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the more sensitive expls like PETN, the influence of particle size effects on D are much less pronounced that for TNT (unpublished work by the writer and Ref 2)...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

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 ... 

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... 

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. 

Podczeck, F., Miah, Y. The influence of particle size and shape on the angle of internal friction and the flow factor of unlubricated and lubricated powders. Int. J. Pharm., 144, 1996, 187-194. 

Aromatic hydrocarbons Natural sediments Partition coefficient showing the influence of particle size [43,47,48,51,53 - 63] ... 

M. Che, and C. O. Bennett, The influence of particle size on the catalytic properties of supported... 

Chem. Geol. 157 275-284 Meisel.W. (1989) Corrosion processes and their inhibition as studied by Mdssbauer conversion and other electron spectroscopies. Hy-perfine Interactions 45 73-90 Meisen, U. Kathrein, H. (2000) The influence of particle size, shape and particle size distribution on properties of magnetites for the production of toners. J. Imag. Sci. Techn. 44 508-513... 

There is a wealth of literature on transport and kinetics in microhetero-geneous catalytic systems [175,176], the influence of particle size [177], and complicated situations in which both catalytic microparticles and electron-transfer mediators are dispersed in a polymer matrix [176-179]. The designs and uses of this type of flow-through sensors have been thoroughly reviewed [180,181]. 

The following experiment should demonstrate the influence of particle size and mini-mai fiim-formation temperature (which is connected with the glass transition temperature and therefore with the chemical structure of the polymers) on the properties of fiims, prepared from aqueous dispersions. 

Podczeck F. The influence of particle size distribution and surface roughness of carrier particles on the in vitro properties of dry powder inhalations. Aerosol Sci Technol 1999 31 (4) 301 321. 

The most important characteristics of the final formulation to be compacted are particle size and particle size distribution, density and/or porosity, powder flow, cohesiveness, and lubrication. Particle size, particle size distribution, and density and porosity of the formula will not be addressed here because they are the result of other operations in the scale-up sequence, such as granulation and milling. They should be evaluated as part of those specific operations. It should be noted, however, that the influence of particle size on powder flow and, therefore, on uniform die fill is very important to the compaction operation, but is not a result of it. The one consideration to keep in mind during scale-up is the speed of the press, which will directly affect the time available for the die filling to occur. This is an important parameter to observe carefully. 

Recently,it was reported that when maltodextrins were used as the encapsulating agent, increasing the dextrose equivalent by 10 could result in a three to six fold enhancement in shelf life (5). The reduction in emulsion size of feed emulsion also improved the shelf stability (Risch, S. J., University of Minnesota, personal communication, 1986). However, the influence of particle size distribution on the stability of encapsulated flavors has not been clearly addressed in the literature. 

O Sullivan discussed the influence of particle size on quantitative Raman monitoring in slurries [40], A system of P-form D-mannitol in toluene in the presence of sucrose was studied. It was found that although keeping the number and size of mannitol crystals constant the measured Raman signal varied with different particle size of the sucrose. These results show that particle size must always be taken into consideration in quantitative measurements and a linear relationship can not be taken for granted. 

Walker and Bodkin (1993) discuss the advantages and limitations of a number of the commonly used erosive wear testers. The influence of particle size and shape are very important as well as the impingement angle and concentration of the slurry. They found that the wear rate increases with the jet velocity to the power of 2.2 (Mens and de Gee (1986) gives 2.8-3.2.). Wear rate is at a maximum at 30° impingement angle. The mechanism is mainly cutting. The rate increases with the size of the particle. 

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