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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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All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Effect of Fe on Co-Based SiO2Al2O3 Mixed Support Catalyst for Fischer–Tropsch Synthesis in 3D-Printed SS Microchannel Microreactor

This research explores the effect of a composite support of SiO2 and Al2O3 with Fe and Co incorporated as catalysts for Fischer–Tropsch synthesis (FTS) using a 3D-printed stainless steel (SS) microchannel microreactor. Two mesoporous catalysts, FeCo/SiO2Al2O3 and Co/SiO2Al2O3, were synthesized via a one-pot (OP) method and extensively characterized using N2 physisorption, XRD, SEM, TEM, H2-TPR, TGA-DSC, FTIR, and XPS. H2-TPR results revealed that the synthesis method significantly affected the reducibility of metal oxides, thereby influencing the formation of active FTS sites. SEM-EDS and TEM further revealed a well-defined hexagonal matrix with a porous surface morphology and uniform metal ion distribution. FTS reactions, carried out in the 200–350 °C temperature range at 20 bar with a H2/CO molar ratio of 2:1, exhibited the highest activity for FeCo/SiO2Al2O3, with up to 80% CO conversion. Long-term stability was evaluated by monitoring the catalyst performance for 30 h on stream at 320 °C under identical reaction conditions. The catalyst was initially active for the methanation reaction for up to 15 h, after which the selectivity for CH4 declined. Correspondingly, the C4+ selectivity increased after 15 h of time-on-stream, indicating a shift in the product distribution toward longer-chain hydrocarbons. This trend suggests that the catalyst undergoes gradual activation or restructuring under reaction conditions, which enhances chain growth over time. The increase in C4+ products may be attributed to the stabilization of the active sites and suppression of methane or light hydrocarbon formation.

Biochemistry & Molecular Biology↗
DOE OSTI2020

Reconfiguring Plant Metabolism for Biodegradable Plastic Production

For decades, plants have been the subject of genetic engineering to synthesize novel, value-added compounds. Polyhydroxyalkanoates (PHAs), a large class of biodegradable biopolymers naturally synthesized in eubacteria, are among the novel products that have been introduced to make use of plant acetyl-CoA metabolic pathways. It was hoped that renewable PHA production would help address environmental issues associated with the accumulation of nondegradable plastic wastes. However, after three decades of effort synthesizing PHAs, and in particular the simplest form polyhydroxybutyrate (PHB), and seeking to improve their production in plants, it has proven very difficult to reach a commercially profitable rate in a normally growing plant. This seems to be due to the growth defects associated with PHA production and accumulation in plant cells. Here, we review major breakthroughs that have been made in plant-based PHA synthesis using traditional genetic engineering approaches and discuss challenges that have been encountered. Then, from the point of view of plant synthetic biology, we provide perspectives on reprograming plant acetyl-CoA pathways for PHA production, with the goal of maximizing PHA yield while minimizing growth inhibition. Specifically, we suggest genetic elements that can be considered in genetic circuit design, approaches for nuclear genome and plastome modification, and the use of multiomics and mathematical modeling in understanding and restructuring plant metabolic pathways.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2016

Space telescope and optical reverberation mapping project. IV. Anomalous behavior of the broad ultraviolet emission lines in NGC 5548

During an intensive Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS) UV monitoring campaign of the Seyfert 1 galaxy NGC 5548 performed from 2014 February to July, the normally highly correlated far UV continuum and broad emission line variations decorrelated for ∼60–70 days, starting ∼75 days after the first HST/COS observation. Following this anomalous state, the flux and variability of the broad emission lines returned to a more normal state. This transient behavior, characterized by significant deficits in flux and equivalent width of the strong broad UV emission lines, is the first of its kind to be unambiguously identified in an active galactic nucleus reverberation mapping campaign. The largest corresponding emission line flux deficits occurred for the high ionization, collisionally excited lines C iv and Si iv(+O iv]), and also He ii(+O iii]), while the anomaly in Lyα was substantially smaller. This pattern of behavior indicates a depletion in the flux of photons with E{sub ph}>54 eV relative to those near 13.6 eV. We suggest two plausible mechanisms for the observed behavior: (i) temporary obscuration of the ionizing continuum incident upon broad line region (BLR) clouds by a moving veil of material lying between the inner accretion disk and inner (BLR), perhaps resulting from an episodic ejection of material from the disk, or (ii) a temporary change in the intrinsic ionizing continuum spectral energy distribution resulting in a deficit of ionizing photons with energies >54 eV, possibly due to a transient restructuring of the Comptonizing atmosphere above the disk. Current evidence appears to favor the latter explanation.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

0.7–2.5 μ m Spectra of Hilda Asteroids

The Hilda asteroids are primitive bodies in resonance with Jupiter whose origin and physical properties are not well understood. Current models posit that these asteroids formed in the outer solar system and were scattered along with the Jupiter Trojans into their present-day positions during a chaotic episode of dynamical restructuring. In order to explore the surface composition of these enigmatic objects in comparison with an analogous study of Trojans, we present new near-infrared spectra (0.7–2.5 μ m) of 25 Hilda asteroids. No discernible absorption features are apparent in the data. Synthesizing the bimodalities in optical color and infrared reflectivity reported in previous studies, we classify 26 of the 28 Hildas in our spectral sample into the so-called less-red and red sub-populations and find that the two sub-populations have distinct average spectral shapes. Combining our results with visible spectra, we find that Trojans and Hildas possess similar overall spectral shapes, suggesting that the two minor body populations share a common progenitor population. A more detailed examination reveals that while the red Trojans and Hildas have nearly identical spectra, less-red Hildas are systematically bluer in the visible and redder in the near-infrared than less-red Trojans, indicating a putative broad, shallow absorption feature between 0.5 and 1.0 μ m. We argue that the less-red and red objects found in both Hildas and Trojans represent two distinct surface chemistries and attribute the small discrepancy between less-red Hildas and Trojans to the difference in surface temperatures between the two regions.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2017

Flare Ribbons Approach Observed by the Interface Region Imaging Spectrograph and the Solar Dynamics Observatory

We report flare ribbons approach (FRA) during a multiple-ribbon M-class flare on 2015 November 4 in NOAA AR 12443, obtained by the Interface Region Imaging Spectrograph and the Solar Dynamics Observatory. The flare consisted of a pair of main ribbons and two pairs of secondary ribbons. The two pairs of secondary ribbons were formed later than the appearance of the main ribbons, with respective time delays of 15 and 19 minutes. The negative-polarity main ribbon spread outward faster than the first secondary ribbon with the same polarity in front of it, and thus the FRA was generated. Just before their encounter, the main ribbon was darkening drastically and its intensity decreased by about 70% in 2 minutes, implying the suppression of main-phase reconnection that produced two main ribbons. The FRA caused the deflection of the main ribbon to the direction of secondary ribbon with a deflection angle of about 60°. A post-approach arcade was formed about 2 minutes later and the downflows were detected along the new arcade with velocities of 35–40 km s{sup −1}, indicative of the magnetic restructuring during the process of FRA. We suggest that there are three topological domains with footpoints outlined by the three pairs of ribbons. Close proximity of these domains leads to deflection of the ribbons, which is in agreement with the magnetic field topology.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2026

Changing-look Active Galactic Nuclei Powered by Disk Tearing

Changing-look active galactic nuclei (CLAGN) feature order-of-magnitude variability in both the continuum and broad line luminosities on months-to-years-long timescales, and are currently unexplained. Simulations have demonstrated that rotating black holes (BHs) sometimes tear apart tilted accretion disks. These tearing events violently restructure the disk on timescales much shorter than a viscous timescale, hinting at a connection to CLAGN. Here, we show that disk tearing can power changing-look events. We report synthetic observations of an extremely high-resolution, three-dimensional, general-relativistic magnetohydrodynamic simulation of a geometrically thin, tilted accretion disk around a rapidly rotating, 10 8 M ⊙ BH. We perform ray-tracing calculations that follow the thermal disk emission to both a line-of-sight camera and to a distribution of cameras in a prescribed torus-like broad-line region (BLR). The continuum photoionizes the BLR, and we calculate the resulting spectrum. Both the continuum and line luminosities undergo order-of-magnitude swings on months-to-years-long timescales. We find shorter, week-long variability driven by the geometric precession of the inner disk and an intraday quasiperiodic oscillation driven by radial breathing of the inner disk. When the torn disk precesses, it causes asymmetric illumination of the BLR, driving time-evolving red-to-blue asymmetries of the broad emission lines that may be a smoking gun for disk tearing. We also make predictions for future photometric observations from ULTRASAT and Vera Rubin Observatory, given a Shakura–Sunyaev–like effective temperature profile, both of which may play an important role in detecting future changing-look events. Future work should consider nonthermal emission, especially from the time-variable corona.

accretion↗
DOE OSTI2016

MAGNETIC HELICITY REVERSALS IN A CYCLIC CONVECTIVE DYNAMO

We investigate the role of magnetic helicity in promoting cyclic magnetic activity in a global, 3D, magnetohydrodynamic (MHD) simulation of a convective dynamo. This simulation is characterized by coherent bands of toroidal field that exist within the convection zone, with opposite polarities in the northern hemisphere (NH) and southern hemisphere (SH). Throughout most of the cycle, the magnetic helicity in these bands is negative in the NH and positive in the SH. However, during the declining phase of each cycle, this hemispheric rule reverses. We attribute this to a global restructuring of the magnetic topology that is induced by the interaction of the bands across the equator. This band interaction appears to be ultimately responsible for, or at least associated with, the decay and subsequent reversal of both the toroidal bands and the polar fields. We briefly discuss the implications of these results within the context of solar observations, which also show some potential evidence for toroidal band interactions and helicity reversals.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2012

NREL Quickens its Tech Transfer Efforts

Innovations and 'aha' movements in renewable energy and energy efficiency, while exciting in the lab, only truly live up to their promise once they find a place in homes or business. Late last year President Obama issued a directive to all federal agencies to increase their efforts to transfer technologies to the private sector in order to achieve greater societal and economic impacts of federal research investments. The president's call to action includes efforts to establish technology transfer goals and to measure progress, to engage in efforts to increase the speed of technology transfer and to enhance local and regional innovation partnerships. But, even before the White House began its initiative to restructure the commercialization process, the National Renewable Energy Laboratory had a major effort underway designed to increase the speed and impact of technology transfer activities and had already made sure its innovations had a streamlined path to the private sector. For the last three years, NREL has been actively setting commercialization goals and tracking progress against those goals. For example, NREL sought to triple the number of innovations over a five-year period that began in 2009. Through best practices associated with inventor engagement, education and collaboration, NREL quadrupled the number of innovations in just three years. Similar progress has been made in patenting, licensing transactions, income generation and rewards to inventors. 'NREL is known nationally for our cutting-edge research and companies know to call us when they are ready to collaborate,' William Farris, vice president for commercialization and technology transfer, said. 'Once a team is ready to dive in, they don't want be mired in paperwork. We've worked to make our process for licensing NREL technology faster; it now takes less than 60 days for us to come to an agreement and start work with a company interested in our research.' While NREL maintains a robust patent portfolio, often companies are looking to do more than just license a technology. These relationships are invaluable in successfully moving technologies from NREL to the marketplace. 'We may generate new and potentially valuable innovations, but our commercialization partners do the heavy work of building a successful business around our technology,' Farris said. Tools such as CRADAs (Cooperative Research and Development Agreements) allow NREL to continue working with companies to refine and develop technologies. And, working with businesses is an area where NREL excels. NREL is responsible for one quarter of the CRADAs in the DOE system. 'When you look at the results of our CRADA program, you can demonstrate that we are actively engaged with companies in collaborating on research and moving technologies to market,' Farris said. NREL is first among DOE labs with 186 active CRADAs. And last year, NREL also was first with the number of new CRADAs signed. 'Part of the success in our working with industry goes back to NREL's mission to grow and support new industries,' Farris added. 'NREL has basic research capabilities, but we are never going to be the ultimate producer of a commercial product. That is the role of the private sector.' Farris also credits the advocacy and support that the Office of Energy Efficiency and Renewable Energy at DOE provides for these technology transfer activities. 'EERE's support is critical to our success,' Farris said. To assist the private sector in moving a technology from the lab to the manufacturing line, NREL has a number of programs in place to give that first, or even final, nudge toward commercialization. For instance, the Commercialization Assistance Program helps startups overcome technical barriers by granting free access to 40 hours of work at the lab. Through the Innovation and Entrepreneurship Center, NREL also helps clean energy businesses develop strong links with the financial community, as well as other key stakeholders in the commercialization process. In March, NREL formally opened the Colorado Center for Renewable Energy and Economic Development a cooperative program with the state of Colorado designed to bring together stakeholders and service providers that support the growth of cleantech companies. CREED currently is working with more than 25 stakeholders - governmental partners, universities, industry associations, venture capital organizations and small businesses - to improve the access these groups have to technologies developed at NREL and to provide services such as classes and workshops for entrepreneurs. When it comes to bringing together cleantech stakeholders, NREL's Industry Growth Forum is the marquee event. At the forum, clean energy entrepreneurs have the opportunity to present their business cases to an expert panel of investors and energy executives. Companies that have presented have raised $3.4 billion in funding to date.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2011

Catalytic Partial Oxidation of CH4 over Ni-substituted Barium Hexaaluminate catalysts

Ba{sub 0.75}Ni{sub y}Al{sub 12-y}O{sub 19-{delta}} (y = 0.2, 0.4, 0.6, 0.8 and 1.0) catalysts were tested for the partial oxidation of CH{sub 4} at temperatures between 200 and 900 C. Temperature programmed reaction results indicate that light-off for the partial oxidation reaction occurred between 665 and 687 C for all catalysts. Isothermal runs performed at 900 C on the catalysts showed stable reaction product concentrations, consistent with equilibrium. Post-reaction analysis of the used catalysts showed that there are two distinct zones in the catalyst bed. In a short leading edge of the bed, the apparently complete consumption of oxygen leads to a catalyst which XANES analysis shows is primarily Ni-substituted into the hexaaluminate phase. In the downstream portion of the bed, Ni is shown to be present as metallic Ni. This corresponds to a reaction sequence in which the oxidation of CH{sub 4} proceeds at the inlet until all oxygen is reacted, followed by the reaction of CO{sub 2} and H{sub 2}O with unreacted CH{sub 4}, and its derivatives, to produce the final syngas mixture. From the change in the unit-cell dimensions with Ni substitution, there is a clear indication that Ni{sup 2+}, which has a larger ionic radius than aluminum, substitutes for Al{sup 3+} in the hexaaluminate lattice in the synthesis process, and there is no restructuring of the bulk hexaaluminate phase after the Ni is removed from the lattice.

03 NATURAL GAS↗
DOE OSTI2010

Iron-Air Rechargeable Battery: A Robust and Inexpensive Iron-Air Rechargeable Battery for Grid-Scale Energy Storage

GRIDS Project: USC is developing an iron-air rechargeable battery for large-scale energy storage that could help integrate renewable energy sources into the electric grid. Iron-air batteries have the potential to store large amounts of energy at low cost—iron is inexpensive and abundant, while oxygen is freely obtained from the air we breathe. However, current iron-air battery technologies have suffered from low efficiency and short life spans. USC is working to dramatically increase the efficiency of the battery by placing chemical additives on the battery’s iron-based electrode and restructuring the catalysts at the molecular level on the battery’s air-based electrode. This can help the battery resist degradation and increase life span. The goal of the project is to develop a prototype iron-air battery at significantly cost lower than today’s best commercial batteries.

ARPA-E↗
DOE OSTI2012

Experiences with High-Level Programming Directives for Porting Applications to GPUs

HPC systems now exploit GPUs within their compute nodes to accelerate program performance. As a result, high-end application development has become extremely complex at the node level. In addition to restructuring the node code to exploit the cores and specialized devices, the programmer may need to choose a programming model such as OpenMP or CPU threads in conjunction with an accelerator programming model to share and manage the difference node resources. This comes at a time when programmer productivity and the ability to produce portable code has been recognized as a major concern. In order to offset the high development cost of creating CUDA or OpenCL kernels, directives have been proposed for programming accelerator devices, but their implications are not well known. In this paper, we evaluate the state of the art accelerator directives to program several applications kernels, explore transformations to achieve good performance, and examine the expressiveness and performance penalty of using high-level directives versus CUDA. We also compare our results to OpenMP implementations to understand the benefits of running the kernels in the accelerator versus CPU cores.

43 PARTICLE ACCELERATORS↗
DOE OSTI2011

Global Arrays Parallel Programming Toolkit

The two predominant classes of programming models for parallel computing are distributed memory and shared memory. Both shared memory and distributed memory models have advantages and shortcomings. Shared memory model is much easier to use but it ignores data locality/placement. Given the hierarchical nature of the memory subsystems in modern computers this characteristic can have a negative impact on performance and scalability. Careful code restructuring to increase data reuse and replacing fine grain load/stores with block access to shared data can address the problem and yield performance for shared memory that is competitive with message-passing. However, this performance comes at the cost of compromising the ease of use that the shared memory model advertises. Distributed memory models, such as message-passing or one-sided communication, offer performance and scalability but they are difficult to program. The Global Arrays toolkit attempts to offer the best features of both models. It implements a shared-memory programming model in which data locality is managed by the programmer. This management is achieved by calls to functions that transfer data between a global address space (a distributed array) and local storage. In this respect, the GA model has similarities to the distributed shared-memory models that provide an explicit acquire/release protocol. However, the GA model acknowledges that remote data is slower to access than local data and allows data locality to be specified by the programmer and hence managed. GA is related to the global address space languages such as UPC, Titanium, and, to a lesser extent, Co-Array Fortran. In addition, by providing a set of data-parallel operations, GA is also related to data-parallel languages such as HPF, ZPL, and Data Parallel C. However, the Global Array programming model is implemented as a library that works with most languages used for technical computing and does not rely on compiler technology for achieving parallel efficiency. It also supports a combination of task- and data-parallelism and is available as an extension of the message passing (MPI) model. The GA model exposes to the programmer the hierarchical memory of modern high-performance computer systems, and by recognizing the communication overhead for remote data transfer, it promotes data reuse and locality of reference. Virtually all the scalable architectures possess non-uniform memory access characteristics that reflect their multi-level memory hierarchies. These hierarchies typically comprise processor registers, multiple levels of cache, local memory, and remote memory. Over time, both the number of levels and the cost (in processor cycles) of accessing deeper levels has been increasing. It is important for any scalable programming model to address memory hierarchy since it is critical to the efficient execution of scalable applications.

ARMCI↗
DOE OSTI2016

Engineering Platinum Alloy Electrocatalysts in Nanoscale for PEMFC Application

Fuel cells are expected to be a key next-generation energy source used for vehicles and homes, offering high energy conversion efficiency and minimal pollutant emissions. However, due to large overpotentials on anode and cathode, the efficiency is still much lower than theoretically predicted. During the past decades, considerable efforts have been made to investigate synergy effect of platinum alloyed with base metals. But, engineering the alloy particles in nanoscale has been a challenge. Most important challenges in developing nanostructured materials are the abilities to control size, monodispersity, microcomposition, and even morphology or self-assembly capability, so called Nanomaterials-by-Design, which requires interdisciplinary collaborations among computational modeling, chemical synthesis, nanoscale characterization as well as manufacturing processing. Electrocatalysts, particularly fuel cell catalysts, are dramatically different from heterogeneous catalysts because the surface area in micropores cannot be electrochemically controlled on the same time scale as more transport accessible surfaces. Therefore, electrocatalytic architectures need minimal microporous surface area while maximizing surfaces accessible through mesopores or macropores, and to "pin" the most active, highest performance physicochemical state of the materials even when exposed to thermodynamic forces, which would otherwise drive restructuring, crystallization, or densification of the nanoscale materials. In this presentation, results of engineering nanoscale platinum alloy particles down to 2 ~ 4 nm will be discussed. Based on nature of alloyed base metals, various synthesis technologies have been studied and developed to achieve capabilities of controlling particle size and particle microcomposition, namely, core-shell synthesis, microemulsion technique, thermal decomposition process, surface organometallic chemical method, etc. The results show that by careful engineering the particle size and microcomposition in nanoscale, it is able to achieve superior electrocatalytic activities comparing with traditional preparative methods. Examples to be discussed are high surface area carbon supported Pt, PtM binary, and PtMN ternary alloys, their synthesis processes, characterizations and electrocatalytic activities towards molecular oxygen reduction.

Alloy↗
DOE OSTI2018

Spatially Explicit Modeling of Criteria Air Pollutants from Agricultural and Forestry Feedstock Production

The Feedstock Production Emissions to Air Model (FPEAM) is a spatially explicit supply chain model that quantifies criteria air pollutants and precursors generated by biomass production, harvest and transportation to biorefineries. FPEAM was most recently used for the 2016 Billion Ton Study (BTS) published by the U.S. Department of Energy Bioenergy Technologies Office. This presentation describes several use cases for the model, and provides an overview of recent restructuring that increases FPEAM's usability and functionality. FPEAM currently estimates emissions of volatile organic compounds, particulate matter, nitrogen oxides, sulfur oxides, and carbon monoxide from on-farm equipment operation, on-farm fugitive dust, on-farm chemical (fertilizer, herbicide and insecticide) application, and biomass transportation. These calculations are implemented within FPEAM as modules, which independently perform calculations for each emissions category. This structure allows users to include or exclude emissions categories according to the goal and scope of their analysis. Each module's input data defines the activities taking place with information including fuel combusted, chemicals applied, and equipment used. Users can replace or augment the default input data to quantify additional pollutant types, emissions categories, farming practices and biomass types. Emissions from biomass transportation and on-farm equipment operation are by default calculated by the U.S. Environmental Protection Agency's Motor Vehicle Emission Simulator (MOVES) and NONROAD model, respectively. These models - which are computationally intensive but provide detailed results - can optionally be replaced with user-provided emissions factors for fuel combustion and vehicle operation. This approach reduces FPEAM's runtime and allows users to run sensitivity analyses around biomass production and transportation scenarios. Other enhancements currently under development are the use of farm-to-biorefinery route information to increase the spatial resolution of transportation emissions, and a module to connect FPEAM and the Intervention Model for Air Pollution (InMAP), which will enable the quantification of human health impacts.

09 BIOMASS FUELS↗
DOE OSTI2017

Studying Unirradiated TRISO-coated Particles from the Second Advanced Gas Reactor Experiment

Combined precession electron diffraction and point resolved chemical imaging have been used to provide an analysis of the material structure and chemical information of unirradiated uranium oxy-carbide (14.0 wt% enriched) kernelled tristructural isotropic-coated (TRISO) coated particle fuel. The detailed microstructural analysis includes examination of the structure associated with kernel, IPyC and SiC layers, as well as the IPyC-SiC interface. The analysis serves as a baseline for future studies on the potential effects of fission product and defect release through intact SiC layers and possible grain restructuring with irradiation. The baseline microstructure is thereby identified to understand the subtle effects of fabrication that may influence fission product precipitate release associated with different fuel types. Results indicated a Si:C gradient in the SiC layer which could influence fission transport reactivity and the high resolution imaging at the IPyC-SiC interface shows the gradual chemical composition change at this interface.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2020

Municipal Adaptation to Changing Curbside Demands: Findings from Semi-Structured Interviews with Ten U.S. Cities

Emerging mobility services (e.g. ride-hailing, e-commerce, micro-mobility, etc.), are generating novel and rapidly growing demands to use curbside space, with potentially large impacts on mobility, energy consumption, and related outcomes. This presents both opportunities and challenges to municipal agencies responsible for managing this interface between the road network and adjacent land uses, as legacy practices require updating. In this study, we employ a semi-structured interviewing approach to establish how municipalities are adapting to these new pressures on their curbside. We interviewed senior staff responsible for curbside policy of ten large U.S. municipalities, with populations ranging from ~250,000 to ~5,000,000 (and the majority of which are the central city of their metropolitan region). We document a trend of organizational restructuring to more formally include curbside management teams, with the majority of interviewees also reporting increased staffing. Respondents reported that operational failures at their curbside (e.g. demand in excess of capacity) have impacts on safety, capacity, and emergency vehicle mobility, with impacts highly concentrated spatially and temporally (e.g. late evenings in nightlife districts). We document a diversity of data flows between ride-hailing operators (e.g. Uber, Lyft) and municipalities, with some cities reporting obtaining types of data that other cities report not receiving, despite requesting such data. Finally, respondents consistently expressed a desire for new data streams and methodologies to help manage the curbside of the future. It is hoped that establishing the state of practice in this rapidly changing context will be of use to practitioners facing similar pressures as those of our interviewees.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2020

Geomancy: Automated Performance Enhancement through Data Layout Optimization

Large distributed storage systems such as high- performance computing (HPC) systems used by national or international laboratories require sufficient performance and scale for demanding scientific workloads and must handle shifting workloads with ease. Ideally, data is placed in locations to optimize performance, but the size and complexity of large storage systems inhibit rapid effective restructuring of data layouts to maintain performance as workloads shift. To address these issues, we have developed Geomancy, a tool that models the placement of data within a distributed storage system and reacts to drops in performance. Using a combination of machine learning techniques suitable for temporal modeling, Geomancy determines when and where a bottleneck may happen due to changing workloads and suggests changes in the layout that mitigate or prevent them. Our approach to optimizing throughput offers benefits for storage systems such as avoiding potential bottlenecks and increasing overall I/O throughput from 11% to 30%.

Bel, Oceane M.↗
DOE OSTI2020

Design of RUSL Irradiation Experiment with Free Standing Sample

During FY19, the MIMIC-RUSL TREAT test successfully measured the shift in resonance of a cantilever beam as it underwent a grain restructuring event in the TREAT reactor core. FY20 efforts focused on a new capsule design which would replace the cantilever beam with a free-free beam. The free-free beam configuration eliminates the cantilever boundary condition and enables internal friction measurements. A test capsule was designed which supported the sample beam at the nodal points of the first flexural vibration mode. Initial tests detected the resonance peak but the signal to noise level was not high enough for in-situ measurements. Several detection probes were tested and a significant increase in the signal to noise was achieved. Although adequate signals and clean resonance peaks were measured when the beam was centered, the beam did not self-center when displaced resulting in distorted and inconsistent resonance peaks. It was concluded that the free-free beam approach is likely not suited for in-situ measurements. Measurement of ZGV plate waves is another option for in-situ microstructure monitoring and should be considered for future work.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗