000			03027nam a2200253 4500
001			394686
090			_a394686
100			_a20170823d2013 y0pory50 ba
101			_aeng
200			_aResearch and development of impression evidence _bRecurso eletrónico _fDemos Athanasopoulos, Adam Dale, Eric Sorrentino
210			_a[Rockville, MD] _cNational Criminal Justice Reference Service (NCJRS) _d2013
215			_a1 CD-ROM _d12 cm
300			_aFinal technical report submitted to the U.S. Department of Justice. Grant Number: 2009-DN-BX-K204. Ficheiro de 2,26 MB em formato PDF (40 p.).
330			_aThe collection and preservation of tool mark and impression evidence is an important part of the field of criminalistics. The ability to discern class and individual characteristics and use these to either identify or exclude an item as a possible match is a powerful tool in a criminalist's arsenal. The ability, then, of a casting agent to resolve the fine scale details of a tool mark or impression becomes of the utmost importance. An innovative approach to this problem is utilizing Magneto-Rheological (MR) fluids as an agent to capture the impression in situ. These materials are fluid under most conditions, but form a solid when a magnetic field is applied to them and can be used in lieu of Dental Stone or Mikrosil for collecting impression evidence. The goals of this project were to establish an optimal formula composition of an MR casting fluid, determine the limitations and benefits of using MR solutions as a casting fluid, and finally, if successful in the prior goals, develop a method of creating 3D images for permanent storage of the casting impressions. The purpose of this project is to provide a new method for preserving evidence that provides higher resolution casts, which does not need to be prepared at a crime scene, and which has a lower cost than conventional techniques. The trial MR fluid compositions were developed through trial and error by adjusting the concentration of the components in the fluid. Of the trial solutions prepared for this project, the optimal MR fluid was comprised of 25.0 g 325 mesh iron, 0.75 g cellulose, 0.75 g sodium nitrite, 0.15 g sodium chloride, 0.5 g Silicon Dioxide, and 10.0 mL-distilled water. This solution created long lasting, durable, and high resolution casts, which enabled the visualization and analysis of small details not discernible on the original object. With every MR solution, the casting substrate needed to be non-porous so that the solution wasn’t absorbed by the substrate, and non-magnetic so the solution was not affected by the magnetic field of the substrate.
606			_aRECOLHA DA PROVA _9322094
606			_aANÁLISE DE VESTÍGIOS _9320649
606			_aMARCAÇÃO DE OBJECTOS _9343973
606			_aTÉCNICA DE INVESTIGAÇÃO _9344784
700			_aATHANASOPOULOS _bDemos _9358521
701			_aDALE _bAdam _9358522
701			_aSORRENTINO _bEric _9358523
955			_xOferta