Abstracts, Last Names A-L
Abstracts are listed alphabetically by the last name of the speaker. Abstracts and speakers are subject to change; check this page regularly for additions and updates.
Eight Is Enough: Fabric Physical Matches in an International Drug Smuggling Case
Jason C. Beckert — Microtrace LLC
Physical matches represent the highest level of associations that can be made using trace evidence. When a physical match is demonstrated, the examiner can conclude that two separate objects were once joined together as a single object. However, some substrates (e.g., fabric) can deform during the breaking process, and the significance of the conclusion is often reduced as a result.
This presentation will focus on a case study involving the physical matching of fabric straps to a bag containing drugs in a smuggling case. The condition of the evidence was a key factor and multiple fracture matches were observed in the slightly distorted fabric. While most of the individual fracture matches would be compelling enough on their own, the totality of the evidence clearly indicated that the objects were originally joined together.
Pigments in Olefin Fibers
Kelly Brinsko Beckert — Microtrace LLC
Due to their lack of binding sites, olefins such as polypropylene and polyethylene are difficult to dye after the fiber has been formed. Therefore, nearly all olefins are colored with pigments while the polymer is still molten prior to extrusion. Using pigments instead of dyes results in lightfast fibers, and this feature, together with other desirable properties such as stain and chemical resistance, give olefins application across many industries, including apparel, upholstery, carpeting, and building materials. These pigments are often difficult to see by light microscopy due to their small size, but there are several microscopical techniques which may be helpful, including phase contrast and polarized light. The pigments may also be analyzed using instrumental methods such as Raman microspectrometry, microspectrophotometry (MSP), or micro-FTIR.
Contributions of Polarized Light Microscopy and Microanalysis to a Recent Mail Bomb Case
Andrew M. Bowen — U.S. Postal Inspection Service
A recent explosives case involving two mail bombs that exploded when opened by customers demonstrates the value of polarized light microscopy (PLM) in explosives examinations. The combined use of PLM with Raman microspectroscopy, Fourier-transform infrared microspectroscopy, and energy-dispersive X-ray spectroscopy enabled a very small deposit of material on a match head to be examined and compared to matches recovered during the execution of search warrant at a suspect’s residence. The small quantity of available material necessitated a microscopical approach to its analysis. In addition, these same techniques were valuable in the analysis of a number of other materials submitted for examination in this case.
A Case Example Demonstrating the Value of Raman Microspectroscopy in Forensic Rope Examinations
Andrew M. Bowen — U.S. Postal Inspection Service
An outside agency case was submitted to the U.S. Postal Service Forensic Laboratory Services in 2017 requesting comparison of rope and sand samples to assist a major drug investigation. The results of the laboratory examination of these materials will be shared during this presentation. In particular, Raman microspectroscopy analysis was used to identify several pigments in two submitted ropes, and this information made the comparison of both rope samples considerably more probative. Polarized light microscopy was used for characterization and comparison of the submitted materials and to assist in the selection of pigment particles for Raman analysis.
Evaluation of the Criteria for the Discrimination of Inkjet Printer Inks Using Micro Raman Spectroscopy
Patrick Buzzini, Carrie Polston, Madison Schackmuth — Sam Houston State University
Inkjet printers are ubiquitous devices in our society. Therefore, it is not surprising that they are used to commit different types of illicit activities such as threats or extortions by means of anonymous letters, frauds in the context of disputed contracts, alterations to or counterfeit of ID documents, and counterfeit of currency banknotes. Inkjet printed documents produce microscopic colored dots that can be detected using a microscopical approach in conjunction with Raman spectroscopy. In the phase of this study, the criteria necessary to achieve discrimination between inkjet printer inks from different manufacturers, same manufacturers, and even same manufacturer models have been evaluated on a set of 11 samples. Although Raman spectroscopy is already a relatively well-established method for the characterization of colorants (both dyes and pigments), this study demonstrates that the contribution of minor peaks within Raman spectra improves the discriminating capabilities of the technique. The joint consideration of the three colored components was also effective in differentiating inkjet printer ink samples, especially those from the same manufacturer, and in some instances, from the same model as well.
The Effect of Ultraviolet Radiation on the Microspectrophotometry (MSP) of Dyed Fibers, Part 2: Spectral Differences as a Function of Time
Patrick Buzzini and Carrie Polston — Sam Houston State University
Meggan B. King — McCrone Research Institute
Single fibers from a collection of 53 textile samples were analyzed using UV-Vis microspectrophotometry (MSP), at eight week intervals, after being exposed to outdoor sunlight and placed into a laboratory UV radiation box. Differences between MSP spectra collected from fibers prior to exposure (T0) and after exposures of 8, 16, and 24 weeks (T8, T16, and T24, respectively) will be discussed. These samples span a variety of fiber types, dye types, and colors including 20 nylon, 14 polyester, eight acrylic, six viscose rayon, and five acetate fiber types dyed with a variety of colors (15 yellow, 14 red, 11 blue, four orange, four violet, three brown, one black, and one green) and dye-application types (29 disperse, six acid, 10 basic, five direct, two mordant, and one reactive). After a 24-week exposure, 15 samples out of the 53 did not exhibit changes in the shape and intensity of the collected spectra. However, 32 samples displayed spectral differences after exposure to sunlight or laboratory UV radiation. In 20 cases, spectral alterations were observed in the visible range only; changes in only the UV range were observed for two samples, while the remaining 10 samples displayed spectral differences in both the UV and the visible spectral ranges. The majority of samples (16) started showing spectral differences at T8, while seven samples showed spectral differences starting at T16. Finally, in six samples changes were observed only after T24. Observed types of alterations consisted of a decrease of band intensities, formation of new bands, or band shifts in wavelength values. Six samples displayed a large within-source variation, preventing the determination of whether spectral variations were due to alterations as a function of UV exposure. This research was funded by the National Institute of Justice (Award No. NIJ-2016-DN-0145).
Semi-Automated Micromorphometry of Small Arms Propellants for Brand Identification
Casey Brown, Jack Hietpas, and Wayne Moorehead — The Pennsylvania State University
According to a 2016 U.S. Bomb Data Center report, smokeless powders were one of the top explosive charges used in illicit detonation events. Smokeless powders are commonly used as the main charge in pipe bombs, the most common form of an improvised explosive device, likely due to their ease of procurement and unrestricted purchase. The focus of this study is to investigate the strengths and limitations of quantitative size and shape descriptors for smokeless powder sample differentiation and brand identification. Digital images of smokeless powder samples were captured using a macro camera and processed using open-source image analysis software. For each powder particle (n ≈ 34,000), eight shape and size parameters were measured. Using 80% of the data, linear discriminant analysis (LDA) was used to classify the 90 brands of smokeless powders. The remaining 20% of the data set was treated as unknowns and “matched” to the main data set samples using the shortest Mahalanobis distance. The algorithm correctly classified 83% of the unknown dataset. If the first two shortest distances are observed, the success rate increases to 97%. The results from this study are very encouraging but will require more samples to obtain a more robust assessment.
Elongate Mineral Particles: What Sizes Matter?
Eric J. Chatfield — Chatfield Technical Consulting Limited
The length distributions of single fibrils of Coalinga chrysotile, UICC-B chrysotile, and wet dispersed chrysotile were measured by transmission electron microscopy (TEM). It was found that the length distributions significantly diverged only above approximately 10 µm in length. These results correspond to differences in published results of animal experiments. This observation suggests that chrysotile fibrils shorter than approximately 10 µm are not correlated with the tumor incidences observed in prior animal experiments in which these sources of chrysotile were tested. This result is in contrast to published data in which counting of an insufficient number of fibers resulted in an erroneous conclusion that the length distribution of Coalinga chrysotile fibrils was indistinguishable from those of other sources of chrysotile.
The size distributions of the respirable particle size fractions from acknowledged tremolite asbestos samples were found to be dominated by elongate particles longer than 5 µm, which are within the dimensional range of non-asbestiform amphiboles. Prior studies have shown that these elongate particles obscure a correlation between a specific size range of particles and results of animal implantation studies using tremolite of various morphologies. In the prior studies, a reference protocol was developed from TEM measurements of particles from four crushed non-asbestiform amphiboles to differentiate the size range of amphibole particles that correlates with the mesothelioma frequencies observed in the animal studies. In the work reported here, this correlation was tested using TEM analyses of amphiboles from Libby, MT; Sparta, NJ; and Homestake Mine, Lead, SD, which represent known environmental/occupational situations.
Further TEM analyses of the tremolite samples used in the original animal implantation studies have shown that the numbers of elongate tremolite particles with lengths ≤ 5 µm implanted into the animals are not correlated with the observed mesothelioma frequencies. The results suggest that elongate tremolite particles with lengths ≤5 µm do not contribute to the carcinogenic response observed in the animal experiments.
Screenshot: Analysis of Bullet Hole Impact Dynamics
Peter Diaczuk and Xiao Shan Law — The Pennsylvania State University, Eberly College of Science, Forensic Science Program
This research project originated from a shooting case involving a suspected bullet hole through a window screen. After passing through the window screen, the bullet then passed through a plastic bottle on the window sill and continued until it encountered an occupant of the premises. When submitted for examination, the window screen contained two holes, so it became important to determine whether one or both holes found in the screen were made by one or more bullets, and could an angle be approximated (or excluded) based on the shape of the holes. The pre-existing gaps in aluminum window screens, which are formed by the warp and weft pattern of aluminum wire (similar to fabrics) were examined. Likewise, the damage to the bottle had to be assessed and evaluated. To determine differences in the entry and exit hole deformation, we fastened pieces of window screen material to wooden frames to simulate the frame of a typical window and fired upon them with different caliber bullets at different velocities and angles. High-speed photography was able to clarify the mechanism of bullet impact dynamics both through the screen and through the bottle on the window sill.
Aquatic Dinosaur Update II
Brian J. Ford — Cardiff University
What has happened since Brian J. Ford put the cells in a dinosaur’s tail under the lens for Inter/Micro on July 17, 2012, wrote in The Microscope, 60:3, pp 123-131 in 2012, and presented his talk “Aquatic Dinosaur Update” at Inter/Micro on July 16, 2013? His views attracted worldwide hostility from paleontologists, yet May 2018 saw the publication in London of his 400-page book on these new theories. Today, we will learn what has happened since. This is a saga of rivalry and double-dealing, of vitriol and bitter animosity — with lessons about the way modern science is being conducted.
Brian J. Ford — Cardiff University
Future medicine is being threatened by the widespread development of antibiotic resistance in bacteria. This is not new. When Alexander Fleming accepted the Nobel Prize in 1945 for his discovery of penicillin, he warned of the dangers posed by resistance of bacteria to antibiotics. There has been flagrant misuse of these potent antibacterials, (in agriculture for instance), but currently our problems are caused not by overuse, but by a failure to target therapy more effectively. Surprisingly, it is the underuse of antibiotics that poses the greatest problems.
Microscopy and Poetry: A Union of Art and Artifice
Andrew A. Havics — pH2, LLC
Microscopy allows one to peer into a visual world unseen by the naked eye, evoking thoughts and sometimes emotions; whereas poetry inspires one to create visions, emotions, and thought patterns using only words. The two worlds have been destined to intersect in both predictable and unexpected ways. The words alone have less meaning without first having viewed the microscopical images, and yet, the images evoke a desire to put words to paper. It is a marriage of art and artifice that often inspires microscopists to continue writing outside the lines of science. Thus, one begins an exploration of verse and rhyme: sonnets, odes, epigrams, limericks, poetry masquerading as quotes, and so on.
A Survey of Elements Detected in Multi-layered Automotive Paint Samples by SEM-EDS
Ethan Groves, Lina T. Michely, and Christopher S. Palenik — Microtrace, LLC
This talk presents the results of a survey of 300 automotive paints, comprised of over 1,200 layers, which have been characterized by energy-dispersive X-ray spectrometry (EDS) in a scanning electron microscope (SEM) to identify detectable elements and their frequency of occurrence as a function of layer type (clear coat, color coat, and primer). This seemingly trivial exercise is subject to numerous challenges, which illustrate the impact that data collection, data interpretation, and selection criteria can have on the ultimate list of detected elements. For example, selection criteria based upon auto-identification, a fixed element list, or evaluation by standardless quantification (e.g., >3 standard deviations, counting error) can lead to different results. Because this data is collected from “street” samples where the ground truth is not known, it is not possible to establish absolute selection criteria. However, despite this challenge, the resulting list provides a context for developing more formalized approaches to the interpretation of elemental analysis data for forensic paint comparisons.
Surface Samples for Indoor Environmental Quality: What Can They Tell Us?
Andrew A. Havics — pH2, LLC
Indoor environmental quality (IEQ) studies often include sampling surfaces. These may be tape-lift samples, bulk dust, micro-vacuum samples, RODAC plates, or settling plates. For mold cases, samples help evaluate presence, distribution, and growth or mold while the identification can help assist with conditions leading to their presence. For irritation and allergy concerns, the identification of particles can aid in narrowing or eliminating sources and origins. For soot particles, the identification and surface distribution can provide information on sources and the likelihood of them needing cleaning. Other particle types fill in gaps for understanding the environment, the inhabitants, the buildings they inhabit in addition to the particle sources and sinks.
Taking a Closer Look at Some Photochromic Materials
Joseph Insana — Microtrace, LLC
Photochromism is the phenomena by which a particular substance has a composition that allows it to transition or transform into a different chemical state by exposure to electromagnetic radiation. One of the more common consumer examples of a photochromic material are transition glasses. The lenses in the frames of these glasses are clear under artificial lighting conditions; however, when exposed to UV radiation generated by the sun, they become increasingly more opaque and block out a portion of the sunlight. This effect is created by the addition of crystalline halide inclusions within the glass that react to the UV radiation, which in turn, creates the opaque finish. This same principle can even be used to create colorful motifs on various consumer goods. This presentation will discuss the results of examinations of multiple photochromic materials and how microscopy, along with chemical analysis, can be used to understand the basic principles of photochromism.
The “Sinkhole” Conundrum: Legal Challenges to XRD-SEM Evidence for Liability for
Substructure Soil Collapse
Wayne C. Isphording — University of South Alabama and Tulane University
A ongoing confrontation exists when claims for coverage for property damage are challenged by companies who defend wording in insurance policies, even when that wording is shown to be ambiguous. This problem is especially common in areas where subsidence has taken place due to dissolution of the substrate by the action of groundwater.
Unfamiliarity with the nuances of geochemical systems, for example, results in attorneys believing that all subsidence resulting from groundwater solution takes place on either limestone or gypsiferous-rich bedrock. The idea that other types of rock, such as sandstones, argillaceous sediments, granites, or even peridotites can undergo incongruent dissolution and give rise to topographic features typical of “karst terranes” is totally foreign to them and, understandably, beyond their normal “expertise.” Therefore, they react negatively when insurance policies that restrict subsidence coverage to structures located on “limestone, or similar rock” are challenged by plaintiffs, whose subsidence damage has taken place beneath structures constructed on non-carbonate rocks. Ambiguity in a legal document, however, must always be interpreted in favor of the “non-drafter of the contract.” Such was the case for a home in Mobile, AL built on argillaceous sediments belonging to the Plio-Pleistocene Citronelle Formation, a Gulf Coastal Plain unit that extends from Mississippi, eastward through Alabama, Florida, and Georgia. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses reveal that the sediments of this unit are composed chiefly of quartz and kaolinite, but also contain abundant gibbsite. The origin of the gibbsite has been identified as resulting from the incongruent dissolution of kaolinite by the reaction shown below:
Al2Si2O5(OH)4 + 5H2O —-> 2Al(OH)3 + 2H4SiO4(aq)
S.G. 2.6 (258 amu) S.G. 2.4 (78 amu)
The irreversible mass transfer associated with the above reaction, and the concurrent volume change of solids, amounts to 34.6%. As such, it is wholly sufficient to explain the settlement phenomenon that has and continues to take place beneath the home. Therefore, it accurately substantiates that the settlement and subsoil collapse resulted from “subterranean voids created by the action of water on limestone or similar rock formations ” [author’s italics] and, therefore, should be covered by the policy purchased by the homeowner. The jury accepted the arguments proffered by the plaintiff’s expert witness.
The Effect of Ultraviolet Radiation on the Microspectrophotometry (MSP) of Dyed Fibers, Part 1: Photobleaching Effect
Meggan B. King — McCrone Research Institute
Patrick Buzzini and Carrie Polston — Sam Houston State University
Single fibers from a collection of 53 textile samples were analyzed using microspectrophotometry (MSP) after undergoing controlled, instrument-induced photobleaching. The sample set consists of 20 nylon, 14 polyester, eight acrylic, six viscose rayon, and five acetate rayon fiber types dyed with a variety of colors (15 yellow, 14 red, 11 blue, four orange, four violet, three brown, one black, and one green) and dye-application classes (29 disperse, 10 basic, six acid, five direct, two mordant, and one reactive). The dyed fibers were each exposed to the xenon light source on a CRAIC FLEX UV-visible-NIR microspectrophotometer for times ranging from 0 to about 3,700 seconds, with spectra collected every 60 seconds. Spectral alterations were observed in all but one sample. Spectral alterations occurred at different times ranging from about 20 seconds and 1,730 seconds. Spectral changes occurred in various forms: band shifts in the x-axis (wavenumber units) were commonly observed, and cases where spectral shapes were preserved but the overall intensity of all the bands was out of the range of the intra-source variation of spectra collected without further exposing the fibers to the excitation radiations. Changes in intensity values of one or few bands within a spectrum were also observed. Effects of band flattening, bump formation, bands fusion, slope change, and band disappearance were also noted. Combinations of the aforementioned spectral alteration modes were also recorded. In 28 instances, spectral alterations were observed in the visible range of the spectrum, while in 13 samples such changes were observed in the short UV range. In nine cases, spectral changes were observed in both the UV and visible ranges, where they did occur at different times. This research was funded by the National Institute of Justice (Award No. NIJ-2016-DN-0145).
Hacking a Dinosaur: Upgrading a Vintage Microscope Using the Raspberry Pi
Martin Kocanda — Rapid City Police Department, South Dakota
Vintage microscopes have occasionally surfaced on the surplus market. With some effort, the scopes can be rebuilt, but retrofitting them for photomicrography with commercial hardware can be challenging. With the availability of low-cost, single-board computers, camera peripherals, PVC fittings, and some programming experience, an older compound microscope can be upgraded to capture quality video and images. Using a Raspberry Pi 3, an open-source hardware and software platform, a digital imaging system is easily retrofitted for under $75.