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Results for “Radiation testing”

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 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

Radiation from advanced solid rocket motor plumes

The overall objective of this study was to develop an understanding of solid rocket motor (SRM) plumes in sufficient detail to accurately explain the majority of plume radiation test data. Improved flowfield and radiation analysis codes were developed to accurately and efficiently account for all the factors which effect radiation heating from rocket plumes. These codes were verified by comparing predicted plume behavior with measured NASA/MSFC ASRM test data. Upon conducting a thorough review of the current state-of-the-art of SRM plume flowfield and radiation prediction methodology and the pertinent data base, the following analyses were developed for future design use. The NOZZRAD code was developed for preliminary base heating design and Al2O3 particle optical property data evaluation using a generalized two-flux solution to the radiative transfer equation. The IDARAD code was developed for rapid evaluation of plume radiation effects using the spherical harmonics method of differential approximation to the radiative transfer equation. The FDNS CFD code with fully coupled Euler-Lagrange particle tracking was validated by comparison to predictions made with the industry standard RAMP code for SRM nozzle flowfield analysis. The FDNS code provides the ability to analyze not only rocket nozzle flow, but also axisymmetric and three-dimensional plume flowfields with state-of-the-art CFD methodology. Procedures for conducting meaningful thermo-vision camera studies were developed.

Farmer, Richard C.↗
NASA NTRS1989

Gravitational radiation as a test of relativistic gravity

Gravitational radiation can be used to test theories of gravitation. When the waves are ultimately detected directly, their speed and polarization properties can be measured and compared with predictions of alternative theories. The multipole nature of gravitational radiation was already tested in the binary pulsar, where observations of the decay of the orbit verify the quadrupole formula for gravitational radiation damping of general relativity and put strong constraints on dipole gravitational radiation predicted by many alternative theories.

Will, Clifford M.↗
NASA NTRS1982

Reflective-Shield Radiative Cooler

Tests show radiative cooler consisting of several thin reflective shields with a slight angle between them redirects flow of heat very effectively. Shield can be used for deflecting virtually any level of thermal radiation can be deflected by technique; but it may be useful in construction reflecting baffles in front of ovens or furnaces.

Petrick, W.↗
NASA NTRS2010

IR Thermography of International Space Station Radiator Panels

Several non-flight qualification test radiators were inspected using flash thermography. Flash thermography data analysis used raw and second derivative images to detect anomalies (Echotherm and Mosaic). Simple contrast evolutions were plotted for the detected anomalies to help in anomaly characterization. Many out-of-family indications were noted. Some out-of-family indications were classified as cold spot indications and are due to additional adhesive or adhesive layer behind the facesheet. Some out-of-family indications were classified as hot spot indications and are due to void, unbond or lack of adhesive behind the facesheet. The IR inspection helped in assessing expected manufacturing quality of the radiators.

Koshti, Ajay↗
NASA NTRS2017

It's All Relative: A Validation of Radiation Quality Comparison Metrics

The difference between high-LET and low-LET radiation is quantified by a measure called relative biological effectiveness (RBE). RBE is defined as the ratio of the dose of a reference radiation to that of a test radiation to achieve the same effect level, and thus, is described either as an iso-effector dose-to-dose ratio. A single dose point is not sufficient to calculate an RBE value; therefore, studies with only one dose point usually calculate an effect-to-effect ratio. While not formally used in radiation protection, these iso-dose values may still be informative. Shuryak, et al 2017 investigated the use of an iso-dose metric termed "radiation effects ratio" (RER) and used both RBE and RER to estimate high-LET risks. To apply RBE or RER to risk prediction, the selected metric must be uniquely defined. That is, the calculated value must be consistent within a model given a constant set of constraints and assumptions, regardless of how effects are defined using statistical transformations from raw endpoint data. We first test the RBE and the RER to determine whether they are uniquely defined using transformations applied to raw data. Then, we test whether both metrics can predict heavy ion response data after simulated effect size scaling between human populations or when converting animal to human endpoints.

Chappell, Lori J.↗
NASA NTRS1994

Test problems for radiation and radiation-hydrodynamics codes

A number of test problems for radiation and radiation-hydrodynamics computer codes are described. These include evolution to radiative equilibrium, cooling from radiative equilibrium, subcritical and supercritical radiating shocks, and a radiating blast wave in a power-law density distribution. For each test problem, example input parameters and plots of the results are presented. Some test problems for pure hydrodynamics are also suggested. The radiation-hydrodynamics code used to perform the example test problems and the equations it solves are described in some detail.

Ensman, Lisa↗
NASA NTRS2015

Radiation Engineering for Designers

This tutorial provides an overview of the natural space radiation environment, an introduction to radiation effect types, an overview of EEE parts selection, scrubbing, and radiation mitigation, and an introduction to radiation testing.

radiation effects↗
NASA NTRS2015

Radiation Engineering for Designers

This tutorial provides an overview of the natural space radiation environment, an introduction to radiation effect types, an overview of EEE parts selection, scrubbing, and radiation mitigation, and an introduction to radiation testing.

radiation effects↗
NASA NTRS1928

Resistance and Cooling Power of Various Radiators

This reports combines the wind tunnel results of radiator tests made at the Navy Aerodynamical Laboratory in Washington during the summers of 1921, 1925, and 1926. In all, 13 radiators of various types and capacities were given complete tests for figure of merit. Twelve of these were tested for resistance to water flow and a fourteenth radiator was tested for air resistance alone, its heat dissipating capacity being known. All the tests were conducted in the 8 by 8 foot tunnel, or in its 4 by 8 foot restriction, by the writer and under conditions as nearly the same as possible. That is to say, as far as possible, the general arrangement and condition of the apparatus, the observation intervals, the ratio of water flow per unit of cooling surface, the differential temperatures, and the air speeds were the same for all.

Smith, R H↗
NASA NTRS2020

In-Situ Testing Methods for Mixed-Mode Harsh Environments

Future NASA missions are driving a need for instrumentation and space electronics that will operate at extreme temperatures, with low mass and extended deployments. This need results in devices that will experience dose damage at both low and high temperatures that will suppress annealing and induce accelerated wear out issues. Therefore, the ability to perform radiation tests on devices at temperature is critical. This paper analyses the methods and process to enable these test as developed at the JPL Dynamitron Facility. Since electronics are the radiation source for this facility, the steps to ensure parity with cobalt-60 testing are discussed. Also discussed are the implications for system level testing and mixed radiation mode testing for highly integrated and scaled devices.

Scheick, Leif Z↗
NASA NTRS2006

Deep Space Test Bed for Radiation Studies

The Deep Space Test-Bed (DSTB) Facility is designed to investigate the effects of galactic cosmic rays on crews and systems during missions to the Moon or Mars. To gain access to the interplanetary ionizing radiation environment the DSTB uses high-altitude polar balloon flights. The DSTB provides a platform for measurements to validate the radiation transport codes that are used by NASA to calculate the radiation environment within crewed space systems. It is also designed to support other Exploration related investigations such as measuring the shielding effectiveness of candidate spacecraft and habitat materials, testing new radiation monitoring instrumentation and flight avionics and investigating the biological effects of deep space radiation. We describe the work completed thus far in the development of the DSTB and its current status.

Adams, James H.↗
NASA NTRS1997

Antifuse FPGA for Space Applications

This paper presents viewgraphs of Antifuse FPGA (Field Programmable Gate Array) for Space Applications. The topics include: 1) A32140DX TID Test; 2) A1280XL Proton Test; 3) SEU (Single Event Upsets) Rate Calculation; 4) Recent Products Test; 5) A1460A TID (Traveling Ionospheric Disturbances) Test; 6) I100 Proton Test; 7) 100/RHI100 SEU Test; 8) I100/RH100 TID Test; 9) A1020S TID Test; 10) TID Charge Pump Failure; 11) Radiation Testing; and SEE (Single Event Effects) Test Setup.

Wang, Jih-Jong↗
NASA NTRS2016

Field Programmable Gate Aray (FPGA) Radiation Data: All Data is Not Equal

Electronic parts (integrated circuits) have grown in complexity such that determining all failure modes and risks based on single particle event radiation testing is impossible. In this presentation, the authors will present why this is so and provide some realism on what this means to FPGAs. Its all about understanding actual risks and not making assumptions.

radiation testing↗
NASA NTRS1997

Degradation of Precision Reference Devices in Space Environments

This paper presents radiation test results for several different precision voltage devices. Their degradation is compared to that expected for the basic bandgap reference circuit, which is used as a theoretical benchmark, and uses only npn transistorss.

Precision↗