Dynamic pressure measurement of cartridge operated vole captive bolt devices

IntroductionVole captive bolt devices are powder actuated spring guns that are used as a pest control mean. After having triggered the explosion of the blank cartridge by touching a metal ring around the muzzle, the vole is killed by the massive propulsion of the gas jet. Improper use and recklessness while handling these devices may cause severe injuries with the hand of the operator at particular risk. Currently, there are no experimental investigations on the ballistic background of these devices.MethodsAn experimental test set-up was designed for measurement of the firing pressure and the dynamic force of the gas jet of a vole captive bolt device. Therefore, a vole captive bolt device was prepared with a pressure take-off channel and a piezoelectric transducer for measurement of the firing pressure. For measurement of the dynamic impact force of the gas jet an annular quartz force sensor was installed on a test bench. Each three simultaneous measurements of the cartridges’ firing pressure and the dynamic force of the blast wave were taken at various distances between muzzle and load washer.ResultsThe maximum gas pressure in the explosion chamber was up to 1100 bar. The shot development over time showed a typical gas pressure curve. Flow velocity of the gas jet was up to 2000 m/s. The maximum impact force of the gas jet at the target showed a strong inverse ratio to the muzzle's distance and was up to 11,500 N for the contact shot distance. Energy density of the gas jet for the close contact shot was far beyond the energy density required for skin penetration.ConclusionThe unique design features (short tube between cartridge mouth and muzzle and narrow diameter of the muzzle) of these gadgets are responsible for the high firing pressure, velocity and force of the gas jet. These findings explain the trauma mechanics of the extensive tissue damage observed in accidental shots of these devices.     

Influence of Muzzle Instability on Bullet Deflection after Perforating Laminated Particleboards

The influence of muzzle instability on bullet deflection, when perforating laminated particleboards, was studied with three different handgun bullet types. The mean deflection angles of .32 Auto FMJ and .38 Special SJHP bullets were calculated to be 0.90° and 0.83°, respectively after perforating particleboards orthogonally at a 1 m muzzle-to-target distance. The mean angles dropped to 0.70° and 0.58° at a 15 m muzzle-to-target distance. The differences in deflection angles proved to be statistically significant (p < 0.05) with p-values of 0.023 and 0.001, respectively. The mean calculated deflection angles of .38 Special LRN bullets also dropped from 1.51° to 1.38° when the muzzle-to-target distance was increased from 1 to 15 m, but this difference was not significant (p-value of 0.357). The results support the hypothesis that muzzle instability has an influence on deflection. The possible implications for shooting incident reconstructions and for future research are discussed.     

Accuracy and Repeatability of Trajectory Rod Measurement Using Laser Scanners

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

Scanning Electron Microscope Analysis of Gunshot Defects to Bone: An Underutilized Source of Information on Ballistic Trauma

Recent years have seen increasing involvement by forensic anthropologists in the interpretation of skeletal trauma. With regard to ballistic injuries, there is now a large literature detailing gross features of such trauma; however, less attention has been given to microscopic characteristics. This article presents analysis of experimentally induced gunshot trauma in animal bone (Bos taurus scapulae) using full metal jacket (FMJ), soft point (SP), and captive bolt projectiles. The results were examined using scanning electron microscopy (SEM). Additional analysis was conducted on a purported parietal gunshot lesion in a human cranial specimen. A range of features was observed in these samples suggesting that fibrolamellar bone response to projectile impact is analogous to that observed in synthetic composite laminates. The results indicate that direction of bullet travel can be discerned microscopically even when it is ambiguous on gross examination. It was also possible to distinguish SP from FMJ lesions. SEM analysis is therefore recommended as a previously underexploited tool in the analysis of ballistic trauma.     

Planned Complex Occupation‐related Suicide by Captive‐bolt Gunshot and Hanging*

Abstract: Planned complex suicides are committed by using two or more previously planned methods simultaneously to make sure that death will occur even if one method fails. Herein, we presented a case of occupation‐related planned complex suicide, committed by captive‐bolt gunshot and hanging. A 29‐year‐old man, who worked as a butcher, was found dead in the stable, hanging by the neck with a captive‐bolt gun embedded in the forehead region of his head. The hanging was complete. Along the bolt canal were bone fragments, and at the end of the path was the punched‐out fragment of the skin and soft tissue. There were no fractures of the hyoid bone and laryngeal cartilages, and a superficial hemorrhage was present in the right sternocleidomastoid muscle. Our case underlines the utility of forensic autopsy and death scene investigation in reconstructing the mechanism of death, as well as the dynamics of the event.     

听力测试组合在听觉障碍鉴定中的应用

目的分析不同听力测试方法对听阈评估的作用,探讨组合听力测试在听觉障碍法医学鉴定中的应用。方法对87例外伤后听力损伤者进行听力测试,将纯音听阈测试(PTA)、声导抗、40HzAERP、ABR、ASSR、DPOAEs进行组合。听阈评估采用PTA+ABR+40HzAERP/ASSR,损伤定位采用PTA+声导抗+ABR/40HzAERP+DPOAEs。根据致伤方式的不同,分为头部损伤组和耳损伤组。比较组间DPOAEs阳性率,比较纯音听阈、40HzAERP、ABR及ASSR对听阈评估的作用。结果头部外伤组DPOAEs阳性率明显高于耳损伤组(P<0.05);纯音语频听阈异常耳与40HzAERP语频阈值及ABR比较,纯音语频阈值异常率较40HzAERP及ABR明显高,主、客观听阈明显不符。26耳40HzAERP与ASSR比较,两者在0.5kHz、1kHz、2kHz反应阈均值数相关性较好(r=0.862),ASSR语频均值较40HzAERP低,平均差17dB。结论纯音听阈与ABR、40HzAERP或ASSR组合测试对听阈的评估有互补作用。40HzAERP与ASSR均可以用于语音频率的听阈评估。声导抗、ABR、40HzAERP与DPOAEs多项检查组合,有助于确定损伤部位。     

Examination of Hacking and Blunt Force Skeletal Trauma

Hacking trauma is prevalent in forensic cases involving genocide and dismemberment, but research into the identification of this type of trauma is lacking. The present study examines characteristics of hacking and blunt force skeletal trauma in order to determine if there is a point at which blunt force trauma becomes distinguishable from hacking trauma. Ten implements with a range of blade angles (i.e., the striking surface of the implement) were used in conjunction with a controlled-force hacking device to impact 100 limb bones of white-tailed deer (Odocoileus virginianus). Observations of the trauma included the occurrence and degree of fragmentation, the entrance widths of the impacts, and composite scores of six hacking characteristics, especially the distinctive V-shaped kerf. ANOVA tests and regression analyses were used to assess the relationships between these characteristics and the blade angles. A significant relationship (p-value = 0.011) was found between the composite hacking scores and the blade angles, indicating that blunt force and hacking trauma can be distinguished. The entrance widths of the impacts exhibited a significant relationship with the blade angles (p-value = 0.037). There was also a significant relationship between the visibility of a V-shaped kerf in the bones (p-value = 0.003), with visibility decreasing around the 60° blade angle. These data should assist in establishing guidelines to differentiate hacking and blunt force skeletal trauma in cases where the implement is on a spectrum between sharp and blunt.     

The Erratic Behavior of Lesions in Burnt Bone

This study analyses depressed fractures (by blunt force trauma) and circular full‐thickness injuries (drill injuries and gunshot wounds) in charred bones. Fifty bovine ribs (total 104 lesions) were divided into three groups. The first group consisted in 20 depressed hammer‐produced fractures; in the second one, 60 round drill‐holes were produced (30 circular, 30 semicircular); in the third group, 12 fleshed and 12 skeletonized ribs were hit by 9‐mm bullets. Each specimen was carbonized in an electric oven up to 800°C. Morphological and metric analyses were performed before and after: morphological features were preserved, but depressed fractures showed an increase in their dimensions (p‐value < 0.05); the drilled holes shrunk (p‐value < 0.01); the charring cycle increased the number of fractures in samples with gunshot wounds differently in fleshed and defleshed ribs. This study showed the complex behavior of charred bone, for what concerns the interpretation of trauma and how caution should be applied.     

Laminated safety glass as an intermediate target: a wound ballistic study

Various 9‐mm ammunitions (A1, A4, A5, ST, GS, GSb, P.E.P., SeCa, HP, PTP/s, VM, McVG, DM41, PTP, SX2, PT, and MEN frangible) were tested regarding their velocity, energy, angle of impact, and potential wound channel after penetrating a car window at 30° and 90°. Test materials were gelatine, soap, and pig cadavers. The velocities of the projectiles were between c. 288 and 430 m/ses, the energy spread between 394 and 564 J. Handgun bullets fired through vehicular side window glass lose substantial energy reducing the effectiveness of the ammunition. This effect is greater when fired at an angle of 30° compared to 90°. At a shooting angle of 90°, none of the different projectiles showed remarkable differences considering its wound ballistic features. Accuracy is maintained at a 90° angle but seriously impaired at 30°. None of the examined ammunition complied with the demanded wound channel effectiveness of 30–60 J/cm.     

The Physical Effects of Contact and Close‐Distance Gunfire on Sweatshirt Fleece

Powder stippling caused by the impact of propellant particles during close‐distance gunfire has been previously described on skin and solid objects only. Additionally, radial tearing has been described as clear evidence of a contact‐distance shot, requiring no further testing. Patterns of discrete perforating holes (referred to here as “stippling perforations”) and other physical damage on sweatshirt fleece fabrics were prepared. Using the firearm and ammunition in this study, stippling perforations were observed to a maximum muzzle‐to‐target distance of 35 cm (10 inches). In addition, radial tearing and disintegration were present (and often more extensive) at greater than contact distance. The presence of stippling perforations could augment muzzle‐to‐target distance estimates generated using the Griess test, or allow distance estimates when the Griess test is not feasible. Unlike what has been previously reported, testing on the original evidence (or similar substitute) is warranted when physical damage is used to estimate shooting distance.     

Effects of kinetic energy and firearm-to-target distance on fracture behavior in flat bones

This research implements a fractographic approach to investigate the relationships between kinetic energy, firearm-to-target distance, and various aspects of fracture behavior in gunshot trauma. Gunshot experiments were performed on pig scapulae (n = 30) using three firearms generating different muzzle (initial) kinetic energies, including a 0.32 pistol (103 J), 0.40 pistol (492 J), and 0.308 rifle (2275 J). Specimens were shot from two distances: 10 cm (n = 15) and 110 cm (n = 15). Features evaluated in fractographic analysis such as cone cracks, radiating cracks, crack branching points, and circumferential cracks could be easily identified and measured in flat bones and allowed for statistical comparison of crack propagation behavior under different impact conditions. Higher-energy bullets produced more radiating cracks, more crack branching points, and longer fracture lengths than lower-energy bullets. Distance had no significant effect on fracture morphology at the distances tested. That quantitative measures of crack propagation varied with energy affirms that kinetic energy transfer is important in determining the nature and extent of fracture in gunshot wounds and suggests it may be possible to infer relatively high- versus relatively low-energy transfer using these features. Ranges obtained with the three firearms exhibited considerable overlap, however, indicating that other variables such as bullet caliber, mass, and construction influence the efficiency of energy transfer from bullet to bone. Therefore, fracture morphology cannot be used to identify a specific firearm or to directly reconstruct the muzzle (initial) kinetic energy in forensic cases.     

Skeletal Trauma Resulting From Fatal Low (≤3 m) Free Falls: An Analysis of Fracture Patterns and Morphologies

The skeletal trauma resulting from fatal low (≤3 m) free falls is poorly researched and understood by forensic practitioners. The aim of this study was to identify the types of skeletal trauma resulting from low falls through investigating fracture patterns and morphologies. Skeletal trauma was analyzed using full‐body postmortem computed tomography scans of 145 individuals who died from a low free fall. Trauma was then contextualized to the variables that influence how a person falls using multiple logistic regression. Results showed fracture patterning primarily involved the axial skeleton and that there were a number of patterns significantly associated with the height fallen, pre‐existing health conditions, and age. Analysis of fracture morphologies showed 108 possible fracture types, six of which were significantly associated with the height fallen. Understanding the skeletal trauma characteristic of low free falls will further inform anthropological interpretations of trauma in cases where a fall may be considered the possible mechanism.     

Histologic evidence of repetitive blunt force abdominal trauma in four pediatric fatalities

In cases of acute fatal child abuse, certain injuries, including cutaneous blunt force trauma, skull fractures, subdural hematomas, intra-abdominal hemorrhage, and retinal hemorrhages are common and well described in the pediatric and forensic literature. These gross findings at autopsy, when taken into consideration with scene investigation and interviews with caregivers, may indicate both a clear manner and cause of death. In such cases, the discovery of additional pathologic changes attributable to older abusive injuries helps support a conclusion of death due to inflicted trauma. We discuss four cases of fatal child abuse in which acute blunt force abdominal trauma was the cause of death. In each of these cases, careful examination with proper sectioning and microscopy of select abdominal tissues revealed that the acute tissue trauma was superimposed on a background of older, healing injury. This older trauma was characterized by classic histologic elements of tissue repair, including fibroblast proliferation, early scar formation, increased vascularity, and hemosiderin-laden macrophages. Iron and trichrome stains were used to confirm the presence of hemosiderin and fibrosis in all four cases, but the recognition of fibroblast proliferation and a reactive vascular pattern was best seen on routine hematoxylin and eosin stains. The gross and microscopic autopsy findings, along with available investigative information, established the diagnosis of chronic physical abuse.     

The Forensic Implications of Amphetamine Intoxication in Cases of Inflicted Blunt Craniocerebral Trauma

The effects of D‐amphetamine on outcome after blunt craniocerebral trauma are characterized and the potential legal implications discussed. Traumatic brain injury (TBI) was induced under general anesthesia in adult, male Sprague Dawley rats using the impact acceleration model. At 10 min prior to injury, D‐amphetamine (5 mg/kg) or saline vehicle was administered subcutaneously; animals were subsequently assessed over a 7‐day period post‐trauma for motor outcome using a rotarod device. D‐amphetamine treated animals performed significantly better (p < 0.001; ANOVA) than vehicle treated controls on their motor assessment, suggesting that D‐amphetamine exposure prior to injury either is neuroprotective or enhances motor performance. It is possible, therefore, that an individual who has taken amphetamines may function at a better motor level after head trauma than one who has not been exposed to the drug. Future interpretations of the potential effects of amphetamines on TBI should include this possibility.     

Manual and Automated Cardiopulmonary Resuscitation (CPR): A Comparison of Associated Injury Patterns,

The purpose of this study was to identify and compare patterns of trauma associated with AutoPulse^® CPR and manual CPR. Finalized autopsy records from 175 decedents brought to the Harris County Institute of Forensic Sciences were reviewed, 87 received manual‐only CPR, and 88 received AutoPulse^® CPR (in combination with manual CPR as per standard protocol). The characteristic pattern observed in manual‐only CPR use included a high frequency of anterior rib fractures, sternal fractures, and midline chest abrasions along the sternum. The characteristic pattern observed in AutoPulse^® CPR use included a high frequency of posterior rib fractures, skin abrasions located along the anterolateral chest and shoulder, vertebral fractures, and a few cases of visceral injuries including liver lacerations, splenic lacerations, and hemoperitoneum. Knowledge of the AutoPulse^® CPR injury pattern can help forensic pathologists differentiate therapeutic from inflicted injuries and therefore avoid an erroneous assessment of cause and manner of death.     

92式手枪射入口形态特征与射击距离的关系

目的研究手枪射入口形态特征与射击距离的关系,为射击距离的推断提供依据。方法选择92式手枪,在带皮的猪肉上覆盖白色棉布,设计了0m,0.1m,0.2m,0.5m1.0m,1.5m,3.0m,5.0m,10m,15.0m,20.0m,25.0m共12个射击距离,对白棉布和肉皮上的弹孔进行拍照,对比研究不同射击距离的射入口形态特征,并利用Autocad软件对射入口的面积进行计算。结果白棉布和肉皮上射入口的形态特征与射击距离有一定的相关性。结论根据射入口的形态特征,能够对射击距离进行推断,对涉枪案件中射击距离的判断有参考价值。     

Study of the Behaviors of Gunshot Residues from Spent Cartridges by Headspace Solid‐Phase Microextraction–Gas Chromatographic Techniques

Gunshot residues, produced after shooting activity, have acquired their importance in analysis due to the notoriety of firearms‐related crimes. In this study, solid‐phase microextraction was performed to extract the headspace composition of spent cartridges using 85‐μm polyacrylate fiber at 66°C for 21 min. Organic compounds, that is, naphthalene, 2,6‐dinitrotoluene, 2,4‐dinitrotoluene, diphenylamine, and dibutyl phthalate were detected and analyzed by gas chromatography‐flame ionization detection technique. Evaluation of chromatograms for diphenylamine, dibutyl phthalate, and naphthalene indicates the period after a gunshot was discharged, whether it was 1 days, 2–4 days, <5 days, 10 days, 20 days, or more than 30 days ago. This study revealed the potential effects of environmental factors such as occasional wind blow and direct sunlight on the estimation of time after spent cartridges were discharged. In conclusion, we proposed reliable alternative in analyzing the headspace composition of spent cartridges in a simulated crime scene.     

Patterns of Trauma Induced by Motorboat and Ferry Propellers as Illustrated by Three Known Cases from Rhode Island*

Abstract: Understanding patterns of trauma is important to determining cause and manner of death. A thorough evaluation of taphonomy, trauma, and bone fracture mechanisms is necessary to reconstruct the circumstances of the death. This study examines the skeletal trauma caused by boat propeller strikes in terms of wound characteristics and location based on three cases from Rhode Island. These case studies review the traumatic characteristics caused by propeller injuries and highlight the anatomic regions most likely to sustain skeletal trauma. With this information, investigators may be able to identify propeller trauma even in severely decomposed remains. The discussion of boat propeller trauma also raises issues regarding how forensic anthropologists and forensic pathologists classify trauma (specifically blunt force vs. sharp) and highlights semantic issues arising in trauma classification. The study also discusses why these propeller cases should be classified as blunt trauma rather than sharp or chop/hack trauma. Ultimately, the authors urge consistency and communication between pathologist and forensic anthropologists performing trauma analyses.     

An Assessment of the Skeletal Fracture Patterns Resulting from Fatal High (˃3 m) Free Falls

The injury patterns resulting from fatal high (?3 m) free falls have previously been documented in clinical and medico‐legal contexts; however, details relating specifically to the skeletal blunt force trauma (BFT) have been limited. This study aimed to augment what is known of the skeletal fracture patterns resulting from fatal high free falls. Skeletal trauma was analyzed from full‐body postmortem computed tomography scans of 95 individuals who died following a high free fall. Fracture patterns were documented using the five general anatomical regions, axial and appendicular regions, and postcranial unilateral and bilateral regions. Patterns were analyzed in the context of the extrinsic and intrinsic variables that may influence fractures using multiple logistic regression. Fracture patterns involved all aspects of the skeleton, with 98.9% exhibiting polytrauma, and were influenced primarily by the height fallen, manner of death, and landing surface. This improved understanding of fracture patterns will augment anthropological interpretations of the mechanism of BFT in cases of suspected high falls.     

根据霰弹丸分布图形推断射击距离的实验研究

目的 建立推断制式霰弹猎枪射击距离的数学计算公式和方法。方法 选用国产制式12号及16号猎枪,配用1号及3号猎枪弹,以1至12m距离射击实验靶纸,获得霰弹分布图形360例,将图形测量数据与实验距离进行数学理论分析。结果 建立6种不同枪弹种类推断射击距离d的计算公式,分别为12-1型(缩口)ss=-0.2+0.44d;12-1型(无缩口)ss=-0.94+0.63d;12-3型(缩口)ss=-0.59+0.52d;12-3型(无缩口)ss=-0.36+0.34d;16-1型s=-0.37+0.30d;16-3型s=-0.16+0.23d,并用Visual Basic5.0软件编制通用程序汇总软件。结论 本研究建立的方法简单实用,误差较小,可以用于推断制式猎枪的射击距离。