Hydrocarbon layer model

Charbeneau, R. J., Wanakule, N., Chiang, C. Y., Nevin, J. R, and Klein, C. L., 1989, A Two-Layer Model to Simulate Floating Free Product Recovery Formulation and Applications In Proceedings of the National Water Well /Association and American Petroleum Institute Conference on Petroleum Hydrocarbons and Organic Chemicals in Ground Water Prevention, Detection and Restoration, November, pp. 333-345. 

TCLP TDB TDF THC TBP TEM TLM TM-AFM TOC TRLFS TRU TSP TST TVS Toxicity characteristics leaching procedure Thermodynamic database Tyre-derived fuel Total hydrocarbon Tri-n-butyl phosphate Transmission electron microscopy Triple layer model Tapping mode atomic force microscopy Total organic carbon Time-resolved laser fluorescence spectroscopy Transuranic Total suspended particles Transition state theory Transportable vitrification system... 

Quantitative determinations of the thicknesses of a multiple - layered sample (for example, two polymer layers in intimate contact) by ATR spectroscopy has been shown to be possible. The attenuation effect on the evanescent wave by the layer in contact with the IRE surface must be taken into account (112). Extension of this idea of a step-type concentration profile for an adsorbed surfactant layer on an IRE surface was made (113). and equations relating the Gibbs surface excess to the absorbance in the infrared spectrum of a sufficiently thin adsorbed surfactant layer were developed. The addition of a thin layer of a viscous hydrocarbon liquid to the IRE surface was investigated as a model of a liquid-liquid interface (114) for studies of metal extraction ( Ni+2, Cu+2) by a hydrophobic chelating agent. The extraction of the metals from an aqueous buffer into the hydrocarbon layer was monitored kinetically by the appearance of bands unique to the complex formed. 

The IRE of the Prism Cell was coated with a layer of hydrocarbon "model soil" in the same way as was done in earlier work with the CIRCLE (5.12). The IRE is withdrawn mechanically from the solution of the hydrocarbon of interest (2-4 wt.% in hexane) at a slow, controlled rate. The hexane flashes off, leaving a layer of hydrocarbon behind. By varying the withdrawal rate and the concentration of the hydrocarbon, layers of varying thicknesses, as judged by the intensity of the bands of the hydrocarbon spectrum, can be obtained. 

Values of the equivalent water-alcohol thickness kw, the thickness of the hydrocarbon layers hly the thickness of the polar core h2 and the thickness h (according to three-layer model) of DMPC foam bilayers at different temperatures. 

Note The results for the thickness of foam films according to the three-layer model depend on the place of the conditional boundary between the hydrophilic and hydrophobic parts of foam bilayer (see Section 3.4.1.2). The above values are calculated under the assumption that these boundaries are situated between the polar head groups and hydrocarbon chains of DMPC molecules. 

We simultaneously incorporate both lipid and protein by using dialysis to remove detergent from a solubilized lipid-protein mixture in the presence of the alkylsilanated substrate. Under our conditions, from the evidence in this paper and elsewhere (9), the surface structures appear to be single bilayer membranes. Our hypothesis is that the hydrocarbon chains attached to the surface serve as initiation sites for a lipid bilayer membrane to form as the detergent is slowly removed. The model is of a membrane that is anchored to the surface by hydrophobic interactions with the surface-bound hydrocarbon layer. Integral membrane proteins are retained in these structures by their interaction with the hydrophobic core of the membrane without being directly attached to the electrode surface. 

Brine shrimps, toxicity of polycyclic aromatic hydrocarbons, 197,198t Bulk, mixed-layer models, description, 259... 

Figure 3.4 A model hydrocarbon layer. White and light-gray balls represent hydrogen and carbon, respectively.

On the basis of these observations, a three-layer model known from XPS analysis of thin oxide films on metallic substrates " has been applied to the ODP-SAM on tantalum oxide. This model allows the composition of (a) the substrate, (b) the P-0 interfacial layer, and (c) the hydrocarbon top layer to be calculated, as well as the thicknesses of layers b and c, based on the intensities and the origin of the individual components of the elements as defined above. The density of the TagOg substrate was taken as 8.6 g/cm , that of the hydrocarbon chains in the film as 1.1 g/cm , and that of the thin P-0 polar head layer as 2.0 g/cm . The latter two values were estimated from AFM results, as outlined in section 3.1. Cross sections used for the calculations were taken from ref 15. The attenuation length values of the photoelectrons... 

A structural variation of synthetic single-chain amphiphiles indicates that a certain length of the flexible tail, usually a Unear alkyl chain of seven or more C atoms, is required for the formation of a bilayer. The development of the bilayer structure is improved with increasing chain length. A systematic investigation by Skoulios and Luzzati [22] resulted in the weU-known model of ionic amphiphilic molecules in which the two polar layers are separated by the hydrocarbon layer. 

IHP) (the Helmholtz condenser formula is used in connection with it), located at the surface of the layer of Stem adsorbed ions, and an outer Helmholtz plane (OHP), located on the plane of centers of the next layer of ions marking the beginning of the diffuse layer. These planes, marked IHP and OHP in Fig. V-3 are merely planes of average electrical property the actual local potentials, if they could be measured, must vary wildly between locations where there is an adsorbed ion and places where only water resides on the surface. For liquid surfaces, discussed in Section V-7C, the interface will not be smooth due to thermal waves (Section IV-3). Sweeney and co-workers applied gradient theory (see Chapter III) to model the electric double layer and interfacial tension of a hydrocarbon-aqueous electrolyte interface [27]. 

An essential component of cell membranes are the lipids, lecithins, or phosphatidylcholines (PC). The typical ir-a behavior shown in Fig. XV-6 is similar to that for the simple fatty-acid monolayers (see Fig. IV-16) and has been modeled theoretically [36]. Branched hydrocarbons tails tend to expand the mono-layer [38], but generally the phase behavior is described by a fluid-gel transition at the plateau [39] and a semicrystalline phase at low a. As illustrated in Fig. XV-7, the areas of the dense phase may initially be highly branched, but they anneal to a circular shape on recompression [40]. The theoretical evaluation of these shape transitions is discussed in Section IV-4F. 

The popularity of aerosols has been declining. A widely used group of propellants, the fluorinated hydrocarbons, have been restricted in use since it was found that they can harm the environment by reducing the o2one layer of the upper atmosphere (see AiRPOLLUTlON ATMOSPHERIC MODELING Ozone). 

---