Physical Explanation

The success of periodic flow interruption is due to the liquid static holdup within the porous catalyst pellets and the interstices of the catalyst bed. 

The pattern shown in Fig. 31 is similar to that observed with BPL carbon, except that the peak reached after water is introduced and then cut off is narrow and climbs to about half of the S02 concentration in the feed. If the flush duration is 30 s, bed temperatures tend to be constant and the lowest level of S02 in the outlet occurs before water is admitted to the bed. This results in two S02 peaks within a cycle. 

With respect to periodic reversal of flow direction, this seems to be competitive for low levels of smelter gas SO2, probably under 4 vol%, at ambient temperature. If S02 is too high, thermal runaway can occur. A second, important application is to reduce S02 in the off-gas from a conventional acid plant. Use of flow reversal avoids the problem of reheating the gas leaving the first-stage absorber. 

Several uncertainties in this periodic process have not been resolved. Pressure drop is too high at SV = 10,000 h 1 when packed beds of carbon are used. Study of carbon-coated structured packing or of monoliths with activated carbon washcoats is needed to see if lower pressure drops at 95% S02 removal can be achieved. Stack gas from coal or heavy oil combustion contains parts-per-million or -per-billion quantities of toxic elements and compounds. Their removal in the periodically operated trickle bed must be examined, as well as the effect of these elements on acid quality. So far, laboratory experiments have been done to just 80°C use of acid for flushing the carbon bed should permit operation at temperatures up to 150°C. Performance of periodic flow interruption at such temperatures needs to be determined. The heat exchange requirements for the RTI-Waterloo process shown in Fig. 26 depend on the temperature of S02 scrubbing. If operation at 150°C is possible, gas leaving the trickle bed can be passed directly to the deNO, step without reheating. 

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Here it can be seen that the nucleation rate is a decreasing function of growth rate (and supersaturation). The physical explanation is believed to be the mechanical influence of the crystallizer on the growing suspension and/or the effect of Bujacian behavior. 

The Variation of J with Temperature. Although each proton transfer has its own characteristic value of 0, the variation of K near the maximum shows a marked degree of uniformity, as already mentioned in Sec. 64. If a parabola of the form p(T — 0)2 is fitted to the experimental results, a single value of p, namely 5 X 10-6, reproduces the variation of log K, not only for proton transfers of class III, but also for those of class II and class IV. If we accept (140) as providing a qualitative theory of the phenomena, we have at once a physical explanation of the observed uniformity. Whether we are concerned with the... 

W. H. E. Schwarz, Towards a Physical Explanation of the Periodic Table (PT) of Chemical Elements, in Fundamental World of Quantum Chemistry A Tribute to Per-Olov Lowdin, Vol. 3, E. Brandas, E. Kryachko (eds.), Springer, Dordrecht, pp. 645-669, 2004. Also see S.-G. Wang, W. H. E. Schwarz, Icon of Chemistry The Periodic System of Chemical Elements in the New Century, Angewandte Chemie International Edition, 2009 (in press). 

The chronology of the most remarkable contributions to combustion in the early stages of its development is as follows. In 1815, Sir Humphry Davy developed the miner s safety lamp. In 1826, Michael Faraday gave a series of lectures and wrote The Chemical History of Candle. In 1855, Robert Bunsen developed his premixed gas burner and measured flame temperatures and flame speed. Francois-Ernest Mallard and Emile Le Chatelier studied flame propagation and proposed the first flame structure theory in 1883. At the same time, the first evidence of detonation was discovered in 1879-1881 by Marcellin Berthelot and Paul Vieille this was immediately confirmed in 1881 by Mallard and Le Chatelier. In 1899-1905, David Chapman and Emile Jouguet developed the theory of deflagration and detonation and calculated the speed of detonation. In 1900, Paul Vieille provided the physical explanation of detonation... 

Comprehensive discussions on reactor stability theories and safe engineering problems were presented by Eigenberger and Schuler (1986, 1989), Zaldivar (1991), Barton and Rogers (1993), and Grewer (1994). The very basic theory developed by Semenov (1928) for zero-order reactions is very illustrative for a physical explanation of explosion phenomena. The theory enables evaluation of conditions at which thermal explosion will occur. 

At the beginning of the twenty-first century, the century of psychoanalysis may be giving way to that of brain chemistry and neuroscience. Psychotherapy is now supplemented and sometimes even replaced by antidepressants, anti-psychotics, and other pharmaceutical responses to the chemistry of the brain. Neuroscience is beginning to provide physical explanations for cognition, emotion—even subjectivity. At this border of science and our deepest sense of our mental and even spiritual selves, alchemy is again demonstrating its relevance and durability. One final realm in which alchemical tropes became (and remain) common is that of psychedelic drugs.7... 

Perturbation theory also provides the natural mathematical framework for developing chemical concepts and explanations. Because the model H(0) corresponds to a simpler physical system that is presumably well understood, we can determine how the properties of the more complex system H evolve term by term from the perturbative corrections in Eq. (1.5a), and thereby elucidate how these properties originate from the terms contained in //(pertJ. For example, Eq. (1.5c) shows that the first-order correction E11 is merely the average (quantum-mechanical expectation value) of the perturbation H(pert) in the unperturbed eigenstate 0), a highly intuitive result. Most physical explanations in quantum mechanics can be traced back to this kind of perturbative reasoning, wherein the connection is drawn from what is well understood to the specific phenomenon of interest. 

Finally, a feedback mechanism has often been used to explain observed (negative and positive) deviations from the Scatchard type plots or nonunity slopes of the nonsaturated portion of the logarithmic Michaelis-Menten plots (e.g. [209]). When no artifacts are present (cf. [197,198]), deviations can indeed be interpreted to indicate that the intrinsic stability or dissociation rate constants vary with the number of occupied transport sites. Nonetheless, several other physical explanations, including multiple carriers, non 1 1 binding, carrier aggregation, etc. must also be considered. 

The objectives of this project are consistent with the objectives (1) and (4) above. The general objective of this project has been to verify a new measurement method to analyse the thermochemical conversion of biofuels in the context of PBC, which is based on the three-step model mentioned above. The sought quantities of the method are the mass flow and stoichiometry of conversion gas, as well as air factors of conversion and combustion system. One of the specific aims of this project is to find a physical explanation why it is more difficult to obtain acceptable emissions from combustion of fuel wood than from for example wood pellets for the same conditions in a given PBC system. This project includes the following stages ... 

Organisms are completely outside the realm of physical explanation at this point for science. So what is it for Spenser and Shakespeare, quantum theory and the cave paintings at Altamira. Who are we What is history And what does it push toward Now... 

J. Prud homme, University of Montreal, Q,ue. What is the physical explanation for the leveling When we see the curve of Ti as a function of molecular weight there is a plateau. This appears at a molecular weight over 1000 and sometimes 10,000. 

Ott WR. 1990. A physical explanation of the lognormality of pollutant concentrations. J Air Waste Manag Assoc 40 1378-1383. 

This condition has a simple physical explanation. By replacing x for a in Eq. (4.15), the left-hand side is the solution inside the solid with initial value i i(0) = 1, and satisfies the continuity condition for the derivatives with respect to X at X = 0. The right-hand side of this equation simply states that at x = a, the requirement of an exponentially decaying envelope in the solid, Eq. (4.11), is satisfied. 

It is known, however, that drugs are readily available in many prisons, and the rate of adverse incidents and the time and effort spent in detecting smuggling of drugs in has been enough to persuade some authorities that at least the basics of treatment should be available. The most routine option has become to provide a detoxification for opiate misusers, with for instance lofexidine or dihydrocodeine, and also benzodiazepines will often be issued if there is a history of abuse of these and it is intended to avoid the possibility of fits with a short withdrawal course. The adverse incidents in custody and prisons have included some deaths in users of crack cocaine, with physical explanations postulated but no very satisfactory treatment for cocaine withdrawal indicated. Prison services have typically been wary of methadone, and in favouring lofexidine use it was encouraging that a randomized double-blind trial carried out by prison specialists found lofexidine to be as effective as methadone in relief of withdrawal symptoms (Howells et al. 2002). 

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