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Bats colliding with spinning wind turbine blades result in bat mortality. Carcass surveys at individual wind turbines vary from daily to once a week and from large cleared plots to only the road and pad area. A physics‐based model is proposed to guide carcass surveys, for designing curtailment studies to detect treatment fatalities and for improving fatality estimates by accounting for unsearched areas. The model considers the effects of carcass size, weight, and drag, and it accounts for the turbine rotor size and rotation rate to simulate the trajectory of a carcass after it is struck by a wind turbine blade. A carcass parameter is defined as the ratio of drag force to body weight, which accounts for the relative effect of bat biophysical and aerodynamic characteristics. By applying restrictions on carcass survey and turbine yaw data, a limited sample of bat fatalities was obtained, and the analysis revealed that bats fall downwind of wind turbines, indicating wind drift significantly influences carcass fall trajectories. The new ballistics model includes the effect of wind drift on fall trajectory of a carcass. The model was used to investigate the sensitivity of carcass fall trajectories to variability of the input parameters. The tests showed that larger values of the carcass parameter, that is, when drag dominates, such as for small carcasses, resulted in larger downwind drift, whereas large carcasses with smaller carcass parameter values resulted in larger distances within the rotor plane. The relationship of wind speed and RPM was found to influence the carcass downwind distance more compared to the within rotor plane distance. Using carcass survey data, turbine operation data, and wind speed records, for seven bats surveyed the day after colliding with a wind turbine, modelled back‐trajectories were used to identify the likely strike location on the rotor. The model can be improved by validating the modelled trajectories with the recorded bat‐blade strikes in thermal videos. It should be noted that the findings of the present study are based on the bat fatalities that met strict criteria leading to small sample size and hence requires further evaluation for testing the robustness of the model.

Firearm injuries are a preventable epidemic in the USA. Extremities are commonly affected in gunshot injuries. Such injuries may be complex with concomitant osseous, soft tissue, and neurovascular components. The maximum wounding potential of a projectile is determined by its kinetic energy and the proportion of the kinetic energy that is transmitted to the target. Accurate assessment of ballistic injuries is dependent on utilizing the principles of wound ballistics, accurate bullet count, and ballistic trajectory analysis. The goals of this article are to review wound ballistics and the imaging evaluation of extremity civilian firearm injuries in the adult population, with emphasis on ballistic trajectory analysis, specific ballistic fracture patterns, and diffuse, secondary soft tissue ballistic injuries.

This paper presents the results of the theoretical external ballistic calculations for projectiles fired from barrels which correspond to the barrels used in two Polish small arms systems: MSBS- 5.56 system (MSBS GROT standard rifle and MSBS GROT carbine) and BERYL system (BERYL standard rifle and MINI BERYL carbine). The results obtained allowed the analyse of the effects of barrel length and the associated initial projectile velocity on the nature of projectile trajectory, particularly the over height and projectile range obtained along the trajectories. The analysis of the results facilitated an assessment of the scope of proposed changes in the settings of the firearm sights, resulting from the use of barrels of different lengths and the consequential changes in projectile trajectory.

Because of its excellent insulation capability, the usage of a silica-phenolic charring ablator as a nozzle liner is a common practice in the solid rocket motor industry. During the design of a solid rocket motor employing a silica-phenolic nozzle liner, it is desired to conduct an accurate analysis yielding in-depth thermal response and recession characteristics. As the interior ballistics and nozzle recession rate mutually interact, the best practice is to perform a coupled solution to both. Commonly used one-dimensional analysis tools with empirical approaches for estimation of convective heat transfer rate and blowing effect generally lack sought accuracy and do not model the transient shape-change phenomenon, which affects the nozzle performance. This Paper considers governing equations for charring, including pyrolysis gas injection and surface energy balance for melting ablation, along with a boundary condition governed by interior ballistics, and demonstrates a framework in which these equations are solved with governing equations for the nozzle flowfield in a coupled manner. Development and validation of a one-dimensional material response solver based on the same governing equations is also demonstrated. Also, results from a static firing test conducted with a small-scale ballistic evaluation motor employing a silica-phenolic nozzle insert are provided. Results from both investigations are compared and discussed.

Application of the method of removal of space debris objects by an ion beam - the IBS method - seems to be the most effective for cleaning the GEO region. This is due to the low energy consumption for transfer one object in a safe orbit delta-V≃11 m/s and the possibility of removal several objects by one spacecraft. The service spacecraft for this purpose can be developed on the basis of telsat technology, taking into account its functions. Such a spacecraft should contain an ion beam injector to act on the removed object and an electric propulsion system, which serves to compensate for the ion injector thrust and to control the spacecraft motion both during transportation of the removed object and during interorbital flights. The development of a weakly diverging ion beam injector, determination of the composition and structure of an electric propulsion system, ballistics of the optimal sequence of interorbital flights, and development of an algorithm for controlling a virtual cluster: spacecraft-removed object are discussed in the article. In the majority of works on IBS, commercial ion thrusters are considered as an ion injector and engines. However, ion beams from ion thrusters have a half angle of divergence of 120-150. When propagating in outer space, the ion beam expands irresistibly due to electron thermal effects. As a result, the distance at which the spacecraft must follow the removed object during its transportation for effective impulse transmission to it should be small (estimated, about 7 m). Taking into account the dimensions of both objects and the uncontrolled movement of the removed object relative to its center of mass, the object transportation operation carries noticeable risks. The results of an experimental study of a prototype of an ion injector with an initial half angle of divergence of 20-40 are presented. The use of such an injector would provide a distance between objects of 15–20 m and reduce the risk of their collision. In connection with IBS, various aspects of spacecraft control during transportation of an object with one, two or more engines as part of the electric propulsion system are considered. In the conceptual design of the spacecraft presented in this work, the electric propulsion system contains two stationary plasma thrusters, each of which is mounted with the possibility of independent rotation respect to two mutually perpendicular directions. Spacecraft motion control, including thrust vector control, is carried out by means of the thrusters coordinated rotation. The characteristics of the spacecraft and its subsystems intended for the removal of several objects are conceptually considered. For example, parameters of the mission for the removal of up to 10 objects from the NORAD catalog from the GEO region are given. In the future, using the result obtained, the control of SC of this scheme when IBS implementing in the low-Earth orbit will be considered.

A chronological synopsis of the history of the technology used in experimental and testing work relating to artillery pieces is presented. The period covered is from the mid-seventeenth century up ...

Purpose. The article analyzes assessment methods of existing fire extinguishing agent (FEA) jet ballistics. FEA discharge velocity from the nozzle effect on FEA drops in the air motion and trajectory has been investigated. Applying a new method for calculating FEA jets ballistics has been grounded. With the help of mathematical modeling, calculations have been carried out for FEA flow rate indicators depending on the pressure and flow rate for a universal nozzle, which forms different jet discharge angles from solid to spray. A model has been developed that describes FEA jet ballistics for both universal and conical or conoid fire nozzles. Methods. A logical method based on forces influence on a water drop in a medium has been used, as well as an empirical method, i.e. experiment. Findings. To confirm the developed jet ballistics theory, a series of field tests has been carried out. A fire monitor with a universal nozzle has been used as a test unit under the following conditions: equivalent diameter 29 mm; pressure in front of the nozzle 0.6 MPa; flow rate at the outlet 35 m/s (calculated by numerical simulation); nozzle inclination angle in relation to horizon 30°; nozzle cutting height from the horizon 1 m. The discrepancy in the indices of calculated and experimental jet range did not exceed 3 %. An insignificant effect of medium density change on jet range capability has been revealed, that is, under the same initial conditions, but at different ambient temperatures, fire extinguishing agent jet range capability will differ. This should be taken into account when using fire extinguishing installations based on monitors in different climatic regions. Research application field. The research results will simplify nozzle fire equipment development and design process, algorithm construction for robotic fire extinguishing installations operation based on fire monitors. Conclusions. The developed method for calculating jet ballistics is fully correlated with in-situ indicators. Jet ballistics is highly effected by fire extinguishing agents nozzle discharge velocity and medium density in which the fire extinguishing agent is flowing. In the future, it is required to conduct a number of scientific studies to determine extinguishing agent discharge velocity from various nozzles dependences on pressure and consumption.

The software for support of external ballistics calculation for weapons of 7.62 mm caliber is described taking into account external factors for the optical-electronic tactical exercise machine for small arms "Inhibitor" developed at the Institute of Mechanics UdmFRC UB RAS and at Computer facilities department of Kalashnikov ISTU jointly with JSC «Kalashnikov» Concern». A tactical and technical task is given for ballistic calculation of the trajectory up to 2 km of range of weapon simulators with a laser emitter of the targeting point taking into account external factors: types of sights, especially optical, ballistic scattering of bullets, deflection of the bullet from the side wind and derivation, which have a significant impact on the ballistic trajectory. The implemented differential mathematical model of external ballistics relying on the aiming angle of the weapon simulator depending on the sight readings, the initial speed and ballistic coefficient of various types of ammunition in real time builds a ballistic trajectory with adjustments for the air temperature and pressure and dependence on lateral wind and random dispersion of bullets to further solve the "problem of meeting" with obstacles. The given results of software tests for the error in calculating the coordinates of the ballistic trajectory showed full compliance with the requirements and adequacy of mathematical models. It was concluded that further research and development of electronic shooting simulators were promising thanks to the improvement of computing tools and the development of software libraries in order to increase the accuracy of simulating external ballistics of simulators taking into account many external factors, expand functional networks and reduce cost and, therefore, increase competitiveness.

In this research, there was considered a challenge of constructing a system of scientific knowledge of the shot conditions in judicial ballistics. It was observed that there are underlying factors that are intended to ensureits [scientific knowledge] consistency: identification of the list of shot conditions, which require consideration when solving expert-level research tasks on weapons, cartridges and traces of their action; determination of the communication systems in the course of objects’ interaction, which present the result of exposure to the conditions of the shot; classification of the shot conditions based on the grounds significant for solving scientific and practical problems. The article contains the characteristics of a constructive, functional factor (condition) of weapons and cartridges influence, environmental and fire factors, the structure of the target and its physical properties, situational and spatial factors, and projectile energy characteristics. Highlighted are the forms of connections formed in the course of objects’ interaction, proposed are the author’s classifications of forensically significant shooting conditions with them being divided on the basis of the following criteria: production from the object of interaction, production from a natural phenomenon, production method, results weapon operation and utilization, duration of exposure, type of structural connections between interaction objects, number of conditions that apply when firing and the forming traces.

The article is devoted to the study of the optimal control of propellant consumption during vertical lifting of rocket in homogeneous atmosphere using regularized solution of integral equation of the first kind. The problem of lifting of a rocket into desired height along optimal trajectory in the view of minimal consumption of propellant leads to solving the set of differential and integral equations. Problem of optimal control of propellant consumption during lifting of rocket in homogeneous atmosphere is solved using regularized solution of integral equation of the first kind which is solution of corresponding Euler equation on discrete time net. Influence of the regularization parameter and some additional parameters on precision of discreted problem is investigated. Considered algorithm is summed up easily to the case of non-homogeneous atmosphere by introducing dependence of the ballistic coefficient on altitude of flight and to problem of putting spacecraft into determined orbit and suborbital flights by setting desired altitude and velocity and modifying of motion equations.

A tandem bullet phenomenon is a rare situation in which two bullets travel nose-to-base towards the target. In terminal ballistics, a classic feature of the tandem bullet phenomenon is the presence of a single entrance wound with two or more bullets inside the body. During the autopsy, the phenomenon may result in confusion, especially related to the dynamics of the shooting. The present study reports a case of suicide by tandem bullets to the heart with subsequent bullet embolization into the aorta. A 40-year-old Caucasian woman, with a previous history of suicide, shot herself in the chest with a 0.32 revolver. During the autopsy, a single entrance wound (one centimeter in diameter) was observed in the sternal region. The injury was a close-range shot. Internally, a single wound was detected in the right atrium of the heart. Two 0.32 S&WL lead bullets were found inside the descending abdominal aorta. The bullets fitted each other perfectly in a nose-to-base position. Both bullets were tracked back to a single firearm that belonged to the victim’s father using forensic ballistics. The forensic report suggested a suicide. A multidisciplinary approach involving crime scene investigation, forensic pathology and forensic ballistics is necessary to investigate tandem bullet cases. Forensic experts must be aware of this phenomenon and, more importantly, they must be aware of its unusual manifestations, such as embolization, in order to come to optimal conclusions.

The article deals with the possible design of a new cartridge for an automatic assault rifle. This hypothetical design is based on the analysis of five automatic assault rifle cartridges which are currently used in armies: 7.62×51 mm NATO, 7.62×39 mm M. 43, 5.56×45 mm NATO and also another two cartridges which are under testing both 6.8×43 mm Rem. SPC and 6.5×38 mm Grendel. The analysis of a new cartridge including internal ballistics, external ballistics, and terminal ballistics energy disposed to the target upon an impact is introduced in the article. The goal was to create a cartridge that would have better ballistic performance than 5.56×45 mm NATO and it would still possess enough accuracy of fire and speed, so that it could dispose at least minimal kinetic energy necessary to incapacitate individuals. Also it is important to maintain the constancy of this effect for the long distance shooting, somewhere around 500 m, during battles in an open area (effective range of 5.56×45 mm automatic assault rifles is normally of about 300 m what only suffices in close quarter battles). To achieve it, the bullet must have the higher sectional density than the 5.56×45 mm cartridge. The sectional density reflects the capability of bullet to penetrate through the human tissue within the requirements of wound ballistics. Based on the analysis, the value of sectional density should be approximately of 0.21 g/mm2. The function of fully automatic firing depends on the size of the recoil energy of a weapon which is also related to the muzzle energy that cannot surpass the amount of 2 500 J. The new cartridge design is based on the 6 mm Scenar bullet (FMJ - Full Metal Jacket bullet with a weight of 5.8 g) made by the Lapua Company. All the ballistic parameters must be within the intervals of strength and construction possibilities of small arms ammunition. To create a possible variation of the mentioned cartridge where its bullet will be powered by a nitrocellulose propellant (originally made in Czech Republic) and a new cartridge case will be created.

Few firearms have attracted as much attention, curiosity, and mythical attributes as the blunderbuss. Indeed, it often seems that fiction has overwhelmed the facts. To add to the mystery, the liter...

Modern system accuracy studies require high fidelity representations of environmental phenomena in order to accurately predict the down range performance of a gun system. One component of the atmosphere that has not been studied in great detail within the ballistic domain is turbulence. The current portrayal of wind leveraged by system analysis efforts ignores this element of atmospheric motion completely and thus its effects on down range dispersion have not been quantified. As a first step in addressing this deficiency, this study develops a methodology for generating synthetic turbulent wind signals along the flight path of a projectile. This goal is accomplished by integrating the work of several authors, developing techniques to fill knowledge gaps, and tailoring the solution to the direct fire domain. The significant contributions of the presented effort include mean flow direction agnostic spectral functions, provisions to account for the non-homogeneity of turbulence parameters along a trajectory, and a higher fidelity signal generation method than was used in previous work. The new information is applied to a sample engagement scenario in order to demonstrate the realization of the given techniques within the small caliber direct fire domain.

The problem of launching a rocket into the Earth's orbit has already been solved using the regularization method in previous studies. But the regularization method remains relevant for application to solving integral equations of the first kind, which determine the components of speed and acceleration. The problem of optimal control of propellant consumption during the insertion of a rocket into a circle orbit of the Earth is solved using regularized solutions of integral equations of the first kind which are solutions of corresponding Euler equations on discrete-time net. The influence of the regularization parameter and some additional parameters on precision of discredited problem is investigated. Calculations are carried out for existing chemical rocket engine and promising plasmic one. Considered algorithm is summed up easily to problem of suborbital flights by setting desired coordinate system and modifying motion equations. Conclusions were drawn about the required speed for the lowest fuel consumption, as well as about the problem for a single-stage rocket. Thus, the development of a plasma rocket engine with an exhaust velocity is more than ten times higher than that of a chemical one.

Quality practices in forensic science are often in tension with providing timely results. When the Costa Rican Department of Forensic Sciences ballistics unit achieved accreditation under ISO/IEC 17020:2012 in 2018, the unit started experiencing slower turnaround times. With a view to expediting the resolution of forensic examination processes, the unit undertook a Lean Six Sigma project with a five-phase problem-solving methodology. The unit began to use data and process tools to transform its current state. The completion of all phases showed that two main aspects were preventing the laboratory from fulfilling the customers’ expectations: standardization and constraints. This project took 6 months and improvements were seen through the reduction of the number of pending cases with a backlog of more than 3 months by 97% and the turnaround time from 4 months to 1 month. Through this project, leadership identified an effective methodology, creating a positive impact on customers’ expectations.

At this time, a scientific approach has developed in ballistics, in which the topic of the conditions of the shot is addressed only within solving its individual issues. This causes fragmentation and incompleteness of information about the conditions of a shot in judicial ballistics, hinders its development, reduces the possibility of a forensic ballistic examination in providing disclosure and investigation of crimes. In order to solve the problem, the authors examined the nature of scientific knowledge about the conditions of a shot in judicial ballistics, assessed their place in the system of judicial ballistics, identified areas of scientific knowledge that determine their content. It is established that scientific knowledge about the conditions of the shot is derived from judicial ballistics and is of a theoretical and applied nature, reflecting the principle of building knowledge, their focus on taking into account the influence of these conditions in displaying the properties and attributes of weapons, cartridges and traces of their action in solving expert problems. The process of generating information about the conditions of the shot, in addition to the scientific and methodological apparatus of forensic ballistics, determines the integration of the scientific knowledge of forensics, forensics, military equipment and forensic medicine. An element of the development of judicial ballistics is the structural isolation in it of a section containing a system of scientific knowledge about the conditions of the shot. This will allow focusing on the theoretical, methodological and organizational side of the problem, create conditions for increasing the scientific and methodological support of forensic ballistic expert studies.

Firing accuracy is a critical quantity of interest in the performance analysis of electromagnetic railgun (EMRG) exterior ballistics. Since the simulation technique is always used to simulate the complex physical system at a low cost, it is employed to evaluate the firing accuracy of railgun projectile with uncertainty in this paper. An exterior ballistics simulation model of the railgun, including 3-DOF flight mechanical model, relative kinematic model, and guidance law model, is developed to simulate the ballistics behavior in the missile target intercept mission. The firing accuracy is studied in this paper to compare the capability of EMRG with different ranges and muzzle velocities. In order to explore the firing accuracy of the guided projectile, the guidance precision analysis and ballistics uncertainty quantification are studied. In the guidance precision analysis, the shot range and efficiency are used to make a comparison. In addition, the sensitivity analysis and firing accuracy analysis are also performed in terms of uncertainty quantification. The simulation results illustrate that the simulation of the guided projectile can give some practical guide to the projectile design of EMRG.

The identification of firearms from forensic ballistics specimens is an exacting and intensive activity performed by specialists with extensive experience. The introduction of imaging technology to assist the identification process of firearms has enhanced the ability of forensic ballisticians to conduct analyses of these specimens for identification. The positive identification of ballistics specimens from imaging systems are important applications of technology in criminal investigation [1] [2] [3] [4]. While the image capture methodology for persons and forensic ballistics specimens is similar, the process of identification for each is dependent upon the level of certainty required for the identification. The forensic identification of ballistics specimens relies on the detection, recognition and ultimate matching of markings on the surfaces of cartridges and projectiles made by the firearms [5]. Traditional methods for the comparison of these marks are based on incident light microscopy. The image formed from the oblique illumination of the mark gives a representation of the surface of the specimen in the region of the mark [6]. This representation is critically dependent on the material of the surface on which the marks have been made, and the geometry and intensity of the illumination system. The assessment by the ballistician of the similarity between comparable marks on respective ballistics specimens from crime scenes and test firings will be based on the expertise and experience of the technologist. Thus the traditional method of matching markings has inherent difficulties, and entails an element of subjectivity [7]. The need for firearm identification systems by police services continues to increase with greater accessibility to weapons in the international contexts. The characteristic markings on the cartridge and projectile of a bullet fired from a gun can be recognized as a fingerprint for identification of the firearm [8]. Forensic ballistics imaging has the capacity to produce highresolution digital images of cartridge cases and projectiles for matching to a library of ballistics images [9]. However, the reliance upon imaging technologies makes identification of ballistics specimens both a demanding and exacting task, where the control of the error of

Hybrid rocket engines (HREs) are a chemical propulsion system that nominally combine the advantages of liquid-propellant rocket engines (LREs) and solid-propellant rocket motors (SRMs). HREs in some cases can have a higher specific impulse and better controllability than SRMs, and lower cost and engineering complexity than LREs. For HREs and SRMs, both kinds of rocket engine employ a solid fuel grain, and the chosen grain configuration is a crucial point of their design. Different grain configurations have different internal ballistic behavior, which in turn can deliver different engine performance. A cylindrical grain design is a very common design for SRMs and HREs. A non-cylindrical-grain is a more complex grain configuration (than cylindrical) that has been used in many SRMs, and is also a choice for some HREs. However, while an HRE and an SRM can employ the same fuel grain configuration, the resulting internal ballistic behavior would not be expected to be the same. Pressure-dependent burning tends to dominate in SRMs, while axial flow-dependent burning tends to dominate in HREs. To help demonstrate in a more direct manner the influence of the differing combustion processes on the same fuel grain configuration used by an HRE and SRM, a number of internal ballistic simulations are undertaken for the present study. For the reference SRM cases looked at, an internal ballistic simulation program that has the capability of predicting head-end pressure and thrust as a function of time into a simulated firing is utilized for the present investigation; for the corresponding HRE cases, a simulation program is used to simulate the burning and flow process of these engines. For the present investigation, the two simulation programs are used to simulate the internal ballistic performance of various HREs and SRMs employing comparable cylindrical and non-cylindrical fuel grain configurations. The predicted performance results, in terms of pressure and thrust, are consistent with expectations that one would have for both propulsion system types.

Booming technological advances and turbulent military reforms have promoted the continuous advancement of weapons and equipment. High-power microwave (HPM) weapons have changed the damage modes of traditional guns, missiles and other kinetic energy weapons, as well as having the huge advantage of "changing the rules of the game." The study of exterior ballistics of high-power microwave weapons has theoretical support for the design and development of weapons and the verification of performance indicators, and is also an important basis in the firing application of high-power microwave weapons. By studying the coupling mechanism between HPM weapons and targets, an exterior ballistics description of HPM weapons is given According to the description of exterior ballistics, the differences between HPM and traditional weapons in definitions, accuracies, space trajectories, space descriptions and "end points" are summarized and the exterior ballistics space transmission is established. This study reveals the nine major transmission laws of the exterior ballistics of HPM weapons. The constructed model and related theories of the transmission laws for exterior ballistics lay a theoretical foundation for the in-depth study of key technologies of HPM weapons, such as fire control and damage assessment.

Projectile injuries to the face deserve particular attention to evaluate for involvement of critical structures and functional elements and treat the devastating effects on facial aesthetics. Ballistic trauma to the maxillofacial region often has significant soft tissue and bony defects, creating a greater challenge to the reconstructive surgeon. The main goals of treatment of projectile injuries to the face are decreasing the amount of contaminants and nonviable tissue at the site, ensuring functionality, and restoring aesthetic appearance. There exists a lack of robust research on the subject. Soft tissue injuries from high-velocity projectiles have changed the perspective on treating acute injuries to the face and neck. Injuries encountered during both Operation Iraqi Freedom and Operation Enduring Freedom give the author pause to reflect upon a different wounding pattern than that encountered in stateside trauma centers. Given the dissemination of high-velocity weaponry by enemy combatants such as the improvised explosive device, mortar round, and high-velocity rifles, a higher incidence of facial wounds has been reported. The mechanism of injury and a stepwise approach for surgical repair are discussed incorporating advanced trauma life support principles and a reconstructive ladder of repair.

A 28-year-old male presented to the emergency department with an isolated ulnar shaft fracture secondary to a ballistic injury with a wooden pellet gun. This injury is also known as a “nightstick fracture,” which is a common eponym in orthopedic surgery used to describe a fracture of the ulnar shaft. The eponym gained its title for the injury commonly seen when in a defensive position while being attacked with a wooden club. It is widely accepted that this infamous injury was popularized in the 1960s as a sequela of the many race-related riots across the United States. This case details how the nightstick fracture is still prevalent as a result of political protesting today, despite modern-day methods of non-lethal riot control.

This work presents a novel approach for the modeling of the entrainment in the numerical simulation of the internal ballistics of hybrid rocket engines with paraffin-based fuels. This model, coupled with a more sophisticated gas–surface interaction treatment, is an improvement of the model previously developed by some of the authors, which was based on some oversimplifying assumptions. Indeed, the old entrainment model was performed in a close range of averaged oxidizer mass flux, and it made the overall numerical model not scalable on different motor sizes. Therefore, a new correlation is introduced, which is based on the Reynolds number and takes into account the dependence of the entrained fraction on the shear stress exerted by the gas flow and the tube diameter. Firstly, the new and the old numerical models are compared in order to highlight the improvement obtained by the current efforts. Then, the model has been validated on experimental tests involving two different thrust class motors. Finally, the effect of the motor size on the fuel consumption is shown, thus revealing the crucial influence of the recirculating zone extension due to the oxidizer axial injection.

At the initial stage of the creation of new types of launch vehicles, the so-called design ballistic calculations are carried out. The main purpose of these calculations - is to make the choice of optimal combinations of the main design parameters. Currently, the relevance of the project ballistics tasks has grown significantly in the connection with the research of the new generation of launch vehicles, which are related to both the problems of deep space exploration and the creation of low-orbit satellite constellations of small spacecraft. In the process of the design methods developing, models of motion should not be inferior to the uncertainties of the source data. So, the algorithms of these methods should reflect the correlation of design parameters with the flight characteristics of the launch vehicle. Above principles were put as the basis of the proposed correlations linking the values of the trajectory variables at the end of the launching phase of the first stages of launch vehicles with the main design parameters. The calculated dependences are based on the results of the analysis of a large number of trajectories, which are corresponding to variations of different studied factors. The calculations were carried out by the method of numerical integration of differential equations of motion in a wide range of variation of the source data. The analysis done gave us the possibility to identify some general patterns of controlled motion of a material point and to obtain the structure of calculation formulas in an analytical form.

People have felt the need for protection both in daily life and during the war throughout history, and as a result of these needs, they have been constantly searching for new materials to find better protection. People have used different kinds of materials for protection from animal skin, wood, metals, and now composites. Different kinds of protective armors had made up till now for protection from different threats. With the emergence of ballistic science, the work in this area has gained momentum, and it has become more important to check whether the designed products meet the desired needs. There are several international standards used to test the effectiveness of ballistic protection from different threats. Within the scope of these standards, performance of ballistic protective armors is investigated, and their effectiveness is determined. This chapter includes recent and current research trends for protection against ever-expanding ballistics. It also includes solutions for next-generation threats like new materials that were invented recently and will be used in future ballistic armors. It also includes as a part the green solutions for ballistics that used renewable resources and provides eco-friendly protective solutions.

In order to achieve multi-objective optimization design of ballistics and improve the power of weapons, an optimization model for the internal ballistic simulation design of the propellant charge was established. Based on the requirements of artillery ballistic performance, the model took several influences into account, such as type, charge mass (ω) and web thickness (2e1). The objective function was composed of muzzle velocity (v0), maximum chamber pressure (pm), relative burnout point (ηk) equations. The computational program used recursive algorithm to calculate and select reasonable charge results by looping the internal ballistics and optimization design equation sets. 105 mm artillery and 122 mm artillery were selected as examples to optimize the charge design. The results show that compared with the existing charging scheme, the loading scheme optimized by the model can reduce the relative burnout point of 105 mm artillery by 0.21 in the case of the muzzle velocity, and the maximum chamber pressure have a little difference. The maximum chamber pressure of the 122 mm artillery reduces by 2.83% while the muzzle velocity increases by 1.13%.

Background Treatment of gunshot wounds of the brain (GSWB) remains controversial and there is high variation in reported survival rates (from 90%) depending on the etiology and country. We retrospectively analyzed the outcome of a series of consecutive GSWB patients admitted alive to a level 1 trauma center in a safe high-income welfare country with a low rate of homicidal gun violence. Methods Patients admitted due to a GSWB to the HUS Helsinki University Hospital during 2000–2012 were identified from hospital discharge registry and log books of the emergency room and ICU. CT scans and medical records of these patients were reviewed. Univariate analysis and backward logistic regression were performed, and their results compared with that of a systematic literature review of factors related to the outcome of GSWB patients. Results Sixty-four patients admitted alive after GSWB were identified. Eighty percent had self-inflicted GSWB, 81% were contact shots, and 70% were caused by handguns. In-hospital mortality was 72%. Factors associated with mortality in our series were low GCS (≤ 8) at admission, transventricular bullet trajectory, and associated damage to deep brain structures, as reported before in the literature. Of the 64 patients admitted alive, 42% (27/64) were admitted to ICU, 34% (22/64) underwent surgery, and in 25% (16/64), craniotomy and hematoma evacuation was performed. Mortality in the surgically treated group was 32% but near 100% without surgery and ICU treatment. Median GOS in the surgically treated patients was 3 (range 1–5). Conclusions GSWB caused by contact shot from handguns has a high mortality rate, but can be survived with reasonable outcome if limited to lobar injury without significant damage to deep brain structures or brain stem. In such GSWB patients, initial aggressive resuscitation, ICU admission, and surgery seem indicated. Electronic supplementary material The online version of this article (10.1007/s00701-019-03952-y) contains supplementary material, which is available to authorized users.

In this paper, the effect of the chemical composition of .22LR bullets was studied and correlated to the extent and quality of the markings left after shooting them with the same gun. Scanning electron microscopy and optical comparator microscopy equipped with 3D and profilometry modules were used as non destructive techniques with two main purposes. The first is to assist the firearm examiner in the choice of the ammunition most suitable for preparing the test bullets. The second is to propose an approach, crossing data from optical microscopy, profilometry and space-resolved chemical analysis, for explaining the morphology of striae, whether continuous or interrupted. Among the most notable results is the finding that commercial .22LR ammunition show very wide interbrand, interlot and intralot variability. A selection of test ammunition solely based on the same brand and model used on the crime scene is therefore not suitable, urging the need for a more accurate choice, based on a preliminary chemical analysis.

The meteorological data profiles are used in various strategic applications including Military Ballistics, Weather Forecasting, Boundary Layer Research and Climate Studies. The recorded data are ac...

Firearm-related exhibits are often found at crime scenes. These exhibits may include the firearm, cartridges, cartridges cases or bullets. As ammunition needs to be handled to load the weapon, rega...

Ballistic traumas are defined by a projectile entering the body. Such projectiles include bullets, birdshot, and metal fragments from the covering or the contents of an explosive device. They frequently cause severe wounds characterized by a range of clinical pictures and a large spectrum of concomitant wounds. The major aims of imaging are to define the path of the projectile or projectiles, to evaluate which tissues have been injured, to estimate the severity of injury, and to determine what additional studies are needed. A routine radiograph is performed in patients with gunshot wounds. The diagnostic approach has been changed by the use of multidetector row computed tomography (MDCT) due to its technical developments particularly faster data acquisition and advanced image reconstructions. In the evaluation of patients with gunshot injuries, MDCT is considered the method of choice to identify hemorrhage, bullet, bone fragments, air, hemothorax, nerve lesions, musculoskeletal lesions, and vessel injuries. Moreover, MDCT technology and multiplanar reformation postprocessing allow meticulous trajectory analysis that potentially benefits the clinical outcomes of patients aiding time-saving triage and correct image-based diagnosis of organ and vessel damage. Familiarity of ballistics and forensic sciences will therefore help the radiologist in assessment and localization of the damage caused by projectiles.

Highlights • Ballistic tramatology in the upper humerus extremity region presents challenging management difficulties. • Resurfacing shoulder hemi arthroplasty in ballistic injuries is not commonly reported. • The indication of resurfacing shoulder hemi arthroplasty was appropriate regarding good functional outcome., Introduction Ballistic traumatology of the shoulder joint is uncommon. Usually, it is associated to comminuted fractures of the upper humerus. Total shoulder arthroplasty has been proposed to restore a good function. The indication of resurfacing hemi arthroplasty still controversial and is not commonly reported after ballistic traumatology. Presentation of case We report the case of a 26-year-old soldier victim of a gunshot of the left shoulder entailing a comminuted complex fracture of the upper extremity of the humerus. After shoulder immobilization of 3 months joint mobility was very limited. Radiographs showed bone malunion with a total loss of the hemispherical form of the humeral head. Patient has undergone a resurfacing hemi arthroplasty. Surgery outcome was good. At five years of follow-up, there were no major functional complaints. Clinical and radiological result was satisfactory with a good shoulder mobility. Discussion Shoulder arthroplasty provided good functional outcome in case of post fracture sequelae. Difficulty was to choose between total arthroplasty and hemi arthroplasty. In young and active patients, authors disapproved total arthroplasty in post traumatic gleno-humeral arthrosis to prevent revision difficulties especially after glenoid erosion. Conclusion Although follow-up still be limited, the indication of shoulder hemi arthroplasty was appropriate regarding functional outcome and patient satisfaction. Further clinical and radiological supervision still necessary to detect glenoid erosion.

The article is focused on the development of the underwater ballistic model of a supercavitating projectile fired from an underwater firearm. The supercavitating flows and their influences on the ballistic characteristics of the projectile are studied. The presented mathematical model is validated and experimentally verified for the supercavitating projectile of 5.7 mm in diameter fired from a smooth bore underwater rifle.

Sabot asymmetric discard after the projectile being launched from the muzzle at various angles of attack and 4Ma is investigated. This is implemented by the coupling computational fluid dynamics (CFD) and six degrees-of-freedom exterior ballistic code through the unstructured dynamic mesh and user defined function. The flow field characteristics during sabot discard process and the trajectory parameters of all three sabots have been obtained. In addition, the aerodynamic coefficients of the projectile are also obtained. The numerical results show that the asymmetric discard of sabot is more obvious along with the increasing angle of attack. Moreover, the aerodynamic forces of projectile have a larger change and the pressure distribution of its surface is more asymmetric and complex. This means the aerodynamic interference at a non-zero angle of attack contributes more significantly to shooting dispersion and flight stability than that at zero angle of attack and the influence increases as the angle of attack increases.

This article is concerned with the issue related to studying the dynamic properties of the aerial target imitator. Applying the modelling principles, the structure and technical data of aerial target imitator were described and utilising the PRODAS software a physical model of the aerial imitator was developed based on the conducted simulation studies. Mass, aerodynamic and basic parameters of flight path were determined. Then, experimental studies of basic dynamic characteristics were discussed. The comparison of results obtained from experimental and theoretical studies proves the correctness of the developed model.

Tha paper focuses on the problems of unmanned cruciform winged glider dynamics and control in autonomous flight conditions, and studies the wing aspect ratio effect on its flight performance. The winged glider control structure in the longitudinal and lateral axes is proposed. We carried out a comparative analysis of the ballistic flight ranges of models of different configurations, as well as the flight ranges of models of different configurations in the operating conditions of the control system of the proposed structure. As a result, the structure of the unmanned winged glider targeting system is proposed. The targeting system in the longitudinal axis, unlike the samples used in currently operating models, consists of two subsystems responsible for the unmanned winged glider best range gliding at the first flight phase and the direct aimpoint guidance at the second, i.e. final, flight stage

The penetration of projectiles into semi-infinite targets helps in the understanding and modelling of terminal ballistics. The article describes field test results of 5.56×45 mm F1 Ball and 7.62×51 mm M80 Ball ammunition. The targets were 25-mm-thick mild and high strength steel plates of Grade 250 MPa and 350 MPa, respectively. The tests recorded penetration depth, muzzle and impact velocities, and bullet mass. Despite its smaller calibre, the 5.56 mm × 45 mm F1 Ball ammunition recorded deeper penetrations than the larger calibre 7.62 mm × 51 mm M80 Ball ammunition. This is due to the 5.56 mm ammunition comprising a hardened steel penetrator and lead core, whereas the 7.62 mm ammunition comprised only a lead core. Multiple shots were fired for each type of munition. The coefficient of variation of steel penetration is approximately 0.10 and 0.03 for 5.56 mm and 7.62 mm rounds, respectively. The article also presents predictive models of steel penetration depth and compares these to the field test results.

A mathematical model is developed to characterize the progressive time-evolution of a fragmenting incandescent object. The objective of these models is to provide a spatio-thermal footprint of the fragmentation field, which can be useful to guide fire safety rules in manufacturing workplaces, as well as to estimate fire hazards. Ascertaining the time-evolution of the temperature of the fragments is quite difficult to measure experimentally, which motivates the model development. Initially, analytical models based solely on ballistics, which provide qualitative trends, are developed to provide insight into the fundamental ratios that govern safe operating conditions. Thereafter, rapid numerical spatio-thermal models, which provide quantitative information, are then developed, based on particle methods. The model uses the released energy from the initial blast pulse to provide the starting kinetic energy of the system of particles and then numerically computes the trajectory and thermal state of the fragments under the influence of Numerical examples and provided and extensions to high-fidelity are discussed.

INTRODUCTION: Training using ultrasound phantoms allows for safe introduction to clinical skills and is associated with improved in-hospital performance. Many materials have been utilized to simulate human tissue in phantoms including commercial manikins, agar, gelatin, and Ballistics Gel, however phantom tissues could be improved to provide higher fidelity ultrasound images or tactile sensation. This paper describes a novel phantom tissue mixture of a modified polyvinyl chloride (PVC) polymer, mineral oil, and chalk powder and evaluates needle cutting and ultrasonic properties of the modified PVC polymer mixture compared to a variety of phantom tissues. METHODS: The first experiment measured axial needle forces of a needle insertion into nine phantom materials, including three formulations of modified PVC. The second experiment used a pairwise comparison survey of ultrasound images to determine the perceived realism of phantom ultrasound images. RESULTS: It was found that the materials of Ballistics Gel and one of the PVC mixtures provide stiff force feedback similar to cadaver tissue. Other phantom materials including agar and gelatin, provide very weak unrealistic force feedback. The survey results showed the PVC mixtures being viewed as the most realistic by the survey participants, while agar and ballistics gel were seen as the least realistic. CONCLUSIONS: The realism in cutting force and ultrasound visualization was determined for a variety of phantom materials. Novel modified PVC polymer, has great potential for use in ultrasound phantoms because of its realistic ultrasound imaging and modifiable stiffness. This customizability allows for easy creation of multilayer tissue phantoms.

Body armor is tested for efficacy using the NIJ’s clay standard. This standard is based on a 44 mm upper limit of back face deformation into the clay to prevent severe cases of behind armor blunt trauma (BABT). The NIJ clay standard has never been directly correlated with human injury, and it is previously unknown how 44 mm into clay translates to the response of a human torso. This study developed a method for reproducing BABT in a laboratory setting, and performed matched pair testing on the ballistics clay and a cadaveric specimen. Tests at a low, non-injurious speed and a high, injurious speed were performed at the NIJ specified clay temperature, along with two tests at a lower temperature representing exposure to a room temperature setting. It was found that for both speeds the displacement into the human thorax was greater than the displacement into the clay. The greatest displacement into the clay was only 5mm above the standard’s limit, and the same speed into the human model caused failure of the ribcage. Lowering the clay temperature by two degrees Celsius resulted in a passing clay displacement for the extremely injurious high speed test. This experimentation is sufficient in showing that the NIJ standard may not be valid for preventing serious BABT injuries in the wearers of body armor. Further testing is required to correlate clay displacements with human injury risk.

Several three-dimensional scanning methods have been developed and improved over the past 40 years. The peculiarities of each technique, associated with the computational advances of the period, allowed the increasing application and diffusion of the technology in several sectors, among them those related to metrology in ballistics and the testing of protective materials. The specific goal of such ballistic tests is to estimate the depth of indentation caused by projectiles. In particular, this study presents a comparative analysis between two three-dimensional optical scanning methods, taking into account the same object of interest. The comparative analysis was based on reference planes detected by Random Sample Consensus methodology in each cloud. By comparing the results of the different techniques, it was found for this case that three-dimensional reconstruction by stereo images estimated values closer to the real ones in comparison to those estimated by the structured light scanner, mainly due to the fact that, for three-dimensional reconstruction, the image acquisition was conducted statically.

What is the role of real-time control and learning in the formation of social conventions? To answer this question, we propose a computational model that matches human behavioral data in a social decision-making game that was analyzed both in discrete-time and continuous-time setups. Furthermore, unlike previous approaches, our model takes into account the role of sensorimotor control loops in embodied decision-making scenarios. For this purpose, we introduce the Control-based Reinforcement Learning (CRL) model. CRL is grounded in the Distributed Adaptive Control (DAC) theory of mind and brain, where low-level sensorimotor control is modulated through perceptual and behavioral learning in a layered structure. CRL follows these principles by implementing a feedback control loop handling the agent's reactive behaviors (pre-wired reflexes), along with an adaptive layer that uses reinforcement learning to maximize long-term reward. We test our model in a multi-agent game-theoretic task in which coordination must be achieved to find an optimal solution. We show that CRL is able to reach human-level performance on standard game-theoretic metrics such as efficiency in acquiring rewards and fairness in reward distribution., Comment: 16 pages, 7 figures

Resumen de la tesis: Among all energetic materials, the combustion of granulated, composite AP/HTPB and double-base solid propellants are studied in thesis. The improvement on the design and safety in industrial processes which use solid propellants are of major importance in industry of energetic materials. Unexpected detonation of granular solid propellants is a key safety issue. Moreover, ignition and subsequent combustion of granular solid propellants are also complex mechanisms of high importance in the manufacturing process of many energetic materials, not only because already mentioned safety issues, but also in due in the design of propulsion systems. Therefore, and in order to properly understand this problem, a model for the characterisation of the detonation process of granular solid propellants under shock tube conditions is developed. To be able to reach this objective, a two-phase model, which considers the conservation equations of mass, momentum and energy and constitutive relations of mass generation, gas-solid particle interaction, interface heat transfer and particle-particle stress is defined. The study performed in this thesis, improve the understanding and modelling of the deflagration-to-denotation (DDT) phenomenon in granular beds of solid propellants. Two different models have been used to calculate pressure, temperature and porosity distributions. The first model considered a modification of the particle momentum governing equation in order to prevent the porosity from reaching values below the minimum value of compaction defined for packed beds of spherical particles. The second model studied does not consider the porosity limiter in the momentum conservation equation but represents the limitation of the porosity directly in the code by preventing the porosity to reach values below a minimum. In addition, the results are obtained by employing several numerical schemes and are compared against those available in the bibliographical sources in order to assess their effectivity to predict the early stages of this transient combustion process. The results show that developed second model accurately represents the physical behaviour of the propellant combustion for all variables of interest becoming a predictive tool for the characterisation of granulated solid propellants. Modelling the combustion of composite propellants and double-base propellants is a key problem that has focused the interest of several researches in many industrial fields such as chemical engineering, aerospace engineering or safety in industrial processes. Regarding safety, not only gun tubes, but also rocket motors experiment pressure build-up which could increase the chamber pressure, causing the explosion of the rocket motor being of high importance to develop models which could represent accurately the combustion process of these materials. Modelling the combustion of these propellants has been also of high interest for researchers in terms of optimising chemical composition to fulfil industrial requirements, improve propellant design, development and testing activities. The analysis of the burning rate of these materials, which means their decomposition and their subsequent combustion, is one of the main objectives of combustion modelling. Therefore, in this work, a transient multidimensional numerical model to describe the combustion of composite and double-base solid propellants is presented. The kinetics of the model is described by considering firstly, a change of phase of the solid propellant from condensed to gas and secondly, a reduced chemistry scheme which defines simplified chemical reactions to represent the combustion itself. To couple both processes, mass and species conservation, as well as temperature continuity are imposed in the burning surface in which the burning rate will represent a key factor. Moreover, an energy balance is also applied at the burning surface which represents that heat that the gas transfers to the burning surface is invested firstly, in raising the surface temperature to produce the phase change and secondly, in warming the condensed phase by conduction. The results obtained in the combustion modelling of both, composite and double-base solid propellants, are compared against experimental test and results present in the existing literature. An absolute error between 0.4 mm/s and 1 mm/s is obtained being in the order of magnitude of the experimental error. In addition, the pressure oscillations produced in a rocket motor and the depressurisation suffered in a combustion chamber, as well as at the exit of a barrel, are very interesting technological problems which have not been deeply studied in the literature. Therefore, the results obtained in the numerical modelling of transient combustion of composite and double-base solid propellants are presented in this thesis too. To perform this analysis, a pressure ramp is applied during a short interval of time at the open side of the already defined geometries. The developed tool confirms its robustness for the prediction of composite and double-base propellants combustion behaviour in multidimensional scenarios with transient environmental conditions such as rocket engines and/or base bleed units in ballistics applications.

A predictive numerical approach, based on Reynolds-averaged Navier–Stokes simulations including the effects of turbulence, chemistry, fluid/surface interaction, and radiation, has been developed fo...