Particle size distribution viscosity

The shiny should always be defined as completely as possible by noting suspended solids concentration, particle size distribution, viscosity, density of solids and liquid, temperature, chemical composition, and so on. 

For parenteral products specific consideration needs to be included for tonicity adjustment, emulsion globule size, ease of resuspension and sedimentation rate, particle size and particle size distribution, viscosity and syringeability, and crystal form changes. Full consideration should be included of the proposed instructions for dilution or reconstitution of products and of compatibility with the proposed solvents or diluents. This should include a demonstration that the proposed storage temperature and extremes of concentration are suitable. 

The Ph. Eur. monograph Pharmaceutical Preparations states When physico-chemical characteristics of active substances and functionality-related characteristics (FRCs) of excipients (e.g. particle-size distribution, viscosity, polymorphism) are critical in relation to their role in the manufacturing process and quality attributes of the pharmaceutical preparation, they must be identified and controlled. ... 

The physical properties that influence rheological behavior are internal phase content size, shape, and particle size distribution viscosity and rheological behavior of the continuous phase and temperature. For the case of emulsions two additional parameters, droplet deformabilhy and viscosity of the dispersed phase, should also be considered. 

Suspending of solids is the basic mixing task for any agitated crystallization process. Technical applications cover a wide range of various suspending tasks. Particle size distribution, viscosity of the solvent, and the density difference between solids and solution mainly influence the settling behavior of a suspension. The setfling rates of particles are found mostly between 0.001 and 0.1 m/s, while the soUds content of the suspension can go up to values of 50 wt% [2]. 

The RDX particle size distribution must be carefully controlled to produce castable slurries of RDX and TNT having acceptable viscosity. Several classes of RDX are produced to satisfy requirements for the various pressed and cast RDX-based compositions. A continuous process for medium-scale production of RDX has been developed by Biazzi based on the Woolwich process (79,151—154). 

Plastisol Viscosity and Viscosity Stability. After the primary contribution of the resin type in terms of its particle size and particle size distribution, for a given PVC resin, plastisol viscosity has a secondary dependence on plasticizer viscosity. The lower molecular weight and more linear esters have the lowest viscosity and hence show the lowest plastisol viscosity, ie, plastisol viscosity for a common set of other formulation ingredients... 

Of the three worldwide manufacturers of poly(ethylene oxide) resins. Union Carbide Corp. offers the broadest range of products. The primary quaUty control measure for these resins is the concentrated aqueous solution viscosity, which is related to molecular weight. Specifications for Polyox are summarized in Table 4. Additional product specifications frequendy include moisture content, particle size distribution, and residual catalyst by-product level. 

Aluminum chlorohydrate [12359-72-7] Al2(OH) Gl 2H20 is a PAG product of specific composition, having r = 2.5. Aluminum chlorohydrate is used in antiperspirants regulated by the U.S. Food and Dmg Administration (FDA). Solutions sold for FDA-approved use are colorless in appearance, have 23—24% Al as AI2O2, and low levels of iron (<50 ppm), sulfate (<0.025 %), metals (Ga, Mg, Na <10 ppm), and heavy metals (as Pb <10 ppm). The pH of these solutions at 25°G is about 3.8—4.0. Typically, solutions at 25°G have specific gravities from 1.33 to 1.35 and viscosities from 40 to 60 mPa-s(=cps). Aluminum chlorohydrate [12042-91 -0] is also available in dry form with different particle-size distributions. 

Some concerns directly related to a tomizer operation include inadequate mixing of Hquid and gas, incomplete droplet evaporation, hydrodynamic instabiHty, formation of nonuniform sprays, uneven deposition of Hquid particles on soHd surfaces, and drifting of small droplets. Other possible problems include difficulty in achieving ignition, poor combustion efficiency, and incorrect rates of evaporation, chemical reaction, solidification, or deposition. Atomizers must also provide the desired spray angle and pattern, penetration, concentration, and particle size distribution. In certain appHcations, they must handle high viscosity or non-Newtonian fluids, or provide extremely fine sprays for rapid cooling. 

Testing. The Technical Association of the Pulp and Paper Industry (TAPPl) gives test methods that are widely used by kaolin suppHers to the paper iadustry. These iaclude tests for viscosity, viscosity stabiUty, brightness, pH, particle size distribution, moisture content, and screen residue (12). 

Testing. Various test methods are provided by ASTM (16). These iaclude pigment tests of importance such as chemical analysis, presence of oversize particles, oil absorption, particle size distribution, degree of dispersion, presence of soluble components, etc. Numerous tests are also given by ASTM for the properties of filled and unfilled polymers. These iaclude, for example, such properties as impact resistance, stiffness, viscosity, tear resistance, hardness, color, and electrical resistivity. 

Although it is entirely possible for erosion-corrosion to occur in the absence of entrained particulate, it is common to find erosion-corrosion accelerated by a dilute dispersion of fine particulate matter (sand, silt, gas bubbles) entrained in the fluid. The character of the particulate, and even the fluid itself, substantially influences the effect. Eight major characteristics are influential particle shape, particle size, particle density, particle hardness, particle size distribution, angle of impact, impact velocity, and fluid viscosity. 

It is found that the viscosity of a paste made from a fixed polymer/plasticiser ratio depends to a great extent on the particle size and size distribution. In essence, in order to obtain a low-viscosity paste, the less the amount of plasticiser required to fill the voids between particles the better. Any additional plasticiser present is then available to act as a lubricant for the particles, facilitating their general mobility in suspension. Thus in general a paste polymer in which the pastes have a wide particle size distribution (but within the limit set by problems of plasticiser absorption and settling out, so that particles pack efficiently, will... 

Injection moulding compositions have a number of requirements with regard to granule flow and cure characteristics not always met by conventional formulations. For example, granules should be free-flowing (i.e. of a narrow particle size distribution and not too irregular in shape). There are also certain requirements in terms of viscosity. 

In HDPE and LDPE matrices, the introduction of PMF with polyethylene coats affects the viscosity in such a way that is independent of the nature and particle size distribution of the mineral filler employed and depends only on NMF particle size. All other conditions identical, this effect is the same as that of the particles of standard high-molecular PE [164, 297, 298]. 

Sadler, I.. Y. and Sim, K. G. Minimize Solid-Liquid Mixture Viscosity by Optimizing Particle Size Distribution, Chem. Eng. Prog, V. 87, No. 3, 1991. 

To achieve the desired cast density for Octol of 1.8g/cc it is necessary that the ratio of HMX TNT be 3 1. However, at this ratio the apparent viscosity, or efflux, is strongly dependent on the polymorphic variety of HMX used and on its particle size distribution. In the initial pilot production of Octol (Ref 3) it was found that for the desired efflux of < 15 sec, 60—70% of the solid HMX must consist of the beta-polymorph having particle diameters in the range of 500—800 microns. Such precise control of particle size was not possible at that time and early Octol casts were made at approximately 50 secs efflux. The economical production of Octol with a satisfactorily short efflux time continues to present a problem in loading shells with this expl (Refs 4, 11 29)... 

A small sample of a coal slurry containing particles with equivalent spherical diameters from 1 to 500 pm is introduced into the top of a water column 30 cm high. The particles that fall to the bottom are continuously collected and weighed to determine the particle size distribution in the slurry. If the solid SG is 1.4 and the water viscosity is 1 cP, over what time range must the data be obtained in order to collect and weigh all the particles in the sample ... 

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