2,730 research outputs found
A short history of the first 3 years of the Community Genetics Network and its newsletter
When in 2007 it became clear that the Karger journal Community Genetics would change its name and scope, the first author started to establish an international, multidisciplinary e-mail network and a newsletter with papers authored by the members of the network. This paper reports on the first 3 years of the network. At the end of the 3-year period, there were 858 members, 50 newsletters had appeared, and almost 1,500 different papers from 458 journals had been cited. This model may serve as an example for others who want to bring together those sharing a common interest
Modeling the current distribution in HTS tapes with transport current and applied magnetic field
A numerical model is developed for the current distribution in a high temperature superconducting (HTS) tape, (Bi,Pb)2Sr2 Ca2Cu3Ox-Ag, subjected to a combination of a transport current and an applied magnetic field. This analysis is based on a two-dimensional formulation of Maxwell's equations in terms of an integral equation for the current density J. The finite thickness of the conductor and an arbitrary voltage-current relation (e.g. n-power relation, magnetic field dependency) for the conductor are included in the model. Another important feature is that the model also covers an applied magnetic field in arbitrary directions and a rotating field perpendicular to the conductor, which is of great interest for analyzing the AC loss of HTS (transformer) coils or three-phase electric power cables. A comparison is made with transport current loss measurements on an HTS tape with an AC applied fiel
Progress in the development of an 88-mm bore 10 Tn3Sn dipole magnet
A 10 T, 2-layer cos(&thetas;)-dipole model magnet with an 88 mm clear bore utilizing an advanced powder-in-tube Nb3Sn conductor is being developed for the LHC. A dedicated conductor development program has resulted in a well performing Rutherford cable containing strands that uniquely exhibit both an overall current density of 600 A/mm2 @ 11 T and filaments with a diameter of 20 ¿m. The resistance between crossing strands amounts to 30-70 ¿¿ by insertion of a stainless steel core. After being exposed to a transverse pressure of 200 MPa identical cables show negligible permanent degradation of the critical current. The mechanical support structure is further optimized in order to reduce the peak stress in the mid-plane to below 130 MPa at full excitation and to control the pre-stress build-up during system assembly. Prior to the manufacturing of the final coils a dummy 2-layer pole is wound, heat-treated at 675°C and vacuum resin impregnated. This paper presents the current status of the magnet development program and highlights in particular the successful conductor developmen
Modeling heat transfer from quench protection heaters to superconducting cables in Nb3Sn magnets
We use a recently developed quench protection heater modeling tool for an
analysis of heater delays in superconducting high-field Nb3Sn accelerator
magnets. The results suggest that the calculated delays are consistent with
experimental data, and show how the heater delay depends on the main heater
design parameters.Comment: 8 pages, Contribution to WAMSDO 2013: Workshop on Accelerator Magnet,
Superconductor, Design and Optimization; 15 - 16 Jan 2013, CERN, Geneva,
Switzerlan
Method and apparatus for detecting a fall by a user
According to an aspect, there is provided a fall detection apparatus for detecting a fall by a user, the fall detection apparatus comprising a processing unit configured to: receive measurements of movements of the user over time from a first movement sensor that is to be worn or carried by the user; determine if any of one or more objects are being carried or used by the user; and determine whether the user has fallen by processing the received measurements of the movements of the user and measurements of movements of any object that is being carried or used by the user
A general scaling relation for the critical current density in Nb3Sn
We review the scaling relations for the critical current density (Jc) in
Nb3Sn wires and include recent findings on the variation of the upper critical
field (Hc2) with temperature (T) and A15 composition. We highlight deficiencies
in the Summers/Ekin relations, which are not able to account for the correct
Jc(T) dependence. Available Jc(H) results indicate that the magnetic field
dependence for all wires can be described with Kramer's flux shear model, if
non-linearities in Kramer plots are attributed to A15 inhomogeneities. The
strain (eps) dependence is introduced through a temperature and strain
dependent Hc2*(T,eps) and Ginzburg- Landau parameter kappa1(T,eps) and a strain
dependent critical temperature Tc(eps). This is more consistent than the usual
Ekin unification, which uses two separate and different dependencies on Hc2*(T)
and Hc2*(eps). Using a correct temperature dependence and accounting for the
A15 inhomogeneities leads to a remarkable simple relation for Jc(H,T,eps).
Finally, a new relation for s(eps) is proposed, based on the first, second and
third strain invariants.Comment: Accepted Topical Review for Superconductor, Science and Technolog
Development of light and highly radiation transparent cryostats for FCC detector magnets:First analyses of insulation materials
For both versions of the Future Circular Collider, the electron-positron FCC ee, requiring a 2 T/4 m bore solenoid for particles spectrometry, and the hadron-hadron FCC hh, CERN is developing an innovative design for the detector solenoids, to enable their positioning inside the calorimeters directly surrounding the inner tracker. For this to happen, the cryostat design has to be optimized to achieve minimum radiation length. The novel design consists of a sandwich of thin inner and outer metallic shells for vacuum tightness, supported by an insulating material with sufficient mechanical resistance paired with lowest thermal conductivity, like Cryogel, a flexible aerogel structure (density 0.16 g/cm), or glass spheres (e.g. type K1 manufactured by 3M, with 65 μm diameter and density of 0.125 g/cm). These materials would allow constructing a 4 m bore, 6 m long cryostat with a 250 mm total thickness, a heat load less than 400 W on the cold mass and 10 kW on the thermal shield. In this paper, design options are discussed and methods for qualifying the materials presented
Optimization of the Kinematic Chain of the Thumb for a Hand Prosthesis Based on the Kapandji Opposition Test
Ponènica presentada a International Symposium on Computer Methods in Biomechanics and Biomedical Engineering - CMBBE 2019The thumb plays a key role in the performance of the hand for grasp-ing and manipulating objects. In artificial hands the complex thumb’s kinematic chain (TKC) is simplified and its five degrees of freedom are reduced to only one or two with the consequent loss of dexterity of the hand. The Kapandji op-position test (KOT) has been clinically used in pathological human hands for evaluating the thumb opposition and it has also been employed in some previ-ous studies as reference for the design of the TKC in artificial hands, but with-out a clearly stated methodology. Based on this approaches, in this study we present a computational method to optimize the whole TKC (base placement, link lengths and joint orientation angles) of an artificial hand based on its per-formance in the KOT. The cost function defined for the optimization (MPE) is a weighted mean position error when trying to reproduce the KOT postures and can be used also as a metric to quantify thumb opposition in the hand. As a case study, the method was applied to the improvement of the TKC of an artificial hand developed by the authors and the MPE was reduced to near one third of that of the original design, increasing significantly the number of reachable po-sitions in the KOT. The metric proposed based on the KOT can be used directly or in combination with other to improve the kinematic chain of artificial hands
Euro-Collins Solution Versus Uw-Solution for Long-Term Liver Preservation in the Isolated Rat-Liver Perfusion Model
To compare UW-solution (UW) and Euro-Collins (EC) for long-term liver preservation we investigated
the morphology and metabolic capacity of rat liver after 18 and 42-hours cold-storage in either UW or
EC
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