The Design and Simulation of an Astronomical Clock

This paper describes and explains the synthesis of an astronomical clock mechanism which displays the mean position of the Sun, the Moon, the lunar node and zodiac circle as well as the Moon phases and their motion during the year as seen from the Earth. The clock face represents the stereographic projection of the celestial equator, celestial tropics, zodiac circle (ecliptic) and horizon for the latitude of Belgrade from the north celestial pole to the equator plane. The observed motions of celestial objects are realized by a set of clock gear trains with properly calculated gear ratios. The method of continued fraction is applied in the computation of proper and practically applicable gear ratios of the clock gear trains. The fully operational 3D model of the astronomical clock is created and the motion study of its operation is accomplished by using the SolidWorks 2016 application. The simulation results are compared with the ephemeris data and the detected differences are used to evaluate the long-term accuracy of the astronomical clock operation. The presented methods of the clock mechanism synthesis can be useful for the design, maintenance and conservation of large-scale city astronomical clocks since these clocks represent a precious historical and cultural heritage of European civilization.

Flow pattern of accelerated cometary ions inside and outside the diamagnetic cavity of comet 67P/Churyumov-Gerasimenko

Analyzing data from the Ion Composition Analyzer on board the Rosetta spacecraft, we studied a flow pattern of accelerated cometary ions (40–80 eV) inside and outside the diamagnetic cavity of comet 67P/Churyumov-Gerasimenko (67P). We found that the accelerated ions are intermittently observed and are ten times more frequently observed outside the cavity than inside, and they mainly flow tailward with an aberration (~20–40°). We suggest that they are accelerated by the tailward polarization electric field upstream of the comet. Because their occurrence frequency becomes lowest near perihelion where the water production rate is highest at 67P, ion-neutral collisions and/or charge exchange may play a role in controlling the occurrence frequency. The aberration pattern is different inside and outside the cavity in the cometocentric solar equatorial (CSEQ) frame but it is consistent in the comet-Sun electric (CSE) frame; the latter is rotated from the CSEQ frame about the comet-Sun line so that the Z-axis is aligned with the local motional electric field. Because the flow pattern of the accelerated ions inside the cavity in the CSE frame is the same as outside, we suggest that the flow pattern inside is determined by the flow outside, depending on the local plasma and magnetic field. Near the CSE polar plane the aberration is in the opposite direction of the motional electric field, while it is in the anti-cometward direction near the CSE equator plane. The aberration in the anti-electric-field direction near the CSE polar plane suggests that the accelerated ions are mass-loaded by local cold cometary ions, just like the mass-loading of the solar wind by cold cometary ions. The cause of the anti-cometward aberration near the CSE equator plane is still unknown, but this may indicate that the tailward-flowing cometary ions are deflected across the upstream boundaries or by an outward-pointing ambipolar electric field.

Time evolution of accreting magnetofluid around a compact object-Newtonian analysis

Time evolution of a thick disc with finite conductivity around a nonrotating compact object is presented. Along with the Maxwell equations and the Ohm's law, the Newtonian limit of the relativistic fluid equations governing the motion of a finitely conducting plasma is derived. The magnetofluid is considered to possess only the poloidal components of the electromagnetic field. Moreover, the shear viscous stress is neglected, as well as the self-gravity of the disc. In order to solve the equations, we have used a self-similar solution. The main features of this solution are as follows. The azimuthal velocity is somewhat increased from the Keplerian value in the equator plane to the super-Keplerian values at the surface of disc. Moreover, the radial velocity is obtained proportional to the meridional velocity. Magnetofluid does not have any nonzero component of the current density. Subsequently, the electromagnetic force is vanished and does not play any role in the force balance. While the pressure gradient maintains the disc structure in latitudinal direction, magnetofluid has no accretion on the central compact object. Analogously to the parameter α in the standard model, our calculations contain one parameter η0 which specifies the size of the electrical resistivity.

Pole Figure Analysis for Fe-3% Si Silicon Steel

The principle and method of analysis of the crystallographic planes standard equator plane projection are described in this article. Under different technological using similar Fe-3% Si silicon steel samples, conventional grain oriented silicon steel, 1150°C conventional hot-rolled grain oriented silicon steel and non-oriented silicon steel are obtained, respectively. Their pole figures of {200} planes for the samples are also obtained with XRD. The results state that the conventional Fe-3% Si grain oriented silicon steel has good Gauss texture, and 1150°C conventional hot-rolled grain oriented silicon steel has weak Gauss texture, meanwhile, non-oriented silicon steel has no Gauss texture, which prove the process has great the effect on the texture.

Nukleophile Substitution an Thionyl- und Sulfurylchlorid mit Metallaten. Synthese und Struktur der SO- bzw. S 0 2-Komplexe [(C6H5O)3P]2(CO)2Fe(SOn)(n=1, 2) / Nucleophilic Substitution at Thionyl- and Sulfuryl Chloride by Metallates. Synthesis and Structure of the SO- and SO2-Complexes [(C6H5O)3P]2(CO)2Fe(SOn)(n=1, 2)

The synthesis of the SO- and SO2-complexes 3 and 4 follows equations (1) and (3) by nucleophilic substitution of SOCl2 or SO2Cl2 by the same metallate 2. 4 can also be obtained by simple air oxidation of solutions of 3 according to equation (2). Spectroscopic investigations indicate a trigonal bipyramidal configuration on iron with both phosphite ligands in axial positions and the sulfur oxide ligands in equatorial positions together with both carbonyl ligands. The X-ray structure analysis of the SO2 complex 4 shows the exactly planar coordination of the sulfur atom and the nearly perpendicular orientation of the SO2 plane to the equator plane; thus complex 4 is isolobal to SO3. The SO ligand in 3 coordinates as a 2c-2e-system in a bent structure with both atoms lying in the equatorial plane.