Excursions

The subsequent representations are probably reliable within the range of data used (always less broad than 200° to 600°K), but they are only approximations outside that range. The functions are, however, always monotonic in temperature, to provide appropriate corrections when iterative programs choose temperature excursions outside the range of data. 

Short-term exposure. This is the maximum concentration to which workers can be exposed for a period of up to 15 minutes continuously without suffering from (a) intolerable irritation, (b) chronic or irreversible tissue change, or (c) narcosis of sufficient degree to increase accident proneness, impair self-rescue, or materially reduce efficiency, provided that no more than four excursions per day are permitted, with at least 60 minutes between exposure periods, and provided the daily time-weighted value is not exceeded. 

Excitable media are some of tire most commonly observed reaction-diffusion systems in nature. An excitable system possesses a stable fixed point which responds to perturbations in a characteristic way small perturbations return quickly to tire fixed point, while larger perturbations tliat exceed a certain tlireshold value make a long excursion in concentration phase space before tire system returns to tire stable state. In many physical systems tliis behaviour is captured by tire dynamics of two concentration fields, a fast activator variable u witli cubic nullcline and a slow inhibitor variable u witli linear nullcline [31]. The FitzHugh-Nagumo equation [34], derived as a simple model for nerve impulse propagation but which can also apply to a chemical reaction scheme [35], is one of tire best known equations witli such activator-inlribitor kinetics ... 

Sci. 1989, 29(3), 227-228. p5] O. Ivanciuc, Coding the constitution -Graph Theory in chemistry, in Handbook of Chemoinfbrmatics, J. Gasteiger (Ed.), Wiley-VCH, Weinheim, 2003, Chapter II, Section 4. pq L. Euler, Soluho Problematis ad Geo-metriam Situs Pertinentis, Commen-tarii Academiae Sdentiarum Imperia-lis Petropolitanae 8,1736, pp. 128-140. p7] A. Beck, M. Bleicher, D. Crowe, Excursion into Mathematics, Worth, 1969. 

If the spring follows Hooke s law, the force it exerts on the mass is directly proportional and opposite to the excursion of the particle away from its equilibrium point Xe- The particle of mass m is accelerated by the force F = —kx of the spring. By Newton s second law, F = ma, where a is the acceleration of the mass... 

It is a property of this family of differential equations that the sum or difference of two solutions is a solution and that a constant (including the constant i = / ) times a solution is also a solution. This accounts for the acceptability of forms like A (t) = Acoscot, where the constant A is an amplitude factor governing the maximum excursion of the mass away from its equilibrium position. The exponential form comes from Euler s equation... 

Under what circumstances would the maximum speed be numerically equal to the maximum excursion for a simple hamionic oscillator ... 

Suppose that we agree to regard the N—N molecule as a classical (nonquantum) haiinonic oscillator and we stipulate that each N atom makes a maximum excursion away from its equilibrium bond length of 0.006 A during each vibration. 

What is the minimum atomic speed Where in their excursion do the atoms reach their minimum speed ... 

Where in their excursion is the maximum atomic speed attained ... 

Interference effects, which arise because of the extraordinary uniformity of thickness of the film over the spectrometer sample beam, superimposed on the absorption of incident light by parylene films, can be observed. Experimentally, a sinusoidal undulation of the baseline of the spectmm is seen, particularly in the spectral regions where there is Htde absorption by the sample. These so-called "interference fringe" excursions can amount to some... 

The first experimental breeder reactor (EBR-1), which was the first reactor to generate electricity on a practical basis, went into operation in 1951 at the National Reactor Testing Station in Idaho. After the first reactor was damaged by a power excursion, EBR-11 was put into operation in 1961 (57). As of early 1995 it continued to operate very well. 

The homogeneous reactor experiment-2 (HRE-2) was tested as a power-breeder in the late 1950s. The core contained highly enriched uranyl sulfate in heavy water and the reflector contained a slurry of thorium oxide [1314-20-1J, Th02, in D2O. The reactor thus produced fissile uranium-233 by absorption of neutrons in thorium-232 [7440-29-1J, the essentially stable single isotope of thorium. Local deposits of uranium caused reactivity excursions and intense sources of heat that melted holes in the container (18), and the project was terrninated. 

The accident at the Three Mile Island (TMI) plant in Pennsylvania in 1979 led to many safety and environmental improvements (4—6). No harm from radiation resulted to TMI workers, to the pubHc, or to the environment (7,8), although the accident caused the loss of a 2 x 10 investment. The accident at the Chernobyl plant in the Ukraine in 1986, on the other hand, caused the deaths of 31 workers from high doses of radiation, increased the chance of cancer later in life for thousands of people, and led to radioactive contamination of large areas. This latter accident was unique to Soviet-sponsored nuclear power. The Soviet-designed Chemobyl-type reactors did not have the intrinsic protection against a mnaway power excursion that is requited in the test of the world, not was there a containment building (9—11). 

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