61 research outputs found

    “Into and out of” the Qinghai‐Tibet plateau and the Himalayas: centers of origin and diversification across five clades of Eurasian montane and alpine passerine birds

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    Encompassing some of the major hotspots of biodiversity on Earth, large mountain systems have long held the attention of evolutionary biologists. The region of the Qinghai‐Tibet Plateau (QTP) is considered a biogeographic source for multiple colonization events into adjacent areas including the northern Palearctic. The faunal exchange between the QTP and adjacent regions could thus represent a one‐way street (“out of” the QTP). However, immigration into the QTP region has so far received only little attention, despite its potential to shape faunal and floral communities of the QTP. In this study, we investigated centers of origin and dispersal routes between the QTP, its forested margins and adjacent regions for five clades of alpine and montane birds of the passerine superfamily Passeroidea. We performed an ancestral area reconstruction using BioGeoBEARS and inferred a time‐calibrated backbone phylogeny for 279 taxa of Passeroidea. The oldest endemic species of the QTP was dated to the early Miocene (ca. 20 Ma). Several additional QTP endemics evolved in the mid to late Miocene (12–7 Ma). The inferred centers of origin and diversification for some of our target clades matched the “out of Tibet hypothesis’ or the “out of Himalayas hypothesis” for others they matched the “into Tibet hypothesis.” Three radiations included multiple independent Pleistocene colonization events to regions as distant as the Western Palearctic and the Nearctic. We conclude that faunal exchange between the QTP and adjacent regions was bidirectional through time, and the QTP region has thus harbored both centers of diversification and centers of immigration

    Next Generation Bipolar Plates for Automotive PEM Fuel Cells

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    The results of a successful U.S. Department of Energy (DoE) funded two-year 2.9MMprogramleadbyGrafTechInternationalInc.(GrafTech)arereportedandsummarized.Theprogramgoalwastodevelopthenextgenerationofhightemperatureprotonexchangemembrane(PEM)fuelcellbipolarplatesforuseintransportationfuelcellapplicationsoperatingattemperaturesupto120°C.ThebipolarplatecompositedevelopedduringtheprogramisbasedonGrafTech’sGRAFCELLresinimpregnatedflexiblegraphitetechnologyandmakesuseofahightemperatureHuntsmanAdvancedMaterialsresinsystemwhichextendstheupperusetemperatureofthecompositetotheDoEtarget.Hightemperatureperformanceofthenewcompositeisachievedwiththeaddedbenefitofimprovementsinstrength,modulus,anddimensionalstabilityovertheincumbentresinsystems.Otherphysicalproperties,includingthermalandelectricalconductivityofthenewcompositeareidenticaltoornotadverselyaffectedbythenewresinsystem.Usingthenewbipolarplatecompositesystem,machinedplateswerefabricatedandtestedinhightemperaturesingle−cellfuelcellsoperatingat120°Cforover1100hoursbyCaseWesternReserveUniversity.Finalverificationofperformancewasdoneonembossedfull−sizeplateswhichwerefabricatedandgluedintobipolarplatesbyGrafTech.Stacktestingwasdoneona10−cellfull−sizedstackunderasimulateddrivecycleprotocolbyBallardPowerSystems.Freeze−thawperformancewasconductedbyBallardonaseparate5−cellstackandshowntobewithinspecification.AthirdstackwasassembledandshippedtoArgonneNationalLaboratoryforindependentperformanceverification.ManufacturingcostestimatefortheproductionofthenewbipolarplatecompositeatcurrentandhighvolumeproductionscenarioswasperformedbyDirectedTechnologiesInc.(DTI).TheproductioncostestimateswereconsistentwithpreviousDoEcostestimatesperformedbyDTIfortheDoEonmetalplates.ThefinalresultofDTI’sanalysisforthehighvolumemanufacturingscenario(2.9 MM program lead by GrafTech International Inc. (GrafTech) are reported and summarized. The program goal was to develop the next generation of high temperature proton exchange membrane (PEM) fuel cell bipolar plates for use in transportation fuel cell applications operating at temperatures up to 120 °C. The bipolar plate composite developed during the program is based on GrafTech’s GRAFCELL resin impregnated flexible graphite technology and makes use of a high temperature Huntsman Advanced Materials resin system which extends the upper use temperature of the composite to the DoE target. High temperature performance of the new composite is achieved with the added benefit of improvements in strength, modulus, and dimensional stability over the incumbent resin systems. Other physical properties, including thermal and electrical conductivity of the new composite are identical to or not adversely affected by the new resin system. Using the new bipolar plate composite system, machined plates were fabricated and tested in high temperature single-cell fuel cells operating at 120 °C for over 1100 hours by Case Western Reserve University. Final verification of performance was done on embossed full-size plates which were fabricated and glued into bipolar plates by GrafTech. Stack testing was done on a 10-cell full-sized stack under a simulated drive cycle protocol by Ballard Power Systems. Freeze-thaw performance was conducted by Ballard on a separate 5-cell stack and shown to be within specification. A third stack was assembled and shipped to Argonne National Laboratory for independent performance verification. Manufacturing cost estimate for the production of the new bipolar plate composite at current and high volume production scenarios was performed by Directed Technologies Inc. (DTI). The production cost estimates were consistent with previous DoE cost estimates performed by DTI for the DoE on metal plates. The final result of DTI’s analysis for the high volume manufacturing scenario (6.85 /kW) came in slightly above the DoE target of 3to3 to 5/kW. This estimate was derived using a “Best Case Scenario” for many of the production process steps and raw material costs with projections to high volumes. Some of the process improvements assumed in this “Best Case Scenario” including high speed high impact forming and solvent-less resins, have not yet been implemented, but have a high probability of potential success

    Diverse Applications of Nanomedicine

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    The design and use of materials in the nanoscale size range for addressing medical and health-related issues continues to receive increasing interest. Research in nanomedicine spans a multitude of areas, including drug delivery, vaccine development, antibacterial, diagnosis and imaging tools, wearable devices, implants, high-throughput screening platforms, etc. using biological, nonbiological, biomimetic, or hybrid materials. Many of these developments are starting to be translated into viable clinical products. Here, we provide an overview of recent developments in nanomedicine and highlight the current challenges and upcoming opportunities for the field and translation to the clinic. \ua9 2017 American Chemical Society

    Introduction of Fluorine and Fluorine-Containing Functional Groups

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    Phylogenetic relationships of endemic bunting species (Aves, Passeriformes, Emberizidae, Emberiza koslowi) from the eastern Qinghai-Tibet Plateau

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    In this study we reconstructed the phylogenetic relationships of a narrow-range Tibetan endemic, Emberiza koslowi, to its congeners and shed some light on intraspecific lineage separation of further bunting species from Far East Asia and along the eastern margin of the Tibetan Plateau in China. The onset of the Old World bunting radiation was dated to the mid Miocene and gave rise to four major clades: i) one group comprising mainly Western Palearctic species and all high-alpine endemics of the Tibetan Plateau; ii) a clade including E. lathami, E. bruniceps and E. melanocephala; iii) one group comprising mainly Eastern Palearctic species and all insular endemics from Japan and Sakhalin; iv) an exclusively Afrotropic clade that comprised all African species except E. affinis, whose phylogenetic relationships were ambiguous and only poorly supported in all reconstructions. The Tibetan bunting, E. koslowi, turned out as an early offshoot of the Western Palearctic-Tibetan clade 1 and thus represents an ancient relic lineage that dates back to a mid Miocene colonization event of its ancestors to the alpine plateau habitats. This temporal scenario of an early Miocene origin of alpine Tibetan endemics coincides with recent results for two further species, the Tibetan ground tit, Pseudopodoces humilis, and the Tibetan rosefinch, Carpodacus roborowskii. The origin of extant intraspecific phylogeographic patterns and splits among sister species in Eastern Asia were dated back to the Pleistocene with earliest lineage splits occurring among taxa from the Japanese Archipelago including Sakhalin and their mainland counterparts. A similarly ancient split separated a southern clade of E. godlewskii yunnanensis from S Sichuan and Yunnan from a northern clade including populations from central and northeastern China, Mongolia and S Siberia. Ecological segregation among breeding habitats of southern E. g. yunnanensis at lower elevations and those of other conspecifics at high-alpine habitats might have played a key role in the spatial genetic diversification of this species

    Non-destructive assay of nuclear waste containers using muon scattering tomography in the Horizon2020 CHANCE project

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    Methods for the non-destructive assay of nuclear waste drums are of great importance to the nuclear waste management community, especially where loss in continuity of knowledge about the content of drums happened or chemical processes altering the contents of the drums may occur. Muon scattering tomography has been shown to be a promising technique for the non-destructive assay of nuclear waste drums in a safe way. By measuring tracks of muons entering and leaving the probed sample and extracting scattering angles from the tracks, it is possible to draw conclusions about the contents of the sample and its spatial arrangement. Within the CHANCE project, a newly built large-scale mobile detector system for scanning and imaging the contents of nuclear waste drums using atmospheric muons is currently undergoing commissioning
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