Into fractions

This type of classification device can be used to carry out solid-solid separation in mixtures of different solids. The mixture of particles is first suspended in a fluid and then separated into fractions of different size or density in a device similar to that in Fig. 3.3. 

Cutting petroleum into fractions is done by the method illustrated in Figure 4.2. The petroleum fractions should correspond to the characteristics described in article 4.1.2. If certain characteristics are estimated, it is mandatory to compare the calculational results with the properties of the cuts and to readjust the estimated characteristics. 

Since the total numbers of dyads and triads always occur as ratios in Eqs. (7.73) and (7.74), both the numerators and denominators of these ratios can be divided by the total number of dyads or triads to convert these total numbers into fractions That is, p-Jp = Pi/Ps- Thus the fractions in Table 7.9... 

AH three processes give perfluoropolyethers with a broad distribution of molecular weights. They are typically separated into fractions by vacuum distillation. 

When consistent units are used, the particle size will either be in meters or feet. The equation contains effects of cyclone size, velocity, viscosity, and density of solids. In practice, a design curve as given in Fig. 17-39 uses Dptk the size at which 50 percent of sohds of a given size are collected by the cyclone. The material entering the cyclone is divided into fractional sizes, and the collecdion efficiency for each size is determined. The total efficiency of coUection is the sum of the col-lecdion efficiencies of the cuts. 

A modem petroleum refinery is a complex system of chemical and physical operations. The cmde oil is first separated by distillahon into fractions such as gasoline, kerosene, and fuel oil. Some of the distillate fractions are converted to more valuable products by cracking, polymerization, or reforming. The products are treated to remove undesirable components, such as sulfur, and then blended to meet the final product specifications. A detailed analysis of the entire petroleum production process, including emissions and controls, is obviously well beyond the scope of this text. 

The sieve test is probably still the most commonly used sizing technique both to characterize particulate distributions and separate them into fractions on the... 

For comparison, we applied also a simplified LCAO-DFT method to get the conductivity by means of the Kubo-Greenwood formula. This method is a hybrid between ab initio and empirical methods and is described in detail in Ref. [12]. It allows a faster computation of the electronic properties and the consideration of larger supercells than the Car-Parrinello method. Within this scheme it is also possible to split the total DOS into fractions referring to the sodium and tin atoms, respectively, i.e. to get the partial densities-of-states. 

Atmospheric distillation separates the crude oil complex mixture into different fractions with relatively narrow boiling ranges. In general, separation of a mixture into fractions is based primarily on the difference in the boiling points of the components. In atmospheric distillation units, one or more fractionating columns are used. 

British Foreign Minister Ernest Bevin once said that "The Kingdom of Heaven runs on righteousness, but the Kingdom of Earth tuns on alkanes." Well, actually he said "tuns on oil" not "runs on alkanes," but they re essentially the same. By far, the major sources of alkanes are the world s natural gas and petroleum deposits. Laid down eons ago, these deposits are thought to be derived from the decomposition of plant and animal matter, primarily of marine origin. Natural gas consists chiefly of methane but also contains ethane, propane, and butane. Petroleum is a complex mixture of hydrocarbons that must be separated into fractions and then further refined before it can be used. 

Distributions prepared from single lot of diced dehydrated carrots by grinding through food chopper and separating ground material into fractions by sieves. 

The effect is that the polymer molecules are separated into fractions. These are measured by an appropriate detector located at the end of the column, and the detector records the response as a peak on a chart. The chromatogram thus consists of a series of peaks corresponding to different elution volumes, the shortest elution volume being due to the largest molar mass polymer molecules within the sample. Details of the molar mass distribution can be determined from the size and number of the individual peaks in the chromatogram. An example of a gel permeation chromatogram is shown as Figure 6.4. 

The chief sources of the paraffins are natural gas and petroleum. Petroleum (also called crude oil ) is a complex mixture of paraffins that can he separated by a process called distillation into fractions according to their boiling range. The C1-C4 paraffins under normal conditions are gases, C5-C17 are liquids, and Cig and higher are solids. Paraffins serve many uses to help mankind. Perhaps most importantly, they are the building blocks from which most of our industrial organic chemicals are manufactured. 

Fig. 7. a Mark-Houwink plot of highly branched PMMA obtained by SCVCP of MMA with the inimer 12. (-)RI signal ( ) intrinsic viscosity of feed, ( ) intrinsic viscosity of linear PMMA (O) contraction factor, g. b Separation of feed polymer into fractions by preparative SEC. (-) RI signal of fractions (-) accumulated RI signals (.) RI signal of feed polymer. (Repro-... 

A modern refinery is a complicated collection of conversion processes, each tailored to the properties of the feed it has to convert. The scheme shown in Fig. 9.1 summarizes the most important operations some reasons for these processes are given in Tab. 9.2, along with relevant catalysts. First the crude oil is distilled to separate it into fractions, varying from gases, liquids (naphtha, kerosene and gas oil), to the heavy residue (the so-called bottom of the barrel ) that remains after vacuum distillation. 

Procedures for separating high polymers into fractions of restricted molecular weight range vary, but all of them depend on the very small decrease in solubility with increase in molecular weight in a given poly-... 

FIGURE 6.17 Densitograms of Azulan extract scanned at 410 nm divided into fractions a to i (a) isocratic development, ethyl acetate in chloroform (1 5), (b) stepwise gradient development, 10 to 40% v/v of ethyl acetate in chloroform. (From Matysik. G., Soczewinski, E., and Polak, B., Chromatographia, 39, 497-504, 1994. With permission.)... 

FIGURE 15.1 Scheme showing PLC group fractionation of soluble organic matter into fractions of aliphatic hydrocarbons, aromatic compounds with application of urea clathra-tion, and methylation of carboxylic acids in polar fractions based on experimental data given in Reference 36 to Reference 52, Reference 77 to Reference 81, and Reference 88 to Reference 89. 

Figure 2.6. LC-tandem mass spectrometry to examine complex mixtures. The mixture of many different proteins is digested to yield peptides and the peptides are resolved into fractions hy cation exchange chromatography followed by reverse phase chromatography. The fractionation steps resolve the peptides into fractions that he processed hy tandem mass spectrometry to yield sequence information suitable for database searching.

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