Effect of Primary Particle Size

OPS = mixing order organics-partides-salt SPO = mixing order salt-particles-organics 

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Fig. 1. Effect of primary particle size in a 1% carbon black dispersion on rate of change in reflectance. O = min = 20 min 3 = 180 min ...

Effect of Primary Particle Size on Agglomerate Growth 237... 

EFFECT OF PRIMARY PARTICLE SIZE ON AGGLOMERATE GROWTH... 

Fig. 12.7 Effect of primary particle size of MBP on bulk properties of roller compacted granules...

Primary structure sensitivity resulting from the effect of changing particle size on step and kink density appears therefore to be present here at short reaction times. Secondary structure sensitivity (including the effect of carbonaceous poisoning on the reaction rate) appears not to be present here. Thus Somorjai has reported that the dehydrogenation reaction of cyclohexane to cyclohexane is insensitive to both structural featureSt whereas the dehydrogenation of cyclohexene to benzene la very sensitive to the densities of atomic steps and kinks and the order of the carbonaceous overlayer on the platinum crystal surface. 

Fillers. Fillers for elastomers are not generally used just to fill space and cheapen the compositions. They are very important to modify the properties of rubber compositions in very positive ways. This is especially true for the so-called reinforcing fillers. Their presence in the compound can improve the strength- and durabihty-related properties of vulcanizates and can strongly enhance processing characteristics. The choice and amount of filler can have a profound effect on vulcanizate properties. These effects depend on several factors level of use (concentration), primary particle size, surface area (inverse function of primary particle size), and structure (shape factor, e.g., spherical, chain or rod-like, plate-like, and so forth). 

F. 4.12 Effect of polydispersity on the static structure factor left constant aggregation number N with log-normal distribution of primary particle size, right variation of N with p(A/ a, av) as log-normal distribution and as self-preserving distribution as obtained with DLCA processes (Eq. (4.10))... 

Small particle size extenders are the other class of opacifying aids acting as spacers, they increase the average distance between Ti02 particles in a fihn, thereby reducing crowding effects. The primary particle size of these specialized extenders is quite small (typically <0.5 pm), and the colloidal components of a coating need to be properly formulated and stabihzed in order for these materials to work effectively. 

Similar to the percolation threshold, the effective electrical conductivity of a porous Ni-YSZ cermet anode depends on the morphology, particle size, and distribution of the starting materials as well. In general, the effective conductivity increases as the NiO particle size is reduced when other parameters are kept constant. As shown in Figure 2.4 (samples 1 and 2), the cermet conductivity increased from -10 S/cm to 103 S/cm as the NiO particle size was decreased from 16 to 1.8 pm while using the same YSZ powder (primary particle size of -0.3 pm) and the same Ni to YSZ volume fraction [30],... 

The primary objective of preprocessing treatments is to remove the nonchemical biases from the spectral information. Scattering effects induced by particle size or surface roughness may lead to offsets or other more complex baseline distortions. Differences in sample density or the angle of presentation may induce overall intensity variations as well as additional baseline distortions. Most samples are not perfectly uniform on the microscopic scale, and these effects may dominate the initial contrast observed in an un-processed chemical image. In some cases this contrast may provide useful information to the analyst however, it is generally removed in order to focus on the chemical information. 

The effect of different bonding mechanisms, and of the primary particle size on granule strength, is shown in Figure 5.2. Four mechanisms (Capes, 1979 Sherrington and Oliver, 1981) need to be considered. First, intermolecular forces. The attractive force between particles is inversely... 

Spherical particles of various metal phosphate particles can be prepared by precipitation using urea as a homogeneous precipitation agent. Surface-active agents, such as SDS and CTAC, are effective in preparation of uniform-size spherical particles. The formed spherical particles are amorphous and contain OH- and H20, except cobalt phosphate particles with layered structure. These panicles are agglomerates of primary particles, and have pores of different sizes ranging from ultramicropore to mesopore. 

The sampling operation involves collection of an aerosol sample that is representative of the particle size distribution and concentration of the sampled atmosphere. The efficiency of particle transport and collection operations are dependent on the particle size, sampling velocity, the geometry of the sampling apparatus and the properties of the collection medium. In the present work, a 37 mm diameter membrane filter (0.3 ym pore size) is the primary collection medium under evaluation. The filter is housed in a standard filter cassette and effects of filter-holder inlet geometry are also being investigated. 

Filler, in general, can be defined as finely divided particles that are often used to enhance the performance and various desirable properties of the host matrix, depending on a typical application. A great deal of research endeavors have been dedicated to the development and the use of different fillers with a dimension at the nanometer level. In rubber technology the term nano is not unfamiliar to a rubber specialist. Since the start of the twentieth century, carbon black and silica have been utilized as effective reinforcing agents in various rubber formulations for a variety of applications. The primary particle sizes of these fillers remain in the nanometer range. However, with these conventional fillers the dispersion toward individual... 

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