Milling techniques

Solid-state [4 + 2] cycloaddition of fullerene C60 with condensed aromatics using a high-speed vibration milling technique [100]... 

IAEA/AL/095 1996). Both methods were suitable, but needed to be repeated several times to produce the small particle size that was required. The particle size reduction, e.g. of IAEA-395 from a median size of 30 pm to 3.5 pm, improved the homogeneity of elements. Sampling constants (the minimum mass that can be used to achieve a random error of i % at the 65 % confidence level) improved from a factor of 1.2 for Sc, up to a factor of 800 for Au. The average improvement was about a factor of 2-10. (Ni Bangfa et al. 1996). From these initial experiences, it is dear that preparation of reference materials is critical with respect to the final particle size distribution, which should exhibit a low maximum (<50 pm) and a narrow range in particle sizes. Milling techniques to meet such criteria are available today, and materials that show intrinsic uniformity are particularly suitable to achieve the desired properties. 

Milling equipment, pilot plant, 18 732 Milling techniques, in large-scale pharmaceutical synthesis, 18 729 Millipedes, alkaloids in, 2 75 Millisecond catalytic cracking (MSCC) process, 11 685... 

Ikeda A, Hayashi K, Konishi T, Kikuchi J (2004) Solubilization and debundling of purified single-walled carbon nanotubes using solubilizing agents in an aqueous solution by high-speed vibration milling technique. Chem. Commun. 1334-1335. 

Identify a proper milling technique for the preparation of metallic and ceramic... 

While microscale devices and systems are typically fabricated from silicon, alternative materials are being examined as suitable supports. Microsystem features as small as 1 pm may be fabricated precisely by using a variety of etching, molding, and milling techniques. Since enzymatic reactions typically occur at moderate operating conditions (moderate pressures and ambient temperatures), plastics may be considered an inexpensive alternative to silicon for use as microreactor fabrication material. 

Reactive ion techniques are relatively recent and popular modifications of the traditional ion milling technique described earlier. Here, a reactive gas is... 

TABLE 8.1 Approximate Particle Size Obtainable by Various Milling Techniques... 

Dry milling techniques are more difficult to scale across sets. While the output PSD is largely a function of mill energy input (tip speed for pin mill and gas pressures... 

Waxes can increase refining losses (8). The wax content of crude oil depends on the variety of rice, milling technique, method of oil extraction, and extraction temperature (2). Extraction temperature affects both the type of wax present and its quantity (42). For example, extraction at 50° C yields two to three times more wax than extraction at 20° C. 

The goal of milling, in most cases, is to meet a size specification, which may be expressed as an acceptable range of mean particle sizes or a limit on large (typically d90 or d95) or small (d5 or dlO) particles. Even the highest energy-milling techniques will not produce a specific particle size, but instead will produce material with a distribution of particle sizes. In many cases, this distribution will be log normal, but it is not uncommon to produce multimodal distributions... 

Fig. 1 Examples of average particle sizes achieved for different milling techniques.

Mechanical grinding of drugs in the dry or wet state has been used to reduce particle size, and, if desired, crystallinity. Conventional dry milling techniques, such as micronization by air jet milling, which can produce particles with mean sizes in the unit micrometer or larger, will not be discussed in detail here. 

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