Date of Award
Summer 8-14-2025
Document Type
Thesis
Degree Name
Master of Science (MS)
Department/Program
Forensic Science
Language
English
First Advisor or Mentor
Peter Diaczuk
Second Reader
Jack Hietpas
Third Advisor
Andrew Winter
Abstract
Textiles can often be found damaged in forensic casework, and analysis of these defects can yield valuable information. Different methods of fiber fracture leave behind varying alterations in structure on individual fiber ends, leading to their possible identification and connection to a case. Interactions between high-speed impacts and synthetic fabrics composed of thermoplastic fibers are classified as rapid shear or high-speed tensile breaks. In these situations, unique fiber end characteristics can form due to excessive heat generation that is unable to dissipate quickly enough to prevent fiber end morphology from changing.
This study aimed to explore how different external conditions could affect the formation of these distinct fiber end characteristics created by high-speed impacts. Fabric samples were shot under unaltered room temperature, water-saturated, and chilled conditions. Stereomicroscopy and polarized light microscopy were used to analyze the fabric defects created by the air rifle pellets. Widened, globular fiber ends were discovered in all of the pellet holes examined for all three fiber types and under all environmental conditions. This change in fiber end morphology is characteristic of rapid shear. Additionally, these distinct fiber ends exhibited a loss of birefringence, with reduced retardation and interference colors. This study determined that the various temperature-altering environmental conditions employed did not stop fiber ends from changing and displaying characteristics corresponding to rapid shear.
Recommended Citation
Jin, Charles K., "Effects of Rapid Shearing Depending on Environmental Factors: Acrylic, Modacrylic, and Polypropylene Fibers" (2025). CUNY Academic Works.
https://academicworks.cuny.edu/jj_etds/367
