Metallic Projectile Research Articles

Musculoskeletal pellet gun injuries; report from a conflict zone

<p class="abstract"><strong>Background:</strong> <span lang="EN-IN">Pellet gun used by law enforcement agencies have the potential to cause grevious or life threatening injuries as metallic projectiles fired at high speeds from pellet gun have potential to damage strongest structure like bone.</span>The objective of the study was t<span lang="EN-IN">o evaluate musculoskeletal pellet gun injuries in patients.</span></p><p class="abstract"><strong>Methods:</strong> <span lang="EN-IN">This study was conducted over two years involving 88 patients</span>.<strong></strong></p><p class="abstract"><strong>Results:</strong> <span lang="EN-IN">A significant number of patients had grevious musculoskeletal pellet gun injuries. 50 patients had superficial injuries, 11 patients had fractures, 5 had nerve injuries, 7 had tendon injuries and 15 had intra-articular pellets. </span></p><p class="abstract"><strong>Conclusions:</strong> <span lang="EN-IN">Pellet guns can cause grevious musculoskeletal injuries which can leave the victim with lifelong disability.</span></p>

Carbon-bearing phases in shock-induced melt zones of the Elga meteorite

The mineralogy and texture of shock-induced melt veinlets and melt pockets in silicate inclusions in the Elga IIE iron meteorite have been studied by reflected-light optical microscopy, EMPA, SEM, Raman spectroscopy and TEM. The results suggest that Elga experienced two discrete impact events. The earlier event involved the collision of a metallic projectile with a silicate target and resulted in partial melting and recrystallization of the silicate material, forming schreibersite and oxide rims between the metal and silicate. The later impact event resulted in melt pockets in the silicate inclusions and was associated with fragmentation, melting, and brecciation of the rims and displacement of some fragments into the melt pockets. These fragments are shown to contain carbon-bearing phases: siderite and amorphous sp2 carbon, which form carbon–oxide, siderite–oxide, and siderite–schreibersite associations. The fact that the carbon-bearing fragments are spatially constrained to shock breccia and melt zones indicates that these fragments are genetically related to the impact process and that their carbon-bearing phases are of cosmic origin.

Micro-structure response and fracture mechanisms of C/SiC composites subjected to low-velocity ballistic penetration

Dynamic response and fracture mechanisms of Carbon Fiber Reinforced Silicon Carbide Composites (C/SiC) especially during low-velocity ballistic penetration are studied both experimentally and numerically. The gas-gun facility is used to fire spherical metallic projectile for striking velocity of 150ms−1 on the target panels, and the impact phenomenon is captured through high-speed photography. A micro-structure based approach is employed to model C/SiC target in this paper. This proposed numerical technique captured the mechanical response (residual energy, expansion process and velocity of debris cloud, fracture morphology and mode) of target, with adequate accuracy. The fracture modes involve void collapse, delamination, fiber bundle splitting and breakage. The debris cloud possesses two types of constituents, classified by fragments' volume and high-energy powdering column at the front. The experimental and calculated results emphasize that the impact velocity, projectile shape and hardness have significant influence on the mechanical behavior of C/SiC composites, including fragment size, fracture surface morphology, fracture mode and mechanism.

Fragmentation of Millimeter-Size Hypervelocity Projectiles on Combined Mesh-Plate Bumpers

This numerical study evaluates the concept of a combined mesh-plate bumper as a shielding system protecting unmanned spacecraft from small (1 mm) orbital debris impacts. Two-component bumpers consisting of an external layer of woven mesh (aluminum or steel) directly applied to a surface of the aluminum plate are considered. Results of numerical modeling with a projectile velocity of 7 km/s indicate that, in comparison to the steel mesh-combined bumper, the combination of aluminum mesh and aluminum plate provides better fragmentation of small hypervelocity projectiles. At the same time, none of the combined mesh/plate bumpers provide a significant increase of ballistic properties as compared to an aluminum plate bumper. This indicates that the positive results reported in the literature for bumpers with metallic meshes and large projectiles are not scalable down to millimeter-sized particles. Based on this investigation’s results, a possible modification of the combined mesh/plate bumper is proposed for the future study.

Molecular Dynamics Study of Damage of Materials by Collision of High Speed Metallic Projectile

Molecular Dynamics Study of Damage of Materials by Collision of High Speed Metallic Projectile

Forensic examination after exhumation: Contribution and difficulties after more than thirty years of burial

We report a case of a Tunisian footballer who was found dead abroad under suspicious circumstances. The cause of death was, originally, attributed to a lightning strike. The corpse was buried without/autopsy. Over thirty years later, the family requested the exhumation to verify the identity and the cause of death. The exhumation was performed in 2011. DNA profiling from teeth and femur bone samples confirmed the identity of the deceased. The dry bone study revealed defects in the skull and the pelvis evoking firearm injuries. Post-mortem CT with three-dimensional (3-D) reconstruction allowed to confirm the characteristics of firearms injuries and to speculate about the number and the trajectories of potential shots. Nevertheless, the vitality of these injuries as well as the eventual fatal shot and the shooting distance could not be determined. Likewise, the type of the eventual weapon could not be clarified as there were no bullets or any metallic projectile fragments. Despite all doubts, the forensic explorations have allowed to verify the identity of the deceased, to evoke firearms injuries and, mainly, to deny the proposed cause of death after more than thirty years of burial. Moreover, the loss of soft tissues and bone fragility were the major obstacles.

Survivability of copper projectiles during hypervelocity impacts in porous ice: A laboratory investigation of the survivability of projectiles impacting comets or other bodies

During hypervelocity impact (>a few kms−1) the resulting cratering and/or disruption of the target body often outweighs interest on the outcome of the projectile material, with the majority of projectiles assumed to be vaporised. However, on Earth, fragments, often metallic, have been recovered from impact sites, meaning that metallic projectile fragments may survive a hypervelocity impact and still exist within the wall, floor and/or ejecta of the impact crater post-impact. The discovery of the remnant impactor composition within the craters of asteroids, planets and comets could provide further information regarding the impact history of a body. Accordingly, we study in the laboratory the survivability of 1 and 2mm diameter copper projectiles fired onto ice at speeds between 1.00 and 7.05kms−1. The projectile was recovered intact at speeds up to 1.50kms−1, with no ductile deformation, but some surface pitting was observed. At 2.39kms−1, the projectile showed increasing ductile deformation and broke into two parts. Above velocities of 2.60kms−1 increasing numbers of projectile fragments were identified post impact, with the mean size of the fragments decreasing with increasing impact velocity. The decrease in size also corresponds with an increase in the number of projectile fragments recovered, as with increasing shock pressure the projectile material is more intensely disrupted, producing smaller and more numerous fragments. The damage to the projectile is divided into four classes with increasing speed and shock pressure: (1) minimal damage, (2) ductile deformation, start of break up, (3) increasing fragmentation, and (4) complete fragmentation. The implications of such behaviour is considered for specific examples of impacts of metallic impactors onto Solar System bodies, including LCROSS impacting the Moon, iron meteorites onto Mars and NASA’s “Deep Impact” mission where a spacecraft impacted a comet.

Metal projectile injuries in cats: review of 65 cases (2012-2014).

The objective of this study was to compare the prevalence of different types of injuries caused by various types of projectiles among urban, suburban and rural cats of different ages in order to predict the type of injury sustained. For the period 1 January 2012 to 30 April 2014, the medical records of cats with metal projectile injuries (PIs) were searched from the archive of the university's small animal diagnostic imaging centre. Age, sex, owner address, admission during a weekend or on a working day, month of admission, projectile position (head and neck; thoracic region; abdominal region, including lumbosacral spine; forelimbs; and hindlimbs, including tail), number of projectiles, presence of a wound and fracture related to the projectile, and the type of projectile were recorded for each cat. Sixty-five cats with PIs were admitted during the defined period. In 38.5% of cats the projectiles found upon radiography were incidental findings. The frequency of PIs peaked in March. Airgun projectiles were found in 80.0% of the cats. PIs in two or more body regions were found in 29.2% of the cats. Among the cats that had only been shot in one body region, the projectile was most frequently found in the abdominal region, including the lumbosacral spine (41.3%). These results might prompt clinicians to evaluate closely and screen for feline PIs in emergency situations.

Chemical and isotopic characterization of products of small-scale hypervelocity impacts: the Gebel Kamil event

This study presents chemical and oxygen isotope data on a series of materials found in the area of the Gebel Kamil crater, a recent well preserved impact crater in southern Egypt, which was formed by the explosive impact of a metal projectile. Intracrateric target rocks, fallback deposits, impact vitreous ejecta (impactite) and recent or present-day aeolian sands have been analysed. Exposed crater wall rocks essentially consist of quartz arenites with minor siltstone beds chemically and isotopically quite distinct, the latter resulting enriched in lithophile elements (Al, K, Ba, Y, REE, etc.) and 18 O. Abundance of siderophile elements (Ni, Co, Cu) indicates that none of the exposed target rocks and recent aeolian sand deposits was contaminated by materials of the metal impactor. On the other hand, a projectile-derived component was found in all samples of fallback deposits and in impact melt ejecta. Lithophile element and isotope chemistry of the fallback deposit results intermediate between that of quartz arenite and silstone target rocks. White- light-coloured glassy ejecta representing a minor (< 10% vol.) component of the impact melted products are chemically and isotopically distinct from dark-coloured vitreous clasts. The latter are enriched in lithophile elements and also 18 O with respect to estimated “average” composition of the intracrateric target rocks. The presence of a projectile component in all samples of vitreous ejecta clasts suggests that melting of terrestrial material becomes extensive only when the projectile is directly involved in melting. The extreme variability of siderophile element ratios (e.g. Ni/Co, Ni/Cu) in materials (i.e., fallback deposits and vitreous ejecta) contaminated by projectile components suggests that significant element fractionation occurs during the explosive disruption of an impactor. A distinctive chemical and isotope signature of most of the impact melted products (i.e., dark vitreous ejecta), with respect to “average” composition of the exposed crater

Effect of Pre-Existing Defects on Fracture of Electromagnetically Accelerated Projectiles: Comparison of Simulations and Experiments

Abstract Induction coil gun uses electromagnetic forces to accelerate metallic tubular projectiles for impact studies. It consists of a helical coil and a cylindrical projectile placed coaxially with the coil. Electromagnetic flux linkage between the coil and the projectile sets up axial and radial forces on the projectile. The axial force accelerates the projectile out of the coil, while the radial force leads to pinching . In certain experiments, projectiles are non-uniformly pinched and undergo plastic buckling. This is manifested in longitudinal cracks that degrade system efficiency. These cracks cannot be handled in a R-Z axisymmetric model. Hence we have developed a composite model consisting of MHD R-Z (axisymmetric) and 2D-Hydrodynamic X-Y (plane geometry) models to study deformation and longitudinal cracking. Our study predicts that an initial perturbation in projectile thickness along the θ direction can grow and lead to localization of plastic strains causing longitudinal cracking.

Effects of Specimen Size and Boundary Conditions on the Penetration Depth of Metal Ceramic Structure

Ceramics has high hardness but low density and has been used in defense to enhance the protection of human bodies or vehicles against projectile penetration. Ceramics can defeat a ballistic threat by deforming and fracturing a metal projectile, thus eliminate or reduce the depth of penetration in backing steel. This study investigates the penetration progress of a tungsten alloy projectile into an Al2O3 ceramics (alumina) backed with high strength steel 4340. Depth of penetration tests were conducted on ceramics/steel specimens by WNiFe projectiles at impact speeds around 1280m/s. Numerical simulations corresponding to the test configurations were carried out using commercial software (Autodyn) and the prediction of crater profile coincides with experimental results. Further simulations investigated the effects of specimen size and boundary conditions on the total depth of penetration; the performance of metal ceramic structure against ballistic penetration was explored and evaluated.

Fractografía y disipación de energía cinética en un panel balístico de cerámica/polímero sometido al impacto de un proyectil metálico

En este trabajo se exploró el comportamiento y los mecanismos de daño de un panel laminado compuesto a partir de materiales poliméricos y cerámicos, ante el impacto de un proyectil metálico. Se realizó el diseño de un sistema con la cara de impacto en material cerámico (SiC), con respaldo elaborado en polietileno de peso molecular ultra alto (UHMWPE), placas elaboradas con geometría cuadrada de 200 mm de lado y 5 mm de espesor, y cortes de tejido polimérico con iguales dimensiones de área. Se tomó como referencia el montaje de la norma (NIJ) Standard 0101.06 para el ensayo a impacto balístico; en el material cerámico se identificó la formación de cráter, fracturas y delaminación como mecanismos de falla predominantes, utilizando microscopia óptica y de barrido; en el material polimérico se observó fibrilación, torsión, fusión de fibras, delaminación y deformación cónica y posteriormente se analizaron las muestras empleando los modelos de balance de energía cinética de "Morye, Smith y de Retch e Ipson". El resultado evidenció que el arreglo con mayor influencia para disipar energía, es el panel elaborado con doble placa cerámica (SiC) y doble capa de tejido polimérico como respaldo.

Experimental characterization of light emission during shock-driven cavity collapse

The authors describe experimental work examining the collapse of a cavity by a strong shockwave. A millimeter size cavity is cast in Phytagel, which is then impacted by a metallic projectile accelerated by a compressed gas gun, reaching velocities up to 500 m/s. The impact generates a strong shockwave that propagates into the gel at greater than sonic velocity. Schlieren images are presented that illustrate both this process and the subsequent cavity collapse at a sub-microsecond timescale. As the shockwave reaches the cavity, it is shown to cause a rapid asymmetric collapse process characterized by the formation of a high-speed transverse jet. The pressure of the shockwave is found to be 100+ MPa as measured via a custom-built fiber-optic probe hydrophone. Previous work examining shock-driven cavity collapse observed luminescence, postulated to be due to the high-speed impact of the transverse jet on the far bubble wall; this experimental observation is replicated. Further, the light emission is characterized as a function of impact velocity and thus of shockwave pressure. This reveals that shock-driven cavity collapse shares many of the unique features that make the more widely studied SBSL-type collapse interesting.

Fourth-Year Medical Student Opinions and Basic Knowledge Regarding the Field of Radiology

This study evaluates the opinions and knowledge of fourth-year US medical students regarding radiology and analyzes the influence of a required or nonrequired radiology rotation as a reflection of the effectiveness of radiology medical student education. Our institutional review board granted exempt status. An invitation e-mail was sent to 137 US medical schools. Upon receiving approval a second email was sent containing our voluntary anonymous online survey hyperlink to forward to their fourth-year class. Survey topics included demographics, radiology educational experiences, attitudes toward the field, and basic radiology knowledge. Responses were collected between August 4 and September 26, 2011. A total of 444 fourth-year medical students from 37 medical schools participated: 89% planned to enter a nonradiology specialty, 10.8% were required to take a dedicated radiology rotation, 34.9% completed one, 77% planned to complete one by graduation, 88.4% thought radiology often changes patient care or is at least as important as physical exam, 91.4% underestimated the cancer risk of an abdomen and pelvis computed tomography by at least one order of magnitude, and 72.9% by at least two orders. Seventy-seven percent had never heard of the American College of Radiology (ACR) Appropriateness Criteria. Respondents underestimated the potential risks of magnetic resonance imaging (MRI); with 58.3% aware intravenous gadolinium can cause nephrogenic systemic fibrosis and 79.4% aware of potential injury from metallic projectiles. 40.4% indicated that non-radiologist clinicians in specific medical specialties interpret their respective imaging studies at least as accurately as corresponding subspecialty radiologists. Other results include student opinions regarding teleradiology, radiologist lifestyle, and compensation. Fourth-year medical students recognize the importance of radiology but are poorly informed regarding radiation safety, MRI safety, and ACR Appropriateness Criteria, despite 34.9% having a dedicated rotation. This highlights the need for adoption of the Alliance of Medical Student Educators in Radiology curriculum.

Air gun injury with deadly aftermath – Case report

In Republic of Macedonia the use of air guns is quite widespread. They are used mainly for target practice. They are regulated by the Law of Arms, where they are defined as pneumatic weapons. There is no legal limit on type or quantity of ammunition that one may possess. Our Institute performs at least 90% of the forensic autopsies in Macedonia. In this report we describe the only fatality by pneumatic weapon to come to our attention over the past 10 years. A 6-year-old girl was accidentally wounded by her brother when he and his father were trying a new air gun, a 4.5mm single shot, break barrel, spring piston air rifle manufactured in China under the brand "Westlake". She died within minutes. Autopsy showed cardiac tamponade due to penetration of the aorta. A 0.5g metal projectile, 4.5mm in diameter, with a pointed, conical shape, was recovered from the pericardial sac.

New Method for Projectile Velocity Measurement Using Faraday-Type Electromagnetic Sensor for Hypervelocity Impact Experiments and Detection Efficiency of the Method

The authors developed a Faraday-type electromagnetic sensor as a conventional and fiducial technique for measuring the velocities of projectiles accelerated by propellant and gas guns. The sensor consists of a doughnut-shaped ferrite magnet and a pick-up coil, and detects the disturbance of the magnetic field in the pick-up coil caused by the passage of a metallic projectile. Projectile velocity is estimated from the time interval between two electromotive force signals and the distance between two sensors. Firing tests using a small nonmagnetic spherical Al projectile show that the projectile velocity is obtained with an accuracy of less than 2% in the velocity range from 2.17 to 5.80 km/s.

New Method for Projectile Velocity Measurement Using Faraday-Type Electromagnetic Sensor for Hypervelocity Impact Experiments and Detection Efficiency of the Method

The authors developed a Faraday-type electromagnetic sensor as a conventional and fiducial technique for measuring the velocities of projectiles accelerated by propellant and gas guns. The sensor consists of a doughnut-shaped ferrite magnet and a pick-up coil, and detects the disturbance of the magnetic field in the pick-up coil caused by the passage of a metallic projectile. Projectile velocity is estimated from the time interval between two electromotive force signals and the distance between two sensors. Firing tests using a small nonmagnetic spherical Al projectile show that the projectile velocity is obtained with an accuracy of less than 2% in the velocity range from 2.17 to 5.80 km/s.

Cavitation in impacted drops and jets and the effect on erosion damage thresholds

It is well known that metals and alloys erode at lower impact threshold velocities than expected. This was studied by Thomas and Brunton (1970) [1] who reported “discrepancy factors” in the range 4–10. These authors suggested that liquid impact was a more searching impact than solid impact since it was able to exploit weaknesses in the metal. Further, as erosion develops the sideways liquid flow can add shear stresses to surface steps and hydraulically load liquid trapped in cracks and crevices. In 1970, Brunton and Camus [2,3] showed that during the impact process cavities could form inside the liquid drops, and that some collapsed onto the solid surface. This provided a second potential mechanism to explain the low damage threshold with the cavity collapse adding to the “water hammer” pressures. However, Brunton and Camus were cautious in offering this as a potential mechanism. In this paper, we argue that the Brunton and Camus experiments were in a relatively low velocity regime (20–70ms−1), compared with those in turbine erosion and rain erosion of aircraft components. This paper presents high-speed photographic sequences of cavity formation and shock propagation in impacted liquids using a range of techniques. Finally, a new method is described in which a metal projectile is fired at a liquid jet. This produces large amounts of cavitation. Our conclusion is that the cavity collapse process can explain the observed lower threshold velocities.

Removal of a Low-Velocity Projectile From the Base of the Sphenoid Sinus Using Navigation-Guided Endoscopy

A patient surviving after a metal projectile penetrates the sphenoid sinus is unusual. Removing a foreign object from this region is challenging because of the difficult access and proximity to delicate structures. The use of navigation-guided endoscopy makes the manipulation of the surgical instruments near delicate structures safer, and the procedure is minimally invasive. A computed tomographic scan of brain showed the projectile located at the base of the left sphenoid sinus. To prevent infection and irritation and avoid secondary surgical damage, navigation-guided endoscopy was used to remove the bullet. Using the BRAINLAB navigation system, the movement of the endoscope could be followed on the screen, and the tip could be navigated into close contact with the projectile. The bullet could be located, without being visible through the endoscope, making the incision and removal of the bony wall of the sinus minimal; it was removed without complications. Intraoperative navigation of endoscopes is very useful because it enables the surgeon to correlate the visual information through the endoscope with the localization of the instruments seen on the navigation screen. Patient safety and reinforced self-confidence of surgeons are advantages of this procedure. Reduced operative time may not always occur because of a lack of experience with the navigation system. When there are no vascular or neurologic complications, a minimally invasive treatment using nasal navigation-guided endoscopic removal can limit the potential surgical damage.

Diagnostic challenges and treatment options of a suspected pericardial metallic projectile foreign body in a dog

To describe a case of a suspected pericardial metallic projectile foreign body in a dog with a history of trauma to the left shoulder and to review the literature regarding the management of cardiac and intracardiac foreign bodies. A 3-year-old male, neutered Brittany spaniel presented with a 10-day history of decreased activity and partial anorexia. Serial thoracic radiographs identified a migrating pericardial metallic projectile foreign body and an echocardiogram diagnosed pericardial effusion and abdominal ultrasound identified the presence of ascites. Concern for a possible effusive-constrictive pericarditis prompted a subphrenic pericardectomy performed via thoracoscopy. The foreign body was not recovered. Six months postsurgery, the dog remained asymptomatic. Considering the high rate of complications that develop in human patients where the foreign bodies are not removed, veterinarians should be aware of risks associated with long standing pericardial foreign bodies even when no clinical signs are present. Guidelines from the human literature may be considered for investigation of, and treatment options for, cardiac and intracardiac metallic projectile foreign bodies in dogs.