Increasingly in industry, software design and implementation is object-oriented, developed in C++ or Java, and relies heavily on pre-existing software libraries (e.g. the Microsoft Foundation Classes for C++, the Java API for Java). A similar but more tentative trend is developing in high-performance parallel scientific computing. The transition from serial to parallel application development considerably increases the need for library support: task creation and management, data distribution and dynamic redistribution, and inter-process and inter-processor communication and synchronization must be supported. PADRE is a library to support the interoperability of parallel applications. We feel there is significant need for just such a tool to compliment the many domain-specific application frameworks presently available today, but which are generally not interoperable.

Modern antennas especially arrays are being placed in layers of materials on complex environments. This technique produces aesthetically pleasing structures if necessary, allows for more freedom in structure planning, and can improve antenna performance. In the past, buried antennas have been studied by numerous authors such as in Reference. Recent work on this subject uses spectral and/or numerical moment method formulations. For high frequency analysis it is important to find efficient and accurate methods for design purposes. A rigorous recursive method for plane waves reflection and transmission coefficients by Richmond has been used in the past for dipoles above multilayer slabs. This solution is modified in this paper to account for forward and backward traveling rays with appropriate spread factors for a dipole in the media. Extensive validation for this approximate method shows good agreement with a Method of Moments code. This code is developed at Lawrence Livermore National Laboratory. The geometry for these comparisons uses a dipole in nontruncated dielectric multilayer slabs.

The possibility of fast ignition of thermo-nuclear fusion is stimulating research interest and activity worldwide. Fast ignition (FI) offers significantly higher gain than conventional spark ignition and the high gain opens the way to an efficient fusion energy producing cycle with laser drivers. The key to FI is the efficient transport of energy from a short pulse laser beam, the igniter, to a small ignition spark in compressed deuterium-tritium fuel. The primary candidate process enabling such energy transfer, is the absorption of laser light and its conversion into a beam of relativistic electrons, which heats the spark. Theory has predicted self-induced magnetic collimation of the electron beam, which could enable efficient transport from the absorption point to the ignition spark. Experiments are required to understand this highly complex process which involves currents in the electron beam, which greatly exceed the Alfven current limit6 (at which the Larmor radius of an electron in the magnetic field associated with by the current is smaller than the radius of the beam). Almost complete current compensation by cold electron return current is therefore required. The oppositely directed hot and cold electron flows initiate strong growth of the Weibel instability, which causes the currents to …

We consider an interior penalty discontinuous approximation for symmetric elliptic problems of second order on non-matching grids in this paper. The main result is an almost optimal error estimate for the interior penalty approximation of the original problem based on the partition of the domain into a finite number of subdomains. Further, an error analysis for the finite element approximation of the penalty formulation is given. Finally, numerical experiments on a series of model second order problems are presented.

An adaptive path planning algorithm is presented for cooperating Unmanned Air Vehicles (UAVs) that are used to deploy and operate land-based sensor networks. The algorithm employs a global cost function to generate paths for the UAVs, and adapts the paths to exceptions that might occur. Examples are provided of the paths and adaptation.

The authors discuss the decay of axion walls bounded by strings and present numerical simulations of the decay process. In these simulations, the decay happens immediately, in a time scale of order the light travel time, and the average energy of the radiated axions is <w{sub a}> {approx_equal} 7m{sub a} for v{sub a}/m{sub a} {approx_equal} 500. <w{sub a}> is found to increase approximately linearly with ln(v{sub a}/m{sub a}). Extrapolation of this behavior yields <w{sub a}> {approx_equal} 60 m{sub a} in axion models of interest.

Adaptive mesh refinement is complicated by both the algorithms and the dynamic nature of the computations. In parallel the complexity of getting good performance is dependent upon the architecture and the application. Most attempts to address the complexity of AMR have lead to the development of library solutions, most have developed object-oriented libraries or frameworks. All attempts to date have made numerous and sometimes conflicting assumptions which make the evaluation of performance of AMR across different applications and architectures difficult or impracticable. The evaluation of different approaches can alternatively be accomplished through simulation of the different AMR processes. In this paper we outline our research work to simulate the processing of adaptive mesh refinement grids using a distributed array class library (P++). This paper presents a combined analytic and empirical approach, since details of the algorithms can be readily predicted (separated into specific phases), while the performance associated with the dynamic behavior must be studied empirically. The result, AMRSim, provides a simple way to develop bounds on the expected performance of AMR calculations subject to constraints given by the algorithms, frameworks, and architecture.

Lowering the costs of front-end processes in the geologic sequestration of CO{sub 2} can dramatically lower the overall costs. One approach is to sequester less-pure CO{sub 2} waste streams that are less expensive or require less energy to separate from flue gas, a coal gasification process, etc. The objective of this research is to evaluate the impacts of an impure CO{sub 2} waste stream on geologic sequestration using both reaction progress and reactive transport simulators. The simulators serve as numerical laboratories within which a series of computational experiments can be designed, carried out, and analyzed to quantify sensitivity of the overall injection/sequestration process to specific compositional, hydrologic, structural, thermodynamic, and kinetic parameters associated with the injection fluid and subsurface environment.

Gene Recovery Microdissection (GRM) is a unique and cost-effective process for producing chromosome region-specific libraries of expressed genes. It accelerates the pace, reduces the cost, and extends the capabilities of functional genomic research, the means by which scientists will put to life-saving, life-enhancing use their knowledge of any plant or animal genome.

Lawrence Livermore National Laboratory (LLNL) is a large Superfund site in California that is implementing an extensive ground water remediation program. The site is underlain by a thick sequence of heterogeneous alluvial sediments. Defining ground-water flow pathways in this complex geologic setting is difficult. To better evaluate these pathways, a deterministic approach was applied to define hydrostratigraphic units (HSUS) on the basis of identifiable hydraulic behavior and contaminant migration trends. The conceptual model based on this approach indicates that groundwater flow and contaminant transport occurs within packages of sediments bounded by thin, low-permeability confining layers. To aid in the development of the remediation program, a three-dimensional finite-element model was developed for two of the HSUS at LLNL. The primary objectives of this model are to test the conceptual model with a numerical model, and provide well field management support for the large ground-water remediation system. The model was successfully calibrated to 12 years of ground water flow and contaminant transport data. These results confirm that the thin, low-permeability confining layers within the heterogeneous alluvial sediments are the dominant hydraulic control to flow and transport. This calibrated model is currently being applied to better manage the large site-wide ground water extraction …

Libraries arise naturally from the increasing complexity of developing scientific applications, the optimization of libraries is just one type of high-performance optimization. Many complex applications areas can today be addressed by domain-specific object-oriented frameworks. Such object-oriented frameworks provide an effective compliment to an object-oriented language and effectively permit the design of what amount to essentially domain-specific languages. The optimization of such a domain-specific library/language combination however is particularly complicated due to the inability of the compiler to optimize the use of the libraries abstractions. The recognition of the use of object-oriented abstractions within user applications is a particularly difficult but important step in the optimization of how objects are used within expressions and statements. Such recognition entails more than just complex pattern matching. The approach presented within this paper uses specially built grammars to parse the C++ representation. The C++ representation is itself obtained using a modified version of the SAGE II C/C++ source code restructuring tool which is inturn based upon the Edison Design Group (EDG) C++ front-end. ROSETTA is a tool which automatically builds grammars and parsers from class definitions, associated parsers parse abstract syntax trees (ASTs) of lower level grammars into ASTs of higher level grammars. The …

Knowledge of an effective interatomic potential function underlies any effort to predict or rationalize the properties of solids and liquids. The experiments we undertake are directed towards determination of equilibrium and dynamic properties of simple fluids at densities sufficiently high that traditional computational methods and semi-empirical forms successful at ambient conditions may require reconsideration. In this paper we present high-pressure and temperature experimental sound speed data on a simple fluid, methanol. Impulsive Stimulated Light Scattering (ISLS) conducted on diamond-anvil cell (DAC) encapsulated samples offers an experimental approach to determine cross-pair potential interactions through equation of state determinations. In addition the kinetics of structural relaxation in fluids can be studied. We compare our experimental results with our thermochemical computational model Cheetah. Computational models are systematically improved with each addition of experimental data.

Hardware performance counters are CPU registers that count data loads and stores, cache misses, and other events. Counter data can help programmers understand software performance. Although CPUs typically have multiple counters, each can monitor only one type of event at a time, and some counters can monitor only certain events. Therefore, some CPUs cannot concurrently monitor interesting combinations of events. Software multiplexing partly overcomes this limitation by using time sharing to monitor multiple events on one counter: However; counter multiplexing is harder to implement for multithreaded programs than for single-threaded ones because of certain difficulties in managing the length of the time slices. This paper describes a software library called MPX that overcomes these difficulties. MPX allows applications to gather hardware counter data concurrently for any combination of countable events. MPX data are typically within a few percent of counts recorded without multiplexing.

SensIDA and IDA are general-purpose codes for solving differential-algebraic equation (DAE) initial value problems. SensIDA is a variant of IDA that includes options for simultaneously computing the DAE solution together with its first-=order sensitivity coefficients with respect to model parameters. SensIDA is written in ANSI-standard C and it is mainly based on IDA, DASPK3.0, and SensPVODE. IDA is based on DASPK2.0. DASPK3.0 is a Fortran77 code for the sensitivity analysis of DAE initial value problems. SensPVODE is a sensitivity analysis variant of the parallel ordinary differential equation solver PVODE. SensIDA can be compiled to run on serial or parallel computers. This is accomplished by specifying that the serial or parallel version of the vector module NVECTOR is used when compiling SensIDA. The parallel version of SensIDA uses MPI (Message-Passing Interface) to achieve parallelism, and is intended for a distributed Single Program Multiple Data environment in which all vectors are identically partitioned across processors. The idea is for each processor to solve a certain fixed subset of the DAEs that describe the model problem and the first-order sensitivity coefficients of the solution.

The energy required to ignite compressed deuterium-tritium fuel is a strong function of the fuel density. Through a series of detailed numerical simulations, peak fuel densities have been calculated as a function of the peak radiation drive temperature. Note that the time dependence of the radiation temperature (pulse shaping) has been optimized to obtain maximum density for each scaling point. A simple analytic scaling is developed, which agrees well with the numerical results. These scaling results are then used to obtain the required ignition energy as a function of peak drive temperature.

Newsletter of the Texas Department of Health discussing the news, activities, and events of the organization and other information related to health in Texas.

Some recent work has been done to look at improvements of transporting beam from the Lithium Lens to the Debuncher. This work has been done using the beamline modeling tools developed by Dave McGinnis. These tools, console application P143 and optimization code running MAD repeatedly on the Beam Physics UNIX system, were first used to match the Twiss and dispersion parameters at the end of AP2 to the Debuncher. Imaginary trims were then added to AP2 to study where additional trims could be used to help with beam control in small aperture areas.

Both ErbB1 and ErbB2 are overexpressed or amplified in breast tumors. To examine the effects of activating ErbB receptors in a context that mimics polarized epithelial cells in vivo, we activated ErbB1 and ErbB2 homodimers in preformed, growth-arrested mammary acini cultured in three-dimensional basement membrane gels. Activation of ErbB2, but not that of ErbB1, led to a reinitiation of cell proliferation and altered the properties of mammary acinar structures. These altered structures share several properties with early-stage tumors, including a loss of proliferative suppression, an absence of lumen, retention of the basement membrane and a lack of invasive properties. ErbB2 activation also disrupted tight junctions and the cell polarity of polarized epithelia, whereas ErbB1 activation did not have any effect. Our results indicate that ErbB receptors differ in their ability to induce early stages of mammary carcinogenesis in vitro and this three-dimensional model system can reveal biological activities of oncogenes that cannot be examined in vitro in standard transformation assays.

This document contains the CY 2001 schedules for the routine collection of samples for the Surface Environmental Surveillance Project (SESP) and Drinking Water Monitoring Project. Each section includes sampling locations, sample types, and analyses to be performed.

PNNL conducted a walk-through audit of Marine Corps Air Station at Camp Pendleton. The audit inspected a significant portion of the site and identified a large number of similar energy saving opportunities across all building types.

A test methodology for measuring temperature, impedance, pH, and electrochemical potential distributions within a sludge-packed tube support plate crevice in a laboratory test is described. The method successfully showed that there were large concentration gradients between the tube and tube support plate sides of the crevice. The testing also showed that strong bases concentrated more effectively than strong acids, and that the crevice pH, when exposed to seawater-based solutions, increased with increasing superheat and decreasing bulk concentration. The large variations in the crevice chemistry observed under heat transfer were eliminated upon shutdown. These new test data suggest that it might be beneficial to evaluate the variation in the extent of stress corrosion cracking with tube support plate elevation found in some steam generators in light of local chemistry changes, as well as the variation in tubing temperature. Because of the large crevice chemistry gradients during boiling heat transfer and their subsequent homogenization upon test shutdown, the results suggest reassessing the use of hideout return measurements and tube deposit analyses in industry to infer the crevice chemistry under heat transfer conditions.

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The objective of this calculation is to verify the energy balance of the thermal calculations analyzed by ANSYS Version (V) 5.4 solver (see Section 4). The scope of this calculation is limited to calculating the energy balance of a two-dimensional repository thermal representation using the temperatures obtained from ANSYS V5.4. The procedure, AP-3.124, Calculations (Ref. 3), and the Technical Work Plan for: Waste Package Design Description for LA (Ref. 2) are used to develop this calculation. The associated activity is the development of engineering evaluations to support the Licensing Application design activities.

The purpose of this Fire Hazards Analysis Technical Report (hereinafter referred to as Technical Report) is to assess the risk from fire within individual fire areas to ascertain whether the U.S. Department of Energy (DOE) fire safety objectives are met. The objectives, identified in DOE Order 420.1, Change 2, Fire Safety, Section 4.2, establish requirements for a comprehensive fire and related hazards protection program for facilities sufficient to minimize the potential for: (1) The occurrence of a fire or related event; (2) A fire that causes an unacceptable on-site or off-site release of hazardous or radiological material that will threaten the health and safety of the employees, the public, and the environment; (3) Vital DOE programs suffering unacceptable interruptions as a result of fire and related hazards; (4) Property losses from a fire and related events exceeding defined limits established by DOE; and (5) Critical process controls and safety class systems being damaged as a result of a fire and related event.