Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “BASIC INTERACTIONS”

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.

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

At least 703 records · Page 39
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

The electromagnetic field for an open magnetosphere

The boundary-layer-dominated models of the earth EM field developed by Heikkila (1975, 1978, 1982, and 1983) and Heikkila et al. (1979) to account for deficiencies in the electric-field descriptions of quasi-steady-state magnetic-field-reconnection models (such as that of Cowley, 1980) are characterized, reviewing the arguments and indicating the most important implications. The mechanisms of boundary-layer formation and field direction reversal are explained and illustrated with diagrams, and it is inferred that boundary-layer phenomena rather than magnetic reconnection may be the cause of large-scale magnetospheric circulation, convection, plasma-sheet formation and sunward convection, and auroras, the boundary layer acting basically as a viscous process mediating solar-wind/magnetosphere interactions.

Heikkila, W. J.↗
NASA NTRS1988

Preliminary design study of hydrogen and ammonia resistojets for prime and auxiliary thrusters

Designs of high performance resistojets for primary and auxiliary propulsion are described.Thruster power for the primary propulsion application was in the 2 to 3 kW range while auxiliary propulsion power per thruster was 0.15 to 0.25 kW. Propellants considered were hydrogen and ammonia. The report described design techniques used to forecast the temperature and energy flux distributions using mathematical modeling by personal microcomputer. BASIC language is used throughout to give the designer rapid interaction and control. Both designs integrate compact first stage coils with concentric tubular heaters. The hybrid heater design allows better thruster power matching with the spacecraft power bus. Projected specific impulse levels were 760 to 830 s for hydrogen and 380 to 410 s for ammonia.

Page, Russell J.↗
NASA NTRS1989

Techniques for optimizing human-machine information transfer related to real-time interactive display systems

In recent years the needs of ground-based researcher-analysts to access real-time engineering data in the form of processed information has expanded rapidly. Fortunately, the capacity to deliver that information has also expanded. The development of advanced display systems is essential to the success of a research test activity. Those developed at the National Aeronautics and Space Administration (NASA), Western Aeronautical Test Range (WATR), range from simple alphanumerics to interactive mapping and graphics. These unique display systems are designed not only to meet basic information display requirements of the user, but also to take advantage of techniques for optimizing information display. Future ground-based display systems will rely heavily not only on new technologies, but also on interaction with the human user and the associated productivity with that interaction. The psychological abilities and limitations of the user will become even more important in defining the difference between a usable and a useful display system. This paper reviews the requirements for development of real-time displays; the psychological aspects of design such as the layout, color selection, real-time response rate, and interactivity of displays; and an analysis of some existing WATR displays.

Granaas, Michael M.↗
NASA NTRS1993

Physical insight into the simultaneous optimization of structure and control

Recent trends in spacecraft design which yield larger structures with more stringent performance requirements place many flexible modes of the structure within the bandwidth of active controllers. The resulting complications to the spacecraft design make it highly desirable to understand the impact of structural changes on an optimally controlled structure. This work uses low structural models with optimal H(sub 2) and H(sub infinity) controllers to develop some basic insight into this problem. This insight concentrates on several basic approaches to improving controlled performance and how these approaches interact in determining the optimal designs. A numerical example is presented to demonstrate how this insight can be generalized to more complex problems.

Jacques, Robert N.↗
NASA NTRS1992

Analysis of composite structures with delaminations under combined bending and compression

A methodology had been developed for strength prediction of composite structures with delaminations under combined bending and compression loads. The methodology is an extension of the delamination analysis method developed under the USAF/Boeing/Northrop 'Damage Tolerance of Composites' program. Delamination buckling and strain energy release rate analyses are used as basic tools in the strength prediction. In addition, failure mode interaction and structural configuration effects are considered. The influence of fasteners on the strength of a delaminated structure is incorporated to evaluate assembly-caused delaminations. The capabilities and limitations of the analysis method are shown by correlating the analytical results with the existing experimental data. The failure load, failure mode and failure sequence of a structure containing delaminations are predicted and the analytical results are compared with test data.

Kan, Han-Pin↗
NASA NTRS2009

Development of a Large Field-of-View PIV System for Rotorcraft Testing in the 14- x 22-Foot Subsonic Tunnel

A Large Field-of-View Particle Image Velocimetry (LFPIV) system has been developed for rotor wake diagnostics in the 14-by 22-Foot Subsonic Tunnel. The system has been used to measure three components of velocity in a plane as large as 1.524 meters by 0.914 meters in both forward flight and hover tests. Overall, the system performance has exceeded design expectations in terms of accuracy and efficiency. Measurements synchronized with the rotor position during forward flight and hover tests have shown that the system is able to capture the complex interaction of the body and rotor wakes as well as basic details of the blade tip vortex at several wake ages. Measurements obtained with traditional techniques such as multi-hole pressure probes, Laser Doppler Velocimetry (LDV), and 2D Particle Image Velocimetry (PIV) show good agreement with LFPIV measurements.

Jenkins, Luther N.↗
NASA NTRS2013

Crew Roles and Interactions in Scientific Space Exploration

Future piloted space exploration missions will focus more on science than engineering, a change which will challenge existing concepts for flight crew tasking and demand that participants with contrasting skills, values, and backgrounds learn to cooperate as equals. In terrestrial space flight analogs such as Desert Research And Technology Studies, engineers, pilots, and scientists can practice working together, taking advantage of the full breadth of all team members training to produce harmonious, effective missions that maximize the time and attention the crew can devote to science. This paper presents, in a format usable as a reference by participants in the field, a successfully tested crew interaction model for such missions. The model builds upon the basic framework of a scientific field expedition by adding proven concepts from aviation and human spaceflight, including expeditionary behavior and cockpit resource management, cooperative crew tasking and adaptive leadership and followership, formal techniques for radio communication, and increased attention to operational considerations. The crews of future spaceflight analogs can use this model to demonstrate effective techniques, learn from each other, develop positive working relationships, and make their expeditions more successful, even if they have limited time to train together beforehand. This model can also inform the preparation and execution of actual future spaceflights.

Love, Stanley G.↗
DOE OSTI2022

Ion-imbibed membranes based on proton conducting aromatic polyether type copolymers and their application in redox flow batteries

The present invention relates to a class of polymer ion imbibed membranes for electrolyte flow batteries. The membranes are a conducting aromatic polyether type copolymer bearing nitrogen heterocycles groups, especially pyridine type. While the membranes can be used in acid, basic, and neutral electrolytes, the nitrogen heterocycles in the membrane interact with acid in the electrolyte to form a proton transport network, so as to keep the proton transport performance of the membrane. The membrane has excellent mechanical stability and thermostability as well as tunable porosity.

Paloumbis, George↗
DOE OSTI2013

The JRC-ITU approach to the safety of advanced nuclear fuel cycles

The JRC-ITU safety studies of advanced fuels and cycles adopt two main axes. First the full exploitation of still available and highly relevant knowledge and samples from past fuel preparation and irradiation campaigns (complementing the limited number of ongoing programmes). Secondly, the shift of focus from simple property measurement towards the understanding of basic mechanisms determining property evolution and behaviour of fuel compounds during normal, off-normal and accident conditions. The final objective of the second axis is the determination of predictive tools applicable to systems and conditions different from those from which they were derived. State of the art experimental facilities, extensive networks of partnerships and collaboration with other organizations worldwide, and a developing programme for training and education are essential in this approach. This strategy has been implemented through various programs and projects. The SUPERFACT programme constitutes the main body of existing knowledge on the behavior in-pile of MOX fuel containing minor actinides. It encompassed all steps of a closed fuel cycle. Another international project investigating the safety of a closed cycle is METAPHIX. In this case a U-Pu19-Zr10 metal alloy containing Np, Am and Cm constitutes the fuel. 9 test pins have been prepared and irradiated. In addition to the PIE (Post Irradiation Examination), pyrometallurgical separation of the irradiated fuel has been performed, to demonstrate all the steps of a multiple recycling closed cycle and characterize their safety relevant aspects. Basic studies like thermodynamic fuel properties, fuel-cladding-coolant interactions have also been carried out at JRC-ITU.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
NASA NTRS1977

Solar-terrestrial interactions

The effects of solar radiation on man's environment are discussed. It is solar radiation that is the basic energy source driving the circulations of the earth's atmosphere and oceans. Solar radiation is responsible for the ionization of the earth's upper atmosphere to form the ionosphere, which is important to our understanding of the magnetosphere and its interaction with the solar wind. The solar wind, which is the continuous (but not steady) flow of the sun's coronal plasma and magnetic field into interplanetary space, plays both an active and passive role in its interaction with the earth's environment.

Source record↗
DOE OSTI2022

Proteomic Profiling of Intra-Islet Features Reveals Substructure-Specific Protein Signatures

Despite their diminutive size, islets of Langerhans play a large role in maintaining systemic energy balance in the body. New technologies have enabled us to go from studying the whole pancreas, to isolated whole islets, to partial islet sections, and now to islet substructures isolated from within the islet. Using a microfluidic nanodroplet-based proteomics platform coupled with laser capture microdissection (LCM), we present an in-depth investigation of protein profiles specific to regions within the islet. These regions studied include the vascular tissue containing interface boundary, micro-vascular tissue internal to the islet, isolated endocrine cells, islet sections with vasculature intact, and finally acinar tissue from around the islet. Unique protein signatures observed in the inner vasculature potentially indicate increased innervation and intra-islet neuron-like crosstalk compared to external vasculature. We also demonstrate the utility of these data for isolating localized structure-specific drug-target interactions using existing protein/drug binding databases.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2019

Interactions between plants and soil shaping the root microbiome under abiotic stress

Plants growing in soil develop close associations with soil microorganisms, which inhabit the areas around, on, and inside their roots. These microbial communities and their associated genes — collectively termed the root microbiome — are diverse and have been shown to play an important role in conferring abiotic stress tolerance to their plant hosts. In light of growing concerns over the threat of water and nutrient stress facing terrestrial ecosystems, especially those used for agricultural production, increased emphasis has been placed on understanding how abiotic stress conditions influence the composition and functioning of the root microbiome and the ultimate consequences for plant health. However, the composition of the root microbiome under abiotic stress conditions will not only reflect shifts in the greater bulk soil microbial community from which plants recruit their root microbiome but also plant responses to abiotic stress, which include changes in root exudate profiles and morphology. Exploring the relative contributions of these direct and plant-mediated effects on the root microbiome has been the focus of many studies in recent years. Here, we review the impacts of abiotic stress affecting terrestrial ecosystems, specifically flooding, drought, and changes in nitrogen and phosphorus availability, on bulk soil microbial communities and plants that interact to ultimately shape the root microbiome. We conclude with a perspective outlining possible directions for future research needed to advance our understanding of the complex molecular and biochemical interactions between soil, plants, and microbes that ultimately determine the composition of the root microbiome under abiotic stress.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2017

Crystal structure of Pistol, a class of self-cleaving ribozyme

Small self-cleaving ribozymes have been discovered in all evolutionary domains of life. They can catalyze site-specific RNA cleavage, and as a result, they have relevance in gene regulation. Comparative genomic analysis has led to the discovery of a new class of small self-cleaving ribozymes named Pistol. We report herein the crystal structure of Pistol at 2.97-Å resolution. Our results suggest that the Pistol ribozyme self-cleavage mechanism likely uses a guanine base in the active site pocket to carry out the phosphoester transfer reaction. The guanine G40 is in close proximity to serve as the general base for activating the nucleophile by deprotonating the 2'-hydroxyl to initiate the reaction (phosphoester transfer). Furthermore, G40 can also establish hydrogen bonding interactions with the nonbridging oxygen of the scissile phosphate. The proximity of G32 to the O5' leaving group suggests that G32 may putatively serve as the general acid. The RNA structure of Pistol also contains A-minor interactions, which seem to be important to maintain its tertiary structure and compact fold. Our findings expand the repertoire of ribozyme structures and highlight the conserved evolutionary mechanism used by ribozymes for catalysis.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1982

Stable polyurethane coatings for electronic circuits. NASA tech briefs, fall 1982, volume 7, no. 1

One of the most severe deficiencies of polyurethanes as engineering materials for electrical applications has been their sensitivity to combined humidity and temperature environments. Gross failure by reversion of urethane connector potting materials has occurred under these conditions. This has resulted in both scrapping of expensive hardware and reduction in reliability in other instances. A basic objective of this study has been to gain a more complete understanding of the mechanisms and interactions of moisture in urethane systems to guide the development of reversion resistant materials for connector potting and conformal coating applications in high humidity environments. Basic polymer studies of molecular weight and distribution, polymer structure, and functionality were carried out to define those areas responsible for hydrolytic instability and to define polymer structural feature conducive to optimum hydrolytic stability.

Source record↗
DOE OSTI2023

Inhibitor-3 inhibits Protein Phosphatase 1 via a metal binding dynamic protein–protein interaction

To achieve substrate specificity, protein phosphate 1 (PP1) forms holoenzymes with hundreds of regulatory and inhibitory proteins. Inhibitor-3 (I3) is an ancient inhibitor of PP1 with putative roles in PP1 maturation and the regulation of PP1 activity. Here, we show that I3 residues 27–68 are necessary and sufficient for PP1 binding and inhibition. In addition to a canonical RVxF motif, which is shared by nearly all PP1 regulators and inhibitors, and a non-canonical SILK motif, I3 also binds PP1 via multiple basic residues that bind directly in the PP1 acidic substrate binding groove, an interaction that provides a blueprint for how substrates bind this groove for dephosphorylation. Unexpectedly, this interaction positions a CCC (cys-cys-cys) motif to bind directly across the PP1 active site. Using biophysical and inhibition assays, we show that the I3 CCC motif binds and inhibits PP1 in an unexpected dynamic, fuzzy manner, via transient engagement of the PP1 active site metals. Together, these data not only provide fundamental insights into the mechanisms by which IDP protein regulators of PP1 achieve inhibition, but also shows that fuzzy interactions between IDPs and their folded binding partners, in addition to enhancing binding affinity, can also directly regulate enzyme activity.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2025

Quantum simulation of boson-related Hamiltonians: techniques, effective Hamiltonian construction, and error analysis

Elementary quantum mechanics proposes that a closed physical system consistently evolves in a reversible manner. However, control and readout necessitate the coupling of the quantum system to the external environment, subjecting it to relaxation and decoherence. Consequently, system-environment interactions are indispensable for simulating physically significant theories. A broad spectrum of physical systems in condensed-matter and high-energy physics, vibrational spectroscopy, and circuit and cavity QED necessitates the incorporation of bosonic degrees of freedom, such as phonons, photons, and gluons, into optimized fermion algorithms for near-future quantum simulations. In particular, when a quantum system is surrounded by an external environment, its basic physics can usually be simplified to a spin or fermionic system interacting with bosonic modes. Nevertheless, troublesome factors such as the magnitude of the bosonic degrees of freedom typically complicate the direct quantum simulation of these interacting models, necessitating the consideration of a comprehensive plan. This strategy should specifically include a suitable fermion/boson-to-qubit mapping scheme to encode sufficiently large yet manageable bosonic modes, and a method for truncating and/or downfolding the Hamiltonian to the defined subspace for performing an approximate but highly accurate simulation, guided by rigorous error analysis. In this pedagogical tutorial review, we aim to provide such an exhaustive strategy, focusing on encoding and simulating certain bosonic-related model Hamiltonians, inclusive of their static properties and time evolutions. Specifically, we emphasize two aspects: (1) the discussion of recently developed quantum algorithms for these interacting models and the construction of effective Hamiltonians, and (2) a detailed analysis regarding a tightened error bound for truncating the bosonic modes for a class of fermion-boson interacting Hamiltonians.

bosonic Hamiltonian↗
DOE OSTI2016

Diverse mechanisms of metaeffector activity in an intracellular bacterial pathogen, Legionella pneumophila

Abstract Pathogens deliver complex arsenals of translocated effector proteins to host cells during infection, but the extent to which these proteins are regulated once inside the eukaryotic cell remains poorly defined. Among all bacterial pathogens, Legionella pneumophila maintains the largest known set of translocated substrates, delivering over 300 proteins to the host cell via its Type IVB , Icm/Dot translocation system. Backed by a few notable examples of effector–effector regulation in L. pneumophila , we sought to define the extent of this phenomenon through a systematic analysis of effector–effector functional interaction. We used Saccharomyces cerevisiae , an established proxy for the eukaryotic host, to query > 108,000 pairwise genetic interactions between two compatible expression libraries of ~330 L. pneumophila‐ translocated substrates. While capturing all known examples of effector–effector suppression, we identify fourteen novel translocated substrates that suppress the activity of other bacterial effectors and one pair with synergistic activities. In at least nine instances, this regulation is direct—a hallmark of an emerging class of proteins called metaeffectors, or “effectors of effectors”. Through detailed structural and functional analysis, we show that metaeffector activity derives from a diverse range of mechanisms, shapes evolution, and can be used to reveal important aspects of each cognate effector's function. Metaeffectors, along with other, indirect, forms of effector–effector modulation, may be a common feature of many intracellular pathogens—with unrealized potential to inform our understanding of how pathogens regulate their interactions with the host cell.

59 BASIC BIOLOGICAL SCIENCES↗