03100nam a2200241   4500001000700000090001100007100004100018101000800059200012400067210007900191215002000270300014700290330206200437606002902499606003702528606003702565606004202602700003402644701002302678701002902701955001102730995011702741394686  a394686  a20170823d2013       y0pory50      ba  aeng  aResearch and development of impression evidencebRecurso eletrónicofDemos Athanasopoulos, Adam Dale, Eric Sorrentino  a[Rockville, MD]cNational Criminal Justice Reference Service (NCJRS)d2013  a1 CD-ROMd12 cm  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.).  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.  aRECOLHA DA PROVA9322094  aANÁLISE DE VESTÍGIOS9320649  aMARCAÇÃO DE OBJECTOS9343973  aTÉCNICA DE INVESTIGAÇÃO9344784  aATHANASOPOULOSbDemos9358521  aDALEbAdam9358522  aSORRENTINObEric9358523  xOferta  104PJCD_258_00000000000000052022-06-066PJCD2589427344aPJcPJfPJ1CD258_4kPJCD258n2022-06-06o0rMOxOferta