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All sourcesNASA NTRSDOE OSTI
NASA NTRS2024

Morphometric Characterization of Lunar Landing Sites

As ambitious surface exploration of the Moon commences in the 2020s, it is important to develop reliable and objective metrics for understanding the quality of future landing sites. A key prerequisite for any exploration and utilization of the lunar surface is a safe landing. One of the most important methods to provide understanding of potential metrics for landing site safety in the lunar context is the systematic comparison of candidate and historic landing sites. The goal of this project is to determine the morphometric parameters of the lunar surface at 16 successful lunar landing sites where adequate data exists to execute a quantitative comparison using various parameters. Quantitative analysis of Lunar Reconnaissance Orbiter (LRO) data should inform mission planning activities by providing morphologic metrics for landing sites including slope, Terrain Ruggedness Index (TRI), and rock abundance. These comparisons will assist mission planners and exploration scientists by providing “calibration points” for using Lunar Reconnaissance Orbiter (LRO) data to successfully plan and execute lunar powered descents in the future. The metrics included in this analysis describe the form of the terrain and can be calculated for any potential future landing site. Another objective of this project is to determine how the derived morphologic parameters for the same landing site change between common pixel scales. In ideal lighting conditions, 2m/px Narrow Angle Camera Digital Terrain Models (NAC DTMs) can be assembled using stereoscopic imagery from two or more concentric orbits of the LRO. However, due to low light conditions near the lunar poles, the highest quality data for many potential lunar landing sites comes from the Lunar Orbiter Laser Altimeter (LOLA). Therefore, we seek to assess how the derived slope and TRI values change as a function of changes in the DTM postings from 2m/px to 5m/px.

J M McCallion↗
NASA NTRS2023

Estimating the Subsolar Magnetopause Position from Soft X-Ray Images Using a Low-Pass Image Filter

The Lunar Environment heliospheric X-ray Imager (LEXI) and Solar wind Magnetosphere Ionosphere Link Explorer (SMILE) missions will image the Earth’s dayside magnetopause and cusps in soft X-rays after their respective launches in the near future, to specify global magnetic reconnection modes for varying solar wind conditions. To support the success of these scientific missions, it is critical to develop techniques that extract the magnetopause locations from the observed soft X-ray images. In this research, we introduce a new geometric equation that calculates the subsolar magnetopause position ( R s ) from a satellite position, the look direction of the instrument, and the angle at which the X-ray emission is maximized. Two assumptions are used in this method: (1) The look direction where soft X-ray emissions are maximized lies tangent to the magnetopause, and (2) the magnetopause surface near the subsolar point is almost spherical and thus R s is nearly equal to the radius of the magnetopause curvature. We create synthetic soft X-ray images by using the Open Geospace General Circulation Model (OpenGGCM) global magnetohydrodynamic model, the galactic background, the instrument point spread function, and Poisson noise. We then apply the fast Fourier transform and Gaussian low-pass filters to the synthetic images to remove noise and obtain accurate look angles for the soft X-ray peaks. From the filtered images, we calculate R 2 and its accuracy for different LEXI locations, look directions, and solar wind densities by using the OpenGGCM subsolar magnetopause location as ground truth. Our method estimates R s with an accuracy of <0.3 R E when the solar wind density exceeds >10 cm -3 . The accuracy improves for greater solar wind densities and during southward interplanetary magnetic fields. The method captures the magnetopause motion during southward interplanetary magnetic field turnings. Consequently, the technique will enable quantitative analysis of the magnetopause motion and help reveal the dayside reconnection modes for dynamic solar wind conditions. This technique will support the LEXI and SMILE missions in achieving their scientific objectives.

Hyangpyo Kim↗
NASA NTRS2023

Hydrodynamics of bubble flow through a porous medium with applications to packed bed reactors

Gas-liquid flows through packed bed reactors (PBRs) are challenging to predict due to the tortuous flow paths that fluid interfaces must traverse. Experiments at the International Space Station showed that bubble and pulse flows are predominately observed under microgravity conditions, while the trickle and spray flows observed under terrestrial conditions are not present in microgravity. To understand the physics behind the former experiments, we simulate bubble flow through a PBR for different packing-particle-diameter-based Weber numbers and under different gravity conditions. We demonstrate different pore-scale mechanisms, such as capillary entrapment, buoyancy entrapment, and inertia-induced bubble displacement. Then, we perform a quantitative analysis by introducing new dynamic scales, dependent upon the evolving gas-liquid interfacial area, to understand the dynamic trade-offs between the inertia, capillary, and buoyancy forces on a bubble passing through a PBR. This analysis leads us to define new dimensionless Weber-like numbers that delineate bubble entrapment from bubble displacement.

Pranay P Nagrani↗
NASA NTRS2026

Parametric-Based Heat Rejection Trade Study for Lunar and Martian Surface Operations

Establishing and maintaining a sustained presence on the lunar and/or Martian surfaces will require a diverse portfolio of surface elements (e.g., habitation, mobility, power generation, etc.). Many of these systems generate excess heat that must be rejected across a wide range of magnitudes, temperatures, and duty cycles and under variable environmental conditions. To identify the most promising heat rejection approaches for this diverse portfolio, a heat rejection trade study was conducted to evaluate the performance of different technology approaches across a spectrum of surface environments and heat-load requirements. The trade study consisted of three stages: (1) development of a parametric-based modeling framework, (2) creation of a database of heat rejection technologies, surface elements, and environmental conditions for the Moon and Mars, and (3) execution of a quantitative analysis of various heat rejection technologies across different operating conditions and surface elements. The modeling framework is developed in Python and Excel to prioritize small model size and hence low computational cost to enable large parametric sweeps while avoiding the reliance on proprietary software. Individual heat rejection processes are represented as simple Excel models, and a centralized Python script interfaces with the models to coordinate the parametric study. These simple sizing models were developed to take heat load requirements and environmental parameters as inputs and compute mass, power, and volume as outputs. Rather than assess each heat rejection technology separately for each surface element, a unified parametric space was developed to evaluate all technologies across all elements. This parametric space includes factors related to heat load (e.g., magnitude or temperature) and environment (e.g., surface temperature, sky temperature, solar flux). This effort generated a database containing information on over 60 heat rejection technologies and 30 surface elements. For each surface element, the expected heat rejection requirements were documented and analyzed to determine the most common needs shared across all elements. Environmental conditions at various lunar and Martian latitudes were also established for worst-case hot and worst-case cold scenarios. High-fidelity heat rejection models are currently under development. Preliminary trades between heat rejection technologies including radiators, venting technologies, convective coolers, and more have been conducted to identify promising options. This presentation will summarize the preliminary trade results and provide an overview and discussion of the expected heat loads and thermal environments for sustained surface operations on the Moon and Mars.

Heat Rejection↗
NASA NTRSDate not supplied

In Situ Synchrotron Micro-CT of Microballoon-Filled RTV Silicone During Thermal Decomposition

This work investigates the thermal decomposition of microballoon-filled room-temperature-vulcanizing (RTV) silicone using time-resolved synchrotron micro-CT at the Advanced Light Source. In situ imaging of constrained and unconstrained samples captures the evolution of the internal microstructure during heating, including material expansion, microballoon and void growth, tearing, pyrolysis, shrinkage, and increasing porosity. The measurements provide new insight into the mechanisms governing RTV degradation and generate three-dimensional data for future quantitative analysis and material-response model development.

TPS↗
DOE OSTI2014

Methods for threshold determination in multiplexed assays

Methods for determination of threshold values of signatures comprised in an assay are described. Each signature enables detection of a target. The methods determine a probability density function of negative samples and a corresponding false positive rate curve. A false positive criterion is established and a threshold for that signature is determined as a point at which the false positive rate curve intersects the false positive criterion. A method for quantitative analysis and interpretation of assay results together with a method for determination of a desired limit of detection of a signature in an assay are also described.

47 OTHER INSTRUMENTATION↗
DOE OSTI2014

Beyond Human Capital Development: Balanced Safeguards Workforce Metrics and the Next Generation Safeguards Workforce

Since its establishment in 2008, the Next Generation Safeguards Initiative (NGSI) has achieved a number of objectives under its five pillars: concepts and approaches, policy development and outreach, international nuclear safeguards engagement, technology development, and human capital development (HCD). As a result of these efforts, safeguards has become much more visible as a critical U.S. national security interest across the U.S. Department of Energy (DOE) complex. However, limited budgets have since created challenges in a number of areas. Arguably, one of the more serious challenges involves NGSI’s ability to integrate entry-level staff into safeguards projects. Laissez fair management of this issue across the complex can lead to wasteful project implementation and endanger NGSI’s long-term sustainability. The authors provide a quantitative analysis of this problem, focusing on the demographics of the current safeguards workforce and compounding pressures to operate cost-effectively, transfer knowledge to the next generation of safeguards professionals, and sustain NGSI safeguards investments.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2014

Multipole and field uniformity tailoring of a 750 MHz rf dipole

In recent years great interest has been shown in developing rf structures for beam separation, correction of geometrical degradation on luminosity, and diagnostic applications in both lepton and hadron machines. The rf dipole being a very promising one among all of them. The rf dipole has been tested and proven to have attractive properties that include high shunt impedance, low and balance surface fields, absence of lower order modes and far-spaced higher order modes that simplify their damping scheme. As well as to be a compact and versatile design in a considerable range of frequencies, its fairly simple geometry dependency is suitable both for fabrication and surface treatment. The rf dipole geometry can also be optimized for lowering multipacting risk and multipole tailoring to meet machine specific field uniformity tolerances. In the present work a survey of field uniformities, and multipole contents for a set of 750 MHz rf dipole designs is presented as both a qualitative and quantitative analysis of the inherent flexibility of the structure and its limitations.

Delayen, Jean R.↗
DOE OSTI2015

Deciphering a removed text on a 16th c. centrepiece: The benefits of using AGLAEMap and AXSIA to process PIXE maps.

In the field of archaeometry, it is not uncommon to be presented with art objects that contain inscriptions, signatures and other writings that are nearly impossible to read. Scanned microbeam PIXE offers an attractive approach to attack this problem, but even then the distribution of characteristic X-rays of the element(s) used in these writings can remain illegible. We show in this paper that two methods were used to reveal the inscription: first the use of a GUPIXWin, TRAUPIXE and AGLAEMap software suite enables to make quantitative analysis of each pixel, to visualize the results and to select X-ray peaks that could enable to distinguish letters. Then, the Automated eXpert Spectral Image Analysis (AXSIA) program developed at Sandia, which analyzes the x-ray intensity vs. Energy and (X, Y) position “datacubes”, was used to factor the datacube into 1) principle component spectral shapes and 2) the weighting images of these components. The specimen selected for this study was a silver plaque representing a scroll from the so-called “MerkelscheTafelaufsatz,” a centrepiece made by the Nuremberg goldsmith Wenzel Jamnitzer in 1549. X-ray radiography of the plaque shows lines of different silver thicknesses, meaning that a text has been removed. The PIXE analysis used a 3-MeV proton beam focused to 50μm and scanned across the sample on different areas of interest of several cm². This analysis showed major elements of Cu and Ag, and minor elements such as Pb, Au, Hg. X-ray intensity maps were then made by setting windows on the various x-ray peaks but the writing on the centrepiece was not revealed even if the map of Cu after data treatment at AGLAE enabled to distinguish some letters. The AXSIA program enabled to factor two main spectral shapes from the datacube that were quite similar and involved virtually all of the X-rays being generated. Nevertheless, small differences between these factors were observed for the Cu K X-rays, Pb, Bi and Au L X-rays. The plot of the factor with the highest Au signal gave also information on the shape of some letters. The comparison of the results obtained by the two methods shows that they both drastically improve the resolution and contrast of such writings and that each of the method can also bring different information on the composition and thus the techniques used for the writing.

AGLAEMap↗
DOE OSTI2019

Quantifying Spatially Varying Blur in X-ray Radiographic Imaging Systems

Two goals of quantitative analysis of radiographic data from dynamic material experiments are to identify edge locations and infer material density. Understanding the systematic effect of blur of the imaging system through calibration imagery is the fist step to quantifying, modeling, and eventually mitigating its effect. If modeling geometry and assumptions can be expressed through operator transformations, this leads to natural modifications of the likelihood and prior in a Bayesian formulation of the inverse problem.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2019

ADVANCED-STEM-BASED DEEP LEARNING FOR SEMANTIC SEGMENTATION OF DEFECTS IN STEELS

In this work, we developed a novel deep convolutional neural network (DCNN) model, called DefectNet, for robust and automated semantic segmentation of three crystallographic defects including line dislocations, precipitates and voids commonly observed in structural metals and alloys. In previous work, we established an experimental protocol for a diffraction contrast imaging scanning transmission electron microscopy (DCI STEM) technique and tailored it specifically for imaging defects in popular iron-based structural alloy. Thus, the DefectNet was trained over a small but high-quality DCI STEM defect image sets of a HT-9 martensitic steel before and after neutron irradiation for 111.8 dpa at 412°C. For the defect quantification that typically takes at least half an hour even for an expert, with a good model the machine learning algorithm can produce more reproducible and reliable quantification in a few seconds. This work demonstrates the feasibility of using deep learning algorithms for fast and accurate defect quantitative analysis.

Machine Learning, Radiation effects, Image analysi↗
DOE OSTI2017

Nanoscale Compositional Mapping of Spent HZSM-5: An Atom Probe Tomography Study

Zeolites are highly crystalline and porous materials possessing a well-defined one- to three-dimensional pore structure. Zeolites play a major role in the petrochemical industry, exploitation of non-conventional petroleum resources and nonpetroleum resources like gas and coal. Recently, zeolite has been researched heavily in the valorization of biomass for renewable fuel and chemical generation. It has been reported widely that zeolite deactivation can occur via two main mechanisms. The first one is leaching of alumina from the unit structure of the zeolite in the presence of steam; this mechanism causes the irreversible deactivation. The second mechanism is the formation of coke during the transformation of organic compounds in the pores and/or the outer surface and the poisoning of the active sites and/or blocking of the pores. The catalyst deactivation from this mode can be regenerated by burning the catalyst under oxidative conditions. Repeated thermal treatment for spent catalyst regeneration is also shown to cause permanent modification of the zeolite structure. So identifying the nature and the location of the coking material and changes in Al distribution in catalyst after catalytic reactions becomes imperative. Recently, a relatively new technique called atom probe tomography (APT) has been increasingly used to perform 3D quantitative analysis of element distribution with sub-nanometer scale spatial resolution and high mass sensitivity up to the few ppm level of concentration of elements in materials. In the study we used a multimodal approach including C K-edge x-ray absorption along with 13C cross polarization magic angle spinning nuclear magnetic resonance (CP-MAS NMR) and APT to investigate element distribution within a HZSM-5 as-synthesized condition and after ethanol conversion reaction.

Devaraj, Arun↗
DOE OSTI2021

MeV Scale Physics in MicroBooNE

This thesis presents the reconstruction and measurement of low-energy electromagnetic activity with beam neutrino interactions within the MicroBooNE Liquid Argon Time Projection Chamber (LArTPC). LArTPCs have proven to be excellent detectors to measure neutrino interaction cross sections and are being used to perform precision measurements of neutrino oscillation parameters. The work presented in this thesis has demonstrated unprecedentedly low, sub-MeV energy thresholds that have increased sensitivity of LArTPCs to detect neutrino interactions from core collapse supernovae and Muon Decay at Rest (µDAR). In addition, such low thresholds have also increased measurement sensitivity for interactions from Beyond the Standard Model (BSM) candidates such as millicharged particles and nuclear and electron recoils from dark matter candidate particles. On the reconstruction side, this work has established an energy resolution of 6.3% for electromagnetic activity i the 0-5 MeV energy range within the MicroBooNE LArTPC. Additionally this work presents the quantitative analysis of the low-energy activity emanating from G-10 support ribs in MicroBooNE and discusses how such activity could be a problematic source of background for low-energy physics analyses in future neutrino detectors such as the Deep Underground Neutrino Experiment (DUNE).

Bhat, Avinay↗
DOE OSTI2023

Environmental and Economic Implications of Emerging Plastic Recycling Technologies

Recycling will play a crucial role in mitigating plastic pollution and promoting a circular economy for polymers. Quantitative analysis can help guide the optimization and implementation of these plastic management strategies, enabling increased circularity while minimizing costs, energy use, greenhouse gas emissions, and other environmental impacts. This talk will outline the Bio-Optimized Technologies to keep Thermoplastics out of Landfills and the Environment (BOTTLE) Consortium's approach to analysis-guided plastic recycling research. Stringent process modelling, life cycle assessment, and techno-economic analysis are used to benchmark the technical feasibility, environmental impacts, and costs of chemical and biological recycling technologies in comparison to conventional fossil fuel-based plastic manufacturing. Across emerging recycling strategies, several key challenges become apparent - including plastic feedstock pretreatment requirements, high energy or chemical use, and recycled plastic yields and quality - highlighting opportunities for future innovation. Through this consistent and in-depth analysis approach, BOTTLE aims to provide the plastics community with key metrics and insights to drive plastic recycling innovation towards a more sustainable and circular economy.

circular economy↗
DOE OSTI2015

Increasing of MERARG experimental performances: on-line fission gas release measurement by mass spectrometry

The MERARG device - implemented at the LECASTAR Hot Laboratory, at the CEA Cadarache - allows characterizing nuclear fuels with respect to the behaviour of fission gases during thermal transients representative of normal or off normal operating nuclear power plant conditions. The fuel is heated in order to extract a part or the total gas inventory it contains. Fission Gas Release (FGR) is actually recorded by mean of both on-line gamma spectrometry station and micro gas chromatography. These two devices monitor the quantity and kinetics of fission gas release rate. They only address {sup 85}Kr radioactive isotope and the elemental quantification of Kr, Xe and He (with a relatively low detection limit in the latter case, typically 5-10 ppm). In order to better estimate the basic mechanisms that promote fission gas release from irradiated nuclear fuels, the CEA fuel study department decided to improve its experimental facility by modifying MERARG to extend the studies of gamma emitter fission gases to all gases (including Helium) with a complete isotopic distribution capability. To match these specifications, a Residual Gas Analyser (RGA) has been chosen as mass spectrometer. This paper presents a review of the main aspects of the qualification/calibration phase of the RGA type analyser. In particular, results recorded over three mass ranges 1-10 u, 80-90 u and 120-140 u in the two classical modes of MERARG, i.e. on-line and off-line measurements are discussed. Results obtained from a standard gas bottle show that the quantitative analysis at a few ppm levels can be achieved for all isotopes of Kr and Xe, as well as masses 2 and 4 u. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2015

A new measurement method of tritiated water with no radioactive waste- for monitoring post - 15050

A new measurement method has been developed by using a conventional liquid scintillation counter (LSC) with plastic scintillator pellets (PS-pellets) which is used as an alternative material of liquid scintillator. The measurement efficiency (%=cpm/dpm x 100) of PS-pellets with a conventional LSC is as high as using a liquid scintillator. Measurement efficiency of tritiated water was more than 50% by using PS-pellets for LSC without liquid scintillator. Qualitative and quantitative analysis were possible by using PS-pellets for LSC, because the PS-pellets method showed good linearity between the activity and count rate. Also, an end point of a spectrum showed a maximum energy of a radionuclide when one channel estimated 0.5 keV. The PS-pellets were reusable by dipping them in 5% soapsuds of hot water for more than overnight except for a case of measuring for a long elapsed time. So, no radioactive waste of liquid scintillator and PS-pellets is produced with this method.We designed a new field monitor and a monitoring post. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Determining Coal Ash Impacts on Radium and Thorium Background Levels in Soil Using Rare Earth Element Analyses - 18604

One challenge at large remediation sites contaminated with radiological materials is differentiating between low-level site-related contamination and NORM. This is because sites contaminated with radiological materials, such as thorium processing and mining and milling facilities, often generate wastes that contain contaminants that are similar to NORM deposits. For sites in urban areas, this issue is further compounded due to the presence of historic industrial fill (historic fill) containing materials such as fly ash, coal ash, and red brick, that exhibit elevated radioactivity levels. These materials often have activity levels near, or even well above, a site's cleanup goal. At a large Superfund Site in the eastern US (Site), many of the suspected Site-related fill areas are commingled with coal and fly ash. As the cleanup criteria for the radionuclides of concern (ROC), radium (Ra) and thorium (Th), is 5 pico-Curies per gram above background, a four-pronged approach was developed to determine if the coal and fly ash are impacting the background levels of the ROCs. This evaluation included a review of boring logs to visually confirm the presence of historic fill, as well as coal fragments and coal ash; a literature review to establish the typical concentrations of Ra and Th found in coal and fly ash from US sources; the use of rare earth analyses to establish chemical signatures for non-Site related historic fill containing coal ash versus Site-related fill; and a quantitative analysis of Site-related data to determine if the radioactivity levels in historic fill containing coal were elevated. Soil samples were collected from two locations at the Site; fill areas containing coal ash that were not suspected to be impacted by Site activities, as well as fill areas containing coal ash that were associated with the former processing facility. These samples were analyzed for rare earth elements (REE), as well as Ra-228 and Th-232 and the ratios of lanthanum, cerium, and neodymium to Ra-228 and Th-232 were established for each sample. Based on a comparison of these data, a strong correlation was established between the rare earth/thorium decay chain ratios and the classification of material as either Site or non-Site related. These data were used to develop a higher background activity for fill areas containing non-Site related NORM. While the cleanup level defined in the Record of Decision remained unchanged, the higher background derived from the fly ash/coal ash material, as identified by REE analyses, resulted in higher project screening levels, which ensured that excavation activities did not 'chase' material that was not Site-related. To date, use of the coal ash background level has saved millions of dollars in cleanup costs since non-Site related contamination is not being remediated. Use of this approach to determine the appropriate background level for a site is relatively straightforward since it relies on visual observation of the soil for coal and fly ash, along with REE analyses, which is an inexpensive, quick, and established analytical method for soil samples. As long as a good rare earth profile of both contaminated and natural (in this case fly ash and coal ash) material can be established, the results can be quite definitive, which could result in significant volume reduction by minimizing the amount of material excavated and disposed of. This will lead to cost and time savings for what could be an otherwise costly and potentially complex excavation. Anyone performing environmental remediation of NORM contaminated sites may benefit from this paper and presentation. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗