AC Loss and Contact Resistance In Copper-Stabilized Nb3Al Rutherford Cables with and without a Stainless Steel Core

Calorimetric measurements of AC loss and hence interstrand contact resistance (ICR), were measured on three samples of Rutherford cable wound with Cu-stabilized jelly-roll type unplated Nb3Al strand. One of the cable types was furnished with a thin core of AISI 316L stainless steel and the other two were both uncored but insulated in different ways. The cables were subjected to a room-temperature-applied uniaxial pressure of 12 MPa that was maintained during the reaction heat treatment (RHT), then vacuum impregnated with CTD 101 epoxy, and repressurized to 100 MPa during AC-loss measurement. The measurements were performed at 4.2 K in a sinusoidal field of amplitude 400 mT at frequencies of 1 to 90 mHz (no DC-bias field) that was applied both perpendicular and parallel to the face of the cable (the face-on, FO, and edge-on, EO, directions, respectively). For the cored cable the FO-measured effective ICR (FO-ICR), was 5.27 . Those for the uncored cables were less than 0.08 . As shown previously for NbTi- and Nb3Sn-based Rutherford cables, the FO-ICR can be significantly increased by the insertion of a core, although in this case it is still below the range recommended for accelerator-magnet use. Post-measurement dissection of one of the cables showed that the impregnating resin had permeated between the strands and coated the core with a thin, insulating layer excepting for some sintered points of contact. In the uncored cables the strands were coated with resin except for the points of interstrand contact. It is suggested that in the latter case this tendency for partial coating leads to a processing-sensitive FO-ICR.Comment: Four pages, with two figure

Development of design allowable data for Celion 6000/LARC-160, graphite/polyimide composite laminates

A design allowables test program was conducted on Celion 6000/LARC-160 graphite polyimide composite to establish material performance over a 116 K (-250 F) to 589 K (600 F) temperature range. Tension, compression, in-plane shear and short beam shear properties were determined for uniaxial, quasi-isotropic and + or - 45 deg laminates. Effects of thermal aging and moisture saturation on mechanical properties were also evaluated. Celion 6000/LARC-160 graphite/polyimide can be considered an acceptable material system for structural applications to 589 K (600 F)

Assistance to the tourist industry

This study has been carried out as part of the government's continuing review of the economy, in particular the levels of assistance provided to various sectors, and examines the levels of assistance given to the tourism sector in New Zealand. The measurement of the effective rates of assistance (as distinct from effective rate of protection) is a relatively new concept but has recently become accepted as a comparative analysis tool. It allows different forms of assistance to be aggregated and for a comparison of the assistance to different sectors of the economy

Mechanical design of a high field common coil magnet

A common coil design for high field 2-in-1 accelerator magnets has been previously presented as a "conductor-friendly" option for high field magnets applicable for a Very Large Hadron Collider. This paper presents the mechanical design for a 14 tesla 2-in-1 dipole based on the common coil design approach. The magnet will use a high current density Nb/sub 3/Sn conductor. The design addresses mechanical issues particular to the common coil geometry: horizontal support against coil edges, vertical preload on coil faces, end loading and support, and coil stresses and strains. The magnet is the second in a series of racetrack coil magnets that will provide experimental verification of the common coil design approach. (9 refs)

Vitamin C Intravenous Treatment In the Setting of Atrial Fibrillation Ablation: Results From the Randomized, Double-Blinded, Placebo-Controlled CITRIS-AF Pilot Study

BackgroundCatheter ablation is an effective treatment for atrial fibrillation (AF), but high levels of post-procedure inflammation predict adverse clinical events. Ascorbic acid (AA) has shown promise in reducing inflammation but is untested in this population. We sought to test the feasibility, safety, and preliminary effects on inflammatory biomarkers in the CITRIS-AF (Vitamin C Intravenous Treatment In the Setting of Atrial Fibrillation Ablation) pilot study. Methods and ResultsPatients scheduled to undergo AF ablation (N=20) were randomized 1:1 to double-blinded treatment with AA (200 mg/kg divided over 24 hours) or placebo. C-reactive protein and interleukin-6 levels were obtained before the first infusion and repeated at 24 hours and 30 days. Pain levels within 24 hours and early recurrence of AF within 90 days were recorded. Median and interquartile range were aged 63 (56–70) years, 13 (65%) men, and 18 (90%) white. Baseline data were similar between the 2 groups except ejection fraction. Baseline C-reactive protein levels were 2.56 (1.47–5.87) mg/L and similar between groups (P=0.48). Change in C-reactive protein from baseline to 24 hours was +10.79 (+6.56–23.19) mg/L in the placebo group and +3.01 (+0.40–5.43) mg/L in the AA group (P=0.02). Conversely, change in interleukin-6 was numerically higher in the AA group, though not statistically significant (P=0.32). One patient in each arm developed pericarditis; no adverse events related to the infusions were seen. There were no significant differences between aggregated post-procedure pain levels within 24 hours or early recurrence of AF (both P\u3e0.05). ConclusionsHigh-dose AA is safe and well tolerated at the time of AF ablation and may be associated with a blunted rise in C-reactive protein, although consistent findings were not seen in interleukin-6 levels. Further studies are needed to validate these findings and explore the potential benefit in improving clinically relevant outcomes

The role of aerodynamic forces in a mathematical model for suspension bridges

In a fish-bone model for suspension bridges studied by us in a previous paper we introduce linear aerodynamic forces. We numerically analyze the role of these forces and we theoretically show that they do not influence the onset of torsional oscillations. This suggests a new explanation for the origin of instability in suspension bridges: it is a combined interaction between structural nonlinearity and aerodynamics and it follows a precise pattern. This gives an answer to a long-standing question about the origin of torsional instability in suspension bridges