Erosion characteristics

The cyclones are typically designed with diameters of 100—160 cm for ease of maintenance. Cyclone inlet velocities are usually restricted to 18—21 m /s in the first stage and to 20—26 m/s in the second stage to achieve satisfactory pressure drop and erosion characteristics (62). The number of sets of two-stage cyclones thus depends on the total gas flow. Finding room to house all the necessary cyclones within the regenerator frequently requires considerable ingenuity (62). 

In support of the power recovery expander market for fluid catalytic cracking units in refineries, some turboexpander manufacturers have an ongoing program to improve the solid particle erosion characteristics of the machine. Improved erosion characteristics will result in longer blade life, less downtime, and consequently greater profits for the users. 

In this paper, then, the previously developed model (7) is extended to the calculation of erosion characteristics of a well described polymeric delivery system, the acid-catalyzed erosion of poly (ortho ester)s (2-6). This system is chosen as the example system because of the completeness of the data package in the open literature. It is expected that this modelling approach is also useful for other hydrolytically unstable polymeric drug delivery systems. 

For poly (ortho ester)s, the amount of catalyst present can drastically alter the erosion characteristics. As a result, consider the results of the mathematical model at two different anhydride levels, 0.25% and 1.0%. 

A mathematical model has been developed which allows the calculation of the degradation of polymeric drug delivery systems. The model has been shown to accurately simulate both the drug release and molecular weight changes in such systems. The concentration of anhydride levels affect the erosion characteristics of... 

Pharmaceutical research has to date been focused on polyanhydrides derived from sebacic acid (SA) and its copolymers with bis(p-carboxyphenoxy)propane (CPP) [75,113,115,119]. More recently, a new class of polyanhydrides was presented, containing fatty acid dimers (FAD) [ 116,118,258]. Erosion characteristics, microsphere preparation, pH-dependence, release rates, morphology, and in vivo performance of polyanhydrides from SA, CPP, and FAD have been intensely studied [75, 111-115,117, 119, 258-260]. Other unsaturated polyanhydrides have been derived from ricinoleic acid [261] and ricinoleic acid half-es-... 

One candidate polymer system is the poly(ortho esters), which are pH-sensitive and undergo enhanced hydrolysis rates with decreasing external pH values (6). Furthermore, this system has demonstrated surface erosion characteristics and can be prepared in both linear and crosslinked forms (7., 8). The crosslinked form is particularly interesting because sensitive macromolecules can be incorporated into the polymer under very mild conditions and without denaturation. These mild conditions are important because both insulin and glucose oxidase are proteins. 

Nguyen TH, Higuchi T, Himmelstein J. Erosion characteristics of catalyzed poly(orthoester) matrices. J Controlled Release 1987 5 1-12. 

Recent work has shown that quartz particles above a certain particle size are very influential in the erosion process and that furnace temperature history plays an important role in determining erosive characteristics of the particles (3,4). 

S. Biswas, and A. Satapathy, A comparative study on erosion characteristics of red mud filled bamboo-epoxy and glass-epoxy composites. Mater. Des. 31, 1752-1767 (2010). 

Akbari, H., D Emanuele, A., Attwood, D., 1998. Effect of geometry on the erosion characteristics of polyanhydride matrices. International Journal of Pharmaceutics 160, 83—89. 

There are four parts of output data firstly, during the calculation the datum of calculation were saved every five minutes for convenient comparison of erosion characteristic at different time secondly, measure circles (Figure 4) were set to monitor porosity change of soil mass at different position thirdly, position change of eight particles in section y = 0.024 m were monitored lastly, flow rate of fluid in different cells (Figure 5) were monitored. 

Corrosion-erosion characteristics of material removal in metal CMP... 

Water velocity and turbulence can damage protective films and deposits on metal surfaces causing increased corrosion. Soft metals, such as copper, are particularly susceptible to erosion corrosion, but steel and other metals are also susceptible if the water velocity is sufficiently high. The critical velocity for erosion-corrosion of copper in freshwater is about 5 s (1.52 m/s), but this velocity can drop sharply as the chemical corrosivity of the water increases. Suspended solids in the water can increase the erosion characteristics of the water [1]. Deposits can result in accelerated corrosion from the formation of oxygen differential concentration corrosion cells. 

Standard test method far cavitation erosion characteristics of aluminium pumps with engine coolants... 

Thorium oxide. The major portion of studies on corrosion-erosion characteristics of high-temperature aqueous slurries has been carried out using thorium oxide [110-111]. Most preparations have used the calcination product of thorium oxalate precipitated under various conditions, with calcination temperatures from 450 to 1600°C having been used. Thoria prepared by other procedures, such as formate precipitation, has also beeti examined. Thoria calcined at temperatures in the vicinity of 1600°C has low surface area, crystallite sizes approaching particle size, less tendency to degrade, and exhibits a greater tendency to produce abrasive sintered particles consequently, certain of such thoria products have been... 

Morino, Y., Yoshinaka, T., Auweter-Kurtz, M. (2002). Erosion characteristics of SiC coated C/C materials in arc-heated high enthalpy air flow. Acta Astronautica, 50(3), 149-158. doi 10.1016/80094-5765(01)00150-3. 

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