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At least 469 records · Page 26

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DOE OSTI2024

Submerged Fatigue Testing of Marine Energy Advanced Materials

Marine energy structures are typically made of advanced composite materials and are subjected to extreme ocean environments in service. In extreme ocean environments, seawater currents and waves load structures repeatedly, which cause two environmental conditions: water intrusion and mechanical fatigue. In prior research, the two environmental conditions were applied sequentially, where composite specimens were aged and then mechanically tested. To understand the combined effects of dynamic loading and water intrusion on composite materials, the present study involves the static and fatigue four-point bend testing of composite coupons in a water tank. The water tank was designed and built to fit either a 100 kN or a 250 kN load frame. Flexural strength value, cycles to failure, and failure mode results from submerged fatigue testing will be used to inform marine energy structure designs. The coupon-scale test method will be used to scale up to and inform methods for subsequent subcomponent testing and standards development. Finally, the benefits of designing marine energy structures to informed standards are decreased lifetime costs and increased reliability and energy production, ultimately leading to a sustainable and low-carbon energy system.

13 HYDRO ENERGY↗

NASA NTRS1991

System reliability approaches for advanced propulsion system structures

This paper identifies significant issues that pertain to the estimation and use of system reliability in the design of advanced propulsion system structures. Linkages between the reliabilities of individual components and their effect on system design issues such as performance, cost, availability, and certification are examined. The need for system reliability computation to address the continuum nature of propulsion system structures and synergistic progressive damage modes has been highlighted. Available system reliability models are observed to apply only to discrete systems. Therefore a sequential structural reanalysis procedure is formulated to rigorously compute the conditional dependencies between various failure modes. The method is developed in a manner that supports both top-down and bottom-up analyses in system reliability.

Cruse, T. A.↗

NASA NTRS2016

Concept Study for a Compact Planetary Homodyne Interferometer (PHI) for Temporal Global Observation of Methane on Mars in IR

We present a concept study to develop a new instrument to sequentially and over a long time measure methane abundance on Mars and find out its global seasonal variations, if any. The Planetary Homodyne Interferometer (PHI) can offer integrated spectra over a wide field-of-view (FOV) in high spectral resolution (R~10(exp 5)) in a compact design using no (or a small < 1m) primary mirror. PHI is best suited to studies of sources where temporally tracing specific spectral features sensitivity, and spectral resolution is of higher significance than spatial fidelity.

Extended targets↗

DOE OSTI2024

Submerged Fatigue Testing of Marine Energy Advanced Materials: Preprint

Marine energy structures are typically made of advanced composite materials and are subjected to extreme ocean environments in service. In extreme ocean environments, seawater currents and waves load structures repeatedly, which cause two environmental conditions: water intrusion and mechanical fatigue. In prior research, the two environmental conditions were applied sequentially, where composite specimens were aged and then mechanically tested. To understand the combined effects of dynamic loading and water intrusion on composite materials, the present study involves the static and fatigue four-point bend testing of composite coupons in a water tank. The water tank was designed and built to fit either a 100 kN or a 250 kN load frame. Flexural strength value, cycles to failure, and failure mode results from submerged fatigue testing will be used to inform marine energy structure designs. The coupon-scale test method will be used to scale up to and inform methods for subsequent subcomponent testing and standards development. The benefits of designing marine energy structures to informed standards are decreased lifetime costs and increased reliability and energy production, ultimately leading to a sustainable and low-carbon energy system.

composite materials↗

DOE OSTI2024

Submerged Fatigue Testing of Marine Energy Advanced Materials

Marine energy structures are typically made of advanced composite materials and are subjected to extreme ocean environments in service. In extreme ocean environments, seawater currents and waves load structures repeatedly, which cause two environmental conditions: water intrusion and mechanical fatigue. In prior research, the two environmental conditions were applied sequentially, where composite specimens were aged and then mechanically tested. To understand the combined effects of dynamic loading and water intrusion on composite materials, the present study involves the static and fatigue four-point bend testing of composite coupons in a water tank. The water tank was designed and built to fit either a 100 kN or a 250 kN load frame. Flexural strength value, cycles to failure, and failure mode results from submerged fatigue testing will be used to inform marine energy structure designs. The coupon-scale test method will be used to scale up to and inform methods for subsequent subcomponent testing and standards development. The benefits of designing marine energy structures to informed standards are decreased lifetime costs and increased reliability and energy production, ultimately leading to a sustainable and low-carbon energy system.

composite materials↗

DOE OSTI2024

Non-Intrusive Parallel-in-Time Solvers for Partial Differential Equations (Final Report)

Many time-dependent problems and simulations are often modeled using Partial Differential Equations. Traditional modeling approaches that use sequential time-stepping are reaching a bottleneck in optimizing efficiency. The Center of Applied Science and Computing at Lawrence Livermore National Laboratory extensively works on parallelizing these algorithms to leverage the increasing computational power from the growing number of processors in computer hardware. In particular, they aim to design non-intrusive algorithms that can generalize to a variety of problems and sizes without requiring additional information from or modifications on the original problems. Multigrid Reduction in Time (MGRIT) is a parallel-in-time algorithm that is designed to be non-intrusive. This project focuses on increasing the efficiency of MGRIT by approximating the coarse-grid operator using machine learning approaches as a means to find the most non-intrusive, or general, solution.

97 MATHEMATICS AND COMPUTING↗

NASA NTRS1978

The WX-32193, a new 70 mm SEC image tube for astronomical application

The new SEC image camera tube is designed for astronomical application. Its large target allows a wide viewing angle with excellent resolution and little distortion, as the tube is magnetically focussed. The target is able to store information over several days and with proper cooling integration of weak light signals is possible over several hours. A sequential writing - reading slow scan mode is suggested for most effective application. The window is transmissive far into the vacuum UV-spectrum. Zooming with a fourfold magnification has been successfully demonstrated employing a magnetic lens in front of the image section. The tube construction is ruggedized to withstand the shock and vibration requirements of rocket launch.

Pietrzyk, J. P.↗

NASA NTRS1983

The SETI Interpreter Program (SIP). a Software Package for the SETI Field Tests

The SETI (Search for Extraterrestrial Intelligence) Interpreter Program (SIP) is an interactive software package designed to allow flexible off line processing of the SETI field test data on a PDP 11/44 computer. The user can write and immediately execute complex analysis programs using the compact SIP command language. The software utilized by the SETI Interpreter Program consists of FORTRAN - coded modules that are sequentially installed and executed.

Olsen, E. T.↗

DOE OSTI2024

Dynamic Multiplexed Control and Modeling of Optogenetic Systems Using the High-Throughput Optogenetic Platform, Lustro

The ability to control cellular processes using optogenetics is inducer-limited, with most optogenetic systems responding to blue light. To address this limitation, we leverage an integrated framework combining Lustro, a powerful high-throughput optogenetics platform, and machine learning tools to enable multiplexed control over blue light-sensitive optogenetic systems. Specifically, we identify light induction conditions for sequential activation as well as preferential activation and switching between pairs of light-sensitive split transcription factors in the budding yeast, Saccharomyces cerevisiae. We use the high-throughput data generated from Lustro to build a Bayesian optimization framework that incorporates data-driven learning, uncertainty quantification, and experimental design to enable the prediction of system behavior and the identification of optimal conditions for multiplexed control. This work lays the foundation for designing more advanced synthetic biological circuits incorporating optogenetics, where multiple circuit components can be controlled using designer light induction programs, with broad implications for biotechnology and bioengineering.

59 BASIC BIOLOGICAL SCIENCES↗

NASA NTRS2004

The Biotechnology Facility for International Space Station

The primary mission of the Cellular Biotechnology Program is to advance microgravity as a tool in basic and applied cell biology. The microgravity environment can be used to study fundamental principles of cell biology and to achieve specific applications such as tissue engineering. The Biotechnology Facility (BTF) will provide a state-of-the-art facility to perform cellular biotechnology research onboard the International Space Station (ISS). The BTF will support continuous operation, which will allow performance of long-duration experiments and will significantly increase the on-orbit science throughput. With the BTF, dedicated ground support, and a community of investigators, the goals of the Cellular Biotechnology Program at Johnson Space Center are to: Support approximately 400 typical investigator experiments during the nominal design life of BTF (10 years). Support a steady increase in investigations per year, starting with stationary bioreactor experiments and adding rotating bioreactor experiments at a later date. Support at least 80% of all new cellular biotechnology investigations selected through the NASA Research Announcement (NRA) process. Modular components - to allow sequential and continuous experiment operations without cross-contamination Increased cold storage capability (+4 C, -80 C, -180 C). Storage of frozen cell culture inoculum - to allow sequential investigations. Storage of post-experiment samples - for return of high quality samples. Increased number of cell cultures per investigation, with replicates - to provide sufficient number of samples for data analysis and publication of results in peer-reviewed scientific journals.

Goodwin, Thomas↗

NASA NTRS2006

User-Defined Data Distributions in High-Level Programming Languages

One of the characteristic features of today s high performance computing systems is a physically distributed memory. Efficient management of locality is essential for meeting key performance requirements for these architectures. The standard technique for dealing with this issue has involved the extension of traditional sequential programming languages with explicit message passing, in the context of a processor-centric view of parallel computation. This has resulted in complex and error-prone assembly-style codes in which algorithms and communication are inextricably interwoven. This paper presents a high-level approach to the design and implementation of data distributions. Our work is motivated by the need to improve the current parallel programming methodology by introducing a paradigm supporting the development of efficient and reusable parallel code. This approach is currently being implemented in the context of a new programming language called Chapel, which is designed in the HPCS project Cascade.

physically distributed memory↗

NASA NTRS2007

Development of the Functional Flow Block Diagram for the J-2X Rocket Engine System

The J-2X program calls for the upgrade of the Apollo-era Rocketdyne J-2 engine to higher power levels, using new materials and manufacturing techniques, and with more restrictive safety and reliability requirements than prior human-rated engines in NASA history. Such requirements demand a comprehensive systems engineering effort to ensure success. Pratt & Whitney Rocketdyne system engineers performed a functional analysis of the engine to establish the functional architecture. J-2X functions were captured in six major operational blocks. Each block was divided into sub-blocks or states. In each sub-block, functions necessary to perform each state were determined. A functional engine schematic consistent with the fidelity of the system model was defined for this analysis. The blocks, sub-blocks, and functions were sequentially numbered to differentiate the states in which the function were performed and to indicate the sequence of events. The Engine System was functionally partitioned, to provide separate and unique functional operators. Establishing unique functional operators as work output of the System Architecture process is novel in Liquid Propulsion Engine design. Each functional operator was described such that its unique functionality was identified. The decomposed functions were then allocated to the functional operators both of which were the inputs to the subsystem or component performance specifications. PWR also used a novel approach to identify and map the engine functional requirements to customer-specified functions. The final result was a comprehensive Functional Flow Block Diagram (FFBD) for the J-2X Engine System, decomposed to the component level and mapped to all functional requirements. This FFBD greatly facilitates component specification development, providing a well-defined trade space for functional trades at the subsystem and component level. It also provides a framework for function-based failure modes and effects analysis (FMEA), and a rigorous baseline for the functional architecture.

White, Thomas↗

DOE OSTI2026

Engineering Structural Transitions in a Multilevel Molecular Switch via Intermolecular Coupling

Controlling molecular conformations with atomic precision is essential for advancing molecular functional electronics, as well as our understanding of molecular dynamics. While switching between bistable molecular conformers is common in nature, creating systems with multiple, addressable states remains synthetically challenging. Here, we demonstrate a bottom-up strategy in which intermolecular interactions give rise to multilevel functionality within a simple two-molecule assembly. Using low-temperature scanning tunneling microscopy, we show that a pyrrolidine dimer on Cu(100) exhibits six distinct adsorption conformations, exceeding the four expected from two independent bistable units. This unusual complexity arises from the interplay between intermolecular van der Waals attraction and steric repulsion, which reshapes the potential energy landscape and changes a single high-energy transition into a sequential two-step pathway. Each step is driven by low-energy inelastic electron excitations, achieving a switching efficiency an order of magnitude higher than that of the monomer. Here, by tuning the bias voltage and tip–molecule distance, we achieve deterministic control over multiple stable states, establishing a general design principle for on-demand engineering of collective molecular behavior and energy-efficient multilevel molecular devices.

Molecular interactions↗

DOE OSTI2025

Geochemical Impact of Acid Spearhead and Slickwater Stimulation on Wolfcamp Shale from the Hydraulic Fracturing Test Site

The Hydraulic Fracturing Test Site 1 (HFTS-1) was a field study performed in the Wolfcamp Formation in the West Texas Permian (Midland) Basin, USA, with a focus on improving the efficiency of hydraulic fracturing. Investigating site-specific rock-fluid geochemical interactions during hydraulic fracturing is an important step to understanding the impact on formation shale porosity, permeability, and long-term shale gas production. During field operations in this region, hydraulic fracturing fluid (HFF) injection usually starts with a concentrated acid spearhead for rapid rock dissolution, followed by the injection of near-neutral pH slickwater containing chemicals and proppants. A multistep sequential injection approach was used to investigate different stages of rock-fluid interactions. The carbonate content in the host rock is important when acid spearhead is considered, as carbonate mineral dissolution is rapid and can result in porosity and permeability changes in the shale matrix. Here, in this study, we designed flow-through experiments using fractured carbonate-rich and clay-rich Wolfcamp shale cores with (1) a short-time acid soaking step and (2) a long-term slickwater flow-through step to simulate the injection method used at HFTS-1. The fluid chemistry was analyzed. A thorough mineralogical progression [e.g., Calcium (Ca) dissolution and iron (Fe) redox progression] in the cores during HFF injection was also characterized and imaged by synchrotron microprobe. Reactive transport modeling was performed based on the experimental setup. The results showed that the acid spearhead is a crucial step in creating a reaction front by mineral dissolution, especially in carbonate-rich shales. A slight layer of ferrihydrite precipitated during the slickwater flow-through period. This study provides insights into potential geochemical impact due to hydraulic fracturing operations in the Permian Basin.

clastic rock↗

DOE OSTI2024

Liquid Piston with Spray Cooling Near-Isothermal Compressor

The goal of this project was to prototype and characterize the performance of a liquid-piston spray-cooled gas compressor. The working principle of the compressor enables optimized high-efficiency operation over a very wide range of operating conditions, unlike conventional compressors that are optimized for a narrow range of operating conditions. The compressor technology is suitable for many applications, such as gas pipeline transport, gas storage, and commercial and residential heat pumps. Both physical testing and computational fluid dynamics (CFD) modeling of the processes using the Oak Ridge National Laboratory high-performance computing center were completed. The experimental and CFD studies focused on a near-isothermal liquid-piston compressor (LPC) that uses propylene glycol to compress CO 2 . The first prototype demonstrated isothermal operation during several sequentially executed cycles of CO 2 compression and raised the temperature of the compressed CO 2 by only 2 K, compared with approximately 6 K when the gas was compressed non-isothermally. Isothermal operation was demonstrated at CO 2 flow rates of up to 2 L/min. The second prototype was designed with two compression chambers to allow continuous flow of high-pressure CO 2 . However, the design of the valve train to direct flow between the compression chambers was not sufficient to allow demonstration of CO 2 compression. Numerical simulations of the LPC in which the compression chamber was filled with propylene glycol injected from the bottom inlet were performed using large eddy simulation (LES) with the wall-adapting local eddy-viscosity subgrid-scale model coupled with the multiphase volume of fluid (VOF) model to simulate the transient interface between gas and liquid and to capture the heat and mass transfers within the compression chamber. In this effort, the effects of boundary conditions applied to the LES-VOF calculations (i.e., no wall, an adiabatic wall, and a wall with a heat flux subscribed) on the overall pressure and temperature of the CO 2 gas as well as the transient evolution of flow and heat transfer within the compression chamber were investigated and are discussed in this report. The LES calculation with no wall showed no dynamical flow patterns, and the volume-averaged temperature of CO 2 increased from 305 to 392.7 K, whereas LES calculations with a constant wall temperature or a wall heat flux had similar increases of CO 2 temperatures. The results of the LES simulation using a wall heat flux showed different stages in the compression process and revealed dynamical formation and interaction of CO 2 gas layers and circulation flow patterns within the chamber that contributed to the overall heat transfer between the solid wall, gas, and liquid surface in the compressor. Though an industrial partnership for commercializing the compressor was not secured, the technology was attractive for an industrial partner to use in two research proposals in response to US Department of Energy funding opportunity announcements.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

NASA NTRS1992

A 20 MHz CMOS reorder buffer for a superscalar microprocessor

Superscalar processors can achieve increased performance by issuing instructions out-of-order from the original sequential instruction stream. Implementing an out-of-order instruction issue policy requires a hardware mechanism to prevent incorrectly executed instructions from updating register values. A reorder buffer can be used to allow a superscalar processor to issue instructions out-of-order and maintain program correctness. This paper describes the design and implementation of a 20MHz CMOS reorder buffer for superscalar processors. The reorder buffer is designed to accept and retire two instructions per cycle. A full-custom layout in 1.2 micron has been implemented, measuring 1.1058 mm by 1.3542 mm.

Lenell, John↗

NASA NTRS1996

Magnetospheric Atmospheric X-ray Imaging Experiment (MAXIE)

This report summarizes the activities sponsored by the Office of Naval Research for the Magnetospheric Atmospheric X-ray Imaging Experiment (MAXIE). The MAXIE instrument was developed as a joint activity of Lockheed, The Aerospace Corporation, and the University of Bergen, Norway. Lockheed was responsible for the overall management of the program, interfacing with the appropriate government agencies, the overall electrical and mechanical design, flight software, environmental testing, spacecraft integration activities, on orbit checkout, and data processing activities. The Magnetospheric Atmospheric X-ray Imaging Experiment (MAXIE), the ONR 401 experiment, is the first in a new class of satellite-borne remote sensing instruments. The primary innovation is the ability to obtain rapid, sequential, images with high sensitivity of the earth's X ray aurora from a low altitude polar orbiting satellite. These images can be used to identify dynamic temporal variations in the three-dimensional (energy and position) distribution of electron precipitation into the atmosphere. MAXIE was launched on the TIROS NOAA-13 satellite on 9 August 1993. The experiment performed well during its turn-on sequence; however, the spacecraft bus failed on 21 August 1993. New spacebased technologies successfully used in MAXIE were mixed-mode ASIC microcircuits, a zero torque scanning system with associated viscoelastic damping, a paraffin stow release mechanism, a parallel integrating PHA processor, a low noise Si(Li) sensor telescope, and an advanced thermal cooling system. MAXIE's on orbit operation, control of penetrating particle backgrounds, and scientific data indicated good overall performance.

Imhof, W. L.↗

NASA NTRS2002

Preliminary Optimal Orbit Design for the Laser Interferometer Space Antenna (LISA)

In this paper we present a preliminary optimal orbit analysis for the Laser Interferometer Space Antenna (LISA). LISA is a NASA/ESA mission to study gravitational waves and test predictions of general relativity. The nominal formation consists of three spacecraft in heliocentric orbits at 1 AU and trailing the Earth by twenty degrees. This configuration was chosen as a trade off to reduce the noise sources that will affect the instrument and to reduce the fuel to achieve the final orbit. We present equations for the nominal orbit design and discuss several different measures of performance for the LISA formation. All of the measures directly relate the formation dynamics to science performance. Also, constraints on the formation dynamics due to spacecraft and instrument limitations are discussed. Using the nominal solution as an initial guess, the formation is optimized using Sequential Quadratic Programming to maximize the performance while satisfying a set of nonlinear constraints. Results are presented for each of the performance measures.

Hughes, Steven P.↗