A computerized mathematical model for anion exchange processing of plutonium(IV) was adopted from a previously written code. The model was verified to predict, within +-30 percent, a profile of plutonium breakthrough for the sorption process on Dowex 1-X4 anion exchange resin. The program was modified to incorporate column washing and elution logic. Experimental washing and elution data were in satisfactory agreement with predicted data. Provisions for changing the flow rate during the course of a run and for plotting capabilities to aid in better presentation of column breakthrough curves also were incorporated into the model.

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Using dielectric wall accelerator technology, we are developing a compact induction accelerator system primarily intended for pulsed radiography. The accelerator would provide a 2-kA beam with an energy of 8 MeV, for a 20-30 ns flat-top. The design goal is to generate a 2-mm diameter, 10-rad x-ray source. We have a physics design of the system from injector to the x-ray converter. We present the results of injector modeling and PIC simulations of beam transport. We also discuss the predicted spot size and the on-axis x-ray dose.

Releasing the energy stored in an isomeric nuclear state in a controlled way with an atomic or electromagnetic trigger is an attractive speculation: the energy gain may be on the order of the ratio of nuclear/atomic energies - MeV/keV. (Nuclear isomers are loosely defined as excited nuclear states with lifetimes longer than 10{sup -9} s.) Nuclear isomers, therefore, represent an opportunity for a stand-alone energy source if suitable schemes for trigger and control of the energy release can be found. Potential applications include space drive, as well as very bright {gamma}-ray sources. The nucleus {sup 178}Hf has a nuclear isomer with excitation energy E{sub x} = 2.447 MeV. The 2.447-MeV isomeric state decays slowly (t{sub 1/2} = 31 y) to the nearby state at 2.433 MeV. The J{sup {pi}} = 13{sup -} state loses energy in a rapid (t {approx} 10{sup -12} s) {gamma}-ray cascade ending at the 8{sup -} rotational band head which in turn decays via the ground-state rotational band cascade. The {gamma}-ray cascade is delayed at the 8{sup -} state at 1.147 MeV, since the 8{sup -} state is also isomeric, with t{sub 1/2} = 4 s. Very scarce quantities of the 16{sup +}, 31-yr isomer are …

The warm plasma from a deuterium-loaded titanium washer gun, streaming along magnetic-field lines through the steady-state magnetic well of Baseball II, has been examined for its suitability in this experimental situation as a target plasma for hot-ion buildup experiments and for microinstability control. The gun was positioned near the magnetic axis outside the mirror region. Measurements were made with gridded, end-loss detectors placed outside the opposite mirror, a microwave interferometer, a beam-attenuation detector, and other diagnostics.

Embedded systems often have real-time constraints. Traditional timing analysis statically determines the maximum execution time of a task or a program in a real-time system. These systems typically depend on the worst-case execution time of tasks in order to make static scheduling decisions so that tasks can meet their deadlines. Static determination of worst-case execution times imposes numerous restrictions on real-time programs, which include that the maximum number of iterations of each loop must be known statically. These restrictions can significantly limit the class of programs that would be suitable for a real-time embedded system. This paper describes work-in-progress that uses static timing analysis to aid in making dynamic scheduling decisions. For instance, different algorithms with varying levels of accuracy may be selected based on the algorithm's predicted worst-case execution time and the time allotted for the task. We represent the worst-case execution time of a function or a loop as a formula, where the unknown values affecting the execution time are parameterized. This parametric timing analysis produces formulas that can then be quickly evaluated at run-time so dynamic scheduling decisions can be made with little overhead. Benefits of this work include expanding the class of applications that can be …

We used high resolution Atomic Force Microscopy (AFM) to image compaction of linear and circular DNA by the yeast mitochondrial protein ABF2p , which plays a major role in maintaining mitochondrial DNA. AFM images show that protein binding induces drastic bends in the DNA backbone for both linear and circular DNA. At high concentration of ABF2p DNA collapses into a tight globular structure. We quantified the compaction of linear DNA by measuring the end-to-end distance of the DNA molecule at increasing concentrations of ABF2p. We also derived a polymer statistical mechanics model that gives quantitative description of compaction observed in our experiments. This model shows that a number of sharp bends in the DNA backbone is often sufficient to cause DNA compaction. Comparison of our model with the experimental data showed excellent quantitative correlation and allowed us to determine binding characteristics for ABF2. Our studies indicate that ABF2 compacts DNA through a novel mechanism that involves bending of DNA backbone. We discuss the implications of such a mechanism for mitochondrial DNA maintenance.

The Physics and Advanced Technologies (PAT) Directorate was created in July 2000 by Bruce Tarter, Director of Lawrence Livermore National Laboratory (LLNL). The Director called for the new organization to execute and support programs that apply cutting-edge physics and advanced technology to develop integrated solutions to problems in national security, fusion energy, information science, health care, and other national grand challenges. When I was appointed a year later as the PAT Directorate's first Associate Director, I initiated a strategic planning project to develop a vision, mission, and long-term goals for the Directorate. We adopted the goal of becoming a leader in frontier physics and technology for twenty-first-century national security missions: Stockpile Stewardship, homeland security, energy independence, and the exploration of space. Our mission is to: (1) Help ensure the scientific excellence and vitality of the major LLNL programs through its leadership role in performing basic and applied multidisciplinary research and development with programmatic impact, and by recruiting and retaining science and technology leaders; (2) Create future opportunities and directions for LLNL and its major programs by growing new program areas and cutting-edge capabilities that are synergistic with, and supportive of, its national security mission; (3) Provide a direct conduit to …

A better understanding of thermal cook-off is important for safe handling and storing explosive devices. A number of safety issues exist about what occurs when a cased explosive thermally cooks off. For example, violence of the events as a function of confinement are important for predictions of collateral damage. This paper demonstrates how adjacent materials can be gauged to measure the resulting pressure wave and how this wave propagates in this adjacent material. The output pulse from the thermal cook-off explosive containing fixture is of obvious interest for assessing many scenarios.

Within the scope of conceptual research and development (R&D) activities in support of the Rare Isotope Accelerator (RIA) facility, high priority is given to the development of high-power fragmentation beam dumps. A pre-study was made of a static water-cooled Cu beam dump that can meet requirements for a 400 MeV/u uranium beam. The issue of beam sputtering was addressed and found to be insignificant. Preliminary radiation transport simulations show significant damage (in displacements per atom, DPA) in the vicinity of the Bragg peak of the uranium ions. Experimental data show that defects in Cu following neutron or high-energy particle irradiation tend to saturate at doses between 1 and 5 DPA, and this saturation in defect density also results in saturation of mechanical property degradation. However, effects of swift heavy ion irradiation and the production of gaseous and solid transmutant elements still need to be addressed. Initial calculations indicate that He concentrations on the order of 400 appm are produced in the beam dump after several weeks of continuous operation and He embrittlement may be a concern. Recommendations are made for further investigation of Cu irradiation effects for RIA-relevant conditions.

The differential cross section of the process p + pbar {yields} jet + jet + X as a function of the dijet invariant mass has been measured with the CDF detector at a center of mass energy of 1.8 TeV at the Tevatron Collider in Fermilab. The present analysis is based on the sample of events collected in the 1988/89 run, amounting to a total integrated luminosity of 4.2 pb{sup {minus}1}. A comparison to leading order QCD and quark compositeness predictions is presented as well as a study of the sensitivity of the mass spectrum to the gluon radiation. 10 refs., 6 figs.

SUNDIALS [2], SUite of Nonlinear and DIfferential/ALgebraic equation Solvers, is a family of software tools for integration of ODE and DAE initial value problems and for the solution of nonlinear systems of equations. It consists of CVODE, IDA, and KINSOL, and variants of these with sensitivity analysis capabilities. SUNDIALSTB is a collection of MATLAB functions which provide interfaces to the SUNDIALS solvers. The core of each MATLAB interface in SUNDIALSTB is a single MEX file which interfaces to the various user-callable functions for that solver. However, this MEX file should not be called directly, but rather through the user-callable functions provided for each MATLAB interface. A major design principle for SUNDIALSTB was to provide an interface that is, as much as possible, equally familiar to users of both the SUNDIALS codes and MATLAB. Moreover, we tried to keep the number of user-callable functions to a minimum. For example, the CVODES MATLAB interface contains only 9 such functions, 3 of which interface solely to the adjoint sensitivity module in CVODES. In tune with the MATLAB ODESET function, optional solver inputs in SUNDIALSTB are specified through a single function (CvodeSetOptions for CVODES). However, unlike the ODE solvers in MATLAB, we have kept …

Laboratory measurements of the electrical resistivity of fractured analogue geothermal reservoir rocks were performed to investigate the resistivity contrast caused by active boiling and to determine the effects of variable fracture dimensions and surface area on water extraction. Experiments were performed at confining pressures up to 10 h4Pa (100 bars) and temperatures to 170 C. Fractured samples show a larger resistivity change at the onset of boiling than intact samples. Monitoring the resistivity of fractured samples as they equilibrate to imposed pressure and temperature conditions provides an estimate of fluid migration into and out of the matrix. Measurements presented are an important step toward using field electrical methods to quantitatively search for fractures, infer saturation, and track fluid migration in geothermal reservoirs.

Many rivers are burdened with tributary streams of warm water and/or liquid wastes containing dissolved or suspended matter. The warm water and waste matter mix thoroughly with the river water some distance downstream from the point of entry of the tributary, but near the point of entry there may be high local temperatures or concentrations of waste. It is often necessary to know the local temperatures or concentrations of waste. The authors have used a formula for computing the turbulent mixing that takes place in such a situation; this formula fits quite well in the case of one Southern river.

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In this document the author describes an extension of the spatial gridding techniques to an MHD model suitable for the description of the dynamics of toroidal fusion devices. Since the dominant MHD modes in these devices have relatively long toroidal wavelength, the toroidal coordinate is approximated with finite Fourier series. The unstructured, triangular mesh is used to describe the details of the poloidal geometry. With some exceptions, the hydrodynamic variables are treated in a manner analogous to that used in CFD. These quantities (mass, energy, and momentum) are volume based densities that satisfy scalar or vector conservation laws. The electromagnetic variables (the magnetic flux density B and the electric current density J) are area based densities that satisfy pseudo-vector conservation laws, and have no counterpart in fluid dynamics. These variables are also constrained to remain solenoidal. These quantities are represented on the triangular mesh in a new manner that is an extension of that used on rectangular, structured meshes. In this work the author has chosen to solve the primitive MHD equations in order to make the resulting codes and techniques more generally applicable to problems beyond the narrow scope of tokamak plasmas. The temporal stiffness problems inherent in this …

Advances in data collection and storage capabilities during the past decades have led to an information overload in most sciences. Researchers working in domains as diverse as engineering, astronomy, biology, remote sensing, economics, and consumer transactions, face larger and larger observations and simulations on a daily basis. Such datasets, in contrast with smaller, more traditional datasets that have been studied extensively in the past, present new challenges in data analysis. Traditional statistical methods break down partly because of the increase in the number of observations, but mostly because of the increase in the number of variables associated with each observation. The dimension of the data, is the number of variables that are measured on each observation. High-dimensional datasets present many mathematical challenges as well as some opportunities, and are bound to give rise to new theoretical developments. One of the problems with high-dimensional datasets is that, in many cases, not all the measured variables are ''important'' for understanding the underlying phenomena of interest. While certain computationally expensive novel methods can construct predictive models with high accuracy from high-dimensional data, it is still of interest in many applications to reduce the dimension of the original data prior to any modeling of …

A research-scale, liquid-fed, ceramic-melter was used to conduct a flowsheet evaluation of a nonradioactive surrogate of sodium-bearing waste currently being stored in underground tanks at the Department of Energy?s Idaho National Engineering and Environmental Laboratory. During this 120-h melter test, the processing characteristics of a glass formulated to have a high sulfur capacity were evaluated with and without reductant (sucrose and glycolic acid) additives. Beyond processing rates, this integrated melter/off-gas system demonstration test evaluated the impacts of reductant type (if used) and concentration upon 1) the partitioning of volatile (sulfur, mercury, and the halogens) and nonvolatile effluents, 2) the oxidation state of the melter glass, 3) the reduction of waste constituent nitrate, 4) the composition of secondary waste streams, and 5) the durability of the melter?s glass product.

The stochastic engine uses modern computational capabilities to combine simulations with observations. We integrate the general knowledge represented by models with specific knowledge represented by data, using Bayesian inferencing and a highly efficient staged Metropolis-type search algorithm. From this, we obtain a probability distribution characterizing the likely configurations of the system consistent with existing data. The primary use will be optimizing knowledge about the configuration of a system for which sufficient direct observations cannot be made. Programmatic applications include underground systems ranging from environmental contamination to military bunkers, optimization of complex nonlinear systems, and timely decision-making for complex, hostile environments such as battlefields or the detection of secret facilities. We create a stochastic ''base representation'' of system configurations (states) from which the values of measurable parameters can be calculated using forward simulators. Comparison of these predictions to actual measurements drives embedded Bayesian inferencing, updating the distributions of states in the base representation using the Metropolis method. Unlike inversion methods that generate a single bestcase deterministic solution, this method produces all the likely solutions, weighted by their likelihoods. This flexible method is best applied to highly non-linear, multi-dimensional problems. Staging of the Metropolis searches permits us to run the simplest model …

The primary objective of the present Phase 3 effort is to perform the final testing at a 20 MNBtu/hr commercial scale of an air cooled, slogging coal combustor for application to industrial steam boilers and power plants. The focus of the test effort will be on combustor durability, automatic control of the combustor`s operation, and optimum environmental control of emissions inside the combustor. In connection with the latter, the goal is to achieve 0.4 lb/MMBtu of SO{sub 2} emissions, 0.2 lb/MMBtu of NO{sub x} emissions, and 0.02 lb particulate/MMBtu. Meeting the particulate goal will require the use of a baghouse or electrostatic precipitator to augment the nominal 80% ash retention in the combustor. The NO{sub x} emission goal will require a modest improvement over reductions achieved to date in the combustor of 0.26 lb/MNBtu. To reach the SO{sub 2} emissions goal inside the combustor may require a combination of reduction inside the combustor and inside the boiler by injection of suitable sorbents. To date, SO{sub 2} levels as low as 0.6 lb/MNBtu, equal to 81% reduction in 2% sulfur coals, have been measured with boiler injection of sorbents.

The instrument has four basic components: OEM analytical balance, pivot point and capacitor plates for sensing and controlling the position of the long inverted pendulum, gas confinement tower and high voltage bias electrodes, and furnace. Work during the second quarter has resulted in detailed design of the pivot point and capacitive sensing and control assembly to be attached onto the platen of a Denver Instruments A-series analytical balance.

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The DWPF Development Plan is based on an evaluation process flowsheet and related waste management systems. The scope is shown in Figure 1 entitled ``DWPF Process Development Systems.`` To identify the critical development efforts, each system has been analyzed to determine: The identification of unresolved technology issues. A technology issue (TI) is one that requires basic development to resolve a previously unknown process or equipment problem and is managed via the Technology Assurance Program co-chaired by DWPF and SRTC. Areas that require further work to sufficiently define the process basis or technical operating envelop for DWPF. This activity involves the application of sound engineering and development principles to define the scope of work required to complete the technical data. The identification of the level of effort and expertise required to provide process technical consultation during the start-up and demonstration of this first of a kind plant.

During April 1962, equipment in both the main Redox Building (202-S) and the Plutonium Concentration Building (233-S) vas rearranged to allow the accumulation and recovery of neptunium without interference with the production of uranium and plutonium. In order to do this, the former rework column (1S) was put into continuous service as a neptunium recovery column, the Third Plutonium Cycle was converted to a neptunium decontamination cycle, and ion-exchange equipment was installed in the 233-S Building to replace the Third Plutonium Cycle. The neptunium, once decontaminated, will be concentrated and loaded out via its own system in the 233-S Building. To check the critical mass safety of the new arrangement, a formal hazards review was made, the results of which are reported in this document.