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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

KCo 2 As 2 : A new portal for the physics of high-purity metals

High-quality single crystals of KCo 2 As 2 with the body-centered tetragonal ThCr 2 Si 2 structure were grown using KAs self flux. Structural, magnetic, thermal, and electrical transport properties were investigated. No clear evidence for any phase transitions was found in the temperature range 2–300 K. The in-plane electrical resistivity ρ versus temperature T is highly unusual, showing a T 4 behavior below 30 K and an anomalous positive curvature up to 300 K, which is different from the linear behavior expected from the Bloch-Grüneisen theory for electron scattering by acoustic phonons. This positive curvature has been previously observed in the in-plane resistivity of high-conductivity layered delafossites such as PdCoO 2 and PtCoO 2 . The in-plane ρ(T → 0) = 0.36μΩ cm of KCo 2 As 2 is exceptionally small for this class of compounds. The material also exhibits a magnetoresistance at low T which attains a value of about 40% at T = 2 K and magnetic field H = 80 kOe. The magnetic susceptibility χ of KCo 2 As 2 is isotropic and about an order of magnitude smaller than the values for the related compounds SrCo 2 As 2 and BaCo 2 As 2 . The χ increases above 100 K, which is found from our first-principles calculations to arise from a sharp peak in the electronic density of states just above the Fermi energy E F . Heat capacity C p (T) data at low T yield an electronic density of states N(E F ) that is about 36% larger than predicted by the first-principles theory. The C p (T) data near room temperature suggest the presence of excited optic vibration modes, which may also be the source of the positive curvature in ρ(T). Angle-resolved photoemission spectroscopy measurements are compared with the theoretical predictions of the band structure and Fermi surfaces. In conclusion, our results show that KCo 2 As 2 provides a new avenue for investigating the physics of high-purity metals.

36 MATERIALS SCIENCE↗
DOE OSTI2024

ATCCfinder - Download and Search the ATCC Genome Portal

Much strain-specific sequence data exists in research conducted before the deployment of large sequencing repositories, making it challenging to identify and validate the identity of strains used in these studies through bioinformatics and phenotyping. The American Type Culture Collection (ATCC) is an organization that sells a wide variety of microbes with strain-level taxonomy classification and associated sequenced reference genomes. Currently, ATCC does not provide a method for searching for sequence similarity between a query sequence and their database of reference genomes. Here I propose the software ATCCfinder, which utilizes ATCC application interface software (API) to generate query-able databases from ATCC Genome resources.

Koehler, Samuel↗
DOE OSTI2020

Overview of the U.S.-U.K. Portal Monitor for Authentication and Certification (PMAC) Project [Slides]

The PM designed and demonstrated under the PMAC project is a significant improvement from other existing PMs in terms of the joint host / inspector confidence provided and usability in a future hypothetical arms control regime. Based on these results, the PMAC system would be the best option currently available for a boundary control use case in a hypothetical arms control regime.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2025

Mass Spectrometry Sample Submission Portal

Each step in the scientific process generates contextual information about the data that is important to consider when performing data integration, developing models of biological process, or training AI models. We will develop a flexible, template-driven tool that will log biological samples, capture metadata about those samples, and track the type(s) of analysis being performed by researchers providing samples for analysis by mass spectrometry.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2026

Adaptable Standards for Discovery, Access, and Usability of Oak Ridge National Laboratory’s Data Portals and Catalogs

Oak Ridge National Laboratory (ORNL) is leveraging its established capabilities and subject matter expertise in data curation, governance, management, national security, and risk assessment and mitigation to support the US Department of Energy (DOE) Grid Modernization Initiative. Using standards modeled by the National Institute of Standards and Technology (NIST), the Data Curation Network (DCN), the Oak Ridge Leadership Computing Facility (OLCF), and other leading organizations in the fields of energy research, high-performance computing, and national and homeland security, ORNL seeks to provide a federated approach to research data discovery, use, and interoperability.

96 KNOWLEDGE MANAGEMENT AND PRESERVATION↗
DOE OSTI2026

Search for Dark Showers from Higgs Boson Decays Through the Photon Portal

One of the primary goals of the CMS detector is to find particles beyond the standard model. We present a search for dark showers produced from decays of the Higgs boson using collision data from the CMS experiment at the LHC. These dark showers then decay into jets made entirely of photons, which we can observe in the detector. Thus, our analysis focuses on reconstructing and analyzing these jets and maximizing signal selection efficiency for data from the Monte Carlo simulation. The photon signature of dark jets can then be confirmed via an invariant-mass distribution of these two photon jets. If found, these particles would provide evidence of physics theories beyond the Standard Model.

MacMullin, Alexandra [Skidmore Coll.]↗
DOE OSTI2024

Gravity as a Portal to Reheating, Leptogenesis and Dark Matter

Considering graviton as the only messenger that exists between the inflaton, the dark sector and the Standard Model (SM), we show, it is possible to simultaneously generate the observed relic density of dark matter (DM), the baryon asymmetry via leptogenesis, as well as successful reheating after inflation. Assuming the inflaton Φ oscillates in a monomial potential V(Φ) ∝ Φ k at the end of inflation, reheating via minimal gravitational interaction turns out to be excluded due to excessive production of gravitational wave (GW) energy density from inflation. We thus (a) extend the minimal model by considering a non-minimal gravitational contribution to radiation and (b)) propose an explanation for the PeV excess observed by IceCube, when the DM has an explicit Yukawa coupling to the SM leptong and Higgs. We also propose a novel scenario, where the gravitational production is a two-step process, through the production of a pair of scalars, that eventually decay into fermionic final states. Our framework gives rise to detectable primordial GW signal, that falls within the sensitivity of several proposed GW detectors.

Barman, Basabendu↗