Sedimentation methods centrifugation

Two methods are mainly used for the determination of particle size of inorganic pigments Sedimentation methods (centrifuges) and Fraunhofer diffraction with additional correction due to Mie scattering. 

Centrifugal Sedimentation Methods These methods extend sedimentation methods into the submicron size range. Sizes are calculated from a modified version of Stokes equation ... 

Another sedimentation method used is the so-called MSA-analyzer. If the value of "g" in 5.10.8. is increased (such as the use of a centrifuge) one can analyze the very smaU particles in any given distribution in a short time. The problem of course lies in accurate determination of the weight accumulated at a given time under a specific centripetal force. This problem has been neatly solved by careful design of the sedimentation tube, as shown in the following diagram ... 

Cytocentrifugation is used to prepare additional non-gynecologic specimens containing little or nonvisible sediment after centrifugation. This method is used in addition to the monolayer concentration technique for immunohisto-chemistry staining. 

Sedimentation method based on the fact that at the meniscus and at the bottom of the centrifuge cell there is never a flux of the solute across a plane perpendicular to the radial... 

WWe have seen that sedimentation by centrifugation is used for protein purification. The methods of centrifugation can be used quantitatively for the assessment of protein size and shape. 

Sedimentation. The sedimentation method, described previously 5), is based on the relative sedimentation rates of swollen and unswollen latex particles. Starting with the Stokes expression for centrifugal sedimentation, an equation can be developed for the ratio of the sedimentation coefficient of a particle, S, to the sedimentation coefficient, S, of the same particle having a surface layer ... 

The second activity is characterized by the revitalization of older instrumental methods such as gravitational and centrifugal sedimentation methods. Redesign, modernization with advanced electronics, and user-friendly, computer-aided analysis have extended the instrument product life cycle. A good example is disc centrifuge photosedimentometry (DCP), the subject of three chapters in this volume. 

The method selected depends upon the kind of material to be measured. If particles are confined to narrow limits of size, screens or microscopic methods of direct measurement may be used. When particles are distributed over a wide range of sizes we must choose indirect methods such as sedimentation or centrifuging. There is no simple method of measurement in either case, and the results are not always susceptible of interpretation unless the composition of the material is known. This will be even more evident when we consider sedimentation methods applied to particles varying widely not only in size but also in density. 

The indirect methods depend upon the use of sedimentation, elutria-tion, or centrifuging. The sedimentation method can be applied in numerous ways to the determination of average particle-diameter. These will be developed in subsequent paragraphs. So far the elutria-tion method has not been used extensively as a method of particle-size... 

Recommendations for Centrifugal Liquid Sedimentation Methods for Powders and Suspensions. 

Centrifugal sedimentation methods of particle size determination... 

Centrifugal sedimentation methods 415 8.6.4 Mass frequency undersize determination... 

BS 3406, Part 6, (1985), Determination of particle size distribution. Recommendations for centrifugal liquid sedimentation methods for particle size distribution,425... 

The hydrolysis of inorganic pyrophosphate has been carried out in cacodylate buffer, pH 5.5 [179], trichloroacetic acid was then added to terminate the reaction, denatured protein was sedimented by centrifugation, and suitable aliquots of the supernatant solution were assayed for inorganic phosphate by the method of Fiske and SubbaRow [163]. 

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