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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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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Perspectives on Microfluidics for the Study of Asphaltenes in Upstream Hydrocarbon Production: A Minireview

The utilization of microfluidics has generated deep insights into asphaltene precipitation mechanisms and oil–water emulsion stabilization. Agglomeration and precipitation of asphaltenes can cause flow assurance problems during the extraction and transportation of crude oil. Change in temperature, pressure, reservoir conditions, and solvents can change the local environment, leading to asphaltene precipitation. Understanding asphaltene properties and precipitation pathways becomes critical in devising mitigation methods, demulsifiers, and suitable conditions during hydrocarbon processing. Microfluidics has helped in high throughput measurement studies, understanding critical processing conditions, fast demulsifier screening, and the effect of solvent concentration on deposition, generating useful information for utilization at the point of resource extraction facilitating improved resource management. It has become possible to capture the porous, complex nature of reservoir formations and the interaction of chemicals during precipitation through integrated analytics and visualization studies available only through microfluidics. The use of droplet microfluidics, with optical microscopy and high-speed imaging to study the oil–water interface, has resulted in greater understanding of the role of asphaltenes in interfacial properties and emulsion stabilization. Here, this minireview highlights the crucial aspects of microfluidics that have been used to understand physicochemical behavior and dynamics of asphaltene deposition. Some of the unique devices have been presented focusing on the key elements of microfluidics design, fabrication, and analysis, as the insight obtained from microfluidics strongly depends on the device design and the controllability of the experimental parameters. Successful implementation of microfluidics for efficient and controlled experiments, short analysis time scales and rapid screening, and generation of high-quality, reliable data that convey asphaltene deposition issues and interface behavior in emulsions shows the importance of microsystems for advancing knowledge in hydrocarbon production and processing.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Machine learning for modern power distribution systems: Progress and perspectives

The application of machine learning (ML) to power and energy systems (PES) is being researched at an astounding rate, resulting in a significant number of recent additions to the literature. As the infrastructure of electric power systems evolves, so does interest in deploying ML techniques to PES. However, despite growing interest, the limited number of reported real-world applications suggests that the gap between research and practice is yet to be fully bridged. To help highlight areas where this gap could be narrowed, this article discusses the challenges and opportunities in developing and adapting ML techniques for modern electric power systems, with a particular focus on power distribution systems. These systems play a crucial role in transforming the electric power sector and accommodating emerging distributed technologies to mitigate the impacts of climate change and accelerate the transition to a sustainable energy future. The objective of this article is not to provide an exhaustive overview of the state-of-the-art in the literature, but rather to make the topic accessible to readers with an engineering or computer science background and an interest in the field of ML for PES, thereby encouraging cross-disciplinary research in this rapidly developing field. To this end, the article discusses the ways in which ML can contribute to addressing the evolving operational challenges facing power distribution systems and identifies relevant application areas that exemplify the potential for ML to make near-term contributions. At the same time, key considerations for the practical implementation of ML in power distribution systems are discussed, along with suggestions for several potential future directions.

Marković, Marija (ORCID:0000000247839837)↗
DOE OSTI2021

The Pollica perspective on the (super)-conformal world

This manuscript samples a series of recent results in the quest for a systematic understanding of the space of conformal field theories, with a particular focus on theories with extended supersymmetry. The large majority of results reported here were presented during the second Pollica summer workshop which took place from June 3–21 2019 and focused on mathematical and geometric tools for superconformal field theories. Furthermore, this manuscript represents in many ways a partial summary of the workshop.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

Entanglement perspective on the quantum approximate optimization algorithm

Many quantum algorithms seek to output a specific bitstring solving the problem of interest—or a few if the solution is degenerate. It is the case for the quantum approximate optimization algorithm (QAOA) in the limit of large circuit depth, which aims to solve quadratic unconstrained binary optimization problems. Hence, the expected final state for these algorithms is either a product state or a low-entangled superposition involving a few bitstrings. What happens in between the initial N -qubit product state | 0 〉 ⊗ N and the final one regarding entanglement? Here, we consider the QAOA algorithm for solving the paradigmatic MaxCut problem on different types of graphs. We study the entanglement growth and spread resulting from randomized and optimized QAOA circuits and find that there is a volume-law entanglement barrier between the initial and final states. We also investigate the entanglement spectrum in connection with random matrix theory. In addition, we compare the entanglement production with a quantum annealing protocol aiming to solve the same MaxCut problems. Finally, we discuss the implications of our results for the simulation of QAOA circuits with tensor network-based methods relying on low-entanglement for efficiency, such as matrix product states.

Dupont, Maxime↗
DOE OSTI2020

Insights into negative differential resistance in MoS 2 Esaki diodes: A first-principles perspective

MoS 2 is a two-dimensional material with a band gap depending on the number of layers and tunable by an external electric field. The experimentally observed intralayer band-to-band tunneling and interlayer band-to-band tunneling in this material present an opportunity for new electronic applications in tunnel field-effect transistors. However, such a widely accepted concept has yet to be been supported by theoretical investigations based on first principles. In this paper, using density functional theory, in conjunction with nonequilibrium Green's function techniques and our electric field gating method, enabled by a large-scale computational approach, we study the relation between band alignment and transmission in planar and side-stack MoS 2 p–i–n junction configurations. Here, we demonstrate the presence of negative differential resistance for both in-plane and interlayer current, a staple characteristic of tunnel diode junctions, and analyze the physical origin of such an effect. Electrostatic potentials, the van der Waals barrier, and a complex band analysis are also examined for a thorough understanding of Esaki diodes.

74 ATOMIC AND MOLECULAR PHYSICS↗
NASA NTRS2010

NASA Perspectives on Earth Observations from Satellite or 50 Years of Meteorological Satellite Experiments-The NASA Perspective

The NASA was established in 1959. From those very eady days to the present NASA has been intimately involved with NOAA and the scientific community in the development and operation of satellite and sensor experiments. The early efforts included experiments on the TIROS and geostationary Applications Technology Satellites (ATS) series. In the latter case the spin-scan cameras conceived by Verner Suomi, along with the TIROS cameras, opened new vistas at what could be done in meteorological studies with the daily, nearly global, synoptic views from space-borne sensors As the years passed and the Nimbus series of satellites came into being in the 1960's, more quantitative observations with longer-lifetime, increasingly capable, better calibrated instruments came into being. NASA, in collaboration with and in support of NOAA, implemented operational systems that we now know as the Polar Operational Environmental Satellite (POES) series and the Geostationary Operational Environmental Satellite (GOES) series that provided dependable, continuous, dedicated satellite observations for use by the weather and atmospheric science communities. Through the 1970's, 1980's, and 1990's improved, well-calibrated instruments with more spectral bands extending into the thermal and the microwave portions of the electromagnetic spectrum were provided to obtain accurate soundings of the atmosphere, atmospheric chemistry constituents such as ozone, global sea surface temperature, snow and ice extent, vegetation dynamics, etc. In the 1990's and up to the present the NASA/Earth Observing System (EOS) has been developed, implemented, and operated over many years to provide a very comprehensive suite of observations of the atmosphere, as well as land and ocean parameters. The future looks bright wherein the development of new systems, broadly described by the National Academy of Science Decadal Study, is now underway. NASA, along with collaborations with NOAA, other agencies, and the scientific and applications communities looks forward to achieving in the years to come goals possible with the global information provided by satellites and continuously improved with technology development, joint data assimilation efforts, and attendant research studies.

Einaudi, Franco↗
NASA NTRS1984

Influence of a perspective cockpit traffic display format on pilot avoidance maneuvers

Perspective projections of cockpit displays of traffic information (CDTI) on CRTs to present vertical separation information to airline pilots were examined. The perspective projection was compared with plan view projections of the same air traffic situations. Comparison of the pilots' avoidance maneuvers made when using the perspective display with those made while using more the conventional plan view display showed that pilots maneuvered somewhat earlier with perspective displays. With the perspective display, they maneuvered more frequently in the vertical dimension. The bias to maneuver horizontally probably reflected the poorer presentation of vertical separation on previously used plan view traffic displays. The avoidance decisions made by pilots using both perspective and plan view displays shows fewer unsuccessful maneuvers and fewer maneuvers producing spacing violations with the perspective format.

Ellis, S. R.↗
NASA NTRSDate not supplied

A Spectrum of Stakeholder Perspective Taking in Early-Stage Design

Stakeholder perspective taking is a critical skill in early-stage problem exploration and framing. We examined stakeholder perspective taking within a professional engineering early-stage design team at NASA to begin to understand in what ways and under what conditions designers adopt stakeholder perspectives. Our findings identify a spectrum of perspective taking during problem framing deliberations that ranges from (1) fully taking the stakeholder’s point of view (POV), (2) interpreting the stakeholder’s POV with a designer’s POV, (3) implanting the stakeholder’s POV into a designer’s POV, to (4) fully taking a designer’s own POV. We also begin to identify and describe conditions that encourage and hinder stakeholder perspective taking in real-world early-stage design settings. These findings are significant because they suggest ways to gauge and encourage the skill of perspective taking among highly technical engineers working on design challenges with real-world, societal implications.

perspective taking↗
NASA NTRS1987

Perspective traffic display format and airline pilot traffic avoidance

Part-task experiments have examined perspective projections of cockpit displays of traffic information as a means of presenting aircraft separation information to airline pilots. Ten airline pilots served as subjects in an experiment comparing the perspective projection with plan-view projections of the same air traffic situations. The pilots' task was to monitor the traffic display in order to decide if an avoidance maneuver was needed. Pilots took more time to select avoidance maneuvers with a conventional plan-view display than with an experimental perspective display. In contrast to previous results, if the pilots selected a maneuver with the perspective display, they were more likely to choose one with a vertical component. Tabulation of the outcomes of their initial avoidance decisions with both perspective and plan-view displays showed that they were more likely to achieve required separation with maneuvers chosen with the aid of perspective displays.

Ellis, Stephen R.↗
NASA NTRSDate not supplied

AIAA ASCEND 2023 Panel Session Proposal: Community Perspectives on Establishing a Government-Funded National Laboratory in a Commercially-Driven LEO Ecosystem

AIAA ASCEND 2023 Panel Session Proposal: Community Perspectives on Establishing a Government-Funded National Laboratory in a Commercially-Driven LEO Ecosystem Submitted by the NASA Office of Technology, Policy, and Strategy March 8, 2023 Session Format: Panel Session Topic: Expanding and Evolving the Space Economy Session Title: Community Perspectives on Establishing a Government-Funded National Laboratory in a Commercially-Driven LEO Ecosystem Short Session Description: NASA is preparing for the retirement of the ISS and transition of government-sponsored low-Earth orbit (LEO) activities to Commercial LEO Destinations (CLDs), which includes a government-funded national lab. This transition necessitates new models to connect government-funded users of the LEO environment to CLDs. This panel will highlight updates on what may constitute a national laboratory, share perspectives from members of LEO user communities, and open the discussion for additional comments. Requested Session Duration: 90 minutes Extended Session Description: NASA is preparing for the retirement of the ISS and transition of low-Earth orbit (LEO) activities to Commercial LEO Destinations (CLDs), including planning for a national laboratory. This transition necessitates new models for connecting government-funded users of the LEO environment to CLDs. NASA has made progress on models and a stepwise strategy to enable this national laboratory. This session will discuss guiding national strategies and highlight perspectives on what constitutes a national laboratory from current user communities. A NASA panel participant will introduce the rationale for continuing a national laboratory utilizing CLDs and speak on progress-to-date. This includes furthering national priorities to continue a space-based microgravity national laboratory. It also may include a brief overview of a study conducted by NASA which elucidates a trade space of models for a national laboratory and highlights from an interagency working group on microgravity for additional context. A moderator and five panelists representing diverse LEO user communities will then share perspectives on topics relating to this new dynamic ecosystem, expectations for models and activities, and other thoughts on NASA’s progress. Panelists may consist of members from the following communities: NASA, other U.S. government agencies, startups, small businesses, academia, and non-profits. The panel then plans to open discussion to the audience for questions, input, and additional feedback. Session Goal(s)/Outcome(s): By hosting a panel session, NASA aims to accomplish two goals. First, NASA wishes to update the community on progress towards establishing a national laboratory in low-Earth orbit. This includes sharing key perspectives heard from stakeholder communities. The second goal is to highlight the collaborative nature of such an undertaking and to facilitate additional discussion with other current and future users of the LEO community. Participants (not exhaustive): Erica Rodgers; Robyn Gatens

Erica Marie Rodgers Heusinkveld↗