Hair and Fibers&Textiles Flashcards
What are used to link between crime and suspect?
Fibers
What kind of evidence are fibers?
Trace evidence
If fibers are transferred from victim to suspect or suspect to victim, what kind of transfer is it?
Direct transfer
Fibers were transferred from the original source to a suspect and then to a victim. What kind of transfer is it?
Secondary transfer
Within 24 hours, what percent of all fibers may have fallen from a victim or been lost from a crime scene? Because of this, what is important?
Estimated 95 percent; early collection of fibers in an investigation is critical.
What kind of fibers are investigated?
Fibers that are not expected to be found.
What are few characteristics forensic scientists might question about fibers?
type of fiber, fiber color, number of fibers found, where the fiber was found, textile the fiber originated from, multiple fiber transfers, type of crime committed, time between crime and discover of fiber.
What determines the value of fiber evidence?
Fiber’s uniqueness
What the many number of fibers suggest?
possible violence or a longer period of contact
Fibers are gathered with what?
Special vacuums, sticky tape, and forceps
What are the methods that can analyze fibers without damaging them?
polarizing light microscopy and infrared spectroscopy
What uses a microscope that has a special filter that allows the scientist to look at the fiber using specific light wavelengths to examine fibers?
Polarizing light microscopy; how the fiber appears tells scientist what type of fiber it is.
What emits a beam that bounces off the material and returns to the instrument?
Infrared spectroscopy; how the beam of light has changed reveals the chemical structure of the fiber.
what kind of testings can scientist do if there are large quantities of fibers?
Burning them in a flame or dissolving in various liquids
What can you call things like clothing, carpets, and upholstery?
Textiles
What are fibers that have been spun together?
yarns
What are two classifications of fibers?
natural fibers and synthetic fibers
What fibers come from animals, plants, and minerals that are mined from the ground?
Natural fibers
what are three sources of animals that provide fibers?
hair, fur, and webbing
All animal fibers are made of what?
proteins
Is fur a textile?
no
what fibers are the most popular of animal fibers?
hair fibers
wool, cashmere, mohair, angora are examples of what fibers?
Animal hair fibers
Why do silk fibers not tend to shed as easily as hair fibers?
because silk fibers are very long
What part of plants do fibers come from?
seeds, fruits, stems, and leaves
What are amorphous fibers?
a loose arrangement of fibers that are soft, elastic, and absorbent
What do all plant fibers contain?
polymer cellulose, made up of simple glucose units
What are characteristics of cellulose?
can absorb water; insoluble in water; resistant to damage from harsh chemicals; can be dissolved only by strong acids.
Where is cotton found? Where does cotton usually be used?
seedpod of the cotton plant; clothing and household textiles
What fiber is from covering surrounding coconuts, stronger than flax or cotton when woven together, and relatively waterproof, so used in doormats and baskets?
Coir fiber
Name few stem fibers
Hemp, jute, flax
how do potential fibers grow in stem?
in bundles
what is the most common stem fiber that is found in the textile linen?
Flax
What textile is expensive, smooth, shiny, feels cold in hot weather, resist wear, commonly used for pants, jackets, and shirts.
Linen
What does it mean to be crystalline? What textile is highly crystalline?
dense, strong that resists rot and light damage; linen
What fibers produce a textile that is too course for garments and is used to make rope, mats, and handbags?
Jute fibers
What fibers are similar to flax, has been used for a long time in Asia for clothing, and is a popular alternative to cotton in N. America??
Hemp
What fiber is extracted from the leaves of abaca?
Manila. (fun fact: abaca is a relative of the banana tree)
Fibers from what desert plant with succulent leaves are used to make ropes, twines, and netting?
sisal
What make up mineral fibers?
Repeating polymers; Neither proteins nor cellulose
What fibers are very short, very weak, brittle, used to insulate buildings, fine, easily stick to the skin, and cause an itchy skin rash?
Mineral fibers
What is a mineral naturally occurring in different types of rocks with a crystalline structure of long, thin fibers?
Asbestos
What is durable, and used to make pipe coverings, brake linings, ceiling tiles, floor tiles, fire-resistant work clothes, shingles, home siding, and insulation for building materials?
Asbestos
Beside natural fibers, half of the fabrics produced today are what kind of fibers?
synthetic fibers
Synthetic fibers are categorized as what?
Regenerated fibers and polymere
How are synthetic fibers produced?
first by joining many monomers together to form polymeres
Name few types of synthetic fibers.
Rayon, acetate, nylon, acrylics, and polyesters
What fibers are derived from cellulose, mostly plant in origin, include rayon, imitate natural fibers, has generally smooth and silky appearance?
regenerated fibers (or modified natural fibers)
What fiber is produced by cellulose chemically combined with acetate?
Celanese
What fiber is formed when cellulose is combined with three acetate units? It’s breathable, lightweight material, and used in high-performance clothing.
Polyamide nylon
What fibers originate with petroleum products and are non cellulose-based fibers?
synthetic polymer fibers
What fibers have no definite shape or size, may be easily dyed, and have very regular diameters?
Synthetic polymer fibers
What fiber is common synthetic fiber, represents a large group of fibers with a common chemical makeup, found in polar fleece, wrinkle-resistant pants, and is added to many natural fibers to provide additional strength?
polyester
What fiber is easily broken down by light and concentrated acid, similar to polyester, and can be called synthetic pantyhose (artificial silk)?
Nylon
What fiber is often found as an artificial wool or imitation fur, has a light, fluffy feel, tends to ball or pill easily, and is inexpensive?
Acrylic
What fiber is used in high-performance clothing like socks and carpets, because it’s quick drying and resistant to wear?
Olefins
