Synchronous process

Restricted Hartree-Fock calculations of the suprafacial addition of ethylene to l,4-dithioniabicyclo[2.2.0]hexane with the 6-31G basis failed to locate the transition state for this process. Synchronous suprafacial addition should... 

Synchronous fluorescence. Synchronous fluorescence stands for a type of fluorescence measurement technique in which the excitation and emission monochromator are scanned simultaneously and the constant wavelength difference between excitation and emission is maintained throughout the process. Synchronous spectra are a characteristic property of a molecule or compound and so the analyte can be detected selectively from a mixture or solution. 

They tie-up vast amounts of inventory and are the cause of stockpiling because they destroy process synchronization and thus create unnecessary laydays (waiting, downtime). 

We have already amply discussed the catastrophic effects on schedule effectiveness of capacities that have not been previously harmonized or the failure to recognize that individual components are missing. Delayed schedules always means an interruption of process synchronization and backlog And, this in turn binds inventory unnecessarily. 

When an additional radio frequency field B = lo cos cot is added with B Bq, the dipoles are forced to process synchroneously with the RF field B in the x-y-plane if co = coi. This results in a macroscopic magnetic moment M = Nfi, which rotates with co in the x-jp-plane and has a phase angle tt/2 against B (Fig. 2.33c). The precession of the atoms becomes coherent through their coupling to the RP field. In the quantum-mechanical description, the RF field induces transitions between the Zeeman sublevels (Fig. 2.33d). If the RF field B is sufficiently intense, the atoms are in a coherent superposition of the wave functions of both Zeeman levels. 

Waste of overproduction— reduced setup times, process synchronization, visibility... 

The process of mass transfer is repeated over and over to synchronize time intervals, used. 

The local dynamics of tire systems considered tluis far has been eitlier steady or oscillatory. However, we may consider reaction-diffusion media where tire local reaction rates give rise to chaotic temporal behaviour of tire sort discussed earlier. Diffusional coupling of such local chaotic elements can lead to new types of spatio-temporal periodic and chaotic states. It is possible to find phase-synchronized states in such systems where tire amplitude varies chaotically from site to site in tire medium whilst a suitably defined phase is synclironized tliroughout tire medium 51. Such phase synclironization may play a role in layered neural networks and perceptive processes in mammals. Somewhat suriDrisingly, even when tire local dynamics is chaotic, tire system may support spiral waves... 

The mechanism of the D-A rxn is believed to be a one-step, concerted, non-synchronous process. 

The Cardiac Cycle. The heart (Eig. lb) performs its function as a pump as a result of a rhythmical spread of a wave of excitation (depolarization) that excites the atrial and ventricular muscle masses to contract sequentially. Maximum pump efficiency occurs when the atrial or ventricular muscle masses contract synchronously (see Eig. 1). The wave of excitation begins with the generation of electrical impulses within the SA node and spreads through the atria. The SA node is referred to as the pacemaker of the heart and exhibits automaticity, ie, it depolarizes and repolarizes spontaneously. The wave then excites sequentially the AV node the bundle of His, ie, the penetrating portion of the AV node the bundle branches, ie, the branching portions of the AV node the terminal Purkinje fibers and finally the ventricular myocardium. After the wave of excitation depolarizes these various stmetures of the heart, repolarization occurs so that each of the stmetures is ready for the next wave of excitation. Until repolarization occurs the stmetures are said to be refractory to excitation. During repolarization of the atria and ventricles, the muscles relax, allowing the chambers of the heart to fill with blood that is to be expelled with the next wave of excitation and resultant contraction. This process repeats itself 60—100 times or beats per minute... 

Mutual Exclusion (MUTEX). The idea of multiple entities all working on the same piece of work raises this issue of coordination and communication among the individual processes. A weU-known example from banking is instmctive. Consider two bank tellers simultaneously performing withdrawals from the same bank account. Both read the account balance and determine that the balance is 100, and so a withdrawal of 100 is allowed. Both then withdraw 100 from the account. Clearly this process needs some means by which the actions of the independent processes can be synchronized and coordinated. 

The silicon-controlled rectifier with a dc motor has become predominant in adjustable-speed drives for almost all commonly used conveyors when speed adjustment to process conditions is necessary. The low cost of this control device has influenced its use when speed synchronization among conveyors is required. This can also be done, of course, by changing sheave or sprocket ratios. 

If the technical staff from the client company recognizes that a toller may be asked to perform new analyses and make operating decisions based upon the results, the client may help the toller develop the needed procedures and skills required to make these decisions. Typically a round robin laboratory qualification exercise will be performed. Samples of known standards and unknown concentrations of the materials to be analyzed for the toll will be prepared and sent to both laboratories. This can help ensure that equipment calibration is synchronized and that the toller is capable of performing accurate measurements. In some cases, the toller may be the party with the chemical, process, or synthesis specific expertise. 

With the help of bridle no. I driven by motors M and M4, the uncoiler section speed is controlled by monitoring the tension of the travelling sheet and hence maintaining constant speed of the sheet in the uncoiler section. The tensile difference of T tind Ti determines the speed of the uncoiler. Speed and tension of the sheet must remain constant for absolute synchronization between the uncoiler process and the recoiler sections. 

Consider a process plant having a connected load of 15 000 kW and a running load of 12 500 h.p. at almost 0.65 p.f. lagging. Let a few large induction motors aggregating 2000 h.p. be replaced by as many oversized synchronous machines, with the purpose of improving the system p.f. in addition to performing the motor s duties. 

Synchronization can only be accomplished with the emergency stop circuitry in the normal mode, previously described. If there is an emergency fault during the synchronization process, the e-stop contact will open and override the synchronization mode. 

The driver is a prime mover capable of developing the required torque at a constant speed or over a range of speeds. The driver s energy source can be either electrical or mechanical. Electrical energy is used by motors, either of the induction or synchronous type, while the mechanical covers a multitude of sources. It may be a fuel, as in internal or external combustion engines, or it may be a gas, such as steam or process gas used in a turbine or expander. 

Pollard, Eniest 1., Synchronous Motors. . . Avoid Torsional Vibration Problems, Hydrocarbon Processing, February 1980, pp. 97-102. 

There is an intermediate mechanism between these extremes. This is a general acid catalysis in which the proton transfer and the C—O bond rupture occur as a concerted process. The concerted process need not be perfectly synchronous that is, proton transfer might be more complete at the transition state than C—O rupture, or vice versa. These ideas are represented in a three-dimensional energy diagram in Fig. 8.1. 

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