Processing aggregation

The formation of the planets around the proto-sun initially started as a simple accretion process, aggregating small particles to form larger particles. This process was common to all planets, even the gas giants Jupiter and Saturn and to a lesser extent Neptune and Uranus. The planetesimals form at different rates and as soon as Jupiter and Saturn had reached a critical mass they were able to trap large amounts of hydrogen and helium from the solar nebula. The centres of Jupiter... 

Larger particles of grit and dust settle relatively fast, but colloidal solids can require weeks for complete sedimentation (i.e. colloid breaking) to occur completely. Such sedimentation occurs when microscopic colloid particles approach, touch and stay together because of an attractive interaction, and thereby form larger particles, and sink under the influence of gravity. We call this process aggregation. 

SCHEME 1. The dynamic behavior of organozinc compounds involves C—Zn exchange and C—Zn bond inversion as main processes. Aggregation and ligand exchange dynamics complete the overall picmre describing the dynamics of these compounds... 

Bacteria are invading cells which are not growing and are degrading cellular material, which is being solubilized. During this process aggregation often take place and cells will finally die [74]. 

In addition, the general structure of the resulting assessment matrix is reported in Table 8.6 the columns represent the textile and clothing processes (divided into primary processes, support processes and mechanical plants) the rows represent the environmental impacts (KPIs) and each cell reports the significance of the specific environmental impact for the specific process. Aggregate ratings are also possible. 

Apart from nucleation and crystal growth, aggregation is an important process. Aggregation leads to fewer and larger, but yet porous particles. 

A third approach to quantifying health hazard risk is one in which incremental changes in an exposure biomarker, like blood lead, is linked to incremental changes in some health metric, e.g., reduction in IQ. In this process, aggregated empirical data for both the lead exposure metric and the health harm metric are employed to generate a numerical slope relationship. The most quantitative use of this approach meta-analytically has been that of Lanphear et al. (2005) for longitudinally derived epidemiological relationships of elevated PbB to IQ decrements in preschool or elementary school children described in international studies. 

Agglomeration simultaneous aggregation and surface growth In many processes aggregation and surface growth occur at the same time. This is encountered in precipitations of some inorganic salts, and also in polymerization processes where polymers are precipitated. The salts are usually crystalline, and... 

In terms of processability, aggregation of asphaltenes can hinder the conversion of heavy residues to lighter products and can enhance coke formation. Using smface tension measurements and rheological data, Sheu et al. and Storm et al. have shown that asphaltenes exhibit properties similar to colloids. These colloids exist in the heavy oil matrix in a micelle form. Since the mole fraction of resins is higher than asphaltenes in petroleum, micelles are richer in resins. Asphaltenes also exhibit properties of colloidal systems such as the critical micelle concentration (CMC) at which aggregates begin to form. 

W/o microemulsion solutions are mostly transparent, isotropic liquid media with nanosized water droplets that are dispersed in the continuous oil phase and stabilized by surfactant molecules at the water/oil interface. These surfactant-covered water pools offer a unique microenvironment for the formation of nanoparticles. They not only act as microreactors for processing reactions but also exhibit the process aggregation of particles because the surfactants could adsorb on the particle surface when the particle size approaches to that of the water pool. As a result, the particles obtained in such a medium are generally very fine [76]. Inverse microemulsion droplets, however, are slightly polydisperse due to less strict transformation of... 

According to this model creep is a manifestation of aging, i.e., the material moves towards a lower total energy by aggregation of sheets due to ihe formation of more layers. Surface area is reduced by this process. Aggregation is accelerated by stress and facilitated by the presence of interlayer water. 

Various mechanisms have been proposed for the attachment of cells to an inactive support, such as glass or plastic (adhesion) to themselves before or after a degradative process (aggregation) to antibodies, other... 

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