Evaluation of the experimental results

The experimentally found time-related changes in the biochemical content of particles are similar to those observed in the Pacific Ocean from the surface to deep waters. The amount of stable OM in the particles increases with depth (Agatova and Bogdanov, 1972). 

Thus the degree of OM decomposition, amounting to 70—80% of the initial amount (at 20°C) in the long-term experiment, is close to that in wata bodies containing hydrogen sulphides it is evidently lower for the oxygen-containing ones. 

As it was estimated by Kuznetsov (1970), for a water layer of 12 m thickness in Lake Beloye (Kosino, U.S.S.R.), 90% of the OM from the annually produced phytoplankton is degraded. The same value was suggested for the Rybinsk reservoir, U.S.S.R. (Kuzin, 1972). Studies carried out by Ohle (1962), for three Holstein lakes, showed that the annually produced OM was mineralised to extents of 86, 89 and 96%. 

The dissolved organic components studied in the aerobic experiment decreased more rapidly than the particulate ones (Bikbulatova et al., 1977). Only the carbohydrates (their content usually correlated with that of dissolved organic C) were also present at the end of the experiment, evidently being part of stable OM complexes. It is clear that in the natural environment, especially during vegetation time, the dissolved labile oi anic compounds are constantly replenished as a result of the activity of hydrobionts. 

A number of well-known organic compounds (labile among them) have been shown to be present in ocean waters. They belong to various classes 

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The mass transfer model. In our previous work [6] the mass transfer model equations and their mathematical treatment have been described extensively. The relevant differential equations, describing the process of liquid-phase diffusion and simultaneous reactions of the species according to the penetration theory, are summarized in table 1. Recently we derived from this penetration theory description a film model version, which is incorporated in the evaluation of the experimental results. Details on the film model version are given elsewhere [5]. 

Recently, a new microelectrochemical technique applying microcapillaries as electrochemical cells has been developed. Only small surface areas, a few micrometers or even nanometers in diameter, are exposed to the electrolyte. This leads to current resolution, down to picoamperes. Microelectrochemical techniques, combined with statistical evaluation of the experimental results may give greater insight into the mechanism of these processes.27... 

The evaluation of the experimental results plus consideration of H, CO2, and Ca fluxes indicate that it is energetically much more efficient to initiate calcite precipitation by removal of protons, rather than ions (Zeebe Sanyal... 

The dependence of the Si -spin dynamics on the S2 chemical shielding tensor will in general increase the number of spin parameters, which have to be known or determined for a meaningful evaluation of the experimental results. This is certainly a disadvantage when the only goal is extraction of dipolar coupling information. But even for cases where it is feasible to extract all dipolar and... 

The clear evaluation of the experimental results is also hindered by the difficulties encountered in the perfect purification of non-aqueous solvents. Several of them are hygroscopic, and even an extremely low water content may cause fundamental changes in the chemical properties of numerous solvents. As an electron-pair donor, the water molecule may behave as a ligand, and as a consequence of the ability of its hydrogen atoms to form hydrogen bonds, it may also act as an acceptor. This may lead to the occurrence of unexpected side reactions. In acidic solvents water behaves as a base, and in basic solvents as an acid, thereby disturbing the courses of the reactions to be investigated. The removal of trace amounts of water and the performance of work under anhydrous conditions is a difficult task. 

The physiological tests also are not very reliable. Firstly, the extrapolation of animal experiments to humans is doubtful the species need to be selected carefully. The hygienic conditions are crucially important. And the correct evaluation of the experimental results requires that, as well as the rate of mortality, the direct reasons of death should be determined, which is quite expensive and involves highly qualified personnel. 

Figure 3.7. The longitudinal Bodenstein number of the total pulse function, BOtot for the liquid phase of a tube-type reactor with recycling as a function of the recycle ratio, r. The evaluation of the experimental results are compared with the theoretical calculation, Equ. 3.15b. (From Moser and Steiner, 1974 and 1975).

In the evaluation of the experimental results the distribution of concentration and temperature appear... 

An evaluation of the experimental results of this work has shown that this equation is applicable to a Wep/Frp number range of around 28.8 to 1300. Based on the results on the liquid hold-up, it can be concluded that by modifying the models known from literature [12, 19, 44], the total liquid hold-up below the loading line can be determined with... 

The evaluation of the deconvolution results show that time resolution is better or equal to 1 with the chosen processing time unit of 0.08 microseconds (respectively a rate of 12.5 MHz). First signals processed conservatively have been acquired with a samplerate of 12.5 MHz. A Fourier analysis shows that the signals spectras do not have energy above 2.0 MHz. This means that a sampling rate of 4.0 MHz would have done the job as well. Due to the time base of the ADC an experimental check with a sample rate of 5.25 MHz has been carried out successfully. 

Design of experiments. When conclusions are to be drawn or decisions made on the basis of experimental evidence, statistical techniques are most useful when experimental data are subject to errors. The design of experiments may then often be carried out in such a fashion as to avoid some of the sources of experimental error and make the necessary allowances for that portion which is unavoidable. Second, the results can be presented in terms of probability statements which express the reliabihty of the results. Third, a statistical approach frequently forces a more thorough evaluation of the experimental aims and leads to a more definitive experiment than would otherwise have been performed. 

Very recently, considerable effort has been devoted to the simulation of the oscillatory behavior which has been observed experimentally in various surface reactions. So far, the most studied reaction is the catalytic oxidation of carbon monoxide, where it is well known that oscillations are coupled to reversible reconstructions of the surface via structure-sensitive sticking coefficients of the reactants. A careful evaluation of the simulation results is necessary in order to ensure that oscillations remain in the thermodynamic limit. The roles of surface diffusion of the reactants versus direct adsorption from the gas phase, at the onset of selforganization and synchronized behavior, is a topic which merits further investigation. 

The flash desorption technique is applied usually in ultrahigh vacuum conditions. Then all the mentioned contributions to S and F should be accounted for in the evaluation of the experimental desorption curves. The effect of Sw on the results of desorption measurements is discussed in... 

The following considerations must be taken into account in the evaluation of any experimental results ... 

Are the equilibrium constants for the important reactions in the thermodynamic dataset sufficiently accurate The collection of thermodynamic data is subject to error in the experiment, chemical analysis, and interpretation of the experimental results. Error margins, however, are seldom reported and never seem to appear in data compilations. Compiled data, furthermore, have generally been extrapolated from the temperature of measurement to that of interest (e.g., Helgeson, 1969). The stabilities of many aqueous species have been determined only at room temperature, for example, and mineral solubilities many times are measured at high temperatures where reactions approach equilibrium most rapidly. Evaluating the stabilities and sometimes even the stoichiometries of complex species is especially difficult and prone to inaccuracy. 

Heterocyclic chemistry offers a much wider prospect for exploring the possibilities and limitations of the aromaticity concept than hydrocarbon chemistry. As a result, quantitative measures for aromaticity have been devised, and improved molecular calculation methods allow for a better evaluation of the experimental data already obtained and predictions of novel aromatic heterocycles. 

Another method used to vary the AG° of the recombination reaction without chemical modification of the centers, consists of placing the system in an electric field whose orientation and intensity are well defined [141]. However, the energy level shifts induced by the field also change the electronic factors, so that the interpretation of the experimental results is not straightforward. Bixon and Jortner have proposed using electric field effects to elucidate the nature of the primary electron step in bacterial photosystems [142], a problem that will be discussed in Sect. 3.5. One basic difficulty encountered in this method is the evaluation of the internal field effectively seen by the redox centers in the membrane. 

In the following discussion of some earlier work in the field of adsorption in the light of the experimental results and concepts in this article, we shall attempt to evaluate how much of the results can still be relied upon and what results should be reexamined with modern tools and techniques. 

The energy difference AF between gauche and trans conformers, resulting from rotation about single bonds of the chain backbone in trans-1,4-polybutadiene, c/s-1,4-polybutadiene and 1,5-hexadiene, is evaluated from IR measurements on the bands characteristic of bending vibration of CH2 groups. Consideration of the experimental results, on the basis of the RIS model, leads to the conclusion that a value of 0.4 to 0.8 kJ mol-1 is the best estimate of AF. 

It was possible to restrict the mathematical evaluation to the experimental results to determine the influence of alkalinity and temperature. For calculation purposes the changes in the reaction, obtained by varying the Si02 source or by adding potassium ions do not differ substantially from those obtained by varying the NaOH concentration. 

The study of several polyelectrolytes through various experimental methods has led to diverging results and controversial conclusions. This situation has recently been summarized from the theoretical point of view in [28,95-97]. However, there are some interesting data resulting from experiments with PDADMAC and DADMAC copolymers which remain unexplained. The aim of this Section is to present these experimental results and, furthermore, to discuss the data in terms of existing polyelectrolyte theories. For a better understanding of the experimental results under discussion a short fundamental summary of the main properties and parameters shall be given. However, it is not the aim of this review to evaluate the various theoretical approaches. 

Clearly, the successful reproduction of the experimental result is, in part, related to the high quality of the potential energy surface. A more direct evaluation of the accuracy of transition-state theory can be obtained via a comparison to other (more exact) theoretical approaches to the calculation of the rate constant, all using the same potential energy surface. Table 6.3 shows such a comparison. We observe that transition-state theory does overestimate the rate constant but the agreement is quite reasonable, especially when the simplicity of the calculation is taken into account. 

Assisting in the evaluation and interpretation of results to ensure that the data are analytically acceptable and correctly correlated to tell the story of the experimental results. 

M/1, and it is therefore expected that in that condition different hydroxide species are predominant (cf. Figure lb). In pH > 8 vi/here [COp] > 10 M/1, the formation of hydroxocarbonate and carbonate complexes may take place. For this reason, evaluation of the final results is mainly based on the experimental data from the solutions of pH > 8 and [C07 J > 10 M/1. 

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