Development of a Novel Finger-Trigger Interface for Trigger Pull Measurement

Trigger pull is the force that needs to be exerted on the trigger to discharge a firearm. The measurement of trigger pull can assist in the evaluation of the safety, function, and manufacturing characteristics associated with a firearm during the forensic firearm examination process. Nonetheless, the accuracy and uncertainty of trigger pull measurements may be affected by the measuring device, test procedure, and environmental conditions. In this work, an innovative finger-trigger interface device was developed to facilitate accurate trigger pull measurements. The idea was to reduce the variation related to the position of the measurement device on the trigger in existing measuring methods and devices. Three force sensors based on different technologies were initially evaluated. While two of the three sensors failed to produce data, the miniature capacitive plate sensor exhibited high precision and a linear response over the range of typical trigger pulls. To examine the effects of the finger-trigger interface on trigger pull measurement, different sensor housing prototypes were designed in silico and 3D printed for the construction of three finger-trigger interface devices. The performance of each finger-trigger interface device was evaluated by measuring the trigger pulls of several selected firearms and comparing the data to a previously published study. Our preliminary results demonstrated the novel finger-trigger interface device offered a new way to measure trigger pull in situ with acceptable accuracy and precision.     

Bank security dye packs: synthesis, isolation, and characterization of chlorinated products of bleached 1-(methylamino)anthraquinone

Banknote evidence is often submitted after a suspect has attempted to disguise or remove red dye stain that has been released because of an anti-theft device that activates after banknotes have been unlawfully removed from bank premises. Three chlorinated compounds have been synthesized as forensic chemical standards to indicate bank security dye bleaching as a suspect's intentional method for masking a robbery involving dye pack release on banknotes. A novel, facile synthetic method to provide three chlorinated derivatives of 1-(methylamino)anthraquinone (MAAQ) is presented. The synthetic route involved Ultra Clorox bleach as the chlorine source, iron chloride as the catalyst, and MAAQ as the starting material and resulted in a three-component product mixture. Two mono-chlorinated isomers (2-chloro-1-(methylamino)anthraquinone and 4-chloro-1-(methylamino)anthraquinone) and one di-chlorinated compound (2,4-dichloro-1-(methylamino)anthraquinone) of the MAAQ parent molecule were detected by gas chromatography mass spectrometry (GC-MS), and subsequently isolated by liquid chromatography (LC) with postcolumn fraction collection. Although GC-MS is sensitive enough to detect all of the chlorinated products, it is not definitive enough to identify the structural isomers. Liquid-state nuclear magnetic resonance (NMR) spectroscopy was utilized to elucidate structurally the ortho- and para-mono-chlorinated isomers once enough material was properly isolated. A reaction mechanism involving iron is proposed to explain the presence of chlorinated MAAQ species on stolen banknotes after attempted bleaching.     

Forensic analysis of smart TV: A current issue and call to arms

A number of new entertainment systems have appeared on the market that have embedded computing capabilities. Smart Televisions have the ability to connect to networks, browse the web, purchase applications and play games. Early versions were based on proprietary operating systems; newer versions released from 2012 are based on existing operating systems such as Linux and Android. The question arises as to what sort of challenges and opportunities they present to the forensics examiner. Are these new platforms or simply new varieties of existing forms of devices? What data do they retain and how easy is it to access this data? This paper explores this as a future forensic need and asks if we are missing potential sources of forensic data and to what degree we are ready to process these systems as part of an investigation.     

Windows Surface RT tablet forensics

Small scale digital device forensics is particularly critical as a result of the mobility of these devices, leading to closer proximity to crimes as they occur when compared to computers. The Windows Surface tablet is one such device, combining tablet mobility with familiar Microsoft Windows productivity tools. This research considers the acquisition and forensic analysis of the Windows Surface RT tablet. We discuss the artifacts of both the Windows RT operating system and third-party applications. The contribution of this research is to provide a road map for the digital forensic examination of Windows Surface RT tablets.     

Evaluation of canine training aids containment for homemade explosive and components by headspace analysis and canine testing

While canines are most commonly trained to detect traditional explosives, such as nitroaromatics and smokeless powders, homemade explosives (HMEs), such as fuel–oxidizer mixtures, are arguably a greater threat. As such, it is imperative that canines are sufficiently trained in the detection of such HMEs. The training aid delivery device (TADD) is a primary containment device that has been used to house HMEs and HME components for canine detection training purposes. This research assesses the odor release from HME components, ammonium nitrate (AN), urea nitrate (UN), and potassium chlorate (PC), housed in TADDs. Canine odor recognition tests (ORTs) were used with analytical data to determine the detectability of TADDs containing AN, UN, or PC. Headspace analysis by gas chromatography/mass spectrometry (GC/MS) with solid-phase microextraction (SPME) or online cryotrapping were used to measure ammonia or chlorine, as well as other unwanted odorants, emanating from bulk AN, UN, and PC in TADDs over 28 weeks. The analytical data showed variation in the amount of ammonia and chlorine over time, with ammonia from AN and UN decreasing slowly over time and the abundance of chlorine from PC TADDs dependent on the frequency of exposure to ambient air. Even with these variations in odor abundance, canines previously trained to detect bulk explosive HME components were able to detect all three targets in glass and plastic TADDs for at least 18 months after loading. Detection proficiency ranged from 64% to 100% and was not found to be dependent on either age of material.     

二战后初期日本民间掳日劳工遗骨送还运动

战后初期,日本民间14个团体组成的中国战俘殉难者追悼执行委员会为督促日本政府尽快解决掳日劳工遗骨送还问题,积极开展劳工遗骨调查、追悼活动,并与政府进行交涉,促成了一批劳工遗骨的归国。日本政府相对于民间团体积极解决问题的态度,则呈现出"不承认""不作为""与政府无关"的敷衍态度。日本民间和平团体开展的掳日劳工遗骨送还运动推进了中日邦交正常化的进程。正是因为战后初期特殊的国际局势与中日关系,致使掳日劳工遗骨归还问题逐步演变为战争遗留问题。     

超滤管在陈旧生物检材中的应用

目的探讨millipore超滤管滤过方法对陈旧生物检材DNA分型检验的应用价值。方法将23份陈旧血样分别剪取同样合适大小的血片3组,标为A、B、C组,磁珠法提取DNA,分别用80μL、80μL、20μL洗脱液洗脱得到模板DNA,其中A、C组模板直接扩增,B组用millipore超滤管滤过浓缩后扩增。PCR产物用AB3130x L基因分析仪检测,Gene Mapper ID V3.2软件进行自动分型。所得实验数据用SPSS软件分析处理。结果 A组没有1例样本扩出全部STR基因座,B组有18例样本扩出全部STR基因座,C组有11个样本扩出全部STR基因座。结论应用millipore超滤管滤过方法可以明显提高陈旧生物检材的DNA分型成功率。     

The characteristics of head wounds inflicted by "humane killer" (captive-bolt gun)--a 15-year study

The "humane killer" or captive-bolt gun, is the tool/weapon widely used in meat industry and private farmer households for slaughtering animal stock. Out of 17,250 autopsies performed at the Institute of Forensic Medicine in Novi Sad during the 15-year period (1991-2005), 29 cases of suicides and two homicides were committed by captive-bolt pistols. Wounds inflicted by captive-bolt guns have specific morphological features, distinctive from wounds made by other kinds of hand firearms. Selected features of the captive-bolt wounds (punched round entrance and a double pattern of smoke soiling) depend on distance and angle of instrument at the time of firing. Autopsy findings were compared with an experimental model consisting of 20 domestic pigs. Obtained results confirmed that the appearance of the entrance hole and soot deposits, along with differences in shape, location, extent, and density of soot blackening, could be useful in identification of weapon, direction of discharge, shooting distance, and angle of the muzzle to the frontal and sagittal planes of the head at the moment of fire.     

The Effects of Continuous Application of the TASER X26 Waveform on Sus scrofa,

This study investigated and evaluated the safety margins of the continuous long duration (up to 30 min) effect of the TASER X26 waveform, using a Sus scrofa model. Long duration continuous stimulus has not been evaluated on humans or human surrogates prior to this study. Swine were used as models due to similarities with humans in their skin and cardiovascular systems. Very long duration was used to determine both exposure dose and possible adverse physiological effects of dose. The trial began with an application of 10 min, and subsequent animals received increasing exposure time up to a survived maximum duration of 30 min. At the onset of this work, it was hypothesized that there would be a time limit after which most animals would not survive consistent with increased dose response. However, this hypothesis was not supported by the experimental results. All animals (10 of 10) survived up to 3 min. Seven of the 10 animals survived up to a 10‐min exposure and 3 of 5 animals with a 30‐min target exposure survived the full exposure. Surviving animals were recovered and observed for 24 h, with no postrecovery deaths. This suggests that swine (based on physiology) will not experience a fatal event when exposed to the TASER X26 for a continuous 3 min. Conclusions regarding longer duration (10–30 min) are not as certain due to the small sample sizes at these time intervals.     

The Role of the Chemical Weapons Convention in Countering Chemical Terrorism

A series of incidents over the past two decades has indicated that some terrorist groups are interested in acquiring and using improvised chemical devices (ICDs). Although the 1993 Chemical Weapons Convention (CWC) is a disarmament treaty that is legally binding only on sovereign states that join it voluntarily, the Convention fortuitously includes several provisions that can help its members to prevent chemical terrorism or to manage the consequences of an attack. This article examines the articles of the CWC that are relevant to counterterrorism and discusses how their implementation could be improved at the national and international levels. The article also addresses the role that the CWC secretariat, the Organization for the Prohibition of Chemical Weapons (OPCW) in The Hague, currently plays in preventing and responding to incidents of chemical terrorism, and the political factors that constrain its activities in the counterterrorism field.