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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 1,333 records · Page 74
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Object-oriented development

Object Oriented Development (OOD) is one of the extremely few software development methods actually designed for modern Ada language, real-time, embedded applications. OOD is a significant improvement over more traditional functional decomposition and modeling methods in that ODD: Better manages the size, complexity, and concurrancy of today's systems; Better addresses important software engineering principles such as abstract data types, levels of abstraction, and information hiding; Produces a better design that more closely matches reality; Produces more maintainable software by better localizing data and thus limiting the impact of requirements changes; and Specifically exploits the power of Ada. OOD is further explored in detail.

Firesmith, Donald G.↗
NASA NTRS2013

Leak Mitigation in Mechanically Pumped Fluid Loops for Long Duration Space Missions

Mechanically pumped fluid loops (MPFLs) are increasingly considered for spacecraft thermal control. A concern for long duration space missions is the leak of fluid leading to performance degradation or potential loop failure. An understanding of leak rate through analysis, as well as destructive and non-destructive testing, provides a verifiable means to quantify leak rates. The system can be appropriately designed to maintain safe operating pressures and temperatures throughout the mission. Two MPFLs on the Mars Science Laboratory Spacecraft, launched November 26, 2011, maintain the temperature of sensitive electronics and science instruments within a -40 deg C to 50 deg C range during launch, cruise, and Mars surface operations. With over 100 meters of complex tubing, fittings, joints, flex lines, and pumps, the system must maintain a minimum pressure through all phases of the mission to provide appropriate performance. This paper describes the process of design, qualification, test, verification, and validation of the components and assemblies employed to minimize risks associated with excessive fluid leaks from pumped fluid loop systems.

thermal controls↗
NASA NTRS2000

Object-oriented Approach to High-level Network Monitoring and Management

An absolute prerequisite for the management of large investigating methods to build high-level monitoring computer networks is the ability to measure their systems that are built on top of existing monitoring performance. Unless we monitor a system, we cannot tools. Due to the heterogeneous nature of the hope to manage and control its performance. In this underlying systems at NASA Langley Research Center, paper, we describe a network monitoring system that we use an object-oriented approach for the design, we are currently designing and implementing. Keeping, first, we use UML (Unified Modeling Language) to in mind the complexity of the task and the required model users' requirements. Second, we identify the flexibility for future changes, we use an object-oriented existing capabilities of the underlying monitoring design methodology. The system is built using the system. Third, we try to map the former with the latter. APIs offered by the HP OpenView system.

Mukkamala, Ravi↗
DOE OSTI2025

Harnessing ionic complexity: A modeling approach for hierarchical ionic circuit design

Since the 1950s, soft ionic devices have evolved from individual components to an expanding library of sensors, actuators, signal transmitters, and processors. However, integrating these components into complex, multifunctional systems remains challenging due to the nonintuitive and nonlinear interactions between ionic elements. In this work, we address these fundamental challenges by developing a lumped element model that enables interrogation of the physics that governs ionic circuits, as well as rapid design and optimization. Our model captures features specific to ionic charge carriers, while preserving the hierarchical design flexibility and computational efficiency of traditional circuit modeling. We demonstrate that our model can not only fit individual device behavior but also accurately predict the behavior of larger circuits formed by combining those devices. Additionally, we show how our tool utilizes the intrinsic nonlinearities of ionic systems to enable extended functionality, revealing how factors such as ion enrichment, ion leakage, and polymer charge density influence performance. Lastly, we present a fully ionic power supply, sensor, control system, and actuator for a soft robot that adapts its motion in response to environmental salt, illustrating the tool’s potential to accelerate advancements in chemical sensing, biointerfacing, biomimetic systems, and adaptive materials.

42 ENGINEERING↗
NASA NTRS1993

Design, analysis, and testing of high frequency passively damped struts

Objectives of the research are: (1) to develop design requirements for damped struts to stabilize control system in the high frequency cross-over and spill-over range; (2) to design, fabricate and test viscously damped strut and viscoelastically damped strut; (3) to verify accuracy of design and analysis methodology of damped struts; and (4) to design and build test apparatus, and develop data reduction algorithm to measure strut complex stiffness. In order to meet the stringent performance requirements of the SPICE experiment, the active control system is used to suppress the dynamic responses of the low order structural modes. However, the control system also inadvertently drives some of the higher order modes unstable in the cross-over and spill-over frequency range. Passive damping is a reliable and effective way to provide damping to stabilize the control system. It also improves the robustness of the control system. Damping is designed into the SPICE testbed as an integral part of the control-structure technology.

Yiu, Y. C.↗
NASA NTRS1996

Advanced Manufacturing of Superconducting Magnets

The development of specialized materials, processes, and robotics technology allows for the rapid prototype and manufacture of superconducting and normal magnets which can be used for magnetic suspension applications. Presented are highlights of the Direct Conductor Placement System (DCPS) which enables automatic design and assembly of 3-dimensional coils and conductor patterns using LTS and HTS conductors. The system enables engineers to place conductors in complex patterns with greater efficiency and accuracy, and without the need for hard tooling. It may also allow researchers to create new types of coils and patterns which were never practical before the development of DCPS. The DCPS includes a custom designed eight-axis robot, patented end effector, CoilCAD(trademark) design software, RoboWire(trademark) control software, and automatic inspection.

Senti, Mark W.↗
NASA NTRSDate not supplied

Using Systems Engineering to Develop an Integrated Crew Health and Performance System to Mitigate Risk for Human Exploration Missions

New space exploration missions are currently being designed to take humanity beyond low Earth orbit (LEO) to cis-lunar space, the lunar surface, and eventually to Mars. These missions carry increased risks due to a number of factors, including distance from Earth, exposure to deep space hazards, reduced capacity and ability to resupply and evacuate, and increased communication delays. As distance from Earth grows and mission length increases, a growing proportion of mission risk can be attributed to the “human system.” Almost twenty years ago, the Institute of Medicine in the United States recommended the early and complete integration of the human system into the spacecraft and mission design process to mitigate this increased risk inherent in exploration missions. Exploration missions will require increasing levels of crew self-sufficiency that will challenge the current operational paradigms established in LEO. Enabling progressive Earth independence requires management of the increasingly complex interactions among spacecraft systems and integration of all the data and functions that affect human health and performance into one coordinated system –the Crew Health and Performance (CHP) system. This system is a critical spacecraft system that is analogous to other systems such as propulsion, guidance and navigation, or avionics. Design and integration of the CHP system requires the evidence-based merger of typically disparate disciplines such as medicine, human factors, and life support system design, using systems engineering (SE) practices. SE provides traceability of spacecraft requirements and enables reliable and repeatable trade space analysis of the many competing options for hardware and software to be included in the mission architecture. The approach described here enables spacecraft and mission designers to align the scope of a CHP system with mission specific requirements, decrease risk to the crew, and increase the probability of mission success.

Kerry McGuire↗
DOE OSTI2022

Field validation of data-driven BSDF and peak extraction models for light-scattering fabric shades

Shading and daylighting systems affect cooling, heating, and lighting energy use by modulating solar radiation through the building façade. Characterizing shading systems holistically and accurately helps designers and engineers evaluate shading systems to achieve energy and non-energy performance goals. These complex fenestration systems can be modeled using Bidirectional Scattering Distribution Functions (BSDF), which map incident radiation to hemispherical distributions of outgoing radiation. Data-driven, tabulated BSDFs are derived from interpolated goniophotometer measured data, then sampled during the raytracing calculation. A peak extraction (PE) algorithm was developed to circumvent limits in BSDF angular resolution, where the specular peak is extracted during simulation by evaluating the BSDF in the through direction and surrounding region. The objective of this study was to validate this measurement and modeling workflow using field monitored data from a full scale testbed with eleven installed fabrics of different weaves, openness factors, and colors and assess the accuracy of the workflow under different adaptation and contrast conditions. Test conditions were limited to clear sky conditions with the sun in the field of view. Results showed that, for tensor tree datasets, vertical illuminance, solar luminance (2.5° apex), and daylight glare probability (DGP) were predicted to within a mean bias error (MBE) error of -456 lx (-12.3%), -3.46e5 (-38.4%), and -0.042 (-7.8%) when full PE occurred. With a binary classification of glare/ no glare, DGP was predicted accurately with a true positive rate of 0.98 and true negative rate of 1.0 using tensor tree data and less accurately with Klems BSDF data, particularly for cases of no glare. The workflow may be of insufficient accuracy to distinguish borderline performance between fabrics using the four-point glare scale, particularly under low adaptation, high contrast daylit conditions. Errors were due to reductions in peak shape and intensity across the BSDF interpolation and data reduction workflow. Future work is needed to better preserve measurement fidelity during interpolation and sampling, which in turn will improve PE performance.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2023

New High-Entropy Perovskite Oxides with Increased Reducibility and Stability for Thermochemical Hydrogen Generation

This project aims to design, synthesize, and test a transformative class of High-Entropy Perovskite Oxides (HEPOs) as redox oxides to enable thermochemical hydrogen generation with improved stability, kinetics, and efficiency. These developed HEPOs are expected to demonstrate improved kinetics with oxygen surface exchange coefficient ( k > 7.5×10 -4 cm/s) in Budget Period (BP) 1, retain its structural stability in a broad range of oxygen non-stoichiometry (Δδ > 0.15) at a low operating reduction temperature of T red < 1400°C in BP 2, and deliver a H 2 yield of over 400 µmol per gram of oxide and high stability with less than 20% degradation after at least 50 cycles in BP 3. This project is feasible due to the unique thermodynamic properties (simultaneously increased reducibility and phase stability) and kinetic characters (stability against particle coarsening and potentially enhanced oxygen transport and surface reaction kinetics) of such HEPOs, and it is enabled by a unique active learning computational design approach. Computational studies have been conducted to investigate the oxygen vacancy formation in complex perovskite systems. * Accurate prediction of V O .. concentration with disordered A-site cations in Fe-based high-entropy perovskite oxides * Combined MC/DFT computation elucidates the mechanism of Co preference on the redox due to the strain introduced by local distortion. In this project, we explored a large number (~150) of perovskite compositions, which are listed in Tables 2 – 4). * All perovskite specimens have been synthesized through a high-throughput high-energy ball milling process, followed by the conventional sintering process. * XRD, SEM/EDS and TGA were performed to confirm the crystal structure, phase homogeneity and oxygen non-stoichiometry for compositionally complex perovskite oxides (CCPOs). * 110 compositions show single-phase from XRD * Unusual aliovalent doping effects in medium-entropy perovskite compositions. * V-shape relation between Δδ vs. x (La 1-x Sr x )(Mn 1/3 Fe 1/3 Ti 1/3 )O 3 * The highest reported hydrogen production for the CCPOs made in this project ( T re = 1350 ºC 30 min, T Ox = 1100 ºC 30 min) * B-site mixing (La 0.8 Sr 0.2 )(Mn 0.2 Fe 0.2 Co 0.4 Al 0.2 )O 3 : 89.97 ± 2.73 mmol H2 /mol oxide (395 ± 10 μmol/g oxide ) (i) No phase transformation during reactions when Co molar ratio is less than 61% (ii) Balance between intrinsic kinetics (oxygen surface exchange) and thermodynamics (oxygen non-stoichiometry) (iii) Preference of Co identified by in-situ XPS * A-site mixing (La 1/6 Pr 1/6 Nd 1/6 Gd 1/6 Ba 1/6 Sr1/6)MnO 3 : 98.48 mmol H2 /mol oxid e (~415 μmol/g oxide )

08 HYDROGEN↗
NASA NTRS1987

Aeropropulsion 1987. Session 2: Aeropropulsion Structures Research

Aeropropulsion systems present unique problems to the structural engineer. The extremes in operating temperatures, rotational effects, and behaviors of advanced material systems combine into complexities that require advances in many scientific disciplines involved in structural analysis and design procedures. This session provides an overview of the complexities of aeropropulsion structures and the theoretical, computational, and experimental research conducted to achieve the needed advances.

Source record↗
NASA NTRS1990

A comparison of different models for beam vibrations from the standpoint of control design

Different models for beam vibrations are analyzed from the standpoint of designing finite-dimensional controllers to stabilize the beam vibrations. A distributed system described by an undamped Euler-Bernoulli equation cannot be stabilized by any finite-dimensional controller, i.e., any controller which can be described an ordinary differential equation with constant coefficients. If viscous damping is included, a similar problem occurs in that all the poles can not be moved to the left of a given vertical line. These negative results should be interpreted as a commentary on the limitations of these models, rather than on the control of real beams. If a Rayleigh damping model is used, a finite-dimensional controller may be designed to move the closed loop system poles essentially as far to the left in the complex plane as desired. This result will also hold for certain hysteresis damping models. This has implications for the settling time of the vibrations.

Morris, K. A.↗
NASA NTRS1992

A stochastic approach to robust broadband structural control

Viewgraphs on a stochastic approach to robust broadband structural control are presented. Topics covered include: travelling wave model; dereverberated mobility model; computation of dereverberated mobility; power flow; impedance matching; stochastic systems; control problem; control of stochastic systems; using cost functional; Bernoulli-Euler beam example; compensator design; 'power' dual variables; dereverberation of complex structure; and dereverberated transfer function.

Macmartin, Douglas G.↗
NASA NTRS1992

High-speed civil transport - Advanced flight deck challenges

This paper presents the results of a nine month study of the HSCT flight deck challenges and assessment of its benefits. Operational requirements are discussed and the most significant findings for specified advanced concepts are highlighted. These concepts are a no nose-droop configuration, a far forward cockpit location and advanced crew monitoring and control of complex systems. Results indicate that the no nose-droop configuration is critically dependent on the design and development of a safe, reliable and certifiable synthetic vision system (SVS). This configuration would cause significant weight, performance and cost penalties. A far forward cockpit configuration with a tandem seating arrangement allows either an increase in additional payload or potential downsizing of the vehicle leading to increased performance efficiency and reductions in emissions. The technologies enabling such capabilities, which provide for Category III all-weather opreations on every flight represent a benefit multiplier in a 20005 ATM network in terms of enhanced economic viability and environmental acceptability.

Swink, Jay R.↗
NASA NTRS2000

About the Effect of Control on Flutter and Post-Flutter of a Supersonic/Hypersonic Cross-Sectional Wing

The control of the flutter instability and the conversion of the dangerous character of the flutter instability boundary into the undangerous one of a cross-sectional wing in a supersonic/hypersonic flow field is presented. The objective of this paper is twofold: i) to analyze the implications of nonlinear unsteady aerodynamics and physical nonlinearities on the character of the instability boundary in the presence of a control capability, and ii) to outline the effects played in the same respect by some important parameters of the aeroelastic system. As a by-product of this analysis, the implications of the active control on the linearized flutter behavior of the system are captured and emphasized. The bifurcation behavior of the open/closed loop aeroelastic system in the vicinity of the flutter boundary is studied via the use of a new methodology based on the Liapunov First Quantity. The expected outcome of this study is: a) to greatly enhance the scope and reliability of the aeroelastic analysis and design criteria of advanced supersonic/hypersonic flight vehicles and, b) provide a theoretical basis for the analysis of more complex nonlinear aeroelastic systems.

Marzocca, Piergiovanni↗
NASA NTRS2009

Sheet Membrane Spacesuit Water Membrane Evaporator Thermal Test

For future lunar extravehicular activities (EVA), one method under consideration for rejecting crew and electronics heat involves evaporating water through a hydrophobic, porous Teflon(Registered Trademark) membrane. A Spacesuit Water Membrane Evaporator (SWME) prototype using this membrane was successfully tested by Ungar and Thomas (2001) with predicted performance matching test data well. The above referenced work laid the foundation for the design of a compact sheet membrane SWME development unit for use in the Constellation System Spacesuit Element Portable Life Support System (Vogel and et. al., ICES 2008). Major design objectives included minimizing mass, volume, and manufacturing complexity while rejecting a minimum of 810 watts of heat from water flowing through the SWME at 91 kg/hr with an inlet temperature of 291K. The design meeting these objectives consisted of three concentric cylindrical water channels interlaced with four water vapor channels. Two units were manufactured for the purpose of investigating manufacturing techniques and performing thermal testing. The extensive thermal test measured SWME heat rejection as a function of water inlet temperatures, water flow-rates, water absolute pressures, water impurities, and water vapor back-pressures. This paper presents the test results and subsequent analysis, which includes a comparison of SWME heat rejection measurements to pretest predictions. In addition, test measurements were taken such that an analysis of the commercial-off-the-shelf vapor pressure control valve could be performed.

Trevino, Luis A.↗
NASA NTRS2009

Efficient Method for Optimizing Placement of Sensors

A computationally efficient method has been developed to enable optimization of the placement of sensors for the purpose of diagnosis of a complex engineering system (e.g., an aircraft or spacecraft). The method can be used both in (1) designing a sensor system in which the number and positions of sensors are initially not known and must be determined and (2) adding sensors to a pre-existing system to increase the diagnostic capability. The optimal-sensor-placement problem can be summarized as involving the following concepts, issues, and subproblems: a) Degree of Diagnosability - This is a concept for characterizing the set of faults that can be discriminated by use of a given set of sensors. b) Minimal Sensor Set - The idea is one of finding a minimal set of sensors that guarantees a specific degree of diagnosability. c) Minimal-Cost Sensors - In a case in which different sensors are assigned with different costs, it is desired to choose the least costly set of sensors that affords a specific degree of diagnosability.

Fijany, Amir↗
NASA NTRS1999

Interoperability Trends in Extravehicular Activity (EVA) Space Operations for the 21st Century

No other space operations in the 21 st century more comprehensively embody the challenges and dependencies of interoperability than EVA. This discipline is already functioning at an W1paralleled level of interagency, inter-organizational and international cooperation. This trend will only increase as space programs endeavor to expand in the face of shrinking budgets. Among the topics examined in this paper are hardware-oriented issues. Differences in design standards among various space participants dictate differences in the EVA tools that must be manufactured, flown and maintained on-orbit. Presently only two types of functional space suits exist in the world. However, three versions of functional airlocks are in operation. Of the three airlocks, only the International Space Station (ISS) Joint Airlock can accommodate both types of suits. Due to functional differences in the suits, completely different operating protocols are required for each. Should additional space suit or airlock designs become available, the complexity will increase. The lessons learned as a result of designing and operating within such a system are explored. This paper also examines the non-hardware challenges presented by interoperability for a discipline that is as uniquely dependent upon the individual as EVA. Operation of space suits (essentially single-person spacecrafts) by persons whose native language is not that of the suits' designers is explored. The intricacies of shared mission planning, shared control and shared execution of joint EVA's are explained. For example, once ISS is fully functional, the potential exists for two crewmembers of different nationality to be wearing suits manufactured and controlled by a third nation, while operating within an airlock manufactured and controlled by a fourth nation, in an effort to perform tasks upon hardware belonging to a fifth nation. Everything from training issues, to procedures development and writing, to real-time operations is addressed. Finally, this paper looks to the management challenges presented by interoperability in general. With budgets being reduced among all space-faring nations, the need to expand cooperation in the highly expensive field of human space operations is only going to intensify. The question facing management is not if the trend toward interoperation will continue, but how to best facilitate its doing so. Real-world EVA interoperability experience throughout the ShuttlelMir and ISS Programs is discussed to illustrate the challenges and

Miller, Gerald E.↗
NASA NTRSDate not supplied

Systems Engineering Tutorial with Case Studies

Due to the ever-growing number of complex technical problems facing our world, a Systems Engineering approach is needed to assist in successful design, build and implementation of solutions. The interdisciplinary technical structure of current systems, technical processes representing System Design, Technical Management and Product Realization are instrumental in the development and integration of new technologies into mainstream applications. This tutorial will demonstrate the application of Systems Engineering tools to these types of problems. Learning objectives include, understanding how to develop and engineer a conceptual system; understand the importance of teams, communication, requirements definition, interface control, and focus on deliverables; useful tools and techniques for each aspect of the System Engineering process including Model Based Systems Engineering which will be touched upon lightly. Some hands-on problems will be pursued especially in requirements development which is always key to a successful project. Case studies will be presented to assist in the learning process.

Systems Engineering↗