A theory of thermospheric dynamics. Part 2 - Geomagnetic activity effect, 27 day variation and semiannual variation
Geomagnetic activity, 27 day variation, and semiannual variation of thermosphere affected by solar activity
Volland, H.↗
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Time dependent variations in sky emission temperatures at millimeter wavelengths. Anomalous sky temperature variation with zenith distance measured at a calm night at a wavelength of 3.2 mm. Measurements of linear polarization of the moon at millimeter wavelengths
Time dependent variations in sky emission temperature, anomalous sky temperature variation with zenith distance on calm nights, lunar linear polarization - millimeter wavelengths
Yamashita, T.↗
Variational equations derived from the Herrick variation of parameters method
Variational equations from Herrick variation of parameters method for Icarus encounter with earth
Liu, A. S.↗
Period variations in pulsating X-ray sources. II - Torque variations and stellar response
A statistical description of variations in the torque acting on a rotating neutron star is developed in terms of stationary random processes and is used to calculate the torque power spectrum, stellar response power spectrum, and the total mean square variation in the crustal angular velocity of the star. The response of a star with a finite frequency internal mode is calculated with the aid of phenomenological equations which correspond to a generalized two-component model of the star. The form of the stellar response functions is examined in a number of limiting cases of physical interest, and the dependence of the response power on both the period of observation and the time over which fluctuating torques have been acting is discussed.
Lamb, F. K.↗
A variational justification of the assumed natural strain formulation of finite elements. I - Variational principles. II - The C(0) four-node plate element
The assumed natural strain formulation of finite elements is interpreted from a variational standpoint. The approach is based on hybrid extensions of the Reissner-type functional which uses the strains and displacements as independent fields. Consideration is restricted to linear elasticity. The four-node C(0) plate-bending quadrilateral is used as a specific example to illustrate the application of the present interpretation. A key finding is that any change in the strain-displacement interpolation from the variationally consistent interpolation must be associated in some way to the addition of incompatible displacement modes.
Militello, Carmelo↗
Variational formulation of high-performance finite elements - Parametrized variational principles
High-performance (HP) elements are simple finite elements constructed to deliver engineering accuracy with coarse arbitrary grids. This paper is part of a series on the variational basis of HP elements, with emphasis on those constructed with the free formulation (FF) and assumed natural strain (ANS) methods. The present paper studies parametrized variational principles that provide a foundation for the FF and ANS methods, as well as for a combustion of both methods.
Felippa, C. A.↗
Variational formulation of high performance finite elements: Parametrized variational principles
High performance elements are simple finite elements constructed to deliver engineering accuracy with coarse arbitrary grids. This is part of a series on the variational basis of high-performance elements, with emphasis on those constructed with the free formulation (FF) and assumed natural strain (ANS) methods. Parametrized variational principles that provide a foundation for the FF and ANS methods, as well as for a combination of both are presented.
Felippa, Carlos A.↗
A comparison between the diurnal variations of the geomagnetic field and the corresponding variations of cosmic-ray intensity
Comparison between diurnal geomagnetic field and cosmic ray intensity variations
DIURNAL VARIATION↗
Effect of changes in solar activity on the coupling coefficients between primary and secondary variations of cosmic rays. some practical problems regarding the determination of the spectrum of the variations
Effect of changes in solar activity on coupling coefficients between primary & secondary cosmic ray variations
COSMIC RADIATION↗
Radioastronomical observations for determining the position of the region of rapid variation of the characteristics of solar variation <opredeleniye polozheniya oblasti bystrogo izmeniya kharaketristik solnechnoy atmosfery po rezul'tatam radioastrono
Radioastronomical determination of solar radio radius by time variations of lunar and solar disk contacts
TIME↗
The variational principle and the variational method 1
Variational method and principle
Epstein, S. T.↗
Prediction of tube wall temperatures with axial variation of heating rate and gas property variation.
Superposition method for predicting tube wall temperatures with gas property and heating rate axial variation, noting application to gas flow problems
Bankston, C. A.↗
Variational energy principle for compressible, baroclinic flow. 1: First and second variations of total kinetic action
The case of a cold gas in the absence of external force fields is considered. Since the only energy involved is kinetic energy, the total kinetic action (i.e., the space-time integral of the kinetic energy density) should serve as the total free-energy functional in this case, and as such should be a local minimum for all possible fluctuations about stable flow. This conjecture is tested by calculating explicit, manifestly covariant expressions for the first and second variations of the total kinetic action in the context of Lagrangian kinematics. The general question of the correlation between physical stability and the convexity of any action integral that can be interpreted as the total free-energy functional of the flow is discussed and illustrated for the cases of rectillinear and rotating shearing flows.
Schmid, L. A.↗
Possible origins of time variability in Jupiter's outer magnetosphere. I - Variations in solar wind dynamic pressure. II - Variations in solar wind magnetic field
Attention is given to the effect of changes in the dynamic pressure of the solar wind on the structure of a centrifugally driven planetary wind from Jupiter. It is suggested that dynamic pressure variations can induce a transition between a super-Alfvenic wind and a sub-Alfvenic wind breeze on Jupiter's dayside. This could possibly account for the observed large-scale changes in the structure of Jupiter's outer magnetosphere. An attempt is then made to conceptually merge planetary wind models of Jupiter's outer magnetosphere with reconnection models of Jupiter's outer magnetosphere.
Coroniti, F. V.↗
Variations including possible solar cycle variations of stratospheric ozone over central Switzerland
The annual variation of the total amount of ozone over central Switzerland and the partial pressures in each of 7 layers from the surface to 7.8 m zeta shows the pattern representative of mid-latitude ozone: summer maximum in the troposphere, spring maximum in the lower stratosphere up to 30 mb and summer maximum in the middle stratosphere up to approx. mb. It was also shown that at the level of the ozone maximum the ozone partial pressure has a pronounced period of about 26 months. Total ozone and the ozone concentration in the different layers have marginally significant (at plus or minus sigma) correlations with relative sunspot number. The time lag for these correlations is long in the troposphere (about 36 months) but decreases with height to the level of ozone maximum (to about 2 months). A similar analysis of the data derived from the ozonesonde program at Hohenpeissenberg, Germany (GFR) gave completely consistent results with those discussed above.
London, J.↗
Short-term cyclic variations and diurnal variations of the Venus upper atmosphere
The vertical structure of the nighttime thermosphere and exosphere of Venus was discussed. A comparison of the day and nighttime profiles indicates, contrary to the model of Dickinson and Riley (1977), that densities (principally atomic oxygen) dropped sharply from day to night. It was suggested either that the lower estimates were related to cooler exospheric temperatures at night or that the atomic bulge was flatter than expected at lower altitudes. Large periodic oscillations, in both density and inferred exospheric temperatures, were detected with periods of 5 to 6 days. The possibility that cyclic variations in the thermosphere and stratosphere were caused by planetary-scale waves, propagated upward from the lower atmosphere, was investigated using simultaneous temperature measurements obtained by the Venus radiometric temperature experiment (VORTEX). Inferred exospheric temperatures in the morning were found to be lower than in the evening as if the atmosphere rotated in the direction of the planet's rotation, similar to that of earth. Superrotation of the thermosphere and exosphere was discussed as a possible extension of the 4-day cyclic atmospheric rotation near the cloud tops.
Keating, G. M.↗