Roentgenoscopy of laser-induced projectile impact testing.

Laser-induced projectile impact testing (LIPIT) based on synchrotron imaging is proposed and validated. This emerging high-velocity, high-strain microscale dynamic loading technique offers a unique perspective on the strain and energy dissipation behavior of materials subjected to high-speed microscale single-particle impacts. When combined with synchrotron radiation imaging techniques, LIPIT allows for in situ observation of particle infiltration. Two validation experiments were carried out, demonstrating the potential of LIPIT in the roentgenoscopy of the dynamic properties of various materials. With a spatial resolution of 10 µm and a temporal resolution of 33.4 µs, the system was successfully realized at the Beijing Synchrotron Radiation Facility 3W1 beamline. This innovative approach opens up new avenues for studying the dynamic properties of materials in situ.

Wandering projectile, a rare cause of acute urinary retention.

BACKGROUND: Urethral obstruction due to retained projectile migrating into the genitourinary system has rarely been reported. The literature describes two main methods of retained projectile removal from the genitourinary system: (1) spontaneous expulsion during voiding and (2) manual extraction due to urethral obstruction causing acute urinary retention. CLINICAL PRESENTATION: We present a case in which a 23-year-old man presented with acute urinary retention four days after suffering a gunshot wound to the right distal posterolateral thigh. A retained projectile eroded through the posterior wall (slightly to the right) of the bulbar urethra at the bulb, migrated through the urethra, and eventually became lodged in the external urethral meatus, causing obstruction and acute urinary retention. Subsequently, the foreign body was removed with manual extraction along with gentle external pressure under sedation and the patient was discharged with a 16 Fr transurethral catheter in situ to be kept for 1 week and removed after a week. CONCLUSION: The absences of signs do not always effectively rule out urethral or bladder injury. Urethral foreign bodies are not commonly encountered when they do the entry is usually the urethral meatus. However, the treating physician must that other mechanisms also exist especially in those with bullet injury to flank, abdomen, pelvis and even the distal thigh like our case.

LSTM-Based Projectile Trajectory Estimation in a GNSS-Denied Environment.

This paper presents a deep learning approach to estimate a projectile trajectory in a GNSS-denied environment. For this purpose, Long-Short-Term-Memories (LSTMs) are trained on projectile fire simulations. The network inputs are the embedded Inertial Measurement Unit (IMU) data, the magnetic field reference, flight parameters specific to the projectile and a time vector. This paper focuses on the influence of LSTM input data pre-processing, i.e., normalization and navigation frame rotation, leading to rescale 3D projectile data over similar variation ranges. In addition, the effect of the sensor error model on the estimation accuracy is analyzed. LSTM estimates are compared to a classical Dead-Reckoning algorithm, and the estimation accuracy is evaluated via multiple error criteria and the position errors at the impact point. Results, presented for a finned projectile, clearly show the Artificial Intelligence (AI) contribution, especially for the projectile position and velocity estimations. Indeed, the LSTM estimation errors are reduced compared to a classical navigation algorithm as well as to GNSS-guided finned projectiles.

Simulation and Experimental Verification of Magnetic Field Diffusion at the Launch Load during Electromagnetic Launch.

The unique magnetic field environment during electromagnetic launch imposes higher requirements on the design and protection of the internal electronic system within the launch load. This low-frequency, Tesla-level extreme magnetic field environment is fundamentally distinct from the Earth's geomagnetic field. The excessive change rate of magnetic flux can readily induce voltage within the circuit, thus disrupting the normal operation of intelligent microchips. Existing simulation methods primarily focus on the physical environments of rails and armatures, making it challenging to precisely compute the magnetic field environment at the load's location. In this paper, we propose a computational rail model based on the magneto-mechanical coupling model of a railgun. This model accounts for the dynamic current distribution during the launch process and simulates the magnetic flux density distribution at the load location. To validate the model's accuracy, three-axis magnetic sensors were placed in front of the armature, and the dynamic magnetic field distribution during the launch process was obtained using the projectile-borne-storage testing method. The results indicate that compared to the previous literature methods, the approach proposed in this paper achieves higher accuracy and is closer to experimental results, providing valuable support for the design and optimization of the launch load.

A scanning electron microscopy study of projectile entry fractures in cortical bone; genesis and microarchitectural features.

The present paper presents a scanning electron microscope (SEM) analysis of the genesis and microarchitecture of experimentally induced cortical entry fractures in porcine scapulae impacted at velocities ranging from 54 to 897 m/s. SEM observation was conducted on polyurethane replicas cast from negative silicone moulds. Analysis of the sequence of fracture processes operative during projectile impact revealed the presence of ring cracks at the site of impact, confirming that penetration in sandwich bones is achieved by cone crack propagation. Despite impulsive loading, two forms of plastic deformation were identified in the cortical bone surrounding the entry fracture up to a maximum velocity of 871 m/s. Microscopic radial and concentric cracks were associated with projectile impact, and the role of pores and pits as stress concentrators was captured. Possible underlying mechanisms for the observed plastic deformation are described, and the diagnostic utility of SEM analysis is presented.

Neurosurgery during the Greco-Italian War (World War II): the management of war-related head injuries at the Italian field hospital of Sinanaj in Albania.

During the Greco-Italian War (World War II [WWII], 1940-1941), an Italian field hospital was set up in Sinanaj, Albania. The hospital's military surgeons carefully collected information about the characteristics and management of patients with war-related injuries. In 1942, they published a detailed report, with a section dedicated to the management of war-related head injuries. The aim of this report is to analyze that section, to describe the characteristics and neurosurgical management of war-related head injuries, and to depict the status of war neurosurgery in the Royal Italian Army during WWII. The analysis revealed that, during the Greco-Italian War (November 1940-April 1941), 149 patients with war-related head injuries were admitted to the Sinanaj hospital, and 48 patients underwent surgery. Head injuries were caused by bomb fragments in 126 patients, bullets in 5 patients, and other causes (falls from height, vehicle accidents, or rock fragments) in 18 patients. Six patients (12.5%) died after surgery. Before surgery, patients underwent resuscitation with blood transfusions and fluid. Preoperatively, a plain head radiograph was usually acquired to locate metallic and bone fragments. The surgical technique consisted of craniotomy or craniectomy, aggressive debridement of metallic and bone fragments, and watertight dural closure. Surgical drainage, overall aseptic technique, serial spinal taps, and perioperative antibiotics were used to prevent infections. The surgical aims and technique used by the Italian surgeons for the management of head injuries were similar to those of the Allied surgeons during WWII. Operative mortality was also comparable. Although the surgical technique for war-related head injuries has evolved since WWII, many aspects of the technique used by the Italian and Allied surgeons during WWII are still in the standard of care today.

Sports ball projectile ocular trauma in dogs.

OBJECTIVE: To describe the clinical features, management, and outcome of dogs presenting with sports ball projectile ocular injuries. ANIMALS STUDIED: Eighteen dogs. PROCEDURES: A retrospective study reviewing cases of ocular injury due to a sports ball projectile that presented to the Cornell University ophthalmology service between 2004 and 2021. Dog age, type of sports ball, initial ocular lesions, eye affected, clinical management, and visual outcome were recorded. RESULTS: Sports ball projectile ocular injuries were identified in 18 eyes of 18 dogs. The median age of the dogs was 1.0 years old, ranging from 0.3- to 9-years- old. Nine dogs were male, and 9 were female. Ocular injuries were caused by small, dense balls (e.g., golf balls, baseballs) in 11 dogs; small, light balls (e.g., tennis balls, toy balls) in 5 dogs; and large, soft balls (e.g., soccer ball, football) in 2 dogs. Closed-globe injuries (12 of 18 eyes) presented with traumatic uveitis (91%), hyphema (45%), and subconjunctival hemorrhage (18%). All 12 closed-globe injury cases were medically managed, eight dogs remained visual. Open-globe injuries (6 of 18 dogs) presented with three corneal lacerations and three scleral ruptures. Five open-globe injuries required enucleation, and one was medically managed and maintained vision. CONCLUSION: Sports ball projectile ocular injuries in dogs can result in substantial ocular morbidity and in loss of vision. Small, dense balls were associated with injuries that carried the most guarded prognosis and required more aggressive management. Small and large lighter projectiles were associated with less serious ocular injuries and visual outcomes.

[Characteristics of the trajectory of projectiles after penetration of biological and non-biological obstacles in shots fired from various types of firearms]. / Kharakteristika traektorii dvizheniya snaryadov posle probitiya biologicheskikh i nebiologicheskikh pregrad pri vystrelakh iz razlichnykh obraztsov ognestrel'nogo oruzhiya.

The purpose of the work was to study the movement trajectory of the projectile after breaking through an obstacle made of various materials installed at various angles to the aiming line when firing from rifled and traumatic weapons. As a result of a series of experimental shots by shells fired from a traumatic pistol «Jorge¼ (9×22 mm RA cartridge with an initial velocity of 300±20 m/s and a bullet weight of 0.7 g) and the Blaser R93 carbine (Norma Jaktmatch 9.3×62 mm hunting cartridge with an initial speed of 765 m/s and a bullet weight of 11 g) it has been found that, when punching both biological simulators and triplex glass located at the angles of 40-60° with respect to the aiming line, a deflection of the firearm from the aiming line is observed.

Exploring variability in lithic armature discard in the archaeological record.

The invention of projectile technology had important ramifications for hominin evolution. However, the number of stone points that could have been used as projectiles fluctuates in archaeological assemblages, making it difficult to define when projectile technology was first widely adopted and how its usage changed over time. Here we use an agent-based model to simulate a hunter-gatherer foraging system where armatures are dropped according to their usage. We explore the impact of interactions between human behaviors and the environmental constraints of a data-informed landscape on the distribution and number of lithic armatures found in archaeological assemblages. We ran 2400 simulations modeling different population sizes, rates of hunting with projectiles, and tool curation levels. For each simulation, we recorded the location of dropped armatures and calculated the number and percentage of used armatures that were discarded at habitation camps vs. lost during hunting. We used linear regression to identify the demographic, behavioral, and environmental factor(s) that best explained changes in these numbers and percentages. The model results show that in a well-controlled environment, most armatures used as projectile weapons are lost or discarded at hunting sites; only ∼4.5% of used armatures (or ∼2 armatures per year of simulation) are discarded in habitation camps where they would likely be excavated. These findings suggest that even rare hafted armatures found in the Early and Middle Stone Age could indicate a well-established use of such tools. Our model shows that interactions between reoccupation of archaeological sites, population size, rate of hunting with projectile weapons, and tool curation levels strongly influence the count of lithic armatures found in archaeological assemblages. Therefore, we argue that fluctuations in the counts of armatures documented at archaeological sites should be evaluated within their demographic and environmental contexts to better understand if they reflect spatiotemporal changes in hunting behavior.

An arrow that missed the mark: a pediatric case report of remarkable neurologic improvement following penetrating spinal cord injury.

Penetrating spinal cord injuries are rare in children but result in devastating impacts on long-term morbidity and mortality-with little known about the recovery capacity in this age group. We present the case of an eight-year-old child who sustained a penetrating injury through the right anterior thorax. Thoracic CT showed the arrow tip extending through the spinal canal at T6. Neurologic examination revealed no motor or sensory function below T6. The arrow was surgically removed without complications through an anterior-only approach. MRI on post-operative day (POD) 4 showed focal T2 hyperintensity at the T6 spinal cord. Patient was discharged on POD33 with an American Spinal Injury Association (ASIA)-D score and trace voluntary control over bowel and bladder function. Remarkably, four months later, he had near normal bowel and bladder function, with near-intact lower extremity strength and self-sustained ambulation. Follow-up imaging revealed hemicord formation at the level of injury. We review our case of penetrating spinal cord injury in a child and similar reports in the literature. Penetrating thoracic spinal cord trauma portends poor clinical outcomes, particularly when employing available adult prognostic spinal cord injury scoring metrics. Incomplete spinal cord injury, and often-associated spinal shock, can mimic a complete injury-as in our patient, which improved to near-complete motor and sensory restoration of function and resulted in the formation of a split hemicord. This case represents a unique penetrating spinal cord injury with remarkable neurologic recovery, which would advocate against definitive early prognostication in the pediatric population.

Projectile vomiting and Valsalva-like abdominal contractions as an uncommon presentation of supraventricular tachycardia in an infant.

Paroxysmal supraventricular tachycardia (PSVT) is a prevalent pediatric arrhythmia. Neonatal and infantile-onset presentation is unspecific, thus making differential diagnosis essential in not delaying crucial intervention. We here describe the case of an undetected PSVT in an infant performing repeated abdominal contractions, thus presenting with projectile vomiting. At an early stage of tachycardia, infants are probably able to unconsciously attempt and succeed to terminate acute episodes by strengthening vagal stimulation in the form of Valsalva-like abdominal contractions, but only up to a point. As PSVT progresses, heart failure may develop. Early recognition and treatment are therefore required to minimize negative outcomes.

[Features of the trajectory of particles of car triplex glass damaged by Saiga carbine shots with the cartridge 5.45×39 mm]. / Osobennosti traektorii vybrosa chastits tripleksnogo stekla avtomobilya, povrezhdennogo vystrelami iz karabina «Saiga¼ pod patron 5,45×39 mm.

THE OBJECTIVE OF THE WORK: Is to study the character of deflection of fragments of a semi-jacketed shell (a semi-jacketed bimetallic bullet with a lead core of a 5.45×39 mm cartridge for the Saiga carbine) and the ejection of fragments of the triplex glass shot with it. The experiments results showed that when a triplex glass pierced at an angle of 60° with respect to the sightline, there is a deflection towards the normal line of the flight direction of the shell and obstacle fragments. The shell speed far exceeds the ballistic limit, but the fragments speed is much lower and the trajectory is formed by alternating waves of compression and decompression.

The punched-out tissue complex (skin-bone "imprimatum") in shots from captive-bolt guns: does it act as a secondary projectile?

From the first half of the twentieth century to the present day, injuries and fatalities from captive-bolt livestock stunners are a major topic in forensic medicine. The vast majority of cases account for suicides with the frontal, temporal, parietal, and occipital regions being the most common sites of entrance (in descending order of frequency). Due to the limited length of the bolt, the corresponding wound channel within the braincase is only several centimeters long. It has been a controversial subject for a long time, whether the skin-bone complex punched out by the conically grooved end of the steel rod may act as a "secondary projectile" being propelled beyond the actual path of the bolt. To answer this question, experimental shots from various types of captive bolt-guns were fired to simulants. Video-documentation employing a high-speed motion camera showed that the punched-out pieces of skin and bone did not move further than the bolt. Thus, a secondary extension of the total wound channel could not be observed. However, the suction effect caused by the bolt's rearward movement may induce a slight retrograde displacement of the skin-bone complex.

Radically Invasive Projectiles-first reports and imaging features of this new and dangerous bullet.

Recently, civilian patients have begun to present to emergency departments with a new type of bullet injury caused by a frangible bullet designed to splinter and deform in a predictable manner. This bullet "the Radically Invasive Projectile" (RIP) was developed by G2 Research (Winder, GA). In this article, we discuss the fragmentation pattern of this bullet as well present several illustrative cases in an effort to familiarize radiologists, surgeons and emergency medicine physicians with the characteristic wounding patterns and imaging appearances of this new variety of frangible ammunition.

Synergy of CT and MRI in detecting trajectories of lodged bullets in decedents and potential hazards concerning the heating and movement of bullets during MRI.

The purpose of this study was to assess the value of magnetic resonance imaging (MRI) in addition to computed tomography (CT) in gunshot wound cases with bullets or pellets lodged inside the head. In this context, the potential heating and movement of the lodged bullets were additionally investigated using animal models. Eleven forensic cases of penetrating gunshot wounds underwent CT and MRI. The data of each imaging modality were reviewed according to the following relevant characteristics: bony lesion at the entrance, intracranial bone fragments, intracranial metal fragments, gunshot residues, the wound channel and the severity of metal artifacts. Four-point Likert scales were used for the assessment. The heating of projectiles and their magnetic field interactions with the static magnetic field were assessed using animal models. MRI presented major advantages in cases with transversal trajectories and non-ferromagnetic bullets compared to CT. In general, MRI enabled a clear visualization of the wound channel and gunshot-related soft tissue injuries. An image fusion of CT and MRI datasets demonstrated the individual strengths of both modalities. Radio frequency (RF)-induced heating due to bullets lodged inside the brain tissue was invalidated. The likelihood of ferromagnetic projectile migration inside brain tissue is low. MRI of decedents with a bullet lodged inside their heads is viable and provides a valuable supplement to CT. The in situ, noninvasive depiction of the wound channel and gunshot-related soft tissue injuries on MRI can contribute to the knowledge of wound ballistics.

A novel hypothesis for the formation of conoidal projectile wounds in sandwich bones.

When perforated by a projectile, sandwich bones typically exhibit wounds with a distinct conoidal morphology that is widely utilised both in wound diagnosis and trajectory determinations. However, the dynamic fracture mechanisms underlying this intriguing wound type have yet to be experimentally verified. The most frequently quoted hypothesis for their formation, plug and spall, is difficult to reconcile with the conoidal morphology exhibited by such wounds. The present article carries out a high-speed videographic and micro-computerised tomographic (µ-CT) analysis of perpendicularly produced projectile wounds induced from 139.15 to 896.84 metres per second (m/s) in pig scapulae. Fundamental data on energy absorption, wound shape and bevel symmetry are presented. Cross-sectional fracture morphology revealed by µ-CT raises the novel hypothesis that tensile stresses induced by the projectile in the outer cortex elicit cone crack formation and that this cone crack then propagates catastrophically through the entire sandwich structure. This process results in the momentary formation of a bioceramic conoid, a conoidal volume of bone consisting of all three sandwich bone layers separated from the parent bone by the internal bevel. Fragmentation of the separated volume leaves the conoidal wound behind as its counterpart. The significance of this hypothesis in terms of differential diagnosis and interpretation of bevel shape is discussed.

Crack propagation through sandwich bones due to low-velocity projectile impact.

Projectile impact in sandwich bones typically results in formation of conoidal wounds exhibiting a larger region of damage on the inner cortical plate termed the bevel. To date, a number of hypotheses have been put forward to explain the formation of this wound type. The plug and spall hypothesis suggests that the conoidal morphology is produced by a two-phase mechanism of shear plug formation followed by internal bevel production during projectile exit. In contrast, the cone crack hypothesis suggests that such wounds are produced by cone crack propagation through the three laminae of the sandwich bone, resulting in the formation of bioceramic conoids consisting of all three bone laminae. In order to test these hypotheses, 28 non-human sandwich bones were impacted with 6-mm carbon steel spheres at velocities ranging from 26 to 96 metres per second (m/s). Impacts were filmed utilizing high-speed videography and fracture morphology analysed using micro-computerized tomography (µ-CT). Sequential increase in velocity successfully captured the genesis of conoidal wounds. Low-velocity impact produced circular depressed fractures in the outer cortex exhibiting angulated cortical fracture edges. An increase in velocity resulted in translaminar fracture and production of one intact and three fragmentary bioceramic conoids. At the highest velocities, conoids were fragmented and lost in the ejecta plume, with attached fragments undergoing dynamic movement during and after perforation. Significantly, projectile exit was not required for bevel production. The implications of these findings in wound interpretation are discussed.

Going big versus going small: Lithic miniaturization in hominin lithic technology.

Lithic miniaturization was one of our Pleistocene ancestors' more pervasive stone tool production strategies and it marks a key difference between human and non-human tool use. Frequently equated with "microlith" production, lithic miniaturization is a more complex, variable, and evolutionarily consequential phenomenon involving small backed tools, bladelets, small retouched tools, flakes, and small cores. In this review, we evaluate lithic miniaturization's various technological and functional elements. We examine archeological assumptions about why prehistoric stoneworkers engaged in processes of lithic miniaturization by making small stone tools, small elongated tools, and small retouched and backed tools. We point to functional differences that motivate different aspects of lithic miniaturization and several instances where archeological systematics have possibly led archeologists to false negative findings about lithic miniaturization. Finally, we suggest productive avenues by which archeologists can move closer to understanding the complex evolutionary forces driving variability in lithic miniaturization.

Attitude Measurement for High-Spinning Projectile with a Hollow MEMS IMU Consisting of Multiple Accelerometers and Gyros.

A low cost, high precision hollow structure MEMS IMU has been developed to measure the roll angular rate of a high-spinning projectile. The hollow MEMS IMU is realized by designing the scheme of non-centroid configuration of multiple accelerometers. Two dual-axis accelerometers are respectively mounted on the pitch axis and the yaw axis away from the center of mass of the high-spinning projectile. Three single-axis gyros are mounted orthogonal to each other to measure the angular rates, respectively. The roll gyro is not only used to judge the spinning direction, but also to measure and compensate for the low rotation speed of the high-spinning projectile. In order to improve the measurement accuracy of the sensor, the sensor output error is modeled and calibrated by the least square method. By analyzing the influence of noise statistical characteristics on angular rate solution accuracy, an adaptive unscented Kalman filter (AUKF) algorithm is proposed, which has a higher estimation accuracy than UKF algorithm. The feasibility of the method is verified by numerical simulation. By using the MEMS IMU device to build a semi-physical simulation platform, the solution accuracy of the angular rate is analyzed by simulating different rotation speeds of the projectile. Finally, the flight test is carried out on the rocket projectile with the hollow MEMS IMU. The test results show that the hollow MEMS IMU is reasonable and feasible, and it can calculate the roll angular rate in real time. Therefore, the hollow MEMS IMU designed in this paper has certain engineering application value for high-spinning projectiles.

A Novel Method for Estimating Pitch and Yaw of Rotating Projectiles Based on Dynamic Constraints.

This paper addresses the difficult problem of measuring the attitude of a high-spinning projectile and presents a novel method for estimating the pitch and yaw angles of the projectile in flight. The method is based on analysis of the external moment of the rotating projectile during flight and theoretical derivations obtained from the dynamics' equations. First, the principle of zero-crossing method is introduced, which explains the process of geomagnetic azimuth and roll measurements by the non-orthogonal geomagnetic sensor combination. Then, the dynamics constraint equations between the Euler angles and flight-path angle, trajectory deflection angle of the projectile are derived using the dynamics equations of the projectile rotating around the centroid, and analysis of the flight characteristics of the projectile in stable flight. Next, the spatial orientation relationship between pitch, yaw angles and magnetic azimuth is established based on the physical principle of geomagnetic azimuth. Finally, the pitch and yaw angles are estimated using the unscented Kalman filter (UKF), with the dynamics constraint equations serving as the driving equations. In the UKF prediction stage, the Runge-Kutta method is used to discretize the state equation that improves the prediction accuracy. Simulation results show that the proposed method can be used to accurately calculate the pitch and yaw angles, and results of experimental data processing also verify the feasibility of the proposed method for real-world applications.