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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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NASA NTRS2009

TOGA - A GNSS Reflections Instrument for Remote Sensing Using Beamforming

Remotely sensing the Earth's surface using GNSS signals as bi-static radar sources is one of the most challenging applications for radiometric instrument design. As part of NASA's Instrument Incubator Program, our group at JPL has built a prototype instrument, TOGA (Time-shifted, Orthometric, GNSS Array), to address a variety of GNSS science needs. Observing GNSS reflections is major focus of the design/development effort. The TOGA design features a steerable beam antenna array which can form a high-gain antenna pattern in multiple directions simultaneously. Multiple FPGAs provide flexible digital signal processing logic to process both GPS and Galileo reflections. A Linux OS based science processor serves as experiment scheduler and data post-processor. This paper outlines the TOGA design approach as well as preliminary results of reflection data collected from test flights over the Pacific ocean. This reflections data demonstrates observation of the GPS L1/L2C/L5 signals.

GPS↗

DOE OSTI2017

Unstated assumptions in alarm management - 202

Alarm management in the process industries has been an increasing area of activity since the first publications of EEMUA 191 in 1999 and ISA18.2 in 2008. Most major oil and chemical companies have adopted some or all of the metrics for alarm management presented in these documents. However, simply targeting for these metrics might not be the best course of action for a company. Many of the metrics involve assumptions or logic not explicitly stated in the guidelines, assumptions that might not be valid for a given console or plant. In other cases, metrics are the result of implied, rather than explicit, relationships between alarm guidelines. Again, the implied connection might not be true under certain circumstances. Understanding these unstated underpinnings of alarm management can facilitate the implementation of a useful and efficient alarm management program. This paper explores some of the key unstated assumptions in alarm management and how changes in those assumptions can alter both the interpretation of alarm metrics as well as what metrics are utilized. (authors)

47 OTHER INSTRUMENTATION↗

NASA NTRS1978

Implementation of an optimum profile guidance system on STOLAND

The implementation on the STOLAND airborne digital computer of an optimum profile guidance system for the augmentor wing jet STOL research aircraft is described. Major tasks were to implement the guidance and control logic to airborne computer software and to integrate the module with the existing STOLAND navigation, display, and autopilot routines. The optimum profile guidance system comprises an algorithm for synthesizing mimimum fuel trajectories for a wide range of starting positions in the terminal area and a control law for flying the aircraft automatically along the trajectory. The avionics software developed is described along with a FORTRAN program that was constructed to reflect the modular nature and algorthms implemented in the avionics software.

Flanagan, P. F.↗

NASA NTRS1992

In the soft-to-hard technical spectrum: Where is software engineering?

In the computer journals and tabloids, there have been a plethora of articles written about the software engineering field. But while advocates of the need for an engineering approach to software development, it is impressive how many authors have treated the subject of software engineering without adequately addressing the fundamentals of what engineering as a discipline consists of. A discussion is presented of the various related facets of this issue in a logical framework to advance the thesis that the software development process is necessarily an engineering process. The purpose is to examine more of the details of the issue of whether or not the design and development of software for digital computer processing systems should be both viewed and treated as a legitimate field of professional engineering. Also, the type of academic and professional level education programs that would be required to support a software engineering discipline is examined.

Leibfried, Theodore F.↗

NASA NTRS1998

Fuzzy Adaptive Control for Intelligent Autonomous Space Exploration Problems

The principal objective of the research reported here is the re-design, analysis and optimization of our newly developed neural network fuzzy adaptive controller model for complex processes capable of learning fuzzy control rules using process data and improving its control through on-line adaption. The learned improvement is according to a performance objective function that provides evaluative feedback; this performance objective is broadly defined to meet long-range goals over time. Although fuzzy control had proven effective for complex, nonlinear, imprecisely-defined processes for which standard models and controls are either inefficient, impractical or cannot be derived, the state of the art prior to our work showed that procedures for deriving fuzzy control, however, were mostly ad hoc heuristics. The learning ability of neural networks was exploited to systematically derive fuzzy control and permit on-line adaption and in the process optimize control. The operation of neural networks integrates very naturally with fuzzy logic. The neural networks which were designed and tested using simulation software and simulated data, followed by realistic industrial data were reconfigured for application on several platforms as well as for the employment of improved algorithms. The statistical procedures of the learning process were investigated and evaluated with standard statistical procedures (such as ANOVA, graphical analysis of residuals, etc.). The computational advantage of dynamic programming-like methods of optimal control was used to permit on-line fuzzy adaptive control. Tests for the consistency, completeness and interaction of the control rules were applied. Comparisons to other methods and controllers were made so as to identify the major advantages of the resulting controller model. Several specific modifications and extensions were made to the original controller. Additional modifications and explorations have been proposed for further study. Some of these are in progress in our laboratory while others await additional support. All of these enhancements will improve the attractiveness of the controller as an effective tool for the on line control of an array of complex process environments.

Esogbue, Augustine O.↗

NASA NTRS2001

Environmental Barrier Coatings for Silicon-Based Ceramics

Silicon-based ceramics, such as SiC fiber-reinforced SiC (SiC/SiC ceramic matrix composites (CMC) and monolithic silicon nitride (Si3N4), are prime candidates for hot section structural components of next generation gas turbine engines. Silicon-based ceramics, however, suffer from rapid surface recession in combustion environments due to volatilization of the silica scale via reaction with water vapor, a major product of combustion. Therefore, application of silicon-based ceramic components in the hot section of advanced gas turbine engines requires development of a reliable method to protect the ceramic from environmental attack. An external environmental barrier coating (EBC) is considered a logical approach to achieve protection and CP long-term stability. The first generation EBC consisted of two layers, mullite (3Al2O3-2SiO2) bond coat and yttria-stabilized zirconia (YSZ, ZrO2-8 Wt.% Y2O3) top coat. Second generation EBCs, with substantially improved performance compared with the first generation EBC, were developed in the NASA High Speed Research-Enabling Propulsion Materials (HSR-EPM) Program. The first generation EBC consisted of two layers, mullite (3Al2O3-2SiO2) bond coat and yttria-stabilized zirconia (YSZ, ZrO2-8 wt.% Y2O3) top coat. Second generation EBCs, with substantially improved performance compared with the first generation EBC, were developed in the NASA High Speed Research-Enabling Propulsion Materials (HSR-EPM) Program (5). They consist of three layers, a silicon first bond coat, a mullite or a mullite + BSAS (BaO(1-x)-SrO(x)-Al2O3-2SiO2) second bond coat, and a BSAS top coat. The EPM EBCs were applied on SiC/SiC CMC combustor liners in three Solar Turbines (San Diego, CA) Centaur 50s gas turbine engines. The combined operation of the three engines has accumulated over 24,000 hours without failure (approximately 1,250 C maximum combustor liner temperature), with the engine in Texaco, Bakersfield, CA, accumulating about 14,000 hours. As the commercialization of Si-based ceramic components in gas turbines is on the horizon, a major emphasis is placed on EBCs for two reasons. First, they are absolute necessity for the protection of Si-based ceramics from water vapor. Second, they can enable a major enhancement in the performance of gas turbines by creating temperature gradients with the incorporation of a low thermal conductivity layer. Thorough understanding of current state-of-the-art EBCs will provide the foundation upon which development of future EBCs will be based. Phase stability and thermal conductivity of EPM EBCs are published elsewhere. This paper will discuss the chemical/environmental durability and silica volatility of EPM EBCs and their impact on the coating's upper temperature limit.

Lee, Kang N.↗

NASA NTRS2003

Development of Algorithms for Control of Humidity in Plant Growth Chambers

Algorithms were developed to control humidity in plant growth chambers used for research on bioregenerative life support at Kennedy Space Center. The algorithms used the computed water vapor pressure (based on measured air temperature and relative humidity) as the process variable, with time-proportioned outputs to operate the humidifier and de-humidifier. Algorithms were based upon proportional-integral-differential (PID) and Fuzzy Logic schemes and were implemented using I/O Control software (OPTO-22) to define and download the control logic to an autonomous programmable logic controller (PLC, ultimate ethernet brain and assorted input-output modules, OPTO-22), which performed the monitoring and control logic processing, as well the physical control of the devices that effected the targeted environment in the chamber. During limited testing, the PLC's successfully implemented the intended control schemes and attained a control resolution for humidity of less than 1%. The algorithms have potential to be used not only with autonomous PLC's but could also be implemented within network-based supervisory control programs. This report documents unique control features that were implemented within the OPTO-22 framework and makes recommendations regarding future uses of the hardware and software for biological research by NASA.

Costello, Thomas A.↗

NASA NTRS2003

The 2002 NASA Faculty Fellowship Program Research Reports

Contents include the following: System Identification of X-33. Neural Network Advanced Ceramic Technology for Space Applications at NASA MSFC. Developing a MATLAB-Based Tool for Visualization and Transformation. Subsurface Stress Fields in Single Crystal (Anisotropic). Contacts Our Space Future: A Challenge to the Conceptual Artist Concept Art for Presentation and Education. Identification and Characterization of Extremophile Microorganisms. Significant to Astrobiology. Mathematical Investigation of Gamma Ray and Neutron. Absorption Grid Patterns for Homeland Defense-Related Fourier Imaging Systems. The Potential of Microwave Radiation for Processing Martian Soil. Fuzzy Logic Trajectory Design and Guidance for Terminal Area.

Bland, J.↗

NASA NTRS1989

Hierarchical Ada robot programming system (HARPS)- A complete and working telerobot control system based on the NASREM model

HARPS is a telerobot control system that can perform some simple but useful tasks. This capability is demonstrated by performing the ORU exchange demonstration. HARPS is based on NASREM (NASA Standard Reference Model). All software is developed in Ada, and the project incorporates a number of different CASE (computer-aided software engineering) tools. NASREM was found to be a valid and useful model for building a telerobot control system. Its hierarchical and distributed structure creates a natural and logical flow for implementing large complex robust control systems. The ability of Ada to create and enforce abstraction enhanced the implementation of such control systems.

Leake, Stephen↗

NASA NTRS1984

On the utilization of engineering knowledge in design optimization

Some current research work conducted at the University of Michigan is described to illustrate efforts for incorporating knowledge in optimization in a nontraditional way. The incorporation of available knowledge in a logic structure is examined in two circumstances. The first examines the possibility of introducing global design information in a local active set strategy implemented during the iterations of projection-type algorithms for nonlinearly constrained problems. The technique used algorithms for nonlinearly constrained problems. The technique used combines global and local monotinicity analysis of the objective and constraint functions. The second examines a knowledge-based program which aids the user to create condigurations that are most desirable from the manufacturing assembly viewpoint. The data bank used is the classification scheme suggested by Boothroyd. The important aspect of this program is that it is an aid for synthesis intended for use in the design concept phase in a way similar to the so-called idea-triggers in creativity-enhancement techniques like brain-storming. The idea generation, however, is not random but it is driven by the goal of achieving the best acceptable configuration.

Papalambros, P.↗

NASA NTRS1987

A preliminary study of Mars rover/sample return missions

The Solar System Exploration Committee (SSEC) of the NASA Advisory Council recommends that a Mars Sample Return mission be undertaken before the year 2000. Comprehensive studies of a Mars Sample Return mission have been ongoing since 1984. The initial focus of these studies was an integrated mission concept with the surface rover and sample return vehicle elements delivered to Mars on a single launch and landed together. This approach, to be carried out as a unilateral U.S. initiative, is still a high priority goal in an Augmented Program of exploration, as the SSEC recommendation clearly states. With this background of a well-understood mission concept, NASA decided to focus its 1986 study effort on a potential opportunity not previously examined; namely, a Mars Rover/Sample Return (MRSR) mission which would involve a significant aspect of international cooperation. As envisioned, responsibility for the various mission operations and hardware elements would be divided in a logical manner with clearly defined and acceptable interfaces. The U.S. and its international partner would carry out separately launched but coordinated missions with the overall goal of accomplishing in situ science and returning several kilograms of surface samples from Mars. Important considerations for implementation of such a plan are minimum technology transfer, maximum sharing of scientific results, and independent credibility of each mission role. Under the guidance and oversight of a Mars Exploration Strategy Advisory Group organized by NASA, a study team was formed in the fall of 1986 to develop a preliminary definition of a flight-separable, cooperative mission. The selected concept assumes that the U.S. would undertake the rover mission with its sample collection operations and our international partner would return the samples to Earth. Although the inverse of these roles is also possible, this study report focuses on the rover functions of MRSR because rover operations have not been studied in as much detail as the sample return functions of the mission.

Source record↗

NASA NTRS2003

Hyper-X Stage Separation Trajectory Validation Studies

An independent twelve degree-of-freedom simulation of the X-43A separation trajectory was created with the Program to Optimize Simulated trajectories (POST II). This simulation modeled the multi-body dynamics of the X-43A and its booster and included the effect of two pyrotechnically actuated pistons used to push the vehicles apart as well as aerodynamic interaction forces and moments between the two vehicles. The simulation was developed to validate trajectory studies conducted with a 14 degree-of-freedom simulation created early in the program using the Automatic Dynamic Analysis of Mechanics Systems (ADAMS) simulation software. The POST simulation was less detailed than the official ADAMS-based simulation used by the Project, but was simpler, more concise and ran faster, while providing similar results. The increase in speed provided by the POST simulation provided the Project with an alternate analysis tool. This tool was ideal for performing separation control logic trade studies that required the running of numerous Monte Carlo trajectories.

Tartabini, Paul V.↗

NASA NTRS2024

Final Technical Report for CMSC 838L

This paper describes Rahul Vishnoi’s final project supporting in his Graduate School curriculum CMSC 838L, Advanced Topics in Programming Languages and Computer Architecture. This project was selected to intersect with his work as a Pathways Intern supporting Code 583, the Ground Software Systems Branch, at NASA’s Goddard Space Flight Center (GSFC). In this project, Field Programmable Gate Array (FPGA) hardware from Xilinx is used to replace and offload processor and memory-intensive computations from a microcontroller/Processing System (PS) to the FPGA Programmable Logic (PL). An interface between the PL and PS in the form of a C library allows for this bridging of capability.

Microcontroller, FPGA, Embedded Development, Xilin↗

DOE OSTI2018

Zero Energy University Campuses: A 2018 Progress Update on Reaching Campus Energy Goals: Preprint

Many universities have aggressive energy-reduction and climate action plans. To reach these goals, leading universities have developed a suite of common energy-efficiency and renewable generation strategies. In this paper, we present a common set of approaches across the following areas: zero energy campus definitions and planning, best practices for including energy targets in new construction procurement contracts and design guidelines, implementing pilot new construction zero energy projects, aggressively implementing best-in-class laboratory energy-efficiency strategies, planning for and optimizing on-site and off-site renewable energy projects, and high-performance district energy systems. Best practices are compiled from various experiences, including programs funded by the U.S. Department of Energy, Energy Efficiency and Renewable Energy program. The summary of these best practices is to reduce campus energy use and then meet the remaining campus energy needs with renewable energy. The fivestep process to developing and implementing campus energy-reduction plans is described: 1) determine baseline energy consumption, 2) analyze technology options, 3) develop a plan and set priorities, 4) implement the plan, and 5) evaluate progress. The process follows a logical hierarchy of actions to evaluate options by energy sector and set specific targets. It encompasses all energy systems on campus, recognizing that campus-wide measures have increased potential for reducing energy use. Common strategies are explained along with examples and results.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2018

Zero Energy University Campuses: A 2018 Progress Update on Reaching Campus Energy Goals

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2016

Strategies for Decommissioning the Fuel Storage and Reprocessing Complex at Chalk River Laboratories - 16183

For over 60 years, Canadian Nuclear Laboratories (CNL), previously Atomic Energy of Canada Limited (AECL), has been a world leader in developing peaceful and innovative applications from nuclear technology. Resulting from these years of nuclear research there are legacy liabilities consisting of outdated and unused research facilities and buildings, a wide variety of buried and stored wastes, and affected lands. In 2006, the Government of Canada established the Nuclear Legacy Liabilities Program (NLLP) to safely and cost-effectively eliminate, to the extent practicable, the nuclear legacy liabilities. The National Research Experimental (NRX) fuel rod storage and handling facility, as well as two dedicated fuel reprocessing facilities at the Chalk River Laboratories (CRL) known as the Building 200 (B200) Complex, are examples of these legacy liabilities. It is planned to remove these facilities as part of a logical progression of activities to reduce CNL's liabilities under the NLLP and to prepare the property for the physical redevelopment of the CRL site. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2017

Social relations: A critical reflection on the notion of social impacts as change

This article seeks to reflect upon the dominant conception of social impacts as the change produced by development projects and programs, and the ways in which those affected perceive and experience them. Identifying change may be a necessary but not sufficient step in acknowledging the complexity of social life. Engaging with critical scholarship produced in the fields of both social impact assessment (SIA) and of the social studies of technical/planned interventions, I discuss how the understanding of social impacts as change responds ultimately to a causal–instrumental logic that, in order to make sense of the complexity of social life, tends to reduce it to a series of variables and matrices. I suggest a complementary dialectical approach focusing on social relations. This approach, allows an alternative means of analysing social impacts concerning the way policies and projects reconfigure conditions and possibilities on a societal level. To accomplish this, and in order to go beyond the sequence of potential impacts (or changes) and their generic indicators, I propose a set of analytical questions that highlight how social relations are structured. Besides, on the assumption that development is both a form of governance and a space of contestation, negotiation, and activism, this approach may contribute to further the potential for reflection and mobilisation that the practice of SIA presents. - Highlights: •Change, which is inherent to social life, is insufficient to determine social impacts. •The critique of causal-instrumental logic provides insights to reflect on social impacts. •Social impacts should rather refer to how interventions reconfigure social relations. •The complex, mutually constitutive nature of social phenomena may thus be recognized. •SIA should go beyond change to the understanding of its socio-political significance.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2019

One- and Two-Qubit Gates: Rabi Technique and Single Unipolar Pulses

Methods for controlling states of interacting superconducting flux qubits using power-efficient devices of fast single-quantum logic (Josephson nonlinearity cavities) are studied. One- and two-qubit quantum logical operations performed within the conventional control technique using Rabi pulses and using picosecond single unipolar magnetic field pulses are comparatively analyzed. It is shown that all main operations can be implemented with an accuracy of better than 97% due to optimization of the shape and parameters of unipolar control pulses (associated with, e.g., propagation of fluxons in transmission lines). The efficiency of the developed technique for programming a two-qubit quantum processor implementing the simplest Deutsch–Jozsa algorithm is demonstrated.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗