Influence of particle size

For the more sensitive expls like PETN, the influence of particle size effects on D are much less pronounced that for TNT (unpublished work by the writer and Ref 2)... 

Hulbert [77] points out that, in general, attempts to include an allowance for the influence of particle size variations in the reactant mixtures on kinetic analyses using the above equations have been unsatisfactory because some of the parameters are not readily defined. Kapur [42], working with powders of known crystal size distribution, indicated that the overall extent of reaction can be estimated by a summation of the individual contributions from each size fraction and thus the best kinetic fit determined. 

INFLUENCE OF PARTICLE SIZE DISTRIBUTION ON KINETIC CHARACTERISTICS... 

With the following example, we illustrate how in a sequence of activities the students intuitive notions about the influence of particle size and the sintering temperature of the clay on the properties of ceramic materials have productively been used (Klaassen Lijnse, 1996 Mortimer Scott, 2003 Duit Treagust, 2003 ... 

Influence of Particle Size on Reaction Activity and Selectivity... 

INFLUENCE OF PARTICLE SIZE ON ELECTROCATAI YTIC ACTIVITIES CASE STUDIES... 

An influence of particle size on the kinetics of COads electro-oxidation has been shown by Maillard and co-workers with FTIR spectroscopy. It has been suggested that the reaction starts on the terraces of large (> 3 nm) particles, and then propagates to the particle edges. Electro-oxidation of COads on small (<2nm) particles commences at more positive potentials, when COads on large particles is oxidized. 

CO2 increased from 50% to 80%. It would be highly desirable to investigate MOR on model nonporous substrates with DBMS in order to determine the influence of particle size on various reaction steps and the partitioning between the direct and indirect pathways. 

As the reader might have noticed, many conclusions in electrocatalysis are based on results obtained with electrochemical techniques. In situ characterization of nanoparticles with imaging and spectroscopic methods, which is performed in a number of laboratories, is invaluable for the understanding of PSEs. Identification of the types of adsorption sites on supported metal nanoparticles, as well as determination of the influence of particle size on the adsorption isotherms for oxygen, hydrogen, and anions, are required for further understanding of the fundamentals of electrocatalysis. 

Most lung deposition models are based on the influence of particle size on aerosol deposition. Breathing parameters, such as breathing frequency and tidal volume, play a key role in lung deposition [15]. Table 2 shows the breathing parameters for healthy male volunteers subjected to various levels of exercise on a bicycle ergometer [16], There are known differences in these parameters based on gender, age, and disease... 

M Kraml, J Dubuc, R Gaudry. Gastrointestinal absorption of griseofulvin II. Influence of particle size in man. Antibiot Chemother 12 239-242, 1962. 

The outcome of the experiments on nickel and on iridium shows that there is a marked contrast between these metals as regards the influence of particle size upon the course of the reaction of benzene with deuterium. Clearly, further experiments should be done along the same lines with other metals of group VIII of the periodic system. 

Ackeskog et al. (1993) made the first heat transfer measurements in a scale model of a pressurized bubbling bed combustor. These results shed light on the influence of particle size, density and pressure levels on the fundamental mechanism of heat transfer, e.g., the increased importance of the gas convective component with increased pressure. 

Guardiola, J., Rojo, V., and Ramos, G., Influence of particle size, fluidization velocity, and relative humidity on fluidized bed electrostatics, J. Electrostatics, 37 1-20 (1996)... 

The activity in terms of 1st order rate constant khcalc was calculated in Table 2 from (8) and (9) with effective diffusivity Dejf=5.3-10 6 m2/s and intrinsic rate constant =33000 Nm3/h/m3 = 23 s"1 fitted to the measurements. This simple and useful method models the measured influence of particle size satisfactorily for a first optimization of particle size and shape. The 35% higher activity measured for the 9-mm Daisy compared to the 12-mm Daisy, however, exceeds the 25% expected from (8), and this illustrates the importance of measuring the activity of the actual shape. 

Kaneniwa N, Watari N. Dissolution of slightly soluble drugs. I. Influence of particle size on dissolution behaviour. Chem Pharm Bull 1974 22(8) 1699-1705. 

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