6,229 research outputs found
Short paper: From streaming data to linked data. A case study with bike sharing systems
Current methods and tools that support Linked Data publication have mainly focused so far on static data, without considering the growing amount of streaming data available on the Web. In this paper we describe a case study that involves the publication of static and streaming Linked Data for bike sharing systems and related entities. We describe some of the challenges that we have faced, the solutions that we have explored, the lessons that we have learned, and the opportunities that lie in the future for exploiting Linked Stream Data
Ophthalmoplegic Migraine and Infundibular Dilatation of a Cerebral Artery
Ophthalmoplegic migraine (OM) is a childhood disorder of uncertain etiology manifesting recurrent unilateral headache associated with a transitory oculomotor (usually IIIrd nerve) palsy. Recent publications emphasize the finding on MRI of contrast enhancement in the IIIrd nerve suggesting that OM may be a recurrent inflammatory neuropathy. We report the case of a 7-year-old boy with typical symptoms of this disorder. Angio MR and Angio CT revealed the presence of an infundibular dilatation of a perforating branch of the posterior cerebral artery adjacent to the symptomatic IIIrd nerve. We speculate that this and perhaps other cases of OM may have a different pathophysiology related to compression of the IIIrd nerve by an adjacent vascular structure that could activate the trigeminovascular system and produce migrainous pain
Symmetric vs asymmetric protection levels in SDC methods for tabular data
The final publication is available at link.springer.comProtection levels on sensitive cells—which are key parameters of any statistical disclosure control method for tabular data—are related to the difficulty of any attacker to recompute a good estimation of the true cell values. Those protection levels are two numbers (one for the lower protection, the other for the upper protection) imposing a safety interval around the cell value, that is, no attacker should be able to recompute an estimate within such safety interval. In the symmetric case the lower and upper protection levels are equal; otherwise they are referred as asymmetric protection levels. In this work we empirically study the effect of symmetry in protection levels for three protection methods: cell suppression problem (CSP), controlled tabular adjustment (CTA), and interval protection (IP). Since CSP and CTA are mixed integer linear optimization problems, it is seen that the symmetry (or not) of protection levels affect to the CPU time needed to compute a solution. For IP, a linear optimization problem, it is observed that the symmetry heavily affects to the quality of the solution provided rather than to the solution time.Peer ReviewedPostprint (author's final draft
A case study undertaken recycling & reuse of glass fiber reinforced thermoset polumer wastes of composite materials industry
Glass fibre-reinforced plastics (GFRP) have been considered inherently difficult to recycle due to both: crosslinked nature of thermoset resins, which cannot be remoulded, and complex composition of the composite itself.
Presently, most of the GFRP waste is landfilled leading to negative environmental impacts and supplementary added costs. With an increasing awareness of environmental matters and the subsequent desire to save resources, recycling would convert an expensive waste disposal into a profitable reusable material. In this study, efforts were made in order to recycle grinded GFRP waste, proceeding from pultrusion production scrap, into new and sustainable composite materials. For this purpose, GFRP waste recyclates, were incorporated into polyester based mortars as fine aggregate and filler replacements at different load contents and particle size distributions. Potential recycling solution was assessed by mechanical behaviour of resultant GFRP waste modified polymer mortars. Results revealed that GFRP waste filled polymer mortars present improved flexural and compressive behaviour over unmodified polyester based mortars, thus indicating the feasibility of the GFRP industrial waste reuse into concrete-polymer composite materials
Particle dynamics near extreme Kerr throat and supersymmetry
The extreme Kerr throat solution is believed to be non-supersymmetric.
However, its isometry group SO(2,1) x U(1) matches precisely the bosonic
subgroup of N=2 superconformal group in one dimension. In this paper we
construct N=2 supersymmetric extension of a massive particle moving near the
horizon of the extreme Kerr black hole. Bosonic conserved charges are related
to Killing vectors in a conventional way. Geometric interpretation of
supersymmetry charges remains a challenge.Comment: V2: 10 pages; discussion in sect. 4 and 5 extended, acknowledgements
and references adde
Punctate Inner Choroidopathy: A Systematic Review
This article reviews clinically relevant data regarding punctate inner choroidopathy, mainly the various treatment options. Punctate inner choroidopathy is an uncommon, inflammatory, multifocal chorioretinopathy affecting mostly young myopic women. It is characterized by the presence of multiple, small, well-defined, yellow-white fundus lesions, in the absence of intraocular inflammation. We describe etiology, clinical findings and ancillary tests that help in the diagnosis and detection of complications. Treatment options that have been used to manage patients with PIC and CNV include immunosuppressants, corticoids, laser photocoagulation, photodynamic therapy, intravitreal anti-VEGF agents and submacular surgery
Electric Field Effects on Graphene Materials
Understanding the effect of electric fields on the physical and chemical
properties of two-dimensional (2D) nanostructures is instrumental in the design
of novel electronic and optoelectronic devices. Several of those properties are
characterized in terms of the dielectric constant which play an important role
on capacitance, conductivity, screening, dielectric losses and refractive
index. Here we review our recent theoretical studies using density functional
calculations including van der Waals interactions on two types of layered
materials of similar two-dimensional molecular geometry but remarkably
different electronic structures, that is, graphene and molybdenum disulphide
(MoS). We focus on such two-dimensional crystals because of they
complementary physical and chemical properties, and the appealing interest to
incorporate them in the next generation of electronic and optoelectronic
devices. We predict that the effective dielectric constant () of
few-layer graphene and MoS is tunable by external electric fields (). We show that at low fields ( V/\AA)
assumes a nearly constant value 4 for both materials, but increases at
higher fields to values that depend on the layer thickness. The thicker the
structure the stronger is the modulation of with the electric
field. Increasing of the external field perpendicular to the layer surface
above a critical value can drive the systems to an unstable state where the
layers are weakly coupled and can be easily separated. The observed dependence
of on the external field is due to charge polarization driven by
the bias, which show several similar characteristics despite of the layer
considered.Comment: Invited book chapter on Exotic Properties of Carbon Nanomatter:
Advances in Physics and Chemistry, Springer Series on Carbon Materials.
Editors: Mihai V. Putz and Ottorino Ori (11 pages, 4 figures, 30 references
Sustainability Improvement of a composite materials’ industry through recycling and re-engineering process approaches
Recent Advances in Mechanics and Materials in DesignThis case study was aimed at measuring and assessing the potential improvements that could be made on the eco-efficiency performance of a composite materials’ industry, specifically a glass fibre reinforced plastic (GFRP) pultrusion manufacturing company. For this purpose, all the issues involved in the pultrusion process of GFRP profiles were analysed, the current ecoefficiency performance of the company was determined, all the procedures applied in the production process were revised, and improvement strategies were planned and investigated with basis on the performed analysis. The new eco-efficiency ratios were estimated taking into account the implementation of new proceedings and procedures through re-engineering the manufacturing process and recycling approaches. These features lead to significant improvements on the sequent assessed eco-efficiency ratios, yielding to a more sustainable product and manufacturing process of pultruded GFRP profiles
Punctate Inner Choroidopathy: A Systematic Review
This article reviews clinically relevant data regarding punctate inner choroidopathy, mainly the various treatment options. Punctate inner choroidopathy is an uncommon, inflammatory, multifocal chorioretinopathy affecting mostly young myopic women. It is characterized by the presence of multiple, small, well-defined, yellow-white fundus lesions, in the absence of intraocular inflammation. We describe etiology, clinical findings and ancillary tests that help in the diagnosis and detection of complications. Treatment options that have been used to manage patients with PIC and CNV include immunosuppressants, corticoids, laser photocoagulation, photodynamic therapy, intravitreal anti-VEGF agents and submacular surgery
Experimental study on polyester based concretes filled with glass fibre reinforced plastic recyclates – a contribution to composite materials sustainability
The development and applications of thermoset
polymeric composites, namely fibre reinforced plastics
(FRP), have shifted in the last decades more and more
into the mass market [1]. Despite of all advantages
associated to FRP based products, the increasing
production and consume also lead to an increasing
amount of FRP wastes, either end-of-lifecycle
products, or scrap and by-products generated by the
manufacturing process itself. Whereas thermoplastic
FRPs can be easily recycled, by remelting and
remoulding, recyclability of thermosetting FRPs
constitutes a more difficult task due to cross-linked
nature of resin matrix. To date, most of the thermoset
based FRP waste is being incinerated or landfilled,
leading to negative environmental impacts and
supplementary added costs to FRP producers and
suppliers. This actual framework is putting increasing
pressure on the industry to address the options
available for FRP waste management, being an
important driver for applied research undertaken cost
efficient recycling methods. [1-2]. In spite of this,
research on recycling solutions for thermoset
composites is still at an elementary stage. Thermal
and/or chemical recycling processes, with partial fibre
recovering, have been investigated mostly for carbon
fibre reinforced plastics (CFRP) due to inherent value
of carbon fibre reinforcement; whereas for glass fibre
reinforced plastics (GFRP), mechanical recycling, by
means of milling and grinding processes, has been
considered a more viable recycling method [1-2].
Though, at the moment, few solutions in the reuse of
mechanically-recycled GFRP composites into valueadded
products are being explored.
Aiming filling this gap, in this study, a new waste
management solution for thermoset GFRP based
products was assessed. The mechanical recycling
approach, with reduction of GFRP waste to powdered
and fibrous materials was applied, and the potential
added value of obtained recyclates was experimentally
investigated as raw material for polyester based
mortars. The use of a cementless concrete as host
material for GFRP recyclates, instead of a
conventional Portland cement based concrete, presents
an important asset in avoiding the eventual
incompatibility problems arisen from alkalis silica
reaction between glass fibres and cementious binder
matrix. Additionally, due to hermetic nature of resin
binder, polymer based concretes present greater ability
for incorporating recycled waste products [3].
Under this scope, different GFRP waste admixed
polymer mortar (PM) formulations were analyzed
varying the size grading and content of GFRP powder
and fibre mix waste. Added value of potential
recycling solution was assessed by means of flexural
and compressive loading capacities of modified
mortars with regard to waste-free polymer mortars
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