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DOE OSTI2021

THERMAL/STRUCTURAL ANALYSIS OF THE AXION QUANTUM METROLOGY CAVITY AND ITS COMPONENTS

This research was centered around maximizing the capability to cool dielectric material within a containment unit, or Photonic Band Gap (PBG) cavity, designed for detecting axion dark matter and identifying the unit’s thermal properties. There are multiple types of PBG cavities, but the latest version that axion researchers wish to use has been theorized to contain possible issues related to its thermal properties. Thermal conductivity is an issue with the dielectric material because it is made from alumina which is highly insulative. This is important since the research is being done in a cryogenic environment and the thermal noise affects the quantum bit used for detecting the axion to photon conversion process. Therefore, any improvements to this unit should be justified and implemented but are not entirely limited to thermal contact related aspects of PBG cavities. A prospect of using sapphire in place of alumina also exists, but this is a more expensive, less tested, and more elusive material to justify the creation of a full dielectric structure out of sapphire. Thermal aspects of the cavity were analyzed using finite element method (FEM) and an experiment designed to test different thermal joint materials. FEM was used to check the contraction of the cavity during cooling, the contact quality between the dielectric material and cavity wall, theheat flow rate through the assembly, and helps visualize the cavity’s reaction to different design changes. A simple comparison between thermal conductivity curves justified the usage of sapphire over alumina from a thermal property point of view. Thus, the method of experimentation had an additional dielectric material, sapphire, to test with and compare to alumina. The thermal test identified which material is best to use for a thermal joint but also simultaneously found the conductance of the joint and dielectric material as well as an estimate for what the temperature is inside the larger scale cavity since a thermometer cannot be placed inside the PBG when it cools. Initially, the cavity simulation was tested for structural deformation properties and stress distribution since it is made of copper which contracts heavily in comparison to most other materials. The reduction in volume of the cavity was less than anticipated which gave more room for a possible usage of a modified thermal joint for additional contact area and higher conductivity.

43 PARTICLE ACCELERATORS↗

DOE OSTI2021

Localization of Nonblinking Point Sources Using Higher-Order-Mode Detection and Optical Heterodyning: Developing a Strategy for Extending the Scope of Molecular, Super-resolution Imaging

While the stochastic, “blinking” nature of fluorescent systems has enabled the super-resolution of their localization by the fitting of their point-spread functions (PSFs), this strategy cannot be exploited for similar resolution of “nonblinking” systems, such as those that might be encountered in a coherent Raman experiment. An alternative method for subdiffraction-limited imaging lies in the exploitation of optical heterodyning. For example, if a Gaussian PSF (a TEM00 mode) of a point emitter is displaced with respect to the origin of the optical system, photons in the higher-order TEM modes carry information about that displacement. Information concerning the displacement can be extracted from photons in these higher-order modes. These photons can be collected by optical heterodyning, which exploits the large gain in a detector’s response to an optical signal from an emitter coupled to a local oscillator, which is prepared in the TEM of interest, e.g., TEM10. We have generalized and developed the heterodyning technique to localize point emitters via the detection of higher-order spatial modes. We have developed a theoretical approach to find a practical estimation limit of the localization parameters using a realistic model that accounts for shot noise, background noise, and Gaussian noise. To demonstrate the applicability of the method, we designed experiments in which a laser is a surrogate for one and two point emitters. Using the Fisher information and its accompanying Cramér-Rao lower bound, we demonstrate super-resolution localization in these cases: we show that objects can be localized to roughly 2–3 orders of magnitude of their point-spread function’s size for a given optical system. Finally and most importantly, it is suggested that the results will ultimately be generalizable to multiple emitters and, most importantly, to “nonblinking” molecular systems, which will be essential for broadening the scope of super-resolution measurements beyond the limits of fluorescence-based techniques.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

NASA NTRS2018

A GNSS Receiver for Small-Sats Enabling Precision POD, Radio Occultations and Reflections

A low cost, low power, and low mass GNSS receiver (called Cion) has been developed and is currently flying on the CICERO cubesats. The receiver was designed in less than a year by JPL for Tyvak and GeoOptics for use in the GeoOptics CICERO constellation and leverages 25 years of JPL GNSS reciever design experience. Cion uses a commercial off-the-shelf (COTS) computer along with existing space qualified RF down-converters, software, and firmware to produce atmospheric Radio Occultation (RO) data. By combining a FPGA with dual core ARM processor and an embedded system controller, the Xilinx Zynq processor is an enabling technology that provides a customizable digital signal processing platform integrated into the computer (System on a chip) and enables off-the-shelf hardware to become the main engine behind this software defined radio. Using Linux for the on-board computer allows for fast development times and liberal use of existing open source software libraries. The parts of the receiver that require realtime implementation are performed in the Field Programmable Gate Array (FPGA), which can also be reprogrammed in flight. While the Zynq is not rad hard, the silicon on insulator (SOI) technology is rad tolerant ‘by accident’, allowing for its use in many space-based applications. Early results show that the Cion is working as designed, has demonstrated the first known GLONASS occultations, and obtains high quality atmospheric profiles with excellent lower troposphere penetration (near Earth’s surface).

Young, Larry↗

NASA NTRS2015

Characterization of Encapsulated Corrosion Inhibitors Containing Microparticles for Environmentally Friendly Smart Coatings

This poster presents the results obtained from experiments designed to evaluate the release properties, as well as the corrosion inhibition effectiveness, of several encapsulated corrosion inhibitors. Microencapsulation has been used in the development of environmentally friendly multifunctional smart coatings. This technique enables the incorporation of autonomous corrosion detection, inhibition and self-healing functionalities into many commercially available coating systems. Select environmentally friendly corrosion inhibitors were encapsulated in organic and inorganic pH-sensitive microparticles and their release in basic solutions was studied. The release rate results showed that the encapsulation can be tailored from fast, for immediate corrosion protection, to slow, which will provide continued long-term corrosion protection. The incorporation of several corrosion inhibitor release profiles into a coating provides effective corrosion protection properties. To investigate the corrosion inhibition efficiency of the encapsulated inhibitors, electrochemical techniques were used to obtain corrosion potential, polarization curve and polarization resistance data. These measurements were performed using the free as well as the encapsulated inhibitors singly or in combinations. Results from these electrochemical tests will be compared to those obtained from weight loss and other accelerated corrosion experiments.

Coatings↗

NASA NTRS2011

Calibrated Noise Measurements with Induced Receiver Gain Fluctuations

The lack of well-developed techniques for modeling changing statistical moments in our observations has stymied the application of stochastic process theory in science and engineering. These limitations were encountered when modeling the performance of radiometer calibration architectures and algorithms in the presence of non stationary receiver fluctuations. Analyses of measured signals have traditionally been limited to a single measurement series. Whereas in a radiometer that samples a set of noise references, the data collection can be treated as an ensemble set of measurements of the receiver state. Noise Assisted Data Analysis is a growing field of study with significant potential for aiding the understanding and modeling of non stationary processes. Typically, NADA entails adding noise to a signal to produce an ensemble set on which statistical analysis is performed. Alternatively as in radiometric measurements, mixing a signal with calibrated noise provides, through the calibration process, the means to detect deviations from the stationary assumption and thereby a measurement tool to characterize the signal's non stationary properties. Data sets comprised of calibrated noise measurements have been limited to those collected with naturally occurring fluctuations in the radiometer receiver. To examine the application of NADA using calibrated noise, a Receiver Gain Modulation Circuit (RGMC) was designed and built to modulate the gain of a radiometer receiver using an external signal. In 2010, an RGMC was installed and operated at the National Institute of Standards and Techniques (NIST) using their Noise Figure Radiometer (NFRad) and national standard noise references. The data collected is the first known set of calibrated noise measurements from a receiver with an externally modulated gain. As an initial step, sinusoidal and step-function signals were used to modulate the receiver gain, to evaluate the circuit characteristics and to study the performance of a variety of calibration algorithms. The receiver noise temperature and time-bandwidth product of the NFRad are calculated from the data. Statistical analysis using temporal-dependent calibration algorithms reveals that the natural occurring fluctuations in the receiver are stationary over long intervals (100s of seconds); however the receiver exhibits local non stationarity over the interval over which one set of reference measurements are collected. A variety of calibration algorithms have been applied to the data to assess algorithms' performance with the gain fluctuation signals. This presentation will describe the RGMC, experiment design and a comparative analysis of calibration algorithms.

Racette, Paul↗

NASA NTRS2014

Laboratory Investigations of the Complex Refractory Organic Material Produced from Irradiation of Pluto Ice Analogs

Much of Pluto's surface consists of N2 ice with smaller amounts of CH4 and CO ices. Despite the low temperature (approximately 45K), chemistry can be driven in the surface ices by radiation processing such as cosmic ray bombardment. When cosmic rays strike the surface, much of their energy is dispersed in the form of secondary electrons, which in turn drive much of the resulting chemical reactions. Laboratory experiments designed to simulate the conditions on these icy bodies may provide insight into this chemistry. Significant progress has been made in the laboratory toward understanding the smaller, simple compounds produced in the solid phase by radiation processing of (N2, CH4, CO) ices (Bohn et al. 1994; Moore & Hudson 2003; Hodyss et al. 2011; Kim and Kaiser 2012). Recently Materese et al. (2014) used a variety of techniques to better characterize the refractory materials produced from the UV photo-irradiation of N2:CH4:CO ices. However, because Pluto's atmosphere is optically thick to Lyman-alpha UV radiation it is important to re-examine the results using an alternate radiation source. Our latest work has consisted of the analysis of refractory materials produced from the electron bombardment of low temperature N2(‐), CH4(‐), and CO(‐)containing ices (100:1:1). The ice mixture was chosen to be analogous to the known surface ices on Pluto and the radiation source was chosen to mimic the secondary electrons produced by cosmic rays bombardment. The residues were studied using multiple chemical techniques including, infrared (IR) spectroscopy, X‐ray absorption near‐edge structure (XANES) spectroscopy, and gas chromatography coupled with mass spectrometry (GC‐MS). The organic residues produced in these experiments can be seen as an analog for the refractory component of the surface of Pluto, and are compared with the residues previously obtained from UV photo‐irradiation. UV and near‐ IR spectroscopy of the surfaces of Pluto and Charon during the encounter with NASA's New Horizons spacecraft in 2015, will give the first close‐up measurements of ices and their photoproducts. Laboratory measurements and experiments will provide a better context for the data returned by the spacecraft.

organics↗

NASA NTRS1993

Gas-grain simulation experiment module conceptual design and gas-grain simulation facility breadboard development

This report delineates the Option portion of the Phase A Gas-Grain Simulation Facility study. The conceptual design of a Gas-Grain Simulation Experiment Module (GGSEM) for Space Shuttle Middeck is discussed. In addition, a laboratory breadboard was developed during this study to develop a key function for the GGSEM and the GGSF, specifically, a solid particle cloud generating device. The breadboard design and test results are discussed and recommendations for further studies are included. The GGSEM is intended to fly on board a low earth orbit (LEO), manned platform. It will be used to perform a subset of the experiments planned for the GGSF for Space Station Freedom, as it can partially accommodate a number of the science experiments. The outcome of the experiments performed will provide an increased understanding of the operational requirements for the GGSF. The GGSEM will also act as a platform to accomplish technology development and proof-of-principle experiments for GGSF hardware, and to verify concepts and designs of hardware for GGSF. The GGSEM will allow assembled subsystems to be tested to verify facility level operation. The technology development that can be accommodated by the GGSEM includes: GGSF sample generation techniques, GGSF on-line diagnostics techniques, sample collection techniques, performance of various types of sensors for environmental monitoring, and some off-line diagnostics. Advantages and disadvantages of several LEO platforms available for GGSEM applications are identified and discussed. Several of the anticipated GGSF experiments require the deagglomeration and dispensing of dry solid particles into an experiment chamber. During the GGSF Phase A study, various techniques and devices available for the solid particle aerosol generator were reviewed. As a result of this review, solid particle deagglomeration and dispensing were identified as key undeveloped technologies in the GGSF design. A laboratory breadboard version of a solid particle generation system was developed and characterization tests performed. The breadboard hardware emulates the functions of the GGSF solid particle cloud generator in a ground laboratory environment, but with some modifications, can be used on other platforms.

Zamel, James M.↗

NASA NTRS1993

Determination of parameters for hypervelocity dust grains encountered in near-Earth space

Primarily interest was in the determination of the population of micrometeoroids and space debris and interpretation of the hole size in a thin film or in a micropore foam returned from space with theoretical calculations describing the event. In order to augment the significance of the theoretical calculations of the impact event, an experiment designed to analyze the charge production due to hypervelocity impacts on thin films also produced data which described the penetration properties of micron and sub-micron sized projectiles. The thin film penetration sites in the 500 A and 1000 A aluminum films were counted and a size distribution function was derived. In the case of the very smallest dust grains, there were no independent measurements of velocities like that which existed for the larger dust grains (d(sub p) is less than or equal to 1 micron). The primary task then became to assess the relationship between the penetration hole and the particle diameter of the projectile which made the hole. The most promising means to assess the measure of the diameters of impacting grains came in the form of comparing cratering mechanics to penetration mechanics. Future experimentation will produce measurements of the cratering as opposed to the penetrating event. Particles encountered by surfaces while being flown in space will degrade that surface in a systematic manner even when the impact is with small hypervelocity particles, d(sub p) is less than or equal to 10 microns. Though not to a degree which would precipitate a catastrophic failure of a system, the degradation of the materials comprising the interconnected system will occur. It is the degradation of the optical system and the subsequent embrittlement of other materials that can lead to degradation if not to failure. It is to this end that research was conducted to compare the primary consequences for experiments which will be flown to those which have been returned.

Tanner, William G.↗

NASA NTRS1989

Design and calibration of the mixing layer and wind tunnel

A detailed account of the design, assembly and calibration of a wind tunnel specifically designed for free-shear layer research is contained. The construction of this new facility was motivated by a strong interest in the study of plane mixing layers with varying initial and operating conditions. The Mixing Layer Wind tunnel is located in the Fluid Mechanics Laboratory at NASA Ames Research Center. The tunnel consists of two separate legs which are driven independently by centrifugal blowers connected to variable speed motors. The blower/motor combinations are sized such that one is smaller than the other, giving maximum flow speeds of about 20 and 40 m/s, respectively. The blower speeds can either be set manually or via the Microvax II computer. The two streams are allowed to merge in the test section at the sharp trailing edge of a slowly tapering splitter plate. The test section is 36 cm in the cross-stream direction, 91 cm in the spanwise direction and 366 cm in length. One test section side-wall is slotted for probe access and adjustable so that the streamwise pressure gradient may be controlled. The wind tunnel is also equipped with a computer controlled, three-dimensional traversing system which is used to investigate the flow fields with pressure and hot-wire instrumentation. The wind tunnel calibration results show that the mean flow in the test section is uniform to within plus or minus 0.25 pct and the flow angularity is less than 0.25 deg. The total streamwise free-stream turbulence intensity level is approximately 0.15 pct. Currently the wind tunnel is being used in experiments designed to study the three-dimensional structure of plane mixing layers and wakes.

Bell, James H.↗

NASA NTRS2016

Winds Measured by the Rover Environmental Monitoring Station (REMS) During the Mars Science Laboratory (MSL) Rover's Bagnold Dunes Campaign and Comparison with Numerical Modeling Using MarsWRF

A high density of REMS wind measurements were collected in three science investigations during MSL's Bagnold Dunes Campaign, which took place over approx. 80 sols around southern winter solstice (Ls approx. 90deg) and constituted the first in situ analysis of the environmental conditions, morphology, structure, and composition of an active dune field on Mars. The Wind Characterization Investigation was designed to fully characterize the near-surface wind field just outside the dunes and confirmed the primarily upslope/downslope flow expected from theory and modeling of the circulation on the slopes of Aeolis Mons in this season. The basic pattern of winds is 'upslope' (from the northwest, heading up Aeolis Mons) during the daytime (approx. 09:00-17:00 or 18:00) and 'downslope' (from the southeast, heading down Aeolis Mons) at night (approx. 20:00 to some time before 08:00). Between these times the wind rotates largely clockwise, giving generally westerly winds mid-morning and easterly winds in the early evening. The timings of these direction changes are relatively consistent from sol to sol; however, the wind direction and speed at any given time shows considerable intersol variability. This pattern and timing is similar to predictions from the MarsWRF numerical model, run at a resolution of approx. 490 m in this region, although the model predicts the upslope winds to have a stronger component from the E than the W, misses a wind speed peak at approx. 09:00, and under-predicts the strength of daytime wind speeds by approx. 2-4 m/s. The Namib Dune Lee Investigation reveals 'blocking' of northerly winds by the dune, leaving primarily a westerly component to the daytime winds, and also shows a broadening of the 1 Hz wind speed distribution likely associated with lee turbulence. The Namib Dune Side Investigation measured primarily daytime winds at the side of the same dune, in support of aeolian change detection experiments designed to put limits on the saltation threshold, and also appears to show the influence of the dune body on the local flow, though less clearly than in the lee. Using a vertical grid with lower resolution near the surface reduces the relative strength of nighttime winds predicted by MarsWRF and produces a peak in wind speed at approx. 09:00, improving the match to the observed diurnal variation of wind speed, albeit with an offset in magnitude. The annual wind field predicted using this grid also provides a far better match to observations of aeolian dune morphology and motion in the Bagnold Dunes. However, the lower overall wind speeds than observed and disagreement with the observed wind direction at approx. 09:00 suggest that the problem has not been solved and that alternative boundary layer mixing schemes should be explored which may result in more mixing of momentum down to the near-surface from higher layers. These results demonstrate a strong need for in situ wind data to constrain the setup and assumptions used in numerical models, so that they may be used with more confidence to predict the circulation at other times and locations on Mars.

Newman, Claire E.↗

DOE OSTI2023

Athena-I CUBIT Journal Files

The Monte Carlo N-Particle (MCNP)1 transport code version 6 (also known as MCNP6) has the capability for tracking particles on unstructured mesh (UM) geometry models embedded into con structive solid geometry (CSG) cells. This feature has been developed for performing calculations of complex geometry models because manually creating CSG models is a time-consuming and error prone process as the complexities of geometries increase. The UM capability was originally designed to work with UM models created with the Abaqus software and ASCII input files that it generates. The MCNP code version 6.0 and later can process UM models formatted as Abaqus input files. Starting with version 6.3, MCNP can also process HDF5 mesh input files. External codes must be used to generate Abaqus input files for MCNP UM calculations. CUBIT, the Sandia National Laboratory automated mesh generation toolkit, can generate a UM model formatted as an Abaqus input file. However, the Abaqus input files exported from CUBIT cannot be used for MCNP simulations because it lacks the proper syntax. A Python script was developed to convert an Abaqus file created by CUBIT to an Abaqus file format that MCNP can process. Creating UM models for complex geometries is not an easy task. The process of creating UM models in CUBIT for MCNP simulations is detailed in. CUBIT provides several user interface options including a graphical user interface (GUI) and a command line interface. A GUI provides an easy way to use CUBIT without learning the CUBIT command syntax. When using CUBIT with either interface option, command lines are written into an ASCII file known as a journal file; this journal file can be edited and archived so that it can be played back in CUBIT to automatically generate a UM model. This report describes the CUBIT journal files of the UM models developed for Athena-I. The Athena platform, an energy-tuning assembly, was developed to spectrally shape the National Ignition Facility (NIF) deuterium-tritium fusion neutron source to a thermonuclear (fusion) plus prompt fission neutron spectrum with capability to act as a short-pulse neutron source. MCNP6 was used for the Athena experiment design analysis.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

NASA NTRSDate not supplied

m:N ConOps/R&R Remote Simulation

This presentation details the experimental design of an investigation of small unmanned aircraft system (sUAS) operations involving multiple vehicle management by a remote operator. The study is part of an ongoing effort to explore multiple vehicle control by multiple operators, i.e., the control of N vehicles by m operators (m:N operations). For this effort, NASA and collaborators have developed prototypes of a concept of operations (ConOps), roles and responsibilities (R&R) for operators and supervisors, and a ground control station (GCS), including software displays and interfaces. Participants in this study acted as the pilot-in-command of twelve aircraft flying pre-approved routes in a simulation of a food delivery operation utilizing sUAS in the San Diego, CA area. Each participant experienced four experimental trials. Twice within the course of each trial, participants were responsible for responding to a sudden, unanticipated, and high-priority contingency: an airspace restriction for sUAS operations known as a UAS Volume Reservation (UVR). Upon issuance of a UVR, pilots were expected to reroute affected vehicles around the airspace. The level of automation (LoA) and workload of the flight rerouting task were varied. The LoA was manipulated by providing reroute suggestions ("auto" condition) for aircraft or by requiring pilots to manually reroute ("manual" condition) affected vehicles. Workload was varied as a function of the number of vehicles affected by the UVR contingencies: 2 vehicles ("low workload" condition) versus 4 vehicles ("high workload" condition). Additionally, some vehicles required pilots to adjust for terrain conflicts while avoiding the UVR region. Due to the COVID-19 pandemic, in-person data collection for this study was not possible. Researchers adapted to this circumstance through the development of remote data collection protocol. Participants were able to view adapted GCS displays using the Microsoft Teams teleconferencing platform and responded to events by using a verbal protocol developed for the experiment. Using this protocol, participants provided instructions for actions to a researcher, referred to as the surrogate, to carry out on their behalf. This presentation describes the experiment design, including special details for remote data collection via a subject-surrogate configuration, and concludes with planned data analysis and results to be presented at a later date.

multi-UAS↗

DOE OSTI2023

Photon-rejection power of the Light Dark Matter eXperiment in an 8 GeV beam

The Light Dark Matter eXperiment (LDMX) is an electron-beam fixed-target experiment designed to achieve comprehensive model independent sensitivity to dark matter particles in the sub-GeV mass region. An upgrade to the LCLS-II accelerator will increase the beam energy available to LDMX from 4 to 8 GeV. Using detailed GEANT4-based simulations, we investigate the effect of the increased beam energy on the capabilities to separate signal and background, and demonstrate that the veto methodology developed for 4 GeV successfully rejects photon-induced backgrounds for at least 2 × 10 14 electrons on target at 8 GeV.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

NASA NTRS1996

Design of Plant Gas Exchange Experiments in a Variable Pressure Growth Chamber

Sustainable human presence in extreme environments such as lunar and martian bases will require bioregenerative components to human life support systems where plants are used for generation of oxygen, food, and water. Reduced atmospheric pressures will be used to minimize mass and engineering requirements. Few studies have assessed the metabolic and developmental responses of plants to reduced pressure and varied oxygen atmospheres. The first tests of hypobaric pressures on plant gas exchange and biomass production at the Johnson Space Center will be initiated in January 1996 in the Variable Pressure Growth Chamber (VPGC), a large, closed plant growth chamber rated for 10.2 psi. Experiments were designed and protocols detailed for two complete growouts each of lettuce and wheat to generate a general database for human life support requirements and to answer questions about plant growth processes in reduced pressure and varied oxygen environments. The central objective of crop growth studies in the VPGC is to determine the influence of reduced pressure and reduced oxygen on the rates of photosynthesis, dark respiration, evapotranspiration and biomass production of lettuce and wheat. Due to the constraint of one experimental unit, internal controls, called pressure transients, will be used to evaluate rates of CO2 uptake, O2 evolution, and H2O generation. Pressure transients will give interpretive power to the results of repeated growouts at both reduced and ambient pressures. Other experiments involve the generation of response functions to partial pressures of O2 and CO2 and to light intensity. Protocol for determining and calculating rates of gas exchange have been detailed. In order to build these databases and implement the necessary treatment combinations in short time periods, specific requirements for gas injections and removals have been defined. A set of system capability checks will include determination of leakage rates conducted prior to the actual crop growouts. Schedules of experimental events for lettuce and wheat are outlined and include replications in time of diurnal routines, pressure transients, variable pO2, pO2/pCO2 ratio, and light intensity responses.

Corey, Kenneth A.↗

DOE OSTI2024

Autonomous Output‐Oriented Aerosol Jet Printing Enabled by Hybrid Machine Learning

Additive manufacturing (AM) is rapidly revolutionizing modern manufacturing with recent progress in advanced printing methods and improved properties of printed materials. However, traditional AM methods are limited by their input‐oriented nature, which demands tedious trial‐and‐error tuning of printing parameters to achieve desired output properties. Here, in this work, an output‐oriented artificial intelligence‐integrated AM (AIAM) method is reported that enables an user to specify desired output properties while the printer autonomously discovers the optimal input printing parameters by integrating hybrid machine learning models and in situ measurements. Based on a predictive mapping between the input printing parameters and the output properties of interests established with <20 experiments designed by active learning, inverse design tasks are performed to intelligently generate the printing parameter settings that lead to desired outcomes using reinforcement learning. This method is demonstrated by autonomous aerosol jet printing (AJP) of conductive polymer films and achieving user‐defined electrical resistances with an ultralow error of 3.7%. The AIAM method, with its output‐oriented nature, holds the potential to significantly improve the autonomy, predictability, efficiency, and accessibility of the AM processes, which will unlock new possibilities in the autonomous and intelligent printing of a broad range of functional materials and devices.

36 MATERIALS SCIENCE↗

DOE OSTI2022

Interactions Between Diabetes Mellitus and Osteoarthritis: From Animal Studies to Clinical Data

Diabetes mellitus (DM) and osteoarthritis (OA) are commonly known metabolic diseases that affect a large segment of the world population. These two conditions share several risk factors such as obesity and aging; however, there is still no consensus regarding the direct role of DM on OA development and progression. Interestingly, both animal and human studies have yielded conflicting results, with some showing a significant role for DM in promoting OA, while others found no significant interactions between these conditions. In this review, we will discuss preclinical and clinical data that assessed the interaction between DM and OA. We will also discuss possible mechanisms associated with the effect of high glucose on the articular cartilage and chondrocytes. An emerging theme dominates the breath of published work in this area: most of the studies discussed in this review do not take into consideration the role of other factors such as the type of diabetes, age, biological sex, type of animal model, body mass index, and the use of pain medications when analyzing and interpreting data. Therefore, future studies should be more rigorous when designing experiments looking at DM and its effects on OA and should carefully account for these confounding factors, so that better approaches can be developed for monitoring and treating patients at risk of OA and DM.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2021

Benchmark estimate of the effect of anthropogenic emissions on the ocean surface

Abstract Investigations into the role of anthropogenic emissions in the occurrence of extreme weather often use a method that compares simulations of atmospheric climate models run under a factual scenario of historical boundary conditions observed during the period of the event against simulations run under a counterfactual scenario of what those boundary conditions might naturally have been over that same period in the absence of anthropogenic emissions. A particular requirement for this experiment design is an accurate estimation of ocean surface boundary conditions for use by the counterfactual natural simulations. Here we use output from the CMIP5 multi‐climate‐model archive to develop a robust estimate of sea surface temperatures and sea ice conditions for use in counterfactual natural simulations, intended as a benchmark estimate to facilitate comparison across climate models and across studies. This development includes tests to ensure that the final estimate is stable from year‐to‐year and stable against other perturbations to the methodology, as well as consideration of the strengths and weaknesses in comparison to other available attributable warming estimates. While this estimate is tailored specifically for the International CLIVAR C20C+ Detection and Attribution Project, it can be used by related projects as well.

Stone, Dáithí A.↗

DOE OSTI2025

Updating Critical Temperature Calculations for Several Secondary High Explosives

In designing experiments where high explosives (HEs) are heated, it is important to have an understanding of where thermal runaway may occur. This determination is often done by using the Frank-Kamenetskii (FK) equation. For several highly-studied HEs, the parameters necessary for FK calculations are typically referenced from decades-old literature, and more recent experimental data have shown that these values require adjustment. For example, some of the legacy parameters dangerously overpredict the critical temperature by tens of degrees relative to more recent observed values. Herein, we first summarize historical results and highlight the importance of insulation effects when estimating critical temperatures for small samples, which is especially relevant to small-scale aging, compatibility, and characterization experiments. Here, we then present updated FK parameters for several common secondary CHNO HEs like RDX, HMX, PETN, and TATB, as well as the first reported values for 2,6-Diamino-3,5-dinitropyrazine-1-oxide (LLM-105). Our updated parameters produce critical-temperature curves that are consistent with both mm-scale differentical scanning calorimetry (DSC) measurements and cm-scale data from the Lawrence Livermore National Laboratory one-dimensional time-to-explosion (ODTX) experiment. In analyzing the critical temperature versus sample size curves derived from the transcendental FK equation, we discovered that these curves are remarkably well described by a simple power-law function with a universal power of 0.142 and a HE-specific scaling factor.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗