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.     

Handguns and ammunitions indicators extracted from the GSR analysis

The computer automated scanning electron microscope. X-ray microanalysis of Firearms Discharge Residue (FDR) can reveal substantial information about the circumstances of their generation beyond the presence of characteristic gunshot residue (GSR). Indicators of the type of weapon and ammunition used can he obtained from the distribution of GSR particle shapes and from the multi-element analysis of the FDR sample. This is demonstrated for a large database of GSR samples from nine different handguns and over 60 different ammunitions. An example classification scheme is presented for the supporting particles generally found present in FDR. When particle type area concentration ratios are normalized to the iron (Fe) particle type, results show it is possible to distinguish much about the metal used in the weapon manufacture, whether it was of large or small caliber, whether the bullets were jacketed or plated, and whether the cartridge cases were of aluminum, brass, or nickel-plated brass. Standardization of such analytical schemes would be advantageous.     

Building a post-war justice system in Afghanistan

This paper examines key dimensions of justice in post–war Afghanistan. These areshari'a(Islamic law), traditional institutions of informal justice (jirga), the Afghan interim legal framework, and human rights principles. It is argued that despite their apparent incompatibility, these various dimensions of justice could be integrated within a coherent framework of a new justice system in post–war Afghanistan –– a framework that would promote interaction between local institutions of informal justice and a district level court of justice, on the one hand, and between these two and a proposed human rights unit, on the other. On the basis of this analysis, an experimental model of a system of justice is proposed, which integrates local jirga and human rights units into the existing formal justice (based on shari'a and positive law) and law–enforcement institutions. This experimental model provides a multi–dimensional framework that both reflects the cultural and religious values of Afghan society, and at the same time, has the capacity to draw on human rights principles. It is maintained that the model has the capacity to deliver justice expeditiously and in cost–effective ways; it also has a strong potential to act as a channel of communication between ordinary people and a modern participatory state in post–war Afghanistan. However, in order to test the applicability of this model in the real world, it needs first to be thoroughly discussed among Afghan and international legal experts as well as among ordinary Afghan people, and then piloted in selected districts in Afghanistan.     

A Comparison of Cleaning Regimes for the Effective Removal of Fingerprint Deposits from Brass

Abstract:  Effective removal of fingerprint deposits is crucial for experimentation related to the corrosion of metals by fingerprint deposits. Such removal is also necessary prior to deposition of test fingerprints. The effectiveness of four regimes in removing fingerprint deposits from brass is considered. Sustained wiping of the deposit with a tissue at applied pressures of up to c . 1430 Pa or rubbing while the brass was immersed in acetone both failed to remove completely all traces of fingerprint deposits. Heating the brass to 600°C was an effective remover; however, this also oxidized the surface of the metal except where inhibited by fingerprint deposits. The most effective regime, and the only one of the four that removed all traces of deposit without affecting the properties of the metal surface, was immersion in warm soapy water while rubbing with a tissue. We propose this as the preferred method for fingerprint removal.     

Optical enhancement of fingerprint deposits on brass using digital color mapping

Abstract: The reflection of visible light from α‐phase brass subject to surface oxidation in air at elevated temperatures is investigated. X‐ray photoelectron and auger electron spectroscopy confirm that covered areas of brass (not exposed to air) display dezincification but an absence of significant surface oxidation, confirming a differential oxidation mechanism. Visualization of differential oxidation is shown to be enhanced by selective digital mapping of colors reflected from the surface of the brass using Adobe^® Photoshop^®. Enhancement is optimal when the brass is heated to ～250°C with areas of oxidation having a mirror‐like appearance. The use of this enhancement method to produce a faithful image of fingerprint ridge characteristics is demonstrated on brass shell casings where fingerprints were deposited prefiring.     

The Effect of Light Exposure on the Degradation of Latent Fingerprints on Brass Surfaces: The Use of Silver Electroless Deposition as a Visualization Technique

We have studied the degradation of sebaceous fingerprints on brass surfaces using silver electroless deposition (SED) as a visualization technique. We have stored fingerprints on brass squares either (i) in a locked dark cupboard or (ii) in glass‐filtered natural daylight for periods of 3 h, 24 h, 1 week, 3 weeks, and 6 weeks. We find that fingerprints on brass surfaces degrade much more rapidly when kept in the light than they do under dark conditions with a much higher proportion of high‐quality prints found after 3 or 6 weeks of aging when stored in the dark. This process is more marked than for similar fingerprints on black PVC surfaces. Identifiable prints can be achieved on brass surfaces using both SED and cyanoacrylate fuming (CFM). SED is quick and straightforward to perform. CFM is more time‐consuming but is versatile and can be applied to a wider range of metal surfaces than SED, for example brass surfaces which have been coated by a lacquer.     

The Legal Status of Afghan Refugees in Pakistan, a Story of Eight Agreements and Two Suppressed Premises

Over 25 per cent of present day refugees enjoy asylum in Pakistan,most of them having been there for more than a quarter of acentury. Pakistan is not, however, a party to either the 1951Convention relating to the Status of Refugees or the 1967 Protocolrelating to the Status of Refugees. The legal status of theAfghan refugees it hosts is therefore not a foregone conclusion,even though they were considered to be refugees on a prima faciebasis during the first two decades of their exile in Pakistan.This article identifies the legal status of the Afghan refugeeson the basis of a series of agreements Pakistan concluded withUNHCR and also occasionally with Afghanistan. By virtue of thelast of the series of agreements, Afghan refugees can returnto Afghanistan under a UNHCR-assisted voluntary repatriationprogramme until December 2009. In view of the fact that allAfghans have been granted leave to stay in Pakistan until thesame date, many are expected to stay in Pakistan rather thanreturn with the assistance of UNHCR. Unlike the preceding agreements,the last one does not address the fate of those who will stillbe in Pakistan upon completion of the voluntary repatriationprogramme. It seems therefore imperative to identify the legalstatus and corresponding entitlements of the Afghan refugees.It is argued that the prima facie recognition of refugee statuscan be sustained on the basis of the agreements referred to.In addition it is argued that the current ‘profiling’exercise of UNHCR, even while presumably beneficial for themost vulnerable refugees, is irreconcilable with the statusand entitlements of the Afghan refugees, and the same holdstrue with respect to the usual practice of ‘screening’those refugees who have opted not to return under a voluntaryrepatriation programme. An alternative that would be reconcilableis a collective cessation of refugee status if and when thesituation in the country of origin so warrants, provided individualrefugees may contest this.     

A Collaboration,Not a Duel

In a number of articles published in LG, advocates take on the appearance, in readers' eyes, of lone fighters for truth, law, and justice in the courts. There is no other party on whom a defendant can depend for defense of his legal rights. The picture that emerges is that of the defense counsel as an "adversary" in the case, conducting a struggle over the defendant with another "adversary," the procurator, the state prosecutor. In such a situation, the latter naturally seeks to incriminate, to bring about punishment of the defendant. And for him this is, after all, easy, for behind him is the entire powerful system of the procuracy with all its organizational and technical resources!     

Assuring space shuttle orbiter subcontractor compliance with the NASA new technology clause

NASA's Charter demands that innovations arising from the agency's work receive the widest possible dissemination to bring about a transfer of the technology to the public welfare. This Spinoff from the Space Program is now a predictable event because of analyses done over the years by NASA and economists. However, the initial identification of innovations must be done through disclosures from NASA, prime contractor and subtier contractor employee innovators. Although NASA provides innovators with nominal cash awards for published innovations and inventions, a problem exists for NASA in assuring that all valuable innovations and inventions get promptly identified, reported and disseminated. This paper describes the technique developed by NASA's prime contractor for Shuttle Orbiter (Rockwell Space Division), which has successfully captured over 1200 innovations for NASA-JSC. Aspects of the Program described include the contract requirements, motivational techniques, results, problems, and a discussion of the results. An order of magnitude increase in innovation reporting resulted from Rockwell's activities primarily accomplished using an inexpensive four-step process implemented at about 200 subcontractor's facilities.     

Columnar‐Thin‐Film‐Assisted Visualization of Depleted Sebaceous Fingermarks on Nonporous Metals and Hard Plastics

A fingermark on a nonporous substrate can be developed by depositing a columnar thin film (CTF) on it, but the CTF technique's sensitivity for low‐quality fingermarks is unknown. The optimized CTF and traditional development of several depletion series of sebaceous‐loaded fingermarks were compared using a split‐print methodology as well as subjective and objective grading schemes, in a limited laboratory trial. CTF development was superior to development with selected traditional techniques on brass, anodized aluminum, black acrylonitrile butadiene styrene (ABS), and white nylon. On white ABS and black nylon, the CTF technique performed poorly but still as well as the best‐performing traditional development technique. The CTF technique was more sensitive on brass and anodized aluminum than, and as sensitive on the four hard plastics and stainless steel as, the best‐performing traditional technique. Thus, the CTF technique is useful to develop friction‐ridge detail from limited fingermark residue on some smooth substrates.     

Afghan Questions

The international community views the national reconciliation process in Afghanistan as a bold political experiment that can have a most beneficial impact on the elimination of regional conflicts throughout the world. It is not by chance that this innovative initiative is already being supported and continued by the revolutionary government of Nicaragua, along whose borders an undeclared war has been waged for many years now by the "Contras" financed by the United States. As M. S. Gorbachev, General Secretary of the CPSU Central Committee, stated in his Declaration on Afghanistan, "this is an expression of new political thought on the Afghan side." This is also an opportunity to demonstrate our good will to the great powers whose governments and peoples bear special responsibility for the elimination and prevention of dangerous hotbeds of tension on earth.     

The effect of electrostatic fingerprint visualization on integrated ballistic identification systems

Visualization of fingerprint corrosion on spent brass cartridge cases by the application of a high electrical potential and conducting carbon powder is becoming an accepted method of fingerprint enhancement. However, to date, no examination has been made of any effect this technique has on ballistic identification. To resolve this, images of the breech face and firing pin marks were captured on six plated nickel and six brass primer cup spent cartridge cases. Three nickel and three brass cases were then subjected to the application of a potential of +2500 V for a period of 1 min. The remaining cases were additionally subjected to the application of carbon powder. These latter cases were then washed to remove all traces of powder. Each case was recaptured with the same ballistic identification apparatus and imaging procedure. None of the twelve cases showed any visual difference after the application of the potential or conducting powder.     

Effect of Temperature on the Visualization by Digital Color Mapping of Latent Fingerprint Deposits on Metal

Visualization of fingerprint deposits by digital color mapping of light reflected from the surface of heated brass, copper, aluminum, and tin has been investigated using Adobe^® Photoshop^®. Metals were heated to a range of temperatures (T) between 50°C and 500°C in 50°C intervals with enhancement being optimal when the metals are heated to 250°C, 350°C, 50°C, and 300°C, respectively, and the hue values adjusted to 247°, 245°, 5°, and 34°, respectively. Fingerprint visualization after color mapping was not degraded by subsequent washing of the metals and color mapping did not compromise the visibility of the fingerprint for all values of T. The optimum value of T for fingerprint visibility is significantly dependent of the standard reduction potential of the metal with Kendall's Tau (τ) = 0.953 (p < 0.001). For brass, this correlation is obtained when considering the standard reduction potential of zinc rather than copper.     

Effect that the relative abundance of copper oxide and zinc oxide corrosion has on the visualization of fingerprints formed from fingerprint sweat corrosion of brass

From an examination of the fingerprint sweat corrosion of 40 different individuals on α phase brass, we show that an increase in visualization can be achieved by applying a negative potential to the brass followed by the introduction of a conducting powder. Previously, this technique has been demonstrated only for a positive applied potential and a corrosion product that was dominated by p-type copper (I) oxide. X-ray photoelectron and Auger electron spectroscopic analyses of the surface of the corroded brass show that an increase in visualization with a negative applied potential corresponds with an increase in the concentration of n-type zinc oxide relative to p-type copper (I) oxide with the Cu:Zn ratio <0.8:1. Work function conditions for the formation of an n-type zinc oxide/brass rectifying Schottky barrier are fulfilled.     

A Comparison of Fingerprint Sweat Corrosion of Different Alloys of Brass

Fingerprint sweat from 40 donors was deposited onto samples of five α and α + β phase brasses, comprising five alloys with different copper and zinc concentrations, two of which also had the addition of small concentrations of lead. Visual grading of the visibility of the corrosion revealed that brasses with the least amount of zinc produced the most visible and fully formed fingerprints from the most donors. Consideration of previously reported mechanisms for the corrosion of brass suggests red copper (I) oxide as a likely corrosion product for low zinc brasses, and a consideration of the color, composition, and solubility of fingerprint sweat corrosion products suggests that copper (I) oxide produces good contrast and visibility with the brass substrate. Scanning electron microscope images of the corrosion of all five alloys confirmed the enhanced contrast between corroded and uncorroded areas for low zinc alloys.     

Dutch Courts' Universal Jurisdiction over Violations of Common Article 3 qua War Crimes

On 14 October 2005, The Hague District Court sentenced two Afghanasylum seekers for their role and participation in the tortureof civilians during the Afghan War of 1978–1992. The Courtheld in both cases that it had ‘universal jurisdiction’over violations of Common Article 3 of the Geneva Conventionsand that the accused were guilty of ‘torment’ (‘foltering’)and torture as a war crime (‘marteling’). The jurisdictionalbasis relied upon by the Court and the Court's legal reasoningin both cases is open to criticism.     

Sectarianization: Mapping the New Politics of the Middle East. Hashemi Nader and Danny Postel,eds. (Oxford and New York: Oxford University Press, 2017).

In 2014, the Middle East appeared to teeter on the brink of an all-out sectarian war between Sunnis and Shi’as. In June of that year, the major Iraqi city of Mosul fell to the Islamic State of Iraq and Syria in a matter of days, bringing the group closer to its vow to eliminate all Shi’as and other religious minorities living in its self-proclaimed Islamic caliphate. Several hundred miles to the west, Iran’s Revolutionary Guard Corps were actively training Afghan Shi’a fighters to support the demoralized troops of Bashar Assad.     

Visualization of latent fingermark corrosion of brass, climatic influence in a comparison between the U.K. and Iraq

Through a comparison of fingermark sweat corrosion of α phase brass in both the U.K. and Iraq, we show how samples from Iraq have improved fingermark corrosion over U.K. samples that require no additional enhancement prior to visualization. Over 50% of Iraqi samples produced fingermark corrosion with full ridge detail compared with 0% from the U.K. X-ray photoelectron spectroscopy analysis of the fingermark corrosion products showed that Iraqi samples exhibit more dezincification with the Zn:Cu ratio averaging 1:1.82 compared with 1:3.07 for U.K. samples. Auger spectroscopy showed the presence of both zinc oxide and copper (I) oxide. No copper (II) was observed on the surface of the corroded brass. Opportunities to exploit the optical properties of these thin film oxides to enhance the visualization of fingermark corrosion are considered, and the potential to use fingermark corrosion of metal as a means of visualizing fingerprints in war zones is discussed.     

Provenance and Price: Autoregulation of the Antiquities Market?

It is becoming common to read that antiquities without a provenance stretching back to before the 1970 adoption by UNESCO of the Convention on the Means of Prohibiting and Preventing the Illicit Import, Export and Transfer of Ownership of Cultural Property are increasingly difficult to sell because of customer concerns over possible illicit trade in the past and reduced resale prices in the future. This paper proposes the term autoregulation to describe the phenomenon, and presents the results of several quantitative analyses designed to investigate its action.