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  • General Chemistry  (921)
  • Organic Chemistry  (720)
  • SPACE RADIATION  (435)
  • STRUCTURAL MECHANICS  (325)
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  • 1
    Publication Date: 2006-01-11
    Description: The Apollo 17 biological cosmic ray experiment to determine the effect of heavy cosmic ray particles on the brain and eyes is reported. The pocket mouse was selected as the biological specimen for the experiment. The radiation monitors, animal autopsy and animal processing are described, and the radiation effects on the scalp, retina, and viscera are analyzed.
    Keywords: SPACE RADIATION
    Type: NASA. Johnson Space Center Apollo 17 Prelim. Sci. Rept.; 14 p
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  • 2
    Publication Date: 2006-01-11
    Description: The ultraviolet spectrometer (UVS) onboard the Apollo 17 orbiting spacecraft was used to measure emissions from the lunar atmosphere. The UVS and calibration are discussed along with the lunar atmosphere observations and lunar albedo measurements.
    Keywords: SPACE RADIATION
    Type: NASA. Johnson Space Center Apollo 17 Prelimin. Sci. Rept.; 10 p
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  • 3
    Publication Date: 2006-01-11
    Description: The populations of interplanetary particles were studied by examining the energy spectra in a cosmic ray detector placed in the shade, facing away from the sun. Suprathermal ions of solar origin, and low-energy galactic cosmic rays are discussed.
    Keywords: SPACE RADIATION
    Type: NASA. Johnson Space Center Apollo 17 Prelim. Sci. Rept.; 5 p
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  • 4
    Publication Date: 2006-01-11
    Description: Glass track detectors were exposed to cosmic rays on the moon from December 11 to 13, 1972, during a period of relatively quiet sun activity as inferred from satellite proton counters. From 80 to 400 keV/amu, the differential flux of heavy cosmic ray nuclei decreases roughly as E to the -2nd power; this result together with the greater flux from the solar than the antisolar direction identify these nuclei as solar in origin.
    Keywords: SPACE RADIATION
    Type: NASA. Johnson Space Center Apollo 17 Prelim. Sci. Rept.; 4 p
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  • 5
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    In:  CASI
    Publication Date: 2006-04-05
    Description: The behaviour of the nonthermal electrons created at the impulsive phase of flares has been deduced from the microwave impulsive bursts and hard X-ray burst by many researchers. There is almost no doubt of the emission mechanisms that radio emissions are due to gyrosynchrotron emission and hard X-rays are collisional bremsstrahlung. However, there remain three controversial problems. One is whether the emission sources of the microwave impulsive burst and hard X-ray burst are common or not. Another is whether the injection of the nonthermal electrons into the source is impulsive or continuous. The other is the relation among the nonthermal electrons, soft X-rays, EUV flash, H-alpha kernels, and white light flares. These three problems are not independent of each other.
    Keywords: SPACE RADIATION
    Type: NASA, Washington High Energy Phenomena on the Sun; p 179-187
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  • 6
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    In:  CASI
    Publication Date: 2006-04-05
    Description: The production of solar flares by the reservoir of energy generated by sunspot magnetic fields is discussed. Electrons play an important part in the flare process since high energy electrons are responsible for X-ray and radio emission. The energy required in the form of protons trapped in sunspot magnetic fields to produce large solar flares is analyzed. A trigger mechanism is described where the particles can be rapidly dumped into the chromosphere when fast electrons are produced by Coulomb collisions and through pion production by the highest energy protons.
    Keywords: SPACE RADIATION
    Type: NASA, Washington High Energy Phenomena on the Sun; p 12-18
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  • 7
    Publication Date: 2006-03-28
    Description: Cybernetics diagnostics of machines and mechanisms using the spectral approach is discussed. The problem of establishing the accuracy of determination of the spectral composition is investigated. In systems with rectilinear or rotary movement, the vibrations appear in the form of movement rate vibrations, which are equivalent to frequency modulation of the signal, in proportion to the mean movement rate of the body. The case of a harmonic signal which reproduces and analyzes the characteristics of the frequency modulated signal is discussed. Mathematical models are developed to show the relationships of the parameters.
    Keywords: STRUCTURAL MECHANICS
    Type: Cybernetic Diagnostics of Mech. Systems with Vibro-acoustic Phenomena (NASA-TT-F-14899); p 275-278
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  • 8
    Publication Date: 2006-03-28
    Description: Free vibrations of a system and vibrations which are multiples of them in frequency are discussed. The corresponding periodic forced vibrations of the type n/m (n is the number of periods of disturbance between periods of movement and m is the number of periods of movement in one period of disturbance), generated by a harmonic or close to harmonic disturbance, are propagated close to the corresponding curves of the free vibrations and their frequency multiples. It has been proposed that investigation of transitional modes of motion and capture regions be carried out by precise methods in phase space, with the least number of coordinates. Thus, for example, for nonautonomous second order equations (for example, the Duffing equations), in place of three variables (coordinates, velocity, phases), it is proposed to use two: velocity during transition of the coordinate through zero and phase.
    Keywords: STRUCTURAL MECHANICS
    Type: Cybernetic Diagnostics of Mech. Systems with Vibro-acoustic Phenomena (NASA-TT-F-14899); p 256-259
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  • 9
    Publication Date: 2006-03-28
    Description: A numerical analysis of the transitional modes of motion for a vibroshock system was conducted. The capture regions of the system are emphasized. The three initial parameters for a nonautonomous vibroshock system with one degree of freedom are identified as: (1) coordinates, (2) velocity, and (3) time. Mathematical models are developed to show the relationship of the parameters. Graphs are included to show the nature of the capture regions and to portray the trajectory of motion of mass with time, by solution of differential equations during increase and decrease in time.
    Keywords: STRUCTURAL MECHANICS
    Type: Cybernetic Diagnostics of Mech. Systems with Vibro-acoustic Phenomena (NASA-TT-F-14899); p 250-255
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  • 10
    Publication Date: 2006-03-28
    Description: A solution is given to the problem of a transient vibration process in a fastened plate, during a sudden displacement of the edge. Some partial cases of excitation are examined in which the packing can be calculated and the explicit type of change in a deformation over time can be found. Some examples are presented.
    Keywords: STRUCTURAL MECHANICS
    Type: Cybernetic Diagnostics of Mech. Systems with Vibro-acoustic Phenomena (NASA-TT-F-14899); p 204-207
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  • 11
    Publication Date: 2006-03-28
    Description: The method of automatic identification of acoustical signals, by means of the segmentation was used to investigate noises and vibrations in machines and mechanisms, for cybernetic diagnostics. The structural analysis consists of presentation of a noise or vibroacoustical signal as a sequence of segments, determined by the time quantization, in which each segment is characterized by specific spectral characteristics. The structural spectrum is plotted as a histogram of the segments, also as a relation of the probability density of appearance of a segment to the segment type. It is assumed that the conditions of ergodic processes are maintained.
    Keywords: STRUCTURAL MECHANICS
    Type: Cybernetic Diagnostics of Mech. Systems with Vibro-acoustic Phenomena (NASA-TT-F-14899); p 179-180
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  • 12
    Publication Date: 2006-03-28
    Description: An experimental investigation for estimating the nonlinearity of a diagnostic object was carried out on a single-stage, spur gear reducer. The linearity of the properties of spur gearing (including the linearity of its mode of operation) was tested. Torsional vibrations of the driven wheel and transverse (to the meshing plane) vibrations of the drive wheel on its support were taken as the two outputs of the object to be analyzed. The results of the investigation showed that the degree of nonlinearity of a reducing gear is essentially connected with its operating mode, so that different mathematical models of it can correspond to different values of the system parameters.
    Keywords: STRUCTURAL MECHANICS
    Type: Cybernetic Diagnostics of Mech. Systems with Vibro-acoustic Phenomena (NASA-TT-F-14899); p 157-159
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  • 13
    Publication Date: 2006-03-01
    Description: The stability of equilibrium shapes of elastic systems is examined. Stability loss in the case of similar equilibrium shapes, the disappearance of stable equilibrium shapes, and the disappearance of any forms of equilibrium are discussed. The error made by Euler in analyzing stability loss is pointed out, and Mises' truss is used as an example of stability loss in the case of similar equilibrium shapes.
    Keywords: STRUCTURAL MECHANICS
    Type: Stability and Oscillation of Elastic Systems: Mod. Concepts, Paradoxes and Errors (NASA-TT-F-751); p 1-183
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  • 14
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    In:  CASI
    Publication Date: 2006-03-01
    Description: Problems of oscillations of linear systems are discussed, including systems with a fractional number of degrees of freedom as well as free oscillations of a cantilever in the field of centrifugal forces. Four methods of solving the problem of the action of periodic instantaneous impulses are presented. The Tacoma catastrophe is analyzed and used as an example of aeroelastic oscillations. Problems of nonlinear system oscillations include the vibration maintenance of rotation, the Sommerfeld effect, and self-oscillations of a quasi-system with dry friction.
    Keywords: STRUCTURAL MECHANICS
    Type: Stability and Oscillation of Elastic Systems: Mod. Concepts, Paradoxes and Errors NASA-TT-F-751); p 184-418
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  • 15
    Publication Date: 2006-04-05
    Description: A brief summary of the symposium is presented along with an outlook for developments in solar physics.
    Keywords: SPACE RADIATION
    Type: NASA, Washington High Energy Phenomena on the Sun; p 625-630
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  • 16
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    In:  CASI
    Publication Date: 2006-04-05
    Description: Meter-wave pulsations observed at Culgoora are discussed. The characteristics of recorded pulsation events are summarized.
    Keywords: SPACE RADIATION
    Type: NASA, Washington High Energy Phenomena on the Sun; p 589-593
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  • 17
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    In:  CASI
    Publication Date: 2006-04-05
    Description: Consideration is given to whether the modulation of low energy solar cosmic ray nuclei between the sun and earth can be so extreme that the fluxes observed at 1 AU imply (1) that the cosmic ray energy density in the solar atmosphere is comparable to the thermal energy density, and/or (2) that the cosmic ray intensity is sufficient in the solar atmosphere to produce detectable fluxes of secondary particles such as low energy positrons. It was found that such large modulation is compatible with observations, provided that the modulation occurrence is confined within a solar envelope lying within approximately 0.2 to 0.3 AU of the sun. There is, however, no compelling observational evidence to require that the modulation is this large.
    Keywords: SPACE RADIATION
    Type: High Energy Phenomena on the Sun; p 418-438
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  • 18
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    In:  CASI
    Publication Date: 2006-04-05
    Description: Type 3 solar bursts observed by OGO-5, below 600 kHz, were analyzed. Decay times were measured, and collisional decay times were computed for distances out to 1 AU. By fitting power functions to the computed and observed decay times, and using local plasma hypothesis, it was found that the ratio rho of computed observed values varies with heliocentric radial distance according to a power function rho = 3r to the 0.7th power, assuming fundamental emission, and rho = 2r to the 0.7th power, assuming second harmonic emission.
    Keywords: SPACE RADIATION
    Type: NASA, Washington High Energy Phenomena on the Sun; p 537-539
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  • 19
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    Publication Date: 2006-04-05
    Description: Large solar flares produce intense soft X-ray emission, indicating the existence of high temperature plasmas that coexist in time with the plasmas responsible for the normally observed brightenings in H-alpha. The time behavior of the X-ray flux, as revealed, for example, by ion chamber detectors on the series of Solrad monitoring satellites, appears to roughly mimic the intensity-time behavior of the H-alpha flare, insofar as start times, times of maximum flux, and approximate decay times are concerned. In recent years, soft X-ray spectra of both active regions and solar flares have been obtained by instruments flown on spacecraft such as the Orbiting Solar Observatory (OSO) series. The disbursing elements used were Bragg crystals, and in the 8 Angstrom region the resolution is typically approximately 1200. This paper discusses the observed characteristics of X-ray flare spectra and spectroscopic diagnostics for determining electron temperatures, electron densities, and departures from ionization equilibrium within the soft X-ray emitting plasma.
    Keywords: SPACE RADIATION
    Type: NASA, Washington High Energy Phenomena on the Sun; p 262-275
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  • 20
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    In:  CASI
    Publication Date: 2006-04-05
    Description: The theory of solar microwave bursts is discussed in terms of gyrosynchrotron emission and absorption in a magnetoactive plasma and other absorption processes by the background medium. Simplified formulas for all turnover frequencies are given. Above about 2 GHz the most likely absorption processes for large bursts are free-free absorption and gyrosynchrotron self-absorption. The former process is capable of producing flux densities which are flat or slowly varying functions of frequency. The latter process sets absolute upper limits on the intensities of microwave bursts, which at a given frequency, depend only on the magnetic field in the source region.
    Keywords: SPACE RADIATION
    Type: High Energy Phenomena on the Sun; p 188-197
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  • 21
    Publication Date: 2006-02-22
    Description: Energetic protons injected into interplanetary space in solar particle events can interfere with spacecraft operations and experiments and can cause permanent degradation of some components. For future long term interplanetary and planetary missions, techniques were developed which use solar particle event data from 1956 through 1970 to predict the probability of exceeding any value of peak proton intensity or mission proton fluence. Dependences on proton energy (near 10 to 100 MeV), heliocentric distance, and phase of the solar cycle are included. The techniques are described and applied to the Mariner Jupiter/Saturn 1977 mission.
    Keywords: SPACE RADIATION
    Type: JPL Quart. Tech. Rev., Vol. 3, No. 2 (NASA-CR-133863); p 37-44
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  • 22
    Publication Date: 2006-01-11
    Description: The Apollo 17 biostack experiment to establish the biological efficiency of individual heavy nuclei particles of galactic cosmic radiation are reported. The experiment theory, interaction of heavy nuclei particles with biologic matter, and the total dose of cosmic ionizing radiation are discussed along with the radiation effects of heavy nuclei on Artemia salina eggs, and Bacillus subtilis.
    Keywords: SPACE RADIATION
    Type: NASA. Johnson Space Center Apollo 17 Prelim. Sci. Rept.; 10 p
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  • 23
    Publication Date: 2006-01-11
    Description: Preliminary results are presented of data on the extent of the cosmic ray-induced activity obtained by a sodium iodide thallium-activated crystal flown onboard the Apollo 17 command module. Qualitative identification is reported for the following: Na-24, I-123, I-124, I-125, I-126, and Xe-127.
    Keywords: SPACE RADIATION
    Type: Apollo 17 Prelim. Sci. Rept.; 4 p
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  • 24
    Publication Date: 2006-01-11
    Description: The lunar surface cosmic ray experiment, consisting of sets of mica, glass, plastic, and metal foil detectors, was successfully deployed on the Apollo 17 mission. One set of detectors was exposed directly to sunlight and another set was placed in shade. Preliminary scanning of the mica detectors shows the expected registration of heavy solar wind ions in the sample exposed directly to the sun. The initial results indicate a depletion of very-heavy solar wind ions. The effect is probably not real but is caused by scanning inefficiencies. Despite the lack of any pronounced solar activity, energetic heavy particles with energies extending to 1 MeV/nucleon were observed. Equal track densities of approximately 6000 tracks/cm sq 0.5 microns in length were measured in mica samples exposed in both sunlight and shade.
    Keywords: SPACE RADIATION
    Type: NASA. Johnson Space Center Apollo 17 Prelim. Sci. Rept.; 9 p
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  • 25
    Publication Date: 2006-04-05
    Description: Curves of the number of type 3 bursts as a function of time are presented for six fixed frequencies (2.8, 1.65, 1.31, 0.995, 0.700, and 0.54 MHz). The curves peak at approximately 0500 UT August 20, 1968, and are symmetrical on both sides. Sakurai (1971) has shown that this time correlates well with the CMP of the McMath Region 9597. The maximum rate of bursts is approximately 150 per hour at the higher frequency of 2.8 MHz. Over 20,000 bursts were counted during the 15-day period from August 13 to August 27 when the active region was visible to the earth. A least-squares normal curve has been fitted to the observational data and calculations of variance and standard deviation are given.
    Keywords: SPACE RADIATION
    Type: NASA, Washington High Energy Phenomena on the Sun; p 552-557
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  • 26
    Publication Date: 2006-04-05
    Description: The propagation in the corona of the magnetohydrodynamic (MHD) disturbance possibly emitted at the explosive stage in the initial phase of a flare is considered. The behavior of the MHD fast-mode wavefront, whose source is located at the flare, is calculated by using eiconal-characteristic method in the High Altitude Observatory (HAO) realistic models of coronal magnetic field and density for the days of some particular flare events. It is shown as the result that the peculiar behavior of Moreton's surface wave and the peculiar appearance in the shape and position of the type 2 burst sources can be consistently understood by considering the refraction, focussing, and formation of shocks of MHD fast-mode disturbance in the actual distribution of Alfven velocity in the corona. Moreton waves seem to appear only when the flare explosion happens to occur at the edge of an active region and faces a low-Alfven-velocity region lying on the surface. The wave, which is initially emitted isotropically is refracted into a direction in which the condition for down-refraction holds to allow chromospheric reentrance of disturbance.
    Keywords: SPACE RADIATION
    Type: NASA, Washington High Energy Phenomena on the Sun; p 577-588
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  • 27
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    Publication Date: 2006-04-05
    Description: The use of solar flare models based on specific and detailed observations of solar flares is discussed. A process for determining the validity of various solar models is analyzed. The process relegates the infall-impact model for flares to a secondary role in high energy solar events. The strictly thermal infall-impact model cannot lead to temperatures greater than five million degrees K. Another process is needed to explain the high energy aspects of solar flares which are related to temperatures equal to or greater than 10 to the 7th power degrees K, nonthermal X-ray and radio emissions, white light flares, high energy particles from the sun, and gamma ray producing particles in the sun.
    Keywords: SPACE RADIATION
    Type: High Energy Phenomena on the Sun; p 19-25
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  • 28
    Publication Date: 2006-03-28
    Description: The problem is discussed of identification of a linear object of known structure, the movement of which is described by a system of differential equations of the type y = Ay + Bu, where y is an n-dimensional output vector, u is an m-dimensional vector of stationary, random disturbances (inputs), A and B are matrices of unknown parameters of the dimension, n x n and n x m, respectively. The spectral and reciprocal spectral densities of the inputs and outputs are used as the initial information on the object.
    Keywords: STRUCTURAL MECHANICS
    Type: Cybernetic Diagnostics of Mech. Systems with Vibro-acoustic Phenomena (NASA-TT-F-14899); p 139-141
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  • 29
    Publication Date: 2006-03-28
    Description: Radial and axial vibration measurements on the scanning disk and the data storage board of an optical-mechanical scanner are evaluated. Statistical processing of the observational data establishes the excitation source and determines the effect of disk torsional vibrations on the data storage board.
    Keywords: STRUCTURAL MECHANICS
    Type: Cybernetic Diagnostics of Mech. Systems with Vibro-acoustic Phenomena (NASA-TT-F-14899); p 105-106
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  • 30
    Publication Date: 2006-03-28
    Description: The torque of a drive shaft in a magnetic recording device was studied by oscillographic recordings. Statistical evaluation of the dynamic spectral densities showed that the principle source of disturbing forces is loading in the drive shaft radial play.
    Keywords: STRUCTURAL MECHANICS
    Type: Cybernetic Diagnostics of Mech. Systems with Vibro-acoustic Phenomena (NASA-TT-F-14899); p 103-104
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  • 31
    Publication Date: 2006-03-28
    Description: The equation of motion was used to examine the problem of vibrations of a thin elastic plate covered with a thin viscous layer. Mathematical formulation and the solution of the problem are given.
    Keywords: STRUCTURAL MECHANICS
    Type: Cybernetic Diagnostics of Mech. Systems with Vibro-acoustic Phenomena (NASA-TT-F-14899); p 89-90
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  • 32
    Publication Date: 2006-03-28
    Description: The statistical characteristics of complex variation amplitudes of shells excited by harmonic force sources in the sound frequency range are examined. Vibrations were measured with a multichannel unit, permitting the component values of a complex vibration amplitude for the i-th measurement point to be obtained at each measured point. An estimation was also made of the nature of the vibration field structure.
    Keywords: STRUCTURAL MECHANICS
    Type: Cybernetic Diagnostics of Mech. Systems with Vibro-acoustic Phenomena (NASA-TT-F-14899); p 68-73
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  • 33
    Publication Date: 2006-03-28
    Description: A traveling wave unit was built to process measurement data on spatial damping parameters and to simplify statistical treatment of the results. Mean values of the loss coefficient, lengths of flexual waves, and wave propagation velocities for a given set of discrete functions were determined. Results are given in a table.
    Keywords: STRUCTURAL MECHANICS
    Type: Cybernetic Diagnostics of Mech. Systems with Vibro-acoustic Phenomena (NASA-TT-F-14899); p 81-82
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  • 34
    Publication Date: 2006-03-28
    Description: A method is proposed for determining vibroacoustic characteristics from the results of measurements of the distribution of vibrational energy in a structure. The method is based on an energy model of a structure studied earlier. Equations are written to describe the distribution of vibrational energy in a hypothetical diffuse energy state in structural elements.
    Keywords: STRUCTURAL MECHANICS
    Type: Cybernetic Diagnostics of Mech. Systems with Vibro-acoustic Phenomena (NASA-TT-F-14899); p 74-77
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  • 35
    Publication Date: 2006-03-28
    Description: The distribution pattern of the amplitudes of vibrations, measured at various points on the surface of a shell, stimulated by a point source of harmonic force in the sound frequency range was studied experimentally. This pattern permits a valid spacing estimate to be carried out of the average structural characteristics of the vibrations, which are used for both estimation of the vibration excitability of the structure and for estimation of the effectiveness of use of a vibration-absorbing covering.
    Keywords: STRUCTURAL MECHANICS
    Type: Cybernetic Diagnostics of Mech. Systems with Vibro-acoustic Phenomena (NASA-TT-F-14899); p 61-67
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  • 36
    Publication Date: 2006-03-28
    Description: A method, developed for making measurements in reverberation chambers in the steady state mode, is reported. Spatial distribution patterns of the square of the sound pressure vs type of exciting signal were produced theoretically and checked experimentally in a reverberation chamber. Results of measurements of spatial irregularities of the field with pure tones and with noise bands in the 200 to 2,000 Hz frequency range were used for calculating statistical parameters of the reverbation fields by computer. The calculation program included determination of density probability function, integral distribution pattern, mathematical expectation, normalized dispersion of the mean square of the pressure.
    Keywords: STRUCTURAL MECHANICS
    Type: Cybernetic Diagnostics of Mech. Systems with Vibro-acoustic Phenomena (NASA-TT-F-14899); p 57-60
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  • 37
    Publication Date: 2006-03-28
    Description: Research was begun into the dynamic characteristics of wires, including the self-damping properties. A series of wire insulator fastenings, with and without dampers, was also developed.
    Keywords: STRUCTURAL MECHANICS
    Type: Cybernetic Diagnostics of Mech. Systems with Vibro-acoustic Phenomena (NASA-TT-F-14899); p 48-49
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  • 38
    Publication Date: 2006-03-28
    Description: Various calculation schemes were proposed for describing vibrations in a piping system with pulsating flow. Methods were selected and applied according to the type of irregularities examined: concentrated ones, extended ones, or complex ones. The selection of a method also depends on comparability of the extent of the irregularities with the pressure wavelength and velocity in the flow. Relations were found which permit a description of the interaction of a pulsating flow with any irregularity in the system. For complex systems with varying temperatures and some irregularities, relations were obtained, which reflect the varying phase displacement of the forces in these irregularities. The effect of the frictional torque on pipeline supports, in the presence of flexural and torsional vibrations was investigated, on the assumption that the frictional torque depends linearly on the angular velocity.
    Keywords: STRUCTURAL MECHANICS
    Type: Cybernetic Diagnostics of Mech. Systems with Vibro-acoustic Phenomena (NASA-TT-F-14899); p 51-52
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  • 39
    Publication Date: 2006-03-28
    Description: Certain characteristics of the reactions of typical skin panels of a passenger aircraft to acoustical loading are being investigated, for development of an objective method of diagnostics for skin condition, under the operations and maintenance sections of civil aviation. There are a number of difficulties connected with the solution of this problem. The reactions of skin panels exposed to the noises of the exhaust jets are dependent on the aircraft operating conditions, the geometric parameters and limiting conditions of the panels.
    Keywords: STRUCTURAL MECHANICS
    Type: Cybernetic Diagnostics of Mech. Systems with Vibro-acoustic Phenomena (NASA-TT-F-14899); p 41-43
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  • 40
    Publication Date: 2006-03-28
    Description: A program was compiled for calculating acoustical pressure levels, which might be created by vibrations of complex structures (an assembly of shells and rods), under the influence of a given force, for cases when these fields cannot be measured directly. The acoustical field is determined according to transition frequency and pulse characteristics of the structure in the projection mode. Projection characteristics are equal to the reception characteristics, for vibrating systems in which the reciprocity principle holds true. Characteristics in the receiving mode are calculated on the basis of experimental data on a point pulse space velocity source (input signal) and vibration response of the structure (output signal). The space velocity of a pulse source, set at a point in space r, where it is necessary to calculate the sound field of the structure p(r,t), is determined by measurements of acoustic pressure, created by a point source at a distance R. The vibration response is measured at the point where the forces F and f exciting the system should act.
    Keywords: STRUCTURAL MECHANICS
    Type: Cybernetic Diagnostics of Mech. Systems with Vibro-acoustic Phenomena (NASA-TT-F-14899); p 53-56
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  • 41
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    In:  CASI
    Publication Date: 2006-03-27
    Description: The differenced range versus integrated Doppler (DRVID) technique was used to study charged particle changes in the ray path between earth and Mariner 9. For plasma activity near the sun, DRVID data were obtained from August 10 to October 24, 1972, surrounding the Mariner 9 superior conjunction on September 7. If the records are viewed in terms of range change or range change rate, the day-to-day fluctuations in these quantities mask the changes expected due to the varying solar elongation. Thus, while the steady-state total electron content varies by a factor of 4, the columnar content changes show no systematic variations.
    Keywords: SPACE RADIATION
    Type: Mariner Mars 1971 Proj., Vol. 4; p 471-472
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  • 42
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    In:  CASI
    Publication Date: 2006-03-26
    Description: Lunar gamma ray spectra obtained during Apollo-15 and -16 flights show a natural radioactivity due to potassium, thorium, and uranium as well as a cosmic ray induced activity in the lunar surface due to high neutron interactions produced by (p,n) reaction in the lunar surface. The radioactivity is at a low in the highlands on the backside of the moon; most of the radioactivity is confined to the Oceanus Procellarum/Mare Imbrium region and to the Van de Graff area on the lunar backside.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci.; p 132-135
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  • 43
    facet.materialart.
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    In:  CASI
    Publication Date: 2006-03-26
    Description: Aluminum/silicon and magnesium/silicon concentration measurements along Apollo-15 and -16 lunar groundtracks by X-rays show that the highlands are very rich in aluminum, and that mare basalts cover large areas.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci.; p 127-131
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  • 44
    Publication Date: 2006-03-26
    Description: Spectrometric scans of faint optical emissions from interstellar gas are reported. Systematic variations along the galactic plane in both the intensity and radial velocity of the galactic H alpha suggest that the diffuse emission is strongly associated with three nearby galactic spiral arms.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci.; p 88-91
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  • 45
    Publication Date: 2006-03-26
    Description: Scientific goals and the instrumentation package for the OSO-K/solar flare mission are reported. The problem of determining origin and energetics of solar flares is considered.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci.; p 63-68
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  • 46
    Publication Date: 2006-03-26
    Description: Soft X-ray and hydrogen alpha observations on the structure of a solar flare show the typical flare behavior - a rapid rise to maximum and a gradual exponential decay, with good time correlation between the soft X-rays and H alpha. The emission is identified by Fe XI ion, and the emitting region is contoured on EUV maps.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci.; p 54-57
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  • 47
    Publication Date: 2006-03-26
    Description: The mechanism responsible for the modulation of synchrotron radiation in the meter wave range by a solar flare is examined. The proposed explanation is based on the interaction of a flare generated shock front with a magnetic flux tube extending out into the corona over the flare. As the shock wave propagates through the flux tube, Alfven waves are developing and travelling up the tube toward each other, thereby accelerating electrons and protons by the Fermi mechanism and thus filling the top of the flux tube with energetic electrons. Radial oscillations develop as the shock front becomes parallel to the magnetic field direction and the intensity of the synchrotron radiation is modulated by these oscillations. An OSO-5 experiment detected a hard X-ray burst associated with the flare that produced modulated radio emission and X-ray modulations that are attributed to density fluctuations in the X-ray bursts.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci.; p 49-53
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  • 48
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    In:  CASI
    Publication Date: 2006-03-26
    Description: The structure of an isolated solar flare point observed by vacuum telescope and multichannel spectrophotometer is considered. The tiny bright spot in H alpha photos lasted less than 30 seconds and coincided with a Type-III solar burst; a soft X-ray burst peaked at the time of this event. The small scale structure of the flare point exhibited in miniature the characteristics of a true flare event.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci.; p 58-62
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  • 49
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    In:  CASI
    Publication Date: 2006-03-26
    Description: Solid state low-energy telescopic observations on solar and galactic cosmic rays from 2 AU outward by satellites are evaluated. Plots of solar events leading to large injections of particles from the sun show that low energy slower protons arrive first by many hours before the higher energy protons, and that the higher energy particles are falling off more rapidly.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci.; p 38-44
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  • 50
    Publication Date: 2006-03-26
    Description: Variation of the cosmic ray intensity as a function away from the sun and its radial derivative is studied by plotting satellite cosmic ray measurements against sea level neutron monitor data. Results show that the solar modulation cavity extends well beyond 2 AU and that irregularities in the sun's magnetic field are carried outward radially by the solar wind, thus sweeping low energy cosmic rays out of the solar system and at the same time cooling cosmic rays reaching the earth.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci.; p 45-48
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  • 51
    Publication Date: 2006-03-26
    Description: Cosmic ray electron measurements by individual threshold detector elements show that about 30 percent of observed electron-like galactic cosmic showers are really proton initiated events. The cosmic electron spectrum at about 10 GeV exhibits a consistent dropoff in intensity leading to a best fit at a power law of spectral index -3.2; a break in the spectrum should occur above 10 GeV.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci.; p 24-28
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  • 52
    Publication Date: 2006-03-26
    Description: Explorer satellite observations of modulations in the cosmic ray spectrum during the entire period of the solar cycle show intensity variations in the proton and alpha modulated spectra. A positive correlation between plasma density and variation in cosmic ray intensity is found that breaks during the transition period when higher energy intensity is decreasing as the solar activity increases. It is suggested that the alpha particles lead the proton particles during transition periods and thus make the lag time shorter for high rigidity near the solar maximum and the solar minimum.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci.; p 34-37
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  • 53
    Publication Date: 2006-03-26
    Description: Observations of a quiet-time interplanetary electron component in the 20 keV to 2 MeV energy range are reported. The measurements fill in the gap between the highest-energy known solar wind and the lowest-energy previously observed electron populations, and connect for the first time the entire solar-quiet interplanetary electron spectrum over a dynamic range of nearly 10 to the 12th power in energy.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci.; p 29-33
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  • 54
    facet.materialart.
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    In:  CASI
    Publication Date: 2006-03-26
    Description: A theoretical model in the form of a three-dimensional Monte Carlo calculation is developed that starts with known cosmic ray flux at the top of the atmosphere and follows particles as they interact with the atmosphere for a schematic representation of how atmospheric secondary gamma rays are produced. The model predicts atmospheric secondary gamma radiation as a function of altitude, energy, and zenith angle.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci.; p 16-19
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  • 55
    Publication Date: 2006-03-26
    Description: Charge and particle trajectory measurements during a balloon-borne experiment observing the composition of cosmic rays, are interpreted by plotting differential intensities of various nuclei of both primary and secondary origin above 3 GeV/nucleon. The large spectral difference between carbon plus oxygen and iron is confirmed in the difference between their secondary products. This large difference cannot be explained as being solely due to propagation effects and it is concluded that preferential acceleration of heavy nuclei due to a source effect is present.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci.; p 20-23
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  • 56
    facet.materialart.
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    In:  CASI
    Publication Date: 2006-03-26
    Description: Balloon observations of a low energy flux line at 2 x 0.001 photons cm/2 s/1 from the galactic center region around 470 keV are interpreted as the positron annihilation radiation that occurs on the surface of old neutron stars and is redshifted by their gravitational fields. An astrophysical model is formulated to explain the observed flux that provides for about 0.2 neutron stars per 3 x 10 to the 49th power cubic meters assuming that the disk thickness is about 1.5 x 10 to the 19th power meters.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci.; p 9-11
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  • 57
    Publication Date: 2006-04-05
    Description: In two recent papers it was shown that the metric type 3 emission is closely related to a transient perturbation seen in absorption in the H alpha line. In addition, this perturbation sometimes triggers a flare, sometimes not. This can explain why the type 3 have a poor H alpha flare correlation rate and still are a typical flash phase emission when flare-associated. The characteristics are summarized of the new association proposed. It is assumed that 10 to 100 keV electrons are accelerated in connection with a particular kind of transient H alpha absorbing feature. For as yet undetermined reasons, this process would often, but not always, result in a more efficient acceleration coincident with the early phase of the optical flare. The possibilities that this process could lead occasionally to long lasting subrelativistic particle emissive region are explored.
    Keywords: SPACE RADIATION
    Type: NASA, Washington High Energy Phenomena on the Sun; p 615-622
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  • 58
    Publication Date: 2006-04-05
    Description: The following new hypothesis is proposed. The decay time of plasma waves is much shorter than the time scale of type 3 bursts especially at low frequencies. Accordingly, the time variation of radio flux at a given frequency merely corresponds to the flux of fast electrons passing through the corresponding plasma layer.
    Keywords: SPACE RADIATION
    Type: NASA, Washington High Energy Phenomena on the Sun; p 573-576
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  • 59
    facet.materialart.
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    In:  CASI
    Publication Date: 2006-04-05
    Description: The present state of the theory of type 3 bursts is reviewed by dividing the problem into the exciting agency, radiation source, and propagation of radiation between the source and the observer. In-situ measurements indicate that the excitors are electron streams of energy about 40 keV which are continuously relaxing. An investigation of neutralization of an electron stream indicates that n sub s is much less than 100,000 n sub e, where n sub s is the stream density and n sub e the coronal electron density. In situ observations are consistent with this result. An analysis of propagation of electrons in the current sheets of coronal streamers shows that such propagation at heights greater than 1 solar radius is impossible. The mechanisms for radiation are reviewed; it is shown that fundamental radiation at high frequencies (approximately 100 MHz) is highly beamed in the radial direction and that near the earth second harmonic radiation must be dominant. Because of beaming of the fundamental at high frequencies, it can often be quite weak near the limb so that the second harmonic is dominant. In considering propagation to the observer, the results of scattering of radiation are discussed. The present state of the theory of type 2 bursts is reviewed in the same manner as type 3 bursts.
    Keywords: SPACE RADIATION
    Type: NASA, Washington High Energy Phenomena on the Sun; p 558-572
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  • 60
    Publication Date: 2006-04-05
    Description: Analysis of data from the soft X-ray proportional counter spectrometer on OSO-4 has been continued along the lines of earlier work. It was noticed that the time profiles of X-ray counts from the OSO-4 instrument's 1 to 3 Angstrom detectors for two events showed a very rapid initial decay after maximum, followed by a much more slowly falling section. At least in the case of the larger of the two events, the change of slope seems quite definitely to be discontinuous. Temperatures and emission measures for both flares have been derived, by fitting an emission function to eight-channel count histograms which form the output of the 1 to 3 Angstrom detectors, analyzed into eight energy intervals by pulse-height analysis. The computer program is described. It employs temperature and continuum emission measures in the Culhane-Acton formula and the flux in the 6.7 KeV iron-line feature as free parameters, adjusting them by small amounts in successive iterations until the original historgram is approximately reproduced. A chi-squared is used to examine the agreement between histograms and terminates the iteration accordingly. Account is taken of the proportional counters' energy resolution in the fitting process.
    Keywords: SPACE RADIATION
    Type: High Energy phenomena on the Sun; p 276-282
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  • 61
    Publication Date: 2006-04-05
    Description: The theory of gamma-ray line emission from solar flares is reviewed and revised. It is shown that the line emissions at 0.5, 2.2, 4.4, and 6.1 MeV are due to positron annihilation, deuterium deexcitation following neutron capture on hydrogen, and the deexcitation of excited states in carbon and oxygen. From the observed relative line intensities it is possible to determine the spectrum of accelerated protons in the flare region. This spectrum is found to be very similar to that of charged particles from the flare observed near earth. The total number of protons at the sun is deduced from the observed absolute line intensities for various interaction models.
    Keywords: SPACE RADIATION
    Type: High Energy Phenomena on the Sun; p 301-314
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  • 62
    Publication Date: 2006-03-28
    Description: Endless structures are realized in practice, in the presence of loss and to an adequate extent, owing to which, reflections from the edges to the center part of the structure can be disregarded. In the absence of losses, reflections from the boundary frequently have to be taken into account. In this case, besides compensation for waves passing through the boundary, the reciprocal connection system can be used for compensation of the total field ahead of the boundary. In these cases, the system converters can be located in a different manner relative to the boundary and to one another. Each of the locations has inherent peculiarities, which must be taken into account in solving specific problems.
    Keywords: STRUCTURAL MECHANICS
    Type: Cybernetic Diagnostics of Mech. Systems with Vibro-acoustic Phenomena (NASA-TT-F-14899); p 222-228
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  • 63
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    In:  CASI
    Publication Date: 2006-03-28
    Description: The vibration characteristics of an unidimensional structure are discussed. The cases considered are: (1) a rigid pipe in which a wave propagates, (2) an infinite string along which a transverse wave propagates, (3) a rod along which longitudinal or torsional columns propagate, and (4) generally a unidimensional propagation of some one mode of vibrations which is nondegenerating with distance. Mathematical models are developed to show the performance of the mechanical devices under various damping conditions.
    Keywords: STRUCTURAL MECHANICS
    Type: Cybernetic Diagnostics of Mech. Systems with Vibro-acoustic Phenomena (NASA-TT-F-14899); p 216-221
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  • 64
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    In:  Other Sources
    Publication Date: 2011-08-16
    Description: Description of a variable step incremental procedure for the solution of nonlinear equations in finite element structural analysis. The proposed procedure is effective in improving the accuracy of the basic incremental technique and in providing, in addition, an accurate estimate of the discretization error. The proposed approach is highly appropriate for solving problems for which the user has no a priori estimate of the step size to use.
    Keywords: STRUCTURAL MECHANICS
    Type: International Journal for Numerical Methods in Engineering; 7; 4, 19; 1973
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  • 65
    Publication Date: 2011-08-16
    Description: Numerical solutions are presented for the problem of minimum weight design of a thin one-dimensional, simply supported, solid panel in compression, with one side exposed to a parallel high supersonic air flow. The flutter speed is held fixed and a minimum thickness constraint is imposed.
    Keywords: STRUCTURAL MECHANICS
    Type: International Journal for Numerical Methods in Engineering; 7; 4, 19; 1973
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  • 66
    Publication Date: 2011-08-16
    Keywords: SPACE RADIATION
    Type: Nature Physical Science; 246; Dec
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  • 67
    Publication Date: 2011-08-16
    Description: A series of solar flares accompanying type II and type IV radio bursts were observed while the active region McMath No. 9740 was on the solar disk. Most of these flares were also associated with solar cosmic rays and SSC geomagnetic storms. The expansion pattern of these disturbances near the earth's orbit is considered. This pattern appears to be useful for studying the propagation of interplanetary shock waves which are generated by solar flares.
    Keywords: SPACE RADIATION
    Type: Nature Physical Science; 246; Dec. 3
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  • 68
    Publication Date: 2011-08-16
    Description: Individual particles were analyzed on the collection screens in a Jeolco scanning electron microscope using a Kevex Li-drifted silicon energy dispersive X ray detector. It was found that the bulk of the stratospheric samples studied comes from explosive squib devices. It is pointed out that this finding does not invalidate the extensive results obtained by Bigg et al. (1970, 1971) in previous sampling experiments.
    Keywords: SPACE RADIATION
    Type: Journal of Geophysical Research; 78; Nov. 20
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  • 69
    Publication Date: 2011-08-16
    Description: The expected flux of K alpha line emission from sulfur, argon, calcium, and iron is calculated during both thermal and nonthermal solar X-ray events. Such emission is shown to be weak during the course of most of the nonthermal hard X-ray bursts that Kane and Anderson (1970) have observed. If Compton backscattering is significant at high energies, the flux is reduced still further for disk flares, but it is noted that the strong, near-limb burst of June 26 would have produced about 100 photons /sq cm/sec of sulfur and iron K alpha emission. The impulsive hard X-ray bursts may in general be too short-lived for much K alpha emission. It may be noted that sulfur K alpha emission in particular depends sensitively on the lower-energy limit of the nonthermal electron spectrum, assuming such a sharply defined boundary exists. During soft X-ray bursts, when temperatures of a few 10 to the 7th power K are obtained, K alpha emission from certain iron ions, specifically Fe XVIII-XXIII, may be important.
    Keywords: SPACE RADIATION
    Type: Solar Physics; 32; Sept
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  • 70
    Publication Date: 2011-08-16
    Description: The stability of the low-frequency waves propagating transverse to the magnetic field of a plasma composed of electrons, protons, and alpha particles with anisotropic electron and ion temperatures is explored. The threshold for the ordinary mode instability and the growth rates have a very strong dependence on the electron temperature anisotropy but have a comparatively weaker dependence on the ion temperature anisotropy, on the relative abundance of helium to hydrogen, and on the relative streaming of two ion species. The threshold for the instability of these low-frequency waves is (m sub e/m sub p) to the 1/2 power times smaller than the one corresponding to high-frequency waves; however, for a relative abundance of helium to hydrogen up to 20% for the relevant known magnetic fields, particle densities, temperatures, and drifts, the solar wind remains below the threshold for this instability.
    Keywords: SPACE RADIATION
    Type: Journal of Geophysical Research; 78; Dec. 1
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  • 71
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    Publication Date: 2011-08-16
    Description: The philosophy of fracture mechanics is reviewed and utilized to formulate a simplified approach to the determination of the stress-intensity factor photoelastically for three-dimensional problems. The method involves a Taylor Series correction for the maximum in-plane shear stress (TSCM) and does not involve stress separation. The results are illustrated by applying the TSCM to surface flaws in bending fields. Other three-dimensional problems solved by the TSCM are cited.
    Keywords: STRUCTURAL MECHANICS
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  • 72
    Publication Date: 2011-08-16
    Keywords: SPACE RADIATION
    Type: Solar Physics; 31; July 197
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  • 73
    Publication Date: 2011-08-16
    Description: Recent calculations suggest that three of the Galilean satellites are very effective in limiting the fluxes of energetic electrons and protons diffusing inward from Jupiter's outer magnetosphere. Electron and proton densities with and without lunar effects are plotted as functions of the distance from the center of the planet in units of Jupiter radii. Both electrons and protons in the model come from the solar wind. The trajectory of Pioneer 10 in magnetic coordinates is examined and the period of greatest danger to the spacecraft is discussed.
    Keywords: SPACE RADIATION
    Type: Science; 182; Dec. 7
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  • 74
    Publication Date: 2011-08-16
    Description: Fundamental characterization of the constant-amplitude fatigue crack propagation is achieved by an analysis of the rate of change of crack length with change in number of applied loading cycles, defining the rate values such that they are consistent with the basic assumption of smoothness and continuity in the fatigue crack growth process. The technique used to satisfy the analytical conditions and minimize the effects of local material anomalies and experimental errors is that of fitting a smooth curve to the entire set of basic data by least square regression. This yields a well-behaved function relating the number of cycles to the crack length. By taking the first derivative of the function, the crack growth rate is obtained for each point. The class of curve fitting functions used in the analysis is the polynomial of degree n.
    Keywords: STRUCTURAL MECHANICS
    Type: International Journal of Fracture; 9; Mar. 197
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  • 75
    Publication Date: 2011-08-16
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 185; Nov. 1
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  • 76
    Publication Date: 2011-08-16
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 186; Dec. 15
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  • 77
    Publication Date: 2011-08-16
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 186; Dec. 15
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  • 78
    Publication Date: 2011-08-16
    Description: The dependence of the thickness of the helium-enriched shell on the longitudinal position of the parent flares is considered along with the large-scale configuration of the expanding shell in interplanetary space. It is found that shock waves, magnetic bottles, and helium-enriched shells appear to expand eastwards of the meridian plane which crosses the flare region. It seems that the formation of the observed pattern of the shells is influenced by the interplanetary magnetic field between the sun and the earth.
    Keywords: SPACE RADIATION
    Type: Nature Physical Science; 246; Dec. 3
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  • 79
    Publication Date: 2011-08-16
    Description: This paper gives an overview of the development and status of an improved numerical process for the solution of solid mechanics problems. The proposed process uses a mixed formulation with the fundamental unknowns consisting of both stress and displacement parameters. The problem is formulated either by means of first-order partial differential equations or in a variational form by using a Hellinger-Reissner-type mixed variational principle. For presentation purposes, the components of a numerical process are characterized and the criteria for an ideal process are outlined. Commonly used finite-difference and finite-element procedures are examined in the light of these criteria and it is shown that they fall short in a number of ways. The proposed numerical process, on the other hand, satisfies most of the optimality criteria and appears to be particularly suited for use with the forthcoming generation computers.
    Keywords: STRUCTURAL MECHANICS
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  • 80
    Publication Date: 2011-08-16
    Description: Evaluation of OSO-5 measurements of the energy spectrum of the diffuse component of the cosmic X-ray flux in the energy range from 14 to 200 keV. A detailed description is given of the X-ray detector employed and of the method of selection and pulse-height analysis of X-ray events. The method employed in eliminating noncosmic X-ray contributions to the total counting rate is discussed. The final energy spectrum is found to be best fitted by a power law which is in essential agreement with that obtained from OSO-3 by Schwartz et al. (1970), in spite of what is regarded as an erroneous correction procedure used by them. In particular, it is suggested that the break in the energy spectrum at 40 keV which they reported may have been produced by an erroneous correction for the radioactivity induced in the detector during each passage through the intense charged-particle fluxes in the South Atlantic Anomaly.
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 186; Nov. 15
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  • 81
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    Publication Date: 2011-08-16
    Description: The purpose of this paper is to develop a sufficiently accurate analysis, which is much simpler than exact three-dimensional analysis, for statics and dynamics of composite laminates. The governing differential equations and boundary conditions are derived by following a variational approach. The displacements are assumed piecewise linear across the thickness and the effects of transverse shear deformations and rotary inertia are included. A procedure for obtaining the general solution of the above governing differential equations in the form of hyperbolic-trigonometric series is given. The accuracy of the present theory is assessed by obtaining results for free vibrations and flexure of simply supported rectangular laminates and comparing them with results from exact three-dimensional analysis.
    Keywords: STRUCTURAL MECHANICS
    Type: Journal of Sound and Vibration; 30; Oct. 22
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  • 82
    Publication Date: 2011-08-16
    Description: A balloon-borne measurement of the cosmic ray electron spectrum from 10 to 200 GeV is reported in which two new techniques have been used to remove proton background contamination. First, the depth of the spectrometer was more than 40 radiation lengths, the equivalent of more than 3 mean free paths of material, enabling hadronically and electromagnetically induced cascades to be differentiated for a subset of the data. Second, electromagnetic cascade starting points were determined to within plus or minus 0.1 radiation lengths on the basis of a calibration with electrons from 5.4 to 18 GeV at the Stanford Linear Accelerator, greatly reducing the chances for a proton to simulate an electron. The resulting spectrum, when fitted with a power law, is quite steep, -3.2 plus or minus 0.1, but the fit to a power law is marginal.
    Keywords: SPACE RADIATION
    Type: Journal of Geophysical Research; 78; Nov. 1
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  • 83
    Publication Date: 2011-08-16
    Description: We have observed a chromospheric brightening in the H alpha and Ca II K lines with a diameter of about 1 arc second. The time structure of this event, obtained with a relative resolution of 1 second, shows the rise time to be 4 seconds, the lifetime (FWHM) to be 20 seconds, and the decay time to be 5 seconds. This imposes new constraints on flare-point models. These restrictions can be accommodated easily by either an infall-impact flare model or a model invoking the precipitation of high-energy particles from the corona.
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 185; Nov. 1
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  • 84
    Publication Date: 2011-08-16
    Description: Abundances and isotopic compositions of He, Ne, Ar, and Xe have been measured in eight recently fallen chondrites. Ratios of concentrations of cosmic ray-produced He-3, Ne-21, Ne-22, and Ar-38 indicate that all eight samples experienced less than average cosmic ray shielding. He-3 and Ne-21 exposure ages were calculated using shielding corrected chondritic production rates and the measured Ne-22/Ne-21. Exposure ages calculated from Na-22/Ne-22 and Al-26/Ne-21 ratios and constant relative production rates show a bias between the two ages due to variations in Na-22/Al-26. Arguments are presented that this bias is due to irradiation hardness differences, and therefore the use of constant values for both the Na-22/Ne-22 and Al-26/Ne-21 production ratios is not permitted.
    Keywords: SPACE RADIATION
    Type: Geochimica et Cosmochimica Acta; 37; Nov. 197
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  • 85
    Publication Date: 2011-08-16
    Description: Results of measurements by a balloon-borne ionization spectrometer of the energy dependence of high-energy cosmic-ray charge composition. The results presented are greatly improved over those obtained earlier by Ormes et al. (1971) by the use of a multidimensional charge analysis with more efficient background rejection, and a more accurate energy determination. Complex couplings between the charge, energy, and trajectory information were taken into account and are discussed. The spectra of individual elements up to oxygen and of groups of nuclei up through iron were measured up to almost 100 GeV per nucleon. The energy spectrum of the secondary nuclei, B + N, is found to be steeper than that of the primary nuclei, C + O, in agreement with Smith et al. (1973). The most dramatic finding is that the spectrum of the iron nuclei is flatter than that of the carbon and oxygen nuclei by 0.57 plus or minus 0.14 of a power.
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 186; Nov. 15
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  • 86
    Publication Date: 2011-08-16
    Description: A list of emission lines in the spectra of solar flares between 6 and 25 A has been compiled using data obtained with a KAP crystal spectrometer on the OSO-5 satellite. The emission lines have been classified according to their sensitivity to flare activity. This classification provides a method for discriminating between iron in high stages of ionization (Fe XX-Fe XXV) and lower stages (Fe XVII-Fe XIX), the lines of which are both present in the same spectral region during flares. Identifications consistent with these classifications are proposed. Anomalous intensities in the spectra of Fe XVII and Fe XX are pointed out, and implications of the observations for models of the X-ray emitting regions are discussed.
    Keywords: SPACE RADIATION
    Type: Solar Physics; 31; July 197
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  • 87
    Publication Date: 2011-08-16
    Description: Certain results regarding the ratio of cosmic-ray sources (CRS) and Solar System abundances are the same as those obtained from explosive nucleosynthesis. Such a model is consistent with the fact that in the Solar System Mg, Si, and Fe are believed to be produced by explosive nucleosynthesis, whereas C and O are mainly products of other processes. The model considered explains the carbon-to-oxygen ratio in the cosmic rays.
    Keywords: SPACE RADIATION
    Type: Nature Physical Science; 246; Nov. 26
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  • 88
    Publication Date: 2011-08-16
    Description: Knowledge of the total gamma-ray production rate per H atom from the decay of neutral pions produced in interstellar cosmic-ray interactions is essential for determining the possible amount of interstellar H2. This production rate is recalculated here using the latest accelerator data on neutral pion production in p-p interactions up to about 1500 GeV. A simple but accurate approximation used here resolves the past disagreement over the magnitude of this rate. An upper limit is obtained of (1.51 plus or minus 0.23) times 10 to the -25th power/sec, consistent with the observed upper limit of 1.6 times 10 to the -25th power/sec.
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 185; Oct. 15
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  • 89
    Publication Date: 2011-08-16
    Description: Analytical and experimental data on the vibration characteristics of cantilevered winglike flat trapezoidal aluminum plates are presented. The plates had been reinforced with boron-epoxy composite material which had been placed symmetrically about the plate middle surface. The effect of filament orientation on the mode shapes and frequencies of the first ten modes and on the damping coefficients of several of the lowest frequency modes has been investigated experimentally. Experimental data are compared with results from a finite-element analysis. Stiffness properties of the composite material for use in the analysis were determined from vibration tests of composite reinforced aluminum beams.
    Keywords: STRUCTURAL MECHANICS
    Type: Journal of Composite Materials; 7; July 197
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  • 90
    Publication Date: 2011-08-16
    Description: The Neuber stress-concentration relation for notches in an elastic-plastic material subjected to shear loading was generalized for a crack in a finite plate subjected to tensile loading. An equation was derived which related the linear elastic stress-intensity factor, the applied stress, and two material parameters. The equation was then used as a two-parameter fracture criterion for surface- and through-cracked specimens. Fracture data from the literature on surface- and through-cracked sheet and plate specimens of steel, titanium alloy, titanium weldment, and aluminum alloy tested at room and cryogenic temperature were analyzed according to the proposed equation. For surface cracks, wide ranges of crack-depth to crack-length ratio and crack-depth to specimen-thickness ratio were considered. For through cracks, wide ranges of crack length and specimen width were also considered.-
    Keywords: STRUCTURAL MECHANICS
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  • 91
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2011-08-16
    Description: Two shock-like structures (i.e., abrupt step-like increases in number density, bulk speed, and proton temperature) were found in the data from Mariner 5 at 0.98 AU on June 26 and at 0.85 AU on Aug. 29, 1967. The thickness of these 'structures' determined from the magnetic field data was more than 1000 proton Larmor radii. They were also observed by Explorer 33, 34, and 35 at 1 AU, where the thicknesses were much smaller than in the Mariner 5 data. It is suggested that these two structures were nonlinear magnetoacoustic waves that were in the processes of steepening. It is further suggested that shocks would be formed just beyond 1 AU. These structures were not associated with corotating streams, but they could be associated with impressive solar events in which a flare was followed by type 2 and type 4 radio emission and a rare chromospheric wave.
    Keywords: SPACE RADIATION
    Type: Journal of Geophysical Research; 78; Sept. 1
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  • 92
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2011-08-16
    Description: The possible acceleration of heavy ions by the resonance scattering of radiation near bright stellar objects is examined. Planck spectra are assumed. At any radiation temperature, heavy-ion energies are found to be limited by aberration and Doppler effects. Photoionization is found to limit maximum radiation temperatures and energies for each ion. Collisional ionization by ambient electrons and ions may further limit heavy-ion energies. Because of these limitations, the production of the more energetic cosmic rays by this mechanism appears to be very improbable. If supernova radiation temperatures are high enough, they may produce heavy ions with energies up to several hundreds of MeV per nucleon. O and B stars appear to be able to accelerate certain heavy ions to 200 and 80 MeV per nucleon, respectively.
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 184; Sept. 1
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  • 93
    Publication Date: 2011-08-16
    Description: A problem in the linear theory of elasticity is considered wherein a layer with a circular cylindrical hole is subjected to a nonuniform axisymmetric radial displacement. The solution utilizes Navier's equations of elasticity which are solved by means of extended Hankel transforms. A special case in which the radial displacement is a linear function of the axial coordinate is presented. Numerical results are given in graphical form for the case when hole radius and layer thickness are equal. The inversion integrals were evaluated numerically using Longman's technique for computing infinite integrals of oscillatory functions.
    Keywords: STRUCTURAL MECHANICS
    Type: Acta Mechanica; 17; 1-2,; 1973
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  • 94
    Publication Date: 2011-08-16
    Description: A sensitive measurement by rocket-borne detectors of the X-ray flux from Cas A has revealed a steep continuum and a broad spectral feature in the region where line radiation from iron nuclei would be expected. The flux in this feature is 0.0122 plus or minus 0.0017 photons per sq cm per sec. The presence of broad iron lines is consistent with a model in which about 13 MeV-per-nucleon iron nuclei charge exchange with surrounding interstellar oxygen and other heavy atoms. The model suggests that a substantial fraction of the energy from the outburst has gone into low-energy cosmic rays which produce the observed H II region surrounding the remnant.
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 184; Aug. 15
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  • 95
    Publication Date: 2011-08-16
    Description: On October 15-16, 1970, we carried out balloon X-ray observations from Australia at energies above 15 keV. We present the high-energy X-ray spectra of three sources discovered by us, GX 301-2, GX 304-1, and GX 1 + 4. The data suggest that these high-energy sources correspond to the sources 2U 1223-62, 2U 1258-61, and 2U 1728-24 respectively. We also present the spectra for two additional sources, GX 5-1 (2U 1757-25) and GX 3 + 1 (2U 1744-26). The average intensity of the highly variable source GX 301-2 was observed to be as great as Tau X-1 in the energy range 15-50 keV.
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 184; Aug. 15
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  • 96
    Publication Date: 2011-08-16
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 184; Aug. 15
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  • 97
    facet.materialart.
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    In:  Other Sources
    Publication Date: 2011-08-16
    Description: A simple, inexpensive method for studying slow crack growth is described. The method entails measurements of load relaxation at constant displacement using a double torsion specimen. It is demonstrated that the data generated using this technique are in excellent agreement with data obtained using the more complex conventional techniques, for a range of materials - steel, titanium, glass, aluminum oxide, PMMA. These encouraging initial results suggest that additional and more detailed studies using this test procedure are merited.
    Keywords: STRUCTURAL MECHANICS
    Type: Journal of Testing and Evaluation; 1; July 197
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  • 98
    Publication Date: 2011-08-16
    Description: A general design algorithm based on methods of feasible directions is presented. Zoutendijk's method of feasible directions is first presented as applied to structural design. This method is modified to improve numerical stability of the design process and is then further modified to deal efficiently with infeasible designs. The algorithm requires the analytic gradient of the objective function and the constraint functions which are active at a given stage in the design process. Gradient information is not required for nonactive constraints. Complex constraint functions may be ignored in the initial design stages because violation of these constraints is efficiently overcome later in the design process. The algorithm is demonstrated with elastic design of redundant trusses.
    Keywords: STRUCTURAL MECHANICS
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  • 99
    Publication Date: 2011-08-16
    Description: Analysis of the vibration of the internal structure of a relatively simple flight vehicle structural model consisting of a multicellular box in which two parallel outer face plates (skins) are connected together by several internal plates (ribs) which are parallel to each other and normal to the face plates. Such a box is representative of a wing or stabilizer structure. Three representations of the structure were considered in the computation. The simplest model which can account for the coupling between the face plates and the ribs is a two-dimensional assembly of beams. A more realistic, yet still simple, three-dimensional model has been developed using the Rayleigh-Ritz method. The third computational method employed was the NASTRAN finite-element displacement method. The computational results are compared with experimental data.
    Keywords: STRUCTURAL MECHANICS
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  • 100
    Publication Date: 2011-08-16
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 183; July 1
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