Exploration of reduced graphene oxide microparticles as electrocatalytic materials in vanadium redox flow batteries
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Alazmi, Amira↗
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Results for “Critical Step”
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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Polymer/Regolith Composites for In-Space Manufacturing on the Moon and Mars
In-Space Manufacturing (ISM) is vital to supporting a sustained human presence on the Moon or Mars. With payload launch prices ranging from $4,000 to more than $1 million per kg, reducing payload mass is of critical interest. Using in-situ resources for ISM is particularly attractive as it allows for a system of Earth-independent manufacturing for the Lunar surface, reducing the initial payload mass that is required for current ISM systems that rely on terrestrially synthesized materials. This talk presents new composite materials made from Lunar and Martian regolith and Poly(3-hydroxybutyrate) (PHB), a thermoplastic that offers the ability to be biosynthesized in space using various in-situ resources like organic waste or atmospheric CO2 as feedstock. The addition of regolith provides a route to creating materials with a diverse set of properties which will be discussed. The development of these materials represents the first step in creating a system of closed-loop ISM, which is critical to establishing a lasting human presence in space.
In-situ resource utilization↗
Biosynthesized Thermoplastic/Regolith Composites for Closed-Loop In-Space Manufacturing
In-Space Manufacturing (ISM) is vital to supporting a sustained human presence on the Moon or Mars. With payload launch prices ranging from $4,000 to more than $1 million per kg, reducing payload mass is of critical interest. Using in-situ resources for ISM is particularly attractive as it allows for a system of Earth-independent manufacturing for the Lunar surface, reducing the initial payload mass that is required for current ISM systems that rely on terrestrially synthesized materials. This talk presents new composite materials made from Lunar and Martian regolith and Poly(3-hydroxybutyrate) (PHB), a thermoplastic that offers the ability to be biosynthesized in space using various in-situ resources like organic waste or atmospheric CO2 as feedstock. The addition of regolith provides a route to creating materials with a diverse set of properties which will be discussed. The development of these materials represents the first step in creating a system of closed-loop ISM, which is critical to establishing a lasting human presence in space.
In situ resource utilization↗
Evaluation of HCF strength of Alloy 625 with non-optimum additive manufacturing process parameters
An extensive experimental program was undertaken to generate the process-structure-HCF property data for additive-manufactured Alloy 625. Round tensile and flat dog-bone HCF specimens were fabricated using a laser powder bed fusion process. Several builds were fabricated with different processing parameters. The fatigue strengths were determined using a step-test method and fracture surfaces were characterized to identify the critical microstructure feature associated with the formation of the fatigue crack. Finally, a fracture mechanics-based methodology using fatigue crack growth data measured on a wrought alloy is shown to provide conservative estimates of the HCF lives for the additive-manufactured alloy.
36 MATERIALS SCIENCE↗
Design and Implementation of Automated Characterization of T-type based Power Module for PV Inverter Reliability Assessment
Reliability of power electronics holds the key for future power and energy systems since it is essential for system integration with renewables and energy storage systems. Variation of power module characteristics over the converter’s operational lifetime is a critical indicator to assess its reliability. Device characterization consists of different steps to collect, process, and visualize results, which is usually time-consuming, especially for power modules based on a non-phase-leg configuration, such as T-type circuits, widely applied for PV inverters. To reduce the time, ensure repeatability, and guarantee consistency, an automated test bench can be helpful. This paper focuses on a T-type-based power module and proposes a unique characterization platform and corresponding automation procedure and implementation. Considering the major characterization difference between T-type power modules over the conventional phase-leg power module, first, the special consideration for static characterization is highlighted. Second, the unique dynamic characterization design associated with the T-type power module is described. Finally, the automation of the power module characterization and the test platform is presented along with results and special considerations.
Siraj, Ahmed↗
Data processing methods and data acquisition for samples larger than the field of view in parallel-beam tomography
Parallel-beam tomography systems at synchrotron facilities have limited field of view (FOV) determined by the available beam size and detector system coverage. Scanning the full size of samples bigger than the FOV requires various data acquisition schemes such as grid scan, 360-degree scan with offset center-of-rotation (COR), helical scan, or combinations of these schemes. Though straightforward to implement, these scanning techniques have not often been used due to the lack of software and methods to process such types of data in an easy and automated fashion. The ease of use and automation is critical at synchrotron facilities where using visual inspection in data processing steps such as image stitching, COR determination, or helical data conversion is impractical due to the large size of datasets. Here, we provide methods and their implementations in a Python package, named Algotom, for not only processing such data types but also with the highest quality possible. The efficiency and ease of use of these tools can help to extend applications of parallel-beam tomography systems.
36 MATERIALS SCIENCE↗
From Interstellar Cloud to Star to Laboratory: Frontier HEDP Studies of Magnetized Colliding Plasma Flows with Strong Radiative Cooling (Final Report)
High-speed flows of gas are the norm in astrophysics where exploding stars, winds from the regions around black holes and streams of galactic material create “supersonic flows”. As the flows collide, strong shock waves are formed where gas is compressed and heated. The regions behind these shock waves are of great interest to scientists. New stars can form in these shock regions in the context of galaxies. In the context of planets like our Earth, the shocks waves come from the interaction of the solar wind with our planets’ magnetic field causing Aurora and placing astronauts and satellites in jeopardy. Thus, understanding supersonic flows of magnetized plasmas is essential for progress in many fields of astronomy and space physics (relevant to planets and the Earth). Remarkably, we can also create these kinds of flows in the laboratory using Z-pinches and laser driven experiments that include magnetic fields. The exploration of these forms of “High Energy Density Physics” (HEDP) flows is also critical in order to achieve Inertial Confinement Fusion, which is a step towards developing a sustainable source of Fusion energy.
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
CCE Phase 1: Consequence Prioritization
Idaho National Laboratory (INL) developed the Consequence-driven Cyber-informed Engineering (CCE) methodology to provide public and private organizations with steps to work collaboratively and establish a working relationship to protect critical infrastructure and other national assets. This process is a considerable undertaking, iterative in nature, and—as time and resources allow—should become a part of a company’s culture. By focusing on the impact of potentially negative Events, CCE provides a better understanding of how and why adversaries can affect critical functions and services using cyber-enabled sabotage. This document describes Phase 1 of the CCE process.
99 GENERAL AND MISCELLANEOUS↗
Interparticle Characterization of Mechanical Biomass Particle-Particle and Particle-Wall Interactions
The biomass materials industry faces significant challenges in managing material variability and its impact on storage and handling systems. Physical properties such as moisture content, particle size, and density fluctuate considerably, leading to operational issues like bridging and ratholing that disrupt material flow. These variations create a complex cascade effect throughout the process chain, affecting transportation, storage, and conversion processes. The economic consequences of this variability manifest in increased operational costs, maintenance requirements, and system downtime. Environmental factors further complicate the situation, as weather conditions and seasonal availability influence material properties and system performance. Engineers employ specialized equipment design, material characterization protocols, and pre-processing steps like size reduction and homogenization to address these challenges. A critical knowledge gap exists between continuous-level constitutive models and particle-scale behavior. This project developed a novel device to quantify interparticle mechanics between biomass particles, measuring friction and adhesion forces between particles and wall materials. The research focused on corn stover and southern pine forest residue, creating a comprehensive database of particle interactions. This breakthrough enables direct application in particle-based computational modeling, advancing the field's understanding of biomass handling characteristics and supporting the development of more reliable and efficient storage and handling systems. The project's outcomes contribute significantly to understanding biomass's mechanical and flow characteristics, particularly how variability at the particle level affects larger-scale handling operations. This knowledge is crucial for engineering feedstock supply systems that consistently meet quality and cost specifications for various conversion processes. The innovative experimental setup developed through this research represents a significant advancement in biomass characterization methodology. Providing precise measurements of particle-level interactions establishes a foundation for more accurate predictive modeling of bulk material behavior. This enhanced understanding of fundamental particle mechanics enables engineers to anticipate better and address handling challenges before they manifest in full-scale operations. This research opens new avenues for optimizing biomass handling systems through data-driven design approaches. The comprehensive database of particle interactions serves as a valuable resource for future research and development efforts, potentially leading to more efficient and cost-effective biomass processing solutions. This advancement in particle-level mechanics could revolutionize how biomass handling systems are designed and operated, contributing to more sustainable and reliable renewable energy production.
09 BIOMASS FUELS↗
Manganese bismuth films with narrow transfer characteristics for Curie-point switching
Manganese bismuth films having improved characteristics for recording information in analogue form, can be produced by a vacuum deposition of Bi and Mn with an atomic ratio of Mn to Bi between 2 and 3.5 or 1.4 and 1.6, followed by a specialized heat treatment which includes very brief exposure to a temperature between about 275 deg and 300 C. Similar MnBi films can be produced more reliably and reproducibly if the initial Bi layer is annealed prior to deposition of the Mn layer. Such an annealing step renders most other factors of the processing relatively non-critical. Deposition of both initial layers is preferably carried out in a vacuum approaching 10 to the -8th power Torr.
Lewicki, G. W.↗
Universal limiter for transient interpolation modeling of the advective transport equations: The ULTIMATE conservative difference scheme
A fresh approach is taken to the embarrassingly difficult problem of adequately modeling simple pure advection. An explicit conservative control-volume formation makes use of a universal limiter for transient interpolation modeling of the advective transport equations. This ULTIMATE conservative difference scheme is applied to unsteady, one-dimensional scalar pure advection at constant velocity, using three critical test profiles: an isolated sine-squared wave, a discontinuous step, and a semi-ellipse. The goal, of course, is to devise a single robust scheme which achieves sharp monotonic resolution of the step without corrupting the other profiles. The semi-ellipse is particularly challenging because of its combination of sudden and gradual changes in gradient. The ULTIMATE strategy can be applied to explicit conservation schemes of any order of accuracy. Second-order schemes are unsatisfactory, showing steepening and clipping typical of currently popular so-called high resolution shock-capturing of TVD schemes. The ULTIMATE third-order upwind scheme is highly satisfactory for most flows of practical importance. Higher order methods give predictably better step resolution, although even-order schemes generate a (monotonic) waviness in the difficult semi-ellipse simulation. Little is to be gained above ULTIMATE fifth-order upwinding which gives results close to the ultimate for which one might hope.
Leonard, B. P.↗
Technology for the Future: In-Space Technology Experiments Program, part 1
The purpose of the Office of Aeronautics and Space Technology (OAST) In-Space Technology Experiment Program (In-STEP) 1988 Workshop was to identify and prioritize technologies that are critical for future national space programs and require validation in the space environment, and review current NASA (In-Reach) and industry/university (Out-Reach) experiments. A prioritized list of the critical technology needs was developed for the following eight disciplines: structures; environmental effects; power systems and thermal management; fluid management and propulsion systems; automation and robotics; sensors and information systems; in-space systems; and humans in space. This is part one of two parts and is the executive summary and experiment description. The executive summary portion contains keynote addresses, strategic planning information, and the critical technology needs summaries for each theme. The experiment description portion contains brief overviews of the objectives, technology needs and backgrounds, descriptions, and development schedules for current industry, university, and NASA space flight technology experiments.
Breckenridge, Roger A.↗
Technology for the Future: In-Space Technology Experiments Program, part 2
The purpose of the Office of Aeronautics and Space Technology (OAST) In-Space Technology Experiments Program In-STEP 1988 Workshop was to identify and prioritize technologies that are critical for future national space programs and require validation in the space environment, and review current NASA (In-Reach) and industry/ university (Out-Reach) experiments. A prioritized list of the critical technology needs was developed for the following eight disciplines: structures; environmental effects; power systems and thermal management; fluid management and propulsion systems; automation and robotics; sensors and information systems; in-space systems; and humans in space. This is part two of two parts and contains the critical technology presentations for the eight theme elements and a summary listing of critical space technology needs for each theme.
Breckenridge, Roger A.↗
BRN 3.1 Knockouts Affect the Vestibular, Autonomic, and Circadian Rhythm Responses to 2G Exposure
Our previous studies have demonstrated that 2G exposure via centrifugation significantly attenuated the daily mean and circadian rhythm amplitude of rat body temperature (Tb), heart rate, and activity (Act). In addition, 2G exposure activates neural responses in several vestibular, autonomic, and circadian nuclei. Although we have characterized the effect of 2G on an animal's physiological, neuronal, and behavioral responses, it will be important to understand the underlying neural and physiological mechanisms that mediate those responses. For example, the vestibular responses, proprioceptive feedback, or fluid shifts may be the critical factors that mediate the responses to 2G. As a first step to understand the relative importance of these different response pathways to altered gravitational fields, this study examined the contribution of the vestibular system by utilizing an animal model from molecular biology. Brain 3.1 (Bm 3.1) is a POU domain homeobox gene involved in the normal development of the vestibular and auditory system. Brn 3.1 deletion results in a loss of hair cells in the otoliths, semicircular canals, and cochlea. As a result mice with a Brn 3.1 deletion do not have a functioning vestibular or auditory system. The BRN 3.1 knockout mouse could be a very useful animal model for isolating the role of the vestibular system in mediating the physiological responses to 2G exposure. Therefore, this study compared the effect of 2G exposure via centrifugation between Brn 3.1 knockout (KO) versus Wildtype (W) mice.
Murakami, D. M.↗
Studies Toward Birth and Early Mammalian Development in Space
Successful reproduction is the hallmark of a species' ability to adapt to its environment and must be realized to sustain life beyond Earth. Before taking this immense step, we need to understand the effects of altered gravity on critical phases of mammalian reproduction, viz., those events surrounding pregnancy, birth and the early development of offspring. No mammal has yet undergone birth in space. however studies spanning the gravity continuum from 0 to 2-g are revealing insights into how birth and early postnatal development will proceed in space. In this presentation, I will report the results of behavioral studies of rat mothers and offspring exposed from mid- to late pregnancy to either hypogravity (0-g) or hypergravity (1.5 or 2-g).
Ronca, April E.↗
Free Re-boost Electrodynamic Tether on the International Space Station
The International Space Station (ISS) currently experiences significant orbital drag that requires constant make up propulsion or the Station will quickly reenter the Earth's Atmosphere. The reboost propulsion is presently achieved through the firing of hydrazine rockets at the cost of considerable propellant mass. The problem will inevitably grow much worse as station components continue to be assembled, particularly when the full solar panel arrays are deployed. This paper discusses many long established themes on electrodynamic propulsion in the context of Exploration relevance, shows how to couple unique ISS electrical power system characteristics and suggests a way to tremendously impact ISS's sustainability. Besides allowing launch mass and volume presently reserved for reboost propellant to be reallocated for science experiments and other critically needed supplies, there are a series of technology hardware demonstrations steps that can be accomplished on ISS, which are helpful to NASA s Exploration mission. The suggested ElectroDynamic (ED) tether and flywheel approach is distinctive in its use of free energy currently unusable, yet presently available from the existing solar array panels on ISS. The ideas presented are intended to maximize the utility of Station and radically increase orbital safety.
Bonometti, Joseph A.↗
Testing Large Structures in the Field
Field testing large structures creates unique challenges such as limited choices for boundary conditions and the fact that natural excitation sources cannot be removed. Several critical developments in field testing of large structures are reviewed, including: step relaxation testing which has been developed into a useful technique to apply large forces to operational systems by careful windowing; the capability of large structures testing with free support conditions which has been expanded by implementing modeling of the support structure; natural excitation which has been developed as a viable approach to field testing; and the hybrid approach which has been developed to allow forces to be estimated in operating structures. These developments have increased the ability to extract information from large structures and are highlighted in this presentation.
James, George↗
Failure Modes in Capacitors When Tested Under a Time-Varying Stress
Power-on failure has been the prevalent failure mechanism for solid tantalum capacitors in decoupling applications. A surge step stress test (SSST) has been previously applied to identify the critical stress level of a capacitor batch to give some predictability to the power-on failure mechanism [1]. But SSST can also be viewed as an electrically destructive test under a time-varying stress (voltage). It consists of rapidly charging the capacitor with incremental voltage increases, through a low resistance in series, until the capacitor under test is electrically shorted. When the reliability of capacitors is evaluated, a highly accelerated life test (HALT) is usually adopted since it is a time-efficient method of determining the failure mechanism; however, a destructive test under a time-varying stress such as SSST is even more time efficient. It usually takes days or weeks to complete a HALT test, but it only takes minutes for a time-varying stress test to produce failures. The advantage of incorporating a specific time-varying stress profile into a statistical model is significant in providing an alternative life test method for quickly revealing the failure mechanism in capacitors. In this paper, a time-varying stress that mimics a typical SSST has been incorporated into the Weibull model to characterize the failure mechanism in different types of capacitors. The SSST circuit and transient conditions for correctly surge testing capacitors are discussed. Finally, the SSST was applied for testing Ta capacitors, polymer aluminum capacitors (PA capacitors), and multi-layer ceramic (MLC) capacitors with both precious metal electrodes (PME) and base metal electrodes (BME). The test results are found to be directly associated with the dielectric layer breakdown in Ta and PA capacitors and are independent of the capacitor values, the way the capacitors were built, and the capacitors manufacturers. The test results also show that MLC capacitors exhibit surge breakdown voltages much higher than the rated voltage and that the breakdown field is inversely proportional to the dielectric layer thickness. The SSST data can also be used to comparatively evaluate the voltage robustness of capacitors for decoupling applications.
Liu, David (Donhang)↗