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MECHANICAL PROPERTIES OF THE INTERVERTEBRAL DISC AS AN ESTIMATOR OF POSTMORTEM INTERVAL
Title
MECHANICAL PROPERTIES OF THE INTERVERTEBRAL DISC AS AN ESTIMATOR OF POSTMORTEM INTERVAL.
Creator
Jackson, Jennifer, Conway, Ted, University of Central Florida
Abstract / Description
Currently, forensic scientists are only able to determine time since death (or postmortem interval) up to the first 60 hours. This is based largely on insect activity. Herein, it is proposed to use the degradation of the intervertebral disc (IVD) after death to determine a relationship between the mechanical properties of cadaveric tissue and time since death in order to extend the 60-hour window. To that end, 1 fresh human spine and 6 pig spines were each separated into sections (6 human and...
Show moreCurrently, forensic scientists are only able to determine time since death (or postmortem interval) up to the first 60 hours. This is based largely on insect activity. Herein, it is proposed to use the degradation of the intervertebral disc (IVD) after death to determine a relationship between the mechanical properties of cadaveric tissue and time since death in order to extend the 60-hour window. To that end, 1 fresh human spine and 6 pig spines were each separated into sections (6 human and 48 pig), with each section having one intact disc. The sections were buried, unearthed, and cleaned, leaving only the disc and bone. To determine the mechanical properties, each disc underwent three different tests: cyclic conditioning, compression, and stress relaxation testing. The Schapery collocation method was used to create a theoretical curve from the data for the experimental curve. Observations were made involving the corresponding k values of the curve. Although there are trends in the data for k values that approximate the experimental stress relaxation curve, a correlation could not be determined.
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Date Issued
2005
Identifier
CFE0000666, ucf:46495
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0000666
A PRELIMINARY STUDY FOR ESTIMATING POSTMORTEM INTERVAL OF FABRIC DEGRADATION IN CENTRAL FLORIDA
Title
A PRELIMINARY STUDY FOR ESTIMATING POSTMORTEM INTERVAL OF FABRIC DEGRADATION IN CENTRAL FLORIDA.
Creator
Humbert, Lorraine, Schultz, John, University of Central Florida
Abstract / Description
Forensic anthropologists rely on forensic evidence to estimate the postmortem interval of a decedent. This may include the study of the degree of deterioration of the human body, the life stage of insects, and the degradation of associated material evidence. Material evidence comes in many forms, and certain taphonomic processes will affect the material and must be considered when making inferences about a PMI. These include variables such as the characteristics of the soil, microorganisms,...
Show moreForensic anthropologists rely on forensic evidence to estimate the postmortem interval of a decedent. This may include the study of the degree of deterioration of the human body, the life stage of insects, and the degradation of associated material evidence. Material evidence comes in many forms, and certain taphonomic processes will affect the material and must be considered when making inferences about a PMI. These include variables such as the characteristics of the soil, microorganisms, and the presence of a decaying organic material. Previous research has undertaken studies in how fabric degrades over time; however, there is no standard methodology in use. The purpose of this research project is to establish a comprehensive scoring system and description standard after analyzing the degradation of four different fabric types. This will be useful for future studies in need of a standard methodology. In addition, the methods used in this project can be applied to actual forensic cases. After retrieval, the fabric type with the highest degradation was the cotton with about 1/3 of all cotton fabric swatches demonstrating more than 50% total degradation. For all fabric types, swatches that were positioned flat tended to degrade more than those that were positioned crumpled. Cotton fabric swatches degraded more in Trench 1 and Trench 2 than the Ground Surface, however, all other fabric types demonstrated slightly more degradation on the Ground Surface than the other two Areas. Soil moisture fluctuated the most on the Ground Surface while Trench 1 and Trench 2 were able to retain more water in the soil. Overall, cotton was the only fabric type to degrade significantly enough to show how it degrades over time, while the other fabric types have longer degradation intervals that must be studied further.
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Date Issued
2013
Identifier
CFH0004515, ucf:45220
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFH0004515