Clock Time

Here R=r is the parameter for radiative heat transfer in K units, p is a heat of reaction term, in K/atm units tj is the fluid temperature in the j-th axial position e is the particle emissivity 1 is the celt dimension in m 6 is the clock time in minutes... 

Although direct methods for small and medium size systems require more CPU time than disk based methods, this is in many cases irrelevant. For the user the determining factor is the time from submitting the calculation to the results being available. Over the years the speed of CPUs has increased much faster than the speed of data transfer to and from disk. Many modem machines have quite slow data transfer to disk compared to CPU speed. Measured by the elapsed wall clock time, disk based HF methods are often the slowest in delivering the results, despite the fact that they require the least CPU time. 

Simply speaking, the CPU may be spending most of its time waiting for data to be transferred from disk. Direct methods, on the other hand, use the CPU with a near 100% efficiency. For machines without fast disk transfer (like workstation type machines) the crossover point for direct vs. conventional methods in terms of wall clock time may be so low that direct methods are always preferred. 

Note that some recorders have a clock time difference between the dry bulb and rh to allow for pen overlap. 

Assume that we have a program we will run on np processors and that this program has a serial portion and a parallel portion. For example, the serial portion of the code might read in input and calculate certain global parameters. It does not make any difference if this work is done on one processor and the results distributed, or if each processor performs identical tasks independently this is essentially serial work. Then the time t it takes the program to run in serial on one processor is the sum of the time spent in the serial portion of the code and the time spent in the parallel portion (i.e., the portion of the code that can be parallelized) is t = tg + tp. Amdahl s law defines a parallel efficiency, Pe, of the code as the ratio of total wall clock time to run on one processor to the total wall clock time to run on np processors. We give a formulation of Amdahl s law due to Meijer [42] ... 

Proper load balance is a major consideration for efficient parallel computation. Consider a job distributed over two processors (0 and 1) in such a way that wall clock time is reduced considerably. Nevertheless, it still may be that processor 0 has more work to perform so that processor 1 spends much time waiting for processor 0 to finish up a particular task. It is easy to see that, in this case, the scaling will, in general, not be linear because processor 1 is not performing an equal share of the work. 

In Fig. 4 we compare the timings for three different models, the simple one K per processor, the wrapped algorithm, and a model where two states are assigned per processor sequentially. Note that until J = 50 the one K per processor model job uses the smallest amount of wall clock time. It is clear, however, that this method does not make efficient use of computer resources. The wrapped model, however, scales very well and outperforms the sequential two K per processor model at every / > 0, a clear illustration of the degradation of performance due to load imbalance. 

Solution. Let N be the number of products and M be the number of units in the plant. Let Cj k (called completion time) be the clock time at which the jth product in the sequence leaves unit k after completion of its processing, and let tjk be the time required to process the jth product in the sequence on unit k (See Table El6.2). The first product goes into unit 1 at time zero, so Cl 0 = 0. The index j in rjk and denotes the position of a product in the sequence. Hence Cn,m is the time at which the last product leaves the last unit and is the makespan to be minimized. Next, we derive the set of constraints (Ku and Karimi, 1988 1990) that interrelate the Cjk. First, the yth product in the sequence cannot leave unit k until it is processed, and in order to be processed on unit k, it must have left unit k — 1. Therefore the clock time at which it leaves unit k (i.e., Cjk) must be equal to or after the time at which it leaves unit k — 1 plus the processing time in k. Thus the first set of constraints in the formulation is... 

Clock-time programming loads and runs a method for complete unattended operation. 

Conversion vs Clock Time for various Space Times... 

Fig. 1 Raw and smoothed data of conversion (x) versus clock time (t) for different runs showing varying degrees of catalytic activity.

Zimova et al. have determined chlorpromazine by differential pulse voltammetry in an acetonitrile medium [168]. The method involves oxidation of the derivative to the radical cation, with the reaction taking place in acetonitrile that is also 0.03M in perchloric acid. Maximum sensitivity was achieved with a scan rate of 2 mV/sec, a modulation amplitude of 50 mV, and a clock time of 40 seconds. 

Thus, apart from the constant factor c, the rate of change of concentration with position along the tube has the same form as the rate of change of concentration in time. With autocatalytic processes, for instance, this allows for a clock reaction in space rather than in time—if the reaction has an associated colour change, there can be a sharp band at a point xa related to the clock time ta by xa = ctCi. 

This category refers to loss of the usual sense of time and space. This means clock time but may also be one s personal sense of his past, present, and future. Transcendence of space means that a person loses his usual orientation as to where he is during the experience in terms of the usual three-dimensional perception of his environment. Experiences of timelessness and spacelessness may also be described as experiences of "eternity" or "infinity."... 

This implies that, in general, temporal ordering parameters cannot be identified directly with physical time—they merely share one essential characteristic. This situation is identical to that encountered in the Lagrangian formulation of general relativity there, the situation is resolved by defining the concept of particle proper time. In the present case, this is not an option because the notion of particle proper time involves the prior definition of a system of observer s clocks—so that some notion of clock time is factored into the prior assumptions on which general relativity is built. 

Mathematical derivation of the Z value equation permits the calculation of a single quantitative expression for effective time exposure at the desired temperature for sterilization. The F value measures equivalent time, not clock time, that a monitored article is exposed to the desired temperature (e.g., 121°C). F values are calculated from the following equation ... 

A rare but especially intriguing experience reported from some d-ASCs is that the direction of flow of time seems to change. An event from the future happens now the experiencer may even know it does not belong in the now but will happen later. An effect seems to precede the cause. Our immediate reaction, resulting from our deeply ingrained belief in the total reality of clock time, is that this cannot be "true," and we see the phenomenon as some confusion of time perception or possibly a hallucination. 

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