Investigation of a tagged computer architecture for the Prolog language

Call number: LD2668 .R4 EECE 1988 M44Master of ScienceComputing and Information Science

Tracer Tests in a Fractured Dolomite: 4. Double Porosity, Multiple-Rate Mass Transfer Processes in Two-Well Convergent Flow Tests

Two-well convergent-flow tracer tests conducted in the Culebra dolomite (Rustler Formation, New Mexico, USA) are analyzed with both single-and multiple-rate, double-porosity models. Parameter estimation is used to determine the mean and standard deviation of a Iog- normal distribution of diffision rate coefficients as well as the advective porosity and longitudinal dispersivity. At two different test sites, both mukirate and single-rate models are capable of accurately modeling the observed data. Estimated model parameters are tested against breakthrough curves obtained along the same transport pathway at a different pumping rate. Implications of the rnultirate mass-transfer model at time and length scales greater than those of the tracer tests include the instantaneous saturation of a fraction of the matrix ~d the possibility of a fraction of the matrix remaining unsaturated at long times

Expanding the role of impurity spectroscopy for investigating the physics of high-Z dissipative divertors

New techniques that attempt to more fully exploit spectroscopic diagnostics in the divertor and pedestal region during highly dissipative scenarios are demonstrated using experimental results from recent low-Z seeding experiments on Alcator C-Mod, JET and ASDEX Upgrade. To exhaust power at high parallel heat flux, q ‖ > 1 GW/m 2 , while minimizing erosion, reactors with solid, high-Z plasma facing components (PFCs) are expected to use extrinsic impurity seeding. Due to transport and atomic physics processes which impact impurity ionization balance, so-called ‘non-coronal’ effects, we do not accurately know and have yet to demonstrate the maximum q ‖ which can be mitigated in a tokamak. Radiation enhancement for nitrogen is shown to arise primarily from changes in Li- and Be-like charge states on open field lines, but also through transport-driven enhancement of H- and He-like charge states in the pedestal region. Measurements are presented from nitrogen seeded H-mode and L-mode plasmas where emission from N 1+ through N 6+ are observed. Active charge exchange spectroscopy of partially ionized low-Z impuri- ties in the plasma edge is explored to measure N 5+ and N 6+ within the confined plasma, while passive UV and visible spectroscopy is used to measure N 1+ -N 4+ in the boundary. Examples from recent JET and Alcator C-Mod experiments which employ nitrogen seeding highlight how improving spectroscopic cov- erage can be used to gain empirical insight and provide more data to validate boundary simulations.EURATOM 63305

Imaging Fourier transform spectrometers for environmental sensing

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77073/1/AIAA-1998-291-523.pd

Effect of toroidal field ripple on plasma rotation in JET

Dedicated experiments on TF ripple effects on the performance of tokamak plasmas have been carried out at JET. The TF ripple was found to have a profound effect on the plasma rotation. The central Mach number, M, defined as the ratio of the rotation velocity and the thermal velocity, was found to drop as a function of TF ripple amplitude (3) from an average value of M = 0.40-0.55 for operations at the standard JET ripple of 6 = 0.08% to M = 0.25-0.40 for 6 = 0.5% and M = 0.1-0.3 for delta = 1%. TF ripple effects should be considered when estimating the plasma rotation in ITER. With standard co-current injection of neutral beam injection (NBI), plasmas were found to rotate in the co-current direction. However, for higher TF ripple amplitudes (delta similar to 1%) an area of counter rotation developed at the edge of the plasma, while the core kept its co-rotation. The edge counter rotation was found to depend, besides on the TF ripple amplitude, on the edge temperature. The observed reduction of toroidal plasma rotation with increasing TF ripple could partly be explained by TF ripple induced losses of energetic ions, injected by NBI. However, the calculated torque due to these losses was insufficient to explain the observed counter rotation and its scaling with edge parameters. It is suggested that additional TF ripple induced losses of thermal ions contribute to this effect

Tracer Tests in a Fractured Dolomite: 3. Analysis of Mass Transfer in Single-Well Injection-Withdrawal Tests

We investigated multiple-rate diffusion as a possible explanation for observed behavior in a suite of single-well injection-withdrawal (SWIW) tests conducted in a fractured dolomite. We first investigated the ability of a conventional double-porosity model and a multirate diffusion model to explain the data. This revealed that the multirate diffusion hypothesis/model is most consistent with all available data, and is the only model to date that is capable of matching each of the recovery curves entirely. Second, we studied the sensitivity of the SWIW recovery curves to the distribution of diffusion rate coefficients and other parameters. We concluded that the SWIW test is very sensitive to the distribution of rate coefficients, but is relatively insensitive to other flow and transport parameters such as advective porosity and dispersivity. Third, we examined the significance of the constant double-log late-time slopes ({minus}2. 1 to {minus}2.8), which are present in several data sets. The observed late-time slopes are significantly different than would be predicted by either conventional double-porosity or single-porosity media, and are found to be a distinctive feature of multirate diffusion under SWIW test conditions. Fourth, we found that the estimated distributions of diffusion rate coefficients are very broad, with the distributions spanning a range of at least 3.6 to 5.7 orders of magnitude

Quality of Diabetes Care in U.S. Academic Medical Centers: Low rates of medical regimen change

To assess both standard and novel diabetes quality measures in a national sample of U.S. academic medical centers

Control System for the Holifield Radioactive Ion Beam Facility

A new accelerator control system is being impfemented as part of the development of the Holifield Radioactive Ion Beam Facility (HRIBF), a first generation radioactive ion beam (RIB) facility. The pre-existing accelerator control systems are based on 1970's technology and addition or alteration of controls is cumbersome and costly. A new, unified control system for the cyclotron and tandem accelerators. the RIB injector, ion sources, and accelerator beam lines is based on a commercial product from Vista Control Systems. Inc. Several other accelerator facilities. as well as numerous industrial sites, are now using this system. The control system is distributed over a number of computers which communicate over Ethernet and is easily extensible. Presently. implementation at the HRIBF is based on VAXNMS. VAX/ELN, VME, and Allen-Bradley PLCS programmable logic controller architectures. Expansion to include UMX platforms and CAMAC hardware support is planned. Operator interface is via X-terminals. The system has proven to be quite powerful, yet it has been easy to implement with a small staff. A Vista users group has resulted in shared software to implement specific controls. This paper details present system features and future implementations at the HRIBF