The bulk method

Like batch drying, bulk drying is performed in a tray dryer. However, the product is poured into a bulk pan and dried as a single unit. Although the product is spread throughout the surface area of the shelf and may be the same thickness as products dried in vials, the lack of empty spaces within the product mass changes the rate of heat input, which is restricted primarily to that provided by contact with the shelf 

Unlike manifold-based or batch drying, bulk drying allows no control of the conditions to which the product is exposed. Usually, the product is removed from the freeze-drying system prior to closure and then packaged in air-tight containers. Bulk drying is usually restricted to stable products scarcely vulnerable to oxygen and moisture. 

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A slight increase in oxidation state is detected by DR UV-vis spectroscopy after 1500 min. However, it was not detected when the experiment was repeated under nitrogen rather than in air. Oxygen is likely to dissolve in the solvent, oxidizing the VPO particles surface, which is not captured by the bulk method titration. 

For minerals, if diffusion is anisotropic, the bulk method gives only an average diffusivity for an assumed effective shape, but cannot determine the diffusivity along different crystallographic directions. The profiling method is necessary to quantitatively resolve the anisotropy. 

The supports themselves are usually made by the bulk methods. Examples of impregnated catalysts indude the Pd/C hydrogenation catalysts, the Pt/Sn/Al203 dehydrogenation catalysts and the automotive three-way catalysts. There are also catalysts made by hybrid synthesis approaches, e.g., where the active precursors are mixed with a powdered support, and the mixture is then agglomerated. 

The transfer system is capital- and power-intensive compared with both the traditional and bulk methods. It also requires more space and labor than does the bulk method and less than the traditional method that employs hand riddling. Mechanical riddling reduces space and labor requirements. 

Spectroelectrochemistry has become a valued technique coupling spectroscopy and electrochemistry. Spectroelectrochemistry is a bulk electrochemical technique and as such many of the cell requirements discussed above that pertain to BE apply for spectroelectrochemistry. Often concentrations for spectroelectrochemistry are much lower than most electrochemical techniques due to the spectroscopic absorbance requirements. The bulk solution must still be oxi-dized/reduced in spectroelectrochemistry. Large surface area working and auxiliary electrodes are employed as in the bulk methods described above. Cells designed with optically transparent electrodes like thin films of Sn02 or In203 or optically transparent mesh electrodes are employed, otherwise the electrode must be manually removed to record spectra. Optically transparent electrodes can be constructed such that the solution volume to electrode surface area ratio is very small making the BE occm rapidly. 

Figure 2. 2.a) Principle of the bulk method a line is first bleached through the sample (a), and then deformed by the flow. It is tilted without slip (b) or both tilted and translated with slip (c). The translation distance and the velocity profile are characterised through the deformation of the fluorescence intensity profile monitored when the distorted bleached line is translated back and passes in front of the laser beam (2.b). 

FIGURE 2.9 Averaged diapycnal mixing coefficients according to Equations 2.40 and 2.41. Vertical exchange coefficients estimated by the bulk method in the Baltic Sea (Matthaus, 1990b) at 75 m depth and Axell (1998) at 150 m depth and by dye tracer dispersion at about 300 m depth in the ocean thermocline by Ledwell et al. (1998). 

Mass selection in a heterogenous population that is undergoing inbreeding (self-pollination) is one of the oldest methods of breeding. Some breeders consider mass selection a variation of the bulk method only in the case of mass selection, the breeder... 

The first method leads to the wrapping of the CNTs with PVK [191], in other words to noncovalent functionalization. By chemical and electrochemical polymerization of VK in the presence of CNTs, the covalent functionalization of nanotubes with PVK in the undoped [33] and the doped state [194,195], respectively, is produced. Two ways have been reported for the chemical polymerization of VK in the presence of CNTs the bulk method [33] and synthesis via direct free-radical reaction [199]. 

The bulk population method of selection is amenable to small grain crops that cannot be harvested singly, which is a necessary requirement of the pedigree selection method. Selection is delayed until later generations when selection for more complex characters (eg, seed yield) is more effective. In the bulk method, a segregating population is harvested together and a sample of the seed is used to plant the next generation. For example, the F2 population is planted... 

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