On the determination of the effective screw-thread diameter

1959 ◽  
Vol 1 (3) ◽  
pp. 313-313
Author(s):  
B. A. Kaliuta
Keyword(s):  
Screw Thread ◽  
Thread Diameter

scholarly journals A new current weigher, and a determination of the electromotive force of the normal weston cadmium cell

1907 ◽  
Vol 80 (535) ◽  
pp. 12-18
Keyword(s):  
Current Sheet ◽  
Electromotive Force ◽  
Unit Length ◽  
Screw Thread ◽  
Late Professor ◽  
Convenient Formula ◽  
Association Meeting ◽  
Helical Current ◽  
Mutual Induction

The instrument described is the outcome of conversations between the late Professor J. Viriamu Jones, F. R. S., and one of the authors (W. E. A.), on their return from the British Association Meeting held in Toronto in 1897. Its object was to determine “ the ampere ” as defined in the C. G. S. system, to an accuracy comparable with that attained in the absolute determination of the ohm by Lorenz’s apparatus, an account of which was given by Professors Ayrton and Jones at the Toronto Meeting. Professor Jones had previously developed a convenient formula for calculating the electromagnetic force between a helical current and a coaxial current sheet, viz., F = γ h γ (M 2 -M 1 ),† where γ h is the current in the helix, the γ current per unit length of the current sheet, and M 1 , M 2 the coefficients of mutual induction of the helix and the two ends of the current sheet respectively. By using coaxial coils with single layers of wire wound in screw-thread grooves, advantage could be taken of the above formula.

scholarly journals Algorithmic and Computer Software for Determination of Thread Tension After Guide Large Curvacity

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Shcherban ◽  
◽  
Kolva ◽  
Egorov ◽  
Petko ◽  
...  
Keyword(s):  
Input Parameter ◽  
Computer Software ◽  
Radius Of Curvature ◽  
Friction Forces ◽  
Large Curvature ◽  
Thread Diameter ◽  
Formation Zone ◽  
Thread Tension ◽  
Working Bodies

The conducted studies of the effect of the structure of the threads on the amount of tension when interacting with guides and working bodies of weaving machines and knitting machines, which have a large curvature in the zone of contact with the thread, established a mechanism for the process of increasing the tension of the thread after the guide by changing the radius of curvature of the guide and friction forces in the zone contact. It is proved that the increase in tension is explained by a change in the angle of coverage of the thread of a guide of large curvature, and for complex threads and yarns, the real angle of coverage will be greater than the calculated one, due to deformation of the thread diameter in the contact zone, and for monofilaments it is less than the calculated one due to bending stiffness. The sequential passage of the thread along the guides, from the entry zone to the formation zone of fabric and knitwear, leads to a stepwise increase in tension. In this case, the output parameter of the tension after the previous guide will be the input parameter for the subsequent guide, which makes it possible to use recursion when determining the tension in front of the formation zone. In this regard, research on the computer implementation of the algorithm for determining the thread tension on technological equipment using recursion should be considered relevant.

Galactic orbits of stars

1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley
Keyword(s):  
Globular Cluster ◽  
Potential Field ◽  
High Velocity ◽  
Velocity Vector ◽  
Variable Stars ◽  
The Sun ◽  
Proper Motions ◽  
Rr Lyrae ◽  
The Galaxy

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.

Distance to SN 1987A and the LMC

1999 ◽  
Vol 190 ◽  
pp. 549-554
Author(s):  
Nino Panagia
Keyword(s):  
Angular Size ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Light Curves ◽  
Distance Modulus ◽  
Absolute Size ◽  
Sn 1987A

Using the new reductions of the IUE light curves by Sonneborn et al. (1997) and an extensive set of HST images of SN 1987A we have repeated and improved Panagia et al. (1991) analysis to obtain a better determination of the distance to the supernova. In this way we have derived an absolute size of the ringRabs= (6.23 ± 0.08) x 1017cm and an angular sizeR″ = 808 ± 17 mas, which give a distance to the supernovad(SN1987A) = 51.4 ± 1.2 kpc and a distance modulusm–M(SN1987A) = 18.55 ± 0.05. Allowing for a displacement of SN 1987A position relative to the LMC center, the distance to the barycenter of the Large Magellanic Cloud is also estimated to bed(LMC) = 52.0±1.3 kpc, which corresponds to a distance modulus ofm–M(LMC) = 18.58±0.05.

International determination of the total motion of the pole

1961 ◽  
Vol 13 ◽  
pp. 29-41
Author(s):  
Wm. Markowitz
Keyword(s):  
Secular Motion ◽  
The Future

A symposium on the future of the International Latitude Service (I. L. S.) is to be held in Helsinki in July 1960. My report for the symposium consists of two parts. Part I, denoded (Mk I) was published [1] earlier in 1960 under the title “Latitude and Longitude, and the Secular Motion of the Pole”. Part II is the present paper, denoded (Mk II).

Time and Latitude in South Africa

1972 ◽  
Vol 1 ◽  
pp. 27-38
Author(s):  
J. Hers
Keyword(s):  
South Africa ◽  
Cape Town ◽  
Astronomical Observations ◽  
Royal Observatory ◽  
The Republic ◽  
Astronomical Determination ◽  
Limited Accuracy ◽  
Better Than

In South Africa the modern outlook towards time may be said to have started in 1948. Both the two major observatories, The Royal Observatory in Cape Town and the Union Observatory (now known as the Republic Observatory) in Johannesburg had, of course, been involved in the astronomical determination of time almost from their inception, and the Johannesburg Observatory has been responsible for the official time of South Africa since 1908. However the pendulum clocks then in use could not be relied on to provide an accuracy better than about 1/10 second, which was of the same order as that of the astronomical observations. It is doubtful if much use was made of even this limited accuracy outside the two observatories, and although there may – occasionally have been a demand for more accurate time, it was certainly not voiced.

Large-scale Motion of Solar Filaments

2000 ◽  
Vol 179 ◽  
pp. 205-208
Author(s):  
Pavel Ambrož ◽  
Alfred Schroll
Keyword(s):  
Magnetic Flux ◽  
Proper Motion ◽  
Time Scale ◽  
Large Scale ◽  
Accuracy Of Measurements ◽  
Solar Filaments ◽  
General Movement ◽  
Scale Motion ◽  
Velocity Scatter

AbstractPrecise measurements of heliographic position of solar filaments were used for determination of the proper motion of solar filaments on the time-scale of days. The filaments have a tendency to make a shaking or waving of the external structure and to make a general movement of whole filament body, coinciding with the transport of the magnetic flux in the photosphere. The velocity scatter of individual measured points is about one order higher than the accuracy of measurements.

Sign in / Sign up

Export Citation Format

Share Document