Electric control

Certain glass-ceramic materials also exhibit potentially useful electro-optic effects. These include glasses with microcrystaUites of Cd-sulfoselenides, which show a strong nonlinear response to an electric field (9), as well as glass-ceramics based on ferroelectric perovskite crystals such as niobates, titanates, or zkconates (10—12). Such crystals permit electric control of scattering and other optical properties. 

The pH meter usually is coupled to a data recording device and often to a pneumatic or electric controller. The controller governs the addition of reagent so that the pH of the process stream is maintained at the desired level. 

An air valve, sometimes called the air-activated valve, is widely used for automated food handling operations. Although electronic or electric control boxes may be a part of the system, the valve itself generally is air-activated, and is more reflable than other types. Air-operated valves are used for in-place cleaning systems, and for the transfer and flow control of various products. 

Chemical treatments commonly appHed to cormgated paperboard packaging materials include additives that impart various degrees of water resistance, humidity resistance, oil and grease resistance, product abrasion resistance, product corrosion resistance, adhesion release properties, flame-retardant properties, nonskid properties, and static electricity control properties to the finished package (1,2). 

Current Flow Corona discharge is accompanied by a relatively small flow of electric current, typically 0.1 to 0.5 mA/m" of collecting-electrode area (projected, rather than actual area). Sparking usually involves a considerably larger flow of current which cannot be tolerated except for occasional periods of a fraction of a second duration, and then only when smtable electrical controls are provided to hmit the current. However, when suitable controls are provided, precipitators have been operated continuously with a small amount of sparking... 

In such conditions, it is recommended that the T-R be equipped with an electrical control circuit, which primarily keeps the potential constant, and, in exceptional circumstances, also the protection current. These pieces of equipment are potentiostats (for controlling potential) and galvanostats (for controlling current) [8]. 

Area designation Zoning for electrics Control portable heaters etc. No smoking Restricted areas... 

The accident resulted from a routine safety test of some electrical control equipment at the start of a normal reactor shutdown for routine maintenance. The test was to determine the ability to continue to draw electrical power from a turbine generator during the first minute of coast-down following a station blackout. In a blackout, the reactor automatically scrams and diesel generators start to assume load (about 1 minute required). 

Electric control An electrical device that controls some mechanical function, such as a damper control. 

Generally, electrical control systems are designed Fail-Safe. If power is temporarily lost, unnecessary shutdown of the process may occur. Thus, most safety systems such as fire and gas detectors, Nav-Aids, communications, and emergency lighting require standby D.C. power. 

Exterior Entrance Compressor and Generator Rooms Electrical Control Rooms Open Deck Areas 1, ower Catwalks... 

Electrical control and enclosures AIA, ANSI, ARI, CMA, FIA, FM, IEEE, ISA, NEMA, NFPA, NSC, OIA, OSHA, UL, USCG... 

MACC was established in 1967 and encompasses nearly 50,000 square miles from Virginia to New York. MAAC contains the PJM centrally dispatched electric control area, which is the largest such area in North America and the third largest in the world. PJM Interconnection became the first operational independent system operator in the United States on Januai y 1, 1998. 

A magnetic field due to an electric current can be turned on and off simply by turning the current on and off. A piece of iron attached to the end of a spring having the other end fixed can be moved with a magnetic field and returned to its initial position by the spring. The iron piece can then be used to actuate a switch or move a lever on a valve. Applications of this principle include electrically controlled valves in a washing machine and an electrically controlled switch for the starter in an automobile. 

Telephones/intercom Protection equipment Electrical controls, inst. meters Lighting and small power Temporary supplies Elec, hace heating Generator AVR... 

Figure 31.4 Electrical control diagram for small air-conditioning system...

Check all wiring and electrical controls, for correct circuitry, security of terminals, continuity, insulation, compliance with safety regulations such as lEE, marking of terminals and cables, etc. Check action of all controls as far as may be possible without running any item [63]. 

Knowledge of electrical controls and interlocks House close by, prepared to work on call ... 

The wick of the sample paper can either be ignited before the stopper is placed in the flask neck, or better still ignited by remote electrical control, or by an infrared lamp. In any case combustion is rapid and usually complete within 5-10 seconds. After standing for a few minutes until any combustion cloud has disappeared, the flask is shaken for 2-3 minutes to ensure that complete absorption has taken place. The solution can then be treated by a method appropriate to the element being determined. 

In order to compensate for the distortions in the wavefront due to the atmosphere we must introduce a phase correction device into the optical beam. These phase correction devices operate by producing an optical path difference in the beam by varying either the refractive index of the phase corrector (refractive devices) or by introducing a variable geometrical path difference (reflective devices, i.e. deformable mirrors). Almost all AO systems use deformable mirrors, although there has been considerable research about liquid crystal devices in which the refractive index is electrically controlled. 

This chapter is devoted to the behavior of double layers and inclusion-free membranes. Section II treats two simple models, the elastic dimer and the elastic capacitor. They help to demonstrate the origin of electroelastic instabilities. Section III considers electrochemical interfaces. We discuss theoretical predictions of negative capacitance and how they may be related to reality. For this purpose we introduce three sorts of electrical control and show that this anomaly is most likely to arise in models which assume that the charge density on the electrode is uniform and can be controlled. This real applications only the total charge or the applied voltage can be fixed. We then show that predictions of C < 0 under a-control may indicate that in reality the symmetry breaks. Such interfaces undergo a transition to a nonuniform state the initial uniformity assumption is erroneous. Most... 

Burgmayer and Murray [40] reported electrically controlled resistance to the transport of ions across polypyrrole membrane. The membrane was formed around a folded minigrid sheet by the anodic polymerization of pyrrole. The ionic resistance, measured by impedance, in 1.0 M aqueous KC1 solution was much higher under the neutral (reduced) state of the polymers than under the positively charged (oxidized) state. The redox state of polypyrrole was electrochemically controlled this phenomenon was termed an ion gate, since the resistance was varied from low to high and vice versa by stepwise voltage application. 

AM Weiss, AJ Grodzinsky, ML Yarmush. Chemically and electrically controlled membranes Size specific transport of fluorescent solutes through PMAA membranes. AlChE Symp Ser 82 85-98, 1986. 

K Sawahata, M Hara, H Yasunaga, Y Osada. Electrically controlled drug delivery system using polyelectrolyte gels. J Controlled Release 14 253-262, 1990. 

Muscles (heart, etc.) Stomach/intestine Liver Kidney (bowel) Reproductive organs Glands Brain (Chapter 9) Sense organs Digestion, fluid circulation, motion, mechanical work Major zones of digestion Major zone of synthesis Major external rejection ion/water balance Reproduction Chemical controls Electrical control Environmental detectors... 

---