FIBRES Ref: Kendall Hunt Publishing company. fibres 2 2 Fibres

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<ul><li> Slide 1 </li> <li> FIBRES Ref: Kendall Hunt Publishing company </li> <li> Slide 2 </li> <li> fibres 2 2 Fibres </li> <li> Slide 3 </li> <li> fibres 3 Fabric is made of fibres Fibres are made of twisted filaments Types of fibres and fabric: Naturalanimal, vegetable, or inorganic Artificialsynthesized or created from altered natural sources Kendall/Hunt Publishing Company3 Fabric </li> <li> Slide 4 </li> <li> fibres 4 Types of fibres Kendall/Hunt Publishing Company4 Synthetic Natural </li> <li> Slide 5 </li> <li> fibres 5 Kendall/Hunt Publishing Company5 Classification Natural fibres are classified according to their origin: Vegetable or cellulose Animal or protein Mineral </li> <li> Slide 6 </li> <li> fibres 6 Cotton Rayon Cellulose acetate Kendall/Hunt Publishing Company6 Cellulose Fibres </li> <li> Slide 7 </li> <li> fibres 7 Fibre Comparison Can you describe the difference(s) between the cotton on the left and the rayon on the right? Kendall/Hunt Publishing Company7 </li> <li> Slide 8 </li> <li> fibres 8 Protein Fibres Wool Silk Kendall/Hunt Publishing Company8 vicuallama alpaca silkworm </li> <li> Slide 9 </li> <li> fibres 9 Asbestos Rock wool Fiberglass Kendall/Hunt Publishing Company9 Mineral Fibres </li> <li> Slide 10 </li> <li> fibres 10 Nylon Polyester Acrylic Spandex Kendall/Hunt Publishing Company10 Synthetic Fibres Made from derivatives of petroleum, coal, and natural gas </li> <li> Slide 11 </li> <li> fibres 11 fabrics are composed of individual threads or yarns made of fibres and are knitted, woven, bonded, crocheted, felted, knotted, or laminated most are either woven or knitted degree of stretch, absorbency, water repellence, softness, and durability are individual qualities Kendall/Hunt Publishing Company11 Fabric Production </li> <li> Slide 12 </li> <li> fibres 12 Yarna continuous strand of fibres or filaments that may be twisted together Warplengthwise yarn Weftcrosswise yarn Blenda fabric made up of two or more different types of fibres Kendall/Hunt Publishing Company12 Weave Terminology </li> <li> Slide 13 </li> <li> fibres 13 Kendall/Hunt Publishing Company13 Plain Weave </li> <li> Slide 14 </li> <li> fibres 14 The warp yarn is passed over one to three weft yarns before going under one. Makes a diagonal weave pattern. Kendall/Hunt Publishing Company14 Twill Weave </li> <li> Slide 15 </li> <li> fibres 15 The yarn interlacing is not uniform Creates long floats Interlacing weave passes over four or more yarns Kendall/Hunt Publishing Company15 Satin Weave </li> <li> Slide 16 </li> <li> fibres 16 Knitted Fabric Knitted fabrics are made by interlocking loops into a specific arrangement. It may be one continuous thread or a combination. Either way, the yarn is formed into successive rows of loops and then drawn through another series of loops to make the fabric. Kendall/Hunt Publishing Company16 </li> <li> Slide 17 </li> <li> fibres 17 Synthetic fibres are made of The word polymer means The repeating units of a polymer are called By varying the chemical structure of the monomers or by varying the way they are joined together, polymers are created that have different properties As a result of these differences, they can be distinguished from one another forensically Kendall/Hunt Publishing Company17 Polymers </li> <li> Slide 18 </li> <li> fibres 18 Filament Cross Sections Synthetic fibres are forced out of a nozzle when they are hot, and then they are woven. The holes of the nozzle are not necessarily round; therefore, the fibre filament may have a unique shape in cross section. Kendall/Hunt Publishing Company18 Round 4-lobed Octalobal Irregular Multi-lobed or Serrate Trilobal Dogbone or Dumbbell </li> <li> Slide 19 </li> <li> fibres 19 Microscopic observation Burning Thermal decomposition Chemical tests Kendall/Hunt Publishing Company19 Testing for Identification </li> <li> Slide 20 </li> <li> fibres 20 Density Refractive index Fluorescence Kendall/Hunt Publishing Company20 Testing for Identification </li> <li> Slide 21 </li> <li> fibres 21 Components that make up dyes can be separated and matched to an unknown There are more than 7,000 different dye formulations Chromatography is used to separate dyes for comparative analysis The way a fabric accepts a particular dye may also be used to identify and compare samples Kendall/Hunt Publishing Company21 Dyes </li> <li> Slide 22 </li> <li> fibres 22 Bag clothing items individually in paper bags. Make sure that different items are not placed on the same surface before being bagged. Make tape lifts of exposed skin areas and any inanimate objects. Removed fibres should be folded into a small sheet of paper and stored in a paper bag. Kendall/Hunt Publishing Company22 Collection of Fibre Evidence </li> <li> Slide 23 </li> <li> fibres 23 For additional information about fibres and other trace evidence, check out truTVs Crime Library at: www.crimelibrary.com/criminal_mind/forensics/trace/1.html Kendall/Hunt Publishing Company23 More about fibres </li> </ul>