Maximum achievable power

We all know that the losses in the output capacitor of any Flyback are high, due to the choppy waveform of the current they encounter coming through the diode. It is obvious that reducing the ESR to zero would totally knock off a major chunk of losses, boost the published efficiency curves, and allow a much higher maximum achievable power for the device. However, OmQ would have been much too obvious, wouldn t it So it was a case of Buck the ESR and Boost the efficiency. In other words, a perfect Buck-Boost. 

In system C, many stacks are connected in series. Very small currents are generated at still higher voltages. As the number of stacks in series is increased, the maximum achievable power quickly approaches the power which a reversible system would generate, i.e. complete conversion of the available free energy. (A reversible system is reversible at every point in each stack, not just at the stack outlets.) The shaded area in the graph nearly fills the entire area under the curve - the reversible power. 

Fig. 16. Maximum achievable signal-to-noise ratio (SNR) on read-out of different writable optical data storage systems as a function of the writing energy (laser power) (121). SQS = Organic dye system (WORM) PC = phase change system (TeSeSb) MO = magnetooptical system (GbTbFe). See text.

Figure 5.2. Two of the more common types of low pressure CVD reactor, (a) Hot Filament Reactor - these utilise a continually pumped vacuum chamber, while process gases are metered in at carefully controlled rates (typically a total flow rate of a few hundred cubic centimetres per minute). Throttle valves maintain the pressure in the chamber at typically 20-30 torr, while a heater is used to bring the substrate up to a temperature of 700-900°C. The substrate to be coated - e.g. a piece of silicon or molybdenum - sits on the heater, a few millimetres beneath a tungsten filament, which is electrically heated to temperatures in excess of 2200 °C. (b) Microwave Plasma Reactor - in these systems, microwave power is coupled into the process gases via an antenna pointing into the chamber. The size of the chamber is altered by a sliding barrier to achieve maximum microwave power transfer, which results in a ball of hot, ionised gas (a plasma ball) sitting on top of the heated substrate, onto which the diamond film is deposited.

In the case of InP-GalnAsP buried ridge structure lasers, continuous threshold currents of 8.2 mA at 300 K have been achieved (Kazmierski et al., 1989). This value compares favorably with the thresholds around 10 mA when proton implantation is used for insulation of the same structure. High maximum output power above 15 mW CW per facet and good maximum external quantum efficiency of 0.25 were found on the plasma hydrogenated structures. 

Equations (l)-(4) are used here essentially to illustrate the intricate interdependence between the maximum achievable field, the employed electric power, the maximum slewing rate dBjdt and the geometric parameters of the solenoid. A detailed, quantitative treatment (which must necessarily be carried out when designing an actual magnet) is beyond the scope of this review since, for example, the calculation of G and L for a real magnet is quite complex and requires numerical methods. 

The design parameters therefore always represent a compromise between the maximum achievable field and satisfactory slewing rates. The compromise can be resolved once one has defined the maximum available power, the basic geometry of the solenoid (in particular its volume), and any optimization constraints (see the next point). 

On the basis of Eq. (2), it is evident that the lower silver resistivity proportionally reduces the electrical power required to produce a given field. At the same time, it reduces the time constant RjL of the magnet which is an important factor in minimizing the final field-switching times. Section IV C discusses how the magnet time constant RjL and the power supply output voltage affect the maximum achievable slewing rate dBjdt. 

It is evident that, for a given magnet, it is the maximum power supply voltage which determines the maximum field-slewing rates and switching times while, according to Eq. (2), the maximum available power determines the maximum achievable field. 

The conditions used were those from which Fig. 32 is based. With Pr = 5 x 104 and the abscissa value I It Pr (H/D)-1 = 2.82 x 108, the optimum conditions Reopt Pr1/2 = 4.8 x 103 and the ordinate value (n2)opt= 8 x 101 follow from the work-sheet, producing nopt = 20 min-1 and Rmax = (R/V)opt V = 28.5 kW (see the optimum operating point in Fig. 32). At this stirrer speed the stirrer power amounts to ca. 6 kW, which is ca. 20% with respect to the maximum removal of reaction heat. From the auxiliary diagram in inset (b), it can be inferred that the rotation speed interval, in which at least 90% of the maximum achievable value (R90% = 25.6 kW) could be removed, lies between 8 and 32 min-1. 

The Maximum Achievable Control Technology (MACT) emission limitations required by the 1990 Clean Air Act Amendments (CAAA) show the ultimate effect of the ratcheting process. After a little more than two decades of ratcheting, MWCs have become a comparatively minor source of combustion-related air pollution. Other artificial and natural sources such as automobiles, trucks, power plants, fireplaces, wood stoves, metal production furnaces, industrial manufacturing processes, volcanoes, forest fires, and backyard trash burning are now the major known sources of combustion-related pollutants. 

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