Ticks

The tick-off heuristic. Once the matches around the pinch have been chosen to satisfy the criteria for minimum energy, the design should be continued in such a manner as to keep capital costs to a minimum. One important criterion in the capital cost is the number of units (there are others, of course, which shall be addressed later). Keeping the number of units to a minimum can be achieved using the tick-off heuristic. To tick off a stream, individual units are made as... 

Figure 16.5a shows the matches around the pinch from Fig. 16.4a with their duties maximized to tick-oflF streams. It should be emphasized that the tick-off heuristic is only a heuristic and can occasionally penalize the design. Methods will be developed later which allow such penalties to be identified as the design proceeds. 

Turning now to the cold-end design, Fig. 16.6a shows the pinch design with the streams ticked off. If there are any cold streams below the pinch for which the duties eu e not satisfied by the pinch matches, additional process-to-process heat recovery must be used, since hot utility must not be used. Figure 16.66 shows an additional match to satisfy the residual heating of the cold streams below the pinch. Again, the duty on the unit is maximized. Finally, below the pinch the residual cooling duty on the hot streams must be satisfied. Since there are no cold streams left below the pinch, cold utility must be used (Fig. 16.6c). 

Figure 16.6 Sizing the units below the pinch using the tick-off heuristic.

It is in fact the tick-off heuristic that steered the design toward the minimum number of units. The target for the minimum number of units was given by Eq. (7.2) ... 

Before any matches are placed, the target indicates that the number of units needed is equal to the number of streams (including utility streams) minus one. The tick-off heuristic satisfied the heat duty on one stream every time one of the units was used. The stream that has been ticked off is no longer part of the remaining design problem. The tick-off heuristic ensures that having placed a unit (and used up one of our available units), a stream is removed from the problem. Thus Eq. (7.2) is satisfied if eveiy match satisfies the heat duty on a stream or a utility. 

The loads on individual units are determined using the tick-off heuristic to minimize the number of units. Occasionally, the heuristic causes problems. 

Solution Figure 16.8a shows the hot-end design with the CP table. Above the pinch, adjacent to the pinch, CPfjSCPc- The duty on the units has been maximized according to the tick-oflF heuristic. 

The algorithm may calculate an increase in Qnmin and Qcmin- This means that the match is transferring heat across the pinch or that there is some feature of the design that will cause cross-pinch heat transfer if the design was completed. If the match is not transferring heat across the pinch directly, then the increase in utility will result from the match being too big as a result of the tick-off heuristic. 

Figure 16.215 shows an alternative match for stream 1 which also obeys the CP inequality. The tick-off" heuristic also fixes its duty to be 12 MW. The area for this match is 5087 m , and the target for the remaining problem above the pinch is 3788 m . Tlius the match in Fig. 16.216 causes the overall target to be exceeded by 16 m (0.2 percent). This seems to be a better match and therefore is accepted. 

The cold-utility target for the problem shown in Fig. 16.22 is 4 MW. If the design is started at the pinch with stream 3, then stream 3 must be split to satisfy the CP inequality (Fig. 16.22a). Matching one of the branches against stream 1 and ticking off stream 1 results in a duty of 8 MW. 

This is a case in which the tick-off" heuristic has caused problems. The match is infeasible, and its duty must be reduced to 6 MW to be feasible without either stream being ticked off (Fig. 16.226). 

Figure 16.22c shows an additional match placed on the other branch for stream 3 with its duty maximized to 3 MW to tick off stream 3. No further process-to-process matches are possible, and it remains to place cold utility. 

Figure 16.23a shows the complete design, achieving maximum energy recovery in one more unit than the target minimum due to the inability to tick off streams below the pinch. 

Deviated well (tick marks every 500ft) TD Total depth ft tvss Clay / claystone... 

Ticks triangles point towards downthrown block... 

In the Kx ten ded H tick el approx irn ation, lli c eh urges in th c u n selected part arc treated like classical point charges. The correction of these classical charges to the diagonal elcincntsof the Hamiltonian matrix may be written as ... 

Discovered by Gregor in 1791 named by Klaproth in 1795. Impure titanium was prepared by Nilson and Pettersson in 1887 however, the pure metal (99.9%) was not made until 1910 by Hunter by heating TiCk with sodium in a steel bomb. 

Any one bin can be electronically distinguished from the next one, and therefore the bins can be used like the tick of a standard clock. Each bin serves as one tick, which lasts for only 0.3 nsec. By counting the ticks and knowing into which bin the ion pulse has gone, the time taken for the ion to arrive at the detector can be measured to an accuracy of 0.3 nsec, which is the basis for measuring very short ion arrival times after the ions have traveled along the TOE analyzer tube. Each ion arrival pulse (event) is extracted from its time bin and stored in an associated computer memory location. 

The working of the CPU is controlled by a crystal clock having a frequency, generally, of 16 to 25 MHz, depending on the type of computer. All electronic moves are controlled by the clock and operate in sequence to its ticking. 

Duranol dyes Duranon Tick Repellent Duraphyl Dura Se bolus Durasoft Durazym Durene [95-93-2]... 

The Opiates. The International Narcotics Control Board—Vienna, tracks the tick production of narcotic dmgs and annually estimates world requkements for the United Nations. Thek most recent pubHcation (100) points out that more than 95% of the opium for Hcit medical and scientific purposes is produced by India and, in a declining trend, only about 600 t was utilized in 1988. This trend appears to be due to the fact that the United States, the largest user of opium for alkaloid extraction, reduced the amount of opium being imported from about 440 t in 1986 to 249 t in 1987 and 224 t in 1988. The United States used about 48 t of morphine (2, R = H) in 1988, most (about 90%) being converted to codeine (2, R = CH3) and the remainder being used for oral adrninistration to the terminally ill (about 2 t) and for conversion to other materials of minor commercial import which, while clearly alkaloid-derived, are not naturally occurring. 

P. A. Tick and P. L. Bocko, "Optical Fiber Materials," The Handbook of Optical Materials, Vol. 3, Marcel Dekker, New York, 1988. 

Table 11. Repellents for Mosquitoes, Flies, Mites, and Ticks ...

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