79 research outputs found

    Physical and chemical trace evidence from 3d-printed firearms, and use of a quadcopter for targeted sampling of gaseous mercury in the atmosphere

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    My forensic research resulted in the first peer-reviepaper to address the forensic challenges presented by 3D-printed polymer firearms. The work involved a systematic approach to the analysis of evidence stemming from 3D-printed firearms filling a critical void in current forensic knowledge. We used DART-MS to characterize the polymer evidence left behind by 3D-printed firearms as well as an evaluation of pre-existing firearm and toolmark techniques and fingerprint analysis. We demonstrated that 3D-printed firearms leave behind characteristic polymer residue on cartridge cases bullets and the receiving surface which can be identified using DART-MS. The culmination of the work includes a database / reference library that can give forensic practitioners the ability to identify and source unknown polymer evidence using chemometric analysis including principle component analysis (PCA) and ongoing work with supervised statistical classification methods. Several novel analytical methods were developed in the course of this dissertation work including forensic analysis of trace chemical evidence from 3D-printed firearms using direct analysis in real time-mass spectrometry (DART-MS) and targeted aerial sampling for quantitation of gaseous mercury. The mercury project utilized a quadcopter unmanned aerial vehicle (UAV) and gold-coated quartz sorbent tubes to target and capture gaseous mercury which was then quantified both in the laboratory and in the field using cold vapor atomic fluorescence spectrometry (CVAFS). This method was verified to effectively capture and quantify mercury in the atmosphere near point sources and was applied near a coal-fired power plants petroleum refinery and municipal landfill. Average concentrations (± standard deviation) immediately downwind of the landfill were higher at ground level and 30 m compared to 60 m and 120 m (5.3 ± 0.5 ng m-3 5.4 ± 0.7 ng m-3 4.2 ± 0.7 ng m-3 and 2.5 ± 0.3 ng m-3 respectively). Concentrations were also higher at an urban/industrial area (Memphis) (3.3 ± 0.9 ng m-3) compared with a rural/background area (1.5 ± 0.2 ng m-3). Overall we shothe method is useful to probe Hg concentrations aloft and quantify emissions from potential point sources in the field using an inexpensive quadcopter and sampling setup. The forensic research was funded by NIJ Graduate Research Fellowship (Award # 2017-IJ-CX-0001). The opinions findings and conclusions or recommendations expressed here are those of the authors and do not necessarily reflect those of the U.S. Department of Justice

    High-throughput estimation of plant height and above-ground biomass of cotton using digital image analysis and Canopeo

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    Plant height and above-ground biomass are important growth parameters that affect crop yield. Efficient and non-destructive technologies of crop phenotypic monitoring play crucial roles in intelligent farmland management. However, the feasibility of using these technologies to estimate cotton plant height and above-ground biomass has not been determined. This study proposed a low cost and high-throughput imaging method combined with Canopeo to extract the percentages of green color from high-definition digital images and establish a model to estimate the cotton plant height and above-ground biomass. The plant height and above-ground biomass field trials were conducted at two levels of irrigation (soil water content 70% ± 5% and 40%−45%, respectively) using 80 cotton genotypes. The linear fitting performed well across the different cotton genotypes (PH, R2 = 0.9829; RMSE = 2.4 cm; NRMSE = 11% and AGB, R2 = 0.9609; RMSE = 0.6 g / plant; and NRMSE = 5%), and two levels of irrigation (PH, R2 = 0.9604; RMSE = 2.15 cm; NRMSE = 6% and AGB, R2 = 0.9650; RMSE = 4.51 g/plant; and NRMSE = 17%). All reached a higher fitting degree. Additionally, the most comprehensive model to estimate the cotton plant height and above-ground biomass (Y = 0.4832*X + 11.04; Y = 0.4621*X − 0.3591) was determined using a simple linear regression modeling method. The percentages of green color positively correlated with plant height and above-ground biomass, and each model exhibited higher accuracy (R2 ≄ 0.8392, RMSE ≀ 0.0158, NRMSE ≀ 0.06%). Combining a high-definition digital camera with Canopeo enables the prediction of crop growth in the field. The simple linear regression modeling method and the most comprehensive model enable the rapid estimation of the cotton plant height and above-ground biomass. This method can also be used as a baseline to measure other important crop phenotypes

    Laser-induced breakdown spectroscopy in Asia

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    Laser-induced breakdown spectroscopy (LIBS) is an analytical detection technique based on atomic emission spectroscopy to measure the elemental composition. LIBS has been extensively studied and developed due to the non-contact, fast response, high sensitivity, real-time and multi-elemental detection features. The development and applications of LIBS technique in Asia are summarized and discussed in this review paper. The researchers in Asia work on different aspects of the LIBS study in fundamentals, data processing and modeling, applications and instrumentations. According to the current research status, the challenges, opportunities and further development of LIBS technique in Asia are also evaluated to promote LIBS research and its applications

    Abstracts of Papers Presented at the 2005 Pittsburgh Conference

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    To attend or not to attend, that is the question. The Pittsburgh Conference continues to pose this conundrum to conferees and exhibitors alike. This year's conference was the first to be presented without a set of paper abstracts—a good thing some would say but this old codger always used the paper abstracts to select papers of interest to our readership and to seek a full publication. The exhibit took its usual format but it seemed that there were less manufacturers present. The information presented to the attendees was also lacking and many companies' details were missing from the final program book, an omission no doubt on their behalf—my company was one of these—however I feel sure that past Pittcon organizers would have been more persistent in getting the required details for the audience. As is now the norm, many of the presentations take the form of posters displayed within the exhibition area. Without a driver to get the audience there, the traffic was slow, to say the least. Lecture presentations were also attended in a mixed fashion. So the Pittsburgh Conference show moves on, and again next year it will be held in Orlando from 12 March to 17 March 2006. No doubt I will be there making it a straight 31 in a row; in Pittsburgh Conference terms I am just a beginner with many of the attendees making more shows in a run than that. Selected abstracts dealing with topics of interest to the readers of this journal follow—hopefully many of these groups will be willing to publish their work either within this journal or elsewhere

    NUC BMAS Sciences PG

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    Volume 03

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    Introduction from Dean Dr. Charles Ross Little Shop of Horrors by Longwood Theater Department Who Has the Hottest Hotsauce in Farmville: A Quantitative Comparison of Sauces from Local Restaurants by Cheryl Peck and Charles Hoever Precipitation Effects on the Growth of White Oaks and Virginia Pines on the Mt. Vernon Plantation by Brittany Anderson Design and Synthesis of Novel Ion Binding Molecules for Self-Assembly and Sensing Applications by J. Ervin Sheldon A Statistical Analysis of Algorithms for Playing SameGame by Richard Hayden Intersecting Cylinders at Arbitrary Angles by Yuri Calustro Putting a Foot in the Revolving Door: Strategies for Reducing Teacher Attrition by Candice Fleming and Rebecca Franklin The Effect of Presentation on Spanish Vocabulary Recall by Ashley Yocum How Attractive Are You? Individuals Sensitivity to Number of Sexual Partners by Danielle M. Jagoda and Cristina M. Valdivieso Culturally Relevant Practices for Teaching Code-Switching to African-American Students in Kindergarten Classrooms by Jameka Jones Two Poems – “Dust” and “Check Out Girls” by Amy Ellis Three Poems – “Rosewood Massacre, 1923”, “Jarring” and “Reverence” by Ashley Maser Three Poems – “Dirty Thunderstorm”, “Summer Hide \u27N Seek Car Tag” and “Bliss” by Erikk Shupp Analysis of the Wilton Diptych by Jamie Yurasits “Nod”, “Corriline” “Flying” “Familiar” by Alexander Leonhart Papermaking by Kenny Wolfe and Sally Meadows “Plant” by J. Haley, Amy Jackson, and Morgan Howard “Dare to Dart” by Amy Jackson, Adrienne Heinbaugh and Melissa Dorton Untitled Photographs by Hopson “Lockets” by Morgan Howard Graphic Designs and Untitled Photographs by Ciarra Stalker Selections from a Senior Recital by Joshua Davi

    Aiding the conservation of two wooden Buddhist sculptures with 3D imaging and spectroscopic techniques

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    The conservation of Buddhist sculptures that were transferred to Europe at some point during their lifetime raises numerous questions: while these objects historically served a religious, devotional purpose, many of them currently belong to museums or private collections, where they are detached from their original context and often adapted to western taste. A scientific study was carried out to address questions from Museo d'Arte Orientale of Turin curators in terms of whether these artifacts might be forgeries or replicas, and how they may have transformed over time. Several analytical techniques were used for materials identification and to study the production technique, ultimately aiming to discriminate the original materials from those added within later interventions

    3rd International Workshop on Instrumentation for Planetary Missions : October 24–27, 2016, Pasadena, California

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    The purpose of this workshop is to provide a forum for collaboration, exchange of ideas and information, and discussions in the area of the instruments, subsystems, and other payload-related technologies needed to address planetary science questions. The agenda will compose a broad survey of the current state-of-the-art and emerging capabilities in instrumentation available for future planetary missions.Universities Space Research Association (USRA); Lunar and Planetary Institute (LPI); Jet Propulsion Laboratory (JPL)Conveners: Sabrina Feldman, Jet Propulsion Laboratory, David Beaty, Jet Propulsion Laboratory ; Science Organizing Committee: Carlton Allen, Johnson Space Center (retired) [and 12 others

    Environmental Systems Research Candidates Program--FY2000 Annual report

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    X-ray fluorescence applied to yellow pigments based on lead, tin and antimony: comparison of laboratory and portable instrumentation

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    X-ray fluorescence is a diagnostic approach particularly suited to be utilized in cultural heritage sector since it falls in the non-destructive and non-invasive analytical tools. However there are big differences between portable and laboratory instrumentation that make difficult to perform a comparison in terms of quality and reliability of the results. The present study is specifically addressed to investigate these differences in respect of the same analytical sample-set. To reach this goal a comparison was thus carried out between portable and bench top devices X-ray fluorescence devices and techniques were used on different type of yellow pigments based on lead, tin and antimony obtained in laboratory, reproducing the instructions described in “old” recipes, that is: i) mortar of lead and tin produced on the basis of the recipe 13 /c V of the “Manuscript of Danzica” and “ Li tre libri dell’arte del Vasaio” by Cipriano Piccolpasso; ii) two types of lead and tin yellow (Pb2SnO4 and PbSnO3) produced starting from the indications of the 272 and 273 recipes of the “Bolognese Manuscript”; iii) lead antimonate (Pb2Sb2O7) obtained by following the instructions of the Piccolpasso’s treatise and those contained on the “Istoria delle pitture in maiolica fatte in Pesaro e ne’ luoghi circonvicini di Giambattista Passeri” and finally iv) lead, tin and antimony yellow (Pb2SnSbO6,5) obtained starting from the information contained in the paper 30 R of “Manuscript of Danzica” [1]. The XRF analysis were performed using a laboratory instrumentation (Bruker M4 Tornado) and a handset analytical device (Assing Surface Monitor). In order to perform a significant statistical comparison among acquired and processed data, all the analyses have been carried out utilizing the same sample, the same acquisition set up and operative conditions. A chemometric approach, based on the utilization of Principal Component Analysis (PCA) and multivariate analytical based tools [2], was utilized in order to verify the spectral differences, and related informative content, among the different produced yellow pigments. The multivariate approach on the results revealed instrumental differences between the two systems and allowed to compare the common characteristics of the set of pigments analyzed
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