Construction experiences with SSC collider dipole magnets atFermilab

Full length and short model SSC (Superconducting Super Collider) 50 mm bore dipoles are being built and tested at Fermilab. The mechanical design of these magnets has been determined from experience with the construction of previous superconducting magnets. Construction experience includes coil fabrication, ground insulation, instrumentation, collaring, and yoke assembly. Fabrication techniques are explained, and construction problems and their solutions are reviewed. The relationship of short to long model construction is discussed     

Quench behavior of 1.5 m model SSC collider dipole magnets atFermilab

The quench behaviors of 10 model dipole magnets for the Superconducting Super Collider (SSC) have been studied. Horizontally split yoke, vertically split yoke, and the latest 50 mm diameter design were compared with regard to the quench characteristics. The excitation results showed a good progress of the R&D program. SSC magnets can now be built with no training to the required field of 6.65 T at 4.3 K     

Magnetic field measurements of 1.5 meter model SSC collider dipolemagnets at Fermilab

Magnetic field measurements have been performed at Fermilab on 1.5 m magnetic length model dipoles for the Superconducting Supercollider (SSC). Harmonic measurements are recorded at room temperature before and after the collared cell is assembled into the yoke and at liquid helium temperature. Measurements are made as a function of longitudinal position and excitation current. High field data are compared with room temperature measurements of both the collared coil and the completed yoked magnet and with the predicted fields of both the body of the magnet and the coil ends. The effects of yoking and cold testing agree well with predictions. One of the two cold-tested dipoles satisfies the SSC specification for sextupole/decapole     

Mechanical behavior of Fermilab-built 1.5 m model SSC colliderdipoles

Several model SSC (Superconducting Super Collider) dipole magnets (50-mm aperture, 1.5-m magnetic length) have been built and tested at Fermilab. These magnets are instrumented with strain gauges to measure stresses in the coil, the cold mass shell, and the coil end clamp assembly. Measurements are made of these quantities during assembly, cooldown, excitation, and warmup. The collar vertical deflection with prestress and the shell azimuthal tension agree quantitatively with design expectations. Coil prestresses within the desired range have been achieved without pole shims. Prestress loss with cooldown compares favorably with 40-mm models. Most of the axial I×B force is transmitted to the shell via collar-yoke-shell friction, and not by compressive loading of the coil end. The yoke parting plane gap remains closed to well above the operating point, and end clamp deflections are ≲0.05 mm under excitation     

Prediction of Chaotic Time-Series with a Resource-Allocating RBF Network

One of the main problems associated with artificial neural networks on-line learning methods is the estimation of model order. In this paper, we report about a new approach to constructing a resource-allocating radial basis function network exploiting weights adaptation using recursive least-squares technique based on Givens QR decomposition. Further, we study the performance of pruning strategy we introduced to obtain the same prediction accuracy of the network with lower model order. The proposed methods were tested on the task of Mackey-Glass time-series prediction. Order of resulting networks and their prediction performance were superior to those previously reported by Platt [12].     

Stability and oligosaccharide binding of the N1 cellulose-binding domain of Cellulomonas fimi endoglucanase CenC

Differential scanning calorimetry has been used to study the thermal stability and oligosaccharide-binding thermodynamics of the N-terminal cellulose-binding domain of Cellulomonas fimi beta-1,4-glucanase CenC (CBDN1). CBDN1 has a relatively low maximum stability (delta Gmax = 33 kJ/mol = 216 J/residue at 1 degree C and pH 6.1) compared to other small single-domain globular proteins. The unfolding is fully reversible between pH 5.5 and 9 and in accordance with the two-state equilibrium model between pH 5.5 and 11. When the single disulfide bond in CBDN1 is reduced, the protein remains unfolded at all conditions, as judged by NMR spectroscopy. This indicates that the intramolecular cross-link makes a major contribution to the stability of CBDN1. The measured heat capacity change of unfolding (delta Cp = 7.5 kJ mol-1 K-1) agrees well with that calculated from the predicted changes in the solvent accessible nonpolar and polar surface areas upon unfolding. Extrapolation of the specific enthalpy and entropy of unfolding to their respective convergence temperature indicates that per residue unfolding energies for CBDN1, an isolated domain, are in accordance with those found by Privalov (1) for many single-domain globular proteins. DSC thermograms of the unfolding of CBDN1 in the presence of various concentrations of cellopentaose were fit to a thermodynamic model describing the linkage between protein-ligand binding and protein unfolding. A global two-dimensional minimization routine is used to regress the binding enthalpy, binding constant, and unfolding thermodynamics for the CBDN1-cellopentaose system. Extrapolated binding constants are in quantitative agreement with those determined by isothermal titration calorimetry at 35 degrees C.