Layered fabric systems

Ding, D., Tang, T., Song, G., McDolnald, A., 2011a. Characterizing the performance of a single-layer fabric system through a heat and mass transfer model. Part 1 heat and mass transfer model. Text. Res. J. 81 (4), 398-411. 

Fig. 14.2 Comparison of SEM micrographs (a) mioroporous membrane, (b) layered fabric system with electrospun PU nanofiber web, and (c) spunbond nonwoven fabric, (d) SEM micrographs of electrospun PU nanofiber web. (e) Effects of area density of electrospun polyurethane web on air/moisture vapor transport properties of layered fabric systems, (f) Cross section of laminated nanofiber nonwoven web and (g) vapor permeability before/after wash (a-c Reprinted with permission from Lee and Obendorf [23]. Copyright 2007, The Korean Fiber Society, d, e Reprinted with permission from Lee and Obendorf [24]. Copyright 2007, SAGE Publications, f, g Reprinted with permission from Kimura et al. [25]. Copyright 2010, SAGE Publications)...

Kang et al. first used direct electrospinning of PU onto the substrate fabrics (polyester/nylon blended fabric, which contained stainless steel yarn in weft) to prepare the waterproof-breathable fabric. PU was solvent electrospun onto the substrate fabric to develop the waterproof-breathable fabric with lightweight and thermal insulation [22], The reported air permeability and WVT rate were 0.5 cm /cm /sec and 375.80 g/h/m, respectively, for electrospun PU coated fabric, which were far better than the PU coated fabrics. Lee et al. developed electrospun PU layered fabric systems in which nanofibrous web was layered on spunbonded nonwoven to check the possibility of developing protective clothing materials as barriers to liquid diffusion (Fig. 14.2a-c). Layered clothing systems with electrospun... 

Lee S, Obendorf SK (2007) Transport properties of layered fabric systems based on electrospun nanofibers. Fiber Polym 8(5) 501-506. doi 10.1007/bf02875872... 

Some metal oxide nanoparticles possess unique, significant applications when electrospun with certain polymers. Lee [76] successfully developed layered fabric systems with electrospun polyurethane/zinc oxide nanocomposite fiber webs layered on cotton substrates, which imparted UV protection and antibacterial functions. Okuyama et al. [77] used mixed solutions of indium tin oxide (ITO) nanoparticle sol and PEO as precursors of the nanofibers to prepare ITO nanofibers via... 

Lee S (2009) Multifunctionality of layered fabric systems based on electrospun polyurethane/zinc oxide nanocomposite fibers. J Appl Polym Sci 114 3652—3658... 

However, fluorocarbon compounds might be of considerable interest for LB-layer fabrication. Their dielectric and mechanical characteristics and thermal and chemical stability are not inferior to those of polyimides, and highly developed synthesis technology makes it possible to create systems with various predictable properties. Such films have been found to demonstrate a high degree of perfection and excellent dielectric characteristics.69,70... 

We achieved high aspect ratio sub-half-micron pattern fabrication in 1.0 micron film thickness using this new resist. We are convinced that this new resist could make possible simple and efficient single-layer-resist system for KrF excimer laser lithography. 

As mentioned above, the conventional diazonium salts have good optical properties as CEL dyes and negative working sensitizers for the two-layer resist system. However, almost all diazonium salts are stabilized with metal-containing compounds such as zinc chloride, tetrafluoroborate, hexafluoro-antimonate, hexafluoroarsenate, or hexafluorophosphate, which may not be desirable in semiconductor fabrication because of potential device contamination. To alleviate the potential problem, new metal-free materials have been sought for. 

A new silicone-based negative resist (SNR) for two layer resist systems was designed and prepared. It showed excellent dry etching durability to 02 RIE, high sensitivity to electron beam, X-ray and deep UV, and high resolution. Two layer resist with SNR/AZ resist is very effective to achieve submicron patterns with high aspect ratio, and will be used for the fabrication of submicron patterns over topography such as the metallization of electrode patterns in the last step of VLSI fabrication process. 

Si wafers of n-type and (100) orientation covered by thermally grown 100 nm SiO2 layer fabricated at 1100 °C in dry O2, were used as substrates. The wafers were loaded into an oil free evaporation chamber (Varian VT-460), and the system was evacuated down to lxlO 8 Torr. Ge ingot of 99.999 % purity was supported on a molybdenum plate, and it was evaporated using an electron gun, at an evaporation rate of 0.01-0.03 nm/s, at a pressure of lxlO"7 Torr. During evaporation, and for an additional 1 min after this process, the substrate temperature was kept at 350 °C. The temperatures were monitored by small-heat-capacity Ni-NiCr thermocouples, while the film thicknesses were measured by a vibrating quartz probe. For this study, four different samples have been prepared with different Ge evaporation times of 25, 50, 75, and 100 s for samples No. 1, 2, 3, and 4, respectively. After germanium evaporation, the samples were moved to a cold place inside the vacuum chamber. 

Textile body armour has been used since the middle of the twentieth century, but it can trace its roots back to silk fabric, leather and other mrrltilayer systems of antiquity. The response of textile armoirr to balhstic impact is complex and not fully understood. Numerous studies of fabric systems have been published, and understanding has slowly developed based on single fibre tests, meso material models and, recently, relatively complete numerical models of multilayer systems (Tabiei and Nilakantan, 2008). Analytical and empirical models have been developed (Cuniff, 1999 Roylance, 1977) which seek to indicate the key fibre and fabric properties required in armour. However, our understanding of the more subtle effects is still somewhat incomplete, with inter-yam and inter-layer interactions remaining to be fully characterised and with models which are only validated across relatively narrow sets of conditions and materials. 

For bullets having a KED of above 30 Jmm", ballistic fabric systems become overly bulky. The contact loads tend to be sufficient to cause shear failure of the fibres and capture of the projectile occurs only after numerous layers have been perforated. For a KED of 30 5 Jttmr it is possible to provide protection by use of polymer matrix composites. In essence this is an extension of the tactic used in knife armour, as the projectile is forced to break fibres and radially expand the perforation against significant constraint. It has been shown that at low KED... 

Asphalt overlay fabrics n. Fabric systems installed between the old and new asphalt layers during pavement resurfacing. The fabric absorbs the tack coat sprayed on the old surface thus forming a permanent moisture barrier to protect the subgrade from strength loss due to water intrusion. The fabric system also helps retard reflective cracking by serving as a flexible layer to diffuse stress. 

Note that depending on the resin system used in VARTM, the mold temperature may need to be elevated during the curing q cle of the VARTM process. For a large or complex composite part (with inserts, hybrid fabric systems, co-cured parts, etc.), multiple injection lines and vents could be used to improve the resin infusion. The flow distribution medium layer could also be placed in different patterns to create versatile resin infusion paths that can promote the resin infusion quality of a large or complex composite part. 

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