Breaking-up of particles

The situation is quite different when moiybdenum disulphide powder is used in a liquid. As has been shown, friction reduction and film formation only arise when the geometry permits particles of the powder to be trapped between bearing surfaces, and probably sheared. Such break-up of particles within a non-polar liquid is directly comparable with the procedure used by Goszek for the production of oleophilic molybdenum disulphide, so that the resulting fractured particles will presumably also be oleophilic. 

Schutte KCJ, Portela LM, Henkes RAWM (2013) A numerical study on the formation and break-up of particle agglomerates. In Proceedings of 8th international conference on multiphase flow, Paper No. ICMF2013-731, pp 1-12... 

If a dilute acid is added to this solution, a white gelatinous precipitate of the hydrated tin(IV) oxide is obtained. It was once thought that this was an acid and several formulae were suggested. However, it now seems likely that all these are different forms of the hydrated oxide, the differences arising from differences in particle size and degree of hydration. When some varieties of the hydrated tin(IV) oxide dissolve in hydrochloric acid, this is really a breaking up of the particles to form a colloidal solution—a phenomenon known as peptisation. 

Dust The solid particulate matter formed by the breaking up of larger particulates by mechanical action. The particles range up to 75 pm in diameter larger particles are classified as grit. 

The most efficient turbulent eddies for bubble breakup are eddies of the same size as the bubbles. Large eddies will merely move the bubbles and smaller eddies do not have sufficient energy to break up the bubbles. Assuming that the most efficient eddies to break up fluid particles are eddies of the same size as the bubble, that is, A. 2d, gives the required turbulent energy dissipation... 

In the conventional method, the shard powder (or visible residue, or soil) is extracted with three separate aliquots of c. 0.5 ml DCM MeOH (dichlor-omethane methanol 1 1, v/v), with ultrasonication for 5 minutes to break up any particle aggregates and to aid dissolution. The solvent is separated from any insoluble material (including the ceramic) with centrifugation (5 minutes at lOOOrpm) and each of the three solvent aliquots is combined into a new clean vial. The solvent is then removed by placing the sample under a stream of nitrogen on a warm hotplate to aid evaporation, leaving the extracted... 

Sonication using ultrasonic cleaner baths remains a popular extraction approach particularly for controlled-release products. In sonication, an ultrasonic wave of 20-40 kHz generated by a piezoelectric transducer is used to produce the formation and collapse of thousands of microscopic bubbles (cavitations) in the water bath to facilitate the break up of the solid particles and the subsequent dissolution of the API. Note that parameters such as the wattage power of the sonicator, presence of the perforated tray, depth of the water level, bath temperature and the number of sample flasks sonicated might all affect the extraction rate. For... 

Alternative methods of assisting the fluidization of difficult materials include the use of impellers in the bed to break up agglomerated particles, particularly to help initial fluidization in plug flow driers (Reay and Baker, 1985), and the use of a pulsed gas flow (Butcher, 1988). Bahu... 

The composition of the particles larger than 0.1 ym was similar to that of the bulk ash. The fine particle composition (D < 0.1 ym) varied. Fuel lean combustion at relatively low combustor wall temperatures produced fines which contained no measure-able A1 or Si. The lack of the two major components of the coal ash supports the hypothesis that the majority of these small particles were not formed by the mechanical break-up of larger ash particles, but rather by nucleation of condensing ash vapors. 

Well, not quite everything. The hght elements lithium, beryllium, and boron are formed mostly by the break-up of heavier nuclei when hit by cosmic rays and other high-energy particles in interstellar space. This process, which whittles the nuclei down to hghter elements, is called spallation. Nucleosynthesis in stars produces very httle of these three elements. 

Newtonian fluids containing a high concentration of rigid particles can show non-Newtonian flow behaviour with increasing shear rate, due to a break up of agglomerates in the shear field [4]. For many pseudoplastic fluid suspensions the... 

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