Improvements in the detection of gunshot residue and considerations affecting its interpretation.
Item
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Title
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Improvements in the detection of gunshot residue and considerations affecting its interpretation.
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Identifier
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AAI9820572
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identifier
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9820572
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Creator
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Pizzola, Peter Anthony.
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Contributor
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Adviser: Peter R. De Forest
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Date
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1998
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Language
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English
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Publisher
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City University of New York.
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Subject
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Chemistry, Analytical
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Abstract
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This research focused on two major areas of criminalistics and crime scene reconstruction; the estimation of the distance to a target from which a firearm was discharged, called the muzzle-to-target distance, and gunshot residue dynamics. The estimate of the muzzle-to-target distance is critical to crime scene reconstruction since it can either help corroborate or refute suspects' or witnesses' statements. Methods currently used in criminalistics laboratories for the estimate of the muzzle-to-target distance have changed little over the past fifty years. These methods employ transfer techniques, rather than a direct pattern development and visualization approach, since color reactions do not provide an adequate contrast with dark fabrics. Unfortunately, a critical assessment of these transfer methods has not been made.;A detailed study of these transfer methods was conducted. This research demonstrated that these methods suffer from several problems which can influence their interpretation. Alternate approaches for direct pattern visualization involving photoluminescence were studied and developed. Several techniques for the detection of particles and the metal deposits have been identified. These include: (1) use of native fluorescence for the detection of partially burned propellant particles, (2) low temperature enhancement of photoluminescent methods for particles and the metal deposits, (3) a phosphorescent method for the detection of partially burned propellant particles, (4) chemical treatment to induce fluorescence of propellant particles and metal deposits, (5) a fluorescence method for vastly improving the detection of reaction sites on the transfer medium for partially burned propellant particles.;Several sequentially integrated approaches, incorporating the above improvements for the detection and enhancement of discharge patterns, have been developed and described. Most of these newly developed techniques are integrated with the long accepted classical methods, and build on them.;High speed photography of the formation and movement of gunshot residue, in the form of particles and a cloud, has helped explain some of the difficulties experienced by criminalists in their analyses of physical evidence. Additionally, it has provided valuable information for crime scene reconstruction purposes. These findings should also help non-scientists, such as attorneys and judges, comprehend some of the complexities and anomalies involved.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
