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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.

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.

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

This paper proposes a cost-effective, compact, noncontacting optoelectronic targeting system for measuring the distribution of projectile motion. The major elements of this system include a light emitting diode (LED) array, photodiode detecting array, double-layered aperture arrays, adaptive threshold circuit, and date acquisition. Through cooperating with double-layered aperture arrays, the system effectively reduces the radiation width of the light source to the photodiode detecting surface, and filters out the influence of incident light from the adjacent apertures on both sides above each photodiode to the corresponding photodiode detecting surface. It realizes that the response of the photodiode array corresponds to the coordinates of the light screen one by one. Through the sensitivity analysis of the light screen of the system, the system detecting threshold when the projectile passes through the light screen is calculated, and the corresponding adaptive threshold circuit is designed to prevent misjudgment when the system works. The measuring error of the system can reach &plusmn, 2 mm by experimental verification. Compared with other projectile&rsquo, s distribution measuring systems, the proposed system has the advantages of having high precision, convenient debugging, is nondestructive, and is a noncontact system.

John Durham Peters invites a rethinking of the optical and environmental duality of the screen by examining media practices that link projection to protection and showing to shielding. The ontological ambiguity of the screen—at once a site for the representation of a world and a real element embedded in the world—enables one to think of media as a key part of what Peters calls ‘infrastructures of being’. Outlining the historical convergences between cultural practices of targeting and visualizing in Western history, Peters weaves together a rich and unexpected set of voices from the onset of the ‘atomic age’—from James Joyce and Vladimir Nabokov to Harold Edgerton and Norbert Wiener—illuminating the connection of detonation to image-making across photographic, filmic, televisual, and celestial screens.

In this study, we examined the aerodynamic loading on a small caliber rifle (spin stabilized) projectile moving in a muzzle flow field using an element method to analyze the loading and the effect of the angle of attack (for small angles from 0 to 3 deg) on the different components. The temporal pressure distribution on the projectile, which forms the basis of the element method, was computed using a computational fluid dynamics (CFD) analysis combined with a classical interior ballistics model. Then, a high-speed optical experiment was conducted to verify the results of the CFD method and ensure the accuracy of the calculations. The results were as follows: (a) similar to a large caliber projectile, the total axial force, which consisted primarily of the axial forces on the base and boattail, was found to have an inverse exponential relationship with time; (b) the overall lift was a combination of the lift of the base, boattail, cylinder, and nose; and (c) the interaction between the pitch moment of the base and that of the boattail was found to be the primary contributing factor to the total pitch moment. Based on these results, we recommend that the characteristics of the base and boattail be considered when specifying the geometric configuration of a projectile.

A mathematical-physical model of the hypersonic anti-tank kinetic subcalibre projectile for 120 mm munition was built. Computer simulations of the projectile flight were performed for any angle of shooting, from 0° to 90°. Trajectories of projectile flights were determined considering all angles of shooting. Theoretical calculations were verified by experimental measurement of the projectile velocity in time while shooting on a test range. Some conclusions with regard to safety during hypersonic projectile shooting on the test range were formulated.

Background: Methods for describing physics of impact and ballistics have been developed over a number of decades. These include analytical mathematical representations as well as modern computer simulations.

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 (

A method is presented to be used in a computational experiment aimed at studying the internal structure of nano- and mesoscopic objects, i.e., conducting subsystems and quantum phenomena in solid submicron objects, which demonstrate an individual behavior of low-temperature resistance.

The development of high accuracy rifle has uncovered a need for understanding the movement of the bullet in muzzle flow. Recent researches have always been focused on computational fluid dynamics (CFD) and experimental research on the muzzle flow, which released many data, such as velocity and base pressure drop of projectile. Due to CFD tests are timeconsuming, a dynamic model for spatial motion of projectile is established. In this model an empirical relationship is utilized for the base pressure of projectile, and the model is assumed that the base pressure is along the axis of barrel which applied on the tail cone of the bullet; The spatial motion equations deduced from the mass center motion equations and Euler equations of motion are solved with Runge-Kutta method. A 7.62 caliber bullet is tested to verify the dynamic model. The result agrees with the CFD and experimental data, which shows that the model is applicable in predicting the translational motions, besides the angular motion of projectile is also presented, which can be the initial condition of exterior ballistics to analyses the firing accuracy.

The main objective of this work is to assess the pressure levels obtained over a new designed 155 mm/52-calibre gun-howitzer during a firing sequence. For this design, the barrel muzzle exit is really close to the truck driver’s cab. It is then essential to verify that the wall pressure levels resulting from an artillery firing are compatible with the considered material. For this purpose, the CFD ballistics code FREIN 3D is used to compute the direct coupling between interior, intermediate and exterior ballistics of this new 155 mm/52- calibre gun-howitzer. A simplified geometry is considered for the CFD computation and the computational domain involves only a part of the truck chassis since only the pressure levels over the first part of the truck are of interest. One case is considered, corresponding to an indirect firing.

Purpose: Aging is associated with slow reactive movement generation and poor termination.Objective: We examined the hypothesis that the build-up of excitability in the primary motor cortex in the agonist muscle to generate ballistic wrist flexion and extension and in the antagonist to stop the movement, is lower and slower in old compared with young adults.Methods: We measured the size of the motor potentials evoked (MEP) produced by transcranial magnetic stimulation (TMS), background integrated EMG (iEMG), and the MEP: iEMG ratio in healthy young (23 y, n = 14) and old adults' (73 y, n = 14) wrist flexors and extensors as they rapidly flexed or extended the wrist in response to an auditory cue. TMS was delivered at 80% of resting motor threshold randomly in 20 ms increments between 130 and 430 ms after the tone.Results: Even though old compared to young adults executed the two wrist movements with similar to 23% longer movement duration and similar to 15% longer reaction time (both p Conclusion: These data suggest that an adjustment of current models might be needed to better understand how and if age affects the build-up excitability accompanying movement generation and termination.

Objective To evaluate the learnability and feasibility of a new technique comprising a needle-guidance-system (NGS) for ultrasound-assisted lumbar puncture. Method Using a randomized crossover study design, 24 medical students were asked to perform an ultrasound-assisted lumbar puncture on a gel phantom using two different techniques that each included a paramedian insertion site. Procedure 1 (P1) used a pre-procedural ultrasound scan to predetermine the ideal insertion point. Procedure 2 (P2) applied a new technique comprising an NGS for performing real-time ultrasound-guided lumbar puncture. Success rates and performance times for both procedures were compared. Participants were also asked to complete a post-study questionnaire, both to quantitatively assess the workload involved and state their personal preferences. Results In comparison to the pre-procedural scan (P1), the NGS (P2) was associated with a significant increase in the number of successful punctures per participant (5 (P2) [interquartile range: 3.3–5.0] vs. 3 (P1) [interquartile range: 1.3–4.0], p = 0.005), and led to a significant reduction in performance time (118 seconds vs. 80.6 seconds, p < 0.001). In terms of workload perception, NGS use was associated with significantly better performances and lower frustration levels, as rated by students in the post-study questionnaire. Finally, 23/24 participants stated their preference for P2. Conclusion Our newly-developed technique for real-time ultrasound-guided lumbar puncture proved to be learnable and feasible for novices, and only required a small amount of training. The use of an NGS therefore has the potential to serve as a key feature of the ultrasound-assisted lumbar puncture.

Multi-dimensional multi-component two-phase flow modeling of solid propellant combustion in weapons is the new trend of the interior ballistics codes. Most of these codes are designated to large caliber guns and rockets simulation. Only a small number of investigations on small-caliber gun have been recently reported, where the need of high-performance and reliable small-caliber guns stimulated significant interest in developing techniques to understand the phenomenology of small-caliber ballistics and predict the behavior and the performance of this type of weapons. In this paper, a numerical model describing the combustion of solid propellant in small-caliber gun is presented. The governing equations with customize parameters were derived in the form of coupled, non-linear axisymmetric partial differential equations. They were further implemented into the CFD code Fluent. A numerical test showed that Fluent is able to handle correctly the interaction between the moving projectile and the combustion gases in the chamber. The interior ballistics curves along with the performance of small-caliber gun 5.56 mm were adequately predicted. The numerical results were in agreement with the experimental results.

OBJECTIVE: The purpose of this meta-analysis was to study the short-term adaptations on sprint and vertical jump (VJ) performance following Complex Training (CT) in team-sports. CT is a resistance training method aimed at developing both strength and power, which has a direct effect on sprint and VJ. It consists on alternating heavy resistance training exercises with plyometric/power ones, set for set, on the same workout. METHODS: A search of electronic databases up to July 2016 (PubMed-MEDLINE, SPORTDiscus, Web of Knowledge) was conducted. Inclusion criteria: 1) at least one CT intervention group; 2) training protocols ≥4-wks; 3) sample of team-sport players; 4) sprint or VJ as an outcome variable. Effect sizes (ES) of each intervention were calculated and subgroup analyses were performed. RESULTS: A total of 9 studies (13 CT groups) met the inclusion criteria. Medium effect sizes (ES) (ES = 0.73) were obtained for pre-post improvements in sprint, and small (ES = 0.41) in VJ, following CT. Experimental-groups presented better post-intervention sprint (ES = 1.01) and VJ (ES = 0.63) performance than control-groups. SPRINT: large ESs were exhibited in younger athletes (12 total sessions (ES = 0.74). VJ: Large ESs in programs with >12 total sessions (ES = 0.81). Medium ESs obtained for under-Division I individuals (ES = 0.56); protocols with intracomplex rest intervals ≥2 min (ES = 0.55); conditioning activities with intensities ≤85% 1RM (ES = 0.64); basketball/volleyball players (ES = 0.55). Small ESs were found for younger athletes (ES = 0.42); interventions ≥6 weeks (ES = 0.45). CONCLUSIONS: CT interventions have positive medium effects on sprint performance and small effects on VJ in team-sport athletes. This training method is a suitable option to include in the season planning. Actividad Física y Deporte

High-speed videos of blood spatter due to a gunshot taken by the Ames Laboratory Midwest Forensics Resource Center (MFRC) [1] are analyzed. The videos used in this analysis were focused on a variety of targets hit by a bullet which caused either forward, backward, or both types of blood spatter. The analysis process utilized particle image velocimetry (PIV) and particle analysis software to measure drop velocities as well as the distributions of the number of droplets and their respective side view area. The results of this analysis revealed that the maximal velocity in the forward spatter can be about 47±5m/s and for the backward spatter - about 24±8m/s. Moreover, our measurements indicate that the number of droplets produced is larger in forward spatter than it is in backward spatter. In the forward and backward spatter the droplet area in the side-view images is approximately the same. The upper angles of the close-to-cone domain in which droplets are issued in forward and backward spatter are, 27±9° and 57±7°, respectively, whereas the lower angles of the close-to-cone domain are 28±12° and 30±18°, respectively. The inclination angle of the bullet as it penetrates the target is seen to play a large role in the directional preference of the spattered blood. Also, muzzle gases, bullet impact angle, as well as the aerodynamic wake of the bullet are seen to greatly influence the flight of the droplets. The intent of this investigation is to provide a quantitative basis for current and future research on bloodstain pattern analysis (BPA) of either forward or backward blood spatter due to a gunshot.

A computational thermofluid-dynamic model of hybrid rocket internal ballistics is developed. Numerical simulations of the flowfield in a laboratory small-scale hybrid rocket motor, operated with gaseous oxygen and high-density polyethylene propellants, are carried out with the aim of predicting the solid fuel regression rate experimentally achieved with two different oxidizer injectors. The fuel regression rate is the main parameter for the hybrid rocket design. Here, it is calculated with a detailed gas/surface interface characterization based on local mass and energy balances. The combustion of oxygen and gaseous ethylene injected from the fuel wall is modeled by means of the probability-density-function approach coupled to chemical equilibrium. Two oxidizer-injection configurations, which generate either a two-dimensional axially symmetric or three-dimensional flowfield, are analyzed. The local regression rate is evaluated along both the fuel grain axis and inner circumference in the three-dimensional case, as well as at several stages in the firing, by updating the local port diameter, which is thus not assumed constant. Data retrieved from three firing tests are compared with the numerical results, revealing good agreement between both the average regression rates (maximum deviation less than 5%) and the fuel consumption axial profiles (with maximum deviation of 14%)

A two-channel infrared (1.55 μm) laser interferometer intended for measuring velocities of free surfaces in shock-wave experiments is described. Characteristics of the device and comparison results with the VISAR interferometer are given. A combination of Photonic Doppler Velocimetry (PDV) and PDV-Pivot interferometric schemes allows one to implement operation in four different modes and efficiently use capabilities of up-to-date digital oscilloscopes. A 4-GHz bandwidth oscilloscope enables one to measure velocities in a range of 0–6 km/s. The proposed interferometer is efficient for studies of the properties of structural materials, inner ballistics, detonation kinetics, and projectile ability of explosives.

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.

The U.S. Army AMRDEC has been performing research focusing on both analytical modeling and obtaining validation data through experimentation. The focus of this research is to understand both the impact event, and the associated material damage mechanisms. A key aspect of weather encounter modeling is that the local vehicle flow field environment alters the impact boundary conditions with time. Therefore, an analytical model must be able to include not only the vehicle flow field, but also the time accurate embedded flow field surrounding the droplets as they alter shape prior to impact. The impact event is highly dependent on the actual droplet shape at impact, and therefore extensive modeling and testing was required to obtain data suitable for code validation. The empirical testing effort consisted of single droplet impacts, high-speed rocket sled testing, and testing in a ballistics range. The data presented focuses on the data collected at the ballistics range for Mach numbers ranging from 2 to 7 for various shapes. The core analytical effort was developed by extensive modifications of the Smoothed Particle Hydrodynamics C-Code (SPHC) from Stellingwerf Consulting, augmented with an improved water equation of state that included the supercooled regime to augment the fidelity of the impact physics for rain drops at high altitudes. The analytical model demonstrates that the temporal distortion of water in a post-shock environment and the impact events for various projectiles can be captured with reasonable accuracy. The next step is to obtain data within the shock layers of relevant vehicle shapes in order to obtain the detailed demise and coupled flow field physics in order to validate the model in a realistic environment. The data presented reveals the droplet shape change and demise characteristics inside the shock structures for missile domes and sphere-cone designs, along with the complex embedded shock structure and impact physics associated with these events. This data forms a subset of empirical data that can be used for the fully-coupled full-scale impact events on flight vehicles.

High frame-rate imaging is a valuable tool for non-destructive evaluation (NDE) as well as for ballistic impact studies (terminal ballistics), in-flight projectile imaging, studies of exploding ordnance and characterization of other high-speed phenomena. Current imaging systems exist for these studies, however, none have the ability to do in-barrel characterization (in-bore ballistics) to image kinetics of the moving projectile BEFORE it exits the barrel. The system uses an intensified high-speed CMOS camera coupled to a specially designed scintillator to serve as the X-ray detector. The X-ray source is a sequentially fired portable pulsed unit synchronized with the detector integration window and is able to acquire 3,600 frames per second (fps) with mega-pixel spatial resolution and up to 500,000 fps with reduced pixel resolution. This paper will discuss our results imaging .30 caliber bullets traveling at ~1,000 m/s while still in the barrel. Information on bullet deformation, pitch, yaw and integrity are the main goals of this experimentation. Planned future upgrades for imaging large caliber projectiles will also be discussed.

Bullets striking common forms of flat glass with an orthogonal intercept angle result in a cloud of ejected glass fragments that are in concert with the exiting bullet's flight path. This is not the case with strikes at angles other than orthogonal. In these situations, the expelled glass fragments follow a very different course from that of the exiting projectile. This is both counterintuitive and a potential source of serious error in the evaluation and reconstruction of a shooting victim's position and orientation at the moment the victim was struck by a bullet that has passed through a nearby source of glass such as a vehicle side window or a window in a building. The flight path of the ejected glass fragments is, however, predictable and is dictated by the orientation of the plane of the glass opposite the projectile's impact site.In all cases, these expelled glass particles have considerable velocity and can produce pseudostippling of the skin in individuals located downrange of bullet-struck glass and near the projectile's exit site. The distribution and location of such pseudostippling and its relationship to the associated bullet hole in glass have important reconstructive value. A proper and reliable reconstruction of the victim's position in such cases will require the integration of scene information with the autopsy findings.

Radar is assumed to be tracking a cannon launched projectile travelling in a 2 dimensional drag environment. Extended Kalman Filter (EKF) is explored for the estimation of position and velocity of the projectile. Simulation is carried out using MATLAB and the results are presented. Finally, based on the results, EKF is recommended for tracking the projectile.

In the shadow photograph system in ballistics range, the exposure time of the CCD cameras is a very important parameter. The method to measure the accurate exposure time of the CCD camera is suggested based on the short pulsed laser source, timing sequence control system, high speed photo- detector and oscilloscope with the precision of 0.1μs. This method solved the problem of no effective measurement method with high precision for this parameter. The accurate minimum exposure time of IGV-B4820 of company Imperx was tested by this method successfully.

Geometrically similar scaling is applied to various blast loading experiments and the results are reported. The geometry of the experiment was scaled by a single scale factor. The imparted impulse (captured by the horizontal motion of a pendulum), mid-point deflections of thin plates and an estimate of the strain rates are compared relative to the observed and geometrical scale factors. The analysis confirms the similarity of the imparted impulse obtained and indicates the importance of material properties such as yield strength and strain rate sensitivity on the similarity of the mid-point deflections.

Basic concepts and algorithms laid as foundations of the scheme of landing on the Martian moon Phobos (developed for the Phobos-Grunt project) are presented. The conditions ensuring the landing are discussed. Algorithms of onboard navigation and control are described. The equations of spacecraft motion with respect to Phobos are considered, as well as their use for correction of the spacecraft motion. The algorithm of estimation of the spacecraft’s state vector using measurements with a laser altimeter and Doppler meter of velocity and distance is presented. A system for modeling the landing with a firmware complex including a prototype of the onboard computer is described.

A new computational approach is developed to predict the impact behaviour of fabric panels based on the detailed response of the smallest repeating unit (unit cell) in the fabric. The unit cell is constructed and calibrated using measured geometrical (weave architecture, crimp, voids, etc.) and mechanical properties of the fabric. A pre-processor is developed to create a 3D finite element mesh of the unit cell using the measured fabric cross-sectional micro-images. To render an efficient method for simulation of multi-layer packs, these unit cells are replaced with orthotropic shell elements that have similar macroscopic (smeared) mechanical properties as the unit cell. The aim is to capture the essence of the response of a unit cell in a single representative shell element, which would replace the more complicated and numerically costly 3D solid model of the yarns in a crossover. The 3D finite element analysis of the unit cell is used to provide a baseline mechanical response for calibrating the constitutive model in the equivalent shell representation. This shell element takes advantage of a simple physics-based analytical relationship to predict the behaviour of the fabric's warp and weft yarns under general applied displacements in these directions. The analytical model is implemented in the commercial explicit finite element code, LS-DYNA, as a user material routine (UMAT) for shell elements. Layers of fabric constructed from these specialized elements are stacked together to create fabric targets that are then analysed under projectile impact. This approach provides an efficient numerical model for the dynamic analysis of multi-layer fabric structures while taking into account several geometrical and material attributes of the yarns and the fabric.

In the experiment SIGNAL, which is planned to take place on board spacecraft INTERHELIOPROBE, a xenon gammaray spectrometer is to be used. The gamma-ray spectrometer in question has been chosen because of its characteristics permitting detailed study of solar gamma-radiation under rough experimental conditions. The equipment is able to provide: high energy resolution (5-6-fold better than that of scintillation detectors), performance at high temperatures, steady operation under significant vibroacoustic load, and high radiation resistance of the working medium. The aforesaid properties of the xenon gamma-ray spectrometer meet goals and objectives of the experiment SIGNAL. The description of ballistics scenario and operation orbit of the INTERHELIOPROBE spacecraft (SC) are presented.

We propose the use of “characteristic length,” based on radar cross section, as a metric for comparing the performance of orbital debris impactors of differing shapes, and the use of NASA's standard breakup model (SBM) “flake” shape as the representative particle for predicting orbital debris penetration effects. We also propose the use of a 26-view methodology for examining non-spherical particles such as cylinders, rectangular prisms, octahedrons, etc., with the intent to describe their potential impact orientations while minimizing the number of hydrocode runs needed to develop orientation-dependent ballistic limit curves. Using this methodology and the smooth particle hydrodynamic code (SPHC), we predict the ballistic limit for SBM-based particles against a typical spacecraft dual-wall shield at normal obliquity and velocities of 7, 8, and 12 km/s. Finally, we compare these results with ballistic limits produced by spherical impactors of the same characteristic length as the SBM-based particles.

The Integrated Ballistics Identification Systems (IBIS) is widely used for bullet and casing signature identification. The IBIS obtains a pair of ballistic signatures from two bullets (or casings) using optical microscopy, and estimates a correlation score which can represent the degree of signature match. However, this method largely depends on lighting and surface conditions because optical image contrast is primarily a function of test surface`s slope, shadowing, multiple reflections, optical properties, and illumination direction. Moreover, it can be affected with surface height variation. To overcome these problems and improve the identification system, we used well known surface topographic techniques, such as confocal microscopy and white-light scanning interferometry. The measuring instruments were calibrated by a NIST step height standard and verified by a NIST sinusoidal profile roughness standard and a commercial roughness standard. We also suggest a new analysis method for the ballistic identification. In this method, the maximum cross-correlation function CCFmax is used to quantify the degree of signature match. If the compared signatures were exactly the same, CCFmax would be .

At our university, students in introductory physics classes perform a laboratory exercise to measure the range of a projectile fired at an assigned angle. A set of photogates is used to determine the initial velocity of the projectile (the launch velocity). We noticed a systematic deviation between the experimentally measured range and the range calculated using the speed as determined by the photogates. In this paper, we will discuss the origin of this systematic error and derive a simple formula to correct it. In particular, we find that the launch speed given by our instrument is significantly different from the actual launch speed of our projectile.

The deviation of bullets passing through window pane glass of a thickness of 6 mm was investigated for varying angles of incidence. Projectiles of calibre 0.22 and 0.38 (wadcutter) were used. The 0.22 bullets break into multiple pieces, resulting in a large distribution of exit angles. An increasing deviation of 0.38 wadcutter projectiles was seen for increasing angles of incidence. For incident angles larger than 35°, an unexpected ricochet was noticed. This phenomenon is of importance when examining crime scenes. A number of parameters which have to be taken into account for further experiments is suggested.

Gun violence continues to be a staggering and seemingly intractable issue in many communities. The prevalence of gun violence among the sub-population of individuals under court-ordered community supervision provides an opportunity for intervention using remote monitoring technology. Existing monitoring systems rely heavily on location-based monitoring methods, which have incomplete geographic coverage and do not provide information on illegal firearm use. This paper presents the first results demonstrating the feasibility of using wearable inertial sensors to recognize wrist movements and other signals corresponding to firearm usage. Data were collected from accelerometers worn on the wrists of subjects shooting a number of different firearms, conducting routine daily activities, and participating in activities and tasks that could be potentially confused with firearm discharges. A training sample was used to construct a combined detector and classifier for individual gunshots, which achieved a classification accuracy of 99.4 percent when tested against a hold-out sample of observations. These results suggest the feasibility of using inexpensive wearable sensors to detect firearm discharges.

This paper provides equations describing the ballistic performance capability of meteoroid/orbital debris (M/OD) shield systems employed on the International Space Station (ISS). Hypervelocity impact (HVI) tests and analysis were used in developing the semi-empirical ballistic limit equations (BLE). A description of each type of shield system, HVI tests and analysis performed to assess shield performance, and ballistic limit equations that define the protection capability of the shield are given. Methods to improve the performance of spacecraft shielding are also discussed.

The most important research results and the prospect directions for the electromagnetic (EM), electrothermal (TT) and electrothermochemical (ETC) launch in Russia are presented in this paper. The development of pulse power supplies, materials, projectile ballistics and simulation is also considered.

An analysis is made of the optimal conditions for laser irradiation and of typical paths of man-made debris in laser-reactive protection of spacecraft. Protection is provided by the recoil momentum resulting from laser evaporation of the surface layers of a debris particle, which can change its path, thus avoiding an collision with a spacecraft. Estimates are obtained of changes in the paths of particles with a characteristic size 1 cm when they are irradiated by radiation from a laser located on the protected spacecraft moving along one of the circular orbits at altitudes of 200, 400, or 700 km above the Earth's surface.

The paper describes a unique measurement facility allowing research to be undertaken into the dynamics of an ensemble of spheres (shot cloud) evolving in time and space. The acoustoelectronic ballistics target produces accurate timing and positional information on the distribution of the spheres in a shot cloud, typically at transonic velocities. The ballistics target also allows graphical reproduction of the shot cloud outline in three dimensions.

Using a two-color ultrafast surface deflection spectroscopy, we demonstrate the time-resolved observation of acoustic phonon wave packets emitted from a single buried GaAs quantum well. A longitudinal acoustic phonon pulse is generated at a preselected depth within a highly confined region ( $\ensuremath{\ge}10\mathrm{nm}$ thick) through the coherent nonequilibrium deformation potential which was previously unobserved in such structures. Subsequent detection with subpicosecond resolution at the surface resolves propagating high-wave-vector ballistic phonons and quasiballistic or ``snake'' phonons which subsequently merge into a quasidiffusive phonon pulse.

A method for accelerating particles which can be used in delivering genes into living cells is described. By inducing a one-dimensional elastic strain wave impulse in a fixed solid plate, the micron particles adhered to the center of the plate’s free surface can be accelerated to a velocity up to a few tens of meters per second. Two schemes have been devised in which the impulsive waves were generated by mechanical collision and by a piezoelectric transducer, respectively. Their principles are outlined and the initial velocities of particles are analyzed. The collision scheme has been tested experimentally for a long period and proved to be efficient in plant gene transfer. The particle velocities were measured in a range of 43–82 m/s, which agreed well with the results of the theoretical approximation. The initial velocity of particles accelerated by the piezoelectric transmitter may be controlled by changing the driving voltage. The apparatus for accelerating particles using an elastic wave impulse features tightly static sealing of the sample chamber and minimization of the aerodynamic effect caused by particle acceleration.

In recent years, great strides have been made regarding the identification of the dominant loads that cause beam type vibrations of cannons during ballistic operation. These motions infringe upon shot accuracy because at projectile disengagement, the muzzle's kinematic state may compromise the projectile's intended flight path. This is particularly relevant to coil gun loading, which, unlike gas launch, applies the recoil load to the muzzle end of the barrel instead of the breech. This effectively places the barrel in a state of columnar compression during the launch cycle that may exacerbate structural vibrations known as gun "whip".

The method of design-ballistic optimization developed by authors assumes the solution of a task on a self-optimizing control. The Pontryagin's maximum principle is applied to transition to a boundary-value problem. Runge-Kutta-4 method is used for direct modeling of operated movement. Optimization of parameters is carried out by means of downhill simplex method. Solutions of a boundary-value problem on a self-optimizing control for flight of the minimum duration and the minimum expenses of a propellant are received with the fixed duration. Change of an expense of a gas working fluid on flight Earth Mars is analyzed at various parameters of the spacecraft.

Ignition transients are a critical and complex period of operation in solid rocket motors. During the ignition interval, many factors combine which must be taken into account in the design of the entire system. There are many methods in use to analyze different aspects of the ignition processes, and the level of analysis complexity varies with need and available resources. These methods vary from empirically based sizing rules to complex physics-based analyses. There are still many aspects of ignition transient behavior that have not been fully characterized, and research is continuing to fully understand all processes that occur during ignition transients in solid rocket motors. Keywords: ignition; solid rocket motor (SRM); propellant; ballistics; igniters; transient

With an appropriate test setup, the Hadland Photonics Ballistic Range Camera (SVR), designed primarily for exterior and terminal ballistics, can also be used very well for studying initiation events and analysing a variety of detonation phenomena. This paper discusses detonics experiments carried out with the Ballistic Range Camera explaining in detail the test setup and the analysis of the results. The ability of the camera system to superimpose up to 16 images on a single frame allowed particularly detailed examination of detonation propagation, velocity, corner turning distance and the non-reacting radial zones.

In order to meet the demand of measuring the impact location dispersion of flying objects, a measurement method basing on the four-light-screen combined array was put forward. The composition of the system was introduced, the measurement principle was analyzed, and the formula was deduced. When two or more flying objects going through the light-screen array at the same time, the identification algorithm of time sequence and projectile images was discussed according to that the principle of straight line projectile ballistic and the imaging principle of the array CCD. Finally the algorithm was verified on Matlab, the results show that the method presented is availability and it can measure the impact location dispersion parameters of the flying object.

Low efficiency of energy utilization is one of the most important bottlenecks for the electromagnetic railgun to go into application. While any improvement in emission efficiency presents amplifying effect in saving the overall energy, so it is very necessary to reduce aerodynamic losses generated during the projectile emission. In this paper, the view of interior ballistic aerodynamic losses in the emission of electromagnetic railgun is introduced. Through mathematical analysis and dynamic mesh CFD (computational fluid dynamics) simulations, explore the interior ballistic law and optimize aerodynamic shape of the projectile. The interior ballistic researches show that improving the electromagnetic force and the aerodynamic drag ratio can improve the emission efficiency of electromagnetic railgun, increasing the clearance between projectile and barrel can reduce the aerodynamic losses. For the aerodynamic shape, increasing the slenderness ratio, reducing the cone angle and so on can reduce aerodynamic losses. What's more, through the researches, we found that the aerodynamic optimizations are more valuable for large high-velocity projectile.