The Experts below are selected from a list of 6852 Experts worldwide ranked by ideXlab platform
Troy Erns - One of the best experts on this subject based on the ideXlab platform.
-
forensic analysis of glass by μ xrf sn icp ms la icp ms and la icp oes evaluation of the performance of different criteria for comparing elemental composition
Journal of Analytical Atomic Spectrometry, 2013Co-Authors: Tatiana Trejos, Robe D Koons, Pete Weis, Stefa Ecke, Ted Erma, Claude Dalpe, Marc Duecking, Joa Uscaglia, Tiffany Eckertlumsdo, Troy ErnsAbstract:Four interlaboratory tests were designed to evaluate the performance of Match criteria for forensic comparisons of elemental composition of glass by μ-XRF, solution nebulization SN-ICP-MS, LA-ICP-OES and LA-ICP-MS. A total of 24 analysts in 18 laboratories participated in the tests. Glass specimens were selected to study the capabilities of the techniques to discriminate glass produced in the same manufacturing plant at different time intervals and to associate samples that originated from a single source. The assessment of the effectiveness of several Match criteria included: confidence interval (±6s, ±5s, ±4s, ±3s, ±2s), modified confidence interval, t-test, range overlap, and Hotelling's T2. Error rates are reported for each of these criteria. Recommended Match criteria were those found to produce the lowest combinations of type 1 and type 2 error rates. Performance of the studied Match criteria was dependent on the homogeneity of the glass sources, the repeatability between analytical measurements, and the number of elements that were measured. The best results for μ-XRF data were obtained using spectral overlay followed by a ±3s confidence interval or range overlap. For ICP-based measurements, a wider Match Criterion, such as a modified confidence interval based on a fixed minimum relative standard deviation (±4s, >3–5% RSD), is recommended due to the inherent precision of those methods (typically <1–5% RSD) and the greater number of elements measured. Glass samples that were manufactured in different plants, or at the same plant weeks or months apart, were readily differentiated by elemental composition when analyzed by these sensitive methods.
Jose R Almirall - One of the best experts on this subject based on the ideXlab platform.
-
elemental analysis of glass by laser ablation inductively coupled plasma optical emission spectrometry la icp oes
Forensic Science International, 2012Co-Authors: Emily R Schenk, Jose R AlmirallAbstract:The elemental analysis of glass evidence has been established as a powerful discrimination tool for forensic analysts. Laser ablation inductively coupled plasma optical emission spectrometry (LA-ICP-OES) has been compared to laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and energy dispersive micro X-ray fluorescence spectroscopy (μXRF/EDS) as competing instrumentation for the elemental analysis of glass. The development of a method for the forensic analysis of glass coupling laser ablation to ICP-OES is presented for the first time. LA-ICP-OES has demonstrated comparable analytical performance to LA-ICP-MS based on the use of the element menu, Al (Al I 396.15 nm), Ba (Ba II 455.40 nm), Ca (Ca II 315.88 nm), Fe (Fe II 238.20 nm), Li (Li I 670.78 nm), Mg (Mg I 285.21 nm), Sr (Sr II 407.77 nm), Ti (Ti II 368.51 nm), and Zr (Zr II 343.82 nm). The relevant figures of merit, such as precision, accuracy and sensitivity, are presented and compared to LA-ICP-MS. A set of 41 glass samples was used to assess the discrimination power of the LA-ICP-OES method in comparison to other elemental analysis techniques. This sample set consisted of several vehicle glass samples that originated from the same source (inside and outside windshield panes) and several glass samples that originated from different vehicles. Different Match criteria were used and compared to determine the potential for Type I and Type II errors. It was determined that broader Match criteria is more applicable to the forensic comparison of glass analysis because it can reduce the affect that micro-heterogeneity inherent in the glass fragments and a less than ideal sampling strategy can have on the interpretation of the results. Based on the test set reported here, a plus or minus four standard deviation (± 4s) Match Criterion yielded the lowest possibility of Type I and Type II errors. The developed LA-ICP-OES method has been shown to perform similarly to LA-ICP-MS in the discrimination among different sources of glass while offering the advantages of a lower cost of acquisition and operation of analytical instrumentation making ICP-OES a possible alternative elemental analysis method for the forensic laboratory.
Carlos Viviani - One of the best experts on this subject based on the ideXlab platform.
-
misMatch between classroom furniture and anthropometric measures in chilean schools
Applied Ergonomics, 2010Co-Authors: H I Castellucci, P Arezes, Carlos VivianiAbstract:Children spend about five hours per day sitting down while doing their school work. Considering this as well as the potential inadequate use of school furniture, it is likely that some anatomical-functional changes and problems in the learning process may occur. The aim of this study was to compare furniture sizes within three different schools with the anthropometric characteristics of Chilean students in the Valparaiso region, in order to evaluate the potential misMatch between them. The sample consisted of 195 volunteer students (94 male, 101 female) of the 8th grade, ranging from 12.5 to 14.5 years of age from 3 different schools. Regarding the methodology, 6 anthropometric measures (Stature, Popliteal height, Buttock-popliteal length, Elbow height while sitting, Hip width, Thigh thickness and Subscapular height) were gathered, as well as 8 dimensions from the school furniture. For the evaluation of classroom furniture a Match Criterion equation was defined. After considering the existing classroom furniture dimensions in each Match Criterion equation, the anthropometric characteristics of the considered population were compared in order to determine the misMatch between them. Results indicated that seat height, which should be considered as the starting point for the design of classroom furniture, was appropriate for students' popliteal height in only 14% of the 2 out of the 3 schools, and 28% in the third. Seat to desk height was too high and misMatched 99% of the students in one school and 100% in the others. Therefore, it was possible to conclude that the classroom's furniture was inadequate in almost all the analyzed cases and subjects. It is possible that the high misMatch percentage found between furniture and students' anthropometry can be associated to the fact that the acquisition and selection of the furniture was made without any ergonomic concern or criteria.
Samira Bahrampour - One of the best experts on this subject based on the ideXlab platform.
-
classroom furniture and anthropometric characteristics of iranian high school students proposed dimensions based on anthropometric data
Applied Ergonomics, 2013Co-Authors: Iman Dianat, Mohammad Karimi, Ahmad Asl Hashemi, Samira BahrampourAbstract:Abstract The study evaluated the potential misMatch between classroom furniture dimensions and anthropometric characteristics of 978 Iranian high school students (498 girls, 480 boys), aged 15–18 years. Nine anthropometric measurements (stature, sitting height, sitting shoulder height, popliteal height, hip breadth, elbow–seat height, buttock–popliteal length, buttock–knee length and thigh clearance) and five dimensions from the existing classroom furniture were measured and then compared together (using Match Criterion equations) to identify any potential misMatch between them. The results indicated a considerable misMatch between body dimensions of the students and the existing classroom furniture, with seat height (60.9%), seat width (54.7%) and desktop height (51.7%) being the furniture dimensions with a higher level of misMatch. The levels of misMatch varied between the high-school grade levels and between genders, indicating their special requirements and possible problems. The proposed dimensions of the classroom furniture more appropriate for the students were given. This additional information on students’ anthropometry can be used by local furniture industries as a starting point for designing more appropriate furniture for school children, or used by schools to aid in furniture selection.
Tatiana Trejos - One of the best experts on this subject based on the ideXlab platform.
-
forensic analysis of glass by μ xrf sn icp ms la icp ms and la icp oes evaluation of the performance of different criteria for comparing elemental composition
Journal of Analytical Atomic Spectrometry, 2013Co-Authors: Tatiana Trejos, Robe D Koons, Pete Weis, Stefa Ecke, Ted Erma, Claude Dalpe, Marc Duecking, Joa Uscaglia, Tiffany Eckertlumsdo, Troy ErnsAbstract:Four interlaboratory tests were designed to evaluate the performance of Match criteria for forensic comparisons of elemental composition of glass by μ-XRF, solution nebulization SN-ICP-MS, LA-ICP-OES and LA-ICP-MS. A total of 24 analysts in 18 laboratories participated in the tests. Glass specimens were selected to study the capabilities of the techniques to discriminate glass produced in the same manufacturing plant at different time intervals and to associate samples that originated from a single source. The assessment of the effectiveness of several Match criteria included: confidence interval (±6s, ±5s, ±4s, ±3s, ±2s), modified confidence interval, t-test, range overlap, and Hotelling's T2. Error rates are reported for each of these criteria. Recommended Match criteria were those found to produce the lowest combinations of type 1 and type 2 error rates. Performance of the studied Match criteria was dependent on the homogeneity of the glass sources, the repeatability between analytical measurements, and the number of elements that were measured. The best results for μ-XRF data were obtained using spectral overlay followed by a ±3s confidence interval or range overlap. For ICP-based measurements, a wider Match Criterion, such as a modified confidence interval based on a fixed minimum relative standard deviation (±4s, >3–5% RSD), is recommended due to the inherent precision of those methods (typically <1–5% RSD) and the greater number of elements measured. Glass samples that were manufactured in different plants, or at the same plant weeks or months apart, were readily differentiated by elemental composition when analyzed by these sensitive methods.