Rate homogeneous

The top-down approach involves size reduction by the application of three main types of force — compression, impact and shear. In the case of colloids, the small entities produced are subsequently kinetically stabilized against coalescence with the assistance of ingredients such as emulsifiers and stabilizers (Dickinson, 2003a). In this approach the ultimate particle size is dependent on factors such as the number of passes through the device (microfluidization), the time of emulsification (ultrasonics), the energy dissipation rate (homogenization pressure or shear-rate), the type and pore size of any membranes, the concentrations of emulsifiers and stabilizers, the dispersed phase volume fraction, the charge on the particles, and so on. To date, the top-down approach is the one that has been mainly involved in commercial scale production of nanomaterials. For example, the approach has been used to produce submicron liposomes for the delivery of ferrous sulfate, ascorbic acid, and other poorly absorbed hydrophilic compounds (Vuillemard, 1991 ... 

Turning our attention to surface phenomena rather than diffusion, we recognize that species will transit across the boundary layer and may be created or destroyed in this passage due to chemical reactions which will proceed at finite rates (homogeneous gas phase reactions). Upon impacting the surface, they may adsorb and then decompose, leaving a solid thin film. This will be a heterogeneous surface reaction which will have a characteristic chemical reaction rate. One way to describe this phenomena is in terms of a mass transfer" coefficient. The mass flux can be expressed in terms of this coefficient, as follows ... 

Rate of reaction. Factors determining reaction rate. Homogeneous reactions. Heterogeneous reactions. xplo.sion detonation rate of detonation. 

Constant product quality requires an even feed rate, homogeneous bulk density of the material to be treated, uniform densification, and reproducible maximum pressure. This statement is true for all pressure agglomeration methods. However, while these conditions can be met relatively easily in die and roller presses with proper feed preparation and specific equipment parameters, it is rather difficult to achieve in extrusion. The reason for this is that densification and maximum pressure depend on the resistance to flow in the die channel or holes. Small variations in feed homogeneity or frictional properties can yield major differences in equipment performance and product quality. Wear or buildup in the extrusion die are among the most important parameters influencing the back-pressure which, in turn, is responsible for the amount of densification prior to extrusion. 

MEASUREMENT OF GROWTH RATES HOMOGENEOUS GAS-PHASE REACTIONS... 

Measurement of Growth Rates Homogeneous Gas-Phase Reactions 290... 

The same author, in another work, used a fractional factorial design to test the influence of lipopeptides, surfactants, oil, homogenization rate, homogenization time, and pH on the mean diameter of emulsions (24). In that case, a 2- fractional factorial design was carried out. 

The kinetics of nanoparticle formation reaction, size and size distribution of the colloidal product solution depend strongly on the rate of nucleation and particle growth and the concentration dependence of both rates. Homogeneous particle sizes (narrow size distribution) are expected, if three conditions are fulfilled ... 

The theoretical methods have been previously reported and involve the computer codes ZUT and TUZ (resonance capture rates)/ THERMOS (thermal-neutron reaction rates), and MUFT (epithermal smooth reaction rates). Homogenization of the lattice was by flux-volume weighting in the fast and thermal-energy regions, and by volume weighting In the intermediate energy region. 

For constant-stretch-rate homogeneous deformation, which begins from rest, a tensile stress growth coefficient is defined as... 

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