Pump power levels

Figure 7.3 Emission spectra from nanowire arrays below (line 1) and above (line 2) the lasingthreshold. The pump power levels for these spectra were 20 and lOOkWcm, respectively. The spectra are offset for easy comparison. The inset shows the spectrum for 150kWcm excitation density. (Courtesy of P.

However, when comparing different impeller types at the same power level, it turns out that impellers that have a higher pumping capacity will give decreased circulation time, but all the impellers, regardless of their pumping efficiency, give the same blend time at the... 

Loop Reactors For some gas-hquid-solid processes, a recirculating loop can be an effective reactor. These involve a relatively high horsepower pumping system and various kinds of nozzles, baffles, and turbulence generators in the loop system. These have power levels... 

Figure 16-16 shows the performance characteristic of a split-shaft turbine where the only power output limitation is the maximum allowable temperature at the inlet of the turbine section. In actual practice a torque limit, increased exhaust temperature, loss of turbine efficiency, aud/or a lubrication problem on the driven equipment usually preclude operating at very low power turbine speeds. The useful characteristic of the split-shaft engine is its ability to supply a more or less constant horsepower output over a wide range of power turbine speeds. The air compressor essentially sets a power level and the output shaft attains a speed to pnivide the required torque balance. Compressors, pumps, and various mechanical tinvc systems make very good applications for split-shaft designs. 

Total Pressure Loss. Since bit life is not an issue in a short deviation control motor run operation, it is desirable to operate the positive displacement motor at as high a power level as possible during the run. The motor has a maximum pressure loss with which it can operate. This is 580 psi (see Table 4-114). It will be assumed that the motor will be operated at the 580 psi pressure loss in order to maximize the torque output of the motor. To obtain the highest horsepower for the motor, the highest circulation flowrate possible while operating within the constraints of the surface mud pump should be obtained. To obtain this highest possible, or optimal, circulation flowrate, the total pressure losses for the circulation system must be obtained for various circulation flowrates. These total pressure losses tabulated in the lower row of Table 4-117 represent the surface standpipe pressure when operating at the various circulation flowrates. 

Sum-frequency mixing of two diode pumped fiber lasers (938 and 1583 nm) in a nonlinear crystal. CW format has been demonstrated at low power levels higher powers and pulsed formats are under development. 

After the preamplifier, the beam is expanded to 2 mm, collimated and imaged onto a 1 mm aperture, producing a flat-top intensity profile. A 3-element telescope relays the aperture plane to the amplifier with a collimated 0.5-mm diameter. The telescope contains a spatial filter pinhole. The nominal power levels are 3 mW into the preamp, 500 mW out of the preamp and 200 mW out of the aperture. A 6° angle of incidence bounce beam geometry is utilized in the amplifier cell. The "bounce" foofprinf overlaps with the 4 pump beam fibers, arranged in 2 time sefs of 13 kHz. The pump fibers have f 50-60% fransmission. The amplifier brings the power up to < 20 W at 26 kHz. 

Of course the only way to keep this 250W behemoth running for more than a minute without hitting the IC s internal OTP (over temperature protection) was to use a water-cooled heatsink, which my rather lab-ratty senior tech fashioned in less than half a day with some tubes, strips of metal, high-temp solder, and a sump (submersible pump). Note that the dissipation in the TO-220 was about 15W at this power level (calculated and measured). Yes, if you think that is a wee bit too much for a TO-220 to handle, I am on your side. 

Fig. 12.8 (a) The experimental setup, (b) Optical spectra emitted from a CBNL under different pump levels. Inset Integrated emitted power vs. pump power, showing laser threshold at 800 mW. Inset 2 Lasing pattern. Reprinted from Ref. 21 with permission. 2008 Institute of Electrical and Electronics Engineers... 

Optically-pumped lasers (OPLs) offer very useful power levels at discrete frequencies well into the THz band. Most OPLs comprise some sort of gas cell, which is the active laser medium, that is pumped by a carbon dioxide laser. These devices are inherently inefficient because the... 

In the experiments described thus far, the pump laser simply populates the intermediate excited state. The consequence is that the experiment becomes a means to study that excited state. Often we are more concerned with learning about the ground state than about excited states. For this purpose, it is useful to prepare a vibrational wavepacket of that ground state. One useful means to do this is to excite the species of interest to an allowed excited state and then to down-pump from that excited state back to the ground state, with a pulse that generates a packet rather than a stationary state. The simplest way to do this currently seems to be to raise the power level of the pulsed pump laser [26]. This process is shown schematically in Fig. 7. 

The power level can be switched from 10 to 650 W by the chosen cycle time. The temperature can be preset and subsequently controlled automatically between 0 and 120°C. Vacuum is generated by a built-in vacuum pump (operating at 12 V), producing 0.0-0.3 bar vacuum. The vacuum level is indicated by an automatic meter. Since the oven provides a sealed and ventilated system, the evaporation of formalin, ethanol, isopropanol, and other reagents does not affect the operator. Vapors and fumes are extracted by continuous ventilation. The oven weighs about 21 kg. Its use is awaited. 

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