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3-D Field Computations for Accelerator Magnets Using Finite Element and Integral Codes: Two dimensional (2-D) computation has been an accepted part of the design of accelerator magnets since the 1960's, but three-dimensional (3-D) computations are still not fully trusted. This paper describes the successes and limitations of 3-D computations, as applied to accelerator magnets for the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). Both the finite element code TOSCA and the edge element volume integral code CORAL have been used in these computations. The ends of the dipole bending magnet for the injector synchrotron were designed using TOSCA; comparisons with measurements are described. Computation of other APS magnets are also described.
3-D numerical investigation of the mantle dynamics associated with the breakup of Pangea: Three-dimensional finite element calculations in spherical geometry are performed to study the response of the mantle with platelike blocks at its surface to an initial condition corresponding to subduction along the margins of Pangea. The mantle is treated as an infinite Prandtl number Boussinesq fluid inside a spherical shell with isothermal, undeformable, free-slip boundaries. Nonsubducting rigid blocks to model continental lithosphere are included in the topmost layer of the computational mesh. At the beginning of the numerical experiments these blocks represent the present continents mapped to their approximate Pangean positions. Asymmetrical downwelling at the margins of these nonsubducting blocks results in a pattern of stresses that acts to pull the supercontinent apart. The calculations suggest that the breakup of Pangea and the subsequent global pattern of seafloor spreading was driven largely by the subduction at the Pangean margins.
101-SY Hydrogen Safety Project chemical analysis support: Window ``C`` total organic carbon analysis: Core samples taken from Hanford double-shell waste tank 101-SY during Window ``C`` (after the May 1991 gas release event) were analyzed for total organic carbon by the staff of the Analytical Chemistry Laboratory at Pacific Northwest Laboratory. The procedure uses the oxidation/extraction method of hot acid persulfate oxidation. Evolved CO{sub 2} is measured by a UIC Coulometric Carbon Analyzer coulometry detector. Samples are acidified with heated sulfuric acid to drive off all inorganic carbonate carbon as CO{sub 2}. Excess potassium persulfate oxidant, along with a silver catalyst, is then added to the heated sulfuric acid solution. All organic carbon is oxidized to CO{sub 2}, swept away by the carrier gas to the Coulometrics Analyzer, and the results calculated and displayed directly as {mu}g carbon titrated.
101-SY Hydrogen Safety Project chemical analysis support: Window C'' total organic carbon analysis: Core samples taken from Hanford double-shell waste tank 101-SY during Window C'' (after the May 1991 gas release event) were analyzed for total organic carbon by the staff of the Analytical Chemistry Laboratory at Pacific Northwest Laboratory. The procedure uses the oxidation/extraction method of hot acid persulfate oxidation. Evolved CO{sub 2} is measured by a UIC Coulometric Carbon Analyzer coulometry detector. Samples are acidified with heated sulfuric acid to drive off all inorganic carbonate carbon as CO{sub 2}. Excess potassium persulfate oxidant, along with a silver catalyst, is then added to the heated sulfuric acid solution. All organic carbon is oxidized to CO{sub 2}, swept away by the carrier gas to the Coulometrics Analyzer, and the results calculated and displayed directly as {mu}g carbon titrated.
500 MW demonstration of advanced wall-fired combustion techniques for the reduction of nitrogen oxide (NO[sub x]) emissions from coal-fired boilers: The project provides a stepwise retrofit of an advanced overfire air (AOFA) system followed by low NO[sub x] burners (LNB). During each test phase of the project, diagnostic, performance, long-term, and verification testing will be performed. These tests are used to quantify the NO[sub x] reductions of each technology and evaluate the effects of those reductions on other combustion parameters such as particulatecharacteristics and boiler efficiency. Baseline, AOFA, and LNB without AOFA test segments have been completed. Analysis of the 94 days of LNB long-term data collected show the full-load NO[sub x] emission levels to be approximately 0.65 lb/MBtu. Flyash LOI values for the LNB configuration are approximately 8 percent at full-load. Corresponding values for the AOFA configuration are 0.94 lb/MBtu and approximately 10 percent. Abbreviated diagnostic tests for the LNB+AOFA configuration indicate that at 500 MWe, NO[sub x] emissions are approximately 0.55 lb/MBtu with corresponding flyash LOI values of approximately 11 percent. For comparison, the long-term full-load, baseline NO[sub x] emission level was approximately 1.24 lb/MBtu at 5.2 percent LOI. Comprehensive testing of the LNB+AOFA configuration will be performed when the stackparticulate emissions issue is resolved. Testing of a process optimization package on Plant Hammond Unit 4 was performed during this quarter. The software was configured to minimize NO[sub x] emissions using total combustion air flow and advanced overfire air distribution as the controlled parameters. Preliminary results from this testing indicate that this package shows promise in reducing NO[sub x] emissions while maintaining or improving other boiler performance parameters.
The 1991 natural gas vehicle challenge: Developing dedicated natural gas vehicle technology: An engineering research and design competition to develop and demonstrate dedicated natural gas-powered light-duty trucks, the Natural Gas Vehicle (NGV) Challenge, was held June 6--11, 1191, in Oklahoma. Sponsored by the US Department of Energy (DOE), Energy, Mines, and Resources -- Canada (EMR), the Society of Automative Engineers (SAE), and General Motors Corporation (GM), the competition consisted of rigorous vehicle testing of exhaust emissions, fuel economy, performance parameters, and vehicle design. Using Sierra 2500 pickup trucks donated by GM, 24 teams of college and university engineers from the US and Canada participated in the event. A gasoline-powered control testing as a reference vehicle. This paper discusses the results of the event, summarizes the technologies employed, and makes observations on the state of natural gas vehicle technology.
1992 Columbia River Salmon Flow Measures Options Analysis/EIS.: This Options Analysis/Environmental Impact Statement (OA/EIS) identifies, presents effects of, and evaluates the potential options for changing instream flow levels in efforts to increase salmon populations in the lower Columbia and Snake rivers. The potential actions would be implemented during 1992 to benefit juvenile and adult salmon during migration through eight run-of-river reservoirs. The Corps of Engineers (Corps) prepared this document in cooperation with the Bonneville Power Administration and the Bureau of Reclamation. The US Fish and Wildlife Service (FSWS) is a participating agency. The text and appendices of the document describe the characteristics of 10 Federal projects and one private water development project in the Columbia River drainage basin. Present and potential operation of these projects and their effects on the salmon that spawn and rear in the Columbia and Snake River System are presented. The life history, status, and response of Pacific salmon to current environmental conditions are described.
1992 Columbia River Salmon Flow Measures Options Analysis/EIS : Appendices.: This Options Analysis/Environmental Impact Statement (OA/EIS) identifies, presents effects of, and evaluates the potential options for changing instream flow levels in efforts to increase salmon populations in the lower Columbia and Snake rivers. The potential actions would be implemented during 1992 to benefit juvenile and adult salmon during migration through eight run-of-river reservoirs. The Corps of Engineers (Corps) prepared this document in cooperation with the Bonneville Power Administration and the Bureau of Reclamation. The US Fish and Wildlife Service (FWS) is a participating agency. The text and appendices of the document describe the characteristics of 10 Federal projects and one private water development project in the Columbia River drainage basin. Present and potential operation of these projects and their effects on the salmon that spawn and rear in the Columbia and Snake River System are presented. The life history, status, and response of Pacific salmon to current environmental conditions are described. The document concludes with an evaluation of the potential effects that could result from implementing proposed actions. The conclusions are based on evaluation of existing data, utilization of numerical models, and application of logical inference. This volume contains the appendices.
33rd Annual Report: The ACIR Library is composed of publications that study the interactions between different levels of government. This document is an annual report.
Absorption of undulator radiation in media: Detailed thermal stress analyses of beamline and optical components subject to high heat loads require an Accurate determination of the absorbed power profile for accurate prediction of the temperature profile and structural parameters. This is particularly important for high power beams from wigglers and undulators at the third generation synchrotron sources because components must, in general, be designed and maintained with strict mechanical tolerances. The spatial distribution of the power density of an undulator is a rapidly varying function of the energy of the photons suggesting that approximative methods based on a smooth spectral variation may not be valid. In this paper, a fast code for calculating undulator spectra is developed and compared with a wiggler code for approximation of the same spectra. Results from numerical simulations, including the emittance of the stored particle beam, are presented for the absorbed power density in a beryllium window. We find markedly different results for the two models for far off-axis radiation indicating the inadequacy of the wiggler model applied to an undulator spectrum in this case. The wiggler model overestimates the total absorbed power by as much as 82% for the beryllium window.
Accelerated glass reaction under PCT conditions: Static leach tests similar to PCT (Product Consistency Test) were performed for up to 2 years to assess long-term reaction behavior of high-level nuclear waste glasses similar to those at Defense Waste Processing Facility. These tests show the reaction rate to decrease with the reaction time from an initially high rate to a low rate, but then to accelerate to a higher rate after reaction times of about 1 year, depending on glass surface area/leachant volume ratio used. Solution concentrations of soluble glass components increase as the reaction is accelerated, while release of other glass components into solution is controlled by secondary phases. Net result is that transformation of glass to stable phases is accelerated while the solution becomes enriched in soluble components not effectively contained in secondary phases. Rate becomes linear in time after the acceleration and may be similar to the initial forward rate. A current model of glass reaction predicts that the glass reaction will be accelerated upon the formation of secondary phases which lower the silicic acid solution concentration. These tests show total Si concentration to increase upon reaction acceleration, however, which may be due to the slightly higher pH attained with the acceleration. The sudden change in the reaction rate is likely due to secondary phase formation. 17 refs, 2 tabs, 3 figs.
Accelerator research studies: The Accelerator Research Studies program at the University of Maryland, sponsored by the Department of Energy under grant number DE-FG05-91ER40642, is currently in the first year of a three-year funding cycle. The program consists of the following three tasks: TASK A, Study of Transport and Longitudinal Compression of Intense, High-Brightness Beams, TASK B, Study of Collective Ion Acceleration by Intense Electron Beams and Pseudospark Produced High Brightness Electron Beams; TASK C, Study of a Gyroklystron High-power Microwave Source for Linear Colliders. In this report we document the progress that has been made during the past year for each of the three tasks.
Accelerator simulation using computers: Every accelerator or storage ring system consists of a charged particle beam propagating through a beam line. Although a number of computer programs exits that simulate the propagation of a beam in a given beam line, only a few provide the capabilities for designing, commissioning and operating the beam line. This paper shows how a multi-track'' simulation and analysis code can be used for these applications.
Accelerator simulation using computers: Every accelerator or storage ring system consists of a charged particle beam propagating through a beam line. Although a number of computer programs exits that simulate the propagation of a beam in a given beam line, only a few provide the capabilities for designing, commissioning and operating the beam line. This paper shows how a ``multi-track`` simulation and analysis code can be used for these applications.
Accelerator transmutation of sup 129 I: Iodine-129 is one of several long-lived reactor products that is being considered for transmutation by the Los Alamos Accelerator Transmutation of Waste (ATW) program. A reasonable rate of transmutation of 1291 is possible in this system because of the anticipated high neutron flux generated from the accelerator. This report summarizes previous papers dealing with the transmutation of 1291 where reactor technologies have been employed for neutron sources. The transmutation process is considered marginal under these conditions. Presented here are additional information concerning the final products that could be formed from the transmutation process in the ATW blanket. The transmutation scheme proposes the use of solid iodine as the target material and the escape of product xenon from the containers after van Dincklange (1981). Additional developmental plans are considered.
Accident information needs: A Five-step methodology has been developed to evaluate information needs for nuclear power plants under accident conditions and the availability of plant instrumentation during severe accidents. Step 1 examines the credible accidents and their relationships to plant safety functions. Step 2 determines the information personnel involved in accident management will need to understand plant behavior. Step 3 determines the capability of the instrumentation to function properly under severe accident conditions. Step 4 determines the conditions expected during the identified severe accidents. Step 5 compares the instrument capabilities and the severe accident conditions to evaluate the availability of the instrumentation to supply needed plant information.
Accounting for the effect of TDS and NCG on Salton Sea reservoir response: The Salton Sea reservoir, located in Imperial County, Ca., is unique in several ways from most liquid-dominated geothermal reservoirs that have been developed to date. One of these differences is the presence of hyper-saline brines containing up to 28% TDS (Total Dissolved Solids) and up to 0.2% NCG (Non-Condensible Gas). A simple material and energy balance model has been developed to study the effect of TDS and NCG on Salton Sea reservoir response. This study demonstrated that during the development of a two-phase system the partitioning of the NCG into the vapor phase and the consequential concentration of the TDS in the brine drastically alters the reservoir fluid properties. In modeling pressure depletion of hyper-saline reservoirs, such as the Salton Sea, these changes in reservoir fluid composition were shown to seriously affect the simulation results. As a result of these findings, a compositional fluid property package was developed using published data on H{sub 2}O-CO{sub 2}-NaCl mixtures. This fluid property package was then incorporated into the simulation program used by Unocal. Validation of the fluid property package in this simulation program was made using measured reservoir temperature, surface enthalpy, and surface flash data. The development of a compositional simulation program for geothermal applications has advanced our ability to study depletion mechanisms that are sensitive to compositional changes. This program is currently being used to study the effect of injection and steam cap development on long term operations and to develop a field model of the Salton Sea reservoir.
Accrediting industrial safety training programs: There are job-specific training requirements established by regulations that Impose stringent training requirements on a contractor, for example, the Occupational Safety Health Act (OSHA). Failure to comply with OSHA training requirements can result in severe penalties being levied against a company. Although an accredited training program is expensive, it is a possible solution for minimizing risks associated with job-specific training requirements for employees. Operating DOE contractors direct approximately 10 percent of the operating funds toward training activities. Training needs for contractors span a broad range, from requirements awareness training for managers, to general training required on a one-time basis for all employees, to highly specialized training programs for employees involved In clean-up operations at hazardous waste sites. With this kind of an investment in training, it is logical to maximize the most return on an investment of training funds and to limit exposure to liability suits whenever possible. This presentation will provide an overview of accredited industrial safety programs. The criteria for accredited industrial safety programs will be defined. The question of whether accredited training programs are necessary will be examined. Finally, advantages and disadvantages will be identified for accrediting industrial safety training programs.
An accurate formulation of the solubility of CO₂ in water, for geothermal applications: The solubility correlations for the H{sub 2}O-CO{sub 2} system applied so far for numerical simulation of geothermal reservoir and well flows are crude. This is due, at least partly, to the significant disagreement existing between the solubility models and results published in the specialized literature. In this work we analyze the reasons underlying this disagreement. On this basis, we propose a thermodynamically correct, and numerically accurate model for the solubility of carbon dioxide in water. Its range of validity is up to 350 C and 500 bar. Our main contributions are: (a) the adoption of an equation of state for the gas phase that realistically accounts for the non-ideal behavior of both components and that of the mixture, within the P-T range considered; and (b) to accurately include the effects of temperature and pressure on the solubility of carbon dioxide in the liquid phase. The proposed model fits the available phase equilibrium data for the H{sub 2}O-CO{sub 2} system nicely. In particular, it does not present the severe conflict between the linearity of the model and the lack of linearity of the data, evident in earlier models. The tight fit obtained with our model indicates that the complexities of H{sub 2}-CO{sub 2} phase equilibrium are well represented by it.
Accurate plutonium waste measurements using the sup 252 Cf add-a- source technique for matrix corrections: We have developed a new measurement technique to improve the accuracy and sensitivity of the nondestructive assay (NDA) of plutonium scrap and waste. The 200-{ell} drum assay system uses the classical NDA method of counting passive-neutron coincidences from plutonium but has added the new features of add-a-source'' to improve the accuracy for matrix corrections and statistical techniques to improve the low-level detectability limits. The add-a-source technique introduces a small source of {sup 252}Cf (10{sup {minus}8} g) near the external surface of the sample drum. The drum perturbs the rate at which coincident neutrons from the {sup 252}Cf are counted. The perturbation provides the data to correct for the matrix and plutonium inside the drum. The errors introduced from matrix materials in 200-{ell} drums have been reduced by an order of magnitude using the add-a-source technique. In addition, the add-a-source method can detect unexpected neutron-shielding material inside the drum that might hide the presence of special nuclear materials. The detectability limit of the new waste-drum assay system for plutonium is better than prior systems for actual waste materials. For the in-plant installation at a mixed-oxide fabrication facility, the detectability limit is 0.73 mg of {sup 24O}Pu (or 2.3 mg of high-burnup plutonium) for a 15-min. measurement. For a drum containing 100 kg of waste, this translates to about 7 nCi/g. This excellent sensitivity was achieved using a special low-background detector design, good overhead shielding, and statistical techniques in the software to selectively reduce the cosmic-ray neutron background.
An accurate PVT model for geothermal fluids as represented by H{sub 2}O-CO{sub 2}-NaCl mixtures: Estimates for the pressure decline in high TDS geothermal fluids containing dissolved gases are extremely sensitive to the PVT representation of the reservoir fluid. Significant errors in predicted pressures will occur if the geothermal fluid is represented by one or two pseudo components with modified water properties. As a result, we have developed a PVT model to predict the thermodynamic properties of a prototype geothermal fluid as represented by three-component H{sub 2}O-CO{sub 2}-NaCl mixtures. The range of applicability of the model is: Temperatures from 75 to 700+ F, pressures from 14.7 to 5000 psi, carbon dioxide content from 0-5 wt%, and salt concentrations to 30 wt%. The model has been implemented into Unocal's version of a commercially available reservoir simulator and is currently being used to study one of Unocal's high salinity reservoirs located in the Imperial Valley of California.
The ACPMAPS system: A detailed overview: This paper describes the ACPMAPS computing system -- its purpose, its hardware architecture, how the system is used, and relevant programming paradigms and concepts. Features of the hardware and software will be discussed in some detail, both quantitative and qualitative. This should give some perspective as to the suitability of the ACPMAPS system for various classes of applications, and as to where this system stands in the spectrum of today's supercomputers. The ACPMAPS project at Fermilab was initiated in 1987 as a collaborations between the Advanced Computer Program (now the Computer R D department) and the lattice gauge physicists in the Theory department. ACPMAPS is an acronym for Advanced Computer Program Multiple Array Processor System -- this acronym is no longer accurate, but the name has stuck. Although research physics computations were done on ACPMAPS as early as 1989, the full-scale system was commissioned as a reliable physics tool in early 1991. The original ACPMAPS was a 5 Gflop (peak) system. An upgrade by a factor of ten in computer power and memory size, but substituting a new CPU board, will occur during early 1991 -- this is referred to as the new ACPMAPS Upgrade or 50 GF ACPMAPS. The appellation ACPMAPS II has also been applied to the upgrade; this is somewhat of a misnomer, since only one of five major components was changed.
Activated transport in AMTEC electrodes: Transport of alkali metal atoms through porous cathodes of alkali metal thermal-to-electric converter (AMTEC) cells is responsible for significant, reducible losses in the electrical performance of these cells. Experimental evidence for activated transport of metal atoms at grain surfaces and boundaries within some AMTEC electrodes has been derived from temperature dependent studies as well as from analysis of the detailed frequency dependence of ac impedance results for other electrodes, including thin, mature molybdenum electrodes which exhibit transport dominated by free molecular flow of sodium gas at low frequencies or dc conditions. Activated surface transport will almost always exist in parallel with free molecular flow transport, and the process of alkali atom adsorption/desorption from the electrode surface will invariably be part of the transport process, and possibly a dominant part in some cases. Little can be learned about the detailed mass transport process from the ac impedance or current voltage curves of an electrode at one set of operating parameters, because the transport process includes a number of important physical parameters that are not all uniquely determined by one experiment. The temperature dependence of diffusion coefficient of the alkali metal through the electrode in several cases provides an activation energy and pre-exponential, but at least two activated processes may be operative, and the activation parameters should be expected to depend on the alkali metal activity gradient that the electrode experiences. In the case of Pt/W/Mn electrodes operated for 2500 hours, limiting currents varied with electrode thickness, and the activation parameters could be assigned primarily to the surface/grain boundary diffusion process. 17 refs.
An adaptive algorithm for modifying hyperellipsoidal decision surfaces: The LVQ algorithm is a common method which allows a set of reference vectors for a distance classifier to adapt to a given training set. We have developed a similar learning algorithm, LVQ-MM, which manipulates hyperellipsoidal cluster boundaries as opposed to reference vectors. Regions of the input feature space are first enclosed by ellipsoidal decision boundaries, and then these boundaries are iteratively modified to reduce classification error. Results obtained by classifying the Iris data set are provided.
An adaptive crystal bender for high power synchrotron radiation beams: Perfect crystal monochromators cannot diffract x-rays efficiently, nor transmit the high source brightness available at synchrotron radiation facilities, unless surface strains within the beam footprint are maintained within a few arcseconds. Insertion devices at existing synchrotron sources already produce x-ray power density levels that can induce surface slope errors of several arcseconds on silicon monochromator crystals at room temperature, no matter how well the crystal is cooled. The power density levels that will be produced by insertion devices at the third-generation sources will be as much as a factor of 100 higher still. One method of restoring ideal x-ray diffraction behavior, while coping with high power levels, involves adaptive compensation of the induced thermal strain field. The design and performance, using the X25 hybrid wiggler beam line at the National Synchrotron Light Source (NSLS), of a silicon crystal bender constructed for this purpose are described.
Adaptive optics for high power beam lines using diamond crystal monochromators: Preserving the high source brightness of the third generation of synchrotron radiation facilities will require that thermal and pressure deformations of the monochromator crystals be maintained within a few arc- seconds. Recent experiments at the National Synchrotron Light Source (NSLS) have demonstrated the potential of adaptive crystal optics to cope with high power densities. In this technique the crystals deformations are minimized both by an efficient water-jet cooling and by externally applied pressure loads. Thermal deformation can be reduced further with diamond crystals because of their high thermal conductivity and low coefficient of thermal expansion. In this paper we describe the results achieved by optimization of adaptive crystal optics for diamond crystals.
Adding adsorption to a geothermal simulator: Physical adsorption of steam has increasingly become recognized as an important storage mechanism in vapor dominated geothermal reservoirs. A method has been developed which allows the effects of adsorption to be modeled using TETRAD, a commercially available geothermal simulator. The method consists of replacing the standard steam table with a new steam table which has been derived to include adsorptive effects. The TETRAD simulator, when run with the pseudo steam table, approximately matches the pressure, production, and saturation behavior of a desorbing geothermal system. Adsorption can be described as the existence of an immobile layer of liquid on the surfaces within a porous medium. The presence of an adsorbed liquid water layer in rocks has been shown experimentally to cause the vapor pressure of steam to be lower than its flat surface vapor pressure for a particular The pseudo steam table accounts for this vapor pressure lowering effect. A test run was made with TETRAD using the pseudo steam table and a low porosity, low permeability reservoir matrix. This test run was compared to an equivalent run made with Stanford Geothermal Program's simulator, ADSORB. The program ADSORB is a one dimensional simulator which has adsorption effects built into its difference equations. The comparison of these runs shows that the pseudo steam table allows TETRAD to match the behavior of the ADSORB simulator. Injection was not investigated in this study. A convenient method of modeling adsorption with TETRAD is to use standard steam tables while allowing for the vapor pressure lowering effect of adsorption. This will require modifications of the equations in the code that describe the partial pressure of the steam phase.
ADIFOR: Automatic differentiation in a source translator environment: The numerical methods employed in the solution of many scientific computing problems require the computation of derivatives of a function f: R{sup n} {yields} R{sup m}. ADIFOR (Automatic Differentiation in FORtran) is a source transformation tool that accepts Fortran 77 code for the computation of a function and writes portable Fortran 77 code for the computation of the derivatives. In contrast to previous approaches, ADIFOR views automatic differentiation as a source transformation problem and employs the data analysis capabilities of the ParaScope Fortran programming environment. Experimental results show that ADIFOR can handle real- life codes and that ADIFOR-generated codes are competitive with divided-difference approximations of derivatives. In addition, studies suggest that the source-transformation approach to automatic differentation may improve the time required to compute derivatives by orders of magnitude.
ADIFOR Exception Handling: Automatic differentiation uses recurrence relations based on the rules of calculus. Consequently, the results are guaranteed to be correct only in the relevant mathematical assumptions are satisfied at least in a neighborhood of the current argument. Computer programs may violate these conditions by branching or by calling intrinsic functions such as abs, max, sqrt, and asin at point where their derivative is undefined or infinite. The resulting dependence between the program's input and output variables may still be differentiable, because branch vales fit together smoothly or nondifferentiabilities cancel each other out. We have two objectives. First, we would like to assure the user that the function being evaluated is indeed locally differentiable because all intrinsics are evaluated at smooth arguments and none of the branching tests are critical. Second, the derivative program should run even when the assumptions of the chain rule are not strictly satisfied. In this case, the numerical results represent at least generalized derivations under reasonable (but usually unverifiable) regularity assumptions. To achieve these two goals, we must take into account the effects of finite-precision arithmetic. This paper addresses the detection and handling of exceptions. It is an exception in the ADIFOR-generated code to evaluate a function at a point at which the function may not be mathematically differentiable. When an exception is detected by tests written into the ADIFOR-generated code, an error handler is called. The error handler prints an error message (optionally), halts execution (optionally), and returns a value that allows the user's client program to detect that a requested derivative is not available. Code is included for all of the necessary Fortran intrinsic functions and for the error handler.
ADIFOR Exception Handling. ADIFOR Working Note No. 3: Automatic differentiation uses recurrence relations based on the rules of calculus. Consequently, the results are guaranteed to be correct only in the relevant mathematical assumptions are satisfied at least in a neighborhood of the current argument. Computer programs may violate these conditions by branching or by calling intrinsic functions such as abs, max, sqrt, and asin at point where their derivative is undefined or infinite. The resulting dependence between the program`s input and output variables may still be differentiable, because branch vales fit together smoothly or nondifferentiabilities cancel each other out. We have two objectives. First, we would like to assure the user that the function being evaluated is indeed locally differentiable because all intrinsics are evaluated at smooth arguments and none of the branching tests are critical. Second, the derivative program should run even when the assumptions of the chain rule are not strictly satisfied. In this case, the numerical results represent at least generalized derivations under reasonable (but usually unverifiable) regularity assumptions. To achieve these two goals, we must take into account the effects of finite-precision arithmetic. This paper addresses the detection and handling of exceptions. It is an exception in the ADIFOR-generated code to evaluate a function at a point at which the function may not be mathematically differentiable. When an exception is detected by tests written into the ADIFOR-generated code, an error handler is called. The error handler prints an error message (optionally), halts execution (optionally), and returns a value that allows the user`s client program to detect that a requested derivative is not available. Code is included for all of the necessary Fortran intrinsic functions and for the error handler.
ADIFOR: Fortran source translation for efficient derivatives: The numerical methods employed in the solution of many scientific computing problems require the computation of derivatives of a function f: R{sup n} {yields} R{sup m}. Both the accuracy and the computational requirements of the derivative computation are usually of critical importance for the robustness and speed of the numerical method. ADIFOR (Automatic Differentiation In FORtran) is a source translation tool implemented using the data abstractions and program analysis capabilities of the ParaScope Parallel Programming Environment. ADIFOR accepts arbitrary Fortran-77 code defining the computation of a function and writes portable Fortran-77 code for the computation of its derivatives. In contrast to previous approaches, ADIFOR views automatic differentiation as a process of source translation that exploits computational context to reduce the cost of derivative computations. Experimental results show that ADIFOR can handle real-life codes, providing exact derivatives with a running time that is competitive with the standard divided-difference approximations of derivatives and which may perform orders of magnitude faster than divided-differences in cases. The computational scientist using ADIFOR is freed from worrying about the accurate and efficient computation of derivatives, even for complicated functions,'' and hence, is able to concentrate on the more important issues of algorithm design or system modeling. 35 refs.
ADIFOR Working Note #2: Using ADIFOR to Compute Dense and Sparse Jacobians: ADIFOR is a source translator that, given a collection of Fortran subroutines for the computation of a ``function,`` produces Fortran code for the computation of the derivatives of this function. More specifically, ADIFOR produces code to compute the matrix-matrix product JS, where J is the Jacobian of the ``function`` with respect to the user-defined independent variables, and S is the composition of the derivative objects corresponding to the independent variables. This interface is flexible; by setting S = x, one can compute the matrix-vector product Jx, or by setting S = I, one can compute the whole Jacobian J. Other initializations of S allow one to exploit a known sparsity structure of J. This paper illustrates the proper initialization of ADIFOR-generated derivative codes and the exploitation of a known structure of J.
Adjacency-blurring-effect of scenes modeled by the radiosity method: In this paper we describe a method to simulate images through a scattering atmosphere. We compute the scattering of light from adjacent surfaces into the field-of-view (FOV) with the extended radiosity method. Our simulation takes aerosol scattering phase functions and ground bidirectional reflectance distributions (BRDF) into account. 10 refs.
The ADRIA project for high intensity radioactive beams production: A proposal of an accelerator complex (ADRIA) for the Laboratori Nazionali di Legnaro (LNL) is described in this report. The main components of the complex are a Heavy Ion Injection system and two rings, a Booster and a Decelerator, both with a maximum rigidity of 22.25 Tm, connected by a Transfer Line where exotic proposal has two main goals consisting in the isotopes are produced and selected. The proposal has two main goals consisting in the acceleration of stable ion species up to kinetic energies of the order of few GeV/u, at a repetition rate of 10 Hz with intensities of about 10[sup 12] ions per second, for fixed target experiments in nuclear physics and for the production of fully stripped radioactive beams, using particle fragmentation method for nuclear spectroscopy experiments. Fragments are accumulated in the Decelerator, with intensities 10[sup 8] [divided by] 10[sup 9] ions/s, cooled and delivered at the production energies or decelerated down to energies of few MeV/u, in proximity of the Coulomb barrier.
Adsorption of a binary gas mixture which laterally interacts on a random heterogeneous surface: Analytical expressions for the adsorption of a binary gas mixture which laterally interacts on a heterogeneous surface are developed. The lateral interactions are of the Bragg-Williams type and the surface heterogeneity is modeled via a random distribution of sites described by a uniform distribution of Henry's Law constants. The parametric study shows that complex phase behavior can be predicted, including azeotropes and sigmoidal shaped X-Y diagrams. Also, this model may be useful for modeling and designing adsorption processes as it requires few iterations to simultaneously solve the implicit and coupled algebraic expressions.
Adsorption of aniline and toluidines on montmorillonite: Implications for the disposal of shale oil production wastes: Bentonite clay liners are commonly employed to mitigate the movement of contaminants from waste disposal sites. Solid and liquid waste materials that arise from the production of shale oil contain a vast array of organic compounds. Common among these compounds are the aromatic amines. in order to assess the ability of clay liner material to restrict organic compound mobility, the adsorption of aniline and o-, m-, and p-toluidine on Ca{sup 2+} - and K{sup +}-saturated Wyoming bentonite was investigated. Adsorption experiments were performed under conditions of varied pH, ionic strength, and dominate electrolyte cation and anion. organic adsorption on Ca{sup 2+} - and K{sup +}-saturated montmorillonite is pH dependent. For any given organic compound, maximum adsorption increases with decreasing ionic strength. organic compound adsorption is inhibited in the presence of sulfate and is greater in the Ca{sup 2+} systems than in the K{sup +} systems at any given ionic strength. High salt content and K{sup +} collapse the bentonite layers and limit access to and compete for adsorption sites. The K{sup +} ion is also more difficult to displace than Ca{sup 2+} from interlayer positions. Fourier transform infrared spectroscopic data show that the aniline compounds are adsorbed on bentonite through the hydrogen bonding of an amine hydrogen to a surface silica oxygen. Sulfate reduces amine adsorption by removing positively charged anilinium species from solution to form negatively charge sulfate complexes. Although adsorption of the substituted amines on bentonite is observed, aniline and toluidine adsorption is minimal in saline systems and not detected in alkaline systems. Thus, in shale oil process waste disposal sites, the mobility of the anilines through bentonite liners will not be mitigated by sorption processes, as spent oil shale leachates are both highly alkaline and saline.
Adsorption of aniline and toluidines on montmorillonite: Implications for the disposal of shale oil production wastes: Bentonite clay liners are commonly employed to mitigate the movement of contaminants from waste disposal sites. Solid and liquid waste materials that arise from the production of shale oil contain a vast array of organic compounds. Common among these compounds are the aromatic amines. in order to assess the ability of clay liner material to restrict organic compound mobility, the adsorption of aniline and o-, m-, and p-toluidine on Ca[sup 2+] - and K[sup +]-saturated Wyoming bentonite was investigated. Adsorption experiments were performed under conditions of varied pH, ionic strength, and dominate electrolyte cation and anion. organic adsorption on Ca[sup 2+] - and K[sup +]-saturated montmorillonite is pH dependent. For any given organic compound, maximum adsorption increases with decreasing ionic strength. organic compound adsorption is inhibited in the presence of sulfate and is greater in the Ca[sup 2+] systems than in the K[sup +] systems at any given ionic strength. High salt content and K[sup +] collapse the bentonite layers and limit access to and compete for adsorption sites. The K[sup +] ion is also more difficult to displace than Ca[sup 2+] from interlayer positions. Fourier transform infrared spectroscopic data show that the aniline compounds are adsorbed on bentonite through the hydrogen bonding of an amine hydrogen to a surface silica oxygen. Sulfate reduces amine adsorption by removing positively charged anilinium species from solution to form negatively charge sulfate complexes. Although adsorption of the substituted amines on bentonite is observed, aniline and toluidine adsorption is minimal in saline systems and not detected in alkaline systems. Thus, in shale oil process waste disposal sites, the mobility of the anilines through bentonite liners will not be mitigated by sorption processes, as spent oil shale leachates are both highly alkaline and saline.
Advanced Coal Liquefaction Research and Development Facility, Wilsonville, Alabama: This report presents the results of Run 260 performed at the Advanced Coal Liquefaction R D Facility in Wilsonville. The run was started on July 17, 1990 and continued until November 14, 1990, operating in the Close-Coupled Integrated Two-Stage Liquefaction mode processing Black Thunder mine subbituminous coal (Wyodak-Anderson seam from Wyoming Powder River Basin). Both thermal/catalytic and catalytic/thermal tests were performed to determine the methods for reducing solids buildup in a subbituminous coal operation, and to improve product yields. A new, smaller interstage separator was tested to reduce solids buildup by increasing the slurry space velocity in the separator. In order to obtain improved coal and resid conversions (compared to Run 258) full-volume thermal reactor and 3/4-volume catalytic reactor were used. Shell 324 catalyst, 1/16 in. cylindrical extrudate, at a replacement rate of 3 lb/ton of MF coal was used in the catalytic stage. Iron oxide was used as slurry catalyst at a rate of 2 wt % MF coal throughout the run. (TNPS was the sulfiding agent.)
Advanced Coal Liquefaction Research and Development Facility, Wilsonville, Alabama. Run 260 with Black Thunder Mine subbituminous coal: Technical progress report: This report presents the results of Run 260 performed at the Advanced Coal Liquefaction R&D Facility in Wilsonville. The run was started on July 17, 1990 and continued until November 14, 1990, operating in the Close-Coupled Integrated Two-Stage Liquefaction mode processing Black Thunder mine subbituminous coal (Wyodak-Anderson seam from Wyoming Powder River Basin). Both thermal/catalytic and catalytic/thermal tests were performed to determine the methods for reducing solids buildup in a subbituminous coal operation, and to improve product yields. A new, smaller interstage separator was tested to reduce solids buildup by increasing the slurry space velocity in the separator. In order to obtain improved coal and resid conversions (compared to Run 258) full-volume thermal reactor and 3/4-volume catalytic reactor were used. Shell 324 catalyst, 1/16 in. cylindrical extrudate, at a replacement rate of 3 lb/ton of MF coal was used in the catalytic stage. Iron oxide was used as slurry catalyst at a rate of 2 wt % MF coal throughout the run. (TNPS was the sulfiding agent.)
Advanced direct coal liquefaction concepts: During the first quarter of FY 1993, the Project proceeded close to the Project Plan. The analysis of the feed material has been completed as far as possible. Some unplanned distillation was needed to correct the boiling range of the Black Thunder solvent used during the autoclave tests. Additional distillation will be required if the same solvent is to be used for the bench unit tests. A decision on this is still outstanding. The solvent to be used with Illinois No. 6 coal has not yet been defined. As a result, the procurement of the feed and the feed analysis is somewhat behind schedule. Agglomeration tests with Black Thunder coal indicates that small agglomerates can be formed. However, the ash removal is quite low (about 10%), which is not surprising in view of the low ash content of the coal. The first series of autoclave tests with Black Thunder coal was completed as planned. Also, additional runs are in progress as repeats of previous runs or at different operating conditions based on the data obtained so far. The results are promising indicating that almost complete solubilization (close to 90%) of Black Thunder coal can be achieved in a CO/H[sub 2]O environment at our anticipated process conditions. The design of the bench unit has been completed. In contrast to the originally planned modifications, the bench unit is now designed based on a computerized control and data acquisition system. All major items of equipment have been received, and prefabrication of assemblies and control panels is proceeding on schedule. Despite a slight delay in the erection of the structural steel, it is anticipated that the bench unit will be operational at the beginning of April 1993.
Advanced lightweight ceramic candle filter module: To determine the economic effect of light weight ceramics, several sizes of filters were cost estimated for operation at 217.5 psi (15 bar) based on the use of all light weight ceramics (Fibro/Fibro) vs. the use of cooled alloy (RA300) tubesheets and silicon carbide candles (Alloy/SiC). A jet pulse delivery system was included in both estimates. The Fibro/Fibro system was estimated with the plenum design while the Alloy/SiC system was based on header/nozzle design. Battery limits were the filters and jet pulse delivery systems, Ex-works, with no main valves or dust removal systems. It was found that the cost of Fibro/Fibro components were consistently lower than the cost of the Alloy/SiC components; this comparison is illustrated in Figure 8.
Advanced Neutron Source (ANS) Project Progress report, FY 1991: This report discusses the following about the Advanced Neutron Source: Project Management; Research and Development; Fuel Development; Corrosion Loop Tests and Analyses; Thermal-Hydraulic Loop Tests; Reactor Control and Shutdown Concepts; Critical and Subcritical Experiments; Material Data, Structural Tests, and Analysis; Cold-Source Development; Beam Tube, Guide, and Instrument Development; Hot-Source Development; Neutron Transport and Shielding; I & C Research and Development; Design; and Safety.
Advanced Neutron Source (ANS) Project Progress report, FY 1991: This report discusses the following about the Advanced Neutron Source: Project Management; Research and Development; Fuel Development; Corrosion Loop Tests and Analyses; Thermal-Hydraulic Loop Tests; Reactor Control and Shutdown Concepts; Critical and Subcritical Experiments; Material Data, Structural Tests, and Analysis; Cold-Source Development; Beam Tube, Guide, and Instrument Development; Hot-Source Development; Neutron Transport and Shielding; I C Research and Development; Design; and Safety.
Advanced NMR Approaches in the Characterization of Coal: A considerable effort in this project during the past few months has been focussed on the development of [sup 1]H and [sup 13]C NMR imaging techniques to yield spatially-resolved chemical shift (structure) information on coal. In order to yield the chemical shift information, a solid-state NMR imaging technique must include magic-angle spinning, so rotating gradient capabilities are indicated. A [sup 13]C MAS imaging probe and a [sup 1]H MAS imaging probe and the circuitry necessary for rotating gradients have been designed and constructed. The [sup 1]H system has already produced promising preliminary results, which are briefly described in this report.
Advanced Nmr Approaches in the Characterization of Coal: The paper submitted earlier on the use of (bicyclo[3.2.1]4pyrrolidino-N-methyl-octan-8-one triflate) ([sup 13]CO-123) as a [sup 13]C intensity standard was accepted for publication. Subsequently, [sup 13]CO-321 was used in this manner for quantitative [sup 13]C CP-MAS NMR analysis (including spin counting) of Argonne Premium coals. The cross-polarization time constants, T[sub CH], and the rotating-frame proton spin-lattice relaxation times, T[sub 1p][sup H], were determined for each major peak of each coal via a combination of variable contact-time and variable spin-lock (T[sub 1p][sup H]) experiments. Two or three components of rotating-frame [sup 1]H relaxation decay and two or three components of T[sub CH] behavior were observed for each major [sup 13]C peak of each coal. These data were used to determine the number of carbon atoms detected in each coal; these values are in the range between 77% and 87% of the amount of carbon known to be in each coal from elemental analysis data, except for Pocahontas No. 3, for which only 50% of the carbon was detected. In an attempt to use [sup 1]H CRAMPS to elucidate chemical functionality in coal, pyridine-saturated samples of the Argonne Premium coals were examined in detail in terms of their [sup 1]H CRAMPS NMR spectra. These spectra were deconvoluted to yield relative concentrations for individual peaks.
Advanced NMR-based techniques for pore structure analysis of coal: One of the main problems in coal utilization is the inability to properly characterize its complex pore structure. Coals typically have micro/ultra-micro pores but they also exhibit meso and macroporosity. We believe that measurement of the NMR parameters of various gas phase and adsorbed phase NMR active probes can provide the resolution to this problem. We will investigate the dependence of the common NMR parameters such as chemical shifts and relaxation times of several different nuclei and compounds on the pore structure of model microporous solids, carbons, and coals. In particular, we will study the interaction between several small molecules ({sup 129}Xe, {sup 3}He, {sup 2}H{sub 2}, {sup 14}N{sub 2}, {sup 14}NH{sub 3}, {sup 15}N{sub 2}, {sup 13}CH{sub 4}, {sup 13}CO{sub 2}) and the pore surfaces in coals. These molecules have been selected for their chemical and physical properties. A special NMR probe will be constructed which will allow the concurrent measurement of NMR properties and adsorption uptake at a variety of temperatures. All samples will be subjected to a suite of conventional'' pore structure analyses. These include nitrogen adsorption at 77 K with BET analysis, C0{sub 2} and CH{sub 4} adsorption at 273 K with D-R (Dubinin-Radushkevich) analysis, helium pycnometry, and small angle X-ray scattering as well as gas diffusion measurements. The project combines expertise at the UNM (pore structure, NMR), Los Alamos National Laboratory (NMR), and Air Products (porous materials).
Advanced NMR-based techniques for pore structure analysis of coal: One of the main problems in coal utilization is the inability to properly characterize its complex pore structure. Coals typically have micro/ultra-micro pores but they also exhibit meso and macroporosity. Conventional pore size techniques (adsorption/condensation, mercury porosimetry) are limited because of this broad pore size range, microporosity, reactive nature of coal, samples must be completely dried, and network/percolation effects. Small angle scattering is limited because it probes both open and closed pores. Although one would not expect any single technique to provide a satisfactory description of a coal's structure, it is apparent that better techniques are necessary. We believe that measurement of the NMR parameters of various gas phase and adsorbed phase NMR active probes can provide the resolution to this problem. We will investigate the dependence of the common NMR parameters such as chemical shifts and relaxation times of several different nuclei and compounds on the pore structure of model microporous solids, carbons, and coals. In particular, we will study the interaction between several small molecules and the pore surfaces in coals. These molecules have been selected for their chemical and physical properties. A special NMR probe will be constructed which will allow the concurrent measurement of NMR properties and adsorption uptake at a variety of temperatures. All samples will be subjected to a suite of conventional'' pore structure analyses. These include nitrogen adsorption at 77 K with BET analysis, CO[sub 2] and CH[sub 4] adsorption at 273 K with D-R (Dubinin-Radushkevich) analysis, helium pycnometry, and small angle X-ray scattering as well as gas diffusion measurements.
Advanced NMR-based techniques for pore structure analysis of coal: One of the main problems in coal utilization is the inability to properly characterize its complex pore structure. Coals typically have micro/ultra-micro pores but they also exhibit meso and macroporosity. Conventional pore size techniques (adsorption/condensation, mercury porosimetry) are limited because of this broad pore size range, microporosity, reactive nature of coal, samples must be completely dried, and network/percolation effects. Small angle scattering is limited because it probes both open and closed pores. Although one would not expect any single technique to provide a satisfactory description of a coal's structure, it is apparent that better techniques are necessary. We believe that measurement of the NMR parameters of various gas phase and adsorbed phase NMR active probes can provide the resolution to this problem. We now have two suites of well-characterized microporous materials including oxides (zeolites and silica gel) and activated carbons from our industrial partner, Air Products in Allentown, PA. Our current work may be divided into three areas: small-angle X-ray scattering (SAXS), adsorption, and NMR.
The Advanced Photon Source: A status report: The Advanced Photon Source (APS) currently under construction at Argonne National Laboratory is scheduled for completion in early 1996. Both conventional facilities construction and technical fabrication is well underway. An update on the current state of civil construction as well as progress on storage ring and beamline technical component development will be presented. User activities have also proceeded at a rapid pace, particularly over the last year. In response to a call for Proposals for sectors, the APS received proposals for over twenty sectors from prospective Collaborative Access Teams (CATs). It is anticipated that beamline construction in the experiment hall could begin in approximately 18 months.
The Advanced Photon Source: A status report: The Advanced Photon Source (APS) currently under construction at Argonne National Laboratory is scheduled for completion in early 1996. Both conventional facilities construction and technical fabrication is well underway. An update on the current state of civil construction as well as progress on storage ring and beamline technical component development will be presented. User activities have also proceeded at a rapid pace, particularly over the last year. In response to a call for Proposals for sectors, the APS received proposals for over twenty sectors from prospective Collaborative Access Teams (CATs). It is anticipated that beamline construction in the experiment hall could begin in approximately 18 months.

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