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Unity gain buffer amplifier with a Field Effect Transistor /FET/ differential input stage responds much faster than bipolar transistors when operated at low current levels. The circuit uses a dual FET in a unity gain buffer amplifier having extremely high input impedance, low bias current requirements, and wide bandwidth.
The critical atomic carbon to oxygen ratios, Phi sub C, for incipient soot formation in shock heated acetylene, ethylene, ethane/oxygen/ argon mixtures was measured over the temperature range 2000 K to 2500 K for reactant partial pressures between 0.1 and 0.4 atoms. Absorption of light from a He-Ne laser at 6328A was was used to detect soot. It was observed that the values of Phi sub C for all three fuels increased uniformly with temperature such that at the highest temperatures Phi sub C was considerably greater than unity, i.e. greater than the value of about unity at which solid carbon should have been precipitated on a thermochemical equilibrium basis. Observations were made over periods extending up to about one millisecond, which was well in excess of the time required for the major heat release of the combustion reactions. The relevance of these experimental findings to the problem of soot formation in gas turbine combustion chambers is discussed.
The intensity of turbulence and the Lagrangian correlation coefficient for a liquid rocket combustion chamber were determined experimentally using the tracer gas diffusion method. The results indicate that the turbulent diffusion process can be adequately modeled by the one-dimensional Taylor theory; however, the numerical values show significant disagreement with previously accepted values. The intensity of turbulence is higher by a factor of about two, while the Lagrangian correlation coefficient which was assumed to be unity in the past is much less than unity.
Quantitative discussion of the photochemistry and lifetime against photodecomposition of five interstellar molecules: H2CO, NH3, H2O, CH4, and CO. For the first four molecules, primary photochemical decomposition processes yielding atomic and molecular hydrogen are considered in addition to photoionization. The quantum yield for decomposition of these molecules is unity. For CO, only decomposition to ground-state carbon and oxygen atoms occur, but the quantum yield is not known and may be considerably less than unity. The radiation field in obscuring clouds is estimated, using an interstellar extinction curve for the Perseus region.
Fourteen Ivory Coast tektites exhibit a range of bulk indices of refraction of 1.5156 to 1.5217 plus or minus 0.0004 and of bulk specific gravities of 2.428 to 2.502 plus or minus 0.005. Seven of these Ivory Coast (IVC) tektites were analyzed for major and minor element content. Compared to tektites from other strewn fields, their SiO2 content is low (67.2-69.1%), Al2O3 relatively high (15.8-16.8%), and total iron relatively high but with a more restricted range (6.3-6.8% as FeO). Their lime content is low (0.71-1.35%) compared to Australasian tektites but their MgO/CaO ratio (about 3.1) is unusually high. All other tektite groups have Na2O/K2O ratios less than unity, but the Na2O/K2O ratio of the IVC tektites is slightly greater than unity. Their K/Rb ratios range from 200 to 256 and average 227.
We have determined the accommodation coefficient, gamma, of a helium film from 1.15 to 4 K by measuring the time constant of a rotating superconducting Nb sphere levitated in vapor and covered with a saturated helium film. The conventional assumption of the phenomenological theory of superfluidity, that the order parameter psi vanishes at the free surface of helium II, implies that gamma, is unity and independent of temperature. We find that gamma, is nearly unity above the lambda point, suffers an abrupt drop close to T-lambda, and gradually levels off to the value of about 0.8 at lower temperatures.
The purpose of the present note is to show that on a flat plate where both the wall temperature and mean wall pressure are constant, neither of the limitations of parallel flow or of unity for the turbulent Prandtl number are required in order for the Crocco solution to apply to the turbulent boundary-layer flow. It is shown herein that this result is subject to restrictions on the magnitude of pressure fluctuations. The same analysis is generalized to show that the compressible turbulent boundary layer on an isothermal swept flat plate is independent of the spanwise flow if the molecular Prandtl number is unity.
An investigation of the intensity fluctuations of 28 pulsars near 0.4 GHz indicates that scintillation spectra have a Gaussian shape, scintillation indices are near unity, and the scintillation bandwidth depends linearly on dispersion measure. Observations near 2.5 GHz suggest a strong dependence of the frequency at which scintillation indices fall below unity on dispersion measure. Multistation measurements of scintillation provide values or limits for the scale size of the scattering diffraction pattern. The dependences of scattering parameters on dispersion measure is discussed in terms of the current models. It is suggested that any line of sight through the galaxy encounters increasingly rare, increasingly large deviations of thermal electron density on the scale of 10 to the 11th power cm.
A theoretical investigation was conducted on the open-loop combustion response of monopropellant droplets and sprays to imposed pressure oscillations. The theoretical model was solved as a perturbation analysis through first order, yielding linear response results. Unsteady gas phase effects were considered in some cases, but the bulk of the calculations assumed a quasi-steady gas phase. Calculations were conducted using properties corresponding to hydrazine decomposition. Zero-order results agreed with earlier measurements of hydrazine droplet burning in combustion gases. The droplet response was greatest (exceeding unity in some cases) for large droplets with liquid phase temperature gradients; at frequencies near the characteristic frequency of the liquid phase thermal wave. The response of a spray is less than that of its largest droplet, however, a relatively small percentage of large droplets provides a substantial response (exceeding unity in some cases).
An earlier analysis for the combustion response of a liquid monopropellant strand (hydrazine) was extended to consider individual droplets and sprays. While small drops gave low or negative response, large droplets provided response near unity at low frequencies, with the response declining at frequencies greater than the characteristic liquid phase frequency. Temperature gradients in the liquid phase resulted in response peaks greater than unity. A second response peak was found for large drops which corresponded to gas phase transient effects. Spray response was generally reduced from the response of the largest injected droplet, however, even a small percentage of large droplets can yield appreciable response. An apparatus was designed and fabricated to allow observation of bipropellant fuel spray combustion at elevated pressures. A locally homogeneous model was developed to describe this combustion process which allows for high pressure phenomena associated with the thermodynamic critical point.
The acoustic power transmitted by a variable-area duct section which carries a steady subsonic flow is investigated under the conditions of both upstream- and downstream-propagating incident plane waves. It is found that the ratio of the power transmitted by incident waves moving against the flow to the power transmitted by incident waves moving with the flow is equal to the ratio of the difference between the Mach number and unity to the square of the sum of the Mach number and unity.
It is suggested that the slope of the modulated proton spectrum at low energies (less than 250 MeV) is not well accounted for in a steady state spherically symmetrical cosmic-ray modulation model and therefore may contain information on the effects of latitude variations. Under quasi-steady interplanetary conditions, slopes steeper than unity have been observed for low-energy protons. It is shown that the slope of unity or a steeper slope may be a natural consequence of having a region of enhanced modulation lying immediately above or below the solar equatorial plane and therefore may be due to the variation of interplanetary conditions with heliocentric latitude.
A hydrodynamic description of the density distributions of the ionic products of H2O and CO in the atmosphere of an H2O-dominated comet having 10% CO is given. Two models are discussed. In the first, the effecs of photodissociation, photoionization, and gas-phase reactions are considered. In the second, the effect of an internal ionization source is also included. It is found that while the observed morphology of the H2O(+) coma of Comet Kohoutek (1973f) cannot be explained by gas-phase reactions alone, it is consistent with the presence of a strong internal source of ionization, presumably an electric current flowing through the inner coma. In the latter case the number densities of H2O(+) and CO(+) remain more or less constant within the scale lengths against collisional dissociation by the electron flux of their neutrals. While the abundance ratio of CO(+) to H2O(+) remains considerably less than unity when the internal ionization source is neglected, it is significantly larger than unity when the internal ionization source is included. Consequently, even the so-called 'CO-rich' comets may in reality be H2O-dominated, provided a strong internal source of ionization is operative.
The paper is concerned with errors in temperature retrieval caused by incorrectly assuming that surface emissivity is equal to unity. An error equation that applies to present-day atmospheric temperature sounders is derived, and the bias errors resulting from various emissivity discrepancies are calculated. A model of downward flux is presented and used to determine the effective downward flux. In the 3.7-micron region of the spectrum, emissivities of 0.6 to 0.9 have been observed over land. At a surface temperature of 290 K, if the true emissivity is 0.6 and unit emissivity is assumed, the error would be approximately 11 C. In the 11-micron region, the maximum deviation of the surface emissivity from unity was 0.05.
High-dispersion coude spectrograms of 181 MK standards of types early F through late M, including luminosity classes Ia, Ib, II, and III, are analyzed. It is shown that the brightness ratio of the V and R self-reversed emission peaks (denoted V/R) in the center of the Ca II K line is correlated with spectral type as well as with certain other spectral-type and luminosity-sensitive parameters, including indicators of mass loss and the H-K wing emission lines. The observations indicate that V/R varies smoothly from less than unity in late K and M giants to greater than unity for G giants. This trend appears to be true for bright giants as well but not necessarily for supergiants and seems to hold for the average V/R for a given star, although short-term variations in V/R occur. It is suggested that the V/R values, which can be interpreted in terms of atmospheric motions, may indirectly relate to effects of evolutionary changes in stellar structure and that V/R among late-type stars could be useful as an indicator of both chromospheric activity and the state of stellar evolution.
Measurements have been made of the absolute oxygen atom yields from CO2 photolysis at 1470 and 1302-1306 A; in both cases the yield is unity. The CO generation rates have also been measured in these two wavelength regions, and they are proportional to the oxygen atom generation rates; by implication the CO quantum yields are thus also unity. The CO deficiencies observed in earlier work on this subject are probably caused by heterogenous processes.
The evolution of the two-point correlation function for the large-scale distribution of galaxies in an expanding universe is studied on the assumption that the perturbation densities lie in a Gaussian distribution centered on any given mass scale. The perturbations are evolved according to the Friedmann equation, and the correlation function for the resulting distribution of perturbations at the present epoch is calculated. It is found that: (1) the computed correlation function gives a satisfactory fit to the observed function in cosmological models with a density parameter (Omega) of approximately unity, provided that a certain free parameter is suitably adjusted; (2) the power-law slope in the nonlinear regime reflects the initial fluctuation spectrum, provided that the density profile of individual perturbations declines more rapidly than the -2.4 power of distance; and (3) both positive and negative contributions to the correlation function are predicted for cosmological models with Omega less than unity.
A mathematical model is presented for the transmission of airborne noise through the walls of an orthotropic cylindrical shell. Parameters were varied to see how orthotropicity affected noise transmission. When compared to that for an isotropic shell, the cylinder transmission loss was found to be quite sensitive to the ratio of circumferential to axial modulus of elasticity. A modulus ratio greater than unity appears to enhance transmission loss in the mass-controlled region, while a ratio less than unity degrades it. Below the ring frequency, the trends appear to be reversed. The cylinder transmission loss appears to be relatively insensitive to changes in the shear modulus