Fiber networks

From a practical standpoint, the fiber or polymer must interact or process freely with the dynamics of web formation, and the resulting fiber network must be in register with the interlocking arrangement or media, in order for the fabric stmcture to transmit the maximum potential inherent in the properties of individual fibers. Ultimately, if a nonwoven fabric is to be totally effective and its properties fuUy utilized, it must be appropriately configured to meet its end use apptication or appropriately placed in the end use item in such a way that the performance of the product reflects the position and characteristics of individual fibers. 

Biefer, GJ Mason, SG, Electrokinetic Streaming, Viscous Flow and Electrical Conduction in Inter-Fiber Networks, The Pore Orientation Factor, Transactions of the Faraday Society 55, 1239, 1959. 

Inaba H., Kobayasi T., Hirama M., Hamza M., Optical-fiber network system for air-pollution monitoring over a wide area by optical absorption method, Electronics Letters 1979 15 (23) 749-751. 

Atomic force microscopy (AFM) can be used to obtain high-resolution imagery of molecular orientation and ordering for materials adsorbed onto substrates. Early AFM studies on gluconamides were hampered by the tendency of the fibers to unravel on substrates forming bilayer sheets.41 These layers showed the head-to-tail packing of a monolayer which is similar to the crystal structure reported for anhydrous gluconamides.38 A procedure to retain the fiber networks on surfaces with the addition of a small fraction of... 

Although the proteins in skin are also composed of about 5% elastic fibers, they do not appear to affect the mechanical properties of the tissue. The elastic fibers are believed to contribute to the recoil of the skin, which gives it the ability to be wrinkle-free when external loads are removed. As humans age, the elastic fiber network of the skin is lost, and wrinkles begin to appear. The mechanical role of the elastic fibers is very different in vascular tissue, however. 

In the past, various resin flow models have been proposed [2,15-19], Two main approaches to predicting resin flow behavior in laminates have been suggested in the literature thus far. In the first case, Kardos et al. [2], Loos and Springer [15], Williams et al. [16], and Gutowski [17] assume that a pressure gradient develops in the laminate both in the vertical and horizontal directions. These approaches describe the resin flow in the laminate in terms of Darcy s Law for flow in porous media, which requires knowledge of the fiber network permeability and resin viscosity. Fiber network permeability is a function of fiber diameter, the porosity or void ratio of the porous medium, and the shape factor of the fibers. Viscosity of the resin is essentially a function of the extent of reaction and temperature. The second major approach is that of Lindt et al. [18] who use lubrication theory approximations to calculate the components of squeezing flow created by compaction of the plies. The first approach predicts consolidation of the plies from the top (bleeder surface) down, but the second assumes a plane of symmetry at the horizontal midplane of the laminate. Experimental evidence thus far [19] seems to support the Darcy s Law approach. 

The Dave model considers a force balance on a porous medium (the fiber bed). The total force from the autoclave pressure acting on the medium is countered by both the force due to the springlike behavior of the fiber network and the hydrostatic force due to the liquid resin pressure within the porous fiber bed. Borrowing from consolidation theories developed for the compaction of soils [23,24], the Dave model describes one-dimensional consolidation... 

The advent of new lower cost optoelectronics for LAN applications has spurred a growing interest in using fiber all the way to the workstation. These total fiber networks offer easy migration to even higher speed applications like ATM. 

Generation of synthetic elastin-mimetic small diameter fibers and fiber networks. Macromolecules 33, 2989-2997. 

Keywords Fiber, Network, Multi-scale Model... 

Some researchers have used approximate microscopic descriptions to develop more rigorous macroscopic constitutive laws. A microstructural model of AC [5] linked the directionality of mechanical stiffness of cartilage to the orientation of its microstructure. The biphasic composite model of [6] uses an isotropic fiber network described by a simple linear-elastic equation. A homogenization method based on a unit cell containing a single fiber and a surrounding matrix was used to predict the variations in AC properties with fiber orientation and fiber-matrix adhesion. A recent model of heart valve mechanics [8] accounts for fiber orientation and predicts a wide range of behavior but does not account for fiber-fiber interactions. 

Fig. 7 SEM (magnification 3000) of freeze-dried BC. a CMC-modified (thicker fibers), b unmodified, c MC-modified (strong widening of the fiber network under amplification of the planar layers)...

Kessel, S., and Borner, H.G. "Self-assembled PEO-peptide nanotapes as ink for plotting nonwoven silica nanocomposites and mesoporous silica fiber networks". Macromol. Rapid Commun. 29, 316-320 (2008). 

Figures 15.8 and 15.9 illustrate examples of how cone calorimeter data can be used in the development of flame-retarded materials. PA 66-GF without Pred showed typical fire behavior for noncharring polymers containing inorganic glass fiber as inert filler,69 when high external heat flux is applied. The shape of the HRR curve is divided in two different parts. In the beginning, the surface layer pyrolysis shows a sharp peak, followed by a reduced pyrolysis rate when the pyrolysis zone is covered by the glass fiber network residue layer. When Pred was added, the PA 66-GF samples were transformed into carbonaceous char-forming materials, which led to a...

In the past, various resin flow models have been proposed (2, 15-19). Two main approaches to predicting resin flow behavior in laminates have been suggested in the literature thus far. In the first case, Kardos et al.2), Loos and Springer15), Williams et al.16) and Gutowski17) assume that a pressure gradient develops in the laminate both in the vertical and horizontal directions. These approaches describe the resin flow in the laminate in terms of Darcy s Law for flow in porous media, which requires knowledge of the fiber network permeability and resin viscosity. Fiber... 

By means of immunofluorescence analyzed in the adjacent sections incubated with antibodies to CCK and TH, respectively, in combination with fluorescent retrograde tracing, Hokfelt and coworkers (1980b) could establish also the coexistence of TH and CCK in terminal fiber networks in the NAc and other targets of the mesolimbic system, and could determine that VTA neurons which contain both CCK and DA project to the caudal and medial portions of the NAc. 

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