Evaluation of refractory fabrics for flexible heat shields.
Testing machine for evaluating high temperature fabrics under dynamic loading and heating conditions
LOAD TESTING MACHINE↗
SEARCH · Engineering Papers
Results for “dynamic temperature”
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.
A study of the general dynamics of the physical-chemical systems in mammals Final report
Dynamic aspects of temperature regulating system, cardiovascular system, hormonal system, central nervous system, and behavior in mammals
Iberall, A. S.↗
A study of the general dynamics of the physical-chemical systems in mammals Final report
General dynamics of mammalian temperature regulating system, cardiovascular system, hormonal system, central nervous system, and behavior
Iberall, A. S.↗
OSO-7 Orbiting Solar Observatory program
The seventh Orbiting Solar Observatory (OSO-7) in the continuing series designed to gather solar and celestial data that cannot be obtained from the earth's surface is described. OSO-7 was launched September 29, 1971. It has been highly successful in returning scientific data giving new and important information about solar flare development, coronal temperature variations, streamer dynamics of plasma flow, and solar nuclear processes. OSO-7 is expected to have sufficient lifetime to permit data comparisons with the Skylab A mission during 1973. The OSO-7 is a second generation observatory. It is about twice as large and heavy as its predecessors, giving it considerably greater capability for scientific measurements. This report reviews mission objectives, flight history, and scientific experiments; describes the observatory; briefly compares OSO-7 with the first six OSO's; and summarizes the performance of OSO-7.
Source record↗
Review of design and operational characteristics of the 0.3-meter transonic cryogenic tunnel
The past 6 years of operation with the NASA Langley 0.3 m transonic cryogenic tunnel (TCT) show that there are no insurmountable problems associated with cryogenic testing with gaseous nitrogen at transonic Mach numbers. The fundamentals of the concept were validated both analytically and experimentally and the 0.3 m TCT, with its unique Reynolds number capability, was used for a wide variety of aerodynamic tests. Techniques regarding real-gas effects were developed and cryogenic tunnel conditions can be set and maintained accurately. Cryogenic cooling by injecting liquid nitrogen directly into the tunnel circuit imposes no problems with temperature distribution or dynamic response characteristics. Experience with the 0.3 m TCT, indicates that there is a significant learning process associated with cryogenic, high Reynolds number testing. Many of the questions have already been answered; however, factors such as tunnel control, run logic, economics, instrumentation, and model technology present many new and challenging problems.
Ray, E. J.↗
Review of design and operational characteristics of the 0.3-meter transonic cryogenic tunnel
The fundamentals of cryogenic testing are validated both analytically and experimentally employing the 0.3-m transonic cryogenic tunnel. The tunnel with its unique Reynolds number capability has been used for a wide variety of aerodynamic tests. Techniques regarding real-gas effects have been developed and cryogenic tunnel conditions are set and maintained accurately. It is shown that cryogenic cooling, by injecting nitrogen directly into the tunnel circuit, imposes no problems with temperature distribution or dynamic response characteristics.
Ray, E. J.↗
Temperature structure in the lower atmosphere of Venus - New results derived from Pioneer Venus entry probe measurements
The Pioneer Venus Small-Probe Net Flux Radiometer temperature sensor and its calibration, the thermal model of the sensor head, the procedure for deriving atmospheric temperature from the sensor temperatures, and the new temperature results for each entry probe are reported. The new results are compared with those of the Small-Probe Atmospheric Structure experiment and with simple models of diurnal and latitudinal temperature contrasts. A dynamical inconsistency between these results and low-latitude measurements by the Sounder probe is described, and possible ways to resolve it are considered.
Sromovsky, L. A.↗
Active region flows
A wide range of observations has shown that active region phenomena in the photospheric, chromospheric and coronal temperature regimes are dynamical in nature. At the photosphere, recent observations of full line profiles place an upper limit of about + or - 20/msec on any downflows at supergranule cell edges. Observations of the full Stokes 5 profiles in the network show no evidence for downflows in magnetic flux tubes. In the area of chromospheric dynamics, several models were put forward recently to reproduce the observed behavior of spicules. However, it is pointed out that these adiabatic models do not include the powerful radiative dissipation which tend to damp out the large amplitude disturbances that produce the spicular acceleration in the models. In the corona, loop flows along field lines clearly transport mass and energy at rates important for the dynamics of these structures. However, advances in understanding the heating and mass balance of the loop structures seem to require new kinds of observations. Some results are presented using a remote sensing diagnostic of the intensity and orientation of macroscopic plasma electric fields predicted by models of reconnective heating and also wave heating.
Foukal, Peter↗
Thermal response of integral multicomponent composites to a high-energy aerothermodynamic heating environment with surface temperature to 1800 K
Laminated composite insulations developed for potential use on advanced spacecraft operating between GEO and LEO were tested in an aerothermodynamic environment simulating an AOTV aerobraking maneuver (altitude 82.3 km and velocity = 9.0 km/s). Comparisons are discussed between these data and predictions of in-depth temperature response using dynamical thermal conductivity values to 2000 K.
Stewart, David A.↗
Conserving approximations for strongly correlated electron systems - Bethe-Salpeter equation and dynamics for the two-dimensional Hubbard model
A semianalytical approach is described for strongly correlated electronic systems which satisfies microscopic conservation laws, treats strong frequency and momentum dependences, and provides information on both static and dynamic properties. This approach may be used to treat large systems and temperatures lower than those currently accessible to finite-temperature quantum Monte Carlo techniques. Examples of such systems include heavy-electron compounds, organic Bechegaard salts, bis-(ethylenedithiolo)-TTF superconductors, and the oxide superconductors. The technique is based on the derivation and self-consistent solution of infinite-order conserving approximations. The technique is used to derive a low-temperature phase diagram and dynamic correlation functions for the two-dimensional Hubbard lattice model.
Bickers, N. E.↗
The relation between ferroelasticity and superconductivity
The high-temperature superconductivity is explained widely by the layered crystal structure. The one- and two-dimensional subsystems and their interaction are investigated here. It is assumed that the high-T(sub c) superconductivity takes place in the two-dimensional subsystem and the increase of the phase transition temperature from 60 K up to 90 K is the consequence of turning on the influence of one-dimensional chains. The interaction between the two subsystems is transferred along the c axis by the phonons of breathing mode, which causes the hybridization of the electronic bonds between these subsystems. The experimental works indicate that the existence of both the chains Cu(1)-O and their interaction with the superconducting plane of Cu(2)-O modify the temperature of the transition to the superconducting state. It is seen from the neutron scattering data that the rates of the interatomic distance dependencies on temperature are changed around 140 K and 90 K. The 'zig-zag' order in Cu(1)-O chains has been postulated but, on the other hand, the vibrations with a large amplitude only were reported. The bi-stabilized situation of the oxygen ions can be caused by the change of distance between these ions and the Ba ions. It leads to the appearance of a two-well potential. Its parameters depend on temperature and the dynamics of the oxygen ions' movement. They can induce the antipolar order, which can be, however, more or less chaotic. The investigation of the ferroelastic properties of Y-Ba-Cu-O samples lead to the conclusion that they are related to jumps of ions inside the given chain and not to a diffusion between different sites in the ab plane. Researchers deduce thus that the fluctuating oxygen ions from these chains create dipoles in the ab plane. They can be described with the pseudo-spin formalism/ - Pauli matrices/. The system can be described with the Ising model. The pseudo-spins interact with phonons and influence the superconductivity in the second subsystem.
Molak, A.↗
O-ring gasket test fixture
An apparatus is presented for testing O-ring gaskets under a variety of temperature, pressure, and dynamic loading conditions. Specifically, this apparatus has the ability to simulate a dynamic loading condition where the sealing surface in contact with the O-ring moves both away from and axially along the face of the O-ring.
Turner, James Eric↗
Historical perspectives: The role of the NASA Lewis Research Center in the national space nuclear power programs
The history of the NASA Lewis Research Center's role in space nuclear power programs is reviewed. Lewis has provided leadership in research, development, and the advancement of space power and propulsion systems. Lewis' pioneering efforts in nuclear reactor technology, shielding, high temperature materials, fluid dynamics, heat transfer, mechanical and direct energy conversion, high-energy propellants, electric propulsion and high performance rocket fuels and nozzles have led to significant technical and management roles in many national space nuclear power and propulsion programs.
Bloomfield, H. S.↗
Mechanisms of atomic oxygen induced materials degradation
This paper includes discussions of mechanisms by which atomic oxygen may attack materials being flown in low earth orbit (LEO), suggestions for development of materials intrinsically resistant to the harsh LEO environment, and results of an Arrhenius fit to mass loss of Kapton under exposure to thermal atomic oxygen in a laboratory environment. Oxygen atoms are powerful oxidizing agents which can rapidly degrade many types of polymeric materials. The process details depend upon the specific material, its detailed bonding, the thermodynamic stability of potential products, temperature, and particle dynamics. With regard to spacecraft, many effects associated with atomic oxygen may be explained simply by ordinary thermal oxidation processes and by the fact that the oxygen has a preferred direction of impingement.
Pippin, H. G.↗
Historical perspectives - The role of the NASA Lewis Research Center in the national space nuclear power programs
The history of the NASA Lewis Research Center's role in space nuclear power programs is reviewed. Lewis has provided leadership in research, development, and the advancement of space power and propulsion systems. Lewis' pioneering efforts in nuclear reactor technology, shielding, high temperature materials, fluid dynamics, heat transfer, mechanical and direct energy conversion, high-energy propellants, electric propulsion and high performance rocket fuels and nozzles have led to significant technical and management roles in many natural space nuclear power and propulsion programs.
Bloomfield, H. S.↗
The relation between ferroelasticity and superconductivity
The high-temperature superconductivity is explained widely by the layered crystal structure. The one- and two-dimensional subsystems and their interaction are investigated here. It is assumed that the high-T(sub c) superconductivity takes place in the two-dimensional subsystem and the increase of the phase transition temperature from 60 K up to 90 K is the consequence of turning on the influence of one-dimensional chains. The interaction between the two subsystems is transferred along the c axis by the phonons of breathing mode, which causes the hybridization of the electronic bonds between these subsystems. The experimental works indicate that the existence of both the chains Cu(1)-O and their interaction with the superconducting plane of Cu(2)-O modify the temperature of the transition to the superconducting state. It is seen from the neutron scattering data that the rates of the interatomic distance dependencies on temperature are changed around 240 K and 90 K. The 'zig-zag' order in Cu(1)-O chains has been postulated but, on the other hand, the vibrations with a large amplitude only were reported. The bi-stabilized situation of the oxygen ions can be caused by the change of distance between these ions and the Ba ions. It leads to the appearance of a two-well potential. Its parameters depend on temperature and the dynamics of the oxygen ions' movement. They can induce the antipolar order, which can be, however, more or less chaotic. The investigation of the ferroelastic properties of Y-Ba-Cu-O samples lead to the conclusion that they are related to jumps of ions inside the given chain and not to a diffusion between different sites in the ab plane. Researchers deduce, thus, that the fluctuating oxygen ions from these chains create dipoles in the ab plane. They can be described with the pseudo-spin formalism (- Pauli matrices). The system can be described with the Ising model. The pseudo-spins interact with phonons and influence the superconductivity in the second subsystem.
Molak, A.↗
Develop advanced nonlinear signal analysis topographical mapping system
The SSME has been undergoing extensive flight certification and developmental testing, which involves some 250 health monitoring measurements. Under the severe temperature pressure, and dynamic environments sustained during operation, numerous major component failures have occurred, resulting in extensive engine hardware damage and scheduling losses. To enhance SSME safety and reliability, detailed analysis and evaluation of the measurements signal are mandatory to assess its dynamic characteristics and operational condition. Efficient and reliable signal detection techniques will reduce catastrophic system failure risks and expedite the evaluation of both flight and ground test data, and thereby reduce launch turn-around time. The basic objective of this contract are threefold: (1) Develop and validate a hierarchy of innovative signal analysis techniques for nonlinear and nonstationary time-frequency analysis. Performance evaluation will be carried out through detailed analysis of extensive SSME static firing and flight data. These techniques will be incorporated into a fully automated system. (2) Develop an advanced nonlinear signal analysis topographical mapping system (ATMS) to generate a Compressed SSME TOPO Data Base (CSTDB). This ATMS system will convert tremendous amounts of complex vibration signals from the entire SSME test history into a bank of succinct image-like patterns while retaining all respective phase information. A high compression ratio can be achieved to allow the minimal storage requirement, while providing fast signature retrieval, pattern comparison, and identification capabilities. (3) Integrate the nonlinear correlation techniques into the CSTDB data base with compatible TOPO input data format. Such integrated ATMS system will provide the large test archives necessary for a quick signature comparison. This study will provide timely assessment of SSME component operational status, identify probable causes of malfunction, and indicate feasible engineering solutions. The final result of this program will yield an ATMS system of nonlinear and nonstationary spectral analysis software package integrated with the Compressed SSME TOPO Data Base (CSTDB) on the same platform. This system will allow NASA engineers to retrieve any unique defect signatures and trends associated with different failure modes and anomalous phenomena over the entire SSME test history across turbo pump families.
Jong, Jen-Yi↗
Develop advanced nonlinear signal analysis topographical mapping system
The Space Shuttle Main Engine (SSME) has been undergoing extensive flight certification and developmental testing, which involves some 250 health monitoring measurements. Under the severe temperature, pressure, and dynamic environments sustained during operation, numerous major component failures have occurred, resulting in extensive engine hardware damage and scheduling losses. To enhance SSME safety and reliability, detailed analysis and evaluation of the measurements signal are mandatory to assess its dynamic characteristics and operational condition. Efficient and reliable signal detection techniques will reduce catastrophic system failure risks and expedite the evaluation of both flight and ground test data, and thereby reduce launch turn-around time. The basic objective of this contract are threefold: (1) develop and validate a hierarchy of innovative signal analysis techniques for nonlinear and nonstationary time-frequency analysis. Performance evaluation will be carried out through detailed analysis of extensive SSME static firing and flight data. These techniques will be incorporated into a fully automated system; (2) develop an advanced nonlinear signal analysis topographical mapping system (ATMS) to generate a Compressed SSME TOPO Data Base (CSTDB). This ATMS system will convert tremendous amount of complex vibration signals from the entire SSME test history into a bank of succinct image-like patterns while retaining all respective phase information. High compression ratio can be achieved to allow minimal storage requirement, while providing fast signature retrieval, pattern comparison, and identification capabilities; and (3) integrate the nonlinear correlation techniques into the CSTDB data base with compatible TOPO input data format. Such integrated ATMS system will provide the large test archives necessary for quick signature comparison. This study will provide timely assessment of SSME component operational status, identify probable causes of malfunction, and indicate feasible engineering solutions. The final result of this program will yield an ATMS system of nonlinear and nonstationary spectral analysis software package integrated with the Compressed SSME TOPO Data Base (CSTDB) on the same platform. This system will allow NASA engineers to retrieve any unique defect signatures and trends associated with different failure modes and anomalous phenomena over the entire SSME test history across turbo pump families.
Source record↗