Layers, saturated

A large deep bath contains molten steel, the surface of which is in contact with air. The oxygen concentration in the bulk of the molten steel is 0.03% by mass and the rate of transfer of oxygen from die ait is sufficiently high to maintain die surface layers saturated at a concentration of 0.16% by weight. The surface of die liquid is disrupted by gas bubbles rising to the surface at a frequency of 120 bubbles per in2 of surface per second, each bubble disrupts and mixes about 15 enr of the surface layer into the bulk. 

Internal reference layer (saturated KC1) / Internal reference layer (saturated KC1) /... 

In a rather unnecessary attempt to define the interface between the ion-selective membrane and the dielectric, an internal hydrogel layer saturated with, for example, a buffer solution, has been interposed between these two layers. It mirrors the miniaturization of conventional symmetrical membrane ion sensors. The volume of the hydrogel layer is very small. This approach creates more problems than it solves. What is the major problem ... 

Kozakevitch and Urbain (1961) discussed the nature of the surface layer saturated with adsorbed oxygen (or another non-metallic element) by comparing... 

The comparison of W(C) dependence with Ao(C) isotherm gives a relation between formation of black spots and films, and the adsorption layer state. It has been shown [332] that the W(Q dependences for black spot and black films of a very small radius (25 pm) coincide. The comparison of the W(C) curve of CBF from NaDoS (see Fig. 3.78) with the surface tension isotherm of the same surfactant (see Fig. 3.77) indicates that black spots begin to form when the state of adsorption layers deviates from the ideal one (Henry s region in Aa(Q isotherm). The probability for observation of a black film steeply increases with the increase in surfactant concentration to about 10 5 mol dm 3 where the adsorption layer saturation is... 

The product from Step 1 was dissolved in 150 ml THE, cooled to —20°C, 2M borane dimethylsulfide (110 mmol) dissolved in THE added, and the mixture refluxed 3 hours. The mixture was re-cooled to —20°C, 72 ml methyl alcohol added and stirred one hour at ambient temperature. Thereafter, 16.4 ml 1M HCl in diethyl ether was added, the solution concentrated, and the residue partitioned between CH2Cl2/THF/water, 3 1 1. The pH was adjusted to 10 with NaHC03, the aqueous layer saturated with NaCl, and extracted with CH2CI2/THF, 3 1. The combined organic layers were dried, concentrated, and purified by flash chromatography on silica gel using chloroform with a methyl alcohol gradient of 3-10%. The material was further purified by crystallization in EtOAc and the product isolated. 

Since the dimensions of the cavities of synthetic zeolites are small, only accommodating a iew molecules, the assumption of a layer-by-layer saturation of the crystal from surface to central parts is justified. The adsorption value in the surface layer whose thickness is y is... 

Reflectance values on Cobas Ready as on any diffuse reflector are measured as the quantities of light reflected from a reagent layer saturated with a serum sample (/,) or from a white or black reference plate (/ and 4), each normalized to the incident light intensity monitored by the reference photodetector... 

Dimethylamine hydrochloride (1 equivalent) was prepared by evaporation of a mixture of aqueous dimethylamine (45 g, 1.0 mol, as 25% aqueous solution) and excess concentrated hydrochloric acid under reduced pressure. To the solid residue was added an aqueous solution of the cyclohexanone (224 g, 2.0 mol) and formaldehyde (30 g, 1.0 mol, 40% aqueous solution). The two-phase mixture was heated carefully (reaction is exothermic) to boiling under a long reflux condenser, boiled for about 5 min, and then cooled to room temperature. Water (200 mL) was added, the layers separated, the aqueous layer saturated with sodium chloride, washed with ether (4 x 50 mL), and then made basic with 30% aqueous potassium hydroxide (1.3 equivalents). The Mannich base separated as a yellow upper layer with a strong amine odor. The layers were separated, the aqueous layer extracted with ether (5 x 100 mL), the combined organic layer and ether extracts dried over magnesium sulfate, and the solvent was distilled to provide the amino ketone (118 g, 70%). 

Toluene saturated with water at SO C has 680 ppm HjO and is to be dried to 0.3 ppm HjO by fractional distillation. The feed is introduced to the top plate of the column, and the overhead vapor is condensed, cooled to 30°C, and separated into two layers. The water layer is removed, and the toluene layer, saturated with water, is recycled. The average relative volatility of water to toluene is 120. How many theoretical... 

As mentioned above, the adsorption kinetics for a kinetic-controlled mechanism is given by the balance of surfactant adsorption and desorption fluxes to and from the interface and for the Langmuir kinetics this balance has the form of Eq. (4.15). The rate constants kad and kdes are functions of the activation energies adsorption and desorption and can be specified on the basis of the molecular kinetic [9, 120] or transition state theory [121]. Eq. (4.15) was applied to adsorption kinetics data of surfactants at the water/air interface by many authors, for example in [24, 39, 83, 97, 122, 123, 124, 125, 126, 127]. In these works, it was shown that the values of kad and kdes are not constant hut depend on the surfactant bulk, the degree of adsorption layer saturation, or its lifetime. To obtain better correspondence with the experimental data, some authors had assumed that the adsorption and desorption activation energies depend on the degree of adsorption layer saturation. These rather complicated kinetic equation are more or less empirical, although they transforms into a valid adsorption isotherm at equilibrium... 

The foam collapse rate Wp as a function of surfactant concentration can be called foam formation isotherm (Fig. 6.2). As it is seen from Fig. 6.2, that Wp sharply increases in a narrow concentration range below adsorption layer saturation. The Wp° value can thus be a characteristic of the aggregation stability of foams during the formation process. 

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