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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Data sharing helps avoid “smoking gun” claims of topological milestones

Manipulating the topology of electronic bands can realize new states of matter, with possible implications for information technology. A central question is how to tell whether a topological regime has been achieved. Experiments are often guided by a prediction of a distinct and self-explanatory signal called “the smoking gun.” However, in micrometer- or nanometer-scale specimens, phenomenology can mimic the anticipated behavior without containing the exotic states. We show limited data that are consistent with the presence of four topological phenomena; by considering additional data, we identified the most likely origins of the observed patterns as trivial. Finally, we argue that the reliability of smoking gun–type claims can be greatly enhanced by releasing comprehensive datasets, discussing alternative scenarios, and disclosing the total volume of study.

Frolov, S. M. [Univ. of Pittsburgh, PA (United Sta↗
DOE OSTI2024

Manifold Learning: What, How, and Why

Manifold learning (ML), also known as nonlinear dimension reduction, is a set of methods to find the low-dimensional structure of data. Dimension reduction for large, high-dimensional data is not merely a way to reduce the data; the new representations and descriptors obtained by ML reveal the geometric shape of high-dimensional point clouds and allow one to visualize, denoise, and interpret them. This review presents the underlying principles of ML, its representative methods, and their statistical foundations, all from a practicing statistician's perspective. It describes the trade-offs and what theory tells us about the parameter and algorithmic choices we make in order to obtain reliable conclusions.

Mathematics↗
DOE OSTI2022

Repometer v.1.0

SAND2022-4256 O Online version control platforms offer insight into traffic and engagement with source code repositories, but only in limited ways and over short windows of time. Scientific software teams at Sandia National Laboratories and elsewhere want to collect and store engagement data to help tell their story and the impact their work has on the community. Repometer aims to supplement existing capabilities by collecting timely and insightful data from GitHub and GitLab repositories and passing it to a database for longer-term storage. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

Mundt, Miranda↗
DOE OSTI2025

Blue Keanu: A Scientific Visualization Tool For Network Data

This software allows the user to visualize complex PCAP-ng files captured from network capture software such as Wireshark. The visualization runs in a GUI window that can be zoomed or moved to areas of interest in a waterfall type display. The user then can see an area of interest that looks different than the typical traffic visually, such as a human interaction or non-repetitive area of data. The program will tell the user the packet number and byte offset of interest for fast analysis of discrete atomic or non-random events. This is particularly useful for visualization of unknown binary format data, such as in PLC or SCADA protocols that may have human or other non-repetitive activity for further analysis, reverse engineering, or fast forensic analysis.

Durller, MichaelGeorge↗
DOE OSTI2021

Humming Trains in Seismology: An Opportune Source for Probing the Shallow Crust

Abstract Seismologists are eagerly seeking new and preferably low-cost ways to map and track changes in the complex structure of the top few kilometers of the crust. By understanding it better, they can build on what is known regarding important, practical issues. These include telling us whether imminent earthquakes and volcanic eruptions are generating telltale underground signs of hazard, about mitigation of induced seismicity such as from deep injection of wastewater, how the Earth and its atmosphere couple, and where accessible natural resources are. Passive seismic imaging usually relies on blind correlations within extended recordings of Earth’s ceaseless “hum” or coda of well-mixed, small vibrations. In this article, we propose a complementary approach. It is seismic interferometry using opportune sources—specifically ones not stationary in time and moving in a well-understood configuration. Its interpretation relies on an accurate understanding of how these sources radiate seismic waves, precise timing, careful placement of pairs of listening stations, and seismic phase differentiation (surface and body waves). Massive freight trains were only recently recognized as such a persistent, powerful cultural (human activity-caused) seismic source. One train passage may generate a tremor with an energy output of a magnitude 1 earthquake and be detectable for up to 100 km from the track. We discuss the source mechanisms of train tremors and review the basic theory on sources. Finally, we present case studies of body- and surface-wave retrieval as an aid to mineral exploration in Canada and to monitoring of a southern California fault zone. We believe noise recovery from this new signal source, together with dense data acquisition technologies such as nodes or distributed acoustic sensing, will deeply transform our ability to monitor activity in the shallow crust at sharpened resolution in time and space.

Geochemistry & Geophysics↗
DOE OSTI2020

Cylinder Test

In 1941 G.I. Taylor proposed the cylinder test as an experiment to determine the properties of explosive products. The test consists of a hollow metal cylinder containing an unreacted cylindrical charge of explosives. The charge is detonated at one end of the cylinder and, as the detonation wave propagates, the product gas expands behind it. As the product gas is produced, the pressure acting on the metal increases and begins to push the walls outward. Consider the time at which the detonation wave has reached the halfway point between the two ends of the cylinder. In front of the wave nothing has changed and the metal tube has the same initial radius. Behind the wave, the radius of the tube has expanded. The farther behind the wave a section of tube is, the larger its radius has become. The longer the wall is exposed to the pressurized gas, the more it expands, so that the radius is largest where the detonation was initiated. The metal most commonly used for this experiment is soft copper. Its material properties are well known and soft copper is also easy to shape with precision machining. During the cylinder test the radial expansion of the cylinder is measured over time and this data is used to determine the amount of work applied to the cylinder wall by the product gas as a function of time. Since volume increases in this problem, the time dependence can be seen as a volume dependence. The volume dependent work yields a path in thermodynamic space. The cylinder test experiment can be modeled using simulation. The simulation gives you the answer, but it cannot tell you why. The goal of the proposed work is to use analytic analysis methods to give insight into the simulation solution.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Rapid Sample Insertion/Extraction Systems for Gamma Irradiation

The Rapid Sample Insertion/Extraction System for Gamma Irradiation, otherwise known as the "rabbit" system, was a four-week long project which included many different aspects; from coding an Arduino to building PVC piping to 3-D printing the "rabbit" capsules. The "rabbit" system is a system of PVC piping that allows a quick and efficient transfer of materials into/out of one of the irradiation chambers in the Gamma Irradiation Facility (GIF) with the use of a 3-D printed "rabbit." This "rabbit" encapsulates material to be irradiated and carries it from a position outside of the irradiation chamber to the basket inside of the chamber. The main purpose of this system is to save time and provide more exact data without any delays that normally occur when a person has to enter the chamber, retrieve data, and then analyze the data. This system should take measurements and retrieve the data instantaneously. The way in which the "rabbit" is sent through the PVC piping is with an advanced bi-directional, high-throughput pneumatic system, or a shop vacuum cleaner. When the vacuum is set to blow or suck then the "rabbit" will be pulled through the PVC piping to its intended destination and will hit sensors along the sides of the tubing when it reaches the end of the piping. These sensors tell the Arduino that the "rabbit" is finished moving throughout the tubing and stops a timer. Another timer is used to see how long the "rabbit" is being irradiated so when the "rabbit" reaches the sensors in the basket in the irradiation chamber another timer is started and it ends when the sensors no longer detect the "rabbit," which means that it has begun its journey back to the starting point.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2021

End-to-End Modeling of a Kilonova [Slides]

Outline of Talk: An overview of the process of forward modeling, from end to end - Emphasis on the disk, and neutrino transport.; A deeper look into a related system, a collapsar disk, and what it tells us about mergers.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2022

Current and Future Work on Wound Contamination by Alpha Emitters at Los Alamos [Slides]

Our team calculated ‘clinical decision levels’ at which treatment may be warranted (i.e., bioassay and wound measurements which correspond to specific dose thresholds). The actual risk to the patient corresponding to this dose threshold is uncertain – the CED may not tell the whole story. We recently reviewed LANL medical records to characterize adverse events associated with treatment. Future work should include medical records from other institutions and a review and analysis of data to quantify benefit of treatment with a focus on the question, "What factors predict whether treatment will be beneficial?"

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2022

Technology Integration to Gain Commercial Efficiency for the Urban Goods Delivery System, Meet Future Demand for City Passenger and Delivery Load/Unload Spaces, and Reduce Energy Consumption

This three-year project supported by the U.S. Department of Energy Vehicle Technologies Office has the potential to radically improve the urban freight system in ways that help both the public and private sectors. Working from 2018-2021, project researchers at the University of Washington’s Urban Freight Lab and collaborators at the Pacific Northwest National Laboratory have produced key data, tested technologies in complex urban settings, developed a prototype parking availability app, and helped close major knowledge gaps. All the fruits of this project can be harnessed to help cities better understand, support and actively manage truck load/unload operations and their urban freight transport infrastructure. Project learnings and tools can be used to help make goods delivery firms more efficient by reducing miles traveled and the time it takes to complete deliveries, benefitting businesses and residents who rely on the urban freight system for supplies of goods. And, ultimately, these project learnings and tools can be used to make cities more livable by minimizing wasted travel, which, in turn, contributes to reductions in fuel consumption and emissions. Cities today are challenged to effectively and efficiently manage their infrastructure to absorb the impacts of ever-increasing e-commerce-fueled delivery demand. All delivery trucks need to park somewhere to unload and load. Yet today’s delivery drivers have no visibility on available parking until they arrive at a site, which may be full. That means they can wind up cruising for parking, which wastes time and fuel and contributes to congestion. Once drivers do find parking, the faster they can unload at the spot, the faster they free up space for other drivers, helping others avoid circling for parking. This makes the parking space—and thus the greater load/unload network—more productive. To this end, the research team successfully met the project’s three goals, developing and piloting strategies and technologies to: 1. Reduce parking-seeking behavior in the study area by 20%; 2. Reduce parcel truck dwell time (the time a truck spends in a spot to load/unload) in the study area by 30%; 3. Increase curb space, alley space and private loading bay occupancy rates in the study area. The research team met these goals by creating and piloting on Seattle streets OpenPark, a first-of-its-kind real-time and forecasting curb parking app customized for commercial delivery drivers—giving drivers the “missing link” in their commonly used routing tools that tell them how best to get to delivery locations, but not what parking is available to use when they get there. Installing in-ground sensors on commercial vehicle load zones (CVLZs) and passenger load zones (PLZs) in the 10-block study area in Seattle’s downtown neighbourhood of Belltown let researchers glean real-time curb parking data. The research team also met project goals by piloting three parcel lockers in public and private spaces open to any delivery carrier, creating a consolidated delivery hub that lets drivers complete deliveries faster and spend less time parked. Researchers collected and analysed data to produce the first empirical, robust, statistically significant results as to the impact of the lockers, and app, on on-the-ground operations. In addition to collecting and analyzing sensor and other real-time and historical data, researchers rode along with delivery drivers to confirm real-world routing and parking behavior. Researchers also surveyed building managers on their private loading bay operations to understand how to boost usage.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2022

Parasitic Bacteria and Their Effect on Carbon Capture by Biofuel-Relevant Microalgae

The 2022 IPCC Sixth Assessment Report tells a worrying tale of global warming that temperatures will exceed beyond a 1.5 °C increase in the near future. Higher global temperatures result in more frequent and extreme weather events, irreversible ecosystem changes, and will contribute to detrimental impacts on human health. Anthropogenic greenhouse gas emissions— including those from burning fossil fuels for energy use—are the primary drivers of climate change. Organizations like the U.S Department of Energy’s (DOE) Office of Fossil Energy and Carbon Management (FECM) are working to decrease the environmental impacts of fossil fuels as society works towards net-zero emissions. To complete this goal, society must reduce its dependence on fossil fuels and move towards cleaner energy sources such as biofuels.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

The Connection of Adiabaticity to the Fourier Transform

This is probably the first thing I’d suggest anyone learns about adiabatic transitions because it tells you how a linear system reacts to an arbitrary forcing function. Not all systems are linear but they are usually locally linear near their stable fixed point. I think Scott Berg pointed out the relation to the Fourier transform to me and there’s probably literature about this under generic dynamical systems.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Easy_PERT: a Python tool for writing PERT cards and parsing PERT card results [Slides]

This presentation begins by providing an overview of the PERT card. The PERT card uses differential operator method to compute first- and second-order tally variations due to density, composition, and reaction cross-sections. It is possible to have multiple PERT cards in one MCNP input deck to study tally variations for several sets of nuclides, reactions, and energy ranges. Furthermore, the METHOD option tells MCNP to calculate either the perturbed tally (METHOD=-1, -2, -3) or the change in the unperturbed tally (METHOD=1, 2, 3). In summation, a powerful use-case for the MCNP code PERT card is that it facilitates calculating tally sensitivities to nuclear data. Writing PERT card entries and parsing output MCTAL files is tedious and error prone. however, Easy_PERT makes use of existing tools (Faust and MCNPTools) to handle writing PERT card entries and parsing the output MCTAL files. The PERT card is early in the development process and planned upcoming capabilities include calculating sensitivities and combining MCTAL files from separate runs into one JSON file.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2021

A Nuclear Security Enterprise Study of High-Reliability Systems, Collaboration, and Data

It may seem simple and trivial, but defining the difference between data and information is contested and has implications that may affect the security of United States interests and even cost lives. For security, data are raw facts or figures without context, while information is the compilation or articulation of data that forms context. Security depends on clarity in the differences between data and information and controlling them. Control is necessary to ensure that data and information are not inadvertently released to foreign governments, the public, or those without Need-to-Know. A primary concern in the practice of security is the control of data to avoid the inadvertent conversion to sensitive information. The complexity of this concern is further augmented when institutions are part of tightly coupled networks that informally share data and information. Additionally, those that share data as a function of legislative action—and/or formally integrate data and information system infrastructures—may be a higher security risk. This paper will present a case study that utilizes elements of literature from Knowledge Management and networks to tell a story of an issue in security—specifically, controlling the conversion of data to information.

96 KNOWLEDGE MANAGEMENT AND PRESERVATION↗
DOE OSTI2023

Ombuds Office 2023 Biennial Report

The Los Alamos National Laboratory (LANL) Ombuds Charter requires the Ombuds Office to issue a report every two years to the Laboratory Director. The prior Ombuds Biennial Report was published in July of 2021, celebrating 25 years of Ombuds history at the Lab. This 2023 report details office transitions and new initiatives over the past two years, along with our ongoing conflict resolution work of one-on-one discussions, classes, presentations, workshops, and facilitations. The Ombuds Office supports the mission of LANL in myriad ways. We champion the LANL culture statement of “ How we do work is as important as What we do,” and we reinforce LANL’s values of integrity, service, excellence, and teamwork. Accordingly, the mission of the Ombuds Office is to support employees in their work, enhance communication, mitigate conflict, and encourage a positive working environment. The Ombuds Office adheres to the International Ombuds Association’s (IOA) Standards of Practice and Code of Ethics (see Appendix). As such, the Ombuds Office is informal, confidential, impartial, and independent. We do not advocate for managers or employees. We don’t tell people what to do; we don’t give advice. All of our services are voluntary. LANL employees seek out the Ombuds Office as a neutral place where they can collect their thoughts, whether in person, on the phone, or online. We help individuals explore and navigate tough issues. Employees expand their understanding of their options, assess what is within their control, and decide what is in their best interest. The Ombuds Office promotes smart, professional conflict management. This report highlights the work of the Ombuds Office and provides a closer look at both quantitative and qualitative data, including anecdotal information and endorsements. It concludes with a discussion of further opportunities to expand the reach of the Ombuds Office to more LANL employees.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2024

In-situ TEM EELS analysis of memristive thin films for neuromorphic computing

Neuromorphic computing stands as a promising frontier for advancing AI algorithms and applications like ChatGBT, offering significant energy efficiency gains. This paper delves into the hardware design intricacies of memristive thin films and their elementary switching mechanisms, including anion migration, electron migration, and phase transitions. Through comprehensive analysis of electron energy loss spectroscopy (EELS) data via in-situ transmission electron microscopy (TEM), we will deduce the primary memristive switching mechanisms vital for optimizing thin film fabrication parameters and achieving desired film thickness, conductivity, and memory retention. A single crystal ptype Si substrate was used with TiN as the bottom metal electrode, TiO x as the insulating dielectric layer, and Pt as the top metal electrode. In-situ TEM was able to tell us the thin film didn’t behave like a filamentary or phase transition material. EELS data deduced that electron trapping/detrapping was one of the primary switching mechanisms. By shedding light on these elementary mechanisms, our study aims to catalyze the development of more 2 efficient and effective neuromorphic computing systems to be deployed into mainstream technologies.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2025

CSAC observations from 2025 CHEDAR review [Slides]

Overall, the CSAC is impressed by the strong start of CHEDAR, a multi-institutional center with broader scope than its predecessor. The CSAC was impressed and energized by discussions with center students and staff; the enthusiasm for science is universal and the sense of the contribution in context to the NNSA mission is mostly understood. The Center is well positioned to build on a strong start and (1) enhance integration of code-development targeted to, and numerical design in on-going experimental campaigns, (2) focus and better tell the story of the astrophysical connection for on-going experimental campaigns, and (3) expand and deepen ties between Center students (and faculty) and the NNSA National Laboratories. Overall, the CSAC was encouraged and energized by the materials presented. Now, the Center has to recognize the need to continue growing strategically. There is abundant access to experimental facilities – is that a challenge to focused effort? The PIs will need to balance the pace of experimental campaigns and analysis and simulation so that informed progress and focused investigation can develop in each campaign. There was a clear need to connect simulations to the goals of experimental campaigns – what is the best way to cultivate that connection? Are there adequate resources in the near term to develop code capability? What is the balance between close personal mentorship and collaboration across the separate institutions that compose the Center? The CSAC feels confident that the team leading CHEDAR will find creative solution to these challenges.

47 OTHER INSTRUMENTATION↗