How long after waterproofing a deck can you still isolate an ignitable liquid?

Dried, treated wood was sealed with Thompson's WaterSeal "Clear Multi-Surface Waterproofer" and exposed to outdoor, summer conditions. Sections of the sealed wood were then periodically tested and analyzed in accordance with ASTM methods. The WaterSeal contained a medium petroleum distillate (MPD) as a solvent for a wax. The treated lumber contained a background of aldehydes that could mimic a dearomatized MPD if not carefully investigated by the analyst. The MPD of the WaterSeal was detectable 14 days, but not 27 days after application with exposure to relatively hot, dry and sunny weather conditions. The test was repeated with the MPD detectable 16 days, but not 20 days after application with exposure to cooler and wetter weather conditions. The testing demonstrates the need for a thorough and complete investigation by the fire investigator and the submission of comparison samples to the laboratory.     

Development and evaluation of a standard method for the quantitative determination of elements in float glass samples by LA-ICP-MS

Forensic analysis of glass samples was performed in different laboratories within the NITE-CRIME (Natural Isotopes and Trace Elements in Criminalistics and Environmental Forensics) European Network, using a variety of Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) systems. The main objective of the interlaboratory tests was to cross-validate the different combinations of laser ablation systems with different ICP-MS instruments. A first study using widely available samples, such as the NIST SRM 610 and NIST SRM 612 reference glasses, led to deviations in the determined concentrations for trace elements amongst the laboratories up to 60%. Extensive discussion among the laboratories and the production of new glass reference standards (FGS 1 and FGS 2) established an improved analytical protocol, which was tested on a well-characterized float glass sample (FG 10-1 from the BKA Wiesbaden collection). Subsequently, interlaboratory tests produced improved results for nearly all elements with a deviation of < 10%, demonstrating that LA-ICP-MS can deliver absolute quantitative measurements on major, minor and trace elements in float glass samples for forensic and other purposes.     

An ideal material for the preparation of known toolmark test impressions

Traditionally, toolmark test exemplars are produced by applying a tool's working surface to a piece of soft metal such as lead. Soft, pliable metals are primarily used for this purpose because they will replicate the microscopic grooves present on a tool's working surface without damaging the tool. In this paper the authors present an alternative material for the preparation of test toolmarks. Jewelry modeling or carving waxes are utilized in this study. These waxes are designed for the jewelry modeling industry to create very fine, highly detailed wax models of jewelry pieces that will be cast in various metals utilizing the lost wax casting method. Jeweler's waxes have been found to be ideal for preparing test toolmarks from exemplar tools. The test tool's working surface is applied to a piece of the appropriate wax in a manner consistent with the tool's design. The replicas obtained are exact, highly detailed, 1:1, negative impressions of the exemplar tools working surface, have a long shelf-life, and are suitable for use in toolmark examination and comparison cases.     

Forensic value of pattern and particle transfers from deployed automotive airbag contact

Many automobile manufacturers began installing airbags on the driver's side in the late 1980's. Passenger side airbags followed in the early 1990's. Most airbags use a solid-propellant type of material that produces a hot gas to inflate the airbags. The gas in the driver side airbag leaves the inflator at a temperature as hot as 600 degrees C. The hot gas escapes through the vent holes after deployment, but it can also leak through the stitching seams in the front and singe a pattern on the occupant's clothing characteristic of the seam pattern. The singe patterns from the driver and passenger side airbags will be different. Cornstarch, which is used as a lubricant in some driver side airbags, can transfer to the driver's shirt. Hairs, fibers and make-up can transfer from the driver or passenger to the surface of the deployed airbags. Two cases are presented, illustrating singe patterns and particle transfers, and how they helped determine who a driver or passenger were.     

Assessment of edema fluid distribution in the brain

The technique is proposed allowing quantitation of brain edema and typing of liquor distribution in different parts of brain tissue. In combination with other assays this test can determine a variant of tanatogenesis, detect cause of death and duration of the terminal period. The method application is illustrated by the study of brain hydration in mechanical strangulation asphyxia. It is shown that this death is associated with hypohydration of cerebral structures, especially pronounced in the cortical compartments.     

Estimation of shooting distance for a pneumatic gun MP-654 K loaded with small lead shots

The experimental material has shown possibility of definition of shooting distance and some technical characteristics of the barrel of the pneumatic gun loaded with shots.