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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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All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

The DevOps : a concise understanding to the DevOps philosophy and science

This writing examines the DevOps practice from a new perspective, one of understanding its philosophical and scientific nature. DevOps has fundamentally changed the landscape for research and development based on guiding philosophical and scientific principles. Advanced computational technologies and domains have adopted DevOps to enable advanced solution engineering for efficient, quality-assured output. The author provides a concise account of how the philosophy and science of DevOps synergistically defines its essential disposition.

42 ENGINEERING↗
DOE OSTI2021

Energy Storage in South Asia: Understanding the Role of Grid-Connected Energy Storage in South Asia’s Power Sector Transformation

During the last decade, the cost of energy storage technologies, primarily lithium-ion battery energy storage systems (BESS), has declined rapidly and is projected to decline further over the next decade. This study provides a first-of-its-kind assessment of cost-effective opportunities for grid-scale energy storage deployment in South Asia both in the near term and the long term, including a detailed analysis of energy storage drivers, potential barriers, and the role of energy storage in system operations. We conduct scenarios-based capacity expansion modeling to assess when, where and how much energy storage can be cost-effectively deployed in India through 2050. The analysis relies on state-of-the-art modeling approaches to uncover and compare the value streams of battery storage with different durations as well as pumped storage hydropower. We also run hourly simulations of system operations in 2030 and 2050 to understand how energy storage will be utilized by system operators to help integrate RE and reduce operating costs. For Bangladesh, Bhutan, and Nepal, we use operational simulations to explore how increasing deployment of energy storage can help optimize the use of domestic resources and cross-border electricity trade.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2021

Understanding Discrete Fracture Networks Through Spectral Graph Theory

Discrete Fracture Network models (DFNs) are used to simulate fluid flow and particle transport through fracture networks in low permeability rock. Understanding these processes are essential in many subsurface applications, such as environmental restoration of contaminated fractured media, CO 2 sequestration, detection of low-level nuclear tests, and hydrocarbon extraction. Compared with other models, DFNs allow for incorporation of a wider range of network characteristics but have substantially greater computation cost. These networks can be represented with graphs, allowing the use of graph theory tools to study the networks. I used Python to simulate flow and transport on a range of DFNs and analyzed these networks using methods from network analysis and spectral graph theory. My purpose was to find ways to gain insight about flow and transport on DFNs using these graph representations, bypassing the computationally intensive meshing typically required. My work is still in progress, but I have discovered several interesting trends and patterns that I believe could be useful towards my goal. If I am able to bring these results to fruition, they will aid subsurface geologists in extracting flow and transport information about fracture networks more efficiently.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2017

Understanding Data Structures by Extracting Memory Access Graphs

Understanding the data structures employed by a program is important for reverse engineering activities and can improve the results of automated software analysis techniques. In a compiled binary, access to data structure fields and array indices defined in the source program are replaced by raw pointer arithmetic. We present a representation for capturing the essential details of how a program accesses memory regions, which we call a Memory Access Graph (MAG), and a static analysis for automatically extracting this information from a program binary. The static analysis to extract the MAGs from the program is straightforward and does not require sophisticated integer or pointer analysis. The MAGs are readily understood by reverse engineers; they are generally able to perceive the data structure definition corresponding to a MAG. We briefly discuss automatic extraction of structure definitions outlining some of the difficulties in doing so.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2021

Understanding the Design Space of Sparse/Dense Multiphase Dataflows for Mapping Graph Neural Networks on Spatial Accelerators

Graph Neural Networks (GNNs) have garnered a lot of recent interest because of their success in learning representations from graph-structured data across several critical applications in cloud and HPC. Owing to their unique compute and memory characteristics that come from an interplay between dense and sparse phases of computations, the emergence of reconfigurable dataflow (aka spatial) accelerators offers promise for acceleration by mapping optimized dataflows (i.e., computation order and parallelism) for both phases. The goal of this work is to characterize and understand the design-space of dataflow choices for running GNNs on spatial accelerators in order for the compilers to optimize the dataflow based on the workload. Specifically, we propose a taxonomy to describe all possible choices for mapping the dense and sparse phases of GNNs spatially and temporally over a spatial accelerator, capturing both the intra-phase dataflow and the inter-phase (pipelined) dataflow. Using this taxonomy, we do deep-dives into the cost and benefits of several dataflows and perform case studies on implications of hardware parameters for dataflows and value of flexibility to support pipelined execution.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2021

Understanding Lustre Internals. Second Edition

The Lustre file system has become a preferred storage resource for systems on the Top500 list, and it is often the file system of choice for small- to medium-sized HPC systems that require parallel shared access to data. Several resources exist to help users deploy and configure Lustre, but the same cannot be said for resources that explain the inner workings of the Lustre source code. A previous ORNL technical report entitled "Understanding Lustre Filesystem Internals" (ORNL/TM-2009/117) provided an excellent summary of Lustre subsystem operations. However, that report is over a decade old and is based on Lustre version 1.6. Since that report was published, Lustre has evolved significantly. Several subsystems underwent significant code changes and many new features have been added to the file system, bringing the current Lustre version up to 2.15.This report aims to document and explain the internal workings of the latest version of the Lustre file system. It will provide more complete and up-to-date information than the previous technical report and should serve as a foundational document for anyone interested in Lustre software development. Key data structures will be described along with the APIs used for interaction among the various Lustre subsystems. Although the Lustre software is constantly being developed, the details in this document should remain relevant for the forseeable future.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2021

Molecular and Microstructural Bases for Understanding Microplastic Origin, Transport, and Fate

The formation of micro and nanoplastics from parent plastics is one of the most challenging ecological threats since plastic pollution reaches even the most desolate places on earth and is expected to double by 2030. The goal of this project is to understand physico-chemical properties on microplastics formation, transport, and fate by analyzing the microplastics found in environmentally collected samples at SRS, supported by lab-based experiments. An initial assessment found and identified microplastics and micronizing plastics in Fourmile Branch and the Savannah River. Fourmile Branch also carried trace-level radioactive contaminants associated with the Site’s legacy missions, which may incorporate into entrained microplastics.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Understanding Your Utility Bills: Water

Better Plants partners join the program by setting energy intensity goals over a 10-year period. Over the same period partners have the option to set water and waste goals. "Understanding Your Utility Bills: Water" is intended to help companies comprehend their bills and assist with analysis for annual reporting.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2020

DOE Early Career Award # DE-SC0012152: Understanding the Roles of Cloud Microphysics and Land Surface Coupling Feedbacks in Multi-Scale Predictions of Central US Summer Hydroclimate (Final Report)

This summarizes technical highlights from the DOE Early Career Project entitled “Understanding the Roles of Cloud Microphysics and Land Surface Coupling Feedbacks in Multi-Scale Predictions of Central US Summer Hydroclimate” led by PI Mike Pritchard at the University of California. The project’s original aims were to investigate trade-offs of cloud superparameterization such as the effects of microphysical assumptions on mesoscale convective systems (Section I) and the representation of land-atmosphere coupling under explicit convection (Section II). Under the same broader theme of water cycle dynamics, superparameterization, and land interaction, the project evolved to further investigate the climate dynamics of irrigation, vegetation and streamflow (Section III), the dynamics of the Madden- Julian Oscillation (Section IV), as well as the use of modern machine learning to replace traditional sub grid approaches for climate simulation (Section V). Twenty peer-reviewed journal publications were produced as a result of this project (Section VI).

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Understanding Weld Formation and Microstructure Evolution in Laser Welded Stainless Steels and Ti-6Al-4V

High energy density welding processes are used for many industrial applications, such as aerospace and defense, and certain joint configurations and welding situations render post-weld inspection techniques difficult. Due to the inability to confirm penetration, there is a continual industrial need to improve prediction capabilities to aid in parameter selection. It is also necessary to understand the microstructural evolution to modify phase fractions and mitigate weldability related concerns such as solidification cracking or reduced corrosion performance.

42 ENGINEERING↗
DOE OSTI2022

Understanding Novel Lewis Acid Doping Mechanisms in Organic Semiconductors

Recent studies supported by this DOE grant have provided a more detailed understanding of the doping mechanism of organic semiconductors by the Lewis acid, tris(pentafluorophenyl)borane (BCF). Our studies have examined the intermolecular semiconductor-dopant interactions as well as the thermodynamic feasibility of different doping mechanisms. Most notably, we found a different proposed doping scheme is much more thermodynamically favoured (exergonic) than our proposed two-step BCF doping mechanism. The state-of-the-art experimental and theoretical techniques of High-Field Multi-Dimensional Solid State NMR spectroscopy and Time-Dependent Density Functional theory (TD-DFT) and DFT were employed in this work. The data obtained helped identify the structural details and intermolecular interactions which impact the organic semiconductor doping efficiency for BCF and how these compare to the case of doping by the standard integer charge transfer dopant molecule F 4 TCNQ. We have, for the first time, assigned specific chemical shift values for the F 4 TCNQ molecules clustered outside of polymer chains as well as those intercalated between the polymer backbones. Further, we provide theoretical support for a novel doping mechanism which combines those proposed in previous literature involving the evolution of hydrogen gas along with a doping species more complex than the simple BCF·H 2 O. While our previously proposed doping mechanism was found to be highly thermodynamically unfavorable, the formation of large anion [BCF(OH)(OH 2 )BCF]- is the key change making the proposed mechanism exergonic while the elimination of gaseous H 2 helps drive the doping reaction.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Understanding Power Systems Protection in the Clean Energy Future

Wind and solar power and battery energy storage are often referred to as inverter-based resources (IBRs), which means they rely on power electronics (inverters) to generate grid-compatible electricity. This is unlike the fossil, nuclear, and hydroelectric plants that use spinning synchronous generators that have provided nearly all U.S. electricity until recently. Synchronous generators can inherently provide several services used to maintain a safe and stable grid and as they are replaced with IBRs it becomes important to understand how these services can be provided. One of these services is fault current, or the ability to inject large amounts of current during a short circuit. This current can easily be detected with low-cost equipment such as circuit breakers. IBRs do not inherently produce large amounts of fault current, and this may eventually require finding alternative sources of fault current or new system protection schemes. This document describes several alternative approaches to maintaining fault current protection and provide a safe, reliable power grid.

14 SOLAR ENERGY↗
DOE OSTI2021

Newly acquired core enhances geologic understanding of the northern Paradox Basin Cane Creek play, southeastern Utah

The Cane Creek interval is an emerging unconventional heterolithic play within the Pennsylvanian Paradox Formation of the northern Paradox Basin, southeastern Utah. Structural controls (basement uplifts, salt movement, faults, fractures) likely control production from the Cane Creek, where total oil production of ~10 MMBO is just a fraction of current estimates of the undiscovered resource (up to 1.2 BBOE). Oil production has been most successful from unstimulated horizontal wells in the Cane Creek Unit in the central play area, whereas areas to the north (Greentown and Gunnison Valley) have to date proven to be largely unproductive from vertical and horizontal wells drilled without the benefit of 3D seismic or the deployment of modern hydraulic fracturing techniques. However, the limited historical drilling has shown significant promise (e.g., significant shows). The lack of core data in the northern part of the play has impeded thorough assessment of reservoir quality, character, and lithological facies heterogeneity. The Cane Creek is informally divided into three distinct zones. The upper A and basal C zones are composed of fabric destructive and wavy bedded anhydrite, dolomitic mudstone, and organic-rich algal laminated mudstones (source rock). The middle B zone is generally wave rippled and burrowed, low-permeability sandstone-siltstone (reservoir) with subordinate displacive anhydrite. Recent potash cores collected from the Salt Valley anticline near Crescent Junction, Utah (but east of the main play area), show thicker reservoir sandstone/siltstone packages (~40 ft) in the B zone, and parts of the C zone, in the northern part of the Paradox Basin in comparison to the central (~35 ft) and southern (~30 ft) areas. Source rock analyses from northern core/cuttings also indicate that it is well positioned within the oil window (VRo ~0.8), with thin organic-rich mudstone beds containing up to 20 wt% TOC. Because the siliciclastic reservoir rocks have low permeabilities (0.009–0.202 mD) and variable porosities (6–17%) due to dolomite-anhydrite cement, naturally occurring and possibly stimulated fractures may be essential for hydrocarbon recovery. To better understand the northern part of the Cane Creek play, a new core was obtained from the research stratigraphic well State 16-2 (January 2021). Details from this new core will help characterize reservoir quality via core analyses, petrography, fracture orientations, geomechanics, and correlation of facies and depositional trends. Additionally, an evaluation of matrix porosity/permeability will be conducted to determine its contribution to productivity.

02 PETROLEUM↗
DOE OSTI2022

Understanding Photocarrier and Gas Dynamics to Rationally Design Heterostructured Nanocatalysts for Efficient Solar CO 2 Conversion

Recent research in CO 2 photocatalysis has largely focused on exploring new catalysts; however, details of the relationship between charge carrier dynamics and gas dynamics on the surface of nanomaterials often remain unclear. Knowledge of these processes will allow one to rationally design highly efficient catalysts for solar CO 2 conversion. This project aimed to develop state-of-the-art techniques and establish new capabilities in SRNL to enable the study of photocatalysts and other materials in detail. In FY21, we developed two new in situ techniques that are unique to SRNL, allowing the study of reaction intermediates and adsorbed gases during photocatalysis at various wavelengths of excitation. We also established a new in-house capability for catalyst synthesis and product evaluation which enables a deep understanding of how catalyst preparation methodologies impact product generation. In FY22, we gained in-house expertise and knowledge on the newly constructed a physical vapor deposition device, i.e. glancing angle deposition (GLAD) system, and constructed a flow photoreactor system for CO 2 photoconversion and other photocatalytic studies.

79 ASTRONOMY AND ASTROPHYSICS↗