Pulsating field

When a process is produced under the divergent or convergent action of two different forces, the ratio between them represents a dimensionless number. The heat and mass transfer enhanced by the supplementary action of a pulsating field (vibration of apparatus, pulsation of one (or two) phase flow(s), ultrasound action etc.) has been experimented and applied in some cases [6.25-6.27]. Then, the new... 

Induced currents, using electromagnetic or electrostatic fields, bypass the problem of having to implant electrodes and eliminate necrosis of tissue by anodic currents. However, inducing currents in tissue requires the use of pulsating fields. 

Electronic manipulation, such as described, is not difficult. However, it has been found that pulsating fields act on cells in a more complex manner than direct current, i.e., steady state fields. Cellular interaction is dependent upon pulse width and frequency as well as amplitude. Thus, so-called windows have been described in which imposed pulsatile fields are effective for cellular stimulation, as well as inhibition. In general, pulsatile frequencies greater than approximately 500 Hz are not effective. For bone growth, frequencies of <100 Hz are used, with different investigators suggesting 5-20 Hz, 30-40 Hz, or 70-80 Hz as optimal for growth stimulation. 

Pulsating field Once rotation is established, the pulsating field in the run... 

Flow which fluctuates with time, such as pulsating flow in arteries, is more difficult to experimentally quantify than steady-state motion because phase encoding of spatial coordinate(s) and/or velocity requires the acquisition of a series of transients. Then a different velocity is detected in each transient. Hence the phase-twist caused by the motion in the presence of magnetic field gradients varies from transient to transient. However if the motion is periodic, e.g., v(r,t)=VQsin (n t +( )q] with a spatially varying amplitude Vq=Vq(/-), a pulsation frequency co =co (r) and an arbitrary phase ( )q, the phase modulation of the acquired data set is described as follows ... 

The plus sign indicates a positive sequence harmonic and the minus. sign a negative sequence harmonic. Their effect is same as for the positive and the negative seqtience components discussed in Section I2.2(v) and ctiuses pulsation in the magnetic field and hence, in the torque of a rotiitimi machine. 

For smaller, high-speed compressors the piping sizing rules of thumb discussed above, in conjunction with pulsation bottles sized from Figure 11 -24, should be sufficient for individual field compressors. These niles of thumb can also be used for preliminary sizing of piping and bottles in preparation for an analog study. 

Compound-Wound Motors. These motors are used to drive machines that require high starting torque or in which the loads have a pulsating torque. Changes in load usually produce wide speed regulation. This motor is not suited for adjustable speed by field control. 

Abstract Acoustic cavitation is the formation and collapse of bubbles in liquid irradiated by intense ultrasound. The speed of the bubble collapse sometimes reaches the sound velocity in the liquid. Accordingly, the bubble collapse becomes a quasi-adiabatic process. The temperature and pressure inside a bubble increase to thousands of Kelvin and thousands of bars, respectively. As a result, water vapor and oxygen, if present, are dissociated inside a bubble and oxidants such as OH, O, and H2O2 are produced, which is called sonochemical reactions. The pulsation of active bubbles is intrinsically nonlinear. In the present review, fundamentals of acoustic cavitation, sonochemistry, and acoustic fields in sonochemical reactors have been discussed. 

In a multibubble field, every pulsating bubble radiates secondary acoustic wave called acoustic cavitation noise. The pulsation of a bubble is driven by both the primary ultrasound and the acoustic cavitation noise. The influence of the latter on the bubble pulsation is called bubble-bubble interaction [89, 90]. Generally speaking, the bubble-bubble interaction suppresses the bubble expansion as shown in Fig. 1.16 [38, 89-91]. Further studies are required on this topic. 

Fig. 1. Result from the subset analysed so far. The data are binned in metallicity to reflect the typical uncertainty on our determination of [Fe/H], marked by horizontal error-bars. The median value of 5(My) in each metallicity bin is plotted as filled squares, with the vertical error-bars representing its associated error. For comparison we also plot the empirical results from [5] in two Cepheid fields in Ml 01 (open circles and solid line) and the theoretical predictions by [2] from non-linear pulsational models (dashed line)...

Microturbulence seldom occurs alone it is generally driven by larger-scale motions microturbulence is the high-wavenumber part of the atmospheric spectrum of turbulence. For the stars discussed here the origin of the motion field may be found in pulsations or in convective motions. Such motions have been discovered in a Cyg (Boer et al., 1987 ) they have up- and downward velocities of 14 km s-1 and the... 

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