The Experts below are selected from a list of 39696 Experts worldwide ranked by ideXlab platform
Gerd Wolz - One of the best experts on this subject based on the ideXlab platform.
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rapid identification of polystyrene foam wastes containing hexabromocyclododecane or its alternative polymeric brominated flame retardant by x ray Fluorescence Spectroscopy
Waste Management & Research, 2015Co-Authors: Martin Schlummer, Jorg Vogelsang, Dominik Fiedler, Ludwig Gruber, Gerd WolzAbstract:The brominated flame retardant hexabromocyclododecane (HBCDD) was added to Annex A of the list of persistent organic pollutants (POPs) of the Stockholm Convention. Thus, production and use of HBCDD will be banned, and the recycling of HBCDD-containing foam waste will be restricted. In reaction a special polymeric brominated flame retardant (PolyFR) was developed to replace HBCDD in expanded and extruded polystyrene foams for building and construction applications. A decision has to be made at some future time whether expanded and extruded polystyrene foam waste is to be subjected to incineration (with HBCDD) or to recycling (without HBCDD). Therefore, an appropriate and rapid field method is required to distinguish between foams containing HBCDD and foams free from HBCDD.Here we present a screening method for identifying HBCDD containing expanded and extruded polystyrene foams. The test principle is based on the fact that PolyFR (a brominated polymeric macromolecule) is not extractable whereas HBCDD (a lo...
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rapid identification of polystyrene foam wastes containing hexabromocyclododecane or its alternative polymeric brominated flame retardant by x ray Fluorescence Spectroscopy
Waste Management & Research, 2015Co-Authors: Martin Schlummer, Jorg Vogelsang, Dominik Fiedler, Ludwig Gruber, Gerd WolzAbstract:The brominated flame retardant hexabromocyclododecane (HBCDD) was added to Annex A of the list of persistent organic pollutants (POPs) of the Stockholm Convention. Thus, production and use of HBCDD will be banned, and the recycling of HBCDD-containing foam waste will be restricted. In reaction a special polymeric brominated flame retardant (PolyFR) was developed to replace HBCDD in expanded and extruded polystyrene foams for building and construction applications. A decision has to be made at some future time whether expanded and extruded polystyrene foam waste is to be subjected to incineration (with HBCDD) or to recycling (without HBCDD). Therefore, an appropriate and rapid field method is required to distinguish between foams containing HBCDD and foams free from HBCDD. Here we present a screening method for identifying HBCDD containing expanded and extruded polystyrene foams. The test principle is based on the fact that PolyFR (a brominated polymeric macromolecule) is not extractable whereas HBCDD (a low molecular weight substance) is extractable. Following rapid extraction of HBCDD the brominated flame retardant is identified and quantified via bromine analysis using a handheld X-Ray Fluorescence instrument. The method was applied successfully to 27 expanded and extruded polystyrene foam samples (foams and extruded polystyrene foam raw materials), which were provided without any information about the applied flame retardant. The presence of HBCDD was confirmed for all HBCDD-positive samples in the test. A robustness test revealed a high degree of correctness and a high repeatability for the test system: samples containing HBCDD and HBCDD-free samples were identified correctly with relative standard deviations of quantitative results below 14%. Moreover, X-Ray Fluorescence Spectroscopy test results agree well with HBCDD determinations performed in a laboratory with a gas chromatograph coupled to a flame ionisation detector.
Yoichiro Tsuji - One of the best experts on this subject based on the ideXlab platform.
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surface analysis of lanthanum strontium cobalt oxides under cathodic polarization at high temperature through operando total reflection x ray absorption and x ray Fluorescence Spectroscopy
Solid State Ionics, 2020Co-Authors: Yoichiro Tsuji, Shinnosuke Sako, Kiyofumi Nitta, Kentaro Yamamoto, Yang Shaohorn, Yoshiharu Uchimoto, Yuki OrikasaAbstract:Abstract The surface chemistry of perovskite-type lanthanum transition metal oxides is an important parameter in high-temperature electrochemical devices such as solid oxide fuel cells (SOFCs). Strontium segregation on the surface of lanthanum strontium cobalt oxides (LSC) may lead to poor oxygen reduction kinetics. However, previous studies have not sufficiently addressed the oxide surface chemistry, including the oxidation change of LSC under cathodic polarization. In this study, operando total-reflection X-Ray Fluorescence absorption and X-Ray Fluorescence Spectroscopy were performed to investigate cathodic polarization at high temperature (773 K) and at 1 atm pressure. Dense thin-film electrodes of La0.6Sr0.4CoO3 (LSC113) on Zr0.92Y0.08O1.96 electrolytes with a gadolinium-doped ceria interlayer were examined as model SOFC cathodes. This may be the first time that predominant surface reduction of cobalt is directly observed by using LSC113 under cathodic polarization. This phenomenon is related to strontium enrichment on the LSC surface. (La0.5Sr0.5)2CoO4 decoration on LSC113 enhanced the oxygen reduction kinetics compared with that of bare LSC113. This is due to the suppression of cobalt surface reduction and Sr enrichment in the LSC113 phase.
Brandon L Drake - One of the best experts on this subject based on the ideXlab platform.
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portable x ray Fluorescence Spectroscopy for rapid and cost effective determination of elemental composition of ground forage
Frontiers in Plant Science, 2019Co-Authors: Yadav Sapkota, Louis M Mcdonald, T C Griggs, Thomas J Basden, Brandon L DrakeAbstract:The recent development of portable X-Ray Fluorescence spectrometers (PXRF) has created new avenues for rapid plant elemental concentration determination at reduced cost while avoiding hazardous chemicals. A few studies have indicated the potential use of PXRF for homogenous plant tissue analysis. However, there is a lack of information for analysis of heterogeneous plant samples like livestock forage, which consists of a mixture of several species and plant parts, each varying in elemental concentration. Our objective was to evaluate PXRF for forage analysis, specifically the effect of forage particle size and scan time on important elements including P, K, Ca, and Fe determination. Hay samples (n=42) were oven dried (60oC for 3 days) and ground into three particle sizes (≤0.5 mm, 0.25-0.5 mm and 1-2 mm). Prepared samples were scanned by PXRF using a vacuum (<10 torr) without a filter. Samples were placed in cups over thin prolene X-Ray film and scanned for 180 seconds (s). A subset (n=29) were also scanned for 60 and 120 s. PXRF counts for P, K, Ca, and Fe were compared with laboratory Inductively Coupled Plasma Optical Emission Spectroscopy (ICP) determinations, using regression models. Results indicated that these elements could potentially be determined with PXRF (r2≥0.70) in heterogeneous forage samples. Relationship strength increased with decreasing particle size however, the relationship was still strong (r2≥0.57) at the largest particle size. Scanning time did not affect the relationship with ICP concentration for any of the particle sizes evaluated. This work demonstrated that with the right sample preparation PXRF can obtain results comparable to acid digestion and ICP regardless of sample composition, and suggests the potential for in-situ determinations.
Martin Pumera - One of the best experts on this subject based on the ideXlab platform.
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Searching for Magnetism in Hydrogenated Graphene: Using Highly Hydrogenated Graphene Prepared via Birch Reduction of Graphite Oxides
ACS nano, 2013Co-Authors: Alex Yong Sheng Eng, Hwee Ling Poh, Filip Šaněk, Miroslav Maryško, Stanislava Matějková, Zdeněk Sofer, Martin PumeraAbstract:Fully hydrogenated graphene (graphane) and partially hydrogenated graphene materials are expected to possess various fundamentally different properties from graphene. We have prepared highly hydrogenated graphene containing 5% wt of hydrogen via Birch reduction of graphite oxide using elemental sodium in liquid NH3 as electron donor and methanol as proton donor in the reduction. We also investigate the influence of preparation method of graphite oxide, such as the Staudenmaier, Hofmann or Hummers methods on the hydrogenation rate. A control experiment involving NaNH2 instead of elemental Na was also performed. The materials were characterized in detail by electron microscopy, infrared Spectroscopy, X-Ray photoelectron Spectroscopy, Raman Spectroscopy both at room and low temperatures, X-Ray Fluorescence Spectroscopy, inductively coupled plasma optical emission Spectroscopy, combustible elemental analysis and electrical resistivity measurements. Magnetic measurements are provided of bulk quantities of high...
Yuki Orikasa - One of the best experts on this subject based on the ideXlab platform.
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surface analysis of lanthanum strontium cobalt oxides under cathodic polarization at high temperature through operando total reflection x ray absorption and x ray Fluorescence Spectroscopy
Solid State Ionics, 2020Co-Authors: Yoichiro Tsuji, Shinnosuke Sako, Kiyofumi Nitta, Kentaro Yamamoto, Yang Shaohorn, Yoshiharu Uchimoto, Yuki OrikasaAbstract:Abstract The surface chemistry of perovskite-type lanthanum transition metal oxides is an important parameter in high-temperature electrochemical devices such as solid oxide fuel cells (SOFCs). Strontium segregation on the surface of lanthanum strontium cobalt oxides (LSC) may lead to poor oxygen reduction kinetics. However, previous studies have not sufficiently addressed the oxide surface chemistry, including the oxidation change of LSC under cathodic polarization. In this study, operando total-reflection X-Ray Fluorescence absorption and X-Ray Fluorescence Spectroscopy were performed to investigate cathodic polarization at high temperature (773 K) and at 1 atm pressure. Dense thin-film electrodes of La0.6Sr0.4CoO3 (LSC113) on Zr0.92Y0.08O1.96 electrolytes with a gadolinium-doped ceria interlayer were examined as model SOFC cathodes. This may be the first time that predominant surface reduction of cobalt is directly observed by using LSC113 under cathodic polarization. This phenomenon is related to strontium enrichment on the LSC surface. (La0.5Sr0.5)2CoO4 decoration on LSC113 enhanced the oxygen reduction kinetics compared with that of bare LSC113. This is due to the suppression of cobalt surface reduction and Sr enrichment in the LSC113 phase.
