Detecting Gunshot Residue from Sellier & Bellot Nontox Heavy Metal‐free Primer by in situ Cathodoluminescence

Gunshot residue (GSR) from the discharge of ammunition can provide crucial information in reconstructing criminal cases. Traditional primers create particles of heavy metals such as lead, barium, and antimony. In forensic laboratories, automatic inorganic particle detection is performed by scanning electron microscopy (SEM), using the backscattered electron signal to search for bright residues among the many darker environmental particles, due to higher electron density of the former. Some innovative primers, indicated as heavy metal‐free (HMF), produce a residue of elements with atomic numbers below 21, urgently demanding new detecting solutions. For the first time, residues from Sellier & Bellot Nontox HMF primer are demonstrated to emit visible light under electron beam stimulation in a SEM. Cathodoluminescence is then proposed as a promising tool to both detect and characterize residues in forensic cases involving HMF primers, with minor changes to traditional analytical apparatus used for inorganic GSR analysis.     

血、尿中金属毒物的电感耦合等离子发射光谱检测方法

目的建立血和尿中的有毒金属元素快速检测方法。方法通过模拟样品,采用微波消解炉对样品进行预处理,用电感耦合等离子发射光谱仪同时对多种可疑有毒金属元素进行检测。结果血、尿样品经消解或酸稀释处理,镉、钴、铬、铜、镍等元素可检测方法平均回收率范围为75.5%～127.5%,变异系数小于16.4%结论在中毒剂量,对肝脏和肾脏组织中的可疑有毒金属元素,可以采用电感耦合等离子发射光谱仪同时进行检测。     

中日在稀有金属领域的战略博弈——兼评中国稀土产业政策效果

日本本土稀有金属资源极度匮乏,但却是世界稀有金属消费大国和应用强国。随着稀有金属在战略性新兴产业应用日益广泛,中日两个稀有金属资源和应用大国在该领域展开了数轮博弈。为应对中国收紧稀有金属出口的一揽子政策措施,日本综合运用技术、经济、政治、外交手段,形成了以技术创新为核心、市场化为基本导向、官产学联动的稀有金属保障战略体系,有效缓解了其国内稀有金属供给趋紧的压力,进一步巩固了日本在稀有金属全球价值链上的竞争优势。长期以来,中国稀有金属的资源优势未能上升为产业优势。借鉴日本稀有金属保障体系,应加快构建稀有矿产资源国家战略,推动稀有金属产业链向高端环节延展,切实维护国家资源安全。     

Location and Assessment of an Historic (150–160 Years Old) Mass Grave Using Geographic and Ground Penetrating Radar Investigation,NW Ireland*

Abstract: Reburial of human remains and concerns regarding pathogens and pollution prompted the search for, and assessment of, a 156-year-old graveyard. To locate this graveyard, historic and anecdotal information was compared to landscape interpretation from aerial photography. To assess and map the contents, surface collapses, metal detector indications, and ground-penetrating radar (GPR) were used. Some 170 anomalies compatible with burials were identified on 200 MHz GPR data, 84 of which coincided with surface collapses, suggesting both noncollapsed ground, subsequent infill, and multiple inhumations. The graveyard was possibly split into Roman Catholic plots with multiple inhumations; Protestant plots; and a kileen, or graveyard for the unbaptized (often children). The work serves as one approach to the location and mapping of recent and historic unmarked graves.     

The unfortunate natural experiment in ballot design: The Scottish Parliamentary elections of 2007

The 2007 Scottish Parliamentary elections were notable for the extensive variation across constituencies in rejected ballots (ranging from 1.90% to 12.09%). This paper uses an unfortunate natural experiment to identify the influence of ballot design on the occurrence of rejected ballots, or ‘residual votes’. In two electoral regions, visual prompts were removed and instructions were abbreviated on the (already poorly designed) ballot papers. Using zero-truncated negative binomial regression to model total residual votes as well as constituency and regional undervotes and overvotes, we find clear evidence that these changes made a major contribution to the extent of residual votes in constituencies within those regions. The findings emphasise that ballot design is not a trivial subject that can be neglected by electoral administrators.     

Visualization of latent fingerprint corrosion of metallic surfaces

Abstract:  Chemical reactions between latent fingerprints and a variety of metal surfaces are investigated by heating the metal up to temperatures of ∼600°C after deposition of the fingerprint. Ionic salts present in the fingerprint residue corrode the metal surface to produce an image of the fingerprint that is both durable and resistant to cleaning of the metal. The degree of fingerprint enhancement appears independent of the elapsed time between deposition and heating but is very dependent on both the composition of the metal and the level of salt secretion by the fingerprint donor. Results are presented that show practical applications for the enhancement to fingerprints deposited in arson crime scenes, contaminated by spray painting, or deposited on brass cartridge cases prior to discharge. The corrosion of the metal surface is further exploited by the demonstration of a novel technique for fingerprint enhancement based on the electrostatic charging of the metal and then the preferential adherence of a metallic powder to the corroded part of the metal surface.     

A Modified Electrostatic Adsorption Apparatus for Latent Fingerprint Development on Unfired Cartridge Cases

Visualization of latent fingerprints on metallic surfaces by the method of applying electrostatic charging and adsorption is considered as a promising chemical‐free method, which has the merit of nondestruction, and is considered to be effective for some difficult situations such as aged fingerprint deposits or those exposed to environmental extremes. In fact, a portable electrostatic generator can be easily accessible in a local forensic technology laboratory, which is already widely used in the visualization of footwear impressions. In this study, a modified version of this electrostatic apparatus is proposed for latent fingerprint development and has shown great potential in visualizing fingerprints on metallic surfaces such as cartridge cases. Results indicate that this experimental arrangement can successfully develop aged latent fingerprints on metal surfaces, and we demonstrate its effectiveness compared with existing conventional fingerprint recovery methods.     

Visualization of Latent Fingerprint Corrosion on a Discharged Brass Shell Casing

Abstract:  Latent fingerprint visualization on discharged shell casings can provide good forensic evidence, particularly if the casing is recovered at the scene of a crime where a firearm has been discharged. Unfortunately, visualization of such latent fingerprints when they were deposited prior to discharge of the firearm is problematic as both increased temperature and abrasive friction can inhibit fingerprint visualization with conventional techniques. We present a case study that demonstrates latent fingerprint visualization on a discharged shell casing recovered 14 years ago from the scene of a homicide. Previous cyanoacrylate fuming of the casing had failed to reveal any fingerprints. We use a visualization technique in which a conducting carbon powder adheres preferentially to latent fingerprint corrosion of the casing surface, following the application of a potential of 2.5 kV to the casing. This technique presents opportunities for the review of old cases and for consideration of its use in current cases.     

Visualization of Latent Fingerprint Corrosion of Brass

Abstract:  Visualization of latent fingerprint deposits on metals by enhancing the fingerprint-induced corrosion is now an established technique. However, the corrosion mechanism itself is less well understood. Here, we describe the apparatus constructed to measure the spatial variation (Δ V ) in applied potential ( V ) over the surface of brass disks corroded by latent fingerprint deposits. Measurement of Δ V for potential of 1400 V has enabled visualization of fingerprint ridges and characteristics in terms of this potential difference with Δ V typically of a few volts. This visualization is consistent with the formation of a Schottky barrier at the brass-corrosion product junction. Measurement of the work function of the corroded brass of up to 4.87 ± 0.03 eV supports previous results that suggested that the corrosion product is composed of p-type copper oxides. A model for the galvanic corrosion of brass by ionic salts present in fingerprint deposits is proposed that is consistent with these experimental results.