SEARCH · Engineering Papers

Results for “community structure”

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.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 919 records · Page 51

All sources NASA NTRS DOE OSTI

DOE OSTI2023

TEAMER: Experimental performance characterization of a shrouded axial-flow turbine

Sitkana has developed a shrouded hydrokinetic turbine with a modular, low-cost design that can be scaled to meet the needs of remote communities. With technical support from the University of Washington, Sitkana sought to experimentally characterize the mechanical power and structural loads of various 1:3.3 scale rotor geometries. In all, 11 different rotor geometries were characterized with variations in height-to-diameter ratio, blade number, and blade type (foiled versus flat). All tests were conducted in Reynolds-independent flow conditions in the Alice C. Tyler Flume at the University of Washington. Results allow Sitkana to (1) refine the optimal rotor geometry, (2) validate numerical models, and (3) predict power output for a full-scale system. This project is part of the TEAMER RFTS 8 (request for technical support) program.

16 TIDAL AND WAVE POWER↗

DOE OSTI2022

Capability Needs for Irradiated and Radioactive Materials Research (Ad hoc Committee Summary Report)

It is essential for the U.S. nuclear energy community to have access to world-leading equipment suitable for conducting research on both nuclear fuels and structural materials, including neutron irradiated–and therefore activated–materials. To address future research infrastructure requirements to support the DOE-NE mission, the Office of Reactor Fleet and Advanced Reactor Deployment established an ad hoc committee to gather information on potential capability gaps for radioactive materials and radiation effects research. This document summarizes the discussions of the committee addressing the high-level challenges in irradiated and radioactive materials research and the capabilities needed to address these challenges. After considering the various needs, the committee agreed on the four top-level targets and priority capability gaps.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

DOE OSTI2024

Fueling Seniors: Meal Subsidy through Co-Generation

Formed in 1971, The Towers is an affordable HUD 202, 328-unit, living community with supportive services for extremely low, low and moderately low-income seniors. The average resident age is 79 and the average annual income is $\$$18,900. Approximately 70% of our residents receive assistance with their activities of daily living (e.g. hands-on bathing, feeding, dressing and toileting). We offer such services in a unique person-centered way through a wraparound support services model not always available in smaller low-income housing sites with assisted living (e.g. onsite service coordinators, engagement programs specific to the needs of our current and changing resident population and onsite 24-hour security who act as first response staff). The Towers serves the City of New Haven and surrounding areas by providing community-based senior care and support services that are affordable for individuals with limited resources. Our unique cost structure enables hundreds of seniors to avoid premature placement into nursing homes or other institutional care settings, even though they lack personal financial resources. This enables us to proactively keep our residents independent and healthy for as long as possible.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

NASA NTRS1981

municipal recreation center is heated and cooled by solar energy

Major fraction of energy requirements for community building is ksupplied by Sun. The 238 flat plate solar collectors are roof mounted on single story structure enclosing gymnasium, locker area, and health care clinic; heat exchanger transfers collected energy to 6,000 gallon storage tank. Final report chronicles project from inception to completion, documenting performance, costs, operating modes, and data acquisition system. Appendix contains manufacturers' product literature and engineering drawings.

Source record↗

NASA NTRS1982

Development status of the PDC-1 Parabolic Dish Concentrator

The status of development of the 12 m diameter parabolic dish concentrator which is planned for use with the Small Community Solar Thermal Power System. The PDC-1 unit features the use of plastic reflector film bonded to structural plastic gores supported by front-bracing steel ribs. An elevation-over-azimuth mount arrangement is employed, with a conventional wheel-and-track arrangement; outboard trunnions permit the dish to be stored in the face down position, with the added advantage of easy access to the power conversion assembly. The control system is comprised of a central computer (LSI 1123), a manual control panel, a concentrator control unit, two motor controllers, a Sun sensor, and two angular position resolvers. The system is designed for the simultaneous control of several concentrators. The optical testing of reflective panels is described.

Thostesen, T.↗

NASA NTRS1983

The workload book: Assessment of operator workload to engineering systems

The structure and initial work performed toward the creation of a handbook for workload analysis directed at the operational community of engineers and human factors psychologists are described. The goal, when complete, will be to make accessible to such individuals the results of theoretically-based research that are of practical interest and utility in the analysis and prediction of operator workload in advanced and existing systems. In addition, the results of laboratory study focused on the development of a subjective rating technique for workload that is based on psychophysical scaling techniques are described.

Gopher, D.↗

NASA NTRS1992

Microgravity science and applications program tasks, 1991 revision

Presented here is a compilation of the active research tasks for FY 1991 sponsored by the Microgravity Science and Applications Division of the NASA Office of Space Science and Applications. The purpose is to provide an overview of the program scope for managers and scientists in industry, university, and government communities. Included is an introductory description of the program, the strategy and overall goal, identification of the organizational structures and the people involved, and a description of each. The tasks are grouped into several categories: electronic materials; solidification of metals, alloys, and composites; fluids, interfaces, and transport; biotechnology; combustion science; glasses and ceramics; experimental technology, instrumentation, and facilities; and Physical and Chemistry Experiments (PACE). The tasks cover both the ground based and flight programs.

Source record↗

NASA NTRS1993

Mutual Inductance Problem for a System Consisting of a Current Sheet and a Thin Metal Plate

Rapid inspection of aircraft structures for flaws is of vital importance to the commercial and defense aircraft industry. In particular, inspecting thin aluminum structures for flaws is the focus of a large scale R&D effort in the nondestructive evaluation (NDE) community. Traditional eddy current methods used today are effective, but require long inspection times. New electromagnetic techniques which monitor the normal component of the magnetic field above a sample due to a sheet of current as the excitation, seem to be promising. This paper is an attempt to understand and analyze the magnetic field distribution due to a current sheet above an aluminum test sample. A simple theoretical model, coupled with a two dimensional finite element model (FEM) and experimental data will be presented in the next few sections. A current sheet above a conducting sample generates eddy currents in the material, while a sensor above the current sheet or in between the two plates monitors the normal component of the magnetic field. A rivet or a surface flaw near a rivet in an aircraft aluminum skin will disturb the magnetic field, which is imaged by the sensor. Initial results showed a strong dependence of the flaw induced normal magnetic field strength on the thickness and conductivity of the current-sheet that could not be accounted for by skin depth attenuation alone. It was believed that the eddy current imaging method explained the dependence of the thickness and conductivity of the flaw induced normal magnetic field. Further investigation, suggested the complexity associated with the mutual inductance of the system needed to be studied. The next section gives an analytical model to better understand the phenomenon.

Fulton, J. P.↗

NASA NTRS2005

Development of a Modeling Framework to Support Control Investigations of Sailcraft Missions A First Cut: ABLE Sailcraft Dynamics Model

Solar Sailcraft, the stuff of dreams of the H.G. Wells generation, is now a rapidly maturing reality. The promise of unlimited propulsive power by harnessing stellar radiation is close to realization. Currently, efforts are underway to build, prototype and test two configurations. These sails are designed to meet a 20m sail requirement, under guidance of the In-Space Propulsion (ISP) technology program office at MSFC. While these sails will not fly , they are the first steps in improving our understanding of the processes and phenomena at work. As part of the New Millennium Program (NMP) the ST9 technology validation mission hopes to launch and fly a solar sail by 2010 or sooner. Though the Solar Sail community has been studying and validating various concepts over two decades, it was not until recent breakthroughs in structural and material technology, has made possible to build sails that could be launched. With real sails that can be tested (albeit under earth conditions), the real task of engineering a viable spacecraft has finally commenced. Since it is not possible to accurately or practically recreate the actual operating conditions of the sailcraft (zero-G, vacuum and extremely low temperatures), much of the work has focused on developing accurate models that can be used to predict behavior in space, and for sails that are 6-10 times the size of currently existing sails. Since these models can be validated only with real test data under "earth" conditions, the process of modeling and the identification of uncertainty due to model assumptions and scope need to be closely considered. Sailcraft models that exist currently, are primarily focused on detailed physical representations at the component level, these are intended to support prototyping efforts. System level models that cut across different sail configurations and control concepts while maintaining a consistent approach are non-existent. Much effort has been focused on the areas of thrust performance, solar radiation prediction, and sail membrane behavior vis-a-vis their reflective geometry, such as wrinkling/folding/furling as it pertains to thrust prediction. A parallel effort has been conducted on developing usable models for developing attitude control systems (ACS), for different sail configurations in different regimes. There has been very little by way of a system wide exploration of the impact of the various control schemes, thrust prediction models for different sail configurations being considered.

Sarathy, Sriprakash↗

NASA NTRS2010

Risk as a Driver for Innovation

The Space Life Sciences directorate (SLSD) and Human Research Program (HRP) at NASA Johnson Space Center has implemented a system for managing human systems risks. These risks are defined as the health and performance risks posed to crew during and after spaceflight. Identification and evaluation of these risks has led to the identification of gaps in knowledge about the risks as well as gaps in technology needed to mitigate them. Traditional routes of closing technology gaps have, in some cases, proven to be too slow when a solution was required quickly. Therefore, certain gaps were used to drive the development of "challenges" for the scientific community. Partnering with open innovation service providers such as InnoCentive and Yet2.com, SLSD and HRP have decreased the amount of time from identification of a need to the evaluation of a solution. Although not all proposed solutions will result in a risk mitigation strategy or tool, the process has allowed faster evaluation of proposed solutions providing the researcher the ability to move to another possible solution if the first does not sufficiently address the problem. Moreover, this process engages the community outside of NASA and broadens the population from which to draw solutions. In the traditional grant funding structure, only those in the specific field will apply for the grant. However, using open innovation, solutions can come from individuals in many different fields. This can expand the general view of a field (way of thinking within a field) and the application of solutions form new fields while providing a pathway for the acquisition of novel solutions or refinements of current mitigations. Identification of the human systems risks has helped drive the development and evaluation of innovative solutions as well as engaging a broader scientific audience in working with NASA.

Davis, Jeff↗

NASA NTRS2015

Variability in the Propagation Phase of CFD-Based Noise Prediction: Summary of Results From Category 8 of the BANC-III Workshop

The usage of Computational Fluid Dynamics (CFD) in noise prediction typically has been a two part process: accurately predicting the flow conditions in the near-field and then propagating the noise from the near-field to the observer. Due to the increase in computing power and the cost benefit when weighed against wind tunnel testing, the usage of CFD to estimate the local flow field of complex geometrical structures has become more routine. Recently, the Benchmark problems in Airframe Noise Computation (BANC) workshops have provided a community focus on accurately simulating the local flow field near the body with various CFD approaches. However, to date, little effort has been given into assessing the impact of the propagation phase of noise prediction. This paper includes results from the BANC-III workshop which explores variability in the propagation phase of CFD-based noise prediction. This includes two test cases: an analytical solution of a quadrupole source near a sphere and a computational solution around a nose landing gear. Agreement between three codes was very good for the analytic test case, but CFD-based noise predictions indicate that the propagation phase can introduce 3dB or more of variability in noise predictions.

Lopes, Leonard↗

DOE OSTI2020

Extending the Publish/Subscribe Abstraction for High-Performance I/O and Data Management at Extreme Scale

The Adaptable I/O System (ADIOS) represents the culmination of substantial investment in Scientific Data Management, and it has demonstrated success for several important extreme-scale science cases. However, looking towards the exascale and beyond, we see the development of yet more stringent data management requirements that require new abstractions. Therefore, there is an opportunity to attempt to connect the traditional realms of HPC I/O optimization with the Database / Data Management community. As such, in this paper we offer some specific examples from our ongoing work in managing data structures, services, and performance at the extreme scale for scientific computing. Using the publish/subscribe model afforded by ADIOS, we demonstrate a set of services that connect data format, metadata, queries, data reduction, and high-performance delivery. The resulting publish/subscribe framework facilitates connection to on-line workflow systems to enable the dynamic capabilities that will be required for exascale science.

96 KNOWLEDGE MANAGEMENT AND PRESERVATION↗

DOE OSTI2025

First-principles study of structural, elastic, electronic, transport properties, and dielectric breakdown of Cs 2 Te photocathode

The pursuit to operate photocathodes at high accelerating gradients to increase brightness of electron beams is gaining interests within the accelerator community, particularly for applications such as free electron lasers (FEL) and compact accelerators. Cesium telluride (Cs 2 Te) is a widely used photocathode material and it is presumed to offer resilience to higher gradients because of its wider band gap compared to other semiconductors. Despite its advantages, crucial material properties of Cs 2 Te remain largely unknown both in theory and experiments. In this study, we employ first-principles calculations to provide detailed structural, elastic, electronic and transport properties of Cs 2 Te. It is found that Cs 2 Te has an intrinsic mobility of 20 cm 2 /Vs for electrons and 2.0 cm 2 /Vs for holes at room temperature. The low mobility is primarily limited by the strong polar optical phonon scattering. Cs 2 Te also exhibits ultralow lattice thermal conductivity of 0.2 W/(m*K) at room temperature. Based on the energy gain/loss balance under external field and electron–phonon scattering, we predict that Cs 2 Te has a dielectric breakdown field in the range from ~ 60 to ~ 132 MV/m at room temperature dependent on the doping level of Cs 2 Te. Our results are crucial to advance the understanding of applicability of Cs 2 Te photocathodes for high-gradient operation.

36 MATERIALS SCIENCE↗

NASA NTRS2007

Science and the Constellation Systems Program Office

An underlying tension has existed throughout the history of NASA between the human spaceflight programs and the external scientific constituencies of the robotic exploration programs. The large human space projects have been perceived as squandering resources that might otherwise be utilized for scientific discoveries. In particular, the history of the relationship of science to the International Space Station Program has not been a happy one. The leadership of the Constellation Program Office, created in NASA in October, 2005, asked me to serve on the Program Manager s staff as a liaison to the science community. Through the creation of my position, the Program Manager wanted to communicate and elucidate decisions inside the program to the scientific community and, conversely, ensure that the community had a voice at the highest levels within the program. Almost all of my technical contributions at NASA, dating back to the Apollo Program, has been within the auspices of what is now known as the Science Mission Directorate. However, working at the Johnson Space Center, where human spaceflight is the principal activity, has given me a good deal of incidental contact and some more direct exposure through management positions to the structures and culture of human spaceflight programs. I entered the Constellation family somewhat naive but not uninformed. In addition to my background in NASA science, I have also written extensively over the past 25 years on the topic of human exploration of the Moon and Mars. (See, for example, Mendell, 1985). I have found that my scientific colleagues generally have little understanding of the structure and processes of a NASA program office; and many of them do not recognize the name, Constellation. In many respects, the international ILEWG community is better informed. Nevertheless, some NASA decision processes on the role of science, particularly with respect to the formulation of a lunar surface architecture, are not well known, even in ILEWG. At the recent annual Lunar and Planetary Science Conference, I reviewed the evolution of the program as a function of Agency leadership and the constraints put on NASA by the President in his 2004 announcement. I plan to continue my long-time ILEWG tradition of reporting a personal view of the state of development of human exploration of the solar system, this time coming from within the program office tasked to implement the vision for the United States. The current NASA implementation of the Vision for Space Exploration is consistent with certain classical scenarios that have been discussed extensively in the literature. I will discuss the role of science within the Vision, both from official policy and from a de facto interaction. While science goals are not officially driving the implementation of the Vision, the tools of scientific exploration are integral to defining the extraterrestrial design environments. In this respect the sharing of results from international missions to the Moon can make significant contributions to the success of the future human activities.

Mendell, Wendell↗

NASA NTRS2017

WCRP Task Team for the Intercomparison of Reanalyses (TIRA): Motivation and Progress

Reanalyses have proven to be an important resource for weather and climate related research, as well as societal applications at large. Several centers have emerged to produce new atmospheric reanalyses in various forms every few years. In addition, land and ocean communities are producing disciplinary uncoupled reanalyses. Current research and development in reanalysis is directed at (1) extending the length of reanalyzed period and (2) use of coupled Earth system models for climate reanalysis. While WCRPs involvement in the reanalyses communities through its Data Advisory Council (WDAC) has been substantial, for example in organizing international conferences on reanalyses, a central team of reanalyses expertise is not in place in the WCRP structure. The differences among reanalyses and their inherent uncertainties are some of the most important questions for both users and developers of reanalyses. Therefore, a collaborative effort to systematically assess and intercompare reanalyses would be a logical progression that fills the needs of the community and contributes to the WCRP mission. The primary charge to the TIRA is to develop a reanalysis intercomparison project plan that will attain the following objectives.1)To foster understanding and estimation of uncertainties in reanalysis data by intercomparison and other means 2)To communicate new developments and best practices among the reanalyses producing centers 3)To enhance the understanding of data and assimilation issues and their impact on uncertainties, leading to improved reanalyses for climate assessment 4)To communicate the strengths and weaknesses of reanalyses, their fitness for purpose, and best practices in the use of reanalysis datasets by the scientific community. This presentation outlines the need for a task team on reanalyses, their intercomparison, the objectives of the team and progress thus far.

WDA↗

DOE OSTI2024

Signatures of cysteine oxidation on muscle structural and contractile proteins are associated with physical performance and muscle function in older adults: Study of Muscle, Mobility and Aging (SOMMA)

Oxidative stress is considered a contributor to declining muscle function and mobility during aging; however, the underlying molecular mechanisms remain poorly described. We hypothesized that greater levels of cysteine (Cys) oxidation on muscle proteins are associated with decreased measures of mobility. Herein, we applied a novel redox proteomics approach to measure reversible protein Cys oxidation in vastus lateralis muscle biopsies collected from 56 subjects in the Study of Muscle, Mobility and Aging (SOMMA), a community-based cohort study of individuals aged 70 years and older. We tested whether levels of Cys oxidation on key muscle proteins involved in muscle structure and contraction were associated with muscle function (leg power and strength), walking speed, and fitness (VO 2 peak on cardiopulmonary exercise testing) using linear regression models adjusted for age, sex, and body weight. Higher oxidation levels of select nebulin Cys sites were associated with lower VO 2 peak, while greater oxidation of myomesin-1, myomesin-2, and nebulin Cys sites was associated with slower walking speed. Higher oxidation of Cys sites in key proteins such as myomesin-2, alpha-actinin-2, and skeletal muscle alpha-actin were associated with lower leg power and strength. We also observed an unexpected correlation (R = 0.48) between a higher oxidation level of eight Cys sites in alpha-actinin-3 and stronger leg power. Despite this observation, the results generally support the hypothesis that Cys oxidation of muscle proteins impairs muscle power and strength, walking speed, and cardiopulmonary fitness with aging.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2026

Atomistic Simulation of Glasses and Amorphous Materials: Challenges and Opportunities for the Next Decade

Atomistic simulations have become indispensable tools for understanding glass structure, dynamics, and properties, yet persistent challenges limit their predictive power. This perspective examines three interconnected issues, namely glass formation procedures, interatomic potential development, and machine learning applications, which emerged from the 5th International Workshop on Challenges of Atomistic Simulations of Glasses and Amorphous Materials. We identify convergent community priorities for (i) standardized validation protocols, (ii) curated benchmark datasets with complete metadata, and (iii) open repositories for glasses. A systematic was forward is provided by a hierarchical validation framework for assessing the structural fidelity, property prediction, and behavioral realism of simulation techniques. Looking ahead, transformative advances are promised by the fusion of classical techniques with machine learning based approaches, for instance, by integrating swap Monte Carlo with machine-learning (ML) potentials, leveraging foundation models through transfer learning, and finetuning ML potentials with experimental data. Progress depends on the community committing to validated models, reproducible protocols, and sustained data sharing.

Krishnan, N. M. Anoop↗

DOE OSTI2023

Alkaline-SDS cell lysis of microbes with acetone protein precipitation for proteomic sample preparation in 96-well plate format

Plate-based proteomic sample preparation offers a solution to the large sample throughput demands in the biotechnology field where hundreds or thousands of engineered microbes are constructed for testing is routine. Meanwhile, sample preparation methods that work efficiently on broader microbial groups are desirable for new applications of proteomics in other fields, such as microbial communities. Here, we detail a step-by-step protocol that consists of cell lysis in an alkaline chemical buffer (NaOH/SDS) followed by protein precipitation with high-ionic strength acetone in 96-well format. The protocol works for a broad range of microbes ( e . g ., Gram-negative bacteria, Gram-positive bacteria, non-filamentous fungi) and the resulting proteins are ready for tryptic digestion for bottom-up quantitative proteomic analysis without the need for desalting column cleanup. The yield of protein using this protocol increases linearly with respect to the amount of starting biomass from 0.5–2.0 OD*mL of cells. By using a bench-top automated liquid dispenser, a cost-effective and environmentally-friendly option to eliminating pipette tips and reducing reagent waste, the protocol takes approximately 30 minutes to extract protein from 96 samples. Tests on mock mixtures showed expected results that the biomass composition structure is in close agreement with the experimental design. Lastly, we applied the protocol for the composition analysis of a synthetic community of environmental isolates grown on two different media. This protocol has been developed to facilitate rapid, low-variance sample preparation of hundreds of samples and allow flexibility for future protocol development.

59 BASIC BIOLOGICAL SCIENCES↗