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Forensic science plays a critical role in the United States criminal legal system. For decades, many featurebased fields of forensic science, such as firearm and toolmark identification, developed outside the scientific community’s purview. The results of these studies are widely relied on by judges nationwide. However, this reliance is misplaced. Black-box studies to date suffer from inappropriate sampling methods and high rates of missingness. Current black-box studies ignore both problems in arriving at the error rate estimates presented to courts. We explore the impact of each type of limitation using available data from blackbox studies and court materials. We show that black-box studies rely on unrepresentative samples of examiners. Using a case study of a popular ballistics study, we find evidence that these nonrepresentative samples may commit fewer errors than the wider population from which they came. We also find evidence that the missingness in black-box studies is non-ignorable. Using data from a recent latent print study, we show that ignoring this missingness likely results in systematic underestimates of error rates. Finally, we offer concrete steps to overcome these limitations. Supplementary materials for this article are available online. [ABSTRACT FROM AUTHOR]

As the epidemic of gunshot injuries and firearm fatalities continues to proliferate in the United States, knowledge regarding gunshot wound (GSW) injury and management is increasingly relevant to health-care providers. Unfortunately, existing guidelines are largely outdated, written in a time that high-velocity weapons and deforming bullets were chiefly restricted to military use. Advances in firearm technology and increased accessibility of military grade firearms to civilians has exacerbated the nature of domestic GSW injury and complicated clinical decision-making, as these weapons are associated with increased tissue damage and often result in retained bullets. Currently, there is a lack of literature addressing recent advances in the field of projectile-related trauma, specifically injuries with retained bullets. This review aims to aggregate the available yet dispersed findings regarding ballistics, GSW etiology, and treatment, particularly for cases involving retained projectiles. [ABSTRACT FROM AUTHOR]

Objectives: There are significant numbers of military and law enforcement bullets containing ferromagnetic materials. This study aimed to assess the magnetic field interactions for a representative sample of military and law enforcement ballistic objects at 1.5 and 3 tesla (T) to create a magnetic resonance imaging (MRI) compatibility database.Methods: Twenty-nine different bullets underwent MRI evaluation. The deflection angle method and a qualitative torque scale were used. The samples were representative of those commonly used in the North Atlantic Treaty Organization (NATO) military forces (e.g., 5.56 mm NATO), law enforcement agencies (e.g., 9 mm Parabellum), and encountered in war injuries and crime-related trauma (e.g., 7.62 mm Kalashnikov).Results: At all static magnetic field strengths, all non-nickel- and nonsteel-containing bullets exhibited no movement (deflection angle = 0°; torque = 0), whereas eight bullets containing steel core, steel jacket, or nickel jacket exhibited substantial magnetic field interactions over and above what might be regarded as safe in vivo (deflection angle = 90°; torque = 4+).Conclusion: Military and law enforcement non-nickel- or nonsteel-containing bullets appear to be safe for patients in MRI system at 1.5 and 3 T. On the other hand, nickel- and steel-containing bullets exhibit movements that are considered potentially unsafe for patients in an MRI environment. [ABSTRACT FROM AUTHOR]

The incidence of traumatic brain injuries (TBI) in the US has reached epidemic proportions with well over 2 million new cases reported each year. TBI can occur in both civilians and warfighters, with head injuries occurring in both combat and non-combat situations from a variety of threats, including ballistic penetration, acceleration, blunt impact, and blast. Most generally, TBI is a condition in which physical loads exceed the capacity of brain tissues to absorb without injury. More specifically, TBI results when sufficient external force is applied to the head and is subsequently converted into stresses that must be absorbed or redirected by protective equipment. If the stresses are not sufficiently absorbed or redirected, they will lead to damage of extracranial soft tissue and the skull. Complex interactions and kinematics of the head, neck and jaw cause strains within the brain tissue, resulting in structural, anatomical damage that is characteristic of the inciting insult. This mechanical trauma then initiates a neuro-chemical cascade that leads to the functional consequences of TBI, such as cognitive impairment. To fully understand the mechanisms by which TBI occurs, it is critically important to understand the effects of the loading environments created by these threats. In the following, a review is made of the pertinent complex loading conditions and how these loads cause injury. Also discussed are injury thresholds and gaps in knowledge, both of which are needed to design improved protective systems. [ABSTRACT FROM AUTHOR]

Abstract: Porous-ceramic, thermal protection systems were used heavily on the Orbiter, and they are currently being used on the next generation of US manned spacecraft, Orion. These systems insulate reentry critical components of a spacecraft against the intense thermal environments of atmospheric reentry. Additionally, these materials are highly exposed to space environment hazards like solid particle impacts. This paper discusses impact studies up to 10 km/s on nominally 8 lb/ft3 alumina-fiber-enhanced-thermal-barrier (AETB8) tiles coated with a toughened-unipiece-fibrous-insulation/reaction-cured-glass layer (TUFI/RCG). A first principles impact model that describes projectile dispersion is described that provides excellent agreement with observations over a broad range of impact velocities, obliquities and projectile materials.© 2012 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of the International Hypervelocity Impact Society. [Copyright &y& Elsevier]

Abstract: As evidenced by the recent experience of the US Armed Forces involved in the missions in Iraq and Afghanistan, armoring military-vehicle windshields and side windows is a very challenging task. Apart from providing the required single-hit and multi-hit ballistic protection to the vehicle occupants, the armor must also possess and retain optical transparency and be compatible with on-board imaging and communications equipment. In addition, standard low cost and light-weight requirements are also critical in the design and engineering of transparent armor systems. At the present time, the design and fabrication of transparent armor systems is done almost exclusively using empirical, trial-and-error and legacy approaches. Consequently, new transparent armor system development lead times are long, the costs are quite high and many shortcomings of the systems become apparent only after they have been fielded. To help better understand and overcome this situation, a brief overview and discussion of the basic transparent armor architectures, functional layers and transparent materials is provided and a set of design and material selection guidelines is proposed. [Copyright &y& Elsevier]

Analysis of ballistics evidence (spent cartridge casings and bullets) has been a staple of forensic criminal investigation for almost a century. Computer-assisted databases of images of ballistics evidence have been used since the mid-1980s to help search for potential matches between pieces of evidence. In this article, we draw on the 2008 National Research Council Report' Ballistic Imaging to assess the state of ballistic imaging technology. in particular, we discuss the feasibility of creating a national reference ballistic imaging database (RBID) from test-fires of all newly manufactured or imported firearms. A national RBID might aid in using crime scene ballistic evidence to generate investigative leads to a crime gun's point of sale. We conclude that a national RBID is not feasible at this time, primarily because existing imaging methodologies have insufficient discriminatory power. We also examine the emerging technology of microstamping for forensic identification purposes: etching a known identifier on firearm or ammunition parts so that they can be directly read and recovered from crime scene evidence. Microstamping could provide a stronger basis for identification based on ballistic evidence than the status quo, but substantial further research. is needed to thoroughly assess its practical viability. [ABSTRACT FROM AUTHOR]

Presents the study of the technological innovations for less-lethal kinetic energy munitions used in law enforcement in the U.S. Examinations taken to determine energy per unit area required to penetrate various regions of the body; Used of eight unembalmed postmortem human specimens in the testing experiment; Evaluation on the conducted test results.

The National Institute of Standards and Technology Standard Reference Material (SRM) 2460/2461 standard bullets and casings project will provide support to firearms examiners and to the National Integrated Ballistics Information Network (NIBIN) in the United States. The SRM bullet is designed as both a virtual and a physical bullet profile signature standard. The virtual standard is a set of six digitized bullet profile signatures originally traced from six master bullets fired at the Bureau of Alcohol, Tobacco and Firearms (ATF) and the Federal Bureau of Investigation (FBI). By using the virtual signature standard to control the tool path on a numerically controlled diamond turning machine, 40 SRM bullets were pro-duced. A profile signature measurement system was established for the SRM bul-lets. The profile signature differences are quantified by the maximum of the cross correlation function and by the signature difference between pairs of compared profile signatures measured on different SRM bullets. Initial measurement results showed high reproducibility for both the measurement system and production process of the SRM bullets. A traceability scheme has been proposed to establish the measurement traceability for nationwide bullet signature measurements to NIST, ATF and FBI. Prototype SRM casings have also been developed. [ABSTRACT FROM AUTHOR]

Examines the impact of ballistics imaging technology on the productivity of the Boston Police Department's Ballistic Unit. Value of ballistics imaging technology in law enforcement; Analysis of time series data with the use of negative binomial regression models; Results of cost-effectiveness estimates and qualitative evidence.

Reports on the development of a bullet signature measurement system based on a stylus instrument of the National Institute of Standards and Technology in the United States. Goal for the support of the National Integrated Ballistics Information Network; Set of digitized bullet signatures profiled from master bullets; Control of the tool path to qualify bullet signature differences.

This paper develops an analytical model for the ballistic impact response of fibrous materials of interest in body armor applications. It focuses on an un-tensioned 2D membrane impacted transversely by a blunt-nosed projectile, a problem that has remained unsolved for a half a century. Membrane properties are assumed characteristic of the best current body armor materials (Kevlar®, Spectra®, Zylon®, S2 glass), which have very high stiffness and strength per unit weight, and low strain-to-failure. Successful comparisons will be made with extensive experimental data on such material systems as reported by Cunniff [Decoupled response of textile body armor. Proc. 18th Int. Symp. of Ballistics, San Antonio, Texas, 1999a, pp. 814–821; Vs–Vr relationships in textile system impact. Proc. 18th Int. Symp. of Ballistics, San Antonio, Texas, 1999b; Dimensional parameters for optimization of textile-based body armor systems, Proc. 18th Int. Symp. of Ballistics, San Antonio, Texas, 1999c, pp. 1303–1310]. Our mathematical formulation draws on the seminal work of Rakhmatulin and Dem’yanov [Strength Under High Transient Loads, 1961, pp. 94–152]. Under constant projectile velocity we first develop self-similar solution forms for the tensile ‘implosion’ wave and the curved cone wave that develops in its wake. Through matching boundary conditions at the cone wave front, we obtain an accurate approximate solution for the membrane response including cone wave speed and strain distribution. We then consider projectile deceleration due to membrane reactive forces, and obtain results on cone velocity, displacement and strain concentration versus time. Other results obtained are the membrane ballistic limit, or V50 velocity, and the residual velocity when penetrated above this limit. We then derive an exact functional representation of a V50 ‘master curve’ found empirically by Cunniff [ibid] to reduce data for a wide variety of fabric systems impacted by blunt cylindrical projectiles. This curve is given in terms two dimensionless parameters based only on fiber mechanical properties and the ratio of the fabric areal density to the projectile mass divided by its area of fabric contact. Our functional representation has no fitting parameters beyond one reflecting uncertainty in the effective diameter of the impact zone relative to the projectile diameter, and even then the values are consistent across several experimental systems. The extremely successful comparison of our analytical model to experimental results in the literature raises fundamental questions about many long-held views on fabric system impact behavior and parameters thought to be important. [Copyright &y& Elsevier]

Focuses on a study that presented comparisons between high and low density cases for a number of ballistic parameters. Overview of the approach used to increase kinetic energy in the electrothermal-chemical guns in the United States; Description of gun system; Sensitivity to parameter changes; Conclusions.

This article presents updates on the field of criminal law and criminology in the U.S. as of July 1931. The University of North Carolina School of Law in conjunction with the Commission on Interracial Cooperation will be studying the problems confronting the law as a result of the prevalence of lynching, while as the National Probation Association, announces that the 1930 Year Book of the Association is ready for distribution. A variety of interesting topics is treated in the yearbook including the Status of Federal Probation, Probation Service Today,- Progress or Retrogression, The, Training and Recruiting of Probation Officers, and Trends of Probation. On the other hand, the School in Crime Detection conducted by the Scientific Crime Detection Laboratory of Northwestern University came to a successful close with a series of examinations including a test murder case involving a bullet-plugged dummy. The subjects studies included ballistics, toxicology, truth serum, lie detectors, firearm identification, psychology and chemistry in crime detection, handwriting, codes, serology, errors of eyewitnesses, medical fakes, fingers prints, microscopic work, riles of evidence and other phases of crime detection. Furthermore, two members of the Staff of the Crime Detection Laboratory are conducting extensive experiments with twilight sleep, induced by morphine and scopolamine, in an effort to detect deception.

The article discusses recent criminal decisions rendered by the U.S. courts. In a case on admissibility of expert testimony on ballistics, the defendant was indicted for first degree murder and upon a plea of not guilty was placed on trial and convicted of murder in the second degree. Testimony was admitted, over the objection of the defendant, of a witness who had made guns his "hobby'' and who identified the gun, admittedly used previously by defendant. The identification was made by comparison of the rifling of the revolver barrel with certain markings found on the fatal bullet. Held, on appeal, that the judgment be affirmed. A number of cases can now be cited in which there has been a decisive recognition of the admissibility of evidence based on the science of ballistics. A high degree of care in the determination of the qualifications of a proffered expert in this field is without doubt necessary. In certain cases, facts tending to identify the weapon used by the defendant have been testified to by so-called gun experts.

The article reports on the development of a ballistic computing transistor by a team of U.S. university researchers. University of Rochester professor Marc Feldman leads a team of experts in computer engineering, circuit design, computer architecture, and theoretical physics in working on the ballistic deflection transistor (BDT), a technology for creating ultra-fast, energy-efficient chips developed by Quentin Diduck. Some of the problems regarding transistor approaches dealt with by BDT technology are discussed.

Reports that a team of scientists from Georgia Institute of Technology has observed ballistic conductance, a phenomenon in which electrons pass trough a conductor without heating it. Details on the observation made by the team; Applications of the research; Description of the experiment.