Particle bimodal

The significance of this novel attempt lies in the inclusion of both the additional particle co-ordinate and in a mechanism of particle disruption by primary particle attrition in the population balance. This formulation permits prediction of secondary particle characteristics, e.g. specific surface area expressed as surface area per unit volume or mass of crystal solid (i.e. m /m or m /kg). It can also account for the formation of bimodal particle size distributions, as are observed in many precipitation processes, for which special forms of size-dependent aggregation kernels have been proposed previously. 

At low temperature flame, as-prepared titania particles had bimodal particle size. However,... 

The first process in all cases is the production of the oxidiser in a suitable fine crystal size. A bimodal particle size distribution, obtained by mixing very fine with slightly coarser particles, often gives the best product. The fuel/binder is frequently prepared as a prepolymer so as to assist mixing and also to reduce the time of the later curing process. 

By tuning /. to obtain a bimodal particle number distribution, it was possible to locate the point of coexistence between saturated thin and thick films on the adsorbing surface. The prewetting coexistence curve was then obtained through the application of this procedure at each simulation temperature. 

Example 15-1 Determine the pressure gradient (in psi/ft) required to transport a slurry at 300 gpm through a 4 in. sch 40 pipeline. The slurry contains 50% (by weight) solids (SG = 2.5) in water. The slurry contains a bimodal particle size distribution, with half the particles below 100 pm and the other half about 2000 gm. The suspension of fines is stable and constitutes a pseudohomogeneous non-Newtonian vehicle in which the larger particles are suspended. The vehicle can be described as a Bingham plastic with a limiting viscosity of 30 cP and a yield stress of 55 dyn/cm2. 

PBX-9404-03 HMX 94, NC 3 Tris(j8- chloroethyl) - phosphate 3%. The OS denotes a bimodal particle size distribution of HMX... 

ABS compositions with bimodal particle size distributions of the grafted rubber can be prepared by emulsion graft polymerization techniques. The preparation of ABS types by emulsion polymerization consists in brief of (13) ... 

Johanson, J. R. Predicting segregation of bimodal particle mixtures using the flow properties of bulk solids. Pharm Tech 46-57 (May 1996). 

In some cases, due to coalescence mechanisms (Oswald ripening), bimodal particle-size distributions are observed. 

It has been assessed that bimodal particle size distributions consisting of a population of small and large particles may exhibit a better toughening effect than unimodal ones, due to a synergistic effect (Chen and Yan,... 

In conclusion, the direct reduction is a fast process taking place between 150 and 200°C, resulting in relatively large particles with an average size of 14-16A and a bimodal particle size distribution. The desorption of NH3 and H2O at 211°C is caused by the decomposition of NH4NO3 in an independent process of the reduction. 

The equation proposed by Chong, Cristiansen and Baer [24] for the description of the rheological behavior of dispersions with a bimodal particle size distribution also includes the normalized value of the volume fraction of the disperse phase ... 

When considering a packed bed the interparticle or interstitial porosity amounts to approximately 40%. The average diameter of these interstitial voids calculates for a fairly regular packing to 0.4 times of the particle diameter, e.g. a regularly packed bed with 15 p,m particle creates interstitial pores of 6 pm. A bimodal particle size distribution of silicas employed for preparative columns can often be found, e.g. a major distribution around 15 pm and a minor peak at 4 pm. These small particles are thought to occupy the interstices between the 15 pm diameter particles and thus to stabilize the bed. 

Direct scale-up from an undeveloped laboratory procedure may result in a different product from the expected one. These differences may include smaller mean particle size, wide and/or bimodal particle size distribution (PSD), needles or plates with difficult downstream processing properties, and lack of consistent results. 

Velamakanni, B.V. and Lange, F.F., Effect of interparticle potentials and sedimentation on particle packing density of bimodal particle distributions during pressure filtration, J. Am. Ceram. Soc., 74, 166, 1991. 

The maximum packing fraction cp. can be easily calculated for monodisperse rigid spheres. For an hexagonal packing

random packing (Pp = 0.64. The maximum packing fraction increases with polydisperse suspensions for example, for a bimodal particle size distribution (with a ratio of 10 1), 0.8. 

There is a need to be able to calculate interparticle distance and other parameters from geometric models of bimodal and conventional systems. This paper explains how computer programs for the placement of spheres in a three-dimensional space have been modified to accommodate bimodal distributions. Examples of models composed of simple bimodal particle distributions are presented to illustrate the technique. 

The DGEBA/DDM/ESR phase inversion proceeds in a narrow composition range. Formation of larger particles and transitional states with bimodal particle-size distribution found in the other three formulations have not been observed for DGEBA/DDM/ESR(x). 

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