Browsing by Subject "sampling"

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    Mapping explosive residues on galvanized pipe bomb fragments using total vaporization solid phase microextraction (TV-SPME)
    (Royal Society of Chemistry, 2015-12) Bors, Dana; Goodpaster, John V.; Department of Chemistry and Chemical Biology, School of Science
    Solid phase microextraction (SPME) is a popular sampling technique whereby analytes are sorbed to a coated fiber and subsequently desorbed into an analytical instrument. In headspace SPME, analytes partition between the sample, the headspace above the sample, and the SPME fiber coating. In total vaporization SPME (TV-SPME), sample extracts are heated until both the solvent and analytes completely vaporize, whereupon the analytes partition between the vapor phase and the SPME fiber. In this study, TV-SPME using a polyethylene glycol fiber was coupled with fast gas chromatography/mass spectrometry to identify components of double-base smokeless powder (DBSP). Nitroglycerin (NG), diphenylamine (DPA) and ethyl centralite (EC) were separated in under 5 min. For NG, the optimal sample volume (70 μL), extraction temperature (60 °C) and extraction time (20 min) resulted in a method that was over twelve fold more sensitive than traditional liquid injection and with a detection limit below 1 ppb. This method was then used to quantify DBSP residue on post-blast debris from five galvanized steel pipe bombs. The mean concentration of NG on the fragments was 0.25 ppm (w/w). An average of 1.01 mg of NG was recovered from the devices. Finally, the distribution of NG could be “mapped” by tracking the original locations of each fragment within the device. These maps showed that the distribution of NG was far from uniform. In fact, the concentration of the NG on fragments originating from the end caps was several fold higher than in other locations. This finding can help guide the selection of bomb fragments for chemical analyses in real-world scenarios.
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    The Use of Online Panel Data in Management Research: A Review and Recommendations
    (Sage, 2019-01) Porter, Christopher O. L. H.; Outlaw, Ryan; Gale, Jake P.; Cho, Thomas S.; Kelley School of Business - Indianapolis
    Management scholars have long depended on convenience samples to conduct research involving human participants. However, the past decade has seen an emergence of a new convenience sample: online panels and online panel participants. The data these participants provide—online panel data (OPD)—has been embraced by many management scholars owing to the numerous benefits it provides over “traditional” convenience samples. Despite those advantages, OPD has not been warmly received by all. Currently, there is a divide in the field over the appropriateness of OPD in management scholarship. Our review takes aim at the divide with the goal of providing a common understanding of OPD and its utility and providing recommendations regarding when and how to use OPD and how and where to publish it. To accomplish these goals, we inventoried and reviewed OPD use across 13 management journals spanning 2006 to 2017. Our search resulted in 804 OPD-based studies across 439 articles. Notably, our search also identified 26 online panel platforms (“brokers”) used to connect researchers with online panel participants. Importantly, we offer specific guidance to authors, reviewers, and editors, having implications for both micro and macro management scholars.