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2-D and 3-D computations of curved accelerator magnets
In order to save computer memory, a long accelerator magnet may be computed by treating the long central region and the end regions separately. The dipole magnets for the injector synchrotron of the Advanced Photon Source (APS), now under construction at Argonne National Laboratory (ANL), employ magnet iron consisting of parallel laminations, stacked with a uniform radius of curvature of 33.379 m. Laplace's equation for the magnetic scalar potential has a different form for a straight magnet (x-y coordinates), a magnet with surfaces curved about a common center (r-{theta} coordinates), and a magnet with parallel laminations like the APS injector dipole. Yet pseudo 2-D computations for the three geometries give basically identical results, even for a much more strongly curved magnet. Hence 2-D (x-y) computations of the central region and 3-D computations of the end regions can be combined to determine the overall magnetic behavior of the magnets. 1 ref., 6 figs.
Date:
January 1, 1991
Creator:
Turner, L. R.
Object Type:
Article
System:
The UNT Digital Library
40- angstrom FEL designs for the PEP storage ring
We explore the use of the 2.2-km PEP storage ring at SLAC to drive a 40-{Angstrom} free-electron laser in the self-amplified spontaneous emission configuration. Various combinations for electron-beam and undulator parameters, as well as special undulator designs, are discussed. Saturation and high peak, in-band, coherent power (460 MW) are possible with a 67-m, hybrid permanent-magnet undulator in a ring bypass. A 100-m, cusp-field undulator can achieve high average, in-band, coherent power (0.25 W) in the main ring. The existing, 25.6-m, Paladin undulator at LLNL, with the addition of optical-klystron dispersive sections, is considered for both peak and average power. 35 refs., 4 figs., 1 tab.
Date:
January 1, 1991
Creator:
Fisher, A. S.; Gallardo, J. C. (Brookhaven National Lab., Upton, NY (United States)); Nuhn, H. D.; Tatchyn, R.; Winick, H. (Stanford Univ., CA (United States). Stanford Synchrotron Radiation Lab.) & Pellegrini, C. (California Univ., Los Angeles, CA (United States). Dept. of Physics)
Object Type:
Article
System:
The UNT Digital Library
180 MW demonstration of advanced tangentially-fired combustion techniques for the reduction of nitrogen oxide (NO sub x ) emissions from coal-fired boilers
ABB CE's Low NOx Bulk Furnace Staging (LNBFS) System and Low NOx Concentric Firing System (LNCFS) are demonstrated in stepwise fashion. These systems incorporate the concept of advanced overfire air (AOFA), clustered coal nozzles, and offset air. A complete description of the installed technologies is provided in the following section. The primary objective of the Plant Lansing Smith demonstration is to determine the long-term effects of commercially available tangentially-fired low NOx combustion technologies on NOx emissions and boiler performance. Short-term tests of each technology are also being performed to provide engineering information about emissions and performance trends. A target of achieving fifty percent NOx reduction using combustion modifications has been established for the project.
Date:
January 1, 1991
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
1989 Walker Branch Watershed Surveying and Mapping Including a Guide to Coordinate Transformation Procedures
Walker Branch Watershed is a forested, research watershed marked throughout by a 264 ft grid that was surveyed in 1967 using the Oak Ridge National Laboratory (X-10) coordinate system. The Tennessee Valley Authority (TVA) prepared a contour map of the watershed in 1987, and an ARC/INFO{trademark} version of the TVA topographic map with the X-10 grid superimposed has since been used as the primary geographic information system (GIS) data base for the watershed. However, because of inaccuracies observed in mapped locations of some grid markers and permanent research plots, portions of the watershed were resurveyed in 1989 and an extensive investigation of the coordinates used in creating both the TVA map and ARC/INFO data base and of coordinate transformation procedures currently in use on the Oak Ridge Reservation was conducted. They determined that the positional errors resulted from the field orientation of the blazed grid rather than problems in mapmaking. In resurveying the watershed, previously surveyed control points were located or noted as missing, and 25 new control points along the perimeter roads were surveyed. In addition, 67 of 156 grid line intersections (pegs) were physically located and their positions relative to mapped landmarks were recorded. As a result, coordinates …
Date:
January 1, 1991
Creator:
Timmins, S.
Object Type:
Report
System:
The UNT Digital Library
The 1990 Clean Air Act Amendments and the Great Lakes Economy: Challenges and Opportunities
This paper deals with the market for SO{sub 2} emission allowances over time and electric utility compliance choices. For currently high emitting plants ( > 2.5 lb SO{sub 2}/MMBtu), the 1990 Clean Air Act Amendments (CAAA) provide for about twice as many SO{sub 2} allowances to be issued per year in Phase 1 (1995--1999) than in Phase 2. Also, considering the scrubber incentives in Phase 1, there is likely to be substantial emission banking for use in Phase 2. Allowance prices are expected to increase over time at a rate less than the return on alternative investments, so utilities which are risk neutral or other potential speculators in the allowance market are not expected to bank allowances. The allowances will be banked by risk averse utilities or the utilities may buy forward contracts for SO{sub 2} allowances. However, speculators may play an important role by selling forward contracts for SO{sub 2} allowances to the risk averse utilities. The Argonne Utility Simulation Model (ARGUS) is being revised to incorporate the provisions of the CAAA acid rain title and to simulate SO{sub 2} allowance prices, compliance choices, capacity expansion, system dispatch, fuel use, and emissions. The revised model (ARGUS2) incorporates unit-level performance …
Date:
January 1, 1991
Creator:
Hanson, D.; Molburg, J.; Pandola, G.; Taxon, T.; Lurie, G.; Fisher, R. et al.
Object Type:
Article
System:
The UNT Digital Library
1991 Annual report on scientific programs: A broad research program on the sciences of complexity
1991 was continued rapid growth for the Santa Fe Institute (SFI) as it broadened its interdisciplinary research into the organization, evolution and operation of complex systems and sought deeply the principles underlying their dynamic behavior. Research on complex systems--the focus of work at SFI--involves an extraordinary range of topics normally studied in seemingly disparate fields. Natural systems displaying complex behavior range upwards from proteins and DNA through cells and evolutionary systems to human societies. Research models exhibiting complexity include nonlinear equations, spin glasses, cellular automata, genetic algorithms, classifier systems, and an array of other computational models. Some of the major questions facing complex systems researchers are: (1) explaining how complexity arises from the nonlinear interaction of simples components, (2) describing the mechanisms underlying high-level aggregate behavior of complex systems (such as the overt behavior of an organism, the flow of energy in an ecology, the GNP of an economy), and (3) creating a theoretical framework to enable predictions about the likely behavior of such systems in various conditions. The importance of understanding such systems in enormous: many of the most serious challenges facing humanity--e.g., environmental sustainability, economic stability, the control of disease--as well as many of the hardest scientific questions--e.g., …
Date:
January 1, 1991
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
A 1K Shadow RAM for circumvention applications
A 1K bit Shadow RAM has been developed for storage of critical data in a high transient radiation environment. The circuit includes a 1K bit (128 {times} 8) static RAM with two non-volatile (NV) shadows. The NV shadows are used to back-up the data in the static RAM allowing the circuit to be powered down during transient radiation without losing critical data. This paper will describe the circuit's operation and characterization results.
Date:
January 1, 1991
Creator:
Murray, J.R.
Object Type:
Article
System:
The UNT Digital Library
3d Image Reconstruction for PET by Multi-Slice Rebinning and Axial Filtering. [Positron Emission Tomography (Pet)]
Two different approaches are used at present to reconstruct from 3D coincidence data in PET. We refer to these approaches as the single-slice rebinning approach and the fully-3D approach. The single-slice rebinning approach involves geometrical approximations, but it requires the least possible amount of computation. Fully-3D reconstruction algorithms, both iterative and non-iterative, do not make such approximations, but require much more computation. Multi-slice rebinning with axial filtering is a new approach which attempts to achieve the geometrical accuracy of the fully-3D approach with the simplicity and modest amount of computation of the single-slice rebinning approach. The first step (multi-slice rebinning) involves rebinning of coincidence lines into a stack of 2D sinograms, where multiple sinograms are incremented for each oblique coincidence line. This operation is followed by an axial filtering operation, either before or after slice-by-slice reconstruction, to reduce the blurring in the axial direction. Tests with simulated and experimental data indicate that the new method has better geometrical accuracy than single-slice rebinning, at the cost of only a modest increase in computation. 11 refs.
Date:
January 1, 1991
Creator:
Lewitt, R. M.; Muehllehner, G. & Karp, J. S.
Object Type:
Article
System:
The UNT Digital Library
3D vadose zone modeling using geostatistical inferences
In developing a 3D model of the 600 ft thick interbedded basalt and sediment complex that constitutes the vadose zone at the Radioactive Waste Management Complex (RWMC) at the Idaho National Engineering Laboratory (INEL) geostatistical data were captured for 12--15 parameters (e.g. permeability, porosity, saturation, etc. and flow height, flow width, flow internal zonation, etc.). This two scale data set was generated from studies of subsurface core and geophysical log suites at RWMC and from surface outcrop exposures located at the Box Canyon of the Big Lost River and from Hell's Half Acre lava field all located in the general RWMC area. Based on these currently available data, it is possible to build a 3D stochastic model that utilizes: cumulative distribution functions obtained from the geostatistical data; backstripping and rebuilding of stratigraphic units; an expert'' system that incorporates rules based on expert geologic analysis and experimentally derived geostatistics for providing: (a) a structural and isopach map of each layer, (b) a realization of the flow geometry of each basalt flow unit, and (c) a realization of the internal flow parameters (eg permeability, porosity, and saturation) for each flow. 10 refs., 4 figs., 1 tab.
Date:
January 1, 1991
Creator:
Knutson, C.F. & Lee, C.B.
Object Type:
Article
System:
The UNT Digital Library
7th DOE workshop on computer-aided engineering
This report contains the abstracts and the program for the 7th DOE workshop on Computer-Aided Engineering. (LSP)
Date:
January 1, 1991
Creator:
unknown
Object Type:
Article
System:
The UNT Digital Library
7th international symposium on photosynthetic prokaryotes
This book contains the abstracts of all the presentations made either in oral or poster form, at the VII International Symposium on Photosynthetic Prokaryotes.
Date:
January 1, 1991
Creator:
Fuller, R.C.
Object Type:
Article
System:
The UNT Digital Library
The A.N.L Electrochemical Program for D.O.E. on Electric Vehicle R. & D.
This report summarizes the objectives, background, technical progress, and status of ANL electric vehicle battery R D tasks for DOE-EHP during the period of January 1 through March 31, 1991. The work is organized into the following six task areas: Project management; battery systems technology; lithium/sulfide batteries; advanced sodium/metal chloride battery; aqueous batteries; and EV Battery performance/life evaluation.
Date:
January 1, 1991
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Ab initio quantum chemistry in parallel-portable tools and applications
In common with many of the computational sciences, ab initio chemistry faces computational constraints to which a partial solution is offered by the prospect of highly parallel computers. Ab initio codes are large and complex (O(10{sup 5}) lines of FORTRAN), representing a significant investment of communal effort. The often conflicting requirements of portability and efficiency have been successfully resolved on vector computers by reliance on matrix oriented kernels. This proves inadequate even upon closely-coupled shared-memory parallel machines. We examine the algorithms employed during a typical sequence of calculations. Then we investigate how efficient portable parallel implementations may be derived, including the complex multi-reference singles and doubles configuration interaction algorithm. A portable toolkit, modeled after the Intel iPSC and the ANL-ACRF PARMACS, is developed, using shared memory and TCP/IP sockets. The toolkit is used as an initial platform for programs portable between LANS, Crays and true distributed-memory MIMD machines. Timings are presented. 53 refs., 4 tabs.
Date:
January 1, 1991
Creator:
Harrison, R.J.; Shepard, R. (Argonne National Lab., IL (United States)) & Kendall, R.A. (Battelle Pacific Northwest Lab., Richland, WA (United States))
Object Type:
Report
System:
The UNT Digital Library
Ablation of material by front surface spallation
Laser irradiation can be utilized to remove (i.e., ablate) material in a controlled manner by a hydrodynamic process, referred to as front surface spallation. In this process, a thin layer next to a free surface is heated to a level (below vaporization) so rapidly that it cannot undergo thermal expansion during laser heating. This generates a stress pulse, which propagates both inward and toward the free surface, with an initial amplitude that can be calculated using the Grueneisen coefficient. As the pulse reflects from the free surface, a tensile tail can develop of sufficient amplitude, exceeding the material strength, that a layer will be spalled off, taking much of the laser-deposited energy with it. To achieve spallation conditions, the laser wavelength, pulselength and fluence must be tailored to the absorption depth, Grueneisen coefficient, and spall strength. Hydrodynamic calculations and analytical modeling are presented to explain the process and illustrate conditions under which it should be expected to occur. Under some conditions, front surface spallation can have advantages over ablation by thermal vaporization, where residual temperatures are generally higher. 9 refs., 7 figs.
Date:
January 1, 1991
Creator:
Dingus, R. S. & Scammon, R. J.
Object Type:
Article
System:
The UNT Digital Library
Absence of antiferromagnetic order in UBe sub 13
The linear magnetostriction ({lambda}{sub //} and {lambda}{sub //}) of a single-crystalline sample of the heavy-fermion compound UBe{sub 13} has been measured for fields B < 8 T (B{sub //}(100)) in the temperature interval 0.3 < T < 12 K. We find neither evidence for the antiferromagnetic order (T{sub N}=8.8 K) nor for the magnetostrictive oscillations, that were reported recently. Instead {lambda} varies proportional to B{sup 2} as expected for a normal paramagnetic metal. 8 refs., 3 figs.
Date:
January 1, 1991
Creator:
de Visser, A.; van Dijk, N. H.; Franse, J. J. M.; Lacerda, A.; Flouquet, J.; Fisk, Z. et al.
Object Type:
Article
System:
The UNT Digital Library
Absence of molecular deuterium dissociation during room-temperature permeation into polystyrene ICF target shells
Polystyrene microshells filled with deuterium and tritium gas are important target shells for inertially confined fusion (ICF) and are particularly promising for target containing spin-polarized hydrogens fuels. A currently active approach to the latter uses polarized D in HD, in a method which requires preservation of the high purity of the initially prepared HD (very low specified H{sub 2} and D{sub 2} concentrations). This would not be possible if dissociation should occur during permeation into the target shells. We have thus tested polystyrene shells using a novel method which employs very pure polystyrene shells using a novel method which employs very pure ortho-D{sub 2} as the test gas. An upper limit of 6 {times} 10{sup {minus}4} was deduced for the dissociation of D{sub 2} upon room temperature permeation through an approximately 8 um wall of polystyrene, clearing the way for use of polystyrene target shells for ICF fusion experiments with spin-polarized hydrogens fuels. 19 refs., 1 fig.
Date:
January 1, 1991
Creator:
Honig, A.; Alexander, N.; Fan, Q.; Gram, R. & Kim, H.
Object Type:
Report
System:
The UNT Digital Library
Absorbing CAD system geometries into GEANT
The simulation community has for many years discussed the possibility of direct conversion of geometrical detector models from computer- aided design and engineering systems (CAD systems) to the simulation packages (which we shall assume means GEANT). This would allow fast and simultaneous optimization of the physics performance and structural integrity of detector designs. The benefit that this would offer is the avoidance of such problems as the late discovery of the rather thick cryostats in the D-Zero detector. Recent progress in the absorption of CAD geometries into GEANT models is reviewed, including descriptions of the additions to the I-DEAS solid modeller package developed for the EMPACT SSC proposal, the COGENT CAD-to-GEANT interpreter developed by Quantum Research Services, and the OCTAGON package for representing arbitrary shapes in GEANT. Likely future directions of development are described. 2 refs., 7 figs.
Date:
January 1, 1991
Creator:
Womersley, J.; Dragovitsch, P.; Youssef, S. (Florida State Univ., Tallahassee, FL (United States). Supercomputer Computations Research Inst.); Dunn, W.L.; Simpkins, J.D. & Yacout, A.M. (Quantum Research Services, Inc., Durham, NC (United States))
Object Type:
Article
System:
The UNT Digital Library
Absorption chillers: Part of the solution
Acid rain, ozone depletion, global warming, and implementation economics are considered as they relate to the advisability of expanding the application of absorption chillers. Introductory and background information are provided to put the discussion in the proper context. Then all four issues are discussed separately as they relate to absorption chillers. Acid rain and ozone depletion concerns, and implementation economics, are found to support the expanded use of absorption chillers. The global warming concern is found to be more of a gray area, but the areas of benefit correspond well with the conditions of greatest economic advantage. All things considered, absorption chillers are believed to be part of the environmental and economic solution. It is further believed that integrated resource planning (IRP) processes that consider electric and gas technologies on an equal footing would come to the same conclusion for many regions of the United States. 9 refs., 3 tabs.
Date:
January 1, 1991
Creator:
Occhionero, A.J. (American Gas Cooling Center, Arlington, VA (United States)); Hughes, P.J. (Oak Ridge National Lab., TN (United States)) & Reid, E.A. (Columbia Gas Distribution Co., Columbus, OH (United States))
Object Type:
Article
System:
The UNT Digital Library
Ac losses in YBa sub 2 Cu sub 3 O sub 7 and Bi sub 2 Sr sub 2 Ca sub 2 Ci sub 3 O sub 10 superconductors at power frequencies
Ac losses of sintered and melt-textured YBa{sub 2}Cu{sub 3}O{sub 7} bars and powder-in-a-tube processed Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10} tapes were measured at 4.2, 65, 70 and 77 K and at 15--180 Hz. In general, the results are well described by the critical state model for the ac losses. However, the losses for the Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10} tapes at 4.2 K exhibited significant contributions from the eddy currents in the Ag sheath.
Date:
January 1, 1991
Creator:
Orehotsky, J.; Reilly, K.M.; Suenaga, M. (Brookhaven National Lab., Upton, NY (United States)); Hikata, T.; Ueyama, M. & Sato, K. (Sumitomo Electric Industries Ltd., Osaka (Japan). Osaka Research Lab.)
Object Type:
Article
System:
The UNT Digital Library
Accelerating field step-up transformer in wake-field accelerators
In the wake-field scheme of particle acceleration, a short, intense drive bunch of electrons passes through a slow-wave structure, leaving behind high rf power in its wake field. The axial accelerating electric field associated with the rf can be quite large, > 100 MeV/m, and is used to accelerate a much less intense witness'' beam to eventual energies > 1 TeV. The rf power is deposited predominantly in the fundamental mode of the structure, which, for dielectric-lined waveguide as used at Argonne, is the TM{sub 01} mode. In all likelihood on the field amplitude will be limited only by rf breakdown of the dielectric material, the limit of which is currently unknown in the short time duration, high frequency regime of wake-field acceleration operation. To obtain such strong electric fields with given wake-field rf power, the dimensions of the dielectric-lined waveguide have to be fairly small, OD of the order of a cm and ID of a few mm, and this gives rise to the generation of strong deflection modes with beam misalignment. While a scheme exists to damp such deflection modes on a bunch-to-bunch time scale, head-tail beam deflection could still be a problem and BNS damping as well …
Date:
January 1, 1991
Creator:
Chojnacki, E.; Gai, W.; Schoessow, P. & Simpson, J.
Object Type:
Article
System:
The UNT Digital Library
Accelerator-driven neutron sources for fusion-materials testing
Several accelerator-driven neutron sources have been proposed for satisfying the requirements of a high-flux high-volume international fusion materials testing facility that could be built in the near future. This paper summarizes the features and projected performance for the three accelerator sources that are leading candidates for such a role and that are viewed by the International Energy Agency (IEA) as worthy of further evaluation. These are: (1) the d-Li source, in which 35-MeV deuteron beams are incident on flowing lithium targets, (2) the t-H{sub 2}O source, in which 21-MeV triton beams strike high-speed water jets, and (3) the Spallation source in which a 600-MeV proton beam bombards a heavy-metal target.
Date:
January 1, 1991
Creator:
Lawrence, G. P.
Object Type:
Article
System:
The UNT Digital Library
Accelerator-driven sub-critical target concept for transmutation of nuclear wastes
A means of transmuting key long-lived nuclear wastes, primarily the minor actinides (Np, Am, Cm) and iodine, using a hybrid proton accelerator and sub-critical lattice, is proposed. By partitioning the components of the light water reactor (LWR) spent fuel and by transmuting key elements, such as the plutonium, the minor actinides, and a few of the long-lived fission products, some of the most significant challenges in building a waste repository can be substantially reduced. The proposed machine, based on the described PHOENIX Concept, would transmute the minor actinides and the iodine produced by 75 LWRs, and would generate usable electricity (beyond that required to run the large accelerator) of 850 MW{sub e}. 19 refs., 20 figs.
Date:
January 1, 1991
Creator:
Van Tuyle, G. J.; Todosow, M.; Aronson, A. L.; Takahashi, H. (Brookhaven National Lab., Upton, NY (United States)) & Geiger, M. J. (Military Academy, West Point, NY (United States))
Object Type:
Article
System:
The UNT Digital Library
Accelerator technology for Los Alamos nuclear-waste-transmutation and energy-production concepts
Powerful proton linacs are being studied at Los Alamos as drivers for high-flux neutron sources that can transmute long-lived fission products and actinides in defense nuclear waste, and also as drivers of advanced fission-energy systems that could generate electric power with no long-term waste legacy. A transmuter fed by an 800-MeV, 140-mA cw conventional copper linac could destroy the accumulated {sup 99}Tc and {sup 129}I at the DOE's Hanford site within 30 years. A high-efficiency 1200-MeV, 140-mA niobium superconducting linac could drive an energy-producing system generating 1-GWe electric power. Preliminary design concepts for these different high-power linacs are discussed, along with the principal technical issues and the status of the technology base. 9 refs., 5 figs., 4 tabs.
Date:
January 1, 1991
Creator:
Lawrence, G. P.; Jameson, R. A. & Schriber, S. O.
Object Type:
Article
System:
The UNT Digital Library
Accelerator technology for the Los Alamos ATW (accelerator transmutation of nuclear waste) system
The Los Alamos concept for accelerator transmutation of nuclear waste (ATW) employs a high-power proton linear accelerator to generate intense fluxes of thermal neutrons (>10{sup 16} n/cm{sup 2}-s) through spallation on a lead-bismuth target. The nominal beam energy for an ATW accelerator is 1.6 GeV, with average current requirements ranging from 250 mA to 30 mA, depending on application specifics. A recent study of accelerator production of tritium (APT) led to the development of a detailed point design for a 1.6 GeV, 250 mA cw proton linac. The accelerator design was reviewed by the Energy Research Advisory Board (ERAB) and found to be technically sound. The Panel concluded that linac of this power level could now be implemented within the existing technology base, given an adequate component development program and an integrated engineering demonstration of the front end.
Date:
January 1, 1991
Creator:
Lawrence, G. P.
Object Type:
Article
System:
The UNT Digital Library