Hair And Fiber

 

History of Hair and Fiber Analysis

One of the first reports of hair analysis was in the year 1857, in France. Later, in the early 20^th century, hair and fiber analysis became more recognizable. In 1931, John Glaister published “Hairs of Mammalia from the Medico-legal Aspect” which quickly became a distinguished source for information pertaining to hair analysis. A little over 40 years later John Hick published “Microscopy of Hairs: A Practical Guide and Manual” provided a blueprint to analyze hair evidence by a forensic examiner. (John Glaister to the right)

Diagram

Major Fibers

Five types of fibers are:

1. Carbon Fiber- a very strong material that's also extremely lightweight. It is about 5 times as strong as steel and weighs about 66% less. It is thinner than human hair and can be woven together like yarn, which in turn could be woven together like cloth. Some popular examples of using carbon fiber is on parts for tuner cars, Kevlar vests and paintball equipment. (Carbon fiber hood below, right)

2. Cotton- A fluffy staple crop that grows in bundles. It is estimated that 25 million tonnes are produced annualy, which translates to 2.5% of the world's ariable land.

3. Rayon- Originally created as an alternative to silk. The rights to it were acquired by DuPont Chemicals, which quickly turned the product into a household name. Common uses for it are drapes inside the home.

4. Nylon-  a synthetic fabric made from petroleum products. It was developed in the 1930s as an alternative to silk, although it quickly became unavailable to civilian consumers, because nylon was used extensively during the war.

5. Polyester-  a plastic that was invented in Britain in the early 1940s. In the 1950s, it became popular as a textile because of its easy care, its drape and its versatility. An example of a common of polyester are household curtains (shown below, left).



Hair and Fiber Collection Techniques

One method to collect and analyze hair and fiber is through the use of neutron activation analysis. Some of the hair sample is bombarded with neutrons while inside a nuclear reactor. The neutrons make contact with the hair sample, which causes it to release a certain level of gamma radiation. By using this forensic scientists are able to measure every part of the sample, regardless of its size.



Another method to use is picking up the sample with tape.


Reliability of Hair and Fiber Samples

As of recent, the analysis of hair and fiber samples have been very inconsistent as of late. Some studies have shown a sample of  hair of having 9.8% sulfur. Some of the reasons why is because from enviornmental factors to hair dyes and perms.

Famous Cases

In 1982 Robert Anthony Buell was convicted for the rape and muders of multiple women. Fibers were collected with tweezers from a woman's hair. The color of the fabric matched the fibers found in Robert's home.

http://altmedicine.about.com/cs/govtregulation/a/HairTests.htm
http://www.trutv.com/library/crime/serial_killers/predators/williams/33.html
http://www.wisegeek.com/what-is-rayon.htm
http://www.enotes.com/hair-analysis-reference/hair-analysis