Effects of Crust Ingestion on Mixer Pump Performance in Tank

In August 1999, a workshop was held at Pacific Northwest National Laboratory to discuss the effects of crust ingestion on mixer pump performance in Hanford Waste Tank 241-SY-101. The main purpose of the workshop was to evaluate the potential for crust ingestion to degrade mixing and/or damage the mixer pump. The need for a previously determined 12-inch separation between the top of the mixer pump inlet and the crust base was evaluated. Participants included a representative from the pump manufacturer, an internationally known expert in centrifugal pump theory, Hanford scientists and engineers, and operational specialists representing relevant fields of expertise. The workshop focused on developing an understanding of the pump design, addressing the physics of entrainment of solids and gases into the pump, and assessing the effects of solids and gases on pump performance. The major conclusions are summarized as follows: * Entrainment of a moderate amount of solids or gas from the crust should not damage the pump or reduce its lifetime, though mixing effectiveness will be somewhat reduced. * Air binding should not damage the pump. Vibration due to ingestion of gas, solids, and objects potentially could cause radial loads that might reduce the lifetime of bearings and seals. However, significant damage would require extreme conditions not associated with the small bubbles, fine solids, and chunks of relatively weak material typical of the crust. * The inlet duct extension opening, 235 inches from the tank bottom, should be considered the pump inlet, not the small gap at 262 inches. * A suction vortex exists at the inlet of all pumps. The characteristics of the inlet suction vortex in the mixer pump are very hard to predict, but its effects likely extend upward several feet. Because of this, the current 12-inch limit should be replaced with criteria based on actual monitored pump performance. The most obvious criterion (in addition to current operational constraints) is to monitor discharge pressure and cease pump operation if it falls below a predetermined amount. * There are no critically necessary tests to prove pump operability or performance before initiating the transfer and back-dilution sequence

TOPEX satellite concept. TOPEX option study report

Candidate bus equipment from the Viking, Applications Explorer Mission, and Small Scientific Satellite programs for application to the TOPEX mission options is assessed. Propulsion module equipment and subsystem candidates from the Applications Explorer Mission satellites and the Small Scientific Satellite spacecraft are evaluated for those TOPEX options. Several subsystem concepts appropriate to the TOPEX options are described. These descriptions consider performance characteristics of the subsystems. Cost and availability information on the candidate equipment and subsystems are also provided

Rapid identification and differentiation of the vaccine strain Rac H from EHV 1 field isolates using a non-radioactive DNA probe

A method for rapid differentiation between the EHV 1 live vaccine strain Rac H and field isolates is described. Total DNA was isolated from virus-infected small scale cell cultures. DNA fragments digested with restriction endonuclease BamHI were separated, transfered and immobilized on filter membranes. A Digoxigenin-labeled probe derived from EHV 1 was used for hybridization. This probe hybridized specifically to sequences of the inverted terminal repeat region which in case of Rac H include a deletion of 0.8 kb. By comparing the different migration patterns after blot hybridization it could be shown that in 65 isolates from cases of abortion the live vaccine strain Rac H was not involve

Dynamic response functions for the Holstein-Hubbard model

We present results on the dynamical correlation functions of the particle-hole symmetric Holstein-Hubbard model at zero temperature, calculated using the dynamical mean field theory which is solved by the numerical renormalization group method. We clarify the competing influences of the electron-electron and electron-phonon interactions particularity at the different metal to insulator transitions. The Coulomb repulsion is found to dominate the behaviour in large parts of the metallic regime. By suppressing charge fluctuations, it effectively decouples electrons from phonons. The phonon propagator shows a characteristic softening near the metal to bipolaronic transition but there is very little softening on the approach to the Mott transition.Comment: 13 pages, 19 figure

Observation of the Cosmic Ray Electron- Positron Ratio from 100 Mev to 3 Bev in 1964

Balloon flight data on cosmic ray electron- positron ratio from 100 MeV to 3 Be