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Gas phase reaction between ions and molecules using mass spectrometry with time as kinetic variable, specifically methane-deuterium mixtures
Twenty-six galaxies from the Infrared Astronomy Satellite (IRAS) point source catalog were observed at 250 and 1300 microns. The Far Infrared (FIR) spectra from 25 to 1300 microns are interpreted in terms of two dust components of about 16 and 53 K. Flux densities at 1300 microns are used to estimate the total gas mass M sub g. The warm dust luminosity L sup W is considered to be proportional to M sub g sup 0.9 in the mass range 3 x 10 to the 8th is equal to or less than M sub g/solar mass is equal to or less than 10 to the 12th power. The efficiency of star formation seems to be four times higher in barred and peculiar galaxies than in Sc types.
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A list of the 21 mass-losing red supergiants (20 M type, one G type; L greater than 100,000 solar luminosities) within 2.5 kpc of the sun is compiled. These supergiants are highly evolved descendants of main-sequence stars with initial masses larger than 20 solar masses. The surface density is between about 1 and 2/sq kpc. As found previously, these stars are much less concentrated toward the Galactic center than W-R stars, which are also highly evolved massive stars. Although with considerable uncertainty, it is estimated that the mass return by the M supergiants is somewhere between 0.00001 and 0.00003 solar mass/sq kpc yr. In the hemisphere facing the Galactic center there is much less mass loss from M supergiants than from W-R stars, but, in the anticenter direction, the M supergiants return more mass than do the W-R stars. The duration of the M supergiant phase appears to be between 200,000 and 400,000 yr. During this phase, a star of initially at least 20 solar masses returns perhaps 3-10 solar masses into the interstellar medium.
Coaxial hall-current plasma accelerator with low mass flow rate
Tandem column gas-liquid chromatography labeling technique for mass spectrometry, noting ketones exchange and data on deutrium and oxygen compounds
Chronic acceleration and acute Co 60 whole body irradiation effects on rats, discussing weight to mass ratio
Asteroidal and cometary orbits and origin of meteorites, discussing eccentricities, exposure ages and mass yield
Least squares integral criterion for representation of gravitational potential with fixed mass points
The problem of modal analysis of an elastic appendage on a rotating base is examined to establish the relative advantages of various mathematical models of elastic structures and to extract general inferences concerning the magnitude and character of the influence of spin on the natural frequencies and mode shapes of rotating structures. In realization of the first objective, it is concluded that except for a small class of very special cases the elastic continuum model is devoid of useful results, while for constant nominal spin rate the distributed-mass finite-element model is quite generally tractable, since in the latter case the governing equations are always linear, constant-coefficient, ordinary differential equations. Although with both of these alternatives the details of the formulation generally obscure the essence of the problem and permit very little engineering insight to be gained without extensive computation, this difficulty is not encountered when dealing with simple concentrated mass models.
An analytical and experimental research program was performed to investigate the effects of flexible tanks and lines and the total system dynamic response of a simple physical system which had some of the essential features of a liquid-fueled launch vehicle. Several vessel-wall materials were used to obtain a range of elastic moduli. Water was used to simulate the fuel and an electromagnetic shaker provided external excitation such as might originate from a rocket-propulsion system. Experimental data were compared to values obtained from mathematical models for the many degree-of-freedom lumped-mass representation.
The hypothesis that pulsating X-ray sources could be vibrating white dwarfs is investigated. The masses are calculated for several white-dwarf models having various modes of vibration which have the observed eigenfrequencies of the Centaurus X-3 and the Hercules X-1 sources. If the hypothesis is correct, Cen X-3 is vibrating radially in the fundamental mode or not higher than the first two overtones, and its mass is in the range 0.7-1.2 solar masses. The Her X-1 source would be vibrating in a quadrupole P mode, and would have a mass in the range 1.1-1.25 solar masses.
Five MHz radar data obtained from the Apollo 17 mission are used to determine elevation profiles of the moon. A change in range of one quarter of a wavelength (15 m for the 5 MHz radar) changes the round-trip radar range one half wavelength or 180 deg, thus allowing determination of the relative surface profile or slope with a high degree of precision. The technique of deriving the range or altimetry measurement from the range-Doppler data record on film yields a better understanding of the range accuracy. The presence of fade intervals can be observed directly and their effect on the profile measurement reduced to a minimum. The maria used to generate the center of maria are Western Procellarum, Serenitatis, and Crisium. The location of the center of mare relative to the center of figure and center of mass is identified.
A numerical study to determine the temperature distribution in the guide vanes of a radial inflow turbine is presented. A computer program has been developed to calculate the temperature distribution when the vanes are cooled internally using a combination of impingement and film cooling techniques. The study is based on the use of the finite difference method in a two dimensional heat conduction problem. The results are then compared to determine the best cooling configuration for a certain coolant to primary mass flow ratio.
Measurements of the downward solar radiant flux in the St. Louis area are compared with predictions from an approximate solution to the radiative transfer equation. The atmospheric aerosols were assumed to have a power size distribution and the refractive indices suggested by Fischer (1973) for an urban area. On a relatively clean day, the predictions compared well with observations. On a hazy day, the comparison was poor with the a priori choice of aerosol properties. The particles on the hazy day apparently had more submicron particles than those found in the assumed size distribution, and the particles were considerably less absorbing than those observed by Fischer. These changes could represent the effects of relative humidity and different air mass characteristics.
The described NASA program is to provide the technology base to meet the U.S. future needs in the area of low thrust, high specific impulse propulsion. An electric propulsion system will be needed to augment the Shuttle-IUS Space Transportation System for space missions involving the exploration of the solar system. Plans exist in this connection for comet and asteroid rendezvous, a Saturn and a Mercury orbiter, and a Mars surface sample return. An analysis has shown that electric propulsion can be used to obtain larger payloads, shorter trip times, more mission flexibility, and less complicated trajectories. In addition, electric propulsion has also potential uses for earth orbital missions. Attention is given to the auxiliary propulsion technology program which is to develop a one millipound electron bombardment thrust system, a baseline program concerned with a 3 kilowatt thrust system, ion thruster research, magnetoplasmadynamic thruster research and evaluation, and the use of a mass driver as a reaction mass propulsion system.
The unique set of operating constraints determining key concentrating solar array design characteristics for low earth orbital, geosynchronous and interplanetary missions are considered. Minimum cost is crucial at low earth orbits, performance and design life are needed in geosynchronous orbit, and structural pointing accuracy and radiation resistance are essential in interplanetary designs. The impact of such emerging technologies as ultrathin cells, gallium arsenide cells and cold mirrors is discussed. Power-to-mass ratios as high as 200 W per kilogram at a distance of 1 astronomical unit from the sun are possible, using concentrators in conjunction with gallium arsenide arrays.
A design and ground test program was conducted to study the performance of the monofilar absorber for vibration reduction on a four-bladed helicopter. A monofilar is a centrifugal tuned two degree-of-freedom rotor hub absorber that provides force attenuation at two frequencies using the same dynamic mass. Linear and non-linear analyses of the coupled monofilar/airframe system were developed to study tuning and attenuation characteristics. Based on the analysis, a design was fabricated and impact bench tests verified the calculated non-rotating natural frequencies and mode shapes. Performance characteristics were measured using a rotating absorber test facility. These tests showed significant attenuation of fixed-system 4P hub motions due to 3P inplane rotating-system hub forces. In addition, detuning effects of the 3P monofilar modal response were small due to the nonlinearities and tuning pin slippage. However, attenuation of 4P hub motions due to 5P inplane hub forces was poor. The performance of the 5P monofilar modal response was degraded by torsional motion of the dynamic mass relative to the support arm which resulted in binding of the dynamic components. Analytical design studies were performed to evaluate this torsional motion problem. An alternative design is proposed which may alleviate the torsional motion of the dynamic mass.