Controlled-NOT operation

Gershenfeld and Chuang s two-qubit system [101] uses an NMR machine and the protons in 25. They demonstrated a nonlinear interaction between spins, a prerequisite for quantum logic gates. This was realized through the controlled-NOT operation (CNOT) which conditionally flips one spin based on the value of another [102], This gate can be considered as a quantum XOR gate. 

Temperature controller not operating correctly Carryover of water from inlet separator Inaccurate reboiler thermometer... 

Thus, a computer attached to a mass spectrometer must operate on two levels. When mass spectral information is arriving, this must be acquired in real time. When the computer has spare time, it controls the operation of the instrument. Both operations are carried out at such a high speed that the dual level of computer tasks is not obvious. 

Air Supply. Oxygen in excess of stoichiometric requirements for complete combustion is needed because incineration processes are not 100% efficient and excess air is needed to absorb a portion of the combustion heat to control the operating temperature. In general, units that have higher degrees of turbulence such as Hquid injection incinerators require less excess air (20 to 60%) while units with less mixing such as hearth incinerators require... 

These tests must encompass the complete interlock system, from the measurement devices through the final control elements. Merely simulating inputs and checking the outputs is not sufficient. The tests must duplicate the process conditions and operating environments as closely as possible. The measurement devices and final control elements are exposed to process and ambient conditions and thus are usually the most hkely to fail. Valves that remain in the same position for extended periods of time may stick in that position and not operate when needed. The easiest component to test is the logic however, this is the least hkely to fail. 

Limited Data First, plant data are limited. Unfortunately, those easiest to obtain are not necessarily the most useful. In many cases, the measurements that are absolutely required for accurate model development are unavailable. For those that are available, the sensitivity of the parameter estimate, model evaluation, and/or subsequent conclusion to a particiilar measurement may be very low. Design or control engineers seldom look at model development as the primaiy reason for placing sensors. Further, because equipment is frequently not operated in the intended region, the sensitive locations in space and time have shifted. Finally, because the cost-effectiveness of measurements can be difficult to justify, many plants are underinstru-mented. 

Iron and steel industries have been concerned with emissions from their furnaces and cupolas since the industry started. Pressures for control have forced the companies to such a low level of permissible emissions that some of the older operations have been closed rather than spend the money to comply. The companies controlling these operations have not gone out of business but rather have opened a new, controlled plant to replace each old plant. Table 6-3 illustrates the changes in the steelmaking processes that have occurred in the United States. 

The most widely used pulping process is the kraft process, as shown in Fig. 6-11, which results in recovery and regeneration of the chemicals. This occurs in the recovery furnace, which operates with both oxidizing and reducing zones. Emissions from such recovery furnaces include particulate matter, very odorous reduced sulfur compounds, and oxides of sulfur. If extensive and expensive control is not exercised over the kraft pulp process, the odors and aerosol emissions will affect a wide area. Odor complaints have been reported over 100 km away from these plants. A properly controlled and operated kraft plant will handle huge amounts of material and produce millions of kilograms of finished products per day, with little or no complaint regarding odor or particulate emissions. 

BWRs do not operate with dissolved boron like a PWR but use pure, demineralized water with a continuous water quality control system. The reactivity is controlled by the large number of control rods (>100) containing burnable neutron poisons, and by varying the flow rate through the reactor for normal, fine control. Two recirculation loops using variable speed recirculation pumps inject water into the jet pumps inside of the reactor vessel to increase the flow rate by several times over that in the recirculation loops. The steam bubble formation reduces the moderator density and... 

Instructions concerning safety and environmental issues should be integrated into the control and operating procedures such that the instructions are given at the stage in the process when they apply. In this way staff do not have to consult several documents and the chance of error is reduced. 

The documents that define the calibration process themselves are derived documents and therefore will be governed by your control procedure. They do not need to be listed along with all your other control and operating procedures in the index of quality system documents. A separate index of calibration methods should be maintained. Calibration methods are like test and inspection procedures, they are product specific. 

Alarm signals may come from the output signal used to control an operational valve. Shutdown signals should come from a completely separate instrument not dependent upon a normally used output signal for operation. 

Today it is usually harder than in the early days of computer control for operators to interfere with the software, override interlocks, or type in coiTect readings. However, many operators acquire keys or passw ords that they should not have, in much the same way as operators have always unofficially acquired and secreted an assortment of tools and adaptors. On one plant an interlock was found to be illegally blocked the password had been disclosed to 40 people, all of whom denied responsi-aility (see Section 14.5 d). 

The control room operator has directed the field operator to isolate the failed condenser as quickly as possible so that a imit shutdown will not be necessary. 

I. Space Heaters. A resistive heating device installed in the motor to prevent condensation when the motor is not operating. This requires a special control system. 

---