Relay method

Lusardi (Ref 24) describes in Section 300 analytical procedures for the following compositions used in pyrotechnics igniter, first fire, flash, matchhead, delay and relay Method No 320. Igniter Composition, Aircraft Signal Type - Red lead 33-1/3, CuO 33-1/3 Si 33-1/3 [US Army Spec No 50-55-9 (1946)1... 

The majw work to date on synthetic applications of remote functionalization has involved free radical chlorination. The earliest studies involved the direct attachment of aryliodine dichloride units to the steroid substrates, then intramolecular free radical chain chlorination in benzene or chlorobenzene solution (Scheme 14). Yields were only in the 50% region, but fairly good selecdvities were observed compound (6) afforded chiefly the 9-chloro derivative, while compound (7) produced the 14-chloro steroid. The yields and selectivities were considerably improved when it was realized that aromatic solvents promote intermolecular random processes by forming complexes with C1-, and when the radical relay method was developed. 

An alternative closed-loop approach called the relay method uses temporary narrow limits on the controller output and toggles between output limits each time the controller error changes sign. The ultimate period is determined as before and the ultimate gain is computed as Ku = 4process measurement, both in percent. 

They did not know, of course, which enantiomer would be more active but it turned out that the methyl ester 257 was the right choice. Conversion to the amide 258 and aminal formation with pivalaldehyde 259 allowed control of enolate alkylation by Seebach s relay method (chapter 30). Hydrolysis of 260 and reaction with C1S02NC0 gave one enantiomer45 of 251. 

Slightly more than one year after the completion of the two formal total syntheses of cortisone by Robinson and Woodward there appeared a report by Sarett et al. (1952), describing a total synthesds of cortisone in the truest sense of the word. In contrast to the preceding two formal syntheses which utilized the relay method by synthesizing a certain steroid which had already been converted previously to cortisone, Sarett s synthesis meets the most rigorous criterion by leading directly to d -cortisone, thus excluding the use of a known (and hence optically active) steroid as an intermediate. 

An alternative approach to adjusting Kp by trial-and-error to attain sustained oscillation is to apply the Relay Method (Reference 5). This involves first selecting acceptable low and... 

Sonic Methods A fixed-point level detector based on sonic-propagation characteristics is available for detection of a liquid-vapor interface. This device uses a piezoelectric transmitter and receiver, separated by a short gap. When the gap is filled with liquid, ultrasonic energy is transmitted across the gap, and the receiver actuates a relay. With a vapor filling the gap, the transmission of ultrasonic energy is insufficient to actuate the receiver. 

Overload Protection Overload relays lor protecting motor insulation against excessive temperature are located either in the motor control or in the motor itsell. The most common method is to use thermal overciirrent relays in the starter. These relays have heating characteristics similar to those ol the motor which they are intended to protect. Either motor current or a current proportional to motorline current passes through the relays so that relay heating is comparable to motor heating. 

In this case the relay is in the form of a bridge circuit and thermal detection is achieved through various methods other than a bi-metallic heater element discussed below. 

A logical controller is thus a more effective method of replacing the auxiliary relays and is capable of performing many more functions instantly. 

This is a highly recommended method of capacitor switching for installations that are large and require very fine monitoring and correction of p.f. with the smallest number of banks. The entire reactive requirement is arranged in only a few steps yet a small correction up to the smallest capacitor unit is possible. The relay is sequenced so that through its binary counter the required switching is achieved in small steps, with just four or six sets of capacitor units or banks. The operation of the entire sequence can be illustrated as follows ... 

The information content resulting from both processing methods is identical insofar as correlation information is concerned. The matrix-square-root transformation can minimize artefacts due to relay effects and chemical shift near degeneracy (pseudo-relay effects80-82 98). The application of covariance methods to compute HSQC-1,1-ADEQUATE spectra is described in the following section. 

In 2003, Sprang and Bigler have developed a pulse sequence, HMBC-RELAY, subsequently improved in 2004, that yields two simultaneously detected types of long-range correlation spectra.60,61 One spectrum shows all 7ch connectivities while the other shows exclusively 2/ch connectivities. Their method uses homonuclear 3/hh couplings between the protons of adjacent carbons, as already been exploited for the XCORFE... 

In this method, Furstner converts N-BOC protected pyrrole to the 2,5-dibromo compound (122) with NBS and this is followed by metalation and carbomethoxylation with t-butyl lithium in THF and subsequent trapping of the metalated species with methyl chloroformate to yield a pyrrole diester (123). Bromination of this diester at positions 3 and 4 with bromine in water followed by Suzuki cross-coupling with 3,4,5-trimethoxyphenyl boronic acid yields the symmetrical tetrasubstituted pyrrole (125). Base-mediated N-alkylation of this pyrrole with 4-methoxyphenethyl bromide produces the key Boger diester (126) and thereby constitutes a relay synthesis of permethyl storniamide A (120). 

Hyphenated heteronuclear shift correlation methods Many of the experiments described thus far can be used as building blocks to create more sophisticated pulse sequences. The earliest variants of hyphenated NMR experiments, such as HC-RELAY, were heteronuclear detected [56]. More recent hyphenated heteronuclear shift correlation methods are based on proton detection and include... 

No a priori knowledge of the system time constants is needed. The method automatically results in a sustained oscillation at the critical frequency of the process. The only parameter that has to be specified is the height of the relay step. This would typically be set at 2 to 10 percent of the manipulated variable range. 

This method can be extended to evaluate models with more parameters and with diHerent kinds of transfer functions (e.g., underdamped second-order lag) by using hysteresis in the relay feedback or by inserting an additional dead time in the loop to produce a limit cycle with a different frequency. The two autotune tests give four equations so four parameters can be evaluated. 

Simulate several first-order lag and second-order lag plus deadlime processes on a digital computer with a relay feedback. Compare the ultimate gains and frequencies obtained by the auto-tune method with the real values of cu and obtained from the transfer function. 

Bill, I think this is a multivibrator and not a relay at all. It was the pre-solid state method of making an AC signal out of a DC input, probably from an old telephone system or vacuum tube driver. You will note that there are no connections from the coils to any of the terminals, except through the contacts (I expect the coils are connected to their respective end contacts). So both contacts on one side will be closed to complete a circuit - when power is applied these contacts will open and the opposite pair close and it just keeps doing this at its resonate frequency. There is one thing for sure - it is not operating as a relay in any way at all. 

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