Discrete physics

A discussion of reversible computation, as well as some speculations concerning the fundamental limitations of computation, have already been given in section G.4 we will not repeat that discussion here. In the remaining sections of this chapter we instead wish to focus our attention on somewhat more speculative connections between physics and computation and in what way the universe itself might be thought of as a computer. 

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A particle is a single unit of material having discrete physical boundaries which define its size, usually in micrometers, p.m (1 fim (lO" A) = 1 X cm = 1 x 10 m). The size of a particle is usually expressed by the dimension of its diameter. Typically, particle science is... 

In the preceding discussion of multispeed ac motors note that only induction motors are considered. These have no discrete physical rotor poles, so that only the stator-pole configuration need be modified to change speed. To operate multispeed, a synchronous motor would require a distinct rotor structure for each speed. Thus multispeed is practical only for squirrel-cage induction motors. 

Combination of more exnaction instfuments, that is, their successive use on the same sample, had first been applied by Gibbs [81], in the course of examination of suspended river material, and afterwards this method, with various modifications and improvements, was used by a number of authors, amongst whom probably the best known are Tessier [82, 83] and Foersmer [84-87], Very quickly the authors adopted the division into phases, which logically ensues from chemical characteristics of applicable extraction instruments, in other words, extraction instruments which meet the criteria of efficiency and selectivity to the maximum. Under phases here are implied discrete physical phases of geological material (i.e. silicate, oxide, carbonate, sulphide, organic phase, as well as fractions of heavy metals associated with them) whilst in the case of non-selectively bound metals an expression sorptive or exchangeable phase. 

Because emulsion explosives are water-in-oil emulsions, they have excellent water resistance properties. In addition, if the materials are spilled, they retain a discrete physical form and can be easily recovered and used as originally intended. By adding other constituents such as aluminum or ANFO to emulsion explosives, the detonation characteristics of the material can be substantially adjusted. Emulsion explosives are available in both sensitized and desensitized forms, which allows the blaster to select products best suited to a particular blasting operation. The relative sensitivity of emulsion products can be varied by the manufacturer and can range from DOT oxidizer 5.1, to blasting agent... 

VIABLE PARTICLE A discrete physical particle that contains one or more viable microorganisms. A viable particle may be an inert particle (dust, lint) which has one or more adherent viable microorganisms it may consist of an aggregate of two or more viable cells or it may be simply a single viable cell. Because of collection and testing limitations, most air samplings indicate a contamination level somewhere between the number of viable particles in the air and the actual number of viable microorganisms in the air. 

Conservation of Charge An excess of charge cannot be maintained in equilibrium. Conservation of charge is perhaps more difficult to grasp than conservation of energy or mass, but upon careful consideration, it is just as obvious a physical law. Since electrons and ions that carry current are discrete physical entities, the units of charge carried are also discrete. Consider the independent anodic and cathodic reactions of the fuel cell shown in Eq. (2.10) ... 

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