Globule

The parameter /r tunes the stiffness of the potential. It is chosen such that the repulsive part of the Leimard-Jones potential makes a crossing of bonds highly improbable (e.g., k= 30). This off-lattice model has a rather realistic equation of state and reproduces many experimental features of polymer solutions. Due to the attractive interactions the model exhibits a liquid-vapour coexistence, and an isolated chain undergoes a transition from a self-avoiding walk at high temperatures to a collapsed globule at low temperatures. Since all interactions are continuous, the model is tractable by Monte Carlo simulations as well as by molecular dynamics. Generalizations of the Leimard-Jones potential to anisotropic pair interactions are available e.g., the Gay-Beme potential [29]. This latter potential has been employed to study non-spherical particles that possibly fomi liquid crystalline phases. 

Mix I ml. of benzaldehyde and i ml. of aniline in a small evaporating-basin, place the latter on a boiling water-bath and stir the mixture gently with a glass rod. Globules of water soon appear on the oily layer. After about 20 minutes place the basin in ice-water, and stir the contents well, whereupon solidification should rapidly occur. (If the material does not solidify, replace the basin on the boiling water-bath for a further 10 minutes.) Break up the solid material in the basin, transfer to a conical flask, and recrystallise from rectified spirit. The benzylidene-aniline is obtained as colourless crystals, m.p, 52° yield, o-8 g. 

With paraldehyde and the aromatic aldehydes (being insoluble in water), it is advisable to warm the mixture gently on a water-bath, shaking the tube vigorously from time to time to break up the oily globules of the aldehyde. 

An interesting historical application of the Boltzmann equation involves examination of the number density of very small spherical globules of latex suspended in water. The particles are dishibuted in the potential gradient of the gravitational field. If an arbitrary point in the suspension is selected, the number of particles N at height h pm (1 pm= 10 m) above the reference point can be counted with a magnifying lens. In one series of measurements, the number of particles per unit volume of the suspension as a function of h was as shown in Table 3-3. 

The carbon disulphide reagent is prepared by adding to a solution of 0-5 g. of crystallised nickel chloride in 100 ml. of water enough carbon disulphide so that after shaking a globule of carbon disulphide is left at the bottom of the bottle. The reagent is stable for long periods in a well-stoppered bottle. If all the carbon disulphide evaporates, more must be added. 

Place 5 g. of lard (or any fat or fatty oil), 3 g. of potassium hydroxide and 40 ml. of alcohol in a 250 ml. round-bottomed flask, attach a reflux condenser, and boil for about 30 minutes. The reaction is complete when no globules of oil are present when a few drops of the mixture are mixed with a little water. Distil the reaction mixture (Fig. II, 13, 3) and recover the alcohol dissolve the residue in 75 ml. of hot water. C arry out the following experiments with the resulting solution —... 

Fig. 9. Membrane extraction where the solvent phase is represented by hatched lines and the arrows show the direction of mass transfer, (a) Spherical film (b) emulsion globule where the strip solution is represented by circles and (c) hoUow fiber support.

In milk fat, cholesterol is associated with Hpoproteins in the milk fat globule. It is also a component of animal membranes and controls rigidity and permeabihty of the membranes. Cholesterol has interesting surface properties and can occur in Hquid crystalline forms. Plants contain sterols such as P-sitosterol [83-46-5] (4b) or stigmasterol [83-48-7] (4c). Their functions in plant metaboHsm are not yet well understood. Analysis of sterols has proven useful for detection of adulteration of edible fats (9). 

Fig. 1. Diagrammatic representation of fat globule separation in a centrifugal separator (5).

When water is injected into a water-wet reservoir, oil is displaced ahead of the injected fluid. Injection water preferentially invades the small- and medium-sized flow channels or pores. As the water front passes, unrecovered oil is left in the form of spherical, uncoimected droplets in the center of pores or globules of oil extending through intercoimected rock pores. In both cases, the oil is completely surrounded by water and is immobile. There is htde oil production after injection water breakthrough at the production well (5). 

A number of proteins are known to pass through a transient intermediate state, the so-called molten globule state. The precise stmctural features of this state are not known, but appear to be compact, and contain most of the regular stmcture of the folded protein, yet have a large side-chain disorder (9). 

Low concentrations of oil can be removed by dissolved air flotation (DAF). In this process, an effluent recycle is pressurized in the presence of excess air, causing additional air to go into solution, in accordance with Henry s Law. When this water is discharged to the inlet chamber of the flotation unit at close to atmospheric pressure, the dissolved air comes out of solution in the form of tiny air bubbles which attach themselves to and become enmeshed in suspended solids and oil globules. The primary design criteria is the air/solids ratio, which is defined as the mass of air released divided by the mass of solids fed. Sufficient air must be released to capture the solids in the influent wastewater. The performance of DAF for the treatment of several... 

The cytoplasm of the cell contains most of the RNA, which may account for 7—12% of total cell soHds, mostiy as ribosomes. Lipid globules are also found in the cytoplasm, as well as carbohydrate storage materials in the form of glycogen and trehalose, which may account for up to 23% or more of cell sohds, depending on culture and metaboHc conditions. 

Ammonium chloride is used as a flux ia the melting furnace because the large surface of the cathodes favors the formation of dross, ie, oxide-coated globules of ziac. The dross is separated by Hquation or air-swept milling iato metal and oxide fractions. In the latter, the oxide fraction is swept out of the mill and can be returned to roasting for the elimination of chloride. Metallic ziac is recycled. Overall melting efficiency is 96—98%. 

Phosphides. Zirconium forms several phosphides ZrP [39318-19-9] 2 [ 12037-80-8] and ZrP g [12066-61 -4]-, they are part of the Zr—P phase diagram (137). The solubiUty of phosphoms in zirconium metal is low, ca 50 ppm, and at higher concentrations it collects as separate globules at the metal grain boundaries. Analysis indicates that this material is Zr P. 

Aluminum babbitt has been a U.S. alternative (6,20). On cooling this molten material, 8% lead separates from the aluminum as globules at the surface for improved antiscoring properties. More recendy, a sintered lead—alurninum containing 8.5% lead, 4% siUcon, 1.5% tin, and 0.5% copper has been developed for automotive use. 

V Daggett, M Levitt. A model of the molten globule state from molecular dynamics simulations. Pi-oc Natl Acad Sci USA 89 5142-5146, 1992. 

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