Partition/partitioning

Alumina Silica gel Modified silica gel Kieselguhr Cellulose powder Modified cellulose, e.g. D E A E and C M Sephadex gels Adsorption or partition Adsorption or partition Adsorption, partition Partition Partition Ion-exchange Exclusion... 

Dichloromethane partition. Partition residues into dichloromethane as described for fruit and vegetables. Evaporate the dichloromethane extract just to dryness by rotary evaporation under reduced pressure in a <40 °C water-bath. 

Hexane-acetonitrile partition. Partition the sample between hexane and acetonitrile as described for fruit and vegetables to remove citrus oils. Evaporate the... 

The partitioning of a substance between two liquid phases (multistage partitioning, partition chromatography) and the extraction of solids require similar properties of a solvent [50-55]. When a substance has to be partitioned, a solvent system with limited miscibility of the components is required in order that the substance dissolves to a different extent in the two phases. The greater the chemical differences between any two solvents, the more limited their miscibility. Other requirements that the solvent system must fulfil are, inter alia, a favorable partition coefficient (the average partition coefficient of the component mixture should be between ca. 0.2 and 5), as high a separation... 

Sorption of VOCs involves the processes of adsorption and partitioning. Partitioning is the incorporation of the VOC into the natural organic matter associated with the solid and is analogous to the dissolution of an organic compound into an organic solvent. Adsorption is the formation of a chemical or physical bond between the VOC and the mineral surface of a solid particle (Rathbun, 1998). The equilibrium relation between aqueous and solid phase concentrations then is expressed as... 

Classification of Partitions. Partitions are relatively thin, solid walls mounted inside the enclosure, as for example in Fig. 4.33. The partitions are passive in the sense that neither their temperature nor heat flux is prescribed. Depending on their extent and orientation, such partitions can have profound effect on the heat transfer. Partitions can be classified in various ways. Complete partitions run continuously from one side to another partial partitions have... 

The hypervisor is considered to be a software compliant item (see Section 5.4) that guarantees temporal and spatial independence among partitions (IEC-61508-2 Annex F), ensuring interference freeness among safety and non safety partitions, and interference freeness among safety partitions. Partitioning and multicore allocation is used to support a reasonable balance between performance (e.g., supervision functional group is divided in multiple partition(s)) and temporal interference due to shared resources. 

At each time-step an updating algorithm is used that ensures that significant partitions (partitions where QM solvent molecules are close to the center) are contributing to the forces in Eq. (2.16). Although less intuitive, the fade-in functions are used because they ensure that for the most-compact partition (the partition where aU the QM molecules are closer to the center than the MM molecules) either... 

Partitions. Partitions shall be of solid wood constmction formed by not less than two layers of 1-inch (25 mm) matched boards or laminated constmction 4 inches (102 mm) thick, or of 1-hour fire-resistance-rated constmction. 

Partitioning Partitioning is a technique for providing isolation between functionally independent software components to contain and/or isolate faults and potentially reduce the effort of the software verification process. 

Kaihel, G., Distillation Columns with Vertical Partitions, Chem. Eng. TechnoL, 10 92, 1987. 

Crude chlorophyll is prepared commercially from alfalfa meal or nettles by extraction with alcohol and partition into benzene. It is used as a colouring matter, particularly for foods and pharmaceutical products. 

Van Den Dool, H. and P.D. Kratz (1963), Generalization of the retention index system including linear temperature programmed gas-liquid partition chromatography . J. Chromatogr, Vol. 11, p. 463. 

Partitional clustering using Euclidean distance as a measure of dissimilarity between pattern classes has been selected for the grouping of AE hits. 

Various partitions, resulted from the different combinations of clustering parameters. The estimation of the number of classes and the selection of optimum clustering is based on separability criteria such as the one defined by the ratio of the minimum between clusters distance to the maximum of the average within-class distances. In that case the higher the criterion value the more separable the clustering. By plotting the criterion value vs. the number of classes and/or the algorithm parameters, the partitions which maximise the criterion value is identified and the number of classes is estimated. 

Figure 4 Scatter plot for the resulting partition for the example of CFRP pressure vessel.

These methods are based on homogeneity criteria that partitions an image into homogenous regions. This can be expressed by the following mathematical formalism. 

CLASSIFICATION METHODS In image processing, it often very interesting to built classes from the data structure. This technique can be partitioned into two categories ... 

Another advantage with the system is that the quality of the scanning, in terms of the angle towards the weld and track partition is increased compared to manual ultrasonic testing due to the fact that the scanning technician is able to concentrate on the object rather than on the oscilloscope while scanning. 

In the second picture, an interfacial layer or region persists over several molecular diameters due to a more slowly decaying interaction potential with the solid (note Section X-7C). This situation would then be more like the physical adsorption of vapors (see Chapter XVII), which become multilayer near the saturation vapor pressure (e.g.. Fig. X-15). Adsorption from solution, from this point of view, corresponds to a partition between bulk and interfacial phases here the Polanyi potential concept may be used (see Sections X-7C, XI-1 A, and XVII-7). 

Of particular interest has been the study of the polymer configurations at the solid-liquid interface. Beginning with lattice theories, early models of polymer adsorption captured most of the features of adsorption such as the loop, train, and tail structures and the influence of the surface interaction parameter (see Refs. 57, 58, 62 for reviews of older theories). These lattice models have been expanded on in recent years using modem computational methods [63,64] and have allowed the calculation of equilibrium partitioning between a poly-... 

Surfactants have also been of interest for their ability to support reactions in normally inhospitable environments. Reactions such as hydrolysis, aminolysis, solvolysis, and, in inorganic chemistry, of aquation of complex ions, may be retarded, accelerated, or differently sensitive to catalysts relative to the behavior in ordinary solutions (see Refs. 205 and 206 for reviews). The acid-base chemistry in micellar solutions has been investigated by Drummond and co-workers [207]. A useful model has been the pseudophase model [206-209] in which reactants are either in solution or solubilized in micelles and partition between the two as though two distinct phases were involved. In inverse micelles in nonpolar media, water is concentrated in the micellar core and reactions in the micelle may be greatly accelerated [206, 210]. The confining environment of a solubilized reactant may lead to stereochemical consequences as in photodimerization reactions in micelles [211] or vesicles [212] or in the generation of radical pairs [213]. 

The cleaning process proceeds by one of three primary mechanisms solubilization, emulsification, and roll-up [229]. In solubilization the oily phase partitions into surfactant micelles that desorb from the solid surface and diffuse into the bulk. As mentioned above, there is a body of theoretical work on solubilization [146, 147] and numerous experimental studies by a variety of spectroscopic techniques [143-145,230]. Emulsification involves the formation and removal of an emulsion at the oil-water interface the removal step may involve hydrodynamic as well as surface chemical forces. Emulsion formation is covered in Chapter XIV. In roll-up the surfactant reduces the contact angle of the liquid soil or the surface free energy of a solid particle aiding its detachment and subsequent removal by hydrodynamic forces. Adam and Stevenson s beautiful photographs illustrate roll-up of lanoline on wood fibers [231]. In order to achieve roll-up, one requires the surface free energies for soil detachment illustrated in Fig. XIII-14 to obey... 

In addition to lowering the interfacial tension between a soil and water, a surfactant can play an equally important role by partitioning into the oily phase carrying water with it [232]. This reverse solubilization process aids hydrody-namically controlled removal mechanisms. The partitioning of surface-active agents between oil and water has been the subject of fundamental studies by Grieser and co-workers [197, 233]. 

The following derivation is modified from that of Fowler and Guggenheim [10,11]. The adsorbed molecules are considered to differ from gaseous ones in that their potential energy and local partition function (see Section XVI-4A) have been modified and that, instead of possessing normal translational motion, they are confined to localized sites without any interactions between adjacent molecules but with an adsorption energy Q. 

Since translational and internal energy (of rotation and vibration) are independent, the partition function for the gas can be written... 

Of these, A are indistinguishable since the molecules are not labeled, and the complete partition function for N molecules becomes... 

It is now necessary to examine the partition function in more detail. The energy states for translation are assumed to be given by the quantum-mechanical picture of a particle in a box. For a one-dimensional box of length a. 

Thus the kinetic and statistical mechanical derivations may be brought into identity by means of a specific series of assumptions, including the assumption that the internal partition functions are the same for the two states (see Ref. 12). As discussed in Section XVI-4A, this last is almost certainly not the case because as a minimum effect some loss of rotational degrees of freedom should occur on adsorption. 

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