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Revealing obliterated engraved marks on high strength aluminium alloy (AA7010) surfaces by etching technique

Bong YU, Kuppuswamy R

Forensic Sci Int, 2010 Feb 25;195(1-3):86-92.
PMID: 20022189 DOI: 10.1016/j.forsciint.2009.11.018

Restoration of obliterated engraved marks on high strength Al-Zn-Mg-Cu alloy (AA7010) surfaces by etching technique was studied. The alloy surfaces were mechanically engraved with some identification marks using "Gravograph". The marks were then erased by removing the metal to different levels up to and below the depth of engraving. Five metallographic reagents were tested on the obliterated surfaces by etching. The following two methods (i) immersion in 10% aq. phosphoric acid and (ii) alternate swabbing of 60% HCl and 40% NaOH were found to be quite effective to reveal the obliterated marks. These two procedures were also able to show effectively the marks obliterated by over-engraving and centre punching. Of the two techniques immersion in phosphoric acid provided more contrast. Interestingly, alternate swabbing of 60% HCl and 40% NaOH presented itself to be the common reagent for restoration on pure aluminium as well as its alloy surfaces. This is evident from our own current experiments and those of earlier researchers [G. Peeler, S. Gutowski, H. Wrobel, G. Dower, The restoration of impressed characters on aluminium alloy motor cycle frames, J. Forensic Ident. 58 (1) (2008) 27-32; M. Izhar M. Baharum, R. Kuppuswamy, A.A. Rahman, Restoration of engraved marks on aluminium surfaces by etching technique, Forensic Sci. Int. 177 (2008) 221-227]. The findings have assumed importance as engines and chassis of cars and frames of firearms are currently made of high strength aluminium alloys and recovery on these surfaces by current methods is not satisfactory.

Matched MeSH terms: Firearms
Optimization of headspace solid-phase microextraction technique for extraction of volatile smokeless powder compounds in forensic applications

Chang KH, Yew CH, Abdullah AF

J Forensic Sci, 2014 Jul;59(4):1100-8.
PMID: 24611488 DOI: 10.1111/1556-4029.12440

Smokeless powders are low explosives and are potentially found in cases involving firearms and improvised explosive devices. Apart from inorganic compound analysis, forensic determination of organic components of these materials appears as a promising alternative, especially the chromatographic techniques. This work describes the optimization of a solid-phase microextraction technique using an 85 μm polyacrylate fiber followed by gas chromatography-flame ionization detection for smokeless powder. A multivariate experimental design was performed to optimize extraction-influencing parameters. A 2(4) factorial first-order design revealed that sample temperature and extraction time were the major influencing parameters. Doehlert matrix design has subsequently selected 66°C and 21 min as the compromised conditions for the two predetermined parameters. This extraction technique has successfully detected the headspace compounds of smokeless powders from different ammunition types and allowed for their differentiation. The novel technique allows more rapid sample preparation for chromatographic detection of smokeless powders.

Matched MeSH terms: Firearms
Fulltext Retained intraspinal bullet: a rare case in a visitor to malaysia - a case report

Ariffin M, Noreen F, Nor Hamdan Y, Shaharuddin AR, Azmi B

Malays Orthop J, 2012 Nov;6(3):45-7.
PMID: 25279057 MyJurnal DOI: 10.5704/MOJ.1207.005

Firearm injuries to the spine commonly present with acute neurology caused by direct penetration or indirectly from concussive effects of bullet impact on the vertebral column. We report a case of delayed neurologic presentation of retained intra-spinal bullet in a 42 year-old African who had chronic low back pain and sciatica with a past history of gunshot injury to the spine and radiograph revealed a bullet at the L4-5 disc level. Intra-operative exploration showed a fibrous mass around the bullet compressing on the L4 existing nerve root and L5 traversing nerve root. Removal of the retained bullet resulted in a good clinical outcome with complete resolution of symptoms.

Matched MeSH terms: Firearms
Analysis of geometric moments as features for firearm identification

Md Ghani NA, Liong CY, Jemain AA

Forensic Sci Int, 2010 May 20;198(1-3):143-9.
PMID: 20211535 DOI: 10.1016/j.forsciint.2010.02.011

The task of identifying firearms from forensic ballistics specimens is exacting in crime investigation since the last two decades. Every firearm, regardless of its size, make and model, has its own unique 'fingerprint'. These fingerprints transfer when a firearm is fired to the fired bullet and cartridge case. The components that are involved in producing these unique characteristics are the firing chamber, breech face, firing pin, ejector, extractor and the rifling of the barrel. These unique characteristics are the critical features in identifying firearms. It allows investigators to decide on which particular firearm that has fired the bullet. Traditionally the comparison of ballistic evidence has been a tedious and time-consuming process requiring highly skilled examiners. Therefore, the main objective of this study is the extraction and identification of suitable features from firing pin impression of cartridge case images for firearm recognition. Some previous studies have shown that firing pin impression of cartridge case is one of the most important characteristics used for identifying an individual firearm. In this study, data are gathered using 747 cartridge case images captured from five different pistols of type 9mm Parabellum Vektor SP1, made in South Africa. All the images of the cartridge cases are then segmented into three regions, forming three different set of images, i.e. firing pin impression image, centre of firing pin impression image and ring of firing pin impression image. Then geometric moments up to the sixth order were generated from each part of the images to form a set of numerical features. These 48 features were found to be significantly different using the MANOVA test. This high dimension of features is then reduced into only 11 significant features using correlation analysis. Classification results using cross-validation under discriminant analysis show that 96.7% of the images were classified correctly. These results demonstrate the value of geometric moments technique for producing a set of numerical features, based on which the identification of firearms are made.

Matched MeSH terms: Firearms
Development of an objective method for the comparison of fired projectiles using an air pistol as a template

Hamzah NH

Forensic Sci Int, 2016 07;264:106-12.
PMID: 27081766 DOI: 10.1016/j.forsciint.2016.03.050

The ability to objectify ballistic evidence is a challenge faced by firearms examiners around the world. A number of researchers are trying to improve bullet-identification systems to address deficiencies detailed within the National Academy of Science report (2009). More recently focus has turned to making use of more sophisticated imaging modalities to view entire regions of the projectile and the development of automated systems for the comparison of the topographical surfaces recorded. Projectiles from a newly bought air pistol with 0.177 calibre pellets (unjacketed), fired series of 609 pellets were examined using an optical microscope. A mathematical methodology was developed to pre-process the resultant topographical maps generating point data for comparison, analysed using the principal component analysis (PCA). In most cases limited to reasonable success was achieved. The objective method still requires an operator to identify the Land Engraved Areas to be scanned, however the mathematical alignments were objectively achieved. The PCA results illustrated that the striation marks were neither exclusive nor specific to the LEA regions but rather crossed over regions. This study also proves that a single weapon does not necessarily leave identical marks of projectiles on its surface.

Matched MeSH terms: Firearms
Fulltext Development of a green combat armour from Rame-Kevlar-polyester composite

Zainab Shakir Radif, Aidy Ali, Khalina Abdan

Pertanika Journal of Science & Technology, 2011;19(2):339-348.
MyJurnal

This study was conducted for the development of the green protection garments. For this purpose, laminate composite material was developed from Kevlar 29-ramie-unsaturated polyester resin. The aim of this study was to develop a solid body armour that meets the specific requirements of ballistic resistance. This composite is subjected to high impact loading. The target was shot using gas gun machine that is supported by camera hardware to capture the projectile speed. In order to achieve the goal of the research, several experiments were conducted with the aim to estimate the ballistic limit, maximum energy absorption, composite failure mode, life time rupture, target geometry, and environmental effect. The results of these experiments indicated that the maximum ballistic limit validated at impact speed is in the range of 250 m/s to 656.8 m/s for the second protection level. The targets are improved in term of the impact response with the increase in the relative humidity, i.e. the range of 50% ± 20%, whereas, reduction of resistance results in the increase of temperature. The range of temperatures was between 20oC and 70oC. A limited delamination was generated under multiple shots. Targets geometry plays a major role in increasing the impact response. Hence, the results present a high resistant impact for pairs from the panels with total thickness arrived to 15
mm ± 3 mm. This body armour is one of the most economical armour products, in which common materials are used in its production, particularly to reduce the amount of Kevlar, and this could further lead to a decrease in its production cost. On the other hand, this armour meets the ballistic threats under 623 m/s of 15 mm ± 3 mm target thickness and 837.5 m/s of 25 mm ± 2.mm. Thus, the armour is equivalent to the third level of protective ballistic limits in the National Institute of Justice (NIJ) standards.

Matched MeSH terms: Firearms
Restoration of engraved marks on steel surfaces by etching technique

Zaili MA, Kuppuswamy R, Harun H

Forensic Sci Int, 2007 Aug 24;171(1):27-32.
PMID: 17088038

It is known that restoration of erased engraved identification marks on the engine and the chassis of a car or on a firearm has low success rate. Unlike stamping, engraving on a metal surface leaves no pronounced, permanent subsurface deformation in the crystalline structure, also called dislocation that can be revealed by suitable methods. Hence, the current research work investigated whether metallographic reagents used in the restoration of stamp (compression) marks could be applied to recover engraved marks on steel surfaces and also to establish the sensitivity and effectiveness of some of these reagents for the restoration of the marks. Experiments were conducted by mechanically engraving alphanumeric characters on several steel plates using a computer controlled engraving machine called Gravograph. The markings were later erased from the above steel plates by removing the metal in stages of 0.01 mm through 0.04 mm below the bottom of the engraving. Several plates were thus prepared wherein each one had been abraded to a specific depth. Then eight metallographic reagents were tested on each one of the above erased plates using a swabbing technique. The results had shown that while most of the reagents were able to restore marks up to certain levels of erasure, the reagent 5 g copper sulphate, 60 ml water, 30 ml concentrated ammonium hydroxide and 60 ml concentrated hydrochloric acid restored marks erased to a depth of 0.04 mm below the engraving depth, thus presenting itself the most sensitive reagent. Quite significantly, the above reagent was also able to decipher successfully the original engraved marks that had been erased and engraved with a new number, or obliterated by centre punching. The results of this research work should benefit the forensic practitioners engaged in the serial number recovery on vehicles, firearms and other objects.

Matched MeSH terms: Firearms
Study of the Behaviors of Gunshot Residues from Spent Cartridges by Headspace Solid-Phase Microextraction-Gas Chromatographic Techniques

Chang KH, Yew CH, Abdullah AF

J Forensic Sci, 2015 Jul;60(4):869-77.
PMID: 25771708 DOI: 10.1111/1556-4029.12745

Gunshot residues, produced after shooting activity, have acquired their importance in analysis due to the notoriety of firearms-related crimes. In this study, solid-phase microextraction was performed to extract the headspace composition of spent cartridges using 85-μm polyacrylate fiber at 66°C for 21 min. Organic compounds, that is, naphthalene, 2,6-dinitrotoluene, 2,4-dinitrotoluene, diphenylamine, and dibutyl phthalate were detected and analyzed by gas chromatography-flame ionization detection technique. Evaluation of chromatograms for diphenylamine, dibutyl phthalate, and naphthalene indicates the period after a gunshot was discharged, whether it was 1 days, 2-4 days, <5 days, 10 days, 20 days, or more than 30 days ago. This study revealed the potential effects of environmental factors such as occasional wind blow and direct sunlight on the estimation of time after spent cartridges were discharged. In conclusion, we proposed reliable alternative in analyzing the headspace composition of spent cartridges in a simulated crime scene.

Matched MeSH terms: Firearms
Fulltext Intralenticular matchstick in a toddler: a rare presentation of penetrating ocular injury from a toy gun

Royan, Jeyarine, Teo, Khairy Shamel Sonny, Vengadasalam, Selva Raja

Journal of Biomedical and Clinical Sciences, 2018;3(1):15-18.
MyJurnal

To report on a rare case of an intralenticular foreign body which
demonstrates that use of a spring-powered airsoft gun can result in a severe
ocular injury. A 2-year-old male presented following a trauma to the left eye.
The trauma was caused by a wooden matchstick from a spring-powered airsoft
gun being shot into his eye. On examination, there was a shallow anterior
chamber with a full thickness corneal laceration, with fragmented matchstick
pieces embedded in the cornea and in the lens. The corneal foreign bodies
were removed, corneal laceration wound sutured and lensectomy done. There
were no post-operative complications, and the cornea wound healed with a
scar. A few months later, he underwent a successful secondary intraocular lens
implantation surgery with an iris claw lens. Airsoft guns are easily available to
children who are unaware of its dangers. It can cause significant ocular
morbidity despite successful surgical treatment of the injury.

Matched MeSH terms: Firearms
Fulltext Global Mortality From Firearms, 1990-2016

Global Burden of Disease 2016 Injury Collaborators, Naghavi M, Marczak LB, Kutz M, Shackelford KA, Arora M, et al.

JAMA, 2018 Aug 28;320(8):792-814.
PMID: 30167700 DOI: 10.1001/jama.2018.10060

IMPORTANCE: Understanding global variation in firearm mortality rates could guide prevention policies and interventions.
OBJECTIVE: To estimate mortality due to firearm injury deaths from 1990 to 2016 in 195 countries and territories.
DESIGN, SETTING, AND PARTICIPANTS: This study used deidentified aggregated data including 13 812 location-years of vital registration data to generate estimates of levels and rates of death by age-sex-year-location. The proportion of suicides in which a firearm was the lethal means was combined with an estimate of per capita gun ownership in a revised proxy measure used to evaluate the relationship between availability or access to firearms and firearm injury deaths.
EXPOSURES: Firearm ownership and access.
MAIN OUTCOMES AND MEASURES: Cause-specific deaths by age, sex, location, and year.
RESULTS: Worldwide, it was estimated that 251 000 (95% uncertainty interval [UI], 195 000-276 000) people died from firearm injuries in 2016, with 6 countries (Brazil, United States, Mexico, Colombia, Venezuela, and Guatemala) accounting for 50.5% (95% UI, 42.2%-54.8%) of those deaths. In 1990, there were an estimated 209 000 (95% UI, 172 000 to 235 000) deaths from firearm injuries. Globally, the majority of firearm injury deaths in 2016 were homicides (64.0% [95% UI, 54.2%-68.0%]; absolute value, 161 000 deaths [95% UI, 107 000-182 000]); additionally, 27% were firearm suicide deaths (67 500 [95% UI, 55 400-84 100]) and 9% were unintentional firearm deaths (23 000 [95% UI, 18 200-24 800]). From 1990 to 2016, there was no significant decrease in the estimated global age-standardized firearm homicide rate (-0.2% [95% UI, -0.8% to 0.2%]). Firearm suicide rates decreased globally at an annualized rate of 1.6% (95% UI, 1.1-2.0), but in 124 of 195 countries and territories included in this study, these levels were either constant or significant increases were estimated. There was an annualized decrease of 0.9% (95% UI, 0.5%-1.3%) in the global rate of age-standardized firearm deaths from 1990 to 2016. Aggregate firearm injury deaths in 2016 were highest among persons aged 20 to 24 years (for men, an estimated 34 700 deaths [95% UI, 24 900-39 700] and for women, an estimated 3580 deaths [95% UI, 2810-4210]). Estimates of the number of firearms by country were associated with higher rates of firearm suicide (P

Matched MeSH terms: Firearms/statistics & numerical data*
Fulltext Posterior intraorbital metallic foreign body: a case discussion

Vinodh VP, Sellamuthu P, Harun RH, Zenian MS

Med J Malaysia, 2014 Apr;69(2):89-91.
PMID: 25241819 MyJurnal

Intraorbital foreign body (IOFB) has been a rare phenomenon in the cases of gunshot wounds and always represents a dilemma in medical management. In Sabah, this scenario is becoming common as there is still certain population in the interiors who owns self made guns for hunting. They either present with self inflicted gunshot injuries or after being mistakenly shot while hunting. There are very few articles on this topic especially when it is located posteriorly in the orbit and occurs without visual impairment. This case reports the challenges faced in the management of the patient with a posteriorly located metallic IOFB. The appropriate management of the patient is discussed based on several international literatures. Author describes a 37 years old male farmer, who was referred from a nearby district hospital after he sustained gunshot injuries to his face and scalp. Urgent computed tomography (CT) scan showed that bullet pellets were at the left orbital floor, the left mandible and the left frontal bone. All bullet pellets were located extracranially only without intracranial involvement. Patient clinically does not have any neurologic deficit and without any visual impairment, thus he refused any surgical intervention. As there is no proper guideline in managing such cases, decision was made based on evidences from international literatures. It was concluded that metallic IOFB located in the posterior orbit may be conservatively managed with observation and regular follow-ups as they are well-tolerated and does not cause much impact on visual deterioration unless inflammation, infection, optic neuropathy or functional deficit occurs. This avoids unnecessary surgery and prevents risk of iatrogenic injury to the eye.

Matched MeSH terms: Firearms
[Stability of the "amok runner syndrome"]

Adler L, Marx D, Apel H, Wolfersdorf M, Hajak G

Fortschr Neurol Psychiatr, 2006 Oct;74(10):582-90.
PMID: 16586259

Running amok is considered a rare but dangerous act of violence which has been investigated predominantly on a case by case basis. German-wide data on amok cases covering the decades 1980 - 1989 and 1991 - 2000 were used to perform the first epidemiological study world-wide on the stability of socio-demographic, criminological and psychiatric variables of amok behaviour.

Matched MeSH terms: Firearms

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