Separation components

Figure A3.14.12. The first experimental observation of a Turing pattern in a gel strip reactor. Solutions containing separate components of the CIMA/CDIMA reaction are flowed along each edge of the strip and a spatial pattern along the horizontal axis develops for a range of experimental conditions. (Reprinted with pennission from [38], The American Physical Society.)...

The simplest approach to understanding the reduced melting point in nanocrystals relies on a simple thennodynamic model which considers the volume and surface as separate components. Wliether solid or melted, a nanocrystal surface contains atoms which are not bound to interior atoms. This raises the net free energy of the system because of the positive surface free energy, but the energetic cost of the surface is higher for a solid cluster than for a liquid cluster. Thus the free-energy difference between the two phases of a nanocrystal becomes smaller as the cluster size... 

In a GC/MS combination, passage of the separated components (A, B, C, D) successively into the mass spectrometer yields their individual spectra. 

GC is a means of separating components of mixtures by passing them through a chromatographic column so that they emerge sequentially. 

With highly efficient capillary chromatographic columns, very small amounts of complex mixtures can be separated in the gas phase. Generally, the separated components cannot be positively identified by GC alone. 

Because a GC and an MS both operate in the gas phase, it is a simple matter to connect the two so that separated components of a mixture are passed sequentially from the GC into the MS, where their mass spectra are obtained. This combined GC/MS is a very powerful analytical technique, the two instruments complementing each other perfectly. 

LC operates in the liquid phase, while MS is a gas-phase method, so it is not a simple matter to connect the two. An interface is needed to pass separated components of a mixture from the LC to the MS. With an effective interface, LC/MS becomes a very powerful analytical technique. 

In this section and the last, we have examined the lattice model of the Flory-Huggins theory for general expressions relating AHj and ASj to the composition of the mixture. The separate components can therefore be put together to give an expression for AGj as a function of temperature and composition ... 

From now on we shall describe the scattered light by Eq, (10.30) exclusively, rather than considering the separate components. We shall also consider 0 only in the xy plane, in which case we use the symbol 6 to describe this angle. By convention, the incident light approaches the scattering dipole from 6 = 180°, and the transmitted light leaves the sample at 0 = 0°. 

Laser communication systems based on free-space propagation through the atmosphere suffer drawbacks because of factors like atmospheric turbulence and attenuation by rain, snow, haze, or fog. Nevertheless, free-space laser communication systems were developed for many appHcations (89—91). They employ separate components, such as lasers, modulators, collimators, and detectors. Some of the most promising appHcations are for space communications, because the problems of turbulence and opacity in the atmosphere are absent. 

These maybe separate components or carried on a single function. 

In essence, the cephalosporin acts as a carrier (63) for the quinolone. The quinolone is replaced in the bacterial ceU after the action of P-lactamase on the cephalosporin portion of the molecule. This codmg combination represents a relatively new class of antibacterial agents which appear to offer advantages over the separated components (64). A good introductory discussion of these exciting agents can be found (65) (see also Antibiotics P-lactams ... 

Process Stream Separations. Differences in adsorptivity between gases provides a means for separating components in industrial process gas streams. Activated carbon in fixed beds has been used to separate aromatic compounds from lighter vapors in petroleum refining process streams (105) and to recover gasoline components from natural and manufactured gas (106,107). 

There are essentially four steps or unit operations in the manufacture of fatty acids from natural fats and oils (/) batch alkaline hydrolysis or continuous high pressure hydrolysis (2) separation of the fatty acids usually by a continuous solvent crystallisation process or by the hydrophilisation process (J) hydrogenation, which converts unsaturated fatty acids to saturated fatty acids and (4) distillation, which separates components by their boiling points or vapor pressures. A good review of the production of fatty acids has been given (1). 

The mass spectrometer (ms) is a common adjunct to a chromatographic system (see Mass spectrometry). The combination of a gas chromatograph for component separation and a mass spectrometer (gc/ms) for detection and identification of the separated components is a powerful tool, particularly when the data are collected usiag an on-line data-handling system. QuaUtative information inherent ia the separation can be coupled with the identification of stmcture and relatively straightforward quantification of a mixture s components. 

Fig. 8. Five schemes for a design stmcture for separating components A, B, C, D with volatilities in the order D, C, B, A.

The relative volatiHty of most mixtures changes with temperature, pressure, and composition. The larger the value of the easier it is to separate component / from componentj. From equation 2, at a ( component, ie, biaary, ternary, etc, homogeneous azeotrope, for all c components ia the... 

Liquid-liquid extraction is a process for separating components in solution by their distribution between two immiscible liquid phases. Such a process can also be simply referred to as liquid extraction or solvent extraction however, the latter term may be confusing because it also applies to the leaching of a soluble substance from a solid. 

Beneficiation Ball and pebble mills, batch or continuous, offer considerable opportunity for combining a number of processing steps that include grinding [Underwood, Jnd. Eng. Chem., 30, 905 (1938)]. Mills followed by air classifiers can sei ve to separate components of mixtures because of differences in specific gravity and... 

Mechanical Component Separation Component separation is a necessaiy operation in the recovery of resources from sohd wastes and in instances when energy and conversion products are to be recovered from processed wastes. Mechanical separation techniques that have been used are reported in Table 25-61. 

Rubber base adhesives can be used without cross-linking. When necessary, essentially all the cross-linking agents normally used in the vulcanization of natural rubber can be used to cross-link elastomers with internal double carbon-carbon bonds. A common system, which requires heat to work, is the combination of sulphur with accelerators (zinc stearate, mercaptobenzothiazole). The use of a sulphur-based cross-linking system with zinc dibutyldithiocarbamate and/or zinc mercaptobenzothiazole allows curing at room temperature. If the formulation is very active, a two-part adhesive is used (sulphur and accelerator are placed in two separate components of the adhesive and mixed just before application). 

Biological-physiological detection The methods involved here take account of the biological activity of the separated components independent of their physical or chemical properties [12]. 

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