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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 829 records · Page 46
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Using Hough harmonics to validate and assess nonlinear shallow-water models

The implementation of a technique for locating programming errors in shallow-water codes, establishing the correctness of the code, and assessing the performance of the numerical model under various flow conditions is described. The right-hand side of the differential equations is modified in such a way that the exact solution of the nonlinear initial-value problem is known, so that the truncation errors of the numerical scheme can be studied in detail. The exact solution is prescribed to be any linear combination of Hough harmonics which propagate in time according to their natural frequencies.

Dee, Dick P.↗
NASA NTRS1990

Capillary Pumped Loop Modeler

Capillary Pumped Loop (CPL) Modeler computer program is amalgamation of software that mathematically models performance of CPL system and its environment. Two-phase heat-transport device capable of transferring heat loads efficiently over large distance with little temperature differential. Utilizes surface-tension forces established in fine-pore capillary wick to circulate working fluid, requiring no external pumpling power. Predicts steady-state or quasi-steady behavior of CPL embedded in spacecraft or other thermal environment. Also predicts location of liquid/vapor interface in each condenser. Written in VAX/VMS FORTAN 77.

Ku, Jentung↗
NASA NTRS1999

Major Optical Outburst of Two Blazars: 3C66A and OJ287

Differential CCD photometric observations of 3C66A and OJ287 were carried out on 16 and 35 nights between December 1995 and March 1996, at the Vainu Bappu Observatory, India, as part of the blazar monitoring program. During this period we detected major optical outbursts (brightness of 3C66A and OJ287 increased by 0.8 and 1 mag, respectively) of these two blazars on timescales of two months. Integrating the outburst profiles we find that both the blazars released around 10(exp 53) erg. Such large amount of energy may come from the release of binding energy of a compact star when tidally disrupted by a super-massive black hole at the center of these blazars. Also we extend this model to explain the observed multifrequency (radio through gamma-ray) outburst of these two blazars and show that this model will be able to explain the outburst phenomena of other blazars. These new results will be presented with a detailed discussion of the suggested model.

Ghosh, K. K.↗
NASA NTRS2016

Design Overview of the DM Radio Pathfinder Experiment

We introduce the DM Radio, a dual search for axion and hidden photon dark matter using a tunable superconducting lumped-element resonator. We discuss the prototype DM Radio Pathfinder experiment, which will probe hidden photons in the 500 peV (100 kHz)-50 neV (10 MHz) mass range. We detail the design of the various components: the LC resonant detector, the resonant frequency tuning procedure, the differential SQUID readout circuit, the shielding, and the cryogenic mounting structure. We present the current status of the pathfinder experiment and illustrate it's potential science reach in the context of the larger experimental program.

axion↗
DOE OSTI2021

Cooling charge determination for a local thermal management system

A system and method for estimating the state of charge, i.e., the amount of cooling remaining, in a latent heat thermal storage module of a local environmental control system. The local environmental control system stores cooling energy at night by freezing a latent heat phase change material (PCM), and then releasing the stored cooling energy by removing heat from room air flowing through the PCM during the day. Differential temperature sensors are used measure the air temperature drop across the latent thermals storage unit and the fan voltage, which is directly related to fan air flow rate, is sampled. A controller is programmed to determine the charging state from these measurements.

Khalifa, H. Ezzat↗
DOE OSTI2023

Advancing the Theory of Nuclear Data Evaluations [Abstract]

We present recent advances in the R-matrix formalism as well as the Bayesian evaluation framework for improved nuclear data evaluations. The advances in the R matrix formalism include: 1) direct processes, 2) doorway, as well as multistep, processes, and 3) various forms of the Reich-Moore approximation for eliminated capture channels. Furthermore, to address unreasonably small posterior uncertainties often encountered in nuclear data evaluations of large data sets using the conventional form of the Bayes’ theorem, we introduce imperfections (of the data or the model) as a formal evaluation tool for taming the evaluated uncertainties in harmony with Bayes’ theorem. These theoretical advances were motivated by the nuclear data evaluations of differential resolved resonance cross section data using the code SAMMY, as well as the integral benchmark experiments using the SCALE code system, being performed at Oak Ridge National Laboratory for the Nuclear Criticality Safety Program. Some pedagogical applications of the new formalism, as well as a snapshot of the SAMMY modernization efforts, will be presented.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
NASA NTRS1990

Preosteoblast production 55 hours after a 12.5-day spaceflight on Cosmos 1887

The influence of 12.5 days of spaceflight and a 55 h stressful recovery period (at 1 g) on fibroblastlike osteoblast precursor cells was assessed in the periodontal ligament (PDL) of rats that were 91 days old at launch. Nuclear morphometry was used as a marker for precursor cell differentiation in 3 microns sections cut in the midsagittal plane from the maxillary first molar. According to nuclear volume, cells were classified as preosteoblasts (C + D cells, greater than or equal to 120 microns 3) and less differentiated progenitor cells (A + A' cells, 40-79 microns 3). Compared with synchronous controls (simulated flight conditions), the 55 h postflight recovery period at 1 g resulted in a 40% decrease in the A + A' cell population, a 42% increase in the C + D cells, and a 39% increase in the number of PDL fibroblastlike cells near the bone surface. These results are consistent with a postflight osteogenic response in PDL. This recovery response occurred despite physiological stress in the flight animals that resulted in a highly significant (P less than or equal to 0.001) increase in adrenal weight. The data suggest that after spaceflight there is a strong and rapid recovery mechanism for osteoblast differentiation that is not suppressed by physiological stress.

Cosmos 1887 Project↗
DOE OSTI2016

Features in simulation of crystal growth using the hyperbolic PFC equation and the dependence of the numerical solution on the parameters of the computational grid

We investigate the three-dimensional mathematical model of crystal growth called PFC (Phase Field Crystal) in a hyperbolic modification. This model is also called the modified model PFC (originally PFC model is formulated in parabolic form) and allows to describe both slow and rapid crystallization processes on atomic length scales and on diffusive time scales. Modified PFC model is described by the differential equation in partial derivatives of the sixth order in space and second order in time. The solution of this equation is possible only by numerical methods. Previously, authors created the software package for the solution of the Phase Field Crystal problem, based on the method of isogeometric analysis (IGA) and PetIGA program library. During further investigation it was found that the quality of the solution can strongly depends on the discretization parameters of a numerical method. In this report, we show the features that should be taken into account during constructing the computational grid for the numerical simulation.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2021

Updates to the n+ 63,65 Cu Angular Distributions [Slides]

The performance of the benchmark suite is very sensitive to changes in the angular distribution data. The quasi-differential measurements performed by Blain et al at RPI provide a valuable constraint. Furthermore, ENDF/B-VIII.0 disagrees with their measurements consistently at 300 keV (the transition between RRR and high energy). The next step is to conservatively adjust the Legendre coefficients near 300 keV, validating performance against both critical benchmarks and the RPI quasi-differential measurements.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
NASA NTRS1988

Sculpturing new muscle phenotypes

Changes in the pattern of muscle activity are followed by new patterns of protein synthesis, both in the contractile elements and in the enzymes of energy metabolism. Although the signal transducers have not been identified, techniques of molecular biology have clearly shown that the adaptive responses are the regulated consequence of differential gene expression.

Non-NASA Center↗
NASA NTRS1996

Cell proliferation and hair cell addition in the ear of the goldfish, Carassius auratus

Cell proliferation and hair cell addition have not been studied in the ears of otophysan fish, a group of species who have specialized hearing capabilities. In this study we used the mitotic S-phase marker bromodeoxyuridine (BrdU) to identify proliferating cells in the ear of one otophysan species, Carassius auratus (the goldfish). Animals were sacrificed at 3 h or 5 days postinjection with BrdU and processed for immunocytochemistry. The results of the study show that cell proliferation occurs in all of the otic endorgans and results in the addition of new hair cells. BrdU-labeled cells were distributed throughout all epithelia, including the primary auditory endorgan (saccule), where hair cell phenotypes vary considerably along the rostrocaudal axis. This study lays the groundwork for our transmission electron microscopy study of proliferative cells in the goldfish ear (Presson et al., Hearing Research 100 (1996) 10-20) as well as future studies of hair cell development in this species. The ability to predict, based on epithelial location, the future phenotype of developing hair cells in the saccule of the goldfish make that endorgan a particularly powerful model system for the investigation of early hair cell differentiation.

NASA Discipline Number 40-10↗
DOE OSTI2021

Double-differential Measurements of Mesonless Charged-current Muon Neutrino Interactions on Argon with Final-State Protons using the MicroBooNE Detector

This note reports the first double-differential measurements of charged-current $ν_µ$ scattering on argon leading to final states containing zero mesons and one or more protons. This event topology (hereafter abbreviated as CC0$πNp$) is the most common at the neutrino energies typically produced by the Fermilab Booster Neutrino Beam. A detailed understanding of neutrino-argon scattering in the CC0$πNp$ channel is therefore crucial for the success of the precision neutrino oscillation analyses planned for the Short-Baseline Neutrino (SBN) program. This remains true for the upcoming Deep Underground Neutrino Experiment (DUNE), but the higher mean neutrino energy used there will ensure that more inelastic reaction modes, such as single pion production, will also play a major role. The analysis described in this note builds on a previous MicroBooNE study of the CC0$πNp$ channel which obtained the first single-differential cross-section measurements on an argon target. Since that foundational work, significant improvements have been made to MicroBooNE’s simulation software, event reconstruction algorithms, and procedure for calculating systematic uncertainties. When combined with a larger dataset (corresponding to a beam exposure of 6.79 × 10 20 protons-on-target versus 1.60 × 10 20 in Ref. [3]), these enhancements allow the important CC0$πNp$ channel to be studied in more detail. This note begins with a description of the data and simulation samples used as input to the analysis. Section 3 then defines the CC0$πNp$ signal event topology, and Section 4 describes a set of selection criteria designed to identify these events in MicroBooNE data. Binning schemes are then defined in Section 5 for two double-differential measurements of event rates. The first of these considers the momentum and scattering cosine of the outgoing muon, while the second reports the same observables for the leading proton, i.e., the final-state proton with the largest momentum. After a discussion of systematic uncertainties in Section 6, the note concludes by comparing the predictions of MicroBooNE Monte Carlo (MC) simulations to the measured double-differential distributions. These results will form the basis for a future extraction of flux-averaged double-differential CC0$πNp$ cross sections that will be immediately comparable to the theoretical predictions of multiple neutrino event generators. The selection described herein may also be used to study various other observables in CC0$πNp$ events, including those which are sensitive to correlations between leptonic and hadronic kinematics in the final state.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2018

Privacy-Preserving Aggregation of Controllable Loads to Compensate Fluctuations in Solar Power

Cybersecurity and privacy are of the utmost importance for safe, reliable operation of the electric grid. It is well known that the increased connectivity/interoperability between all stakeholders (e.g., utilities, suppliers, and consumers) will enable personal information collection. Significant advanced metering infrastructure (AMI) deployment and demand response (DR) programs across the country, while enable enhanced automation, also generate energy data on individual consumers that can potentially be used for exploiting privacy. Inspired by existing works which consider DR, battery-based perturbation, and differential privacy noise adding, we novelly consider the aggregator (cluster) level privacy issue in the DR framework of solar photovoltaic (PV) generation following. Different from most of the existing works which mainly rely on the charging/discharging scheduling of rechargeable batteries, we utilize controllable building loads to serve as virtual storage devices to absorb a large portion of the PV genertaion while delicately keeping desired noisy terms to satisfy the differential privacy for the raw load profiles at the aggregator level. This not only ensures differential privacy, but also improves the DR efficiency in load following since part of the noisy signal in solar PV generation has been filtered out. In particular, a mixed integer quadratic optimization problem is formulated to optimally dispatch a population of on/off controllable loads to achieve this privacy-preserving DR service.

Dong, Jin↗
DOE OSTI2024

NEAMS-Multiphysics MOOSE End Year Framework Activities FY20

The Multiphysics Object Oriented Simulation Environment (MOOSE) is a general finite element package meant for high performance solution of multiphysics problems in science and engineering. In this report, we present additions and enhancements to MOOSE funded by the Nuclear Engineering Advanced Modeling and Simulation (NEAMS) program. NEAMS-funded MOOSE framework library improvements include: expansion of support for multi-level multi-application restart; enhancement of coupling between native MOOSE applications and external libraries; addition of a sparse automatic differentiation (AD) container enabling non-local degree of freedom coupling; block-specific quadrature rules; further development of an eigenvalue executioner; faster setup of periodic boundary conditions; and creation of a mesh meta-data system streamlining simulation startup. Besides developing the framework library, NEAMS funds were used to overhaul a swath of important MOOSE infrastructure in order to substantially improve user experience. These critical infrastructure changes included adapting MOOSE to python 3, improving the test harness to catch race conditions, and most importantly transitioning MOOSE to use Conda, a globally known packaging system, that greatly eases software adoption.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2026

Inclusive Charged-Current Electron Neutrino Interactions in SBND

The Short-Baseline Near Detector (SBND), a 112 ton liquid argon time projection chamber (LArTPC), is the near detector of the Short- Baseline Neutrino Program at Fermilab. Due to its proximity to the Booster Neutrino Beam target, SBND has already seen a record-breaking number of electron neutrino interactions on argon. We present preliminary results from SBND’s differential inclusive electron neutrino charged-current analysis from our first year of beam data, selecting over 2,000 interactions. This analysis will present the largest sample of electron neutrinos on argon to date, as well as the first differential cross section measurement of electron neutrinos. This poster will give an overview of the selection, cross-section extraction, and demonstrate SBND’s detector and electromagnetic shower reconstruction performance through data/MC comparisons.

Tung, Lynn [Chicago U.]↗
NASA NTRS1972

Numerical analysis of the transient response of an axisymmetric ablative char layer considering internal flow effects

The differential equations governing the transient response of the char layer of an ablating axisymmetric body, internal pyrolysis gas flow effects being considered, have been derived. These equations have been expanded into finite difference form and programed for numerical solution on a digital computer. Numerical results compare favorably with simplified exact solutions. The complete numerical analysis was used to obtain solutions for two representative body shapes subjected to a typical entry heating environment. Pronounced effects of the lateral flow of pyrolysis gases on the mass flow field within the char layer and the associated surface and pyrolysis interface recession rates are shown.

Pittman, C. M.↗
NASA NTRS1978

Use of piloted simulation for studies of fighter departure/spin susceptibility

The NASA-Langley Research Center has incorporated into its stall/spin research program on military airplanes the use of piloted, fixed-base simulation to complement the existing matrix of unique research testing techniques. The piloted simulations of fighter stall/departure flight dynamics are conducted on the Langley Differential Maneuvering Simulator (DMS). The paper reviews the objectives of the simulation research, presents the rationale underlying the simulation methods and procedures used in the evaluation of airplane characteristics, and discuss in detail the evaluation steps used to assess fighter stall/departure characteristics. Simulation results are presented to illustrate the flight-dynamics phenomena dealt with. The use of the piloted simulation methods and procedures described has been found very effective in identifying stability and control problem areas and in developing automatic control concepts to alleviate many of these problems. A good level of correlation between simulated flight dynamics and flight-test results has been obtained over the many fighter configurations studied in the simulator.

Gilbert, W. P.↗