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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. [ABSTRACT FROM AUTHOR]

Population reduction or eradication of domestic or non-domestic species may be required to address their impacts on the environment, other species, or human interests. Firearms are often used to accomplish these practical management objectives, and there is increased concern that the methods used may compromise animal welfare. We document the accuracy and humaneness of gunshot placement to the brain and cervical vertebrae of Philippine deer (Rusa marianna) on Guam during depopulation activities as a model for meeting AVMA standards of euthanasia under field conditions (e.g., animal is not in hand). Deer were shot with a .223 caliber rifle from 10–125 m and approached immediately (<20 s) for assessment. A subset of adult deer was further evaluated for physiological responses including cessation of heart rate, respiration, ocular reflexes, and post-mortem spasms. All deer shot in the brain (n = 132) and upper cervical spine (C1—C3; n = 18) died immediately due to the destruction of the brain or spinal tissue. Shot placements were all within 1.9 cm of the point of aim (i.e., the center of the target region). The accuracy and immediate insensibility resulting from targeting of C1—C3 demonstrates that this is an alternative target site when animal positioning is not optimal for targeting the brain, or there is a need to preserve brain tissue (e.g., Chronic Wasting Disease testing). While targeting of C4 –C7 vertebrae (n = 6) was accurate and resulted in immediate incapacitation, the failure to produce immediate insensibility does not support the use of this shot placement when upper cervical or brain shot placement is an option. It is reasonable to achieve sufficient accuracy to target the brain or upper cervical vertebrae of deer under field conditions and meet standards of euthanasia while accomplishing management objectives. [ABSTRACT FROM AUTHOR]

A large body of evidence demonstrates that resistance training has been ineffective for improving walking outcomes in adults with neurological conditions. However, evidence suggests that previous studies have not aligned resistance exercise prescription to muscle function when walking. The main aim of this study was to determine whether a training seminar for clinicians could improve knowledge of gait and align resistance exercise prescription to the biomechanics of gait and muscle function for walking. A training seminar was conducted at 12 rehabilitation facilities with 178 clinicians. Current practice, knowledge and barriers to exercise were assessed by observation and questionnaire prior to and immediately after the seminar, and at three-month follow-up. Additionally, post-seminar support and mentoring was randomly provided to half of the rehabilitation facilities using a cluster randomised controlled trial (RCT) design. The seminar led to significant improvements in clinician knowledge of the biomechanics of gait and resistance training, the amount of ballistic (t = -2.38; p = .04) and conventional (t = -2.30; p = .04) resistance training being prescribed. However, ongoing post-seminar support and mentoring was not associated with any additional benefits F(1, 9) = .05, p = .83, partial eta squared = .01. Further, improved exercise prescription occurred in the absence of any change to perceived barriers. The training seminar led to significant improvements in the time spent in ballistic and conventional resistance training. There was no further benefit obtained from the additional post-seminar support. The seminar led to improved knowledge and significantly greater time spent prescribing task-specific resistance exercises. [ABSTRACT FROM AUTHOR]

We seek to characterize the motility of mouse fibroblasts on 2D substrates. Utilizing automated tracking techniques, we find that cell trajectories are super-diffusive, where displacements scale faster than t1/2 in all directions. Two mechanisms have been proposed to explain such statistics in other cell types: run and tumble behavior with Lévy-distributed run times, and ensembles of cells with heterogeneous speed and rotational noise. We develop an automated toolkit that directly compares cell trajectories to the predictions of each model and demonstrate that ensemble-averaged quantities such as the mean-squared displacements and velocity autocorrelation functions are equally well-fit by either model. However, neither model correctly captures the short-timescale behavior quantified by the displacement probability distribution or the turning angle distribution. We develop a hybrid model that includes both run and tumble behavior and heterogeneous noise during the runs, which correctly matches the short-timescale behaviors and indicates that the run times are not Lévy distributed. The analysis tools developed here should be broadly useful for distinguishing between mechanisms for superdiffusivity in other cells types and environments. [ABSTRACT FROM AUTHOR]

Despite continued improvements in gunshot residue (GSR) detection and analysis, there are still challenges in the interpretation of GSR evidence. The level and distribution of GSR present on an individual can be influenced by many factors, dependent upon the context of any given case. Due and diligent attention must therefore be placed upon fate and behaviour processes in relation to GSR when assessing and interpreting any case findings. The distribution of GSR upon the body of a recreational shooter was assessed. Samples were taken from 17 positions across a shooter's body immediately after the discharge of one round of ammunition. The shooting hand prevailed as the most GSR-contaminated area, with as many as 351 characteristic GSR particles identified. The face and supporting hand also exhibited high levels of GSR contamination. This level of contamination raises questions concerning the fate and behaviour of GSR particles within the general environment, specifically with regard to transfer processes. [ABSTRACT FROM AUTHOR]

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, regardless of the action or loading type, DNA may be deposited onto the ammunition via touch. As reproducible DNA profiles have been obtained from fired cartridge casings and Improvised Explosive Device (IED) fragments, it is possible that quantifiable amounts of DNA could be recovered from fired bullets. A series of 40 Winchester PowerPoint 22LR 42 grain HP Copper Plated bullets were loaded with serially diluted cell suspensions obtained from a female donor. These were shot into 500 sheet reams of A3 paper for capture and returned to a sterile DNA laboratory for removal, extraction and quantification of DNA. Repeatable partial profiles with five reportable loci pairs consistent with the cell donor were obtained in one replicate of the neat sample. Weak partial profiles were also present in 1:2, 1:5 and 1:10 dilutions. To our knowledge, this is the first reported evidence of DNA surviving the cycle of fire and being recovered from a fired bullet under controlled conditions. [ABSTRACT FROM AUTHOR]

This project looks at the intersection between gunshot damage to road signs and the use of geographic information systems (GIS) for forensic intelligence. The project has surveyed several distinct regions in Victoria Australia (residential, semi-rural and rural) in order to establish the level and distribution of gunshot damage to signs. The study assesses the correlation between population densities, land use and road type and the types of gunshot damage associated with road signs. The study includes a temporal aspect with the aid of backdated GIS image data and assessment is made on the potential benefits for crime scene information gathering. Further, a software tool has been established that enables photographic analysis of the gunshot impact points to be used to help determine the scale of damage associated with the signs in order to help establish the types of weapons used. This information is presented in the context of the typical registered guns in the community to correlate the key types of weapons used in this type of activity. [ABSTRACT FROM AUTHOR]

Interior ballistics experiment is an indispensable link in the experimental teaching of weaponry in colleges and universities.Because of the risk of experimentation, the rapidity of the process, and the high cost of equipment, it is difficult to develop the interior ballistics in the actual teaching process. Taking the two typical experiments of projectile muzzle velocity test and rolling test as examples, the virtual reality technology was introduced into the traditional interior ballistics experiment, and an image and intuitive real-time virtual experiment scenario was established. The actual physical process was simulated through the calculation of interior ballistic simulation. Using the Unity3 D engine, an interior ballistic virtual experiment system with good visual immersion and interactivity has been developed. The teaching practice of the Weapons Virtual Simulation Experimental Teaching Center of North University of China shows that the internal ballistic virtual experiment system saves experimental expenses, improves the flexibility of time and space, and has good practical and promotional value. [ABSTRACT FROM AUTHOR]

Synthetic models, also called "surrogates", are commonly used in wound ballistics in order to simulate human tissues. Despite several surrogates are worldwide accepted and used; some of them have not been yet fully validated and their limits for forensic reconstructions have not been deeply investigated yet. In this work we present a homicide/suicide case involving three gunshots to the head with bullets retained in the skull or beneath the scalp. Reconstruction of these cases was performed preparing three individual synthetic head models based on post-mortem computed tomography (PMCT) measurements. Ballistic soap, polyurethane plates and 10% ballistic gelatine at 4°C were used as simulants in individually adapted thickness. Ballistic tests were performed using the questioned firearm and ammunition type. The damages on the synthetic models have been compared to the findings in PMCT and autopsy of the victims. Although the results highlighted general similarities in terms of injury characteristics, some of the experimental shots overpenetrated. Furthermore, the bullets recovered in the synthetic models did not show the same quality of deformations as the questioned bullets. This lack of bullet deformation in the synthetic models might be mainly attributed to the physical difference between real bones and polyurethane surrogate. [ABSTRACT FROM AUTHOR]

Triple base propellant (TBP) containing mainly nitrocellulose, nitroglycerine, and nitroguanidine has been manufactured and coated with plasticizer in the present work. The aim was to study ballistics of di-butyl phthalate (DBP)-coated TBP. DBP solution in ethanol containing nitrocellulose dope was used for coating onto the propellant grains. DBP-deterred propellant showed inhibition to burning, resulting in lowering the values of ballistic parameters namely peak pressure (Pmax), dPmax, pressure index (α), and burning rate coefficient (β) during closed vessel firing. Increase in percentage of DBP in coating solution led to further decrease in ballistic parameters. Dynamic evaluation of the surface-moderated propellant showed comparatively lower muzzle velocity and chamber pressure for deterred propellant batches without leaving any unburnt particles in gun chamber at subzero temperatures with the lowest possible charge mass. The DBP-coated propellant can be useful in 155-mm artillery gun to achieve higher loading density as it has lower flame temperature and chamber pressure as compared to uncoated propellant which will result in increasing barrel life due to reduction in the barrel erosion. [ABSTRACT FROM AUTHOR]

From time to time, severe or fatal injuries caused by small caliber air rifle projectiles are seen. In forensic sciences, the theoretical wounding potential of these weapons and projectiles is widely known. Usually, shots against the skull were reported and, in these cases, penetrating the eyes or thin bone layers of the temporal region. Amongst a huge number of different projectiles available for air guns, sub-caliber 4.4-mm (.173) caliber steel ball projectiles were used in an unusual suicide case. This case led to fundamental questions concerning wound ballistics. An 82-year-old man shot once against his right temporal region and twice into his mouth with a 4.5-mm (.177) caliber air rifle. Because of the exceptionally deep penetration of the base of the skull and the use of spherical-shaped sub-caliber air rifle projectiles, terminal ballistic features were analyzed and compared to results published in forensic literature. Test shots using the same weapon and similar projectiles were fired into ballistic gelatin to measure and calculate basic wound ballistic variables of cal. 4.4-mm (.173) steel balls. In comparison, further test shots with cal. 4.5-mm (.177) steel balls BB (ball bearing), flat-headed and pointed air rifle pellets ("diabolos") were carried out. The theoretical penetration depth in solid bone was calculated with 36.4 mm, and test shots in gelatin from hard contact produced an on-average wound track of 120 mm underlining the potential wounding effect. Furthermore, spherical projectiles could roll back and forth within the barrel, and an air cushion between projectile and breechblock can reduce muzzle velocity by more than half, explaining the retained missile in the temporal region. [ABSTRACT FROM AUTHOR]

A bystander claimed to have been shot by a police officer, and CT scans were used to match qualitative and quantitative aspects of the unremoved bullet with police issued 9 mm Luger ammunition. CT scan methodology proved a valid approach for the measurement of bullets based on calculated measurement capability and correlation with "gold standard" physical measurement by vernier caliper. Measurements regarding length and base diameter, as well as length/diameter ratio, were insufficient to unambiguously identify a specific caliber, or a bullet of specific mass within a caliber class. It was, however, possible to exclude a bullet of specific design and mass with well‐characterized precision and accuracy values under selected CT scan conditions. A 9 mm Luger bullet (115 gr FMJ RN) was excluded from involvement in a shooting based on qualitative bullet shape combined with length, base, and ratio measurements of the bullet in‐situ for the victim. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Highlights • Polymer composite armor from fiber-reinforced PBA as a strike panel is developed. • S glass/PBA panel can replace ceramic panel rendering lighter and safer hard armor. • The PBA composite armor shows ballistic impact resistance up to NIJ level III. • The ballistic limit of the composite panel based on ANSYS simulation is 930 m/s. Abstract The objective of this study is to measure impact performance of the composite based on glass and aramid fiber reinforced polybenzoxazine/polyurethane composites. Experimental panels were manufactured from E and S glass fiber reinforced polybenzoxazine backed by aramid fiber reinforced 80/20 polybenzoxazine/polyurethane and subjected to 7.62 × 51 mm at a velocity of 847 ± 9.1 m/s. Bases on test results the specimens did not have any perforation. Comparing the same number of ply, cone deformation on the last panel of S glass composite was significantly lower than that of specimen manufactured using E-glass composite. Such panels were tested for their resistance and the specimens completely resisted the penetration of projectiles for six shots. The numerical study of ballistic impact was undertaken to predict the ballistic limit velocity of the samples in which the value was measured to be 930 m/s. Results determined in this work indicated that such panels have an excellent ballistic characteristics to be used as raw material to manufacture body armor. [ABSTRACT FROM AUTHOR]

This article investigates abilities of university students in making assumptions in a ballistics model. The students were asked to make reasonable assumptions in a ballistics model often encountered in mechanics. The objects ranged from stones thrown by catapults in ancient times to launching projectiles and missiles from recent history. Students' responses to the questionnaire regarding their assumptions are presented and analysed in the article. [ABSTRACT FROM AUTHOR]

Abstract The vastly disparate length and time scales existing in new devices and materials born out of micro-/nano- devices have made thermal modeling and simulation more important and more difficult. The heat transfer process in one certain micro-device is essentially a thermal contact problem that involves various scales of space and time in each of the sub-components. In this communication, we utilize a newly developed computational framework to investigate problems of thermal contact involving size-effects that span the ballistic, ballistic-diffusive, and diffusive heat transfer processes. The preliminary work regarding this generalized computational framework has been published in Xue, Zhang, and Tamma (2018) and has been proved to readily resolve the problem of thermal contact between Fourier-type and nonFourier-type sub-domains. The fashion of solving the thermal inter-facial problems from the perspective of differential-algebraic equations is extended to a broad range of thermal contact problems in the present work, including both the temporal and spatial non-locality. The numerical results demonstrate the prediction of thermal response of the bodies in contact at different scales. The proposed computational framework paves the way for investigating the thermal inter-facial problems in micro-/nano- devices. [ABSTRACT FROM AUTHOR]

Structural and system reliability of a typical jet vane (JV) thrust vector control (TVC) subsystem subjected to stochastic loadings is investigated. Jet vane TVC (JVTVC) is used in many aerospace liquid and solid propulsion systems. For the purpose of this work, JVTVC structural reliability of a solid rocket propulsion system is computed using an explicit closed-form limit state function. The JV structure is influenced by the internal ballistic loads emanating out of the solid rocket propulsion internal ballistic, whose performance is modeled via a one-dimensional uniform flow assumption at the engine steady operating condition. Subsequently, JV structural reliability is predicted using the methods of mean value first-order second-moment as well as the first- and second-order reliability methods. The reliability results of the analytical methods are compared with Monte Carlo simulation for verification purposes. Finally, a comprehensive sensitivity analysis is performed to identify the key JVTVC and solid rocket propulsion design parameters affecting the TVC total system reliability. The parameters considered for sensitivity analysis include the JV geometric and structural properties as well as the solid rocket propulsion ballistic and geometric features. It turned out that the vane support arm radius and the vane area are the most important strength and load design variables, respectively, that impact the JVTVC failure reliability. [ABSTRACT FROM AUTHOR]

The conservation of the common buzzard is assured by the European Union law. In Poland, this wild bird is under strict species protection and it is used as a bioindicator for heavy metals in the environment. A case of the fatal shooting of a buzzard with a firearm by an unidentified shooter is described here. Macroscopic evaluation, X-ray imaging, post-mortem computed tomography, ballistic examination of the isolated bullets and finally a simulation of the assumed position of the bird at the time of the shot were performed. Numerous pellets were found inside the body, together with multiple bone fractures and central nervous system trauma. The buzzard died most probably as a result of spinal cord injury from a single shot that was fired from a smoothbore hunting gun. Collected evidence was insufficient to identify the shooter, which sadly confirms that identification of the perpetrator in wildlife forensics remains low. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Highlights • Cavity dynamics in gelatin was studied. • A motion model of temporary cavity is established in gelatin penetrations of rifle bullets. • The motion model is well consistent with the penetration tests. • The radial movement of cavity is characterized by the behavior of bullet and the characteristic velocity. Abstract In wound ballistics, modeling the penetration-cavitation dynamics will set the basis for evaluating the damaging efficiency of projectiles. In our previous study, a motion model to characterize the behavior of rifle bullets has been established and verified in the gelatin penetration. In order to reveal the cavity production analytically, in combination with parameters obtained from the motion model of rifle bullet, cavity dynamics in gelatin was studied and a motion model of temporary cavity in gelatin penetrations of rifle bullets was proposed and verified by comparison with experimental results in terms of maximum cavity wall radius, radial movement along the penetration trajectory and temporary cavity profiles. It can be concluded that calculated results of the cavity motion model agree well with experiment data for penetration of 7.62 mm and 5.56 mm rifle bullets. And the radial movement of cavity can be characterized by the behavior of bullet and the characteristic velocity. It is significant for the trauma assessment to develop an appropriate cavitation model in gelatin for penetrations of rifle bullet. [ABSTRACT FROM AUTHOR]

Highlights • Pressurized borosilicate glass cylinders were tested under high-velocity impact. • Efficiency of elastomeric coating on ballistic damage was investigated. • Drop tower testing was added to verify air gun results on the cylinders. • Critical coating thicknesses to prevent initiation of ballistic damage to porcelain bushings was estimated. Abstract Pressurized borosilicate glass cylinders were used to (1) simulate experimentally high-voltage transformer bushing behavior under high-velocity impact from an air gun, (2) investigate fragment dynamics to estimate the impact range of airborne fragments, and (3) evaluate the efficiency of an elastomeric coating on ballistic damage initiation and fragment confinement. Using high-speed cameras, the velocities and directions of ejected fragments from the cylinders were determined along with fragment distribution symmetry. Drop tower testing was added to independently verify the air gun results on the cylinders through a different test under similar impact energies using flat samples of the same glass. Elastomeric coatings were also applied to both the cylinders and flat samples to increase their resistance to high energy impact. It has been shown that internal pressure in the glass cylinders plays a major role in the failure modes during high-velocity impacts. This pressure affects velocities, directions, and symmetry of fragment distribution. The fragment impact range investigation turned out to be inconclusive due to highly erratic behavior of the fragments after the blast. Most importantly, it has been ascertained that fragment dynamics are drastically altered by elastomeric coatings, producing a high level of fragment confinement both in the drop tower and gun tests. By extrapolating the air gun and drop tower data out to high power rifle energy levels, unique predictions of the critical coating thicknesses to prevent the initiation of ballistic damage and to confine fragments in borosilicate glass cylinders and C-120 porcelain bushings were achieved for the first time. [ABSTRACT FROM AUTHOR]

According to hedonic pricing theory (HPT) market forces operate on individual characteristics of a good, and the price of a product is the aggregate of the price across those characteristics. The relationship between price and characteristics remains poorly understood because characteristic qualities are hard to quantify, people have varying levels of information about characteristics, and people have heterogeneous preferences over characteristics. By analyzing data from a large, market-driven virtual world we are able to test HPT, while largely avoiding these pitfalls. We find that a linear model with functional characteristics predicts the prices poorly, but a log-linear model performs quite well. Adding social characteristics to this log-linear model improves the predictions substantially. This work strongly supports HPT and demonstrates a “rational” calculus including social value. [ABSTRACT FROM AUTHOR]

Abstract Today, increasing energy demand and human consumption are becoming increasingly important for the safe use, storage and transport of energy resources. Energy sources have been the target of increasing terrorism and wars since the 20th century. In the future, alternative energy sources, such as hydrogen energy, are expected to take the place of fossil energy resources. This means that ballistic threats will target these resources. In this study, for the first time in the literature, the ballistic behavior of Type 1 metallic pressurized hydrogen storage tanks made of the 6061 T6 aluminum and SS304 stainless steel alloys at the different thicknesses against 7.62 mm were investigated under usage pressure. For these alloys, the minimum safe wall thickness of the hydrogen tank is mathematically calculated using finite element analysis. Highlights • The ballistic behavior of Type 1 metallic hydrogen storage tanks were analyzed. • The minimum safe wall thickness of the hydrogen tank was calculated. • For ballistic safety, the minimum thickness of Al 6061 T6 should be 42 mm. • For ballistic safety, the minimum thickness of SS 304 should be 22 mm. [ABSTRACT FROM AUTHOR]

The ability of a metallic surface layer to protect CFRP cross-ply plates against perforation is explored. Aluminium alloy plates (either AA1050A or AA6082-T6) were placed in front of a CFRP layer, and the bilayer was subjected to either quasi-static indentation or to ballistic impact by a spherical projectile, with rigid back support or an edge-clamped boundary condition. The observed perforation mechanism of the CFRP layer is neither influenced by the presence of the metallic layer nor by the choice of loading rate (i.e. quasi-static versus ballistic). In the back-supported condition, the CFRP layers fail by an indirect tension mode that consists of tensile failure of plies in the material directly beneath the indenter or projectile. Alternatively, in the edge-clamped condition, the CFRP layers fail by a shear plugging mechanism. Although the presence of metallic layers does not suppress the shear plugging of the underlying CFRP layer, the loaded area in the CFRP layer increases by the addition of the protective metallic layer, thereby increasing the perforation resistance of the CFRP layer. [ABSTRACT FROM AUTHOR]

Factors influencing effectiveness of automated comparisons, test‐fired bullets, and cartridge cases from 0.38 Special revolvers were logged into the Evofinder® Ballistic ID System. Tests were performed as follows: First test correlated test‐fires of the same type, second test compared different types of ammunition components, third test replicated the second test in a larger database, and fourth test replicated the third test with students having no previous firearm identification experience. System effectiveness with projectiles in the first test was 0.89. With cartridge cases, effectiveness was 0.79 with combined results, but analysis of separate results by breech face and firing pin revealed low effectiveness by breech face (0.40). In the second, third, and fourth tests, effectiveness with projectiles were 0.61, 0.51, and 0.44. In addition, these tests had effectiveness with cartridge cases equivalent to 0.55, 0.43, and 0.44. Results are useful to establish routine protocols, system improvements, or comparative assessment of other electronic systems. [ABSTRACT FROM AUTHOR]

The process of UUV delivery is a typical nonlinear transient dynamic phenomenon, which is generally described by the internal ballistic model. Evaluation of optimal internal ballistics parameters is a key step for promoting ballistic weapon performance under given launch constraints. Hence, accurate and efficient optimization techniques are required in ballistics technology. In this study, an artificial neural network (ANN) is used to simplify the process of regression analysis. To this end, an internal ballistics model is built in this study as a black box for a classic underwater launching system, such as a torpedo launcher, based on ANN parameter identification. The established black box models are mainly employed to calculate the velocity of a ballistic body and the torque of a launching pump. Typical internal ballistics test data are adopted as samples for training the ANN. Comparative results demonstrate that the developed black box models can accurately reflect changes in internal ballistics parameters according to rotational speed variations. Therefore, the proposed approach can be fruitfully applied to the task of internal ballistics optimization. The optimization of internal ballistics precision control, optimal control of the launching pump, and optimal low-energy launch control were, respectively, realized in conjunction with the established model using the SHERPA search algorithm. The results demonstrate that the optimized internal ballistics rotational speed curve can achieve the optimization objectives of low-energy launch and peak power while meeting the requirements of optimization constraints. [ABSTRACT FROM AUTHOR]

Directional gated imaging of hidden objects in scattering media is demonstrated using an ultrafast optical Kerr gate (OKG), in which the gating and imaging beams are focused by utilizing a cylindrical lens and a convergent lens, respectively. Owing to the spatial transmission characteristics of the directional gate, a rectangular aperture stop is formed, which leads to different resolution limits for vertical and horizontal structures of an object. By implementing directional gated imaging, the directional feature can be extracted from an original image. [ABSTRACT FROM AUTHOR]

Hypervelocity impact of a projectile on a thin plate generates a debris clouds. Largest chunk (mass) of the projectile material (called primary fragment) in the cloud poses significant ballistic threat to subsequent structure. Primary fragment characteristics (mass, velocity and exit angle) are used in assessing subsequent structure damage potential. Non-dimensional empirical equations are proposed in this paper for estimation of these characteristics. A set of simulations has been carried out using smoothed particle hydrodynamics (SPH) technique of Autodyn. Two stage light gas gun test data has been compared for validation of simulation. Simulation results for spherical projectile made of stainless steel impacting mild steel plate with impact velocity of 2–4 km/s and obliquity of 0°–60° has been analysed. Constants and radicals of the proposed equations are determined by multi variable regression of the simulation data. Comparison of the simulation data with the proposed equations shows a very good fit. [ABSTRACT FROM AUTHOR]

Modeling fiber-reinforced composites and fabrics in ballistic applications can be difficult after the initiation of damage and failure. Mesoscale models can provide accurate results, but they are much more computationally intensive than standard continuum approaches. However, an accurate continuum model for these materials requires a thorough understanding of the relevant deformation and failure mechanisms. A new continuum modeling approach was developed in which the average stresses and strains within a composite containing multiple fiber orientations are related at the element, lamina, and constituent length scales using rules of mixtures. The new approach was used to simulate a variety of mechanical and ballistic test data from different composite and fabric materials. The accuracy of the results demonstrates the predictive capability of the new model to reproduce deformation and damage of composites under generalized loading conditions. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Fingermark development techniques for brass cartridge cases/plates were evaluated. • The sequence CA + GB + fluorescent dye (BY40 or Ardrox) presented the best results. • The application of the entire sequence of developers is strongly recommended. • The gaseous blowback is the main firing effect on the deterioration of fingermarks. • Handling cartridges when loading a gun has a significant influence on the fingermarks. Abstract A study was undertaken wherein different fingermark developers were evaluated for the recovery of fingermarks from brass cartridge cases, besides the evaluation of factors such as firing effects and surface characterization of the cases. The latent fingermarks on α-brass plates, fired and unfired cartridge cases were deposited and aged for 1–14 days before development with different developers. In order to mimic the fired cartridge case conditions, the brass plates were heated and examined at room temperature (RT), at 63 and at 200 °C. The sequential treatment with cyanoacrylate, gun blue and fluorescent dye has been found to be the best among other developers for the recovery of latent fingermarks on brass surfaces including fired and unfired cartridge cases. Cartridge cases and other brass surfaces were also analyzed by surface characterization methods, including X-ray diffraction, scanning electronic microscopy, energy dispersive X-ray spectroscopy and metallographic examination. The tested surfaces correspond to α-phase brass Cu 0.7 Zn 0.3 composition and have shown different surface morphologies (such as grain structure) and different levels of oxidation, even for cartridge cases obtained from the same batch. Due to this, the effectiveness of a given reagent for a specific brass surface is uncertain. Therefore, the application of the entire tested sequence of developers is strongly recommended. Further, the effects of firing on fingermarks on cartridge cases were examined, and the results indicated that the blowback of hot gases through the looseness between cartridge case and chamber wall of the firearm is the main cause responsible for deterioration of fingermarks during firing. Despite the recognized damage caused to fingermarks by the firing effects, good quality fingermarks were recovered from fired cartridge cases in which full fingermarks were intentionally deposited prior to firing. This indicates that the handling of the cartridges before and during the loading of the gun may have a strong influence on the quantity and quality of fingermarks, and that the firing itself is not the main responsible factor for the absence or low quality of fingermarks, as frequently reported in fired cartridge cases studies. [ABSTRACT FROM AUTHOR]

Abstract: Three‐dimensional (3D) technologies contribute greatly to bullet trajectory analysis and shooting reconstruction. There are few papers which address the errors associated with utilizing laser scanning for bullet trajectory documentation. This study examined the accuracy and precision of laser scanning for documenting trajectory rods in drywall for angles between 25° and 90°. The inherent error range of 0.02°–2.10° was noted while the overall error for laser scanning ranged between 0.04° and 1.98°. The inter‐ and intraobserver errors for trajectory rod placement and virtual trajectory marking showed that the range of variation for rod placement was between 0.1°–1° in drywall and 0.05°–0.5° in plywood. Virtual trajectory marking accuracy tests showed that 75% of data values were below 0.91° and 0.61° on azimuth and vertical angles, respectively. In conclusion, many contributing factors affect bullet trajectory analysis, and the use of 3D technologies can aid in reduction of errors associated with documentation. [ABSTRACT FROM AUTHOR]

Firearm injuries are common in the world today, in both military and civilian settings. Research into the effects different ammunition has on the human body has been conducted using tissue simulants such as Ballistics Ordnance Gelatine. Previous research has found that with low velocity projectiles, the tissue simulants only represent a selected few organs, as the human body and its organs/tissues are not homogeneous. The aim of this research was to determine which ballistic simulants best represent the abdomen and thorax, for the purposes of anatomical modelling. A mounted firearm was used to fire specially made ammunition containing a sabot and steel spherical projectile at medium (∼500m/s) and high (∼900m/s) velocities. Test specimens of 50mm cube porcine tissues (lung, liver, kidney and heart) and ballistics simulants (20% and 10% Ballistics Gelatine and Clear Gel) were shot at and the energy loss determined using Doppler radar, optical infra-red sighting screens and high speed video. This study determined that the conclusions drawn from studies in these tissue simulants may not be an accurate representation of what occurs in human tissues and that different impact velocities produce differing results. New simulants are required to better represent the energy loss of a projectile through the organs of the abdomen and thorax and the results of this study may guide this development. Further experiments will be required to determine different concentrations of gelatine and their accuracy at representing the heterogeneous nature organs of the human body. [ABSTRACT FROM AUTHOR]

A description of a pistol (rifle) cartridge often involves two ballistic coefficients that characterize its ballistic qualities with respect to various air resistance laws (ARLs). How close are the obtained ballistic trajectories with varied ARL specifications and what are the differences between them? How to evaluate ballistics if the ARLs are to be expressed in various mathematical forms? In this paper, the evaluation of external ballistics trajectories is given for two ARLs (the law brought in 1943 and the Siacci law). All the obtained results relate to the TT pistol with 7.62 × 25mm Tokarev cartridge.The paper also presents the answer to the question: how to calculate the ballistic trajectory if the ARL is expressed as a rational function, piecewise function or spline. For the 1943 ARL, a graphical interpretation of the function Cd (i, v) in the form of a surface is shown. This paper shows that, due to the selection of ballistic coefficients, it is possible to obtain sufficiently similar form of ballistic trajectories. A method of graphical comparison of external ballistic parameters is presented as well as the mathematical tools for quantitative analysis of a shape of ballistic curves.The difference between the two trajectories is proposed to be estimated using a relative error in regard to а selected ballistic parameter. Computer simulation considered for the 1943 and Siacci ARLs for the 7.62×25mm Tokarev cartridge indicates that the profiles of the function of instantaneous projectile velocity vs time of flight (TOF) had the greatest non-coincidence in relation to other ballistic parameters (e.g. horizontal range, height of the trajectory, etc.) The obtained maximum of the relative error was 0.8%. Its magnitude localizes at the point of impact. [ABSTRACT FROM AUTHOR]

In this study, we present a numerical model to simulate the ballistic impact of a rigid right circular cylinder (RCC) projectile into a woven fabric target. The numerical solution of transverse ballistic impact on a laminar biaxial fabric is obtained using a forward finite-difference method. The ballistic impact analysis for different materials of targets made of aramid and polyethylene fibers are simulated to investigate the effect of fabric material on the ballistic resistance. Numerical simulations are performed to reveal the influences of crimp factor and fabric material on the ballistic performance of woven fabrics. Various cases have been presented showing the variations of yarn strains, yarn velocities, and yarn displacements over time. [ABSTRACT FROM AUTHOR]

The UK Home Office test method for ballistic protective police body armours considers anterior torso impacts to be the worst-case scenario and tests rear armour panels to the same standards as front panels. The aim of this paper was to examine the injuries from spinal behind armour blunt trauma (BABT) impacts. This study used a cadaveric 65 kg, female pig barrel and 9 mm Luger ammunition (9 × 19 mm, FMJ Nammo Lapur Oy) into HG1/A + KR1 soft armour panels over the spine. Injuries were inspected and sections removed for x-radiography and micro-CT assessment. All shots over the spine resulted in deep soft tissue injuries from pencilling of the armour and the shirt worn under the armour. The wounds had embedded fabric debris which would require surgery to remove resulting in increased recovery time over injuries usually seen in anterior torso BABT impacts, which are typically haematoma and fractured ribs. The shot with the deepest soft tissue wound (41 mm) also resulted in a fractured spinous process. Shots were also fired at the posterior and anterior rib area of the pig barrel, for comparison to the spine. Similar wounds were seen on the shots to the posterior rib area while shallower, smaller wounds were seen on the anterior and one anterior rib shot resulted in a single, un-displaced rib fracture. The anatomical differences between pigs and humans would most likely mean that injury to a human from these impacts would be more serious. [ABSTRACT FROM AUTHOR]

Discusses the influence of resonant multi-mode pumping has on a coherent far infrared field within a ballistic quantum channel. Characterizing of frequencies of the mode spectrum; Expectancy of the Rabi oscillations; How these oscillations are exploited.

Presents information discussing the space charge limited ballistic electron transport through double quantum well segments. Simulation of three different structures; How the anode currents in the structures oscillate; Increasing of the space charge.

Shows the resonant interaction of electrons in a quantum ballistic channel with a strong electromagnetic field. Photoconductance of quantum point contact; Spatial modulation of the charge distribution; Emergence of Rabi oscillations in the mode population; Proposed used of an array of gates to simulate a moving quantum contact.

A MoS2 sheet in its 1T ' phase is a two-dimensional topological insulator. It possesses highly conductive edge states which, due to topological protection, are insensitive to back scattering and are suitable for device channels. A transition between the topological and conventional insulator phases in a wide 1T '-MoS2 sheet is controlled by an electric field orthogonal to the sheet. In order to enhance the current through the channel several narrow nanoribbons are stacked. We evaluate the subbands in a narrow nanoribbon of 1T '-MoS2 by using an effective k ∙ p Hamiltonian. In contrast to a wide channel, a small gap in the spectrum of edge states in a nanoribbon increases with the electric field. It results in a rapid decrease in the nanoribbon conductance with the field, making it potentially suitable for current switching. [ABSTRACT FROM AUTHOR]

"High School and Undergraduate Physics Practicals with 3D Simulations" is a monograph written by Robert Lucas and published by CRC Press in 2022. The book provides a comprehensive collection of 34 physics experiments for high school and undergraduate students, along with background information and instructions on how to carry out each experiment. It also includes 3D simulations of the experiments for students who do not have access to a real laboratory. The book is written in a clear and concise manner and is aimed at students, lecturers, and researchers in the field of physics. It is recommended for those looking to enhance their experimental skills and broaden their knowledge in the subject. [Extracted from the article]

[Display omitted] This study aims to identify the ballistic mechanisms of quasi-isotropic (QI) panels made from compliant composite laminates, focusing on the propagation of various stress waves. Three hypotheses are proposed that in terms of the propagation of stress waves, incorporating ① longitudinal, ② transverse, and ③ bending waves, QI panels would perform better than the aligned (AL) counterparts, based on simplified theoretical analyses to provide a theoretical basis for the study. 2-, 3-, and 4-ply QI panels are found to absorb approximately 23 % more energy than the aligned (AL) counterparts in the ballistic tests. The finite element (FE) models are developed using hierarchical and global-local approaches, and the results are well agreed with the experimental ones. The results elucidate the influence of QI stacks on the propagation of stress waves. The ballistic mechanisms are ultimately explored and elucidated. [ABSTRACT FROM AUTHOR]

• Ballistic, a high strain-rate method, used to produce functionally graded materials. • Hardness and microstructures are studied as functional properties. • Axisymmetric & unsymmetrical variation can be achieved. • The variation can be controlled by the leading edge shape, speed, & target material. In the present effort, impact of bullets fired at high speeds on a stationary target was used as a high strain-rate plastic deformation method to generate Functionally Graded Materials (FGMs). The bullet-shaped Aluminum alloy Al5052 specimens impacted the UHMWPE target at different projectile velocities ranging from 100 m/s to 750 m/s, to study the effect of the impact speed. Moreover, few of the projectiles impacted along the longitudinal axis whereas the remaining projectiles impacted with an obliquity to investigate the effect of leading-edge shape. The metallography of the projectile specimens fired at 750 m/s shows grain refinement from 70 ± 3 μm at the rear/ un-deformed point to 10 ± 1 μm at the front/ severely deformed point which is in the impact zone. Similar but of less magnitude variations were observed at other impact speeds also. The hardness variation was 45% (70 ± 3 HV at the rear surface to 102 ± 2 HV at the front face) at 750 m/s. Moreover, least variation in hardness and grain size was observed for projectile impacted at lowest velocity tested (100 m/s). Further, functionality in hardness and grain refinement was seen in graded direction due to shape of the projectile specimens, impact velocity, and target material. Depending upon the impact angles, axisymmetric (impacted normal to the longitudinal axis) or unsymmetrical (impacted at an angle) variation of grain refinement and hardness was observed. [Display omitted] [ABSTRACT FROM AUTHOR]

Keywords: Olympic archery; shaft; recurve bow; ballistics EN Olympic archery shaft recurve bow ballistics S526 S528 3 01/29/21 20191002 NES 191002 1. When the archer reaches full draw, potential elastic energy (Graph HT ht ) is stored in the bow limbs. [Extracted from the article]

The ballistic mobility degradation is shown to originate from nonstationary (transient) transport in response to the ohmic electric field. The source and drain reservoirs launch electrons into the channel with injection velocity transiting the channel with finite ballisticity defined as the probability of a collision-free flight. The distinction is made between the ballistic mean free path and that present in a long channel. The results are in excellent agreement with those obtained from Monte Carlo procedures and experiments. [ABSTRACT FROM AUTHOR]