Onion skin

The discovery of perfect geodesic dome closed structures of carbon, such as C o has led to numerous studies of so-called Buckminster fullerene. Dislocations are important features of the structures of nested fullerenes also called onion skin, multilayered or Russian doll fullerenes. A recent theoretical study [118] shows that these defects serve to relieve large inherent strains in thick-walled nested fullerenes such that they can show faceted shapes. 

The mesophase pitch is then extmded and melt spun through spinnerettes into fibers. The flow pattern of the mesophase during fiber formation has a strong influence on the morphology of the fiber (52—54) and can result in fibers with radial, onion-skin, or random microstmctures. Commercially available PBCFs have a round cross section, but this can be easily modified by changing the cross section of the spinnerette holes. Multilobal and C-shaped fibers have been produced with exceptional mechanical properties (55). 

For the characterization of compounds extracted from plants, wool and dye baths, acquisition in the NI mode is used. The main signals in the mass spectra of each colourant are attributed to deprotonated molecular ions [M H]. More detailed studies can be performed by ESI MS" with a quadrupole ion trap mass analyzer, and such a set-up was used e.g. for the investigation of photo-oxidation processes of components of weld and onion skins.[29]... 

Suh HJ, Leeb JM, Chob JS, Kima YS and Chung SH. 1999. Radical scavenging compounds in onion skin. Food Res Int 32(10) 659-664. 

Fig. 5.9. Schematic illustration (not to scale) of the onion-skin structure in the interior of a highly evolved massive star (25 M0). Numbers along the vertical axis show some typical values of the mass fraction, while those along the horizontal axis indicate temperatures and densities (gmcm-3). Adapted from Kippenhahn and Weigert (1990).

Fig. 2.88. Chromatograms obtained from standard, onion, wine and plasma samples, (a) standard polyhydro xyflavones (5.00/ig/ml of each), (b) onion skin etract, (c) wine, and (d) plasma spiked with quercetin (5.00/ig/ml). Detection at 370 nm. Peaks 1 = rutin 2 = myricetin 3 = fisetin (internal standard) 4 = morin 5 = quercetin 6 = kaempferol. Reprinted with permission from H. Tsuchiya [210].

Fig. 7.3. Cross-section of a massive star. The onion-skin structure is specific to massive stars at the end of their existence.

KC1 Os/SbaSj/Pb(SCN)a 5/53/17/25 (Ref 87) Friction Type — LA/KC10j/SbaSj/carborundum 28.3/33.4/33-3/5.0 Relay Type — LA Pressed at 5000 psi and covered with an onion skin and Detonator Type — LA generally sensitized by the addn of lead styphnate (LSt), PbOjQHfNOjVHjO, to lower the ignition temp... 

A special case of pigmenting is the coating of one phosphor with another. This type of phosphor (onion-skin) is used in penetration tubes. At lower acceleration voltages the luminescence of the outer phosphor dominates, and at higher voltages, that of the inner phosphor. In addition, phosphor blends are used, the components... 

Liquid crystals, liposomes, and artificial membranes. Phospholipids dissolve in water to form true solutions only at very low concentrations ( 10-10 M for distearoyl phosphatidylcholine). At higher concentrations they exist in liquid crystalline phases in which the molecules are partially oriented. Phosphatidylcholines (lecithins) exist almost exclusively in a lamellar (smectic) phase in which the molecules form bilayers. In a warm phosphatidylcholine-water mixture containing at least 30% water by weight the phospholipid forms multilamellar vesicles, one lipid bilayer surrounding another in an "onion skin" structure. When such vesicles are subjected to ultrasonic vibration they break up, forming some very small vesicles of diameter down to 25 nm which are surrounded by a single bilayer. These unilamellar vesicles are often used for study of the properties of bilayers. Vesicles of both types are often called liposomes.75-77... 

Amplification of DNA of chromosomes. During formation of oocytes parts of the DNA are "amplified" by repeated replication. This provides a way for the ovum to accumulate ribosomal RNA and various proteins in large amounts. Similarly, genes for two abundant proteins of the egg shell or chorion of insects are amplified. Bidirectional replication initiated at discrete positions yields an "onion skin" structure containing many copies of an 90-kb sequence containing the two genes. The polyploidy observed in some highly specialized cells such as the Purkinje cells... 

The solutions of conductivity problems shown in the previous sections were obtained for zero-order kinetics. When the approximation by zero-order kinetics is not justified, which is the case, especially for autocatalytic reactions, a numerical solution is required. Here the use of finite elements is particularly efficient. The geometry of the container is described by a mesh of cells and the heat balance is established for each of these cells (Figure 13.5). The problem is then solved by iterations. As an example, a sphere can be described by a succession of concentric shells (like onion skins). In each cell, a mass and a heat balance are established. This gives access to the temperature profile if one considers the temperature of the different cells, or the temperature and conversion may be obtained as a function of time. 

The "onion skin" growth mechanism is supported by filming experiments in which film formation is greatly effected by the nature of the monomer composition added last in the polymerization. In power feed examples, as well as in staged feeds, hard and hydrophobic compositions hinder film formation while softer and more hydrophilic compositions aid film formation. Curiously, in this respect, it was found that the filming characteristics of all-acrylic latexes responded to non-uniform polymerization techniques much more dramatically than did their styrene-acrylic counterparts. 

Easter egg dyes are natural dyes that can be found around the home. They include blue from cabbage leaves or blueberries, orange from yellow onion skins, red from cranberries or raspberries, pale green from spinach leaves, and light yellow from orange or lemon peels. Dyes often have different colors in acidic and alkaline solutions. This enables them to be used as acid-base indicators. Many dyes are utilized as biological stains, see also Cosmetics Perkin, William Henry Pigments. 

M. J. Moses, J. C. Fettinger and B. W. Eichhorn, InterpenetratingAS20 fullerene and Nij2 icosahedra in the onion-skin [As Nii2 As2o]3- ion. Science 300, 778-80 (2003). 

Agglomerates formed by coalescence and by layering can usually be distinguished by their appearance. Layered granules tend to a smooth spherical shape and examination of their interior cross sections reveals a layered onion skin construction. Coalesced granules tend to a more irregular spheroidal shape and often exhibit a rough raspberry -type surface. 

Coarser spray droplets yield larger granules which tend to a raspberry coalesced, rather than an onion skin layered, structure. This effect is diminished the larger the ratio of granule size to droplet size. 

Objectives of size enlargement, 1 Onion skin growth, 54, 152... 

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