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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS2000

Bioavailability and Pharmacodynamics of Promethazine in Human Subjects

Space Motion Sickness (SMS) is often treated in space with promethazine (PMZ). Anecdotal reports indicate that the common side effects of drowsiness and decrements in cognitive performance that are associated with PMZ administration (50 mg IM on the ground, are absent or less pronounced in space suggesting I that-the bioavailability and/or pharmacodynamic behavior of PMZ may be altered during space flight. There are limited flight opportunities available for clinical research in space, the NRA-99, therefore, solicits research required to improve, or answer specific questions about in-flight diagnosis, therapy, and post-flight rehabilitation. We propose here, to establish a noninvasive method for pharmacodynamic and therapeutic assessment of PMZ. The specific objectives of the proposed research are to, 1. Establish a saliva to plasma ratio of PMZ after administration, 2. Estimate the relative bioavailability of the three flight-specific dosage forms of PMZ, and 3. Establish the dose-response relationship of PMZ. We will estimate the bioavailability of intramuscular injection (IM), oral tablets and rectal suppositories in normal subjects during ambulatory and antiorthostatic; bed rest (ABR) conditions using novel stable isotope techniques. Drowsiness, cognitive performance and salivary flow rate will be measured as a function of circulating drug concentrations after administration of three IM doses of PMZ. We will compare and contrast the bioavailability of PMZ during normal and ABR conditions to examine whether or not ABR can simulate changes in drug, absorption and availability similar to those anticipated in a microgravity environment. Results of this study will validate methods for an approved study with this medication awaiting a flight opportunity for manifestation. These data will also provide the much needed information on the dynamics and therapeutic index. of this medication and their implications on crew fatigue and performance in space. Key words: Promethazine, stable isotopes, bioavailability, pharmacodynamics, cognitive performance, antiorthostatic bed rest.

Putcha, Lakshmi↗
NASA NTRS1996

Method for Producing Non-Neoplastic, Three Dimensional, Mammalian Tissue and Cell Aggregates Under Microgravity Culture Conditions and the Products Produced Therefrom

Normal mammalian tissue and the culturing process has been developed for the three groups of organ, structural, and blood tissue. The cells are grown in vitro under microgravity culture conditions and form three dimensional cells aggregates with normal cell function. The microgravity culture conditions may be microgravity or simulated microgravity created in a horizontal rotating wall culture vessel.

Goodwin, Thomas J.↗
NASA NTRS1925

The application of propeller test data to design and performance calculations

This report is a study of a test data on a family of Durand's propellers (nos. 3, 7, 11, 82, 113, 139), which is fairly representative of conventional design. The test data are so plotted that the proper pitch and diameters for any given set of conditions are readily obtained. The same data are plotted in other forms which may be used for calculating performance when the ratio of pitch to diameter is known. These new plots supply a means for calculating the performance, at any altitude, of airplanes equipped with normal or supercharged engines. The coefficients used and the methods of plotting adopted in this report coordinate the results of a few tests into complete families of curves covering the entire range of p/d ordinarily used. This method of analyzing test data enables an investigator to plan tests systematically and leads to useful application of test data.

Diehl, Walter S↗
NASA NTRS1996

Using Formal Methods to Assist in the Requirements Analysis of the Space Shuttle GPS Change Request

We describe a recent NASA-sponsored pilot project intended to gauge the effectiveness of using formal methods in Space Shuttle software requirements analysis. Several Change Requests (CR's) were selected as promising targets to demonstrate the utility of formal methods in this application domain. A CR to add new navigation capabilities to the Shuttle, based on Global Positioning System (GPS) technology, is the focus of this report. Carried out in parallel with the Shuttle program's conventional requirements analysis process was a limited form of analysis based on formalized requirements. Portions of the GPS CR were modeled using the language of SRI's Prototype Verification System (PVS). During the formal methods-based analysis, numerous requirements issues were discovered and submitted as official issues through the normal requirements inspection process. Shuttle analysts felt that many of these issues were uncovered earlier than would have occurred with conventional methods. We present a summary of these encouraging results and conclusions we have drawn from the pilot project.

DiVito, Ben L.↗
NASA NTRS2010

Evaluation of an ATP Assay to Quantify Bacterial Attachment to Surfaces in Reduced Gravity

Aim: To develop an assay to quantify the biomass of attached cells and biofilm formed on wetted surfaces in variable-gravity environments. Methods and Results: Liquid cultures of Pseudomonas aeruginosa were exposed to 30-35 brief cycles of hypergravity (< 2-g) followed by free fall (i.e., reduced gravity) equivalent to either lunar-g (i.e., 0.17 normal Earth gravity) or micro-g (i.e., < 0.001 normal Earth gravity) in an aircraft flying a series of parabolas. Over the course of two days of parabolic flight testing, 504 polymer or metal coupons were exposed to a stationary-phase population of P. aeruginosa strain ERC1 at a concentration of 1.0 x 10(exp 5) cells per milliliter. After the final parabola on each flight test day, half of the material coupon samples were treated with either 400 micro-g/L ionic silver fluoride (microgravity-exposed cultures) or 1% formalin (lunar-gravity-exposed cultures). The remaining sample coupons from each flight test day were not treated with a fixative. All samples were returned to the laboratory for analysis within 2 hours of landing, and all biochemical assays were completed within 8 hours of exposure to variable gravity. The intracellular ATP luminescent assay accurately reflected cell physiology compared to both cultivation-based and direct-count microscopy analyses. Cells exposed to variable gravity had more than twice as much intracellular ATP as control cells exposed only to normal Earth gravity.

Birmele, Michele N.↗
NASA NTRS1998

Life and death in the microcirculation: a role for angiotensin II

OBJECTIVE: Angiotensin II (ANGII) plays a critical role in the maintenance of the microcirculation and in the anatomical loss of microvessels (rarefaction) that occurs in low renin forms of hypertension and in animals fed a high-salt diet. Elevations in sodium intake can trigger a series of hemodynamic and hormonal responses culminating in a substantial rarefaction of small arterioles and capillaries in both normal and reduced renal mass hypertensive rats. METHODS: Immunohistochemistry, Northern blot, and reverse transcription-polymerase chain reaction (RT-PCR) analysis of microdissected blood vessels were used to localize ANGII receptors in the microcirculation. Chronic infusion of ANGII and other physiologic and pharmacologic manipulations of the reninangiotensin system in rats was combined with morphologic and mathematical analysis of the network architecture. RESULTS: We have shown that rarefaction of the microcirculation can cause an increase in total peripheral resistance, reduced tissue perfusion, decreased oxygen delivery, and impaired organ function. Although the mechanisms by which this occurs are not well understood, a number of key observations point to a role for the renin-angiotensin system in this effect. First, ANGII infused systemically at subpressor levels, or locally into the skeletal muscle interstitium, can induce significant microvessel growth. Second, localization of ANGII receptor proteins by immunohistochemistry and Western blotting and RNA localization by RT-PCR confirm the presence of AT1 receptors, which are growth-stimulatory, and AT2 receptors, which are growth-inhibitory in the microcirculation. Third, maintenance of ANGII at normal levels during periods of hypertension or high-salt diet completely eliminates rarefaction. CONCLUSIONS: Taken together, these results support the hypothesis that ANGII acting through AT1- and AT2-receptor mechanisms modulate vessel density during high-salt diet and hypertension.

Review↗
NASA NTRSDate not supplied

Inverse Text Normalization of Air Traffic Control System Command Center Planning Telecon Transcriptions

We present a hybrid neural network and rule-based Inverse Text Normalization (ITN) method for domains containing unique technical phraseology, specifically ATCSCC planning telecon audio transcriptions. The Air Traffic Control System Command Center (ATCSCC) hosts bihourly planning telephone conferences (or planning telecons) to ensure smooth operations within the National Airspace (NAS). Access to both live and post meeting transcripts of this speech audio would enable quick review of meetings. ITN is the process of converting un-formatted "raw'' speech-to-text transcripts into a human (expert) readable written form. Our hybrid ITN framework utilizes a neural network to format conversational English, and rule-based methods to format domain-specific aviation text. With a preliminary overall Word Error Rate with Punctuation and Capitalization (WER PC) of 8.26, we show that this method has vast potential in being applied to ATCSCC planning telecon audio and other audio/text based data available in ATM.

Air Traffic Management↗
DOE OSTI2021

Dispersion and the speed-limited particle-in-cell algorithm

This paper discusses temporally continuous and discrete forms of the speed-limited particle-in-cell (SLPIC) method first treated by Werner et al. [Phys. Plasmas 25, 123512 (2018)]. The dispersion relation for a 1D1V electrostatic plasma whose fast particles are speed-limited is derived and analyzed. By examining the normal modes of this dispersion relation, we show that the imposed speed-limiting substantially reduces the frequency of fast electron plasma oscillations while preserving the correct physics of lower-frequency plasma dynamics (e.g. ion acoustic wave dispersion and damping). We then demonstrate how the timestep constraints of conventional electrostatic particle-in-cell methods are relaxed by the speed-limiting approach, thus enabling larger timesteps and faster simulations. Here, these results indicate that the SLPIC method is a fast, accurate, and powerful technique for modeling plasmas wherein electron kinetic behavior is nontrivial (such that a fluid/Boltzmann representation for electrons is inadequate) but evolution is on ion timescales.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS1980

Evaluation of approximate methods for the prediction of noise shielding by airframe components

An evaluation of some approximate methods for the prediction of shielding of monochromatic sound and broadband noise by aircraft components is reported. Anechoic-chamber measurements of the shielding of a point source by various simple geometric shapes were made and the measured values compared with those calculated by the superposition of asymptotic closed-form solutions for the shielding by a semi-infinite plane barrier. The shields used in the measurements consisted of rectangular plates, a circular cylinder, and a rectangular plate attached to the cylinder to simulate a wing-body combination. The normalized frequency, defined as a product of the acoustic wave number and either the plate width or cylinder diameter, ranged from 4.6 to 114. Microphone traverses in front of the rectangular plates and cylinders generally showed a series of diffraction bands that matched those predicted by the approximate methods, except for differences in the magnitudes of the attenuation minima which can be attributed to experimental inaccuracies. The shielding of wing-body combinations was predicted by modifications of the approximations used for rectangular and cylindrical shielding. Although the approximations failed to predict diffraction patterns in certain regions, they did predict the average level of wing-body shielding with an average deviation of less than 3 dB.

Ahtye, W. F.↗
NASA NTRS1992

Dynamics of interacting galaxies

The dynamics of interacting galaxies as observed in the present epoch is reviewed. Topics discussed include numerical methods for modeling galactic interactions, the signatures of interacting galaxies due to tidal forces, and events that add mass to a galaxy. The review also covers major mergers between systems of comparable mass, forms of activity triggered or induced by galactic interactions, and galaxies' return to normality and related cosmological issues. Finally, some questions that yet have to be answered are examined.

Barnes, Joshua E.↗
DOE OSTI2023

Simulation of a TRISO MiniFuel irradiation experiment with data-informed uncertainty quantification

An irradiation experiment using tristructural isotropic (TRISO) fuel particles and the miniature fuel (MiniFuel) irradiation vehicle was performed in Oak Ridge National Laboratory’s High Flux Isotope Reactor (HFIR) to support development of the Kairos Power fluoride salt–cooled, high-temperature reactor (KP-FHR). Here, this paper describes modeling predictions of temperatures and fuel burnup for the as-built experiment. An uncertainty quantification (UQ) analysis was performed to determine the effect of TRISO particle volume and position on the temperature predictions at various fuel heat generation rates (HGRs). This UQ study utilized fuel kernel position and volume measurements previously collected using X-ray computed tomography (XCT) techniques and Monte Carlo sampling methods to generate fuel compact cases that were then analyzed using a finite element thermal model. The UQ analysis indicated that uncertainty in calculated temperatures caused by varying TRISO particle arrangement is relatively small, even at high fuel HGR. Final predictions of particle temperatures throughout the irradiation are shown to be relevant to KP-FHR normal and off-normal operating conditions and to previous TRISO irradiation experiments. The combination of XCT with UQ analyses will inform post-irradiation examination (PIE) of the irradiated fuel compacts, and these analyses can be used to develop fuel performance models for coated particle fuel forms. Both PIE of separate-effects irradiation data and enhanced fuel performance modeling support accelerated qualification of TRISO fuels for a broad range of advanced reactor applications. The novel approach demonstrated here of measuring TRISO particle configurations with XCT methods and generating representative fuel compacts for finite element modeling and UQ analysis could be leveraged by the broader particle fuel community in the development of other TRISO fuel experiments in which these variables may have a significant impact on key outcomes.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
NASA NTRS1977

Analysis of shear test method for composite laminates

An elastic plane stress finite element analysis of the stress distributions in four flat test specimens for in-plane shear response of composite materials subjected to mechanical or thermal loads is presented. The shear test specimens investigated include: slotted coupon, cross beam, losipescu, and rail shear. Results are presented in the form of normalized shear contour plots for all three in-plane stess components. It is shown that the cross beam, losipescu, and rail shear specimens have stress distributions which are more than adequate for determining linear shear behavior of composite materials. Laminate properties, core effects, and fixture configurations are among the factors which were found to influence the stress distributions.

Bergner, H. W., Jr.↗
NASA NTRS1985

Adaptive Inverse Control for Rotorcraft Vibration Reduction

This thesis extends the Least Mean Square (LMS) algorithm to solve the mult!ple-input, multiple-output problem of alleviating N/Rev (revolutions per minute by number of blades) helicopter fuselage vibration by means of adaptive inverse control. A frequency domain locally linear model is used to represent the transfer matrix relating the higher harmonic pitch control inputs to the harmonic vibration outputs to be controlled. By using the inverse matrix as the controller gain matrix, an adaptive inverse regulator is formed to alleviate the N/Rev vibration. The stability and rate of convergence properties of the extended LMS algorithm are discussed. It is shown that the stability ranges for the elements of the stability gain matrix are directly related to the eigenvalues of the vibration signal information matrix for the learning phase, but not for the control phase. The overall conclusion is that the LMS adaptive inverse control method can form a robust vibration control system, but will require some tuning of the input sensor gains, the stability gain matrix, and the amount of control relaxation to be used. The learning curve of the controller during the learning phase is shown to be quantitatively close to that predicted by averaging the learning curves of the normal modes. For higher order transfer matrices, a rough estimate of the inverse is needed to start the algorithm efficiently. The simulation results indicate that the factor which most influences LMS adaptive inverse control is the product of the control relaxation and the the stability gain matrix. A small stability gain matrix makes the controller less sensitive to relaxation selection, and permits faster and more stable vibration reduction, than by choosing the stability gain matrix large and the control relaxation term small. It is shown that the best selections of the stability gain matrix elements and the amount of control relaxation is basically a compromise between slow, stable convergence and fast convergence with increased possibility of unstable identification. In the simulation studies, the LMS adaptive inverse control algorithm is shown to be capable of adapting the inverse (controller) matrix to track changes in the flight conditions. The algorithm converges quickly for moderate disturbances, while taking longer for larger disturbances. Perfect knowledge of the inverse matrix is not required for good control of the N/Rev vibration. However it is shown that measurement noise will prevent the LMS adaptive inverse control technique from controlling the vibration, unless the signal averaging method presented is incorporated into the algorithm.

Jacklin, Stephen A.↗
DOE OSTI2023

Finite-temperature many-body perturbation theory for anharmonic vibrations: Recursions, algebraic reduction, second-quantized reduction, diagrammatic rules, linked-diagram theorem, finite-temperature self-consistent field, and general-order algorithm

A unified theory is presented for finite-temperature many-body perturbation expansions of the anharmonic vibrational contributions to thermodynamic functions, i.e., the free energy, internal energy, and entropy. The theory is diagrammatically size-consistent at any order, as ensured by the linked-diagram theorem proved in this study, and, thus, applicable to molecular gases and solids on an equal footing. It is also a basis-set-free formalism, just like its underlying Bose–Einstein theory, capable of summing anharmonic effects over an infinite number of states analytically. It is formulated by the Rayleigh–Schrödinger-style recursions, generating sum-over-states formulas for the perturbation series, which unambiguously converges at the finite-temperature vibrational full-configuration-interaction limits. Two strategies are introduced to reduce these sum-over-states formulas into compact sum-over-modes analytical formulas. One is a purely algebraic method that factorizes each many-mode thermal average into a product of one-mode thermal averages, which are then evaluated by the thermal Born–Huang rules. Canonical forms of these rules are proposed, dramatically expediting the reduction process. The other is finite-temperature normal-ordered second quantization, which is fully developed in this study, including a proof of thermal Wick’s theorem and the derivation of a normal-ordered vibrational Hamiltonian at finite temperature. The latter naturally defines a finite-temperature extension of size-extensive vibrational self-consistent field theory. These reduced formulas can be represented graphically as Feynman diagrams with resolvent lines, which include anomalous and renormalization diagrams. Two order-by-order and one general-order algorithms of computing these perturbation corrections are implemented and applied up to the eighth order. The results show no signs of Kohn–Luttinger-type nonconvergence.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2020

Quasiparticle conductance in spin valve Josephson structures

We study the quasiparticle current in clean ferromagnetic Josephson structures of the form $S_1/F_1/N/F_2/S_2$, where $\textit{S, F,}$ and $\textit{N}$ denote superconducting, ferromagnetic, or normal layers, respectively. Our focus is on the structure of the conductance $\textit{G}$ as a function of bias $\textit{V$, emphasizing the subgap region. We use a fully self-consistent numerical method, coupled to a transfer matrix procedure to extract $\textit{G(V)}$. We choose material parameters appropriate to experimentally realized Co Cu Nb structures. In this work, we find a resonance peak structure as a function of the intermediate layer thickness and of the misalignment angle $\phi$ between $\textit{F}$ layers. To understand this resonance structure, we develop an approximate analytic method. For experimentally relevant thicknesses, the conductance has multiple subgap peaks, which oscillate in position between low and critical bias positions. These oscillations occur in both $\phi$ and the layer thicknesses. We compare our results with those obtained for the spin valve structures ($F_1/N/F_2/S_2$) and discuss the implications of our results for the fabrication of spin Josephson devices.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
NASA NTRS1982

Static calibration for measurement of loads in wind tunnel tests on Shuttle surface tiles

A description is given of the procedures used for the static calibrations of the Coe (1981) sensor array to determine normal force, pitching moment, and rolling moment from the ensemble of sensor outputs. The use of independent data to confirm the validity of the calibration is also described. Two methods are used in calibrating the Coe sensors. In the first, calibration loads and readings are arranged in matrix form and are assumed to be related in a linear fashion. In the second, each Coe sensor reading is regarded as a sum of contributions from each of the calibration loads. It is shown that the Coe load sensors, in conjunction with either of two data analysis methods, can be used to determine the forces and moments experienced by a Shuttle TPS tile.

Rummler, D. R.↗
NASA NTRS1975

Analysis of the dynamic response of a supersonic inlet to flow-field perturbations upstream of the normal shock

A linearized mathematical analysis is presented for determining the response of normal shock position and subsonic duct pressures to flow-field perturbations upstream of the normal shock in mixed-compression supersonic inlets. The inlet duct cross-sectional area variation is approximated by constant-area sections; this approximation results in one-dimensional wave equations. A movable normal shock separates the supersonic and subsonic flow regions, and a choked exit is assumed for the inlet exit condition. The analysis leads to a closed-form matrix solution for the shock position and pressure transfer functions. Analytical frequency response results are compared with experimental data and a method of characteristics solution.

Cole, G. L.↗
NASA NTRS2004

Bioavailability and Pharmacodynamics of Promethazine on Long Duration Missions to the International Space Station

Space motion sickness (SMS) is often treated in space with promethazine (PMZ). Common side effects of PMZ administration (50 mg intramuscular) on the ground are drowsiness and impaired cognitive performance. Anecdotal reports indicate that these effects are absent or less pronounced in space. This suggests that the availability of PMZ to the body (bioavailability) and/or the response of the body to PMZ (pharmacodynamics) may change during space flight. Opportunities for clinical research in space are limited. The study described here is our response to a NASA Research Announcement for proposals for flight-based research needed to improve, or answer specific questions about, diagnosis and therapy during space flight, and post-flight rehabilitation. We propose here to evaluate noninvasive methods for determining the bioavailability and pharmacodynamics of PMZ. The specific objectives of the proposed research are to 1) compare pharmacokinetic and pharmacodynamic parameters of PMZ, estimated from saliva and plasma levels after administration of PMZ, 2) estimate the relative bioavailability of the three dosage forms of PMZ that are often administered to control motion sickness symptoms in space, and 3) establish the dose-response relationship of PMZ. We will estimate the bioavailability of an intramuscular injection (IM), oral tablet, and rectal suppository of PMZ in noma1 subjects during ambulatory and antiorthostatic bed rest (ABR) conditions using novel stable isotope techniques. We will compare and contrast the bioavailability of PMZ during normal and microgravity conditions to examine changes in drug absorption and bioavailability during microgravit. Results of this study will validate methods for an approved in-flight investigation with this medication awaiting an opportunity for manifestation..

Putcha, Lakshmi↗