Reset cycle

Fig. 6.13. Memory device characteristics during 18 successive SET-RESET cycles (lower trace). The values of the high and low impedance states, 10 ohms and 20 ohms, respectively, are shown in the upper trace. The READ pulses are triggered at different times to show the stability of the impedance values under repetitive cycling. Memory material is GejoAs4oTe5Q. After Bunton and Quilliam (1973).

The stability, life, and reproducibility of typical threshold and memory switches have recently been reviewed by Ovshinsky and Fritzsche (1973). The statistical fluctuation of is about a few percent of for threshold switches and 5% for memory switches. Individual memory switches were subjected to more than 10 set-reset pulse trains as those shown in Figure 6.4(b) without failure. A whole 16X16 memory array of Figure 6.13 has presently an average failure free life of 2X 10 set-reset cycles. Memory devices were found to remain in the set or in the reset condition without change while being subjected to 10 read cycles over the period of one year (Neale and Aseltine (1973)). 

The loop therefore becomes slower and less stable at the same time. This resonance is sometimes called a reset cycle since it would not exist if the controller did not have automatic reset. 

The conjugate direction is reset to the steepest descent direction every 3N search direction s or cycles, or if the en ergy rises between cycles. 

For quadratic functions this is identical to the Fletcher-Reeves formula but there is some evidence that the Polak-Ribiere may be somewhat superior to the Fletcher-Reeves procedure for non-quadratic functions. It is not reset to the steepest descent direction unless the energy has risen between cycles. 

Reset alarms with process cycle, but only after all alarms have been acknowledged... 

Provision must be made in the wiring to maintain power to the standby pump driver. This will prevent power interruption due to the pressure switch contacts opening when lubricant pressure is restored. Cycling of the standby pump will occur if the circuit is not maintained. A reset will have to be furnished to permit shutting down the standby pump when the main pump is back on stream. 

Figure 22.1 Pathways projecting to and from the suprachiasmatic nucleus (SCN). Inputs from photoreceptors in the retina help to reset the circadian clock in response to changes in the light cycle. Other inputs derive from the lateral geniculate complex and the serotonergic, Raphe nuclei and help to reset the SCN in response to non-photic stimuli. Neurons in the SCN project to the hypothalamus, which has a key role in the regulation of the reproductive cycle, mood and the sleep-waking cycle. These neurons also project to the pineal gland which shows rhythmic changes in the rate of synthesis and release of the hormone, melatonin...

For processes that can operate with continuous cycling, the relatively inexpensive two position controller is adequate. For processes that cannot tolerate continuous cycling, a proportional controller is often employed. For processes that can tolerate neither continuous cycling nor offset error, a proportional plus reset controller can be used. For processes that need improved stability and can tolerate an offset error, a proportional plus rate controller is employed. 

Similarly if you toggle the enable pin at a certain rate in many ICs you can get to see current overshoots too. This often depends on allowing the input capacitor to discharge below the UVLO threshold, but not to the point where it hits the internal POR (power on reset) threshold. Because in that case, if you suddenly enable the IC, it has no soft-start anymore, and you will hit max duty cycle, and possibly staircase if the current limit circuitry is not well designed. 

ATP is used not only to power muscle contraction, but also to re-establish the resting state of the cell. At the end of the contraction cycle, calcium must be transported back into the sarcoplasmic reticulum, a process which is ATP driven by an active pump mechanism. Additionally, an active sodium-potassium ATPase pump is required to reset the membrane potential by extruding sodium from the sarcoplasm after each wave of depolarization. When cytoplasmic Ca2- falls, tropomyosin takes up its original position on the actin and prevents myosin binding and the muscle relaxes. Once back in the sarcoplasmic reticulum, calcium binds with a protein called calsequestrin, where it remains until the muscle is again stimulated by a neural impulse leading to calcium release into the cytosol and the cycle repeats. 

Light resetting of the circadian oscillator is at least partly mediated by light-induced transcription of a cycling clock component (Wang Tobin 1998) (Fig. 1). CCAl and LHY are two myb domain-containing transcription factors. 

The regulatory system of a cell cycle section can be reset to the groimd state by proteolysis. 

Neurohumoral (extrinsic) compensation involves two major mechanisms (previously presented in Figure 6-7)—the sympathetic nervous system and the renin-angiotensin-aldosterone hormonal response—plus several others. Some of the pathologic as well as beneficial features of these compensatory responses are illustrated in Figure 13-2. The baroreceptor reflex appears to be reset, with a lower sensitivity to arterial pressure, in patients with heart failure. As a result, baroreceptor sensory input to the vasomotor center is reduced even at normal pressures sympathetic outflow is increased, and parasympathetic outflow is decreased. Increased sympathetic outflow causes tachycardia, increased cardiac contractility, and increased vascular tone. Vascular tone is further increased by angiotensin II and endothelin, a potent vasoconstrictor released by vascular endothelial cells. The result is a vicious cycle that is characteristic of heart failure (Figure 13-3). Vasoconstriction increases afterload, which further reduces ejection fraction and cardiac output. Neurohumoral antagonists and vasodilators... 

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