Inconsistency in 9 mm bullets : correlation of jacket thickness to post-impact geometry measured with non-destructive X-ray computed tomography

Fundamental to any ballistic armour standard is the reference projectile to be defeated. Typically, for certification purposes, a consistent and symmetrical bullet geometry is assumed, however variations in bullet jacket dimensions can have far reaching consequences. Traditionally, characteristics and internal dimensions have been analysed by physically sectioning bullets – an approach which is of restricted scope and which precludes subsequent ballistic assessment. The use of a non-destructive X-ray computed tomography (CT) method has been demonstrated and validated Kumar et al., 2011); the authors now apply this technique to correlate bullet impact response with jacket thickness variations. A set of 20 bullets (9 mm DM11) were selected for comparison and an image-based analysis method was employed to map jacket thickness and determine the centre of gravity of each specimen. Both intra- and inter-bullet variations were investigated, with thickness variations of the order of 200 um commonly found along the length of all bullets and angular variations of up to 50 um in some. The bullets were subsequently impacted against a rigid flat plate under controlled conditions (observed on a high-speed video camera) and the resulting deformed projectiles were re-analysed. The results of the experiments demonstrate a marked difference in ballistic performance between bullets from different manufacturers and an asymmetric thinning of the jacket is observed in regions of pre-impact weakness. The conclusions are relevant for future soft armour standards and provide important quantitative data for numerical model correlation and development. The implications of the findings of the work on the reliability and repeatability of the industry standard V50 ballistic test are also discussed

The cutting edge - Micro-CT for quantitative toolmark analysis of sharp force trauma to bone

Toolmark analysis involves examining marks created on an object to identify the likely tool responsible for creating those marks (e.g., a knife). Although a potentially powerful forensic tool, knife mark analysis is still in its infancy and the validation of imaging techniques as well as quantitative approaches is ongoing. This study builds on previous work by simulating real-world stabbings experimentally and statistically exploring quantitative toolmark properties, such as cut mark angle captured by micro-CT imaging, to predict the knife responsible. In Experiment 1 a mechanical stab rig and two knives were used to create 14 knife cut marks on dry pig ribs. The toolmarks were laser and micro-CT scanned to allow for quantitative measurements of numerous toolmark properties. The findings from Experiment 1 demonstrated that both knives produced statistically different cut mark widths, wall angle and shapes. Experiment 2 examined knife marks created on fleshed pig torsos with conditions designed to better simulate real-world stabbings. Eight knives were used to generate 64 incision cut marks that were also micro-CT scanned. Statistical exploration of these cut marks suggested that knife type, serrated or plain, can be predicted from cut mark width and wall angle. Preliminary results suggest that knives type can be predicted from cut mark width, and that knife edge thickness correlates with cut mark width. An additional 16 cut marks walls were imaged for striation marks using scanning electron microscopy with results suggesting that this approach might not be useful for knife mark analysis. Results also indicated that observer judgements of cut mark shape were more consistent when rated from micro-CT images than light microscopy images. The potential to combine micro-CT data, medical grade CT data and photographs to develop highly realistic virtual models for visualisation and 3D printing is also demonstrated. This is the first study to statistically explore simulated real-world knife marks imaged by micro-CT to demonstrate the potential of quantitative approaches in knife mark analysis. Findings and methods presented in this study are relevant to both forensic toolmark researchers as well as practitioners. Limitations of the experimental methodologies and imaging techniques are discussed, and further work is recommended

Design and experimental characterization of a tunable vibration-based electromagnetic micro-generator

Vibration-based micro-generators, as an alternative source of energy, have become increasingly significant in the last decade. This paper presents a new tunable electromagnetic vibration-based micro-generator. Frequency tuning is realized by applying an axial tensile force to the micro-generator. The dimensions of the generator, especially the dimensions of the coil and the air gap between magnets, have been optimized to maximize the output voltage and power of the micro-generator. The resonant frequency has been successfully tuned from 67.6 to 98 Hz when various axial tensile forces were applied to the structure. The generator produced a power of 61.6–156.6 µW over the tuning range when excited at vibrations of 0.59 ms-2. The tuning mechanism has little effect on the total damping. When the tuning force applied on the generator becomes larger than the generator’s inertial force, the total damping increases resulting in reduced output power. The resonant frequency increases less than indicated from simulation and approaches that of a straight tensioned cable when the force associated with the tension in the beam becomes much greater than the beam stiffness. The test results agree with the theoretical analysis presented

Synthetic Vision for Lunar and Planetary Landing Vehicles

The Crew Vehicle Interface (CVI) group of the Integrated Intelligent Flight Deck Technologies (IIFDT) has done extensive research in the area of Synthetic Vision (SV), and has shown that SV technology can substantially enhance flight crew situation awareness, reduce pilot workload, promote flight path control precision and improve aviation safety. SV technology is being extended to evaluate its utility for lunar and planetary exploration vehicles. SV may hold significant potential for many lunar and planetary missions since the SV presentation provides a computer-generated view of the terrain and other significant environment characteristics independent of the outside visibility conditions, window locations, or vehicle attributes. SV allows unconstrained control of the computer-generated scene lighting, terrain coloring, and virtual camera angles which may provide invaluable visual cues to pilots/astronauts and in addition, important vehicle state information may be conformally displayed on the view such as forward and down velocities, altitude, and fuel remaining to enhance trajectory control and vehicle system status. This paper discusses preliminary SV concepts for tactical and strategic displays for a lunar landing vehicle. The technical challenges and potential solutions to SV applications for the lunar landing mission are explored, including the requirements for high resolution terrain lunar maps and an accurate position and orientation of the vehicle that is essential in providing lunar Synthetic Vision System (SVS) cockpit displays. The paper also discusses the technical challenge of creating an accurate synthetic terrain portrayal using an ellipsoid lunar digital elevation model which eliminates projection errors and can be efficiently rendered in real-time

Enhanced/Synthetic Vision and Head-Worn Display Technologies for Terminal Maneuvering Area NextGen Operations

NASA is researching innovative technologies for the Next Generation Air Transportation System (NextGen) to provide a "Better-Than-Visual" (BTV) capability as adjunct to "Equivalent Visual Operations" (EVO); that is, airport throughputs equivalent to that normally achieved during Visual Flight Rules (VFR) operations rates with equivalent and better safety in all weather and visibility conditions including Instrument Meteorological Conditions (IMC). These new technologies build on proven flight deck systems and leverage synthetic and enhanced vision systems. Two piloted simulation studies were conducted to access the use of a Head-Worn Display (HWD) with head tracking for synthetic and enhanced vision systems concepts. The first experiment evaluated the use a HWD for equivalent visual operations to San Francisco International Airport (airport identifier: KSFO) compared to a visual concept and a head-down display concept. A second experiment evaluated symbology variations under different visibility conditions using a HWD during taxi operations at Chicago O'Hare airport (airport identifier: KORD). Two experiments were conducted, one in a simulated San Francisco airport (KSFO) approach operation and the other, in simulated Chicago O'Hare surface operations, evaluating enhanced/synthetic vision and head-worn display technologies for NextGen operations. While flying a closely-spaced parallel approach to KSFO, pilots rated the HWD, under low-visibility conditions, equivalent to the out-the-window condition, under unlimited visibility, in terms of situational awareness (SA) and mental workload compared to a head-down enhanced vision system. There were no differences between the 3 display concepts in terms of traffic spacing and distance and the pilot decision-making to land or go-around. For the KORD experiment, the visibility condition was not a factor in pilot's rating of clutter effects from symbology. Several concepts for enhanced implementations of an unlimited field-of-regard BTV concept for low-visibility surface operations were determined to be equivalent in pilot ratings of efficacy and usability

The simulation of action disorganisation in complex activities of daily living

Action selection in everyday goal-directed tasks of moderate complexity is known to be subject to breakdown following extensive frontal brain injury. A model of action selection in such tasks is presented and used to explore three hypotheses concerning the origins of action disorganisation: that it is a consequence of reduced top-down excitation within a hierarchical action schema network coupled with increased bottom-up triggering of schemas from environmental sources, that it is a more general disturbance of schema activation modelled by excessive noise in the schema network, and that it results from a general disturbance of the triggering of schemas by object representations. Results suggest that the action disorganisation syndrome is best accounted for by a general disturbance to schema activation, while altering the balance between top-down and bottom-up activation provides an account of a related disorder - utilisation behaviour. It is further suggested that ideational apraxia (which may result from lesions to left temporoparietal areas and which has similar behavioural consequences to action disorganisation syndrome on tasks of moderate complexity) is a consequence of a generalised disturbance of the triggering of schemas by object representations. Several predictions regarding differences between action disorganisation syndrome and ideational apraxia that follow from this interpretation are detailed

Cortical bony thickening of the lateral intercondylar wall : the functional attachment of the anterior cruciate ligament

Background: The anatomy of the anterior cruciate ligament (ACL) has become the subject of much debate. There has been extensive study into attachment points of the native ligament, especially regarding the femoral attachment. Some of these studies have suggested that fibers in the ACL are of differing functional importance. Fibers with higher functional importance would be expected to exert larger mechanical stress on the bone. According to Wolff’s law, cortical thickening would be expected in these areas. Purpose: To examine cortical thickening in the region of the ACL footprint (ie, the functional footprint of the ACL). Study Design: Descriptive laboratory study. Methods: Using micro–computed tomography with resolutions ranging from 71 to 91 μm, the cortical thickness of the lateral wall of the intercondylar notch in 17 cadaveric knees was examined, along with surface topography. After image processing, the relationship between the cortical thickening and surface topology was visually compared. Results: A pattern of cortical thickening consistent with the functional footprint of the ACL was found. On average, this area was 3 times thicker than the surrounding bone and significantly thicker than the remaining lateral wall (P < .0001). This thickening was roughly elliptical in shape (with a mean centroid at 23.5 h:31 t on a Bernard and Hertel grid) and had areas higher on the wall where greater thickness was present. The relationship to previously reported osseous landmarks was variable, although the patterns were broadly consistent with those reported in previous studies describing direct and indirect fibers of the ACL. Conclusion: The findings of this study are consistent with those of recent studies describing fibers in the ACL of differing functional importance. The area in which the thickening was found has been defined and is likely to represent the functional footprint of the ACL

Novel application of three-dimensional technologies in a case of dismemberment

This case study reports the novel application of three-dimensional technologies such as micro-CT and 3D printing to the forensic investigation of a complex case of dismemberment. Micro-CT was successfully employed to virtually align severed skeletal elements found in different locations, analyse tool marks created during the dismemberment process, and virtually dissect a charred piece of evidence. High resolution 3D prints of the burnt human bone contained within were created for physical visualisation to assist the investigation team. Micro-CT as a forensic radiological method provided vital information and the basis for visualisation both during the investigation and in the subsequent trial making it one of the first examples of such technology in a UK court

Together, yet still not equal? Sex integration in equestrian sport

Sex segregation is a core organising principle of most modern sports and is a key element in the marginalisation and subordination of girls and women in sport and beyond. In this article I explore the only Olympic-level sport which is not organised around sex segregation – equestrian sport – in order to consider the implications of sex integration for female participants. I draw on a study conducted on elite riders that found that although sex integration in equestrian sport does not lead to female participants being excluded from high-level competition, men continue to perform disproportionately well. This suggests that although sex integration may be an important step towards breaking down gender hierarchies in sport, without accompanying wider changes in gender norms and expectations, sex integration alone will not be enough to achieve greater gender equality in equestrian sport