Directional isothermal growth of highly textured Bi2Sr2CaCu2Oy

For Bi2Sr2CaCu2Oy (2212), it is shown that an oxygen gradient, as opposed to a temperature gradient, can be used to produce large bulk forms of the 2212 superconductor with highly textured microstructures from an oxygen‐deficient melt held at a constant temperature. Material produced in this manner was found to have transition temperatures between 85 and 92 K, high critical current densities below 20 K, and modest critical current densities at 77 K

Processing and properties of hot-forged bulk superconductors

(Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} (Bi-2223) and TlBa{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} (Tl-1223) bars were hot forged in air at 820--850C. Final stresses of 2--3 MPa were sufficient to produce >95% dense Bi-2223 bars. In contrast, stresses to {approx}42 MPa were able to produce only 75--80% dense Tl-1223 bars. The Bi-2223 bars were more phase-pure and exhibited much stronger c-axis textures than the Tl-1223. Maximum critical current densities at 77 K were 8 {times} 10{sup 4} A/cm{sup 2} for the Bi-2223 and 2 {times} 10{sup 4}/cm{sup 2} for the Tl-1223. Fracture strength and toughness values were 140 MPa and 2.9 MPa{radical}m for the Bi-2223 and 50 MPa and 0.5 MPa{radical}m for the Tl-1223

Teaching Matters, Volume 2: Essays by the faculty and staff at the University of Maine at Farmington

Essays by the faculty and staff at the University of Maine at Farmington.https://scholarworks.umf.maine.edu/publications/1087/thumbnail.jp

Argonne National Laboratory Reports

The computer program PTA-1 performs pressure-transient analysis of large piping networks using the one-dimensional method of characteristics applied to a fluid-hammer formulation. The effect of elastic-plastic deformation of piping on pulse propagation is included in the computation. The program is particularly oriented toward the analysis of the effects of a sodium/water reaction on the intermediate heat-transport system of a liquid-metal-cooled fast breeder reactor, but may be applied just as usefully to other pulse sources and other piping systems. PTA-1 is capable of treating complex piping networks and includes a variety of junction types. Pipe friction and nonlinear velocity terms are included in the formulation. The program requires a minimum of input-data preparation and is designed to be easily used and modified. This report contains the governing equations, program structure, input requirements, program listing, and other information for PTA-1

Argonne National Laboratory Reports

PTAC was developed to predict pressure transients in nuclear-power-plant piping systems in which the possibility of cavitation must be considered. The program performs linear or nonlinear fluid-hammer calculations, using a fixed-grid method-of-characteristics solution procedure. In addition to pipe friction and elasticity, the program can treat a variety of flow components, pipe junctions, and boundary conditions, including arbitrary pressure sources and a sodium/water reaction. Essential features of transient cavitation are modeled by a modified column-separation technique. Comparisons of calculated results with available experimental data, for a simple piping arrangement, show good agreement and provide validation of the computational cavitation model. Calculations for a variety of piping networks, containing either liquid sodium or water, demonstrate the versatility of PTAC and clearly show that neglecting cavitation leads to erroneous predictions of pressure-time histories

Argonne National Laboratory Reports

The PTA-1 code for computing pressure transients in piping networks includes a computational model to treat the significant effect of plastic deformation of the piping on pulse propagation. Stanford Research Institute has completed an experimental program on the response of piping systems to internal pressure pulses which plastically deform portions of the piping. This report makes extensive comparisons between PTA-1 computations and these experimental results. The excellent agreement obtained for both pressure histories and strain histories for all the experiments indicates that the PTA-1 computational model for pipe plasticity effects is accurate. The computation-experiment comparisons also permit a number of observations and conclusions to be made on other aspects of computational modeling of pressure transients, particularly with respect to pulse propagation around elbows