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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 1,261 records · Page 70
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

TiV_BCC_SolidSolution_128atoms_VASP6

We performed density functional theory (DFT) calculations for body-centered-cubic (BCC) structures with 128 lattices sites of solid solution binary alloys titanium-vanadium (Ti-V). The electronic structures of alloys have been calculated using Vienna Ab initio Simulation Package (VASP). Within this package the DFT approach is used to reduce many-body Schrodinger equation to set of single particle Kohn-Sham (KS) equations. The generalized electronic exchange-correlation functional is described by generalized gradient approximation with the Perdew-Burke-Ernzerhof parametrization. The electron-ion interactions is described by pseudopotentials developed within the plane-wave basis projector augmented-wave (PAW) approach. These pseudopotentials are available at the VASP portal (http://cms.mpi.univie.ac.at/vasp/). Our calculations have been run with the pseudopotentials treating s and p semi-core states as valence in case for the elements Ti and V. The electronic densities and potentials are expanded over plane-waves with energy cutoff of 350 eV. 2x2x2 k-mesh and normal precision were used. The alloys were modeled by supercell containing 128 randomly distributed atoms. At initial step the atoms occupy perfect bcc lattice cites. This initial structure was optimized until energy changes less than 1e-6 eV, while forces acting on atoms don't exceed 1e-2 eV/angstrom. The electron-ion interaction is described by PAW pseudopotentials. The calculations have been collected by sampling chemical compositions across the entire compositional range. The chemical compositions have been sampled by progressively changing the number of atoms per constituent by 4. For each chemical composition of binaries and ternaries, the first-principle calculations have been run for 100 randomized arrangements of the constituents on the BCC lattice sites. We collected data for a total of 3,100 randomized atomic structures over 31 chemical compositions. The calculations have been collected on Air Force HPC11 cluster using the VASP 6.5.1. Additional methodology and file structure information is available in the dataset README.txt file.

36 MATERIALS SCIENCE↗
DOE OSTI2026

NbTi_BCC_SolidSolution_128atoms_VASP6

We performed density functional theory (DFT) calculations for body-centered-cubic (BCC) structures with 128 lattices sites of solid solution binary alloys niobium-titanium (Nb-Ti). The electronic structures of alloys have been calculated using Vienna Ab initio Simulation Package (VASP), https://github.com/ORNL/ScalableWorkflow_VASP_Calculations. Within this package the DFT approach is used to reduce many-body Schrodinger equation to set of single particle Kohn-Sham (KS) equations. The generalized electronic exchange-correlation functional is described by generalized gradient approximation with the Perdew-Burke-Ernzerhof parametrization. The electron-ion interactions is described by pseudopotentials developed within the plane-wave basis projector augmented-wave (PAW) approach. These pseudopotentials are available at the VASP portal (http://cms.mpi.univie.ac.at/vasp/). Our calculations have been run with the pseudopotentials treating s and p semi-core states as valence in case for the elements Nb and Ti. The electronic densities and potentials are expanded over plane-waves with energy cutoff of 350 eV. 2x2x2 k-mesh and normal precision were used. The alloys were modeled by supercell containing 128 randomly distributed atoms. At initial step the atoms occupy perfect bcc lattice cites. This initial structure was optimized until energy changes less than 1e-6 eV, while forces acting on atoms don't exceed 1e-2 eV/angstrom. The electron-ion interaction is described by PAW pseudopotentials. The calculations have been collected by sampling chemical compositions across the entire compositional range. The chemical compositions have been sampled by progressively changing the number of atoms per constituent by 4. For each chemical composition of binaries and ternaries, the first-principle calculations have been run for 100 randomized arrangements of the constituents on the BCC lattice sites. We collected data for a total of 3,100 randomized atomic structures over 31 chemical compositions. The calculations have been collected on Air Force HPC11 cluster using the VASP 6.5.1. Additional methodology and file structure information is available in the dataset README.txt file.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Understanding Hydraulic Fracturing: A Multi-Scale Problem

Despite the impact that hydraulic fracturing has had on the energy sector, the physical mechanisms that control its efficiency and environmental impacts remain poorly understood in part because the length scales involved range from nano-meters to kilo-meters. We characterize flow and transport in shale formations across and between these scales using integrated computational, theoretical, and experimental efforts. At the field scale, we use discrete fracture network modeling to simulate production at a well site whose fracture network is based on a site characterization of a shale formation. At the core scale, we use triaxial fracture experiments and a finite-element discrete-element fracture propagation model with a coupled fluid solver to study dynamic crack propagation in low permeability shale. We use lattice Boltzmann pore-scale simulations and microfluidic experiments in both synthetic and real micromodels to study pore-scale flow phenomenon such as multiphase flow and mixing. A mechanistic description and integration of these multiple scales is required for accurate predictions of production and the eventual optimization of hydrocarbon extraction from unconventional reservoirs.

03 NATURAL GAS↗
DOE OSTI2019

A performance analysis of the first generation of HPC‐optimized Arm processors

Summary In this paper, we present performance results from Isambard, the first production supercomputer to be based on Arm CPUs that have been optimized specifically for HPC. Isambard is the first Cray XC50 “Scout” system, combining Cavium ThunderX2 Arm‐based CPUs with Cray's Aries interconnect. The full Isambard system will be delivered in the summer of 2018, when it will contain over 10 000 Arm cores. In this work, we present node‐level performance results from eight early‐access nodes that were upgraded to B0 beta silicon in March 2018. We present node‐level benchmark results comparing ThunderX2 with mainstream CPUs, including Intel Skylake and Broadwell, as well as Xeon Phi. We focus on a range of applications and mini‐apps important to the UK national HPC service, ARCHER, as well as to the Isambard project partners and the wider HPC community. We also compare performance across three major software toolchains available for Arm: Cray's CCE, Arm's version of Clang/Flang/LLVM, and GNU.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2018

Generalized 3D beam dynamics model for industrial traveling wave linacs design and simulations

Beam dynamics simulations in traveling wave (TW) accelerating structures with significant beam loading is a challenging problem. Some codes are capable of calculating the TW electromagnetic fields, and some can track particles through such fields, but most cannot treat both self-consistently. A few commercial codes can model the physics correctly at the expense of many processor-hour computations to obtain converged self-consistent solutions. However, simple, accurate equations of motion for intensive beam dynamics in TW accelerating structure analysis have been previously obtained by Masunov and subsequently implemented in the Hellweg code, which was developed at the Moscow Engineering-Physics Institute. Hellweg is based on equations that allow fast simulations of beam dynamics while taking into account such effects as beam loading, space charge, and external magnetic fields. In this paper, we describe in detail some recent improvements to the Hellweg physics kernel. We have generalized the Masunov results into a 3D set of equations of motion, which include all spatial components of the radiofrequency (RF) and external magnetic fields. We have also improved the Lapostolle space charge model to the general 3D ellipsoid form for any dimensions’ ratio, consideration for the particles outside the beam core, and the fields from the neighboring bunches that can exist in the real machine. These modifications allow approaching the Hellweg accuracy to the self-consistent commercial codes while keeping the simulation time short, which is essential during the linac design and optimization stage. The implementation of these new capabilities in Hellweg is carefully benchmarked against other codes and analytical calculations. The code is freely available with an open source license.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2018

Alkyl Chain End Group Engineering of Small Molecule Acceptors for Non-Fullerene Organic Solar Cells

Alkyl chain engineering is widely used to prepare high-performance donor materials. However, relatively few studies have been focused on the alkyl chain optimization of acceptor materials. Herein, a series of new A-D-A (acceptor-donor-acceptor) type small molecule acceptors (ITBTR-C2, ITBTR-C4, ITBTR-C6, and ITBTR-C8) with indacenodithieno[3,2-b]thiophene (IDTT) as the core, benzothiadiazole (BT) as the π bridge, and ethyl-, butyl-, hexyl-, and octyl-substituted 2-(1,1-dicyanomethylene) rhodanine as the end groups, respectively, are successfully synthesized to systematically investigate the alkyl substituent effects on the physical, chemical, and electronic properties of A-D-A type small molecule acceptors. All molecules exhibit a strong and broad absorption from 600 to 800 nm as well as similar HOMO and LUMO energy levels. ITBTR-C6 with hexyl substitution showed the highest electron mobility and better phase separation morphology after blending with a donor polymer (PBDB-T). Therefore, inverted bulk heterojunction organic solar cells based on ITBTR-C6:PBDB-T blends exhibit the highest power conversion efficiency (PCE) of 8.26% with an open-circuit voltage ( V OC ) of 0.89 V, a high short-circuit current density ( J SC ) of 15.80 mA/cm2, and a fill factor (FF) of 58.21%, while the PCEs of ITBTR-C2-, ITBTR-C4-, and ITBTR-C8-based devices are 7.04%, 7.43%, and 7.93%, respectively. After solvent vapor and thermal annealing, both the J SC and FF values of the ITBTR-C6-based device further increased, leading to a PCE of 9.29%. Furthermore, the results demonstrate that the alkyl chain substitution of A-D-A type small molecule acceptors is critical, and an appropriate adjustment of the alkyl chains can effectively enhance device performance.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2013

A nanoscale co-precipitation approach for property enhancement of Fe-base alloys

Precipitate size and number density are two key factors for tailoring the mechanical behavior of nanoscale precipitate-hardened alloys. However, during thermal aging, the precipitate size and number density change, leading to either poor strength or high strength but significantly reduced ductility. Here we demonstrate, by producing nanoscale co-precipitates in composition-optimized multicomponent precipitation-hardened alloys, a unique approach to improve the stability of the alloy against thermal aging and hence the mechanical properties. Our study provides compelling experimental evidence that these nanoscale co-precipitates consist of a Cu-enriched bcc core partially encased by a B2-ordered Ni(Mn, Al) phase. This co-precipitate provides a more complex obstacle for dislocation movement due to atomic ordering together with interphases, resulting in a high yield strength alloy without sacrificing alloy ductility.

36 MATERIALS SCIENCE↗
DOE OSTI2011

Scout: high-performance heterogeneous computing made simple

Researchers must often write their own simulation and analysis software. During this process they simultaneously confront both computational and scientific problems. Current strategies for aiding the generation of performance-oriented programs do not abstract the software development from the science. Furthermore, the problem is becoming increasingly complex and pressing with the continued development of many-core and heterogeneous (CPU-GPU) architectures. To acbieve high performance, scientists must expertly navigate both software and hardware. Co-design between computer scientists and research scientists can alleviate but not solve this problem. The science community requires better tools for developing, optimizing, and future-proofing codes, allowing scientists to focus on their research while still achieving high computational performance. Scout is a parallel programming language and extensible compiler framework targeting heterogeneous architectures. It provides the abstraction required to buffer scientists from the constantly-shifting details of hardware while still realizing higb-performance by encapsulating software and hardware optimization within a compiler framework.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2022

Analysis of Distributed Energy Storage as a Core Grid Infrastructure via Production Cost Modeling

Energy storage plays a pivotal role in enabling power system operation with more flexibility and resilience. Unlike current practice that considers energy storages as attached ancillary devices, this paper focuses on storages as a core infrastructure by looking at their spatial distribution in the system. A sensitivity analysis based on production cost modeling is conducted to demonstrate the benefits of distributed energy storages. First, the modeling of energy storages in production cost modeling is presented. Second, potential optimal locations of distributed energy storages in a power system are discussed. Finally, multiple scenarios with various numbers and locations of additional distributed energy storages in the WECC 2030 model are created. The production cost modeling results of these scenarios show that distributed energy storages have higher utilization compared to the centralized ES units and therefore provide significantly more benefits in terms of reduction in generation cost, emission cost, and volatility of location marginal prices. A saturation effect is observed suggesting the selection of optimal locations will further improve the benefits.

Nguyen, Quan H.↗
DOE OSTI2014

Scintillation Properties of a Cs2LiLa(Br6)90%(Cl6)10%:Ce (CLLBC) Crystal

In investigations of Ce3+-doped Cs2LiLa(Br6)90%(Cl6)10% (CLLBC) elpasolite crystals, the crystals show an excellent neutron and gamma (n/g) radiation response. The results of our studies on the scintillation properties of CLLBC viz. radioluminescence, energy resolution, light yield, decay times, and nonproportionality are discussed. The CLLBC detector can provide energy resolution as good as 4.1% at 662 keV (FWHM), which is better than that of NaI:Tl. Because the crystal contains 6Li, CLLBC can also detect thermal neutrons. In the energy spectra, the full energy thermal neutron peak appears near or above 3 MeV gamma equivalent energy. This high-energy signature for the thermal neutron peak means that very effective pulse height discrimination is possible. Unfortunately, because the core-to-valence luminescence observed in other elpasolites that can be exploited for effective pulse shape discrimination (PSD) is not observed in the CLLBC, other strategies for obtaining the PSD of CLLBC are needed. The n/g discrimination capability of CLLBC detectors may be optimized by tuning the cerium doping content for maximum effect on n/g pulse shape differences. The value of adding a chlorine component to the nominal CLLB crystal is discussed. Because the crystal contains chlorine, its sensitivity to fast neutrons is better than that of Cs2LiLaBr6 (CLLB). Further, an array of three of these CLLBC detectors may be able to perform directional detection in both the neutron and gamma channels simultaneously.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Low-Cost, Scalable Sorbents with Balanced Capacity-Kinetics-Thermodynamics for H2 Storage

The goal of this project is to utilize cutting-edge materials science, chemistry, and process engineering to demonstrate the feasibility of a new class of scalable sorbents with unprecedented balance of capacity-kinetics-thermodynamics for H 2 storage in fossil fuel power plants . The core fabrication leverages the unique exotic properties (e.g., high H 2 affinity, ultrahigh surface area, and exceptional thermal, mechanical and chemical stability) of the emerging 2D materials i.e. hexagonal boron nitride (hBN) followed by strategic coupling with alkali metals (Li, Na) dopants and optimal interlayer distance to deliver a stable, long-term energy storage for the grid. Figure 1 shows how this technology works.

08 HYDROGEN↗
DOE OSTI2012

Lessons Learned from a Complex FUSRAP Site - Sylvania Corning FUSRAP Site - 12269

Since its addition to the Formerly Utilized Sites Remedial Action Program (FUSRAP) in 2005, the Sylvania Corning FUSRAP Site (the Site) in Hicksville, New York, has provided challenges and opportunities from which to gain lessons learned for conducting investigation work at a complex multi-contaminant FUSRAP Site. The United States Army Corps of Engineers (USACE) and its contractors conducted a Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) Remedial Investigation (RI) and are currently in the Feasibility Study (FS) phase at the Site. This paper presents the planning, execution, and reporting lessons learned by USACE during the RI/FS. The Site, operated from 1952 to 1967 for the research, development, and fabrication of nuclear elements under the Atomic Energy Commission, and other government and commercial contracts. Previous investigations performed by the New York State Department of Environmental Conservation (NYSDEC) and the current property owner have identified uranium, thorium, nickel, and chlorinated solvents, as Site contaminants [1]. The property owner is currently under two separate voluntary agreements with NYSDEC to investigate and remediate the Site. USACE's work at the site has been independent of this voluntary agreement and has moved on a parallel path with any work the property owner has completed. The project at the Site is complex because of the radiological and chemical concerns in both soils and groundwater, high hydraulically conductive soils, lack of a shallow aquiclude/aquitard, and a principal water table aquifer underlying the site. Contaminants are migrating from the Site and may potentially impact local drinking water supplies (municipal wells). During the RI/FS process the project team has encountered many issues and has thus developed many resolutions. The issues are organized into three categories: Planning and Contracting, Execution, and Reporting. Planning and Contracting lessons learned include: how to incorporate an overwhelming volume of historical data; how to manage a complex team of three prime contractors innovatively, and how to implement a project under an Award Fee task order. Execution lessons learned include: characterization of investigation derived wastes, and proper approach to radiological scanning of direct-push borings and soil cores. Reporting lessons learned include: coordinating multiple phase (iterative) reporting, large dataset presentation, and the National Priorities List (NPL) designation. The goal of this paper is to provide a resource for other project delivery teams that encounter similar situations on their projects to optimize cost savings, realization of efficiency, shorten schedules, or simply ensure higher quality deliverables. Each FUSRAP project is unique but there are many lessons we can apply to each site to gain efficiency and work more effectively. The Sylvania Corning FUSRAP site is a complex site with both soils and groundwater contamination, contamination to depths of 182 meters, and a highly politically charged environment of PRP involvement. Many of the lessons the project team has learned during the life of the project to date are being shared with others as well as being applied back to this project for future work. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2010

Natural Circulation Level Optimization and the Effect during ULOF Accident in the SPINNOR Reactors

Natural circulation level optimization and the effect during loss of flow accident in the 250 MWt MOX fuelled small Pb-Bi Cooled non-refueling nuclear reactors (SPINNOR) have been performed. The simulation was performed using FI-ITB safety code which has been developed in ITB. The simulation begins with steady state calculation of neutron flux, power distribution and temperature distribution across the core, hot pool and cool pool, and also steam generator. When the accident is started due to the loss of pumping power the power distribution and the temperature distribution of core, hot pool and cool pool, and steam generator change. Then the feedback reactivity calculation is conducted, followed by kinetic calculation. The process is repeated until the optimum power distribution is achieved. The results show that the SPINNOR reactor has inherent safety capability against this accident.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2011

Quantum Monte Carlo Endstation for Petascale Computing

NCSU research group has been focused on accomplising the key goals of this initiative: establishing new generation of quantum Monte Carlo (QMC) computational tools as a part of Endstation petaflop initiative for use at the DOE ORNL computational facilities and for use by computational electronic structure community at large; carrying out high accuracy quantum Monte Carlo demonstration projects in application of these tools to the forefront electronic structure problems in molecular and solid systems; expanding the impact of QMC methods and approaches; explaining and enhancing the impact of these advanced computational approaches. In particular, we have developed quantum Monte Carlo code (QWalk, www.qwalk.org) which was significantly expanded and optimized using funds from this support and at present became an actively used tool in the petascale regime by ORNL researchers and beyond. These developments have been built upon efforts undertaken by the PI's group and collaborators over the period of the last decade. The code was optimized and tested extensively on a number of parallel architectures including petaflop ORNL Jaguar machine. We have developed and redesigned a number of code modules such as evaluation of wave functions and orbitals, calculations of pfaffians and introduction of backflow coordinates together with overall organization of the code and random walker distribution over multicore architectures. We have addressed several bottlenecks such as load balancing and verified efficiency and accuracy of the calculations with the other groups of the Endstation team. The QWalk package contains about 50,000 lines of high quality object-oriented C++ and includes also interfaces to data files from other conventional electronic structure codes such as Gamess, Gaussian, Crystal and others. This grant supported PI for one month during summers, a full-time postdoc and partially three graduate students over the period of the grant duration, it has resulted in 13 published papers, 15 invited talks and lectures nationally and internationally. My former graduate student and postdoc Dr. Michal Bajdich, who was supported byt this grant, is currently a postdoc with ORNL in the group of Dr. F. Reboredo and Dr. P. Kent and is using the developed tools in a number of DOE projects. The QWalk package has become a truly important research tool used by the electronic structure community and has attracted several new developers in other research groups. Our tools use several types of correlated wavefunction approaches, variational, diffusion and reptation methods, large-scale optimization methods for wavefunctions and enables to calculate energy differences such as cohesion, electronic gaps, but also densities and other properties, using multiple runs one can obtain equations of state for given structures and beyond. Our codes use efficient numerical and Monte Carlo strategies (high accuracy numerical orbitals, multi-reference wave functions, highly accurate correlation factors, pairing orbitals, force biased and correlated sampling Monte Carlo), are robustly parallelized and enable to run on tens of thousands cores very efficiently. Our demonstration applications were focused on the challenging research problems in several fields of materials science such as transition metal solids. We note that our study of FeO solid was the first QMC calculation of transition metal oxides at high pressures.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

Quantum Yields, Surface Quenching, and Passivation Efficiency for Ultrasmall Core/Shell Upconverting Nanoparticles

We synthesized and characterized a set of ultrasmall hexagonal-phase NaGdF 4 : 20% Yb 3+ , 2% Er 3+ upconversion nanoparticles with core diameters of 3.7 ± 0.5 nm. In order to assess passivation effects and the influence of possible core-shell intermixing and to identify optimum particle structures for combined imaging in the visible and near-infrared (vis-NIR: 410-850 nm) and short-wave infrared (SWIR: 1520 nm), NaYF 4 shells of varying thicknesses (monolayer to 10 nm) were introduced and the influence of this parameter on the upconversion and downshifting photoluminescence of these particles was studied at different excitation power densities. This included excitation power-dependent emission spectra, slope factors, quantum yields, and excited state decay kinetics. These measurements demonstrated enhancement factors of the upconversion quantum yield of >10 000 in the low power region and an excitation power density-independent quantum yield of the downshifted emission at 1520 nm between 0.1 and 14%. The optimized shell thickness for combined vis and SWIR imaging was identified as 5 nm. Furthermore, lifetimes and quantum yields can be continuously tuned by shell thickness which can be exploited for lifetime multiplexing and encoding. The fact that we did not observe a saturation of the upconversion quantum yield or the excited state decay kinetics with increasing shell thickness is ascribed to a strong intermixing of the active core with the inert shell during the shelling procedure. This implies the potential of spectroscopic tools to detect cation intermixing.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Theory Guided Fine‐Tune of Strain Effects in Pt Ternary Alloy via Rare Earth Templating: Achieving High Performance PEMFCs Catalysts

The sluggish kinetics and insufficient durability of platinum-based catalysts remain crucial barriers limiting proton-exchange-membrane fuel cells (PEMFCs) deployment. Here, we report a theory-guided synthesis combined with rare-earth templating to realize a previously inaccessible Pt 5 Co-like phase with tailored atomic-scale strain. Guided by density functional theory (DFT) calculations, we identified that a Pt 5 Co-like sublayer can induce a unique mild compressive strain (−1.24%) to the Pt(111) shell and an optimal *OH binding energy shift (ΔE ≈ 0.11 eV). This shift positions the alloy catalyst near the apex of the oxygen reduction reaction activity volcano. This prediction guided the synthesis of ternary alloy Pt 5 (Ce)Co@Pt multilayer nanoparticles, featuring a Ce-stabilized core, a Pt 5 Co-like sublayer, and a Pt-rich shell. This catalyst demonstrates both exceptionally high activity and durability, achieving a mass activity of 2.6 A∙mg Pt −1 in rotating disk electrode testing. In fuel cell membrane electrode assembly tests, Pt 5 (Ce)Co@Pt achieves a current density of 1.9 A∙cm −2 at 0.7 V under heavy-duty vehicle conditions. Remarkably, it maintains 1.2 A∙cm −2 after 1 80 000 AST cycles, doubling the U.S. DOE 2025 target. This work demonstrates a rational design strategy that DFT-guided strain engineering integrates with rare-earth templating to advance Pt-based catalysts for fuel cell applications.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2016

Large-scale optimization-based non-negative computational framework for diffusion equations: Parallel implementation and performance studies

It is well-known that the standard Galerkin formulation, which is often the formulation of choice under the finite element method for solving self-adjoint diffusion equations, does not meet maximum principles and the non-negative constraint for anisotropic diffusion equations. Recently, optimization-based methodologies that satisfy maximum principles and the non-negative constraint for steady-state and transient diffusion-type equations have been proposed. To date, these methodologies have been tested only on small-scale academic problems. The purpose of this paper is to systematically study the performance of the non-negative methodology in the context of high performance computing (HPC). PETSc and TAO libraries are, respectively, used for the parallel environment and optimization solvers. For large-scale problems, it is important for computational scientists to understand the computational performance of current algorithms available in these scientific libraries. The numerical experiments are conducted on the state-of-the-art HPC systems, and a single-core performance model is used to better characterize the efficiency of the solvers. Furthermore, our studies indicate that the proposed non-negative computational framework for diffusion-type equations exhibits excellent strong scaling for real-world large-scale problems.

97 MATHEMATICS AND COMPUTING↗