Volume 18. Number 1
Application of Multi-Element Scanning Thermal Analysis (MESTA) Method in Tire Identification for Forensic Purposes
Chiou-Herr Yang; Yuch-Ping Hsieh; Yung-Fou Chen; Wei-Lun Yan
accidents or criminal cases may lead car to leave tire samples or tire marks on
an accident scene or a criminal scene. Tire samples left in a scene can be a
valuable source of information that links an accident or criminal scene to the
suspected vehicle. However, it is difficult to analyze a tire sample in detail
for forensic purposes by chemical method or spectroscopic method due to its low
solubility in solvents and dark color. The objective of this study was to
explore the feasibility of using the multi-element scanning thermal analysis
(MESTA) for tire samples identification in forensic science. In this study, 13
tire samples were collected randomly from various sources. Powder samples were
scraped from tire surfaces by files. The scraped powder was analyzed by the
MESTA method. The MESTA C, N and S thermograms in the three temperature regions,
namely, 250-450 ¢XC, 451-590 ¢XC and 590-710 ¢XC were chosen as the temperature
interval for analysis. The result of statistical analysis shown that there is
significant variations among the total C (carbon), N (nitrogen), S (sulfur)
concentrations and peaks ratio to differentiate those tire samples. Totally,
there are 12 parameters that can be used to distinguish one sample from others.
Principal component analysis (PCA) and hierarchical clusters analysis (HCA) were
performed for discriminating different tire samples. Results shown that the
combination of MESTA and HCA can be a potential technique for distinguish tire
samples that are from different sources.
Yi-Ching Chen; Yung-Fou Chen; Hsing-Mei Hsieh; Li-Chin TsaiAbstract¡G Metabolomics is regarded as a new approach for studying the composition of cells, tissues, or even the entire set of meta- bolic molecules in vivo after Genomics and Proteomics. Recently, there have been several papers analyzing specific metabolites in different body fluids by liquid or gas chromatography¡Vmass spectrometry (LC-MS or GC-MS), nuclear magnetic resonance (NMR), and other ways. These diverse sets of metabolites may be potential as specific biomarkers for body fluid identification. This report summarized the research related to body fluid metabolites in published papers, and also reported the current MS and NMR papers, which were the current established analytical techniques for metabolome analyses of body fluids. Furthermore, the potential of these technologies for being applied to forensic body fluid differentiation was evaluated in this report.
Ting-Chia Chang; Chien-Tung Chen; Wei-Tun Chang
Abstract¡G Past cases have shown that the faking of 58¢XKinmen Kaoliang Liquor (58¢XKKL), a type of sorghum liquor, is usually dominated by adulteration, in two forms concerning the use of bottle labels: 1) recycling old bottles with authentic bottle labels and 2) sticking fake bottle labels on bottles. A complete and systematic authentication procedure of 58¢XKKL usually requires analyses to be performed on the bottle cap, bottle label, and liquor. However, this study focuses on analytical methods for the identification of bottle label, with physical identification methods involving ultraviolet (UV) light source, digital microscope, video spectral comparator (VSC), and with chemical identification methods involving X-ray fluorescence spectrometer (XRF), scanning electron microscope/energy dispersive X-ray spectroscopy (SEM/EDS). By using these complementary and comparative analytical methods, a total of 12 features with discriminative value were obtained, based on which an analytical strategy for the authentication of 58¢XKKL bottle label was established to improve the credibility of evidence.
Pei-Chen Lin; Che-Yen Wen
Abstract¡G Gunshot detection has been one of important research topics in military and law enforcement applications. It has been used to detect the direction and localization of shooting events. In audio analysis, it plays an important role of finding the possible gun - shot time period, called gunshot audio segmentation. The short-time energy function (STE) and the zero-crossing rate function (ZCR) are useful methods for voiced and unvoiced detection. We can use STE and ZCR to detect signals with the strong energy and highlight the sound period with rich detail. The quality of audio data may be affected by recording devices. However, in previous gunshot detection research work, most of their audio data were not collected by cellphones. Since many of audio data collected from criminal investigation cases are recorded by cellphones in Taiwan, we need to evaluate the performance of detec- tion methods. In this paper, we apply STE and ZCR to gunshot detection of audio recorded by cellphones (32 samples). From experimental results, we can obtain good results.
Characteristics of Gunshot Suicides in Three Taiwan Metropolises
Hsien-Hui Meng ; Yu-Ting Hsiao
Abstract¡G The differentiation between suicide and homicide is a key issue when investigating gunshot fatalities. We described the characteristics of gunshot suicides occurred in Taiwan to confirm the suicidal markers reported in foreign publications are applicable to the investigation of local gunshot fatalities. Thirty-seven gunshot suicide cases involving forty-two fatalities were examined. The results revealed that the information concerning the suicidal markers reported in prior literature such as the number and the location of entrance wound, shooting distance, the direction of bullet path, the location of weapon, the presence of back-spattered blood on the shooting hand and the firearms, detection of gunshot residues, and the presence of suicide note at the scene is particularly valuable. However, the main weapons used in gunshot suicides in Taiwan are homemade firearms rather than regular guns. Muzzle energy determination indicated that the lethality of local homemade pistols is similar to that of regular handguns. We recommended that the authority should take steps to eliminate illegal firearm manufacturing factories to re duce the firearm deaths2.