Showing papers by "King's College, Aberdeen published in 2017"
TL;DR: The properties of nanoparticles and its aggregation as well as convective heat transfer of nanofluids have received great attentions over the last few decades as discussed by the authors, and the recent investigations on the fractal models and fractal-based approaches are summarized.
146 citations
TL;DR: The CURIOS (Cultural Repositories and Information Systems) project as mentioned in this paper explores two case studies in rural Scotland asking how community activity, connectivity and digital archives can support interest in local heritage as well as help develop more resilient communities.
82 citations
TL;DR: In this article, a two-degree-of-freedom wake oscillator model is proposed to describe vortex-induced vibrations of elastically supported cylinders capable of moving in cross-flow and in-line directions.
67 citations
TL;DR: In this article, a tensile stress is applied remotely on the free end of the fibril whose other end adheres to a rigid substrate, and the resulting adhesion of such structures were numerically investigated under plane strain ( 2 D ) and axisymmetric ( 3 D ) conditions.
Abstract: Bio-inspired fibrillar surfaces with reversible adhesion to stiff substrates have been thoroughly investigated over the last decade. In this paper we propose a novel composite fibril consisting of a soft tip layer and stiffer stalk with differently shaped interfaces (flat vs. curved) between them. A tensile stress is applied remotely on the free end of the fibril whose other end adheres to a rigid substrate. The stress distributions and the resulting adhesion of such structures were numerically investigated under plane strain ( 2 D ) and axisymmetric ( 3 D ) conditions. The stress intensities were evaluated for different combinations of layer thickness and Young’s moduli. The adhesion strength values were found to increase for thinner layers and larger modulus ratio; these trends are also reflected in selected experimental results. The results of this paper provide a new strategy for optimizing adhesion strength of fibrillar surfaces.
61 citations
TL;DR: Two contributions to search inefficiency are isolated: first, participants make superfluous fixations, sacrificing speed for a perceived (but not actual) gain in response certainty, and second, participants fixate the homogeneous side even more frequently than predicted by inefficient search of uniform arrays.
Abstract: Evolutionary pressures have made foraging behaviours highly efficient in many species. Eye movements during search present a useful instance of foraging behaviour in humans. We tested the efficiency of eye movements during search using homogeneous and heterogeneous arrays of line segments. The search target is visible in the periphery on the homogeneous array, but requires central vision to be detected on the heterogeneous array. For a compound search array that is heterogeneous on one side and homogeneous on the other, eye movements should be directed only to the heterogeneous side. Instead, participants made many fixations on the homogeneous side. By comparing search of compound arrays to an estimate of search performance based on uniform arrays, we isolate two contributions to search inefficiency. First, participants make superfluous fixations, sacrificing speed for a perceived (but not actual) gain in response certainty. Second, participants fixate the homogeneous side even more frequently than predicted by inefficient search of uniform arrays, suggesting they also fail to direct fixations to locations that yield the most new information.
53 citations
TL;DR: The results show that the high attenuation domain controls the largest monitored seismic, deformation, and geochemical unrest at the caldera.
Abstract: Despite their importance for eruption forecasting the causes of seismic rupture processes during caldera unrest are still poorly reconstructed from seismic images. Seismic source locations and waveform attenuation analyses of earthquakes in the Campi Flegrei area (Southern Italy) during the 1983–1984 unrest have revealed a 4–4.5 km deep NW-SE striking aseismic zone of high attenuation offshore Pozzuoli. The lateral features and the principal axis of the attenuation anomaly correspond to the main source of ground uplift during the unrest. Seismic swarms correlate in space and time with fluid injections from a deep hot source, inferred to represent geochemical and temperature variations at Solfatara. These swarms struck a high-attenuation 3–4 km deep reservoir of supercritical fluids under Pozzuoli and migrated towards a shallower aseismic deformation source under Solfatara. The reservoir became aseismic for two months just after the main seismic swarm (April 1, 1984) due to a SE-to-NW directed input from the high-attenuation domain, possibly a dyke emplacement. The unrest ended after fluids migrated from Pozzuoli to the location of the last caldera eruption (Mt. Nuovo, 1538 AD). The results show that the high attenuation domain controls the largest monitored seismic, deformation, and geochemical unrest at the caldera.
50 citations
03 Feb 2017
TL;DR: Compared to other knowledge-oriented information systems, the distinctive features of Knowledge Graphs lie in their special combination of knowledge representation structures, information management processes, and search algorithms.
Abstract: Compared to other knowledge-oriented information systems, the distinctive features of Knowledge Graphs lie in their special combination of knowledge representation structures, information management processes, and search algorithms.
45 citations
TL;DR: In this paper, the inverse opal structure was further investigated using carefully coupled experiments and finite element modeling, showing that the structure can achieve optimized specific strength and modulus, while simultaneously offering tunable optical bandgaps and large area fabrication.
40 citations
TL;DR: Findings elucidate when and how self-relevance influences decisional processing and hypothesized that temporal influences on self-construal may serve as an important determinant of stimulus prioritization.
Abstract: Recent research has revealed that self-referential processing enhances perceptual judgments — the so-called self-prioritization effect. The extent and origin of this effect remains unknown, however. Noting the multifaceted nature of the self, here we hypothesized that temporal influences on self-construal (i.e., past/future-self continuity) may serve as an important determinant of stimulus prioritization. Specifically, as representations of the self increase in abstraction as a function of temporal distance (i.e., distance from now), self-prioritization may only emerge when stimuli are associated with the current self. The results of three experiments supported this prediction. Self-relevance only enhanced performance in a standard perceptual-matching task when stimuli (i.e., geometric shapes) were connected with the current self; representations of the self in the future (Expts. 1 & 2) and past (Expt. 3) failed to facilitate decision making. To identify the processes underlying task performance, data were interrogated using a hierarchical drift diffusion model (HDDM) approach. Results of these analyses revealed that self-prioritization was underpinned by a stimulus bias (i.e., rate of information uptake). Collectively, these findings elucidate when and how self-relevance influences decisional processing.
39 citations
TL;DR: A dataset composed of Digital Terrain Models extracted from a total of 2,500 linear kilometres of high-resolution multibeam echosounder data collected in 2013 covering the entire network of tidal channels and inlets of the Venice Lagoon, Italy is released.
Abstract: Tidal channels are crucial for the functioning of wetlands, though their morphological properties, which are relevant for seafloor habitats and flow, have been understudied so far. Here, we release a dataset composed of Digital Terrain Models (DTMs) extracted from a total of 2,500 linear kilometres of high-resolution multibeam echosounder (MBES) data collected in 2013 covering the entire network of tidal channels and inlets of the Venice Lagoon, Italy. The dataset comprises also the backscatter (BS) data, which reflect the acoustic properties of the seafloor, and the tidal current fields simulated by means of a high-resolution three-dimensional unstructured hydrodynamic model. The DTMs and the current fields help define how morphological and benthic properties of tidal channels are affected by the action of currents. These data are of potential broad interest not only to geomorphologists, oceanographers and ecologists studying the morphology, hydrodynamics, sediment transport and benthic habitats of tidal environments, but also to coastal engineers and stakeholders for cost-effective monitoring and sustainable management of this peculiar shallow coastal system.
38 citations
TL;DR: A new convergence criterion for the SIMPLE algorithm, and more generally for the family of pressure-correction methods, is presented, based on satisfaction of bulk momentum balance, which makes it particularly useful for pore-scale modelling of reservoir rocks.
TL;DR: In this article, the formation of the youngest sapropel along an across-slope transect in the Adriatic Sea was investigated, and it was shown that the formation was synchronous with the deposition of south-eastern Mediterranean S1 beds.
TL;DR: In this paper, the significance of sandstone roll-front U deposits in an environmental and mineral exploration context is assessed, and the importance of these deposits in the absence of gamma signatures is discussed.
TL;DR: In this article, the authors integrated multiple regional datasets, including 3D seismic data and released commercial well logs, to detail the character and distribution of early Palaeogene tuffs in the offshore Faroe-Shetland Basin (FSB).
Abstract: Tuffs form key stratigraphic markers that assist with determining the timing of volcanic margin development. A number of laterally extensive tuffs are preserved along the North Atlantic Margin in the offshore Faroe–Shetland Basin (FSB), a product of early Palaeogene volcanism associated with the break-up and seafloor spreading between Greenland and NW Europe. These tuffs, which are dominantly basaltic in composition, are widely preserved in the contiguous North Sea Basin. However, less attention has been paid to them in the FSB. This study integrates multiple regional datasets, including 3D seismic data and released commercial well logs, to detail the character and distribution of early Palaeogene tuffs in the FSB. The earliest tuffs are more locally identified by their presence in core, whereas later tuffs are more regionally recognizable, highlighting more widespread volcanism with time. The distribution of tuffs also reveals the timing of formation of the previously enigmatic volcanic centres. Importantly, owing to constraints of vertical resolution in well data, we argue that the number of tuffs in the North Atlantic Margin is probably underestimated, and biased towards basaltic tuffs, which are easier to identify on well logs.
TL;DR: In this article, the seismic interpretation and image processing was carried out in the SeisLab facility at the University of Aberdeen (sponsored by BG BP and Chevron), and analysis of seismic amplitudes was performed in Petrel® 2016 (Schlumberger).
TL;DR: In this paper, the authors were partly supported by NSF grant DMS 1503044 and DMS 0953011, and the second author was partially supported by DMS 143044.
Abstract: The second author was partly supported by NSF grant DMS 1503044. The fourth author was partly supported by NSF grant DMS 0953011.
TL;DR: In this paper, a Dugdale-type analysis was used to predict the pull-off force of an elastic circular cylinder from a dissimilar substrate, with a cohesive zone of uniform tensile strength emanating from the interface corner.
Abstract: The adhesion of micron-scale surfaces due to intermolecular interactions is a subject of intense interest spanning electronics, biomechanics and the application of soft materials to engineering devices. The degree of adhesion is sensitive to the diameter of micro-pillars in addition to the degree of elastic mismatch between pillar and substrate. Adhesion-strength-controlled detachment of an elastic circular cylinder from a dissimilar substrate is predicted using a Dugdale-type of analysis, with a cohesive zone of uniform tensile strength emanating from the interface corner. Detachment initiates when the opening of the cohesive zone attains a critical value, giving way to crack formation. When the cohesive zone size at crack initiation is small compared to the pillar diameter, the initiation of detachment can be expressed in terms of a critical value Hc of the corner stress intensity. The estimated pull-off force is somewhat sensitive to the choice of stick/slip boundary condition used on the cohesive zone, especially when the substrate material is much stiffer than the pillar material. The analysis can be used to predict the sensitivity of detachment force to the size of pillar and to the degree of elastic mismatch between pillar and substrate.
TL;DR: In this paper, a discrete dislocation plasticity (DDP) analysis of the high temperature creep deformation of a single crystal Ni superalloy comprising Ni3Al precipitates in a Ni matrix (γ) is presented.
TL;DR: In this paper, the N.A.T. was partially supported by an NSERC Postdoctoral Fellowship and through the EPSRC grant EP/N00874X/1.
TL;DR: In this article, the Lie algebra structure of the first Hochschild cohomology of a class of quantum complete intersections over a field of odd prime characteristic p has been studied, and it has been shown that if B is a defect 2-block of a finite group algebra whose Brauer correspondent C has a unique isomorphism class of simple modules, then a basic algebra of B can be generated by at most 2√I elements.
TL;DR: The phase trajectory in the new composite hyper-chaotic multi-scroll attractor diverges in multiple eigen-directions, which improves the security of secure communication and chaotic encryption.
Abstract: Time delay feedback has been shown to produce chaos from non-chaotic systems. In this paper, besides the single and double scroll chaotic attractors, a new composite multi-scroll attractor is found in stable systems with time delay feedback. From the viewpoint of the local stability analysis, conservation analysis, Lyapunov exponent spectrum and power spectrum, the composite multi-scroll attractor is shown to be a hyper-chaotic attractor. The phase trajectory in the new composite hyper-chaotic multi-scroll attractor diverges in multiple eigen-directions, which improves the security of secure communication and chaotic encryption. A paradigm using the multi-scroll attractor for encryption is proposed, demonstrating its potential applicability.
TL;DR: In this article, the authors present the results of 15 different studies in the Black Sea-Caucasus segment of the Alpine-Tethys orogenic realm, focusing on the style and timing of key tectonic events occurring primarily during the area's post-Pangaean evolution.
Abstract: Abstract This Special Publication presents the results of 15 different studies in the Black Sea–Caucasus segment of the Alpine–Tethys orogenic realm. The main focus of these studies is the style and timing of key tectonic events occurring primarily during the area's post-Pangaean evolution. The methodologies encompass: geophysics, including active and passive crustal-scale seismology and common depth point reflection seismic profiling (both onshore and marine), palaeomagnetism and magnetostratigraphy; field geology, including biostratigraphic recorrelation; radiochronology; igneous rock geochemistry, including analyses of the obducted ophiolites; and low-temperature thermochronology. The geological record of the area is essentially one of sedimentary basins formed in an extensional back-arc setting and their subsequent compressional deformation during the closure of at least two branches of the Neotethys Ocean system.
TL;DR: Vigorito and Hurst as discussed by the authors described examples of sandstone intrusions from the Panoche Giant Injection Complex (PGIC), the largest known GSI, which has reserves in excess of 135 million bbl.
Abstract: Giant sand injection complexes (GSIs) are regionally developed in many petroleum systems and have become well known in deep-water clastic settings in the North Sea, California, offshore Angola, and elsewhere (Hurst and Cartwright, 2007; Huuse et al., 2010). The GSIs form during shallow burial (generally <1.5 km [0.93 mi]) when pore-fluid pressure rises rapidly to exceed the fracture and lithostatic gradients and regional hydraulic failure occurs in the host strata that causes fluidization and injection of sand into a propagating fracture system (Hurst et al., 2011). Once buried more deeply, these sandstone intrusions are significant reservoir targets that form intrusive traps (Hurst et al., 2006).
In deep-water clastic settings, the significance of sand injectites became apparent in the mid to late 1990s during the development of Harding field (Dixon et al., 1995). In 2002, the first deliberate exploration of part of a GSI target led to discovery of the Volund field, Norway (DeBoer et al., 2007; Hurst et al., 2016), which has reserves in excess of 135 million bbl. Despite their growing significance as reservoirs in petroleum systems globally, remarkably little regional-scale mapping of outcrop of GSIs is published. To some extent this reflects a paucity of excellent outcrop, but it also reflects some resistance to the notion that sandstone intrusions can contain commercially significant hydrocarbon volumes, which they clearly do (Hurst et al., 2005).
Here and in Vigorito and Hurst (2017) we describe examples of sandstone intrusions from the Panoche Giant Injection Complex (PGIC; Figure 1A, B), the largest known GSI. The PGIC may be unique, because in an area approaching 400 km2 (154 mi2) it has well-exposed relationships between the parent units from which sandstone intrusions emanate, an intrusive complex, and a paleoseafloor onto which sand extruded (Cima Lentil, Figure 1C; …
TL;DR: In this article, major funding was provided by the UK Natural Environment Research Council (NERC) under grant NE/I028017/1 and equipment was provided and supported by the NERC Geophysical Equipment Facility (SEIS-UK).
Abstract: Major funding was provided by the UK Natural Environment Research Council (NERC) under grant NE/I028017/1. Equipment was provided and supported by the NERC Geophysical Equipment Facility (SEIS-UK). This project is also supported by Bogazici University Scientific ˘ Research Projects (BAP) under grant 6922 and Turkish State Planning Organization (DPT) under the TAM project, number 2007K120610.
TL;DR: Conformal loop quantum gravity provides an approach to loop quantization through an underlying conformal structure ie conformally equivalent class of metrics The property that general relativity itself has no conformal invariance is reinstated with a constrained scalar field setting the physical scale as discussed by the authors.
Abstract: Conformal loop quantum gravity provides an approach to loop quantization through an underlying conformal structure ie conformally equivalent class of metrics The property that general relativity itself has no conformal invariance is reinstated with a constrained scalar field setting the physical scale Conformally equivalent metrics have recently been shown to be amenable to loop quantization including matter coupling It has been suggested that conformal geometry may provide an extended symmetry to allow a reformulated Immirzi parameter necessary for loop quantization to behave like an arbitrary group parameter that requires no further fixing as its present standard form does Here, we find that this can be naturally realized via conformal frame transformations in scalar-tensor gravity Such a theory generally incorporates a dynamical scalar gravitational field and reduces to general relativity when the scalar field becomes a pure gauge In particular, we introduce a conformal Einstein frame in which loop quantization is implemented We then discuss how different Immirzi parameters under this description may be related by conformal frame transformations and yet share the same quantization having, for example, the same area gaps, modulated by the scalar gravitational field
TL;DR: A uniform logical framework is described, based on a bunched logic that combines classical additives and very weak multiplicatives, for reasoning compositionally about access control policy models that provides a way to identify and reason about how vulnerabilities may arise (and be removed) as a result of the architecture of the system.
Abstract: We describe a uniform logical framework, based on a bunched logic that combines classical additives and very weak multiplicatives, for reasoning compositionally about access control policy models. We show how our approach takes account of the underlying system architecture, and so provides a way to identify and reason about how vulnerabilities may arise (and be removed) as a result of the architecture of the system. We consider, using frame rules, how local properties of access control policies are maintained as the system architecture evolves.
TL;DR: The work in this paper was supported by the Carnegie Trust for the Universities of Scotland (T.O.) and by the EPSRC GG-Top Project and the Cruickshank Trust (C.W.).
Abstract: This work was supported by the Carnegie Trust for the Universities of Scotland (T.O.) and by the EPSRC GG-Top Project and the Cruickshank Trust (C.W.).
24 Jan 2017
TL;DR: In the Digital and Information Age, companies and government agencies are highly digitalized, as the information exchanges happening in their processes, methods for organizing, finding, and selecting relevant information, beyond the capabilities of classic Information Retrieval are always active topics of research and development.
Abstract: In the Digital and Information Age, companies and government agencies are highly digitalized, as the information exchanges happening in their processes. They store information both as natural language text and structured data, e.g., relational databases or knowledge graphs. In this scenario, methods for organizing, finding, and selecting relevant information, beyond the capabilities of classic Information Retrieval, are always active topics of research and development.
TL;DR: Authigenic carbonates are frequently associated with methane cold-seep systems, which extensively occur in various geologic settings worldwide as mentioned in this paper, and the relation between the fluids involved in their formation and the isotopic signals recorded in the carbonate cements.
TL;DR: A simple, single formula is derived for the computation of RNL distance between two measurements of colour, equivalent to the published di-, tri- and tetrachromatic equations of Vorobyev and Osorio (1998), and valid for colour visual systems with any number of types of noisy photoreceptors.
Abstract: Researchers must assess similarities and differences in colour from an animal's eye view when investigating hypotheses in ecology, evolution and behaviour. Nervous systems generate colour perceptions by comparing the responses of different spectral classes of photoreceptor through colour opponent mechanisms, and the performance of these mechanisms is limited by photoreceptor noise. Accordingly, the receptor noise limited (RNL) colour distance model of Vorobyev and Osorio (Vorobyev & Osorio 1998 Proc. R. Soc. Lond. B265, 351-358 (doi:10.1098/rspb.1998.0302)) generates predictions about the discriminability of colours that agree with behavioural data, and consequently it has found wide application in studies of animal colour vision. Vorobyev and Osorio (1998) provide equations to calculate RNL colour distances for animals with di-, tri- and tetrachromatic vision, which is adequate for many species. However, researchers may sometimes wish to compute RNL colour distances for potentially more complex colour visual systems. Thus, we derive a simple, single formula for the computation of RNL distance between two measurements of colour, equivalent to the published di-, tri- and tetrachromatic equations of Vorobyev and Osorio (1998), and valid for colour visual systems with any number of types of noisy photoreceptors. This formula will allow the easy application of this important colour visual model across the fields of ecology, evolution and behaviour.