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Weaving
Published in Michael Hann, Textile Design, 2020
Pile cloths involve an extra set of warp or weft yarns which form a raised loop pile during the weaving process. These loops may be cut or left uncut. Such cloths were used as thermal blankets, as upholstery, towels or, in heavy-duty form, as carpets or rugs. Various pile-type cloths are worth mentioning further. Corduroy is a woven cloth in which a cut-weft-yarn pile forms in a warp direction standing out from the surface of the cloth. Velveteen cloths are occasionally cut to look like corduroy. Woven velvet is a cut-warp-pile cloth, with cut yarns forming across the whole surface. The heaviest pile textile is known as a carpet or rug. In most textile books the words ‘carpet’ and ‘rug’ are used interchangeably, though occasionally the word ‘carpet’ is used where an expanse of covering is expected and the word ‘rug’ where a smaller area is intended. So, the word ‘rug’ is used in this present book to refer to a floor covering which measures no more than 1.25 metres by 2.0 metres (this appears to be a common size for many hand-tufted rugs) and the word ‘carpet’ applied where the article is larger than this. The word ‘tufted’ refers to a heavy-duty surface pile of the type used in carpets and rugs. Tufts may be inserted by hand or machine into a preformed carpet backing or can be inserted during the weaving process between one or more inserted weft yarns. Often books refer to various carpet types: Wilton, Axminster, machine-tufted, hand-tufted and kilim are the most common. Wilton pile carpets are machine woven using a Jacquard loom. The product can be either highly patterned and multi-coloured or plain with no surface design. After weaving, the pile may either be left looped or be cut. Axminster pile carpets may be of various types depending upon how the tufts are inserted into the structure. Machine-tufted carpets use a pre-made substrate to receive pile yarn inserted using tufting needles. Machine-tufted carpets may be of a single colour or may be multi-coloured. Hand-tufted carpets are where each dyed tuft is inserted by hand between one or more weft yarns (forming a plain-weave structure) during the weaving process. This may involve numerous colours, and the pattern may be exceedingly complex. Kilim (sometimes spelt gelim, kelim or khlim) are hand-woven floor coverings without a pile, in plain weave, with dyed wool weft yarns which hide undyed cotton warp yarns. Structurally, kilims are like tapestry products where weft is discontinuous but, in the case of kilims, adjacent weft yarns are not interlocked with each other so vertical slits develop.
Properties of materials considered for improvised masks
Published in Aerosol Science and Technology, 2021
Steven N. Rogak, Timothy A. Sipkens, Mark Guan, Hamed Nikookar, Daniela Vargas Figueroa, Jing Wang
Forty-one individual materials were tested in addition to a reference surgical mask (ASTM Level 2 Primagard), respirators (N95, 3 M 1860), and commercial non-surgical mask (NMM, Greenlife). The full list of materials is provided in Table 1, with more detail provided in Table S3 and a data file in the SI. The samples fall into five broad categories according to the structure of the fabrics: woven (W), knit (K), cut pile (velour, velvet, fleece, corduroy on a woven or knit base), nonwoven (spunbond, spunlace, article), and multilayer (i.e., full mask structures). The majority of clothing fabrics were cotton and polyester, while the majority of the nonwoven materials were polypropylene and cellulose. Traditional filters of surgical masks and respirators contain layers of nonwoven fibrous materials that create tortuous paths with air pockets to achieve high filtration efficiency and breathability (wool felt, fiberglass article, and polypropylene). Based on these principles, we screened fabrics with structures composed of looping and interlocking layers (knitted pile, double knit, gauze) and agitated surface fibers (wool, brushed fabric), some of which demonstrated promising filter qualities in previous research (Jayaraman 2012). Although the variations of materials within each of these categories are large, we have selected a few examples to illustrate some of the most important differences between material types.