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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 1,369 records · Page 76
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Reducing ultrafine particle emissions using air injection in wood-burning cookstoves

In order to address the health risks and climate impacts associated with pollution from cooking on biomass fires, researchers have focused on designing new cookstoves that improve cooking performance and reduce harmful emissions, specifically particulate matter (PM). One method for improving cooking performance and reducing emissions is using air injection to increase turbulence of unburned gases in the combustion zone. Although air injection reduces total PM mass emissions, the effect on PM size-distribution and number concentration has not been thoroughly investigated. Using two new wood-burning cookstove designs from Lawrence Berkeley National Laboratory, this research explores the effect of air injection on cooking performance, PM and gaseous emissions, and PM size distribution and number concentration. Both cookstoves were created using the Berkeley-Darfur Stove as the base platform to isolate the effects of air injection. The thermal performance, gaseous emissions, PM mass emissions, and particle concentrations (ranging from 5 nm to 10 μm in diameter) of the cookstoves were measured during multiple high-power cooking tests. Finally, the results indicate that air injection improves cookstove performance and reduces total PM mass but increases total ultrafine (less than 100 nm in diameter) PM concentration over the course of high-power cooking.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Effect of Electrolyte on High Sulfur Loading Li-S Batteries

Practical lithium-sulfur batteries require high sulfur electrode loading and lean electrolyte designs, which entail more research efforts on the two cell-design parameters - sulfur loading and electrolyte/sulfur loading ratio (E/S). In this work, a systematic investigation is performed to understand the impact of these two variables over key Li-S cell performance parameters. It is demonstrated that Li-S cells’ power performance strongly depends on the E/S ratio, while both E/S ratio and sulfur loading significantly influence the cycle life of Li-S cells. Low E/S ratio and high sulfur loading both give rise to fast lithium anode corrosion, which induces fast capacity fade and Coulombic efficiency decay. Pre-passivation of the lithium anode with an ionic conductor Li 3 PO 4 protection layer only improves the Coulombic efficiency retention at sulfur loading levels much lower than the practical threshold. Meanwhile, increasing the concentration of LiNO 3 additive in the electrolyte is found effective in sustaining the cycling capacity and the Coulombic efficiency over a reasonable usage window (~200 cycles). In conclusion, the role of LiNO 3 is the protection of lithium anode during cycling.

25 ENERGY STORAGE↗
DOE OSTI2015

Diffusion of Designerly Finite Element Analysis

To address a variety of difficulties surrounding the use of finite element analysis (FEA) in product development at Sandia, this research explored a 'designerly' insertion of FEA into the design-build-test product development cycle. Designerly FEA is characterized by the use of simplified FEA models, designer-friendly FEA software, an FEA analyst embedded in the product design team, relative comparisons of design options, and a deliberate leveraging of routine prototype testing to collect model validation data. Two case study projects were used to explore the impact of this approach on the product development teams' thinking and perceptions of FEA. The case study data was collected using mixed methods and analyzed using a theory-building approach. The results were synthesized into a framework describing how the use of FEA to build confidence in a product design is related to the process by which product development teams gain or lose confidence in FEA itself. The implications may extend to other organizations that desire to increase the impact of simulation technologies in their product development process.

97 MATHEMATICS AND COMPUTING↗
NASA NTRS1989

A compendium of controlled diffusion blades generated by an automated inverse design procedure

A set of sample cases was produced to test an automated design procedure developed at the NASA Lewis Research Center for the design of controlled diffusion blades. The range of application of the automated design procedure is documented. The results presented include characteristic compressor and turbine blade sections produced with the automated design code as well as various other airfoils produced with the base design method prior to the incorporation of the automated procedure.

Sanz, Jose M.↗
NASA NTRS1998

Perceptions of Engineers Regarding Successful Engineering Team Design

The perceptions of engineers and scientists at NASA Langley Research Center toward engineering design teams were evaluated. A sample of 49 engineers and scientists rated 60 team behaviors in terms of their relative importance for team success. They also completed a profile of their own perceptions of their strengths and weaknesses as team members. Behaviors related to team success are discussed in terms of those involving the organizational culture and commitment to the team and those dealing with internal team dynamics. The latter behaviors focused on team issues occurring during the early stages of a team's existence. They included the level and extent of debate and discussion regarding methods for completing the team task and the efficient use of team time to explore and discuss methodologies critical to the problem. The discussion includes a comparison of engineering teams with the prototypical business team portrayed in the literature.

Nowaczyk, Ronald H.↗
NASA NTRS2003

Physiology, medicine, long-duration space flight and the NSBRI

The hazards of long-duration space flight are real and unacceptable. In order for humans to participate effectively in long-duration orbital missions or continue the exploration of space, we must first secure the health of the astronaut and the success of such missions by assessing in detail the biomedical risks of space flight and developing countermeasures to these hazards. Acquiring the understanding necessary for building a sound foundation for countermeasure development requires an integrated approach to research in physiology and medicine and a level of cooperative action uncommon in the biomedical sciences. The research program of the National Space Biomedical Research Institute (NSBRI) was designed to accomplish just such an integrated research goal, ameliorating or eliminating the biomedical risks of long-duration space flight and enabling safe and productive exploration of space. The fruits of these labors are not limited to the space program. We can also use the gained understanding of the effects and mechanisms of the physiological changes engendered in space and the applied preventive and rehabilitative methods developed to combat these changes to the benefit of those on Earth who are facing similar physiological and psychological difficulties. This paper will discuss the innovative approach the NSBRI has taken to integrated research management and will present some of the successes of this approach. c2003 International Astronautical Federation. Published by Elsevier Science Ltd. All rights reserved.

NASA Discipline General Space Life Sciences↗
NASA NTRS2000

Critical Questions for Space Human Factors

Traditional human factors contributions to NASA's crewed space programs have been rooted in the classic approaches to quantifying human physical and cognitive capabilities and limitations in the environment of interest, and producing recommendations and standards for the selection or design of mission equipment. Crews then evaluate the interfaces, displays, or equipment, and with the assistance of human factors experts, improvements are made as funds, time, control documentation, and weight allow. We have come a long way from the early spaceflight days, where men with the ' right stuff were the solution to operating whatever equipment was given to them. The large and diverse Shuttle astronaut corps has impacted mission designs to accommodate a wide range of human capabilities and preferences. Yet with existing long duration experience, we have seen the need to address a different set of dynamics when designing for optimal crew performance: critical equipment and mission situations degrade, and human function changes with mission environment, situation, and duration. Strategies for quantifying the critical nature of human factors requirements are being worked by NASA. Any exploration-class mission will place new responsibilities on mission designers to provide the crew with the information and resources to accomplish the mission. The current duties of a Mission Control Center to monitor system status, detect degradation or malfunction, and provide a proven solution, will need to be incorporated into on-board systems to allow the crew autonomous decision-making. The current option to resupply and replace mission systems and resources, including both vehicle equipment and human operators, will be removed, so considerations of maintenance, onboard training, and proficiency assessment are critical to providing a self-sufficient crew. As we 'move in' to the International Space Station, there are tremendous opportunities to investigate our ability to design for autonomous crews. Yet prioritizing the research that can and should be done by NASA will be based on the critical nature of the issues, and the impact of the individual research questions on mission design. The risks to crew health and safety associated with answering critical human factors issues must be properly included and communicated in order to support the Agency's decisions regarding future space programs.

Woolford, Barbara↗
NASA NTRS2012

Subscale Flight Testing for Aircraft Loss of Control: Accomplishments and Future Directions

Subscale flight-testing provides a means to validate both dynamic models and mitigation technologies in the high-risk flight conditions associated with aircraft loss of control. The Airborne Subscale Transport Aircraft Research (AirSTAR) facility was designed to be a flexible and efficient research facility to address this type of flight-testing. Over the last several years (2009-2011) it has been used to perform 58 research flights with an unmanned, remotely-piloted, dynamically-scaled airplane. This paper will present an overview of the facility and its architecture and summarize the experimental data collected. All flights to date have been conducted within visual range of a safety observer. Current plans for the facility include expanding the test volume to altitudes and distances well beyond visual range. The architecture and instrumentation changes associated with this upgrade will also be presented.

Cox, David E.↗
NASA NTRS2014

Continued Water-Based Phase Change Material Heat Exchanger Development

In a cyclical heat load environment such as low Lunar orbit, a spacecraft's radiators are not sized to reject the full heat load requirement. Traditionally, a supplemental heat rejection device (SHReD) such as an evaporator or sublimator is used to act as a "topper" to meet the additional heat rejection demands. Utilizing a Phase Change Material (PCM) heat exchanger (HX) as a SHReD provides an attractive alternative to evaporators and sublimators as PCM HXs do not use a consumable, thereby leading to reduced launch mass and volume requirements. In continued pursuit of water PCM HX development two full‐scale, Orion sized water‐based PCM HX's were constructed by Mezzo Technologies. These HX's were designed by applying prior research and experimentation to the full scale design. Design options considered included bladder restraint and clamping mechanisms, bladder manufacturing, tube patterns, fill/drain methods, manifold dimensions, weight optimization, and midplate designs. Design and construction of these HX's led to successful testing of both PCM HX's.

Hansen, Scott↗
NASA NTRS2016

Design Requirements for Unmanned Rotorcraft Used in Low-Risk Concepts of Operation

This technical report presents the results of the second of two research studies on design and performance requirements supporting airworthiness certification of midrange unmanned aircraft systems (UAS) intended for commercial use. The two studies focused attention on UAS in the middle of the multidimensional spectrum of UAS; that is, UAS with attributes and capabilities exceeding the criteria to operate under Part 107 of the Federal Aviation Regulations (FARs), but without the design or operational capabilities to comply with the airworthiness standards for commercially-operated manned aircraft. The goal of the two studies was to help address the gap in airworthiness standards for some UAS that fall between the extremes.

Hayhurst, Kelly J.↗
NASA NTRS2017

Building a Practical Natural Laminar Flow Design Capability

A preliminary natural laminar flow (NLF) design method that has been developed and applied to supersonic and transonic wings with moderate-to-high leading-edge sweeps at flight Reynolds numbers is further extended and evaluated in this paper. The modular design approach uses a knowledge-based design module linked with different flow solvers and boundary layer stability analysis methods to provide a multifidelity capability for NLF analysis and design. An assessment of the effects of different options for stability analysis is included using pressures and geometry from an NLF wing designed for the Common Research Model (CRM). Several extensions to the design module are described, including multiple new approaches to design for controlling attachment line contamination and transition. Finally, a modification to the NLF design algorithm that allows independent control of Tollmien-Schlichting (TS) and cross flow (CF) modes is proposed. A preliminary evaluation of the TS-only option applied to the design of an NLF nacelle for the CRM is performed that includes the use of a low-fidelity stability analysis directly in the design module.

Campbell, Richard L.↗
DOE OSTI2022

The 2021 room-temperature superconductivity roadmap

Designing materials with advanced functionalities is the main focus of contemporary solid-state physics and chemistry. Research efforts worldwide are funneled into a few high-end goals, one of the oldest, and most fascinating of which is the search for an ambient temperature superconductor (A-SC). The reason is clear: superconductivity at ambient conditions implies being able to handle, measure and access a single, coherent, macroscopic quantum mechanical state without the limitations associated with cryogenics and pressurization. This would not only open exciting avenues for fundamental research, but also pave the road for a wide range of technological applications, affecting strategic areas such as energy conservation and climate change. In this roadmap we have collected contributions from many of the main actors working on superconductivity, and asked them to share their personal viewpoint on the field. The hope is that this article will serve not only as an instantaneous picture of the status of research, but also as a true roadmap defining the main long-term theoretical and experimental challenges that lie ahead. Interestingly, although the current research in superconductor design is dominated by conventional (phonon-mediated) superconductors, there seems to be a widespread consensus that achieving A-SC may require different pairing mechanisms.

"Toward hot superconductivity"↗
DOE OSTI2018

Flowzilla: A Methodology for Detecting Data Transfer Anomalies in Research Networks

© 2018 IEEE. Research networks are designed to support high volume scientific data transfers that span multiple network links. Like any other network, research networks experience anomalies. Anomalies are deviations from profiles of normality in a research network's traffic levels. Diagnosing anomalies is critical both for network operators and users (e.g., scientists). In this paper we present Flowzilla, a general framework for detecting and quantifying anomalies on scientific data transfers of arbitrary size. Flowzilla incorporates Random Forest Regression(RFR) for predicting the size of data transfers and utilizes an adaptive threshold mechanism for detecting outliers. Our results demonstrate that our framework achieves up to 92.5% detection accuracy. Furthermore, we are able to predict data transfer sizes up to 10 weeks after training with accuracy above 90%.

Giannakou, Anna↗
NASA NTRS1989

A large scale software system for simulation and design optimization of mechanical systems

The concept of an advanced integrated, networked simulation and design system is outlined. Such an advanced system can be developed utilizing existing codes without compromising the integrity and functionality of the system. An example has been used to demonstrate the applicability of the concept of the integrated system outlined here. The development of an integrated system can be done incrementally. Initial capabilities can be developed and implemented without having a detailed design of the global system. Only a conceptual global system must exist. For a fully integrated, user friendly design system, further research is needed in the areas of engineering data bases, distributed data bases, and advanced user interface design.

Dopker, Bernhard↗
NASA NTRS2012

Optimized Temporal Monitors for SystemC

SystemC is a modeling language built as an extension of C++. Its growing popularity and the increasing complexity of designs have motivated research efforts aimed at the verification of SystemC models using assertion-based verification (ABV), where the designer asserts properties that capture the design intent in a formal language such as PSL or SVA. The model then can be verified against the properties using runtime or formal verification techniques. In this paper we focus on automated generation of runtime monitors from temporal properties. Our focus is on minimizing runtime overhead, rather than monitor size or monitor-generation time. We identify four issues in monitor generation: state minimization, alphabet representation, alphabet minimization, and monitor encoding. We conduct extensive experimentation and identify a combination of settings that offers the best performance in terms of runtime overhead.

Tabakov, Deian↗
NASA NTRS1986

Design and development of a Space Station proximity operations research and development mockup

Proximity operations (Prox-Ops) on-orbit refers to all activities taking place within one km of the Space Station. Designing a Prox-Ops control station calls for a comprehensive systems approach which takes into account structural constraints, orbital dynamics including approach/departure flight paths, myriad human factors and other topics. This paper describes a reconfigurable full-scale mock-up of a Prox-Ops station constructed at Ames incorporating an array of windows (with dynamic star field, target vehicle(s), and head-up symbology), head-down perspective display of manned and unmanned vehicles, voice- actuated 'electronic checklist', computer-generated voice system, expert system (to help diagnose subsystem malfunctions), and other displays and controls. The facility is used for demonstrations of selected Prox-Ops approach scenarios, human factors research (work-load assessment, determining external vision envelope requirements, head-down and head-up symbology design, voice synthesis and recognition research, etc.) and development of engineering design guidelines for future module interiors.

Haines, Richard F.↗
DOE OSTI2023

Safeguards by Design Table Top Exercises Final Report (FY 2023)

This University Engagement project challenged engineering students at universities, that do not have bachelor’s degree programs in nuclear engineering but do have research reactors and some nuclear engineering coursework, to develop capacity in Safeguards by Design concepts through the application of Tabletop Exercises. This University Engagement project was part of the U. S. Department of Energy’s (DOE) National Nuclear Security Administration (NNSA), Office of Defense Nuclear Nonproliferation, Office of International Nuclear Safeguards, Next Generation Safeguards Initiative (NGSI), Human Capital Development (HCD): University Engagement Program. This program exposed university students with Mechanical Engineering majors and Nuclear Engineering minors to the concepts of international nuclear safeguards. In FY22, three teams at the University of Rhode Island and two teams at the University of Texas Austin participated in researching, designing, building, and testing projects to support international nuclear safeguards measurements or verification. The projects involved engaging in activities at the university’s research reactors. All the projects engaged students with prototyping a design and/or tool for application at the Universities’ reactor. However, for FY23, the direction of the HCD project had changed to implementing a Tabletop Exercise in Safeguards by Design (SBD). A Tabletop Exercise was not executed during FY23, but relationships with both Universities was maintained and how to integrate the exercise into the curriculum of both programs was determined.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2019

Enhancing Research Reactor Safeguards Through the Use of Mailbox Declarations

There are historic examples in several States of research reactors being misused to produce undeclared nuclear material. However, misuse of a State’s research reactor has typically only been discovered after further investigation into the State’s non-compliance related to other undeclared activities. Light water research reactors are typically designed with sample irradiation ports, where the introduction of fertile material can illicitly produce fissile material. Additionally, some light water reactors continue to be fueled by highly enriched uranium, which is a more significant safeguards concern by the International Atomic Energy Agency (IAEA). Heavy water and graphite reactors can be used for illicit plutonium production, which is of particular proliferation concern. Because research reactors are designed for flexible operations and small research reactors are less frequently inspected by the IAEA than other nuclear facilities (depending on power and fuel type, it could several years between inspections), the likelihood of timely detection by the IAEA of misuse of the research reactor is low. During a 2013 workshop on safeguarding research reactors, the United States, France, and the United Kingdom made recommendations to the IAEA on how safeguards could be strengthened for such facilities. One of the recommendations was to assess the use of “mailbox” declarations coupled with short notice random inspections or unannounced inspections by the IAEA at research reactors. An electronic mailbox declaration refers to the use of a secure information repository into which an operator submits operating reports. The near real time submittal of information enables the IAEA to better implement randomized short notice inspections. These mailboxes are not used for collecting and submitting State reports to the IAEA, but for collecting and transmitting operator data. The use of mailboxes, in conjunction with short notice random inspections, is in routine use for some other facility types. This paper assesses the potential for the practical application of mailbox declarations for various research reactor types and how the approach could be effectively used. Potential diversion scenarios are described and operator data records are discussed in connection to mailbox declarations, including discussion of how the data could indicate research reactor misuse.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗