Speaker Presentation Abstracts, Part 2
“EXCELIBR”: An Excel Spreadsheet for Solving the Optical Orientation of Uniaxial and Biaxial Crystals
C.J. Steven and M.E. Gunter — Geological Sciences, University of Idaho
The polarized light microscope remains the single most useful tool in identifying minerals. Using a spindle stage, the microscopist can orient a crystal’s principle refractive index (RI) vectors with the polarizer. Finding the principle RI vectors is accomplished by using either conoscopic methods, or more simply, using extinction data as inputs in the program EXCALIBR. The use of EXCALIBR has major advantages over conoscopic methods, but it is hindered by interface and compatibility issues. Presented here is a Microsoft Excel spreadsheet, which the authors have named “EXCELIBR,” which performs operations similar to EXCALIBR, including solving for the optical orientation of biaxial or uniaxial minerals using extinction data. With Excel as the interface, EXCELIBR is more accessible, familiar, and versatile for the user. This spreadsheet is useful for preliminary screening of a crystal for X-ray studies, optical characterization of minerals, and rapid mineral identification. Included with the crystal orienting calculations are tabs for double variation, RI modeling, and compensator plate calculations.
Investigation of Malaysia Airlines Flight MH17
Peter Zoon and Erwin Vermeij — Netherlands Forensic Institute
In the afternoon of July 17, 2014, Malaysia Airlines flight MH17 from Amsterdam to Kuala Lumpur crashed near Hrabove in eastern Ukraine. All 298 passengers and crew were killed. Initial reports hint at a non-accidental cause of the crash. At the time of the crash, an armed conflict between Ukrainian military and armed pro-Russia forces was taking place, which prevented the possibility of investigating at the crash site. Human remains and wreckage parts were eventually returned to the Netherlands.
On July 23, 2014, the disaster victim identification (DVI) process started at the Cpl. Van Oudheusden barracks in Hilversum. A forensic triage was set up within the DVI process to obtain forensic evidence. Mobile CT scanning, X-ray scanning, and handheld X-ray scanning were used in this triage to identify fragments from the wreckage. In December 2014, wreckage parts arrived in the Netherlands and a similar forensic triage was established.
Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) analysis of the fragments in combination with a focused ion beam (FIB) setup to create in-situ surface cross-sections were successful in identifying the origin of the fragments. Laser ablation ICPMS analysis yielded quantitative elemental compositions of the recovered fragments and the relationship between the fragments from the human remains and the wreckage parts.