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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 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS1983

Advanced Gas Turbine (AGT) technology development

A 74.5 kW (100 hp) automotive gas turbine was evaluated. The engine structure, bearings, oil system, and electronics were demonstrated and no shaft dynamics or other vibration problem were encountered. Areas identified during the five tests are the scroll retention features, and transient thermal deflection of turbine backplates. Modifications were designed. Seroll retention is addressed by modifying the seal arrangement in front of the gasifier turbine assembly, which will increase the pressure load on the scroll in the forward direction and thereby increase the retention forces. the backplate thermal deflection is addressed by geometric changes and thermal insulation to reduce heat input. Combustor rig proof testing of two ceramic combustor assemblies was completed. The combustor was modified to incorporate slots and reduce sharp edges, which should reduce thermal stresses. The development work focused on techniques to sinter these barrier materials onto the ceramic rotors with successes for both material systems. Silicon carbide structural parts, including engine configuration gasifier rotors (ECRs), preliminary gasifier scroll parts, and gasifier and power turbine vanes are fabricated.

Source record↗
NASA NTRS2015

Space Structure Development

The duration of my Summer 2015 Internship Tour at NASA's Johnson Space Center was spent working in the Structural Engineering Division's Structures Branch. One of the two main roles of the Structures Branch, ES2, is to ensure the structural integrity of spacecraft vehicles and the structural subsystems needed to support those vehicles. The other main objective of this branch is to develop the lightweight structures that are necessary to take humans beyond Low-Earth Orbit. Within ES2, my four projects involved inflatable space structure air bladder material testing; thermal and impact material testing for spacecraft windows; structural analysis on a joint used in the Boeing CST-100 airbag system; and an additive manufacturing design project.

Smith, Thomas↗
NASA NTRS1988

Lewis Structures Technology, 1988. Volume 2: Structural Mechanics

Lewis Structures Div. performs and disseminates results of research conducted in support of aerospace engine structures. These results have a wide range of applicability to practitioners of structural engineering mechanics beyond the aerospace arena. The engineering community was familiarized with the depth and range of research performed by the division and its academic and industrial partners. Sessions covered vibration control, fracture mechanics, ceramic component reliability, parallel computing, nondestructive evaluation, constitutive models and experimental capabilities, dynamic systems, fatigue and damage, wind turbines, hot section technology (HOST), aeroelasticity, structural mechanics codes, computational methods for dynamics, structural optimization, and applications of structural dynamics, and structural mechanics computer codes.

Source record↗
NASA NTRS2011

Puncture Self-Healing Polymers for Aerospace Applications

Space exploration launch costs on the order of $10K per pound provide ample incentive to seek innovative, cost-effective ways to reduce structural mass without sacrificing safety and reliability. Damage-tolerant structural systems can provide a route to avoiding weight penalty while enhancing vehicle safety and reliability. Self-healing polymers capable of spontaneous puncture repair show great promise to mitigate potentially catastrophic damage from events such as micrometeoroid penetration. Effective self-repair requires these materials to heal instantaneously following projectile penetration while retaining structural integrity. Poly(ethylene-co-methacrylic acid) (EMMA), also known as Surlyn is an ionomer-based copolymer that undergoes puncture reversal (self-healing) following high impact puncture at high velocities. However EMMA is not a structural engineering polymer, and will not meet the demands of aerospace applications requiring self-healing engineering materials. Current efforts to identify candidate self-healing polymer materials for structural engineering systems are reported. Rheology, high speed thermography, and high speed video for self-healing semi-crystalline and amorphous polymers will be reported.

Gordon, Keith L.↗
DOE OSTI2023

LANL Test Engineering’s Structural Dynamics Research and Development Efforts [Slides]

LANL's priority roles are serving as a nuclear weapons design agency and a nuclear weapons production agency; addressing nuclear threats; and performing national security science, technology, and engineering. LANL’s Test Engineering organization serves the national mission of maintaining a strategic nuclear deterrent by providing high-quality, empirical evidence through the execution and assessment of weapons system and component testing. Shock and vibration environmental testing provides one key piece of evidence for evaluation and qualification of these systems and components in the service environments incurred during a lifetime in the stockpile. LANL’s Test Engineering group continuously pursues research and development in structural dynamics to improve shock and vibration testing capabilities, processes, and analysis techniques to increase the fidelity of service environment recreations in laboratory testing settings. This talk will highlight several ongoing projects to represent these R&D efforts.

42 ENGINEERING↗
NASA NTRS1983

NASA LeRC/Akron University Graduate Cooperative Fellowship Program and Graduate Student Researchers Program

On June 1, 1980, the University of Akron and the NASA Lewis Research Center (LERC) established a Graduate Cooperative Fellowship Program in the specialized areas of Engine Structural Analysis and Dynamics, Computational Mechanics, Mechanics of Composite Materials, and Structural Optimization, in order to promote and develop requisite technologies in these areas of engine technology. The objectives of this program are consistent with those of the NASA Engine Structure Program in which graduate students of the University of Akron participate by conducting research at Lewis. This report is the second on this grant and summarizes the second and third year research effort, which includes the participation of five graduate students where each student selects one of the above areas as his special field of interest. Each student is required to spend 30 percent of his educational training time at the NASA Lewis Research Center and the balance at the University of Akron. His course work is judiciously selected and tailored to prepare him for research work in his field of interest. A research topic is selected for each student while in residence at the NASA Lewis Research Center, which is also approved by the faculty of the University of Akron as his thesis topic for a Master's and/or a Ph.D. degree.

Fertis, D. G.↗
NASA NTRS2011

High-Temperature Smart Structures for Engine Noise Reduction and Performance Enhancement

One of key NASA goals is to develop and integrate noise reduction technology to enable unrestricted air transportation service to all communities. One of the technical priorities of this activity has been to account for and reduce noise via propulsion/airframe interactions, identifying advanced concepts to be integrated with the airframe to mitigate these noise-producing mechanisms. An adaptive geometry chevron using embedded smart structures technology offers the possibility of maximizing engine performance while retaining and possibly enhancing the favorable noise characteristics of current designs. New high-temperature shape memory alloy (HTSMA) materials technology enables the devices to operate in both low-temperature (fan) and high-temperature (core) exhaust flows. Chevron-equipped engines have demonstrated reduced noise in testing and operational use. It is desirable to have the noise benefits of chevrons in takeoff/landing conditions, but have them deployed into a minimum drag position for cruise flight. The central feature of the innovation was building on rapidly maturing HTSMA technology to implement a next-generation aircraft noise mitigation system centered on adaptive chevron flow control surfaces. In general, SMA-actuated devices have the potential to enhance the demonstrated noise reduction effectiveness of chevron systems while eliminating the associated performance penalty. The use of structurally integrated smart devices will minimize the mechanical and subsystem complexity of this implementation. The central innovations of the effort entail the modification of prior chevron designs to include a small cut that relaxes structural stiffness without compromising the desired flow characteristics over the surface; the reorientation of SMA actuation devices to apply forces to deflect the chevron tip, exploiting this relaxed stiffness; and the use of high-temperature SMA (HTSMA) materials to enable operation in the demanding core chevron environment. The overall conclusion of these design studies was that the cut chevron concept is a critical enabling step in bringing the variable geometry core chevron within reach. The presence of the cut may be aerodynamically undesirable in some respects, but it is present only when the chevron is not immersed in the core jet exhaust. When deployed, the gap closes as the chevron tip enters the high-speed, high-temperature core stream. Aeroacoustic testing and flow visualization support the contention that this cut is inconsequential to chevron performance.

Quackenbush, Todd R.↗
DOE OSTI2020

Structure-Guided Engineering of a Scoulerine 9-O-Methyltransferase Enables the Biosynthesis of Tetrahydropalmatrubine and Tetrahydropalmatine in Yeast

Benzylisoquinoline alkaloids (BIAs) are an important class of plant natural products with diverse pharmacological properties. Microbial platforms can produce BIAs through heterologous biosynthesis more efficiently than native plant hosts and allow for the generation of currently inaccessible BIA biosynthetic intermediates and unnatural derivatives. However, much remains unknown regarding the structures, substrate scopes, and mechanisms of many of the enzymes involved in BIA biosynthesis, which hampers efforts toward engineering these enzymes to produce alternative products or act in non-native biosynthetic contexts. In this paper, we present multiple crystal structures of two scoulerine 9- O -methyltransferase (S9OMT) variants from Thalictrum flavum which catalyze an essential step in the biosynthesis of berberine. The crystal structures revealed the structural basis for substrate and cofactor recognition by Tf S9OMT and provide further insight into the structure and function of S9OMTs. A structural comparison of the Tf S9OMT and T. flavum norcoclaurine 6OMT ( Tf 6OMT) crystal structures identified important residues for enzyme regiospecificity, which were confirmed via mutagenesis and in vitro assays. Several Tf S9OMT mutants with expanded substrate scopes toward various 1-benzylisoquinoline substrates were generated. The rationally engineered Tf S9OMT mutants with altered regiospecificity were tested in a yeast-based scoulerine production platform and enabled de novo production of tetrahydropalmatrubine and tetrahydropalmatine.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1990

Small band gap superlattices as intrinsic long wavelength infrared detector materials

Intrinsic long wavelength (lambda greater than or equal to 10 microns) infrared (IR) detectors are currently made from the alloy (Hg, Cd)Te. There is one parameter, the alloy composition, which can be varied to control the properties of this material. The parameter is chosen to set the band gap (cut-off wavelength). The (Hg, Cd)Te alloy has the zincblend crystal structure. Consequently, the electron and light-hole effective masses are essentially inversely proportional to the band gap. As a result, the electron and light-hole effective masses are very small (M sub(exp asterisk)/M sub o approx. M sub Ih/M sub o approx. less than 0.01) whereas the heavy-hole effective mass is ordinary size (M sub hh(exp asterisk)/M sub o approx. 0.4) for the alloy compositions required for intrinsic long wavelength IR detection. This combination of effective masses leads to rather easy tunneling and relatively large Auger transition rates. These are undesirable characteristics, which must be designed around, of an IR detector material. They follow directly from the fact that (Hg, Cd)Te has the zincblend crystal structure and a small band gap. In small band gap superlattices, such as HgTe/CdTe, In(As, Sb)/InSb and InAs/(Ga,In)Sb, the band gap is determined by the superlattice layer thicknesses as well as by the alloy composition (for superlattices containing an alloy). The effective masses are not directly related to the band gap and can be separately varied. In addition, both strain and quantum confinement can be used to split the light-hole band away from the valence band maximum. These band structure engineering options can be used to reduce tunneling probabilities and Auger transition rates compared with a small band gap zincblend structure material. Researchers discuss the different band structure engineering options for the various classes of small band gap superlattices.

Smith, Darryl L.↗
NASA NTRS1987

Semiconductor alloys - Structural property engineering

Semiconductor alloys have been used for years to tune band gaps and average bond lengths to specific applications. Other selection criteria for alloy composition, and a growth technique designed to modify their structural properties, are presently considered. The alloys Zn(1-y)Cd(y)Te and CdSe(y)Te(1-y) are treated as examples.

Sher, A.↗
DOE OSTI2019

Crystal Structure of the Ergothioneine Sulfoxide Synthase from Candidatus Chloracidobacterium thermophilum and Structure-Guided Engineering To Modulate Its Substrate Selectivity

Ergothioneine is a thiohistidine derivative with potential benefits on many aging-related diseases. The central step of aerobic ergothioneine biosynthesis is the oxidative C–S bond formation reaction catalyzed by mononuclear nonheme iron sulfoxide synthases (EgtB and Egt1). Thus far, only the Mycobacterium thermoresistibile EgtB (EgtB Mth ) crystal structure is available, while the structural information for the more industrially attractive Egt1 enzyme is not. In this paper, we reported the crystal structure of the ergothioneine sulfoxide synthase (EgtB Cth ) from Candidatus Chloracidobacterium thermophilum . EgtB Cth has both EgtB- and Egt1-type of activities. Guided by the structural information, we conducted Rosetta Enzyme Design calculations, and we biochemically demonstrated that EgtB Cth can be engineered more toward Egt1-type of activity. This study provides information regarding the factors governing the substrate selectivity in Egt1- and EgtB-catalysis and lays the groundwork for future sulfoxide synthase engineering toward the development of an effective ergothioneine process through a synthetic biology approach.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Lignin structure and its engineering

Research on lignin structure and its engineering are inextricably and bidirectionally linked. Perturbations of genes on the lignin biosynthetic pathway may end in striking compositional and structural changes that in turn indicate novel methods for altering lignin and even ‘designing’ the polymer to enhance its value or with a view toward its simpler removal from the cell wall polysaccharides. Basic structural studies on various native lignins increasingly refine our knowledge of lignin structure, and examining lignins in different species reveals the extent to which evolution and natural variation have resulted in the incorporation of ‘non-traditional’ phenolic monomers, including phenolics from beyond the monolignol biosynthetic pathway. As a result, the very definition of lignin continues to be expanded and refined.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1981

Structures, performance, benefit, cost study

Aircraft engine structures were studied to identify the advanced structural technologies that would provide the most benefits to future aircraft operations. A series of studies identified engine systems with the greatest potential for improvements. Based on these studies, six advanced generic structural concepts were selected and conceptually designed. The benefits of each concept were quantitatively assessed in terms of thrust specific fuel consumption, weight, cost, maintenance cost, fuel burned and direct operating cost plus interest. The probability of success of each concept was also determined. The concepts were ranked and the three most promising were selected for further study which consisted of identifying and comprehensively outlining the advanced technologies required to develop these concepts for aircraft engine application. Analytic, fabrication, and test technology developments are required. The technology programs outlined emphasize the need to provide basic, fundamental understanding of technology to obtain the benefit goals.

Feder, E.↗
NASA NTRS2014

Dorothy Jorgensen - Co-Op Tour Summary

NASA is a household name in this day and age, known commonly as America's government-run powerhouse of innovation and space exploration. It is a common dream for students to be a part of NASA's workforce, but I did not realize that it was my dream until I found that I could not imagine working anywhere else. From August to December, I had the privilege of a co-op tour with NASA at the Johnson Space Center. The National Aeronautics and Space Administration (NASA) first formed in the early hysteria of the Cold War, and in its early days it received enormous funding and political support. It was America's response to the Russian Sputnik, which was a not only a stark symbol of what was suddenly possible, but also of how far behind the United States had fallen in the race for technology. The political atmosphere in the world has since changed, but NASA's drive to push the boundaries of the impossible has not faded: NASA's primary mission has been exploration for the betterment of mankind, and it works towards that mission to this day. The specific NASA site that I worked in was by a coast near Houston, TX, at the Johnson Space Center (Figure 1). I was led on my first day of work to a building dedicated to Structural Engineering (Building 13), which was where I would be spending most of my time in the months to come. It was here that I had my desk and cubicle, and would later do the bulk of my computer modeling and theoretical planning. Later that day we traveled to the Vibrations and Acoustics Test Facility (Building 49), and here I was shown the parts we would use for our technical project and the locations we would work in. I worked in the Loads and Dynamics Branch of the Structural Engineering Division, in the Engineering Directorate.

Jorgensen, Dorothy↗
NASA NTRS2017

Educational Projects in Unmanned Aerial Systems at the NASA Ames Research Center

Unmanned aerial systems (UAS), autonomy and robotics technology have been fertile ground for developing a wide variety of interdisciplinary student learning opportunities. In this talk, several projects will be described that leverage small fixed-wing UAS that have been modified to carry science payloads. These aircraft provide a unique hands-on experience for a wide range of students from college juniors to graduate students pursuing degrees in electrical engineering, aeronautical engineering, mechanical engineering, applied mathematics, physics, structural engineering and other majors. By combining rapid prototyping, design reuse and open-source philosophies, a sustainable educational program has been organized structured as full-time internships during the summer, part-time internships during the school year, short details for military cadets, and paid positions. As part of this program, every summer one or more UAS is developed from concept through design, build and test phases using the tools and facilities at the NASA Ames Research Center, ultimately obtaining statements of airworthiness and flight release from the Agency before test flights are performed. In 2016 and 2017 student projects focused on the theme of 3D printed modular airframes that may be optimized for a given mission and payload. Now in its fifth year this program has served over 35 students, and has provided a rich learning experience as they learn to rapidly develop new aircraft concepts in a highly regulated environment, on systems that will support principal investigators at university, NASA, and other US federal agencies.

UA↗
DOE OSTI2018

Structure-Based Engineering of Irreversible Inhibitors against Histone Lysine Demethylase KDM5A

The active sites of hundreds of human α-ketoglutarate (αKG) and Fe(II)-dependent dioxygenases are exceedingly well preserved, which challenges the design of selective inhibitors. In this work we identified a noncatalytic cysteine (Cys481 in KDM5A) near the active sites of KDM5 histone H3 lysine 4 demethylases, which is absent in other histone demethylase families, that could be explored for interaction with the cysteine-reactive electrophile acrylamide. We synthesized analogs of a thienopyridine-based inhibitor chemotype, namely, 2-((3-aminophenyl)(2-(piperidin-1-yl)ethoxy)methyl)thieno[3,2-b]- pyridine-7-carboxylic acid (N70) and a derivative containing a (dimethylamino)but-2-enamido)phenyl moiety (N71) designed to form a covalent interaction with Cys481. We characterized the inhibitory and binding activities against KDM5A and determined the cocrystal structures of the catalytic domain of KDM5A in complex with N70 and N71. Whereas the noncovalent inhibitor N70 displayed αKG-competitive inhibition that could be reversed after dialysis, inhibition by N71 was dependent on enzyme concentration and persisted even after dialysis, consistent with covalent modification.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗