Ribbon composites

Comparison of the urea-anion inclusion compounds with the thiourea-anion inclusion compounds indicates that urea molecules more readily combine with other anionic moieties to generate composite dimers or ribbons. Composite dimers or ribbons exist in seven complexes among the nine urea-anion inclusion compounds studied here. For instance, both urea-bicarbonate complexes 1.6 and 1.7 (Figure 36 and Figure 37) contain a hydrogen-bonded [((NH2)2CO)2(HC03)2] ribbon built of alternating urea dimers and cyclic dimeric bicarbonate moieties (LB... 

Table 2.2 Comparison of modulus equations for continuous fiber and ribbon composites. 

Note that the expressions for E., and v.,2 are the generally accepted rule-of-mixtures results. The Halpin-Tsai equations are equally applicable to fiber, ribbon, or particulate composites. For example, Halpin and... 

Thomas [3-18] successfully applied Equations (3-72) and (3-73) to analysis of the stiffness of glass-ribbon-reinforced composite materials. 

J. C. Halpin and R. L. Thomas, Ribbon Reinforcement of Composites, Journal of Composite Materials, October 1968, pp. 488-497. 

One crimped metal ribbon flame arrester mannfactnrer has a composite element design consisting of mnltiple crimped metal ribbon elements with diverter shields (tnrbnlence-indncing devices) between the elements (Enardo n.d.). This design is based on the patent issned to Ronssakis and Brooker (1995). 

A layer of tetrahedra can be considered as being built up by linking parallel chains. That this is not a mere formalism is shown by the existence of intermediate stages. Two linked silicate chains result in a ribbon of the composition [Si4Of ] it has two kinds of tetrahedra, one kind being joined via three and the other kind via two vertices, [SiO Oj SiOj/jOj ]3 Silicates of this type are termed amphiboles. They are fibrous and also used to be used as asbestos. 

Micro/nanostructures generated using these and related top-down approaches are geometrically and electrically homogeneous, with layouts that can be controlled over a wide range to realize not only ribbons and wires but also bars, platelets, membranes, and other structures. The main limitations of the top-down approach are as follows (1) The composition of the fabricated objects is limited to materials that are readily available in wafer or thin-film forms, (2) the etching processes can lead to some level of roughness on the surfaces of the structures, and (3) dimensions of less than 20 nm, for other than the thickness, are difficult to obtain reliably. 

These results clearly show that our solvent displacement process leads to the formation of AmB-lipid structures that are different are from the ribbon-like ones described by Janoff et al. (11,21) for the same composition. It was therefore interesting to investigate the toxicity and efficacy of this formulation. 

Different lipid-based formulations with a common active ingredient may vary from one another in the chemical composition (eg, phospholipid and cholesterol content) and physical form of the lipid component (eg, sphere, disc, or ribbon). Such differences may affect functional properties of these drug products. 

When peptides containing four cysteine residues in the molecule are randomly oxidized, three different disulfide isomers can be formed (Scheme 1), isomer 1 with the disulfides aligned in parallel manner, isomer 2 with crossed disulfides and isomer 3 with sequential disulfides these isomers are also named in a more descriptive manner as the ribbon, globule and string-of-beads isomers. 28 The preferred formation of one of the isomers strongly depends upon the sequential topology of the cysteine residues, but also upon the sequence composition that may favor more or less globular structures with hydrophobic cores. 

---