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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 1,531 records · Page 85

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DOE OSTI2018

Hydrogen Fuel-Cell Electric Hybrid Truck Demonstration (Final Technical Report)

The purpose of the project was to demonstrate three (3) fully developed, operational, advanced vehicle technology prototypes for ON-ROAD goods movement applications. The major vehicle OEM for this demonstration was Navistar International Trucks, with the fuel cell and power control hybrid technology provided and integrated by US Hybrid. CEM was to provide independent data collection and analysis, while EDF would provide education, outreach, and communication for the project. GTI managed the partnership and arranged for hydrogen fuel for the demonstration. The drayage truck is used to transfer the cargo container from/to ports in a warehouse or logistic yard. For port facilities in the Port of Houston Area, as well as virtually all other ports, drayage trucks often queue for long periods, inching along at slow speeds to await loading and unloading. During this process, the trucks are essentially idle, with conventional diesel engines continuously running and producing accompanying emissions. The ZECT would essentially power off during idle periods, or at least utilize minimal electric energy. As such, range limitation by using a gaseous fuel would be mitigated by the fact that the vehicle is not using fuel during much of its duty cycle. The project team expected the vehicle range to be about 200 miles which is well within the duty cycle requirements of the original fleet partner, Richardson Trucking. The project was intended to demonstrate commercialization and production potential, and to clearly illustrate the selected vehicle technology’s potential to reduce GHG emissions and petroleum use if implemented widely. To achieve this, the project team proposed a two-year demonstration project in the Port of Houston area to assess and track vehicle performance, and evaluate fuel savings, petroleum reduction, and emissions reduction benefits of the prototype technology. Additional time at the front end of the project was required for vehicle and support infrastructure preparation. In June 2017 the remaining project partners, which now included Air Liquide, agreed that the project would be unlikely to move forward with the vehicle demonstration, primarily due to the lack of a viable cargo truck fleet partner in the Port of Houston area willing to make a sufficient commitment of resources to operate the vehicles for the demonstration.

08 HYDROGEN↗

DOE OSTI2019

Effects of Defects on Band Structure and Excitons in WS 2 Revealed by Nanoscale Photoemission Spectroscopy

Two-dimensional materials with engineered composition and structure will provide designer materials beyond conventional semiconductors. Yet, the potentials of defect engineering remain largely untapped, because it hinges on a precise understanding of electronic structure and excitonic properties, which are not yet predictable by theory alone. In this report, we use correlative, nanoscale photoemission spectroscopy to visualize how local introduction of defects modifies electronic and excitonic properties of two-dimensional materials at the nanoscale. As a model system, we study chemical vapor deposition grown monolayer WS 2 , a prototypical, direct gap, two-dimensional semiconductor. By cross-correlating nanoscale angle-resolved photoemission spectroscopy, core level spectroscopy, and photoluminescence, we unravel how local variations in defect density influence electronic structure, lateral band alignment, and excitonic phenomena in synthetic WS 2 monolayers.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2019

TestSNAP

TestSNAP is a stand-alone prototype of the SNAP force kernel used in the LAMMPS molecular dynamics code. It contains synthetic input data (neighbor atom positions) and reference output data (forces on atoms) for several different SNAP models. The prototype performs the force calculation repeatedly, checking the results against the reference data. At the end it reports the grind time [msec/atomstep] and RMS force error [eV/A]. This allows performance experts to quickly test new hardware and software strategies, obtain a realistic performance estimate and verify that the computation was performed correctly. SAND2019-12243 M Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA0003525.

Thompson, Aidan↗

NASA NTRS1992

Domain-specific functional software testing: A progress report

Software Engineering is a knowledge intensive activity that involves defining, designing, developing, and maintaining software systems. In order to build effective systems to support Software Engineering activities, Artificial Intelligence techniques are needed. The application of Artificial Intelligence technology to Software Engineering is called Knowledge-based Software Engineering (KBSE). The goal of KBSE is to change the software life cycle such that software maintenance and evolution occur by modifying the specifications and then rederiving the implementation rather than by directly modifying the implementation. The use of domain knowledge in developing KBSE systems is crucial. Our work is mainly related to one area of KBSE that is called automatic specification acquisition. One example is the WATSON prototype on which our current work is based. WATSON is an automatic programming system for formalizing specifications for telephone switching software mainly restricted to POTS, i.e., plain old telephone service. Our current approach differentiates itself from other approaches in two antagonistic ways. On the one hand, we address a large and complex real-world problem instead of a 'toy domain' as in many research prototypes. On the other hand, to allow such scaling, we had to relax the ambitious goal of complete automatic programming, to the easier task of automatic testing.

Nonnenmann, Uwe↗

NASA NTRS2003

Novel Engineering and Fabrication Techniques Tested in Low-Noise- Research Fan Blades

A major source of fan noise in commercial turbofan engines is the interaction of the wake from the fan blades with the stationary vanes (stators) directly behind them. The Trailing Edge Blowing (TEB) project team at the NASA Glenn Research Center designed and fabricated new fan blades to study the effects of fan trailing edge blowing as a potential noise-reduction concept. The intent is to fill the rotor wake by supplying air to the rotor blade trailing edge at the proper conditions to minimize the wake deficit, and thus generate less noise. The TEB hardware is designed for the Active Noise Control Fan (ANCF) test rig in Glenn's Aeroacoustic Propulsion Laboratory. For this test, the air is fed from an external supply through the shaft of the rig. It is distributed to the base of each blade through an impeller, where it is forced into a plenum at the core of each blade. In actual engine configuration, air would most likely be bled from the compressor, but only at times when noise is an issue, such as takeoffs and landings. Glenn researchers designed and manufactured the blades in-house, using new techniques and concepts. The skins, which were designed for maximum strength in the directions of highest stress, were molded from multiple layers of carbon fiber. Considerable use was made of rapid prototyping techniques, such as laser sintering. The core was sintered from a lightweight polymer, and the retainer was CNC-machined (computer numerical control machined) from aluminum. All the components were joined with a cold-cure aerospace adhesive. These techniques and processes reduced the overall cost and allowed the new concept to be studied much sooner than would be possible using traditional fabrication methods. Since this test rig did not support the use of blade-monitoring techniques such as strain gauges, extensive bench testing was required to qualify the design. The blades were examined using a variety of methods including holography, pull tests (cyclic and failure), shake tests, rap tests, and nondestructive inspection. Acoustic testing of the ANCF fan using TEB has been ongoing since January of 2001. The fan has completed about 100 hr of testing with no structural, vibrational, or fatigue problems. Far-field acoustic measurements, in-duct mode measurements, precise hot wire surveys, and detailed performance measurements are providing data for evaluating the concept. The far-field noise data show that tone noise was reduced significantly with the initial ANCF TEB fan design. In addition, a significant reduction in unsteady stator loading has been measured, indicating the potential for stator broadband noise reduction. The acoustic benefits will be assessed and important design parameters identified to improve the ability to fully exploit any benefit provided by this technique. On the basis of the success of trailing edge blowing, Glenn plans to continue this research with a higher speed, higher pressure ratio fan operating in an acoustic wind tunnel to simulate flight conditions.

Cunningham, Cameron C.↗

NASA NTRS2006

Experimental Results for Titan Aerobot Thermo-Mechanical Subsystem Development

This paper presents experimental results on a set of 4 thermo-mechanical research tasks aimed at Titan and Venus aerobots: 1. A cryogenic balloon materials development program culminating in the fabrication and testing of a 4.6 m long blimp prototype at 93K. 2. A combined computational and experimental thermal analysis of the effect of radioisotope power system (RPS) waste heat on the behavior of a helium filled blimp hull. 3. Aerial deployment and inflation testing using a blimp 4. A proof of concept experiment with an aerobot-mounted steerable high gain antenna These tasks were supported with JPL internal R&D funds and executed by JPL engineers with substantial industry collaboration for Task #1, the cryogenic balloon materials

blimps↗

DOE OSTI2019

Prototype Ceramic HEPA Filter Testing and Filter Media Research and Development for Nuclear Facility Ventilation

This is a brief summary of recent and past Ceramic HEPA Filter research and development activities under an NNSA NSR&D funded project and describes on-going plans for FY19 work as presently planned. Prior work has evaluated concepts for a ceramic HEPA filter including ceramic support materials, filter media including electrospun filter media, and metal housing designs to accommodate the conservative temperature performance target of up to 500°C. This has been supported by modelling efforts discussed with nuclear facility system engineers and their management. The temperature and time-attemperature are based on conservative, bounding temperatures from fire analysis presented as an EFCOG best practice paper for nuclear facility safety analysis. The overall goal is to improve safety of DOE nuclear facilities during fire scenarios by developing improved filtration technology including increasing temperature performance while maintaining acceptable filter pressure drop. Ceramic filtration technology can provide robust, passive mitigation against radiological releases. The goal of the ceramic HEPA filter is to provide a HEPA filter that provides increased temperature performance in an equivalent form factor (size and shape) that is similar to existing conventional HEPA filters used in facilities. Once development is complete and qualified for use in facilities, ceramic HEPA filters could simplify and reduce safety and support system costs, as well as lower life-cycle costs. Installation, monitoring, and maintenance of active fire suppression systems, as well as other related systems, are a considerable on-going cost to nuclear facilities. Reducing the level of dependence on Safety Class and Safety Significant fire alarm and fire suppression systems could allow significant cost savings. At present we are continuing research and development efforts towards the goal of a ceramic filter design, including improved ceramic filter media, that could reduce total operation cost for facilities utilizing HEPA filters.

36 MATERIALS SCIENCE↗

DOE OSTI2019

Prototype Ceramic HEPA Filter Testing and Filter Media Research and Development for Nuclear Facility Ventilation

This is a brief summary of recent and past Ceramic HEPA Filter research and development activities under an NNSA NSR&D funded project and describes on-going plans for FY19 work as presently planned. Prior work has evaluated concepts for a ceramic HEPA filter including ceramic support materials, filter media including electrospun filter media, and metal housing designs to accommodate the conservative temperature performance target of up to 500°C. This has been supported by modelling efforts discussed with nuclear facility system engineers and their management. The temperature and time-at-temperature are based on conservative, bounding temperatures from fire analysis presented as an EFCOG best practice paper for nuclear facility safety analysis. The overall goal is to improve safety of DOE nuclear facilities during fire scenarios by developing improved filtration technology including increasing temperature performance while maintaining acceptable filter pressure drop. Ceramic filtration technology can provide robust, passive mitigation against radiological releases. The goal of the ceramic HEPA filter is to provide a HEPA filter that provides increased temperature performance in an equivalent form factor (size and shape) that is similar to existing conventional HEPA filters used in facilities. Once development is complete and qualified for use in facilities, ceramic HEPA filters could simplify and reduce safety and support system costs, as well as lower life-cycle costs. Installation, monitoring, and maintenance of active fire suppression systems, as well as other related systems, are a considerable on-going cost to nuclear facilities. Reducing the level of dependence on Safety Class and Safety Significant fire alarm and fire suppression systems could allow significant cost savings, while maintaining safety. At present we are continuing research and development efforts towards the goal of a ceramic filter design, including improved ceramic filter media, that could reduce total operation cost for facilities utilizing HEPA filters.

36 MATERIALS SCIENCE↗

DOE OSTI2021

Efficient facemask decontamination via forced ozone convection

The COVID-19 crisis has taken a significant toll on human life and the global economy since its start in early 2020. Healthcare professionals have been particularly vulnerable because of the unprecedented shortage of Facepiece Respirators (FPRs), which act as fundamental tools to protect the medical staff treating the coronavirus patients. In addition, many FPRs are designed to be disposable single-use devices, creating an issue related to the generation of large quantities of non-biodegradable waste. In this contribution, we describe a plasma-based decontamination technique designed to circumvent the shortages of FPRs and alleviate the environmental problems posed by waste generation. The system utilizes a Dielectric Barrier Discharge (DBD) to generate ozone and feed it through the fibers of the FPRs. The flow-through configuration is different than canonical ozone-based sterilization methods, in which the equipment is placed in a sealed ozone-containing enclosure without any flow through the mask polymer fibers. We demonstrate the rapid decontamination of surgical masks using Escherichia coli ( E. coli ) and Vesicular Stomatitis Virus (VSV) as model pathogens, with the flow-through configuration providing a drastic reduction in sterilization time compared to the canonical approach. We also demonstrate that there is no deterioration in mask structure or filtration efficiency resulting from sterilization. Finally, we show that this decontamination approach can be implemented using readily available tools, such as a plastic box, a glass tube, few 3D printed components, and the high-voltage power supply from a plasma globe toy. The prototype assembled for this study is portable and affordable, with effectiveness comparable to that of larger and more expensive equipment.

36 MATERIALS SCIENCE↗

DOE OSTI2017

High-Frequency Transformer Design for Modular Power Conversion From Medium-Voltage AC to 400 VDC

This paper presents a high-frequency modular medium-voltage AC (4160 VAC or 13.8 kVAC) to low-voltage DC (400 VDC) system that is scalable in order to be used for different scale microgrids. A 15 kW, 500 kHz DC/DC converter is demonstrated as the most important stage of the system overall, which can be scalable to a 225 kW 4160 VAC to 400 VDC system. Motivation of a CLLC resonant converter and its design parameters determination is carefully illustrated. The high-frequency transformer is the key element for the DC/DC converter. Then, the paper focuses on high-frequency transformer design to realize high-voltage insulation, high efficiency, and high density at the same time. Based on a split winding UU core transformer structure, transformer insulation materials and dimension parameters are determined referring to the IEEE insulation standard. The transformer magnetic loss model is reviewed based on which loss design tradeoff is carefully analyzed. Different working frequency impact on transformer design over three different core materials is also presented. Finally, a 500 kHz transformer prototype has been developed and demonstrated with the IEEE standard required insulation tests. A whole CLLC resonant converter is also present with experiments results. Here, the converter holds outstanding 98% efficiency and 2.9 kW/L power density.

42 ENGINEERING↗

DOE OSTI2021

Stacked Low-Inertia Converter or Solid-State Transformer: Modeling and Model Predictive Priority-Shifting Control for Voltage Balance

This paper presents control challenges of stacked low-inertia converter (SLIC) or cascaded reduced dc-link solid-state transformer (SST) and proposes a novel model predictive priority-shifting (MPPS) control with implicit modulator and a discrete-time large-signal model for voltage balancing and dc-link regulation. Low-inertia converters, featuring small electrolytic capacitor-less dc links, dramatically reduce cost, size, and weight compared to conventional solutions. However, without a large dc-link buffer, the input and output are tightly coupled, leading to significant control challenges. The control becomes even more challenging with these converters stacked input-series output-parallel (ISOP) for medium-voltage (MV) grid, which causes coupling between the modules besides the coupling within each module. This paper analyzes the multi-objective, multi-degree of freedom control problem, using the modular soft-switching solid-state transformer (M-S4T) as an example of the SLIC. First, distribution of control efforts under controller saturation is critical because multiple control objectives can be conflicting, especially when the module voltages are unbalanced and are being restored. The MPPS can shift the priorities to address this issue. Second, due to the low inertia and high dc-link ripple, classic space vector pulse-width modulation (SVPWM), average model with small-ripple assumption, and control design based on small-signal model cannot accurately modulate, model, and control the nonlinear reduced dc link. Therefore, a discrete-time large-signal model of the M-S4T is established to derive the predictive control in the MPPS. The MPPS and the PI control are compared in MV simulations to show the issue of applying the PI to the SLIC and the effectiveness of the MPPS for voltage balancing and dc-link regulation in a deadbeat manner. Finally, the proposed control is tested on a 5 kV ISOP SiC SST prototype to verify priority shifting to address controller saturation issue and fast and robust voltage balancing.

14 SOLAR ENERGY↗

DOE OSTI2022

Development of a 250 Degree C 15kV Supercascode Switch Using SiC JFET Technology

Tetra Corporation is developing a pulsed power drilling system for the geothermal industry. The system requires a high temperature switching technology to replace the existing technology based on Si thyristors with a temperature limit of 150 degrees C. This work focuses on the development of such switch based on a Supercascode configuration using SiC JFET technology. The development presented contains thermal models, packaging design and processes, circuit simulations and prototypes of both the Supercascode switch and the high temperature packaged SiC JFETs.

cascaded switch↗

NASA NTRS1990

Compiling knowledge-based systems from KEE to Ada

The dominant technology for developing AI applications is to work in a multi-mechanism, integrated, knowledge-based system (KBS) development environment. Unfortunately, systems developed in such environments are inappropriate for delivering many applications - most importantly, they carry the baggage of the entire Lisp environment and are not written in conventional languages. One resolution of this problem would be to compile applications from complex environments to conventional languages. Here the first efforts to develop a system for compiling KBS developed in KEE to Ada (trademark). This system is called KATYDID, for KEE/Ada Translation Yields Development Into Delivery. KATYDID includes early prototypes of a run-time KEE core (object-structure) library module for Ada, and translation mechanisms for knowledge structures, rules, and Lisp code to Ada. Using these tools, part of a simple expert system was compiled (not quite automatically) to run in a purely Ada environment. This experience has given us various insights on Ada as an artificial intelligence programming language, potential solutions of some of the engineering difficulties encountered in early work, and inspiration on future system development.

Filman, Robert E.↗

NASA NTRS1993

Integrated modeling of advanced optical systems

This poster session paper describes an integrated modeling and analysis capability being developed at JPL under funding provided by the JPL Director's Discretionary Fund and the JPL Control/Structure Interaction Program (CSI). The posters briefly summarize the program capabilities and illustrate them with an example problem. The computer programs developed under this effort will provide an unprecedented capability for integrated modeling and design of high performance optical spacecraft. The engineering disciplines supported include structural dynamics, controls, optics and thermodynamics. Such tools are needed in order to evaluate the end-to-end system performance of spacecraft such as OSI, POINTS, and SMMM. This paper illustrates the proof-of-concept tools that have been developed to establish the technology requirements and demonstrate the new features of integrated modeling and design. The current program also includes implementation of a prototype tool based upon the CAESY environment being developed under the NASA Guidance and Control Research and Technology Computational Controls Program. This prototype will be available late in FY-92. The development plan proposes a major software production effort to fabricate, deliver, support and maintain a national-class tool from FY-93 through FY-95.

Briggs, Hugh C.↗

NASA NTRS1995

Biomorphic architectures for autonomous Nanosat designs

Modern space tool design is the science of making a machine both massively complex while at the same time extremely robust and dependable. We propose a novel nonlinear control technique that produces capable, self-organizing, micron-scale space machines at low cost and in large numbers by parallel silicon assembly. Experiments using biomorphic architectures (with ideal space attributes) have produced a wide spectrum of survival-oriented machines that are reliably domesticated for work applications in specific environments. In particular, several one-chip satellite prototypes show interesting control properties that can be turned into numerous application-specific machines for autonomous, disposable space tasks. We believe that the real power of these architectures lies in their potential to self-assemble into larger, robust, loosely coupled structures. Assembly takes place at hierarchical space scales, with different attendant properties, allowing for inexpensive solutions to many daunting work tasks. The nature of biomorphic control, design, engineering options, and applications are discussed.

Hasslacher, Brosl↗

NASA NTRS2003

High Power mm-Wave Transmitter System for Radar or Telecommunications

Future NASA deep space missions able to provide tens of kilo-watts of spacecraft DC power, make it feasible to employ high power RF telecommunications systems. Traditional flight systems (e.g., Cassini), constrained by limited DC power, used a single high-gain 4m Cassegrain reflector fed by a single lower power (20W) transmitter. Increased available DC power means that high power (1000 W) transmitters can be used. Rather than continue building traditional single-transmitter systems it now becomes feasible to engineer and build multi-element active arrays that can illuminate a dish. Illuminating a 2m dish with a spherical wavefront from an offset 1kW active array can provide sufficient ERP (Effective Radiated Power) when compared to a larger Cassegrain dish. Such a system has the advantage of lower mass, lower volume, improved reliability, less stringent pointing requirements, lower cost and risk. We propose to design and build a prototype Ka-band transmit antenna with an active sub-array using 125W TWTAs. The system could be applied to a telecommunications downlink or radar transmitter used for missions such as JIMO.

Stride, S. L.↗

NASA NTRS2003

Performance of the CELSS Antarctic Analog Project (CAAP) crop production system

Regenerative life support systems potentially offer a level of self-sufficiency and a decrease in logistics and associated costs in support of space exploration and habitation missions. Current state-of-the-art in plant-based, regenerative life support requires resources in excess of allocation proposed for candidate mission scenarios. Feasibility thresholds have been identified for candidate exploration missions. The goal of this paper is to review recent advances in performance achieved in the CELSS Antarctic Analog Project (CAAP) in light of the likely resource constraints. A prototype CAAP crop production chamber has been constructed and operated at the Ames Research Center. The chamber includes a number of unique hardware and software components focused on attempts to increase production efficiency, increase energy efficiency, and control the flow of energy and mass through the system. Both single crop, batch production and continuous cultivation of mixed crops production studies have been completed. The crop productivity as well as engineering performance of the chamber are described. For each scenario, energy required and partitioned for lighting, cooling, pumping, fans, etc. is quantified. Crop production and the resulting lighting efficiency and energy conversion efficiencies are presented. In the mixed-crop scenario, with 27 different crops under cultivation, 17 m2 of crop area provided a mean of 515 g edible biomass per day (85% of the approximate 620 g required for one person). Enhanced engineering and crop production performance achieved with the CAAP chamber, compared with current state-of-the-art, places plant-based life support systems at the threshold of feasibility. c2002 Published by Elsevier Science Ltd on behalf of COSPAR.

Lettuce/growth & development↗

NASA NTRS2011

A Review of the NASA MLAS Flight Demonstration

The NASA Engineering and Safety Center (NESC) has tested the Max Launch Abort System (MLAS) as a risk-mitigation design should problems arise with the baseline Orion spacecraft launch abort design. The Max in MLAS is not Maximum, but rather dedicated to Max Faget, the renowned NASA Spacecraft designer. In July 2009, the mission was flown, with great success, from the NASA Wallops Flight Facility. The MLAS flight test vehicle prototype consists of a boost skirt, coast skirt, and the MLAS fairing itself, which houses an Orion Command Module (CM) boilerplate. The objective of the MLAS flight test is to reorient the fairing with the CM, weighing approximately 29,000 lbs and traveling 290 fps, 180 degrees to an orientation suitable for the release of the CM during a pad abort or low altitude abort. The boost and coast skirts provide the necessary thrust and stability to establish the flight test conditions and are released prior to the reorientation of the fairing. A secondary test objective after successful release of the CM from the fairing is to demonstrate the removal of the CM forward bay cover (FBC) with the CM drogue parachutes, and subsequent deployment of the CM main parachutes attached to the FBC. Although multiple parachute deployments are used in the MLAS flight test vehicle to complete its objective, there are only two parachute types employed in the flight test. Five of the nine parachutes used for MLAS are 27.6 ft DO ribbon parachutes already proven as a spin/stall parachute for military aircraft, and the remaining four are G-12 cargo parachutes modified for increased strength and reefing. This paper presents an overview of the 27.6 ft DO ribbon parachute system employed on the MLAS flight test vehicle for coast skirt separation, fairing reorientation, and as CM drogue parachutes. Discussion will include: the process used to select this design; descriptions of all components of the parachute system; the minor modifications necessary to adapt the parachute to the MLAS program; the techniques used to analyze the parachute for the multiple roles it performs including discussions of how the evolution of the program affected parachute usage and analysis; a summary of the results of the highly successful flight test, including video of the flight test; and an overview of the subsequent post-test analysis.

Taylor, Anthony P.↗