Metal objects mapping after small charge explosions. A study on AISI 304Cu steel with two different grain sizes

Evidence of exposure of a metal component to a small charge explosion can be detected by observing microstructural modifications; they may be present even if the piece does not show noticeable overall plastic deformations. Particularly, if an austenitic stainless steel (or another metal having a face-centered cubic structure and a low stacking fault energy) is exposed to an explosive shock wave, high-speed deformation induces primarily mechanical twinning, whereas, in nonexplosive events, a lower velocity plastic deformation first induces slip. The occurrence of mechanical twins can be detected even if the surface is damaged or oxidized in successive events. In the present research, optical metallography (OM) and scanning electron microscopy (SEM), and scanning tunneling microscopy (STM) were used to detect microstructural modifications caused on AISI 304Cu steel disks by small-charge explosions. Spherical charges of 54.5 or 109 g TNT equivalent mass were used at explosive-to-target distances from 6.5 to 81.5 cm, achieving peak pressures from 160 to 0.5 MPa. Explosions induced limited or no macro-deformation. Two alloy grain sizes were tested. Surface OM and SEM evidenced partial surface melting, zones with recrystallization phenomena, and intense mechanical twinning, which was also detected by STM and X-ray diffraction. In the samples' interior, only twins were seen, up to some distance from the explosion impinged surface and again, at the shortest charge-to-sample distances, in a thin layer around the reflecting surface. For forensic science locating purposes after explosions, the maximum charge-to-target distance at which the phenomena disappear was singled out for each charge or grain size and related to the critical resolved shear stress for twinning.     

Citizenship at Europe's Borders: Some Reflections on the Post-colonial Condition of Europe in the Context of EU Enlargement

This article proposes a critical approach to European citizenship through the analysis of the legal dispositives which define the external borders of Europe in the context of EU enlargement. It examines the deterritorialization of the EU's external and internal borders through an analysis of the immigration laws of Poland, Romania and Bulgaria which have all been recently modified in order to meet the requirements of the Schengen aquis. By comparing these legislative changes with the legal mechanisms of colonial systems, the article suggests that the material process of the constitutionalization of EU citizenship highlights a post-colonial condition of the European polity.     

Multi-Rater Agreement Using the Adapted Fracture Healing Scale (AFHS) for the Assessment of Tubular Bones on Conventional Radiographs: Preliminary Study*

Better understanding of the timing of fracture healing may help in cases of interpersonal violence but also of personal identification. The intra- and inter-rater agreement for the adapted fracture healing scale (AFHS) assessing the post-traumatic time interval on radiographs were tested. This is a preliminary study, providing essential information on method reliability for upcoming studies using the AFHS. Five raters (two radiologists, a forensic pathologist, an orthopedist, and an anthropologist) were presented with a test in three parts consisting of 85 radiographs (from 30 adults) of fractures of tubular bones in different stages of healing purposefully selected from more than 1500 radiographs. The raters were firstly asked to assess 15 features describing fracture healing as present, absent, or not assessable. Thereafter, the raters were asked to choose from the AFHS a single-stage best representing the observed healing pattern. The intra- and inter-rater agreement were assessed using single-rating, absolute agreement, two-way mixed-effects intra-class correlation (ICC) coefficients. The intra-rater ICC of radiologist 1 ranged from 0.80 to 0.94. The radiologists’ inter-rater ICC ranged from 0.68 to 0.74, while it ranged from −0.01 to 0.90 for the other raters. The good to excellent ICC among the radiologists and forensic anthropologist provides good foundation for the use of the AFHS in forensic cases of trauma dating. The poor to good results for the other physicians indicate that using the AFHS requires training in skeletal anatomy and radiology.     

Development of a heptaplex PCR system to analyse X-chromosome STR loci from five Italian population samples. A collaborative study

Many X-chromosome short tandem repeats (X-STRs) have been validated for forensic use even if further studies are needed on allele frequencies and mutation rates to evaluate the extent of polymorphism in different populations and to establish reference databases useful for forensic applications and for anthropological studies. A single multiplex reaction of seven X-STRs, which includes the DXS6789, HUMARA, DXS10011, DXS7423, HPRTB, DXS6807, DXS101 loci, is presented and their allele frequency distribution in a large population sample including 556 subjects (268 females and 288 males) analysed by five forensic laboratories of Central and Northern Italy is shown. Our results demonstrate the feasibility of a single amplification/detection reaction involving seven markers of the X chromosome, which can be fruitfully used in complex kinship analysis.