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The study aimed to investigate the influence of key technical determinants on shooting performance in both air rifle and pistol shooting disciplines. Following a systematic search across four databases (PubMed, CINAHL, SPORTDiscus, and Cochrane Library), a total of 22 articles were included. The findings indicate that there was a significant correlation between the stability of hold component, as measured by DEV_X (r = −0.60; 95% confidence interval (CI) = −0.69 to −0.49; p < 0.001) and HITf (r = 0.69; 95% CI = 0.56 to 0.79; p < 0.001) and shooting performance in both shooting disciplines. In addition, HITr, another stability component, revealed a significant positive correlation for shooting performance (r = 0.60; 95% CI = 0.35 to 0.77; p < 0.001) in air pistol shooting. Furthermore, in both disciplines, there was a significant positive correlation between shooting performance and measures of aiming accuracy such as COGhit (r = 0.64; 95% CI = 0.49 to 0.75; p < 0.001), Targetf (r = 0.75; 95% CI = 0.63 to 0.84; p < 0.001), and Targetr (r = 0.60; 95% CI = 0.33 to 0.78; p < 0.001). In both disciplines, there was a strong negative correlation between the cleanliness of triggering and shooting performance (r = −0.63; 95% CI = −0.75 to −0.48; p < 0.001). Time on target measure significantly correlated with shooting performance (r = 0.52; 95% CI = 0.31 to 0.68; p < 0.001) across both disciplines. The relationship between postural balance and shooting performance in air rifle shooting was negative, indicating that better postural balance is associated with improved shooting (r = −0.53; 95% CI = −0.69 to −0.33; p < 0.001). This review emphasizes the significance of various technical components in both air rifle and pistol disciplines. [ABSTRACT FROM AUTHOR]

We present the case of a patient who was shot through the heart with an air rifle and presented in a stable condition at our emergency department. At the time of presentation, the bullet was still present within the myocardium. Imaging, management, and outcome are discussed in this report. [ABSTRACT FROM AUTHOR]

The Philippines is a biodiversity hotspot with four endemic wild pig species. The Philippine Warty Pig is a medium to large size mammal that is usually solitary. They commonly exhibit crop raiding behavior, and hunting by farmers and poachers decreases populations of this species, which is listed as 'Vulnerable' in the IUCN Red List of Threatened Species. This study was conducted to determine the level of awareness of Philippine Warty Pig conservation practices among locals in sitio Datal Bad, West Lamidan, Don Marcelino Davao Occidental, Philippines. Responses (N = 50) were gathered by a survey questionnaire. Respondents were highly aware of Philippine Warty Pigs and policies toward wildlife conservation. They reported hunting pigs using air guns 'sorit', bow and arrow 'papana', harpoon 'bangkaw', and snare 'lit-ag'. The respondents added that they performed religious rituals and farming that may pose threats to Philippine Warty Pigs. They also manifested a willingness to work with government and academic institutions to enhance knowledge about conservation of pigs and other wildlife in their locality. [ABSTRACT FROM AUTHOR]

The purpose of this study was to quantify the bullet impact locations of the men's 10 m air pistol competition and propose objective metrics for evaluating shooting techniques. We automatically collected data from the top 20 competitors' shooting results using computer vision techniques. Metrics such as x-variance, y-variance, covariance, x-mean, y-mean, root mean square error (RMSE), x-mean score, and y-mean score were computed to investigate correlations among rankings, left–right and up–down shot groups, aiming relationships, and precision. Covariance analysis revealed significant interactions between horizontal and vertical aiming, highlighting the importance of balanced coordination between these directions for high performance. Athletes with lower covariance values, indicating less variation between horizontal and vertical aiming, tended to achieve higher rankings. Additionally, top-ranked athletes exhibited lower RMSE values, underscoring the importance of precision in achieving high scores. In conclusion, this study analyzed the correlation between x and y through covariance, examined its relationship with competition rankings, and proposed new indicators for training and performance enhancement. This study is novel in that it provides quantitative data to correct poor aiming and shooting habits by performing a covariance-based bidirectional correlation analysis, rather than simply analyzing bullet impact locations in a single horizontal or vertical direction. Our approach establishes a foundation for more data-driven and objective evaluations in the sport of shooting. [ABSTRACT FROM AUTHOR]

Since sound from Atlantic cod (Gadus morhua) plays a significant role during their spawning activities, it is imperative to gain insights into their sound pressure levels. This knowledge is particularly valuable for understanding how cod responds to anthropogenic sounds, such as the intense sound from seismic air guns. In field experiments within sea cages using multiple instruments, including underwater cameras, a hydrophone, and an underwater acoustic vector sensor (AVS), the source level of cod grunts was scientifically measured. The measurements yielded an estimated median source level of 123.1 dB re 1 µPa at 1 m (121.8–124.2 dB, 95% confidence interval). The compact AVS measured collocated acoustic pressure and acoustic particle motions in three dimensions, providing valuable information regarding acoustic directionality in addition to sound pressure. This directional information assists in detecting the grunt bearing, estimating probable grunt propagation ranges, and subsequently reducing uncertainties associated with the estimation of the grunt source level. These experiments have demonstrated the AVS measured the cod vocalisations with directional information and can be potentially broadly used in other marine bioacoustics monitoring and tracking research. [ABSTRACT FROM AUTHOR]

Objective We completed a prospective human cadaveric study to determine the ability of a ball bearing (BB) pellet to penetrate the orbit and/or surrounding structures. Methods A single trained sergeant officer discharged an alloy steel air rifle to eight cadaver orbits from four adult human cadaver heads. Five BB pellets each were aimed at three locations (caruncle, upper eyelid, or lower eyelid) at 10 cm and 1 m, and then less specifically, at the orbital region for 3- and 5-m distances. Computed tomography (CT) of the cadaver heads was performed. Final locations of BB pellets are divided into three categories: intracranial, surrounding orbital structures including the pterygopalatine fossa and infratemporal fossa, and orbit. Results Of 40 BB pellets, 37 penetrated soft tissue and were visualized on CT: 19 (51%) rested in the intracranial space, 17 (46%) in surrounding orbital structures, and 1 (3%) within the orbit. The deepest position of a pellet was in the parietal lobe, and most superficial location anterior to the frontal bone. Pellets discharged from 1 m were more likely to rest in the intracranial space compared with those from 10 cm (p < 0.001), 3 m (p = 0.011), and 5 m (p = 0.004). The distance of discharge was associated with final pellet location (p = 0.001). Conclusion BB guns should be considered dangerous and potentially deadly when aimed at the orbit. Although the thick calvarium can protect the intracranial space from BB penetration, the orbit may be a vulnerable entry point with relatively low resistance, allowing penetration of the intracranial and periorbital spaces. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the physiological parameters and quiet eye (QE) of air pistol shooters in relation to performance outcomes. QE duration, skin conductance (SC), and heart rate (HR) were recorded for 20 shooters (10 novices and 10 intermediates) during shooting. All variables were examined according to the score and total shots. Physiological parameters were evaluated according to the shooting phases. Intermediate shooters exhibited significantly longer QE duration than novices (p <.001). There were no significant differences in QE duration and normalised SC according to the score and normalised SC between groups (p >.05). In SC, an increase in the preparation and resting phase and a decrease in the aiming phase were observed in both groups (p <.001). Intermediate shooters had lower HR than novices in all phases (p <.001). Additionally, more HR changes were detected in the intermediate shooters than in novices. HR of 10-score shots was lower than other shots (p <.05). Intermediate shooters exhibited longer QE duration than novices and they can decelerate their HR before shots. Coaches are recommended to incorporate exercises into training programmes that will enhance the visual focusing skills and reduce heart rate for novice shooters. [ABSTRACT FROM AUTHOR]

Reconfigurable intelligent surfaces (RISs) have the potential to improve wireless communication links by dynamically redirecting signals to dead spots. Although a reconfigurable surface is best suited for environments in which the reflected signal must be dynamically steered, there are cases where a static, non-reconfigurable anomalous reflective metasurface can suffice. In this work, spray-coated liquid metal is used to rapidly prototype an anomalous reflective metasurface. Using a pressurized air gun and a plastic thin-film mask, a metasurface consisting of a 6 × 4 array of Galinstan liquid–metal elements is sprayed within minutes. The metasurface produces a reflected wave at an angle of 28° from normal in response to a normal incident 3.5-GHz electromagnetic plane wave. The spray-coated liquid–metal metasurface shows comparable results to an anomalous reflective metasurface with copper elements of the same dimensions, demonstrating that this liquid–metal fabrication process is a viable solution for the rapid prototyping of anomalous reflective metasurfaces. [ABSTRACT FROM AUTHOR]

Biologists and veterinarians rely on dart projectors to inject animals with drugs, take biopsies from specimens, or inject tracking chips. Firearms, air guns, and other launchers are limited in their ability to precisely control the kinetic energy of a projectile, which can injure the animal if too high. In order to improve the safety of remote drug delivery, a lidar-modulated electromagnetic launcher and a soft drug delivery dart were prototyped. A single-stage revolver coilgun and soft dart were designed and tested at distances up to 8 m. With a coil efficiency of 2.25%, the launcher could consistently deliver a projectile at a controlled kinetic energy of 1.00 ± 0.006 J and an uncontrolled kinetic energy of 2.66 ± 0.076 J. Although modifications to charging time, sensors, and electronics could improve performance, our launcher performed at the required level at the necessary distances. The precision achieved with commercial components enables many other applications, from law enforcement to manufacturing. [ABSTRACT FROM AUTHOR]

Physiologic hand tremors are a critical factor affecting the aim of air pistol shooters. However, the extent of the effect of hand tremors on shooting performance is unclear. In this study, we aim to explore the relationship between hand tremors and shooting performance scores as well as investigate potential links between muscle activation and hand tremors. In this study, 17 male air pistol shooters from China's national team and the Air Pistol Sports Center were divided into two groups: the elite group and the sub-elite group. Each participant completed 40 shots during the experiment, with shooters' hand tremors recorded using three-axis digital accelerometers affixed to their right hands. Muscle activation was recorded using surface electromyography on the right anterior deltoid, posterior deltoid, biceps brachii (short head), triceps brachii (long head), flexor carpi radialis, and extensor carpi radialis. Our analysis revealed weak correlations between shooting scores and hand tremor amplitude in multiple directions (middle-lateral, ML: r2 = −0.22, p < 0.001; vertical, VT: r2 = −0.25, p < 0.001), as well as between shooting scores and hand tremor complexity (ML: r2 = −0.26, p < 0.001; VT: r2 = −0.28, p < 0.001), across all participants. Notably, weak correlations between shooting scores and hand tremor amplitude (ML: r2 = −0.27, p < 0.001; VT: r2 = −0.33, p < 0.001) and complexity (ML: r2 = −0.31, p < 0.001) were observed in the elite group but not in the sub-elite group. Moderate correlation were found between the biceps brachii (short head) RMS and hand tremor amplitude in the VT and ML directions (ML: r2 = 0.49, p = 0.010; VT: r2 = 0.44, p = 0.025) in all shooters, with a moderate correlation in the ML direction in elite shooters (ML: r2 = 0.49, p = 0.034). Our results suggest that hand tremors in air pistol shooters are associated with the skill of the shooters, and muscle activation of the biceps brachii (long head) might be a factor affecting hand tremors. By balancing the agonist and antagonist muscles of the shoulder joint, shooters might potentially reduce hand tremors and improve their shooting scores. [ABSTRACT FROM AUTHOR]

Pressure waves emitted from the air gun contain many frequencies, among which low-frequency waves are desirable for exploration and imaging, while high-frequency waves need to be suppressed as they are harmful to marine species. The high-frequency waves originate from the fast oscillations of the flow during the release of the air, such as the impingement of the gas jet into the liquid, the expansion of the air gun bubble, and the interaction between the air gun body and the bubble. However, those dynamic and the emitted waves are adjustable by the special design of the air guns. To analyze the underlying relations, we present a numerical study with a compressible air gun bubble model using the volume of fluid (VOF) approach combined with the finite volume method (FVM) implemented in STAR-CCM+. The venting process of an air gun is investigated to reveal the influence of the air gun body. The results show that air gun pressure for the far field is mainly proportional to the expansion acceleration of the whole gas. Our results also indicate that the opening and chamber shape of the air gun affects the gas expansion acceleration, which influences the first peak of the pressure wave significantly. The larger the opening is, the faster the gas is released, the greater the amplitude of the first peak is. The larger the chamber length/diameter ratio, the slower the gas is released and the lower the amplitude of the first peak. [ABSTRACT FROM AUTHOR]

How to effectively reduce the high-frequency output caused by excessively steep initial peak slope and enhance the low-frequency output generated by bubble oscillation has become present research interest in seismic source design. The most effective way to improve the low-frequency content of a seismic source is to increase its chamber volume. However, the size of air-gun bubbles generated by large-volume air-gun sources has increased by several hundred times compared to traditional high-pressure air guns, which has made the migration phenomenon of bubbles no longer negligible. The previous air-gun bubble dynamics models did not comprehensively account for the effects caused by bubble migration phenomenon. In this paper, we have developed an air-gun bubble dynamics model based on unified equation for bubble dynamics, and the newly established model demonstrates a closer alignment with experimental data compared to models based on the Gilmore and Keller equations. Based on this, the influence of the design parameters of air-gun seismic source on the bubble migration is studied. It explores the ramifications of migration on the dynamic properties of air-gun bubbles and the signatures of seismic sources. Additionally, we examine how incoming flow velocity magnitude and air-gun design parameters influence the signatures of air-gun seismic sources. Finally, we investigate the impact of both the spacing between dual guns and the horizontal movement of bubbles caused by mutual attraction on the signatures of dual-gun sources. [ABSTRACT FROM AUTHOR]

The high-speed ice-ball impact damage research of epoxy resin/carbon fiber 3D four-way braided composites was carried out. Using the air gun impact test system, ice balls with three different impact velocities were used to conduct impact tests. After the test, industrial CT scans were performed on the main damage positions of the test pieces, and the internal damage forms were observed. The composite macro constitutive model based on surface unit-cell and interior unit-cell and a strain rate related material model of the ice were used to establish the finite element model. The simulation model was compared with the test. The results show that the damage of the matrix in the surface unit-cell area is more serious than that in the interior unit-cell area, the damage area of the front surface is generally larger than that of the back surface, the oblique impact angle has an influence on the damage area and damage location. As the impact angle decreases, the damage area of the composite material also decreases. Increasing the thickness of plate can improve the ability to absorb energy and reduce the damage area of the material. [ABSTRACT FROM AUTHOR]

Copyright of SPORMETRE: The Journal of Physical Education & Sport Sciences / Beden Eğitimi ve Spor Bilimleri Dergisi is the property of SPORMETRE: The Journal of Physical Education & Sport Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Air rifle injuries can cause significant vascular injuries. This air rifle injury has resulted in a penetrating neck trauma traversing the common carotid artery. There is debate around the need for radiological investigation, the most appropriate investigational modality, and the need for surgical exploration versus a conservative approach. This case report aims to exemplify a successful approach to managing Penetrating Carotid Injuries (PCI) while shedding light on the rationale behind the management decisions. Presentation: An 18-year-old Caucasian man arrived at the hospital following an air rifle injury to the right side of the neck, with active bleeding and a moderate haematoma displacing the trachea. He was haemodynamically stable, with a Glasgow Coma Scale (GCS) of 15 and no evidence of bruit. Computed Tomography Angiography (CTA) showed Right common carotid (CCA) artery injury with associated post-traumatic pseudoaneurysm. The pellet trajectory traverses the right superior thyroid gland. A duplex ultrasound scan (USS) confirmed two areas of arterial blush at the right CCA. Management involved neck exploration under General Anaesthesia (G.A.), repair of right CCA, bullet extraction, and wound washout. He received antibiotics for ten days and a single agent of antiplatelets for three months and was discharged two days postoperatively with no complications. He was followed up for eight months with no evidence of any trauma sequelae. Conclusion: Penetrating carotid artery injuries are a serious concern. The small-sized pellets carry the risk of embolization. Therefore, neck exploration remains the gold standard treatment for PCI. Appropriate operative planning is crucial and can be optimised using radiological diagnostic modalities in haemodynamically stable patients. CTA is a non-invasive, swift, and adequate alternative to arteriography, providing valuable diagnostic information on vascular and aerodigestive injuries and bullet trajectory. This enables appropriate preparedness to achieve excellent outcomes in such critical cases. [ABSTRACT FROM AUTHOR]

In the latest geophysical survey crossing the Ninety East Ridge of the Indian Ocean, a new method was employed to perform proportional double seismic source excitation and synchronously receive signals from the sea surface and the seabed. The two seismic sources used for excitation were two sets of gun arrays with different energies and dominant frequencies, a G gun array and a Bolt gun array. The G gun array consisted of 3 G.II guns with a total capacity of 450 in3 and a dominant frequency of 20–100 Hz. The Bolt gun array consisted of 4 Bolt 1500LL air guns with a total capacity of 6000 in3 and a dominant frequency of 10–40 Hz. The seismic receiving system comprised a 480-channel seismic streamer towed from the sea surface and 21 ocean bottom seismometers (OBS). During offshore operations, the integrated navigation system produced equidistant trigger signals at an interval of 50 m. The trigger signals were distributed to the G gun array and Bolt gun array at a ratio of 3:1 after passing through a pulse signal proportional distributor. The two sets of gun arrays fired alternatingly at a given ratio. The receiving equipment on the sea surface and seabed simultaneously received the seismic signals excited by the two sets of gun arrays. After targeted data processing, in addition to the seismic profile generated by the conventional G gun seismic source, the deep seismic profile generated by the Bolt gun seismic source and the survey profile of the active-source OBS were obtained simultaneously. The penetration depths of the three sets of profiles reach 2 km, 6 km, and 30 km, respectively, greatly improving the efficiency of offshore deep-sea seismic surveys. [ABSTRACT FROM AUTHOR]

The auditory steady-state response (ASSR) was continuously measured in two bottlenose dolphins during impulse noise exposures to determine whether observed head movements coincided with actual changes to auditory system sensitivity. Impulses were generated by a seismic air gun at a fixed inter-pulse interval of 10 s. ASSR amplitudes were extracted from the instantaneous electroencephalogram using coherent averaging within a sliding analysis window. A decline in ASSR amplitude was seen during the time interval between air gun impulses, followed by an elevation in ASSR amplitude immediately after each impulse. Similar patterns were not observed during control trials where air gun impulses were not generated. The results suggest that the dolphins learned the timing of the impulse noise sequences and lowered their hearing sensitivity before each impulse, presumably to lessen the auditory effects of the noise. The specific mechanisms responsible for the observed effects are at present unknown. [ABSTRACT FROM AUTHOR]

The validity of a commonly used optoelectronic training system was examined by identifying the variables that predicted shot score, investigating their ability to discriminate standard, and assessing the predictive variables' test–retest error. A repeated-measures approach assessed test–retest error, a cross-sectional approach compared standards of shooters and an observational approach examined predictors of shot score. 21 elite and 8 national-standard athletes participated. Multiple linear regression, independent t tests, typical error and coefficient of variation assessed predictors of shot score, discrimination between standards and test–retest error respectively. Stability of aiming predicted 84.2% of the variance in shot score. Six Scatt Expert variables, 10a0, 10a5, 10.0, 10.5, Speed in the last 250 mm, and stability of aiming, discriminated standard (P < 0.05). Test–retest error ranged from a coefficient of variance of 0.72% for 10a0 to 30.69% for Accuracy of Aiming. Stability of aiming had a typical error of 0.55 mm and a coefficient of variance of 13.93%. Results suggest that this optoelectronic training system possesses construct validity if stability of aiming is used as the outcome measure. [ABSTRACT FROM AUTHOR]

Marine passive acoustic monitoring can be used to study biological, geophysical, and anthropogenic phenomena in the ocean. The wide range of characteristics from geophysical, biological, and anthropogenic sounds sources makes the simultaneous automatic detection and classification of these sounds a significant challenge. Here, we propose a single Hidden Markov Model-based system with a Deep Neural Network (HMM-DNN) for the detection and classification of low-frequency biological (baleen whales), geophysical (earthquakes), and anthropogenic (air guns) sounds. Acoustic data were obtained from the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization station off Juan Fernandez, Chile (station HA03) and annotated by an analyst (498 h of audio data containing 30,873 events from 19 different classes), and then divided into training (60%), testing (20%), and tuning (20%) subsets. Each audio frame was represented as an observation vector obtained through a filterbank-based spectral feature extraction procedure. The HMM-DNN training procedure was carried out discriminatively by setting HMM states as targets. A model with Gaussian Mixtures Models and HMM (HMM-GMM) was trained to obtain an initial set of HMM target states. Feature transformation based on Linear Discriminant Analysis and Maximum Likelihood Linear Transform was also incorporated. The HMM-DNN system displayed good capacity for correctly detecting and classifying events, with high event-level accuracy (84.46%), high weighted average sensitivity (84.46%), and high weighted average precision (89.54%). Event-level accuracy increased with higher event signal-to-noise ratios. Event-level metrics per class also showed that our HMM-DNN system generalized well for most classes but performances were best for classes that either had a high number of training exemplars (e.g., generally above 50) and/or were for classes of signals that had low variability in spectral features, duration, and energy levels. Fin whale and Antarctic blue whale song and air guns performed particularly well. [ABSTRACT FROM AUTHOR]

Air gun arrays are designed to generate strong energy pulses of less than 100 Hz for offshore oil and gas exploration. In shallow seas, due to the directivity of air gun arrays, the complex propagation conditions and the limitations of acquisition methods, it is difficult to accurately evaluate the spatial time and frequency transmission characteristics of airguns. To alleviate the existing lack of knowledge about the transmission characteristics of air gun pulses in the shallow waters of the Bohai Sea, we analysed three‐dimensional ocean bottom cable seismic data collected during a seismic survey in the Bohai Sea, China, in June 2017, which were used to evaluate the reception level, frequency domain characteristics and spatial distribution characteristics within a 5.55 × 5.575 km area. The results showed that in shallow water, multipath propagation causes downfrequency chirplike sounds and an increased sound field. Within 0.3 km, the transmission model follows a cylindrical diffusion, and the sound loss rate decreases as the transmission distance increases until reaching 8 km. Signal capture by the sound channel results in a high transmission loss frequency band, whereas multimode interference weakens the transmission loss. The gun array directivity and the transmission channel are the two main factors affecting the acoustic field. This research provides an improved understanding of the acoustic field of airguns in the Bohai Sea, which can benefit the acoustic modelling of air gun arrays, the design of future seismic exploration projects and the conservation of marine life. [ABSTRACT FROM AUTHOR]

Copyright of Turkish Journal of Sport & Exercise / Türk Spor ve Egzersiz Dergisi is the property of Turkish Journal of Sport & Exercise and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electroplating & Finishing is the property of Electroplating & Finishing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction: Air guns are widely used for recreation and to protect crops from animals. It is a pneumatic weapon capable of inflicting serious life-threatening injuries. The authors present a case of a child subjected to a life-threatening pellet injury to the head due to discharge of an air gun while playing. Case report: A 3 ½ year old male child who was 95 cm in height presented with a circular perforated laceration 0.4 cm in diameter with surrounding abrasion collar on the right side of the face over the zygomatic arch, nasal bleeding and aspiration of blood. Imaging studies revealed a diabolo-shaped foreign body resembling a pellet of an air gun in the left pharyngeal space. The foreign body was removed under image guidance. Investigation revealed that the parents used an air gun on the farm to protect their crops from monkeys. Since examination of the weapon and child indicated that he could not have caused the injury himself, we concluded that another child had fired the weapon accidentally, during play. Conclusions: The findings were compatible with those caused by discharge of an air gun. This case re-emphasizes the importance of keeping this type of weapons away from children. We recommend that air guns be governed by the same laws that apply to firearms.

Copyright of Ordnance Industry Automation is the property of Editorial Board for Ordnance Industry Automation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We conducted seismic tomography for entire Japanese Islands including the Sea of Japan and the Pacific Ocean using arrival times from reflection survey as well as the routine seismic network. We successfully imaged the shallow zone along the Sea of Japan from offshore Yamagata to the Noto Peninsula by using air gun data. An extremely low-V shallow zone is imaged between Sado Island and Noto Peninsula. We also obtained detailed seismic velocity structure beneath the Pacific Ocean at depths of 20–50 km using S-net data. The 2007 Noto Peninsula, the 2007 offshore Chuetsu, and the 2019 offshore Yamagata earthquakes occurred at the boundary between high-Vp and low-Vp zones. The west side of the hypocenter of the 2019 offshore Yamagata earthquake at depths of 10–30 km has high-V corresponding to the Mogami Trough. This high-V zone passes through Awa Island and reaches Sado Basin between Sado Island and Honshu. A major rift zone in the Tohoku Arc extending from the Akita region to the Niigata region along the coast of Sea of Japan corresponds to high-V lower crust and a shallow Moho. [ABSTRACT FROM AUTHOR]

Ballistic resistance is affected by the projectile and armor material used. The character and behavior of the projectile affects its ability to damage and penetrate armor. The velocity, mass and shape of the projectile are the main factors in determining the ability of the projectile to penetrate armor in this case the target plate. Therefore, this study aims to determine and analyze the effect of projectile mass and shape on the velocity with which it penetrates the armor material using a compressed air gun. Armor material as a ballistic test target using carbon steel plate with a thickness of 0.8 mm; 1.2 mm and 1.8 mm. Projectiles of lead materials with different masses and shapes are fired from the air gun under controlled air pressure, set at 2000 Psi, 3000 Psi, and 4000 Psi to provide thrust in the barrel. The plat target is placed at a distance of 5 m from the air gun. Speed gauges are placed after the air gun and after the target plate to determine the projectile's rate before and after passing through the target plate. The test results concluded that the velocity of the projectile ejected from the compressed air gun was influenced by the magnitude of the pressure and the mass of the projectile. The mass of the projectile has a more dominant effect on the velocity of the projectile compared to the amount of pressure applied. Different projectile shapes with the same mass have no significant effect on the velocity. However, the heavier mass projectile outperforms the lighter mass projectile through the target plate. It is required the right combination of velocity and mass of the projectile to be able to penetrate the target plate. [ABSTRACT FROM AUTHOR]

Various types of coatings are applied to the surface of an object or substrate to improve surface properties or extend service life, which in turn is associated with cost reductions. The main objective of this study was to develop a technique for the additive application of foamed geopolymers to existing structures and vertical surfaces. The base material was a fly ash-based geopolymer modified with sand. Hydrogen peroxide and aluminum powder were used as foaming agents. In this study, the feasibility of using an air gun with variable nozzles to apply the layers of foamed geopolymers was assessed, and the effects of nozzle diameter and the spray gun's operating pressure were analyzed. The next stage of the study was a visual assessment of the layering of the foamed material. The foamed geopolymer layering tests verified the occurrence of the foaming process, and the applied geopolymer surface showed a reasonably good adhesive bond with the vertical wall. In addition, in this paper, we present the laser particle size results of the base materials and their oxide composition. In addition, thermal conductivity tests for the foamed geopolymer materials, compressive strength tests, and microstructure analysis via scanning electron microscopy were carried out. [ABSTRACT FROM AUTHOR]

The record of seismic, hydroacoustic, and infrasonic waves is essential to detect, identify, and localize sources of both natural and anthropogenic origin. To guarantee traceability and inter-station comparability, as well as an estimation of the measurement uncertainties leading to a better monitoring of natural disasters and environmental aspects, suitable measurement standards and reliable calibration procedures of sensors, especially in the low-frequency range down to 0.01 Hz, are required. Most of all with regard to the design goal of the Comprehensive Nuclear-Test-Ban Treaty Organisation's International Monitoring System, which requires the stations to be operational nearly 100% of the time, the on-site calibration during operation is of special importance. The purpose of this paper is to identify suitable excitation sources and elaborate necessary requirements for on-site calibrations. We give an extensive literature review of a large variety of anthropogenic and natural sources of seismic, hydroacoustic, and infrasonic waves, describe their most prominent features regarding signal and spectral characteristics, explicitly highlight some source examples, and evaluate the reviewed sources with respect to requirements for on-site calibrations such as frequency bandwidth, signal properties as well as the applicability in terms of cost–benefit. According to our assessment, earthquakes stand out across all three waveform technologies as a good natural excitation signal meeting the majority of the requirements. Furthermore, microseisms and microbaroms allow a calibration at very low frequencies. We also find that in each waveform technique man-made controlled sources such as drop weights or air guns are in good agreement with the required properties, although limitations may arise regarding the practicability. Using these sources, procedures will be established allowing calibration without record interrupting, thereby improving data quality and the identification of treaty-related events. Article Highlights: Various sources of seismic, hydroacoustic, and infrasonic waves are analysed regarding their waveform and frequency content We evaluate the potential use of both natural and anthropogenic sources as excitation signals for on-site calibration Earthquakes and man-made signals are in best agreement with the required properties for excitation signals [ABSTRACT FROM AUTHOR]

During the summer of 2015, four 4D seismic surveys were conducted on the northeastern Sakhalin shelf near the feeding grounds of the Korean-Okhotsk (western) gray whale (Eschrichtius robustus) population. In addition to the seismic surveys, onshore pile driving activities and vessel operations occurred. Forty autonomous underwater acoustic recorders provided data in the 2 Hz to15 kHz frequency band. Recordings were analyzed to evaluate the characteristics of impulses propagating from the seismic sources. Acoustic metrics analyzed comprised peak sound pressure level (PK), mean square sound pressure level (SPL), sound exposure level (SEL), T100%, T90% (the time intervals that contain the full and 90% of the energy of the impulse), and kurtosis. The impulses analyzed differed significantly due to the variability and complexity of propagation in the shallow water of the northeast Sakhalin shelf. At larger ranges, a seismic precursor propagated in the seabed ahead of the acoustic impulse, and the impulses often interfered with each other, complicating analyses. Additional processing of recordings allowed evaluation and documentation of relevant metrics for pile driving, vessel sounds, and ambient background levels. The computed metrics were used to calibrate acoustic models, generating time resolved estimates of the acoustic levels from seismic surveys, pile driving, and vessel operations on a gray whale distribution grid and along observed gray whale tracks. This paper describes the development of the metrics and the calibrated acoustic models, both of which will be used in work quantifying gray whale behavioral and distribution responses to underwater sounds and to determine whether these observed responses have the potential to impact important parameters at the population level (e.g., reproductive success). [ABSTRACT FROM AUTHOR]

In 2015, two oil and gas companies conducted seismic surveys along the northeast coast of Sakhalin Island, Russia, near western gray whale (Eschrichtius robustus) feeding areas. This population of whales was listed as Critically Endangered at the time of the operations described here but has been reclassified as Endangered since 2018. The number and duration of the 2015 seismic surveys surpassed the level of previous seismic survey activity in this area, elevating concerns regarding disturbance of feeding gray whales and the potential for auditory injury. Exxon Neftegas Limited (ENL) developed a mitigation approach to address these concerns and, more importantly, implemented a comprehensive data collection strategy to assess the effectiveness of this approach. The mitigation approach prioritized completion of the seismic surveys closest to the nearshore feeding area as early in the season as possible, when fewer gray whales would be present. This was accomplished by increasing operational efficiency through the use of multiple seismic vessels and by establishing zones with specific seasonal criteria determining when air gun shutdowns would be implemented. These zones and seasonal criteria were based on pre-season modeled acoustic footprints of the air gun array and on gray whale distribution data collected over the previous 10 years. Real-time acoustic and whale sighting data were instrumental in the implementation of air gun shutdowns. The mitigation effectiveness of these shutdowns was assessed through analyzing short-term behavioral responses and shifts in gray whale distribution due to sound exposure. The overall mitigation strategy of an early survey completion was assessed through bioenergetics models that predict how reduced foraging activity might affect gray whale reproduction and maternal survival. This assessment relied on a total of 17 shore-based and 5 vessel-based teams collecting behavior, distribution, photo-identification, prey, and acoustic data. This paper describes the mitigation approach, the implementation of mitigation measures using real-time acoustic and gray whale location data, and the strategy to assess impacts and mitigation effectiveness. [ABSTRACT FROM AUTHOR]

Gunshot injuries are a rare cause of vascular injury in the pediatric age group, mostly occurring accidentally. They are very serious injuries and could even be life- or limb-threatening, even with slow-velocity bullets. Here, we report two cases of vascular injury induced by different types of weapons. The first case was a four-year-old boy who presented with a left axillary artery injury caused by a gunshot bullet. The diagnosis was made by a computerized tomography angiogram (CTA). CTA showed a pseudo-aneurysm and complete disruption of the left axillary artery at the upper limb. The injury was treated immediately with exploration of the axillary artery, debridement of the injured area of the artery, and repair with an interposition saphenous graft. Postoperatively, the patient did well with good healing of the wound and regained normal upper limb pulses. The second case was a 10-year-old boy who was shot with an air rifle from a very short distance. This caused the bullet to directly penetrate the left side of his neck and injure the anterior surface of the left common carotid artery (CCA). Initially, the CTA missed the diagnosis, but the injury was diagnosed by duplex ultrasound on the third day of admission, which showed a pseudo-aneurysm at the anterior surface of the left CCA. The patient did not manifest any neurological signs or symptoms. He underwent surgical exploration of the CCA, and primary repair of the small hole located at the anterior wall. The patient recovered well with no neurological events. [ABSTRACT FROM AUTHOR]

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Marine passive acoustic monitoring can be used to study biological, geophysical, and anthropogenic phenomena in the ocean. The wide range of characteristics from geophysical, biological, and anthropogenic sounds sources makes the simultaneous automatic detection and classification of these sounds a significant challenge. Here, we propose a single Hidden Markov Model-based system with a Deep Neural Network (HMM-DNN) for the detection and classification of low-frequency biological (baleen whales), geophysical (earthquakes), and anthropogenic (air guns) sounds. Acoustic data were obtained from the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization station off Juan Fernandez, Chile (station HA03) and annotated by an analyst (498 h of audio data containing 30,873 events from 19 different classes), and then divided into training (60%), testing (20%), and tuning (20%) subsets. Each audio frame was represented as an observation vector obtained through a filterbank-based spectral feature extraction procedure. The HMM-DNN training procedure was carried out discriminatively by setting HMM states as targets. A model with Gaussian Mixtures Models and HMM (HMM-GMM) was trained to obtain an initial set of HMM target states. Feature transformation based on Linear Discriminant Analysis and Maximum Likelihood Linear Transform was also incorporated. The HMM-DNN system displayed good capacity for correctly detecting and classifying events, with high event-level accuracy (84.46%), high weighted average sensitivity (84.46%), and high weighted average precision (89.54%). Event-level accuracy increased with higher event signal-to-noise ratios. Event-level metrics per class also showed that our HMM-DNN system generalized well for most classes but performances were best for classes that either had a high number of training exemplars (e.g., generally above 50) and/or were for classes of signals that had low variability in spectral features, duration, and energy levels. Fin whale and Antarctic blue whale song and air guns performed particularly well.

Orbital apex fractures are a debilitating condition that can cause vision problems and are often associated with intracranial injury. Traumatic Optic Neuropathy (TON), which results in vision loss following a traumatic injury to the optic nerve, can be caused by various mechanisms, but most cases involve injuries to the globe, orbit, or adnexa. We are reporting a case of an 18 year old male with a history of an air gun being accidentally discharged into his left eye. He was evaluated and found to have an Orbital apex fracture with left eye TON. Patient was administered high dose steroids. Detailed evaluation by Ophthalmology revealed a left eye traumatic stage I macular hole which was conservatively treated with visual improvement reported during patient follow up. [ABSTRACT FROM AUTHOR]

Treating Kevlar fabric with silica nanoparticles is known to augment its mechanical properties, especially under shear deformation. Silica nanoparticle-treated Kevlar (SNK) fabric could therefore display improved ballistic performance. In this study, the ballistic performance of SNK with various percentages by weight of nanoparticle addition and number of layers is evaluated using compressed air gun experiments. A colloid-based treatment procedure is used to impregnate dry silica nanoparticles into the fabric. Addition of nanoparticles provided about 17.3% mass advantage (due to three fewer layers) for the 40 wt.% SNK vis-à-vis neat Kevlar for the non-penetrative case. SEM imaging reveals that at higher treatment levels the nanoparticles tend to agglomerate in the interstitial spaces of yarn crossover points, which helps better engage secondary yarns away from the impact location of the projectile. A semi-empirical model is developed to capture the influence of treatment level and number of layers on the kinetic energy absorbed by SNK. The flexibility of SNK is tested using a fixed cantilever test that avoids the sliding of the sample between flat plates used in standardized tests, which tends to dislodge the nanoparticles. The measured tip deflection angle decreases from 33o for the neat fabric to 19o for the 40 wt.% SNK. The flexural rigidities educed using digital image analysis range from 48.9 μNm2 for the neat fabric to 113.7 μNm2 for the 40 wt.% case. SNK could potentially enable multifunctional structural solutions in applications related to personal protective gear, military vehicle hulls and impact shielding of space structures. [ABSTRACT FROM AUTHOR]

Intense sound sources, such as pile driving, airguns, and military sonars, have the potential to inflict hearing loss in marine mammals and are, therefore, regulated in many countries. The most recent criteria for noise induced hearing loss are based on empirical data collected until 2015 and recommend frequency-weighted and species group-specific thresholds to predict the onset of temporary threshold shift (TTS). Here, evidence made available after 2015 in light of the current criteria for two functional hearing groups is reviewed. For impulsive sounds (from pile driving and air guns), there is strong support for the current threshold for very high frequency cetaceans, including harbor porpoises (Phocoena phocoena). Less strong support also exists for the threshold for phocid seals in water, including harbor seals (Phoca vitulina). For non-impulsive sounds, there is good correspondence between exposure functions and empirical thresholds below 10 kHz for porpoises (applicable to assessment and regulation of military sonars) and between 3 and 16 kHz for seals. Above 10 kHz for porpoises and outside of the range 3–16 kHz for seals, there are substantial differences (up to 35 dB) between the predicted thresholds for TTS and empirical results. These discrepancies call for further studies. [ABSTRACT FROM AUTHOR]

Transcranial direct current stimulation (tDCS) has been shown to improve motor learning in numerous studies. However, only a few of these studies have been conducted on elite-level performers or in complex motor tasks that have been practiced extensively. The purpose was to determine the influence of tDCS applied to the dorsolateral prefrontal cortex (DLPFC) on motor learning over multiple days on 10-m air rifle shooting performance in elite Deaflympic athletes. Two male and two female elite Deaflympic athletes (World, European, and National medalists) participated in this case series. The study utilized a randomized, double-blind, SHAM-controlled, cross-over design. Anodal tDCS or SHAM stimulation was applied to the left DLPFC for 25 min with a current strength of 2 mA concurrent with three days of standard shooting practice sessions. Shooting performance was quantified as the points and the endpoint error. Separate 2 Condition (DLPFC-tDCS, SHAM) × 3 Day (1,2,3) within-subjects ANOVAs revealed no significant main effects or interactions for either points or endpoint error. These results indicate that DLPFC-tDCS applied over multiple days does not improve shooting performance in elite athletes. Different stimulation parameters or very long-term (weeks/months) application of tDCS may be needed to improve motor learning in elite athletes. [ABSTRACT FROM AUTHOR]