1,347 research outputs found
3-D Printed All-Dielectric GRIN Lens Antenna With an Integrated Feeder
In this paper we present the design, fabrication, and experimental verification of a new type of Graded-index (GRIN) lens antenna with an integrated feeder. The continuously varying refractive index distribution is chosen appropriately to offer the rays collimation at the lens aperture. It is practically implemented by varying the material density in a host medium, thus realizing a new type of all-dielectric high gain antenna, entirely using 3D printing. This solution can find application to high gain wireless communication and measurement systems. This GRIN lens antenna is printed in one monolithic process and does not require the feeder to be placed at a focal distance, thus complying with more strict space requirements. It accepts interchangeable feeds that can cover a wide frequency range. The directivity and gain are evaluated using near-field measurements in the Ku-band. A 40% measured aperture efficiency is achieved at 14GHz. The challenges and performance limitations that come with 3D printing, as compared to the design of idealized continuous distribution GRIN lenses are discussed
Evidences for Tsallis non-extensivity on CMR manganites
We found, from the analysis of vs. curves of some manganese oxides
(manganites), that these systems do not follow the traditional
Maxwell-Boltzmann statistics, but the Tsallis statistics, within the
\QTR{em}{normalized} formalism. Curves were calculated within the mean field
approximation, for various ferromagnetic samples and the results were compared
to measurements of our own and to various other authors published data, chosen
at random from the literature. The agreement between the experimental data and
calculated vs. curve, where is an effective
temperature, is excellent for all the compounds. The entropic parameter, ,
correlates in a simple way with the experimental value of , irrespect
the chemical composition of the compounds, heat treatment or other details on
sample preparation. Examples include (superextensivity),
(extensivity) and (subextensivity) cases.Comment: 12 pages, 3 figure
Dynamic Collection Scheduling Using Remote Asset Monitoring: Case Study in the UK Charity Sector
Remote sensing technology is now coming onto the market in the waste collection sector. This technology allows waste and recycling receptacles to report their fill levels at regular intervals. This reporting enables collection schedules to be optimized dynamically to meet true servicing needs in a better way and so reduce transport costs and ensure that visits to clients are made in a timely fashion. This paper describes a real-life logistics problem faced by a leading UK charity that services its textile and book donation banks and its high street stores by using a common fleet of vehicles with various carrying capacities. Use of a common fleet gives rise to a vehicle routing problem in which visits to stores are on fixed days of the week with time window constraints and visits to banks (fitted with remote fill-monitoring technology) are made in a timely fashion so that the banks do not become full before collection. A tabu search algorithm was developed to provide vehicle routes for the next day of operation on the basis of the maximization of profit. A longer look-ahead period was not considered because donation rates to banks are highly variable. The algorithm included parameters that specified the minimum fill level (e.g., 50%) required to allow a visit to a bank and a penalty function used to encourage visits to banks that are becoming full. The results showed that the algorithm significantly reduced visits to banks and increased profit by up to 2.4%, with the best performance obtained when the donation rates were more variable
Transport spin polarization of Ni_xFe_{1-x}: electronic kinematics and band structure
We present measurements of the transport spin polarization of Ni_xFe_{1-x}
(0<x<1) using the recently-developed Point Contact Andreev Reflection
technique, and compare them with our first principles calculations of the spin
polarization for this system. Surpisingly, the measured spin polarization is
almost composition-independent. The results clearly demonstrate that the sign
of the transport spin polarization does not coincide with that of the
difference of the densities of states at the Fermi level. Calculations indicate
that the independence of the spin polarization of the composition is due to
compensation of density of states and Fermi velocity in the s- and d- bands
Utilizing Co-Creative Principles to Develop an E-Learning Platform for Interprofessional Training on Tinnitus: The Erasmus+ Project Tin-TRAC
Tinnitus treatment, diagnosis and management across Europe varies significantly. The lack of national clinical guidelines for tinnitus management in most European countries and the absence of a common language across all disciplines involved is reflected in the diversification of healthcare practices. Interprofessional Training for Tinnitus Researchers and Clinicians (Tin-TRAC) is an Erasmus+ project that aims to develop common educational ground in the form of an e-Learning platform, co-created by patients, researchers and clinicians, which is able to unify tinnitus diagnosis and treatment strategies across Europe. A pan-European thematic educational platform integrating the best practices and latest research achievements with regard to tinnitus diagnosis and management has the potential to act as a facilitator of the reduction of interdisciplinary and interregional practice diversification. A detailed analysis of the educational needs of clinicians and researchers across disciplines will be followed by the co-creative development of the curriculum. Reusable learning objects will incorporate the training contents and will be integrated in an open e-Learning platform. Tin-TRAC envisions that its output will answer the need to create a common language across the clinicians and researchers of different disciplines that are involved in tinnitus management, and reduce patients’ prolonged suffering, non-adherence and endless referral trajectories
The Orbital Order Parameter in La0.95Sr0.05MnO3 probed by Electron Spin Resonance
The temperature dependence of the electron-spin resonance linewidth in
La0.95Sr0.05MnO3 has been determined and analyzed in the paramagnetic regime
across the orbital ordering transition. From the temperature dependence and the
anisotropy of linewidth and -value the orbital order can be unambiguously
determined via the mixing angle of the wave functions of the -doublet. The linewidth shows a similar evolution with temperature as
resonant x-ray scattering results
Functional Re-organization of Cortical Networks of Senior Citizens After a 24-Week Traditional Dance Program
Neuroscience is developing rapidly by providing a variety of modern tools for analyzing the functional interactions of the brain and detection of pathological deviations due to neurodegeneration. The present study argues that the induction of neuroplasticity of the mature human brain leads to the prevention of dementia. Promising solution seems to be the dance programs because they combine cognitive and physical activity in a pleasant way. So, we investigated whether the traditional Greek dances can improve the cognitive, physical and functional status of the elderly always aiming at promoting active and healthy aging. Forty-four participants were randomly assigned equally to the training group and an active control group. The duration of the program was 6 months. Also, the participants were evaluated for their physical status and through an electroencephalographic (EEG) examination at rest (eyes-closed condition). The EEG testing was performed 1–14 days before (pre) and after (post) the training. Cortical network analysis was applied by modeling the cortex through a generic anatomical model of 20,000 fixed dipoles. These were grouped into 512 cortical regions of interest (ROIs). High quality, artifact-free data resulting from an elaborate pre-processing pipeline were segmented into multiple, 30 s of continuous epochs. Then, functional connectivity among those ROIs was performed for each epoch through the relative wavelet entropy (RWE). Synchronization matrices were computed and then thresholded in order to provide binary, directed cortical networks of various density ranges. The results showed that the dance training improved optimal network performance as estimated by the small-world property. Further analysis demonstrated that there were also local network changes resulting in better information flow and functional re-organization of the network nodes. These results indicate the application of the dance training as a possible non-pharmacological intervention for promoting mental and physical well-being of senior citizens. Our results were also compared with a combination of computerized cognitive and physical training, which has already been demonstrated to induce neuroplasticity (LLM Care)
Effect of transport-induced charge inhomogeneity on point-contact Andreev reflection spectra at ferromagnet-superconductor interfaces
We investigate the transport properties of a ferromagnet-superconductor
interface within the framework of a modified three-dimensional
Blonder-Tinkham-Klapwijk formalism. In particular, we propose that charge
inhomogeneity forms via two unique transport mechanisms, namely, evanescent
Andreev reflection and evanescent quasiparticle transmission. Furthermore, we
take into account the influence of charge inhomogeneity on the interfacial
barrier potential and calculate the conductance as a function of bias voltage.
Point-contact Andreev reflection (PCAR) spectra often show dip structures,
large zero-bias conductance enhancement, and additional zero-bias conductance
peak. Our results indicate that transport-induced charge inhomogeneity could be
a source of all these anomalous characteristics of the PCAR spectra.Comment: 9 pages, 6 figure
A survey-based assessment of attitudes and needs regarding tinnitus healthcare among patients and healthcare professionals in Europe
Despite good agreement of national guidelines for the assessment and treatment of tinnitus, there is still substantial variation regarding tinnitus-related healthcare across Europe. In contrast to previous work, which has mainly focussed on the perspective of healthcare professionals, we here report the results of separate web-based surveys conducted with clinicians and researchers as well as tinnitus patients. These surveys were devised to obtain information about their respective attitudes and needs with respect to tinnitus healthcare, and to reveal possible interdisciplinary inconsistencies among clinicians and researchers. We mainly targeted participants from Germany, Cyprus, and Greece, the countries in which the institutions of the researchers involved in this project are based. Results showed, firstly, that the treatment satisfaction of the patients was overall more negative than that of the clinicians and researchers, and that the patients' treatment satisfaction did not depend on the number of different treatments they had received. Secondly, patients as well as clinicians and researchers indicated that they were interested in learning more about a variety of tinnitus-related topics, especially treatment strategies, with no marked differences between clinicians from different professional disciplines. This suggests similar tinnitus-specific educational needs in patients and healthcare professionals
Varieties of developmental dyslexia in Greek children
The current study aimed to investigate in a group of nine Greek children with dyslexia (mean age 9.9 years) whether the surface and phonological dyslexia subtypes could be identified. A simple regression was conducted using printed word naming latencies and nonword reading accuracy for 33 typically developing readers. Ninety per cent confidence intervals were established and dyslexic children with datapoints lying outside the confidence intervals were identified. Using this regression-based method three children with the characteristic of phonological dyslexia (poor nonword reading), two with surface dyslexia (slow word naming latencies) and four with a mixed profile (poor nonword reading accuracy and slow word naming latencies) were identified. The children were also assessed in spelling to dictation, phonological ability, rapid naming, visual memory and multi-character processing (letter report). Results revealed that the phonological dyslexia subtype children had difficulties in tasks of phonological ability, and the surface subtype children had difficulties in tasks of multi-character simultaneous processing ability. Dyslexic children with a mixed profile showed deficits in both phonological abilities and multi-character processing. In addition, one child with a mixed profile showed a rapid naming deficit and another showed a difficulty in visual memory for abstract designs. Overall the results confirm that the surface and phonological subtypes of developmental dyslexia can be found in Greek-speaking children. They also indicate that different subtypes are associated with different underlying disorders
- …