Properties of Fine Particles

Characteristics resulting from the competition between volume and surface related forces Increasing... 

Bulk density (space-filling behavior) Decreasing... 

Mixing characteristics First increasing then decreasing... 

Capillary pressure (system solid/liquid) Increasing... 

On the other hand, problems associated with mechanical processing and handling of particle systems increase with decreasing particle size. 

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FIG. 19-68 The schematic diagram showing the relationship between the physical and chemical properties of fine particles and their behavior in flotation. (G) and (R) refer to whether the phenomena affects grade and/or recovery. The arrows indicate the various factors contributing to a particular phenomena observed in flotation of fine particles (Fiierstenaii, 1980). 

Small metal particles can also be obtained by vacuum evaporation in low pressure inert gases (16). Magnetic particles of metals such as iron, cobalt, nickel, and alloys of these metals can be prepared by this method. Though the amounts of particles obtainable by this method are limited, the particles are clean as compared with particles precipitated from solutions. They are mainly used for studies of physical properties of fine particles. 

When evaluating the health effects of indoor air fine particulate matter, the indoor dynamics as well as the physical, chemical and biological properties of fine particles have to be considered. The indoor air fraction PM2.5 largely stems from outdoor air. Accordingly, the Ad-hoc AG also recommends WHO s (2006) 24-hour mean guideline value of 25 gg/m3 PM2.s for indoor air evaluation. In contrast to PM2.5, coarse particles (PMio) in schools, kindergartens and dwellings show much... 

J. L. Dormann and D. Fiorani (Eds.), Studies of Magnetic Properties of Fine Particles and their Relevance to Materials Science , Elsevier, Amsterdam 1992. 

S. Chikazumi, Physics of Ferromagnetism , Oxford University Press, (1999) or in Magnetic Properties of Fine Particles , J.L. Dorman and D. Fiorani, North-Holland 1992. 

Dormann, J.L., and Fiorani, D., Eds., Magnetic Properties of Fine Particles, North-Holland, Amsterdam, 1992. 

K, O Grady and R, W, Chantrell, Magnetic Properties of Fine Particles, chapter Magnetic Properties Theory and Experiments. Elsevier, Amsterdan, 1992... 

O Grady, K. and Chantrell, R. (1992) Magnetic Properties of Fine Particle, Elsevier, Amsterdam. 

Influence of the Interfacial Energy on the Bulk Properties of Fine Particles... 

Many of the transport properties of fine particles are comparable to those of gas ph2ise species. They migrate by convective diffusion and can remain in the air of a room for hours and even days, depending on the air exchange rate of the room. In the absence of thermophoretic forces or electric fields, they deposit with roughly equal propensity on all surface configurations and are more able to penetrate narrow spaces than coarse particles. The ratio of the surface accumulation rate (units of mass per unit area per unit time) to the airborne concentration (units of mass per unit volume) is a useful physical parameter that is commonly referred to as the deposition velocity (units of distance divided by time). The deposition velocity is the transfer... 

Shull, R.D., Swartzendruder and Bennett, L.H., Proceedings of the Sixth International Cryocoolers Conference Ed. G. Green and M. Knox, David Taylor Research Center Publ. DTRC-91/002, Annapolis, Md, p. 231, (1991) Shull, R.D., Swartzendruder and Bennett, L.H., Proceedings of the International Workshop on Studies of Magnetic Properties of Fine Particles and their Relevance to Materials Science, Rome, Italy (Nov,1991)... 

General Properties of Fine Particles Superparamagnetic Behavior B.l. Single-Domain Particles B.2. Superparamagnetic Particles... 

B. GENERAL PROPERTIES OF FINE PARTICLES SUPERPARAMAGNETIC BEHAVIOR... 

Section F.6.3 is concerned with the investigation of static properties of fine particles with focus on the differences with respect to bulk material studies. Studies of surface magnetic properties are largely developed... 

The dependence of the recoil-free fraction on particle size is complex since it can involve volume and surface effects. However, careful analyses should yield valuable information. Analyses of the / fraction can also reveal varying elastic properties of the matrix and be used to investigate dynamic effects including rheological properties of fine-particle systems. 

Neutron experiments lead to very reach features concerning particularly the dynamical properties of fine particles. However, at present, only one particle kind has been studied by inelastic neutron scattering and the studies of other particle types, other morphologies, would be interesting for the establishment of general behaviors. On the other hand, theoretical development would also be useful for the analysis of the data as well as the understanding of outcomes. 

In this chapter, we have tried to carry out the restatement of the magnetic properties of fine particles resulting from the relaxation of their magnetic moments from theoretical as well as experimental points of view. We discussed the models, several with some details, that allow one to calculate the relaxation time of the particle magnetic moment, to evaluate the effect of the interparticle interactions, and to interpret the experimental results. We clearly stated our objections, without use of indirect sentences understandable only by specialists, because fine-particle studies can be of interest in various fields, for example, catalysis, biology, mineralogy. Of course, this is our opinion at the present time. 

Material properties of fine particles change according to the dimensions on an atomic scale and in the bulk region. In the case of Au fine particles, the melting temperature drops abruptly with a diameter less than 5 nm, which was studied by a high-energy electron diffraction technique [10]. The... 

Sundar, Manoharan, S. (1991) Combustion synthesis and properties of fine particle spinel, perovskite and K2Nip4 type oxides. Ph.D Thesis, Indian Institnte of Science, Bangalore. 

Arul Dhas, N. and Patil, K.C. (1993) Combustion synthesis and properties of fine particle spinel manganites./owrmi/ of Solid State Chemistry, 102, 440-445. 

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