Classifier Machinery

A common problem in both chemical and metallurgical practice is that of separating relatively coarse particles, which are called sands, from a slurry of fine particles, which are called slimes. The most common method is to use continuous settling equipment called classifiers. 

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Rotor blades also form an element of several external classifiers that are used in closed-circuit dry milhng. These are generally called mechanical air separators or classifiers. Examples are the Whirlwind classifier Sturtevant Inc.), the Gayco centrifugal separator Universal Road Machinery Co. (see Fig. 20-41), and the whizzer separator Raymond Division of Combustion Engineering Inc.). 

As representative examples of the various machineries used for classification mention may be made of mechanical classifiers, hydraulic classifiers, and hydrocyclones. Simplified sketches of these have been shown in Figure 2.12 (A-C). 

Nuclear receptors exert their different transcriptional functions through interactions with and the recruitment of co-factors to responsive promoters. Co-factors are either positive or negative regulatory proteins and are classified as co-activators, which promote, or co-repressors, which attenuate the activity of nuclear hormone receptors [46]. The molecular mechanisms that regulate the mutually exclusive interactions of the nuclear receptor with either class of co-factors have been analysed by crystallographic studies. Functional and structural studies have shown that co-activators interact with the transactivation function (AF) of nuclear hormone receptors via short, leucine-rich motifs (LXXLL) termed NR boxes , thereby transducing hormonal signals to the basal transcription machinery [47]. 

The cytoplasm is the semi-fluid polyphasic colloid that comprises the bulk of the cell s interior between the cell membrane and the nucleus it contains enzymes responsible for catalyzing the biosynthetic machinery of the cell and organelles responsible for specific tasks within the cell. Cytoplasm must be differentiated from protoplasm protoplasm is the whole material contained within the cell membrane and is further differentiated into the material found within the nucleus (nucleoplasm) and material external to the nucleus (cytoplasm). Organelles are important functional structures within the cytoplasm. Various structures visible by light microscopy are classified as organelles, including mitochondria, endoplasmic reticulum, and lysosomes. 

The process engineering tasks are classified according to the product groups for which they are used. There are four main areas material mixing, material separation, reaction, and phase transformation. The common factor of all the processes in Table 2.1 is of course the high-viscosity phase and consequendy the specific difficulties of the machinery (technical design, dimensioning with respect to forces, torques, drive power, pressures). 

Instead of including all assets in a single depreciation account, it is possible to classify properties into general types, such as machinery and equipment, office furniture and fixtures, buildings, and transportation equipment. The records for these groups are known as classified accounts. A classified account is similar to a composite account because many items are included in the same group, regardless of life characteristics. 

It would be impossible to list all uses of iron and steel products. In general, those products can be classified into categories (1) automotive (2) construction (3) containers, packaging, and shipping (4) machinery and industrial equipment (5) rail transportation (6) oil and gas industries (7) electrical equipment and (8) appliances and utensils. 

At the present time abstracts in the field of fabrication methods and equipment for plastics are not a very important source of information. No formal abstracting service in this field is known to the authors, although possibly some abstracts cover fabricating methods and equipment when such information appears in other classifications of literature. Chemical Abstracts deals mainly with the chemical nature of the materials being fabricated and not with the fabrication processes and machinery. It does not appear likely that an abstract service would be able to pay its own way because of the relatively few engineers who are engaged in development of fabrication methods and equipment for plastics. Some of the trade magazines do abstract each others articles as well as recently received manufacturers technical data bulletins. This information is not usually classified nor is it selected by any systematic method. 

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