IX.—On the Toothing of Un-round Discs which are intended to Roll upon each other

1877 ◽  
Vol 28 (1) ◽  
pp. 191-195
Author(s):  
Edward Sang
Keyword(s):  
General Problem ◽  
The Sun ◽  
Turn On ◽  
Angular Velocities

The construction of the toothed wheels used in machinery gives rise to some very interesting investigations in the geometry of motion. The general problem is so to shape the contours as that they shall remain in contact while the wheels turn on their centres with uniform angular velocities.The inquiry becomes more extensive when the velocities of the wheels are to be variable; as, for example, when we seek to imitate the revolutions of the planets round the sun, and for that purpose introduce the equation of the centre.In these cases the wheels are supposed to turn on fixed centres; but we may still farther extend the scope of our researches by removing the centres and subjecting the discs to the single condition that they roll upon each other.If two discs A and B touch at the point S, and if they so move as that the point of contact shifts equally along the two boundaries, they are said to roll on each other; that is to say, if we measure equal distances ST, SV along the two boundaries, the points T and V will come together in the course of the movements.

scholarly journals Cross-field Current Closure Below the Solar Photosphere

1994 ◽  
Vol 47 (3) ◽  
pp. 361 ◽  
Author(s):  
MS Wheatland ◽  
DB Melrose
Keyword(s):  
Simple Model ◽  
Current Density ◽  
Characteristic Length ◽  
Solar Photosphere ◽  
The Sun ◽  
Diffusive Process ◽  
Turn On ◽  
First Case

A simple model is developed to describe how an externally imposed current closes as a function of time below the photosphere. A vertical current density is assumed to turn on at the photospheric boundary. The model implies that the subsequent closure of the current in the sub-photosphere depends only on the ratio RA/ R, where RA = /-LaVA is the Alfvenic impedance of the photosphere and = I/o-pI is the resistance corresponding to the conductivity O-p and a characteristic length 1. For RA/R � 1, current closure occurs at a front, propagating with the Alfven speed. For RA/ R 1, current closure is a diffusive process ahead and behind a slowly propagating Alfvenic front. The first case is the relevant one for the Sun, where RA/ R /VA, for VA in kilometres per second.

scholarly journals ON THE VARIABILITY OF CRITICAL ILLUMINATION FOR FLICKER FUSION AND INTENSITY DISCRIMINATION

1936 ◽  
Vol 19 (3) ◽  
pp. 503-522 ◽  
Author(s):  
W. J. Crozier
Keyword(s):  
Visual Acuity ◽  
General Problem ◽  
Visual Function ◽  
Visual Discrimination ◽  
Dark Adaptation ◽  
Intensity Discrimination ◽  
The Sun ◽  
Threshold Response ◽  
Independent Variable ◽  
Flicker Fusion

From the data of experiments with bees in which threshold response is employed as a means of recognizing visual discrimination between stripes of equal width alternately illuminated by intensities I1 and I2, it is shown that the detectable increment of intensity ΔI, where ΔI = I2 - I1, is directly proportional to σI2 (I1 being fixed). From tests of visual acuity, where I1 = 0 and the width of the stripes is varied, σI2 = kI2 + const.; here I2 = ΔI, and ΔI/I2 = 1. When the visual excitability of the bee is changed by dark adaptation, λI ≡ kΔI (= k' σΔI) = k'' I + const. For the measurements of critical illumination at threshold response to flicker, σI2 (= σΔI) = k I2 = k' ΔI + const. The data for critical illumination producing threshold response to flicker in the sun-fish Lepomis show for the rods σI2 = K I2 for the cones σI2 = K'(I2 + const.). The data thus indicate that in all these experiments essentially the same visual function is being examined, and that the recognition of the production of a difference in effect by alternately illuminated stripes takes place in such a way that d (ΔI)/d (σI2) = const., and that ΔI is directly proportional to I (or "I2," depending on the nature of the experiment). It is pointed out that the curve for each of the cases considered can be gotten equally well if mean I or σI is plotted as a function of the independent variable involved in the experiment. Certain consequences of these and related facts are important for the treatment of the general problem of intensity discrimination.

scholarly journals Everything Is A Circle: A New Universal Orbital Model

2021 ◽  
Author(s):  
AslıPınar Tan
Keyword(s):  
Solar System ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Ecliptic Plane ◽  
The Sun ◽  
The Moon ◽  
Circular Orbits ◽  
Orbital Parameters ◽  
The Earth ◽  
Angular Velocities

Based on measured astronomical position data of heavenly objects in the Solar System and other planetary systems, all bodies in space seem to move in some kind of elliptical motion with respect to each other. According to Kepler’s 1st Law, “orbit of a planet with respect to the Sun is an ellipse, with the Sun at one of the two foci.” Orbit of the Moon with respect to Earth is also distinctly elliptical, but this ellipse has a varying eccentricity as the Moon comes closer to and goes farther away from the Earth in a harmonic style along a full cycle of this ellipse. In this paper, our research results are summarized, where it is first mathematically shown that the “distance between points around any two different circles in three dimensional space” is equivalent to the “distance of points around a vector ellipse to another fixed or moving point, as in two dimensional space”. What is done is equivalent to showing that bodies moving on two different circular orbits in space vector wise behave as if moving on an elliptical path with respect to each other, and virtually seeing each other as positioned at an instantaneously stationary point in space on their relative ecliptic plane, whether they are moving with the same angular velocity, or different but fixed angular velocities, or even with different and changing angular velocities with respect to their own centers of revolution. This mathematical revelation has the potential to lead to far reaching discoveries in physics, enabling more insight into forces of nature, with a formulation of a new fundamental model regarding the motions of bodies in the Universe, including the Sun, Planets, and Satellites in the Solar System and elsewhere, as well as at particle and subatomic level. Based on the demonstrated mathematical analysis, as they exhibit almost fixed elliptic orbits relative to one another over time, the assertion is made that the Sun, the Earth, and the Moon must each be revolving in their individual circular orbits of revolution in space. With this expectation, individual orbital parameters of the Sun, the Earth, and the Moon are calculated based on observed Earth to Sun and Earth to Moon distance data, also using analytical methods developed as part of this research to an approximation. This calculation and analysis process have revealed additional results aligned with observation, and this also supports our assertion that the Sun, the Earth, and the Moon must actually be revolving in individual circular orbits.

scholarly journals The Differential Rotation and Evolution of Spots on UX Arietis from a Sequence of Doppler Images

1991 ◽  
Vol 130 ◽  
pp. 297-308
Author(s):  
Steven S. Vogt ◽  
Artie P. Hatzes
Keyword(s):  
Angular Velocity ◽  
Velocity Distribution ◽  
Differential Rotation ◽  
The Sun ◽  
High Latitudes ◽  
Time Intervals ◽  
A Value ◽  
Angular Velocities ◽  
The Difference

AbstractWe present a sequence of three Doppler images of the spotted RS CVn star UX Arietis obtained over a 5-month interval from August 1986 through January 1987. The spot distribution was quite complex and consisted of a large stable polar spot, a spot near the equator, and several other spots at intermediate positive and negative latitudes. The time intervals between successive images were small enough that we were able to reliably track the evolution of the spot distribution, measuring accurate longitudes, latitudes, and areas of the major spots, as well as their drift rates in longitude and latitude. The longitudinal drifts of spot features at equatorial, intermediate, and high latitudes yielded an accurate measurement of differential rotation. We find that the spotted primary of UX Arietis is indeed rotating differentially and in the sense opposite to that of the Sun, i.e. the poles rotate faster than the equator. The equator is synchronized to the orbital angular velocity, and the angular velocity increases towards either pole. The angular velocity distribution can be expressed as Ω(°/day) = −55.91 + 1.09(±0.09) sin2∅, where ∅ is the latitude. The amount of differential rotation, parameterized as the ratio of the difference between the equatorial and polar angular velocities to the equatorial angular velocity, is then α = −0.020(±0.002), as compared to a value of α = +0.2 for the Sun.

scholarly journals SISTEM PENGATUR GORDEN PADA LAMPU BERBASIS PLC

2020 ◽  
Vol 1 (1) ◽  
pp. 20-26
Author(s):  
Hartono Budi Santoso ◽  
Agoeng H Rahardjo ◽  
Risa Utami Arsaf
Keyword(s):  
The Other ◽  
The Sun ◽  
Push Button ◽  
Turn On ◽  
Limit Switch

When we leaving house in the empty situation which usually let the lamp on make wasting the energy we used and invited wickedness like robbing. Based on this situation the author create some device which give a savety when leaving house. Function of this device are to control curtain and lamp automatically. So we can spit people that house not empty. The principle of this device is if user turn on the system with press the push button then at the sun rise curtain automatally open until the lamp will off, and the other way curtain will automatically close and lamp will be on at the sunset. The system consists of two subsystem: motor and railway curtain track. The whole system is controlled by PLC type OMRON CPM 1A. LDR is a sensor to detect the light which places in out site room. Limit switch placed at the end of railway curtain track which used to stop the motor. After testing, we know that the system need 3 minutes for open the curtain and 5 minutes 20 second for close the curtain.

UTILIZATION OF BOOSTER CIRCUIT JOULE THIEF FOR GARDEN LIGHTING SOURCE OF VOLTAGE FROM THE SUN

JURTEKSI ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 103-110
Author(s):  
Ricki Ananda ◽  
Muhammad Amin
Keyword(s):  
Control System ◽  
Research Method ◽  
Quantitative Method ◽  
The Sun ◽  
Solar Panels ◽  
Solar Module ◽  
Led Light ◽  
Turn On ◽  
Module Systems

Abstract: Garden lighting from a sun source utilizes a series of joule thieves so that the lighting of the garden lights at night is bright. This research method uses a quantitative method because it must be tested on each module so that it finds that there are three types of module systems to be combined, the booster or joule electronic thief module, the supply media solar module circuit, and finally, the control system with the Arduino nano board. The solar module used is a 1-watt solar module with 1n4004 diodes, which will convert the heat of sunlight into voltage. The voltage will be sent via the IC TP4056 input, the output from the IC TP4056 will charge the 18650 battery, which aims to ignite the booster circuit on the 12 W lamp, or the 3.7VDC input from the 18650 battery capable of turning on the 12W/220VAC led light. While the controller is connected to the LDR sensor and relay when the user makes the command, LDR > 800 of the provisions, the relay position from NC becomes open, or during the day, the relay will be in the NC position and turn off the 12W light in the booster circuit, while at night the relay will remain in the no position, so that it will connect the booster circuit voltage and turn on the 12W lamp (LDR < 800).Keywords: booster circuit; campus park lighting; solar panels  Abstrak: Penerangan taman dari sumber matahari memanfaatkan rangkaian joule thief agar penerangan lampu taman pada malam hari terang. Metode penelitian ini menggunakan metode kuantitatif dikarenakan harus diuji coba pada tiap modul, sehingga mendapati ada tiga jenis sistem modul yang akan digabungkan, modul elektronika rangkaian booster atau joule thief, rangkaian modul surya media pensuplly, dan terakhir sistem controller dengan board arduino nano. Modul surya yang digunakan modul surya 1 watt dengan dioda 1n4004, akan mengubah panas cahaya matahari menjadi tegangan . Tegangan akan dikirimkan melalui input IC TP4056, output dari IC TP4056 akan mengisi baterai 18650 yang bertujuan sebagai penyala rangkaian booster pada lampu 12 W, atau input 3.7VDC dari baterai 18650 mampu menyalakan lampu led 12W/220VAC. Sementara controller terhubung kesensor ldr dan relay, ketika perintah yang dibuat oleh user, ldr > 800 dari ketentuan, posisi relay dari nc menjadi open, atau siang hari, relay akan diposisi nc dan mematikan lampu 12W pada rangkaian booster, sementara jika malam hari relay akan diposisi no, sehingga akan menghubungkan tegangan rangkaian booster dan menyalakan lampu 12W (ldr < 800).  Kata kunci : panel surya, penerangan taman, rangkaian booster. 

scholarly journals On the Distribution of Angular Velocity in the Sun

1976 ◽  
Vol 71 ◽  
pp. 415-415
Author(s):  
Jaakko Tuominen
Keyword(s):  
Angular Velocity ◽  
Differential Rotation ◽  
Rotational Velocity ◽  
The Sun ◽  
Large Area ◽  
Heliographic Latitude ◽  
Left Hand ◽  
Right Hand ◽  
Angular Velocities ◽  
The Right

The angular velocity distribution as a function of heliographic latitude is directly observed at the solar surface. Also the dependence of the angular velocity on the distance from the solar centre can be studied observationally for the outermost layers of the Sun. But within the Sun the study of angular velocity depends very much on assumptions. One possibility to study the problem is given by the fact that in a bipolar magnetic group the leader is compact while the follower is dispersed over a large area. In Leighton's theory, following Babcock, this phenomenon is explained, in principle, in the following way: Slide 1. When a magnetic rope, as a result of magnetic buoyancy, rises to the surface, it is twisted by differential rotation. Dashed lines in the figure represent isotachial surfaces. When the rope has risen to the surface, the two ends are twisted in opposite directions. The surface differential rotation continues to twist one of the now free ends of the rope, while it untwists the other free end. Both twisting and untwisting are, in fact, very slow. They are fastest at the latitude of 35°, where the magnetic rope is rotated once in 26 days. We understand that the distribution of angular velocity within the Sun is involved in this picture. The twisting in the interior can be written equal to the untwisting of the follower spot produced by the surface differential rotation. Of course there are many solutions. Slide 2 gives two of them. The lines represent calculated isotachial surfaces and the numbers give the observed angular velocities in radians per day. In the left-hand side distribution the velocity decreases inwards, while in the right-hand side distribution it increases inwards. The right-hand side distribution is also consistent with the conclusion derived from observations that the tilt of sunspot axes from the vertical is relatively small, and with the observation that at the equatorial plane, near the surface, the rotational velocity does not vary with depth.

scholarly journals Spectroscopic Observations of Differential Rotation With Height in the Solar Envelope

1970 ◽  
Vol 4 ◽  
pp. 321-328
Author(s):  
W.C. Livingston
Keyword(s):  
Angular Velocity ◽  
Differential Rotation ◽  
Velocity Gradient ◽  
Surface Currents ◽  
The Sun ◽  
Rotational Component ◽  
Spectroscopic Observations ◽  
Angular Velocities

AbstractThe problem of determining the spectroscopic rotation of the sun is not one of instrumental sensitivity, which can be about 10 m/sec, but rather of abstracting the rotational component from the hierarchy of long-lived surface currents. Required are continued daily observations over long periods of time and this task is not presently feasible at most observatories. Past observations have indicated a height gradient of rotational angular velocities. We have determined the photosphere and chromosphere angular velocity gradient from observations across the disk of C 5380 Å(h≃ -250 km), CN 3882 Â (h ≃ 0 km), Ca+K3(h≃+ 5000 km), together with other Fraunhofer lines of intermediate origin while K-line spectra of prominences are used to sense the chromosphere-corona interface.

scholarly journals Safety-Aware Optimal Attitude Pointing for Low-Thrust Satellites

2021 ◽  
Vol 11 (7) ◽  
pp. 3002
Author(s):  
Helen Henninger ◽  
James Biggs ◽  
Karl von Ellenrieder
Keyword(s):  
Reinforcement Learning ◽  
Group Representation ◽  
Learning Algorithm ◽  
The Sun ◽  
Low Thrust ◽  
Geosynchronous Satellite ◽  
The Earth ◽  
Attitude Maneuver ◽  
Angular Velocities ◽  
Free Parameters

In geostationary orbit, long eclipses and the seasonal variations in the direction and intensity of the solar input can cause damage to sensitive equipment during attitude maneuvers, which may inadvertently point the equipment towards the Sun. The requirement that transmitting and receiving antennae remain pointed towards the Earth creates further restrictions to pointing directions. The aim of the study is to construct a novel geometric and reinforcement-learning-based method to determine attitude guidance maneuvers that maintain the equipment in safe and operational orientations throughout an attitude maneuver. The attitude trajectory is computed numerically using the geometric framing of Pontryagin’s maximum principle applied to the vehicle kinematics using the global matrix Lie group representation on SO(3), and the angular velocities are shaped using free parameters. The values of these free parameters are determined by a reinforcement learning algorithm to avoid the forbidden areas while maintaining the pointing in operational areas (modeled as subsets of the two-sphere of all possible pointing directions of a particular axis). The method is applied to a model geosynchronous satellite and demonstrated in a simulation.

Chromospheric activity as a function of age in main-sequence stars

1966 ◽  
Vol 24 ◽  
pp. 40-43
Author(s):  
O. C. Wilson ◽  
A. Skumanich
Keyword(s):  
Main Sequence ◽  
The Sun ◽  
Main Sequence Stars ◽  
Tentative Conclusion ◽  
Chromospheric Activity ◽  
General Field ◽  
Large Clusters

Evidence previously presented by one of the authors (1) suggests strongly that chromospheric activity decreases with age in main sequence stars. This tentative conclusion rests principally upon a comparison of the members of large clusters (Hyades, Praesepe, Pleiades) with non-cluster objects in the general field, including the Sun. It is at least conceivable, however, that cluster and non-cluster stars might differ in some fundamental fashion which could influence the degree of chromospheric activity, and that the observed differences in chromospheric activity would then be attributable to the circumstances of stellar origin rather than to age.

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