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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,531 records · Page 85
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

SU-F-J-72: A Clinical Usable Integrated Contouring Quality Evaluation Software for Radiotherapy

Purpose: To introduce the Auto Contour Evaluation (ACE) software, which is the clinical usable, user friendly, efficient and all-in-one toolbox for automatically identify common contouring errors in radiotherapy treatment planning using supervised machine learning techniques. Methods: ACE is developed with C# using Microsoft .Net framework and Windows Presentation Foundation (WPF) for elegant GUI design and smooth GUI transition animations through the integration of graphics engines and high dots per inch (DPI) settings on modern high resolution monitors. The industrial standard software design pattern, Model-View-ViewModel (MVVM) pattern, is chosen to be the major architecture of ACE for neat coding structure, deep modularization, easy maintainability and seamless communication with other clinical software. ACE consists of 1) a patient data importing module integrated with clinical patient database server, 2) a 2D DICOM image and RT structure simultaneously displaying module, 3) a 3D RT structure visualization module using Visualization Toolkit or VTK library and 4) a contour evaluation module using supervised pattern recognition algorithms to detect contouring errors and display detection results. ACE relies on supervised learning algorithms to handle all image processing and data processing jobs. Implementations of related algorithms are powered by Accord.Net scientific computing library for better efficiency and effectiveness. Results: ACE can take patient’s CT images and RT structures from commercial treatment planning software via direct user input or from patients’ database. All functionalities including 2D and 3D image visualization and RT contours error detection have been demonstrated with real clinical patient cases. Conclusion: ACE implements supervised learning algorithms and combines image processing and graphical visualization modules for RT contours verification. ACE has great potential for automated radiotherapy contouring quality verification. Structured with MVVM pattern, it is highly maintainable and extensible, and support smooth connections with other clinical software tools.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2011

Yield Of Radioactive Products Of Transfer Reactions Induced By {sup 6}He Ions On {sup 197}Au Target

The excitation functions and isomeric cross section ratios of Tl isotopes obtained at irradiation of {sup 197}Au by a {sup 6}He-ions beams with energies from 15 to 60 MeV are analyzed. The EMPIRE-2.18 code which takes into account the branching ratios of gamma-transitions of discrete gamma-cascade in a residual nucleus in the calculations of the cross sections of the isomeric and ground nuclear states production is used.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2010

Xyce parallel electronic simulator design.

This document is the Xyce Circuit Simulator developer guide. Xyce has been designed from the 'ground up' to be a SPICE-compatible, distributed memory parallel circuit simulator. While it is in many respects a research code, Xyce is intended to be a production simulator. As such, having software quality engineering (SQE) procedures in place to insure a high level of code quality and robustness are essential. Version control, issue tracking customer support, C++ style guildlines and the Xyce release process are all described. The Xyce Parallel Electronic Simulator has been under development at Sandia since 1999. Historically, Xyce has mostly been funded by ASC, the original focus of Xyce development has primarily been related to circuits for nuclear weapons. However, this has not been the only focus and it is expected that the project will diversify. Like many ASC projects, Xyce is a group development effort, which involves a number of researchers, engineers, scientists, mathmaticians and computer scientists. In addition to diversity of background, it is to be expected on long term projects for there to be a certain amount of staff turnover, as people move on to different projects. As a result, it is very important that the project maintain high software quality standards. The point of this document is to formally document a number of the software quality practices followed by the Xyce team in one place. Also, it is hoped that this document will be a good source of information for new developers.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2019

Electron transfer in extended systems: characterization by periodic density functional theory including the electronic coupling

In this paper, we describe a new computer implementation of electron transfer (ET) theory in extended systems treated by periodic density functional theory (DFT), including the calculation of the electronic coupling transition element V AB . In particular, the development opens up the full characterization of electron transfer in the solid state. The approach is valid for any single-determinant wavefunction with localized character representing the electronic structure of the system, from Hartree–Fock (HF) theory, to density functional theory (DFT), hybrid DFT theory, DFT+U theory, and constrained DFT (cDFT) theory. The implementation in CP2K reuses the high-performance functions of the code. The computational cost is equivalent to only one iteration of an HF calculation. We present test calculations for electron transfer in a number of systems, including a 1D-model of ferric oxide, hematite Fe2O 3 , rutile TiO 2 , and finally bismuth vanadate BiVO 4 .

14 SOLAR ENERGY↗
DOE OSTI2012

Validation of a plant dynamics code for 4S - Test analysis of natural circulation behavior

A plant transient dynamics code for a sodium-cooled fast reactor was developed by Toshiba. The code is used to evaluate the safety performance of Super-Safe, Small, and Simple reactor (4S) for Anticipated Operational Occurrences (AOOs), Design Basis Accident (DBA) and Beyond DBA (BDBA). The code is currently undergoing verification and validation (V and V). As one of the validation, test analysis of the Shutdown Heat Removal Test (SHRT)-17 performed in the Experimental Breeder Reactor (EBR)-II was conducted. The SHRT-17 is protected loss of flow test. The purpose of this validation is to confirm capability of the code to simulate natural circulation behavior of the plant. As a result, good agreements are shown between the analytical results and the measured data which were available from instrumented subassembly. The detailed validation result of the natural circulation behavior is described in this paper. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2014

RADIATION TRANSPORT FOR EXPLOSIVE OUTFLOWS: OPACITY REGROUPING

Implicit Monte Carlo (IMC) and Discrete Diffusion Monte Carlo (DDMC) are methods used to stochastically solve the radiative transport and diffusion equations, respectively. These methods combine into a hybrid transport-diffusion method we refer to as IMC-DDMC. We explore a multigroup IMC-DDMC scheme that in DDMC, combines frequency groups with sufficient optical thickness. We term this procedure ''opacity regrouping''. Opacity regrouping has previously been applied to IMC-DDMC calculations for problems in which the dependence of the opacity on frequency is monotonic. We generalize opacity regrouping to non-contiguous groups and implement this in SuperNu, a code designed to do radiation transport in high-velocity outflows with non-monotonic opacities. We find that regrouping of non-contiguous opacity groups generally improves the speed of IMC-DDMC radiation transport. We present an asymptotic analysis that informs the nature of the Doppler shift in DDMC groups and summarize the derivation of the Gentile-Fleck factor for modified IMC-DDMC. We test SuperNu using numerical experiments including a quasi-manufactured analytic solution, a simple 10 group problem, and the W7 problem for Type Ia supernovae. We find that opacity regrouping is necessary to make our IMC-DDMC implementation feasible for the W7 problem and possibly Type Ia supernova simulations in general. We compare the bolometric light curves and spectra produced by the SuperNu and PHOENIX radiation transport codes for the W7 problem. The overall shape of the bolometric light curves are in good agreement, as are the spectra and their evolution with time. However, for the numerical specifications we considered, we find that the peak luminosity of the light curve calculated using SuperNu is ∼10% less than that calculated using PHOENIX.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

Code Verification Capabilities and Assessments in Support of ASC V&V Level 2 Milestone #6035

This document provides a summary of the code verification activities supporting the FY17 Level 2 V&V milestone entitled “Deliver a Capability for V&V Assessments of Code Implementations of Physics Models and Numerical Algorithms in Support of Future Predictive Capability Framework Pegposts.” The physics validation activities supporting this milestone are documented separately. The objectives of this portion of the milestone are: 1) Develop software tools to support code verification analysis; 2) Document standard definitions of code verification test problems; and 3) Perform code verification assessments (focusing on error behavior of algorithms). This report and a set of additional standalone documents serve as the compilation of results demonstrating accomplishment of these objectives.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2015

Verification of Monte Carlo transport codes against measured small angle p-, d-, and t-emission in carbon fragmentation at 600 MeV/nucleon

Momentum spectra of hydrogen isotopes have been measured at 3.5° from 12 C fragmentation on a Be target. Momentum spectra cover both the region of fragmentation maximum and the cumulative region. Differential cross sections span five orders of magnitude. The data are compared to predictions of four Monte Carlo codes: QMD, LAQGSM, BC, and INCL++. There are large differences between the data and predictions of some models in the high momentum region. The INCL++ code gives the best and almost perfect description of the data.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2018

Influence of Magnetically Conjugate Fragments of Auroral Emission Images on the Accuracy of Determining E{sub av} of Precipitating Electrons

Results of magnetic conjugation of image fragments of auroral emissions at different altitudes along the magnetic field lines and preliminary results of evaluation of their influence on the accuracy of remote mapping of energy characteristics of precipitating electrons are presented. The results are obtained using the code of tracing being an integral part of the software Vector M intended for calculation of accompanying, geophysical, and astronomical information for the center of mass of a space vehicle (SV) and remote observation of aurora by means of Aurovisor-VIS/MP imager onboard the SV Meteor-MP to be launched.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

Calculation of electron-impact rotationally elastic total cross sections for NH{sub 3}, H{sub 2}S, and PH{sub 3} over the energy range from 0.01 eV to 2 keV

This paper report results of calculation of the total cross section Q{sub T} for electron impact on NH{sub 3}, H{sub 2}S, and PH{sub 3} over a wide range of incident energies from 0.01 eV to 2 keV. Total cross sections Q{sub T} (elastic plus electronic excitation) for incident energies below the ionization threshold of the target were calculated using the UK molecular R-matrix code through the Quantemol-N software package and cross sections at higher energies were derived using the spherical complex optical potential formalism. The two methods are found to give self-consistent values where they overlap. The present results are, in general, found to be in good agreement with previous experimental and theoretical results.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2011

Facility Targeting, Protection and Mission Decision Making Using the VISAC Code

The Visual Interactive Site Analysis Code (VISAC) is a Java-based graphical expert system developed by ORNL for the Defense Threat Reduction Agency, Nuclear Regulatory Commission (NRC) and other sponsors to aid in targeting facilities and to predict the associated collateral effects for the go, no go mission decision making process. VISAC integrates the three concepts of target geometric modeling, damage assessment capabilities, and an event/fault tree methodology for evaluating accident/incident consequences. It can analyze a variety of accidents/incidents at nuclear or industrial facilities, ranging from simple component sabotage to an attack with military or terroist weapons. For nuclear facilities, VISAC predicts the facility damage, estimated downtime, amount and timing of any radionuclides released. used in conunction with DTRA's HPAC code, VISAC also can analyze transport and dispersion of the radionuclides, levels of contamination of the surrounding area, and the population at risk. VISAC has also been used by the NRC to aid in the development of protective measures for nuclear facilities that may be subjected to attacks by car/truck bombs.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2012

Spent fuel pool analysis using TRACE code

The storage requirements of Spent Fuel Pools have been analyzed with the purpose to increase their rack capacities. In the past, the thermal limits have been mainly evaluated with conservative codes developed for this purpose, although some works can be found in which a best estimate code is used. The use of best estimate codes is interesting as they provide more realistic calculations and they have the capability of analyzing a wide range of transients that could affect the Spent Fuel Pool. Two of the most representative thermal-hydraulic codes are RELAP-5 and TRAC. Nowadays, TRACE code is being developed to make use of the more favorable characteristics of RELAP-5 and TRAC codes. Among the components coded in TRACE that can be used to construct the model, it is interesting to use the VESSEL component, which has the capacity of reproducing three dimensional phenomena. In this work, a thermal-hydraulic model of the Maine Yankee spent fuel pool using the TRACE code is developed. Such model has been used to perform a licensing calculation and the results obtained have been compared with experimental measurements made at the pool, showing a good agreement between the calculations predicted by TRACE and the experimental data. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2014

Software Quality Metrics for Geant4: An Initial Assessment - Paper 122

In the context of critical applications, such as shielding and radiation protection, ensuring the quality of simulation software they depend on is of utmost importance. The assessment of simulation software quality is crucial both to determine its adoption in experimental applications and to guarantee reproducibility of outcome over time. Geant4 is a simulation system used in a wide range of experimental applications, some of which, such as radiation protection and biomedical studies, may involve critical use cases and would especially profit from an objective assessment of the software quality. In this study, we present the first results from an ongoing analysis of Geant4 code based on established software metrics from the perspective of software engineering. The analysis evaluates the current status of the code to quantify its characteristics with respect to documented quality standards; further appraisals concern evolutions over a series of release distributions. The quantitative assessment of the software is initially focused on a subset of Geant4 packages, which play a key role in scientific applications and are representative of different software development processes. We describe the chosen software metrics that map the entities of a software system to numeric values through mathematical definitions, quantifying software attributes ranging from functionality to maintainability. To measure such metrics, we exploited a set of software metrics tools, i.e. programs that implement a set of software metrics definitions. They allow software engineers to assess a software system by extracting the required attributes from the software and providing the corresponding metric values. To correlate software metrics values in a well-defined way, we used software quality standard models, such as the ISO/IEC 9126 standard, which aggregate numerical values to aid quality analysis and assessment. With this work we aim to create a baseline for evaluating correlations between software quality embedded in the Geant4 development process and simulation observables produced by Geant4-based applications. Furthermore, we intend to highlight what metrics are most effective at evaluating radiation transport software quality. We are confident that the result will provide constructive guidance both to improve key software tools, such as Geant4, and to estimate their contribution in risk analysis concerning sensitive applications. The remainder of this paper is structured as follows. We first discuss the approach adopted to fulfil our assessment. Then, we present the setup of our experiments and the way we collected data. We provide an initial interpretation of a subset of data resulting from measurements made on the selected Geant4 packages. As the analysis is still ongoing at the time of submitting this abstract, some results will be documented in the final paper and in the conference presentation. With this work we aim to create a proper Geant4 data set for evaluating its software characteristics and identifying both strengths and weaknesses. In this initial study, we considered the geometry and processes packages, which play a major role in most simulation applications. The data analysis is in progress at the time of writing; its complexity is related to the differences among software metrics tools, to the large amount of data to be evaluated and to the pioneering character of this project. We are confident that the results will provide valuable indications for the Geant4 user community and constructive guidance to improve key Geant4 packages. Other Monte Carlo codes could profit from the methodology developed in this pilot project for similar assessments of their software quality. At the end of this study, we intend to create a baseline for evaluating correlations between software quality embedded in the Geant4 development process and simulation observables produced by Geant4-based applications. (authors)

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2018

Modelling an induced thermal plume with data from electrical resistivity tomography and distributed temperature sensing: a case study in northeast Italy

Groundwater tracer tests are often used to improve aquifer characterization, but they present several disadvantages, such as the need to pour solutions or dyes into the aquifer system and alteration of the water’s chemical properties. Thus, tracers can affect the groundwater flow mechanics and data interpretation becomes more complex, hindering effective study of ground heat pumps for low enthalpy geothermal systems. This paper presents a preliminary methodology based on a multidisciplinary application of heat as a tracer for defining the main parameters of shallow aquifers. The field monitoring techniques electrical resistivity tomography (ERT) and distributed temperature sensing (DTS) are noninvasive and were applied to a shallow-aquifer test site in northeast Italy. The combination of these measurement techniques supports the definition of the main aquifer parameters and therefore the construction of a reliable conceptual model, which is then described through the numerical code FEFLOW. This model is calibrated with DTS and validated by ERT outcomes. The reliability of the numerical model in terms of fate and transport is thereby enhanced, leading to the potential for better environmental management and protection of groundwater resources through more cost-effective solutions.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

SU-F-T-367: Using PRIMO, a PENELOPE-Based Software, to Improve the Small Field Dosimetry of Linear Accelerators

Purpose: To calculate output correction factors for Varian Clinac 2100iX beams for seven small field detectors and use the values to determine the small field output factors for the linacs at Karolinska university hospital. Methods: Phase space files (psf) for square fields between 0.25cm and 10cm were calculated using the PENELOPE-based PRIMO software. The linac MC-model was tuned by comparing PRIMO-estimated and experimentally determined depth doses and lateral dose-profiles for 40cmx40cm fields. The calculated psf were used as radiation sources to calculate the correction factors of IBA and PTW detectors with the code penEasy/PENELOPE. Results: The optimal tuning parameters of the MClinac model in PRIMO were 5.4 MeV incident electron energy and zero energy spread, focal spot size and beam divergence. Correction factors obtained for the liquid ion chamber (PTW-T31018) are within 1% down to 0.5 cm fields. For unshielded diodes (IBA-EFD, IBA-SFD, PTW-T60017 and PTW-T60018) the corrections are up to 2% at intermediate fields (>1cm side), becoming down to −11% for fields smaller than 1cm. The shielded diode (IBA-PFD and PTW-T60016) corrections vary with field size from 0 to −4%. Volume averaging effects are found for most detectors in the presence of 0.25cm fields. Conclusion: Good agreement was found between correction factors based on PRIMO-generated psf and those from other publications. The calculated factors will be implemented in output factor measurements (using several detectors) in the clinic. PRIMO is a userfriendly general code capable of generating small field psf and can be used without having to code own linac geometries. It can therefore be used to improve the clinical dosimetry, especially in the commissioning of linear accelerators. Important dosimetry data, such as dose-profiles and output factors can be determined more accurately for a specific machine, geometry and setup by using PRIMO and having a MC-model of the detector used.

43 PARTICLE ACCELERATORS↗
DOE OSTI2014

Collaborating CPU and GPU for large-scale high-order CFD simulations with complex grids on the TianHe-1A supercomputer

Programming and optimizing complex, real-world CFD codes on current many-core accelerated HPC systems is very challenging, especially when collaborating CPUs and accelerators to fully tap the potential of heterogeneous systems. In this paper, with a tri-level hybrid and heterogeneous programming model using MPI + OpenMP + CUDA, we port and optimize our high-order multi-block structured CFD software HOSTA on the GPU-accelerated TianHe-1A supercomputer. HOSTA adopts two self-developed high-order compact definite difference schemes WCNS and HDCS that can simulate flows with complex geometries. We present a dual-level parallelization scheme for efficient multi-block computation on GPUs and perform particular kernel optimizations for high-order CFD schemes. The GPU-only approach achieves a speedup of about 1.3 when comparing one Tesla M2050 GPU with two Xeon X5670 CPUs. To achieve a greater speedup, we collaborate CPU and GPU for HOSTA instead of using a naive GPU-only approach. We present a novel scheme to balance the loads between the store-poor GPU and the store-rich CPU. Taking CPU and GPU load balance into account, we improve the maximum simulation problem size per TianHe-1A node for HOSTA by 2.3×, meanwhile the collaborative approach can improve the performance by around 45% compared to the GPU-only approach. Further, to scale HOSTA on TianHe-1A, we propose a gather/scatter optimization to minimize PCI-e data transfer times for ghost and singularity data of 3D grid blocks, and overlap the collaborative computation and communication as far as possible using some advanced CUDA and MPI features. Scalability tests show that HOSTA can achieve a parallel efficiency of above 60% on 1024 TianHe-1A nodes. With our method, we have successfully simulated an EET high-lift airfoil configuration containing 800M cells and China's large civil airplane configuration containing 150M cells. To our best knowledge, those are the largest-scale CPU–GPU collaborative simulations that solve realistic CFD problems with both complex configurations and high-order schemes.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

SAPHIRE 8 Quality Assurance Software Metrics Report

The purpose of this review of software metrics is to examine the quality of the metrics gathered in the 2010 IV&V and to set an outline for results of updated metrics runs to be performed. We find from the review that the maintenance of accepted quality standards presented in the SAPHIRE 8 initial Independent Verification and Validation (IV&V) of April, 2010 is most easily achieved by continuing to utilize the tools used in that effort while adding a metric of bug tracking and resolution. Recommendations from the final IV&V were to continue periodic measurable metrics such as McCabe's complexity measure to ensure quality is maintained. The four software tools used to measure quality in the IV&V were CodeHealer, Coverage Validator, Memory Validator, Performance Validator, and Thread Validator. These are evaluated based on their capabilities. We attempted to run their latest revisions with the newer Delphi 2010 based SAPHIRE 8 code that has been developed and was successful with all of the Validator series of tools on small tests. Another recommendation from the IV&V was to incorporate a bug tracking and resolution metric. To improve our capability of producing this metric, we integrated our current web reporting system with the SpiraTest test management software purchased earlier this year to track requirements traceability.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2012

Condensation model for the ESBWR passive condensers

In the General Electric's Economic simplified boiling water reactor (GE-ESBWR) the passive containment cooling system (PCCS) plays a major role in containment pressure control in case of an loss of coolant accident. The PCCS condenser must be able to remove sufficient energy from the reactor containment to prevent containment from exceeding its design pressure following a design basis accident. There are three PCCS condensation modes depending on the containment pressurization due to coolant discharge; complete condensation, cyclic venting and flow through mode. The present work reviews the models and presents model predictive capability along with comparison with existing data from separate effects test. The condensation models in thermal hydraulics code RELAP5 are also assessed to examine its application to various flow modes of condensation. The default model in the code predicts complete condensation well, and basically is Nusselt solution. The UCB model predicts through flow well. None of condensation model in RELAP5 predict complete condensation, cyclic venting, and through flow condensation consistently. New condensation correlations are given that accurately predict all three modes of PCCS condensation. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗