SEARCH · Engineering Papers

Results for “Support Activities”

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.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 541 records · Page 30

All sources NASA NTRS DOE OSTI

DOE OSTI2022

Scaffolding matrix with internal nanoparticles

A battery electrode composition is provided comprising composite particles, with each composite particle comprising active material and a scaffolding matrix. The active material is provided to store and release ions during battery operation. For certain active materials of interest, the storing and releasing of the ions causes a substantial change in volume of the active material. The scaffolding matrix is provided as a porous, electrically-conductive scaffolding matrix within which the active material is disposed. In this way, the scaffolding matrix structurally supports the active material, electrically interconnects the active material, and accommodates the changes in volume of the active material.

Yushin, Gleb↗

DOE OSTI2022

Scaffolding matrix with internal nanoparticles

25 ENERGY STORAGE↗

DOE OSTI2024

Scaffolding matrix with internal nanoparticles

Yushin, Gleb↗

NASA NTRS1995

Modeling of a possible conformational change associated with the catalytic mechanism in the hammerhead ribozyme

Here we describe a possible model of the cleavage mechanism in the hammerhead ribozyme. In this model, the 2' hydroxyl of C17 is moved into an appropriate orientation for an in-line attack on the G1.1 phosphate through a change in its sugar pucker from C3' endo to C2' endo. This conformational change in the active site is caused by a change in the uridine turn placing the N2 and N3 atoms of G5 of the conserved core in hydrogen bonding geometry with the N3 and N2 atoms on the conserved G16.2 residue. The observed conformational change in the uridine turn suggests an explanation for the conservation of G5. In the crystal structure of H.M. Pley et al., Nature 372, 68-74 (1994), G5 is situated 5.3A away from G16.2. However, the uridine turn is sufficiently flexible to allow this conformational change with relatively modest changes in the backbone torsion angles (average change of 14.2 degrees). Two magnesium ions were modeled into the active site with positions analogous to those described in the functionally similar Klenow fragment 3'-5' exonuclease (L.S. Beese and T.A. Steitz, EMBO J. 10, 25-33 (1991)), the Group I intron (T.A. Steitz and J.A. Steitz, P.N.A.S. U.S.A. 90, 6498-6502 (1993); R.F. Setlik et al., J. Biomol. Str. Dyn. 10, 945-972 (1993)) and other phosphotransferases. Comparison of this model with one in which the uridine turn conformation was not changed showed that although the changes in the C17 sugar pucker could be modeled, insufficient space existed for the magnesium ions in the active site.

Non-NASA Center↗

DOE OSTI2021

Active Sites in a Heterogeneous Organometallic Catalyst for the Polymerization of Ethylene

Heterogeneous derivatives of catalysts developed by Ziegler and Natta are important for the industrial production of polyolefin plastics. However, the interaction between precatalysts, alkylaluminum activators, and oxide supports to form catalytically active materials is poorly understood. This is in contrast to homogeneous or well-defined heterogeneous catalysts that 20 contain resolved molecular structures that relate to activity and selectivity in polymerization reactions. This study describes the reactivity of triisobutylaluminum with high surface area aluminum oxide and a zirconocene precatalyst. Triisobutylaluminum reacts with the zirconocene precatalyst to form hydrides and passivates –OH sites on the alumina surface. The combination of passivated alumina and zirconium hydrides formed in this mixture generate ion-pairs that 25 polymerize ethylene.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2020

Surface oxygenation of multicomponent nanoparticles toward active and stable oxidation catalysts

Abstract The need for active and stable oxidation catalysts is driven by the demands in production of valuable chemicals, remediation of hydrocarbon pollutants and energy sustainability. Traditional approaches focus on oxygen-activating oxides as support which provides the oxygen activation at the catalyst-support peripheral interface. Here we report a new approach to oxidation catalysts for total oxidation of hydrocarbons (e.g., propane) by surface oxygenation of platinum (Pt)-alloyed multicomponent nanoparticles (e.g., platinum-nickel cobalt (Pt–NiCo)). The in-situ/operando time-resolved studies, including high-energy synchrotron X-ray diffraction and diffuse reflectance infrared Fourier transform spectroscopy, demonstrate the formation of oxygenated Pt–NiOCoO surface layer and disordered ternary alloy core. The results reveal largely-irregular oscillatory kinetics associated with the dynamic lattice expansion/shrinking, ordering/disordering, and formation of surface-oxygenated sites and intermediates. The catalytic synergy is responsible for reduction of the oxidation temperature by ~100 °C and the high stability under 800 °C hydrothermal aging in comparison with Pt, and may represent a paradigm shift in the design of self-supported catalysts.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2024

Structural basis of transcription: RNA polymerase II substrate binding and metal coordination using a free-electron laser

Catalysis and translocation of multisubunit DNA-directed RNA polymerases underlie all cellular mRNA synthesis. RNA polymerase II (Pol II) synthesizes eukaryotic pre-mRNAs from a DNA template strand buried in its active site. Structural details of catalysis at near-atomic resolution and precise arrangement of key active site components have been elusive. Here, we present the free-electron laser (FEL) structures of a matched ATP-bound Pol II and the hyperactive Rpb1 T834P bridge helix (BH) mutant at the highest resolution to date. The radiation-damage-free FEL structures reveal the full active site interaction network, including the trigger loop (TL) in the closed conformation, bonafide occupancy of both site A and B Mg 2+ , and, more importantly, a putative third (site C) Mg 2+ analogous to that described for some DNA polymerases but not observed previously for cellular RNA polymerases. Molecular dynamics (MD) simulations of the structures indicate that the third Mg 2+ is coordinated and stabilized at its observed position. TL residues provide half of the substrate binding pocket while multiple TL/BH interactions induce conformational changes that could allow translocation upon substrate hydrolysis. Consistent with TL/BH communication, a FEL structure and MD simulations of the T834P mutant reveal rearrangement of some active site interactions supporting potential plasticity in active site function and long-distance effects on both the width of the central channel and TL conformation, likely underlying its increased elongation rate at the expense of fidelity.

Science & Technology - Other Topics↗

NASA NTRS1973

Digital processing of Mariner 9 television data.

The digital image processing performed by the Image Processing Laboratory (IPL) at JPL in support of the Mariner 9 mission is summarized. The support is divided into the general categories of image decalibration (the removal of photometric and geometric distortions from returned imagery), computer cartographic projections in support of mapping activities, and adaptive experimenter support (flexible support to provide qualitative digital enhancements and quantitative data reduction of returned imagery). Among the tasks performed were the production of maximum discriminability versions of several hundred frames to support generation of a geodetic control net for Mars, and special enhancements supporting analysis of Phobos and Deimos images.

Green, W. B.↗

NASA NTRS1985

NASA Lewis Research Center low-gravity fluid management technology program

A history of the Lewis Research Center in space fluid management technology program is presented. Current programs which include numerical modeling of fluid systems, heat exchanger/radiator concept studies, and the design of the Cryogenic Fluid Management Facility are discussed. Recent analytical and experimental activities performed to support the Shuttle/Centaur development activity are highlighted.

Aydelott, J. C.↗

NASA NTRS1985

NASA Lewis Research Center low-gravity fluid management technology program

Aydelott, J. C.↗

DOE OSTI2023

Modeling plasma-induced surface charge effects on CO 2 activation by single atom catalysts supported on reducible and irreducible metal oxides

Abstract The accumulation of negative surface charge on catalytic surfaces in the presence of low-temperature plasma (LTP) could influence catalytic performance. However, it is difficult to disentangle the role of surface charging and other LTP catalytic effects in experiment. Herein, we use density functional theory (DFT) modeling to understand the effect of plasma-induced surface charging on CO 2 activation by atomically dispersed single atom (SA) catalysts on both reducible and irreducible metal oxide supports. We model CO 2 adsorption strength and CO 2 dissociation barriers for Co 1 , Ni 1 , Cu 1 , Rh 1 , Pd 1 , and Ag 1 SAs on both reducible and irreducible supports, namely, CeO 2 (100), TiO 2 (101), and γ -Al 2 O 3 (110), to elucidate trends. We find that accumulated surface charge on the SA increases the CO 2 adsorption strength and decreases the CO 2 dissociation barrier for all studied SA/support combinations. For both charged and uncharged (neutral) systems, SAs on the reducible CeO 2 (100) support generally adsorb CO 2 more weakly compared to when on irreducible supports like γ -Al 2 O 3 (110). SAs on γ -Al 2 O 3 (110) typically have larger barriers for CO 2 dissociation for both charged and uncharged systems compared to TiO 2 (101) and CeO 2 (100). The magnitude of surface charging effects on CO 2 binding energies and dissociation barriers depends sensitively on both the SA and the support. In some cases, the CO 2 activation trends qualitatively change between neutral and charged systems for a fixed SA across different supports. This DFT modeling study demonstrates that surface charging should be considered in strong electric fields because it can have a large effect on molecule adsorption and bond-breaking on catalytic surfaces.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

NASA NTRSDate not supplied

Space-based Sensor for Extreme Fire Weather Events

Catastrophic bushfires are becoming increasingly prevalent as climate change advances. Impacts extend beyond national borders. Multinational efforts can inform new science and management practices. Space-based sensors and integrated data facilities will play an important role. This paper describes a collaborative project between a consortium of Australian universities and NASA Centers to develop and implement a small satellite platform comprising highly integrated thermal and lightning sensors coupled with AI-based edge computing to help predict, detect, and track bushfires, supporting mitigation activities. This will fill an important capability gap since Australia does not currently have any sovereign Earth observation satellites. This program is enabled by and builds on Australia-NASA collaboration and will also support fire science and management activities in the broader global context.

wildfire↗

NASA NTRS1978

Shuttle crew station astronaut interfaces

The current shuttle orbiter configuration and its crew module and payload bay accomodations for work and off duty activities are described. The capability of the remote manipulator system and provisions to support extravehicular activities are examined with emphasis on flight crew activities for orbital flight tests and for early operational space transportation system flights. Facilities used to verify crew interfaces are also described.

Franklin, G. C.↗

NASA NTRS1989

Active vibration control for flexible rotor by optimal direct-output feedback control

Experimental research tests were performed to actively control the rotor vibrations of a flexible rotor mounted on flexible bearing supports. The active control method used in the tests is called optimal direct-output feedback control. This method uses four electrodynamic actuators to apply control forces directly to the bearing housings in order to achieve effective vibration control of the rotor. The force actuators are controlled by an analog controller that accepts rotor displacement as input. The controller is programmed with experimentally determined feedback coefficients; the output is a control signal to the force actuators. The tests showed that this active control method reduced the rotor resonance peaks due to unbalance from approximately 250 micrometers down to approximately 25 micrometers (essentially runout level). The tests were conducted over a speed range from 0 to 10,000 rpm; the rotor system had nine critical speeds within this speed range. The method was effective in significantly reducing the rotor vibration for all of the vibration modes and critical speeds.

Nonami, Kenzou↗

NASA NTRS1989

Active vibration control for flexible rotor by optimal direct-output feedback control

Experimental research tests were performed to actively control the rotor vibrations of a flexible rotor mounted on flexible bearing supports. The active control method used in the tests is called optimal direct-output feedback control. This method uses four electrodynamic actuators to apply control forces directly to the bearing housings in order to achieve effective vibration control of the rotor. The force actuators are controlled by an analog controller that accepts rotor displacement as input. The controller is programmed with experimentally determined feedback coefficients; the output is a control signal to the force actuators. The tests showed that this active control method reduced the rotor resonance peaks due to unbalance from approximately 250 microns down to approximately 25 microns (essentially runout level). The tests were conducted over a speed range from 0 to 10,000 rpm; the rotor system had nine critical speeds within this speed range. The method was effective in significantly reducing the rotor vibration for all of the vibration modes and critical speeds.

Nonami, K.↗

NASA NTRS2005

STS-114: Mission Status Briefing

Phil Engelauf, STS-114 Mission Operations Representative; Mark Ferring, Lead ISS Flight Director; Cindy Begley, Lead Spacewalk Officer for the Mission were present. Phil reported that the vehicle continues to operate very cleanly, no system anomalies or issues, crew keeping up with the timelines, and small minor and major EVA activities went extremely well. He recapped previous day's activities such as: nitrogen transfer to the Station, and storing water and transferring it to the Space Station. Mark noted Mission Specialists Steven Robinson and Souichi Noguchi's superb job doing EVA. Cindy gave a technical detail of the CMG1 remove and replace activities with supporting video clips. News media focused their questions on technical details of flight activities and safety.

Source record↗

NASA NTRS1973

Study of CO2 sorbents for extravehicular activity

Portable life support equipment was studied for meeting the requirements of extravehicular activities. Previous studies indicate that the most promising method for performing the CO2 removal function removal function were metallic oxides and/or metallic hydroxides. Mgo, Ag2, and Zno metallic oxides and Mg(OH)2 and Zn(OH)2 metallic hydroxides were studied, by measuring sorption and regeneration properties of each material. The hydroxides of Mg and Zn were not regenerable and the zinc oxide compounds showed no stable form. A silver oxide formulation was developed which rapidly absorbs approximately 95% of its 0.19 Kg CO2 Kg oxide and has shown no sorption or structural degeneration through 22 regenerations. It is recommended that the basic formula be further developed and tested in large-scale beds under simulated conditions.

Colombo, G. V.↗

NASA NTRS1996

An Open Computing Infrastructure that Facilitates Integrated Product and Process Development from a Decision-Based Perspective

Computer applications for design have evolved rapidly over the past several decades, and significant payoffs are being achieved by organizations through reductions in design cycle times. These applications are overwhelmed by the requirements imposed during complex, open engineering systems design. Organizations are faced with a number of different methodologies, numerous legacy disciplinary tools, and a very large amount of data. Yet they are also faced with few interdisciplinary tools for design collaboration or methods for achieving the revolutionary product designs required to maintain a competitive advantage in the future. These organizations are looking for a software infrastructure that integrates current corporate design practices with newer simulation and solution techniques. Such an infrastructure must be robust to changes in both corporate needs and enabling technologies. In addition, this infrastructure must be user-friendly, modular and scalable. This need is the motivation for the research described in this dissertation. The research is focused on the development of an open computing infrastructure that facilitates product and process design. In addition, this research explicitly deals with human interactions during design through a model that focuses on the role of a designer as that of decision-maker. The research perspective here is taken from that of design as a discipline with a focus on Decision-Based Design, Theory of Languages, Information Science, and Integration Technology. Given this background, a Model of IPPD is developed and implemented along the lines of a traditional experimental procedure: with the steps of establishing context, formalizing a theory, building an apparatus, conducting an experiment, reviewing results, and providing recommendations. Based on this Model, Design Processes and Specification can be explored in a structured and implementable architecture. An architecture for exploring design called DREAMS (Developing Robust Engineering Analysis Models and Specifications) has been developed which supports the activities of both meta-design and actual design execution. This is accomplished through a systematic process which is comprised of the stages of Formulation, Translation, and Evaluation. During this process, elements from a Design Specification are integrated into Design Processes. In addition, a software infrastructure was developed and is called IMAGE (Intelligent Multidisciplinary Aircraft Generation Environment). This represents a virtual apparatus in the Design Experiment conducted in this research. IMAGE is an innovative architecture because it explicitly supports design-related activities. This is accomplished through a GUI driven and Agent-based implementation of DREAMS. A HSCT design has been adopted from the Framework for Interdisciplinary Design Optimization (FIDO) and is implemented in IMAGE. This problem shows how Design Processes and Specification interact in a design system. In addition, the problem utilizes two different solution models concurrently: optimal and satisfying. The satisfying model allows for more design flexibility and allows a designer to maintain design freedom. As a result of following this experimental procedure, this infrastructure is an open system that it is robust to changes in both corporate needs and computer technologies. The development of this infrastructure leads to a number of significant intellectual contributions: 1) A new approach to implementing IPPD with the aid of a computer; 2) A formal Design Experiment; 3) A combined Process and Specification architecture that is language-based; 4) An infrastructure for exploring design; 5) An integration strategy for implementing computer resources; and 6) A seamless modeling language. The need for these contributions is emphasized by the demand by industry and government agencies for the development of these technologies.

Hale, Mark A.↗