[Capabilities of using a multifunctional led device in the study of objects of forensic examination]

The purpose of the work is to determine the capabilities of the modern multifunctional device «Photobox 3138» with LED illuminators with a high color rendering index for photofixation, colorimetric, spectrozonal and multispectral analyzes of forensic objects. The competencies of the «Photobox 3138» device were experimentally revealed in terms of visualization and photofixation of both traces of biological origin (blood, sweat fat, saliva, etc.) and traces of traditional examinations, including shot products, oil products. The design of the device with a working field of 300×300 mm provides for the optimal arrangement of LED illuminators, including white light with a high color rendering index; spectrum-zonal illuminator with 4 types of LEDs with narrow non-intersecting spectral lines (458.1; 523.1; 594.1 and 630.6 nm) in the visible range of the spectrum; UV- (370 nm) and IR- (850 nm) illuminators. The fundamental possibility of using the resulting digital images of forensic objects for subsequent mathematical processing is experimentally shown. Images taken in different spectral ranges help to detect traces and damage. It was found that «Photobox 3138» allows you to solve a variety of diagnostic tasks related to the search, visualization, fixation and analysis of trace information.

Computer Vision in Analyzing the Propagation of a Gas-Gunpowder Jet

A method of mathematically processing the digital images of targets is developed. The theoretical and mathematical justification and the experimental validation of the possibility of estimating the amount of gunshot residue (GSR) and determining the GSR distribution over the target on the basis of its digital image is provided. The analysis of the optical density in selected concentric rings in the images reveals the radial dependence of soot distribution in the cross section of a gas-gunpowder jet. The analysis of the optical density in selected sectors of the circle reveals the angular dependence of the soot distribution in the gas-gunpowder jet cross section. It is shown that the integral optical density averaged over a selected area in the target image characterizes the mass of GSP deposited on it. It is possible to quantify the differences in the radial and angular distributions of the thickness of the GSR layer on various targets obtained both with the help of weapons of different types at the same distances and with the help of weapons of the same type at different distances, by calculating the distribution of optical density on their digital images.

[Possible use of carbon nanotubes as taggants in gunpowder for small firearms cartridges]

The purpose of the work is to study the possibility of using carbon nanotubes (CNT) as taggants in gun powder to provide expert differentiation of used small firearms cartridges; and to identify the main characteristics of the changes to carbon nanotubes under firing conditions, i.e. short-term exposure to high temperatures and pressures. The principal possibility of using carbon nanotube material for marking gunpowder in small firearms cartridges is stated. There is a need, in both the theory and practice of forensics, to develop such a labeling additive, one that is designed to analyze labeled cartridges and trace their use. We studied the effect of high temperatures and pressures (up to 3000-3500 ºC, 30 MPa) on the behavior of carbon nanotubes by using scanning electron microscopy. We found that the properties of carbon nanotube material - including high chemical and thermal resistance, low prevalence in nature, and a wide variety of forms and configurations - would help solve various investigative issues related to the circumstances of the use of small firearms, in particular, to determine the batch or sample of gunpowder used in the firing of a cartridge.

[The possibility of using the synthetic compound for the purpose of modeling of the human soft tissues in connection with the evaluation of gunshot damages]

The necessity of using a simulator of human soft tissues for the purpose of criminalistic and forensic medical expertises is dictated by the requirements put forward by the expert practice. The objective of the present study was to develop a synthetic simulator of the human soft tissues (compound) to ensure reliability of comparative criminalistics and forensic medical studies for the evaluation of gunshot injuries. The synthetic compound was prepared by mixing up the petroleum and/or synthetic oil with a polymeric thickening agent. This procedure was followed by heating the mixture at 90 degrees Celsius during 5 hours. Thereafter, petrolatum and/or ceresin and/or paraffin were added to the mixture. At the final stage, ionol was introduced, and the mixture was poured into a mold measuring 70×70×210 mm with its subsequent cooling down to 40 degrees Celsius during 10-12 hours. The experimental shooting was effected from the Kalashnikov AKS-74U assault rifle using the 5.45×39 mm (7H6) cartridges, Makarov pistol using the 9×18 mm cartridges and Nagant pistol using the CHELP-1000 cartridges. Five shots were fired from each of the three models. The experimental gunshot damages were evaluated visually by examining the inlet and exit openings and the bullet channel. In addition, criminalistic analysis of the grooves in cartridges was carried out. The technology for the fabrication of synthetic compounds based on ethylene, propylene, and butadiene co-polymers in the combination with such low molecular weight compounds as paraffins and ceresins having a homogeneous structure makes it possible to vary the rheological and mechanical properties of the simulators of human soft tissues for the solution of diagnostic and identification problems in the framework of criminalistics and forensic medical expertises.