Inertia Change Research Articles

Physiology of peripheral neurons innervating semicircular canals of the squirrel monkey. 3. Variations among units in their discharge properties.

WERSXLL (17) was the first to describe the two kinds of hair cells found in the sensory epi thelium and to demonstrate that they had different nerve supplies. The type I hair cell, peculiar to birds and mammals, is a relatively large, flask-shaped cell and is innervated by a calycoid ending derived from a single, usually thick, afferent fiber. The type II hair cell, common throughout the vertebrate scale, is thin and cylindrically shaped. It receives bud-shaped endings from several afferents. Wersall’s observations were foreshadowed in the classical silver studies of Cajal (2, 3) and of Lorente de No (10) and have been amply confirmed in more recent ultrastructural (1, 4, 9, 11, 15, 18) and light microscopic studies (1, 9). These morphological complexi ties should be reflected in the physiology of mammalian vestibular afferents. On the basis of the two preceding papers (6, s>, it may be concluded that neurons innervating the semicircular canals of mammals do vary from one another in their discharge characteristics. Neurons differ in the regularity of spacing of their action potentials, in the level of their resting activity, in their sensitivity to angular accelerations, and in their dynamic properties. Were these differences a reflection of differences in the i nnerva tion patterns of the parent sensory axons, it might be ex-

Physiology of peripheral neurons innervating semicircular canals of the squirrel monkey. II. Response to sinusoidal stimulation and dynamics of peripheral vestibular system.

A CENTRAL PROBLEM in vestibular physiology has been the elucidation of the dynamics of the peripheral vestibular apparatus. Following the development of the torsion-pendulum model by Steinhausen (24, 25), many efforts have been directed toward the determination of the time constants of the model. That the model, itself, might not adequately describe the transfer characteristics of the peripheral system has seldom been questioned. Further, the procedures employed to estimate the time constants have had their drawbacks. The dynamics of the system have sometimes been deduced from hydrodynamic principles (5, 6, 15, 17, 22, 23). Such an analysis permits the inference of only some of the relevant variables. In the torsionpendulum model, it will be recalled, the angular deflection of the cupula g(t) is related to the angular acceleration a(t) by the equation

The "feel" of rotary controls: friction and inertia.

The purpose of this study was to determine the influence of friction and inertia levels on the “feel” of rotary controls. Detection thresholds for changes in friction and inertia were determined and found to be about 10 to 20 per cent of the initial values. Preference ratings obtained for various combinations of friction and inertia increased as a function of inertia level and decreased as a function of friction level. Preferences for viscous friction were greater than for stick-slip friction. Psychophysical evaluations such as these are related to customer acceptance factors and provide a useful supplement to purely functional design criteria.

Dynamic Response of an Asymmetrical Spinning Space Station

The dynamic equations for a rigid asymmetrical spinning space station with an internal movable mass are presented in the appendix. The body rates induced by certain mass movements are shown to be elliptic functions for the uncontrolled space station. This assumes the mass movement is simulated by impulsive product of inertia changes. A linear analysis is presented for the controlled space station using a gyroscopic controller. The controller provides nutation damping and limited precession control.

The controlled retardation of Ward Leonard drives

The behaviour of minimum-time-response second-order control system is widely known, and in the paper the philosophy of this type of response is extended to the problem of the control of a third-order drive responding to a step in output displacement.The minimum time response of a system is related to physical limitations of the system in respect of speed, torque (i.e. acceleration), and rate of change of torque. These limitations define the characteristics of the optimum traverse cycles, and relationships are derived that may be used to design a controller for operating a drive in accordance with these cycles. These principles have been used to construct a model incorporating a 3 kW Ward Leonard drive. Satisfactory performance is demonstrated with positive and negative load torques and with a substantial change in load inertia.

Search for the Anisotropy of Inertia Using the Mössbauer Effect inFe57

The width of the central resonance absorption line in the Mossbauer effect in Fe/sup 57/ being wider than the natural linewidth suggests that an external perturbation exists which affects the nuclear levels. Accordingly, experiments were carried out to detect whether anisotropy in inertia (due to nonuniform distribution of matter in the galaxy) may be responsible for the line broadening. The linewidth was measured for a Fe/sup 57/ source and a Fe absorber with (1) no magnetic field present and (2) both source and absorber parallel to magnetic fields of about 10/sup 3/ gauss; no difference was found. Next, the amplitudes of the center of the line and of four Doppler-shifted points on the side of the line were measured with 600-gauss magnetic fields oriented at +45 deg and --45 deg in the vertical (north-south) plane at different times so that the galactic center exerts its maximum and minimum effects on the level shift, The amplitudes were found to be constant within the statistical limits, which give a result of DELTA M/M (fraction of inertia change) of (5 x 10/sup -16/ (D.L.C.)

The Beta Bands of Nitric Oxide. II. Intensity Relations and Their Interpretation

Relative intensities of band lines.---The equations of H\"onl and London predicting the relative intensities of band spectrum lines have been tested with the NO $\ensuremath{\beta}$ bands ($^{2}P\ensuremath{\rightarrow}^{2}P$ transition), a system emitted by an odd molecule, in the same way that they were recently teste d by one of the writers with certain spectra of even molecules. Plates of the $\ensuremath{\beta}$ bands used n connection with Part I were measured with a densitometer. The data are compared with theory, first, as to order of intensity of lines, and, second, as to quantitative intensities calculated from densities under reasonable assumptions. (Calibration curves of the relationship between light intensity and photographic density for the plates were unfortunately not available.) Best agreement is obtained if it is assumed that the effective temeperature of the active nitrogen source was about 47\ifmmode^\circ\else\textdegree\fi{}C. The observed relative line intnsities are then in essential agreement with those predicted by the H\"onl and London equation s. Possible slight departures from exact agreement are discussed. The two sub-bands ($^{2}P_{1}\ensuremath{\rightarrow}^{2}P_{1}$ and $^{2}P_{2}\ensuremath{\rightarrow}^{2}P_{2}$) in each band are found to be approximately equal in intensity, in agreement with Hund's theory.Missing lines and $Q$ branches.---The densitometer curves confirm the conclusions of Part I as to the actual absence of lines expected to be missing if the electronic transitions are $^{2}P_{1}\ensuremath{\rightarrow}^{2}P_{1}$ and $^{2}P_{2}\ensuremath{\rightarrow}^{2}P_{2}$. The shape of the quantitative intensity curves as a function of $j$ is given correctly by the equations of H\"onl and London, for low values of $j$, only if the values ${{\ensuremath{\sigma}}_{1}}^{\ensuremath{'}}={{\ensuremath{\sigma}}_{1}}^{\ensuremath{'}\ensuremath{'}}=\frac{1}{2}$ for $^{2}P_{1}$ and ${{\ensuremath{\sigma}}_{2}}^{\ensuremath{'}}={{\ensuremath{\sigma}}_{2}}^{\ensuremath{'}\ensuremath{'}}=1\frac{1}{2}$ for $^{2}P_{2}$ are used in the equations. The values of $\ensuremath{\sigma}$ are thereby directly determined to within about a quarter unit.Band intensities.---Curves for the potential energy of the NO molecule as a function of nuclear separation have been calculated from the data of Part I. These have been used by Condon's method to predict the relative intensities of the bands of the $\ensuremath{\beta}$ system. These are compared with the relative intensities observed recently by R. C. Johnson and H. G. Jenkins. The principal features of the intensity distribution, which is that typical of a molecule whose moment of inertia changes considerably during emission, are as predicted, but certain discrepancies are noted.