Cycloid

Rad-kranz, m. (wheel) rim, tire. -Unie, /. cycloid. -reif,-reifen, m. tire rim. -schlauch,... 

The rotary lobe compressor stage is a rather low-pressure machine. These compressors do not compress gas internally in a fixed sealed volume as in other rotaries. The straight lobe compressor uses two rotors that intermesh as they rotate (see Figure 3-79). The rotors are timed by a set of timing gears. The lobe shapes may be involute or cycloidal in form. The rotors may also have two or three lobes. As the rotors turn and pass the intake port, a volume of gas is trapped and carried between the lobes and the housing of the compressor. When the lobe pushes the gas toward the outlet port, the gas is compressed by the back pressure in the gas discharge line. 

Ions generated by an electron beam from a heated filament are passed into a cubic cell where they are held by an electric trapping potential and a constant magnetic field. Each ion assumes a cycloidal orbit at its own characteristic frequency, which depends on mJz the cell is maintained under high vacuum. Originally, these frequencies were scanned by varying the electric field until each cycloidal frequency was, in turn, in resonance with an applied constant radiofrequency. At resonance, the motion of the ions of the same frequency is coherent and a signal can be detected. 

The newer instruments (Figure 2.4c) utilize a radiofrequency pulse in place of the scan. The pulse brings all of the cycloidal frequencies into resonance simultaneously to yield a signal as an interferogram (a time-domain spectrum). This is converted by Fourier Transform to a frequency-domain spectrum, which then yields the conventional m/z spectrum. Pulsed Fourier transform spectrometry applied to nuclear magnetic resonance spectrometry is explained in Chapters 4 and 5. 

Figure 7. a) excitation of a coherent packet of ions b) a coherently cycloiding packet of ions which induces the image current signal. 

Figure 9.16. The path of the Planck scan circle center when the precession angle is 15° and the precession rate is 10 cycles per year. The difference between the Northern and Southern loops of the cycloid causes the asymmetry in the coverage pattern seen in Figure 9.15.

In a second paper (43) y Werner reiterated his belief that the cycloid structure of Liebermann s theory (21) does not explain the peculiar properties of lakes, as it only affords the metal an opportunity of combining with the organic body by means of its primary valencies. 

There are many other interesting loci, for example the cycloid. 

The R/V Melville leaked cycloid oil during two diflFerent legs of its Pacific Ocean voyage. The cycloid oil was compared with samples collected at those times and was markedly difiFerent in composition. Therefore, there was no reason to believe that contamination with leaking cycloid oil had occurred. 

A cycloidal mass spectrometer was devised by Bleakney and Hipple which operates with crossed magnetic and electrostatic fields. Measurements by other workers show that with a magnetic field of 5000 gauss, masses 1-500 can be detected. Adjacent mass numbers are separable up to 100, but the resolution decreases for higher mass numbers. Partial pressure detection down to 10" torr is claimed. 

Roll a disc horizontally. Then, a given point on its rim will trace out a cycloid curve... 

Eckert B, Gottfries CG, Knorring L, Oreland L, Wilbert A, Winblad B (1980) Brain and platelet monoamine oxidase in schizoprenics and cycloid psy-chotics. Prog Neuropsychopharmacol 4 57-68... 

Simple artificial examples of sinusoidal, helical and cycloid magnetic structures are given in Figure 3.4. In Figure 3.5 there is a real example of the incommensurate conical structure of DyMugGcg propagation vector ki = (0,0,0) and k2 = (0,0,5) at the interior of Brillouin Zone. 

Figure 3.4 Examples of magnetic structures. In all cases the orientation of the lattice is similar, except in the second view of (b), where the point of view is nearly along a. (a) Sinusoidal structure with propagation vector k = (0,, 0) and Sk = (0,0,w). (b) Helical, or spiral, structure with propagation vector k = (0,(5,0) and Sk = (w/,0,w). (c) Cycloidal structure with propagation vector k = (0,, 0) and Sk = (0,u,ui).

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