Sieves screen design

There is a class of experimental designs, called screening designs, that can be used to sieve factors. Behind almost all of these designs is an implicit linear model that is first-order in each factor. The model is... 

Table 4. Variables and experimental domain in the D-optimal screening design of enamine synthesis over molecular sieves...

The material on solids was abstracted in part from Gilson Co. literature by permission. Sieves for most laboratoiy work are round and vary from 3 to 12 inches in diameter. They are made of brass to be less static and magnetic. The screen itself is either woven wire, electroformed metal, woven cloth, or machined plastic. Each sieve is designated by its mesh. Mesh is the number of holes per linear inch of screen. A 10 mesh screen would contain 10 holes along 1 inch. Caution A 10 mesh screen has 1 Ox 10 or 100 holes per in not just 10 holes as you might suspect. 

The sieve is made of a wire mesh cloth of standard sizes held in place by a circular metal frame. The diameter of the sieve ranges from 4 to 18 in., and the height may vary from 1 to 2 in. Three popular sieve series are used the Tyler Series, the first commercial laboratory screens the U.S. Standard Series and the U.S. Alternative Series. Both the U.S. Alternative Series and the Tyler Series designations use the approximate number of opening per linear inch. However, the U.S. Standard Series is the preferred designation and is recommended by the International Standards Organization (ISO). Table 15.3 shows the U.S. Sieve Series and Tyler Series equivalents for a selected number of screens. 

A screen used for a sieve analysis has a designation of 60 mesh. What does this indicate ... 

U. S. Sieves are identified by either micrometer (micron) designations or arbitrary numbers. Thus, a material referred to as 60/80 means particles which will pass a 60 mesh screen but not an 80 mesh screen. You may also see this written as -60+80 mesh. Particle size is much better expressed in micrometers (microns), therefore 60/80 mesh would correspond to 250-177 micrometers (micron) particle size range. Table 2.5 shows the conversion of column packing particle sizes. The table shows the relation... 

Sieve Designation Sieve Opening Nominal Wire Diameter Tyler Screen... 

Batch tests (i.e., tests on individual samples) are conducted with soil-plus-leachate suspensions using the standard test soils. The soils are prepared from air-dried samples, sieved through 1/4" screen for mixing with the leachate from the 24-h batch leaching test. The concentrations of leachate in the solution are designed to evaluate the capability of environmental soils to adsorb available contaminants. The soil particles must be fully dispersed within the aqueous phase to achieve complete adsorption. 

The use of computer databases and computer-controlled plants facilitates daily laboratory work. The recently set up expert systems for catalysts [79] help to reduce the number of experiments by rapid preselection, and accelerate catalyst development. In the structure determination of zeolites or non-zeolite molecular sieves (APOs, SAPOs), computers provide a valuable and fast service in that zeolite models are designed graphically on the screen, and the corresponding X-ray diffraction... 

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