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All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

A New Measurement of the Neutron Electric Form Factor with the Super Bigbite Spectrometer Apparatus

Protons and neutrons, collectively known as nucleons, make up the nuclei at the core of atoms which form our world. The nucleon has been under intensive study for over 100 years, and yet we still do not fully understand the internal dynamics which govern properties like its spin or its mass-which contributes to almost all of the visible mass in the universe. These dynamics are governed by quantum chromodynamics(QCD), the predictions of which are experimentally tested at high energy accelerator facilities such as Jefferson Lab. TheGEN-II experiment (E12-09-016) is one such experiment. GEN-II is part of the Super Bigbite Spectrometer (SBS) experimental form factor pro gramme taking place in Hall A at Jefferson Lab, which aims to make precision measurements of the nucleon electromagnetic form factors(EMFFs)at record high values of squared four momentum transfer ¿2. EMFFs describe the electric and magnetic moment distributions within the nucleon. They can be measured through elastic electron scattering off the nucleon, and describe the recoil response of the target nucleon at a given energy scale. GEN-II is a double polarized semi-exclusive beam target asymmetry (BTA) experiment, seeking to measure the electric form factor of the neutron,¿¿ ¿,at three new values of squared four-momentum transfer¿2 =2.92,6.74and9.82GeV². The latter two points being at record high ¿2. The form factor is determined through measuring the BTA of quasielliptical scattering of a neutron from a polarized nuclear target. The experiment utilized the CEBAF accelerator to produce longitudinally polarized electrons up to ~85% polarization, which were scattered off neutrons within a novel polarized helium-3 (³He) target. This new polarized ³He target was employed by building on the technology of its precursors which existed in similar preceding experiments. This target was designed to operate at the high luminosities typical of Hall A, and reached a record breaking combination of polarization and beam intensity known as figure of merit, three times larger than those predecessors. The SBS collaboration designed and constructed two brand new high acceptance spectrometers for these experiments, an electron arm named Bigbite (BB) and a hadron arm named Super Bigbite. Both spectrometers featured a large acceptance EM dipole magnet, and complementary detector systems. The electron arm contained gaseous electronmultipliers(GEMs) which were used for high precision tracking of the scattered electrons, a heavy gas cherenkov (GRINCH) which was used for PID between electrons and pions, a plastic i ii scintillator timing hodoscope to provide high resolution timing of the start of events, and a pair of EM calorimeters (BBCal) which provided energy measurements of detected particles, and provided the experimental trigger. The hadron arm also contained a system of GEMs which will be utilized for future SBS experiments, and a hadron calorimeter designed to provide position, timing and energy measurements of the recoiling nucleon. The calibration of all detector subsystems, beam and target data is discussed, with a focus on novel timing calibrations to the hodoscope and hadron calorimeter. An analysis of selecting quasielliptical events and suppressing background contributions from a number of sources which contaminate the final event sample is given. The largest irreducible backgrounds are found to be from misidentified protons, timing accidentals and inelastic events. The physical asymmetry is measured and used to extract a value for the form factor ratio ¿¿ ¿/¿¿ ¿. High precision ¿2 data for ¿¿ ¿ is used to then extract ¿¿ ¿. This work finds at ¿2 = 2.92 GeV2 that ¿¿ ¿ = 0.0129+0.0019 -0.0020. This result is in statistical agreement with existing fits to world data, and predictions from the constituent quark model and Dyson–Schwinger equations, in this region of ¿2.

Penman, Gary [Univ. of Glasgow, Scotland (United K↗
NASA NTRS2016

Lunar COTS: Using the Moon's Resources to Enable An Economical and Sustainable Pathway to Mars and Beyond

To support NASAs goal of sending humans to Mars, a new plan was constructed to develop and demonstrate cislunar capabilities and services in partnership with commercial industry using the well-proven Commercial Orbital Transportation Services (COTS) Program acquisition model. The NASA COTS Program was a very successful program that developed and demonstrated cost-effective commercial cargo transportation services to the International Space Station (ISS). As a result of NASAs COTS program, two new launch vehicles and spacecraft were developed and have been successfully performing cargo transportation missions to the ISS since 2012. The COTS acquisition strategy utilized a new model than normally accepted in traditional procurement practices. This new model used Space Act Agreements where NASA entered into partnerships with industry to jointly share cost, development and operational risks to demonstrate new capabilities for mutual benefit. This model proved to be very beneficial to both NASA and its industry partners as NASA saved significantly in development and operational costs, as much as tenfold, while industry partners successfully expanded their market share of the global launch transportation business for significant economic benefit. Using the COTS acquisition model as a basis, a new plan, notionally referred to as Lunar Commercial Orbital Transfer Services (or Lunar COTS), has been developed to determine the potential benefits and challenges of a new Lunar COTS plan[1]. The proposed plan includes low-cost, commercial-enabled missions to prospect for resources, determine the economic viability of extracting those resources and assess the value proposition of using these resources in future exploration architectures such as Mars. These missions would be accomplished in partnership with industry to meet these exploration goals but will also have the capability to carry payloads to meet science goals as well.

Zuniga, Allison↗
NASA NTRS2016

Failure Simulation Testing of the Z-1 Spacesuit Titanium Bearing Assemblies

The Z-2 is a candidate for NASA's next generation spacesuit, designed for a range of possible missions with enhanced mobility for spacewalks both on planetary surfaces and in microgravity. Increased mobility was accomplished through innovations in shoulder and hip joints, using a number of new bearings to allow spacesuit wearers to dip, walk, and bend with ease; all important tasks for a planetary explorer collecting samples or traveling over rough terrain. The Advanced Spacesuit Development Team of NASA Johnson Space Center requested that the NASA White Sands Test Facility (WSTF) perform a series failure simulation tests on three titanium bearing assemblies, an elemental part of the joint construction used in new spacesuit designs. This testing simulated two undetected failures within the bearings and as a result the objective of this test program was to evaluate whether a failed or failing bearing could result in ignition of the titanium race material due to friction. The first failure was an inner seal leak sufficient to pressurize the race with +99 percent oxygen. The second failure was an improperly installed or mismatched ball port that created a protrusion in the ball bearing race, partially obstructing the nominal rolling path of each ball bearing. When the spacesuit bearings are assembled, bearing balls are loaded into the assembly via a ball port. The ball port is specific and unique to each bearing assembly (matched pair). The simulated mismatched ball port is a significant source of friction, which would be caused by an assembly error. To evaluate this risk, the bearings were cycled in a simulated worst-case scenario environment, with operational loads, and potential flaw conditions. During test the amount of actuation torque required and heat generated through continuous operation were measured and the bearings were observed for sparks or burning events. This paper provides detailed descriptions of the test hardware, methodology, and results.

de Baca, Richard C.↗
DOE OSTI2021

Software Verification and Validation Guidelines for Non-Linear Soil-Structure Interaction Analysis

Seismic analysis of structures, systems, and components (SSCs), including the consideration of soil-structure interaction (SSI) effects, is an important and required step in the design and licensing of nuclear power plant SSCs important to safety. Historically, the SSI analysis of nuclear structures has been performed using equivalent linear methods. However, there has been considerable industry investment in alternative seismic design and analysis approaches to reduce the construction cost of new reactors. Toward that goal and in alignment with the Licensing Modernization Project (LMP) framework, the Nuclear Regulatory Commission (US NRC) has proposed a risk-informed, performance-based approach to seismic design that allows inelastic response in those nuclear plant structures not required for confinement. As a complementary effort, reactor designers are exploring nonlinear seismic analysis methods to optimize structural designs and reduce construction costs.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
NASA NTRS1995

Laboratory studies of low temperature rate coefficients: The atmospheric chemistry of the outer planets

The objectives of the research are to measure low temperature laboratory rate coefficients for key reactions relevant to the atmospheres of Titan and Saturn. These reactions are, for example, C2H + H2, CH4, C2H2, and other hydrocarbons which need to be measured at low temperatures, down to approximately 150 K. The results of this work are provided to NASA specialists who study modeling of the hydrocarbon chemistry of the outer planets. The apparatus for this work consists of a pulsed laser photolysis system and a tunable F-center probe laser to monitor the disappearance of C2H. A low temperature cell with a cryogenic circulating fluid in the outer jacket provides the gas handling system for this work. These elements have been described in detail in previous reports. Several new results are completed and the publications are just being prepared. The reaction of C2H with C2H2 has been measured with an improved apparatus down to 154 K. An Arrhenius plot indicates a clear increase in the rate coefficient at the lowest temperatures, most likely because of the long-lived (C4H3) intermediate. The capability to achieve the lowest temperatures in this work was made possible by construction of a new cell and addition of a multipass arrangement for the probe laser, as well as improvements to the laser system.

Leone, Stephen R.↗
NASA NTRS2019

Weighted Least-Squares Cell-Average Gradient Construction Methods for the VULCAN-CFD Second-Order Accurate Unstructured-Grid Cell-Centered Finite-Volume Solver

The ability to solve the equations governing the hypersonic turbulent flow of a real gas on unstructured grids using a spatially-elliptic, 2nd-order accurate, cell-centered, finite-volume method has been recently implemented in the VULCAN-CFD code. The construction of cell-average gradients using a weighted linear least-squares method and the use of these gradients in the construction of the inviscid fluxes is the focus of this paper. A comparison of least-squares stencil construction methodologies is presented and approaches to augment the number of cells participating in the stencil while preserving accuracy are explored. Due to our interest in hypersonic flow, a robust multidimensional cell-average gradient limiter procedure that is consistent with the stencil used to construct the cell-average gradients is described and investigated. Canonical problems are computed to illustrate the challenges and investigate the accuracy, robustness and convergence behavior of the cell-average gradient methods on unstructured cell-centered finite-volume grids. Finally, thermally perfect, chemically frozen, Mach 8 turbulent flow of air around a blunt wedge is computed to demonstrate the robustness and convergence behavior of the new method for constructing stencils of use in a weighted linear least-squares gradient method for a hypersonic flow.

White, Jeffery A.↗
NASA NTRS1991

The advanced microwave precipitation radiometer: A new aircraft radiometer for passive precipitation remote sensing

Past studies of passive microwave measurements of precipitating systems have yielded broad empirical relationships between hydrometeors and microwave transmission. In general, these relationships fall into two categories of passive microwave precipitation retrievals rely upon the observed effect of liquid precipitation to increase the brightness temperature of a radiometrically cold background such as an ocean surface. A scattering-based method is based upon the effect that frozen hydrometeors tend to decrease the brightness temperature of a radiometrically warm background such as land. One step toward developing quantitative brightness temperature-rain rate relationships is the recent construction of a new aircraft instrument sponsored by National Aeronautics and Space Administration/Marshall Space Flight Center (NASA/MSFC). This instrument is the Advanced Microwave Precipitation Radiometer (AMPR) designed and built by Georgia Tech Research Institute to fly aboard high altitude research aircraft such as the NASA ER-2. The AMPR and its accompanying data acquisition system are mounted in the Q-bay compartment of the NASA ER-2.

Hood, Robbie E.↗
DOE OSTI2024

Evaluating disease surveillance strategies for early outbreak detection in contact networks with varying community structure

Disease surveillance systems allow public health agencies to respond to emerging diseases before they become widespread. Developing such systems requires identifying optimal ways to monitor in the context of an epidemic outbreak; this problem is known as sensor selection. Contact networks represent the dynamics of interaction in a population and are used to model how a disease spreads in a population and to explore strategies of sensor selection. We evaluated five sensor selection strategies on their ability to provide an early warning of a COVID-like outbreak in synthetic contact networks encapsulated in four network scenarios. Three of these scenarios assessed different aspects of community structure. The fourth scenario employed a contact network representing the population and interactions of 6.8 million people in New York City, constructed from an agent-based simulation using census and transportation data. This scenario exemplifies how sensor selection strategies may perform in a real-world, urban context. Our findings suggest that the choice of the optimal strategy depends heavily on the community structure of the network. Strategies that select highly connected nodes or maximize network coverage are the optimal surveillance strategy for outbreak detection in many network community structures. However, a naive implementation of these strategies may fail to provide an early warning at all—including in the New York City scenario. Moreover, these methods are impractical for real-world use as they require knowledge of the underlying contact network. Instead, a selection strategy that starts with a set of random nodes and then performs a random walk through a chain of neighbors reliably provides early warnings without requiring prior knowledge of the network. We find this method, called “random chain”, to be the most pragmatic for implementation in a real-world disease surveillance context.

60 APPLIED LIFE SCIENCES↗
NASA NTRS2011

Application of the Life Safety Code to a Historic Test Stand

NASA has conducted a study to assess alternatives to refurbishing existing launch vehicle modal test facilities as opposed to developing new test facilities to meet the demands of a very fiscally constrained test and evaluation environment. The results of this study showed that Marshall Space Flight Center (MSFC) Test Stand (TS) 4550 could be made compliant, within reasonable cost and schedule impacts, if safety processes and operational limitations were put in place to meet the safety codes and concerns of the Fire Marshall. Trades were performed with key selection criteria to ensure that appropriate levels of occupant safety are incorporated into test facility design modifications. In preparation for the ground vibration tests that were to be performed on the Ares I launch vehicle, the Ares Flight and Integrated Test Office (FITO) organization evaluated the available test facility options, which included the existing mothballed structural dynamic TS4550 used by Apollo and Shuttle, alternative ground vibration test facilities at other locations, and construction of a new dynamic test stand. After an exhaustive assessment of the alternatives, the results favored modifying the TS4550 because it was the lowest cost option and presented the least schedule risk to the NASA Constellation Program for Ares Integrated Vehicle Ground Vibration Test (IVGVT). As the renovation design plans and drawings were being developed for TS4550, a safety concern was discovered the original design for the construction of the test stand, originally built for the Apollo Program and renovated for the Shuttle Program, was completed before NASA s adoption of the currently imposed safety and building codes per National Fire Protection Association Life Safety Code [NFPA 101] and International Building Codes. The initial FITO assessment of the design changes, required to make TS4550 compliant with current safety and building standards, identified a significant cost increase and schedule impact. An effort was launched to thoroughly evaluate the applicable life safety requirements, examine the context in which they were derived, and determine a means by which the TS4550 modifications could be made within budget and on schedule, while still providing the occupants with appropriate levels of safety.

Askins, Bruce↗
NASA NTRS1984

Joined-wing research airplane feasibility study

The joined wing is a new type of aircraft configuration which employs tandem wings arranged to form diamond shapes in plan view and front view. Wind-tunnel tests and finite-element structural analyses have shown that the joined wing provides the following advantages over a comparable wing-plus-tail system; lighter weight and higher stiffness, higher span-efficiency factor, higher trimmed maximum lift coefficient, lower wave drag, plus built-in direct lift and direct sideforce control capability. To verify these advantages at full scale a manned research airplane is required. A study has therefore been performed of the feasibility of constructing such an airplane, using the fuselage and engines of the existing NAA AD-1 oblique-wing airplane. Cost and schedule constraints favored converting the AD-1 rather than constructing a totally new airframe. By removing the outboard wing panels the configuration can simulate wings joined at 60, 80, or 100 percent of span. For maximum versatility the aircraft has alternative control surfaces (such as ailerons and elevators on the front and/or rear wings), and a removeable canard to explore canard/joined-wing interactions at high-lift conditions. Design, performance, and flying qualities are discussed.

Wolkovitch, J.↗
DOE OSTI2024

Impacts of Model Building Energy Codes

The Department of Energy (DOE) Building Energy Codes Program (BECP) periodically evaluates national and state-level impacts associated with energy codes in residential and commercial buildings. Pacific Northwest National Laboratory (PNNL), funded by DOE, conducted an assessment of the prospective impacts of national model building energy codes from 2010 through 2040. A previous PNNL study evaluated the impact of the Building Energy Codes Program. A 2016 study looked more broadly at overall code impacts and this report describes the methodology used for the assessment and presents the impacts in terms of energy savings, consumer cost savings, and reduced emissions at the state level and at aggregated levels. In 2021, DOE conducted an interim and limited update to its 2016 study to evaluate potential building code updates using the 2016 methodology. That interim update includes estimated savings resulting from updates to the model energy codes, including the ANSI/ASHRAE/IES Standard 90.1-2016 (ASHRAE 90.1-2016) and 2019 editions, as well as the 2018 and 2021 International Energy Conservation Code (IECC). In 2023, DOE developed a fully updated report that includes code updates (ASHRAE 90.1-2019 and 2021 IECC), as well as additional enhancements and updates, including updated energy prices, annual floorspace additions, state code adoption dates, and emission factors, among others. This current version is another fully updated report that includes code updates (ASHRAE 90.1-2022 and 2024 IECC), as well as additional enhancements and updates, including updated energy prices, state code adoption dates, emission factors, and renewable energy contribution among others. Energy codes follow a three-phase cycle that starts with the development of a new model code, proceeds with the adoption of the new code by states and local jurisdictions, and finishes when the new code is implemented and builders, architects, and engineers are required to comply with the new provisions. The development of new model code editions creates the potential for increased energy savings. After a new model code is adopted, potential savings are realized in the field when new buildings (or additions and alterations) are constructed to comply with the new code. The contributions of all three phases are crucial to the overall impact of codes and are considered in this assessment. Figure ES.1 schematically describes the analysis framework. Energy savings are expressed in terms of energy use intensity (EUI) in the figure.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
NASA NTRS1991

Structured background grids for generation of unstructured grids by advancing front method

A new method of background grid construction is introduced for generation of unstructured tetrahedral grids using the advancing-front technique. Unlike the conventional triangular/tetrahedral background grids which are difficult to construct and usually inadequate in performance, the new method exploits the simplicity of uniform Cartesian meshes and provides grids of better quality. The approach is analogous to solving a steady-state heat conduction problem with discrete heat sources. The spacing parameters of grid points are distributed over the nodes of a Cartesian background grid by interpolating from a few prescribed sources and solving a Poisson equation. To increase the control over the grid point distribution, a directional clustering approach is used. The new method is convenient to use and provides better grid quality and flexibility. Sample results are presented to demonstrate the power of the method.

Pirzadeh, Shahyar↗
NASA NTRS2010

World Wide Web Metaphors for Search Mission Data

A software program that searches and browses mission data emulates a Web browser, containing standard meta - phors for Web browsing. By taking advantage of back-end URLs, users may save and share search states. Also, since a Web interface is familiar to users, training time is reduced. Familiar back and forward buttons move through a local search history. A refresh/reload button regenerates a query, and loads in any new data. URLs can be constructed to save search results. Adding context to the current search is also handled through a familiar Web metaphor. The query is constructed by clicking on hyperlinks that represent new components to the search query. The selection of a link appears to the user as a page change; the choice of links changes to represent the updated search and the results are filtered by the new criteria. Selecting a navigation link changes the current query and also the URL that is associated with it. The back button can be used to return to the previous search state. This software is part of the MSLICE release, which was written in Java. It will run on any current Windows, Macintosh, or Linux system.

Norris, Jeffrey S.↗
NASA NTRS2001

BNL accelerator-based radiobiology facilities

For the past several years, the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory (USA) has provided ions of iron, silicon and gold, at energies from 600 MeV/nucleon to 10 GeV/nucleon, for the US National Aeronautics and Space Administration (NASA) radiobiology research program. NASA has recently funded the construction of a new dedicated ion facility, the Booster Applications Facility (BAF). The Booster synchrotron will supply ion beams ranging from protons to gold, in an energy range from 40-3000 MeV/nucleon with maximum beam intensities of 10(10) to 10(11) ions per pulse. The BAF Project will be described and the future AGS and BAF operation plans will be presented.

NASA Discipline Radiation Health↗
DOE OSTI2020

Locally adaptive artificial viscosity strategies for Lagrangian hydrodynamics

To accurately model inviscid flow with shock waves using staggered-grid Lagrangian hydrodynamics, artificial viscosity is introduced to convert kinetic energy into internal energy, thereby providing a mechanism to generate the required entropy increase across shocks. In this paper, we propose a new method for constructing an adaptive, artificial viscosity in the context of one-dimensional, staggered-grid Lagrangian hydrodynamics. Our adaptive, artificial viscosity is defined in terms of two parameters that depend on density locally in a neighborhood around a shock, and hence, vary cell-by-cell. Our methodology is based on building a reference set of pre-computed optimal, globally constant artificial viscosity coefficients for a family of isolated shock test problems. For arbitrary flows, the evaluation of the unknown coefficients is automated by first estimating shock intensity locally, and second computing the corresponding adaptive parameter value via interpolation over the data from the pre-computed reference set of optimal, globally constant coefficient values. To illustrate the performance of our new approach, we compare our results against two existing methods. The first method is a limiter-based approach, which relies on estimating velocity gradients of the flow, and the second method is utilized in several commercial codes. Finally, we demonstrate that our new adaptive methodology produces more accurate results for a variety of tests with propagating shock waves, as well as for the aforementioned family of isolated shock problems.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS1995

Basic space payload fastener

A new basic space fastener has been developed and tested by the GSFC. The purposes of this fastener are to permit assembly and servicing in space by astronauts and/or robots and to facilitate qualification of payloads on Earth prior to launch by saving time and money during the systems integration and component testing and qualification processes. The space fastener is a rework of the basic machine screw such that crossthreading is impossible; it is self-locking and will not work its way out during launch (vibration proof); it will not wear out despite repeated use; it occupies a small foot print which is comparable to its machine screw equivalent, and it provides force and exhibits strength comparable to its machine screw equivalent. Construction is ultra-simple and cost effective and the principle is applicable across the full range of screw sizes ranging from a #10 screw to 2.5 cm (1 in) or more. In this paper, the fastener principles of operation will be discussed along with test results and construction details. The new fastener also has considerable potential in the commercial sector. A few promising applications will be presented.

Vranish, J. M.↗
DOE OSTI2022

Bioinspired Macrocyclic Molecule Supported Two‐Dimensional Lamellar Membrane with Robust Interlayer Structure for High‐Efficiency Nanofiltration

Abstract 2D lamellar membranes (2DLMs) are used for efficient desalination and nanofiltration. However, weak interactions between adjacent stacked nanosheets result in susceptibility to swelling that limits practical applicability. Inspired by the super adhesion of multi‐point suction cups on octopus tentacles, a 2DLM is constructed from Ti 3 C 2 T x MXene supported by the macrocyclic “multi‐point” molecule cucurbit[5]uril (CB5) and demonstrated for nanofiltration of methyl blue (MB) and enrichment of uranyl carbonate. Experimental results and density functional theory calculations indicate that CB5 rivets to the surface of the nanoflakes through strong stable interactions between its multiple binding sites and surface hydroxyl functional groups on MXene nanosheets. This novel 2DLM exhibits excellent nanofiltration performance (69 L m −2 h −1 bar −1 permeance with 93.6% rejection for MB) and can be recycled at least 30 times without significant degradation. The 2DLM exhibits excellent swelling resistance at high salinity, with a demonstration of selective enrichment of uranyl carbonate from artificial water and natural seawater. The results provide a new strategy for constructing highly stable 2DLMs with interlayer spacing controllable from sub‐nano to nanometer scales, for size‐selective sieving of molecules and ions, high‐efficiency nanofiltration, and other applications.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2022

Improved Cost Estimates to Boost Pumped Storage Hydropower Construction

Pumped storage hydropower is often overlooked in future grid planning efforts, in part because the cost to build a new facility is not always clear. That's why the National Renewable Energy Laboratory (NREL), along with the U.S. Department of Energy's Water Power Technologies Office, is developing improved cost estimates and cost models to reduce that uncertainty and give developers the data they need to decide where and when to construct new PSH facilities to support the country's evolving energy grid.

ENERGY PLANNING, POLICY, AND ECONOMY,HYDRO ENERGY↗