent wall-bounded flows are briefly reviewed. The original idea of justifying a log law from a constant Reynolds stress layer argument is found to be deficient. By contrast, it is argued that the logarithmic friction law and velocity profiles derived from matching inner and outer profiles for a pipe or channel flow are well-founded and consistent with the data. But for a boundary layer developing along a. at plate it is not, and in fact it is a power law theory that seems logically consistent. Even so, there is evidence for at least an empirical logarithmic fit to the boundary-friction data, which is indistinguishable from the power law solution. The value of kappa approximate to 0.38 obtained from a logarithmic curve fit to the boundary-layer velocity data, however, does not appear to be the same as for pipe flow for which 0.43 appears to be the best estimate. Thus, the idea of a universal log law for wall-bounded flows is not supported by either the theory or the data.
45.	George, William, 1945, et al. (författare) Mind the gap: a guideline for large eddy simulation 2009 Ingår i: Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. - : The Royal Society. - 1364-503X .- 1471-2962. ; 367:1899, s. 2839-2847 Tidskriftsartikel (refereegranskat)abstract This paper briefly reviews some of the fundamental ideas of turbulence as they relate to large eddy simulation (LES). Of special interest is how our thinking about the so-called 'spectral gap' has evolved over the past decade, and what this evolution implies for LES applications.
46.	Gerin, M., et al. (författare) Hydride spectroscopy of the diffuse interstellar medium: new clues on the gas fraction in molecular form and cosmic ray ionization rate in relation to H-3(+) 2012 Ingår i: Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. - : The Royal Society. - 1364-503X .- 1471-2962. ; 370:1978, s. 5174-5185 Tidskriftsartikel (refereegranskat)abstract The Herschel-guaranteed time key programme PRobing InterStellar Molecules with Absorption line Studies (PRISMAS)(1) is providing a survey of the interstellar hydrides containing the elements C, O, N, F and Cl. As the building blocks of interstellar molecules, hydrides provide key information on their formation pathways. They can also be used as tracers of important physical and chemical properties of the interstellar gas that are difficult to measure otherwise. This paper presents an analysis of two sight-lines investigated by the PRISMAS project, towards the star-forming regions W49N and W51. By combining the information extracted from the detected spectral lines, we present an analysis of the physical properties of the diffuse interstellar gas, including the electron abundance, the fraction of gas in molecular form, and constraints on the cosmic ray ionization rate and the gas density.
47.	German, C, et al. (författare) Hydrothermal impacts on trace element and isotope ocean biogeochemistry 2016 Ingår i: Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. - : The Royal Society. - 1364-503X .- 1471-2962. ; 374:2081 Tidskriftsartikel (refereegranskat)abstract Hydrothermal activity occurs in all ocean basins, releasing high concentrations of key trace elements and isotopes (TEIs) into the oceans. Importantly, the calculated rate of entrainment of the entire ocean volume through turbulently mixing buoyant hydrothermal plumes is so vigorous as to be comparable to that of deep-ocean thermohaline circulation. Consequently, biogeochemical processes active within deep-ocean hydrothermal plumes have long been known to have the potential to impact global-scale biogeochemical cycles. More recently, new results from GEOTRACES have revealed that plumes rich in dissolved Fe, an important micronutrient that is limiting to productivity in some areas, are widespread above mid-ocean ridges and extend out into the deep-ocean interior. While Fe is only one element among the full suite of TEIs of interest to GEOTRACES, these preliminary results are important because they illustrate how inputs from seafloor venting might impact the global biogeochemical budgets of many other TEIs. To determine the global impact of seafloor venting, however, requires two key questions to be addressed: (i) What processes are active close to vent sites that regulate the initial high-temperature hydrothermal fluxes for the full suite of TEIs that are dispersed through non-buoyant hydrothermal plumes? (ii) How do those processes vary, globally, in response to changing geologic settings at the seafloor and/or the geochemistry of the overlying ocean water? In this paper, we review key findings from recent work in this realm, highlight a series of key hypotheses arising from that research and propose a series of new GEOTRACES modelling, section and process studies that could be implemented, nationally and internationally, to address these issues. This article is part of the themed issue ‘Biological and climatic impacts of ocean trace element chemistry’.
48.	Geyer, Anna, et al. (författare) Shallow water equations for equatorial tsunami waves 2018 Ingår i: Philosophical Transactions. Series A. - : The Royal Society. - 1364-503X .- 1471-2962. ; 376:2111 Tidskriftsartikel (refereegranskat)abstract We present derivations of shallow water model equations of Korteweg-de Vries and Boussinesq type for equatorial tsunami waves in the f-plane approximation and discuss their applicability. This article is part of the theme issue 'Nonlinear water waves'.
49.	Ginis, V., et al. (författare) Transformation optics beyond the manipulation of light trajectories 2015 Ingår i: Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. - : The Royal Society. - 1364-503X .- 1471-2962. ; 373:2049 Tidskriftsartikel (refereegranskat)abstract Since its inception in 2006, transformation optics has become an established tool to understand and design electromagnetic systems. It provides a geometrical perspective into the properties of light waves without the need for a ray approximation. Most studies have focused on modifying the trajectories of light rays, e.g. beam benders, lenses, invisibility cloaks, etc. In this contribution, we explore transformation optics beyond the manipulation of light trajectories. With a few well-chosen examples, we demonstrate that transformation optics can be used to manipulate electromagnetic fields up to an unprecedented level. In the first example, we introduce an electromagnetic cavity that allows for deep subwavelength confinement of light. The cavity is designed with transformation optics even though the concept of trajectory ceases to have any meaning in a structure as small as this cavity. In the second example, we show that the properties of Cherenkov light emitted in a transformationoptical material can be understood and modified from simple geometric considerations. Finally, we show that optical forces-a quadratic function of the fields-follow the rules of transformation optics too. By applying a folded coordinate transformation to a pair of waveguides, optical forces can be enhanced just as if the waveguides were closer together. With these examples, we open up an entirely new spectrum of devices that can be conceived using transformation optics.
50.	Grandfield, Kathryn, et al. (författare) High-resolution three-dimensional probes of biomaterials and their interfaces. 2012 Ingår i: Philosophical transactions. Series A, Mathematical, physical, and engineering sciences. - : The Royal Society. - 1364-503X .- 1471-2962. ; 370:1963, s. 1337-51 Tidskriftsartikel (refereegranskat)abstract Interfacial relationships between biomaterials and tissues strongly influence the success of implant materials and their long-term functionality. Owing to the inhomogeneity of biological tissues at an interface, in particular bone tissue, two-dimensional images often lack detail on the interfacial morphological complexity. Furthermore, the increasing use of nanotechnology in the design and production of biomaterials demands characterization techniques on a similar length scale. Electron tomography (ET) can meet these challenges by enabling high-resolution three-dimensional imaging of biomaterial interfaces. In this article, we review the fundamentals of ET and highlight its recent applications in probing the three-dimensional structure of bioceramics and their interfaces, with particular focus on the hydroxyapatite-bone interface, titanium dioxide-bone interface and a mesoporous titania coating for controlled drug release.

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