The significance of ricochet marks in finding bullets at the shooting scene and in determining shooter location

2015 ◽  
Vol 287 ◽  
pp. 101-106
Author(s):  
Julia Mazur ◽  
◽  
Paweł Faliszewski ◽  

The article offers an overview of the ricochet phenomenon. The authors addresses the issue of examining bullet trajectories that have been deflected as a result of coming into contact with different types of obstacles. Ricochet marks are used by forensic experts to determine bullet trajectory, pattern, caliber and shooter location. Finding the ricocheted projectiles is difficult due to the fact that the angles of incidence (impact) and reflection are not equal. This article, devoted to ballistics and ricochet phenomenon, is based on the findings of the study conducted by specialists of the MWD Academy, Volgograd, Russia. The above study involved the use of a small semiautomatic 5.45 mm PSM pistol. Experimental firing was conducted with 5.45 mm pistol cartridges with central ignition (MPC); 2.5 g steel-core bullet; 0.15-0.17 g powder charge (Sf 040 gunpowder); muzzle velocity: 315–325 m/s. The shooting targets involved 16 mm particleboards (DSP) covered with laminate and without laminate, removed from old furniture. The results of 17 experimental firings are shown in this article. For all the firing trials, the muzzle was positioned at a distance of 2 m from the anticipated impact site. Based on the obtained results, it can be inferred that for all the ricochet incidents, the angle of reflection was greater than the angle of incidence. The projectile penetrated the particleboard over a certain distance and exited out the front site. The analysis of findings will in the future serve the formulation of the conclusions about the shooting scene, including finding the projectiles. The authors developed the following sequence of recommended expert activities: determining the type of projectile, trajectory, angles of incidence and reflection, shooter position and finally, the search for a projectile.

1968 ◽  
Vol 23 (2) ◽  
pp. 274-279 ◽  
Author(s):  
E. W. Becker ◽  
R. Klingelhöfer ◽  
H. Mayer

The reflection of a beam of nitrogen clusters from a polished stainless steel surface is investigated. The scattered flux shows a strong maximum at an angle of reflection almost 90°, independent of angle of incidence. The mean velocity of the reflected beam is about equal to the tangential velocity component of the incident beam. Measurements with increased background pressure demonstrate that the reflected beam still consists essentially of clusters.


2000 ◽  
Vol 78 (8) ◽  
pp. 747-754 ◽  
Author(s):  
W T Chyla

The general law of reflection concerns situations when the light ray undergoes a shift of frequency at the reflection point. For example, it governs reflection of light rays from a moving mirror (either in a vacuum or in a transparent medium), reflection from a motionless mirror coated with a layer of Raman-active molecules in the coherent-scattering regime, or external reflection of X-rays from the surface of a condensed matter sample, with partial dissipation of energy within the skin depth. The general law of reflection is derived from the extremum principle for propagation of variable-frequency light rays. It states that the angle of reflection depends not only on the angle of incidence but also on the frequency shift in the reflection point and dispersion of the refractive index of the medium in contact with the mirror. The compatibility of the general law of reflection and the special relativistic treatment of reflection is examined in detail. Applications of the new law of reflection are discussed in the special relativistic and the nonrelativistic regime. PACS Nos.: 42.15-i, 03.30+p


2015 ◽  
Vol 656-657 ◽  
pp. 468-472 ◽  
Author(s):  
Tadanori Sugino ◽  
Yasuo Yamane

Gloss of a metal surface is an important aspect for product quality evaluation. Evaluating the specular reflection is almost the same as evaluating the gloss. We propose a method that uses patterned area illumination to evaluate specular reflection. In specular reflection, the angle of incidence equals the angle of reflection. Consequently, when light (ray) of the area illumination, which has a striped pattern, are projected on a glossy metal surface, a striped pattern forms on the reflected image as a mirror-like reflection, and the sharpness of the striped pattern of the image provides information about the specular reflection on the surface. This characteristic is applied to a metal with a hairline surface finish. A hairline surface presents different glossiness at different viewpoints. When the direction of the striped pattern of illumination is changed, the sharpness of striped pattern on the reflected image varies owing to the surface roughness of the hairline finish. Therefore, we can evaluate the glossiness in various directions by rotating the pattern. The relationships between gloss evaluation value and surface roughness were indicated in our study. We tried the reproduction of the gloss evaluation by ray tracing to obtain the more detailed relationships between them. Ray tracing is a technique to generate an image in computer graphics. The approximate reproduction of gloss evaluation was obtained by the simulation.


2021 ◽  
Vol 59 (8) ◽  
pp. 650-651
Author(s):  
Shirish R. Pathare ◽  
Bhagyashri G. Latad ◽  
Rohan D. Lahane ◽  
Saurabhee S. Huli

2021 ◽  
pp. 138-138
Author(s):  
Abaci Boukera ◽  
Nebojsa Hristov ◽  
Ahmed Ziane ◽  
Damir Jerkovic ◽  
Slobodan Savic

This paper presents a numerical and an analytical approach for calculation of internal ballistics parameters through determination of thermal and gas- dynamic characteristics. The calculated parameters are validated through experimental tests on a real weapon system. The internal ballistic calculations are provided for two types of propellants using an analytical and a numerical model. Calculations and tests are performed for an anti-material rifle 12.7 mm. Weapon and ammunition testing is carried out according to the C.I.P. (Permanent International Commission) standard. Theoretical and experimental results for the gunpowder gases pressure and the muzzle velocity are compared. The good agreements between the calculated and the measured pressures and velocities increase the reliability of the estimated gunpowder gas temperatures in the barrel. The obtained results enable analysis and comparison of the output internal ballistics parameters for different types of propellant applications.


Transport ◽  
2013 ◽  
Vol 30 (2) ◽  
pp. 129-134 ◽  
Author(s):  
Gordana Kastratović ◽  
Nenad Vidanović

Paper explores some aspects of 3D modeling of ‘aircraft cable’ as mostly used sling wire rope. First, the 1×19 stainless steel core of ‘aircraft cable’ was investigated. The analysis was carried out by finite element method based computer program. The software used allowed two different types of contacts, including friction. The sling wire rope core was subjected to two different types of axial loading. The obtained results were compared with the solutions calculated from the literature (Costello 2012). Finally, using the advanced modeling techniques, the parametric 3D model of 7×19 ‘aircraft cable’ was analyzed using finite element method, in order to provide a better understanding and, hence, prediction, of the mechanical behavior of the sling wire ropes in lifting processes.


1987 ◽  
Vol 66 (8) ◽  
pp. 1350-1355 ◽  
Author(s):  
J.R. Kelly ◽  
W.A. Brantle

Biangular reflection photometry was correlated with quantitative stereology and direct pit-depth measurements for an electrolytically etched nickel-chromium-beryllium alloy. Effects of viewing angle, viewing aperture, and plane polarization of incident and viewing light were also studied. The results showed that architectural changes in the etched metal surface could be quantitatively described with the use of reflection photometry. An off-specular peak, located at an angle of reflection considerably different from the angle of incidence, was observed to have an intensity comparable with that of the specular reflection peak. Viewing aperture was found to affect one's ability to distinguish among degrees of surface roughness.


2017 ◽  
Vol 749 ◽  
pp. 251-256 ◽  
Author(s):  
Tadanori Sugino ◽  
Yuki Tashiro ◽  
Yasuo Yamane

The gloss of a metal surface is an important aspect for product quality evaluation. In general, gloss is influenced by specular reflection of light on a metal surface. Therefore, evaluating the specular reflection is almost the same as evaluating the gloss. We propose a method that uses patterned area illumination to evaluate specular reflection. In specular reflection, the angle of incidence equals the angle of reflection. Consequently, when light (ray) of the area illumination, which has a striped pattern, are projected on a glossy metal surface, a striped pattern forms on the reflected image as a mirror-like reflection, and the sharpness of the striped pattern of the image provides information about the specular reflection on the surface. This characteristic is applied to a metal with a hairline surface finish. A hairline surface presents different glossiness at different viewpoints. When the direction of the striped pattern of illumination is changed, the sharpness of striped pattern on the reflected image varies owing to the surface roughness of the hairline finish. Therefore, we can evaluate the glossiness in various directions by rotating the pattern. The rough relationships between gloss evaluation value and surface roughness were indicated in our study. In order to make the relationship between gloss evaluation and surface roughness for the estimation of surface roughness, we had tried the comparison for the gloss evaluation value and the surface roughness. The more precise relationship for seven directions on hairline-finished metal surface was measured. This report describes the results and considers the possibility of estimation of surface roughness by the gloss evaluation value.


2009 ◽  
Vol 407-408 ◽  
pp. 723-726 ◽  
Author(s):  
Tadanori Sugino ◽  
Yumi Satozono ◽  
Yasuo Yamane

Gloss evaluation of a metal surface is important for the quality as the product. In general, gloss of a metal surface is influenced by specular reflection of light on the surface. Therefore to evaluate the specular reflection is almost the same as the evaluation of the gloss. We propose the method to evaluate the specular reflection using patterned area illumination. In the specular reflection, the angle of incidence is equal to the angle of reflection. Consequently when lights (rays) of the area illumination which has a stripe pattern are projected to a glossy metal surface, the stripe pattern occurs on the reflection image by the mirror-like reflection and the sharpness of the stripe pattern of the image has information of the specular reflection on the surface. This character is applied for the metal surface with hairline. The metal surface with hairline has different gloss feeling at different point of view. When the direction of the stripe pattern of the illumination is changed, the sharpness of stripe pattern on the reflection image varies owing to the surface roughness of hairline. Therefore we can evaluate the glossiness for various directions by rotating the stripe pattern. This paper shows the availability of the proposed method through the experiment.


Sign in / Sign up

Export Citation Format

Share Document