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Chapter 10: identification of inorganic fibers.

General Discussion

This module is intended to familiarize the trainee with inorganic fibers. Some classification schemes utilize the term "mineral" fiber which can include fiber types encountered in textile products such as asbestos, glass wool, some anti-static fibers, and metallic fibers. As used in this training program manual, these fibers are considered manufactured and should be studied within the manufactured fiber chapters.

The use of asbestos in textile products has declined significantly due to health risks associated with these fibers. Nevertheless, the trainee should be familiar with these inorganic fibers for thoroughness in theoretical knowledge and for instances in which they may be encountered as fibrous evidence from sources such as building and insulation products, in old textile products or the few textile products in which chrysotile may occur. This module should be completed in conjunction with Chapter 11 in which the trainee is exposed to the determination of fiber optical properties.

Objectives

Upon satisfactory completion of this training module, the trainee will have developed and demonstrated theoretical knowledge and/or practical skills to:

1. be conversant in processing practices and end uses of the asbestos minerals including chrysotile, amosite, crocidolite, fibrous tremolite/actinolite, and fibrous anthophyllite from both historical and current perspectives;

2. be conversant in the crystalline nature, chemistry and differences between layer silicates and chain silicates;

3. determine the optical properties of asbestos fibers by polarized light microscopy, and use of the dispersion staining technique;

4. identify and classify asbestos, particularly chrysotile, based on optical properties; and

5. be conversant in the applicability of infrared spectroscopy, X-ray diffraction and elemental composition examinations with respect to inorganic fiber identification.

Training Steps and Check Lists

1. Reading Assignments: Complete Chapter 10 reading assignments listed in Appendix I.

2. Basic Skills

3. Practical Exercise: Complete this exercise located in Appendix II.

10-1 Identification of Asbestos Fibers

(Note: this exercise should be completed in conjunction with or subsequent to learning the material presented in Chapter 11.)

Competency Evaluation

The trainee shall be evaluated by quizzes on theoretical knowledge and basic practical skills as specified in the module objectives. The quizzes should include practical skills questions such as determination of optical properties and fiber identification.

Basic Skills in asbestos optical property examinations:    D    P    C

1. determining refractive indices, sign of elongation,
  birefringence by PLM (see also Chapter 11)

2. dispersion staining

3. asbestos type identification by comparison to
  reference materials
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Title Annotation:A FORENSIC FIBER EXAMINER TRAINING PROGRAM
Publication:Forensic Science Communications
Geographic Code:1USA
Date:Apr 1, 2005
Words:399
Previous Article:Chapter 9: identification of animal textile fibers.
Next Article:Chapter 11: manufactured fiber examinations--optical properties.
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