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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 OSTI2016

Lidar-Enhanced Wind Turbine Control: Past, Present, and Future

The main challenges in harvesting energy from the wind arise from the unknown incoming turbulent wind field. Balancing the competing interests of reduction in structural loads and increasing energy production is the goal of a wind turbine controller to reduce the cost of producing wind energy. Conventional wind turbines use feedback methods to optimize these goals, reacting to wind disturbances after they have already impacted the wind turbine. Lidar sensors offer a means to provide additional inputs to a wind turbine controller, enabling new techniques to improve control methods, allowing a controller to actuate a wind turbine in anticipation of an incoming wind disturbance. This paper will look at the development of lidar-enhanced controls and how they have been used for various turbine load reductions with pitch actuation, as well as increased energy production with improved yaw control. Ongoing work will also be discussed to show that combining pitch and torque control using feedforward nonlinear model predictive control can lead to both reduced loads and increased energy production. Future work is also proposed on extending individual wind turbine controls to the wind plant level and determining how lidars can be used for control methods to further lower the cost of wind energy by minimizing wake impacts in a wind farm.

17 WIND ENERGY↗
NASA NTRS1959

Space: Past, Present, and Future: for Presentation to the American Ordnance Association, Washington Post

It is obvious that the last decade has produced dramatic changes in our national viewpoints on the question of the exploration of space. I would like to refer back, as a starting point, to a series of tests which were performed in 1949 under the sponsorship of the Army Ordnance Department under the code name, "Bumper." This project was carried out jointly by the Jet Propulsion Laboratory, the General Electric Company, and the Douglas Aircraft Company. The object of the project was to launch a Wac Corporal upper-stage vehicle from a V-2, and demonstrate a prototype high-performance, multi-stage rocket vehicle system. As you may recall, the project was entirely successful in demonstrating the feasibility of several unproved concepts: the staging of rocket vehicles at high altitudes, the utility of ablative materials for protection from aerodynamic heating, and a method of stabilizing rocket propelled vehicles operating in the vacuum of space. One of the most significant interpretations of this test to the engineers familiar with the work was the fact that the test showed that there were no longer any purely scientific barriers to the construction of vehicles capable of space flight. The barrier was engineering.

Stewart, Homer J.↗
NASA NTRSDate not supplied

Trends in Small Satellite Presentations from 2017-2019

As the small satellite community expands and new technologies emerge, it is important to understand and interpret these changes over time. In doing so, we observe progress and aid future development within the field. During the summer of 2020 we compiled for assessment purposes, archived presentation data for years 2017-2019 from three primary sources: the CubeSat Developers Workshop, Interplanetary Small Satellite Conference, and the Small Satellite Conference. A few examples of the information we recorded and compiled were presenter names and affiliations, presentation topic, and mission progress status. Ultimately, we reviewed roughly 600 presentations between the three conferences and the data obtained therein form the basis of our trend assessment. The paper focuses on trends interpreted through the assessment of key elements available in the content of each presentation to include: SmallSat mission developers, subsystem developments and the expanded scope for small satellite destinations. Data was generalized using various forms of analysis depending on the type of information being assessed. In the end, we achieved our goal of reducing the content to its key points and major takeaways from the conference proceedings. In this presentation, the observed trends in data and our findings will be discussed. First, we will cover changes in presentation topics by categorizing them as either: science, technology, science/technology, or other. Our next topic will be about the agencies and organizations at the forefront of small satellite research and development. The following section will explain trends in subsystem developments for telecommunications, propulsion, power, and thermal management. Further discussion will highlight how the scope of interplanetary spaceflight has expanded since 2017 as new small spacecraft missions venture beyond low-Earth orbit into deep space exploration. And finally, we will observe what information was lacking in archived presentations which included but not limited to: mission’s funding source, presentation focus area, and software used.

Small Satellite↗
NASA NTRSDate not supplied

Trends in Small Satellite Presentations from 2017 - 2019

As the small satellite community expands and new technologies emerge, it is important to understand and interpret these changes over time. In doing so, we observe progress and aid future development within the field. During the summer of 2020 we compiled for assessment purposes, archived presentation data for years 2017-2019 from three primary sources: the CubeSat Developers Workshop, Interplanetary Small Satellite Conference, and the Small Satellite Conference. A few examples of the information we recorded and compiled were presenter names and affiliations, presentation topic, and mission progress status. Ultimately, we reviewed roughly 600 presentations between the three conferences and the data obtained therein form the basis of our trend assessment. The paper focuses on trends interpreted through the assessment of key elements available in the content of each presentation to include: SmallSat mission developers, subsystem developments and the expanded scope for small satellite destinations. Data was generalized using various forms of analysis depending on the type of information being assessed. In the end, we achieved our goal of reducing the content to its key points and major takeaways from the conference proceedings. In this presentation, the observed trends in data and our findings will be discussed. First, we will cover changes in presentation topics by categorizing them as either: science, technology, science/technology, or other. Our next topic will be about the agencies and organizations at the forefront of small satellite research and development. The following section will explain trends in subsystem developments for telecommunications, propulsion, power, and thermal management. Further discussion will highlight how the scope of interplanetary spaceflight has expanded since 2017 as new small spacecraft missions venture beyond low-Earth orbit into deep space exploration. And finally, we will observe what information was lacking in archived presentations which included but not limited to: mission’s funding source, presentation focus area, and software used.

Small Satellites↗
DOE OSTI2018

Assessment of the combination of temperature and relative humidity on kidney stone presentations

Highlights: • Temperature and relative humidity have opposing effects on evaporative water loss. • Wet-bulb temperatures best predicted kidney stone presentations. • Differences in predictive capacity of temperature metrics were greatest in summer. Temperature and relative humidity have opposing effects on evaporative water loss, the likely mediator of the temperature-dependence of nephrolithiasis. However, prior studies considered only dry-bulb temperatures when estimating the temperature-dependence of nephrolithiasis. We used distributed lag non-linear models and repeated 10-fold cross-validation to determine the daily temperature metric and corresponding adjustment for relative humidity that most accurately predicted kidney stone presentations during hot and cold periods in South Carolina from 1997 to 2015. We examined three metrics for wet-bulb temperatures and heat index, both of which measure the combination of temperature and humidity, and for dry-bulb temperatures: (1) daytime mean temperature; (2) 24-h mean temperature; and (3) most extreme 24-h temperature. For models using dry-bulb temperatures, we considered four treatments of relative humidity. Among 188,531 patients who presented with kidney stones, 24-h wet bulb temperature best predicted kidney stone presentation during summer. Mean cross-validated residuals were generally lower in summer for wet-bulb temperatures and heat index than the corresponding dry-bulb temperature metric, regardless of type of adjustment for relative humidity. Those dry-bulb models that additionally adjusted for relative humidity had higher mean residuals than other temperature metrics. The relative risk of kidney stone presentations at the 99th percentile of each temperature metric compared to the respective median temperature in summer months differed by temperature metric and relative humidity adjustment, and ranged from an excess risk of 8–14%. All metrics performed similarly in winter. The combination of temperature and relative humidity determine the risk of kidney stone presentations, particularly during periods of high heat and humidity. These results suggest that metrics that measure moist heat stress should be used to estimate the temperature-dependence of kidney stone presentations, but that the particular metric is relatively unimportant.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS2013

Preindustrial to Present-Day Changes in Tropospheric Hydroxyl Radical and Methane Lifetime from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)

We have analysed time-slice simulations from 17 global models, participating in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP), to explore changes in present-day (2000) hydroxyl radical (OH) concentration and methane (CH4) lifetime relative to preindustrial times (1850) and to 1980. A comparison of modeled and observation-derived methane and methyl chloroform lifetimes suggests that the present-day global multi-model mean OH concentration is overestimated by 5 to 10% but is within the range of uncertainties. The models consistently simulate higher OH concentrations in the Northern Hemisphere (NH) compared with the Southern Hemisphere (SH) for the present-day (2000; inter-hemispheric ratios of 1.13 to 1.42), in contrast to observation-based approaches which generally indicate higher OH in the SH although uncertainties are large. Evaluation of simulated carbon monoxide (CO) concentrations, the primary sink for OH, against ground-based and satellite observations suggests low biases in the NH that may contribute to the high north–south OH asymmetry in the models. The models vary widely in their regional distribution of present-day OH concentrations (up to 34%). Despite large regional changes, the multi-model global mean (mass-weighted) OH concentration changes little over the past 150 yr, due to concurrent increases in factors that enhance OH (humidity, tropospheric ozone, nitrogen oxide (NOx) emissions, and UV radiation due to decreases in stratospheric ozone), compensated by increases in OH sinks (methane abundance, carbon monoxide and non-methane volatile organic carbon (NMVOC) emissions). The large inter-model diversity in the sign and magnitude of preindustrial to present-day OH changes (ranging from a decrease of 12.7% to an increase of 14.6%) indicate that uncertainty remains in our understanding of the long-term trends in OH and methane lifetime. We show that this diversity is largely explained by the different ratio of the change in global mean tropospheric CO and NOx burdens (Delta CO/Delta NOx, approximately represents changes in OH sinks versus changes in OH sources) in the models, pointing to a need for better constraints on natural precursor emissions and on the chemical mechanisms in the current generation of chemistry-climate models. For the 1980 to 2000 period, we find that climate warming and a slight increase in mean OH (3.5 +/- 2.2%) leads to a 4.3 +/- 1.9% decrease in the methane lifetime. Analysing sensitivity simulations performed by 10 models, we find that preindustrial to present-day climate change decreased the methane lifetime by about four months, representing a negative feedback on the climate system. Further, we analysed attribution experiments performed by a subset of models relative to 2000 conditions with only one precursor at a time set to 1860 levels. We find that global mean OH increased by 46.4 +/- 12.2% in response to preindustrial to present-day anthropogenic NOx emission increases, and decreased by 17.3 +/-2.3%, 7.6 +/- 1.5%, and 3.1 +/- 3.0% due to methane burden, and anthropogenic CO, and NMVOC emissions increases, respectively.

nitrogen oxides↗
DOE OSTI2021

HydrogenAR: Interactive Data-Driven Presentation of Dispenser Reliability: Preprint

When delivering presentations to a co-located audience, we typically use slides with text and 2D graphics to complement the spoken narrative. Though presentations have largely been explored on 2D media, augmented reality (AR) allows presentation designers to add data and augmentations to existing physical infrastructure on display. This could provide a more engaging experience to the audience and support comprehension. With HydrogenAR, we present a novel application that leverages the benefits of data-driven storytelling with those of AR to explain the unique challenges of hydrogen dis- penser reliability. Utilizing physical props, situated data, and virtual augmentations and animations, HydrogenAR serves as a unique presentation tool, particularly critical for stakeholders, tour groups, and VIPs. HydrogenAR is a product of multiple collaborative de- sign iterations with a local Hydrogen Fuel research team and is evaluated through interviews with team members and a user study with end-users to evaluate the usability and quality of the interactive AR experience. Through this work, we provide design considera- tions for AR data-driven presentations and discuss how AR could be used for innovative content delivery beyond traditional slide-based presentations.

augmented reality↗
DOE OSTI2017

Causes and importance of new particle formation in the present-day and preindustrial atmospheres

New particle formation has been estimated to produce around half of cloud-forming particles in the present-day atmosphere, via gas-to-particle conversion. Here we assess the importance of new particle formation (NPF) for both the present-day and the preindustrial atmospheres. We use a global aerosol model with parametrizations of NPF from previously published CLOUD chamber experiments involving sulfuric acid, ammonia, organic molecules, and ions. We find that NPF produces around 67% of cloud condensation nuclei at 0.2% supersaturation (CCN0.2%) at the level of low clouds in the preindustrial atmosphere (estimated uncertainty range 45–84%)and 54% in the present day (estimated uncertainty range 38–66%). Concerning causes, we find that the importance of biogenic volatile organic compounds(BVOCs) in NPF and CCN formation is greater than previously thought. Removing BVOCs and hence all secondary organic aerosol from our model reduces low-cloud-level CCN concentrations at 0.2%supersaturation by 26% in the present-day atmosphere and 41% in the preindustrial. Around three quarters of this reduction is due to the tiny fraction of the oxidation products of BVOCs that have sufficiently low volatility to be involved in NPF and early growth. Furthermore, we estimate that 40% of preindustrial CCN0.2% are formed via ion-induced NPF, compared with 27% in the present day, although we caution that the ion-induced fraction of NPF involving BVOCs is poorly measured at present. In conclusion, our model suggests that the effect of changes in cosmic ray intensity on CCN is small and unlikely to be comparable to the effect of large variations in natural primary aerosol emissions.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS2004

An Educational Multimedia Presentation on the Introduction to Spacecraft Charging

Over the last few decades, significant knowledge has been gained in how to protect spacecraft from charging; however, the continuing technical advancement in the design and build of satellites requires on-going effort in the study of spacecraft charging. A situation that we have encountered is that not all satellite designers and builders are familiar with the problem of spacecraft charging. The design of a satellite involves many talented people with diverse backgrounds, ranging from manufacturing and assembly to engineering and program management. The complex design and build of a satellite system requires people with highly specialized skills such that cross-specialization is often not achievable. As a result, designers and builders of satellites are not usually familiar with the problems outside their specialization. This is also true for spacecraft charging. Not everyone is familiar with the definition of spacecraft charging and the damage that spacecraft charging can cause. Understanding the problem is an important first step in getting everyone involved in addressing the appropriate spacecraft charging issues during the satellite design and build phases. To address this important first step, an educational multimedia presentation has been created to inform the general engineering community about the basics of spacecraft charging. The content of this educational presentation is based on relevant published technical papers. The presentation was developed using Macromedia Flash. This software produces a more dynamic learning environment than a typical slide show , resulting in a more effective learning experience. The end result is that the viewer will have learned about the basics of spacecraft charging. This presentation is available to the public through our website, www.dplscience.com, free of charge. Viewers are encouraged to pass this presentation to colleagues within their own work environment. This paper describes the content of the multimedia presentation.

Lin, E.↗
DOE OSTI2018

MERS-CoV and H5N1 influenza virus antagonize antigen presentation by altering the epigenetic landscape

Convergent evolution dictates that diverse groups of viruses will target both similar and distinct host pathways in order to manipulate the immune response and improve infection. In this study, we sought to leverage this uneven viral antagonism to identify critical host factors that govern disease outcome. Utilizing a systems based approach, we examined differential regulation of IFNγ dependent genes following infection with highly pathogenic viruses including influenza (H5N1-VN1203, H1N1-CA04) and coronaviruses (SARS-CoV, MERS-CoV). Categorizing by function, we observed down regulation of genes associated with antigen presentation following both H5N1-VN1203 and MERS-CoV infection. Further examination revealed global down regulation of antigen presentation genes and was confirmed by proteomics for both H5N1-VN1203 and MERS-CoV infection. Importantly, epigenetic analysis suggested that DNA methylation rather than histone modification plays a crucial role in MERS-CoV mediated antagonism of antigen presentation genes; in contrast, H5N1-VN1203 likely utilizes a combination of epigenetic mechanisms to target antigen presentation. Altogether, the results indicate a common approach utilized by H5N1-VN1203 and MERS-CoV to modulate antigen presentation and the host adaptive immune response.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2018

Streptococcus salivarius-mediated CD8+ T cell stimulation required antigen presentation by macrophages in oral squamous cell carcinoma

It has been shown that the peripheral blood mononuclear cells (PBMCs) from oral squamous cell carcinoma (OSCC) patients presented cytotoxic CD8 T cell response against Streptococcus salivarius (S. salivarius), of which the frequency was positively associated with recurrence-free survival in OSCC patients. To identify the conditions required for regulating S. salivarius-specific CD8 T cell-mediated cytotoxicity, we selectively depleted individual components of the PBMCs, and observed that the depletion of monocytes/macrophages, but not other immune cell subsets, significantly downregulated the S. salivarius-specific CD8 T cell cytotoxicity. Monocyte/macrophage alone was sufficient to reconstitute optimal granzyme B expression from S. salivarius-specific CD8 T cells. Also, both the memory and the naive CD8 T cells reacted to S. salivarius-stimulation, with the memory CD8 T cells presenting significantly higher S. salivarius-reactivity. Using M1- and M2-polarized macrophages from circulating monocytes, we found that M1-polarized macrophages, with significantly higher IL-12 expression and significantly lower IL-10 and MHC class II molecule expression, was more effective at promoting granzyme B responses in CD8 T cells, and required CD80/CD86 costimulating molecules for optimal responses. Interestingly, the tumor-associated macrophages (TAMs) from resected tumors presented characteristics of M2-polarized macrophages with high MHC class II expression and low IL-12 secretion. The frequency of tumor-infiltrating S. salivarius-specific cytotoxic CD8 T cell was inversely correlated with the level of IL-10 secretion and the MHC class II molecule expression in autologous TAMs. Together, we demonstrated that monocyte/macrophages presented essential antigen-presentation and costimulatory roles in CD8 T cell-mediated S. salivarius-specific granzyme B responses, and the polarization of macrophages could influence the potency of CD8 T cell responses.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2025

Review of Presentation by Carter Wolf

The presentation was informative on the different techniques used to study the electronic dynamics of materials on the femtosecond scale, such as ARPES and TR ARPES. The presentation also discussed in depth code analysis, and the procedure used to remove noise from noisy data via machine learning procedures. The presentation first focused on an overview of the ARPES technique, and how TR-ARPES differs from it. The presentation then explored computational techniques used for fitting ARPES and TR-ARPES data, using the pyARPES framework. After that, the presentation discussed machine learning approaches for denoising noisy data such as Noise2Noise and Noise2Self. The main issue of denoising existing ARPES data and the necessity of machine learning approaches due to the lack of clean ARPES data were very clearly articulated as a major part of the project. The implementation, training and refinement and optimization were clearly detailed, along with a full documentation of attempts that worked and attempts that did not, thus thoroughly and clearly showing the research process. Experimental techniques regarding ARPES were also briefly documented.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Tailored design of protein nanoparticle scaffolds for multivalent presentation of viral glycoprotein antigens

Multivalent presentation of viral glycoproteins can substantially increase the elicitation of antigen-specific antibodies. To enable a new generation of anti-viral vaccines, we designed self-assembling protein nanoparticles with geometries tailored to present the ectodomains of influenza, HIV, and RSV viral glycoprotein trimers. We first de novo designed trimers tailored for antigen fusion, featuring N-terminal helices positioned to match the C termini of the viral glycoproteins. Trimers that experimentally adopted their designed configurations were incorporated as components of tetrahedral, octahedral, and icosahedral nanoparticles, which were characterized by cryo-electron microscopy and assessed for their ability to present viral glycoproteins. Electron microscopy and antibody binding experiments demonstrated that the designed nanoparticles presented antigenically intact prefusion HIV-1 Env, influenza hemagglutinin, and RSV F trimers in the predicted geometries. This work demonstrates that antigen-displaying protein nanoparticles can be designed from scratch, and provides a systematic way to investigate the influence of antigen presentation geometry on the immune response to vaccination.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1984

The USL NASA PC R and D interactive presentation development system

The Interactive Presentation Development System (IPFS) is a highly interactive system for creating, editing, and displaying video presentation sequences, e.g., for developing and presenting displays of instructional material similiar to overhead transparency or slide presentations. However, since this system is PC-based, users (instructors) can step through sequences forward or backward, focusing attention to areas of the display with special cursor pointers. Additionally, screen displays may be dynamically modified during the presentation to show assignments or to answer questions, much like a traditional blackboard. This system is now implemented at the University of Southwestern Louisiana for use within the piloting phases of the NASA contract work.

Dominick, Wayne D.↗
NASA NTRS1988

Presentation planning using an integrated knowledge base

A description is given of user interface research aimed at bringing together multiple input and output modes in a way that handles mixed mode input (commands, menus, forms, natural language), interacts with a diverse collection of underlying software utilities in a uniform way, and presents the results through a combination of output modes including natural language text, maps, charts and graphs. The system, Integrated Interfaces, derives much of its ability to interact uniformly with the user and the underlying services and to build its presentations, from the information present in a central knowledge base. This knowledge base integrates models of the application domain (Navy ships in the Pacific region, in the current demonstration version); the structure of visual displays and their graphical features; the underlying services (data bases and expert systems); and interface functions. The emphasis is on a presentation planner that uses the knowledge base to produce multi-modal output. There has been a flurry of recent work in user interface management systems. (Several recent examples are listed in the references). Existing work is characterized by an attempt to relieve the software designer of the burden of handcrafting an interface for each application. The work has generally focused on intelligently handling input. This paper deals with the other end of the pipeline - presentations.

Arens, Yigal↗
NASA NTRS1994

From computer images to video presentation: Enhancing technology transfer

With NASA placing increased emphasis on transferring technology to outside industry, NASA researchers need to evaluate many aspects of their efforts in this regard. Often it may seem like too much self-promotion to many researchers. However, industry's use of video presentations in sales, advertising, public relations and training should be considered. Today, the most typical presentation at NASA is through the use of vu-graphs (overhead transparencies) which can be effective for text or static presentations. For full blown color and sound presentations, however, the best method is videotape. In fact, it is frequently more convenient due to its portability and the availability of viewing equipment. This talk describes techniques for creating a video presentation through the use of a combined researcher and video professional team.

Beam, Sherilee F.↗
NASA NTRS1998

The Origin and Time Dependence of the Amount and Composition of Non-Constituent Gases Present in Crystal Growth Systems

Presence of different, non-constituent gases may be a critical factor in crystal growth systems. In Physical Vapor Transport processes the cras(es) can be used intentionally (to prevent excessively high, unstable growth conditions), or can evolve unintentionally during the course of the process (which may lead to undesired reduction in the -rowth rate). In melt growth, particularly under low gravity conditions (reduced hydrostatic pressure) the gas present in the system may contribute to formation of voids in the growing crystals and even to a separation of the crystal and the liquid phase [1]. On the other hand, some amount of gas may facilitate 'contactless' crystal growth particularly under reduced gravity conditions [2 - 6]. Different non-constituent gases may be present in growth ampoules, and their amount and composition may change during the crystallization process. Some gases can appear even in empty ampoules sealed originally under high vacuum: they may diffuse in from the outside, and/or desorb from the ampoule walls. Residual gases can also be generated by the source materials: even very high purity commercial elements and compounds may contain trace amounts of impurities, particularly oxides. The oxides may have low volatilities themselves but their reaction with other species, particularly carbon and hydrogen, may produce volatile compounds like water or carbon oxides. The non-constituent gases, either added initially to the system or evolved during the material processing, may diffuse out of the ampoule during the course of the experiment. Gases present outside (e.g. as a protective atmosphere or thermal conductor) may diffuse into the ampoule. In either case the growth conditions and the quality of the crystals may be affected. The problem is of a particular importance in sealed systems where the amount of the gases cannot be directly controlled. Therefore a reasonable knowledge and understanding of the origin, composition, magnitude, and change with time of gases present in sealed ampoules may be important for a meaningful control and interpretation of crystal growth processes. This problem is of a particular importance for processing of electronic materials in space because (i) safety considerations require using sealed systems only, and (ii) high cost of crystal growth experiments in microgravity calls for a throughout, accurate description of the processing conditions necessary for a meaningful, efficient, and conclusive interpretation of the space results. In this paper we present the results of our extensive studies on gases in closed crystal growth systems which include: (a) Degassing properties of fused silica; (b) Generation of inert gases by source materials (CdTe, ZnTe, CdZnTe, ZnSe, PbTe, PbSe, PbSeTe); (c) Diffusive cas losses from silica glass ampoules.

Palosz, Witold↗