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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Special processing of Apollo 16 Pan Camera film

Due to the exposure conditions of the Apollo 16 Pan Camera imagery, a series of tests were run to determine if it was possible to: (1) maintain toe speed to preserve the normally exposed near-terminator imagery, and (2) retain an acceptable density range for the two stop overexposed portion of the imagery. A set of processing conditions (80 F, 15 fpm) was found which provide a significant improvement over the Standard Apollo 16 Control for Film Type 3414 in meeting the requirements.

Weinstein, M. S.↗
NASA NTRS1980

Rotatable prism for pan and tilt

Compact, inexpensive, motor-driven prisms change field of view of TV camera. Camera and prism rotate about lens axis to produce pan effect. Rotating prism around axis parallel to lens produces tilt. Size of drive unit and required clearance are little more than size of camera.

Ball, W. B.↗
NASA NTRS1982

PAN AIR summary document (version 1.0)

The capabilities and limitations of the panel aerodynamics (PAN AIR) computer program system are summarized. This program uses a higher order panel method to solve boundary value problems involving the Prandtl-Glauert equation for subsonic and supersonic potential flows. Both aerodynamic and hydrodynamic problems can be solved using this modular software which is written for the CDC 6600 and 7600, and the CYBER 170 series computers.

Derbyshire, T.↗
NASA NTRS1986

PAN AIR application to the F-106B

The PAN AIR computer code was employed in the present study to investigate the aerodynamic effects of the various geometrical changes and flow conditions on a configuration similar to the F-106B half-airplane tested in the Langley 30x60-foot wind tunnel. The various geometries studied included two forebodies (original and shortened), two inlet flow conditions (open and closed) two vortex flap situations (off and on). The attached flow theoretical solutions were obtained for Mach number of 0.08 and angle of attack of 8 deg., 10 deg., 12 deg., and 14 deg. In general this investigation revealed that the shortening of the forebody or closing of the inlet produced only a small change in the overall aerodynamic coefficients of the basic F-106B configuration throughout the examined angles of attack. However, closing the inlet of the configuration resulted in a slightly higher drag level at low angles of attack. Furthermore, at and above 10 deg. angle of attack, it was shown that the presence of the vortex flap causes an increase in the total lift and drag. Also, these theoretical results showed the expected reduction in longitudinal stability level with addition of the vortex flap to the basic F-106B configuration.

Farhad Ghaffari↗
NASA NTRS1990

PAN AIR: A computer program for predicting subsonic or supersonic linear potential flows about arbitrary configurations using a higher order panel method. Volume 1: Theory document (version 3.0)

An outline of the derivation of the differential equation governing linear subsonic and supersonic potential flow is given. The use of Green's Theorem to obtain an integral equation over the boundary surface is discussed. The engineering techniques incorporated in the Panel Aerodynamics (PAN AIR) program (a discretization method which solves the integral equation for arbitrary first order boundary conditions) are then discussed in detail. Items discussed include the construction of the compressibility transformation, splining techniques, imposition of the boundary conditions, influence coefficient computation (including the concept of the finite part of an integral), computation of pressure coefficients, and computation of forces and moments. Principal revisions to version 3.0 are the following: (1) appendices H and K more fully describe the Aerodynamic Influence Coefficient (AIC) construction; (2) appendix L now provides a complete description of the AIC solution process; (3) appendix P is new and discusses the theory for the new FDP module (which calculates streamlines and offbody points); and (4) numerous small corrections and revisions reflecting the MAG module rewrite.

Epton, Michael A.↗
NASA NTRS1991

The Pan-European Digital Cellular (GSM) System

This paper presents an overview of the Pan-American Cellular System (GSM). Much of the information is generic to the GSM architecture and operation, as defined in ETSI Recommendations 1 to 12.

Lev, Valy↗
NASA NTRS1992

Late Proterozoic evolution of the northern part of the Hamisana zone, northeast Sudan - Constraints on Pan-African accretionary tectonics

This paper describes deformation fabrics developed in the northern part of the Hamisana zone in northeast Sudan. New structural data are presented which establish a structural chronology that characterizes distinct events of accretion, folding, and thrust faulting and reactivation of accretion-related faults. The structural data point to an intraplate compressional origin for the Hamisana zone. A review of available isotopic age data is carried out, and it is concluded that Pan-African accretionary processes may have been analogous to Phanerozoic ophiolite and island arc accretion in the western North American Cordillera, where penetrative deformation occurred in response to periodic intraplate shortening events, rather than an ultimate collision of unrelated crustal fragments.

Miller, M. M.↗
NASA NTRS2003

Measurement of Peroxyacetyl Nitrate (PAN), Peroxypropionyl Nitrate (PPN) and Peroxymethacryloyl Nitrate (MPAN) during TRACE-P

In Fall 2000, the PANs gas chromatograph (GC) was improved and prepared for installation on the NASA P-3. A number of experiments were conducted in conjunction with the NCAR NO,, instrument (B. Ridley) to settle some of the fine details of the output of the calibration system for each instrument. In addition, the sampling frequency was improved.

Flocke, Frank↗
NASA NTRS2004

A Two-Stage Procedure Toward the Efficient Implementation of PANS and Other Hybrid Turbulence Models

The main objective of this article is to introduce and to show the implementation of a novel two-stage procedure to efficiently estimate the level of scale resolution possible for a given flow on a given grid for Partial Averaged Navier-Stokes (PANS) and other hybrid models. It has been found that the prescribed scale resolution can play a major role in obtaining accurate flow solutions. The first step is to solve the unsteady or steady Reynolds Averaged Navier-Stokes (URANS/RANS) equations. From this preprocessing step, the turbulence length-scale field is obtained. This is then used to compute the characteristic length-scale ratio between the turbulence scale and the grid spacing. Based on this ratio, we can assess the finest scale resolution that a given grid for a given flow can support. Along with other additional criteria, we are able to analytically identify the appropriate hybrid solver resolution for different regions of the flow. This procedure removes the grid dependency issue that affects the results produced by different hybrid procedures in solving unsteady flows. The formulation, implementation methodology, and validation example are presented. We implemented this capability in a production Computational Fluid Dynamics (CFD) code, PAB3D, for the simulation of unsteady flows.

Abdol-Hamid, Khaled S.↗
NASA NTRS2007

ACE-FTS Observation of a Young Biomass Burning Plume: First Reported Measurements of C2H4, C3H6O, H2CO and PAN by Infrared Occultation from Space

In the course of our study of the upper tropospheric composition with the infrared 35 Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE FTS), we 36 found an occultation sequence that on 8 October 2005, sampled a remarkable plume near the 37 east coast of Tanzania. Model simulations of the CO distribution in the Southern hemisphere 38 are performed for this period and they demonstrate that the emissions for this event originated 39 from a nearby forest fire, after which the plume was transported from the source region to the 40 upper troposphere. Taking advantage of the very high signal-to-noise ratio of the ACE FTS 41 spectra over a wide wavenumber range (750-4400 cm(exp -1), we present in-depth analyses of the 42 chemical composition of this plume in the middle and upper troposphere, focusing on the 43 measurements of weakly absorbing pollutants. For this specific biomass burning event, we 44 report simultaneous observations of an unprecedented number of organic species. 45 Measurements of C2H4 (ethene), C3H4 (propyne), H2CO (formaldehyde), C3H6O (acetone) 46 and CH3COO2NO2 (perxoxyacetylnitrate, abbreviated as PAN) are the first reported 47 detections using infrared occultation spectroscopy from satellites. Based on the lifetime of the 48 emitted species, we discuss the photochemical age of the plume and also report, whenever 49 possible, the enhancement ratios relative to CO.

Coheur, Pierre-Francois↗
NASA NTRS2007

The Spatiotemporal Structure of 20th Century Climate Variations in Observations and Reanalyses: Pacific Pan-Decadal Variability - Part 2

The dominant interannual El Nino-Southern Oscillation phenomenon (ENSO) and the short length of climate observation records make it difficult to study long-term climate variations in the spatiotemporal domain. Based on the fact that the ENS0 signal spreads to remote regions and induces delayed climate variation through atmospheric teleconnections, we develop an ENSO-removal method through which the ENS0 signal can be approximately removed at the grid box level from the spatiotemporal field of a climate parameter. After this signal is removed, long-term climate variations, namely, the global warming trend (GW) and the Pacific pan-decadal variability (PDV), are isolated at middle and low latitudes in the climate parameter fields from observed and reanalyses datasets. In this study, we show that one of several PDV interdecadal regime shifts occurred during the 1990s. This significant change in the Pacific basin is comparable but opposite in phase to the 1976 climate regime shift, which results persisting warming in the central-eastern Pacific, and cooling in the North and South Pacific. The 1990s PDV regime shift is consistent with observed changes in ocean biosphere and ocean circulation. A comprehensive picture of PDV as manifested in the troposphere and at the surface is described. In general, the PDV spatial patterns in different parameter fields share some similarities with the patterns associated with ENSO, but important differences exist. First, the PDV atmospheric circulation pattern is shifted westward by about 20deg and its zonal extent is limited to approx.60deg compared to approx.110deg for ENS0 pattern. The westward shift of the PDV wave train produces a different, more west-east oriented, North American teleconnection pattern. The lack of a strong PDV surface temperature (ST) signal in the western equatorial Pacific and the relatively strong ST signal in the subtropical regions are consistent with an atmospheric overturning circulation response that differs from the one associated with ENSO.

Chen, Junye↗
NASA NTRS1981

PAN AIR: A Computer Program for Predicting Subsonic or Supersonic Linear Potential Flows About Arbitrary Configurations Using a Higher Order Panel Method: Theory Document (Version 1.1) - Volume 1

An outline of the derivation of the differential equation governing linear subsonic and supersonic potential flow is given. The use of Green's Theorem to obtain an integral equation over the boundary surface is discussed. The engineering techniques incorporated in the PAN AIR (Panel Aerodynamics) program (a discretization method which solves the integral equation for arbitrary first order boundary conditions) are then discussed in detail. Items discussed include the construction of the compressibility transformations, splining techniques, imposition of the boundary conditions, influence coefficient computation (including the concept of the finite part of an integral), computation of pressure coefficients, and computation of forces and moments.

Magnus, Alfred E.↗
NASA NTRS2016

Development of Advanced Conformal Ablative TPS Fabricated from Rayon- and PAN-Based Carbon Felts

The conformal ablative TPS first developed under NASA's Hypersonics Project in the early 2000's demonstrated very low through the thickness conductivity compared to state-ofthe- art PICA. However, in initial arcjet testing of Conformal-1, surface recession rates were 2x higher than PICA. Because commercial carbon felts are currently available as very thin substrates, this was a concern if conformal TPS were to be considered for a mission that required thicker material. Discussed in this paper are the results of the development of an Advanced Conformal TPS derived from thicker, higher density carbon felt. Two substrate systems were evaluated, the first material was a needled rayon-based carbon felt and the other a needled PAN-based carbon felt. Both substrates were impregnated with phenolic resin following the PICA/CPICA process to add a low density phenolic matrix to the system prior to aerothermal screening at the LaRC HyMETS facility and larger scale testing in the NASA ARC Interaction Heating Facility (IHF) at heating fluxes ranging from 250-1700 W/cm2.

Arcjet Testing↗
NASA NTRS2017

A Pan-Tropical Cascade of Fire Driven by El Nino/Southern Oscillation

The El Nino/Southern Oscillation (ENSO) has a pronounced influence on year-to-year variations in climate. The response of fires to this forcing is complex and has not been evaluated systematically across different continents. Here we use satellite data to create a climatology of burned-area and fire emissions responses, drawing on six El Nino and six La Nina events during 1997-2016. On average, reductions in precipitation and terrestrial water storage increased fire emissions in pan-tropical forests by 133% during and following El Nino as compared with La Nina. Fires peaked in equatorial Asia early in the ENSO cycle when El Nino was strengthening (Aug-Oct), before moving to southeast Asia and northern South America (Jan-Apr), Central America (Mar-May) and the southern Amazon (Jul-Oct) during the following year. Large decreases in fire occurred across northern Australia during Sep-Oct of the second year from a reduced fuel availability. Satellite observations of aerosols and carbon monoxide provided independent confirmation of the spatiotemporal evolution of fire anomalies. The predictable cascade of fire across different tropical continents described here highlights an important time delay in the Earth system's response to precipitation redistribution. These observations help to explain why the growth rate of atmospheric CO2 increases during El Nino and may contribute to improved seasonal fire forecasts.

Chen, Yang↗
NASA NTRSDate not supplied

Joint Assimilation of CO, O3, NO2, SO2, PM, AOD, NH4, PAN, and HNO3 in Support of the Tropospheric Regional Atmospheric Composition and Emissions Reanalysis (2005 - 2024) (TRACER-I)

NASA Ames Research Center is collaborating with the NOAA Chemical Systems Laboratory (NOAA/CSL), the NASA Jet Propulsion Laboratory (JPL), the NASA Goddard Modeling and Assimilation Office, and the National Center for Atmospheric Research to prepare a 20-year Tropospheric Regional Atmospheric Composition and Emissions Reanalysis (2005 – 2024) (TRACER-I) for the continental United States during the summer ozone (O3) and wildfire seasons (April to October). TRACER-I will be a regional complement to JPL’s global Tropospheric Chemistry Reanalyses II and III. We will use WRF-Chem/DART with NOAA/CSL’s WRF-Chem setup at 12 km x 12 km horizontal resolution, 51 vertical levels, and 30 ensemble members. We will assimilate: (i) conventional meteorological observations; (ii) EPA’s Air Quality System in situ measurements of carbon monoxide (CO), O3, nitrogen dioxide (NO2), sulfur dioxide (SO2), particulate matter (PM) with diameters less than 10 µm (PM10), and PM with diameters less than 2.5 µm (PM2.5); and (iii) MOPITT, MODIS, OMI, TROPOMI, GOME-2a, MLS, TES, SCIAMACHY, CrIS, and TEMPO total/partial column and/or profile retrievals of CO, O3, NO2, SO2, aerosol optical depth (AOD), formaldehyde (HCHO), ammonia (NH4), peroxyacetyl nitrate (PAN), and/or nitric acid (HNO3) with 3-hr cycling. We will present an overview of this project, its status, and available results (likely the analysis of sensitivity experiment results from the assimilation/emissions estimation system).

data assimilation↗
NASA NTRS2024

Thermal Conductivity and Mechanical Properties of Epoxy Composites With Hybridized PAN- and Pitch-Based Fiber Architecture

A series of hybrid polyacrylonitrile- (PAN-) and pitch-based carbon fiber/epoxy composites were fabricated and tested to evaluate the influence of hybrid fiber configurations on composite strength, modulus, and through-thickness thermal conductivity. Two grades of pitch-based fiber were selected based on their thermal conductivity: YSH-60A and YSH-80A from Nippon Graphite. These pitch-based fibers were received in tow form and as plain weave to allow flexibility in the architecture of the multifiber laminate. Two hybridization approaches were followed: (1) interleave of pitch-based fiber weave within braided PAN/epoxy prepreg and (2) incorporation of pitch-based fiber tows within a three-dimensional braided preform. These showed considerable impact on overall composite mechanical properties and through-thickness thermal conductivity.

Polymer Composite↗