NASA Astrophysics Data System (ADS)
Profe, Jörn; Ohlendorf, Christian
2017-04-01
XRF-scanning is the state-of-the-art technique for geochemical analyses in marine and lacustrine sedimentology for more than a decade. However, little attention has been paid to data precision and technical limitations so far. Using homogenized, dried and powdered samples (certified geochemical reference standards and samples from a lithologically-contrasting loess-paleosol sequence) minimizes many adverse effects that influence the XRF-signal when analyzing wet sediment cores. This allows the investigation of data precision under ideal conditions and documents a new application of the XRF core-scanner technology at the same time. Reliable interpretations of XRF results require data precision evaluation of single elements as a function of X-ray tube, measurement time, sample compaction and quality of peak fitting. Ten-fold measurement of each sample constitutes data precision. Data precision of XRF measurements theoretically obeys Poisson statistics. Fe and Ca exhibit largest deviations from Poisson statistics. The same elements show the least mean relative standard deviations in the range from 0.5% to 1%. This represents the technical limit of data precision achievable by the installed detector. Measurement times ≥ 30 s reveal mean relative standard deviations below 4% for most elements. The quality of peak fitting is only relevant for elements with overlapping fluorescence lines such as Ba, Ti and Mn or for elements with low concentrations such as Y, for example. Differences in sample compaction are marginal and do not change mean relative standard deviation considerably. Data precision is in the range reported for geochemical reference standards measured by conventional techniques. Therefore, XRF scanning of discrete samples provide a cost- and time-efficient alternative to conventional multi-element analyses. As best trade-off between economical operation and data quality, we recommend a measurement time of 30 s resulting in a total scan time of 30 minutes
[Study on trace elements of lake sediments by ICP-AES and XRF core scanning].
Cheng, Ai-Ying; Yu, Jun-Qing; Gao, Chun-Liang; Zhang, Li-Sha; He, Xian-Hu
2013-07-01
It is the first time to study sediment of Toson lake in Qaidam Basin. Trace elements including Cd, Cr, Cu, Zn and Pb in lake sediment were measured by ICP-AES method, studied and optimized from different resolution methods respectively, and finally determined a optimum pretreatment system for sediment of Toson lake, namely, HCl-HNO3-HF-HClO4-H2O2 system in the proportions of 5 : 5 : 5 : 1 : 1 was determined. At the same time, the data measured by XRF core scanning were compared, the use of moisture content correction method was analyzed, and the influence of the moisture content on the scanning method was discussed. The results showed that, compared to the background value, the contents of Cd and Zn were a little higher, the content of Cr, Cu and Pb was within the background value limits. XRF core scanning was controlled by sediment elements as well as water content in sediment to some extent. The results by the two methods showed a significant positive correlation, with the correlation coefficient up to 0.673-0.925, and they have a great comparability.
NASA Astrophysics Data System (ADS)
Huang, Jyh-Jaan; Lin, Sheng-Chi; Löwemark, Ludvig; Liou, Ya-Hsuan; Chang, Queenie; Chang, Tsun-Kuo; Wei, Kuo-Yen; Croudace, Ian W.
2016-04-01
X-ray fluorescence (XRF) core-scanning is a fast, and convenient technique to assess elemental variations for a wide variety of research topics. However, the XRF scanning counts are often considered a semi-quantitative measurement due to possible absorption or scattering caused by down core variability in physical properties. To overcome this problem and extend the applications of XRF-scanning to water pollution studies, we propose to use cation exchange resin (IR-120) as an "elemental carrier", and to analyze the resins using the Itrax-XRF core scanner. The use of resin minimizes the matrix effects during the measurements, and can be employed in the field in great numbers due to its low price. Therefore, the fast, and non-destructive XRF-scanning technique can provide a quick and economical method to analyze environmental pollution via absorption in the resin. Five standard resin samples were scanned by the Itrax-XRF core scanner at different exposure times (1 s, 5 s, 15 s, 30 s, 100 s) to allow the comparisons of scanning counts with the absolute concentrations. The regression lines and correlation coefficients of elements that are generally used in pollution studies (Ca, Ti, Cr, Ni, Cu, Zn, and Pb) were examined for the different exposure times. The result shows that within the test range (from few ppm to thousands ppm), the correlation coefficients are all higher than 0.97, even at the shortest exposure time (1 s). Therefore, we propose to use this method in the field to monitor for example sewage disposal events. The low price of resin, and fast, multi elements and precise XRF-scanning technique provide a viable, cost- and time-effective approach that allows large sample numbers to be processed. In this way, the properties and sources of wastewater pollution can be traced for the purpose of environmental monitoring and environmental forensics.
Barium and calcium analyses in sediment cores using µ-XRF core scanners
NASA Astrophysics Data System (ADS)
Acar, Dursun; Çaǧatay, Namık; Genç, S. Can; Eriş, K. Kadir; Sarı, Erol; Uçarkus, Gülsen
2017-04-01
Barium and Ca are used as proxies for organic productivity in paleooceanographic studies. With its heavy atomic weight (137.33 u), barium is easily detectable in small concentrations (several ppm levels) in marine sediments using XRF methods, including the analysis by µ-XRF core scanners. Calcium has an intermediate atomic weight (40.078 u) but is a major element in the earth's crust and in sediments and sedimentary rocks, and hence it is easily detectable by µ-XRF techniques. Normally, µ-XRF elemental analysis of cores are carried out using split half cores or 1-2 cm thich u-channels with an original moisture. Sediment cores show variation in different water content (and porosity) along their length. This in turn results in variation in the XRF counts of the elements and causes error in the elemental concentrations. We tried µ-XRF elemental analysis of split half cores, subsampled as 1 cm thick u-channels with original moisture and 0.3 mm-thin film slices of the core with original wet sample and after air drying with humidity protector mylar film. We found considerable increase in counts of most elements, and in particular for Ba and Ca, when we used 0.3 mm thin film, dried slice. In the case of Ba, the counts increased about three times that of the analysis made with wet and 1 cm thick u-channels. The higher Ba and Ca counts are mainly due to the possible precipitation of Ba as barite and Ca as gypsum from oxidation of Fe-sulphides and the evaporation of pore waters. The secondary barite and gypsum precipitation would be especially serious in unoxic sediment units, such as sapropels, with considerable Fe-sulphides and bio-barite.It is therefore suggested that reseachers should be cautious of such secondary precipitation on core surfaces when analyzing cores that have long been exposed to the atmospheric conditions.
NASA Astrophysics Data System (ADS)
Höfig, T. W.; LeVay, B.; Stock, J. M.; Sun, Z.; Klaus, A.; Jian, Z.; Larsen, H. C.; Alvarez Zarikian, C. A.
2017-12-01
For three decades, X-ray fluorescence core scanning (XRF-CS) has been widely applied to split sediment cores to obtain continuous data sets of element intensities, serving as chemical proxies for paleoceanography and paleoclimate studies. In contrast, there is no record published on igneous rock cores. This study utilizes a remarkably consistent recovery of lava flows from the South China Sea (SCS), intersected during International Ocean Discovery Program (IODP) Expeditions 367/368, to gain preliminary insights into the chemical inventory of a volcanic suite. At IODP Site U1500, a drilled interval of 150 m, starting at 1379.1 meters below seafloor, yielded 115 m of intercalated fine-grained massive, sheet, and pillow lava flows of basaltic modal composition, consisting of aphyric to highly plagioclase-phyric rocks. The pillow lavas feature numerous well-preserved chilled and glassy margins. The whole succession of lavas is overall slightly to moderately altered and notably fresh in parts. The present XRF data, obtained from a third-generation energy dispersive Avaatech® core scanner at a step size of 2 cm, suggest the existence of two chemically distinct lava suites. The bottom six lava flows (in total 40 m thick) show low intensities of both Cr and Ti (e.g., Ti: 7000-8500 counts), while the upper 11 flows reflect higher concentrations of Cr and Ti (e.g., Ti: 8200-9500 counts). A massive flow, which marks the chemical transition, represents the top of the low-Cr and -Ti lava suite. The compositional change from low-Cr-Ti to high-Cr-Ti lavas reflects a clear temporal magmatic evolution of this submarine SCS volcanism, which is characterized by generally constant Fe/Mn ratios. Thus, this trend may be explained by a change to less fractionated and/or less contaminated lavas over time. On a smaller scale, the XRF-CS also enabled mapping of the compositional variations of crosscutting veins with depth as well as the transition from glassy margins to the micro- to
X-ray Fluorescence Core Scanning of Oman Drilling Project Holes BT1B and GT3A Cores on D/V CHIKYU
NASA Astrophysics Data System (ADS)
Johnson, K. T. M.; Kelemen, P. B.; Michibayashi, K.; Greenberger, R. N.; Koepke, J.; Beinlich, A.; Morishita, T.; Jesus, A. P. M.; Lefay, R.
2017-12-01
The JEOL JSX-3600CA1 energy dispersive X-ray fluorescence core logger (XRF-CL) on the D/V Chikyu provides quantitative element concentrations of scanned cores. Scans of selected intervals are made on an x-y grid with point spacing of 5 mm. Element concentrations for Si, Al, Ti, Ca, Mg, Mn, Fe, Na, K, Cr, Ni, S and Zn are collected for each point on the grid. Accuracy of element concentrations provided by the instrument software is improved by applying empirical correction algorithms. Element concentrations were collected for 9,289 points from twenty-seven core intervals in Hole BT1B (basal thrust) and for 6,389 points from forty core intervals in Hole GT3A (sheeted dike-gabbro transition) of the Oman Drilling Project on the D/V Chikyu XRF-CL during Leg 2 of the Oman Drilling Project in August-September, 2017. The geochemical data are used for evaluating downhole compositional details associated with lithological changes, unit contacts and mineralogical variations and are particularly informative when plotted as concentration contour maps or downhole concentration diagrams. On Leg 2 additional core scans were made with X-ray Computed Tomography (X-ray CT) and infrared images from the visible-shortwave infrared imaging spectroscopy (IR) systems on board. XRF-CL, X-ray CT and IR imaging plots used together provide detailed information on rock compositions, textures and mineralogy that assist naked eye visual observations. Examples of some uses of XRF-CL geochemical maps and downhole data are shown. XRF-CL and IR scans of listvenite clearly show zones of magnesite, dolomite and the Cr-rich mica, fuchsite that are subdued in visual observation, and these scans can be used to calculate variations in proportions of these minerals in Hole BT1B cores. In Hole GT3A XRF-CL data can be used to distinguish compositional changes in different generations of sheeted dikes and gabbros and when combined with visual observations of intrusive relationships the detailed geochemical
NASA Astrophysics Data System (ADS)
Huang, J. J.; Lin, S. C.; Löwemark, L.; Liou, Y. H.; Chang, Q. M.; Chang, T. K.; Wei, K. Y.; Croudace, I. W. C.
2017-12-01
Due to the rapid industrial expansion, environments are subject to irregular fluctuations and spatial distributions in pollutant concentrations. This study proposes to use ion exchange resin accompanied with the XRF-scanning technique to monitor environmental pollution. As a passive sampling sorbent, the use of ion exchange resin provides a rapid, low cost and simple method to detect episodic pollution signals with a high spatial sampling density. In order to digest large quantities of samples, the fast and non-destructive Itrax-XRF core scanner has been introduced to assess elemental concentrations in the resin samples. Although the XRF scanning results are often considered as a semi-quantitative measurement due to possible absorption or scattering caused by the physical variabilities of scanned materials, the use of resin can minimize such influences owing to the standarization of the sample matrix. In this study, 17 lab-prepared standard resin samples were scanned with the Itrax-XRF core scanner (at 100 s exposure time with the Mo-tube) and compared with the absolute elemental concentrations. Six elements generally used in pollution studies (Cr, Mn, Ni, Cu, Zn, and Pb) were selected, and their regression lines and correlation coefficients were determined. In addition, 5 standard resin samples were scanned at different exposure time settings (1 s, 5 s, 15 s, 30 s, 100 s) to address the influence of exposure time on the accuracy of the measurements. The results show that within the test range (from few ppm to thousands ppm), the correlation coefficients are higher than 0.97, even at the shortest exposure time (1 s). Furthermore, a pilot field survey with 30 resin samples has been conducted in a potentially polluted farm area in central Taiwan to demonstrate the feasibility of this novel approach. The polluted hot zones could be identified and the properties and sources of wastewater pollution can therefore be traced over large areas for the purposes of
Fine-resolved XRF geochemistry of bottom fills from Asian lakes
NASA Astrophysics Data System (ADS)
Phedorin (Fedorin), Mikhail
2010-05-01
Over the last fifteen years (1994-2009) several teams from Siberian Branch of Russian Academy of Science have carried out numerous studies of cores of bottom sediments from Asian lakes, to perform regional reconstructions of past climate changes. Within these researches, the method of x-ray fluorescence (XRF) has widely been used to predict downcore distributions of elements; high-resolution XRF scanning of cores has been employed since 1999. Experiments have been performed at XRF facilities of Siberian Synchrotron Center. In this presentation I report (1) ‘know-how's of quantitative processing of experimental fine-scanning XRF data for lacustrine cores, and (2) geochemical signatures of sediments from Asian lakes obtained after XRF fine-scanning of cores. (1) Quantitative prediction of concentrations of elements from fine-scanning XRF data is problematic because of varying water content along scanning profile, as well as due to varying matrix chemistry and sample optical thickness. All these cause varying inter-element influence that changes fluorescence flux through its absorption and/or secondary excitation. To overcome these difficulties we have used an adapted algorithm of fundamental parameters. The mathematical model based on this algorithm accounts for two events of photon/matter interaction. Element concentrations are estimated using reference samples and the internal standard procedure, both with correction of interference effects. The pore water content is inferred from its correlation with the coherent/incoherent scatter intensity ratio. Sediment density is found from water content by a reliable sedimentological law. Normalization to Compton scattering accounts for the irradiated mass of wet sediment controlled by porosity and sampling-related core disturbance. The mathematical model also includes these scattering variations related to lithology, water content, and density of samples. The new method was applied to XRF scans of cores to predict
NASA Astrophysics Data System (ADS)
Rizzi, Malgorzata; Hemmingsen Schovsbo, Niels; Korte, Christoph; Bryld Wessel Fyhn, Michael
2017-04-01
To improve the understanding and interpretation of the depositional environment of a late Oligocene lacustrine organic rich oil-prone source rock succession, 2464 hand held (HH)-XRF measurements were made systematically on the 500 m long, continuous core from the fully cored Enreca-3 well. This core, drilled on the remote Bach Long Vi Island, northern Gulf of Tonkin, offshore Vietnam, represents a deep lake succession alternating between lacustrine pelagic dominated sediments interrupted by hyperpycnal turbidites, high density turbidites and debris flows [1, 2]. From a combined HH-XRF-XRD data set, multivariate data analysis and regression models are used to type the rock and to predict the XRD mineral composition based on HH-XRF composition. The rock types and the modelled mineral composition highlight the geochemical variations of the sediment and allows for direct comparison with sedimentological processes and facies changes. The modeling also depicts the cyclic alteration of rock types that are present on many different scales ranging from centimeters to hundreds of meters [1, 2]. The sedimentological and geochemical variations observed throughout the cored section reflects fluctuating paleoclimate, tectonism and hinterland condition controlling the depositional setting, which may provide a deeper understanding of the deposition of this and similar Paleogene syn-rift succession in the South China Sea region. It allows furthermore the development of a more generalized depositional model relevant for other deep-lacustrine syn-rift basins. [1] Petersen et al. (2014) Journal of Petroleum Geology, 37: 373-389. [2] Hovikoski et al. (2016) Journal of Sedimentary Research, 86(8): 982-1007.
NASA Astrophysics Data System (ADS)
Barrett, Samuel; Tjallingii, Rik; Bloemsma, Menno; Brauer, Achim; Starnberger, Reinhard; Spötl, Christoph; Dulski, Peter
2015-04-01
The outcrop at Baumkirchen (Austria) encloses part of a unique sequence of laminated lacustrine sediments deposited during the last glacial cycle. A ~250m long composite sediment record recovered at this location now continuously covers the periods ~33 to ~45 ka BP (MIS 3) and ~59 to ~73 ka BP (MIS 4), which are separated by a hiatus. The well-laminated (mm-cm scale) and almost entirely clastic sediments reveal alternations of clayey silt and medium silt to very-fine sand layers. Although radiocarbon and optically stimulated luminescence (OSL) dating provide a robust chronology, accurate dating of the sediment laminations appears to be problematic due to very high sedimentation rates (3-8 cm/yr). X-ray fluorescence (XRF) core scanning provided a detailed ~150m long record of compositional changes of the sediments at Baumkirchen. Changes in the sediments are subtle and classification into different facies based on individual elements is therefore subjective. We applied a statistically robust clustering analysis to provide an objective compositional classification without prior knowledge, based on XRF measurements for 15 analysed elements (all those with an acceptable signal-noise ratio: Zr, Sr, Ca, Mn, Cu, Zn, Rb, Ni, Fe, K, Cr, V, Si, Ba, T). The clustering analysis indicates a distinct compositional change between sediments deposited below and above the stratigraphic hiatus, but also differentiates between individual different laminae. Preliminary results suggest variations in the sequence are largely controlled by the relative occurrence of different kinds of sediment represented by different clusters. Three clusters identify well-laminated sediments, visually similar in appearance, each dominated by an anti-correlation between Ca and one or more of the detrital elements K, Zr, Ti, Si and Fe. Two of these clusters occur throughout the entire sequence, one frequently and the other restricted to short sections, while the third occurs almost exclusively below the
NASA Astrophysics Data System (ADS)
Gonzalez, Victor; Calligaro, Thomas; Pichon, Laurent; Wallez, Gilles; Mottin, Bruno
2015-11-01
This work focuses on the composition and microstructure of the lead white pigment employed in a set of paintworks, using a combination of µ-XRD and 2D scanning XRF, directly applied on five drapery studies attributed to Leonardo da Vinci (1452-1519) and conserved in the Département des Arts Graphiques, Musée du Louvre and in the Musée des Beaux- Arts de Rennes. Trace elements present in the composition as well as in the lead white highlights were imaged by 2D scanning XRF. Mineral phases were determined in a fully noninvasive way using a special µ-XRD diffractometer. Phase proportions were estimated by Rietveld refinement. The analytical results obtained will contribute to differentiate lead white qualities and to highlight the artist's technique.
NASA Astrophysics Data System (ADS)
Grunert, Patrick; Balestra, Barbara; Flores, José-Abel; Garcia Gallardo, Ángela; Auer, Gerald; Röhl, Ulla; Piller, Werner E.
2015-04-01
IODP Hole U1389E, at present located in the lower core of the Mediterranean Outflow Water (MOW) at 640m water depth in the northern Gulf of Cadiz, represents a key-site for the understanding of changes in MOW contribution to the North Atlantic during the late Pliocene thermal optimum and the transition into the Pleistocene ice house climate. Zr/Al ratios of the recovered sediments as well as δ18O and Mg/Ca of benthic foraminifera imply major changes in MOW strength in the studied interval. However, to consider these data in a broader paleoceanographic and paleoclimatic context, a well-constrained age model is essential. New data from calcareous nannoplankton and XRF core-scanning suggest that the shipboard age model for the site has to be reconsidered as major changes in sedimentation rates have not been recognized in the original comparably low resolution data-sets. While the new, higher-resolution biostratigraphic data confirm the overall time frame of 2.6 to 3.6 Myrs, they also imply a potential sedimentary hiatus within the Pliocene thermal optimum and a significant increase in sedimentation rates thereafter. A distinct cyclic pattern is recognized in the CaCO3 and TOC contents as well as Ca/Ti ratios. Based on the estimated sedimentation rates these cycles are most likely linked to precessional forcing, resembling cyclic changes in riverine input from southern Spain recognized at several drill-sites at the northern shelf break. A detailed cyclostratigraphic analysis is currently in progress to confirm the precessional signal and to further constrain the duration of the sedimentary hiatus during the Pliocene thermal optimum. This study contributes to project P25831-N29 of the Austrian Science Fund (FWF) and is financially supported by grants of ECORD and the Max Kade Foundation.
Maia Mapper: high definition XRF imaging in the lab
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ryan, Chris G.; Kirkham, R.; Moorhead, G. F.
Here, Maia Mapper is a laboratory μXRF mapping system for efficient elemental imaging of drill core sections serving minerals research and industrial applications. It targets intermediate spatial scales, with imaging of up to ~80 M pixels over a 500×150 mm 2 sample area. It brings together (i) the Maia detector and imaging system, with its large solid-angle, event-mode operation, millisecond pixel transit times in fly-scan mode and real-time spectral deconvolution and imaging, (ii) the high brightness MetalJet D2 liquid metal micro-focus X-ray source from Excillum, and (iii) an efficient XOS polycapillary lens with a flux gain ~15,900 at 21 keVmore » into a ~32 μm focus, and (iv) a sample scanning stage engineered for standard drill-core sections. Count-rates up to ~3 M/s are observed on drill core samples with low dead-time up to ~1.5%. Automated scans are executed in sequence with display of deconvoluted element component images accumulated in real-time in the Maia detector. Application images on drill core and polished rock slabs illustrate Maia Mapper capabilities as part of the analytical workflow of the Advanced Resource Characterisation Facility, which spans spatial dimensions from ore deposit to atomic scales.« less
Maia Mapper: high definition XRF imaging in the lab
Ryan, Chris G.; Kirkham, R.; Moorhead, G. F.; ...
2018-03-13
Here, Maia Mapper is a laboratory μXRF mapping system for efficient elemental imaging of drill core sections serving minerals research and industrial applications. It targets intermediate spatial scales, with imaging of up to ~80 M pixels over a 500×150 mm 2 sample area. It brings together (i) the Maia detector and imaging system, with its large solid-angle, event-mode operation, millisecond pixel transit times in fly-scan mode and real-time spectral deconvolution and imaging, (ii) the high brightness MetalJet D2 liquid metal micro-focus X-ray source from Excillum, and (iii) an efficient XOS polycapillary lens with a flux gain ~15,900 at 21 keVmore » into a ~32 μm focus, and (iv) a sample scanning stage engineered for standard drill-core sections. Count-rates up to ~3 M/s are observed on drill core samples with low dead-time up to ~1.5%. Automated scans are executed in sequence with display of deconvoluted element component images accumulated in real-time in the Maia detector. Application images on drill core and polished rock slabs illustrate Maia Mapper capabilities as part of the analytical workflow of the Advanced Resource Characterisation Facility, which spans spatial dimensions from ore deposit to atomic scales.« less
Maia Mapper: high definition XRF imaging in the lab
NASA Astrophysics Data System (ADS)
Ryan, C. G.; Kirkham, R.; Moorhead, G. F.; Parry, D.; Jensen, M.; Faulks, A.; Hogan, S.; Dunn, P. A.; Dodanwela, R.; Fisher, L. A.; Pearce, M.; Siddons, D. P.; Kuczewski, A.; Lundström, U.; Trolliet, A.; Gao, N.
2018-03-01
Maia Mapper is a laboratory μXRF mapping system for efficient elemental imaging of drill core sections serving minerals research and industrial applications. It targets intermediate spatial scales, with imaging of up to ~80 M pixels over a 500×150 mm2 sample area. It brings together (i) the Maia detector and imaging system, with its large solid-angle, event-mode operation, millisecond pixel transit times in fly-scan mode and real-time spectral deconvolution and imaging, (ii) the high brightness MetalJet D2 liquid metal micro-focus X-ray source from Excillum, and (iii) an efficient XOS polycapillary lens with a flux gain ~15,900 at 21 keV into a ~32 μm focus, and (iv) a sample scanning stage engineered for standard drill-core sections. Count-rates up to ~3 M/s are observed on drill core samples with low dead-time up to ~1.5%. Automated scans are executed in sequence with display of deconvoluted element component images accumulated in real-time in the Maia detector. Application images on drill core and polished rock slabs illustrate Maia Mapper capabilities as part of the analytical workflow of the Advanced Resource Characterisation Facility, which spans spatial dimensions from ore deposit to atomic scales.
NASA Astrophysics Data System (ADS)
Cho, J. H.; Shin, D. H.; Kim, J. K.; Hyun, S.; Jang, S.; Kum, B. C.; Yoo, K. C.; Moh, T. J.
2017-12-01
The cruise of R/V ISABU focused on the detailed geological, geochemical and paleoceanographical investigations in the East Sea. The purpose of this cruise was the use of technically sophisticated Giant Piston Corer (GPC, OSIL) as well as the recovery of the longest piston core (20.7 m, ISA-16ESUB-2B) ever recorded in KIOST with a high resolution of stratigraphic sedimentary layer. The Late Pleistocene to the Holocene sediments in the Ulleung Basin are characterized by several volcanic tephra layers with alternations of fine light and dark clayey layers, reflecting variability in the paleoenvironment. Based on the previous researches and AMS results, we determine the ages of sedimentary layers from three tephra layers, 1.86 mbsf (U-Oki, 10.7 ka), 3.31 mbsf (AT, 29.4 ka), 11.67 mbsf (Aso-4, 88.0 ka) and 17.09 mbsf (Aso-3, 133.0 ka) respectively. Sediment textures are identified as hemipelagic mud, bioturbated mud and laminated mud with tephra layers. The sedimentation rates of each intervals are 0.174 m/kyr (present to U-Oki), 0.078 m/kyr (U-Oki to AT), 0.143 m/kyr (AT to Aso-4) and 0.120 m/kyr (Aso-4 to Aso-3) respectively. Sensitivity of XRF core scanner was obtained by establishing equivalences between peak areas. Element concentrations are analyzed by traditional techniques such as ICP-MS, ICP-OES. The Ca/Fe ratio reflects carbonate content and ISA-16ESUB-2B core shows strong correlation to sedimentary horizons. Sr/Ca ratio has good correlation with sedimentary units. Enhanced Sr contents indicates strong surface ocean production. Br/Cl ratio are high peak during MIS 5.5. Br content implies generally high organic rich sediments.
Computed Tomography Scanning and Geophysical Measurements of Core from the Coldstream 1MH Well
DOE Office of Scientific and Technical Information (OSTI.GOV)
Crandall, Dustin M.; Brown, Sarah; Moore, Johnathan E.
The computed tomography (CT) facilities and the Multi-Sensor Core Logger (MSCL) at the National Energy Technology Laboratory (NETL) Morgantown, West Virginia site were used to characterize core of the Marcellus Shale from a vertical well, the Coldstream 1MH Well in Clearfield County, PA. The core is comprised primarily of the Marcellus Shale from a depth of 7,002 to 7,176 ft. The primary impetus of this work is a collaboration between West Virginia University (WVU) and NETL to characterize core from multiple wells to better understand the structure and variation of the Marcellus and Utica shale formations. As part of thismore » effort, bulk scans of core were obtained from the Coldstream 1MH well, provided by the Energy Corporation of America (now Greylock Energy). This report, and the associated scans, provide detailed datasets not typically available from unconventional shales for analysis. The resultant datasets are presented in this report, and can be accessed from NETL's Energy Data eXchange (EDX) online system using the following link: https://edx.netl.doe.gov/dataset/coldstream-1mh-well. All equipment and techniques used were non-destructive, enabling future examinations to be performed on these cores. None of the equipment used was suitable for direct visualization of the shale pore space, although fractures and discontinuities were detectable with the methods tested. Low resolution CT imagery with the NETL medical CT scanner was performed on the entire core. Qualitative analysis of the medical CT images, coupled with x-ray fluorescence (XRF), P-wave, and magnetic susceptibility measurements from the MSCL were useful in identifying zones of interest for more detailed analysis as well as fractured zones. En echelon fractures were observed at 7,100 ft and were CT scanned using NETL’s industrial CT scanner at higher resolution. The ability to quickly identify key areas for more detailed study with higher resolution will save time and resources in future
A radiographic scanning technique for cores
Hill, G.W.; Dorsey, M.E.; Woods, J.C.; Miller, R.J.
1979-01-01
A radiographic scanning technique (RST) can produce single continuous radiographs of cores or core sections up to 1.5 m long and up to 30 cm wide. Changing a portable industrial X-ray unit from the normal still-shot mode to a scanning mode requires simple, inexpensive, easily constructed, and highly durable equipment. Additional components include a conveyor system, antiscatter cylinder-diaphragm, adjustable sample platform, developing tanks, and a contact printer. Complete cores, half cores, sample slabs or peels may be scanned. Converting the X-ray unit from one mode to another is easy and can be accomplished without the use of special tools. RST provides the investigator with a convenient, continuous, high quality radiograph, saves time and money, and decreases the number of times cores have to be handled. ?? 1979.
NASA Astrophysics Data System (ADS)
Löwemark, L.; Chen, H.-F.; Yang, T.-N.; Kylander, M.; Yu, E.-F.; Hsu, Y.-W.; Lee, T.-Q.; Song, S.-R.; Jarvis, S.
2011-04-01
X-ray fluorescence (XRF) scanning of unlithified, untreated sediment cores is becoming an increasingly common method used to obtain paleoproxy data from lake records. XRF-scanning is fast and delivers high-resolution records of relative variations in the elemental composition of the sediment. However, lake sediments display extreme variations in their organic matter content, which can vary from just a few percent to well over 50%. As XRF scanners are largely insensitive to organic material in the sediment, increasing levels of organic material effectively dilute those components that can be measured, such as the lithogenic material (the closed-sum effect). Consequently, in sediments with large variations in organic material, the measured variations in an element will to a large extent mirror the changes in organic material. It is therefore necessary to normalize the elements in the lithogenic component of the sediment against a conservative element to allow changes in the input of the elements to be addressed. In this study we show that Al, which is the lightest element that can be measured using the Itrax XRF-scanner, can be used to effectively normalize the elements of the lithogenic fraction of the sediment against variations in organic content. We also show that care must be taken when choosing resolution and exposure time to ensure optimal output from the measurements.
Digital Equivalent Data System for XRF Labeling of Objects
NASA Technical Reports Server (NTRS)
Schramm, Harry F.; Kaiser, Bruce
2005-01-01
A digital equivalent data system (DEDS) is a system for identifying objects by means of the x-ray fluorescence (XRF) spectra of labeling elements that are encased in or deposited on the objects. As such, a DEDS is a revolutionary new major subsystem of an XRF system. A DEDS embodies the means for converting the spectral data output of an XRF scanner to an ASCII alphanumeric or barcode label that can be used to identify (or verify the assumed or apparent identity of) an XRF-scanned object. A typical XRF spectrum of interest contains peaks at photon energies associated with specific elements on the Periodic Table (see figure). The height of each spectral peak above the local background spectral intensity is proportional to the relative abundance of the corresponding element. Alphanumeric values are assigned to the relative abundances of the elements. Hence, if an object contained labeling elements in suitably chosen proportions, an alphanumeric representation of the object could be extracted from its XRF spectrum. The mixture of labeling elements and for reading the XRF spectrum would be compatible with one of the labeling conventions now used for bar codes and binary matrix patterns (essentially, two-dimensional bar codes that resemble checkerboards). A further benefit of such compatibility is that it would enable the conversion of the XRF spectral output to a bar or matrix-coded label, if needed. In short, a process previously used only for material composition analysis has been reapplied to the world of identification. This new level of verification is now being used for "authentication."
Identification of New Lithic Clasts in Lunar Breccia 14305 by Micro-CT and Micro-XRF Analysis
NASA Technical Reports Server (NTRS)
Zeigler, Ryan A.; Carpenter, Paul K.; Jolliff, Bradley L.
2014-01-01
From 1969 to 1972, Apollo astronauts collected 382 kg of rocks, soils, and core samples from six locations on the surface of the Moon. The samples were initially characterized, largely by binocular examination, in a custom-built facility at Johnson Space Center (JSC), and the samples have been curated at JSC ever since. Despite over 40 years of study, demand for samples remains high (500 subsamples per year are allocated to scientists around the world), particularly for plutonic (e.g., anorthosites, norites, etc.) and evolved (e.g., granites, KREEP basalts) lithologies. The reason for the prolonged interest is that as new scientists and new techniques examine the samples, our understanding of how the Moon, Earth, and other inner Solar System bodies formed and evolved continues to grow. Scientists continually clamor for new samples to test their emerging hypotheses. Although all of the large Apollo samples that are igneous rocks have been classified, many Apollo samples are complex polymict breccias that have previously yielded large (cm-sized) igneous clasts. In this work we present the initial efforts to use the non-destructive techniques of micro-computed tomography (micro-CT) and micro x-ray fluorescence (micro-XRF) to identify large lithic clasts in Apollo 14 polymict breccia sample 14305. The sample in this study is 14305,483, a 150 g slab of regolith breccia 14305 measuring 10x6x2 cm (Figure 1a). The sample was scanned at the University of Texas High-Resolution X-ray CT Facility on an Xradia MicroXCT scanner. Two adjacent overlapping volumes were acquired at 49.2 micrometer resolution and stitched together, resulting in 1766 slices. Each volume was acquired at 100 kV accelerating voltage and 98 mA beam current with a 1 mm CaF2 filter, with 2161 views gathered over 360deg at 3 seconds acquisition time per view. Micro-XRF analyses were done at Washington University in St. Louis, Missouri on an EDAX Orbis PC micro-XRF instrument. Multiple scans were made at 40 k
Pendleton, Michael W; Washburn, Dorothy K; Ellis, E Ann; Pendleton, Bonnie B
2014-03-01
The same sherd was analyzed using a scanning electron microscope with energy dispersive spectroscopy (SEM-EDS) and a micro X-ray fluorescence tube attached to a scanning electron microscope (Micro-XRF-SEM) to compare the effectiveness of elemental detection of iron-based pigment. To enhance SEM-EDS mapping, the sherd was carbon coated. The carbon coating was not required to produce Micro-XRF-SEM maps but was applied to maintain an unbiased comparison between the systems. The Micro-XRF-SEM analysis was capable of lower limits of detection than that of the SEM-EDS system, and therefore the Micro-XRF-SEM system could produce elemental maps of elements not easily detected by SEM-EDS mapping systems. Because SEM-EDS and Micro-XRF-SEM have been used for imaging and chemical analysis of biological samples, this comparison of the detection systems should be useful to biologists, especially those involved in bone or tooth (hard tissue) analysis.
Pendleton, Michael W.; Washburn, Dorothy K.; Ellis, E. Ann; Pendleton, Bonnie B.
2014-01-01
The same sherd was analyzed using a scanning electron microscope with energy dispersive spectroscopy (SEM-EDS) and a micro X-ray fluorescence tube attached to a scanning electron microscope (Micro-XRF-SEM) to compare the effectiveness of elemental detection of iron-based pigment. To enhance SEM-EDS mapping, the sherd was carbon coated. The carbon coating was not required to produce Micro-XRF-SEM maps but was applied to maintain an unbiased comparison between the systems. The Micro-XRF-SEM analysis was capable of lower limits of detection than that of the SEM-EDS system, and therefore the Micro-XRF-SEM system could produce elemental maps of elements not easily detected by SEM-EDS mapping systems. Because SEM-EDS and Micro-XRF-SEM have been used for imaging and chemical analysis of biological samples, this comparison of the detection systems should be useful to biologists, especially those involved in bone or tooth (hard tissue) analysis. PMID:24600333
Development of a versatile XRF scanner for the elemental imaging of paintworks
NASA Astrophysics Data System (ADS)
Ravaud, E.; Pichon, L.; Laval, E.; Gonzalez, V.; Eveno, M.; Calligaro, T.
2016-01-01
Scanning XRF is a powerful elemental imaging technique introduced at the synchrotron that has recently been transposed to laboratory. The growing interest in this technique stems from its ability to collect images reflecting pigment distribution within large areas on artworks by means of their elemental signature. In that sense, scanning XRF appears highly complementary to standard imaging techniques (Visible, UV, IR photography and X-ray radiography). The versatile XRF scanner presented here has been designed and built at the C2RMF in response to specific constraints: transportability, cost-effectiveness and ability to scan large areas within a single working day. The instrument is based on a standard X-ray generator with sub-millimetre collimated beam and a SDD-based spectrometer to collected X-ray spectra. The instrument head is scanned in front of the painting by means of motorised movements to cover an area up to 300 × 300 mm2 with a resolution of 0.5 mm (600 × 600 pixels). The 15-kg head is mounted on a stable photo stand for rapid positioning on paintworks and maintains a free side-access for safety; it can also be attached to a lighter tripod for field measurements. Alignment is achieved with a laser pointer and a micro-camera. With a scanning speed of 5 mm/s and 0.1 s/point, elemental maps are collected in 10 h, i.e. a working day. The X-ray spectra of all pixels are rapidly processed using an open source program to derive elemental maps. To illustrate the capabilities of this instrument, this contribution presents the results obtained on the Belle Ferronnière painted by Leonardo da Vinci (1452-1519) and conserved in the Musée du Louvre, prior to its restoration at the C2RMF.
NASA Astrophysics Data System (ADS)
Tian, J.; Xie, X.; Jin, H.; Wang, P.; Jian, Z.
2009-12-01
Energy dispersive X-ray fluorescence (XRF) scanning technology provides the most accurate and most economic analytical methods for the determination of major and minor elements of the deep-sea sediment ranging from sodium (11) to uranium (92). Scanning on the smooth core surface by XRF Core scanner is reliable and non-destructive to the sediment, requiring little or no time to prepare the core. This method overcomes the drawback of the traditional analytical method by ICP-AES or ICP-MS which requires long time for sample preparation. Thus, it makes it viable to reconstruct long and high-resolution elemental time series from sediment cores. We have performed relatively elemental concentration analyses on the deep sea sediment cores from ODP site 1143 (southern SCS) down to 190.77 mcd (meters composite depth) by XRF core scanner. The depth resolution of the scanning is 1 cm, equivalent to a time resolution of ~250 years. The age model is based on tuning the benthic foraminiferal d18O at Site 1143 to obliquity and precession (Tian et al., 2002) which indicates that the 190.77 meters long sediment spans the past 5 Myr. We compared the records between 99.5 and 136.46 mcd with the elemental records from the same site obtained by Philips PW 2400 X-ray spectrometer (Wehausen et al., online publication). Comparison reveals, regardless of the absolute changes of the elements, that the elemental records (Si, Ti, Al, Fe, Mn, Ca, K, P, Ba, Rb, Sr) obtained by two methods are nearly the same. Results show that the relative concentration variations of the productivity related elements such as Ba and Ca display distinctive glacial-interglacial cycles for the past 5 Myr. These productivity cycles recorded show one-on-one relationship with the glacial-interglacial cycles of the global ice volume change recorded in the benthic foraminiferal d18O. The glacial-interglacial cycles in productivity and global ice volume changes are consistent with each other not only in amplitude but also
Microbialite Biosignature Analysis by Mesoscale X-ray Fluorescence (μXRF) Mapping
NASA Astrophysics Data System (ADS)
Tice, Michael M.; Quezergue, Kimbra; Pope, Michael C.
2017-11-01
As part of its biosignature detection package, the Mars 2020 rover will carry PIXL, the Planetary Instrument for X-ray Lithochemistry, a spatially resolved X-ray fluorescence (μXRF) spectrometer. Understanding the types of biosignatures detectable by μXRF and the rock types μXRF is most effective at analyzing is therefore an important goal in preparation for in situ Mars 2020 science and sample selection. We tested mesoscale chemical mapping for biosignature interpretation in microbialites. In particular, we used μXRF to identify spatial distributions and associations between various elements ("fluorescence microfacies") to infer the physical, biological, and chemical processes that produced the observed compositional distributions. As a test case, elemental distributions from μXRF scans of stromatolites from the Mesoarchean Nsuze Group (2.98 Ga) were analyzed. We included five fluorescence microfacies: laminated dolostone, laminated chert, clotted dolostone and chert, stromatolite clast breccia, and cavity fill. Laminated dolostone was formed primarily by microbial mats that trapped and bound loose sediment and likely precipitated carbonate mud at a shallow depth below the mat surface. Laminated chert was produced by the secondary silicification of microbial mats. Clotted dolostone and chert grew as cauliform, cryptically laminated mounds similar to younger thrombolites and was likely formed by a combination of mat growth and patchy precipitation of early-formed carbonate. Stromatolite clast breccias formed as lag deposits filling erosional scours and interstromatolite spaces. Cavities were filled by microquartz, Mn-rich dolomite, and partially dolomitized calcite. Overall, we concluded that μXRF is effective for inferring genetic processes and identifying biosignatures in compositionally heterogeneous rocks.
PIXE and XRF Analysis of Roman Denarii
NASA Astrophysics Data System (ADS)
Fasano, Cecilia; Raddell, Mark; Manukyan, Khachatur; Stech, Edward; Wiescher, Michael
2017-09-01
A set of Roman Denarii from the republican to the imperial period (140BC-240AD) has been studied using X-ray fluorescent (XRF) scanning and proton induced x-ray emission (PIXE) techniques. XRF and PIXE are commonly used in the study of cultural heritage objects because they are nondestructive. The combination of these two methods is also unique because of the ability to penetrate the sample with a broader spectrum of depths and energies than either could achieve on its own. The coins are from a large span of Roman history and their analysis serves to follow the economic and political change of the era using the relative silver and copper contents in each sample. In addition to analyzing the samples, the study sought to compare these two common analysis techniques and to explore the use of a standard to examine any shortcomings in either of the methods. Data sets were compared and then adjusted to a calibration curve which was created from the analysis of a number of standard solutions. The concentrations of the standard solutions were confirmed using inductively coupled plasma spectroscopy. Through this we were able to assemble results which will progress the basis of understanding of PIXE and XRF techniques as well as increase the wealth of knowledge of Ancient Roman currency.
NASA Astrophysics Data System (ADS)
Lyle, M. W.; Stepanova, A.; Wilson, J. K.; Marcantonio, F.
2014-12-01
The equatorial Pacific is the largest open ocean productivity center, responsible for nearly half of global marine new production and about 40% of CaCO3 burial. Understanding how the equatorial Pacific upwelling system has evolved over the Neogene is critical to understand the evolution of the global carbon cycle. We know from reconnaissance studies that productivity in equatorial Pacific surface waters as well as dissolution driven by deep waters have strongly affected the sediment record. We have used calibrated XRF scanning to capture anomalies in equatorial Pacific upwelling and productivity at Milankovitch-resolving resolution since the early Miocene. The 8 elements calibrated in the XRF scans can be used to distinguish intervals of high carbonate dissolution from those of high productivity. Carbonate dissolution intervals are recorded by a drop of CaCO3 relative to Aeolian clays, with little change in the ratio between estimated opal and clay (estimated by TiO2). In contrast, high production intervals have high opal/TiO2 and low CaCO3. Low CaCO3 contents are caused partly by dilution, since high production skews tropical particulate rain to be more opal-rich relative to carbonate, and additional C-org rain can help to increase CaCO3 dissolution within near-surface sediments. We observe long-lived high production anomalies modulated by orbitally-driven climate variability. Prominent intervals are found at the end of the Miocene climate optimum (~ 14 Ma), interspersed with dissolution intervals in the Carbonate Crash interval (~9-11 Ma), and in the Biogenic Bloom interval (8-4.5 Ma). Using relationships among biogenic fluxes in modern equatorial sediment trap studies, especially the positive correlations between biogenic Ba , C-org, and CaCO3 fluxes, we find that the highest production intervals have much higher opal/C-org in the particulate rain, implying an inefficient carbon pump to the deep ocean. If confirmed, productivity was not as strong a feedback to
Microbialite Biosignature Analysis by Mesoscale X-ray Fluorescence (μXRF) Mapping.
Tice, Michael M; Quezergue, Kimbra; Pope, Michael C
2017-11-01
As part of its biosignature detection package, the Mars 2020 rover will carry PIXL, the Planetary Instrument for X-ray Lithochemistry, a spatially resolved X-ray fluorescence (μXRF) spectrometer. Understanding the types of biosignatures detectable by μXRF and the rock types μXRF is most effective at analyzing is therefore an important goal in preparation for in situ Mars 2020 science and sample selection. We tested mesoscale chemical mapping for biosignature interpretation in microbialites. In particular, we used μXRF to identify spatial distributions and associations between various elements ("fluorescence microfacies") to infer the physical, biological, and chemical processes that produced the observed compositional distributions. As a test case, elemental distributions from μXRF scans of stromatolites from the Mesoarchean Nsuze Group (2.98 Ga) were analyzed. We included five fluorescence microfacies: laminated dolostone, laminated chert, clotted dolostone and chert, stromatolite clast breccia, and cavity fill. Laminated dolostone was formed primarily by microbial mats that trapped and bound loose sediment and likely precipitated carbonate mud at a shallow depth below the mat surface. Laminated chert was produced by the secondary silicification of microbial mats. Clotted dolostone and chert grew as cauliform, cryptically laminated mounds similar to younger thrombolites and was likely formed by a combination of mat growth and patchy precipitation of early-formed carbonate. Stromatolite clast breccias formed as lag deposits filling erosional scours and interstromatolite spaces. Cavities were filled by microquartz, Mn-rich dolomite, and partially dolomitized calcite. Overall, we concluded that μXRF is effective for inferring genetic processes and identifying biosignatures in compositionally heterogeneous rocks. Key Words: Stromatolites-Biosignatures-Spectroscopy-Archean. Astrobiology 17, 1161-1172.
NASA Astrophysics Data System (ADS)
Reilly, B. T.; Stoner, J. S.; Mix, A. C.; Jakobsson, M.; Jennings, A. E.; Walczak, M.; Dyke, L. M.; Cheseby, M.; Albert, S. W.; Wiest, J.
2016-12-01
An international and interdisciplinary expedition to Nares Strait and Petermann Fjord, Northwest Greenland, onboard the Swedish Icebreaker Oden July-September 2015 (OD1507) sought to understand the Holocene history of the Petermann glacial system among other research objectives. Petermann Glacier, which terminates as a floating ice-tongue in Petermann Fjord, is thought to be especially sensitive to ice-ocean interactions. While limited historical observations dating back to 1876 suggest the Petermann Ice Tongue extends about 70-90 km from the grounding-line, large calving events in 2010 and 2012 reduced the ice-tongue extent to about 45 km from the grounding-line. A suite of 14 marine sediment cores recovered a range of glacio-marine facies that form an along fjord (15-80 km from the grounding-line) and an across fjord depth (473-1041 meters water depth) transect. CT scans clearly identify four primary fjord facies, including bioturbated, IRD-rich, laminated and mud with stratified graded sand layers. The latter of these occurs near the modern grounding-line. Additionally, a new MATLAB routine is used to quantify clasts >2 mm in size from the CT scans. XRF sediment geochemical changes mirror magnetic mineral concentrations and are driven by varying contribution of Ca-rich and Ca-poor sources, which we interpret as a reflection of the mixing of the local carbonate rocks and crystalline basement excavated by the ice sheet. Initial paleomagnetic results isolate a strong and stable characteristic remanent magnetization which show remarkable similarity to paleosecular variation (PSV) recorded in nearby mid-late Holocene varved lakes on Ellesmere Island. This non-destructive dataset provides robust correlations, indicating a coherent and dynamic record of changes in the Petermann glacial system during the late Holocene, including evidence for a significant grounding-line retreat followed by the growth and relative paleo-extent of the modern Petermann Ice Tongue.
Influence of depositional environment in fossil teeth: a micro-XRF and XAFS study
NASA Astrophysics Data System (ADS)
Zougrou, I. M.; Katsikini, M.; Pinakidou, F.; Papadopoulou, L.; Tsoukala, E.; Paloura, E. C.
2014-04-01
The formation of metal-rich phases during the fossilization of vertebrate fossil teeth, recovered from various deposition environments in northern Greece, is studied by means of synchrotron radiation X-ray fluorescence (SR-XRF) as well as Fe and Mn K edge X-ray absorption fine structure (XAFS) spectroscopy. XRF line-scans from the samples' cross-sections revealed different contamination paths for Mn and Fe. The two-dimensional XRF maps illustrate the spatial distribution of P, Ca, Mn and Fe as well as the precipitation of Fe-rich phases in cementum, dentin and dentinal tubules. Goethite, lepidocrocite and ferrihydrite were detected in the samples' cross-section by means of Fe K edge EXAFS spectroscopy. Moreover the Fe and Mn K edge EXAFS revealed the presence of vivianite and birnessite (MnO2) on the external surface of two samples.
INNOVATIVE TECHNOLOGY VERIFICATION REPORT XRF ...
The Niton XLt 700 Series (XLt) XRF Services x-ray fluorescence (XRF) analyzer was demonstrated under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program. The field portion of the demonstration was conducted in January 2005 at the Kennedy Athletic, Recreational and Social Park (KARS) at Kennedy Space Center on Merritt Island, Florida. The demonstration was designed to collect reliable performance and cost data for the XLt analyzer and seven other commercially available XRF instruments for measuring trace elements in soil and sediment. The performance and cost data were evaluated to document the relative performance of each XRF instrument. This innovative technology verification report describes the objectives and the results of that evaluation and serves to verify the performance and cost of the XLt analyzer. Separate reports have been prepared for the other XRF instruments that were evaluated as part of the demonstration. The objectives of the evaluation included determining each XRF instrument’s accuracy, precision, sample throughput, and tendency for matrix effects. To fulfill these objectives, the field demonstration incorporated the analysis of 326 prepared samples of soil and sediment that contained 13 target elements. The prepared samples included blends of environmental samples from nine different sample collection sites as well as spiked samples with certified element concentrations. Accuracy
INNOVATIVE TECHNOLOGY VERIFICATION REPORT XRF ...
The Rigaku ZSX Mini II (ZSX Mini II) XRF Services x-ray fluorescence (XRF) analyzer was demon-strated under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program. The field portion of the demonstration was conducted in January 2005 at the Kennedy Athletic, Recreational and Social Park (KARS) at Kennedy Space Center on Merritt Island, Florida. The demonstration was designed to collect reliable performance and cost data for the ZSX Mini II analyzer and seven other commercially available XRF instruments for measuring trace elements in soil and sediment. The performance and cost data were evaluated to document the relative performance of each XRF instrument. This innovative technology verification report describes the objectives and the results of that evaluation and serves to verify the performance and cost of the ZSX Mini II analyzer. Separate reports have been prepared for the other XRF instruments that were evaluated as part of the demonstration. The objectives of the evaluation included determining each XRF instrument’s accuracy, precision, sample throughput, and tendency for matrix effects. To fulfill these objectives, the field demonstration incorporated the analysis of 326 prepared samples of soil and sediment that contained 13 target elements. The prepared samples included blends of environmental samples from nine different sample collection sites as well as spiked samples with certified element con
INNOVATIVE TECHNOLOGY VERIFICATION REPORT XRF ...
The Elvatech, Ltd. ElvaX (ElvaX) x-ray fluorescence (XRF) analyzer distributed in the United States by Xcalibur XRF Services (Xcalibur), was demonstrated under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program. The field portion of the demonstration was conducted in January 2005 at the Kennedy Athletic, Recreational and Social Park (KARS) at Kennedy Space Center on Merritt Island, Florida. The demonstration was designed to collect reliable performance and cost data for the ElvaX analyzer and seven other commercially available XRF instruments for measuring trace elements in soil and sediment. The performance and cost data were evaluated to document the relative performance of each XRF instrument. This innovative technology verification report describes the objectives and the results of that evaluation and serves to verify the performance and cost of the ElvaX analyzer. Separate reports have been prepared for the other XRF instruments that were evaluated as part of the demonstration. The objectives of the evaluation included determining each XRF instrument’s accuracy, precision, sample throughput, and tendency for matrix effects. To fulfill these objectives, the field demonstration incorporated the analysis of 326 prepared samples of soil and sediment that contained 13 target elements. The prepared samples included blends of environmental samples from nine different sample collection sites as well as s
INNOVATIVE TECHNOLOGY VERIFICATION REPORT XRF ...
The Rontec PicoTAX x-ray fluorescence (XRF) analyzer was demonstrated under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program. The field portion of the demonstration was conducted in January 2005 at the Kennedy Athletic, Recreational and Social Park (KARS) at Kennedy Space Center on Merritt Island, Florida. The demonstration was designed to collect reliable performance and cost data for the PicoTAX analyzer and seven other commercially available XRF instruments for measuring trace elements in soil and sediment. The performance and cost data were evaluated to document the relative performance of each XRF instrument. This innovative technology verification report describes the objectives and the results of that evaluation and serves to verify the performance and cost of the PicoTAX analyzer. Separate reports have been prepared for the other XRF instruments that were evaluated as part of the demonstration. The objectives of the evaluation included determining each XRF instrument’s accuracy, precision, sample throughput, and tendency for matrix effects. To fulfill these objectives, the field demonstration incorporated the analysis of 326 prepared samples of soil and sediment that contained 13 target elements. The prepared samples included blends of environmental samples from nine different sample collection sites as well as spiked samples with certified element concentrations. Accuracy was assessed by c
INNOVATIVE TECHNOLOGY VERIFICATION REPORT XRF ...
The Oxford ED2000 x-ray fluorescence (XRF) analyzer was demonstrated under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program. The field portion of the demonstration was conducted in January 2005 at the Kennedy Athletic, Recreational and Social Park (KARS) at Kennedy Space Center on Merritt Island, Florida. The demonstration was designed to collect reliable performance and cost data for the ED2000 analyzer and seven other commercially available XRF instruments for measuring trace elements in soil and sediment. The performance and cost data were evaluated to document the relative performance of each XRF instrument. This innovative technology verification report describes the objectives and the results of that evaluation and serves to verify the performance and cost of the ED2000 analyzer. Separate reports have been prepared for the other XRF instruments that were evaluated as part of the demonstration. The objectives of the evaluation included determining each XRF instrument’s accuracy, precision, sample throughput, and tendency for matrix effects. To fulfill these objectives, the field demonstration incorporated the analysis of 326 prepared samples of soil and sediment that contained 13 target elements. The prepared samples included blends of environmental samples from nine different sample collection sites as well as spiked samples with certified element concentrations. Accuracy was assessed by com
INNOVATIVE TECHNOLOGY VERIFICATION REPORT XRF ...
The Innov-X XT400 Series (XT400) x-ray fluorescence (XRF) analyzer was demonstrated under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program. The field portion of the demonstration was conducted in January 2005 at the Kennedy Athletic, Recreational and Social Park (KARS) at Kennedy Space Center on Merritt Island, Florida. The demonstration was designed to collect reliable performance and cost data for the XT400 analyzer and seven other commercially available XRF instruments for measuring trace elements in soil and sediment. The performance and cost data were evaluated to document the relative performance of each XRF instrument. This innovative technology verification report describes the objectives and the results of that evaluation and serves to verify the performance and cost of the XT400 analyzer. Separate reports have been prepared for the other XRF instruments that were evaluated as part of the demonstration. The objectives of the evaluation included determining each XRF instrument’s accuracy, precision, sample throughput, and tendency for matrix effects. To fulfill these objectives, the field demonstration incorporated the analysis of 326 prepared samples of soil and sediment that contained 13 target elements. The prepared samples included blends of environmental samples from nine different sample collection sites as well as spiked samples with certified element concentrations. Accuracy was as
Investigation of gunshot residue patterns using milli-XRF-techniques: first experiences in casework
NASA Astrophysics Data System (ADS)
Schumacher, Rüdiger; Barth, Martin; Neimke, Dieter; Niewöhner, Ludwig
2010-06-01
The investigation of gunshot residue (GSR) patterns for shooting range estimation is usually based on visualizing the lead, copper, or nitrocellulose distributions on targets like fabric or adhesive tape by chemographic color tests. The method usually provides good results but has its drawbacks when it comes to the examination of ammunition containing lead-free primers or bloody clothing. A milli-X-ray fluorescence (m-XRF) spectrometer with a large motorized stage can help to circumvent these problems allowing the acquisition of XRF mappings of relatively large areas (up to 20 x 20 cm) in millimeter resolution within reasonable time (2-10 hours) for almost all elements. First experiences in GSR casework at the Forensic Science Institute of the Bundeskriminalamt (BKA) have shown, that m-XRF is a useful supplementation for conventional methods in shooting ranges estimation, which helps if there are problems in transferring a GSR pattern to secondary targets (e.g. bloody or stained garments) or if there is no suitable color test available for the element of interest. The resulting elemental distributions are a good estimate for the shooting range and can be evaluated by calculating radial distributions or integrated count rates of irregular shaped regions like pieces of human skin which are too small to be investigated with a conventional WD-XRF spectrometer. Beside a mapping mode the milli-XRF offers also point and line scan modes which can also be utilized in gunshot crime investigations as a quick survey tool to identify bullet holes based on the elements present in the wipe ring.
Application of GEM-based detectors in full-field XRF imaging
NASA Astrophysics Data System (ADS)
Dąbrowski, W.; Fiutowski, T.; Frączek, P.; Koperny, S.; Lankosz, M.; Mendys, A.; Mindur, B.; Świentek, K.; Wiącek, P.; Wróbel, P. M.
2016-12-01
X-ray fluorescence spectroscopy (XRF) is a commonly used technique for non-destructive elemental analysis of cultural heritage objects. It can be applied to investigations of provenance of historical objects as well as to studies of art techniques. While the XRF analysis can be easily performed locally using standard available equipment there is a growing interest in imaging of spatial distribution of specific elements. Spatial imaging of elemental distrbutions is usually realised by scanning an object with a narrow focused X-ray excitation beam and measuring characteristic fluorescence radiation using a high energy resolution detector, usually a silicon drift detector. Such a technique, called macro-XRF imaging, is suitable for investigation of flat surfaces but it is time consuming because the spatial resolution is basically determined by the spot size of the beam. Another approach is the full-field XRF, which is based on simultaneous irradiation and imaging of large area of an object. The image of the investigated area is projected by a pinhole camera on a position-sensitive and energy dispersive detector. The infinite depth of field of the pinhole camera allows one, in principle, investigation of non-flat surfaces. One of possible detectors to be employed in full-field XRF imaging is a GEM based detector with 2-dimensional readout. In the paper we report on development of an imaging system equipped with a standard 3-stage GEM detector of 10 × 10 cm2 equipped with readout electronics based on dedicated full-custom ASICs and DAQ system. With a demonstrator system we have obtained 2-D spatial resolution of the order of 100 μm and energy resolution at a level of 20% FWHM for 5.9 keV . Limitations of such a detector due to copper fluorescence radiation excited in the copper-clad drift electrode and GEM foils is discussed and performance of the detector using chromium-clad electrodes is reported.
Laboratory-based characterization of plutonium in soil particles using micro-XRF and 3D confocal XRF
McIntosh, Kathryn Gallagher; Cordes, Nikolaus Lynn; Patterson, Brian M.; ...
2015-03-29
The investigation of plutonium (Pu) in a soil matrix is of interest in safeguards, nuclear forensics, and environmental remediation activities. The elemental composition of two plutonium contaminated soil particles was characterized nondestructively using a pair of micro X-ray fluorescence spectrometry (micro-XRF) techniques including high resolution X-ray (hiRX) and 3D confocal XRF. The three dimensional elemental imaging capability of confocal XRF permitted the identification two distinct Pu particles within the samples: one external to the Ferich soil matrix and another co-located with Cu within the soil matrix. The size and morphology of the particles was assessed with X-ray transmission microscopy andmore » micro X-ray computed tomography (micro-CT) providing complementary morphological information. Limits of detection for a 30 μm Pu particle are <10 ng for each of the XRF techniques. Ultimately, this study highlights the capability for lab-based, nondestructive, spatially resolved characterization of heterogeneous matrices on the micrometer scale with nanogram sensitivity.« less
Vacuum Attachment for XRF Scanner
NASA Technical Reports Server (NTRS)
Schramm, Harry F.; Kaiser, Bruce
2005-01-01
Vacuum apparatuses have been developed for increasing the range of elements that can be identified by use of x-ray fluorescent (XRF) scanners of the type mentioned in the two immediately preceding articles. As a consequence of the underlying physical principles, in the presence of air, such an XRF scanner is limited to analysis of chlorine and elements of greater atomic number. When the XRF scanner is operated in a vacuum, it extends the range of analysis to lower atomic numbers - even as far as aluminum and sodium. Hence, more elements will be available for use in XRF labeling of objects as discussed in the two preceding articles. The added benefits of the extended capabilities also have other uses for NASA. Detection of elements of low atomic number is of high interest to the aerospace community. High-strength aluminum alloys will be easily analyzed for composition. Silicon, a major contaminant in certain processes, will be detectable before the process is begun, possibly eliminating weld or adhesion problems. Exotic alloys will be evaluated for composition prior to being placed in service where lives depend on them. And in the less glamorous applications, such as bolts and fasteners, substandard products and counterfeit items will be evaluated at the receiving function and never allowed to enter the operation
XRF Experiment for Elementary Surface Analysis
NASA Astrophysics Data System (ADS)
Köhler, E.; Dreißigacker, A.; Fabel, O.; van Gasselt, S.; Meyer, M.
2014-04-01
The proposed X-Ray Fluorescence Instrument Package (XRF-X and XRF-E) is being designed to quantitatively measure the composition and map the distribution of rock-surface materials in order to support the target area selection process for exploration, sampling, and mining. While energydispersive X-Ray fluorescence (EDX) makes use of Solar X-Rays for excitation to probe materials over arbitrary distances (by XRF-X), electron-beam excitation can be used for proximity measurements (by XRF-E) over short-distance of up to about 10 - 20m. This design is targeted at observing and analyzing surface compositions from orbital platforms and it is in particular applicable to all atmosphereless solidsurface bodies. While the instrument design for observing objects in the outer solar system is challenging due to low count rates, the Moon and objects of the asteroid belt usually receive solar X-ray radiation that allows to integrate a statistically reliable data basis. Asteroids are attractive targets and have been visited using X-ray fluorescence instruments by orbiting spacecraft in the past (Itokawa, Eros). They are wellaccessible objects for determining elemental compositions and assessing potential mineral resources.
The Niton XLt 700 Series (XLt) XRF Services x-ray fluorescence (XRF) analyzer was demonstrated under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program. The field portion of the demonstration was conducted in January 2005 at ...
The Rigaku ZSX Mini II (ZSX Mini II) XRF Services x-ray fluorescence (XRF) analyzer was demon-strated under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program. The field portion of the demonstration was conducted in January 2...
A 3,000-year quantitative drought record derived from XRF element data from a south Texas playa
NASA Astrophysics Data System (ADS)
Livsey, D. N.; Simms, A.; Hangsterfer, A.; Nisbet, R.; DeWitt, R.
2013-12-01
Recent droughts throughout the central United States highlight the need for a better understanding of the past frequency and severity of drought occurrence. Current records of past drought for the south Texas coast are derived from tree-ring data that span approximately the last 900 years before present (BP). In this study we utilize a supervised learning routine to create a transfer function between X-Ray Fluorescence (XRF) derived elemental data from Laguna Salada, Texas core LS10-02 to a locally derived tree-ring drought record. From this transfer function the 900 BP tree-ring drought record was extended to 3,000 BP. The supervised learning routine was trained on the first 100 years of XRF element data and tree-ring drought data to create the transfer function and training data set output. The model was then projected from the XRF elemental data for the next 800 years to create a deployed data set output and to test the transfer function parameters. The coefficients of determination between the model output and observed values are 0.77 and 0.70 for the 100-year training data set and 900-year deployed data set respectively. Given the relatively high coefficients of determination for both the training data set and deployed data set we interpret the model parameters are fairly robust and that a high-resolution drought record can be derived from the XRF element data. These results indicate that XRF element data can be used as a quantitative tool to reconstruct past drought records.
NASA Astrophysics Data System (ADS)
Ma, C.-J.; Tohno, S.; Kasahara, M.; Hayakawa, S.
2004-06-01
To determine the chemical properties of residue retained in individual cloud droplets is primarily important for the understanding of rainout mechanism and aerosol modification in droplet. The sampling of individual cloud droplets were carried out on the summit of Mt. Taiko located in Tango peninsula, Kyoto prefecture, during Asian dust storm event in March of 2002. XRF microprobe system equipped at SPring-8, BL-37XU was applied to the subsequent quantification analysis of ultra trace elements in residues of individual cloud droplets. It was possible to form the replicas of separated individual cloud droplets on the thin collodion film. The two dimensional XRF maps for the residues in individual cloud droplets were clearly drawn by scanning of micro-beam. Also, XRF spectra of trace elements in residues were well resolved. From the XRF spectra for individual residues, the chemical mixed state of residues could be assumed. The chemical forms of Fe (Fe +++) and Zn (Zn +) could be clearly characterized by their K-edge micro-XANES spectra. By comparison of Z/Si mass ratios of residues in cloud droplets and those of the original sands collected in desert areas in China, the aging of ambient dust particles and their in cloud modification were indirectly assumed.
The Elvatech, Ltd. ElvaX (ElvaX) x-ray fluorescence (XRF) analyzer distributed in the United States by Xcalibur XRF Services (Xcalibur), was demonstrated under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program. The field por...
Composition and microstructure of MTA and Aureoseal Plus: XRF, EDS, XRD and FESEM evaluation.
Cianconi, L; Palopoli, P; Campanella, V; Mancini, M
2016-12-01
The aim of this study was to determine the chemical composition and the phases' microstructure of Aureoseal Plus (OGNA, Italy) and ProRoot MTA (Dentsply Tulsa Dental, USA) and to compare their characteristics. Study Design: Comparing Aureoseal Plus and ProRoot MTA microstructure by means of several analyses type. The chemical analysis of the two cements was assessed following the UNI EN ISO 196-2 norm. X-Ray fluorescence (XRF) was used to determine the element composition. The crystalline structure was analysed quantitatively using x-ray diffraction (XRD). Powders morphology was evaluated using a scanning electron microscope (SEM) with backscattering detectors, and a field emission scanning electron microscope (FESEM). Elemental analysis was performed by energy dispersive x-ray analysis (EDS). The semi-quantitative XRF analysis showed the presence of heavy metal oxides in both cements. The XRD spectra of the two cements reported the presence of dicalcium silicate, tricalcium silicate, tricalcium aluminate, tetracalcium aluminoferrite, bismuth oxide and gypsum. SEM analysis showed that ProRoot MTA powder is less coarse and more homogeneous than Aureoseal. Both powders are formed by particles of different shapes: round, prismatic and oblong. The EDS analysis showed that some ProRoot MTA particles, differently from Aureoseal, contain Ca, Si, Al and Fe. Oblong particles in ProRoot and Aureoseal are rich of bismuth. The strong interest in developing new Portland cement-based endodontic sealers will create materials with increased handling characteristics and physicochemical properties. A thorough investigation on two cement powders was carried out by using XRF, XRD, SEM and EDS analysis. To date there was a lack of studies on Aureoseal Plus. This cement is similar in composition to ProRoot MTA. Despite that it has distinctive elements that could improve its characteristics, resulting in a good alternative to MTA.
Using X-Ray Fluorescence Technique to Quantify Metal Concentration in Coral Cores from Belize
NASA Astrophysics Data System (ADS)
Kingsley, C.; Bhattacharya, A.; Hangsterfer, A.; Carilli, J.; Field, D. B.
2016-12-01
Caribbean coral reefs are some of the most threatened marine ecosystems in the world. Research appears to suggest that environmental stressors of local origin, such as sediment run off, can reduce the resilience of these reefs to global threats such as ocean warming. Sedimentation can stunt coral growth, reduce its resilience, and it is possible that trapped material could render coral skeletons brittle (personal discussions). Material trapped in coral skeletons can provide information on the sources of particulate matter in the ocean ecosystem. Despite the importance of quantifying sources and types of materials trapped in corals, the research community is yet to fully develop techniques that allow accurate representation of trapped matter, which is potentially a major source of metal content in reef building coral skeletons. The dataset presented here explores the usefulness of X-Ray Fluorescence (XRF), a widely used tool in environmental studies (but generally not in corals), to estimate metal content in coral cores collected from four locations near Belize, with varying degrees of impact from coastal processes. The coral cores together cover a period of 1862-2006. Trace, major, and minor metal content from these cores have been well-studied using solution-based ICP-MS, providing us with the unique opportunity to test the efficacy of XRF technique in characterizing metal content in these coral cores. We have measured more than 50 metals using XRF every two millimeters along slabs removed from the middle of a coral core to characterize materials present in coral skeletons. We compared the results from XRF to solution-based ICP-MS - that involves dissolving subsamples of coral skeleton to measure metal content. Overall, it appears that the non-destructive XRF technique is a viable supplement in determining sediment and metal content in coral cores, and may be particularly helpful for assessing resistant phases such as grains of sediment that are not fully
NASA Astrophysics Data System (ADS)
Goldfarb, L. A.; Kingsley, C.; Urbalejo, A. A.; Hangsterfer, A.; Gee, J. S.; Carilli, J.; Feinberg, J. M.; Mitra, R.; Bhattacharya, A.; Field, D.
2017-12-01
Caribbean coral reefs are some of the most threatened marine ecosystems in the world. Research suggest that environmental stressors of local origin, such as sediment run off, can reduce the resilience of these reefs to global threats such as ocean warming. Material trapped in coral skeletons can provide information on the sources of particulate matter in the ocean ecosystem. Despite the importance of quantifying sources and types of materials trapped in corals, the research community is yet to fully develop techniques that allow accurate representation of trapped matter, which is potentially a major source of metal content in reef building coral skeletons. The dataset presented here is a progress and combination of two works presented at American Geophysical Union 2016 Fall Meeting; In this research, we explore the efficacy of X-Ray Fluorescence (XRF), a widely used tool in environmental studies (but generally not in corals), to estimate detrital metal content in coral cores collected from four locations near Belize, with varying degrees of impact from coastal processes. Four coral cores together cover a period of 1862-2006. Trace, major and minor metal content from these cores have been well-studied using solution-based ICP-MS, providing us with the unique opportunity to test the efficacy of XRF technique in characterizing metal content in these coral cores. We have measured more than 50 metals using XRF every two millimeters along slabs removed from the middle of a coral core spanning to characterize materials present in coral skeletons. We compare the results from XRF to elemental concentrations reported from solution-based ICP-MS. Furthermore, we also compare our XRF data to magnetic measurements we have made in these same coral cores. Overall, it appears that the non-destructive XRF technique is a viable supplement to the ICP-MS in determining sediment and metal content in coral cores, and may be particularly helpful for assessing resistant phases such as
NASA Astrophysics Data System (ADS)
Flude, Stephanie; Haschke, Michael; Tagle, Roald; Storey, Michael
2013-04-01
X-Ray Fluorescence (XRF) has long been used to provide valuable geochemical analysis of bulk rock samples in geological studies. However, it is a destructive technique, requiring samples to be homogenised by grinding to a fine powder and formed into a compacted pellet, or fused glass disk and the resulting sample has to be completely flat for reliable analysis. Until recently, non-destructive, high spatial resolution µ- XRF analysis was possible only at specialised Synchrotron radiation facilities, where high excitation beam energies are possible and specialised X-ray focussing optical systems are available. Recently, a number of bench-top µ-XRF systems have become available, allowing easy, rapid and non-destructive geochemical analysis of various materials. We present a number of examples of how the new bench-top M4 Tornado µ-XRF system, developed by Bruker Nano, can be used to provide valuable geochemical information on geological samples. Both quantitative and qualitative (in the form of X-Ray area-maps) data can be quickly and easily acquired for a wide range of elements (as light as Na, using a vacuum), with minimal sample preparation, using an X-Ray spot size as low as 25 µm. Large specimens up to 30 cm and 5 kg in weight can be analysed due to the large sample chamber, allowing non-destructive characterisation of rare or valuable materials. This technique is particularly useful in characterising heterogeneous samples, such as drill cores, sedimentary and pyroclastic rocks containing a variety of clasts, lavas sourced from mixed and mingled magmas, mineralised samples and fossils. An obvious application is the ability to produce element maps or line-scans of minerals, allowing zoning of major and trace elements to be identified and thus informing on crystallisation histories. An application of particular interest to 40Ar/39Ar geochronologists is the ability to screen and assess the purity of mineral separates, or to characterise polished slabs for
City Core - detecting the anthropocene in urban lake cores
NASA Astrophysics Data System (ADS)
Kjaer, K. H.; Ilsøe, P.; Andresen, C. S.; Rasmussen, P.; Andersen, T. J.; Frei, R.; Schreiber, N.; Odgaard, B.; Funder, S.; Holm, J. M.; Andersen, K.
2011-12-01
Here, we presents the preliminary results from lake cores taken in ditches associated with the historical fortifications enclosing the oldest - central Copenhagen to achieve new knowledge from sediment deposits related to anthropogenic activities. We have examined sediment cores with X-ray fluorescence (XRF) analyzers to correlate element patterns from urban and industrial emissions. Thus, we aim to track these patterns back in time - long before regular routines of recording of atmospheric environment began around 1978. Furthermore, we compare our data to alternative sources of information in order to constrain and expand the temporal dating limits (approximately 1890) achieved from 210Pb activity. From custom reports and statistic sources, information on imported volumes from coal, metal and oil was obtained and related contaminants from these substances to the sediment archives. Intriguingly, we find a steep increase in import of coal and metals matching the exponential increase of lead and zinc counts from XRF-recordings of the sediment cores. In this finding, we claim to have constrain the initiation of urban industrialization. In order to confirm the age resolution of the lake cores, DNA was extracted from sediments, sedaDNA. Thus we attempt to trace plantation of well documented exotic plants to, for instance, the Botanical Garden. Through extraction and sampling of sedaDNA from these floral and arboreal specimens we intend to locate their strataigraphic horizons in the sediment core. These findings may correlate data back to 1872, when the garden was established on the area of the former fortification. In this line of research, we hope to achieve important supplementary knowledge of sedaDNA-leaching frequencies within freshwater sediments.
Simultaneous fast scanning XRF, dark field, phase-, and absorption contrast tomography
NASA Astrophysics Data System (ADS)
Medjoubi, Kadda; Bonissent, Alain; Leclercq, Nicolas; Langlois, Florent; Mercère, Pascal; Somogyi, Andrea
2013-09-01
Scanning hard X-ray nanoprobe imaging provides a unique tool for probing specimens with high sensitivity and large penetration depth. Moreover, the combination of complementary techniques such as X-ray fluorescence, absorption, phase contrast and dark field imaging gives complete quantitative information on the sample structure, composition and chemistry. The multi-technique "FLYSCAN" data acquisition scheme developed at Synchrotron SOLEIL permits to perform fast continuous scanning imaging and as such makes scanning tomography techniques feasible in a time-frame well-adapted to typical user experiments. Here we present the recent results of simultaneous fast scanning multi-technique tomography performed at Soleil. This fast scanning scheme will be implemented at the Nanoscopium beamline for large field of view 2D and 3D multimodal imaging.
PyXRF: Python-based X-ray fluorescence analysis package
NASA Astrophysics Data System (ADS)
Li, Li; Yan, Hanfei; Xu, Wei; Yu, Dantong; Heroux, Annie; Lee, Wah-Keat; Campbell, Stuart I.; Chu, Yong S.
2017-09-01
We developed a python-based fluorescence analysis package (PyXRF) at the National Synchrotron Light Source II (NSLS-II) for the X-ray fluorescence-microscopy beamlines, including Hard X-ray Nanoprobe (HXN), and Submicron Resolution X-ray Spectroscopy (SRX). This package contains a high-level fitting engine, a comprehensive commandline/ GUI design, rigorous physics calculations, and a visualization interface. PyXRF offers a method of automatically finding elements, so that users do not need to spend extra time selecting elements manually. Moreover, PyXRF provides a convenient and interactive way of adjusting fitting parameters with physical constraints. This will help us perform quantitative analysis, and find an appropriate initial guess for fitting. Furthermore, we also create an advanced mode for expert users to construct their own fitting strategies with a full control of each fitting parameter. PyXRF runs single-pixel fitting at a fast speed, which opens up the possibilities of viewing the results of fitting in real time during experiments. A convenient I/O interface was designed to obtain data directly from NSLS-II's experimental database. PyXRF is under open-source development and designed to be an integral part of NSLS-II's scientific computation library.
NASA Astrophysics Data System (ADS)
Stockhecke, M.; Beck, C. C.; Brown, E. T.; Cohen, A.; Deino, A. L.; Feibel, C. S.; Sier, M.
2015-12-01
Outcrops in the Kenyan and Ethiopian rift valleys document repeated occurrences of freshwater lakes and wooded landscapes over the past 4 million years at locations that are currently seasonally-dry savanna. Studies of the rich fossil records, in combination with outcropping lacustrine sequences, led to major breakthroughs in our knowledge of driving factors in human evolution. However, study of continuous drill core from ancient lake basins provides a basis for to unravel East African climate dynamics in an unseen fashion. The Hominin Sites and Paleolakes Drilling Project (HSPDP), and the related Olorgesailie Drilling Project, recovered ~2 km of drill core since 2012. A major project goal is characterization of East African paleoclimate in order to evaluate its impact on hominin evolution. XRF core scanning data provide a means of evaluating records of past environmental conditions continuously and at high resolution. However, the HSPDP records contain complex lithologies reflecting repeated episodes of inundation and desiccation of the lake basins. Nevertheless, careful data evaluation based on detailed lithostratigraphy, which includes smear-slide microscopic analyses and X-radiographic images, allows disentanglement of complex signals and robust identification of continuous sequences for any cyclostratigraphic and statistical analysis. At the HSPDP Turkana Basin site a 175.6 m-long core the covers the Early Pleistocene time window during which hominids first expanded out of Africa and marine records document reorganization of tropical climate and the development of the strong Walker circulation. This drill site carries particular interest as it is located in only 2.5 km from the location of one of the most complete hominin skeletons ever recovered (Turkana Boy). Here we present a methodological approach to address the highly variable lithostratigraphy of the East African records to establish comprehensive and environmentally meaningful paleoclimate timeseries
NASA Astrophysics Data System (ADS)
Haflidason, H.; Thorsen, L.; Soldal, O. L.
2016-12-01
Following the initiation of the industrial revolution in Norway at the early 1900´s many of the heavy industrial factories established at that time were located in inner fjord systems of western Norway. The advantage was an easy access to cheap electricity, but the main disadvantage has been that the pollution from this industrial activity has been transported into fjord systems where the circulation of the water masses has been fairly limited leading to a high concentration of heavy metals in the fjord basin sediments. The recently developed non-destructive X-ray Fluorescence (XRF) core scanning technique offers new possibilities to obtain near-continuous records of bulk element composition in marine records. This new analytical geochemical method can measure the bulk element content directly from the surface sediment archives within a period of seconds and with a resolution up to 200 microns. By applying this method on rapidly deposited sediments one can reconstruct a continuous record of carbonate content on a sub-decadal to annual scale. This kind of high-resolution records can also be compared directly with historical and instrumental records from the same area. This offers new possibilities to identify in an effective way the geochemical anomalies in the sediment column and estimate the variability of the industrially produced elements as e.g. Cu, Zn and Pb and their distribution and thickness/quantity in fjord basin sediments. Examples will be presented demonstrating the close linkage between the industrial production history and the entrance of these elements in the fjord sediments. Identification of these elements offers an excellent opportunity to date the recent marine sediments using these elements as an event spike and also to reconstruct the history of pollution in these fjord basin sediments. As the precision of the XRF element detection is high the time of full recovery to natural conditions of the basin sediments, after close down of these
NASA Astrophysics Data System (ADS)
Alfeld, Matthias; Siddons, D. Peter; Janssens, Koen; Dik, Joris; Woll, Arthur; Kirkham, Robin; van de Wetering, Ernst
2013-04-01
In 17th century Old Master Paintings, the underpainting generally refers to the first sketch of a composition. The underpainting is applied to a prepared ground using a monochrome, brown oil paint to roughly indicate light, shade and contours. So far, methods to visualize the underpainting—other than in localized cross-sections—have been very limited. Neither infrared reflectography nor neutron induced autoradiography have proven to be practical, adequate visualization tools. Thus, although of fundamental interest in the understanding of a painting's genesis, the underpainting has virtually escaped all imaging efforts. In this contribution we will show that 17th century underpainting may consist of a highly heterogeneous mixture of pigments, including copper pigments. We suggest that this brown pigment mixture is actually the recycled left-over of a palette scraping. With copper as the heaviest exclusive elemental component, we will hence show in a case study on a Portrait of an Old Man attributed to Rembrandt van Rijn how scanning macro-XRF can be used to efficiently visualize the underpainting below the surface painting and how this information can contribute to the discussion of the painting's authenticity.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Greenberg, M.; Ebel, D.S.
2009-03-19
We present a nondestructive 3D system for analysis of whole Stardust tracks, using a combination of Laser Confocal Scanning Microscopy and synchrotron XRF. 3D deconvolution is used for optical corrections, and results of quantitative analyses of several tracks are presented. The Stardust mission to comet Wild 2 trapped many cometary and ISM particles in aerogel, leaving behind 'tracks' of melted silica aerogel on both sides of the collector. Collected particles and their tracks range in size from submicron to millimeter scale. Interstellar dust collected on the obverse of the aerogel collector is thought to have an average track length ofmore » {approx}15 {micro}m. It has been our goal to perform a total non-destructive 3D textural and XRF chemical analysis on both types of tracks. To that end, we use a combination of Laser Confocal Scanning Microscopy (LCSM) and X Ray Florescence (XRF) spectrometry. Utilized properly, the combination of 3D optical data and chemical data provides total nondestructive characterization of full tracks, prior to flattening or other destructive analysis methods. Our LCSM techniques allow imaging at 0.075 {micro}m/pixel, without the use of oil-based lenses. A full textural analysis on track No.82 is presented here as well as analysis of 6 additional tracks contained within 3 keystones (No.128, No.129 and No.140). We present a method of removing the axial distortion inherent in LCSM images, by means of a computational 3D Deconvolution algorithm, and present some preliminary experiments with computed point spread functions. The combination of 3D LCSM data and XRF data provides invaluable information, while preserving the integrity of the samples for further analysis. It is imperative that these samples, the first extraterrestrial solids returned since the Apollo era, be fully mapped nondestructively in 3D, to preserve the maximum amount of information prior to other, destructive analysis.« less
NASA Astrophysics Data System (ADS)
Abratis, Michael; Methe, Pascal; Aehnelt, Michaela; Kunkel, Cindy; Beyer, Daniel; Kukowski, Nina; Totsche, Kai Uwe
2014-05-01
cores were scanned for compositional variations using an XRF core scanner at the BGR lab and scan images of the slabbed surfaces were performed. The average core recovery rate was very high at nearly 100%. Altogether, we gained 533 m of excellent core material including sandstones, siltstones and claystones, carbonates, sulfates and chlorides. This provides valuable insight into the stratigraphic column of the Thuringian Syncline.
NASA Astrophysics Data System (ADS)
Reilly, B. T.; Stoner, J. S.; Wiest, J.; Abbott, M. B.; Francus, P.; Lapointe, F.
2015-12-01
Computed Tomography (CT) of sediment cores allow for high resolution images, three dimensional volumes, and down core profiles, generated through the attenuation of X-rays as a function of density and atomic number. When using a medical CT-Scanner, these quantitative data are stored in pixels using the Hounsfield scale, which are relative to the attenuation of X-rays in water and air at standard temperature and pressure. Here we present MATLAB based software specifically designed for sedimentary applications with a user friendly graphical interface to process DICOM files and stitch overlapping CT scans. For visualization, the software allows easy generation of core slice images with grayscale and false color relative to a user defined Hounsfield number range. For comparison to other high resolution non-destructive methods, down core Hounsfield number profiles are extracted using a method robust to coring imperfections, like deformation, bowing, gaps, and gas expansion. We demonstrate the usefulness of this technique with lacustrine sediment cores from the Western United States and Canadian High Arctic, including Fish Lake, Oregon, and Sawtooth Lake, Ellesmere Island. These sites represent two different depositional environments and provide examples for a variety of common coring defects and lithologies. The Hounsfield profiles and images can be used in combination with other high resolution data sets, including sediment magnetic parameters, XRF core scans and many other types of data, to provide unique insights into how lithology influences paleoenvironmental and paleomagnetic records and their interpretations.
NASA Astrophysics Data System (ADS)
Suzuki, Y.; Tada, R.; Nakagawa, T.; Gotanda, K.; Haraguchi, T.; Nagashima, K.; Irino, T.; Sugisaki, S.; Kojima, H.; Horiuchi, D.
2013-12-01
Lake Suigetsu in Central Japan is known for its annual lamination (varve) starting from 70kys ago. Extremely precise Age-depth model is established for SG06 core based on over 800 14C dates obtained on terrestrial leaf fossils and wiggle-matched to stalagmite 14C records constrained by varve counts (Staff et al., 2013). By projecting this age model to newly drilled core from the same site, we can obtain precisely age-controlled high resolution paleoenvironmental record around the Lake Suigetsu drainage. It is likely that detrital materials in Lake Suigetsu sediments have several different sources such as soil on the slopes around the lake itself, aeolian dust from inland Asia, and suspended particles supplied from Hasu river through lake Mikata, which is located immediately upstream of Lake Suigetsu and trapping most of coarse detrital grains. However, the relative contribution from each detrital source and its temporal changes are poorly known. The lack of knowledge on relative contribution of different detrital sources limits utility of detrital materials as proxies of paleo-environments. In this study, we are aiming to reconstruct the history of precipitation changes in the drainage area of Lake Suigetsu during the Holocene to explore the relationship between precipitation in the Japan Sea side of SW Japan, behavior of Asian monsoon system as an important component of the global climate system. It is well known that flux of suspended particles in rivers increases with precipitation. In order for us to be able to use the Hasu river's flux of suspended particles as the precipitation proxy, however, we first need to establish a simple and swift way to estimate the contribution of detrital materials from Hasu River flowing through Lake Mikata into Lake Suigetsu. We carried out color measurement with 5mm resolution on split half core surface of the sediment drilled in the summer of 2012(SG12), and compared these values to chemical composition data by XRF microscanner
NASA Astrophysics Data System (ADS)
Jian, Nan; Dowle, Miriam; Horniblow, Richard D.; Tselepis, Chris; Palmer, Richard E.
2016-11-01
As the major iron storage protein, ferritin stores and releases iron for maintaining the balance of iron in fauna, flora, and bacteria. We present an investigation of the morphology and iron loading of ferritin (from equine spleen) using aberration-corrected high angle annular dark field scanning transmission electron microscopy. Atom counting method, with size selected Au clusters as mass standards, was employed to determine the number of iron atoms in the nanoparticle core of each ferritin protein. Quantitative analysis shows that the nuclearity of iron atoms in the mineral core varies from a few hundred iron atoms to around 5000 atoms. Moreover, a relationship between the iron loading and iron core morphology is established, in which mineral core nucleates from a single nanoparticle, then grows along the protein shell before finally forming either a solid or hollow core structure.
A con-focal setup for micro-XRF experiments using diamond anvil cells
NASA Astrophysics Data System (ADS)
Wilke, Max; Rickers, Karen; Vincze, Laszlo; Schmidt, Christian; Borchert, Manuela; Pascarelli, Sakura
2010-05-01
In this contribution we introduce an experimental setup to perform con-focal micro X-ray fluorescence measurements in situ in samples at high temperatures and pressures in diamond anvil cells (DAC) (e.g. Schmidt et al. 2007). The con-focal arrangement is used to suppress the background in X-ray fluorescence (XRF) spectra that stems from elastic and inelastic scattering of the diamond anvils. The setup is based on a focusing optic in the incident beam that reaches a spot of 5-10 μm and a focusing poly-capillary in front of an energy-dispersive solid-state detector. The detector poly-capillary is designed to work at a very long working distance of 50 mm in order to collect the radiation from the center of the DAC at 90° to the incident beam. The probing volume is defined by the two foci and has a size of ca. 300 μm at 8 keV and 150 μm at 19 keV as measured by scans through thin metal foils. Comparison of XRF spectra acquired with a usual detector collimator and spectra recorded with the detector capillary shows a strong suppression of XRF signal generated outside the probed volume, i.e. XRF from the gasket material and signal from elastic and Compton scattering by the diamond anvils. The ratio of the Zr K-alpha fluorescence peak to the peak of the Compton scattering changes from 0.5 (collimator) to 1.26 (detector capillary) for a ca. 1000 ppm Zr standard solution and an incident beam energy of 20 keV. For a standard solution containing ca. 1000 ppm Hf, the ratio of the L-alpha to the Compton signal increases to 6 using the detector capillary and an incident beam energy of 9.7 keV. Thus, the con-focal setup substantially improves the fluorescence to background ratio. This will result in higher sensitivities for dilute elements in the sample chamber of the DAC. Furthermore, the possibilities of interference of the sample's signal with signal from the sample environment are greatly reduced. In a broader sense, the setup can also be applied to other confined samples
Proposal for a prototype of portable μXRF spectrometer
NASA Astrophysics Data System (ADS)
Polese, C.; Dabagov, S. B.; Esposito, A.; Liedl, A.; Hampai, D.; Bartùli, C.; Ferretti, M.
2015-07-01
μXRF is a powerful instrument for non-destructive characterization of materials of cultural interest. At the XLab Frascati Laboratory this technique is already well performed thanks to the polyCO set equipment allowing simultaneous μXRF 2D mapping. However, due to the strict demand for in situ analysis in this particular field, a new portable μXRF spectrometer equipped with a full polycapillary lens conjugated with a transmission anode X-ray tube is proposed. Many cultural objects are characterized by elements (Ag, Sn, etc.) with high energy fluorescence K-lines. Thus, the capability of a full lens to deliver a high energy fraction of X-ray spectrum, in order to excite the fluorescence K-lines of such elements, is tested.
NASA Astrophysics Data System (ADS)
de Winter, Niels; Goderis, Steven; van Malderen, Stijn; Vanhaecke, Frank; Claeys, Philippe
2016-04-01
A combination of laboratory micro-X-ray Fluorescence (μXRF) and stable carbon and oxygen isotope analysis shows that trace element profiles from modern horse molars reveal a seasonal pattern that co-varies with seasonality in the oxygen isotope records of enamel carbonate from the same teeth. A combination of six cheek teeth (premolars and molars) from the same individual yields a seasonal isotope and trace element record of approximately three years recorded during the growth of the molars. This record shows that reproducible measurements of various trace element ratios (e.g., Sr/Ca, Zn/Ca, Fe/Ca, K/Ca and S/Ca) lag the seasonal pattern in oxygen isotope records by 2-3 months. Laser Ablation-ICP-Mass Spectrometry (LA-ICP-MS) analysis on a cross-section of the first molar of the same individual is compared to the bench-top tube-excitation μXRF results to test the robustness of the measurements and to compare both methods. Furthermore, trace element (e.g. Sr, Zn, Mg & Ba) profiles perpendicular to the growth direction of the same tooth, as well as profiles parallel to the growth direction are measured with LA-ICP-MS and μXRF to study the internal distribution of trace element ratios in two dimensions. Results of this extensive complementary line-scanning procedure shows the robustness of state of the art laboratory micro-XRF scanning for the measurement of trace elements in bioapatite. The comparison highlights the advantages and disadvantages of both methods for trace element analysis and illustrates their complementarity. Results of internal variation within the teeth shed light on the origins of trace elements in mammal teeth and their potential use for paleo-environmental reconstruction.
EUTERPE, a small electron storage ring for XRF
NASA Astrophysics Data System (ADS)
Botman, J. I. M.; Mutsaers, P. H. A.; Hagedoorn, H. L.; De Voigt, M. J. A.
1990-04-01
A small-sized electron storage ring is under construction at the Eindhoven University of Technology which will cover the energy range of 15 to 400 MeV. At top energy the characteristic wavelength of the synchrotron radiation spectrum is 8.3 nm for the regular dipole magnets and 1.2 nm corresponding to 1.06 keV for a 10 T wiggler magnet. This will provide useful radiation for X-ray fluorescence (XRF) up to 3.2 keV. Alternatively, photon conversion with a high power CO 2 laser beam of 0.124 eV photons will generate X-rays for XRF with energies ranging from 0.5 to 300 keV, depending on the operating energy of the storage ring. This facility will provide an important extension to the activities of the Eindhoven group on PIXE, RBS and microbeam analysis. A short description of the macnine will be given together with applications and specific examples of the XRF method.
Prostate-cancer diagnosis by non-invasive prostatic Zinc mapping using X-Ray Fluorescence (XRF)
NASA Astrophysics Data System (ADS)
Cortesi, Marco
At present, the major screening tools (PSA, DRE, TRUS) for prostate cancer lack sensitivity and specificity, and none can distinguish between low-grade indolent cancer and high-grade lethal one. The situation calls for the promotion of alternative approaches, with better detection sensitivity and specificity, to provide more efficient selection of patients to biopsy and with possible guidance of the biopsy needles. The prime objective of the present work was the development of a novel non-invasive method and tool for promoting detection, localization, diagnosis and follow-up of PCa. The method is based on in-vivo imaging of Zn distribution in the peripheral zone of the prostate, by a trans-rectal X-ray fluorescence (XRF) probe. Local Zn levels, measured in 1--4 mm3 fresh tissue biopsy segments from an extensive clinical study involving several hundred patients, showed an unambiguous correlation with the histological classification of the tissue (Non-Cancer or PCa), and a systematic positive correlation of its depletion level with the cancer-aggressiveness grade (Gleason classification). A detailed analysis of computer-simulated Zn-concentration images (with input parameters from clinical data) disclosed the potential of the method to provide sensitive and specific detection and localization of the lesion, its grade and extension. Furthermore, it also yielded invaluable data on some requirements, such as the image resolution and counting-statistics, requested from a trans-rectal XRF probe for in-vivo recording of prostatic-Zn maps in patients. By means of systematic table-top experiments on prostate-phantoms comprising tumor-like inclusions, followed by dedicated Monte Carlo simulations, the XRF-probe and its components have been designed and optimized. Multi-parameter analysis of the experimental data confirmed the simulation estimations of the XRF detection system in terms of: delivered dose, counting statistics, scanning resolution, target-volume size and the
Xia, Jin-Lan; Liu, Hong-Chang; Nie, Zhen-Yuan; Peng, An-An; Zhen, Xiang-Jun; Yang, Yun; Zhang, Xiu-Li
2013-09-01
The differential expression of extracellular thiol groups by Acidithiobacillus ferrooxidans grown on substrates Fe(2+) and S(0) was investigated by using synchrotron radiation based scanning transmission X-ray microscopy (STXM) imaging and microbeam X-ray fluorescence (μ-XRF) mapping. The extracellular thiol groups (SH) were first alkylated by iodoacetic acid forming Protein-SCH2COOH and then the P-SCH2COOH was marked by calcium ions forming P-SCH2COOCa. The STXM imaging and μ-XRF mapping of SH were based on analysis of SCH2COO-bonded Ca(2+). The results indicated that the thiol group content of A. ferrooxidans grown on S(0) is 3.88 times to that on Fe(2+). Combined with selective labeling of SH by Ca(2+), the STXM imaging and μ-XRF mapping provided an in situ and rapid analysis of differential expression of extracellular thiol groups. © 2013.
Nondestructive Analysis of Astromaterials by Micro-CT and Micro-XRF Analysis for PET Examination
NASA Technical Reports Server (NTRS)
Zeigler, R. A.; Righter, K.; Allen, C. C.
2013-01-01
An integral part of any sample return mission is the initial description and classification of returned samples by the preliminary examination team (PET). The goal of the PET is to characterize and classify returned samples and make this information available to the larger research community who then conduct more in-depth studies on the samples. The PET tries to minimize the impact their work has on the sample suite, which has in the past limited the PET work to largely visual, nonquantitative measurements (e.g., optical microscopy). More modern techniques can also be utilized by a PET to nondestructively characterize astromaterials in much more rigorous way. Here we discuss our recent investigations into the applications of micro-CT and micro-XRF analyses with Apollo samples and ANSMET meteorites and assess the usefulness of these techniques in future PET. Results: The application of micro computerized tomography (micro-CT) to astromaterials is not a new concept. The technique involves scanning samples with high-energy x-rays and constructing 3-dimensional images of the density of materials within the sample. The technique can routinely measure large samples (up to approx. 2700 cu cm) with a small individual voxel size (approx. 30 cu m), and has the sensitivity to distinguish the major rock forming minerals and identify clast populations within brecciated samples. We have recently run a test sample of a terrestrial breccia with a carbonate matrix and multiple igneous clast lithologies. The test results are promising and we will soon analyze a approx. 600 g piece of Apollo sample 14321 to map out the clast population within the sample. Benchtop micro x-ray fluorescence (micro-XRF) instruments can rapidly scan large areas (approx. 100 sq cm) with a small pixel size (approx. 25 microns) and measure the (semi) quantitative composition of largely unprepared surfaces for all elements between Be and U, often with sensitivity on the order of a approx. 100 ppm. Our recent
Whole-rock analyses of core samples from the 1988 drilling of Kilauea Iki lava lake, Hawaii
Helz, Rosalind Tuthill; Taggart, Joseph E.
2010-01-01
This report presents and evaluates 64 major-element analyses of previously unanalyzed Kilauea Iki drill core, plus three samples from the 1959 and 1960 eruptions of Kilauea, obtained by X-ray fluorescence (XRF) analysis during the period 1992 to 1995. All earlier major-element analyses of Kilauea Iki core, obtained by classical (gravimetric) analysis, were reported and evaluated in Helz and others (1994). In order to assess how well the newer data compare with this earlier suite of analyses, a subset of 24 samples, which had been analyzed by classical analysis, was reanalyzed using the XRF technique; those results are presented and evaluated in this report also. The XRF analyses have not been published previously. This report also provides an overview of how the chemical variations observed in these new data fit in with the chemical zonation patterns and petrologic processes inferred in earlier studies of Kilauea Iki.
NHEXAS PHASE I ARIZONA STUDY--METALS-XRF IN DUST ANALYTICAL RESULTS
The Metals-XRF in Dust data set contains X-ray fluorescence (XRF) analytical results for measurements of up to 27 metals in 384 dust samples over 384 households. Samples were taken by collecting dust from the indoor floor areas in the main room and in the bedroom of the primary ...
NASA Astrophysics Data System (ADS)
Aida, S.; Matsuno, T.; Hasegawa, T.; Tsuji, K.
2017-07-01
Micro X-ray fluorescence (micro-XRF) analysis is repeated as a means of producing elemental maps. In some cases, however, the XRF images of trace elements that are obtained are not clear due to high background intensity. To solve this problem, we applied principal component analysis (PCA) to XRF spectra. We focused on improving the quality of XRF images by applying PCA. XRF images of the dried residue of standard solution on the glass substrate were taken. The XRF intensities for the dried residue were analyzed before and after PCA. Standard deviations of XRF intensities in the PCA-filtered images were improved, leading to clear contrast of the images. This improvement of the XRF images was effective in cases where the XRF intensity was weak.
NASA Astrophysics Data System (ADS)
Perneczky, L.; Rauwolf, M.; Ingerle, D.; Eichert, D.; Brigidi, F.; Jark, W.; Bjeoumikhova, S.; Pepponi, G.; Wobrauschek, P.; Streli, C.; Turyanskaya, A.
2018-07-01
The confocal μXRF spectrometer of Atominstitut (ATI) was transported and set up at the X-ray Fluorescence beamline at Elettra - Sincrotrone Trieste. It was successfully adjusted to the incoming beam (9.2 keV). Test measurements on a free-standing Cu wire were performed to determine the size of the focused micro-beam (non-confocal mode, 56 × 35 μm2) and the size of the confocal volume (confocal mode, 41 × 24 × 34 μm2) for the Cu-K α emission. In order to test the setup's capabilities, two areas on different human bone samples were measured in confocal scanning mode. For one of the samples the comparison with a previous μ XRF measurement, obtained with a low power X-ray tube in the lab, is presented.
NASA Astrophysics Data System (ADS)
O'Shea, Francis; Spencer, Kate; Brasington, James
2014-05-01
Historically, waste was deposited on low value, easily accessible coastal land (e.g. marsh land). Within England and Wales alone, there are over 5000 historical landfills situated within coastal areas at risk of flooding at a 1 in 100 year return period (Environment Agency, 2012). Historical sites were constructed prior to relevant legislation, and have no basal or side wall engineering, and the waste constituents are mostly unknown. In theory, contaminant concentrations should be reduced through natural attenuation as the leachate plume migrates through surrounding fine-grained inter-tidal sediments before reaching receptor waters. However, erosion resulting from rising sea level and increased storm intensity may re-distribute these sediments and release associated contaminants into the estuarine and coastal environment. The diffuse discharge from these sites has not been quantified and this presents a problem for those landfill managers who are required to complete EIAs. An earlier detailed field campaign at Newlands landfill site, on the Thames Estuary, UK identified a sub-surface (~2m depth) contaminant plume extending c. 20 m from the landfill boundary into surrounding fine-grained saltmarsh sediments. These saltmarsh sediments are risk of being eroded releasing their contaminant load to the Thames Estuary. The aims of this work were to; 1) assess whether this plume is representative of other historical landfills with similar characteristics and 2) to develop a rapid screening methodology using field portable XRF that could be used to identify potential risk of other coastal landfill sites. GIS was used to select landfill sites of similar age, hydrological regime and sedimentary setting in the UK, for comparison. Collection of sediment samples and analysis by ICP OES is expensive and time-consuming, therefore cores were extracted and analysed with a Niton Goldd XRF in-situ. Contaminant data were available immediately and the sampling strategy could be adapted
Identification of sandstone core damage using scanning electron microscopy
NASA Astrophysics Data System (ADS)
Ismail, Abdul Razak; Jaafar, Mohd Zaidi; Sulaiman, Wan Rosli Wan; Ismail, Issham; Shiunn, Ng Yinn
2017-12-01
Particles and fluids invasion into the pore spaces causes serious damage to the formation, resulting reduction in petroleum production. In order to prevent permeability damage for a well effectively, the damage mechanisms should be identified. In this study, water-based drilling fluid was compared to oil-based drilling fluids based on microscopic observation. The cores were damaged by several drilling fluid systems. Scanning electron microscope (SEM) was used to observe the damage mechanism caused by the drilling fluids. Results showed that the ester based drilling fluid system caused the most serious damage followed by synthetic oil based system and KCI-polymer system. Fine solids and filtrate migration and emulsion blockage are believed to be the major mechanisms controlling the changes in flow properties for the sandstone samples.
The Rontec PicoTAX x-ray fluorescence (XRF) analyzer was demonstrated under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program. The field portion of the demonstration was conducted in January 2005 at the Kennedy Athletic, Rec...
The Innov-X XT400 Series (XT400) x-ray fluorescence (XRF) analyzer was demonstrated under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program. The field portion of the demonstration was conducted in January 2005 at the Kenned...
Polycapillary based μXRF station for 3D colour tomography
NASA Astrophysics Data System (ADS)
Hampai, D.; Cherepennikov, Yu. M.; Liedl, A.; Cappuccio, G.; Capitolo, E.; Iannarelli, M.; Azzutti, C.; Gladkikh, Yu. P.; Marcelli, A.; Dabagov, S. B.
2018-04-01
The "Rainbow X-Ray" (RXR) experimental station at XLab Frascati of the Frascati's National Laboratories (LNF) INFN is a dedicated station for X-ray fluorescence studies based on the use of polycapillary lenses in a confocal geometry. The flexible RXR layout allows investigating specimens of the dimensions ranging from several millimeters up to half meter and weighting up to several tens of kilograms. Compared to similar existing XRF stations, apart of the possibility for investigating large samples, the main advantage of this equipment is the detection system with two spectrometers optimized to work separately at high and at low X-ray energies. The confocal geometry combined with a 3-axes fine motion system makes possible 3D μXRF elemental tomographic acquisitions (colour tomography). At present this station in operation at high XRF energies is used for cultural heritage and geological applications. We present and discuss here the analytical performances of this experimental station pointing out the advantages in different application areas.
In-Situ XRF Measurements in Lunar Surface Exploration Using Apollo Samples as a Standard
NASA Technical Reports Server (NTRS)
Young, Kelsey E.; Evans, C.; Allen, C.; Mosie, A.; Hodges, K. V.
2011-01-01
Samples collected during the Apollo lunar surface missions were sampled and returned to Earth by astronauts with varying degrees of geological experience. The technology used in these EVAs, or extravehicular activities, included nothing more advanced than traditional terrestrial field instruments: rock hammer, scoop, claw tool, and sample bags. 40 years after Apollo, technology is being developed that will allow for a high-resolution geochemical map to be created in the field real-time. Handheld x-ray fluorescence (XRF) technology is one such technology. We use handheld XRF to enable a broad in-situ characterization of a geologic site of interest based on fairly rapid techniques that can be implemented by either an astronaut or a robotic explorer. The handheld XRF instrument we used for this study was the Innov-X Systems Delta XRF spectrometer.
The Oxford ED2000 x-ray fluorescence (XRF) analyzer was demonstrated under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program. The field portion of the demonstration was conducted in January 2005 at the Kennedy Athletic, Recr...
Micro-XRF for In Situ Geological Exploration of Other Planets
NASA Technical Reports Server (NTRS)
Wade, Lawrence A.; Hodyss, Robert P.; Allwood, Abigail C.; Gao, Ning; Kozaczek, Kris
2013-01-01
In situ analysis of rock chemistry is a fundamental tool for exploration of planets. To meet this need, a high-spatial-resolution micro x-ray fluorescence (Micro-XRF) instrument was developed that is capable of determining the elemental composition of rocks (elements Na U) with 100 microns spatial resolution, thus providing insight to the composition of features as small as sand grains and individual laminae. The resulting excitation beam is of sufficient intensity that high signal-to-noise punctual spectra are acquired in seconds to a few minutes using an Amptek Silicon Drift Detector (SDD). The instrument features a tightly focused x-ray tube and HVPS developed by Moxtek that provides up to 200 micro-A at 10 to 50 keV, with a custom polycapillary optic developed by XOS Inc. and integrated into a breadboard Micro-XRF (see figure). The total mass of the complete breadboard instrument is 2.76 kg, including mounting hardware, mounting plate, camera, laser, etc. A flight version of this instrument would require less than 5W nominal power and 1.5 kg mass. The instrument includes an Amptek SDD that draws 2.5 W and has a resolution of 135 to 155 eV FWHM at 5.9 keV. It weighs 180 g, including the preamplifier, digital pulse processor, multichannel analyzer, detector and preamp power supplies, and packaging. Rock samples are positioned relative to the instrument by a three-axis arm whose position is controlled by closed-loop translators (mimicking the robotic arm of a rover). The distance from the source to the detector is calculated from the position of a focused laser beam on the sample as imaged by the camera. The instrument enables quick scans of major elements in only 1 second, and rapid acquisition (30 s) of data with excellent signal-to-noise and energy resolution for trace element analysis
NASA Astrophysics Data System (ADS)
Irmis, Randall; Olsen, Paul; Geissman, John; Gehrels, George; Kent, Dennis; Mundil, Roland; Rasmussen, Cornelia; Giesler, Dominique; Schaller, Morgan; Kürschner, Wolfram; Parker, William; Buhedma, Hesham
2017-04-01
The early Mesozoic is a critical time in earth history that saw the origin of modern ecosystems set against the back-drop of mass extinction and sudden climate events in a greenhouse world. Non-marine sedimentary strata in western North America preserve a rich archive of low latitude terrestrial ecosystem and environmental change during this time. Unfortunately, frequent lateral facies changes, discontinuous outcrops, and a lack of robust geochronologic constraints make lithostratigraphic and chronostratigraphic correlation difficult, and thus prevent full integration of these paleoenvironmental and paleontologic data into a regional and global context. The Colorado Plateau Coring Project (CPCP) seeks to remedy this situation by recovering a continuous cored record of early Mesozoic sedimentary rocks from the Colorado Plateau of the western United States. CPCP Phase 1 was initiated in 2013, with NSF- and ICDP-funded drilling of Triassic units in Petrified Forest National Park, northern Arizona, U.S.A. This phase recovered a 520 m core (1A) from the northern part of the park, and a 240 m core (2B) from the southern end of the park, comprising the entire Lower-Middle Triassic Moenkopi Formation, and most of the Upper Triassic Chinle Formation. Since the conclusion of drilling, the cores have been CT scanned at the University of Texas - Austin, and split, imaged, and scanned (e.g., XRF, gamma, and magnetic susceptibility) at the University of Minnesota LacCore facility. Subsequently, at the Rutgers University Core Repository, core 1A was comprehensively sampled for paleomagnetism, zircon geochronology, petrography, palynology, and soil carbonate stable isotopes. LA-ICPMS U-Pb zircon analyses are largely complete, and CA-TIMS U-Pb zircon, paleomagnetic, petrographic, and stable isotope analyses are on-going. Initial results reveal numerous horizons with a high proportion of Late Triassic-aged primary volcanic zircons, the age of which appears to be a close
Characterization of fossil remains using XRF, XPS and XAFS spectroscopies
NASA Astrophysics Data System (ADS)
Zougrou, I. M.; Katsikini, M.; Pinakidou, F.; Brzhezinskaya, M.; Papadopoulou, L.; Vlachos, E.; Tsoukala, E.; Paloura, E. C.
2016-05-01
Synchrotron radiation micro-X-Ray Fluorescence (μ-XRF), X-ray photoelectron (XPS) and X-ray Absorption Fine Structure (XAFS) spectroscopies are applied for the study of paleontological findings. More specifically the costal plate of a gigantic terrestrial turtle Titanochelon bacharidisi and a fossilized coprolite of the cave spotted hyena Crocuta crocuta spelaea are studied. Ca L 2,3-edge NEXAFS and Ca 2p XPS are applied for the identification and quantification of apatite and Ca containing minerals. XRF mapping and XAFS are employed for the study of the spatial distribution and speciation of the minerals related to the deposition environment.
U.S.-MEXICO BORDER PROGRAM ARIZONA BORDER STUDY--METALS/XRF IN DUST ANALYTICAL RESULTS
The Metals-XRF in Dust data set contains X-ray fluorescence (XRF) analytical results for measurements of up to 27 metals in 91 dust samples over 91 households. Samples were taken by collecting dust from the indoor floor areas in the main room and in the bedroom of the primary re...
Testing a laser-induced breakdown spectroscopy technique on the Arctic sediments
NASA Astrophysics Data System (ADS)
Han, D.; Nam, S. I.
2017-12-01
Physical and geochemical investigations coupled with the Laser-induced Breakdown Spectroscopy (LIBS) were performed on three surface sediment cores (ARA03B/24BOX, ARA02B/01(A)MUC, ARA02B/02MUC and ARA02B/03(A)MUC) recovered from the western Arctic Ocean (Chukchi Sea) during IBRV ARON expeditions in 2012. The LIBS technique was applied to carry out elemental chemical analysis of the Arctic sediments and compared with that measured by ITRAX X-ray fuorescence (XRF) core scanning. LIBS and XRF have shown similar elemental composition within each sediment core. In this study, mineral composition (XRD), grain size distribution and organic carbon content as well as elemental composition (LIBS) were all considered to understand paleoenvironmental changes (ocean circulation, sea-ice drift, iceberg discharge, and etc.) recorded in the Arctic Holocene sediment. Quantitative LIBS analysis shows a gradually varying distribution of the elements along the sampled core and clear separation between the cores. The cores are geochemically characterized by elevated Mn profile. The gradient of mineral composition and grain sizes among the cores shows regional distribution and variation in sedimentary condition due to geological distance between East Siberian and North America. The present study reveals that a LIBS technique can be employed for in-situ sediment analyses for the Arctic Ocean. Furthermore, LIBS does not require costly equipment, trained operators, and complicated sample pre-treatment processes compared to Atomic absorption spectroscopy (AAS) and inductively coupled plasma emission spectroscopy (ICP), and also known to show relatively high levels of sensitivity, precision, and distinction than XRF analysis, scanning electron microscopy-energy dispersive spectrometry (SEM-EDS), and electron probe X-ray microanalysis (EPMA).
Textural and Mineralogical Analysis of Volcanic Rocks by µ-XRF Mapping.
Germinario, Luigi; Cossio, Roberto; Maritan, Lara; Borghi, Alessandro; Mazzoli, Claudio
2016-06-01
In this study, µ-XRF was applied as a novel surface technique for quick acquisition of elemental X-ray maps of rocks, image analysis of which provides quantitative information on texture and rock-forming minerals. Bench-top µ-XRF is cost-effective, fast, and non-destructive, can be applied to both large (up to a few tens of cm) and fragile samples, and yields major and trace element analysis with good sensitivity. Here, X-ray mapping was performed with a resolution of 103.5 µm and spot size of 30 µm over sample areas of about 5×4 cm of Euganean trachyte, a volcanic porphyritic rock from the Euganean Hills (NE Italy) traditionally used in cultural heritage. The relative abundance of phenocrysts and groundmass, as well as the size and shape of the various mineral phases, were obtained from image analysis of the elemental maps. The quantified petrographic features allowed identification of various extraction sites, revealing an objective method for archaeometric provenance studies exploiting µ-XRF imaging.
NASA Astrophysics Data System (ADS)
Bowen, M. G.; Kulhanek, D. K.; Lyle, M. W.; Hahn, A.
2017-12-01
Variations in CaCO3 accumulation on the seafloor depend on a number of factors, including productivity of carbonate-producing organisms in the overlying water column, input of siliciclastic material from nearby continents, and changes in ocean chemistry. These factors are affected by variations in tectonics and climate. Here we use X-ray fluorescence (XRF) core scanning data to develop high-resolution chemical profiles calibrated with discrete samples to examine changes in carbonate production and burial in the eastern Arabian Sea. International Ocean Discovery Program (IODP) Expedition 355 cored two sites in the Indus Fan in Laxmi Basin. We scanned the Pleistocene composite sections from both sites at 2 cm resolution ( 150-300 year sampling resolution) using the Avaatech XRF core scanner at the IODP Gulf Coast Repository. In addition, we scanned a hemipelagic interval dated to the late Miocene ( 8 to 6 Ma) that spans the late Miocene climate transition to drier conditions globally, as documented by an expansion in C4 plants. The 2 cm scanning resolution represents 500 years between samples for the upper Miocene section. We used carbonate measurements on discrete samples to calibrate the XRF data, supplemented by analysis using a quantitative benchtop XRF at the University of Bremen. We find large variability in carbonate content in the Pleistocene and upper Miocene, varying from 15-80 wt%, with higher carbonate content correlating with lighter colored sediment. The aluminosilicate composition varies in part because of carbonate dilution but also because of changes in the source of clays and turbidites through the section. We also explore the use of chemical ratios to better understand the variations through the section. Changes in Ca/Fe (biogenic/terrestrial component) and Rb/Zr (fine/coarse grained) match well with visual observation of sediment composition in the cores. We can combine these with the oxygen isotope-derived age model for the Pleistocene section to
NASA Astrophysics Data System (ADS)
Jones, C.; Robinson, R. S.
2015-12-01
Coastal and equatorial upwelling in the Eastern Equatorial Pacific (EEP) are responsible for about 10% of the ocean's total production. The deep, cold, nutrient-rich waters supplied by upwelling originate in high latitudes, linking changes at high latitudes to the tropics. The Pliocene/Pleistocene transition which started around 2.7-3 million years ago (Ma) marked a period of higher variability in biological production and sea surface temperatures dominated by glacial/interglacial cycles. In addition, secular changes in the development of both Walker and Hadley cells appear to have impacted the strength of equatorial upwelling. However, the large positive production excursions, such as those found from 1.6 to 2.2 Ma, remain only moderately well characterized and both changes in high latitude nutrient supply and regional upwelling strength are implicated. ODP Site 846 is located in the heart of the EEP upwelling cold tongue and has ideal characteristics for examining these links and excursions. We present high-resolution (~0.5 ky) X-Ray Fluorescence (XRF) chemical profiles of Ca, Si, Ba, Mn, Fe, Al, and Ti, as well as a total nitrogen (TN%) record for the last 5 million years from ODP Site 846. We use these high resolution profiles in conjunction with other regional data to assess biogeochemical processes in the EEP over the last 5 million years. CaCO3 and SiO2 are the two dominant biogenic components and account for more than 95% of the sediment. BaSO4 and the discrete TN% measurements record total productivity. MnO and Fe2O3 are redox-sensitive species and are particularly suited to tracing dissolution related to excess bottom-water metabolic processes driven by high export production at the high-alkalinity Site 846. Al2O3 and TiO2 are tracers of terrigenous input. A transition between low amplitude and high amplitude carbonate cycles occurs at 2.8 Ma, coinciding with the Pliocene/Pleistocene transition to higher amplitude glacial cycles. Notable excursions from
Monitoring of WEEE plastics in regards to brominated flame retardants using handheld XRF
DOE Office of Scientific and Technical Information (OSTI.GOV)
Aldrian, Alexia, E-mail: alexia.aldrian@unileoben.ac.at; Ledersteger, Alfred, E-mail: a.ledersteger@saubermacher.at; Pomberger, Roland, E-mail: roland.pomberger@unileoben.ac.at
Highlights: • Specification of an empirical factor for conversion from bromine to PBB and PBDE. • The handheld XRF device was validated for this particular application. • A very large number of over 4600 pieces of monitor housings was analysed. • The recyclable fraction mounts up to 85% for TV but only 53% of PC waste plastics. • A high percentage of pieces with bromine contents of over 50,000 ppm was obtained. - Abstract: This contribution is focused on the on-site determination of the bromine content in waste electrical and electronic equipment (WEEE), in particular waste plastics from television setsmore » (TV) and personal computer monitors (PC) using a handheld X-ray fluorescence (XRF) device. The described approach allows the examination of samples in regards to the compliance with legal specifications for polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs) directly after disassembling and facilitates the sorting out of plastics with high contents of brominated flame retardants (BFRs). In all, over 3000 pieces of black (TV) and 1600 pieces of grey (PC) plastic waste were analysed with handheld XRF technique for this study. Especially noticeable was the high percentage of pieces with a bromine content of over 50,000 ppm for TV (7%) and PC (39%) waste plastics. The applied method was validated by comparing the data of handheld XRF with results obtained by GC–MS. The results showed the expected and sufficiently accurate correlation between these two methods. It is shown that handheld XRF technique is an effective tool for fast monitoring of large volumes of WEEE plastics in regards to BFRs for on-site measurements.« less
Monitoring of WEEE plastics in regards to brominated flame retardants using handheld XRF.
Aldrian, Alexia; Ledersteger, Alfred; Pomberger, Roland
2015-02-01
This contribution is focused on the on-site determination of the bromine content in waste electrical and electronic equipment (WEEE), in particular waste plastics from television sets (TV) and personal computer monitors (PC) using a handheld X-ray fluorescence (XRF) device. The described approach allows the examination of samples in regards to the compliance with legal specifications for polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs) directly after disassembling and facilitates the sorting out of plastics with high contents of brominated flame retardants (BFRs). In all, over 3000 pieces of black (TV) and 1600 pieces of grey (PC) plastic waste were analysed with handheld XRF technique for this study. Especially noticeable was the high percentage of pieces with a bromine content of over 50,000ppm for TV (7%) and PC (39%) waste plastics. The applied method was validated by comparing the data of handheld XRF with results obtained by GC-MS. The results showed the expected and sufficiently accurate correlation between these two methods. It is shown that handheld XRF technique is an effective tool for fast monitoring of large volumes of WEEE plastics in regards to BFRs for on-site measurements. Copyright © 2014 Elsevier Ltd. All rights reserved.
CT Scans of Cores Metadata, Barrow, Alaska 2015
Katie McKnight; Tim Kneafsey; Craig Ulrich
2015-03-11
Individual ice cores were collected from Barrow Environmental Observatory in Barrow, Alaska, throughout 2013 and 2014. Cores were drilled along different transects to sample polygonal features (i.e. the trough, center and rim of high, transitional and low center polygons). Most cores were drilled around 1 meter in depth and a few deep cores were drilled around 3 meters in depth. Three-dimensional images of the frozen cores were constructed using a medical X-ray computed tomography (CT) scanner. TIFF files can be uploaded to ImageJ (an open-source imaging software) to examine soil structure and densities within each core.
Remote In-Situ Quantitative Mineralogical Analysis Using XRD/XRF
NASA Technical Reports Server (NTRS)
Blake, D. F.; Bish, D.; Vaniman, D.; Chipera, S.; Sarrazin, P.; Collins, S. A.; Elliott, S. T.
2001-01-01
X-Ray Diffraction (XRD) is the most direct and accurate method for determining mineralogy. The CHEMIN XRD/XRF instrument has shown promising results on a variety of mineral and rock samples. Additional information is contained in the original extended abstract.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Wang, Lin, E-mail: lin.wang@insa-lyon.fr; Brémond, Georges; Sallet, Vincent
2016-08-29
ZnO/ZnO:Sb core-shell structured nanowires (NWs) were grown by the metal organic chemical vapor deposition method where the shell was doped with antimony (Sb) in an attempt to achieve ZnO p-type conduction. To directly investigate the Sb doping effect in ZnO, scanning capacitance microscopy (SCM) and scanning spreading resistance microscopy (SSRM) were performed on the NWs' cross-sections mapping their two dimensional (2D) local electrical properties. Although no direct p-type inversion in ZnO was revealed, a lower net electron concentration was pointed out for the Sb-doped ZnO shell layer with respect to the non-intentionally doped ZnO core, indicating an evident compensating effectmore » as a result of the Sb incorporation, which can be ascribed to the formation of Sb-related acceptors. The results demonstrate SCM/SSRM investigation being a direct and effective approach for characterizing radial semiconductor one-dimensional (1D) structures and, particularly, for the doping study on the ZnO nanomaterial towards its p-type realization.« less
NASA Astrophysics Data System (ADS)
Dietz, M.; Liu, K. B.; Bianchette, T. A.; Yao, Q.; McCloskey, T.
2016-12-01
Hurricanes Gustav and Ike consecutively impacted coastal Louisiana in 2008 and generated significant storm surges. Three sediment cores taken from Bay Champagne, a coastal backbarrier lake near Port Fourchon, Louisiana, clearly show a deposition layer of clastic sediment up to 17 cm thick attributable to these two storms. X-ray fluorescence (XRF) analysis indicates that the two storm events can be distinguished from one another based on contrasting geochemical profiles. The bottom layer, presumably deposited by Hurricane Gustav, has high concentrations of S, Cl, Ca, and Sr, suggesting a strong marine influence. The top layer, presumably attributed to Hurricane Ike, has high concentrations of Ti, Mn, Fe and Zn, indicative of material of terrestrial origin. The elemental concentration profiles suggest that the storm deposits in each core were deposited through two distinct hydrological processes: a storm surge -driven marine intrusion during Hurricane Gustav, followed by intensive freshwater flooding during Hurricane Ike. Using these deposits as modern analogs, this technique could be applied to characterize older storm layers in the sedimentary record and potentially provide information about their respective depositional mechanisms.
Barron, John A.; Bukry, David B.; Hendy, Ingrid L.
2015-01-01
Diatom and silicoflagellate assemblages documented in a high-resolution time series spanning 800 to 1600 AD in varved sediment recovered in Kasten core SPR0901-02KC (34°16.845’ N, 120°02.332’ W, water depth 588 m) from the Santa Barbara Basin (SBB) reveal that SBB surface water conditions during the Medieval Climate Anomaly (MCA) and the early part of the Little Ice Age (LIA) were not extreme by modern standards, mostly falling within one standard deviation of mean conditions during the pre anthropogenic interval of 1748 to 1900. No clear differences between the character of MCA and the early LIA conditions are apparent. During intervals of extreme droughts identified by terrigenous proxy scanning XRF analyses, diatom and silicoflagellate proxies for coastal upwelling typically exceed one standard deviation above mean values for 1748-1900, supporting the hypothesis that droughts in southern California are associated with cooler (or La Niña-like) sea surface temperatures (SSTs). Increased percentages of diatoms transported downslope generally coincide with intervals of increased siliciclastic flux to the SBB identified by scanning XRF analyses. Diatom assemblages suggest only two intervals of the MCA (at ~897 to 922 and ~1151 to 1167) when proxy SSTs exceeded one standard deviation above mean values for 1748 to 1900. Conversely, silicoflagellates imply extreme warm water events only at ~830 to 860 (early MCA) and ~1360 to 1370 (early LIA) that are not supported by the diatom data. Silicoflagellates appear to be more suitable for characterizing average climate during the 5 to 11 year-long sample intervals studied in the SPR0901-02KC core than diatoms, probably because diatom relative abundances may be dominated by seasonal blooms of a particular year.
Nie, LH; Sanchez, S; Newton, K; Grodzins, L; Cleveland, RO; Weisskopf, MG
2013-01-01
This study was conducted to investigate the methodology and feasibility of developing a portable XRF technology to quantify lead (Pb) in bone in vivo. A portable XRF device was set up and optimal setting of voltage, current, and filter combination for bone lead quantification were selected to achieve the lowest detection limit. The minimum radiation dose delivered to the subject was calculated by Monte Carlo simulations. An ultrasound device was used to measure soft tissue thickness to account for signal attenuation, and an alternative method to obtain soft tissue thickness from the XRF spectrum was developed and shown to be equivalent to the ultrasound measurements (Intraclass Correlation Coefficient, ICC=0.82). We tested the correlation of in vivo bone lead concentrations between the standard KXRF technology and the portable XRF technology. There was a significant correlation between the bone lead concentrations obtained from the standard KXRF technology and those obtained from the portable XRF technology (ICC=0.65). The detection limit for the portable XRF device was about 8.4 ppm with 2 mm soft tissue thickness. The entrance skin dose delivered to the human subject was about 13 mSv and the total body effective dose was about 1.5 μSv and should pose a minimal radiation risk. In conclusion, portable XRF technology can be used for in vivo bone lead measurement with sensitivity comparable to the KXRF technology and good correlation with KXRF measurements. PMID:21242629
MapX: 2D XRF for Planetary Exploration - Image Formation and Optic Characterization
Sarrazin, P.; Blake, D.; Gailhanou, M.; ...
2018-04-01
Map-X is a planetary instrument concept for 2D X-Ray Fluorescence (XRF) spectroscopy. The instrument is placed directly on the surface of an object and held in a fixed position during the measurement. The formation of XRF images on the CCD detector relies on a multichannel optic configured for 1:1 imaging and can be analyzed through the point spread function (PSF) of the optic. The PSF can be directly measured using a micron-sized monochromatic X-ray source in place of the sample. Such PSF measurements were carried out at the Stanford Synchrotron and are compared with ray tracing simulations. It is shownmore » that artifacts are introduced by the periodicity of the PSF at the channel scale and the proximity of the CCD pixel size and the optic channel size. A strategy of sub-channel random moves was used to cancel out these artifacts and provide a clean experimental PSF directly usable for XRF image deconvolution.« less
MapX: 2D XRF for Planetary Exploration - Image Formation and Optic Characterization
NASA Astrophysics Data System (ADS)
Sarrazin, P.; Blake, D.; Gailhanou, M.; Marchis, F.; Chalumeau, C.; Webb, S.; Walter, P.; Schyns, E.; Thompson, K.; Bristow, T.
2018-04-01
Map-X is a planetary instrument concept for 2D X-Ray Fluorescence (XRF) spectroscopy. The instrument is placed directly on the surface of an object and held in a fixed position during the measurement. The formation of XRF images on the CCD detector relies on a multichannel optic configured for 1:1 imaging and can be analyzed through the point spread function (PSF) of the optic. The PSF can be directly measured using a micron-sized monochromatic X-ray source in place of the sample. Such PSF measurements were carried out at the Stanford Synchrotron and are compared with ray tracing simulations. It is shown that artifacts are introduced by the periodicity of the PSF at the channel scale and the proximity of the CCD pixel size and the optic channel size. A strategy of sub-channel random moves was used to cancel out these artifacts and provide a clean experimental PSF directly usable for XRF image deconvolution.
MapX: 2D XRF for Planetary Exploration - Image Formation and Optic Characterization
DOE Office of Scientific and Technical Information (OSTI.GOV)
Sarrazin, P.; Blake, D.; Gailhanou, M.
Map-X is a planetary instrument concept for 2D X-Ray Fluorescence (XRF) spectroscopy. The instrument is placed directly on the surface of an object and held in a fixed position during the measurement. The formation of XRF images on the CCD detector relies on a multichannel optic configured for 1:1 imaging and can be analyzed through the point spread function (PSF) of the optic. The PSF can be directly measured using a micron-sized monochromatic X-ray source in place of the sample. Such PSF measurements were carried out at the Stanford Synchrotron and are compared with ray tracing simulations. It is shownmore » that artifacts are introduced by the periodicity of the PSF at the channel scale and the proximity of the CCD pixel size and the optic channel size. A strategy of sub-channel random moves was used to cancel out these artifacts and provide a clean experimental PSF directly usable for XRF image deconvolution.« less
Spatially resolved XRF, XAFS, XRD, STXM and IR investigation of a natural U-rich clay
NASA Astrophysics Data System (ADS)
Denecke, M. A.; Michel, P.; Schäfer, T.; Huber, F.; Rickers, K.; Rothe, J.; Dardenne, K.; Brendebach, B.; Vitova, T.; Elie, M.
2009-11-01
Combined spatially resolved hard X-ray μ-XRF and μ-XAFS studies using an X-ray beam with micrometer dimensions at the INE-Beamline for actinide research at ANKA and Beamline L at HASYLAB with those from scanning transmission soft X-ray microscopy (STXM) and synchrotron-based Fourier transform infrared microspectroscopy (μ-FTIR) recorded with beam spots in the nanometer range are used to study a U-rich clay originating from Autunian shales in the Permian Lodève Basin (France). This argillaceous formation is a natural U deposit associated with organic matter (bitumen). Results allow us to differentiate between possible mechanisms leading to U enrichment: likely U immobilization via reaction with organic material associated with clay mineral. Such investigations support development of reliable assessment of the long term radiological safety for proposed nuclear waste disposal sites.
NASA Astrophysics Data System (ADS)
Yanbe, Yutaka; Sato, Eiichi; Chiba, Hiraku; Maeda, Tomoko; Matsushita, Ryo; Oda, Yasuyuki; Hagiwara, Osahiko; Matsukiyo, Hiroshi; Osawa, Akihiro; Enomoto, Toshiyuki; Watanabe, Manabu; Kusachi, Shinya; Sato, Shigehiro; Ogawa, Akira
2013-09-01
X-ray fluorescence (XRF) analysis is useful for mapping various atoms in objects. Bremsstrahlung X-rays with energies beyond tantalum (Ta) K-edge energy 67.4 keV are absorbed effectively using a 100-µm-thick Ta filter, and the filtered X-rays including tungsten (W) Kα rays are absorbed by gadolinium (Gd) atoms in objects. The Gd XRF is then produced from Gd atoms in the objects and is counted by a cadmium telluride (CdTe) detector. Gd Kα photons with a maximum count rate of 1 kilo counts per second are dispersed using a multichannel analyzer, and the number of photons is counted by a counter card. The distance between the CdTe detector and the object is minimized to 40 mm to increase the count rate. The object is scanned using an x-y stage with a velocity of 5.0 mm/s, and Gd mapping are shown on a computer monitor. The scan steps of the x- and y-axes were both 2.5 mm, and the photon-counting time per mapping point was 0.5 s. We obtained Gd XRF images at high contrast, and Gd Kα photons were easily detected from cancerous regions in a nude mouse placed behind a 20-mm-thick poly(methyl methacrylate) plate.
NASA Astrophysics Data System (ADS)
Lin, Deng-Sung; Ku, Tsai-Shuan; Chen, Ru-Ping
2000-01-01
In this paper, we investigate the interaction of phosphine (PH3) on the Si(100)-2×1 surface at temperatures between 635 and 900 K. The hydrogen desorption, growth mode, surface morphology, and chemical composition and ordering of the surface layer are examined by synchrotron radiation core-level photoemission and real-time high-temperature scanning tunneling microscopy. The P 2p core-level spectra indicate that decomposition of PHn is complete above ~550 K and the maximum P coverage is strongly influenced by the growth temperature, which governs the coverage of H-terminated sites. The scanning tunneling microscopy (STM) images taken at real time during PH3 exposure indicate that a surface phosphorus atom readily and randomly displaces one Si atom from the substrate. The ejected Si diffuses, nucleates, and incorporates itself into islands or step edges, leading to similar growth behavior as that found in Si chemical vapor deposition. Line defects both perpendicular and parallel to the dimer rows are observed on the nearly P-saturated surface. Perpendicular line defects act as a strain relief mechanism. Parallel line defects result from growth kinetics. STM images also indicate that incorporating a small amount of phosphorus eliminates the line defects in the Si(100)-2×n surface.
NASA Astrophysics Data System (ADS)
Grant, Katharine M.; Rohling, Eelco J.; Westerhold, Thomas; Zabel, Matthias; Heslop, David; Konijnendijk, Tiuri; Lourens, Lucas
2017-09-01
Mediterranean sediments are valuable archives of both African monsoon variability and higher-latitude climate processes, and can also be used to provide an environmental context for early human migrations and settlements. However, the long history of Mediterranean palaeoclimate studies largely pre-dates the advent of widespread x-ray fluorescence (XRF) core-scanning, so there are few continuous and high-resolution geochemical records from this key region that extend beyond the last glacial cycle. Here we present XRF core-scanning results for ODP Site 967 (Eastern Mediterranean) that have been fully-calibrated into element concentrations spanning the last 3 million years (My). Comparison with independent geochemical data from conventional XRF highlights disparities for certain element/element ratios, thus suggesting the need for caution when taking ratios of scanning XRF data. Principal component analysis of the calibrated XRF dataset reveals two dominant components: detrital inputs (PC1) and a 'sapropel' (≈monsoon run-off) signal (PC2), which we use to establish a new orbitally-tuned chronology. We observe inverse covariation between PC2 and a previously published aeolian dust record from ODP Site 967 (Larrasoaña et al., 2003), and combine these records to produce a composite index of humidity and aridity for the wider North African region over the past 3 My. We propose that by combining run-off and dust signals in a single metric, our index captures the effects of both strengthening/northward migration (increased run-off) and weakening/southward retreat (increased dust) of the North African monsoon. Comparison of the index with published records of Northwest and East African palaeohumidity suggests that it tracks the timing of ;Green Sahara Periods; throughout the Plio-Pleistocene, and that at least 30 of these intervals coincided with increased humidity across East Africa. We tentatively suggest that these specific episodes may be termed ;pan-African Humid
NASA Astrophysics Data System (ADS)
Chang, Queenie; Lee, Jian-Cheng; Hunag, Jyh-Jaan; Wei, Kuo-Yen; Chen, Yue-Gau; Byrne, Timothy B.
2018-05-01
The source of fluvial deposits in terraces provides important information about the catchment fluvial processes and landform evolution. In this study, we propose a novel approach that combines high-resolution Itrax-XRF scanning and Canonical Discriminant Analysis (CDA) to identify the source of fine-grained fluvial terrace deposits. We apply this approach to a group of terraces that are located on the hanging wall of the Chihshang Fault in eastern Taiwan with two possible sources, the Coastal Range on the east and the Central Range on the west. Our results of standard samples from the two potential sources show distinct ranges of canonical variables, which provided a better separation ability than individual chemical elements. We then tested the possibility of using this approach by applying it to several samples with known sediment sources and obtain positive results. Applying this same approach to the fine-grained sediments in Chihshang terraces indicates that they are mostly composed of Coastal Range material but also contain some inputs from the Central Range. In two lowest terraces T1 and T2, the fine-grained deposits show significant Central Range component. For terrace T4, the results show less Central Range input and a trend of decreasing Central Range influences up section. The Coastal Range material becomes dominant in the two highest terraces T7 and T10. Sediments in terrace T5 appear to have been potentially altered by post-deposition chemical alteration processes and are not included in the analysis. Our results show that the change in source material in the terraces deposits was relatively gradual rather than the sharp changes suggested by the composition of the gravels and conglomerates. We suggest that this change in sources is related to the change in dominant fluvial processes that controlled by the tectonic activity.
NASA Astrophysics Data System (ADS)
Reddy, A.; Attaelmanan, A. G.; Mouton, M.
2012-07-01
The identification of more than 25% of the pottery sherds from the late PIR.D period (ca. 2nd - mid. 3rd c. AD) assemblage from the recently excavated building H at Mleiha as Indian is based on form and fabric, but using only visual assessment. Petrographic analysis of the fabrics can provide more precise indicators of the geographical origin of the wares. In this study, a total of 21 sherds from various key sites in Western India were compared with 7 different 'Indian' coarse-ware vessels sampled at Mleiha using X-ray fluorescence (XRF) spectrometry. The analyses were conducted on powdered samples collected from the core of each sherd. Each sample was irradiated for 1000 seconds using a 1.2 mm diameter X-ray beam. The resulting spectra were used for quantification of the X-ray intensity and elemental concentration. Levels of correlation in the elemental ratios of the sherds were statistically tested using an F-test as well as a Chi-test. Initial review of the XRF results indicates that the Maharashtra and Gujarat regions of India are probable source areas for at least two of the types of wares. Collection of additional samples from these areas and other regions of India, and further statistical analysis through methods such as Principal Component Analysis will help to isolate groups of wares from India and correlate them with types of vessels imported into the Oman peninsula in antiquity.
An optical supernova associated with the X-ray flash XRF 060218.
Pian, E; Mazzali, P A; Masetti, N; Ferrero, P; Klose, S; Palazzi, E; Ramirez-Ruiz, E; Woosley, S E; Kouveliotou, C; Deng, J; Filippenko, A V; Foley, R J; Fynbo, J P U; Kann, D A; Li, W; Hjorth, J; Nomoto, K; Patat, F; Sauer, D N; Sollerman, J; Vreeswijk, P M; Guenther, E W; Levan, A; O'Brien, P; Tanvir, N R; Wijers, R A M J; Dumas, C; Hainaut, O; Wong, D S; Baade, D; Wang, L; Amati, L; Cappellaro, E; Castro-Tirado, A J; Ellison, S; Frontera, F; Fruchter, A S; Greiner, J; Kawabata, K; Ledoux, C; Maeda, K; Møller, P; Nicastro, L; Rol, E; Starling, R
2006-08-31
Long-duration gamma-ray bursts (GRBs) are associated with type Ic supernovae that are more luminous than average and that eject material at very high velocities. Less-luminous supernovae were not hitherto known to be associated with GRBs, and therefore GRB-supernovae were thought to be rare events. Whether X-ray flashes--analogues of GRBs, but with lower luminosities and fewer gamma-rays--can also be associated with supernovae, and whether they are intrinsically 'weak' events or typical GRBs viewed off the axis of the burst, is unclear. Here we report the optical discovery and follow-up observations of the type Ic supernova SN 2006aj associated with X-ray flash XRF 060218. Supernova 2006aj is intrinsically less luminous than the GRB-supernovae, but more luminous than many supernovae not accompanied by a GRB. The ejecta velocities derived from our spectra are intermediate between these two groups, which is consistent with the weakness of both the GRB output and the supernova radio flux. Our data, combined with radio and X-ray observations, suggest that XRF 060218 is an intrinsically weak and soft event, rather than a classical GRB observed off-axis. This extends the GRB-supernova connection to X-ray flashes and fainter supernovae, implying a common origin. Events such as XRF 060218 are probably more numerous than GRB-supernovae.
NASA Astrophysics Data System (ADS)
Tuttle, L. F., II; Wernette, P. A.; Houser, C.
2016-12-01
Framework geology has been demonstrated to influence the geomorphology and affect the response of barrier islands to extreme storm events. Therefore, it is vital that we understand the framework geology before we can accurately assess the vulnerability and resiliency of the coast. Geophysical surveys consisting of ground-penetrating radar (GPR) and electromagnetic inductance (EMI) were collected along the length of Padre Island National Seashore (PAIS) to map subsurface infilled paleochannels identified in previous research. The most extensive published survey of PAIS framework geology was conducted in the 1950s as part of dredging the Intracoastal Waterway through Laguna Madre. Using cores and seismic surveys the previous study identified a series of relict infilled paleochannels in dissecting PAIS. The sediment cores presented in our poster were collected in Fall 2016 with a Geoprobe 6712DT. Cores were stored and processed using an X-ray fluorescence (XRF) scanner at the International Ocean Discovery Program repository in College Station, Texas. The XRF data was used to examine mineralogical differences that provide valuable insight into the evolutionary history of the island. This poster presents results from sediment cores collected to validate the geophysical survey data. The broader purpose of this research is to validate the subsurface framework geology features (i.e. infilled paleochannels) in order to more accurately predict future changes to the environmental and economic longevity of PAIS.
Application of Compton-suppressed self-induced XRF to spent nuclear fuel measurement
NASA Astrophysics Data System (ADS)
Park, Se-Hwan; Jo, Kwang Ho; Lee, Seung Kyu; Seo, Hee; Lee, Chaehun; Won, Byung-Hee; Ahn, Seong-Kyu; Ku, Jeong-Hoe
2017-11-01
Self-induced X-ray fluorescence (XRF) is a technique by which plutonium (Pu) content in spent nuclear fuel can be directly quantified. In the present work, this method successfully measured the plutonium/uranium (Pu/U) peak ratio of a pressurized water reactor (PWR)'s spent nuclear fuel at the Korea atomic energy research institute (KAERI)'s post irradiation examination facility (PIEF). In order to reduce the Compton background in the low-energy X-ray region, the Compton suppression system additionally was implemented. By use of this system, the spectrum's background level was reduced by a factor of approximately 2. This work shows that Compton-suppressed selfinduced XRF can be effectively applied to Pu accounting in spent nuclear fuel.
Online X-ray Fluorescence (XRF) Analysis of Heavy Metals in Pulverized Coal on a Conveyor Belt.
Yan, Zhang; XinLei, Zhang; WenBao, Jia; Qing, Shan; YongSheng, Ling; DaQian, Hei; Da, Chen
2016-02-01
Heavy metals in haze episode will continue to threaten the quality of public health around the world. In order to decrease the emission of heavy metals produced from coal burning, an online X-ray fluorescence (XRF) analyzer system, consisting of an XRF analyzer with data acquisition software and a laser rangefinder, was developed to carry out the measurement of heavy metals in pulverized coal. The XRF analyzer was mounted on a sled, which can effectively smooth the surface of pulverized coal and reduce the impact of surface roughness during online measurement. The laser rangefinder was mounted over the sled for measuring the distance between a pulverized coal sample and the analyzer. Several heavy metals and other elements in pulverized coal were online measured by the XRF analyzer directly above a conveyor belt. The limits of detection for Hg, Pb, Cr, Ti, Fe, and Ca by the analyzer were 44 ± 2, 34 ± 2, 17 ± 3, 41 ± 4, 19 ± 3, and 65 ± 2 mg·kg(-1), respectively. The relative standard deviation (%RSD) for the elements mentioned was less than 7.74%. By comparison with the results by inductively-coupled plasma mass spectrometry (ICP-MS), relative deviation (%D) of the online XRF analyzer was less than 10% for Cr, Ti, and Ca, in the range of 0.8-24.26% for Fe, and greater than 20% for Hg and Pb. © The Author(s) 2016.
Field dependence of the vortex core size probed by scanning tunneling microscopy
DOE Office of Scientific and Technical Information (OSTI.GOV)
Fente, A.; Herrera, E.; Guillamón, I.
We study the spatial distribution of the density of states (DOS) at zero bias N(r) in the mixed state of single and multigap superconductors. We provide an analytic expression for N(r) based on deGennes' relationship between DOS and the order parameter that reproduces well scanning tunneling microscopy (STM) data in several superconducting materials. In the single gap superconductor β-Bi 2 Pd, we find that N(r) is governed by a length scale ξ H =more » $$\\sqrt{Φ0/2πH}$$ which decreases in rising fields. The vortex core size $C$ ∝ (d Δ/dr| r→0) ₋1 differs from ξ H by a material dependent numerical factor. The new data on the tunneling conductance and vortex lattice of the 2H-NbSe 1.8S 0.2 show the in-plane isotropic vortices, suggesting that substitutional scattering removes the in-plane anisotropy found in the two-gap superconductor 2H-NbSe 2. We fit the tunneling conductance of 2H-NbSe 1.8S 0.2 to a two gap model and calculate the vortex core size $C$ for each band. We find that $C$ is field independent and has the same value for both bands. We also analyze the two-band superconductor 2H-NbSe 2 and find the same result. Lastly, we conclude that, independently of the magnetic field induced variation of the order parameter values in both bands, the spatial variation of the order parameter close to the vortex core is the same for all bands.« less
Field dependence of the vortex core size probed by scanning tunneling microscopy
Fente, A.; Herrera, E.; Guillamón, I.; ...
2016-07-29
We study the spatial distribution of the density of states (DOS) at zero bias N(r) in the mixed state of single and multigap superconductors. We provide an analytic expression for N(r) based on deGennes' relationship between DOS and the order parameter that reproduces well scanning tunneling microscopy (STM) data in several superconducting materials. In the single gap superconductor β-Bi 2 Pd, we find that N(r) is governed by a length scale ξ H =more » $$\\sqrt{Φ0/2πH}$$ which decreases in rising fields. The vortex core size $C$ ∝ (d Δ/dr| r→0) ₋1 differs from ξ H by a material dependent numerical factor. The new data on the tunneling conductance and vortex lattice of the 2H-NbSe 1.8S 0.2 show the in-plane isotropic vortices, suggesting that substitutional scattering removes the in-plane anisotropy found in the two-gap superconductor 2H-NbSe 2. We fit the tunneling conductance of 2H-NbSe 1.8S 0.2 to a two gap model and calculate the vortex core size $C$ for each band. We find that $C$ is field independent and has the same value for both bands. We also analyze the two-band superconductor 2H-NbSe 2 and find the same result. Lastly, we conclude that, independently of the magnetic field induced variation of the order parameter values in both bands, the spatial variation of the order parameter close to the vortex core is the same for all bands.« less
PXRF, μ-XRF, vacuum μ-XRF, and EPMA analysis of Email Champlevé objects present in Belgian museums.
Van der Linden, Veerle; Meesdom, Eva; Devos, Annemie; Van Dooren, Rita; Nieuwdorp, Hans; Janssen, Elsje; Balace, Sophie; Vekemans, Bart; Vincze, Laszlo; Janssens, Koen
2011-10-01
The enamel of 20 Email Champlevé objects dating between the 12th and 19th centuries was investigated by means of microscopic and portable X-ray fluorescence analysis (μ-XRF and PXRF). Seven of these objects were microsampled and the fragments were analyzed with electron probe microanalysis (EPMA) and vacuum μ-XRF to obtain quantitative data about the composition of the glass used to produce these enameled objects. As a result of the evolution of the raw materials employed to produce the base glass, three different compositional groups could be discriminated. The first group consisted of soda-lime-silica glass with a sodium source of mineral origin (with low K content) that was opacified by addition of calcium antimonate crystals. This type of glass was only used in objects made in the 12th century. Email Champlevé objects from the beginning of the 13th century onward were enameled with soda-lime-silica glass with a sodium source of vegetal origin. This type of glass, which has a higher potassium content, was opacified with SnO2 crystals. The glass used for 19th century Email Champlevé artifacts was produced with synthetic and purified components resulting in a different chemical composition compared to the other groups. Although the four analytical techniques employed in this study have their own specific characteristics, they were all found to be suitable for classifying the objects into the different chronological categories.
Elemental analysis using ED-XRF and 14C dating of Cuman wall paintings samples
NASA Astrophysics Data System (ADS)
Brocchieri, J.; Sabbarese, C.; Marzaioli, F.; Passariello, I.; Terrasi, F.; De Maio, C.; Ferrara, L.
2018-04-01
The aim of the present research was to analyse pigments and mortars of fresco fragments located at Cuma (Naples, Italy). The ED-XRF technique and 14C dating were used to establish the nature of the pigments and the age of mortars, respectively. ED-XRF results allowed to determine the elemental composition of the pigments that identified the colours and, hence, the historical period of completion. The 14C dating, applied to mortars using a particular preparation, provided results that are in accordance with the archaeological information within the 2σ interval range.
Submarine landslide identified in DLW3102 core of the northern continental slope, South China Sea
NASA Astrophysics Data System (ADS)
Xu, Yuanqin; Liu, Lejun; Zhou, Hang; Huang, Baoqi; Li, Ping; Ma, Xiudong; Dong, Feiyin
2018-02-01
In this paper, we take DLW3101 core obtained at the top of the canyon (no landslide area) and DLW3102 core obtained at the bottom of the canyon (landslide area) on the northern continental slope of the South China Sea as research objects. The chronostratigraphic framework of the DLW3101 core and elemental strata of the DLW3101 core and the DLW3102 core since MIS5 are established by analyzing oxygen isotope, calcium carbonate content, and X-Ray Fluorescence (XRF) scanning elements. On the basis of the information obtained by analyzing the sedimentary structure and chemical elements in the landslide deposition, we found that the DLW3102 core shows four layers of submarine landslides, and each landslide layer is characterized by high Si, K, Ti, and Fe contents, thereby indicating terrigenous clastic sources. L1 (2.15-2.44 m) occurred in MIS2, which is a slump sedimentary layer with a small sliding distance and scale. L2 (15.48-16.00 m) occurred in MIS5 and is a debris flow-deposited layer with a scale and sliding distance that are greater than those of L1. L3 (19.00-20.90 m) occurred in MIS5; its upper part (19.00-20.00 m) is a debris flow-deposited layer, and its lower part (20.00-20.90 m) is a sliding deposition layer. The landslide scale of L3 is large. L4 (22.93-24.27 m) occurred in MIS5; its upper part (22.93-23.50 m) is a turbid sedimentary layer, and its lower part (23.50-24.27 m) is a slump sedimentary layer. The landslide scale of L4 is large.
Sackett, Penelope C.; McConnell, Vicki S.; Roach, Angela L.; Priest, Susan S.; Sass, John H.
1999-01-01
Phase III of the Long Valley Exploratory Well, the Long Valley Coring Project, obtained continuous core between the depths of 7,180 and 9,831 ft (2,188 to 2,996 meters) during the summer of 1998. This report contains a compendium of information designed to facilitate post-drilling research focussed on the study of the core. Included are a preliminary stratigraphic column compiled primarily from field observations and a general description of well lithology for the Phase III drilling interval. Also included are high-resolution digital photographs of every core box (10 feet per box) as well as scanned images of pieces of recovered core. The user can easily move from the stratigraphic column to corresponding core box photographs for any depth. From there, compressed, "unrolled" images of the individual core pieces (core scans) can be accessed. Those interested in higher-resolution core scans can go to archive CD-ROMs stored at a number of locations specified herein. All core is stored at the USGS Core Research Center in Denver, Colorado where it is available to researchers following the protocol described in this report. Preliminary examination of core provided by this report and the archive CD-ROMs should assist researchers in narrowing their choices when requesting core splits.
NASA Technical Reports Server (NTRS)
Young, K. E.; Hodges, K. V.; Evans, C. A.
2012-01-01
While large-footprint X-ray fluorescence (XRF) instruments are reliable providers of elemental information about geologic samples, handheld XRF instruments are currently being developed that enable the collection of geochemical data in the field in short time periods (approx.60 seconds) [1]. These detectors are lightweight (1.3kg) and can provide elemental abundances of major rock forming elements heavier than Na. While handheld XRF detectors were originally developed for use in mining, we are working with commercially available instruments as prototypes to explore how portable XRF technology may enable planetary field science [2,3,4]. If an astronaut or robotic explorer visited another planetary surface, the ability to obtain and evaluate geochemical data in real-time would be invaluable, especially in the high-grading of samples to determine which should be returned to Earth. We present our results on the evaluation of handheld XRF technology as a geochemical tool in the context of planetary exploration.
Andrew Fowler
2015-04-01
Analytical results for X-ray fluorescence (XRF) and inductively coupled plasma mass spectrometry (ICP-MS) measurement of major, trace and rare earth elements in drill core from geothermal wells in Reykjanes, Iceland. Total Fe was analyzed as FeO, therefore is not included under the Fe2O3 column.
A Combined XRD/XRF Instrument for Lunar Resource Assessment
NASA Technical Reports Server (NTRS)
Vaniman, D. T.; Bish, D. L.; Chipera, S. J.; Blacic, J. D.
1992-01-01
Robotic surface missions to the Moon should be capable of measuring mineral as well as chemical abundances in regolith samples. Although much is already known about the lunar regolith, our data are far from comprehensive. Most of the regolith samples returned to Earth for analysis had lost the upper surface, or it was intermixed with deeper regolith. This upper surface is the part of the regolith most recently exposed to the solar wind; as such it will be important to resource assessment. In addition, it may be far easier to mine and process the uppermost few centimeters of regolith over a broad area than to engage in deep excavation of a smaller area. The most direct means of analyzing the regolith surface will be by studies in situ. In addition, the analysis of the impact-origin regolith surfaces, the Fe-rich glasses of mare pyroclastic deposits, are of resource interest, but are inadequately known; none of the extensive surface-exposed pyroclastic deposits of the Moon have been systematically sampled, although we know something about such deposits from the Apollo 17 site. Because of the potential importance of pyroclastic deposits, methods to quantify glass as well as mineral abundances will be important to resource evaluation. Combined x ray diffraction (XRD) and x ray fluorescence (XRF) analysis will address many resource characterization problems on the Moon. XRF methods are valuable for obtaining full major-element abundances with high precision. Such data, collected in parallel with quantitative mineralogy, permit unambiguous determination of both mineral and chemical abundances where concentrations are high enough to be of resource grade. Collection of both XRD and XRF data from a single sample provides simultaneous chemical and mineralogic information. These data can be used to correlate quantitative chemistry and mineralogy as a set of simultaneous linear equations, the solution of which can lead to full characterization of the sample. The use of
DELAMINATION AND XRF ANALYSIS OF NIST LEAD IN PAINT FILM STANDARDS
The objectives of this protocol were to remove the laminate coating from lead paint film standards acquired from NIST by means of surface heating. The average XRF value did not change after removal of the polymer coating suggesting that this protocol is satisfactory for renderin...
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kundu, Biswajit; Chakrabarti, Sudipto; Pal, Amlan J., E-mail: sspajp@iacs.res.in
2016-03-14
Core-shell nanocrystals having a type-I band-alignment confine charge carriers to the core. In this work, we choose CdSe/CdS core-shell nano-heterostructures that evidence confinement of holes only. Such a selective confinement occurs in the core-shell nanocrystals due to a low energy-offset of conduction band (CB) edges resulting in delocalization of electrons and thus a decrease in the conduction band-edge. Since the delocalization occurs through a thermal assistance, we study temperature dependence of selective delocalization process through scanning tunneling spectroscopy. From the density of states (DOS), we observe that the electrons are confined to the core at low temperatures. Above a certainmore » temperature, they become delocalized up to the shell leading to a decrease in the CB of the core-shell system due to widening of quantum confinement effect. With holes remaining confined to the core due to a large offset in the valence band (VB), we record the topography of the core-shell nanocrystals by probing their CB and VB edges separately. The topographies recorded at different temperatures representing wave-functions of electrons and holes corresponded to the results obtained from the DOS spectra. The results evidence temperature-dependent wave-function delocalization of one-type of carriers up to the shell layer in core-shell nano-heterostructures.« less
Comparison of soil pollution concentrations determined using AAS and portable XRF techniques.
Radu, Tanja; Diamond, Dermot
2009-11-15
Past mining activities in the area of Silvermines, Ireland, have resulted in heavily polluted soils. The possibility of spreading pollution to the surrounding areas through dust blow-offs poses a potential threat for the local communities. Conventional environmental soil and dust analysis techniques are very slow and laborious and consequently there is a need for fast and accurate analytical methods, which can provide real-time in situ pollution mapping. Laboratory-based aqua regia acid digestion of the soil samples collected in the area followed by the atomic absorption spectrophotometry (AAS) analysis confirmed very high pollution, especially by Pb, As, Cu, and Zn. In parallel, samples were analyzed using portable X-ray fluorescence radioisotope and miniature tube powered (XRF) NITON instruments and their performance was compared. Overall, the portable XRF instrument gave excellent correlation with the laboratory-based reference AAS method.
A novel XRF method to measure environmental release of copper and zinc from antifouling paints.
Ytreberg, Erik; Lagerström, Maria; Holmqvist, Albin; Eklund, Britta; Elwing, Hans; Dahlström, Magnus; Dahl, Peter; Dahlström, Mia
2017-06-01
The release of copper (Cu) and zinc (Zn) from vessels and leisure crafts coated with antifouling paints can pose a threat to water quality in semi-enclosed areas such as harbors and marinas as well as to coastal archipelagos. However, no reliable, practical and low-cost method exists to measure the direct release of metals from antifouling paints. Therefore, the paint industry and regulatory authorities are obliged to use release rate measurements derived from either mathematical models or from laboratory studies. To bridge this gap, we have developed a novel method using a handheld X-Ray Fluorescence spectrometer (XRF) to determine the cumulative release of Cu and Zn from antifouling paints. The results showed a strong linear relationship between XRF K α net intensities and metal concentrations, as determined by ICP-MS. The release of Cu and Zn were determined for coated panels exposed in harbors located in the Baltic Sea and in Kattegat. The field study showed salinity to have a strong impact on the release of Cu, i.e. the release increased with salinity. Contrary, the effect of salinity on Zn was not as evident. As exemplified in this work, the XRF method also makes it possible to identify the governing parameters to the release of Cu and Zn, e.g. salinity and type of paint formulation. Thus, the XRF method can be used to measure environmentally relevant releases of metallic compounds to design more efficient and optimized antifouling coatings. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.
Micro-XRF analysis of silver coins from medieval Poland
NASA Astrophysics Data System (ADS)
del Hoyo-Meléndez, Julio M.; Świt, Paweł; Matosz, Marta; Woźniak, Mateusz; Klisińska-Kopacz, Anna; Bratasz, Łukasz
2015-04-01
X-ray fluorescence (XRF) analysis has become a standard method in archaeological science due to its non-invasive and non-destructive nature. This technique has extensively been used for the study of numismatic collections since the data derived from it can be correlated with manufacturing processes, provenance of raw materials, and geographical distribution of ancient mints. A group of 71 silver coins of the first Piasts: Boleslaus the Brave (996-1025) and Mieszko II Lambert (1025-1034) belonging to the collections of the National Museum in Krakow have been characterized using micro-XRF spectrometry. This is the most numerous collection of their coins representing nearly 30% of all known coins from these rulers. The research has focused on evaluating the use of this technique as a screening tool for elemental surface characterization of the alloys. Surveyed coins are mainly constituted by Ag, Cu and Pb along with trace levels of Fe, Ni, Zn, Au, Hg, Bi, and Br. Quantitative analyses have revealed Ag contents in the 81.6-97.5% range for all the evaluated coins. This study had the goal of providing information about the elemental composition of these objects, which will serve to enhance the existing knowledge about geographical and chronological diversification of Polish numismatic collections.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Steeb, Jennifer L.; Mertz, Carol J.; Finck, Martha R.
X-ray fluorescence (XRF) is an attractive technique for nuclear forensics applications. We evaluated a handheld, portable XRF device by applying an external radiation field (10 mR/h to 17 R/h) using two types of radiography sources: a 60Co radiography camera to observe effects from high-energy gamma emissions and an 192Ir radiography camera to observe effects from several low-energy gamma (0.604, 0.468, and 0.317 MeV) and decay daughter x-ray emissions. External radiation tests proved that radiation, in general, has a significant effect on the dead time or background at dose rates over 1 R/hr for both the 192Ir and 60Co sources.
µ-XANES AND µ-XRF INVESTIGATIONS OF METAL BINDING MECHANISMS IN BIOSOLIDS
Micro-X-ray fluorescence (µ-XRF) microprobe analysis and micro-X-ray absorption near edge spectroscopy (µ-XANES) were employed to identify Fe and Mn phases and their association with selected toxic elements in two biosolids (limed composted and Nu-Earth) containing low ...
NASA Astrophysics Data System (ADS)
Dredge, Paula; Ives, Simon; Howard, Daryl L.; Spiers, Kathryn M.; Yip, Andrew; Kenderdine, Sarah
2015-11-01
A portrait of Henry VIII on oak panel c. 1535 has recently undergone technical examination to inform questions regarding authorship and the painting's relationship to a group of similar works in the collections of the National Portrait Gallery, London, and the Society of Antiquaries. Due to previous conservation treatments of the painting, the conventional transmission X-radiograph image was difficult to interpret. As a result, the painting underwent high-definition X-ray fluorescence (XRF) elemental mapping on the X-ray fluorescence microscopy beamline of the Australian Synchrotron. Scans were conducted at 12.6 and 18.5 keV, below and above the lead (Pb) L edges, respectively. Typical scan parameters were 120 μm pixel size at 7 ms dwell time, with the largest scan covering an area 545 × 287 mm2 collected in 23 h (10.8 MP). XRF mapping of the panel has guided the conservation treatment of the painting and the revelation of previously obscured features. It has also provided insight into the process of making of the painting. The informative and detailed elemental maps, alongside ultra-high-definition scans of the painting undertaken before and after varnish and over-paint removal, have assisted in comparison of the finely painted details with the London paintings. The resolution offered by the combination of imaging techniques identifies pigment distribution at an extremely fine scale, enabling a new understanding of the artist's paint application.
XRF and XANES Data for Kaplan U Paper
The dataset contains two XRF images of iron and uranium distribution on plant roots and a database of XANES data used to produce XANES spectra figure for Figure 7 in the published paper.This dataset is associated with the following publication:Kaplan, D., R. Kukkadapu, J. Seaman, B. Arey, A. Dohnalkova, S. Buettner, D. Li, T. Varga, K. Scheckel, and P. Jaffe. Iron Mineralogy and Uranium-Binding Environment in the Rhizosphere of a Wetland Soil. D. Barcelo SCIENCE OF THE TOTAL ENVIRONMENT. Elsevier BV, AMSTERDAM, NETHERLANDS, 569: 53-64, (2016).
NASA Astrophysics Data System (ADS)
Hsiung, K. H.; Kanamatsu, T.; Ikehara, K.; Usami, K.; Saito, S.; Murayama, M.
2017-12-01
The southwest Ryukyu Trench near Taiwan is an ideal place for source-to-sink studies based on the distinctive sediment transport route between the terrestrial sediment source in Taiwan and the marine sink in the Ryukyu Trench. Using the bathymetric and seismic reflection data, we develop a sediment transport routes for understanding the ultimate sink of the southwest Ryukyu Trench floor. The southwest Ryukyu Trench floor can be regarded as the most distal depositional basin and isolated from the Ryukyu forearc basins. In addition, part of sediment from the proximal sources of the Ryukyu Islands and Yaeyama accretionary prism could be transported to the trench floor. We collected the piston core, PC04, from the southwest Ryukyu Trench floor of 6,147 m water depth in 3.23 m core length from cruise KR15-18, 2015. The coring site locates behind the natural levee of an obvious channel in the Ryukyu trench floor. The PC04 is composed of gray silty clay interbedded with numerous silt layers. Most of the silt layers are less than 2 cm in thickness. Based upon the core observation, X-ray fluorescence core scanning analysis and 14C age determinations, thirty-seven individual and thin beds were determined as turbidites. The results of X-ray fluorescence core scanning analysis provide continuous and high-resolution (1.0 mm of each point) assessment of relative change in the elemental ratios. Ca/Fe is a proxy for the terrigenous component of the sediment, indicating the High Ca and low Fe of each turbidite layers. Zr/Rb ratios of the marine sediments commonly used in the reflection of the original grain size variation. A large part of deep-sea turbidite beds are characterized by high Ca/Fe and Zr/Rb ratio values. These turbidite beds can be linked spatially over a distance of ˜200 km via submarine canyons within the Taiwan orogen. However, it is difficult to be linked temporally to certain events.
NASA Astrophysics Data System (ADS)
Gasanova, Svetlana; Hermon, Sorin
2017-07-01
The present study describes a novel approach to the study of hidden by integrating the non-invasive micro-X-Ray Fluorescence spectroscopy, X-radiography and digital microscopy. The case study analysed is a portrait of a male figure discovered under the painting of Ecce Homo, attributed to Titian's studio with an estimated date in the 1550s. The X-radiography images exposed the details of the underpainting, which appeared to be a nearly finished portrait of a standing man, overpainted by the current composition of Ecce Homo at a 180° angle. The microscopy observations of the upper painting's cracks and flaked areas enabled the study of the exposed underlayers in terms of their colour appearance and pigment particles. The subsequent pigment analysis was performed by micro-XRF. Since the described XRF analysis was performed not in scanner mode, the correct selection of the measurement spots for the micro analysis and separation between pigments of the lower and the upper painting was of paramount importance. The described approach for spot selection was based on the results of the preceding X-radiography and digital microscopy tests. The presence of lead white, vermilion, copper green and iron earth in the underlying portrait was confirmed by the multiple point XRF analysis of Pb, Hg, Cu, Fe and Mn lines. The described investigation method proved to be useful in the identification of the pigments of the underlying painting and consequently assisted in the tentative reconstruction of its colour palette. Moreover, the undertaken approach allowed discovering the potential of micro-XRF technique in the study of hidden compositions.
NASA Astrophysics Data System (ADS)
Shizuma, Kiyoshi; Kajimoto, Tsuyoshi; Endo, Satoru; Matsugi, Kazuhiro; Arimatsu, Yui; Nojima, Hisashi
2017-09-01
Eight ancient bimetal swords held by Hiroshima University, Japan were analyzed non-destructively through γ-ray radiography and X-ray fluorescence (XRF). 137Cs and 60Co γ-ray irradiation sources were used to obtain transmission images of swords. A scanning radiography method using a 60Co γ-ray source was developed. XRF was used for qualitative elemental analysis of the swords. The presence of iron cores in the hilts of some swords had been observed and it was assumed that the cores were a ritual symbol or had a functional purpose. However, our work reveals that these swords were originally bronze-hilted iron swords and that the rusty blades were replaced with bronze blades to maintain the swords' commercial value as an antique. Consequently, the rest of the iron blade was left in the hilt as an iron tang. The junction of the blade and the guard was soldered and painted to match the patina color. XRF analysis clearly showed that the elemental Sn/Cu ratios of the blades and the hilts were different. These findings are useful for clarifying the later modifications of the swords and are important for interpreting Bronze Age and Iron Age history correctly.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Jamari, Suhailly; Embong, Zaidi; Bakar, Ismail
Electrokinetic (EK)-assisted phytoremediation is one of the methods that have a big potential in enhancing the ability of plant uptake in soils remediation process. This research was conducted to investigate the difference in elemental composition concentration of riverbank soil and the change of pH between pre- and post-phytoremediation under the following condition: 1) control or as-receive sample; 2) Dieffenbachia spp plant with EK system (a pair of EK electrodes connected to a direct current (DC) power supply). After the electrodes were connected to a magnitude of 6V/cm{sup −1} electric field for 4 hours/day, the soil and plant samples were analyzedmore » using and X-ray Fluorescence Spectrometer (XRF) and Scanning Electron Microscope / Energy Dispersive X-ray Spectroscopy (SEM/EDX). The SEM/EDX analysis showed that concentration of elemental composition (Ni, Cu and Zn) in post-phytoremediation plant powder samples had increase while elemental concentrations in the post-phytoremediation soil samples were decreased. XRF analysis presented a variation in soil elemental composition concentration from anode to cathode where the concentration near anode region increased while decreased near the cathode region. A significant changes in soil pH were obtained where the soil pH increase in cathode region while decrease in anode region. The results reveal that the assistance of EK in phytoremediation process has increase the efficiency of plant uptake.« less
Rouillon, Marek; Taylor, Mark P; Dong, Chenyin
2017-10-01
This study evaluates the in-situ use of field portable X-ray Fluorescence (pXRF) for metal-contaminated site assessments, and assesses the advantages of increased sampling to reduce risk, and increase confidence of decision making at a lower cost. Five metal-contaminated sites were assessed using both in-situ pXRF and ex-situ inductively coupled plasma mass spectrometry (ICP-MS) analyses at various sampling resolutions. Twenty second in-situ pXRF measurements of Mn, Zn and Pb were corrected using a subset of parallel ICP-MS measurements taken at each site. Field and analytical duplicates revealed sampling as the major contributor (>95% variation) to measurement uncertainties. This study shows that increased sampling led to several benefits including more representative site characterisation, higher soil-metal mapping resolution, reduced uncertainty around the site mean, and reduced sampling uncertainty. Real time pXRF data enabled efficient, on-site decision making for further judgemental sampling, without the need to return to the site. Additionally, in-situ pXRF was more cost effective than the current approach of ex-situ sampling and ICP-MS analysis, even with higher sampling at each site. Lastly, a probabilistic site assessment approach was applied to demonstrate the advantages of integrating estimated measurement uncertainties into site reporting. Copyright © 2017 Elsevier Ltd. All rights reserved.
Nondestructive Analysis of Astromaterials by Micro-CT and Micro-XRF Analysis for PET Examination
NASA Astrophysics Data System (ADS)
Zeigler, R. A.; Righter, K.; Allen, C. C.
2013-09-01
Here we discuss our recent investigations into the applications of micro-CT and micro-XRF analyses with Apollo samples and ANSMET meteorites and assess the usefulness of these techniques in future PET.
NASA Astrophysics Data System (ADS)
Silva, Marina Piacenti da; Silva, Deisy Mara da; Ribeiro-Silva, Alfredo; Poletti, Martin Eduardo
2012-05-01
The aim of this work is to investigate microscopic correlations between trace elements in breast human tissues. A synchrotron X-ray fluorescence microprobe system (μ-XRF) was used to obtain two-dimensional distribution of trace element Ca, Fe, Cu and Zn in normal (6 samples) and malignant (14 samples) breast tissues. The experiment was performed in X-ray Fluorescence beam line at Laboratório Nacional de Luz Síncrotron (LNLS), Campinas, Brazil. The white microbeam was generated with a fine conical capillary with a 20 μm output diameter. The samples were supported on a XYZ table. An optical microscope with motorized zoom was used for sample positioning and choice the area to be scanned. Automatic two-dimensional scans were programmed and performed with steps of 30 μm in each direction (x, y) on the selected area. The fluorescence signals were recorded using a Si(Li) detector, positioned at 90 degrees with respect to the incident beam, with a collection time of 10 s per point. The elemental maps obtained from each sample were overlap to observe correlation between trace elements. Qualitative results showed that the pairs of elements Ca-Zn and Fe-Cu could to be correlated in malignant breast tissues. Quantitative results, achieved by Spearman correlation tests, indicate that there is a spatial correlation between these pairs of elements (p < 0.001) suggesting the importance of these elements in metabolic processes associated with the development of the tumor.
NASA Astrophysics Data System (ADS)
Williams, J. N.; Toy, V.; Massiot, C.; Mcnamara, D. D.; Wang, T.
2015-12-01
X-ray computer tomography (CT) scans of core recovered from the first phase of the Deep Fault Drilling Project (DFDP-1) through the Alpine Fault provide an excellent opportunity to analyse brittle deformation around the fault. In particular, assessment can be made of the heavily fractured protolith constituting the damage zone. Damage zone structures are divided into two types that result from two distinct processes: (1) "off fault damage" formed by stress changes induced by the passage of a seismic rupture and (2) "off fault deformation" that represent structures, which accommodate strain around the fault that was not localised on the principal slip zone (PSZ). The distribution of these damage zones structures within CT scans of the recovered core was measured along a scanline parallel to the core axis and assessed using a weighted moving average technique to account for orientation bias. The results of this analysis reveal that within the part of the fault rocks sampled by DFDP-1 there is no increase in density of these structures towards the PSZ. This is in agreement with independent analysis using Borehole Televiewer Data of the DFDP-1B borehole. Instead, we consider the density of these structures to be controlled to the first order by lithology, which modulates the mechanical properties of the fault rocks such as its frictional strength and cohesion. Comparisons of fracture density to p-wave velocities obtained from wireline logs indicate they are independent of each other, therefore, for the cores sampled in this study fractures impart no influence on the elastic properties of the rock. This is consistent with the observation from core that the majority of fractures are cemented. We consider how this might influence future rupture dynamics.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Masson, D.G.; Huggett, Q.J.; Weaver, P.P.E.
1991-08-01
Side-scan sonar data, cores, and high-resolution profiles have been used to produce an integrated model of sedimentation for the continental margin west of the Canary Islands. Long-range side-scan sonar (GLORIA) data and a grid of 3.5-kHz profiles, covering some 200,000 km{sup 2} allow a regional appraisal of sedimentation. More detailed studies of selected areas have been undertaken using a new 30 kHz deep-towed side-scan sonar (TOBI) developed by the U.K. Institute of Oceanographic Sciences. Sediment cores have been used both to calibrate acoustic facies identified on sonographs and for detailed stratigraphic studies. The most recent significant sedimentation event in themore » area is to Saharan Sediment Slide, which carried material from the upper continental slope off West Africa to the edge of the Madeira Abyssal Plain, a distance of some 1000 km. The authors data shows the downslope evolution of the debris flow. Near the Canaries, it is a 20-m-thick deposit rafting coherent blocks of more than 1 km diameter; side-scan records show a strong flow-parallel fabric on a scale of tens of meters. On the lower slope, the debris flow thins to a few meters, the flow fabric disappears, and the rafted blocks decrease to meters in diameter. Side-scan data from the lower slope show that the Saharan Slide buries an older landscape of turbidity current channels, typically 1 km wide and 50 m deep. Evidence from the Madeiran Abyssal Plain indicates a history of large but infrequent turbidity currents, the emplacement of which is related to the effects of sea level changes on the northwest African margin.« less
NASA Astrophysics Data System (ADS)
Park, Seunghoon; Joung, Sungyeop; Park, Jerry AB(; ), AC(; )
2018-01-01
Assay of L-series of nuclear material solution is useful for determination of amount of nuclear materials and ratio of minor actinide in the materials. The hybrid system of energy dispersive X-ray absorption edge spectrometry, i.e. L-edge densitometry, and X-ray fluorescence spectrometry is one of the analysis methods. The hybrid L-edge/XRF densitometer can be a promising candidate for a portable and compact equipment due to advantage of using low energy X-ray beams without heavy shielding systems and liquid nitrogen cooling compared to hybrid K-edge/XRF densitometer. A prototype of the equipment was evaluated for feasibility of the nuclear material assay using a surrogate material (lead) to avoid radiation effects from nuclear materials. The uncertainty of L-edge and XRF characteristics of the sample material and volume effects was discussed in the article.
XRF measurements of tin, copper and zinc in antifouling paints coated on leisure boats.
Ytreberg, Erik; Bighiu, Maria Alexandra; Lundgren, Lennart; Eklund, Britta
2016-06-01
Tributyltin (TBT) and other organotin compounds have been restricted for use on leisure boats since 1989 in the EU. Nonetheless, release of TBT is observed from leisure boats during hull maintenance work, such as pressure hosing. In this work, we used a handheld X-ray Fluorescence analyser (XRF) calibrated for antifouling paint matrixes to measure tin, copper and zinc in antifouling paints coated on leisure boats in Sweden. Our results show that over 10% of the leisure boats (n = 686) contain >400 μg/cm(2) of tin in their antifouling coatings. For comparison, one layer (40 μm dry film) of a TBT-paint equals ≈ 800 μg Sn/cm(2). To our knowledge, tin has never been used in other forms than organotin (OT) in antifouling paints. Thus, even though the XRF analysis does not provide any information on the speciation of tin, the high concentrations indicate that these leisure boats still have OT coatings present on their hull. On several leisure boats we performed additional XRF measurements by progressively scraping off the top coatings and analysing each underlying layer. The XRF data show that when tin is detected, it is most likely present in coatings close to the hull with several layers of other coatings on top. Thus, leaching of OT compounds from the hull into the water is presumed to be negligible. The risk for environmental impacts arises during maintenance work such as scraping, blasting and high pressure hosing activities. The data also show that many boat owners apply excessive paint layers when following paint manufacturers recommendations. Moreover, high loads of copper were detected even on boats sailing in freshwater, despite the more than 20 year old ban, which poses an environmental risk that has not been addressed until now. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.
A new high-resolution sediment record from Lake Gościąż (central Poland)
NASA Astrophysics Data System (ADS)
Bonk, Alicja; Błaszkiewicz, Mirosław; Brauer, Achim; Brykała, Dariusz; Gierszewski, Piotr; Kramkowski, Mateusz; Plessen, Brigit; Schwab, Markus; Słowiński, Michał; Tjallingii, Rik
2017-04-01
The varved sediments from Lake Gościąż, located in the Vistula Valley in Central Poland, are an iconic record for palaeoclimate and palaeoenvironmental reconstruction (Goslar et al. 2000, Hajdas et al. 1995, Ralska-Jasiewiczowa et al. 1998). Recently, we obtained a set of new sediment cores from Lake Gościąż and established a 21 m long sediment profile. Except of the topmost part of the core, it is continuously laminated down to glacial sands. We aim at applying a comprehensive multi-proxy core analyses combined with monitoring of present-day sedimentation processes. Sediment investigations will include new methods that have been developed or advanced since the previous studies on the Lake Gościąż sediments including continuous micro-facies analyses, μXRF core scanning and tephrochronology. The main aims of our new project are a revision of the existing floating chronology and to synchronise the Lake Gościąż sediment record based on independent isochrones with other European varved lake records like, e.g. Lake Meerfelder Maar, in order to investigate in detail proxy responses to climate change and to decipher regional leads and lags in climate change. Here, we will present (1) the objectives of our new project on this key record of past climate and environmental change and, (2) preliminary results including magnetic susceptibility, μ-XRF core scanning and microfacies images. This study is a contribution to scientific project financed by the National Science Centre, Poland - No DEC-2015/19/B/ST10/03039.
Denecke, Melissa A; Somogyi, Andrea; Janssens, Koen; Simon, Rolf; Dardenne, Kathy; Noseck, Ulrich
2007-06-01
Micro-focused synchrotron radiation techniques to investigate actinide elements in geological samples are becoming an increasingly used tool in nuclear waste disposal research. In this article, results using mu-focus techniques are presented from a bore core section of a U-rich tertiary sediment collected from Ruprechtov, Czech Republic, a natural analog to nuclear waste repository scenarios in deep geological formations. Different methods are applied to obtain various, complementary information. Elemental and element chemical state distributions are obtained from micro-XRF measurements, oxidation states of As determined from micro-XANES, and the crystalline structure of selected regions are studied by means of micro-XRD. We find that preparation of the thin section created an As oxidation state artifact; it apparently changed the As valence in some regions of the sample. Results support our previously proposed hypothesis of the mechanism for U-enrichment in the sediment. AsFeS coating on framboid Fe nodules in the sediment reduced mobile groundwater-dissolved U(VI) to less-soluble U(IV), thereby immobilizing the uranium in the sediment.
Elemental Scanning Devices Authenticate Works of Art
NASA Technical Reports Server (NTRS)
2013-01-01
To better detect aluminum compounds, Marshall Space Flight Center partnered with KeyMaster Inc. (later acquired by Madison, Wisconsin-based Bruker AXS Inc.) to develop a vacuum pump system that could be attached to X-ray fluorescence (XRF) scanners. The resulting technology greatly expanded XRF scanner capabilities, and hundreds of museums now use them to authenticate artifacts and works of art.
XRF inductive bead fusion and PLC based control system
NASA Astrophysics Data System (ADS)
Zhu, Jin-hong; Wang, Ying-jie; Shi, Hong-xin; Chen, Qing-ling; Chen, Yu-xi
2009-03-01
In order to ensure high-quality X-ray fluorescence spectrometry (XRF) analysis, an inductive bead fusion machine was developed. The prototype consists of super-audio IGBT induction heating power supply, rotation and swing mechanisms, and programmable logic controller (PLC). The system can realize sequence control, mechanical movement control, output current and temperature control. Experimental results show that the power supply can operate at an ideal quasi-resonant state, in which the expected power output and the required temperature can be achieved for rapid heating and the uniform formation of glass beads respectively.
NASA Astrophysics Data System (ADS)
Suwanich, Parkorn
Clay-mineral assemblages in Middle Clastic, Middle Salt, Lower Clastic, Potash Zone, and Lower Salt, totalling 13 samples from K-118 drill core, in the Maha Sarakham Formation, Khorat Basin, northeastern Thailand were studied. The clay-size particles were separated from the water-soluble salt by water leaching. Then the samples were leached again in the EDTA solution and separated into clay-size particles by using the timing sedimentation. The EDTA-clay residues were divided and analyzed by using the XRD and XRF method. The XRD peaks show that the major-clay minerals are chlorite, illite, and mixed-layer corrensite including traces of rectorite? and paragonite? The other clay-size particles are quartz and potassium feldspar. The XRF results indicate Mg-rich values and moderate MgAl atom ratio values in those clay minerals. The variable Fe, Na, and K contents in the clay-mineral assemblages can explain the environment of deposition compared to the positions of the samples from the core. Hypothetically, mineralogy and the chemistry of the residual assemblages strongly indicate that severe alteration and Mg-enrichment of normal clay detritus occurred in the evaporite environment through brine-sediment interaction. The various Mg-enrichment varies along the various members reflecting whether sedimentation is near or far from the hypersaline brine.
Koralay, Tamer; Kadioglu, Yusuf Kagan
2008-03-01
Medium to large volume ignimbrites usually show vertical changes in terms of color, mineral components, texture and geochemistry. Determination of vertical changes in single extensive ignimbrite flow unit is difficult and requires careful studies. Color changes in ignimbrite flow units are very important for earth scientists. This may cause to identify the same ignimbrite series with different definition. Incesu ignimbrite has a wide distribution in the Central Anatolian Volcanic Province (CAVP). It is classified into three levels as lower, middle and upper according to color and welding degree. There is a sharp contact between the lower and middle level. The lower level is dark brown to black in color and the middle level has pinkish red to red color. The present paper focuses on the investigation of color changes between the ignimbrite levels by using micro-XRF and confocal Raman spectrometry. Micro-XRF and Raman spectrometry studies were performed on the polished thin sections of the lower and middle levels with different compositions. These differences were because of the compositional changes of K and slightly Fe elements distribution within the matrix. The dark brown to black color of the lower level was related to the high concentration of the K and Fe relatively to the middle level. Confocal Raman spectrometry investigations exhibited the matrix of the lower level mainly composed of anorthoclase, supporting the results of the micro-XRF.
NASA Astrophysics Data System (ADS)
Jamaluddin; Darwis, A.; Massinai, M. A.
2018-02-01
Asbuton as natural rock asphalt consists of a granular material; usually limestone or sandstone. In its natural state, it contains bitumen intimately dispersed throughout its mass, while the remainder of the material is a solid mineral matter. This research was conducted in Sorowalio, Buton Regency, Southeast Sulawesi province, Indonesia. This study aims to determine the content and the percentage of minerals contained in the rocks by using X-Ray Fluorescence (XRF). The method of research is a preliminary survey, sampling and laboratory analysis. XRF reports chemical composition, including Si (quartz) and Ca (calcite). The results indicate the content and the percentage of element dominate the rock sample is Fe2O3, MgO, CaO, and SiO2. Research results using XRF show that there are four metal oxide dominant elements. Hematite (Fe2O3) is dominant in all locations of sampling. Magnesium oxide (MgO) has the highest levels found in sample number six and the lowest is in sample number five. Silicates (SiO) has the highest levels at sample number six and the lowest in sample number seven. Calcium oxide (CaO) is dominant in all sampling locations. The sample of asbuton contains 37.90% asphalt, 43.28% carbonate, and18.82% other minerals.
Online sorting of recovered wood waste by automated XRF-technology: part II. Sorting efficiencies.
Hasan, A Rasem; Solo-Gabriele, Helena; Townsend, Timothy
2011-04-01
Sorting of waste wood is an important process practiced at recycling facilities in order to detect and divert contaminants from recycled wood products. Contaminants of concern include arsenic, chromium and copper found in chemically preserved wood. The objective of this research was to evaluate the sorting efficiencies of both treated and untreated parts of the wood waste stream, and metal (As, Cr and Cu) mass recoveries by the use of automated X-ray fluorescence (XRF) systems. A full-scale system was used for experimentation. This unit consisted of an XRF-detection chamber mounted on the top of a conveyor and a pneumatic slide-way diverter which sorted wood into presumed treated and presumed untreated piles. A randomized block design was used to evaluate the operational conveyance parameters of the system, including wood feed rate and conveyor belt speed. Results indicated that online sorting efficiencies of waste wood by XRF technology were high based on number and weight of pieces (70-87% and 75-92% for treated wood and 66-97% and 68-96% for untreated wood, respectively). These sorting efficiencies achieved mass recovery for metals of 81-99% for As, 75-95% for Cu and 82-99% of Cr. The incorrect sorting of wood was attributed almost equally to deficiencies in the detection and conveyance/diversion systems. Even with its deficiencies, the system was capable of producing a recyclable portion that met residential soil quality levels established for Florida, for an infeed that contained 5% of treated wood. Copyright © 2010 Elsevier Ltd. All rights reserved.
Use of small volume cups in XRF analysis of treated wood retention
Rene Stelzer; Adam Taylor; Patricia Lebow
2017-01-01
Efforts are underway in the United States to improve the conformance of commercially-treated wood with the applicable retention standards. As part of an effort to devise a practical method for on-site assessment of within-charge retention variation, we investigated whether small-volume x-ray fluorescence (XRF) sample cups could be used with treated wood. A range of cup...
An Integrated XRF/XRD Instrument for Mars Exobiology and Geology Experiments
NASA Technical Reports Server (NTRS)
Koppel, L. N.; Franco, E. D.; Kerner, J. A.; Fonda, M. L.; Schwartz, D. E.; Marshall, J. R.
1993-01-01
By employing an integrated x-ray instrument on a future Mars mission, data obtained will greatly augment those returned by Viking; details characterizing the past and present environment on Mars and those relevant to the possibility of the origin and evolution of life will be acquired. A combined x-ray fluorescence/x-ray diffraction (XRF/XRD) instrument was breadboarded and demonstrated to accommodate important exobiology and geology experiment objectives outlined for MESUR and future Mars missions. Among others, primary objectives for the exploration of Mars include the intense study of local areas on Mars to establish the chemical, mineralogical, and petrological character of different components of the surface material; to determine the distribution, abundance, and sources and sinks of volatile materials, including an assessment of the biologic potential, now and during past epoches; and to establish the global chemical and physical characteristics of the Martian surface. The XRF/XRD breadboard instrument identifies and quantifies soil surface elemental, mineralogical, and petrological characteristics and acquires data necessary to address questions on volatile abundance and distribution. Additionally, the breadboard is able to characterize the biogenic element constituents of soil samples providing information on the biologic potential of the Mars environment. Preliminary breadboard experiments confirmed the fundamental instrument design approach and measurement performance.
NASA Astrophysics Data System (ADS)
Peros, Matthew; Collins, Shawn; G'Meiner, Anna Agosta; Reinhardt, Eduard; Pupo, Felipe Matos
2017-07-01
We use sediments from a flooded sinkhole (Cenote Jennifer) in northern Cuba to provide new, well-dated, high-resolution evidence for the 8.2 kyr event. From 7600 to 8700 cal yr B.P. the sinkhole contained shallow, low-salinity water, which supported a marsh dominated by cattail and grass. Peaks in Cl and Br—occurring at 8150, 8200, and 8250 cal yr B.P.—are attributable to increased evaporation due to regional drying associated with the 8.2 kyr event. The three peaks in these elements also closely correspond to the greyscale record from the Cariaco Basin, indicative of increased upwelling in the southern Caribbean Sea at this time, supporting the notion of a multistage 8.2 kyr event. Our work provides new data that help to clarify the initiation, behavior, and impacts of the 8.2 kyr event in the northern tropics.
NASA Astrophysics Data System (ADS)
Ranasinghage, P. N.; Nanayakkara, N. U.; Kodithuwakku, S.; Siriwardana, S.; Luo, C.; Fenghua, Z.
2016-12-01
Indian monsoon plays a vital role in determining climate events happening in the Asian region. There is no sufficient work in Sri Lanka to fully understand how the summer monsoonal variability affected Sri Lanka during the quaternary. Sri Lanka is situated at an ideal location with a unique geography to isolate Indian summer monsoon record from iris counterpart, Indian winter monsoon. Therefore, this study was carried out to investigate its variability and understand the forcing factors. For this purpose a 1.82 m long gravity core, extracted from western continental shelf off Colombo, Sri Lanka by Shiyan 1 research vessel, was used. Particle size, chemical composition and colour reflectance were measured using laser particle size analyzer at 2 cm resolution, X-Ray Fluorescence spectrometer (XRF) at 2 cm resolution, and color spectrophotometer at 1 cm resolution respectively. Radio carbon dating of foraminifera tests by gas bench technique yielded the sediment age. Finally, principal component analysis (PCA) of XRF and color reflectance (DSR) data was performed to identify groups of correlating elements and mineralogical composition of sediments. Particle size results indicate that Increasing temperature and strengthening monsoonal rainfall after around 18000 yrs BP, at the end of last glacial period, enhanced chemical weathering over physical weathering. Proxies for terrestrial influx (XRF PC1, DSR PC1) and upwelling and nutrient supply driven marine productivity (XRF PC3 and DSR PC2) indicate that strengthening of summer monsoon started around 15000 yrs BP and maximized around 8000-10000 yrs BP after a short period of weakening during Younger Dryas (around 11000 yrs BP). The 8.2 cold event was recorded as a period of low terrestrial influx indicating weakening of rainfall. After that terrestrial input was low till around 2000 yrs BP indicating decrease in rainfall. However, marine productivity remained increasing throughout the Holocene indicating an increase in
Geochemistry records from laminated sediments of Shira Lake (Russian Asia)
NASA Astrophysics Data System (ADS)
Phedorin, M.; Vologina, E.; Drebuschak, M.; Tolomeev, A.; Kirichenko, I.; Toyabin, A.
2009-04-01
We measured downcore elements distributions in five cores collected across the Shira Lake situated in Central part of Asia (E90o12', N54o30'). The lake is small (32km2), saline (ca.20g/l SO4-, Cl-, Na+, Mg+, K+), being filled with regional precipitation of about 300mm/year (mainly through one major tributary, river Son) and has no surface outflow. The aim of our study was to reconstruct history of changes in the regime of the lake that happened both before and during period of instrumental meteorological observations. In particular, we were interested in lake-level changes due to evaporation, water supply from surface and from underground sources, and in changes of bioproduction in the lake as well. To construct depth-age model for the cores, we measured Cs-137 and unsupported Pb-210 in top layers of the cores. The sedimentation rate thus identified varied in the range of 1-2 mm/year for different cores. We visually observed fine sedimentation ‘rhythms' having thickness of about 0.x-2.x mm: these layers may now be reliably identified as annual lamination. We also determined concentrations of elements in the sediments by recording x-ray fluorescence (XRF) spectra when continuously scanning the halves of the cores under sharp synchrotron radiation (SR) beam, using an instrument described in (Zolotarev et al., 2001). The resolution of the scanning was 0.1 mm. After processing of the measured XRF-SR data as in (Phedorin and Goldberg, 2005) we obtained downcore records of 20 elements. We correlated all five cores employing elements patterns. We qualitatively identified variations in surface-water supply treating markers of ‘clastic' material (Ti, Rb, Zr). We identified downcore variations in authgenic mineralization, which appeared to have different kinds: Ca-related, Sr-related, Ba-related, Fe-related. We tried to assess biogenic production changes from Br distribution, admitting analogy of Br in Shira sediments to Br in Lake Baikal sediments (Phedorin et al., 2000
A High Rigidity and Precision Scanning Tunneling Microscope with Decoupled XY and Z Scans
Chen, Xu; Guo, Tengfei; Hou, Yubin; Zhang, Jing
2017-01-01
A new scan-head structure for the scanning tunneling microscope (STM) is proposed, featuring high scan precision and rigidity. The core structure consists of a piezoelectric tube scanner of quadrant type (for XY scans) coaxially housed in a piezoelectric tube with single inner and outer electrodes (for Z scan). They are fixed at one end (called common end). A hollow tantalum shaft is coaxially housed in the XY-scan tube and they are mutually fixed at both ends. When the XY scanner scans, its free end will bring the shaft to scan and the tip which is coaxially inserted in the shaft at the common end will scan a smaller area if the tip protrudes short enough from the common end. The decoupled XY and Z scans are desired for less image distortion and the mechanically reduced scan range has the superiority of reducing the impact of the background electronic noise on the scanner and enhancing the tip positioning precision. High quality atomic resolution images are also shown. PMID:29270242
A High Rigidity and Precision Scanning Tunneling Microscope with Decoupled XY and Z Scans.
Chen, Xu; Guo, Tengfei; Hou, Yubin; Zhang, Jing; Meng, Wenjie; Lu, Qingyou
2017-01-01
A new scan-head structure for the scanning tunneling microscope (STM) is proposed, featuring high scan precision and rigidity. The core structure consists of a piezoelectric tube scanner of quadrant type (for XY scans) coaxially housed in a piezoelectric tube with single inner and outer electrodes (for Z scan). They are fixed at one end (called common end). A hollow tantalum shaft is coaxially housed in the XY -scan tube and they are mutually fixed at both ends. When the XY scanner scans, its free end will bring the shaft to scan and the tip which is coaxially inserted in the shaft at the common end will scan a smaller area if the tip protrudes short enough from the common end. The decoupled XY and Z scans are desired for less image distortion and the mechanically reduced scan range has the superiority of reducing the impact of the background electronic noise on the scanner and enhancing the tip positioning precision. High quality atomic resolution images are also shown.
NASA Astrophysics Data System (ADS)
Ergenç, Duygu; Freire, David; Fort, Rafael
2016-04-01
The chemical characterization of lime mortars used in Roman period has a great significance and plays a key role in the acquisition of knowledge with respect to construction technology, raw materials and, accordingly, in its conservation works. When it comes to cultural heritage studies, sampling is always complicated since the minimum damage is the primary concern. The use of non-destructive techniques and direct measurements with portable devices reduce the amount of samples and time consumed in analyses, consequently it could be stated that such techniques are extremely useful in conservation and restoration works. In this study, the portable XRF device was used to determine the composition of chemical elements which compose the Roman lime mortars in the archaeological site of Complutum, Alcalá de Henares (Madrid, Spain) which is listed as a World Heritage Site by UNESCO since 1998. Portable XRF devices have some detection limits below the ones of the laboratory equipment that are immovable and require sampling. In order to correlate the results, sampling and grinding were initially done to prepare the powders for the laboratory XRF analysis with the following elements: Si, Al, Fe, Ca, Mg, K, Ti, Nb, Zr, Sr, Rb, Pb, Zn and Cr. The analyses of the powdered samples were conducted with the laboratory equipment PHILIPS Magix Pro (PW-2440) from the Centre of Scientific Instrumentation CIC in the University of Granada, and the results were compared to the results gathered with X Ray Florescence (EDTRX) THERMO NITON model XL3T from the Petrophysics Laboratory Geosciences Institute IGEO (CSIC-UCM). Analyses were performed on the surfaces of the samples -without any previous preparation-, and on the powdered samples to compare the variations between both traditional XRF analyses and the portable XRF. A good correlation was found among the results obtained by the laboratory equipment, the portable device as well as the surface measurements. The results of this study
NASA Astrophysics Data System (ADS)
Chiari, M.; Yubero, E.; Calzolai, G.; Lucarelli, F.; Crespo, J.; Galindo, N.; Nicolás, J. F.; Giannoni, M.; Nava, S.
2018-02-01
Within the framework of research projects focusing on the sampling and analysis of airborne particulate matter, Particle Induced X-ray Emission (PIXE) and Energy Dispersive X-ray Fluorescence (ED-XRF) techniques are routinely used in many laboratories throughout the world to determine the elemental concentration of the particulate matter samples. In this work an inter-laboratory comparison of the results obtained from analysing several samples (collected on both Teflon and quartz fibre filters) using both techniques is presented. The samples were analysed by PIXE (in Florence, at the 3 MV Tandetron accelerator of INFN-LABEC laboratory) and by XRF (in Elche, using the ARL Quant'X EDXRF spectrometer with specific conditions optimized for specific groups of elements). The results from the two sets of measurements are in good agreement for all the analysed samples, thus validating the use of the ARL Quant'X EDXRF spectrometer and the selected measurement protocol for the analysis of aerosol samples. Moreover, thanks to the comparison of PIXE and XRF results on Teflon and quartz fibre filters, possible self-absorption effects due to the penetration of the aerosol particles inside the quartz fibre-filters were quantified.
Jaswal, Brij Bir S; Kumar, Vinay; Sharma, Jitendra; Rai, Pradeep K; Gondal, Mohammed A; Gondal, Bilal; Singh, Vivek K
2016-04-01
Laser-induced breakdown spectroscopy (LIBS) is an emerging analytical technique with numerous advantages such as rapidity, multi-elemental analysis, no specific sample preparation requirements, non-destructiveness, and versatility. It has been proven to be a robust elemental analysis tool attracting interest because of being applied to a wide range of materials including biomaterials. In this paper, we have performed spectroscopic studies on gallstones which are heterogeneous in nature using LIBS and wavelength dispersive X-ray fluorescence (WD-XRF) techniques. It has been observed that the presence and relative concentrations of trace elements in different kind of gallstones (cholesterol and pigment gallstones) can easily be determined using LIBS technique. From the experiments carried out on gallstones for trace elemental mapping and detection, it was found that LIBS is a robust tool for such biomedical applications. The stone samples studied in the present paper were classified using the Fourier transform infrared (FTIR) spectroscopy. WD-XRF spectroscopy has been applied for the qualitative and quantitative analysis of major and trace elements present in the gallstone which was compared with the LIBS data. The results obtained in the present paper show interesting prospects for LIBS and WD-XRF to study cholelithiasis better.
Study of CT Scan Flooding System at High Temperature and Pressure
NASA Astrophysics Data System (ADS)
Chen, X. Y.
2017-12-01
CT scan flooding experiment can scan micro-pore in different flooding stages by the use of CT scan technology, without changing the external morphology and internal structure of the core, and observe the distribution characterization in pore medium of different flooding fluid under different pressure.thus,it can rebuilt the distribution images of oil-water distribution in different flooding stages. However,under extreme high pressure and temperature conditions,the CT scan system can not meet the requirements. Container of low density materials or thin shell can not resist high pressure,while high density materials or thick shell will cause attenuation and scattering of X-ray. The experiment uses a simple Ct scanning systems.X ray from a point light source passing trough a micro beryllium shell on High pressure stainless steal container,continuously irradiates the core holder that can continuously 360° rotate along the core axis. A rare earth intensifying screen behind the core holder emitting light when irradiated with X ray can show the core X ray section image. An optical camera record the core X ray images through a transparency high pressure glazing that placed on the High pressure stainless steal container.Thus,multiple core X ray section images can reconstruct the 3D core reconstruction after a series of data processing.The experiment shows that both the micro beryllium shell and rare earth intensifying screen can work in high temperature and high pressure environment in the stainless steal container. This way that X-ray passes through a thin layer of micro beryllium shell , not high pressure stainless steal shell,avoid the attenuation and scattering of X-ray from the container shell,while improving the high-pressure experiment requirements.
High resolution analysis of northern Patagonia lake sediments
NASA Astrophysics Data System (ADS)
Jarvis, S. W.; Croudace, I. W.; Langdon, P. G.; Rindby, A.
2009-04-01
Sediment cores covering the period from the last glacial maximum through the Holocene to the present have been collected from sites in the Chacubuco valley, southern Chile (around 47°08'S, 72°25'W, to the east of the North Patagonian Icecap). Cores were taken from five lakes and one recently dried lake bed. Short cores (0.2 to 0.5m), covering approximately the last two hundred years, were taken from all the lakes. Additionally, long sequences were obtained from one of the lakes and from the dried lake bed, the latter sequence extending back to the last glacial maximum as indicated by thick clay at the base. Each of the lakes are small-medium sized and are open systems situated at 300-1000m above sea level. The shorter cores comprise predominantly clastic gyttja but show a number of distinct changes in colour and chemical composition that suggest major environmental changes over the period of sediment accumulation. This is also reflected in variations in the loss on ignition of samples from the cores and in elemental profiles produced by scanning the cores with the Itrax micro-XRF corescanner at 200μm resolution. The long sequence from the dried lake bed has very low organic content glacial clay at the base, interpreted as last glacial maximum basal clay following determination in the field that this layer exceeded 2m in thickness. Similar sediments occur within a stratigraphically discrete section of approximately 14cm and may relate to a stadial event. The latter section also shows a drop in organic content and appears to be glacial clay incorporating some coarse sandy components indicative of detrital input from the catchment. The second long sequence, from a carbonate lake, includes two mineral layers indicating increased detrital input from the catchment. The deeper and thicker of these layers appears similar to the 14cm layer in the first long sequence, while the upper layer comprises a fine grain size indicative of rock flour and hence also of glacial
Paleoseismic events inferred from marine seismogenic turbidites of the eastern Nankai Trough
NASA Astrophysics Data System (ADS)
Okutsu, N.; Ashi, J.; Omura, A.; Yamaguchi, A.; Suganuma, Y.; Kanamatsu, T.; Murayama, M.
2016-12-01
Paleoseismology using marine seismogenic turbidites is a developing field especially in subduction margins. However, very fine-grained turbidites are difficult to distinguish from hemipelagic mud. The primary focus of this study is to understand the characteristics of the muddy turbidites. The second focus is to discuss the muddy turbidites distributions and their ages from a longer sediment core, and understand the paleoseismic records of eastern Nankai Trough, Japan. The samples used in this study include multiple cores and a piston core which were collected from the sedimentary basin southwest off Kii Peninsula during the R/V Shinsei Maru KS-14-8 cruise. The sampling site is located at the ENE-WSW elongated basin between the accretionary prism and the forearc basin off Kumano without terrestrial sediment supply. The basin exhibits a terminal basin that captures all sediments supplied from outside. From the multiple core samples, the Cs-137 and Pb- 210 concentration distribution indicates that the muddy sediment layer in the upper 17 cm was formed from the 2004 off the Kii Peninsula earthquake. Visual observation and X-ray CT scans were conducted alongside other measurements for anisotropy of magnetic susceptibility (AMS), paleomagnetism, rock magnetism, electrical resistivity, and X-ray fluorescence core scanning (XRF). Muddy seismogenic turbidites associated with the 2004 off the Kii Peninsula earthquake have thick homogeneous clay layer above the silty lamination. The magnetic susceptibility decreases upwards in the lamination. This specific feature is thought to have formed as the muddy turbiditity current slowly decelerated and slowly settled down the slope. From the results of XRF core scanning, Ca and Fe have a peak at basement of turbidites, and decrease upwards. Ca is thought to correspond to amount of the foraminiferas. In piston core, we observed the same sedimentary and magnetic characteristics as the multiple cores. Based on stratigraphic information
NASA Astrophysics Data System (ADS)
Rouillon, M.; Taylor, M. P.; Dong, C.
2016-12-01
This research assesses the advantages of integrating field portable X-ray Fluorescence (pXRF) technology for reducing the risk and increase confidence of decision making for metal-contaminated site assessments. Metal-contaminated sites are often highly heterogeneous and require a high sampling density to accurately characterize the distribution and concentration of contaminants. The current regulatory assessment approaches rely on a small number of samples processed using standard wet-chemistry methods. In New South Wales (NSW), Australia, the current notification trigger for characterizing metal-contaminated sites require the upper 95% confidence interval of the site mean to equal or exceed the relevant guidelines. The method's low `minimum' sampling requirements can misclassify sites due to the heterogeneous nature of soil contamination, leading to inaccurate decision making. To address this issue, we propose integrating infield pXRF analysis with the established sampling method to overcome sampling limitations. This approach increases the minimum sampling resolution and reduces the 95% CI of the site mean. Infield pXRF analysis at contamination hotspots enhances sample resolution efficiently and without the need to return to the site. In this study, the current and proposed pXRF site assessment methods are compared at five heterogeneous metal-contaminated sites by analysing the spatial distribution of contaminants, 95% confidence intervals of site means, and the sampling and analysis uncertainty associated with each method. Finally, an analysis of costs associated with both the current and proposed methods is presented to demonstrate the advantages of incorporating pXRF into metal-contaminated site assessments. The data shows that pXRF integrated site assessments allows for faster, cost-efficient, characterisation of metal-contaminated sites with greater confidence for decision making.
NASA Astrophysics Data System (ADS)
Geissman, J. W.; Olsen, P. E.; Kent, D. V.; Irmis, R. B.; Gehrels, G. E.; Mundil, R.; Parker, W.; Bachmann, G. H.; Kurschner, W. M.; Sha, J.
2014-12-01
The Triassic Period was punctuated by two of the largest Phanerozoic mass-extinctions and witnessed the evolution of elements of the modern biota and the advent of the age of dinosaurs. A rich archive of biotic and environmental changes on land for the early Mesozoic is on the Colorado Plateau, which despite over 100 years of study still remains poorly calibrated in time and poorly registered to other global records. Over 15 years ago, a diverse team of scientists began to develop the concept of a multi-phase, long term Colorado Plateau Coring Project (CPCP). Planning involved two major meetings (DOSECC/NSFICDP supported in Fall, 2007, St. George, UT; and International Continental Drilling Program (ICDP) supported in Spring, 2009, Albuquerque, NM). The National Park Service embraced the concept of Phase One drilling at Petrified Forest National Park (PFNP) in northern Arizona, which exposes one of the most famous and best studied successions of the continental Triassic on Earth, and the Phase One target was decided. Most drilling operation costs were secured from ICDP in Summer, 2010. In late 2013, following more recent NSF support, the research team, utilizing Ruen Drilling Inc., drilled a continuous ~530 m core (60o plunge) through the entire section of Triassic strata (Chinle and Moenkopi fms.) in the north end and a ~240 m core (75o plunge) in lower Chinle and all Moenkopi strata at the south end of the PFNP. Our continuous sampling will place this record in a reliable quantitative and exportable time scale, as a reference section in which magnetostratigraphic, geochronologic, environmental, and paleontologic data are registered to a common thickness scale with unambiguous superposition using pristine samples. The cores are being scanned at the High Resolution X-ray Computed Tomography Facility at UT Austin. They will be transported to the LacCore National Lacustrine Core Facility at U Minnesota, where they will be split, imaged, and scanned for several
Specht, Aaron J; Lin, Yanfen; Weisskopf, Marc; Yan, Chonghuai; Hu, Howard; Xu, Jian; Nie, Linda H
2016-01-01
Childhood lead (Pb) poisoning remains a global issue, especially in industrial areas. In this study, 115 children with average age 5.7 years were recruited as either patient diagnosed with Pb poisoning or controls at Xinhua Hospital in China. The subjects' bone Pb was measured with a K-shell X-ray fluorescence (KXRF) and a portable X-ray fluorescence (XRF) system. A significant correlation between KXRF bone Pb and blood Pb and portable XRF and KXRF measurements were observed. The half-life of blood-lead was calculated to be 9.96 ± 3.92 d. Our results indicate that bone is a useful biomarker for Pb in children.
NASA Astrophysics Data System (ADS)
Curti, Enzo; Dähn, Rainer; Farges, François; Vespa, Marika
2009-04-01
Microscopic distribution and speciation of Na, Mg, Ni and Cs in a simulated (inactive) nuclear waste glass were studied using micro X-ray fluorescence (μ-XRF) and micro X-ray absorption spectroscopy (μ-XAS), after aqueous leaching during 12 years at 90 °C. Na and Mg are major constituents of the glass that can be used to determine the progress of the glass corrosion process and the nature of secondary alteration phases. Ni and Cs represent dose determining long-lived radionuclides ( 59Ni, 135Cs) in vitrified nuclear waste. The Na-Mg μ-XRF maps revealed that the core regions of the glass fragments are apparently unaltered and compositionally homogeneous, whereas rims and interstitial spaces are enriched with Mg-rich smectite formed during the leaching process. The micro X-ray absorption near edge structure (μ-XANES) spectra collected at the Mg K-edge in the altered zones show three sharp resonances typical for crystalline Mg-silicates. These resonances are distinctive of Mg occupying undistorted octahedral positions. In contrast, the μ-XANES spectra collected in the core zones of the glass fragments lack this resonance pattern and are identical to the spectra measured on the pristine (unleached) MW glass. Micro extended X-ray absorption fine structure (μ-EXAFS) and μ-XANES analyses at the Ni K-edge revealed three distinct Ni(II) species: (a) Ni uniformly distributed in the glass matrix, (b) micro-inclusions with high Ni concentrations and (c) Ni associated to the Mg-clay. The comparison with reference spectra of unleached MW and other Ni-bearing silicate glasses indicated that species (a) represents the original coordinative environment of Ni in the glass. The μ-EXAFS analyses revealed that species (b) is structural Ni in trevorite (NiFe 2O 4), which probably formed through unmixing processes during the cooling of the glass melt. The μ-EXAFS of species (c) could be successfully modeled assuming specific adsorption or incorporation of Ni into the lattice of
Peng, Song; Liu, Zhiguo; Sun, Tianxi; Wang, Guangfu; Ma, Yongzhong; Ding, Xunliang
2014-08-01
Confocal micro X-ray fluorescence (CM-XRF) with quasi-monochromatic excitation based on polycapillary X-ray optics was used to measure the thickness of multi-ply films. The relative errors of measuring an Fe film with a thickness of 16.3 μm and a Cu film with a thickness of 24.5 μm were 7.3% and 0.4%, respectively. The non-destructive and in-situ measurement of the thickness and uniformity of multi-ply films of Cu, Fe and Ni on a silicon surface was performed. CM-XRF was convenient in in-situ and elementally resolved analysis of the thickness of multi-ply films without a cumbersome theoretical correction model. Copyright © 2014 Elsevier Ltd. All rights reserved.
NASA Astrophysics Data System (ADS)
Delhez, Robert; Van der Gaast, S. J.; Wielders, Arno; de Boer, J. L.; Helmholdt, R. B.; van Mechelen, J.; Reiss, C.; Woning, L.; Schenk, H.
2003-02-01
The mineralogy of the surface material of Mars is the key to disclose its present and past life and climates. Clay mineral species, carbonates, and ice (water and CO2) are and/or contain their witnesses. X-ray powder diffraction (XRPD) is the most powerful analytical method to identify and quantitatively characterize minerals in complex mixtures. This paper discusses the development of a working model of an instrument consisting of a reflection mode diffractometer and a transmission mode CCD-XRPD instrument, combined with an XRF module. The CCD-XRD/XRF instrument is analogous to the instrument for Mars missions developed by Sarrazin et al. (1998). This part of the tandem instrument enables "quick and dirty" analysis of powdered (!) matter to monitor semi-quantitatively the presence of clay minerals as a group, carbonates, and ices and yields semi-quantitative chemical information from X-ray fluorescence (XRF). The reflection mode instrument (i) enables in-situ measurements of rocks and soils and quantitative information on the compounds identified, (ii) has a high resolution and reveals large spacings for accurate identification, in particular of clay mineral species, and (iii) the shape of the line profiles observed reveals the kind and approximate amounts of lattice imperfections present. It will be shown that the information obtained with the reflection mode diffractometer is crucial for finding signs of life and changes in the climate on Mars. Obviously this instrument can also be used for other extra-terrestrial research.
NASA Astrophysics Data System (ADS)
Bradley, D. A.; Ng, K. H.; Green, S.; Mountford, P. J.; Shukri, A.; Evans, J.
1996-05-01
Members of this group have responded to a number of challenging health issues by attempting to devise sensitive XRF, NAA and low-kV radiographic measurement systems foboth in vivo and in vitro applications. These studies are generally either of toxicological importance, examine potential for diagnosing the presence of disease, or offer effective means for monitoring potentially harmful side-effects of therapy. Particular examples include the in vivo XRF investigation of human skeletal uptake of Pb in working and living environments, in vivo XRF monitoring of elevated levels of Fe in skin (indicating the presence of an undesirable side-effect of the treatment of thalassaemia), in vivo NAA monitoring of elevated levels of Al in bone (indicating an undesirable side-effect of the treatment of chronic renal failure) and in vitro characterization, by means of low-kV imaging, of a range of calcification parameters in healthy and diseased breast tissue. The latter investigation has been conducted in association with an in vitro NAA study of concentrations of trace elements in the same types of tissue. Figures of merit for the various measurement systems have been obtained in terms of minimum detectable levels and concentrations (MDL's and MDC's) and where applicable, image related parameters.
NASA Astrophysics Data System (ADS)
Ploykrachang, K.; Hasegawa, J.; Kondo, K.; Fukuda, H.; Oguri, Y.
2014-07-01
We have developed a micro-XRF system based on a proton-induced quasimonochromatic X-ray (QMXR) microbeam for in vivo measurement of biological samples. A 2.5-MeV proton beam impinged normally on a Cu foil target that was slightly thicker than the proton range. The emitted QMXR behind the Cu target was focused with a polycapillary X-ray half lens. For application to analysis of wet or aquatic samples, we prepared a QMXR beam with an incident angle of 45° with respect to the horizontal plane by using a dipole magnet in order to bend the primary proton beam downward by 45°. The focal spot size of the QMXR microbeam on a horizontal sample surface was evaluated to be 250 × 350 μm by a wire scanning method. A microscope camera with a long working distance was installed perpendicular to the sample surface to identify the analyzed position on the sample. The fluorescent radiation from the sample was collected by a Si-PIN photodiode X-ray detector. Using the setup above, we were able to successfully measure the accumulation and distribution of Co in the leaves of a free-floating aquatic plant on a dilute Co solution surface.
Performance of a Borehole XRF Spectrometer for Planetary Exploration
NASA Technical Reports Server (NTRS)
Kelliher, Warren C.; Carlberg, Ingrid A.; Elam, W. T.; WIllard-Schmoe, Ella
2007-01-01
We have designed and constructed a borehole XRF Spectrometer (XRFS) as part of the Mars Subsurface Access program. It will be used to determine the composition of the Mars regolith at various depths by insertion into a pre-drilled borehole. The primary performance metrics for the instrument are the lower limits of detection over a wide range of the periodic table. Power consumption during data collection was also measured. The prototype instrument is complete and preliminary testing has been performed. Terrestrial soil Standard Reference Materials were used as the test samples. Detection limits were about 10 weight parts-per-million for most elements, with light elements being higher, up to 1.4 weight percent for magnesium. Power consumption (excluding ground support components) was 12 watts.
Final report: Mapping Interactions in Hybrid Systems with Active Scanning Probes
DOE Office of Scientific and Technical Information (OSTI.GOV)
Berezovsky, Jesse
2017-09-29
This project aimed to study and map interactions between components of hybrid nanodevices using a novel scanning probe approach. To enable this work, we initially constructed a flexible experimental apparatus allowing for simultaneous scanning probe and confocal optical microscopy measurements. This setup was first used for all-optical measurements of nanostructures, with the focus then shifting to hybrid devices in which single coherent electron spins are coupled to micron-scale ferromagnetic elements, which may prove useful for addressing single spins, enhanced sensing, or spin-wave-mediated coupling of spins for quantum information applications. A significant breakthrough was the realization that it is not necessarymore » to fabricate a magnetic structure on a scanning probe – instead a ferromagnetic vortex core can act as an integrated, solid state, scanning probe. The core of the vortex produces a very strong, localized fringe field which can be used analogously to an MFM tip. Unlike a traditional MFM tip, however, the vortex core is scanned within an integrated device (eliminating drift), and can be moved on vastly faster timescales. This approach allows the detailed investigation of interactions between single spins and complex driven ferromagnetic dynamics.« less
Micro CT characterization of a coastal mine tailings deposit, Portmán Bay, SE Spain
NASA Astrophysics Data System (ADS)
Frigola, Jaime; Cerdà-Domènech, Marc; Barriuso, Eduardo; Sanchez-Vidal, Anna; Amblas, David; Canals, Miquel
2017-04-01
Scanning of sediment cores by means of high-resolution non-destructive techniques provides researchers with huge amounts of highly valuable data allowing fast and detailed characterization of the materials. In the last decades several devoted instruments have been developed and applied to the study of sedimentary sequences, mainly multi-sensor core loggers (MSCL) for the physical properties and XRF core scanners for the chemical elemental composition. The geoscientific community started using computed tomography (CT) systems about two decades ago. These were mainly medical systems as dedicated instruments were essentially lacking by that time. The resolution of those medical systems was limited to several hundreds of micrometres voxel size. Micro computed tomography (micro-CT) systems have also spread into geoscientific research, although their limited workspace dimensions prevents their use for large objects, such as long sediment cores. Recently, a new micro-CT system, the MultiTom Core X-ray CT, conceived by University of Barcelona (UB) researchers and developed by X-ray Engineering, became operational. It is able of scanning sediment cores up to 1.5 m long, and allows adjustable resolutions from 300 microns down to 3-4 microns. The system is now installed at UB's CORELAB Laboratory for non-destructive analyses of geological materials. Here we present, as an example, the results of MultiTom scans of a set of sediment cores recovered offshore Portmán Bay, SE Spain, in order to characterize at very high-resolution the metal-enriched deposit generated after 33 years of direct discharge into the sea of mine tailings resulting from the exploitation of Pb and Zn ores. In total 52 short cores and 6 long gravity cores from the mine tailings infilled bay were scanned with the MultiTom system at a mean voxel resolution of 125 microns. The integrated study of micro-CT data allowed differentiating the main tailings units from deposits formed after disposal cessation
3D anatomy of Heinrich Layer 2
NASA Astrophysics Data System (ADS)
van Rooij, D.; Zaazi, N.; Fagel, N.; Boone, M.; Cnudde, V.; Dewanckele, J.; Pirlet, H.; Rohl, U.; Blamart, D.; Henriet, J.-P.; Jacobs, P.; Houbrechts, H.; Duyck, P.; Swennen, R.
2009-04-01
Heinrich Layers are found in the North Atlantic Ocean as well-constrained markers of catastrophic iceberg surges from the Pan-Atlantic ice sheets during the last glacial cycle. Their physical and geochemical characteristics allow for relatively fast diagnostics using the state-of-the-art core scanners such as a Multi-Sensor Core Logger and an XRF core scanner. The nature of these characteristics are predominantly due to the source sediments of the ice-rafted debris (IRD) on the one hand (magnetic susceptibility, color, carbonate content) and the response of the palaeo-environment on the other hand (carbonate content, foraminiferal assemblage). However, changes in (gamma) bulk density of the sediment within a Heinrich Layer cannot solely be explained due to the higher content of IRD. Sediment cores in the Porcupine Seabight (West off Ireland) have shown the presence of Heinrich Events without the diagnostic changes in magnetic susceptibility (MS), suggesting a more drastic change in oceanography which could cause widespread diagenesis on the seabed during Heinrich Events. In order to better understand the physical behavior of a Heinrich Layer, 2 cores were studied taken from the northern Porcupine Seabight by R/V Marion Dufresne campaign MD123 in September 2001. More specifically HL2 was studied since it carries the most typical HL signature. The main anatomical information, with a resolution of 0.5 mm, was obtained by means of medical computed tomography of half-core sections of 50 cm length from the Ghent University Hospital. This information was used for detailed sampling for mineralogy, grainsize measurements and palaeoenvironmental analyses. On one core section, XRF core scanning was performed at a 0.5 cm interval. Higher-resolution information was obtained from five 8 cc subsamples which underwent µCT scanning and cold-cathode luminescence microscopy. The results of this unique approach show a rather surprising 3D view of a Heinrich Layer. As expected, the
NASA Astrophysics Data System (ADS)
Debastiani, Rafaela; Simon, Rolf; Goettlicher, Joerg; Heissler, Stefan; Steininger, Ralph; Batchelor, David; Fiederle, Michael; Baumbach, Tilo
2016-10-01
Roman mural green pigment painting fragments from three Roman sites in the north of the Roman province Germania Superior: Koblenz Stadtwald Remstecken (KOSR), Weißenthurm " Am guten Mann" (WEIS) and Mendig Lungenkärchen (MELU), dating from second and third centuries AD were analyzed. The experiments were performed nondestructively using synchrotron-based scanning macro-X-ray fluorescence (SR-MA-XRF), synchrotron-based scanning micro-X-ray fluorescence (SR-μ-XRF), synchrotron-based X-ray diffraction (SR-XRD) and Raman spectroscopy. Correlation between SR-MA-XRF, SR-μ-XRF elemental map distributions and optical images of scanned areas was mainly found for the elements Ca, Fe and K. With XRF, Fe and K were identified correlated with green pigment, but in samples from two sites, Mendig Lungenkärchen and Weißenthurm " Am guten Mann", also Cu was detected in minor concentration. The results of SR-XRD and Raman spectroscopy were limited to one sample from Weißenthurm " Am guten Mann". In this sample, green earth and calcium carbonate were identified by SR-XRD and, additionally, malachite by Raman spectroscopy.
Entrapment of carbon dioxide with chitosan-based core-shell particles containing changeable cores.
Dong, Yanrui; Fu, Yinghao; Lin, Xia; Xiao, Congming
2016-08-01
Water-soluble chitosan-based core-shell particles that contained changeable cores were successfully applied to anchor carbon dioxide. The entrapment capacity of the particles for carbon dioxide (EC) depended on the cores. It was found that EC of the particles contained aqueous cores was higher than that of the beads with water-soluble chitosan gel cores, which was confirmed with thermogravimetric analysis. In addition, calcium ions and sodium hydroxide were introduced within the particles to examine their effect on the entrapment. EC of the particles was enhanced with sodium hydroxide when the cores were WSC gel. The incorporation of calcium ions was helpful for stabilizing carbon dioxide through the formation of calcium carbonate, which was verified with Fourier transform infrared spectra and scanning electron microscopy/energy-dispersive spectrometry. This phenomenon meant the role of calcium ions for fixating carbon dioxide was significant. Copyright © 2016 Elsevier B.V. All rights reserved.
Guild, Georgia E.; Stangoulis, James C. R.
2016-01-01
Within the HarvestPlus program there are many collaborators currently using X-Ray Fluorescence (XRF) spectroscopy to measure Fe and Zn in their target crops. In India, five HarvestPlus wheat collaborators have laboratories that conduct this analysis and their throughput has increased significantly. The benefits of using XRF are its ease of use, minimal sample preparation and high throughput analysis. The lack of commercially available calibration standards has led to a need for alternative calibration arrangements for many of the instruments. Consequently, the majority of instruments have either been installed with an electronic transfer of an original grain calibration set developed by a preferred lab, or a locally supplied calibration. Unfortunately, neither of these methods has been entirely successful. The electronic transfer is unable to account for small variations between the instruments, whereas the use of a locally provided calibration set is heavily reliant on the accuracy of the reference analysis method, which is particularly difficult to achieve when analyzing low levels of micronutrient. Consequently, we have developed a calibration method that uses non-matrix matched glass disks. Here we present the validation of this method and show this calibration approach can improve the reproducibility and accuracy of whole grain wheat analysis on 5 different XRF instruments across the HarvestPlus breeding program. PMID:27375644
von Bergen, Martin; Barghorn, Stefan; Müller, Shirley A; Pickhardt, Marcus; Biernat, Jacek; Mandelkow, Eva-Maria; Davies, Peter; Aebi, Ueli; Mandelkow, Eckhard
2006-05-23
In Alzheimer's disease and frontotemporal dementias the microtubule-associated protein tau forms intracellular paired helical filaments (PHFs). The filaments formed in vivo consist mainly of full-length molecules of the six different isoforms present in adult brain. The substructure of the PHF core is still elusive. Here we applied scanning transmission electron microscopy (STEM) and limited proteolysis to probe the mass distribution of PHFs and their surface exposure. Tau filaments assembled from the three repeat domain have a mass per length (MPL) of approximately 60 kDa/nm and filaments from full-length tau (htau40DeltaK280 mutant) have approximately 160 kDa/nm, compared with approximately 130 kDa/nm for PHFs from Alzheimer's brain. Polyanionic cofactors such as heparin accelerate assembly but are not incorporated into PHFs. Limited proteolysis combined with N-terminal sequencing and mass spectrometry of fragments reveals a protease-sensitive N-terminal half and semiresistant PHF core starting in the first repeat and reaching to the C-terminus of tau. Continued proteolysis leads to a fragment starting at the end of the first repeat and ending in the fourth repeat. PHFs from tau isoforms with four repeats revealed an additional cleavage site within the middle of the second repeat. Probing the PHFs with antibodies detecting epitopes either over longer stretches in the C-terminal half of tau or in the fourth repeat revealed that they grow in a polar manner. These data describe the physical parameters of the PHFs and enabled us to build a model of the molecular arrangement within the filamentous structures.
Yoshimura, Ken; Hama, Natsuki; Shindo, Junji; Kobayashi, Kan; Kageyama, Ikuo
2008-01-01
We examined the epithelial surface and connective tissue cores (CTCs) of each lingual papilla on the Paenungulata, Cape hyrax (Procavia capensis), by scanning electron microscopy and light microscopy. The tongue consisted of a lingual apex, lingual body and lingual root. Filiform, fungiform and foliate papillae were observed on the dorsal surface of the tongue; however, fungiform papillae were quite diminished on the lingual prominence. Moreover, no clearly distinguishable vallate papillae were found on the tongue. Instead of vallate papillae, numerous dome-like large fungiform papillae were arranged in a row just in front of the rather large foliate papillae. Foliate papillae were situated in the one-third postero-lateral margin of the lingual body. The epithelium of filiform papillae was covered by a keratinized layer with kerato-hyaline granules, whereas weak keratinization was observed on the interpapillary epithelium. The external surface of the filiform papillae was conical in shape. CTCs of the filiform papillae were seen as a hood-like core with a semicircular concavity in the anterior portion of each core. Large filiform papillae were distributed on the lingual prominence. The CTCs of large filiform papillae after exfoliation of their epithelium consisted of a concave primary core and were associated with several small protrusions. The surface of fungiform papillae was smooth and dome-like. After removal of the epithelium, CTCs appeared as a flower bud-like primary core and were associated with several protrusions that were arranged on the rim of the primary core. Several taste buds were found on the top of the dorsal part of the epithelium of both fungiform and large fungiform papillae. Well-developed foliate papillae were seen and numerous taste buds could be observed in the lateral wall of the epithelium in a slit-like groove. The morphological characteristics of the tongue of the Cape hyrax had similarities with other Paenungulata such as Sirenia
NASA Technical Reports Server (NTRS)
Chipera, S. J.; Bish, D. L.; Vaniman, D. T.; Sherrit, S.; Bar-Cohen, Y.; Sarrazin, P.; Blake, D. F.
2003-01-01
A miniature CHEMIN XRD/XRF (X-Ray Diffraction/X-Ray Fluourescence) instrument is currently being developed for definitive mineralogic analysis of soils and rocks on Mars. One of the technical issues that must be addressed in order to enable XRD analysis on an extraterrestrial body is how best to obtain a representative sample powder for analysis. For XRD powder diffraction analyses, it is beneficial to have a fine-grained sample to reduce preferred orientation effects and to provide a statistically significant number of crystallites to the X-ray beam. Although a 2-dimensional detector as used in the CHEMIN instrument will produce good results with poorly prepared powders, the quality of the data will improve if the sample is fine-grained and randomly oriented. An Ultrasonic/Sonic Driller/Corer (USDC) currently being developed at JPL is an effective mechanism of sampling rock to produce cores and powdered cuttings. It requires low axial load (< 5N) and thus offers significant advantages for operation from lightweight platforms and in low gravity environments. The USDC is lightweight (<0.5kg), and can be driven at low power (<5W) using duty cycling. It consists of an actuator with a piezoelectric stack, ultrasonic horn, free-mass, and drill bit. The stack is driven with a 20 kHz AC voltage at resonance. The strain generated by the piezoelectric is amplified by the horn by a factor of up to 10 times the displacement amplitude. The tip impacts the free-mass and drives it into the drill bit in a hammering action. The free-mass rebounds to interact with the horn tip leading to a cyclic rebound at frequencies in the range of 60-1000 Hz. It does not require lubricants, drilling fluid or bit sharpening and it has the potential to operate at high and low temperatures using a suitable choice of piezoelectric material. To assess whether the powder from an ultrasonic drill would be adequate for analyses by an XRD/XRF spectrometer such as CHEMIN, powders obtained from the JPL
The metamorphosis of supernova SN 2008D/XRF 080109: a link between supernovae and GRBs/hypernovae.
Mazzali, Paolo A; Valenti, Stefano; Della Valle, Massimo; Chincarini, Guido; Sauer, Daniel N; Benetti, Stefano; Pian, Elena; Piran, Tsvi; D'Elia, Valerio; Elias-Rosa, Nancy; Margutti, Raffaella; Pasotti, Francesco; Antonelli, L Angelo; Bufano, Filomena; Campana, Sergio; Cappellaro, Enrico; Covino, Stefano; D'Avanzo, Paolo; Fiore, Fabrizio; Fugazza, Dino; Gilmozzi, Roberto; Hunter, Deborah; Maguire, Kate; Maiorano, Elisabetta; Marziani, Paola; Masetti, Nicola; Mirabel, Felix; Navasardyan, Hripsime; Nomoto, Ken'ichi; Palazzi, Eliana; Pastorello, Andrea; Panagia, Nino; Pellizza, L J; Sari, Re'em; Smartt, Stephen; Tagliaferri, Gianpiero; Tanaka, Masaomi; Taubenberger, Stefan; Tominaga, Nozomu; Trundle, Carrie; Turatto, Massimo
2008-08-29
The only supernovae (SNe) to show gamma-ray bursts (GRBs) or early x-ray emission thus far are overenergetic, broad-lined type Ic SNe (hypernovae, HNe). Recently, SN 2008D has shown several unusual features: (i) weak x-ray flash (XRF), (ii) an early, narrow optical peak, (iii) disappearance of the broad lines typical of SN Ic HNe, and (iv) development of helium lines as in SNe Ib. Detailed analysis shows that SN 2008D was not a normal supernova: Its explosion energy (E approximately 6x10(51) erg) and ejected mass [ approximately 7 times the mass of the Sun (M(middle dot in circle))] are intermediate between normal SNe Ibc and HNe. We conclude that SN 2008D was originally a approximately 30 M(middle dot in circle) star. When it collapsed, a black hole formed and a weak, mildly relativistic jet was produced, which caused the XRF. SN 2008D is probably among the weakest explosions that produce relativistic jets. Inner engine activity appears to be present whenever massive stars collapse to black holes.
NASA Astrophysics Data System (ADS)
D'Andrea, W. J.; Balascio, N. L.; Bradley, R. S.; Bakke, J.; Gjerde, M.; Kaufman, D. S.; Briner, J. P.; von Gunten, L.
2014-12-01
Generating continuous, accurate and quantitative Holocene temperature estimates from the Arctic is an ongoing challenge. In many Arctic regions, tree ring-based approaches cannot be used and lake sediments provide the most valuable repositories for extracting paleotemperature information. Advances in lacustrine alkenone paleothermometry now allow for quantitative reconstruction of lake-water temperature based on the UK37 values of sedimentary alkenones. In addition, a recent study demonstrated the efficacy of non-destructive scanning reflectance spectroscopy in the visible range (VIS-RS) for high-resolution quantitative temperature reconstruction from arctic lake sediments1. In this presentation, I will report a new UK37-based temperature reconstruction and a scanning VIS-RS record (using the RABD660;670 index as a measure of sedimentary chlorin content) from Kulusuk Lake in southeastern Greenland (65.6°N, 37.1°W). The UK37 record reveals a ~3°C increase in summer lake water temperatures between ~10ka and ~7ka followed by sustained warmth until ~4ka and a gradual (~3°C) cooling until ~400 yr BP. The strong correlation between UK37 and RABD660;670 measured in the same sediment core provides further evidence that in arctic lakes where temperature regulates primary productivity, and thereby sedimentary chlorin content, these proxies can be combined to develop high-resolution quantitative temperature records. The Holocene temperature history of Kulusuk Lake determined using this approach corresponds to changes in the size of the glaciers adjacent to the lake, as inferred from sediment minerogenic properties measured with scanning XRF. Glaciers retreated during early Holocene warming, likely disappeared during the period of mid-Holocene warmth, and advanced after 4ka. I will also discuss new UK37 and RABD660;670 reconstructions from northwestern Svalbard and the central Brooks Range of Alaska within the framework of published regional temperature reconstructions and
Recent developments in spectroscopic imaging techniques for historical paintings - A review
NASA Astrophysics Data System (ADS)
Alfeld, M.; de Viguerie, L.
2017-10-01
This paper provides an overview over the application of scanning macro-XRF with mobile instruments for the investigation of historical paintings. The method is compared to synchrotron based macro-XRF imaging and Neutron Activation Auto-Radiography. Full-Field XRF imaging instruments, a potential future alternative to scanning macro-XRF, and confocal XRF, providing complementary depth profiles and developing into a 3D imaging technique itself, are described with the focus on investigations of historical paintings. Recent developments of X-ray radiography are presented and the investigation of cultural heritage objects other than paintings by MA-XRF is summarized. In parallel to XRF, hyperspectral imaging in the visible and range has developed into a technique with comparable capabilities, providing insight in chemical compounds, where XRF imaging identifies the distribution of elements. Due to the complementary nature of these techniques the latter is summarized. Further, progress and state of the art in data evaluation for spectroscopic imaging is discussed. In general it could be observed that technical capabilities in MA-XRF and hyperspectral imaging have reached a plateau and that with the availability of commercial instruments the focus of recent studies has shifted from the development of methods to applications of the instruments. Further, that while simple instruments are easily available with medium budgets only few groups have high-end instrumentation available, bought or in-house built.
Adhesion of resin composite core materials to dentin.
O'Keefe, K L; Powers, J M
2001-01-01
This study determined (1) the effect of polymerization mode of resin composite core materials and dental adhesives on the bond strength to dentin, and (2) if dental adhesives perform as well to dentin etched with phosphoric acid as to dentin etched with self-etching primer. Human third molars were sectioned 2 mm from the highest pulp horn and polished. Three core materials (Fluorocore [dual cured], Core Paste [self-cured], and Clearfil Photo Core [light cured]) and two adhesives (Prime & Bond NT Dual Cure and Clearfil SE Bond [light cured]) were bonded to dentin using two dentin etching conditions. After storage, specimens were debonded in microtension and bond strengths were calculated. Scanning electron micrographs of representative bonding interfaces were analyzed. Analysis showed differences among core materials, adhesives, and etching conditions. Among core materials, dual-cured Fluorocore had the highest bond strengths. There were incompatibilities between self-cured Core Paste and Prime & Bond NT in both etched (0 MPa) and nonetched (3.0 MPa) dentin. Among adhesives, in most cases Clearfil SE Bond had higher bond strengths than Prime & Bond NT and bond strengths were higher to self-etched than to phosphoric acid-etched dentin. Scanning electron micrographs did not show a relationship between resin tags and bond strengths. There were incompatibilities between a self-cured core material and a dual-cured adhesive. All other combinations of core materials and adhesives produced strong in vitro bond strengths both in the self-etched and phosphoric acid-etched conditions.
Nanoscopium: a Scanning Hard X-ray Nanoprobe Beamline at Synchrotron Soleil
NASA Astrophysics Data System (ADS)
Somogyi, A.; Polack, F.; Moreno, T.
2010-06-01
Nanoscopium is the single scanning hard X-ray nano-probe beamline planned at SOLEIL. This ˜155 m long beamline will fully exploit the high brilliance and coherence characteristics of the X-ray beam both for diffraction limited focusing and for contrast formation. It will offer the most advanced imaging techniques in multimodal mode and will be a research tool for a wide user community working in the fields of earth-, environmental-, and life-sciences. The different μ-μnano-probe techniques offered by the beamline will permit elemental mapping at trace (ppm) levels (scanning XRF), speciation mapping (XANES), phase gradient mapping (scanning differential phase contrast), and density-contrast based imaging of internal structures (coherent diffraction imaging) in the 30 nm to 1 μm spatial resolution range, also in "in situ conditions". Nanoscopium will cover the 5-20 keV energy range. The stability of the nanobeam will be ensured by horizontally reflecting beamline optics (a sagitally and a tangentially pre-focusing mirror, horizontally reflecting monochromators) in front of the overfilled secondary source. Trade-off between high energy resolution (ΔE/E˜10-4) and high flux (1011 ph/s with ΔE/E˜10-2) will be achieved by two interchangeable monochromators (a double crystal and a double multilayer one). KB mirror and FZP lenses will be used as focusing devices. The beamline is in the design and construction phase. It is foreseen to be open for users at the beginning of 2013.
NASA Astrophysics Data System (ADS)
Sleveland, Arve; Planke, Sverre; Zuchuat, Valentin; Franeck, Franziska; Svensen, Henrik; Midtkandal, Ivar; Hammer, Øyvind; Twitchett, Richard; Deltadalen Study Group
2017-04-01
The Siberian Traps voluminous igneous activity is considered a likely trigger for the Permian-Triassic global extinction event. However, documented evidence of the Siberian Traps environmental effects decreases away from the centre of volcanic activity in north-central Russia. Previous research on the Permian-Triassic boundary (PTB) mostly relies on field observations, and resolution has thus depended on outcrop quality. This study reports on two 90 m cored sedimentary successions intersecting the PTB in Deltadalen, Svalbard, providing high-quality material to a comprehensive documentation of the stratigraphic interval. Sequence stratigraphic concepts are utilised to help constrain the Permian-Triassic basin development models in Svalbard and the high-Arctic region. The cored sections are calibrated with outcrop data from near the drill site. One core has been systematically described and scanned using 500-μm and 200-μm resolution XRF, hyperspectral imagery and microfocus CT (latter only on selected core sections). The base of both cores represents the upper 15 m of the Permian Kapp Starostin Formation, which is dominated by green glauconitic sandstones with spiculitic cherts, and exhibit various degrees of bioturbation. The Kapp Starostin Formation is in turn sharply overlain by 2 m of heavily reworked sand- and mudstones, extensively bioturbated, representing the base of the lower Triassic Vikinghøgda Formation. These bioturbated units are conformably overlain by 9 m of ash-bearing laminated black shale where signs of biological activity both on micro- and macro-scale are limited, and is thus interpreted to have recorded the Permian-Triassic extinction interval. Descriptive sedimentology and sequence stratigraphic concepts reveal the onset of relative sea level rise at the Vikinghøgda Formation base. The disappearance of bioturbation and extensive presence of pyrite in the overlying laminated black shale of the Vikinghøgda Formation suggest near anoxic
NASA Technical Reports Server (NTRS)
Shelfer, T. D.; Morris, Richard V.; Nguyen, T.; Agresti, D. G.; Wills, E. L.
1994-01-01
We have developed a four-detector research-grade backscatter Moessbauer spectrometer (BaMS) instrument with low resolution x-ray fluorescence analysis (XRF) capability. A flight-qualified instrument based on this design would be suitable for use on missions to the surfaces of solid solar-system objects (Moon, Mars, asteroids, etc.). Target specifications for the flight instrument are as follows: mass less than 500 g; volumes less than 300 cu cm; and power less than 2 W. The BaMS/XRF instrument would provide data on the oxidation state of iron and its distribution among iron-bearing mineralogies and elemental composition information. This data is a primary concern for the characterization of extraterrestrial surface materials.
NASA Astrophysics Data System (ADS)
Sinnesael, Matthias; Loi, Alfredo; Dabard, Marie-Pierre; Vandenbroucke, Thijs; Claeys, Philippe
2017-04-01
The Middle to lower Upper Ordovician sections of the Crozon Peninsula area (Postolonnec Formation, Armorican Massif, western France) show multi-order eustatic sea-level changes (Dabard et al., 2015). The sections are characterized by siliciclastic facies, which were deposited in tidal to storm-dominated shelf environments. Dabard et al. (2015) analysed the facies, their stacking patterns, and gamma-ray data and applied backstripping to identify subsidence and several orders of sea-level change. The main stratigraphic constraints are coming from (chitinozoan) biostratigraphy. The 3th to 5th orders changes are hypothesized to correspond to various frequencies related to astronomical forcing. This study investigates the potential added value of portable X-Ray Fluorescence (pXRF) and the application of spectral analyses. High-resolution (cm-scale) non-destructive pXRF and natural gamma-ray measurements were carried out on 14 m of section that was equally logged on a cm resolution. The pXRF measurements on the surface of the outcrops are compared with earlier results of wavelength dispersive XRF spectrometry and ICP-MS. The potassium records of the pXRF and gamma-ray logs are comparable and essentially reflect lithological variations (i.e., between mudstone and coarse sandstones). Other reliably measured elements also reflected lithological aspects such as clay-sandstone alternations (e.g. K, Rb, Ti), placer locations (Zr, Ce, Ti) and potentially clay mineralogy and condensation horizons (Ni, Zn, Co, Mn). Spectral analyses of the various proxies (lithology, natural gamma-ray and pXRF) are compared with each other. Both the new high-resolution data (14 m of section) as well as the published low-resolution data (which span almost 400 m of Darriwilian-Sandbian) were analyzed. The study reveals strong indications for the imprint of obliquity, precession and eccentricity. Obtaining age constraints, in addition to the existing biostratigraphical framework is a challenge in
Long term fine aerosol analysis by XRF and PIXE techniques in the city of Rijeka, Croatia
NASA Astrophysics Data System (ADS)
Ivošević, Tatjana; Orlić, Ivica; Radović, Iva Bogdanović
2015-11-01
The results of a long term, multi elemental XRF and PIXE analysis of fine aerosol pollution in the city of Rijeka, Croatia, are reported for the first time. The samples were collected during a seven months period (6th Aug 2013-28th Feb 2014) on thin stretched Teflon filters and analyzed by energy dispersive X-ray fluorescence (EDXRF) at the Laboratory for Elemental Micro-Analysis (LEMA), University of Rijeka and by Particle Induced X-ray Emission (PIXE) using 1.6 MeV protons at the Laboratory for Ion Beam Interactions (LIBI), Ruđer Bošković Institute, Zagreb. The newly developed micro-XRF system at LEMA provided results for 19 elements in the range from Si to Pb. The PIXE at the LIBI provided information for the same elements as well for the light elements such as Na, Mg and Al. Black carbon was determined with the Laser Integrated Plate Method (LIPM). The results were statistically evaluated by means of the positive matrix factorization (PMF). The seven major pollution sources were identified together with their relative contributions, these are: secondary sulfates, road traffic, smoke, road dust, sea spray, ship emissions and soil dust.
NASA Astrophysics Data System (ADS)
Chapman, J.; Kulhanek, D. K.; Rosenthal, Y.; Holbourn, A. E.
2017-12-01
International Ocean Discovery Program (IODP) Expedition 363 sought to determine the nature of and driving forces behind climate variability in the Western Pacific Warm Pool (WPWP) region throughout the Neogene on millennial, orbital, and geologic timescales. Our research focuses on the Pliocene to recent (4-0 Ma) sediment record from IODP Site U1490 to examine changes in carbonate production and burial in the WPWP as a record of variations in the regional/global carbon cycle. This interval is of particular interest because it spans the Middle Pliocene Warm Period, the initiation of Northern Hemisphere Glaciation, and the Mid-Pleistocene Transition. Site U1490 is located on the northern edge of Eauripik Rise at 05°58.95'N, 142°39.27'E in the northern part of the WPWP. At 2341 m water depth, today the site is bathed in Upper Circumpolar Deepwater. Pliocene to recent sediment primarily consists of foraminifer-rich nannofossil ooze, with the sedimentation rate varying between 1.5 and 3 cm/kyr. Initial shipboard measurement of calcium carbonate content shows little variation at low resolution (1 sample every few meters), varying between 90 and 95 wt%. We collected X-ray fluorescence (XRF) data at 2 cm resolution along the composite stratigraphic section to obtain a qualitative measure of the bulk chemistry of the sediment. We will use the weight percent calcium carbonate of discrete samples to calibrate the XRF data to generate a high-resolution carbonate record. We observe cyclical variations in the Ca/Ba, which may reflect variations in productivity and/or dissolution through this interval, although additional work is needed to fully interpret these data. Ultimately our research will allow for comparison between records obtained from these cores located in the western equatorial Pacific to those obtained in the eastern and central Pacific, which will better elucidate the nature of the carbon system during the Plio-Pleistocene.
XRF-analysis of fine and ultrafine particles emitted from laser printing devices.
Barthel, Mathias; Pedan, Vasilisa; Hahn, Oliver; Rothhardt, Monika; Bresch, Harald; Jann, Oliver; Seeger, Stefan
2011-09-15
In this work, the elemental composition of fine and ultrafine particles emitted by ten different laser printing devices (LPD) is examined. The particle number concentration time series was measured as well as the particle size distributions. In parallel, emitted particles were size-selectively sampled with a cascade impactor and subsequently analyzed by the means of XRF. In order to identify potential sources for the aerosol's elemental composition, materials involved in the printing process such as toner, paper, and structural components of the printer were also analyzed. While the majority of particle emissions from laser printers are known to consist of recondensated semi volatile organic compounds, elemental analysis identifies Si, S, Cl, Ca, Ti, Cr, and Fe as well as traces of Ni and Zn in different size fractions of the aerosols. These elements can mainly be assigned to contributions from toner and paper. The detection of elements that are likely to be present in inorganic compounds is in good agreement with the measurement of nonvolatile particles. Quantitative measurements of solid particles at 400 °C resulted in residues of 1.6 × 10(9) and 1.5 × 10(10) particles per print job, representing fractions of 0.2% and 1.9% of the total number of emitted particles at room temperature. In combination with the XRF results it is concluded that solid inorganic particles contribute to LPD emissions in measurable quantities. Furthermore, for the first time Br was detected in significant concentrations in the aerosol emitted from two LPD. The analysis of several possible sources identified the plastic housings of the fuser units as main sources due to substantial Br concentrations related to brominated flame retardants.
Measurements of Strontium Levels in Human Bone In Vivo Using Portable X-ray Fluorescence (XRF).
Specht, Aaron J; Mostafaei, Farshad; Lin, Yanfen; Xu, Jian; Nie, Linda H
2017-08-01
Measurement of bone strontium (Sr) is vital to determining the effectiveness of Sr supplementation, which is commonly used for the treatment of osteoporosis. Previous technology uses radioisotope sources and bulky equipment to measure bone Sr. This study demonstrates the effectiveness of portable X-ray fluorescence (XRF) for bone Sr measurement and validates it using data from a population of 238 children. We identified correlations between bone Sr and age in our participants.
NASA Astrophysics Data System (ADS)
Lee, An-Sheng; Lu, Wei-Li; Huang, Jyh-Jaan; Chang, Queenie; Wei, Kuo-Yen; Lin, Chin-Jung; Liou, Sofia Ya Hsuan
2016-04-01
Through the geology and climate characteristic in Taiwan, generally rivers carry a lot of suspended particles. After these particles settled, they become sediments which are good sorbent for heavy metals in river system. Consequently, sediments can be found recording contamination footprint at low flow energy region, such as estuary. Seven sediment cores were collected along Nankan River, northern Taiwan, which is seriously contaminated by factory, household and agriculture input. Physico-chemical properties of these cores were derived from Itrax-XRF Core Scanner and grain size analysis. In order to interpret these complex data matrices, the multivariate statistical techniques (cluster analysis, factor analysis and discriminant analysis) were introduced to this study. Through the statistical determination, the result indicates four types of sediment. One of them represents contamination event which shows high concentration of Cu, Zn, Pb, Ni and Fe, and low concentration of Si and Zr. Furthermore, three possible contamination sources of this type of sediment were revealed by Factor Analysis. The combination of sediment analysis and multivariate statistical techniques used provides new insights into the contamination depositional history of Nankan River and could be similarly applied to other river systems to determine the scale of anthropogenic contamination.
NASA Astrophysics Data System (ADS)
Bleacher, J. E.; Gendreau, K.; Arzoumanian, Z.; Young, K. E.; McAdam, A.
2018-02-01
Science instruments to be used during human exploration should be designed to serve as multipurpose tools that are of use throughout a mission. Here we discuss a multipurpose tool approach to using contact XRD/XRF onboard the Deep Space Gateway.
NASA Astrophysics Data System (ADS)
Bártová, H.; Trojek, T.; Čechák, T.; Šefců, R.; Chlumská, Š.
2017-10-01
The presence of heavy chemical elements in old pigments is possible to identify in historical paintings using X-ray fluorescence analysis (XRF). This is a non-destructive analytical method frequently used in examination of objects that require in situ analysis, where it is necessary to avoid damaging the object by taking samples. Different modalities are available, such as microanalysis, scanning selected areas, or depth profiling techniques. Surface scanning is particularly profitable since 2D element distribution maps are much more understandable than the results of individual analyses. Information on the layered structure of the painting can be also obtained by handheld portable systems. Results presented in our paper combine 2D element distribution maps obtained by scanning analysis, and depth profiling using conventional XRF. The latter is very suitable for objects of art, as it can be evaluated from data measured with portable XRF device. Depth profiling by conventional XRF is based on the differences in X-ray absorption in paint layers. The XRF technique was applied for analysis of panel paintings of the Master of the St George Altarpiece who was active in Prague in the 1470s and 1480s. The results were evaluated by taking micro-samples and performing a material analysis.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kunimura, Shinsuke; Hatakeyama, So; Sasaki, Nobuharu
A portable total reflection X-ray fluorescence (TXRF) spectrometer that we have developed is applied to trace elemental analysis of water solutions. Although a 5 W X-ray tube is used in the portable TXRF spectrometer, detection limits of several ppb are achieved for 3d transition metal elements and trace elements in a leaching solution of soils, a leaching solution of solder, and alcoholic beverages are detected. Portable X-ray fluorescence (XRF) spectromicroscopes with a 1 W X-ray tube and an 8 W X-ray tube are also presented. Using the portable XRF spectromicroscope with the 1 W X-ray tube, 93 ppm of Crmore » is detected with an about 700 {mu}m spatial resolution. Spatially resolved elemental analysis of a mug painted with blue, red, green, and white is performed using the two portable spectromicroscopes, and the difference in elemental composition at each paint is detected.« less
NASA Astrophysics Data System (ADS)
Rahmani, A.; Benyaïch, F.; Bounakhla, M.; Bilal, E.; Moutte, J.; Gruffat, J. J.; Zahry, F.
2004-11-01
Dans ce travail, nous présentons une étude comparative des techniques d'analyse par fluorescence X à dispersion d'énergie (ED-XRF) et à dispersion de longueur d'onde (WD-XRF), et par spectrométrie d'émission atomique à source plasma couplée par induction (ICP-AES). Les résultats de la calibration des spectromètres à dispersion d'énergie, à excitation par sources radioactives (55Fe, 109Cd et 241Am) et à excitation secondaire (cible secondaire Mo et Cu) du Centre National pour l'Energie, les Sciences et les Techniques Nucléaires (CNESTEN, Rabat, Maroc) sur des échantillons étalons de références de l'Agence International de l'Energie Atomique (AIEA) et du Community Bureau of Référence (BCR) ont été comparés aux résultats d'analyse des mêmes échantillons étalons par la spectrométrie X à dispersion de longueur d'onde (WD-XRF) et par spectrométrie d'émission atomique à source plasma couplé par induction (ICP-AES) au département GENERIC du centre SPIN à l'Ecole des Mines de Saint-Etienne (France). Les trois techniques d'analyse utilisées donnent des résultats comparables pour le dosage des éléments majeurs, alors que pour les traces on note des déviations importantes à cause des effets de matrice qui sont difficiles à corriger dans le cas de la fluorescence X.
NASA Astrophysics Data System (ADS)
Gaillot, P.
2007-12-01
X-ray computed tomography (CT) of rock core provides nondestructive cross-sectional or three-dimensional core representations from the attenuation of electromagnetic radiation. Attenuation depends on the density and the atomic constituents of the rock material that is scanned. Since it has the potential to non-invasively measure phase distribution and species concentration, X-ray CT offers significant advantages to characterize both heterogeneous and apparently homogeneous lithologies. In particular, once empirically calibrated into 3D density images, this scanning technique is useful in the observation of density variation. In this paper, I present a procedure from which information contained in the 3D images can be quantitatively extracted and turned into very-high resolution core logs and core image logs including (1) the radial and angular distributions of density values, (2) the histogram of distribution of the density and its related statistical parameters (average, 10- 25- 50, 75 and 90 percentiles, and width at half maximum), and (3) the volume, the average density and the mass contribution of three core fractions defined by two user-defined density thresholds (voids and vugs < 1.01 g/cc ≤ damaged core material < 1.25 g/cc < non-damaged core material). In turn, these quantitative outputs (1) allow the recognition of bedding and sedimentary features, as well as natural and coring-induced fractures, (2) provide a high-resolution bulk density core log, and (3) provide quantitative estimates of core voids and core damaged zones that can further be used to characterize core quality and core disturbance, and apply, where appropriate, volume correction on core physical properties (gamma-ray attenuation density, magnetic susceptibility, natural gamma radiation, non-contact electrical resistivity, P-wave velocity) acquired via Multi- Sensors Core loggers (MSCL). The procedure is illustrated on core data (XR-CT images, continuous MSCL physical properties and
DOE Office of Scientific and Technical Information (OSTI.GOV)
Manohar, N; Diagaradjane, P; Krishnan, S
2016-06-15
Purpose: To demonstrate the ability to perform high-resolution imaging and quantification of sparse distributions of gold nanoparticles (GNPs) within ex vivo tumor samples using a highly-sensitive benchtop L-shell x-ray fluorescence (XRF) imaging system. Methods: An optimized L-shell XRF imaging system was assembled using a tungsten-target x-ray source (operated at 62 kVp and 45 mA). The x-rays were filtered (copper: 0.08 mm & aluminum: 0.04 mm) and collimated (lead: 5 cm thickness, 3 cm aperture diameter) into a cone-beam in order to irradiate small samples or objects. A collimated (stainless steel: 4 cm thickness, 2 mm aperture diameter) silicon drift detector,more » capable of 2D translation, was placed at 90° with respect to the beam to acquire XRF/scatter spectra from regions of interest. Spectral processing involved extracting XRF signal from background, followed by attenuation correction using a Compton scatter-based normalization algorithm. Calibration phantoms with water/GNPs (0 and 0.00001–10 mg/cm{sup 3}) were used to determine the detection limit of the system at a 10-second acquisition time. The system was then used to map the distribution of GNPs within a 12×11×2 mm{sup 3} slice excised from the center of a GNP-loaded ex vivo murine tumor sample; a total of 110 voxels (2.65×10{sup −3} cm{sup 3}) were imaged with 1.3-mm spatial resolution. Results: The detection limit of the current cone-beam benchtop L-shell XRF system was 0.003 mg/cm{sup 3} (3 ppm). Intratumoral GNP concentrations ranging from 0.003 mg/cm{sup 3} (3 ppm) to a maximum of 0.055 mg/cm{sup 3} (55 ppm) and average of 0.0093 mg/cm{sup 3} (9.3 ppm) were imaged successfully within the ex vivo tumor slice. Conclusion: The developed cone-beam benchtop L-shell XRF imaging system can immediately be used for imaging of ex vivo tumor samples containing low concentrations of GNPs. With minor finetuning/optimization, the system can be directly adapted for performing routine preclinical in
Harper, Martin; Pacolay, Bruce; Hintz, Patrick; Bartley, David L; Slaven, James E; Andrew, Michael E
2007-11-01
This paper concludes a five-year program on research into the use of a portable X-ray fluorescence (XRF) analyzer for analyzing lead in air sampling filters from different industrial environments, including mining, manufacturing and recycling. The results from four of these environments have already been reported. The results from two additional metal processes are presented here. At both of these sites, lead was a minor component of the total airborne metals and interferences from other elements were minimal. Nevertheless, only results from the three sites where lead was the most abundant metal were used in the overall calculation of method accuracy. The XRF analyzer was used to interrogate the filters, which were then subjected to acid digestion and analysis by inductively-coupled plasma optical-emission spectroscopy (ICP-OES). The filter samples were collected using different filter-holders or "samplers" where the size (diameter), depth and homogeneity of aerosol deposit varied from sampler to sampler. The aerosol collection efficiencies of the samplers were expected to differ, especially for larger particles. The distribution of particles once having entered the sampler was also expected to differ between samplers. Samplers were paired to allow the between-sampler variability to be addressed, and, in some cases, internal sampler wall deposits were evaluated and compared to the filter catch. It was found, rather surprisingly, that analysis of the filter deposits (by ICP-OES) of all the samplers gave equivalent results. It was also found that deposits on some of the sampler walls, which in some protocols are considered part of the sample, could be significant in comparison to the filter deposit. If it is concluded that wall-deposits should be analyzed, then XRF analysis of the filter can only give a minimum estimate of the concentration. Techniques for the statistical analysis of field data were also developed as part of this program and have been reported
Naturally occurring levels of elements in fishes as determined by PIXE and XRF methods
NASA Astrophysics Data System (ADS)
Tallandini, L.; Giacobini, F.; Turchetto, M.; Galassini, S.; Liu, Q. X.; Shao, H. R.; Moschini, G.; Moro, R.; Gialanella, G.; Ghermandi, G.; Cecchi, R.; Injuk, J.; Valković, V.
1989-04-01
Naturally occurring levels of S, Cl, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Sb, Sr and Pb were measured in the gills, liver and muscles of fishes ( Zosterisessor ophiocephalus Pall) in the northwestern region of the Adriatic Sea. The overall performance of PIXE and XRF methods was tested by the analysis of standard reference materials. The mean concentration values for elements were calculated from the distribution of experimentally determined concentration values. The obtained data are discussed in the framework of metal metabolism and toxicology.
Clark, Robin J. H.; Jones, Richard; Gibbs, Robert
2016-01-01
Non-destructive pigment analysis by Raman microscopy (RM) and portable X-ray fluorescence (pXRF) has been carried out on some Bolognese illuminations and cuttings chosen to represent the beginnings, evolution and height of Bolognese illuminated manuscript production. Dating to the thirteenth and fourteenth centuries and held in a private collection, the study provides evidence for the pigments generally used in this period. The results, which are compared with those obtained for other north Italian artwork, show the developments in usage of artistic materials and technique. Also addressed in this study is an examination of the respective roles of RM and pXRF analysis in this area of technical art history. This article is part of the themed issue ‘Raman spectroscopy in art and archaeology’. PMID:27799427
NASA Astrophysics Data System (ADS)
Ross, P.-S.; Bourke, A.
2017-01-01
Physical property measurements are increasingly important in mining exploration. For density determinations on rocks, one method applicable on exploration drill cores relies on gamma ray attenuation. This non-destructive method is ideal because each measurement takes only 10 s, making it suitable for high-resolution logging. However calibration has been problematic. In this paper we present new empirical, site-specific correction equations for whole NQ and BQ cores. The corrections force back the gamma densities to the "true" values established by the immersion method. For the NQ core caliber, the density range extends to high values (massive pyrite, 5 g/cm3) and the correction is thought to be very robust. We also present additional empirical correction factors for cut cores which take into account the missing material. These "cut core correction factors", which are not site-specific, were established by making gamma density measurements on truncated aluminum cylinders of various residual thicknesses. Finally we show two examples of application for the Abitibi Greenstone Belt in Canada. The gamma ray attenuation measurement system is part of a multi-sensor core logger which also determines magnetic susceptibility, geochemistry and mineralogy on rock cores, and performs line-scan imaging.
X-ray CT core imaging of Oman Drilling Project on D/V CHIKYU
NASA Astrophysics Data System (ADS)
Michibayashi, K.; Okazaki, K.; Leong, J. A. M.; Kelemen, P. B.; Johnson, K. T. M.; Greenberger, R. N.; Manning, C. E.; Harris, M.; de Obeso, J. C.; Abe, N.; Hatakeyama, K.; Ildefonse, B.; Takazawa, E.; Teagle, D. A. H.; Coggon, J. A.
2017-12-01
We obtained X-ray computed tomography (X-ray CT) images for all cores (GT1A, GT2A, GT3A and BT1A) in Oman Drilling Project Phase 1 (OmanDP cores), since X-ray CT scanning is a routine measurement of the IODP measurement plan onboard Chikyu, which enables the non-destructive observation of the internal structure of core samples. X-ray CT images provide information about chemical compositions and densities of the cores and is useful for assessing sample locations and the quality of the whole-round samples. The X-ray CT scanner (Discovery CT 750HD, GE Medical Systems) on Chikyu scans and reconstructs the image of a 1.4 m section in 10 minutes and produces a series of scan images, each 0.625 mm thick. The X-ray tube (as an X-ray source) and the X-ray detector are installed inside of the gantry at an opposing position to each other. The core sample is scanned in the gantry with the scanning rate of 20 mm/sec. The distribution of attenuation values mapped to an individual slice comprises the raw data that are used for subsequent image processing. Successive two-dimensional (2-D) slices of 512 x 512 pixels yield a representation of attenuation values in three-dimensional (3-D) voxels of 512 x 512 by 1600 in length. Data generated for each core consist of core-axis-normal planes (XY planes) of X-ray attenuation values with dimensions of 512 × 512 pixels in 9 cm × 9 cm cross-section, meaning at the dimensions of a core section, the resolution is 0.176 mm/pixel. X-ray intensity varies as a function of X-ray path length and the linear attenuation coefficient (LAC) of the target material is a function of the chemical composition and density of the target material. The basic measure of attenuation, or radiodensity, is the CT number given in Hounsfield units (HU). CT numbers of air and water are -1000 and 0, respectively. Our preliminary results show that CT numbers of OmanDP cores are well correlated to gamma ray attenuation density (GRA density) as a function of chemical
The ICDP Dead Sea deep drill cores: records of climate change and tectonics in the Levant
NASA Astrophysics Data System (ADS)
Goldstein, S. L.; Stein, M.; Ben-Avraham, Z.; Agnon, A.; Ariztegui, D.; Brauer, A.; Haug, G. H.; Ito, E.; Kitagawa, H.; Torfstein, A.
2012-12-01
The Dead Sea drainage basin sits at the boundary of the Mediterranean and the Saharan climate zones, and the basin is formed by the Dead Sea transform fault. The ICDP-funded Dead Sea Deep Drilling Project recovered the longest and most complete paleo-environmental and paleo-seismic record in the Middle East, drilling holes of ~450 and ~350 meters in deep (~300 m below the lake level) and shallow sites (~3 m), respectively, and. The sediments record the evolving environmental conditions (e.g. droughts, rains, floods, dust-storms), as well as tectonics (earthquake layers). The core can be dated using 14C on organic materials, U-Th on inorganic aragonite, stable isotopes, and layer counting. They were opened, described, and XRF-scanned during June to November 2011, the first sampling party took place in July 2012, and study is now underway. Some important conclusions can already be drawn. The stratigraphy reflects the climate conditions. During wet climate intervals the lithology is typically varve-like laminated aragonite and detritus (aad), reflecting summer and winter seasons, respectively, and sequences of mud. Gypsum layers reflect more arid climate, and salt (halite) indicates extreme aridity. The Dead Sea expands during glacials, and the portion of the core that corresponds to the last glacial Lisan Formation above the shoreline is easily recognized in the core based on the common lithological sequence, and this allows us to infer a broad scale age model. Interglacials show all the lithologic facies (aad, mud, gypsum, salt), reflecting extreme climate variability, while glacials contain the aad, mud, and gypsum but lack salt layers. Thus we estimate that the deep site hole extends into MIS 7 (to ~200,000 years). Thin (up to several cm thick) seismic layers occur throughout the core, but thick (up to several meters) landslide deposits only occur during glacial intervals. The most dramatic discovery is evidence of an extreme dry interval during MIS 5 at the deep
NASA Astrophysics Data System (ADS)
Uffelman, Erich S.; Hobbs, Patricia A.; Barisas, Derek A. G.; Mass, Jennifer L.
2013-04-01
Portable X-ray Fluorescence Spectrometry (pXRF) was used to survey 33 works in Washington and Lee University's collection of Louise Herreshoff's paintings. This work was done both to support a condition assessment of the paintings and their pigments and to determine which paintings might be appropriate for further study in the context of ongoing key synchrotron research into the degradation mechanisms of cadmium sulfide yellow pigment (CdS).
XPS-XRF hybrid metrology enabling FDSOI process
NASA Astrophysics Data System (ADS)
Hossain, Mainul; Subramanian, Ganesh; Triyoso, Dina; Wahl, Jeremy; Mcardle, Timothy; Vaid, Alok; Bello, A. F.; Lee, Wei Ti; Klare, Mark; Kwan, Michael; Pois, Heath; Wang, Ying; Larson, Tom
2016-03-01
Planar fully-depleted silicon-on-insulator (FDSOI) technology potentially offers comparable transistor performance as FinFETs. pFET FDOSI devices are based on a silicon germanium (cSiGe) layer on top of a buried oxide (BOX). Ndoped interfacial layer (IL), high-k (HfO2) layer and the metal gate stacks are then successively built on top of the SiGe layer. In-line metrology is critical in precisely monitoring the thickness and composition of the gate stack and associated underlying layers in order to achieve desired process control. However, any single in-line metrology technique is insufficient to obtain the thickness of IL, high-k, cSiGe layers in addition to Ge% and N-dose in one single measurement. A hybrid approach is therefore needed that combines the capabilities of more than one measurement technique to extract multiple parameters in a given film stack. This paper will discuss the approaches, challenges, and results associated with the first-in-industry implementation of XPS-XRF hybrid metrology for simultaneous detection of high-k thickness, IL thickness, N-dose, cSiGe thickness and %Ge, all in one signal measurement on a FDSOI substrate in a manufacturing fab. Strong correlation to electrical data for one or more of these measured parameters will also be presented, establishing the reliability of this technique.
Micro-PIXE and micro-SR-XRF studies for Romanian archaeological gold identification
NASA Astrophysics Data System (ADS)
Constantinescu, B.
2009-04-01
For gold, trace elements are more significant for provenancing archaeological artifacts than the main components: Platinum Group Elements (PGE), Sn, Te, Sb, Hg, Pb, but also high melting point elements, such as Ta and Nb. Several small fragments of native Carpathian gold were studied using micro-PIXE technique at the AGLAE accelerator, Louvre Museum and at the Legnaro AN2000 microbeam facility, and using SR-XRF at BESSY synchrotron. The goal of the study was to identify the trace elements, especially Sn, Sb and Te. At BESSY, the SR-XRF measurements were performed in air by using a 34 keV beam to excite the characteristic X-lines in Sn-Sb-Te region. We found Sn to be present in placers from Valea Arieşului and Valea Pianului, Sb in primary gold from Zlatna, Ruda-Brad, Valea Morii, Runculeţ-Straja and Pb in primary gold from Brǎdişor-Brad, Zlatna, Runculeţ-Straja, Valea Morii, Muşariu-Brad. Ten native gold nuggets and several fragments of objects coming from Visigothic Pietroasa "The Golden Brood Hen with Its Chickens" hoard were analyzed using micro-PIXE technique at the AGLAE accelerator, Louvre Museum, Paris and at the Legnaro AN2000 microbeam facility. We found Te in primary gold from Brǎdişor-Brad, Muşariu-Brad (different samples from BESSY analyzed ones), and Roşia Montanǎ, Sb in primary gold at Bucium-Izbiţa. For Pietroasa hoard, we found Sn in the Oenochoe cup and small fibula, indicating that alluvial gold - probably from Anatolia (Pactolus river) - was used. We also detected Ta inclusions in the large fibula, indicating that Ural Mountains (the only region where Ta and Au minerals are together) gold was (at least partially) used. A spectacular application to nine Dacian gold bracelets (belonging to National History Museum of Romania) authentication is presented. These bracelets look like spirals and are based on the same artistic idea, are centred around the same theme. The number of spiral varies from 6 to 8. When uncoiled, some bracelets
CHARACTERIZATION OF CHROMIUM-CONTAMINATED SOILS USING FIELD-PORTABLE X-RAY FLUORESCENCE
A detailed characterization of the underlying and adjacent soils near a chrome plating shop utilized field-portable X- ray fluorescence (XRF) as a screening tool. XRF permitted real-time acquisition of estimates for total metal content of soils. A trailer-mounted soil coring unit...
NASA Astrophysics Data System (ADS)
Nganvongpanit, Korakot; Buddhachat, Kittisak; Piboon, Promporn; Euppayo, Thippaporn; Kaewmong, Patcharaporn; Cherdsukjai, Phaothep; Kittiwatanawong, Kongkiat; Thitaram, Chatchote
2017-04-01
The elemental composition was investigated and applied for identifying the sex and habitat of dugongs, in addition to distinguishing dugong tusks and teeth from other animal wildlife materials such as Asian elephant (Elephas maximus) tusks and tiger (Panthera tigris tigris) canine teeth. A total of 43 dugong tusks, 60 dugong teeth, 40 dolphin teeth, 1 whale tooth, 40 Asian elephant tusks and 20 tiger canine teeth were included in the study. Elemental analyses were conducted using a handheld X-ray fluorescence analyzer (HH-XRF). There was no significant difference in the elemental composition of male and female dugong tusks, whereas the overall accuracy for identifying habitat (the Andaman Sea and the Gulf of Thailand) was high (88.1%). Dolphin teeth were able to be correctly predicted 100% of the time. Furthermore, we demonstrated a discrepancy in elemental composition among dugong tusks, Asian elephant tusks and tiger canine teeth, and provided a high correct prediction rate among these species of 98.2%. Here, we demonstrate the feasible use of HH-XRF for preliminary species classification and habitat determination prior to using more advanced techniques such as molecular biology.
100-OL-1 Operable Unit Pilot Study: XRF Evaluation of Select Pre-Hanford Orchards
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bunn, Amoret L.; Fritz, Brad G.; Pulsipher, Brent A.
Prior to the acquisition of land by the U.S. Department of War in February 1943 and the creation of the Hanford Site, the land along the Columbia River was home to over 1000 people. Farming and orchard operations by both homesteaders and commercial organizations were prevalent. Orchard activities and the associated application of lead arsenate pesticide ceased in 1943, when residents were moved from the Hanford Site at the beginning of the Manhattan Project. Today, the residues from historical application of lead arsenate pesticide persist in some locations on the Hanford Site. In 2012, the U.S. Department of Energy, U.S.more » Environmental Protection Agency, and Washington State Department of Ecology established the 100-OL-1 Operable Unit (OU) through the Hanford Federal Facility Agreement and Consent Order, known as the Tri-Party Agreement. The pre-Hanford orchard lands identified as the 100-OL-1 OU are located south of the Columbia River and east of the present-day Vernita Bridge, and extend southeast to the former Hanford townsite. The discontinuous orchard lands within 100-OL-1 OU are approximately 20 km2 (5000 ac). A pilot study was conducted to support the approval of the remedial investigation/feasibility study work plan to evaluate the 100-OL-1 OU. This pilot study evaluated the use of a field portable X-ray fluorescence (XRF) analyzer for evaluating lead and arsenic concentrations on the soil surface as an indicator of lead arsenate pesticide residues in the OU. The objectives of the pilot study included evaluating a field portable XRF analyzer as the analytical method for decision making, estimating the nature and extent of lead and arsenic in surface soils in four decision units, evaluating the results for the purpose of optimizing the sampling approach implemented in the remedial investigation, and collecting information to improve the cost estimate and planning the cultural resources review for sampling activities in the remedial investigation
Jagust, William J.; Landau, Susan M.; Koeppe, Robert A.; Reiman, Eric M.; Chen, Kewei; Mathis, Chester A.; Price, Julie C.; Foster, Norman L.; Wang, Angela Y.
2015-01-01
INTRODUCTION This paper reviews the work done in the ADNI PET core over the past 5 years, largely concerning techniques, methods, and results related to amyloid imaging in ADNI. METHODS The PET Core has utilized [18F]florbetapir routinely on ADNI participants, with over 1600 scans available for download. Four different laboratories are involved in data analysis, and have examined factors such as longitudinal florbetapir analysis, use of FDG-PET in clinical trials, and relationships between different biomarkers and cognition. RESULTS Converging evidence from the PET Core has indicated that cross-sectional and longitudinal florbetapir analyses require different reference regions. Studies have also examined the relationship between florbetapir data obtained immediately after injection, which reflects perfusion, and FDG-PET results. Finally, standardization has included the translation of florbetapir PET data to a centiloid scale. CONCLUSION The PET Core has demonstrated a variety of methods for standardization of biomarkers such as florbetapir PET in a multicenter setting. PMID:26194311
Sharma, Aseem; Chatterjee, Arindam; Goyal, Manu; Parsons, Matthew S; Bartel, Seth
2015-04-01
Targeting redundancy within MRI can improve its cost-effective utilization. We sought to quantify potential redundancy in our brain MRI protocols. In this retrospective review, we aggregated 207 consecutive adults who underwent brain MRI and reviewed their medical records to document clinical indication, core diagnostic information provided by MRI, and its clinical impact. Contributory imaging abnormalities constituted positive core diagnostic information whereas absence of imaging abnormalities constituted negative core diagnostic information. The senior author selected core sequences deemed sufficient for extraction of core diagnostic information. For validating core sequences selection, four readers assessed the relative ease of extracting core diagnostic information from the core sequences. Potential redundancy was calculated by comparing the average number of core sequences to the average number of sequences obtained. Scanning had been performed using 9.4±2.8 sequences over 37.3±12.3 minutes. Core diagnostic information was deemed extractable from 2.1±1.1 core sequences, with an assumed scanning time of 8.6±4.8 minutes, reflecting a potential redundancy of 74.5%±19.1%. Potential redundancy was least in scans obtained for treatment planning (14.9%±25.7%) and highest in scans obtained for follow-up of benign diseases (81.4%±12.6%). In 97.4% of cases, all four readers considered core diagnostic information to be either easily extractable from core sequences or the ease to be equivalent to that from the entire study. With only one MRI lacking clinical impact (0.48%), overutilization did not seem to contribute to potential redundancy. High potential redundancy that can be targeted for more efficient scanner utilization exists in brain MRI protocols.
El-Taher, A
2012-01-01
The instrumental neutron activation analysis technique (INAA) was used for qualitative and quantitative analysis of granite samples collected from four locations in the Aswan area in South Egypt. The samples were prepared together with their standards and simultaneously irradiated in a neutron flux of 7×10(11)n/cm(2)s in the TRIGA Mainz research reactor. Gamma-ray spectra from an hyper-pure germanium detector were analyzed. The present study provides the basic data of elemental concentrations of granite rocks. The following elements have been determined Na, Mg, K, Fe, Mn, Sc, Cr, Ti, Co, Zn, Ga, Rb, Zr, Nb, Sn, Ba, Cs, La, Ce, Nd, Sm, Eu, Yb, Lu, Hf, Ta, Th and U. The X-ray fluorescence (XRF) was used for comparison and to detect elements, which can be detected only by XRF such as F, S, Cl, Co, Cu, Mo, Ni, Pb, Se and V. The data presented here are our contribution to understanding the elemental composition of the granite rocks. Because there are no existing databases for the elemental analysis of granite, our results are a start to establishing a database for the Egyptian granite. It is hoped that the data presented here will be useful to those dealing with geochemistry, granite chemistry and related fields. Copyright © 2011 Elsevier Ltd. All rights reserved.
NASA Astrophysics Data System (ADS)
Brady, K.; Bernard, M.; Bender, S.; Roy, Z.; Boush, L. E.; Myrbo, A.; Brown, E. T.; Buynevich, I. V.; Berman, M.; Gnivecki, P.
2013-12-01
Physical, chemical and biological properties of Duck Pond Blue Hole (DPBH), located on the southern portion of Eleuthera Island, Bahamas, were examined to analyze its depositional history and the record of climate and anthropogenic changes on the island. DPBH is a small (.001 km2), circular inland blue hole with average salinity ranging from 20-28 ppt and a maximum depth of ~8 m. Sediment cores were recovered using standard piston coring techniques along a transect consisting of three sites yielding cores of varying lengths--170, 155 and 151 cm, respectively. Radiocarbon dating, x-ray fluorescence (XRF), grain size analysis, loss on ignition (LOI), smear slide and mollusk processing and identification were performed on the cores. The sediment recovered is dominated by brown, tan and white carbonate sand with varying amounts of organic matter. Sedimentation rates vary between 0.1-0.5 mm/year. Mollusks are found throughout the cores but gastropods dominate in the upper portions, which date from 2000 years BP to present day. Bivalves are abundant in intervals dating between 5000 and 2500 years BP. The most common bivalve species were Polymesoda maritima, Anomalocardis auberiana and Ervilia concentrica. The most common gastropods were Cerithidea costata and Cerithium lutosum. Drill holes made by predaceous gastropods occur on some of the gastropods, but on most of the bivalves. Drilling frequency is highest between 5000 and 2500 years BP even though gastropods are rarely preserved in that interval. Through smear slide analysis, diatoms, forams and ostracodes were also found to occur throughout the core record. Peaks in Fe and Sr from XRF scans at 0.5 cm intervals may represent records of high atmospheric dust concentrations and sea level fluctuations, respectively. Plotting mollusk bed depths versus calibrated age reveals a sea level rise over the last 6000 years that includes a rapid rise and subsequent fall at ~2500 year BP.
Gold Provenance Studies for Romanian Archaeological Objects Using Micro-SR-XRF
NASA Astrophysics Data System (ADS)
Vasilescu, Angela; Constantinescu, Bogdan; Bugoi, Roxana; Radtke, Martin; Reinholz, Uwe; Simon, Rolf
2010-04-01
Studies by Synchrotron Radiation—X-Ray Fluorescence (SR-XRF) for the search of the presence of trace elements like Sb, Sn, Te and Pb in archaeological metallic objects found on the territory of Romania—old coins and Bronze Age jewelry, aimed to determine the provenance of the gold used in their manufacture. The results are compared with the detailed elemental composition of alluvial or primary gold samples, obtained by the same technique. This work attempted to establish the origin of the gold used for the mint of two different types of koson coins. We found that the kosons with monogram are made of refined gold, while the one used for the kosons without monogram is mainly alluvial. The gold used in the manufacture of the Calarasi Vulchitrun-type disk and the Tauteu hair ring is also of alluvial origin.
NASA Technical Reports Server (NTRS)
Sakamoti, T.; Barbier, L.; Barthelmy, S. D.; Cummings, J. R.; Fenimore, E. E.; Gehrels, N.; Hullinger, D.; Krimm, H. A.; Markwardt, C. B.
2006-01-01
We report Swift Burst Alert Telescope (BAT) observations of the X-ray flash (XRF) XRF 050416A. The fluence ratio between the 15-25 and 25-50 keV energy bands of this event is 1.5, thus making it the softest gamma-ray burst (GRB) observed by BAT so far. The spectrum is well fitted by a Band function with E(sup obs)(sub peak) of 15.0(sup +2.3)(sub -2.7) keV. Assuming the redshift of the host galaxy (z = 0.6535), the isotropic equivalent radiated energy E(sub iso) and the peak energy at the GRB rest frame (E(sup src)(sub peak)) of XRF 050416A are not only consistent with the correlation found by Amati et al. and extended to XRFs by Sakamoto et al. but also fill in the gap of this relation around the 30-80 keV range of E(sup src)(sub peak). This result tightens the validity of the E(sup src)(sub Peak)-E(sup src)(sub peak) relation from XRFs to GRBs. We also find that the jet break time estimated using the empirical relation between E(sup src)(sub peak) and the collimation corrected energy E(sub gamma), is inconsistent with the afterglow observation by the Swift X-Ray Telescope. This could be due to the extra external shock emission overlaid around the jet break time or to the nonexistence of a jet break feature for XRFs, which might be a further challenge for GRB jet emission models and XRF/GRB unification scenarios.
The Beatles, the Nobel Prize, and CT scanning of the chest.
Goodman, Lawrence R
2010-01-01
From its first test scan on a mouse, in 1967, to current medical practice, the CT scanner has become a core imaging tool in thoracic diagnosis. Initially financed by money from Beatles' record sales, the first patient scan was performed in 1971. Only 8 years later, a Nobel Prize in Physics and Medicine was awarded to Hounsfield and Cormack for their discovery. This article traces the history of CT scanner development and how each technical advance expanded chest diagnostic frontiers. Chest imaging now accounts for 30% of all CT scanning.
Controlled core removal from a D-shaped optical fiber.
Markos, Douglas J; Ipson, Benjamin L; Smith, Kevin H; Schultz, Stephen M; Selfridge, Richard H; Monte, Thomas D; Dyott, Richard B; Miller, Gregory
2003-12-20
The partial removal of a section of the core from a continuous D-shaped optical fiber is presented. In the core removal process, selective chemical etching is used with hydrofluoric (HF) acid. A 25% HF acid solution removes the cladding material above the core, and a 5% HF acid solution removes the core. A red laser with a wavelength of 670 nm is transmitted through the optical fiber during the etching. The power transmitted through the optical fiber is correlated to the etch depth by scanning electron microscope imaging. The developed process provides a repeatable method to produce an optical fiber with a specific etch depth.
NASA Astrophysics Data System (ADS)
Lauwers, D.; Candeias, A.; Coccato, A.; Mirao, J.; Moens, L.; Vandenabeele, P.
2016-03-01
In archaeometry, the advantages of a combined use of Raman spectroscopy and X-ray fluorescence spectroscopy are extensively discussed for applications such as the analysis of paintings, manuscripts, pottery, etc. Here, we demonstrate for the first time the advantage of using both techniques for analysing glyptics. These engraved gemstones or glass materials were originally used as stamps, to identify the owner, for instance on letters, but also on wine vessels. For this research, a set of 64 glyptics (42 Roman glass specimens and 22 modern ones), belonging to the collection of the museum 'Quinta das Cruzes' in Funchal (Madeira, Portugal), was analysed with portable Raman spectroscopy and handheld X-ray fluorescence (hXRF). These techniques were also used to confirm the gemological identification of these precious objects and can give extra information about the glass composition. Raman spectroscopy identifies the molecular composition as well as on the crystalline phases present. On the other hand, hXRF results show that the antique Roman glass samples are characterised with low Pb and Sn levels and that the modern specimens can be discriminated in two groups: lead-based and non-lead-based ones.
Lauwers, D; Candeias, A; Coccato, A; Mirao, J; Moens, L; Vandenabeele, P
2016-03-15
In archaeometry, the advantages of a combined use of Raman spectroscopy and X-ray fluorescence spectroscopy are extensively discussed for applications such as the analysis of paintings, manuscripts, pottery, etc. Here, we demonstrate for the first time the advantage of using both techniques for analysing glyptics. These engraved gemstones or glass materials were originally used as stamps, to identify the owner, for instance on letters, but also on wine vessels. For this research, a set of 64 glyptics (42 Roman glass specimens and 22 modern ones), belonging to the collection of the museum 'Quinta das Cruzes' in Funchal (Madeira, Portugal), was analysed with portable Raman spectroscopy and handheld X-ray fluorescence (hXRF). These techniques were also used to confirm the gemological identification of these precious objects and can give extra information about the glass composition. Raman spectroscopy identifies the molecular composition as well as on the crystalline phases present. On the other hand, hXRF results show that the antique Roman glass samples are characterised with low Pb and Sn levels and that the modern specimens can be discriminated in two groups: lead-based and non-lead-based ones. Copyright © 2015 Elsevier B.V. All rights reserved.
Gold Provenance Studies for Romanian Archaeological Objects Using Micro-SR-XRF
DOE Office of Scientific and Technical Information (OSTI.GOV)
Vasilescu, Angela; Constantinescu, Bogdan; Bugoi, Roxana
2010-04-06
Studies by Synchrotron Radiation--X-Ray Fluorescence (SR-XRF) for the search of the presence of trace elements like Sb, Sn, Te and Pb in archaeological metallic objects found on the territory of Romania--old coins and Bronze Age jewelry, aimed to determine the provenance of the gold used in their manufacture. The results are compared with the detailed elemental composition of alluvial or primary gold samples, obtained by the same technique. This work attempted to establish the origin of the gold used for the mint of two different types of koson coins. We found that the kosons with monogram are made of refinedmore » gold, while the one used for the kosons without monogram is mainly alluvial. The gold used in the manufacture of the Calarasi Vulchitrun-type disk and the Tauteu hair ring is also of alluvial origin.« less
NASA Astrophysics Data System (ADS)
Moravec, B. G.; White, A. M.; Paras, B.; Sanchez, A.; McGuffy, C.; Fairbanks, D.; McIntosh, J. C.; Pelletier, J. D.; Gallery, R. E.; Rasmussen, C.; Carr, B.; Holbrook, W. S.; Chorover, J.
2016-12-01
The Critical Zone (CZ) is the focus of current interdisciplinary Earth surface science research that aims to describe the interactions between geological and biological processes that influence ecosystem function, soil formation, nutrient and carbon cycling, hydrologic partitioning, biological activity and diversity, and mineral weathering. Prior research at the Catalina-Jemez (C-J) CZO has focused on the CZ near-surface, including remote sensing, and sampling/analysis of vegetation and soil microbiota, soils and saprolite, and surface water. However, the extent to which weathering, water/rock interaction, and solute mobility along flowpaths in the deep CZ respond to near surface CZ processes (i.e. water, energy, and mass fluxes) is not well understood. The goal of the present research is to understand depth-dependent trends in weathering dynamics from the mobile soil to unweathered bedrock in relation to landscape position (hillslope aspect and downgradient hollow). We used diamond core drilling techniques to excavate three boreholes to depths of 18.9, 41.8, and 46.3 meters in an instrumented forested sub-catchment of the C-J CZO in northern New Mexico. Here we present field methodology and preliminary data collected during the field campaign conducted during summer 2016. Element concentrations were measured during core extractions using portable X-ray fluorescence (XRF), which was subsequently validated against bench-scale XRF. Depth-dependent trends in both regolith depth and chemical depletion patterns show significant variation with landscape position. All three boreholes show complex weathering profiles with differences potentially due to textural controls on weathering, development of preferential flowpaths, and differing hydrologic base levels. Preliminary data indicate that chemical depletion patterns are not monotonic, but rather comprise large excursions that are being investigated for their relation to variation in local mineralogical composition and
NASA Astrophysics Data System (ADS)
Vaniman, David T.; Bish, D.; Guthrie, G.; Chipera, S.; Blake, David E.; Collins, S. Andy; Elliott, S. T.; Sarrazin, P.
1999-10-01
There is a large variety of mining and manufacturing operations where process monitoring and control can benefit from on-site analysis of both chemical and mineralogic constituents. CHEMIN is a CCD-based instrument capable of both X-ray fluorescence (XRF; chemical) and X-ray diffraction (XRD; mineralogic) analysis. Monitoring and control with an instrument like CHEMIN can be applied to feedstocks, intermediate materials, and final products to optimize production. Examples include control of cement feedstock, of ore for smelting, and of minerals that pose inhalation hazards in the workplace. The combined XRD/XRF capability of CHEMIN can be used wherever a desired commodity is associated with unwanted constituents that may be similar in chemistry or structure but not both (e.g., Ca in both gypsum and feldspar, where only the gypsum is desired to make wallboard). In the mining industry, CHEMIN can determine mineral abundances on the spot and enable more economical mining by providing the means to assay when is being mined, quickly and frequently, at minimal cost. In manufacturing, CHEMIN could be used to spot-check the chemical composition and crystalline makeup of a product at any stage of production. Analysis by CHEMIN can be used as feedback in manufacturing processes where rates of heating, process temperature, mixture of feedstocks, and other variables must be adjusted in real time to correct structure and/or chemistry of the product (e.g., prevention of periclase and alkali sulfate coproduction in cement manufacture).
NASA Astrophysics Data System (ADS)
Wulf, Sabine; Ott, Florian; Słowiński, Michał; Noryśkiewicz, Agnieszka M.; Dräger, Nadine; Martin-Puertas, Celia; Czymzik, Markus; Neugebauer, Ina; Dulski, Peter; Bourne, Anna J.; Błaszkiewicz, Mirosław; Brauer, Achim
2013-09-01
Tephrochronological studies of partly varved sediments of Trzechowskie palaeolake in central Northern Poland led to the finding of the Late Allerød Laacher See Tephra (LST) from the Eifel Volcanic Field for the first time in a very distal site ca 840 km ENE from its volcanic source. The detection of glass shards of the LST involved a comprehensive combination of techniques, i.e. biostratigraphical constrains, high-resolution μ-XRF core scanning and areal μ-XRF mapping of impregnated sediment slabs as well as detailed visual inspection of sediments. The major element chemistry of volcanic glass confirmed the Laacher See Tephra composition in Trzechowskie palaeolake sediments suggesting a deposition from the Middle Laacher See Tephra (MLST-C) or Upper Laacher See Tephra (ULST) dispersal fans. The finding of the LST in this palaeolake enables direct synchronisation with other high-resolution archives in north-central Europe (i.e., Lake Meerfelder Maar, Rehwiese palaeolake) to investigate regional variations of environmental responses at the onset of the Younger Dryas along a West-East transect through north-central Europe.
2D-3D μXRF elemental mapping of archeological samples
NASA Astrophysics Data System (ADS)
Hampai, D.; Liedl, A.; Cappuccio, G.; Capitolo, E.; Iannarelli, M.; Massussi, M.; Tucci, S.; Sardella, R.; Sciancalepore, A.; Polese, C.; Dabagov, S. B.
2017-07-01
Recently opened for users at LNF XLab-Frascati a μ XRF station, named "Rainbow X-ray" - RXR, has been optimized for most of X-ray analytical research fields. The basic principle of the station is in the use of various geometrical combinations of polycapillary optics for X-ray beam shaping (focusing/collimation) at specially designed laboratory unit. In this work we have presented the results of archaeological studies on the artifacts of Paleolithic period and Iron Age (9th century BC to the midway of the 8th BC). The elemental analysis of these artifacts has been first performed by compact laboratory setup. Superficial (2D) and bulk (3D) micro-fluorescence mapping provides useful informations for the geologists in order to identify the possible artifacts provenience and origin. The results presented in this work are a part of wider anthropological/archeological investigations aimed at the understanding of social and economical relations of prehistorical communities.
µ-XRF Studies on the Colour Brilliance in Ancient Wool Carpets
Meyer, Markus; Borca, Camelia N.; Huthwelker, Thomas; Bieber, Manfred; Meßlinger, Karl; Fink, Rainer H.
2017-01-01
Many handmade ancient and recent oriental wool carpets show outstanding brilliance and persistence of colour that is not achieved by common industrial dyeing procedures. Anthropologists have suggested the influence of wool fermentation prior to dyeing as key technique to achieve the high dyeing quality. By means of μ-XRF elemental mapping of mordant metals we corroborate this view and show a deep and homogenous penetration of colourants into fermented wool fibres. Furthermore we are able to apply this technique and prove that the fermentation process for ancient specimens cannot be investigated by standard methods due to the lack of intact cuticle layers. This finding suggests a broad range of further investigations that will contribute to a deeper understanding of the development of traditional dyeing techniques. Spectroscopic studies add information on the oxidation states of the metal ions within the respective mordant-dye-complexes and suggest a partial charge transfer as basis for a significant colour change when Fe mordants are used. PMID:29109824
NASA Astrophysics Data System (ADS)
Mucke, D.
2012-04-01
Heavy-metal contamination of soils in Saxony/Germany by foundry fumes and low-cost rapid analysis of contaminated soils by XRF Dieter Mucke, Rolf Kumann, Sebastian Baldauf GEOMONTAN Gesellschaft für Geologie und Bergbau mbH&Co.KG, Muldentalstrasse 56, 09603 Rothenfurth, Saxony/Germany For hundreds of years in the Ore Mountains between Bohemia and Saxony silver and other ores are produced and smelted. Sulphide- and sulpharsenide-ores needed to be roasted first. In doing so the sulphide sulphur was oxidised under formation of sulphur dioxide SO2 and arsenide conversed into elemental arsenic and arsenide trioxide As2O3 respectively. Also the metals lead, cadmium and zinc are components of hut smokes, in the field of nickel foundries also nickel. The contents of soils basically reflect the geogenic conditions, which are caused by decomposition- and relocation-effects of the mineralisations, in the area of foundries also with influences by with the hut smokes anthropogenic mobilised elements. The Saxonian Agency for Environment and Geology drafted in 1992 a Soil Investigation Program with the aim of investigation of the contamination of Saxonian soils with arsenic and toxic heavy metals. In order of this Agency GEOMONTAN investigated 1164 measuring points in the grid 4 * 4 km.soil profiles and extracted soil samples for analysis. In the result of the laboratory examinations the Agency edited the "Soil atlas of the Free State of Saxony". 27 elements, pH and PAK are shown in detailed maps and allow in whole Saxony the first assessment of the contamination of soils with arsenic and toxic heavy metals. Each of the investigated soil profiles represent an area of 16 km2. Already by the different use of the districts (agricultural, industrial, urban) restricts representative values. GEOMONTAN in the meantime used at the exploration of a copper deposit in Brandenburg/Germany with approx. 50,000 single tests at drill cores a very fast low-cost method: the X Ray fluorescence
Profiling of poorly stratified atmospheres with scanning lidar
C. E. Wold; V. A. Kovalev; A. P. Petkov; W. M. Hao
2012-01-01
The direct multiangle solution may allow inversion of the scanning lidar data even when the requirement of the horizontally stratified atmosphere is poorly met. The solution is based on two principles: (1) The signal measured in zenith is the core source for extracting the information about the atmospheric aerosol loading, and (2) The multiangle signals are used as...
NASA Astrophysics Data System (ADS)
Valerio, D. A.; Kulhanek, D. K.; Rosenthal, Y.; Holbourn, A. E.
2017-12-01
International Ocean Discovery Program (IODP) Expedition 363 sought to determine the nature of and driving forces behind climate variability in the Western Pacific Warm Pool (WPWP) region throughout the Neogene on millennial, orbital, and geologic timescales. Our research focuses on the Miocene (19-9 Ma) sediment record from IODP Site U1490 to examine changes in carbonate production and burial in the WPWP as a record of variations in the regional/global carbon cycle. This interval is of particular interest because it spans the Middle Miocene Climatic Optimum, the Middle Miocene Climate Transition, and the late Miocene carbonate crash. Site U1490 is located on the northern edge of Eauripik Rise at 05°58.95'N, 142°39.27'E in the northern part of the WPWP. At 2341 m water depth, today the site is bathed in Upper Circumpolar Deepwater. Miocene sediment at Site U1490 primarily consists of clay-bearing to clay-rich foraminifer-rich nannofossil ooze, although biogenic silica (primarily radiolaria) is a significant component in the lowermost part of the record. The sedimentation rate in the early to middle Miocene was very low (<1 cm/kyr), increasing to 1.6 cm/kyr in the late Miocene. Initial shipboard results show an average calcium carbonate content of 87 wt% throughout the site, with the most significant variations in the lower to middle Miocene, where contents range from 20 to 85 wt%. We collected X-ray fluorescence (XRF) data at 1 cm resolution along the composite stratigraphic section over the 19-9 Ma interval to obtain a qualitative measure of the bulk chemistry of the sediment. We will use the weight percent calcium carbonate of discrete samples to calibrate the XRF data to generate a high-resolution carbonate record. We observe cyclical variations in the Ca/Ba, which may reflect variations in productivity and/or dissolution through this interval, although additional work is needed to fully interpret these data. Ultimately our research will allow for comparison
NASA Technical Reports Server (NTRS)
Sarrazin, P.; Ming, D. W.; Morris, R. V.; Fernandez-Remolar, D.; Amils, R.; Arvidson, R. E.; Blake, D.; Bish, D. L.
2007-01-01
A field campaign was organized in September 2006 by Centro de Astobiologica (Spain) and Washington University (St Louis, USA) for the geological study of the Rio Tinto river bed sediments using a suite of in-situ instruments comprising an ASD reflectance spectrometer, an emission spectrometer, panoramic and close-up color imaging cameras, a life detection system and NASA's CheMin 4 XRD/XRF prototype. The primary objectives of the field campaign were to study the geology of the site and test the potential of the instrument suite in an astrobiological investigation context for future Mars surface robotic missions. The results of the overall campaign will be presented elsewhere. This paper focuses on the results of the XRD/XRF instrument deployment. The specific objectives of the CheMin 4 prototype in Rio Tinto were to 1) characterize the mineralogy of efflorescent salts in their native environments; 2) analyze the mineralogy of salts and oxides from the modern environment to terraces formed earlier as part of the Rio Tinto evaporative system; and 3) map the transition from hematite-dominated terraces to the mixed goethite/salt-bearing terraces where biosignatures are best preserved.
NASA Astrophysics Data System (ADS)
Zimmerman, S. R.; Starratt, S.; Hemming, S. R.
2012-12-01
Mono Lake, California is a closed-basin lake on the east side of the Sierra Nevada, and inflow from snowmelt dominates the modern hydrology. Changes in wetness during the last glacial period (>12,000 years ago) and over the last 2,000 years have been extensively described, but are poorly known for the intervening period. We have recovered a 6.25 m-long core from ~3 m of water in the western embayment of Mono Lake, which is shown by initial radiocarbon dates to cover at least the last 10,000 years. The sediments of the core are variable, ranging from black to gray silts near the base, laminated olive-green silt through the center, to layers of peach-colored carbonate nodules interbedded with gray and olive silts and pea-green organic ooze. Volcanic tephras from <1 to 8 cm thick occur throughout. Results of 0.5 cm-resolution scanning-X-Ray fluoresence (XRF) analysis describe changes in lithology due to volcanism, erosion, and changing lake level and chemistry. Titanium (Ti) is chemically and biologically unreactive, and records the dominant input, from weathering of Sierra Nevada granite to the west and Miocene and Pliocene volcanic rocks of the Bodie and Adobe Hills to the north, east, and south. The rhyolitic tephras of the Mono-Inyo Craters are much lower in TiO2 than the bedrock (<0.1% vs. 1-2%), and are an unweathered source of K2O (3.5-5%), and thus form dramatic peaks in the K/Ti ratio. Calcium (Ca) and Sr are well correlated throughout the core, and normalization of both by K (detritus + tephra) corresponds with occurrence of carbonate-rich layers. These are a mixture of authigenic precipitates directly precipitated and eroded into the lake during periods of regression. The lowermost 1.5 m of the BINGO core contains the highest proportion of detrital input to Mono Lake over the last ~12,000 years, recorded by high Si, Ti, K, and Fe, in black to dark-gray, fine-grained silts above 10 cm of pure light gray silt. Based on radiocarbon dates of >10,000 calibrated
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bobyshev, A.; Lamore, D.; Demar, P.
2004-12-01
In a large campus network, such at Fermilab, with tens of thousands of nodes, scanning initiated from either outside of or within the campus network raises security concerns. This scanning may have very serious impact on network performance, and even disrupt normal operation of many services. In this paper we introduce a system for detecting and automatic blocking excessive traffic of different kinds of scanning, DoS attacks, virus infected computers. The system, called AutoBlocker, is a distributed computing system based on quasi-real time analysis of network flow data collected from the border router and core switches. AutoBlocker also has anmore » interface to accept alerts from IDS systems (e.g. BRO, SNORT) that are based on other technologies. The system has multiple configurable alert levels for the detection of anomalous behavior and configurable trigger criteria for automated blocking of scans at the core or border routers. It has been in use at Fermilab for about 2 years, and has become a very valuable tool to curtail scan activity within the Fermilab campus network.« less
Turner, Andrew; Comber, Sean; Rees, Aldous B; Gkiokas, Dimitrios; Solman, Kevin
2015-01-01
Paint flaking off abandoned vessels or generated during boat repair is hazardous to human health and wildlife. In this study, a means of screening paint fragments using a field portable-X-ray fluorescence (FP-XRF) spectrometer is described. The technique is capable of delivering rapid, surficial measurements of Ba, Cu, Pb and Zn down to concentrations less than 150 μg g(-1), and Sn and Cr to concentrations of a few hundred μg g(-1). Application of the technique to fragments collected from slipways, yards, hardstandings, abandoned boats and ships undergoing maintenance throughout the EU reveal highly variable concentrations of metals among samples from the same environment or from the same region of a given boat; in many cases, variability is also evident in different areas or on different surfaces of the same fragment. Of particular concern are elevated concentrations of substances that have been restricted or banned (e.g. Sn, an indicator of organotin, and up to concentrations of 40,000 μg g(-1), and Pb up to concentrations of 200,000 μg g(-1)). Although FP-XRF can rapidly screen samples whose composition and origin are unknown and can assist in instantaneous decision making, a full risk assessment will rely on additional analyses of the precise species (including organo-forms) of the metals present. Copyright © 2014 Elsevier B.V. All rights reserved.
NASA Astrophysics Data System (ADS)
Pan, H. J.; Chen, M. T.
2014-12-01
Heavy summer monsoon rainfall along with typhoon-induced extreme precipitation cause frequent geological hazards that often threaten the human's safety and property in Taiwan. These geological hazards can be triggered by both natural factors, and/or have become deteriorated by perturbations from more and more human activities ever since few thousand years ago. However, due to the limit of instrumental records for observing long-term environmental changes in Taiwan, few evidence exist for distinguishing the human-induced impacts from natural climate change. Here we report a study on a high quality marine sediment core (MD103264) which were retrieved from the high sedimentation rate area from offshore southwestern Taiwan and present evidence for the long-term climate and possibly human-induced environmental changes since the last glacial. We are using the VIS-NIR Diffuse Reflectance Spectrophotometry (DRS) methods to study the cores. Interpreting the VIS-NIR reflectance spectra through the VARIMAX-rotation, principle component analysis (VPCA) helps conducting rapid and inexpensive measurements for acquiring high-resolution biogenic component, clay, and iron oxide mineral compositional data from the cores. We are also using X-Ray Fluorescence (XRF) analysis, which is also useful in determining the element compositional changes in the core. Our studies aim toward understanding the sediment and element compositional changes that reflect the patterns of changes in precipitation and soil erosion on land since the last glacial to the Holocene, during which the human activities (deforestation, agriculture, and land uses change) may have increased drastically. We will report and interpret the preliminary results of the optical analyses of the core.
Alanine scan of core positions in ubiquitin reveals links between dynamics, stability, and function
Lee, Shirley Y.; Pullen, Lester; Virgil, Daniel J.; Castañeda, Carlos A.; Abeykoon, Dulith; Bolon, Daniel N. A.; Fushman, David
2014-01-01
Mutations at solvent inaccessible core positions in proteins can impact function through many biophysical mechanisms including alterations to thermodynamic stability and protein dynamics. As these properties of proteins are difficult to investigate, the impacts of core mutations on protein function are poorly understood for most systems. Here, we determined the effects of alanine mutations at all 15 core positions in ubiquitin on function in yeast. The majority (13 of 15) of alanine substitutions supported yeast growth as the sole ubiquitin. The two null mutants (I30A and L43A) were both less stable to temperature-induced unfolding in vitro than wild-type, but were well folded at physiological temperatures. Heteronuclear NMR studies indicated that the L43A mutation reduces temperature stability while retaining a ground-state structure similar to wild-type. This structure enables L43A to bind to common ubiquitin receptors in vitro. Many of the core alanine ubiquitin mutants, including one of the null variants (I30A), exhibited an increased accumulation of high molecular weight species, suggesting that these mutants caused a defect in the processing of ubiquitin-substrate conjugates. In contrast, L43A exhibited a unique accumulation pattern with reduced levels of high molecular weight species and undetectable levels of free ubiquitin. When conjugation to other proteins was blocked, L43A ubiquitin accumulated as free ubiquitin in yeast. Based on these findings we speculate that ubiquitin's stability to unfolding may be required for efficient recycling during proteasome-mediated substrate degradation. PMID:24361330
Portable X-ray diffractometer equipped with XRF for archaeometry
NASA Astrophysics Data System (ADS)
Uda, M.; Ishizaki, A.; Satoh, R.; Okada, K.; Nakajima, Y.; Yamashita, D.; Ohashi, K.; Sakuraba, Y.; Shimono, A.; Kojima, D.
2005-09-01
A portable X-ray diffractometer equipped with an X-ray fluorescence spectrometer was improved so as to get a diffraction pattern and a fluorescence spectrum simultaneously in air from one and the same small area on a specimen. Here, diffraction experiments were performed in two modes, i.e. an angle rotation mode and an energy dispersive mode. In the latter a diffraction pattern and a fluorescence spectrum were simultaneously recorded in a short time, 100 s or less, on one display. The diffractometer was tested in the field to confirm its performance. Targets chosen for this purpose were a bronze mirror from the Eastern Han Dynasty (25-220), and a stupa and its pedestal which are part of the painted statue of "Tamonten holding a stupa" from the Heian Period (794-1192), enshrined in the Engyouji temple founded in 996. The bronze mirror was identified as a product of the Han Dynasty from its chemical composition and the existence of the δ phase in the Cu-Sn alloy. The stupa and its pedestal were decorated with gold powder and gold leaf, respectively. From the XRF data of the pedestal, the underlying layer of gold leaf seems to have been painted with emerald green.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Stoker, J; Summers, P; Li, X
2014-06-01
Purpose: This study seeks to evaluate the dosimetric effects of intra-fraction motion during spot scanning proton beam therapy as a function of beam-scan orientation and target motion amplitude. Method: Multiple 4DCT scans were collected of a dynamic anthropomorphic phantom mimicking respiration amplitudes of 0 (static), 0.5, 1.0, and 1.5 cm. A spot-scanning treatment plan was developed on the maximum intensity projection image set, using an inverse-planning approach. Dynamic phantom motion was continuous throughout treatment plan delivery.The target nodule was designed to accommodate film and thermoluminescent dosimeters (TLD). Film and TLDs were uniquely labeled by location within the target. The phantommore » was localized on the treatment table using the clinically available orthogonal kV on-board imaging device. Film inserts provided data for dose uniformity; TLDs provided a 3% precision estimate of absolute dose. An inhouse script was developed to modify the delivery order of the beam spots, to orient the scanning direction parallel or perpendicular to target motion.TLD detector characterization and analysis was performed by the Imaging and Radiation Oncology Core group (IROC)-Houston. Film inserts, exhibiting a spatial resolution of 1mm, were analyzed to determine dose homogeneity within the radiation target. Results: Parallel scanning and target motions exhibited reduced target dose heterogeneity, relative to perpendicular scanning orientation. The average percent deviation in absolute dose for the motion deliveries relative to the static delivery was 4.9±1.1% for parallel scanning, and 11.7±3.5% (p<<0.05) for perpendicularly oriented scanning. Individual delivery dose deviations were not necessarily correlated to amplitude of motion for either scan orientation. Conclusions: Results demonstrate a quantifiable difference in dose heterogeneity as a function of scan orientation, more so than target amplitude. Comparison to the analyzed planar dose of a
XRF map identification problems based on a PDE electrodeposition model
NASA Astrophysics Data System (ADS)
Sgura, Ivonne; Bozzini, Benedetto
2017-04-01
In this paper we focus on the following map identification problem (MIP): given a morphochemical reaction-diffusion (RD) PDE system modeling an electrodepostion process, we look for a time t *, belonging to the transient dynamics and a set of parameters \\mathbf{p} , such that the PDE solution, for the morphology h≤ft(x,y,{{t}\\ast};\\mathbf{p}\\right) and for the chemistry θ ≤ft(x,y,{{t}\\ast};\\mathbf{p}\\right) approximates a given experimental map M *. Towards this aim, we introduce a numerical algorithm using singular value decomposition (SVD) and Frobenius norm to give a measure of error distance between experimental maps for h and θ and simulated solutions of the RD-PDE system on a fixed time integration interval. The technique proposed allows quantitative use of microspectroscopy images, such as XRF maps. Specifically, in this work we have modelled the morphology and manganese distributions of nanostructured components of innovative batteries and we have followed their changes resulting from ageing under operating conditions. The availability of quantitative information on space-time evolution of active materials in terms of model parameters will allow dramatic improvements in knowledge-based optimization of battery fabrication and operation.
Development of core-shell coaxially electrospun composite PCL/chitosan scaffolds.
Surucu, Seda; Turkoglu Sasmazel, Hilal
2016-11-01
This study was related to combining of synthetic Poly (ε-caprolactone) (PCL) and natural chitosan polymers to develop three dimensional (3D) PCL/chitosan core-shell scaffolds for tissue engineering applications. The scaffolds were fabricated with coaxial electrospinning technique and the characterizations of the samples were done by thickness and contact angle (CA) measurements, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-Ray Photoelectron Spectroscopy (XPS) analyses, mechanical and PBS absorption and shrinkage tests. The average inter-fiber diameter values were calculated for PCL (0.717±0.001μm), chitosan (0.660±0.007μm) and PCL/chitosan core-shell scaffolds (0.412±0.003μm), also the average inter-fiber pore size values exhibited decreases of 66.91% and 61.90% for the PCL and chitosan scaffolds respectively, compared to PCL/chitosan core-shell ones. XPS analysis of the PCL/chitosan core-shell structures exhibited the characteristic peaks of PCL and chitosan polymers. The cell culture studies (MTT assay, Confocal Laser Scanning Microscope (CLSM) and SEM analyses) carried out with L929 ATCC CCL-1 mouse fibroblast cell line proved that the biocompatibility performance of the scaffolds. The obtained results showed that the created micro/nano fibrous structure of the PCL/chitosan core-shell scaffolds in this study increased the cell viability and proliferation on/within scaffolds. Copyright © 2016 Elsevier B.V. All rights reserved.
NASA Technical Reports Server (NTRS)
Chipera, S. J.; Vaniman, D. T.; Bish, D. L.; Sarrazin, P.; Feldman, S.; Blake, D. F.; Bearman, G.; Bar-Cohen, Y.
2004-01-01
A miniature XRD/XRF (X-ray diffraction / X-ray fluorescence) instrument, CHEMIN, is currently being developed for definitive mineralogic analysis of soils and rocks on Mars. One of the technical issues that must be addressed to enable remote XRD analysis is how best to obtain a representative sample powder for analysis. For powder XRD analyses, it is beneficial to have a fine-grained sample to reduce preferred orientation effects and to provide a statistically significant number of crystallites to the X-ray beam. Although a two-dimensional detector as used in the CHEMIN instrument will produce good results even with poorly prepared powder, the quality of the data will improve and the time required for data collection will be reduced if the sample is fine-grained and randomly oriented. A variety of methods have been proposed for XRD sample preparation. Chipera et al. presented grain size distributions and XRD results from powders generated with an Ultrasonic/Sonic Driller/Corer (USDC) currently being developed at JPL. The USDC was shown to be an effective instrument for sampling rock to produce powder suitable for XRD. In this paper, we compare powder prepared using the USDC with powder obtained with a miniaturized rock crusher developed at JPL and with powder obtained with a rotary tungsten carbide bit to powders obtained from a laboratory bench-scale Retsch mill (provides benchmark mineralogical data). These comparisons will allow assessment of the suitability of these methods for analysis by an XRD/XRF instrument such as CHEMIN.
NASA Astrophysics Data System (ADS)
Silva, T. A.; Girardclos, S.; Loizeau, J. L.
2016-12-01
Lake sediment records are often the most complete continental archives. In the last 200 years, in addition to climatic variability, humans have strongly impacted lake watersheds around the world. During the 20th century the Rhone River and its watershed upstream Lake Geneva (Switzerland/France) have been subject to river channelization, dam construction, water flow regulation, water and sediment abstraction as well as various land use changes. Under the scope of the SEDFATE project (Swiss National Science Foundation nº147689) we address human and climatic impact on the sediment transfer from the Rhone River watershed to Lake Geneva. Nineteen short sediment cores were collected in the Rhone River delta area in May 2014. Cores have been scanned with MSCL and XRF, sub-sampled every 1cm and 8 cores were dated by radiometric methods (137Cs and 210Pb). Photographs taken right after core opening were used for lithological description and in addition to MSCL data were used to correlate cores. Core dating shows that mass accumulation rates decreased in the 1964-1986 interval and then increased again in the interval between 1986-2014. XRF elements and ratios, known to indicate detrital sources (Al, Al/Si, Fe, K, Mn, Rb, Si, Ti, Ti/Ca), show that clastic input diminished from 1964 to 1986 and re-increased to the present. Other elemental (Zr/Rb, Zr/K, Si/Ti) and geophysical data (magnetic susceptibility) combined with lithology identify density flow deposits vs hemipelagic sedimentation. Changes in frequency of these event deposits indicate changes in the sedimentation patterns in the Rhone River sublacustrine delta during the last century. From these results we hypothesize that a significant sediment amount was abstracted from the system after the major dam constructions in the 1950's and that, since the 1990's, a contrary signal is due to increased sediment loads that follows glacial melting due to global warming.
Morishige, Ashley E.; Laine, Hannu S.; Looney, Erin E.; ...
2017-04-03
Optimizing photovoltaic (PV) devices requires characterization and optimization across several length scales, from centimeters to nanometers. Synchrotron-based micro-X-ray fluorescence spectromicroscopy (μ-XRF) is a valuable link in the PV-related material and device characterization suite. μ-XRF maps of elemental distributions in PV materials have high spatial resolution and excellent sensitivity and can be measured on absorber materials and full devices. Recently, we implemented on-the-fly data collection (flyscan) at Beamline 2-ID-D at the Advanced Photon Source at Argonne National Laboratory, eliminating a 300 ms per-pixel overhead time. This faster scanning enables high-sensitivity (~10 14 atoms/cm 2), large-area (10 000s of μm 2), high-spatialmore » resolution (<;200 nm scale) maps to be completed within a practical scanning time. We specifically show that when characterizing detrimental trace metal precipitate distributions in multicrystalline silicon wafers for PV, flyscans can increase the productivity of μ-XRF by an order of magnitude. Additionally, flyscan μ-XRF mapping enables relatively large-area correlative microscopy. As an example, we map the transition metal distribution in a 50 μm-diameter laser-fired contact of a silicon solar cell before and after lasing. As a result, while we focus on μ-XRF of mc-Si wafers for PV, our results apply broadly to synchrotron-based mapping of PV absorbers and devices.« less
In vivo evaluation of Fe in human skin employing X-Ray Fluorescence Methodology (XRF)
NASA Astrophysics Data System (ADS)
Estevam, M.; Appoloni, C. R.
2007-02-01
Recent technological improvements allow the method of in vivo XRF to provide useful sensibility for diagnostics or monitoring in biomedical applications. In cases of hereditary sanguine disorders as the β-thalassaemia or a genetic disorder like Haemochromatosis, there is a high concentration of elements as Fe, Zn and Cu in the skin and internal organs, due to the treatment of those abnormalities or due to the own dysfunction caused by the disease. The levels of Fe related to the patient bearers of the β-thalassaemia are determined, at the moment, measuring a protein in the sanguine current, called ferritin. The monitoring of the protein is ineffective in several situations, such as when the patient suffers any disturbance of health. Nowadays, the main forms of measuring the levels of those metals through hepatic storage are the biopsy of the liver, that is invasive and potentially dangerous, presenting a rate of mortality of 0.1%, and by means of magnetic susceptibilities that employs a quantum superconductor, which is highly expensive and there are only three main world centers with this equipment This work investigates the use of a Si PIN-diode detector and a 238Pu source (13 and 17keV; 13%; 95.2mCi; 86y) for the measurement of Fe skin levels compatible with those associated to the disease β-thalassaemia. XRF spectra were analyzed using a set of AXIL-WinQXAS programs elaborated and disseminated by the IAEA. The determination coefficient of the calibration model (sensitivity curve) was 0.97. Measurements on skin phantoms containing concentrations of Fe in the range from 10 to 150 parts per million (ppm), indicate that we are able to detect Fe at levels of the order of 15ppm, using monitoring periods of 50 seconds and skin entrance dose less than 10 mSv, The literature reports skin Fe levels from 15.0 to 60.0 ppm in normal persons and from 70 to 150 ppm in thalassaemics patients. So, the employed methodology allows the measurement of the skin Fe concentration.
Structural Basis for Near Unity Quantum Yield Core/Shell Nanostructures
DOE Office of Scientific and Technical Information (OSTI.GOV)
McBride, James; Treadway, Joe; Pennycook, Stephen J
2006-01-01
Aberration-corrected Z-contrast scanning transmission electron microscopy of core/shell nanocrystals shows clear correlations between structure and quantum efficiency. Uniform shell coverage is obtained only for a graded CdS/ZnS shell material and is found to be critical to achieving near 100% quantum yield. The sublattice sensitivity of the images confirms that preferential growth takes place on the anion-terminated surfaces. This explains the three-dimensional "nanobullet" shape observed in the case of core/shell nanorods.
NASA Astrophysics Data System (ADS)
Lindner, T.; Bonebeau, S.; Drehmann, R.; Grund, T.; Pawlowski, L.; Lampke, T.
2016-03-01
In wire arc spraying, the raw material needs to exhibit sufficient formability and ductility in order to be processed. By using an electrically conductive, metallic sheath, it is also possible to handle non-conductive and/or brittle materials such as ceramics. In comparison to massive wire, a cored wire has a heterogeneous material distribution. Due to this fact and the complex thermodynamic processes during wire arc spraying, it is very difficult to predict the resulting chemical composition in the coating with sufficient accuracy. An Inconel 625 cored wire was used to investigate this issue. In a comparative study, the analytical results of the raw material were compared to arc sprayed coatings and droplets, which were remelted in an arc furnace under argon atmosphere. Energy-dispersive X-ray spectroscopy (EDX) and X-ray fluorescence (XRF) analysis were used to determine the chemical composition. The phase determination was performed by X-ray diffraction (XRD). The results were related to the manufacturer specifications and evaluated in respect to differences in the chemical composition. The comparison between the feedstock powder, the remelted droplets and the thermally sprayed coatings allows to evaluate the influence of the processing methods on the resulting chemical and phase composition.
NASA Technical Reports Server (NTRS)
Feldman, S. M.; Blake, D. F.; Sarrazin, P.; Bish, D. L.; Chipera, S. J.; Vaniman, D. T.; Collins, S.
2004-01-01
The search for evidence of habitability, or of extant or extinct life on Mars, will initially be a search for evidence of past or present conditions supportive of life. The three key requirements for the emergence of life are thought to be liquid water; a suitable energy source; and chemical building blocks. CheMin is a miniaturized XRD/XRF (X-Ray diffraction / X-ray fluorescence) instrument which has been developed for definitive mineralogic analysis of soils and rocks on the Martian surface. The CheMin instrument can provide information that is highly relevant to each of these habitability requirements as summarized below.
Preliminary Results From the Chicxulub Post-Impact Sediments: XRF and Physical Properties Data
NASA Astrophysics Data System (ADS)
Gebhardt, C.; Perez-Cruz, L. L.; Chenot, É.; Christeson, G. L.; Le Ber, E.; Lofi, J.; Nixon, C.; Rae, A.; Expedition 364 Science Party, I. I.
2017-12-01
In spring 2016, joint IODP/ICDP Expedition 364 drilled into the peak ring of the Chicxulub crater, offshore the Yucatan Peninsula, Mexico. A continuous core was drilled (Hole M0077A) and recovered a sequence of Paleogene post-impact rocks, suevites, impact-melt rocks and granitic basement between 505.7 m and 1334.7 m below sea floor (bsf). The Chicxulub crater was formed 66 million years ago by an impact. This catastrophic event was directly linked to a major mass extinction. For this study, we concentrate on the post-impact sediments (505.7 to 617.3 m bsf; 48 to 66 Ma). The main goal of drilling the post-impact section was to study the pace and mode of recovery of life in the ocean after the impact, and to analyze the paleoenvironmental changes across the Paleocene and Eocene. The late Paleocene and Eocene are characterized by a series of transient warming events, so-called hyperthermals that were associated with increased atmospheric pCO2. Here, we present preliminary geochemical and physical properties data from the 112 m of Paleogene sediments. XRF data show high log (Ca/Ti) values between 617 and 598 m bsf (Paleocene and early Eocene), and lower values between 598 and 505 m bsf. In particular the upper part is characterized by high-frequency fluctuations in log (Ca/Ti) reflecting repeated changes in lithology. These were presumably caused by Milankovitch cycles. Low log (Ba/Ti) values characterize the lowermost part of the record between 617 and 610, followed by a gradual increase to higher values, presumably indicating an increase in primary productivity towards the end of the Paleocene. Values remain at this higher level between 605 and 540 m bsf. Hyperthermals are characterized by strong positive log (Ba/Ti) peaks, likely pointing at highly elevated primary productivity levels during these short-lived events. Between 540 and 505 m bsf, log (Ba/Ti) values are more variable and drop occasionally to values as low as were encountered in the lowermost part
A scanning tunneling microscope for a dilution refrigerator.
Marz, M; Goll, G; Löhneysen, H v
2010-04-01
We present the main features of a home-built scanning tunneling microscope that has been attached to the mixing chamber of a dilution refrigerator. It allows scanning tunneling microscopy and spectroscopy measurements down to the base temperature of the cryostat, T approximately 30 mK, and in applied magnetic fields up to 13 T. The topography of both highly ordered pyrolytic graphite and the dichalcogenide superconductor NbSe(2) has been imaged with atomic resolution down to T approximately 50 mK as determined from a resistance thermometer adjacent to the sample. As a test for a successful operation in magnetic fields, the flux-line lattice of superconducting NbSe(2) in low magnetic fields has been studied. The lattice constant of the Abrikosov lattice shows the expected field dependence proportional to 1/square root of B and measurements in the scanning tunneling spectroscopy mode clearly show the superconductive density of states with Andreev bound states in the vortex core.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Wawrzynczyk, Dominika; Szeremeta, Janusz; Samoc, Marek
Spectrally resolved nonlinear optical properties of colloidal InP@ZnS core-shell quantum dots of various sizes were investigated with the Z-scan technique and two-photon fluorescence excitation method using a femtosecond laser system tunable in the range from 750 nm to 1600 nm. In principle, both techniques should provide comparable results and can be interchangeably used for determination of the nonlinear optical absorption parameters, finding maximal values of the cross sections and optimizing them. We have observed slight differences between the two-photon absorption cross sections measured by the two techniques and attributed them to the presence of non-radiative paths of absorption or relaxation.more » The most significant value of two-photon absorption cross section σ{sub 2} for 4.3 nm size InP@ZnS quantum dot was equal to 2200 GM, while the two-photon excitation action cross section σ{sub 2}Φ was found to be 682 GM at 880 nm. The properties of these cadmium-free colloidal quantum dots can be potentially useful for nonlinear bioimaging.« less
NASA Astrophysics Data System (ADS)
Wawrzynczyk, Dominika; Szeremeta, Janusz; Samoc, Marek; Nyk, Marcin
2015-11-01
Spectrally resolved nonlinear optical properties of colloidal InP@ZnS core-shell quantum dots of various sizes were investigated with the Z-scan technique and two-photon fluorescence excitation method using a femtosecond laser system tunable in the range from 750 nm to 1600 nm. In principle, both techniques should provide comparable results and can be interchangeably used for determination of the nonlinear optical absorption parameters, finding maximal values of the cross sections and optimizing them. We have observed slight differences between the two-photon absorption cross sections measured by the two techniques and attributed them to the presence of non-radiative paths of absorption or relaxation. The most significant value of two-photon absorption cross section σ2 for 4.3 nm size InP@ZnS quantum dot was equal to 2200 GM, while the two-photon excitation action cross section σ2Φ was found to be 682 GM at 880 nm. The properties of these cadmium-free colloidal quantum dots can be potentially useful for nonlinear bioimaging.
Construction of digital core by adaptive porosity method
NASA Astrophysics Data System (ADS)
Xia, Huifen; Liu, Ting; Zhao, Ling; Sun, Yanyu; Pan, Junliang
2017-05-01
The construction of digital core has its unique advantages in the study of water flooding or polymer flooding oil displacement efficiency. The frequency distribution of pore size is measured by mercury injection experiment, the coordination number by CT scanning method, and the wettability data by imbibition displacement was measured, on the basis of considering the ratio of pore throat ratio and wettability, the principle of adaptive porosity is used to construct the digital core. The results show that the water flooding recovery, the degree of polymer flooding and the results of the Physical simulation experiment are in good agreement.
NASA Astrophysics Data System (ADS)
Hebert, V.; Garing, C.; Pezard, P. A.; Gouze, P.; Maria-Sube, Y.; Camoin, G.; Lapointe, P.
2009-04-01
Petrophysical properties of rocks can be largely influenced by heterogeneities. This is particularly true in reefal carbonates, with heterogeneities due to the primary structure of the reef, the degradation of that structure into a fossil form, and fluid circulations with associated dissolutions and recrystallization. We report here a study conducted on Miocene reefal carbonates drilled in the context of salt water intrusion in coastal reservoirs. Salt water intrusion along coastlines is highly influenced by geological and petrophysical structures. In particular, heterogeneities and anisotropy in porous media (karsts, vugs…) control fluid flow and dispersion. A new experimental site has been developed in the South East of Mallorca Island (Spain) in the context of the ALIANCE EC project (2002-2005). This project aimed at developing a strategy for the quantitative analysis and description of fluid flow and salt transport in coastal carbonate aquifers. The site drilled the Miocene carbonate reef platform at Ses Sitjoles, 6 km inland, near the city of Campos. Sea water is found there at 60 to 80 m depth. The geological structure present multi-scale heterogeneities, often bound to either lateral variations of geological facies, or dissolution patterns. The Campos site provides a unique laboratory to study the heterogeneities of carbonate rocks with a saltwater intrusion and develop new borehole investigation methods in this context. The present study focuses on borehole geophysical measurements and images, and core scans. New image analysis methods have been developed to better characterize the presence of heterogeneities in terms of grain-size distribution, formation factor changes and porosity. Cores scans from RX tomography can lead to the extraction of petrophysical parameters from 3D images. For this, the AVIZO software was used here to represent the micro-porosity and vuggy porosity structure. Beyond core analyses, the optical and acoustic borehole wall images
Core-core and core-valence correlation
NASA Technical Reports Server (NTRS)
Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Taylor, Peter R.
1988-01-01
The effect of (1s) core correlation on properties and energy separations was analyzed using full configuration-interaction (FCI) calculations. The Be 1 S - 1 P, the C 3 P - 5 S and CH+ 1 Sigma + or - 1 Pi separations, and CH+ spectroscopic constants, dipole moment and 1 Sigma + - 1 Pi transition dipole moment were studied. The results of the FCI calculations are compared to those obtained using approximate methods. In addition, the generation of atomic natural orbital (ANO) basis sets, as a method for contracting a primitive basis set for both valence and core correlation, is discussed. When both core-core and core-valence correlation are included in the calculation, no suitable truncated CI approach consistently reproduces the FCI, and contraction of the basis set is very difficult. If the (nearly constant) core-core correlation is eliminated, and only the core-valence correlation is included, CASSCF/MRCI approached reproduce the FCI results and basis set contraction is significantly easier.
NASA Astrophysics Data System (ADS)
Schaebitz, F.; Asrat, A.; Lamb, H. F.; Trauth, M. H.; Junginger, A.; Foerster, V. E.; Guenter, C.; Viehberg, F. A.; Just, J.; Roberts, H. M.; Chapot, M. S.; Leng, M. J.; Dean, J.; Cohen, A. S.
2016-12-01
Chew Bahir is a tectonic basin in the southern Ethiopian Rift, close to the Lower Omo valley, site of earliest known fossil of anatomically modern humans. It was drilled in Nov-Dec 2014 as part of the Hominin Sites and Paleolakes Drilling Project (HSPDP) and the Collaborative Research Center (CRC806) "Our Way to Europe". Two overlapping cores of mostly clayey silts, reaching a composite depths of 280m, were collected and may cover the last 500,000 years, thus providing a potential record of environmental history during the evolution and spread of anatomically modern humans. Here we present the lithology and stratigraphy of the composite core as well as results of high resolution MSCL and XRF scanning data. Initial sedimentological and geochemical results show that the Chew Bahir deposits are a sensitive record of changes in moisture, sediment influx, provenance, transport and diagenetic processes, evident from mineralogy, elemental concentration and physical properties. The potassium record is highly sensitive to changes in moisture balance (Foerster et al. 2015). XRF and XRD data suggest that the process linking climate with potassium concentrations is the diagenetic illitization of smectites during dry episodes with high alkalinity and salinity in the closed-basin lake. The core records will allow tests of the various hypotheses about the influence of environmental change on the evolution and dispersal of anatomically modern humans. Foerster, V., Vogelsang, R., Junginger, A., Asrat, A., Lamb, H.F., Schaebitz, F., Trauth, M.H. (2015): Environmental Change and Human Occupation of Southern Ethiopia and Northern Kenya during the last 20,000 years. Quaternary Science Reviews, 129: 333-340. doi:10.1016/j.quascirev.2015.10.026.
100-OL-1 Operable Unit Field Portable X-Ray Fluorescence (XRF) Analyzer Pilot Study Plans
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bunn, Amoret L.; Fritz, Brad G.; Wellman, Dawn M.
A pilot study is being conducted to support the approval of the Remedial Investigation/Feasibility Study (RI/FS) Work Plan to evaluate the 100-OL-1 Operable Unit (OU) pre-Hanford orchard lands. Based on comments received by the U.S. Environmental Protection Agency (EPA) and Washington State Department of Ecology, the pilot study will evaluate the use of field portable X-ray fluorescence (XRF) spectrometry measurements for evaluating lead and arsenic concentrations on the soil surface as an indicator of past use of lead arsenate pesticide residue in the OU. The work will be performed in the field during the summer of 2014, and assist inmore » the planning for the characterization activities in the RI/FS.« less
NASA Astrophysics Data System (ADS)
János, I.; Szathmáry, L.; Nádas, E.; Béni, A.; Dinya, Z.; Máthé, E.
2011-11-01
The present study is a multielemental analysis of bone samples belonging to skeletal individuals originating from two contemporaneous (10th century AD) cemeteries (Tiszavasvári Nagy-Gyepáros and Nagycserkesz-Nádasibokor sites) in Northeastern Hungary, using the XRF analytical technique. Emitted X-rays were detected in order to determine the elemental composition of bones and to appreciate the possible influence of the burial environment on the elemental content of the human skeletal remains. Lumbar vertebral bodies were used for analysis. Applying the ED(P)XRF technique concentration of the following elements were determined: P, Ca, K, Na, Mg, Al, Cl, Mn, Fe, Zn, Br and Sr. The results indicated post mortem mineral exchange between the burial environment (soil) and bones (e.g. the enhanced levels of Fe and Mn) and referred to diagenetic alteration processes during burials. However, other elements such as Zn, Sr and Br seemed to be accumulated during the past life. On the basis of statistical analysis, clear separation could not be observed between the two excavation sites in their bone elemental concentrations which denoted similar diagenetic influences, environmental conditions. The enhanced levels of Sr might be connected with the past dietary habits, especially consumption of plant food.
NASA Astrophysics Data System (ADS)
Stremtan, Ciprian; Ashkanani, Hasan; Tykot, Robert H.
2013-04-01
The study of bi-phase (i.e. matrix and clasts) geochemical composition of ceramic artifacts is a very powerful tool in fingerprinting the raw materials used by ancient manufacturers (clay sources, tempering materials, coloring agents, etc.), as well as in understanding the physical parameters of the manufacturing techniques. Reliable datasets often require the deployment of destructive techniques that will irremediably damage the artifact. Recent advances in portable X-ray fluorescence instrumentation (pXRF) allow for quick measurements of a range of chemical elements that not too long ago were available only through complicated and often destructive means of analytical chemistry (instrumental neutron activation analysis - INAA, inductively coupled plasma mass spectrometry - ICP-MS, direct coupled plasma-optical emission spectroscopy - DCP-OES etc.). In this contribution we present a comparison of datasets acquired by means of pXRF, DCP-OES, and ICP-MS on Bronze Age ceramics from Failaka Island (Kuwait) and Bahrain. The samples chosen for this study are fine grained, with very well sorted mineral components, and lack any visible organic material fragments. The sample preparation for ICP-MS and DCP-OES analyses was carried out on powdered samples, by using LiBO2 flux fusion and Ge (for the DCP-OES) and In (for ICP-MS) were used as internal standards. The measurements were calibrated against certified reference materials ranging from shales to rhyolites (SGR-1, SDo-1, JA-2, and JR-1) and performed at Univerity of South Florida's Center for Geochemical Analyses. The analytical errors for major elements was smaller than 5 %, while for selected trace elements the error was usually smaller than 3 %. The same set of elements was measured on the same samples at University of South Florida's Anthropology Department using a pXRF device equipped with obsidian filter. Each sample was measured three times and the values were averaged. Two certified reference materials (NIST-612
Definitive Mineralogical Analysis of Mars Analog Rocks Using the CheMin XRD/XRF Instrument
NASA Technical Reports Server (NTRS)
Blake, D. F.; Sarrazin, P.; Bish, D. L.; Feldman, S.; Chipera, S. J.; Vaniman, D. T.; Collins, S.
2004-01-01
Mineral identification is a critical component of Mars Astrobiological missions. Chemical or elemental data alone are not definitive because a single elemental or chemical composition or even a single bonding type can represent a range of substances or mineral assemblages. Minerals are defined as unique structural and compositional phases that occur naturally. There are about 15,000 minerals that have been described on Earth, all uniquely identifiable via diffraction methods. There are likely many minerals yet undiscovered on Earth, and likewise on Mars. If an unknown phase is identified on Mars, it can be fully characterized by structural (X-ray Diffraction, XRD) and elemental analysis (X-ray Fluorescence, XRF) without recourse to other data because XRD relies on the principles of atomic arrangement for its determinations. XRD is the principal means of identification and characterization of minerals on Earth.
Full Field X-Ray Fluorescence Imaging Using Micro Pore Optics for Planetary Surface Exploration
NASA Technical Reports Server (NTRS)
Sarrazin, P.; Blake, D. F.; Gailhanou, M.; Walter, P.; Schyns, E.; Marchis, F.; Thompson, K.; Bristow, T.
2016-01-01
Many planetary surface processes leave evidence as small features in the sub-millimetre scale. Current planetary X-ray fluorescence spectrometers lack the spatial resolution to analyse such small features as they only provide global analyses of areas greater than 100 mm(exp 2). A micro-XRF spectrometer will be deployed on the NASA Mars 2020 rover to analyse spots as small as 120m. When using its line-scanning capacity combined to perpendicular scanning by the rover arm, elemental maps can be generated. We present a new instrument that provides full-field XRF imaging, alleviating the need for precise positioning and scanning mechanisms. The Mapping X-ray Fluorescence Spectrometer - "Map-X" - will allow elemental imaging with approximately 100µm spatial resolution and simultaneously provide elemental chemistry at the scale where many relict physical, chemical and biological features can be imaged in ancient rocks. The arm-mounted Map-X instrument is placed directly on the surface of an object and held in a fixed position during measurements. A 25x25 mm(exp 2) surface area is uniformly illuminated with X-rays or alpha-particles and gamma-rays. A novel Micro Pore Optic focusses a fraction of the emitted X-ray fluorescence onto a CCD operated at a few frames per second. On board processing allows measuring the energy and coordinates of each X-ray photon collected. Large sets of frames are reduced into 2d histograms used to compute higher level data products such as elemental maps and XRF spectra from selected regions of interest. XRF spectra are processed on the ground to further determine quantitative elemental compositions. The instrument development will be presented with an emphasis on the characterization and modelling of the X-ray focussing Micro Pore Optic. An outlook on possible alternative XRF imaging applications will be discussed.
Toward endoscopes with no distal optics: video-rate scanning microscopy through a fiber bundle.
Andresen, Esben Ravn; Bouwmans, Géraud; Monneret, Serge; Rigneault, Hervé
2013-03-01
We report a step toward scanning endomicroscopy without distal optics. The focusing of the beam at the distal end of a fiber bundle is achieved by imposing a parabolic phase profile across the exit face with the aid of a spatial light modulator. We achieve video-rate images by galvanometric scanning of the phase tilt at the proximal end. The approach is made possible by the bundle, designed to have very low coupling between cores.
Opportunities and Challenges of Linking Scientific Core Samples to the Geoscience Data Ecosystem
NASA Astrophysics Data System (ADS)
Noren, A. J.
2016-12-01
Core samples generated in scientific drilling and coring are critical for the advancement of the Earth Sciences. The scientific themes enabled by analysis of these samples are diverse, and include plate tectonics, ocean circulation, Earth-life system interactions (paleoclimate, paleobiology, paleoanthropology), Critical Zone processes, geothermal systems, deep biosphere, and many others, and substantial resources are invested in their collection and analysis. Linking core samples to researchers, datasets, publications, and funding agencies through registration of globally unique identifiers such as International Geo Sample Numbers (IGSNs) offers great potential for advancing several frontiers. These include maximizing sample discoverability, access, reuse, and return on investment; a means for credit to researchers; and documentation of project outputs to funding agencies. Thousands of kilometers of core samples and billions of derivative subsamples have been generated through thousands of investigators' projects, yet the vast majority of these samples are curated at only a small number of facilities. These numbers, combined with the substantial similarity in sample types, make core samples a compelling target for IGSN implementation. However, differences between core sample communities and other geoscience disciplines continue to create barriers to implementation. Core samples involve parent-child relationships spanning 8 or more generations, an exponential increase in sample numbers between levels in the hierarchy, concepts related to depth/position in the sample, requirements for associating data derived from core scanning and lithologic description with data derived from subsample analysis, and publications based on tens of thousands of co-registered scan data points and thousands of analyses of subsamples. These characteristics require specialized resources for accurate and consistent assignment of IGSNs, and a community of practice to establish norms
NASA Astrophysics Data System (ADS)
Boush, L. E.; Fentress, S.; Conroy, M.; Cook, A.; Miseridina, D.; Buynevich, I. V.; Myrbo, A.; Brown, E. T.; Berman, M.; Gnivecki, P.; Kjellmark, E.; Savarese, M.; Brady, K.
2013-12-01
Shad Pond, an enclosed hypersaline lagoon on the southeastern tip of Eleuthera, Bahamas reveals a ~5000-year record of hurricane activity, as well as sea-level and climate change history. Three sediment cores recovered 1.04-2.54 m of sediment over bedrock along a transect perpendicular to shoreline. Sediment composition and grain size, loss on ignition, X-ray fluorescence (XRF) measurements of the cores along with dune transects and ground-penetrating radar (GPR) profiles adjacent to the lake provide a comprehensive dataset to interpret the history of this coastal basin. The sedimentary sequence was composed of alternating lithofacies that included microbial mats, sand, and peat. Laminated mats often alternated with sandy layers in thin to medium-bedded units. Two peat layers were found in the basal part of the shore-distal core (Site 1) between 1.82-2.40 m and 2.53-2.54 m and were separated by a 13-cm-thick gray mud layer. In general, organic matter and carbonate content tracked granulometry and composition in all cores. High-resolution XRF scans of Ca and Sr at Site 1 show elevated levels ~3,700 cal yBP, which correlate with the top of the peat layer, but these elemental concentrations vary at Site 3. XRF measurements of Fe indicate a dust flux that has been recorded regionally throughout the Caribbean. Dune transects and GPR profiles indicate a phased history of the pond, beginning with initial stages as an open lagoon dominated by red mangrove, with black mangrove and buttonwood also present. The lake likely closed at approximately 3,700 cal yBP indicated by the transition between the upper peat and microbial mat layers. This could have been due to increased storm events in a regime of rising sea level. Aeolian aggradation continued to heighten the barrier between the bedrock headlands to its present position. Hurricane overwash deposits punctuated the algal mat accumulation throughout this time period. Present-day hypersaline conditions sustain algal mats
Lithography-Free Fabrication of Core-Shell GaAs Nanowire Tunnel Diodes.
Darbandi, A; Kavanagh, K L; Watkins, S P
2015-08-12
GaAs core-shell p-n junction tunnel diodes were demonstrated by combining vapor-liquid-solid growth with gallium oxide deposition by atomic layer deposition for electrical isolation. The characterization of an ensemble of core-shell structures was enabled by the use of a tungsten probe in a scanning electron microscope without the need for lithographic processing. Radial tunneling transport was observed, exhibiting negative differential resistance behavior with peak-to-valley current ratios of up to 3.1. Peak current densities of up to 2.1 kA/cm(2) point the way to applications in core-shell photovoltaics and tunnel field effect transistors.
NASA Astrophysics Data System (ADS)
He, X.; Li, H.; Wang, H.; Zhang, L., Jr.; Chevalier, M. L.
2016-12-01
The Anxian-Guanxian Fault (AGF) is a frontal fault of the Longmen Shan thrust belt, which ruptured during the 2008 Mw 7.9 Wenchuan earthquake in the eastern margin of the Tibetan Plateau. This study focuses on the 551.54 m-depth cores from the shallow hole of the Wenchuan earthquake Fault Scientific Drilling Project WFSD-3P which drilled across the AGF. Detailed core petrological study, geophysical downhole logs, rock magnetism and XRF analyses were conducted to explore the physical and chemical properties of the AGF, which is helpful to reveal the faulting mechanism and provides a reference to determine behaviors of other faults. The AGF zone in the WFSD-3p mainly consists of fault gouge and fault breccia from 442.41-510.14 m depth cores ( 48 m thick), with a dip angle of 45°. Fine-grained fault gouge and pressolution structures are commonly observed under optical microscope, which indicate the AGF is in creeping. The average magnetic susceptibility value of the fault gouge is slightly less than that of the country rock and the main magnetic carriers are pyrrhotite on the basis of low-temperature magnetic measurement. This phenomenon is different from the characteristics of other seismic faults with high magnetic susceptibility value due to heating by rapid slip friction. In terms of chemical properties, the fault gouge is characterized by relatively low concentration of iron, manganese and calcium, as well as high concentration of copper, vanadium and sulfur according to XRF analyses. In addition, the fluid samples are reductive, with a PH value of 10 and a negative value for redox potential. Combined with the grey-green sandstone along the rupture zone, they indicate that the AGF creeping is in a reducing environment. There are partly locked areas with clasts by rapid slip during the earthquake in the AGF zone. This observation was present at the boundary of the Triassic and Jurassic units ( 507 m depth), near the bottom of the fault zone. It represents the
NASA Astrophysics Data System (ADS)
Maruthi, Y. A.; Das, N. Lakshmana; Ramprasad, S.; Ram, S. S.; Sudarshan, M.
2015-08-01
The present studies focus the quantitative analysis of elements in school chalk to ensure the safety of its use. The elements like Calcium (Ca), Aluminum (Al), Iron (Fe), Silicon (Si) and Chromium (Cr) were analyzed from settled chalk dust samples collected from five classrooms (CD-1) and also from another set of unused chalk samples collected from local market (CD-2) using Energy Dispersive X-Ray florescence(ED-XRF) spectroscopy. Presence of these elements in significant concentrations in school chalk confirmed that, it is an irritant and occupational hazard. It is suggested to use protective equipments like filtered mask for mouth, nose and chalk holders. This study also suggested using the advanced mode of techniques like Digital boards, marker boards and power point presentations to mitigate the occupational hazard for classroom chalk
Li, Chen; Yu, Deng-Guang; Williams, Gareth R.; Wang, Zhuan-Hua
2014-01-01
This study reports on novel fast-dissolving core-shell composite microparticles of quercetin fabricated using coaxial electrospraying. A PVC-coated concentric spinneret was developed to conduct the electrospray process. A series of analyses were undertaken to characterize the resultant particles in terms of their morphology, the physical form of their components, and their functional performance. Scanning and transmission electron microscopies revealed that the microparticles had spherical morphologies with clear core-shell structure visible. Differential scanning calorimetry and X-ray diffraction verified that the quercetin active ingredient in the core and sucralose and sodium dodecyl sulfate (SDS) excipients in the shell existed in the amorphous state. This is believed to be a result of second-order interactions between the components; these could be observed by Fourier transform infrared spectroscopy. In vitro dissolution and permeation studies showed that the microparticles rapidly released the incorporated quercetin within one minute, and had permeation rates across the sublingual mucosa around 10 times faster than raw quercetin. PMID:24643072
In vivo evaluation of Fe in human skin employing X-Ray Fluorescence Methodology (XRF)
DOE Office of Scientific and Technical Information (OSTI.GOV)
Estevam, M.; Appoloni, C. R.
2007-02-12
Recent technological improvements allow the method of in vivo XRF to provide useful sensibility for diagnostics or monitoring in biomedical applications. In cases of hereditary sanguine disorders as the {beta}-thalassaemia or a genetic disorder like Haemochromatosis, there is a high concentration of elements as Fe, Zn and Cu in the skin and internal organs, due to the treatment of those abnormalities or due to the own dysfunction caused by the disease. The levels of Fe related to the patient bearers of the {beta}-thalassaemia are determined, at the moment, measuring a protein in the sanguine current, called ferritin. The monitoring ofmore » the protein is ineffective in several situations, such as when the patient suffers any disturbance of health. Nowadays, the main forms of measuring the levels of those metals through hepatic storage are the biopsy of the liver, that is invasive and potentially dangerous, presenting a rate of mortality of 0.1%, and by means of magnetic susceptibilities that employs a quantum superconductor, which is highly expensive and there are only three main world centers with this equipment This work investigates the use of a Si PIN-diode detector and a 238Pu source (13 and 17keV; 13%; 95.2mCi; 86y) for the measurement of Fe skin levels compatible with those associated to the disease {beta}-thalassaemia. XRF spectra were analyzed using a set of AXIL-WinQXAS programs elaborated and disseminated by the IAEA. The determination coefficient of the calibration model (sensitivity curve) was 0.97. Measurements on skin phantoms containing concentrations of Fe in the range from 10 to 150 parts per million (ppm), indicate that we are able to detect Fe at levels of the order of 15ppm, using monitoring periods of 50 seconds and skin entrance dose less than 10 mSv, The literature reports skin Fe levels from 15.0 to 60.0 ppm in normal persons and from 70 to 150 ppm in thalassaemics patients. So, the employed methodology allows the measurement of the skin
Gao, Weichun; Zhang, Yongxiang; Zhang, Xiaoye; Duan, Zhilong; Wang, Youhao; Qin, Can; Hu, Xiao; Wang, Hao; Chang, Shan
2015-11-01
In this study, coarse sand-supported zero valent iron (ZVI) composite was synthesized by adding sodium alginate to immobilize. Composite was detected by scanning electron microscope (SEM), X-ray diffraction (XRD), and X-ray fluorescence (XRF). SEM results showed that composite had core-shell structure and a wide porous distribution pattern. The synthesized composite was used for degradation of 2,4-dichlorophenol (2,4-DCP) contamination in groundwater. Experimental results demonstrated that degradation mechanism of 2,4-DCP using coarse sand-supported ZVI included adsorption, desorption, and dechlorination. 2,4-DCP adsorption was described as pseudo-second-order kinetic model. It was concluded that dechlorination was the key reaction pathway, ZVI and hydrogen are prime reductants in dechlorination of 2,4-DCP using ZVI.
Dynamic scan control in STEM: Spiral scans
Lupini, Andrew R.; Borisevich, Albina Y.; Kalinin, Sergei V.; ...
2016-06-13
Here, scanning transmission electron microscopy (STEM) has emerged as one of the foremost techniques to analyze materials at atomic resolution. However, two practical difficulties inherent to STEM imaging are: radiation damage imparted by the electron beam, which can potentially damage or otherwise modify the specimen and slow-scan image acquisition, which limits the ability to capture dynamic changes at high temporal resolution. Furthermore, due in part to scan flyback corrections, typical raster scan methods result in an uneven distribution of dose across the scanned area. A method to allow extremely fast scanning with a uniform residence time would enable imaging atmore » low electron doses, ameliorating radiation damage and at the same time permitting image acquisition at higher frame-rates while maintaining atomic resolution. The practical complication is that rastering the STEM probe at higher speeds causes significant image distortions. Non-square scan patterns provide a solution to this dilemma and can be tailored for low dose imaging conditions. Here, we develop a method for imaging with alternative scan patterns and investigate their performance at very high scan speeds. A general analysis for spiral scanning is presented here for the following spiral scan functions: Archimedean, Fermat, and constant linear velocity spirals, which were tested for STEM imaging. The quality of spiral scan STEM images is generally comparable with STEM images from conventional raster scans, and the dose uniformity can be improved.« less
Dynamic scan control in STEM: Spiral scans
DOE Office of Scientific and Technical Information (OSTI.GOV)
Lupini, Andrew R.; Borisevich, Albina Y.; Kalinin, Sergei V.
Here, scanning transmission electron microscopy (STEM) has emerged as one of the foremost techniques to analyze materials at atomic resolution. However, two practical difficulties inherent to STEM imaging are: radiation damage imparted by the electron beam, which can potentially damage or otherwise modify the specimen and slow-scan image acquisition, which limits the ability to capture dynamic changes at high temporal resolution. Furthermore, due in part to scan flyback corrections, typical raster scan methods result in an uneven distribution of dose across the scanned area. A method to allow extremely fast scanning with a uniform residence time would enable imaging atmore » low electron doses, ameliorating radiation damage and at the same time permitting image acquisition at higher frame-rates while maintaining atomic resolution. The practical complication is that rastering the STEM probe at higher speeds causes significant image distortions. Non-square scan patterns provide a solution to this dilemma and can be tailored for low dose imaging conditions. Here, we develop a method for imaging with alternative scan patterns and investigate their performance at very high scan speeds. A general analysis for spiral scanning is presented here for the following spiral scan functions: Archimedean, Fermat, and constant linear velocity spirals, which were tested for STEM imaging. The quality of spiral scan STEM images is generally comparable with STEM images from conventional raster scans, and the dose uniformity can be improved.« less
Studies on bronze pre-monetary signs found in Dobroudja using XRF and micro-PIXE
NASA Astrophysics Data System (ADS)
Constantinescu, B.; Cristea-Stan, D.; Talmatchi, G.; Ceccato, D.
2016-03-01
We performed compositional analyses on 180 Scythian-type arrowheads and pre-monetary signs using XRF method and on 60 small fragments of such items (approx. 100 microns diameter), sampling being performed on previously corrosion-cleaned areas on their surface, using micro-PIXE. The items are found in Dobroudja, Istros-Histria region. The most relevant for numismatists result is that for each finding place the same type of alloy was used both for fighting arrowheads and for pre-monetary signs. Our analyses revealed three types of alloys: Cu-Sn-Pb ("normal" bronze), Cu-Sn-Mn-Pb and Cu-Sn-Sb-Pb. The presence of antimony suggests the use of fahlore-type poly-metals deposits, most probably from Caucasus Mountains. The problem of ancient bronze containing manganese is more complicated; an explanation could be the use of manganese oxides as flux necessary to smelt oxidized ores.
MRI Evaluation of Post Core Decompression Changes in Avascular Necrosis of Hip.
Nori, Madhavi; Marupaka, Sravan Kumar; Alluri, Swathi; Md, Naseeruddin; Irfan, Kazi Amir; Jampala, Venkateshwarlu; Apsingi, Sunil; Eachempati, Krishna Kiran
2015-12-01
Avascular necrosis of hip typically presents in young patients. Core decompression in precollapse stage provides pain relief and preservation of femoral head. The results of core decompression vary considerably despite early diagnosis. The role of MRI in monitoring patients post surgically has not been clearly defined. To study pre and post core decompression MRI changes in avascular necrosis of hip. This is a contiguous observational cohort of 40 hips treated by core decompression for precollapse avascular necrosis of femoral head, who had a baseline MRI performed before surgery. Core decompression of the femoral head was performed within 4 weeks. Follow up radiograph and MRI scans were done at six months. Harris hip score preoperatively, 1 month and 6 months after the surgery was noted. Success in this study was defined as postoperative increase in Harris hip score (HHS) by 20 points and no additional femoral collapse. End point of clinical adverse outcome as defined by fall in Harris hip score was conversion or intention to convert to total hip replacement (THR). MRI parameters in the follow up scan were compared to the preoperative MRI. Effect of core decompression on bone marrow oedema and femoral head collapse was noted. Results were analysed using SPSS software version. Harris hip score improved from 57 to 80 in all patients initially. Six hips had a fall in Harris hip score to mean value of 34.1 during follow up (9 to 12 months) and underwent total hip replacement. MRI predictors of positive outcome are lesions with grade A extent, Grade A & B location. Bone marrow oedema with lesions less than 50% involvement, medial and central location. Careful selection of patients by MR criteria for core decompression provides satisfactory outcome in precollapse stage of avascular necrosis of hip.
MRI Evaluation of Post Core Decompression Changes in Avascular Necrosis of Hip
Marupaka, Sravan Kumar; Alluri, Swathi; MD, Naseeruddin; Irfan, Kazi Amir; Jampala, Venkateshwarlu; Apsingi, Sunil; Eachempati, Krishna Kiran
2015-01-01
Introduction Avascular necrosis of hip typically presents in young patients. Core decompression in precollapse stage provides pain relief and preservation of femoral head. The results of core decompression vary considerably despite early diagnosis. The role of MRI in monitoring patients post surgically has not been clearly defined. Aim To study pre and post core decompression MRI changes in avascular necrosis of hip. Materials and Methods This is a contiguous observational cohort of 40 hips treated by core decompression for precollapse avascular necrosis of femoral head, who had a baseline MRI performed before surgery. Core decompression of the femoral head was performed within 4 weeks. Follow up radiograph and MRI scans were done at six months. Harris hip score preoperatively, 1 month and 6 months after the surgery was noted. Success in this study was defined as postoperative increase in Harris hip score (HHS) by 20 points and no additional femoral collapse. End point of clinical adverse outcome as defined by fall in Harris hip score was conversion or intention to convert to total hip replacement (THR). MRI parameters in the follow up scan were compared to the preoperative MRI. Effect of core decompression on bone marrow oedema and femoral head collapse was noted. Results were analysed using SPSS software version. Results Harris hip score improved from 57 to 80 in all patients initially. Six hips had a fall in Harris hip score to mean value of 34.1 during follow up (9 to 12 months) and underwent total hip replacement. MRI predictors of positive outcome are lesions with grade A extent, Grade A & B location. Bone marrow oedema with lesions less than 50% involvement, medial and central location. Conclusion Careful selection of patients by MR criteria for core decompression provides satisfactory outcome in precollapse stage of avascular necrosis of hip. PMID:26816966
Aricò, Antonino S; Stassi, Alessandro; D'Urso, Claudia; Sebastián, David; Baglio, Vincenzo
2014-08-18
A composite Pd-based electrocatalyst consisting of a surface layer of Pt (5 wt.%) supported on a core Pd3Co1 alloy (95 wt.%) and dispersed as nanoparticles on a carbon black support (50 wt.% metal content) was prepared by using a sulphite-complex route. The structure, composition, morphology, and surface properties of the catalyst were investigated by XRD, XRF, TEM, XPS and low-energy ion scattering spectroscopy (LE-ISS). The catalyst showed an enrichment of Pt on the surface and a smaller content of Co in the outermost layers. These characteristics allow a decrease the Pt content in direct methanol fuel cell cathode electrodes (from 1 to 0.06 mg cm(-2)) without significant decay in performance, due also to a better tolerance to methanol permeated through the polymer electrolyte membrane. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Northern Cascadia Subduction Zone Earthquake Records from Onshore and Offshore Core Data
NASA Astrophysics Data System (ADS)
Hausmann, R. B.; Goldfinger, C.; Black, B.; Romsos, C. G.; Galer, S.; Collins, T.
2016-12-01
We are investigating the paleoseismic record at Bull Run Lake, at the latitude of Portland, Oregon, central Cascadia margin. Bull Run is a landslide dammed lake in a cirque basin on the western flanks of Mt. Hood, 65 km east of Portland, and is the City of Portland's primary water supply. We collected full coverage high-resolution multibeam and backscatter data, high resolution CHIRP sub-bottom profiles, and seven sediment cores which contain a correlative turbidite sequence of post Mazama beds. The continuity of the turbidite record shows little or no relationship to the minor stream inlets, suggesting the disturbance beds are not likely to be storm related. CT and physical property data were used to separate major visible beds and background sedimentation, which also contain thin laminae. The XRF element Compton scattering may show grading due to mineralogical variation and a change in wave profile, commonly found at bed boundaries. We have identified 27 post -Mazama event beds and 5 ashes in the lake, and constructed an OxCal age model anchored by radiocarbon ages, the Mazama ash, and the twin Timberline ash beds. The radiocarbon ages, age model results, as well as electron microprobe (EMP) data clearly identify the Mazama ash at the base of our cores. Two closely-spaced ash beds in our cores likely correlate to the Timberline eruptive period at 1.5ka. The number, timing and sequence of the event beds, and physical property log correlation, as well as key bed characteristics, closely matches offshore turbidite sequences off northern Oregon. For example, key regional bed T11, observed as a thick two-pulse bed in all offshore cores, also anchors the Bull Run sequence. One difference is that the twin Timberline ash occupies the stratigraphic position of regional offshore paleoseismic bed T4, which is also a two pulse event at this latitude. The cores also contain many faint laminae that may contain a storm record, however, the identification of small beds is
2001-10-15
by Friedman outside the field of XRF is available within the holdings of the NRL Ruth H. Hooker Research Library and Technical Information Center...Herbert Friedman. The extensive collection of publications by Friedman outside the field of XRF is available within the holdings of the NRL Ruth H. Hooker...and which includes other information and filenames of electronic scans of many of the entries) has been supplied to the NRL Ruth H. Hooker Research
Electrosprayed core-shell polymer-lipid nanoparticles for active component delivery
NASA Astrophysics Data System (ADS)
Eltayeb, Megdi; Stride, Eleanor; Edirisinghe, Mohan
2013-11-01
A key challenge in the production of multicomponent nanoparticles for healthcare applications is obtaining reproducible monodisperse nanoparticles with the minimum number of preparation steps. This paper focus on the use of electrohydrodynamic (EHD) techniques to produce core-shell polymer-lipid structures with a narrow size distribution in a single step process. These nanoparticles are composed of a hydrophilic core for active component encapsulation and a lipid shell. It was found that core-shell nanoparticles with a tunable size range between 30 and 90 nm and a narrow size distribution could be reproducibly manufactured. The results indicate that the lipid component (stearic acid) stabilizes the nanoparticles against collapse and aggregation and improves entrapment of active components, in this case vanillin, ethylmaltol and maltol. The overall structure of the nanoparticles produced was examined by multiple methods, including transmission electron microscopy and differential scanning calorimetry, to confirm that they were of core-shell form.
Corrugated metal-coated tapered tip for scanning near-field optical microscope.
Antosiewicz, Tomasz J; Szoplik, Tomasz
2007-08-20
This paper addresses an important issue of light throughput of a metal-coated tapered tip for scanning near-field microscope (SNOM). Corrugations of the interface between the fiber core and metal coating in the form of parallel grooves of different profiles etched in the core considerably increase the energy throughput. In 2D FDTD simulations in the Cartesian coordinates we calculate near-field light emitted from such tips. For a certain wavelength range total intensity of forward emission from the corrugated tip is 10 times stronger than that from a classical tapered tip. When realized in practice the idea of corrugated tip may lead up to twice better resolution of SNOM.
Nayak, P; Behera, P R; Thirunavoukkarasu, M; Chand, P K
2011-03-01
The Energy Dispersive X-ray Fluorescence (ED-XRF) set-up incorporating a molybdenum secondary exciter was used for quantitative determination of major and minor elements in leaves of in vivo grown medicinal herb Phyllanthus amarus vis-á-vis its leaf-derived in vitro callus culture. The elements such as K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, Rb, Sr and Pb were identified, quantified and compared between both the sources. Experimental results revealed that, compared to the naturally grown herb, in vitro leaf-derived callus cultures were more efficient in accumulating inorganic elements, especially trace elements, which are essential for growth and development and more importantly for prevention and cure of diseases. This investigation on a medicinal plant species is the first of its kind to have used the ED-XRF technique to demonstrate a comparative account of the elemental profile of in vitro callus cultures with their in vivo donor in order to explore the possibility of exploiting the former as a viable alternative and a renewable source of phytochemicals. Copyright © 2010 Elsevier Ltd. All rights reserved.
Analysis of sculptures using XRF and X-ray radiography
NASA Astrophysics Data System (ADS)
Calza, C.; Oliveira, D. F.; Freitas, R. P.; Rocha, H. S.; Nascimento, J. R.; Lopes, R. T.
2015-11-01
This work reports the analysis of two sacred images on polychrome wood using X-ray Radiography and Energy Dispersive X-Ray Fluorescence. The first case is the analysis of a sculpture portraying Saint Sebastian, the patron saint of Rio de Janeiro, which is considered the second most ancient sacred image of Brazil. This sculpture was made in Portugal and was transported to Brazil by Estácio Sá, founder of the city of Rio de Janeiro, in 1565. Nowadays, it is located on the main altar of the Church of Capuchin Friars. The second case is the analysis of a sculpture representing Our Lady of Conception, which is located in the D. João VI Museum (EBA/UFRJ, Rio de Janeiro). The objective of these analyses was to evaluate the general conditions of the sculptures, identifying possible problems and internal damages, areas that revealed signs of previous retouchings and the materials and pigments employed by the artists, in order to assist its restoration procedures. EDXRF measurements were carried out with a portable system, developed at the Nuclear Instrumentation Laboratory, consisting of a Si-PIN XR-100CR detector from Amptek and an Oxford TF3005 X-ray tube with W anode. An X-ray source, a CR System GE CR50P and IP detectors were used to perform the radiographs. The XRF analysis of the sculptures identified the original pigments in both cases and the radiographic images revealed details of the manufacture; restored regions; extensive use of lead white; presence of cracks on the wood; use of nails and spikes, etc.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Maruthi, Y. A., E-mail: ymjournal2014@gmail.com; Das, N. Lakshmana, E-mail: nldas9@gmail.com; Ramprasad, S., E-mail: ramprasadsurakala@gmail.com
The present studies focus the quantitative analysis of elements in school chalk to ensure the safety of its use. The elements like Calcium (Ca), Aluminum (Al), Iron (Fe), Silicon (Si) and Chromium (Cr) were analyzed from settled chalk dust samples collected from five classrooms (CD-1) and also from another set of unused chalk samples collected from local market (CD-2) using Energy Dispersive X-Ray florescence(ED-XRF) spectroscopy. Presence of these elements in significant concentrations in school chalk confirmed that, it is an irritant and occupational hazard. It is suggested to use protective equipments like filtered mask for mouth, nose and chalk holders.more » This study also suggested using the advanced mode of techniques like Digital boards, marker boards and power point presentations to mitigate the occupational hazard for classroom chalk.« less
NASA Astrophysics Data System (ADS)
Shakhreet, B. Z.; Bauk, S.; Shukri, A.
2015-02-01
Compton (incoherently) scattered photons which are directly proportional to the electron density of the scatterer, have been employed in characterizing Rhizophora spp. as breast tissue equivalent. X-ray fluorescent scattered incoherently from Rhizophora spp. sample was measured using Si-PIN detector and three XRF energy values 15.77, 17.48 and 22.16 keV. This study is aimed at providing electron density information in support of the introduction of new tissue substitute materials for mammography phantoms.
NASA Astrophysics Data System (ADS)
Roethe, T.; Bakke, J.; Støren, E.
2016-12-01
Here we present work in progress from Buarvatnet at the Folgefonn Peninsula, located on the west coast of Norway. Earlier work from Buarvatnet indicated several distinct spikes in the Silica count rates, detected by the ITRAX surface XRF-scanner. However, the process behind these distinct spikes was not understood. The arrival of high-resolution and innovative instruments at EARTHLAB, in particular the computed tomography (CT) scanner and grain Morphometer, have the potential to get a process-based understanding of these distinct layers and unravel the frequency and timing of such events. Multiple sediment cores were retrieved using a modified piston corer and a Uwitech corer from Buarvatnet. The sediments have been analysed using a multi-proxy approach and the analyses included magnetic properties, loss-on-ignition, dry bulk density, grain size/shape, geochemical analysis (XRF scanning) and CT-scanning. Accurate age-control will be achieved through 210Pb dating of the top-most sediments and 14C dating of terrestrial macrofossils. The lithostratigraphy of the 3.6 m long master sediment core from Buarvatnet is divided into three distinct units. The lower most unit ( 87 cm) is massive with fine-grained greyish sediments, most likely representing the deglaciation of the area. A 224 cm long unit is found above, characterised as dark brown gyttja with multiple thin layers (sub-mm to cm thick) of fine grained sediments. Also in this unit is two distinct sub-units showing a finer upwards sequence. At top, a gradual transition from dark brown gyttja to grey fine-grained sediments is found in the upper-most 19 cm of the sediment core. In total 16 distinct layers is found in the gyttja sequence, including the two sub-units, based on the lithostratigraphy and the prelimnary results from the magnetic, physical and geochemical properties. A preliminary hypothesis is that these distinct layers are due to outburst floods from a glacier-dammed lake upstream from Buarvatnet. In
Lacustrine records of Holocene climate and environmental change from the Lofoten Islands, Norway
NASA Astrophysics Data System (ADS)
Balascio, Nicholas L.
lake was isolated and defines sea-level regression following the Tapes transgression. Cryptotephra horizons were identified in sediments of Heimerdalsvatnet, Vikjordvatnet, and Sverigedalsvatn. They were also found in a Viking-age boathouse excavated along the shore of Inner Borgpollen. These include the GA4-85, BIP-24a, SILK-N2, Askja, 860 Layer B, Hekla 1158, Hekla 1104, Vedde Ash, and Saksunarvatn tephra. This research project also explored the use of scanning XRF to locate cryptotephra in lacustrine sediments and presents experimental results of XRF scans of tephra-spiked synthetic sediment cores.
Room-temperature ferromagnetic Cr-doped Ge/GeOx core-shell nanowires.
Katkar, Amar S; Gupta, Shobhnath P; Seikh, Md Motin; Chen, Lih-Juann; Walke, Pravin S
2018-06-08
The Cr-doped tunable thickness core-shell Ge/GeO x nanowires (NWs) were synthesized and characterized using x-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, energy-dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy and magnetization studies. The shell thickness increases with the increase in synthesis temperature. The presence of metallic Cr and Cr 3+ in core-shell structure was confirmed from XPS study. The magnetic property is highly sensitive to the core-shell thickness and intriguing room temperature ferromagnetism is realized only in core-shell NWs. The magnetization decreases with an increase in shell thickness and practically ceases to exist when there is no core. These NWs show remarkably high Curie temperature (T C > 300 K) with the dominating values of its magnetic remanence (M R ) and coercivity (H C ) compared to germanium dilute magnetic semiconductor nanomaterials. We believe that our finding on these Cr-doped Ge/GeO X core-shell NWs has the potential to be used as a hard magnet for future spintronic devices, owing to their higher characteristic values of ferromagnetic ordering.
[Three-dimensional computer aided design for individualized post-and-core restoration].
Gu, Xiao-yu; Wang, Ya-ping; Wang, Yong; Lü, Pei-jun
2009-10-01
To develop a method of three-dimensional computer aided design (CAD) of post-and-core restoration. Two plaster casts with extracted natural teeth were used in this study. The extracted teeth were prepared and scanned using tomography method to obtain three-dimensional digitalized models. According to the basic rules of post-and-core design, posts, cores and cavity surfaces of the teeth were designed using the tools for processing point clouds, curves and surfaces on the forward engineering software of Tanglong prosthodontic system. Then three-dimensional figures of the final restorations were corrected according to the configurations of anterior teeth, premolars and molars respectively. Computer aided design of 14 post-and-core restorations were finished, and good fitness between the restoration and the three-dimensional digital models were obtained. Appropriate retention forms and enough spaces for the full crown restorations can be obtained through this method. The CAD of three-dimensional figures of the post-and-core restorations can fulfill clinical requirements. Therefore they can be used in computer-aided manufacture (CAM) of post-and-core restorations.
NASA Astrophysics Data System (ADS)
Hošek, Michal; Matys Grygar, Tomáš; Popelka, Jan; Kiss, Timea; Elznicová, Jitka; Faměra, Martin
2017-04-01
In the recent years researchers have enjoyed noticeable improvements of portable analytical and geophysical methods, which allow studying floodplain architecture and deciphering pollutant distribution more easily than ever before. Our area of interest was floodplain of the Ploučnice River, particularly a pollution hotspot in Boreček, severely impacted by U mining between the 1970s and late 1980s, in particular a "radioactive flood" in 1981. In the area, we used hand drill coring and in situ (field) analysis of so acquired sediments by handheld X-ray fluorescence spectrometer (XRF), which gave us information about depth profiles of pollutants (Ba, U, Zn) and the Al/Si and Zr/Rb ratios, i.e., proxies for sediment lithology. We found that spatial distribution of pollutants (control by depth and position in the floodplain) is apparently complex and discontinuous. In some places, contamination is buried by a couple decimetres of less polluted sediments, while in other places the peak pollution is near surface, apparently without a straightforward connection with the surface topography and the distance to the river channel. We thus examined the floodplain architecture, the internal structure of the floodplain using two geophysical methods. First of them, dipole electromagnetic profiling (DEMP, also denoted EMP, MP, or Slingram) quickly acquires average electric resistivity in top strata in selected areas, which was actually top 3 m with our particular instrument. Second, electric resistivity tomography (ERT) produces much more detailed information on resistivity with depth resolution of ca 0.5 m to the depth of ca 5 m in selected lines. ERT thus allows identifying boundaries of electric resistivity domains (sediment bodies) and DEMP their spatial distribution. Based on the obtained data, we divided the floodplain to five segments with specific topography, pollution characteristics, and electric resistivity. We suppose that those segments are lithogenetic floodplain
DOE Office of Scientific and Technical Information (OSTI.GOV)
Kenneth Krebs, John Svoboda
2009-11-01
SCAN+ is a software application specifically designed to control the positioning of a gamma spectrometer by a two dimensional translation system above spent fuel bundles located in a sealed spent fuel cask. The gamma spectrometer collects gamma spectrum information for the purpose of spent fuel cask fuel loading verification. SCAN+ performs manual and automatic gamma spectrometer positioning functions as-well-as exercising control of the gamma spectrometer data acquisitioning functions. Cask configuration files are used to determine the positions of spent fuel bundles. Cask scanning files are used to determine the desired scan paths for scanning a spent fuel cask allowing formore » automatic unattended cask scanning that may take several hours.« less
Magnetic signatures of Heinrich-like detrital layers in the Quaternary of the North Atlantic
NASA Astrophysics Data System (ADS)
Channell, J. E. T.; Hodell, D. A.
2013-05-01
Magnetic parameters are useful for distinguishing North Atlantic Heinrich-like detrital layers from background sediments. Here we compare magnetic properties with XRF scanning data back to 700 ka and 1.3 Ma at IODP Sites U1302-U1303 and U1308, respectively. Multi-domain magnetite, with grain sizes >20 µm, is characteristic of both Ca- and Si-rich detrital layers, as defined by XRF core scanning, confirming the contribution of ice rafting. Reflectance spectra and magnetic parameters distinguish Ca- and Si-rich IRD layers due the presence of high coercivity hematite in Si-rich layers. Heinrich layer 6 (H6) at Site U1302-U1303 is unlike other detrital layers, being marked by a 45-cm thick homogeneous cream-colored clay layer underlain by a thin (5-cm) graded coarse-sand. Comparison of Site U1302/03 and Site U1308 detrital layers implies a dominant Laurentide source for both Ca- and Si-rich detrital layers. At Site U1308, low benthic δ13C values during stadials are in-step with magnetic grain-size coarsening associated with Si-rich detrital layers back to 1.3 Ma, indicating a link between deep-sea ventilation and ice rafting. The surface-sediment tan-colored oxic layer (~2 m thick at Site U1308) yields magnetic hysteresis ratios that are offset from the single-domain to multi-domain (SD-MD) magnetite mixing-line in hysteresis-ratio diagrams. This offset is attributed to maghemite grain-coatings, that form on magnetite in surface sediment, and undergo dissolution as they pass through the oxic/anoxic boundary.
NASA Astrophysics Data System (ADS)
Sato, Eiichi; Sato, Yuichi; Ehara, Shigeru; Abudurexiti, Abulajiang; Hagiwara, Osahiko; Matsukiyo, Hiroshi; Osawa, Akihiro; Enomoto, Toshiyuki; Watanabe, Manabu; Nagao, Jiro; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun
2011-05-01
X-ray fluorescence (XRF) analysis is useful for mapping various atoms in objects, and XRF is emitted by absorbing X-ray photons with energies beyond the K-edge energy of the target atom. Narrow-energy-width bremsstrahlung X-rays are selected using a 3.0-mm-thick aluminum filter. These rays are absorbed by iodine media in objects, and iodine XRF is produced from the iodine atoms. Next, iodine Kα photons are discriminated by a multichannel analyzer and the number of photons is counted by a counter card. CT is performed by repeated linear scans and rotations of an object. The X-ray generator has a 100 μm focus tube with a 0.5-mm-thick beryllium window, and the tube voltage and the current for XRF were 80 kV and 0.50 mA, respectively. The demonstration of XRF-CT for mapping iodine atoms was carried out by selection of photons in an energy range from 27.5 to 29.5 keV with a photon-energy resolution of 1.2 keV.
NASA Astrophysics Data System (ADS)
Olsen, P. E.; Geissman, J. W.; Gehrels, G. E.; Irmis, R. B.; Kent, D. V.; Mundil, R.; Parker, W.; Sha, J.; Molina-Garza, R. S.; Kuerschner, W.; Bachmann, G. H.; Schaller, M. F.; Zakharova, N. V.; Colbert, M.
2014-12-01
The Triassic Period (251.9-201.3 Ma) is bound by two of the Earth's largest mass extinctions, suffered several giant bolide impacts and eruption of 3 large igneous provinces, and witnessed evolution of the main components of modern tetrapod communities, and yet has sparse geochronological calibration. To bridge this gap, NSF- and ICDP-funded coring of Phase 1 of the CPCP finished in 12/2013 with the recovery of two major cores (1A, 518m and 2B, 253m; 31km apart) from opposites sides of Petrified Forest National Park spanning nearly the entire Triassic sequence (Chinle & Moenkopi fms) with many U-Pb datable levels (1,2,3) and a recoverable paleomagnetic polarity record (4). The cores will provide a U-Pb and paleomagnetic exportable time scale and sedimentary and geochemical proxies with undoubted superposition testing the motivating hypotheses of: 1) the accuracy of orbitally-paced cyclicity of the Newark APTS (5); 2) apparent climate trends as a function of drift through climate belts (6) and atmospheric CO2 (7); 3) the temporal link between the mid-Late Triassic biotic turnover and the ~100 km Manicouagan impact (1); and 4) the delayed ecological dominance of dinosaurs coupled to climate-driven provinciality (1,8). For orientation, the cores were drilled using a azimuth-tracking device, deviated 30° and 15° from vertical to the SE and S, and CT-scanned. The unprecedented sedimentological and stratigraphic detail visible in the CT-scans, and geophysical logs, plus the ~100% recovery promises successful tests of the motivating hypotheses and provide a superbly detailed reference section for this key episode in Earth system history. 1, Irmis+,2011, EPSL 309:258; 2, Ramazani+, 2011, GSA Bull. 123:2142; 3, Ramazani+, 2014, AJS 314:981; 4, Steiner & Lucas, 2000, JGR B 105:25791; 5, Kent & Olsen, 1999, JGR 104(B6):12831-12841; 6, Kent and Tauxe, 2005, Science 307:240-244; 7, Schaller+, 2012, EPSL 323-324:27-39; 8, Kent +, 2014, PNAS 111:7958-7963.
Neff, Hector; Bigney, Scott J; Sakai, Sachiko; Burger, Paul R; Garfin, Timothy; George, Richard G; Culleton, Brendan J; Kennett, Douglas J
2016-01-01
Archaeological sediments from mounds within the mangrove zone of far-southern Pacific coastal Chiapas, Mexico, are characterized in order to test the hypothesis that specialized pyro-technological activities of the region's prehistoric inhabitants (salt and ceramic production) created the accumulations visible today. Fourier transform infrared spectroscopy (FT-IR) is used to characterize sediment mineralogy, while portable X-ray fluorescence (pXRF) is used to determine elemental concentrations. Elemental characterization of natural sediments by both instrumental neutron activation analysis (INAA) and pXRF also contribute to understanding of processes that created the archaeological deposits. Radiocarbon dates combined with typological analysis of ceramics indicate that pyro-industrial activity in the mangrove zone peaked during the Late Formative and Terminal Formative periods, when population and monumental activity on the coastal plain and piedmont were also at their peaks. © The Author(s) 2015.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Lappin-Scott, H.M.; Cusack, F.; Costerton, J.W.
1988-06-01
Klebsiella pneumoniae, which was reduced in size (0.25 by 0.5 ..mu..m) by carbon deprivation, was injected into a series of sandstone cores and subjected to separate treatments. Scanning electron microscopy of 400-mD cores showed these small starved cells in nearly every core section. The cells were a mixture of small rods and cocci with little or no biofilm production. Continuous or dose stimulation with sodium citrate allowed the cells to grow throughout the sandstone and completely plug the length of the core. The resuscitated cells were larger than the starved cells (up to 1.7 ..mu..m) and were encased in glycocalyx.more » Scanning electron microscopic results of resuscitation in situ with half-strength brain heart infusion broth showed that a shallow skin plug of cells formed at the core inlet and that fewer cells were located in the lower sections. Starved cells also penetrated 200-mD cores and were successfully resuscitated in situ with sodium citrate, so that the entire core was plugged. Nutrient resuscitation of injected starved cells to produce full-size cells which grow and block the rock pores may be successfully applied to selective plugging and may effectively increase oil recovery.« less
The Alzheimer's Disease Neuroimaging Initiative 2 PET Core: 2015.
Jagust, William J; Landau, Susan M; Koeppe, Robert A; Reiman, Eric M; Chen, Kewei; Mathis, Chester A; Price, Julie C; Foster, Norman L; Wang, Angela Y
2015-07-01
This article reviews the work done in the Alzheimer's Disease Neuroimaging Initiative positron emission tomography (ADNI PET) core over the past 5 years, largely concerning techniques, methods, and results related to amyloid imaging in ADNI. The PET Core has used [(18)F]florbetapir routinely on ADNI participants, with over 1600 scans available for download. Four different laboratories are involved in data analysis, and have examined factors such as longitudinal florbetapir analysis, use of [(18)F]fluorodeoxyglucose (FDG)-PET in clinical trials, and relationships between different biomarkers and cognition. Converging evidence from the PET Core has indicated that cross-sectional and longitudinal florbetapir analyses require different reference regions. Studies have also examined the relationship between florbetapir data obtained immediately after injection, which reflects perfusion, and FDG-PET results. Finally, standardization has included the translation of florbetapir PET data to a centiloid scale. The PET Core has demonstrated a variety of methods for the standardization of biomarkers such as florbetapir PET in a multicenter setting. Copyright © 2015 The Alzheimer's Association. Published by Elsevier Inc. All rights reserved.
NASA Astrophysics Data System (ADS)
Sadat Mohajerani, Matin; Müller, Marcus; Hartmann, Jana; Zhou, Hao; Wehmann, Hergo-H.; Veit, Peter; Bertram, Frank; Christen, Jürgen; Waag, Andreas
2016-05-01
Three-dimensional (3D) InGaN/GaN quantum-well (QW) core-shell light emitting diodes (LEDs) are a promising candidate for the future solid state lighting. In this contribution, we study direct correlations of structural and optical properties of the core-shell LEDs using highly spatially-resolved cathodoluminescence spectroscopy (CL) in combination with scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM). Temperature-dependent resonant photoluminescence (PL) spectroscopy has been performed to understand recombination mechanisms and to estimate the internal quantum efficiency (IQE).
The Fast Evolution of SN 2010bh Associated with XRF 100316D
NASA Technical Reports Server (NTRS)
Olivares E., F.; Greiner, J.; Schady, P.; Rau, A.; Klose, S.; Kruhler, T.; Afonso, P. M. J.; Updike, A. C.; Nardini, M.; Filgas, R.;
2012-01-01
The first observational evidence of a connection between supernovae (SNe) and gamma-ray bursts (GRBs) was found about a decade ago. Since then, only half a dozen spectroscopically confirmed associations have been discovered and XRF 1003160 associated with the type-Ic SN 20lObh is among the latest. Aims. We constrain the progenitor radius, the host-galaxy extinction, and the physical parameters of the explosion of XRF l00316D/SN 20lObh at z 0.059. We study the SN brightness and colours in the context of GRB-SNe. Methods. We began observations with the Gamma-Ray burst Optical and Near-infrared Detector (GROND) 12 hours after the GRB trigger and continued until 80 days after the burst. GROND provided excellent photometric data in six filter bands covering a wavelength range from approximately 350 to 1800 nm, significantly expanding the pre-existing data set for this event. Combining GROND and Swift data, the early broad-band spectral energy distribution (SED) is modelled with a blackbody and afterglow component attenuated by dust and gas absorption. The temperature and radius evolution of the thermal component are analysed and combined with earlier measurements available from the literature. Templates of SN 1998bw are fitted to the SN itself to directly compare the lightcurve properties. Finally, a two-component parametrized model is fitted to the quasi-bolometric light curve. which delivers physical parameters of the explosion. Results. The best-fit models to the broad-band SEDs imply moderate reddening along the line of sight through the host galaxy (A(sub v.host = 1.2 +/- 0.1 mag). Furthermore, the parameters of the blackbody component reveal a cooling envelope at an apparent initial radius of 7 x 10(exp 11) cm, which is compatible with a dense wind surrounding a Wolf-Rayet star. A multicolor comparison shows that SN 2010bh is 60 - 70% as bright as SN 1998bw. Reaching maximum brightness at 8 - 9 days after the burst in the blue bands, SN 20lObh proves to be the
NASA Astrophysics Data System (ADS)
Wutke, Kristina; Wulf, Sabine; Tomlinson, Emma L.; Hardiman, Mark; Dulski, Peter; Luterbacher, Jürg; Brauer, Achim
2015-06-01
We present the results of new tephrostratigraphical and environmental impact studies of the 40-38 ka varved sediment section of Lago Grande di Monticchio (southern Italy). The sediments in this time zone are correlated with the Heinrich H4-stadial that occurred between Greenland Interstadials GI-9 and GI-8, and include the widespread Campanian Ignimbrite (CI, 39.3 ka) as a thick tephra layer in the middle of the H4 stadial. The CI in the Monticchio record is overlain by the Schiava tephra from Vesuvius, c. 1240 varve-years younger than the CI, and preceded by four tephras from small-scale eruptions of the Phlegrean Fields and by an Ischia-derived tephra. The four Phlegrean Field-derived tephras were deposited 600 varve-years or fewer prior to the deposition of the CI and show very similar major, minor, and trace element glass compositions to those of the CI. This close similarity in composition and age could compromise the accurate linking and synchronisation of palaeoenvironmental records in the central Mediterranean area. Microfacies analyses and μ-XRF core scanning were used to characterise primary and secondary depositional features of all seven tephra layers and to evaluate environmental and ecological responses after tephra deposition. Higher concentrations of tephra-derived material (mainly glass shards and pumices) in primary and reworked layers were detected by elevated K-counts in μ-XRF elemental core scans. Reworked tephra derives mainly from in-washing from the littoral zone and the catchment and occurs within five to 30 years, and up to 1240 varve years, after the deposition of thinner (1-5 mm) and thicker (5-230 mm) tephra fallout deposits, respectively. An obvious response of diatom population growth directly after the primary tephra deposition was observed for the thicker tephra layers (>1 mm) during the first 1-8 years after deposition of the primary deposit indicating that the additional input of potential nutrients (glass shards) temporarily
NASA Astrophysics Data System (ADS)
Wang, Yazhou; Zhang, Yiqiong; Wang, Bochu; Cao, Yang; Yu, Qingsong; Yin, Tieying
2013-06-01
The study aimed at constructing a novel drug delivery system for programmable multiple drug release controlled with core-shell structure. The core-shell structure consisted of chitosan nanoparticles as core and polyvinylpyrrolidone micro/nanocoating as shell to form core-shell micro/nanoparticles, which was fabricated by ionic gelation and emulsion electrospray methods. As model drug agents, Naproxen and rhodamine B were encapsulated in the core and shell regions, respectively. The core-shell micro/nanoparticles thus fabricated were characterized and confirmed by scanning electron microscope, transmission electron microscope, and fluorescence optical microscope. The core-shell micro/nanoparticles showed good release controllability through drug release experiment in vitro. It was noted that a programmable release pattern for dual drug agents was also achieved by adjusting their loading regions in the core-shell structures. The results indicate that emulsion electrospraying technology is a promising approach in fabrication of core-shell micro/nanoparticles for programmable dual drug release. Such a novel multi-drug delivery system has a potential application for the clinical treatment of cancer, tuberculosis, and tissue engineering.
PMMA/PS coaxial electrospinning: core-shell fiber morphology as a function of material parameters
NASA Astrophysics Data System (ADS)
Rahmani, Shahrzad; Arefazar, Ahmad; Latifi, Masoud
2017-03-01
Core-shell fibers of polymethyl methacrylate (PMMA) and polystyrene (PS) have been successfully electrospun by coaxial electrospinning. To evaluate the influence of the solvent on the final fiber morphology, four types of organic solvents were used in the shell solution while the core solvent was preserved. Morphological observations with scanning electron microscopy, transmission electron microscopy and optical microscopy revealed that both core and shell solvent properties were involved in the final fiber morphology. To explain this involvement, alongside a discussion of the Bagley solubility graph of PS and PMMA, a novel criterion based on solvent physical properties was introduced. A theoretical model based on the momentum conservation principle was developed and applied for describing the dependence of the core and shell diameters to their solvent combinations. Different concentrations of core and shell were also investigated in the coaxial electrospinning of PMMA/PS. The core-shell fiber morphologies with different core and shell concentrations were compared with their single electrospun fibers.
IRD evidence for Heinrich Events H1 and H2 on the NJ Margin
NASA Astrophysics Data System (ADS)
Christensen, B. A.; Calabrese, J.; O'Neill, C.; Goff, J. A.
2011-12-01
Recent seismic reflection studies suggest icebergs grounded on the late Pleistocene New Jersey margin (Goff and Austin, 2009) during Heinrich events H1 (~17 cal Ka), H2 (~23 cal Ka), H3 (~30 cal Ka) and H4 (~37 cal Ka). We tested this hypothesis by analyzing sediments on the upper NJ continental slope, near the area where icebergs were found. Ocean Drilling Program Site 1073A is located at 39°13.5214'N, 72°16.5461'W in 639 m water depth. The greater water depth increases the likelihood of preservation and improves the stratigraphic control. We obtained elemental measurements for Site 1073A Cores 1-6 using the X-ray Fluorescence (XRF) Core Scanner at the MARUM IODP core repository, University of Bremen. Cores were scanned at 10kV and 30kV to obtain a full suite of elements for analysis, with XRF data collected between 1 and 10 cm intervals. The values are reported in areas for the elements and were then converted to elemental ratios (Ca/Sr, Si/Sr, K/Al, and Si/Ti) for analysis. The origin of a Heinrich layer within an IRD belt can be identified by geochemical measures along with magnetic susceptibility and the presence of detrital materials that reflect its provenance (Hemming, 2004). Following analyses for Atlantic Ocean IRD by Hodell et al. (2008), higher Si/Sr values indicate abundant detrital silicates and low biogenic carbonate. Abundant detrital carbonate is identified by higher Ca/Sr values. K/Al may be used as a proxy for weathered matter being deposited and is a good indicator of terrigenous material (Yarincik, 2000). Si/Ti ratios may be used as a proxy for organic and siliceous productivity (Agnihotri, 2008). The elemental analysis was ground-truthed with grain size analysis at 10 cm intervals. Grain size analysis reveals large particles in a finer matrix at 123 cm and 284 cm. We interpret these as IRD. A linear sedimentation age model places the IRD around the time of Heinrich events H1 and H2. Age control is provided for the late Pleistocene
NASA Astrophysics Data System (ADS)
Francke, A.; Wagner, B.; Sulpizio, R.; Zanchetta, G.; Leicher, N.; Gromig, R.; Krastel, S.; Lindhorst, K.; Wilke, T.
2014-12-01
Ancient lakes, with sediment records spanning >1 million years, are very rare. The UNESCO World Heritage site of Lake Ohrid on the Balkans is thought to be the oldest lake in Europe. With 212 endemic species described to date, it is also a hotspot of evolution. In order to unravel the geological and evolutionary history of the lake, an international group of scientists, conducted a deep drilling campaign in spring 2013 under the umbrella of the ICDP SCOPSCO project (Scientific Collaboration on Past Speciation Conditions in Lake Ohrid). Overall, about 2,100 m of sediments were recovered from four drill sites. At the main drill site (DEEP-site) in central parts of the lake where seismic data indicated a maximum sediment fill of ca. 700 m, a total of more than 1,500 m of sediments were recovered until a penetration depth of 569 m. Currently, core opening, core description, XRF and MSCL scanning, sub-sampling (16 cm resolution), and inorganic and organic geochemical as well as sedimentological analyses of the sediment cores from the DEEP site are in progress at the University of Cologne. Previous studies at Lake Ohrid have shown that interglacial periods are characterized by high TIC and TOC contents, likely associated with high contents of calcite and organic matter in the sediments. In contrast, during glacial periods negligible TIC and low TOC contents correspond to high K counts indicating enhanced supply of clastic material. Similar patterns can be observed in the biogeochemical analyses of the subsamples and in the XRF data of the DEEP site record. Following these variations on a glacial-interglacial time scale, TIC and TOC data obtained from the subsamples and from core catcher samples indicate that the DEEP site sequence provides a 1.2 million year old continuous record of environmental and climatological variability in the Balkan Region. The age control can be further improved by first findings of macroscopic tephra horizons. Peaks in K, Sr, Zr, and magnetic
Investigation of Ni@CoO core-shell nanoparticle films synthesized by sequential layer deposition
NASA Astrophysics Data System (ADS)
Spadaro, M. C.; Luches, P.; Benedetti, F.; Valeri, S.; Turchini, S.; Bertoni, G.; Ferretti, A. M.; Capetti, E.; Ponti, A.; D'Addato, S.
2017-02-01
Films of Ni@CoO core-shell nanoparticles (NP Ni core size d ≈ 11 nm) have been grown on Si/SiOx and lacey carbon supports, by a sequential layer deposition method: a first layer of CoO was evaporated on the substrate, followed by the deposition of a layer of pre-formed, mass-selected Ni NPs, and finally an overlayer of CoO was added. The Ni NPs were formed by a magnetron gas aggregation source, and mass selected with a quadrupole mass filter. The morphology of the films was investigated with Scanning Electron Microscopy and Scanning Transmission Electron Microscopy. The Ni NP cores have a shape compatible with McKay icosahedron, caused by multitwinning occurring during their growth in the source, and the Ni NP layer shows the typical random paving growth mode. After the deposition of the CoO overlayer, CoO islands are observed, gradually extending and tending to merge with each other, with the formation of shells that enclose the Ni NP cores. In situ X-ray Photoelectron Spectroscopy showed that a few Ni atomic layers localized at the core-shell interface are oxidized, hinting at the possibility of creating an intermediate NiO shell between Ni and CoO, depending on the deposition conditions. Finally, X-ray Magnetic Circular Dichroism at the Ni L2,3 absorption edge showed the presence of magnetization at room temperature even at remanence, revealing the possibility of magnetic stabilization of the NP film.
Exploring cosmic origins with CORE: Mitigation of systematic effects
NASA Astrophysics Data System (ADS)
Natoli, P.; Ashdown, M.; Banerji, R.; Borrill, J.; Buzzelli, A.; de Gasperis, G.; Delabrouille, J.; Hivon, E.; Molinari, D.; Patanchon, G.; Polastri, L.; Tomasi, M.; Bouchet, F. R.; Henrot-Versillé, S.; Hoang, D. T.; Keskitalo, R.; Kiiveri, K.; Kisner, T.; Lindholm, V.; McCarthy, D.; Piacentini, F.; Perdereau, O.; Polenta, G.; Tristram, M.; Achucarro, A.; Ade, P.; Allison, R.; Baccigalupi, C.; Ballardini, M.; Banday, A. J.; Bartlett, J.; Bartolo, N.; Basak, S.; Baumann, D.; Bersanelli, M.; Bonaldi, A.; Bonato, M.; Boulanger, F.; Brinckmann, T.; Bucher, M.; Burigana, C.; Cai, Z.-Y.; Calvo, M.; Carvalho, C.-S.; Castellano, M. G.; Challinor, A.; Chluba, J.; Clesse, S.; Colantoni, I.; Coppolecchia, A.; Crook, M.; D'Alessandro, G.; de Bernardis, P.; De Zotti, G.; Di Valentino, E.; Diego, J.-M.; Errard, J.; Feeney, S.; Fernandez-Cobos, R.; Finelli, F.; Forastieri, F.; Galli, S.; Genova-Santos, R.; Gerbino, M.; González-Nuevo, J.; Grandis, S.; Greenslade, J.; Gruppuso, A.; Hagstotz, S.; Hanany, S.; Handley, W.; Hernandez-Monteagudo, C.; Hervías-Caimapo, C.; Hills, M.; Keihänen, E.; Kitching, T.; Kunz, M.; Kurki-Suonio, H.; Lamagna, L.; Lasenby, A.; Lattanzi, M.; Lesgourgues, J.; Lewis, A.; Liguori, M.; López-Caniego, M.; Luzzi, G.; Maffei, B.; Mandolesi, N.; Martinez-González, E.; Martins, C. J. A. P.; Masi, S.; Matarrese, S.; Melchiorri, A.; Melin, J.-B.; Migliaccio, M.; Monfardini, A.; Negrello, M.; Notari, A.; Pagano, L.; Paiella, A.; Paoletti, D.; Piat, M.; Pisano, G.; Pollo, A.; Poulin, V.; Quartin, M.; Remazeilles, M.; Roman, M.; Rossi, G.; Rubino-Martin, J.-A.; Salvati, L.; Signorelli, G.; Tartari, A.; Tramonte, D.; Trappe, N.; Trombetti, T.; Tucker, C.; Valiviita, J.; Van de Weijgaert, R.; van Tent, B.; Vennin, V.; Vielva, P.; Vittorio, N.; Wallis, C.; Young, K.; Zannoni, M.
2018-04-01
We present an analysis of the main systematic effects that could impact the measurement of CMB polarization with the proposed CORE space mission. We employ timeline-to-map simulations to verify that the CORE instrumental set-up and scanning strategy allow us to measure sky polarization to a level of accuracy adequate to the mission science goals. We also show how the CORE observations can be processed to mitigate the level of contamination by potentially worrying systematics, including intensity-to-polarization leakage due to bandpass mismatch, asymmetric main beams, pointing errors and correlated noise. We use analysis techniques that are well validated on data from current missions such as Planck to demonstrate how the residual contamination of the measurements by these effects can be brought to a level low enough not to hamper the scientific capability of the mission, nor significantly increase the overall error budget. We also present a prototype of the CORE photometric calibration pipeline, based on that used for Planck, and discuss its robustness to systematics, showing how CORE can achieve its calibration requirements. While a fine-grained assessment of the impact of systematics requires a level of knowledge of the system that can only be achieved in a future study phase, the analysis presented here strongly suggests that the main areas of concern for the CORE mission can be addressed using existing knowledge, techniques and algorithms.
NASA Astrophysics Data System (ADS)
Stockhecke, Mona; Beck, Catherine; Brown, Erik T.; Cohen, Andrew; Deocampo, Daniel M.; Feibel, Craig S.; Pelletier, Jon D.; Rabideaux, Nathane M.; Sier, Mark
2016-04-01
The Hominin Sites and Paleolakes Drilling Project (HSPDP), and the related Olorgesailie Drilling Project (ODP), recovered ~2 km of drill core since 2012. At the HSPDP West Turkana Kaitio (WTK) site a 216 m-long core that covers the Early Pleistocene time window (1.3 to 1.87 Ma) during which hominids first expanded out of Africa and marine records document reorganization of tropical climate and the development of the strong Walker circulation. WTK carries particular interest for paleoclimate and paleoenvironmental reconstructions as it is located only 2.5 km from the location of one of the most complete hominin skeletons ever recovered (Nariokotome Boy). XRF core scanning data provide a means of evaluating records of past environmental conditions continuously and at high resolution. However, the record contains complex lithologies reflecting repeated episodes of inundation and desiccation along a dynamic lake margin. Here we present a methodological approach to address the highly variable lithostratigraphy of the East African records to establish comprehensive paleoclimate timeseries. The power spectrum of the presented hydroclimate record peaks at Milankovitch cycles, qualifying HSPDP drill cores from the Turkana Basin to be used as high-resolution Early Pleistocene paleoclimate archive. Comparing these data with marine climate reconstructions sheds light into athmospheric processes and continental climate dynamics.
Direct Observation of Dislocation Core Structures in CdTe/GaAs(001).
McGibbon, A J; Pennycook, S J; Angelo, J E
1995-07-28
A strategy is presented for determining sublattice polarity at defects in compound semiconductors. Core structures of 60-degree and Lomer dislocations in the CdTe/GaAs(001) system have been obtained by the application of maximum-entropy analysis to Z-contrast images (Z is atomic number) obtained in a 300-kilovolt scanning transmission electron microscope. Sixty-degree dislocations were observed to be of the glide type, whereas in the case of Lomer dislocations, both a symmetric (Hornstra-like) core and an unexpected asymmetric structure made up of a fourfold ring were seen.
Role of XRF in the restoration of a prominent architectural monument at the site of Mleiha
NASA Astrophysics Data System (ADS)
Yousif, Eisa; Attaelmanan, Atta
2012-07-01
The fort at Mleiha is one of the most well known archaeological sites of its period (3rd c. BC to 3rd c. AD) in the United Arab Emirates and has provided much valuable information. The period of its construction and use coincided with the Parthian period, during which there were extensive commercial contacts between the UAE and Mediterranean cities, Egypt, Mesopotamia, Southwest Iran, Pakistan, East Africa, and the southern Arabian Peninsula. It was restored using local materials, and traditional construction methods. The objective of this study was to utilize XRF techniques for the identification of the elemental composition of building material used to construct an archaeological fort, and to compare it to composition of the restoration material. Results of the study show strong correlation between the original fort building material and those used for restoration.
Lee, Ban Seok; Cho, Chang-Min; Jung, Min Kyu; Jang, Jung Sik; Bae, Han Ik
2017-07-15
The superiority of endoscopic ultrasound-guided fine needle biopsy (EUS-FNB) over EUS-guided fine needle aspiration (EUS-FNA) remains controversial. Given the lack of studies analyzing histologic specimens acquired from EUS-FNB or EUS-FNA, we compared the proportion of the histologic core obtained from both techniques. A total of 58 consecutive patients with solid mass lesions were enrolled and randomly assigned to the EUS-FNA or EUS-FNB groups. The opposite needle was used after the failure of core tissue acquisition using the initial needle with up to three passes. Using computerized analyses of the scanned histologic slide, the overall area and the area of the histologic core portion in specimens obtained by the two techniques were compared. No significant differences were identified between the two groups with respect to demographic and clinical characteristics. Fewer needle passes were required to obtain core specimens in the FNB group (p<0.001). There were no differences in the proportion of histologic core (11.8%±19.5% vs 8.0%±11.1%, p=0.376) or in the diagnostic accuracy (80.6% vs 81.5%, p=0.935) between two groups. The proportion of histologic core and the diagnostic accuracy were comparable between the FNB and FNA groups. However, fewer needle passes were required to establish an accurate diagnosis in EUS-FNB.
Sub-nanosecond time-resolved near-field scanning magneto-optical microscope.
Rudge, J; Xu, H; Kolthammer, J; Hong, Y K; Choi, B C
2015-02-01
We report on the development of a new magnetic microscope, time-resolved near-field scanning magneto-optical microscope, which combines a near-field scanning optical microscope and magneto-optical contrast. By taking advantage of the high temporal resolution of time-resolved Kerr microscope and the sub-wavelength spatial resolution of a near-field microscope, we achieved a temporal resolution of ∼50 ps and a spatial resolution of <100 nm. In order to demonstrate the spatiotemporal magnetic imaging capability of this microscope, the magnetic field pulse induced gyrotropic vortex dynamics occurring in 1 μm diameter, 20 nm thick CoFeB circular disks has been investigated. The microscope provides sub-wavelength resolution magnetic images of the gyrotropic motion of the vortex core at a resonance frequency of ∼240 MHz.
A methodology of SiP testing based on boundary scan
NASA Astrophysics Data System (ADS)
Qin, He; Quan, Haiyang; Han, Yifei; Zhu, Tianrui; Zheng, Tuo
2017-10-01
System in Package (SiP) play an important role in portable, aerospace and military electronic with the microminiaturization, light weight, high density, and high reliability. At present, SiP system test has encountered the problem on system complexity and malfunction location with the system scale exponentially increase. For SiP system, this paper proposed a testing methodology and testing process based on the boundary scan technology. Combining the character of SiP system and referencing the boundary scan theory of PCB circuit and embedded core test, the specific testing methodology and process has been proposed. The hardware requirement of the under test SiP system has been provided, and the hardware platform of the testing has been constructed. The testing methodology has the character of high test efficiency and accurate malfunction location.
Observation of hole accumulation in Ge/Si core/shell nanowires using off-axis electron holography.
Li, Luying; Smith, David J; Dailey, Eric; Madras, Prashanth; Drucker, Jeff; McCartney, Martha R
2011-02-09
Hole accumulation in Ge/Si core/shell nanowires (NWs) has been observed and quantified using off-axis electron holography and other electron microscopy techniques. The epitaxial [110]-oriented Ge/Si core/shell NWs were grown on Si (111) substrates by chemical vapor deposition through the vapor-liquid-solid growth mechanism. High-angle annular-dark-field scanning transmission electron microscopy images and off-axis electron holograms were obtained from specific NWs. The excess phase shifts measured by electron holography across the NWs indicated the presence of holes inside the Ge cores. Calculations based on a simplified coaxial cylindrical model gave hole densities of (0.4 ± 0.2) /nm(3) in the core regions.
NASA Astrophysics Data System (ADS)
Chang, C.; Kenna, T. C.; Nitsche, F. O.
2016-12-01
The IPCC predicts that the frequency and severity of storms worldwide will increase due to climate change, a growing concern for the highly populated coastal areas near the Hudson River estuary. Storms have the potential to change the river's sediment budget, and it is necessary to update the current understanding of the effect of storms on sediment dynamics. In 2011, Tropical Storm Lee and Hurricane Irene delivered over 2.7 million tons of sediment to the Hudson River including over 1.5 million tons from the Mohawk River, a freshwater tributary, in addition to record amounts contributed from other major tributaries. The goals of this project are to use sediment elemental compositions to trace the major tributaries contributing to this storm-deposited sediment and to determine where sediment is accumulating as a result of storm activity. Chemical analysis of over 800 archived sediment samples are compiled to provide a pre-storm background level. These samples are compared to newly deposited sediment and material from specific tributaries. Elemental abundances (K, Ca, Ti, Cr, Mn, Fe, Co, Cu, Zn, Rb, Sr, Zr, Pb, and U) are measured using a field portable X-Ray Fluorescence (XRF) unit and core scanning XRF unit. Bulk matrix density is measured using a pycnometer. The measurements are used to identify elemental signatures from tributary sediment and to trace the influence of specific tributaries on deposition through the river. Our results suggests measureable signatures in sediment from individual tributaries. The Mohawk River contributes high concentrations of Ca due to the calcite deposits in its watershed. XRF measurements also show the effect of human activity on sediment deposition; variations in Rb and Zr indicate changes in deposition due to dredging in Haverstraw Bay. The salt wedge front, where ocean and fresh water meets is evident in areas of below average matrix density. This project shows significant geochemical variability between sediment from different
NASA Astrophysics Data System (ADS)
Ohlendorf, Christian; Gebhardt, Catalina; Hahn, Annette; Kliem, Pierre; Zolitschka, Bernd
2011-07-01
Using the ICDP (International Continental Scientific Drilling Program) deep lake drilling expedition no. 5022 as an example, we describe core processing and sampling procedures as well as new tools developed for subsampling. A manual core splitter is presented that is (1) mobile, (2) able to cut plastic core liners lengthwise without producing swarf of liner material and (3) consists of off-the-shelf components. In order to improve the sampling of sediment cores, a new device, the core sampling assembly (CSA), was developed that meets the following targets: (1) the partitioning of the sediment into discs of equal thickness is fast and precise, (2) disturbed sediment at the inner surface of the liner is discarded during this sampling process, (3) usage of the available sediment is optimised, (4) subsamples are volumetric and oriented, and (5) identical subsamples are taken. The CSA can be applied to D-shaped split sediment cores of any diameter and consists of a divider and a D-shaped scoop. The sampling plan applied for ICDP expedition 5022 is illustrated and may be used as a guideline for planning the efficient partitioning of sediment amongst different lake research groups involved in multidisciplinary projects. For every subsample, the use of quality flags is suggested (1) to document the sample condition, (2) to give a first sediment classification and (3) to guarantee a precise adjustment of logging and scanning data with data determined on individual samples. Based on this, we propose a protocol that might be applied across lake drilling projects in order to facilitate planning and documentation of sampling campaigns and to ensure a better comparability of results.
NASA Astrophysics Data System (ADS)
Wingen, A.; Wilcox, R. S.; Seal, S. K.; Unterberg, E. A.; Cianciosa, M. R.; Delgado-Aparicio, L. F.; Hirshman, S. P.; Lao, L. L.
2018-03-01
Large, spontaneous m/n = 1/1 helical cores are shown to be expected in tokamaks such as ITER with extended regions of low- or reversed- magnetic shear profiles and q near 1 in the core. The threshold for this spontaneous symmetry breaking is determined using VMEC scans, beginning with reconstructed 3D equilibria from DIII-D and Alcator C-Mod based on observed internal 3D deformations. The helical core is a saturated internal kink mode (Wesson 1986 Plasma Phys. Control. Fusion 28 243); its onset threshold is shown to be proportional to (dp/dρ)/B_t2 around q = 1. Below the threshold, applied 3D fields can drive a helical core to finite size, as in DIII-D. The helical core size thereby depends on the magnitude of the applied perturbation. Above it, a small, random 3D kick causes a bifurcation from axisymmetry and excites a spontaneous helical core, which is independent of the kick size. Systematic scans of the q-profile show that the onset threshold is very sensitive to the q-shear in the core. Helical cores occur frequently in Alcator C-Mod during ramp-up when slow current penetration results in a reversed shear q-profile, which is favorable for helical core formation. Finally, a comparison of the helical core onset threshold for discharges from DIII-D, Alcator C-Mod and ITER confirms that while DIII-D is marginally stable, Alcator C-Mod and especially ITER are highly susceptible to helical core formation without being driven by an externally applied 3D magnetic field.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Wingen, A.; Wilcox, R. S.; Seal, S. K.
In this paper, large, spontaneous m/n = 1/1 helical cores are shown to be expected in tokamaks such as ITER with extended regions of low- or reversed- magnetic shear profiles and q near 1 in the core. The threshold for this spontaneous symmetry breaking is determined using VMEC scans, beginning with reconstructed 3D equilibria from DIII-D and Alcator C-Mod based on observed internal 3D deformations. The helical core is a saturated internal kink mode (Wesson 1986 Plasma Phys. Control. Fusion 28 243); its onset threshold is shown to be proportional tomore » $$({\\rm d}p/{\\rm d}\\rho)/B_t^2$$ around q = 1. Below the threshold, applied 3D fields can drive a helical core to finite size, as in DIII-D. The helical core size thereby depends on the magnitude of the applied perturbation. Above it, a small, random 3D kick causes a bifurcation from axisymmetry and excites a spontaneous helical core, which is independent of the kick size. Systematic scans of the q-profile show that the onset threshold is very sensitive to the q-shear in the core. Helical cores occur frequently in Alcator C-Mod during ramp-up when slow current penetration results in a reversed shear q-profile, which is favorable for helical core formation. In conclusion, a comparison of the helical core onset threshold for discharges from DIII-D, Alcator C-Mod and ITER confirms that while DIII-D is marginally stable, Alcator C-Mod and especially ITER are highly susceptible to helical core formation without being driven by an externally applied 3D magnetic field.« less
Wingen, A.; Wilcox, R. S.; Seal, S. K.; ...
2018-01-15
In this paper, large, spontaneous m/n = 1/1 helical cores are shown to be expected in tokamaks such as ITER with extended regions of low- or reversed- magnetic shear profiles and q near 1 in the core. The threshold for this spontaneous symmetry breaking is determined using VMEC scans, beginning with reconstructed 3D equilibria from DIII-D and Alcator C-Mod based on observed internal 3D deformations. The helical core is a saturated internal kink mode (Wesson 1986 Plasma Phys. Control. Fusion 28 243); its onset threshold is shown to be proportional tomore » $$({\\rm d}p/{\\rm d}\\rho)/B_t^2$$ around q = 1. Below the threshold, applied 3D fields can drive a helical core to finite size, as in DIII-D. The helical core size thereby depends on the magnitude of the applied perturbation. Above it, a small, random 3D kick causes a bifurcation from axisymmetry and excites a spontaneous helical core, which is independent of the kick size. Systematic scans of the q-profile show that the onset threshold is very sensitive to the q-shear in the core. Helical cores occur frequently in Alcator C-Mod during ramp-up when slow current penetration results in a reversed shear q-profile, which is favorable for helical core formation. In conclusion, a comparison of the helical core onset threshold for discharges from DIII-D, Alcator C-Mod and ITER confirms that while DIII-D is marginally stable, Alcator C-Mod and especially ITER are highly susceptible to helical core formation without being driven by an externally applied 3D magnetic field.« less
NASA Astrophysics Data System (ADS)
Rabideaux, N. M.; Chaudhary, M. S.; Deocampo, D.; Feibel, C. S.; Cohen, A. S.
2016-12-01
The Hominin Sites and Paleolakes Drilling Project (HSPDP) collected sediment cores from six rift basins in Ethiopia and Kenya. The goal of HSPDP is to construct high-resolution records of environmental change, and to understand how those changes relate to early human evolution and cultural adaptations. The West Turkana-Kaitio (WTK) site was targeted due to the abundant archeological and paleontological artifacts and fossils discovered around the basin. We conducted XRD and XRF analyses on HSPDP-WTK core material to construct a high-resolution record of paleoenvironmental conditions in the Kenya Rift during the Early Pleistocene ( 1.9-1.35 Ma). Mineralogical and geochemical trends were also used to identify the diagenetic history of fluviolacustrine sediments in the basin. The bulk mineralogy is comprised of mostly detrital feldspars, muscovite, α-quartz, and carbonates. Zeolites are present in intervals throughout the core, possibly suggesting pulses of increased salinity. Oxides and S-bearing minerals are abundant from 100-170 mbs, which may be indicative of redox and or hydrothermal processes in that interval. The lowermost portion of the core contains α- and β-quartz, pyrite and zeolites, suggesting either low-oxygen saline conditions or hydrothermal activity. Oriented clay analysis indicated multiple intervals of diagenesis, with the illitization of smectite related to hydrothermal and or microbial activity. Clay analysis provided evidence for a low degree of illitization in the upper portion of the core, whereas mixed-layered illite-smectite (I/S) contained 30-50% illite proximal to fault breccia and up to 70% illite below the faulted section, indicative of significant alteration in the lowermost portion of the core. Coupled mineralogical and geochemical analysis revealed a complex alteration history in the basin indicated by: 1) the presence of mixed-layer I/S throughout the 216 m core; 2) pronounced alteration proximal to faulting; and 3) authigenic
NASA Astrophysics Data System (ADS)
Martin-Puertas, Celia; Tjallingii, Rik; Bloemsma, Menno; Brauer, Achim
2015-04-01
The annually laminated record of the Lake Meerfelder Maar (Germany) is one of the most significant paleoclimatic archives in central Europe because of i) its robust chronology based on varve counting and tephrochronology, and ii) its very high sensitivity to the North Atlantic climate variability. In this study, varve thickness and micro X-ray fluorescence (XRF) data are combined with the published decadal to centennial resolved pollen assemblage between 11,700 to 9,000 yr BP. This period covers two major biostratigraphic stages in Europe, i.e. the Preboreal and the Boreal climatic periods. We focus on the timing and duration of the Preboreal-Boreal climatic transition, as well as short-lived cooling events in the North Atlantic region such as the Preboreal Oscillation (PBO). Due to the predominantly basaltic composition of the MFM catchment, we use normalized Titanium (Ti) intensities as a proxy for detrital influx. This is in close agreement with changes in varve thickness indicating that the lake variability is mainly driven by the annual detrital discharge into the lake. Statistical clustering of the XRF data reveals six chemo-stratigraphic units coinciding with major changes in local vegetation. The stratigraphical boundary coinciding with the Preboreal-Boreal transition is dated at 10,690 varve yr BP. This is characterized by an abrupt increase in detrital material, likely because of a change to wetter conditions in the central Europe. Although the PBO is not clearly identified in the MFM pollen record, a individual cluster from 11,230 to 11,020 varve yr BP broadly coincides with the timing of the PBO in the North Atlantic region, suggesting this cool event lasted ca 200 years in central Europe. The most significant change in the lake occurred between 9,655 and 10,530 varve yr BP, when detrital influx nearly completely ceased and varves were poorly preserved. However, this interval within the Boreal period has no counterpart in the pollen record and
Harper, Martin; Pacolay, Bruce; Hintz, Patrick; Andrew, Michael E
2006-03-01
Personal and area samples for airborne lead were taken at a lead mine concentrator mill, and at a lead-acid battery recycler. Lead is mined as its sulfidic ore, galena, which is often associated with zinc and silver. The ore typically is concentrated, and partially separated, on site by crushing and differential froth flotation of the ore minerals before being sent to a primary smelter. Besides lead, zinc and iron are also present in the airborne dusts, together with insignificant levels of copper and silver, and, in one area, manganese. The disposal of used lead-acid batteries presents environmental issues, and is also a waste of recoverable materials. Recycling operations allow for the recovery of lead, which can then be sold back to battery manufacturers to form a closed loop. At the recycling facility lead is the chief airborne metal, together with minor antimony and tin, but several other metals are generally present in much smaller quantities, including copper, chromium, manganese and cadmium. Samplers used in these studies included the closed-face 37 mm filter cassette (the current US standard method for lead sampling), the 37 mm GSP or "cone" sampler, the 25 mm Institute of Occupational Medicine (IOM) inhalable sampler, the 25 mm Button sampler, and the open-face 25 mm cassette. Mixed cellulose-ester filters were used in all samplers. The filters were analyzed after sampling for their content of the various metals, particularly lead, that could be analyzed by the specific portable X-ray fluorescence (XRF) analyzer under study, and then were extracted with acid and analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES). The 25 mm filters were analyzed using a single XRF reading, while three readings on different parts of the filter were taken from the 37 mm filters. For lead at the mine concentrate mill, all five samplers gave good correlations (r2 > 0.96) between the two analytical methods over the entire range of found lead mass
Nakano, Yoshio; Katakuse, Yoshimitsu; Azechi, Yasutaka
2018-06-01
An attempt to apply X-Ray Fluorescence (XRF) analysis to evaluate small particle coating process as a Process Analytical Technologies (PAT) was made. The XRF analysis was used to monitor coating level in small particle coating process with at-line manner. The small particle coating process usually consists of multiple coating processes. This study was conducted by a simple coating particles prepared by first coating of a model compound (DL-methionine) and second coating by talc on spherical microcrystalline cellulose cores. The particles with two layered coating are enough to demonstrate the small particle coating process. From the result by the small particle coating process, it was found that the XRF signal played different roles, resulting that XRF signals by first coating (layering) and second coating (mask coating) could demonstrate the extent with different mechanisms for the coating process. Furthermore, the particle coating of the different particle size has also been investigated to evaluate size effect of these coating processes. From these results, it was concluded that the XRF could be used as a PAT in monitoring particle coating processes and become powerful tool in pharmaceutical manufacturing.
Landed XRD/XRF analysis of prime targets in the search for past or present Martian life.
Vaniman, D; Bish, D; Blake, D; Elliott, S T; Sarrazin, P; Collins, S A; Chipera, S
1998-12-25
Mars landers seeking evidence for past or present life will be guided by information from orbital mapping and from previous surface exploration. Several target options have been proposed, including sites that may harbor extant life and sites most likely to preserve evidence of past life These sites have specific mineralogic characteristics. Extant life might be gathered around the sinters and associated mineral deposits of rare active fumaroles, or held within brine pockets and inclusions in a few evaporite-mineral deposits. Possibilities for fossilization include deltaic and lake-bottom sediments of once-flooded craters, sinters formed by ancient hot-spring deposits, and the carbonate deposits associated with some evaporite systems. However, the highly varied mineralogy of fossil occurrences on Earth leads to the inference that Mars, an equally complex planet, could host a broad variety of potential fossilizing deposits. The abundance of volcanic systems on Mars and evidence for close associations between volcanism and water release suggest possibilities of organism entrapment and mineralization in volcaniclastic deposits, as found in some instances on Earth. Thus the targets being considered for exploration include a wide variety of unique deposits that would be characterized by silica or various nonsilicate minerals. Beyond these "special" deposits and in the most general case, an ability to distinguish mineralized from uncemented volcanic detritus may be the key to success in finding possible fossil-bearing authigenic mineralogies. A prototype miniaturized X ray diffraction/X ray fluorescence (XRD/XRF) instrument has been evaluated with silica, carbonate, and sulfate minerals and with a basalt, to examine the capabilities of this tool in mineralogic and petrologic exploration for exobiological goals. This instrument. CHEMIN (chemical and mineralogical analyzer), is based on an innovative low-power X ray tube, transmission geometry, and CCD collection and
Reduced thermal sensitivity of hybrid air-core photonic band-gap fiber ring resonator
NASA Astrophysics Data System (ADS)
Feng, Li-shuang; Wang, Kai; Jiao, Hong-chen; Wang, Jun-jie; Liu, Dan-ni; Yang, Zhao-hua
2018-01-01
A novel hybrid air-core photonic band-gap fiber (PBF) ring resonator with twin 90° polarization-axis rotated splices is proposed and demonstrated. Frist, we measure the temperature dependent birefringence coefficient of air-core PBF and Panda fiber. Experimental results show that the relative temperature dependent birefringence coefficient of air-core PBF is 1.42×10-8/°C, which is typically 16 times less than that of Panda fiber. Then, we extract the geometry profile of air-core PBF from scanning electron microscope (SEM) images. Numerical modal is built to distinguish the fast axis and slow axis in the fiber. By precisely setting the length difference in air-core PBF and Panda fiber between two 90° polarization-axis rotated splicing points, the hybrid air-core PBF ring resonator is constructed, and the finesse of the resonator is 8.4. Environmental birefringence variation induced by temperature change can be well compensated, and experimental results show an 18-fold reduction in thermal sensitivity, compared with resonator with twin 0° polarization-axis rotated splices.
Synthesis and cytotoxicity study of magnesium ferrite-gold core-shell nanoparticles.
Nonkumwong, Jeeranan; Pakawanit, Phakkhananan; Wipatanawin, Angkana; Jantaratana, Pongsakorn; Ananta, Supon; Srisombat, Laongnuan
2016-04-01
In this work, the core-magnesium ferrite (MgFe2O4) nanoparticles were prepared by hydrothermal technique. Completed gold (Au) shell coating on the surfaces of MgFe2O4 nanoparticles was obtained by varying core/shell ratios via a reduction method. Phase identification, morphological evolution, optical properties, magnetic properties and cytotoxicity to mammalian cells of these MgFe2O4 core coated with Au nanoparticles were examined by using a combination of X-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy, UV-visible spectroscopy (UV-vis), vibrating sample magnetometry and resazurin microplate assay techniques. In general, TEM images revealed different sizes of the core-shell nanoparticles generated from various core/shell ratios and confirmed the completed Au shell coating on MgFe2O4 core nanoparticles via suitable core/shell ratio with particle size less than 100 nm. The core-shell nanoparticle size and the quality of coating influence the optical properties of the products. The UV-vis spectra of complete coated MgFe2O4-Au core-shell nanoparticles exhibit the absorption bands in the near-Infrared (NIR) region indicating high potential for therapeutic applications. Based on the magnetic property measurement, it was found that the obtained MgFe2O4-Au core-shell nanoparticles still exhibit superparamagnetism with lower saturation magnetization value, compared with MgFe2O4 core. Both of MgFe2O4 and MgFe2O4-Au core-shell also showed in vitro non-cytotoxicity to mouse areola fibroblast (L-929) cell line. Copyright © 2015 Elsevier B.V. All rights reserved.
Fast scanning mode and its realization in a scanning acoustic microscope
NASA Astrophysics Data System (ADS)
Ju, Bing-Feng; Bai, Xiaolong; Chen, Jian
2012-03-01
The scanning speed of the two-dimensional stage dominates the efficiency of mechanical scanning measurement systems. This paper focused on a detailed scanning time analysis of conventional raster and spiral scan modes and then proposed two fast alternative scanning modes. Performed on a self-developed scanning acoustic microscope (SAM), the measured images obtained by using the conventional scan mode and fast scan modes are compared. The total scanning time is reduced by 29% of the two proposed fast scan modes. It will offer a better solution for high speed scanning without sacrificing the system stability, and will not introduce additional difficulties to the configuration of scanning measurement systems. They can be easily applied to the mechanical scanning measuring systems with different driving actuators such as piezoelectric, linear motor, dc motor, and so on. The proposed fast raster and square spiral scan modes are realized in SAM, but not specially designed for it. Therefore, they have universal adaptability and can be applied to other scanning measurement systems with two-dimensional mechanical scanning stages, such as atomic force microscope or scanning tunneling microscope.
NASA Technical Reports Server (NTRS)
Zeigler, Ryan A.
2014-01-01
An integral part of any sample return mission is the initial description and classification of returned samples by the preliminary examination team (PET). The goal of a PET is to characterize and classify the returned samples, making this information available to the general research community who can then conduct more in-depth studies on the samples. A PET strives to minimize the impact their work has on the sample suite, which often limits the PET work to largely visual measurements and observations like optical microscopy. More modern techniques can also be utilized by future PET to nondestructively characterize astromaterials in a more rigorous way. Here we present our recent analyses of Apollo samples 14321 and 14305 by micro-CT and micro-XRF (respectively), assess the potential for discovery of "new" Apollo samples for scientific study, and evaluate the usefulness of these techniques in future PET efforts.
Recommendations for the design and the installation of large laser scanning microscopy systems
NASA Astrophysics Data System (ADS)
Helm, P. Johannes
2012-03-01
Laser Scanning Microscopy (LSM) has since the inventions of the Confocal Scanning Laser Microscope (CLSM) and the Multi Photon Laser Scanning Microscope (MPLSM) developed into an essential tool in contemporary life science and material science. The market provides an increasing number of turn-key and hands-off commercial LSM systems, un-problematic to purchase, set up and integrate even into minor research groups. However, the successful definition, financing, acquisition, installation and effective use of one or more large laser scanning microscopy systems, possibly of core facility character, often requires major efforts by senior staff members of large academic or industrial units. Here, a set of recommendations is presented, which are helpful during the process of establishing large systems for confocal or non-linear laser scanning microscopy as an effective operational resource in the scientific or industrial production process. Besides the description of technical difficulties and possible pitfalls, the article also illuminates some seemingly "less scientific" processes, i.e. the definition of specific laboratory demands, advertisement of the intention to purchase one or more large systems, evaluation of quotations, establishment of contracts and preparation of the local environment and laboratory infrastructure.
Jamroskovic, Jan; Shao, Paul P; Suvorova, Elena; Barak, Imrich; Bernier-Latmani, Rizlan
2014-09-01
Endospores (also referred to as bacterial spores) are bacterial structures formed by several bacterial species of the phylum Firmicutes. Spores form as a response to environmental stress. These structures exhibit remarkable resistance to harsh environmental conditions such as exposure to heat, desiccation, and chemical oxidants. The spores include several layers of protein and peptidoglycan that surround a core harboring DNA as well as high concentrations of calcium and dipicolinic acid (DPA). A combination of scanning transmission X-ray microscopy, scanning transmission electron microscopy, and energy dispersive spectroscopy was used for the direct quantitative characterization of bacterial spores. The concentration and localization of DPA, Ca(2+) , and other elements were determined and compared for the core and cortex of spores from two distinct genera: Bacillus subtilis and Desulfotomaculum reducens. This micro-spectroscopic approach is uniquely suited for the direct study of individual bacterial spores, while classical molecular and biochemical methods access only bulk characteristics. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.
CAT scan - pelvis; Computed axial tomography scan - pelvis; Computed tomography scan - pelvis; CT scan - pelvis ... Risks of CT scans include: Being exposed to radiation Allergic reaction to contrast dye CT scans do expose you to more radiation ...
CAT scan - shoulder; Computed axial tomography scan - shoulder; Computed tomography scan - shoulder; CT scan - shoulder ... Risks of CT scans include: Being exposed to radiation Allergic reaction to contrast dye Birth defect if done during pregnancy CT scans ...
Large-area super-resolution optical imaging by using core-shell microfibers
NASA Astrophysics Data System (ADS)
Liu, Cheng-Yang; Lo, Wei-Chieh
2017-09-01
We first numerically and experimentally report large-area super-resolution optical imaging achieved by using core-shell microfibers. The particular spatial electromagnetic waves for different core-shell microfibers are studied by using finite-difference time-domain and ray tracing calculations. The focusing properties of photonic nanojets are evaluated in terms of intensity profile and full width at half-maximum along propagation and transversal directions. In experiment, the general optical fiber is chemically etched down to 6 μm diameter and coated with different metallic thin films by using glancing angle deposition. The direct imaging of photonic nanojets for different core-shell microfibers is performed with a scanning optical microscope system. We show that the intensity distribution of a photonic nanojet is highly related to the metallic shell due to the surface plasmon polaritons. Furthermore, large-area super-resolution optical imaging is performed by using different core-shell microfibers placed over the nano-scale grating with 150 nm line width. The core-shell microfiber-assisted imaging is achieved with super-resolution and hundreds of times the field-of-view in contrast to microspheres. The possible applications of these core-shell optical microfibers include real-time large-area micro-fluidics and nano-structure inspections.
NASA Astrophysics Data System (ADS)
Kassem, A.; Sawan, M.; Boukadoum, M.; Haidar, A.
2005-12-01
We are concerned with the design, implementation, and validation of a perception SoC based on an ultrasonic array of sensors. The proposed SoC is dedicated to ultrasonic echography applications. A rapid prototyping platform is used to implement and validate the new architecture of the digital signal processing (DSP) core. The proposed DSP core efficiently integrates all of the necessary ultrasonic B-mode processing modules. It includes digital beamforming, quadrature demodulation of RF signals, digital filtering, and envelope detection of the received signals. This system handles 128 scan lines and 6400 samples per scan line with a[InlineEquation not available: see fulltext.] angle of view span. The design uses a minimum size lookup memory to store the initial scan information. Rapid prototyping using an ARM/FPGA combination is used to validate the operation of the described system. This system offers significant advantages of portability and a rapid time to market.
NASA Astrophysics Data System (ADS)
Fraser, Nicholas; Kuhnt, Wolfgang; Holbourn, Ann; Bolliet, Timothé; Andersen, Nils; Blanz, Thomas; Beaufort, Luc
2014-11-01
Proxy records of hydrologic variability in the West Pacific Warm Pool (WPWP) have revealed wide-scale changes in past convective activity in response to orbital and suborbital climate forcings. However, attributing proxy responses to regional changes in WPWP hydrology versus local variations in precipitation requires independent records linking the terrestrial and marine realms. We present high-resolution stable isotope, UK'37 sea surface temperature, X-ray fluorescence (XRF) core scanning, and coccolithophore-derived paleoproductivity records covering the past 120 ka from International Marine Global Change (IMAGES) Program Core MD06-3075 (6°29'N, 125°50'E, water depth 1878 m), situated in the Davao Gulf on the southern side of Mindanao. XRF-derived log(Fe/Ca) records provide a robust proxy for runoff-driven sedimentary discharge from Mindanao, while past changes in local productivity are associated with variable freshwater runoff and stratification of the surface layer. Significant precessional-scale variability in sedimentary discharge occurred during marine isotope stage (MIS) 5, with peaks in discharge contemporaneous with Northern Hemisphere summer insolation minima. We attribute these changes to the latitudinal migration of the Intertropical Convergence Zone (ITCZ) over the WPWP together with variability in the strength of the Walker circulation acting on precessional timescales. Between 60 and 15 ka sedimentary discharge at Mindanao was muted, displaying little orbital- or millennial-scale variability, likely in response to weakened precessional insolation forcing and lower sea level driving increased subsidence of air masses over the exposed Sunda Shelf. These results highlight the high degree of local variability in the precipitation response to past climate changes in the WPWP.
CAT scan - sinus; Computed axial tomography scan - sinus; Computed tomography scan - sinus; CT scan - sinus ... Risks for a CT scan includes: Being exposed to radiation Allergic reaction to contrast dye CT scans expose you to more radiation than regular ...
ScanImage: flexible software for operating laser scanning microscopes.
Pologruto, Thomas A; Sabatini, Bernardo L; Svoboda, Karel
2003-05-17
Laser scanning microscopy is a powerful tool for analyzing the structure and function of biological specimens. Although numerous commercial laser scanning microscopes exist, some of the more interesting and challenging applications demand custom design. A major impediment to custom design is the difficulty of building custom data acquisition hardware and writing the complex software required to run the laser scanning microscope. We describe a simple, software-based approach to operating a laser scanning microscope without the need for custom data acquisition hardware. Data acquisition and control of laser scanning are achieved through standard data acquisition boards. The entire burden of signal integration and image processing is placed on the CPU of the computer. We quantitate the effectiveness of our data acquisition and signal conditioning algorithm under a variety of conditions. We implement our approach in an open source software package (ScanImage) and describe its functionality. We present ScanImage, software to run a flexible laser scanning microscope that allows easy custom design.
Line-scanning, stage scanning confocal microscope
NASA Astrophysics Data System (ADS)
Carucci, John A.; Stevenson, Mary; Gareau, Daniel
2016-03-01
We created a line-scanning, stage scanning confocal microscope as part of a new procedure: video assisted micrographic surgery (VAMS). The need for rapid pathological assessment of the tissue on the surface of skin excisions very large since there are 3.5 million new skin cancers diagnosed annually in the United States. The new design presented here is a confocal microscope without any scanning optics. Instead, a line is focused in space and the sample, which is flattened, is physically translated such that the line scans across its face in a direction perpendicular to the line its self. The line is 6mm long and the stage is capable of scanning 50 mm, hence the field of view is quite large. The theoretical diffraction-limited resolution is 0.7um lateral and 3.7um axial. However, in this preliminary report, we present initial results that are a factor of 5-7 poorer in resolution. The results are encouraging because they demonstrate that the linear array detector measures sufficient signal from fluorescently labeled tissue and also demonstrate the large field of view achievable with VAMS.
NASA Astrophysics Data System (ADS)
McCanta, Molly C.; Hatfield, Robert G.; Thomson, Bradley J.; Hook, Simon J.; Fisher, Elizabeth
2015-12-01
Understanding the frequency, magnitude, and nature of explosive volcanic eruptions is essential for hazard planning and risk mitigation. Terrestrial stratigraphic tephra records can be patchy and incomplete due to subsequent erosion and burial processes. In contrast, the marine sedimentary record commonly preserves a more complete historical record of volcanic activity as individual events are archived within continually accumulating background sediments. While larger tephra layers are often identifiable by changes in sediment color and/or texture, smaller fallout layers may also be present that are not visible to the naked eye. These cryptotephra are commonly more difficult to identify and often require time-consuming and destructive point counting, petrography, and microscopy work. Here we present several rapid, nondestructive, and quantitative core scanning methodologies (magnetic susceptibility, visible to shortwave infrared spectroscopy, and XRF core scanning) which, when combined, can be used to identify the presence of increased volcaniclastic components (interpreted to be cryptotephra) in the sedimentary record. We develop a new spectral parameter (BDI1000VIS) that exploits the absorption of the 1 µm near-infrared band in tephra. Using predetermined mixtures, BDI1000VIS can accurately identify tephra layers in concentrations >15-20%. When applied to the upper ˜270 kyr record of IODP core U1396C from the Caribbean Sea, and verified by traditional point counting, 29 potential cryptotephra layers were identified as originating from eruptions of the Lesser Antilles Volcanic Arc. Application of these methods in future coring endeavors can be used to minimize the need for physical disaggregation of valuable drill core material and allow for near-real-time recognition of tephra units, both visible and cryptotephra. This article was corrected on 23 DEC 2015. See the end of the full text for details.
CVD graphene sheets electrochemically decorated with "core-shell" Co/CoO nanoparticles
NASA Astrophysics Data System (ADS)
Bayev, V. G.; Fedotova, J. A.; Kasiuk, J. V.; Vorobyova, S. A.; Sohor, A. A.; Komissarov, I. V.; Kovalchuk, N. G.; Prischepa, S. L.; Kargin, N. I.; Andrulevičius, M.; Przewoznik, J.; Kapusta, Cz.; Ivashkevich, O. A.; Tyutyunnikov, S. I.; Kolobylina, N. N.; Guryeva, P. V.
2018-05-01
The paper reports on the first successful fabrication of Co-graphene composites by electrochemical deposition of Co nanoparticles (NPs) on the sheets of twisted graphene. Characterization of the surface morphology and element mapping of twisted graphene decorated with Co NPs by transmission and scanning electron microscopy in combination with the energy-dispersive X-ray spectroscopy reveals the formation of isolated quasi-spherical oxidized Co NPs with the mean diameter 〈 d〉 ≈ 220 nm and core-shell structure. X-ray photoelectron spectroscopy indicates that the core of deposited NPs consists of metal Co while the shell is CoO. Composite Co-graphene samples containing core-shell NPs reveal an exchange bias field up to 160 Oe at 4 K as detected by vibrating sample magnetometry after the field cooling procedure.
Tank 241-T-204, core 188 analytical results for the final report
DOE Office of Scientific and Technical Information (OSTI.GOV)
Nuzum, J.L.
TANK 241-T-204, CORE 188, ANALYTICAL RESULTS FOR THE FINAL REPORT. This document is the final laboratory report for Tank 241 -T-204. Push mode core segments were removed from Riser 3 between March 27, 1997, and April 11, 1997. Segments were received and extruded at 222-8 Laboratory. Analyses were performed in accordance with Tank 241-T-204 Push Mode Core Sampling and analysis Plan (TRAP) (Winkleman, 1997), Letter of instruction for Core Sample Analysis of Tanks 241-T-201, 241- T-202, 241-T-203, and 241-T-204 (LAY) (Bell, 1997), and Safety Screening Data Qual@ Objective (DO) ODukelow, et al., 1995). None of the subsamples submitted for totalmore » alpha activity (AT) or differential scanning calorimetry (DC) analyses exceeded the notification limits stated in DO. The statistical results of the 95% confidence interval on the mean calculations are provided by the Tank Waste Remediation Systems Technical Basis Group and are not considered in this report.« less
Strain-Driven Stacking Faults in CdSe/CdS Core/Shell Nanorods.
Demortière, Arnaud; Leonard, Donovan N; Petkov, Valeri; Chapman, Karena; Chattopadhyay, Soma; She, Chunxing; Cullen, David A; Shibata, Tomohiro; Pelton, Matthew; Shevchenko, Elena V
2018-04-19
Colloidal semiconductor nanocrystals are commonly grown with a shell of a second semiconductor material to obtain desired physical properties, such as increased photoluminescence quantum yield. However, the growth of a lattice-mismatched shell results in strain within the nanocrystal, and this strain has the potential to produce crystalline defects. Here, we study CdSe/CdS core/shell nanorods as a model system to investigate the influence of core size and shape on the formation of stacking faults in the nanocrystal. Using a combination of high-angle annular dark-field scanning transmission electron microscopy and pair-distribution-function analysis of synchrotron X-ray scattering, we show that growth of the CdS shell on smaller, spherical CdSe cores results in relatively small strain and few stacking faults. By contrast, growth of the shell on larger, prolate spheroidal cores leads to significant strain in the CdS lattice, resulting in a high density of stacking faults.
Ahn, Yumi; Jeong, Youngjun; Lee, Donghwa; Lee, Youngu
2015-03-24
A copper nanowire-graphene (CuNW-G) core-shell nanostructure was successfully synthesized using a low-temperature plasma-enhanced chemical vapor deposition process at temperatures as low as 400 °C for the first time. The CuNW-G core-shell nanostructure was systematically characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman, and X-ray photoelectron spectroscopy measurements. A transparent conducting electrode (TCE) based on the CuNW-G core-shell nanostructure exhibited excellent optical and electrical properties compared to a conventional indium tin oxide TCE. Moreover, it showed remarkable thermal oxidation and chemical stability because of the tight encapsulation of the CuNW with gas-impermeable graphene shells. The potential suitability of CuNW-G TCE was demonstrated by fabricating bulk heterojunction polymer solar cells. We anticipate that the CuNW-G core-shell nanostructure can be used as an alternative to conventional TCE materials for emerging optoelectronic devices such as flexible solar cells, displays, and touch panels.
Replication of Annual Cycles in Mn in Hudson River Cores: Mn Peaks During High Water Flow
NASA Astrophysics Data System (ADS)
Abbott, D. H.; Hutson, D.; Marrero, A. M.; Block, K. A.; Chang, C.; Cai, Y.
2017-12-01
Using the results from an ITRAX, XRF scanner, we previously reported apparent annual cycles in Mn in a single, high sedimentation rate Hudson River core, LWB1-8, taken off Yonkers, NY (Carlson et al., 2016). We replicated these results in three more high sedimentation rate cores and found stratigraphic markers that verify our inferences about the annual nature of the Mn cycles. The three new cores are LWB4-5 taken off Peekskill, NY, and LWB3-44 and LWB3-25, both taken in Haverstraw Bay. The cores are from water depths of 7-9 meters and all have high magnetic susceptibilities (typically > 30 cgs units) in their upper 1 to 2 meters. The high susceptibilities are primarily produced by magnetite from modern industrial combustion. One core, LWB1-8, has reconnaissance Cs dates that verify the annual nature of the cycles. More Cs dates are expected before the meeting. We developed several new methods of verifying the annual nature of our layer counts. The first is looking at the grain size distribution and age of layers with unusually high Mn peaks. Peaks in Si, Ni and Ti and peaks in percentage of coarse material typically accompany the peaks in Mn. Some are visible as yellow sandy layers. The five highest peaks in Mn in LWB1-8 have layer counted ages that correspond (within 1 year in the top meter and within 2 years in the bottom meter) to 1996, 1948, 1913, 1857 and 1790. The latter three events are the three largest historical spring freshets on the Hudson. 1996 is a year of unusually high flow rate during the spring freshet. Based on our work and previous work on Mn cycling in rivers, we infer that the peaks in Mn are produced by extreme erosional events that erode sediment and release pore water Mn into the water column. The other methods of testing our chronology involve marine storms that increase Ca and Sr and a search for fragments of the Peekskill meteorite that fell in October 1992. More information on the latter will be available by the meeting.
... thyroid; Radioactive iodine uptake and scan test - thyroid; Nuclear scan - thyroid ... the test. Ask your provider or the radiology/nuclear medicine team performing the scan about taking precautions.
Isotopically Heavy Low-Spin Iron in Ferropericlase at the Core-Mantle Boundary
NASA Astrophysics Data System (ADS)
Yang, H.; Lin, J. F.; Dauphas, N.; Bi, W.; Zhao, J.
2016-12-01
The iron isotope fractionation between metal and silicate at high pressure is of great interest for it is potentially responsible for the iron isotopic difference between the 2 main iron reservoir —the mantle and the core and therefore vital for estimating the bulk iron isotopic composition of the Earth. In 2009, Polyakov pioneered the use of NRIXS(Nuclear Resonant Inelastic X-ray Scat- tering) technique to investigate iron isotope fractionation at core-mantle boundary. This synchr- otron-based technique is excellent in that it can be applied to samples loaded in DACs with tens of um in size and one doesn't needs to put minerals together to reach isotope exchange equilib- rium. However, the NRIXS data used in Polyakov(2009) was scanned over a limited energy range and thus is not suitable for isotope fractionation at high pressure: the phonon modes shift with increasing pressure and a scanned energy range over 100meV is necessary. Recently, Shahar and co-workers(2016) used NRIXS with a wider energy scan range and DFT simulation to estimate the light element alloying effect on iron bonding environment at high pressure. They found that C or H may not be a major light element in the core considering only bridgmanite as a proxy of the mantle, but another lower mantle mineral ferropericlase was not taken into account. Here we report newly collected NRIXS data at sector-3 of the Advanced Photon Source. >95% 57Fe enriched powder ferropericlase((Fe0.25,Mg0.75)O) was loaded in 3-fold panoramic DACs us- ing Be gasket and c-BN insert as windows for X-ray fluorescence. The NRIXS spectra of ferroperic- lase were measured up to 94GPa across the spin transition zone. We found that the spin state of iron dramatically influences its force constants at high pressure. Low-spin iron force constants incr- ease 3 times faster than high-spin iron with pressure. Assuming linear relationship between force constants and pressure, this will lead to a fractionation of 0.147 (delta57Fe/54Fe
Honeker, Linnea K; Root, Robert A; Chorover, Jon; Maier, Raina M
2016-12-01
Metal(loid)-contamination of the environment due to anthropogenic activities is a global problem. Understanding the fate of contaminants requires elucidation of biotic and abiotic factors that influence metal(loid) speciation from molecular to field scales. Improved methods are needed to assess micro-scale processes, such as those occurring at biogeochemical interfaces between plant tissues, microbial cells, and metal(loid)s. Here we present an advanced method that combines fluorescence in situ hybridization (FISH) with synchrotron-based multiple-energy micro-focused X-ray fluorescence microprobe imaging (ME μXRF) to examine colocalization of bacteria and metal(loid)s on root surfaces of plants used to phytostabilize metalliferous mine tailings. Bacteria were visualized on a small root section using SytoBC nucleic acid stain and FISH probes targeting the domain Bacteria and a specific group (Alphaproteobacteria, Gammaproteobacteria, or Actinobacteria). The same root region was then analyzed for elemental distribution and metal(loid) speciation of As and Fe using ME μXRF. The FISH and ME μXRF images were aligned using ImageJ software to correlate microbiological and geochemical results. Results from quantitative analysis of colocalization show a significantly higher fraction of As colocalized with Fe-oxide plaques on the root surfaces (fraction of overlap 0.49±0.19) than to bacteria (0.072±0.052) (p<0.05). Of the bacteria that colocalized with metal(loid)s, Actinobacteria, known for their metal tolerance, had a higher correlation with both As and Fe than Alphaproteobacteria or Gammaproteobacteria. This method demonstrates how coupling these micro-techniques can expand our understanding of micro-scale interactions between roots, metal(loid)s and microbes, information that should lead to improved mechanistic models of metal(loid) speciation and fate. Copyright © 2016 Elsevier B.V. All rights reserved.
Stair-rod dislocation cores acting as one-dimensional charge channels in GaAs nanowires
NASA Astrophysics Data System (ADS)
Bologna, Nicolas; Agrawal, Piyush; Campanini, Marco; Knödler, Moritz; Rossell, Marta D.; Erni, Rolf; Passerone, Daniele
2018-01-01
Aberration-corrected scanning transmission electron microscopy and density-functional theory calculations have been used to investigate the atomic and electronic structure of stair-rod dislocations connected via stacking faults in GaAs nanowires. At the apexes, two distinct dislocation cores consisting of single-column pairs of either gallium or arsenic were identified. Ab initio calculations reveal an overall reduction in the energy gap with the development of two bands of filled and empty localized states at the edges of valence and conduction bands in the Ga core and in the As core, respectively. Our results suggest the behavior of stair-rod dislocations along the nanowire as one-dimensional charge channels, which could host free carriers upon appropriate doping.
Shah, Manthan P; Shendell, Derek G; Meng, Qingyu; Ohman-Strickland, Pamela; Halperin, William
2018-04-23
The performances of a portable X-Ray Fluorescence (XRF) lead paint analyzer (RMD LPA-1, Protec Instrument Corp., Waltham, MA) and a commercially available colorimetric lead test kit (First Alert Lead Test Kit, eAccess Solutions, Inc., Palatine, IL) were evaluated for use by local or state health departments as potential cost-effective rapid analysis or "spot test" field techniques for tentative identification of lead content in sindoor powders. For both field-sampling methods, sensitivity, specificity and predictive values varied widely for samples containing <300,000 μg/g lead. For samples containing ≥300,000 μg/g lead, the aforementioned metrics were 100% (however, the CIs had a wide range). In addition, both field sampling methods showed clear, consistent positive readings only for samples containing ≥300,000 μg/g lead. Even samples with lead content as high as 5,110 μg/g were not positively identified by either field analysis technique. The results of this study suggest the XRF analyzer and colorimetric lead test kit cannot be used as a rapid field test for sindoor by health department inspectors.
An interchangeable scanning Hall probe/scanning SQUID microscope
DOE Office of Scientific and Technical Information (OSTI.GOV)
Tang, Chiu-Chun; Lin, Hui-Ting; Wu, Sing-Lin
2014-08-15
We have constructed a scanning probe microscope for magnetic imaging, which can function as a scanning Hall probe microscope (SHPM) and as a scanning SQUID microscope (SSM). The scanning scheme, applicable to SHPM and SSM, consists of a mechanical positioning (sub) micron-XY stage and a flexible direct contact to the sample without a feedback control system for the Z-axis. With the interchangeable capability of operating two distinct scanning modes, our microscope can incorporate the advantageous functionalities of the SHPM and SSM with large scan range up to millimeter, high spatial resolution (⩽4 μm), and high field sensitivity in a widemore » range of temperature (4.2 K-300 K) and magnetic field (10{sup −7} T-1 T). To demonstrate the capabilities of the system, we present magnetic images scanned with SHPM and SSM, including a RbFeB magnet and a nickel grid pattern at room temperature, surface magnetic domain structures of a La{sub 2/3}Ca{sub 1/3}MnO{sub 3} thin film at 77 K, and superconducting vortices in a striped niobium film at 4.2 K.« less
Fabrication of polyacrylate core-shell nanoparticles via spray drying method
NASA Astrophysics Data System (ADS)
Chen, Pengpeng; Cheng, Zenghui; Chu, Fuxiang; Xu, Yuzhi; Wang, Chunpeng
2016-05-01
Fine polyacrylate particles are thought to be environmental plastisols for car industry. However, these particles are mainly dried through demulsification of the latexes, which is not reproducible and hard to be scaled up. In this work, a spray drying method had been applied to the plastisols-used acrylate latex. By adjusting the core/shell ratio, spray drying process of the latex was fully studied. Scanning electronic microscopy observation of the nanoparticles before and after spray drying indicated that the core-shell structures could be well preserved and particles were well separated by spray drying if the shell was thick enough. Otherwise, the particles fused into each other and core-shell structures were destroyed. Polyacrylate plastisols were developed using diisononylphthalate as a plasticizer, and plastigels were obtained after heat treatment of the sols. Results showed that the shell thickness also had a great influence on the storage stability of the plastisols and mechanical properties of the plastigels.
NASA Astrophysics Data System (ADS)
Gullu, Bahattin; Kadioglu, Yusuf Kagan
2017-08-01
Tourmaline defines a group of complex borosilicate forms as accessory mineral in igneous and metamorphic rocks and they act an important role in the interpretation of the chemical composition changes of the composition of the host fluid of the magma. The variety of tourmaline can be identified by using optical microscopy, X-Ray Diffraction (XRD) and by determining its chemical composition through Polarized Energy Dispersive X-Ray Fluorescence (PED-XRF) methods. However, microscopic investigations and XRD analyses are not quite adequate for detailed determination of tourmaline sub-groups. In addition, the use of chemical composition of tourmaline as a strict indicator of geochemical processes might be a misleading method. In this study, variable tourmaline crystals were collected from three different pegmatitic occurrences in Behrekdag, Yozgat and Karakaya granitic bodies of Central Anatolia to identify their chemical properties through Confocal Raman Spectroscopy (CRS), PED-XRF and XRD analyses. The confocal Raman spectrometry of collected tourmalines from the Behrekdag, Yozgat and Karakaya granites are in the compositions of schorl, schorl and elbaite respectively. The dominant compositional groups of these tourmalines are in the form of schorl. Raman shift values of tourmalines revealed four bands centered at almost 1050, 750, 400 and 300 cm- 1. The first group of the band arises from SiO stretching, the second from Bsbnd O stretching and the other two belong to bending modes of Osbnd Bsbnd O and Bsbnd Osbnd Al with symmetrical deformation of Sisbnd Osbnd Si. The strongest spectra near 360 cm- 1 should belong to the bonding of Alsbnd O. As a result, the confocal Raman studies are more sensitive for identification of tourmaline subgroup compositions and have a quite important in the explaining source of the magma.
Gullu, Bahattin; Kadioglu, Yusuf Kagan
2017-08-05
Tourmaline defines a group of complex borosilicate forms as accessory mineral in igneous and metamorphic rocks and they act an important role in the interpretation of the chemical composition changes of the composition of the host fluid of the magma. The variety of tourmaline can be identified by using optical microscopy, X-Ray Diffraction (XRD) and by determining its chemical composition through Polarized Energy Dispersive X-Ray Fluorescence (PED-XRF) methods. However, microscopic investigations and XRD analyses are not quite adequate for detailed determination of tourmaline sub-groups. In addition, the use of chemical composition of tourmaline as a strict indicator of geochemical processes might be a misleading method. In this study, variable tourmaline crystals were collected from three different pegmatitic occurrences in Behrekdag, Yozgat and Karakaya granitic bodies of Central Anatolia to identify their chemical properties through Confocal Raman Spectroscopy (CRS), PED-XRF and XRD analyses. The confocal Raman spectrometry of collected tourmalines from the Behrekdag, Yozgat and Karakaya granites are in the compositions of schorl, schorl and elbaite respectively. The dominant compositional groups of these tourmalines are in the form of schorl. Raman shift values of tourmalines revealed four bands centered at almost 1050, 750, 400 and 300cm -1 . The first group of the band arises from SiO stretching, the second from BO stretching and the other two belong to bending modes of OBO and BOAl with symmetrical deformation of SiOSi. The strongest spectra near 360cm -1 should belong to the bonding of AlO. As a result, the confocal Raman studies are more sensitive for identification of tourmaline subgroup compositions and have a quite important in the explaining source of the magma. Copyright © 2017 Elsevier B.V. All rights reserved.
NASA Technical Reports Server (NTRS)
Soderberg, A. M.; Nakar, E.; Cenko, S. B.; Cameron, P. B.; Frail, D. A.; Kulkarni, S. R.; Fox, D. B.; Berger, E.; Gal-Yam, A.; Moon, D-S.;
2007-01-01
We present detailed optical, near-infrared, and radio observations of the X-ray flash 050416a obtained with Palomar and Siding Springs Observatories as well as HST and the VLA, placing this event among the best-studied X-ray flashes to date. In addition, we present an optical spectrum from Keck LRIS from which we measure the redshift of the burst, Z=0.6528. At this redshift the isotropic-equivalent prompt energy release was about 10(exp 51) erg, and using a standard afterglow synchrotron model we find that the blastwave kinetic energy is a factor of 10 larger, E-K,iso approximately equals 10 (exp 52) erg. The lack of an observed jet break to t - 20 days indicates that the opening angle is larger than 7 deg and the total beaming-corrected relativistic energy is larger than 10 exp (50) erg. We further show that the burst produced a strong radio flare at t is similar to 40 days accompanied by an observed flattening in the X-ray band which we attribute to an abrupt circumburst density jump or an episode of energy injection (either from a refreshed shock or off-axis ejecta). Late-time observations with HST show evidence for an associated supernova with peak optical luminosity roughly comparable to that of SN 1998bw. Next, we show that the host galaxy of XRF 050416a is actively forming stars at a rate of at least 2 M-solar per year with a luminosity of L-B is similar to 0.5L* and metallicity of Z is similar to 0.2-0.8 Z-solar. Finally, we discuss the nature of XRF 050416a in the context of short-hard gamma-ray bursts and under the framework of off-axis and dirty fireball models for X-ray flashes.
CAT scan - leg; Computed axial tomography scan - leg; Computed tomography scan - leg; CT scan - leg ... CT scan makes detailed pictures of the body very quickly. The test may help look for: An abscess ...
CAT scan - arm; Computed axial tomography scan - arm; Computed tomography scan - arm; CT scan - arm ... Healing problems or scar tissue following surgery A CT scan may also be used to guide a surgeon ...
Nuclear scans use radioactive substances to see structures and functions inside your body. They use a special ... images. Most scans take 20 to 45 minutes. Nuclear scans can help doctors diagnose many conditions, including ...
Brain CT; Cranial CT; CT scan - skull; CT scan - head; CT scan - orbits; CT scan - sinuses; Computed tomography - cranial; CAT scan - brain ... conditions: Birth (congenital) defect of the head or brain Brain infection Brain tumor Buildup of fluid inside ...
An in situ FTIR step-scan photoacoustic investigation of kerogen and minerals in oil shale.
Alstadt, Kristin N; Katti, Dinesh R; Katti, Kalpana S
2012-04-01
Step-scan photoacoustic infrared spectroscopy experiments were performed on Green River oil shale samples obtained from the Piceance Basin located in Colorado, USA. We have investigated the molecular nature of light and dark colored areas of the oil shale core using FTIR photoacoustic step-scan spectroscopy. This technique provided us with the means to analyze the oil shale in its original in situ form with the kerogen-mineral interactions intact. All vibrational bands characteristic of kerogen were found in the dark and light colored oil shale samples confirming that kerogen is present throughout the depth of the core. Depth profiling experiments indicated that there are changes between layers in the oil shale molecular structure at a length scale of micron. Comparisons of spectra from the light and dark colored oil shale core samples suggest that the light colored regions have high kerogen content, with spectra similar to that from isolated kerogen, whereas, the dark colored areas contain more mineral components which include clay minerals, dolomite, calcite, and pyrite. The mineral components of the oil shale are important in understanding how the kerogen is "trapped" in the oil shale. Comparing in situ kerogen spectra with spectra from isolated kerogen indicate significant band shifts suggesting important nonbonded molecular interactions between the kerogen and minerals. Copyright © 2011 Elsevier B.V. All rights reserved.
Core-shell-structured nanothermites synthesized by atomic layer deposition
NASA Astrophysics Data System (ADS)
Qin, Lijun; Gong, Ting; Hao, Haixia; Wang, Keyong; Feng, Hao
2013-12-01
Thermite materials feature very exothermic solid-state redox reactions. However, the energy release rates of traditional thermite mixtures are limited by the reactant diffusion velocities. In this work, atomic layer deposition (ALD) is utilized to synthesize thermite materials with greatly enhanced reaction rates. By depositing certain types of metal oxides (oxidizers) onto a commercial Al nanopowder, core-shell-structured nanothermites can be produced. The average film deposition rate on the Al nanopowder is 0.17 nm/cycle for ZnO and 0.031 nm/cycle for SnO2. The thickness of the oxidizer layer can be precisely controlled by adjusting the ALD cycle number. The compositions, morphologies, and structures of the ALD nanothermites are characterized by X-ray photoelectron spectroscopy, scanning electron microscopy, and high-resolution transmission electron microscopy. The characterization results reveal nearly perfect coverage of the Al nanoparticles by uniform ALD oxidizer layers and confirm the formation of core-shell nanoparticles. Combustion properties of the nanothermites are probed by laser ignition technique. Reactions of the core-shell-structured nanothermites are several times faster than the mixture of nanopowders. The promoted reaction rate is mostly attributed to the uniform distribution of reactants on the nanometer scale. These core-shell-structured nanothermites provide a potential pathway to control and enhance thermite reactions.
The Native Form and Maturation Process of Hepatitis C Virus Core Protein
Yasui, Kohichiroh; Wakita, Takaji; Tsukiyama-Kohara, Kyoko; Funahashi, Shin-Ichi; Ichikawa, Masumi; Kajita, Tadahiro; Moradpour, Darius; Wands, Jack R.; Kohara, Michinori
1998-01-01
The maturation and subcellular localization of hepatitis C virus (HCV) core protein were investigated with both a vaccinia virus expression system and CHO cell lines stably transformed with HCV cDNA. Two HCV core proteins, with molecular sizes of 21 kDa (p21) and 23 kDa (p23), were identified. The C-terminal end of p23 is amino acid 191 of the HCV polyprotein, and p21 is produced as a result of processing between amino acids 174 and 191. The subcellular localization of the HCV core protein was examined by confocal laser scanning microscopy. Although HCV core protein resided predominantly in the cytoplasm, it was also found in the nucleus and had the same molecular size as p21 in both locations, as determined by subcellular fractionation. The HCV core proteins had different immunoreactivities to a panel of monoclonal antibodies. Antibody 5E3 stained core protein in both the cytoplasm and the nucleus, C7-50 stained core protein only in the cytoplasm, and 499S stained core protein only in the nucleus. These results clearly indicate that the p23 form of HCV core protein is processed to p21 in the cytoplasm and that the core protein in the nucleus has a higher-order structure different from that of p21 in the cytoplasm. HCV core protein in sera of patients with HCV infection was analyzed in order to determine the molecular size of genuinely processed HCV core protein. HCV core protein in sera was found to have exactly the same molecular weight as the p21 protein. These results suggest that p21 core protein is a component of native viral particles. PMID:9621068
NASA Astrophysics Data System (ADS)
Sfarra, Stefano; Ibarra-Castanedo, Clemente; Ridolfi, Stefano; Cerichelli, Giorgio; Ambrosini, Dario; Paoletti, Domenica; Maldague, Xavier
2014-06-01
Wood has been routinely employed in decorative arts, as well as in sculptures and paintings (support) during the Middle Ages, because of its unique aesthetic virtues. It may safely be assumed that wood, as a material for monumental sculpture, was much more commonly employed in the mediaeval period than existing examples would seem to indicate (Bulletin of the metropolitan Museum of Art,
NASA Astrophysics Data System (ADS)
Bohaty, Steven M.; Huck, Claire E.; Liebrand, Diederik; Röhl, Ursula; Wilson, Paul; van de Flierdt, Tina; Pälike, Heiko
2016-04-01
The early stages of the modern 'Icehouse' climate state first developed in the Oligocene following rapid global cooling and the onset of Antarctic glaciation at the Eocene-Oligocene Transition (34 Ma). However, the size and stability of the early Antarctic ice sheets that existed during the Oligocene under atmospheric CO2 levels higher than present day are poorly known. Here we report on an ongoing investigation of Oligocene (hemi)pelagic drillcores recovered at Ocean Drilling Program (ODP) Site 689, drilled on Maud Rise in the eastern Weddell Sea in late 1980s (Leg 113). Shipboard physical properties data were not routinely collected from pre-Quaternary cores at this site, and the lack of continuous composite sections and supporting data has previously been a considerable hindrance to high-resolution paleoceanographic studies. New high-resolution XRF scanning, discrete magnetic susceptibility, and benthic foraminiferal stable isotope records were collected from the upper Eocene-upper Oligocene interval of ODP Sites 689. The XRF datasets allow compositing of Holes 689B and 689D, which fortuitously contain offset cores throughout the sequence. Although condensed in two intervals, Site 689 contains a complete ~12-Myr record spanning Chron C17n.1n to Chron C8n.1n (~37 to 25 Ma). The composited records from Sites 689 exhibit prominent orbital-scale cyclicity in XRF-derived iron/calcium ratios, enabling development of an astronomical age model and detailed reconstruction of carbonate dissolution intensity of South Atlantic deep waters. These composited and well-dated records from Site 689 will, for the first-time, provide an Oligocene pelagic reference section for the Southern Ocean and serve as stratigraphic stepping stone between proximal Antarctic shelf records and high-resolution proxy records from lower latitude locations. Further development of high-resolution benthic foraminiferal and detrital neodymium isotope records at Site 689 will address the timing and
Ultrafast light matter interaction in CdSe/ZnS core-shell quantum dots
NASA Astrophysics Data System (ADS)
Yadav, Rajesh Kumar; Sharma, Rituraj; Mondal, Anirban; Adarsh, K. V.
2018-04-01
Core-shell quantum dot are imperative for carrier (electron and holes) confinement in core/shell, which provides a stage to explore the linear and nonlinear optical phenomena at the nanoscalelimit. Here we present a comprehensive study of ultrafast excitation dynamics and nonlinear optical absorption of CdSe/ZnS core shell quantum dot with the help of ultrafast spectroscopy. Pump-probe and time-resolved measurements revealed the drop of trapping at CdSe surface due to the presence of the ZnS shell, which makes more efficient photoluminescence. We have carried out femtosecond transient absorption studies of the CdSe/ZnS core-shell quantum dot by irradiation with 400 nm laser light, monitoring the transients in the visible region. The optical nonlinearity of the core-shell quantum dot studied by using the Z-scan technique with 120 fs pulses at the wavelengths of 800 nm. The value of two photon absorption coefficients (β) of core-shell QDs extracted as80cm/GW, and it shows excellent benchmark for the optical limiting onset of 2.5GW/cm2 with the low limiting differential transmittance of 0.10, that is an order of magnitude better than graphene based materials.
WWER-1000 core and reflector parameters investigation in the LR-0 reactor
DOE Office of Scientific and Technical Information (OSTI.GOV)
Zaritsky, S. M.; Alekseev, N. I.; Bolshagin, S. N.
2006-07-01
Measurements and calculations carried out in the core and reflector of WWER-1000 mock-up are discussed: - the determination of the pin-to-pin power distribution in the core by means of gamma-scanning of fuel pins and pin-to-pin calculations with Monte Carlo code MCU-REA and diffusion codes MOBY-DICK (with WIMS-D4 cell constants preparation) and RADAR - the fast neutron spectra measurements by proton recoil method inside the experimental channel in the core and inside the channel in the baffle, and corresponding calculations in P{sub 3}S{sub 8} approximation of discrete ordinates method with code DORT and BUGLE-96 library - the neutron spectra evaluations (adjustment)more » in the same channels in energy region 0.5 eV-18 MeV based on the activation and solid state track detectors measurements. (authors)« less
Nonlinear optical properties of metal alkanoate composites with hybrid core/shell nanoparticles
NASA Astrophysics Data System (ADS)
Rudenko, V.; Tolochko, A.; Zhulai, D.; Klimusheva, G.; Mirnaya, T.; Yaremchuk, G.; Asaula, V.
2018-02-01
New composites with hybrid CdSe/ZnS and Au/CdSe nanoparticles (NPs) were chemically synthesized in the thermotropic liquid crystalline phase (smectic A) of cadmium octanoate. Features of structure and nonlinear optical properties of glassy cadmium octanoate composites with hybrid core/shell NPs were studied using small-angle X-ray scattering method and Z-scan technique. Experimental optical setup (Z-scan) is based on a Nd: YAG laser, generating 9 ns pulses with a repetition rate of 0,5 Hz on a wavelength of 532 nm. The effects of the influence of hybrid NPs on the nonlinear optical properties of nanocomposites are considered in this study.
Barhoum, Erek; Johnston, Richard; Seibel, Eric
2005-09-19
An optical model of an ultrathin scanning fiber endoscope was constructed using a non-sequential ray tracing program and used to study the relationship between fiber deflection and collection efficiency from tissue. The problem of low collection efficiency of confocal detection through the scanned single-mode optical fiber was compared to non-confocal cladding detection. Collection efficiency is 40x greater in the non-confocal versus the confocal geometry due to the majority of rays incident on the core being outside the numerical aperture. Across scan angles of 0 to 30o, collection efficiency decreases from 14.4% to 6.3% for the non-confocal design compared to 0.34% to 0.10% for the confocal design. Non-confocality provides higher and more uniform collection efficiencies at larger scan angles while sacrificing the confocal spatial filter.
NASA Astrophysics Data System (ADS)
Wang, Y.; Hendy, I. L.; Thunell, R.
2017-12-01
The short duration of instrumental records limits our understanding of nitrogen loss to denitrification on interannual to centennial time scales. Bulk sediment δ15N is widely applied as a proxy for water column denitrification in oxygen minimum zones (OMZ). Lying within the California OMZ, Santa Barbara Basin (SBB) provides an ideal location for producing a high-resolution δ15N record for denitrification reconstruction. Here we present a high-resolution ( 1-2 y) 2000-year record of δ15N from SPR0901-03KC (34°16.99'N, 120°2.408'W; 586 m depth). Grey flood layer sediments are associated with abrupt decreases of 0.9 to 2.5 ‰ in the δ15N record. After removal of flood-affected samples from the record, δ15N varies from 6.8 to 8.7 ‰ with an average of 7.7 ‰. After 1800 AD δ15N experienced a sustained decrease to its minimum at the core top. Comparison with the principal components (PCs) of scanning X-ray fluorescence (XRF) elemental counts allow for further investigation of factors driving δ15N variations. The first PC (PC1) of scanning XRF elemental records contains high loadings for lithogenic sediment components while the second PC (PC2) has high loadings for biogenic components. The δ15N record is positively correlated with PC2 (r=0.2521, p<0.01) throughout the core while negatively correlated with PC1 relationship (r=-0.2596, p<0.01) between AD 1000-1800. Peaks of δ15N and PC2 (high primary productivity) coincide with intensified upwelling intervals supported by high anchovy scale counts, and bloom-forming diatoms (Rhizosolenia spp.) and silicoflagellates (D. speculum) from a nearby core. These upwelling intervals coincide with low PC1 (low river runoff). The coherent variability appears to indicate an atmospheric influence on the marine environment through the relative intensity of North Pacific High (NPH). Enhanced NPH induces stronger coastal upwelling with associated upward advection of δ15N-enriched subsurface water and higher primary
NASA Astrophysics Data System (ADS)
Billè, Fulvio; Kourousias, George; Luchinat, Enrico; Kiskinova, Maya; Gianoncelli, Alessandra
2016-08-01
XRF spectroscopy is among the most widely used non-destructive techniques for elemental analysis. Despite the known angular dependence of X-ray fluorescence (XRF), topological artefacts remain an unresolved issue when using X-ray micro- or nano-probes. In this work we investigate the origin of the artefacts in XRF imaging of topologically complex samples, which are unresolved problems in studies of organic matter due to the limited travel distances of low energy XRF emission from the light elements. In particular we mapped Human Embryonic Kidney (HEK293T) cells. The exemplary results with biological samples, obtained with a soft X-ray scanning microscope installed at a synchrotron facility were used for testing a mathematical model based on detector response simulations, and for proposing an artefact correction method based on directional derivatives. Despite the peculiar and specific application, the methodology can be easily extended to hard X-rays and to set-ups with multi-array detector systems when the dimensions of surface reliefs are in the order of the probing beam size.
Multielement mapping of alpha-SiC by scanning Auger microscopy
NASA Technical Reports Server (NTRS)
Browning, Ray; Smialek, James L.; Jacobson, Nathan S.
1987-01-01
Fine second-phase particles, numerous in sintered alpha-SiC, were analyzed by scanning Auger microscopy and conventional techniques. The Auger analysis utilized computer-controlled data acquisition, multielement correlation diagrams, and a high spatial resolution of 100 nm. This procedure enabled construction of false color maps and the detection of fine compositional details within these particles. Carbon, silicon oxide, and boron-rich particles (qualitatively as BN or B4C) predominated. The BN particles, sometimes having a carbon core, are believed to result from reaction between B4C additives and nitrogen sintering atmospheres.
Detailed Investigation of Core-Shell Precipitates in a Cu-Containing High Entropy Alloy
NASA Astrophysics Data System (ADS)
Alam, T.; Gwalani, B.; Viswanathan, G.; Fraser, H.; Banerjee, R.
2018-05-01
Due to the competing influences of configurational entropy and enthalpy of mixing, in recent years, secondary (including intermetallic) phases have been reported in many high entropy alloy (HEA) systems. These secondary phases offer great potential in terms of strengthening the HEA beyond the solid solution strengthening effects, and as such are of great interest in regards to alloy design for engineering applications. The present research investigates novel nano-scale core-shell precipitates forming within the disordered bcc matrix phase of an Al2CrCuFeNi2 HEA, utilizing complementary high-resolution microscopy techniques of atom probe tomography (APT) and transmission electron microscopy (TEM). The size, morphology, and local chemistry of these core-shell precipitates was measured by APT, and the composition was further corroborated by high-resolution scanning transmission electron microscopy-energy dispersive spectroscopy in an aberration-corrected TEM. Furthermore, high-resolution TEM imaging of the core-shell structure indicates that the Cu-rich core exhibits a bcc crystal structure.
Tropical cyclone warm core analyses with FY-3 microwave temperature sounder data
NASA Astrophysics Data System (ADS)
Liu, Zhe; Bai, Jie; Zhang, Wenjun; Yan, Jun; Zhou, Zhuhua
2014-05-01
Space-borne microwave instruments are well suited to analyze Tropical Cyclone (TC) warm core structure, because certain wavelengths of microwave energy are able to penetrate the cirrus above TC. With the vector discrete-ordinate microwave radiative transfer model, the basic atmospheric parameters of Hurricane BOB are used to simulate the upwelling brightness temperatures on each channel of the Microwave Temperature Sounder (MWTS) onboard FY-3A/3B observation. Based on the simulation, the characteristic of 1109 super typhoon "Muifa" warm core structure is analyzed with the MWTS channel 3. Through the radiative and hydrostatic equation, TC warm core brightness temperature anomalies are related to surface pressure anomalies. In order to correct the radiation attenuation caused by MWTS scan geometric features, and improve the capability in capturing the relatively complete warm core radiation, a proposed algorithm is devised to correct the bias from receiving warm core microwave radiation, shows similar time-variant tendency with "Muifa" minimal sea level pressure as described by TC best track data. As the next generation of FY-3 satellite will be launched in 2012, this method will be further verified
Visualizing Iron Deposition in Multiple Sclerosis Cadaver Brains
DOE Office of Scientific and Technical Information (OSTI.GOV)
Habib, Charbel A.; Zheng Weili; Mark Haacke, E.
Aim: To visualize and validate iron deposition in two cases of multiple sclerosis using rapid scanning X-Ray Fluorescence (RS-XRF) and Susceptibility Weighted Imaging (SWI). Material and Methods: Two (2) coronal cadaver brain slices from patients clinically diagnosed with multiple sclerosis underwent magnetic resonance imaging (MRI), specifically SWI to image iron content. To confirm the presence of iron deposits and the absence of zinc-rich myelin in lesions, iron and zinc were mapped using RS-XRF. Results: MS lesions were visualized using FLAIR and correlated with the absence of zinc by XRF. XRF and SWI showed that in the first MS case, theremore » were large iron deposits proximal to the draining vein of the caudate nucleus as well as iron deposits associated with blood vessels throughout the globus pallidus. Less iron was seen in association with lesions than in the basal ganglia. The presence of larger amounts of iron correlated reasonably well between RS-XRF and SWI. In the second case, the basal ganglia appeared normal and acute perivascular iron deposition was absent. Conclusion: Perivascular iron deposition is seen in some but not all MS cases, giving credence to the use of SWI to assess iron involvement in MS pathology in vivo.« less
Visualizing Iron Deposition in Multiple Sclerosis Cadaver Brains
DOE Office of Scientific and Technical Information (OSTI.GOV)
Habib, A.C.; Zheng, W.; Haacke, E.M.
To visualize and validate iron deposition in two cases of multiple sclerosis using rapid scanning X-Ray Fluorescence (RS-XRF) and Susceptibility Weighted Imaging (SWI). Two (2) coronal cadaver brain slices from patients clinically diagnosed with multiple sclerosis underwent magnetic resonance imaging (MRI), specifically SWI to image iron content. To confirm the presence of iron deposits and the absence of zinc-rich myelin in lesions, iron and zinc were mapped using RS-XRF. MS lesions were visualized using FLAIR and correlated with the absence of zinc by XRF. XRF and SWI showed that in the first MS case, there were large iron deposits proximalmore » to the draining vein of the caudate nucleus as well as iron deposits associated with blood vessels throughout the globus pallidus. Less iron was seen in association with lesions than in the basal ganglia. The presence of larger amounts of iron correlated reasonably well between RS-XRF and SWI. In the second case, the basal ganglia appeared normal and acute perivascular iron deposition was absent. Perivascular iron deposition is seen in some but not all MS cases, giving credence to the use of SWI to assess iron involvement in MS pathology in vivo.« less
Visualizing Iron Deposition in Multiple Sclerosis Cadaver Brains
NASA Astrophysics Data System (ADS)
Habib, Charbel A.; Zheng, Weili; Mark Haacke, E.; Webb, Sam; Nichol, Helen
2010-07-01
Aim: To visualize and validate iron deposition in two cases of multiple sclerosis using rapid scanning X-Ray Fluorescence (RS-XRF) and Susceptibility Weighted Imaging (SWI). Material and Methods: Two (2) coronal cadaver brain slices from patients clinically diagnosed with multiple sclerosis underwent magnetic resonance imaging (MRI), specifically SWI to image iron content. To confirm the presence of iron deposits and the absence of zinc-rich myelin in lesions, iron and zinc were mapped using RS-XRF. Results: MS lesions were visualized using FLAIR and correlated with the absence of zinc by XRF. XRF and SWI showed that in the first MS case, there were large iron deposits proximal to the draining vein of the caudate nucleus as well as iron deposits associated with blood vessels throughout the globus pallidus. Less iron was seen in association with lesions than in the basal ganglia. The presence of larger amounts of iron correlated reasonably well between RS-XRF and SWI. In the second case, the basal ganglia appeared normal and acute perivascular iron deposition was absent. Conclusion: Perivascular iron deposition is seen in some but not all MS cases, giving credence to the use of SWI to assess iron involvement in MS pathology in vivo.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Lee, Hee Uk; Song, Yoon Seok; Park, Chulhwan
2012-12-15
Graphical abstract: Display Omitted Highlights: ► A simple method was developed to synthesize Co-B/SiO{sub 2}/dye/SiO{sub 2} composite particles. ► The magnetic particle shows that highly luminescent and core/shell particles are formed. ► Such core/shell particles can be easily suspended in water. ► The magnetic particles could detect fluorescence for the application of biosensor. -- Abstract: A simple and reproducible method was developed to synthesize a novel class of Co-B/SiO{sub 2}/dye/SiO{sub 2} composite core/shell particles. Using a single cobalt core, Rhodamine 6G of organic dye molecules was entrapped in a silica shell, resulting in core/shell particles of ∼200 nm diameter. Analysesmore » using a variety of techniques such as transmission electron microscopy, X-ray photoelectron spectroscopy, vibration sample magnetometry, confocal laser scanning microscopy, and fluorescence intensity demonstrated that dye molecules were trapped inside the core/shell particles. A photoluminescence investigation showed that highly luminescent and photostable core/shell particles were formed. Such core/shell particles can be easily suspended in water. The synthesized magnetic particles could be used to detect fluorescence on glass substrate arrays for bioassay and biosensor applications.« less
Yu, Meiling; Yao, Qing; Zhang, Yan; Chen, Huilin; He, Haibing; Zhang, Yu; Yin, Tian; Tang, Xing; Xu, Hui
2018-02-27
Highly soluble drugs tend to release from preparations at high speeds, which make them need to be taken at frequent intervals. Additionally, some drugs need to be controlled to release in vivo at certain periods, so as to achieve therapeutic effects. Thus, the objective of this study is to design injectable microparticulate systems with controllable in vivo release profile. Biodegradable PLGA was used as the matrix material to fabricate microspheres using the traditional double emulsification-solvent evaporation method as well as improved techniques, with gel (5% gelatine or 25% F127) or LP powders as the inner phases. Their physicochemical properties were systemically investigated. Microspheres prepared by modified methods had an increase in drug loading (15.50, 16.72, 15.66%, respectively) and encapsulation efficiencies (73.46, 79.42, 74.40%, respectively) when compared with traditional methods (12.01 and 57.06%). The morphology of the particles was characterized by optical microscope (OM) and scanning electron microscopy (SEM), and the amorphous nature of the encapsulated drug was confirmed by differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis. To evaluate their release behaviour, the in vitro degradation, in vitro release and in vivo pharmacodynamics were subsequently studied. Traditional microspheres prepared in this study with water as the inner phase had a relatively short release period within 16 d when compared with modified microspheres with 5% gelatine as the inner phase, which resulted in a smooth release profile and appropriate plasma LP concentrations over 21 d. Thus this type of modified microspheres can be better used in drugs requiring sustained release. The other two formulations containing 25% F127 and LP micropowders presented two-stage release profiles, resulting in fluctuant plasma LP concentrations which may be suitable for drugs requiring controlled release. All the results suggested that drug release rates from
NASA Astrophysics Data System (ADS)
Ghimpu, L.; Ursaki, V. V.; Pantazi, A.; Mesterca, R.; Brâncoveanu, O.; Shree, Sindu; Adelung, R.; Tiginyanu, I. M.; Enachescu, M.
2018-04-01
We report the fabrication and characterization of SnO2/CdTe and SnO2/GaAs core/shell microstructures. CdTe or GaAs shell layers were deposited by radio-frequency (RF) magnetron sputtering on core SnO2 microwires synthesized by a flame-based thermal oxidation method. The produced structures were characterized by scanning electron microscopy (SEM), high-resolution scanning transmission electron microscope (HR-STEM), X-ray diffraction (XRD), Raman scattering and FTIR spectroscopy. It was found that the SnO2 core is of the rutile type, while the shells are composed of CdTe or GaAs nanocrystallites of zincblende structure with the dimensions of crystallites in the range of 10-20 nm. The Raman scattering investigations demonstrated that the quality of the porous nanostructured shell is improved by annealing at temperatures of 420-450 °C. The prospects of implementing these microstructures in intrinsic type fiber optic sensors are discussed.
NASA Astrophysics Data System (ADS)
Henares, S.; Bloemsma, M. R.; Donselaar, M. E.; Mijnlieff, H. F.; Redjosentono, A. E.; Veldkamp, H. G.; Weltje, G. J.
2014-12-01
The Rotliegend (Upper Permian) reservoir interval in the Southern Permian Basin (SPB) contains low-permeability streaks corresponding to anhydrite-cemented intervals. An integrated study was conducted using core, cuttings, thin sections and well-log data from a gas exploration well and two geothermal wells that target the zone of interest. This study aims at understanding the origin and nature of these low-permeability streaks, as well as their impact on reservoir properties, and to establish a predictive model of their spatial distribution. High-resolution XRF core-scanning analysis allowed to extrapolate spot observations in thin sections to the entire core. Diagenetic history includes grain rearrangement and anhydrite, haematitic clay coatings, dolomite rims, quartz overgrowths, kaolinite and second-generation carbonates as cementing phases. Coupling of all data reveals the detrital origin of the anhydrite/gypsum grains which were deposited together with the coarse-grained sand fraction in an aeolian sandflat environment. Such partially or completely dissolved grains acted as local sources of anhydrite cement and as nuclei for precipitation, explaining its preferential occurrence in coarse-grained laminae. Thick gypscretes in the vicinity likely supplied the anhydrite/gypsum grains. A conceptual model is proposed, including the location of nearby gypscretes and the prevailing west-southwest aeolian transport direction on the southern rim of the SPB.
Vertical Scan (V-SCAN) for 3-D Grid Adaptive Mesh Refinement for an atmospheric Model Dynamical Core
NASA Astrophysics Data System (ADS)
Andronova, N. G.; Vandenberg, D.; Oehmke, R.; Stout, Q. F.; Penner, J. E.
2009-12-01
One of the major building blocks of a rigorous representation of cloud evolution in global atmospheric models is a parallel adaptive grid MPI-based communication library (an Adaptive Blocks for Locally Cartesian Topologies library -- ABLCarT), which manages the block-structured data layout, handles ghost cell updates among neighboring blocks and splits a block as refinements occur. The library has several modules that provide a layer of abstraction for adaptive refinement: blocks, which contain individual cells of user data; shells - the global geometry for the problem, including a sphere, reduced sphere, and now a 3D sphere; a load balancer for placement of blocks onto processors; and a communication support layer which encapsulates all data movement. A major performance concern with adaptive mesh refinement is how to represent calculations that have need to be sequenced in a particular order in a direction, such as calculating integrals along a specific path (e.g. atmospheric pressure or geopotential in the vertical dimension). This concern is compounded if the blocks have varying levels of refinement, or are scattered across different processors, as can be the case in parallel computing. In this paper we describe an implementation in ABLCarT of a vertical scan operation, which allows computing along vertical paths in the correct order across blocks transparent to their resolution and processor location. We test this functionality on a 2D and a 3D advection problem, which tests the performance of the model’s dynamics (transport) and physics (sources and sinks) for different model resolutions needed for inclusion of cloud formation.
Core Hunter 3: flexible core subset selection.
De Beukelaer, Herman; Davenport, Guy F; Fack, Veerle
2018-05-31
Core collections provide genebank curators and plant breeders a way to reduce size of their collections and populations, while minimizing impact on genetic diversity and allele frequency. Many methods have been proposed to generate core collections, often using distance metrics to quantify the similarity of two accessions, based on genetic marker data or phenotypic traits. Core Hunter is a multi-purpose core subset selection tool that uses local search algorithms to generate subsets relying on one or more metrics, including several distance metrics and allelic richness. In version 3 of Core Hunter (CH3) we have incorporated two new, improved methods for summarizing distances to quantify diversity or representativeness of the core collection. A comparison of CH3 and Core Hunter 2 (CH2) showed that these new metrics can be effectively optimized with less complex algorithms, as compared to those used in CH2. CH3 is more effective at maximizing the improved diversity metric than CH2, still ensures a high average and minimum distance, and is faster for large datasets. Using CH3, a simple stochastic hill-climber is able to find highly diverse core collections, and the more advanced parallel tempering algorithm further increases the quality of the core and further reduces variability across independent samples. We also evaluate the ability of CH3 to simultaneously maximize diversity, and either representativeness or allelic richness, and compare the results with those of the GDOpt and SimEli methods. CH3 can sample equally representative cores as GDOpt, which was specifically designed for this purpose, and is able to construct cores that are simultaneously more diverse, and either are more representative or have higher allelic richness, than those obtained by SimEli. In version 3, Core Hunter has been updated to include two new core subset selection metrics that construct cores for representativeness or diversity, with improved performance. It combines and outperforms the
Core-shell silk hydrogels with spatially tuned conformations as drug-delivery system.
Yan, Le-Ping; Oliveira, Joaquim M; Oliveira, Ana L; Reis, Rui L
2017-11-01
Hydrogels of spatially controlled physicochemical properties are appealing platforms for tissue engineering and drug delivery. In this study, core-shell silk fibroin (SF) hydrogels of spatially controlled conformation were developed. The core-shell structure in the hydrogels was formed by means of soaking the preformed (enzymatically crosslinked) random coil SF hydrogels in methanol. When increasing the methanol treatment time from 1 to 10 min, the thickness of the shell layer can be tuned from about 200 to about 850 μm as measured in wet status. After lyophilization of the rehydrated core-shell hydrogels, the shell layer displayed compact morphology and the core layer presented porous structure, when observed by scanning electron microscopy. The conformation of the hydrogels was evaluated by Fourier transform infrared spectroscopy in wet status. The results revealed that the shell layer possessed dominant β-sheet conformation and the core layer maintained mainly random coil conformation. Enzymatic degradation data showed that the shell layers presented superior stability to the core layer. The mechanical analysis displayed that the compressive modulus of the core-shell hydrogels ranged from about 25 kPa to about 1.1 MPa by increasing the immersion time in methanol. When incorporated with albumin, the core-shell SF hydrogels demonstrated slower and more controllable release profiles compared with the non-treated hydrogel. These core-shell SF hydrogels of highly tuned properties are useful systems as drug-delivery system and may be applied as cartilage substitute. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.
NASA Astrophysics Data System (ADS)
Van Hoose, A. E.; Wolff, J.; Conrey, R.
2013-12-01
Advances in portable X-Ray fluorescence (pXRF) analytical technology have made it possible for high-quality, quantitative data to be collected in a fraction of the time required by standard, non-portable analytical techniques. Not only do these advances reduce analysis time, but data may also be collected in the field in conjunction with sampling. Rhyolitic pumice, being primarily glass, is an excellent material to be analyzed with this technology. High-quality, quantitative data for elements that are tracers of magmatic differentiation (e.g. Rb, Sr, Y, Nb) can be collected for whole, individual pumices and subsamples of larger pumices in 4 minutes. We have developed a calibration for powdered rhyolite pumice from the Otowi Member of the Bandelier Tuff analyzed with the Bruker Tracer IV pXRF using Bruker software and influence coefficients for pumice, which measures the following 19 oxides and elements: SiO2, TiO2, Al2O3, FeO*, MnO, CaO, K2O, P2O5, Zn, Ga, Rb, Sr, Y, Zr, Nb, Ba, Ce, Pb, and Th. With this calibration for the pXRF and thousands of individual powdered pumice samples, we have generated an unparalleled data set for any single eruptive unit with known trace element zonation. The Bandelier Tuff of the Valles-Toledo Caldera Complex, Jemez Mountains, New Mexico, is divided into three main eruptive events. For this study, we have chosen the 1.61 Ma, 450 km3 Otowi Member as it is primarily unwelded and pumice samples are easily accessible. The eruption began with a plinian phase from a single source located near center of the current caldera and deposited the Guaje Pumice Bed. The initial Unit A of the Guaje is geochemically monotonous, but Units B through E, co-deposited with ignimbrite show very strong chemical zonation in trace elements, progressing upwards through the deposits from highly differentiated compositions (Rb ~350 ppm, Nb ~200 ppm) to less differentiated (Rb ~100 ppm, Nb ~50 ppm). Co-erupted ignimbrites emplaced during column collapse show
Huang, Bing; Hao, Xiaofei; Zhang, Haobin; Yang, Zhijian; Ma, Zhigang; Li, Hongzhen; Nie, Fude; Huang, Hui
2014-07-01
To improve the safety of sensitive explosive HMX while maintaining explosion performance, a moderately powerful but insensitive explosive TATB was used to coat HMX microparticles via a facile ultrasonic method. By using Estane as surface modifier and nano-sized TATB as the shell layer, the HMX@TATB core-shell microparticles with a monodisperse size and compact shell structure were successfully constructed. Both scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) results confirmed the formation of perfect core-shell structured composites. Based on a systematic and comparative study of the effect of experimental conditions, a possible formation mechanism of core-shell structure was proposed in detail. Moreover, the perfect core-shell HMX@TATB microparticles exhibited a unique thermal behavior and significantly improved mechanical sensitivity compared with that of the physical mixture. Copyright © 2014 Elsevier B.V. All rights reserved.
NASA Astrophysics Data System (ADS)
Hasözbek, Altug; Shyam, Badri; Siebel, Wolfgang; Schmitt, Axel; Akay, Erhan; Skinner, Lawrie
2013-04-01
Zircon (ZrSiO4) is a mineral of singular importance in the geosciences. Zircon microanalysis has greatly contributed to our understanding of key events in earth's history as certain radioactive heavy elements and their daughter products are well-preserved within the exceptionally stable inorganic matrix of the mineral. A prevailing notion in this field is that zircon, as a mineral, is predominantly a crustal mineral; this has been contested in the last few years with more reports of mantle-derived zircons (Siebel et al., 2009). Zircons enriched from different parts of the upper mantle to lower crust from Turkey (Hasozbek et al. 2010) and Germany (Siebel et al., 2009) will be presented in this study using SR-XRF mapping carried out at beamline 2-IDE at the Advanced Photon Source synchrotron facility (Argonne National Laboratory, USA). The high-resolution (5-10 µm) elemental maps were obtained with collimated and linearly polarized synchrotron radiation (10 to 17 keV) and possess the advantage of being a completely non-destructive technique. Elemental maps of various trace and rare-earth elements along the cross-section of the zircons reveal a zonation-related distribution, which may be used to reveal factors affecting the growth history and dynamics of the crystal formation. Further, abrupt changes in elemental distribution or concentration were found to correspond to faults or inclusions within the zircon crystal. If such observations are found to be applicable for a wide range of samples, elemental mapping with this technique may serve as an important qualitative diagnostic to locating µ-meter inclusions that may be challenging to identify using other techniques (ICP-MS LA, SHRIMP,…) Through these preliminary elemental profile mapping studies of crustal and mantle zircons using SR-XRF methods, we aim to highlight a relatively quick and promising analytical method that may be used to study various geological problems.
NASA Astrophysics Data System (ADS)
Swaminathan, K.; Asokane, C.; Sylvia, J. I.; Kalyanasundaram, P.; Swaminathan, P.
2012-02-01
An ultrasonic under-sodium scanner has been developed for deployment in Prototype Fast Breeder Reactor (PFBR) which is in advanced stage of construction at Kalpakkam, India. Its purpose is to scan the above-core plenum for detection, if any, of displacement of sub-assemblies. During its burn-up in the reactor, the head of a Fuel Sub-Assembly (FSA) may undergo a lateral shift from its original position (called `bowing') due to the fast neutron induced damage on its structural material. A simple scanning technique has been developed for measuring the extent of bowing in-situ. This paper describes a PC-controlled mock-up of the scanner used to implement the scanning technique and the results obtained of scanning a mock-up FSA head under water. The details of the liquid-sodium proof transducer developed for use in the PFBR scanner and its performance are also discussed.
Effectiveness and usability of Scanning Wizard software: a tool for enhancing switch scanning.
Koester, Heidi Horstmann; Simpson, Richard C
2017-11-24
Scanning Wizard software helps scanning users improve the setup of their switch and scanning system. This study evaluated Scanning Wizard's effectiveness and usability. Ten people who use switch scanning and ten practitioners used Scanning Wizard in the initial session. Usability was high, based on survey responses averaging over 4.5 out of 5, and qualitative feedback was very positive. Five switch users were able to complete the multi-week protocol, using settings on their own scanning system that were recommended from the Scanning Wizard session. Using these revised settings, text entry rates improved by an average of 71%, ranging from 29% to 172% improvement. Results suggest that Scanning Wizard is a useful tool for improving the configuration of scanning systems for people who use switch scanning to communicate. Implications for Rehabilitation Some individuals with severe physical impairments use switch scanning for spoken and written communication. Scanning Wizard software helps scanning users improve the setup of their switch and scanning system. This study demonstrated high usability of Scanning Wizard (with 10 switch userpractitioner teams) and increased text entry rate by an average of 71% (for five switch users). Results suggest that Scanning Wizard is a useful tool for improving the configuration of scanning systems for people who use switch scanning to communicate.
Crystallization in Micellar Cores: confinement effects and dynamics
NASA Astrophysics Data System (ADS)
Lund, Reidar; Zinn, Thomas; Willner, Lutz; Department of Chemistry, University of Oslo Team; Forschungszentrum Jülich Collaboration
It is well known that liquids confined to small nanoscopic pores and droplets exhibit thermal behavior very different from bulk samples. Here we demonstrate that n-alkanes forming 2-3 nm small micellar cores are considerably affected by confinement in analogue with hard confined systems. We study micelles form by self-assembly of a series of well-defined n-Alkyl-PEO polymers in aqueous solutions. By using small-angle X-ray scattering (SAXS), densiometry and differential scanning calorimetry (DSC), we show that n-alkane exhibit a first-order phase transition i.e. melting. Correlating the structural and thermodynamic data, we find that a melting depression can be accurately described by the Gibbs-Thomson equation. ∖f1 The effect of core crystallinity on the molecular exchange kinetics is investigated using time-resolved small-angle neutron scattering (TR-SANS). We show that there are considerable entropic and enthalpic contributions from the chain packing that affect the kinetic stability of micelles. ∖pard
NASA Astrophysics Data System (ADS)
Li, Shunfeng; Wang, Xue; Fündling, Sönke; Erenburg, Milena; Ledig, Johannes; Wei, Jiandong; Wehmann, Hergo H.; Waag, Andreas; Bergbauer, Werner; Mandl, Martin; Strassburg, Martin; Trampert, Achim; Jahn, Uwe; Riechert, Henning; Jönen, Holger; Hangleiter, Andreas
2012-07-01
Homogeneous nitrogen-polar GaN core-shell light emitting diode (LED) arrays were fabricated by selective area growth on patterned substrates. Transmission electron microscopy measurements prove the core-shell structure of the rod LEDs. Depending on the growth facets, the InGaN/GaN multi-quantum wells (MQWs) show different dimensions and morphology. Cathodoluminescence (CL) measurements reveal a MQWs emission centered at about 415 nm on sidewalls and another emission at 460 nm from top surfaces. CL line scans on cleaved rod also indicate the core-shell morphology. Finally, an internal quantum efficiency of about 28% at room temperature was determined by an all-optical method on a LED array.
Birdwell, Justin E.; Lewan, Michael D.; Miller, Michael; Baez, Luis; Beeney, Ken; Sonnenberg, Steve
2013-01-01
A uniaxial confinement clamp was used on Woodford Shale cores in hydrous pyrolysis experiments to study fracture development during thermal maturation. The clamp simulates overburden in that it prevents cores from expanding perpendicular to bedding fabric during the volume-increasing reactions associated with petroleum generation. Cores were cut from a slab of immature Woodford Shale and subjected to hydrous pyrolysis under confinement at 300, 330, and 365 °C for 72 hours to induce thermal maturities ranging from early bitumen to maximum expelled-oil generation. Two additional cores were used as experimental controls: (1) a confined core was saturated with water by heating it to 100 °C under hydrous pyrolysis conditions for 72 hours to use for characterization of the original rock, and (2) an unconfined core was heated at 365 °C for 72 hours to evaluate the effects of confinement on petroleum generation and expulsion. X-ray computed tomography (X-CT) imaging and other analyses identified five distinct beds within the cored interval. Using a tentative classification system, beds 1, 2, and 3 are described as dolomitic marlstone (DM) with total organic carbon (TOC) contents of 7.7, 5.8, and 7.7 wt. %, respectively; bed 4 is a cherty quartzose claystone (CQC) with TOC content of 5.5 wt. %; and bed 5 is a quartzose claystone with TOC content of 10.9 wt. %. Bed samples all had similar Rock-Eval hydrogen indices (600 ± 46 mg S2/g-TOC) and Tmax values (433 ± 2 °C), demonstrating organic matter uniformity and low thermal maturity. The X-CT scan of the core heated to 100 °C showed preexisting fractures that were nearly perpendicular to the bedding fabric primarily in the low-TOC DM bed 2 and CQC bed 4. Heating led to enhancement of preexisting fractures in the confined cores with the greatest enhancement occurring in CQC bed 4. The fractures increased in size and intensity with temperature. This is attributed to the internal pressure generated by volume
Core-to-core uniformity improvement in multi-core fiber Bragg gratings
NASA Astrophysics Data System (ADS)
Lindley, Emma; Min, Seong-Sik; Leon-Saval, Sergio; Cvetojevic, Nick; Jovanovic, Nemanja; Bland-Hawthorn, Joss; Lawrence, Jon; Gris-Sanchez, Itandehui; Birks, Tim; Haynes, Roger; Haynes, Dionne
2014-07-01
Multi-core fiber Bragg gratings (MCFBGs) will be a valuable tool not only in communications but also various astronomical, sensing and industry applications. In this paper we address some of the technical challenges of fabricating effective multi-core gratings by simulating improvements to the writing method. These methods allow a system designed for inscribing single-core fibers to cope with MCFBG fabrication with only minor, passive changes to the writing process. Using a capillary tube that was polished on one side, the field entering the fiber was flattened which improved the coverage and uniformity of all cores.
Experimental Simulations of Methane Gas Migration through Water-Saturated Sediment Cores
NASA Astrophysics Data System (ADS)
Choi, J.; Seol, Y.; Rosenbaum, E. J.
2010-12-01
Previous numerical simulations (Jaines and Juanes, 2009) showed that modes of gas migration would mainly be determined by grain size; capillary invasion preferably occurring in coarse-grained sediments vs. fracturing dominantly in fine-grained sediments. This study was intended to experimentally simulate preferential modes of gas migration in various water-saturated sediment cores. The cores compacted in the laboratory include a silica sand core (mean size of 180 μm), a silica silt core (1.7 μm), and a kaolin clay core (1.0 μm). Methane gas was injected into the core placed within an x-ray-transparent pressure vessel, which was under continuous x-ray computed tomography (CT) scanning with controlled radial (σr), axial (σa), and pore pressures (P). The CT image analysis reveals that, under the radial effective stress (σr') of 0.69 MPa and the axial effective stress (σa') of 1.31 MPa, fracturings by methane gas injection occur in both silt and clay cores. Fracturing initiates at the capillary pressure (Pc) of ~ 0.41 MPa and ~ 2.41 MPa for silt and clay cores, respectively. Fracturing appears as irregular fracture-networks consisting of nearly invisibly-fine multiple fractures, longitudinally-oriented round tube-shape conduits, or fine fractures branching off from the large conduits. However, for the sand core, only capillary invasion was observed at or above 0.034 MPa of capillary pressure under the confining pressure condition of σr' = 1.38 MPa and σa' = 2.62 MPa. Compared to the numerical predictions under similar confining pressure conditions, fracturing occurs with relatively larger grain sizes, which may result from lower grain-contact compression and friction caused by loose compaction and flexible lateral boundary employed in the experiment.
Fast-Response Single-Nanowire Photodetector Based on ZnO/WS2 Core/Shell Heterostructures.
Butanovs, Edgars; Vlassov, Sergei; Kuzmin, Alexei; Piskunov, Sergei; Butikova, Jelena; Polyakov, Boris
2018-04-25
The surface plays an exceptionally important role in nanoscale materials, exerting a strong influence on their properties. Consequently, even a very thin coating can greatly improve the optoelectronic properties of nanostructures by modifying the light absorption and spatial distribution of charge carriers. To use these advantages, 1D/1D heterostructures of ZnO/WS 2 core/shell nanowires with a-few-layers-thick WS 2 shell were fabricated. These heterostructures were thoroughly characterized by scanning and transmission electron microscopy, X-ray diffraction, and Raman spectroscopy. Then, a single-nanowire photoresistive device was assembled by mechanically positioning ZnO/WS 2 core/shell nanowires onto gold electrodes inside a scanning electron microscope. The results show that a few layers of WS 2 significantly enhance the photosensitivity in the short wavelength range and drastically (almost 2 orders of magnitude) improve the photoresponse time of pure ZnO nanowires. The fast response time of ZnO/WS 2 core/shell nanowire was explained by electrons and holes sinking from ZnO nanowire into WS 2 shell, which serves as a charge carrier channel in the ZnO/WS 2 heterostructure. First-principles calculations suggest that the interface layer i-WS 2 , bridging ZnO nanowire surface and WS 2 shell, might play a role of energy barrier, preventing the backward diffusion of charge carriers into ZnO nanowire.
Kempen, Paul J; Kircher, Moritz F; de la Zerda, Adam; Zavaleta, Cristina L; Jokerst, Jesse V; Mellinghoff, Ingo K; Gambhir, Sanjiv S; Sinclair, Robert
2015-01-01
The growing use of nanoparticles in biomedical applications, including cancer diagnosis and treatment, demands the capability to exactly locate them within complex biological systems. In this work a correlative optical and scanning electron microscopy technique was developed to locate and observe multi-modal gold core nanoparticle accumulation in brain tumor models. Entire brain sections from mice containing orthotopic brain tumors injected intravenously with nanoparticles were imaged using both optical microscopy to identify the brain tumor, and scanning electron microscopy to identify the individual nanoparticles. Gold-based nanoparticles were readily identified in the scanning electron microscope using backscattered electron imaging as bright spots against a darker background. This information was then correlated to determine the exact location of the nanoparticles within the brain tissue. The nanoparticles were located only in areas that contained tumor cells, and not in the surrounding healthy brain tissue. This correlative technique provides a powerful method to relate the macro- and micro-scale features visible in light microscopy with the nanoscale features resolvable in scanning electron microscopy. Copyright © 2014 Elsevier Ltd. All rights reserved.
NASA Astrophysics Data System (ADS)
Dehghanipour, M.; Khanzadeh, M.; Karimipour, M.; Molaei, M.
2018-03-01
In this research, four different types of Ag2S@ZnS core-shells were synthesized and their nonlinear optical (NLO) properties were investigated using a Z-scan technique by a 532 nm laser diode. Here, Ag2S and ZnS nanoparticles were also synthesized and their NLO properties were compared with Ag2S@ZnS core-shells. It was observed that the NLO properties of Ag2S@ZnS quantum dots significantly increased by increasing the values of Zn(NO3)2 and thioglycolic acid (TGA). It was also observed that the NLO properties of Ag2S@ZnS core-shells for 0.1 g of Zn(NO3)2 and 7000 μl TGA is higher than sole Ag2S and ZnS nanoparticles. In open aperture Z-scan curve of ZnS sample, a saturable absorption peak was observed and this peak was seen also in type of Ag2S@ZnS nanoparticles which the value of Zn(NO3)2 much more.
Detection of trace metallic elements in oral lichenoid contact lesions using SR-XRF, PIXE, and XAFS
Sugiyama, Tomoko; Uo, Motohiro; Wada, Takahiro; Omagari, Daisuke; Komiyama, Kazuo; Miyazaki, Serika; Numako, Chiya; Noguchi, Tadahide; Jinbu, Yoshinori; Kusama, Mikio; Mori, Yoshiyuki
2015-01-01
Oral lichen planus (OLP) and oral lichenoid contact lesions (OLCL) are chronic inflammatory mucocutaneous reactions with a risk of malignant transformation that alter the epithelium. OLP and OLCL have similar clinical and histopathological features and it is difficult to distinguish one from the other. Metallic restorations are suspected to generate OLCLs. Trace metal analysis of OLCL specimens may facilitate the discrimination of symptoms and identification of causative metallic restorations. The purpose of this study was to assess OLCL tissue samples for the prevalence of metallic elements derived from dental restorations, and to discriminate OLCL from OLP by using synchrotron radiation-excited X-ray fluorescence analysis (SR-XRF), particle-induced X-ray emission (PIXE), and X-ray absorption fine structure (XAFS). Typical elements of dental materials were detected in the OLCL, whereas no obvious element accumulation was detected in OLP and negative control specimens. The origin of the detected metallic elements was presumed to be dental alloys through erosion. Therefore, our findings support the feasibility of providing supporting information to distinguish OLCL from OLP by using elemental analysis. PMID:26085368
Novel Organically Modified Core-Shell Clay for Epoxy Composites-"SOBM Filler 1".
Iheaturu, Nnamdi Chibuike; Madufor, Innocent Chimezie
2014-01-01
Preparation of a novel organically modified clay from spent oil base drilling mud (SOBM) that could serve as core-shell clay filler for polymers is herein reported. Due to the hydrophilic nature of clay, its compatibility with polymer matrix was made possible through modification of the surface of the core clay sample with 3-aminopropyltriethoxysilane (3-APTES) compound prior to its use. Fourier transform infrared (FT-IR) spectroscopy was used to characterize clay surface modification. Electron dispersive X-ray diffraction (EDX) and scanning electron microscopy (SEM) were used to expose filler chemical composition and morphology, while electrophoresis measurement was used to examine level of filler dispersion. Results show an agglomerated core clay powder after high temperature treatment, while EDX analysis shows that the organically modified clay is composed of chemical inhomogeneities, wherein elemental compositions in weight percent vary from one point to the other in a probe of two points. Micrographs of the 3-APTES coupled SOBM core-shell clay filler clearly show cloudy appearance, while FT-IR indicates 25% and 5% increases in fundamental vibrations band at 1014 cm(-1) and 1435 cm(-1), respectively. Furthermore, 3-APTES coupled core-shell clay was used to prepare epoxy composites and tested for mechanical properties.
Core-core and core-valence correlation energy atomic and molecular benchmarks for Li through Ar
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ranasinghe, Duminda S.; Frisch, Michael J.; Petersson, George A., E-mail: gpetersson@wesleyan.edu
2015-12-07
We have established benchmark core-core, core-valence, and valence-valence absolute coupled-cluster single double (triple) correlation energies (±0.1%) for 210 species covering the first- and second-rows of the periodic table. These species provide 194 energy differences (±0.03 mE{sub h}) including ionization potentials, electron affinities, and total atomization energies. These results can be used for calibration of less expensive methodologies for practical routine determination of core-core and core-valence correlation energies.
... Gallbladder scan; Biliary scan; Cholescintigraphy; HIDA; Hepatobiliary nuclear imaging scan ... test results. This test is combined with other imaging (such as CT or ultrasound). After the gallbladder ...
Computed tomography scan - abdomen; CT scan - abdomen; CT abdomen and pelvis ... An abdominal CT scan makes detailed pictures of the structures inside your belly very quickly. This test may be used to look ...
NASA Technical Reports Server (NTRS)
1990-01-01
Spang & Company's new configuration of converter transformer cores is a composite of gapped and ungapped cores assembled together in concentric relationship. The net effect of the composite design is to combine the protection from saturation offered by the gapped core with the lower magnetizing requirement of the ungapped core. The uncut core functions under normal operating conditions and the cut core takes over during abnormal operation to prevent power surges and their potentially destructive effect on transistors. Principal customers are aerospace and defense manufacturers. Cores also have applicability in commercial products where precise power regulation is required, as in the power supplies for large mainframe computers.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Dill, R.F.; Slosson, J.E.; McEachen, D.B.
1990-05-01
A Macintosh II{sup TM} computer and commercially available software were used to analyze and depict the topography, construct an isopach sediment thickness map, plot core positions, and locate the geology of an offshore area facing an active landslide on the southern side of Palos Verdes Peninsula California. Profile data from side scan sonar, 3.5 kHz, and Boomer subbottom, high-resolution seismic, diving, echo sounder traverses, and cores - all controlled with a mini Ranger II navigation system - were placed in MacGridzo{sup TM} and WingZ{sup TM} software programs. The computer-plotted data from seven sources were used to construct maps with overlaysmore » for evaluating the possibility of a shoreside landslide extending offshore. The poster session describes the offshore survey system and demonstrates the development of the computer data base, its placement into the MacGridzo{sup TM} gridding program, and transfer of gridded navigational locations to the WingZ{sup TM} data base and graphics program. Data will be manipulated to show how sea-floor features are enhanced and how isopach data were used to interpret the possibility of landslide displacement and Holocene sea level rise. The software permits rapid assessment of data using computerized overlays and a simple, inexpensive means of constructing and evaluating information in map form and the preparation of final written reports. This system could be useful in many other areas where seismic profiles, precision navigational locations, soundings, diver observations, and core provide a great volume of information that must be compared on regional plots to develop of field maps for geological evaluation and reports.« less
Mesoporous activated carbon from corn stalk core for lithium ion batteries
NASA Astrophysics Data System (ADS)
Li, Yi; Li, Chun; Qi, Hui; Yu, Kaifeng; Liang, Ce
2018-04-01
A novel mesoporous activated carbon (AC) derived from corn stalk core is prepared via a facile and effective method which including the decomposition and carbonization of corn stalk core under an inert gas atmosphere and further activation process with KOH solution. The mesoporous activated carbon (AC) is characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) measurements. These biomass waste derived from activated carbon is proved to be promising anode materials for high specific capacity lithium ion batteries. The activated carbon anode possesses excellent reversible capacity of 504 mAh g-1 after 100 cycles at 0.2C. Compared with the unactivated carbon (UAC), the electrochemical performance of activated carbon is significantly improved due to its mesoporous structure.
Optimizing performance by improving core stability and core strength.
Hibbs, Angela E; Thompson, Kevin G; French, Duncan; Wrigley, Allan; Spears, Iain
2008-01-01
Core stability and core strength have been subject to research since the early 1980s. Research has highlighted benefits of training these processes for people with back pain and for carrying out everyday activities. However, less research has been performed on the benefits of core training for elite athletes and how this training should be carried out to optimize sporting performance. Many elite athletes undertake core stability and core strength training as part of their training programme, despite contradictory findings and conclusions as to their efficacy. This is mainly due to the lack of a gold standard method for measuring core stability and strength when performing everyday tasks and sporting movements. A further confounding factor is that because of the differing demands on the core musculature during everyday activities (low load, slow movements) and sporting activities (high load, resisted, dynamic movements), research performed in the rehabilitation sector cannot be applied to the sporting environment and, subsequently, data regarding core training programmes and their effectiveness on sporting performance are lacking. There are many articles in the literature that promote core training programmes and exercises for performance enhancement without providing a strong scientific rationale of their effectiveness, especially in the sporting sector. In the rehabilitation sector, improvements in lower back injuries have been reported by improving core stability. Few studies have observed any performance enhancement in sporting activities despite observing improvements in core stability and core strength following a core training programme. A clearer understanding of the roles that specific muscles have during core stability and core strength exercises would enable more functional training programmes to be implemented, which may result in a more effective transfer of these skills to actual sporting activities.
NASA Astrophysics Data System (ADS)
Garvie, Laurence A. J.; Baumgardner, Grant; Buseck, Peter R.
2008-05-01
Carbonaceous nanoglobules are ubiquitous in carbonaceous chondrite (CC) meteorites. The Tagish Lake (C2) meteorite is particularly intriguing in containing an abundance of nanoglobules, with a wider range of forms and sizes than encountered in other CC meteorites. Previous studies by transmission electron microscopy (TEM) have provided a wealth of information on chemistry and structure. In this study low voltage scanning electron microscopy (SEM) was used to characterize the globule forms and external structures. The internal structure of the globules was investigated after sectioning by focused ion beam (FIB) milling. The FIB-SEM analysis shows that the globules range from solid to hollow. Some hollow globules show a central open core, with adjoining smaller cores. The FIB with an SEM is a valuable tool for the analysis of extraterrestrial materials, even of sub-micron-sized "soft" carbonaceous particles. The rapid site-specific cross-sectioning capabilities of the FIB allow the preservation of the internal morphology of the nanoglobules, with minimal damage or alteration of the unsectioned areas.
Characterization of rock thermal conductivity by high-resolution optical scanning
Popov, Y.A.; Pribnow, D.F.C.; Sass, J.H.; Williams, C.F.; Burkhardt, H.
1999-01-01
We compared thress laboratory methods for thermal conductivity measurements: divided-bar, line-source and optical scanning. These methods are widely used in geothermal and petrophysical studies, particularly as applied to research on cores from deep scientific boreholes. The relatively new optical scanning method has recently been perfected and applied to geophysical problems. A comparison among these methods for determining the thermal conductivity tensor for anisotropic rocks is based on a representative collection of 80 crystalline rock samples from the KTB continental deep borehole (Germany). Despite substantial thermal inhomogeneity of rock thermal conductivity (up to 40-50% variation) and high anisotropy (with ratios of principal values attaining 2 and more), the results of measurements agree very well among the different methods. The discrepancy for measurements along the foliation is negligible (<1%). The component of thermal conductivity normal to the foliation reveals somewhat larger differences (3-4%). Optical scanning allowed us to characterize the thermal inhomogeneity of rocks and to identify a three-dimensional anisotropy in thermal conductivity of some gneiss samples. The merits of optical scanning include minor random errors (1.6%), the ability to record the variation of thermal conductivity along the sample, the ability to sample deeply using a slow scanning rate, freedom from constraints for sample size and shape, and quality of mechanical treatment of the sample surface, a contactless mode of measurement, high speed of operation, and the ability to measure on a cylindrical sample surface. More traditional methods remain superior for characterizing bulk conductivity at elevated temperature.Three laboratory methods including divided-bar, line-source and optical scanning are widely applied in geothermal and petrophysical studies. In this study, these three methods were compared for determining the thermal conductivity tensor for anisotropic rocks
Update on the MRI Core of the Alzheimer's Disease Neuroimaging Initiative
Jack, Clifford R; Bernstein, Matt A; Borowski, Bret J; Gunter, Jeffrey L; Fox, Nick C; Thompson, Paul M; Schuff, Norbert; Krueger, Gunnar; Killiany, Ronald J; DeCarli, Charles S; Dale, Anders M; Weiner, Michael W
2010-01-01
Functions of the ADNI MRI core fall into three categories: (1) those of the central MRI core lab at Mayo Clinic, Rochester, Minnesota, needed to generate high quality MRI data in all subjects at each time point; (2) those of the funded ADNI MRI core imaging analysis groups responsible for analyzing the MRI data, and (3) the joint function of the entire MRI core in designing and problem solving MR image acquisition, pre-processing and analyses methods. The primary objective of ADNI was and continues to be improving methods for clinical trials in Alzheimer's disease. Our approach to the present (“ADNI-GO”) and future (“ADNI-2”, if funded) MRI protocol will be to maintain MRI methodological consistency in previously enrolled “ADNI-1” subjects who are followed longitudinally in ADNI-GO and ADNI-2. We will modernize and expand the MRI protocol for all newly enrolled ADNI-GO and ADNI-2 subjects. All newly enrolled subjects will be scanned at 3T with a core set of three sequence types: 3D T1-weighted volume, FLAIR, and a long TE gradient echo volumetric acquisition for micro hemorrhage detection. In addition to this core ADNI-GO and ADNI-2 protocol, we will perform vendor specific pilot sub-studies of arterial spin labeling perfusion, resting state functional connectivity and diffusion tensor imaging. One each of these sequences will be added to the core protocol on systems from each MRI vendor. These experimental sub-studies are designed to demonstrate the feasibility of acquiring useful data in a multi-center (but single vendor) setting for these three emerging MRI applications. PMID:20451869
NASA Astrophysics Data System (ADS)
Schaumann, Ina; Malzer, Wolfgang; Mantouvalou, Ioanna; Lühl, Lars; Kanngießer, Birgit; Dargel, Rainer; Giese, Ulrich; Vogt, Carla
2009-04-01
For the validation of the quantification of the newly-developed method of 3D Micro X-ray fluorescence spectroscopy (3D Micro-XRF) samples with a low average Z matrix and minor high Z elements are best suited. In a light matrix the interferences by matrix effects are minimized so that organic polymers are appropriate as basis for analytes which are more easily detected by X-ray fluorescence spectroscopy. Polymer layer systems were assembled from single layers of ethylene-propylene-diene rubber (EPDM) filled with changing concentrations of silica and zinc oxide as inorganic additives. Layer thicknesses were in the range of 30-150 μm. Before the analysis with 3D Micro-XRF all layers have been characterized by scanning micro-XRF with regard to filler dispersion, by infrared microscopy and light microscopy in order to determine the layer thicknesses and by ICP-OES to verify the concentration of the X-ray sensitive elements in the layers. With the results obtained for stacked polymer systems the validity of the analytical quantification model for the determination of stratified materials by 3D Micro-XRF could be demonstrated.
NASA Astrophysics Data System (ADS)
Kvisvik, Bjørn Christian; Paasche, Øyvind; Olaf Dahl, Svein
2014-05-01
Skriufonnen, a small cirque glacier (0.4 km2) in Southern Norway, has been monitored for the last 10 years, revealing a short response time to on-going climate change. This is the only remaining glacier in the central mountain massif known as Rondane where investigations of past climate variability are scarce. A series of short (HTH, n=8) and long (piston, n=6) cores from two lakes located downstream of Skriufonnen were retrieved and sediments were dated and analysed. In order to complement and validate lake sediment interpretations i.e., the potential connection to glacier variability, a number of soil samples was collected from the surrounding catchment. The six 110 mm piston cores (< 3.1 m length) and eight sediment surface cores were analysed for grain size distribution, geochemical elements (ITRAX XRF-scanning), organic matter content (LOI), magnetic parameters (magnetic susceptibility; surface and bulk), anhysteretic remanent magnetization (ARM) and Saturation Isothermal remanent magnetizations (sIRM). Consistent age-depth relationships were obtained by AMS-C14 and Pb210 dates showing that the cores cover at least the last 10 000 years. High-resolution analysis (XRF and MS) reveals centennial trends, but also distinct changes in frequency and amplitude. A quiescent period during the Holocene Thermal Optimum (9-6 ka) is followed by a sudden onset of Neoglacial (3.8 ka) activity peaking at 2.4 ka. The Little Ice Age (LIA) peaked at 1800 AD. A weak magnetic signal is observed in all cores. This is explained by the fact that Rondane is made of Sparagmite, an arkosic sandstone partly consisting of metamorphosed sandstone and conglomerate with high content of quarts (SiO2) (between 80 to 87 %) and Feldspar. The Sparagmite is resistant to chemical weathering, making the soils dry and sandy. Catchment sediment samples, running in a transect all the way up from the lakes to the glacier snout were sieved into various size classes (250, 125, 63, 38, 20 μm) prior to
Green synthesis and characterization of size tunable silica-capped gold core-shell nanoparticles
NASA Astrophysics Data System (ADS)
Wangoo, Nishima; Shekhawat, Gajendra; Wu, Jin-Song; Bhasin, Aman K. K.; Suri, C. R.; Bhasin, K. K.; Dravid, Vinayak
2012-08-01
Silica-coated gold nanoparticles (Au@SiO2) with controlled silica-shell thickness were prepared by a modified Stober's method using 10-nm gold nanoparticles (AuNPs) as seeds. The AuNPs were silica-coated with a sol-gel reaction using tetraethylorthosilicate (TEOS) as a silica source and ammonia as a catalyst. An increase in TEOS concentration resulted in an increase in shell thickness. The NPs were characterized by transmission electron microscopy, selected area electron diffraction, energy-dispersive X-ray spectroscopy, scanning near-field ultrasound holography and scanning transmission electron microscopy. The method required no surface modification and the synthesized core shell nanoparticles can be used for various types of biological applications.
Hu, Kun; Huang, Xiaoxia; Gao, Yongqing; Huang, Xulin; Xiao, Hang; McClements, David Julian
2015-09-01
Biopolymer core-shell nanoparticles were fabricated using a hydrophobic protein (zein) as the core and a hydrophilic polysaccharide (pectin) as the shell. Particles were prepared by coating cationic zein nanoparticles with anionic pectin molecules using electrostatic deposition (pH 4). The core-shell nanoparticles were fortified with curcumin (a hydrophobic bioactive molecule) at a high loading efficiency (>86%). The resulting nanoparticles were spherical, relatively small (diameter ≈ 250 nm), and had a narrow size distribution (polydispersity index ≈ 0.24). The encapsulated curcumin was in an amorphous (rather than crystalline form) as detected by differential scanning calorimetry (DSC). Fourier transform infrared (FTIR) and Raman spectra indicated that the encapsulated curcumin interacted with zein mainly through hydrophobic interactions. The nanoparticles were converted into a powdered form that had good water-dispersibility. These core-shell biopolymer nanoparticles could be useful for incorporating curcumin into functional foods and beverages, as well as dietary supplements and pharmaceutical products. Copyright © 2015 Elsevier Ltd. All rights reserved.
Effect of annealing temperature on the stress and structural properties of Ge core fibre
NASA Astrophysics Data System (ADS)
Zhao, Ziwen; Cheng, Xueli; Xue, Fei; He, Ting; Wang, Tingyun
2017-09-01
Effect of annealing temperature on the stress and structural properties of a Ge core fibre via the molten core drawing (MCD) method is investigated using Raman spectroscopy, Scanning electronic microscopy (SEM), and X-ray diffraction. The experimental results showed that the Raman peak position of the Ge fibre shifted from 297.6 cm-1 to 300.5 cm-1, and the FWHM value decreased from 4.53 cm-1 to 4.31 cm-1, when the annealing is carried out at 700 °C, 800 °C, and 900 °C, respectively. For the Ge core annealed at 900 °C, an apparent crystal grain can be seen in the SEM image, and the diffraction peaks of the (3 3 1) plane are generated in the X-ray diffraction spectra. These results show that optimising the annealing temperature allows the release of the residual stress in the Ge core. When the Ge core fibre is annealed at 900 °C, it exhibits the lowest residual stress and the highest crystal quality, and the quality improvement relative to that of the sample annealed at 800 °C is significant. Hence, annealing at around 900 °C can greatly improve the quality of a Ge core fibre. Further performance improvement of the Ge core fibre by annealing techniques can be anticipated.
NASA Astrophysics Data System (ADS)
Li, Chen; Zhang, Yu-Yang; Pennycook, Timothy J.; Wu, Yelong; Lupini, Andrew R.; Paudel, Naba; Pantelides, Sokrates T.; Yan, Yanfa; Pennycook, Stephen J.
2016-10-01
The dynamics of partial dislocations in CdTe have been observed at the atomic scale using aberration-corrected scanning transmission electron microscopy (STEM), allowing the mobility of different dislocations to be directly compared: Cd-core Shockley partial dislocations are more mobile than Te-core partials, and dislocation cores with unpaired columns have higher mobility than those without unpaired columns. The dynamic imaging also provides insight into the process by which the dislocations glide. Dislocations with dangling bonds on unpaired columns are found to be more mobile because the dangling bonds mediate the bond exchanges required for the dislocations to move. Furthermore, a screw dislocation has been resolved to dissociate into a Shockley partial-dislocation pair along two different directions, revealing a way for the screw dislocation to glide in the material. The results show that dynamic STEM imaging has the potential to uncover the details of dislocation motion not easily accessible by other means.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Wang, Yung-Chen Andrew; Engelhard, Mark H.; Baer, Donald R.
2016-03-07
Abstract or short description: Spectral modeling of photoelectrons can serve as a valuable tool when combined with X-ray photoelectron spectroscopy (XPS) analysis. Herein, a new version of the NIST Simulation of Electron Spectra for Surface Analysis (SESSA 2.0) software, capable of directly simulating spherical multilayer NPs, was applied to model citrate stabilized Au/Ag-core/shell nanoparticles (NPs). The NPs were characterized using XPS and scanning transmission electron microscopy (STEM) to determine the composition and morphology of the NPs. The Au/Ag-core/shell NPs were observed to be polydispersed in size, non-circular, and contain off-centered Au-cores. Using the average NP dimensions determined from STEM analysis,more » SESSA spectral modeling indicated that washed Au/Ag-core shell NPs were stabilized with a 0.8 nm l« less
NASA Astrophysics Data System (ADS)
Vittiglio, G.; Janssens, K.; Vekemans, B.; Adams, F.; Oost, A.
1999-11-01
The analytical characteristics, possibilities and limitations of a compact and easily transportable small-beam XRF instrument are described. The instrument consists of a compact, mini-focus Mo X-ray tube that is collimated to produce a sub-mm beam and a peltier-cooled PIN diode detector. Relative MDLs in highly scattering matrices are situated in the 10-100-ppm range; for metallic matrices featuring strong matrix lines, the MDLs of the instrument are approximately a factor 2 higher. Since only a small irradiation area is required, a simple micro-polishing technique that may be performed in situ in combination with the measurements is shown to be effective for the determination of the bulk composition of corroded bronze objects. As an example, a series of Egyptian bronze objects date from XXII nd Egyptian Dynasty (ca. 1090 BC) to the Roman era (30 BC to 640 AD) was analyzed in order to contribute to the very limited database on Cu-alloy compositions from this period.
... this page: //medlineplus.gov/ency/article/003330.htm CT scan To use the sharing features on this page, please enable JavaScript. A computed tomography (CT) scan is an imaging method that uses x- ...
Precursor and Neutral Loss Scans in an RF Scanning Linear Quadrupole Ion Trap
NASA Astrophysics Data System (ADS)
Snyder, Dalton T.; Szalwinski, Lucas J.; Schrader, Robert L.; Pirro, Valentina; Hilger, Ryan; Cooks, R. Graham
2018-03-01
Methodology for performing precursor and neutral loss scans in an RF scanning linear quadrupole ion trap is described and compared to the unconventional ac frequency scan technique. In the RF scanning variant, precursor ions are mass selectively excited by a fixed frequency resonance excitation signal at low Mathieu q while the RF amplitude is ramped linearly to pass ions through the point of excitation such that the excited ion's m/z varies linearly with time. Ironically, a nonlinear ac frequency scan is still required for ejection of the product ions since their frequencies vary nonlinearly with the linearly varying RF amplitude. In the case of the precursor scan, the ejection frequency must be scanned so that it is fixed on a product ion m/z throughout the RF scan, whereas in the neutral loss scan, it must be scanned to maintain a constant mass offset from the excited precursor ions. Both simultaneous and sequential permutation scans are possible; only the former are demonstrated here. The scans described are performed on a variety of samples using different ionization sources: protonated amphetamine ions generated by nanoelectrospray ionization (nESI), explosives ionized by low-temperature plasma (LTP), and chemical warfare agent simulants sampled from a surface and analyzed with swab touch spray (TS). We lastly conclude that the ac frequency scan variant of these MS/MS scans is preferred due to electronic simplicity. In an accompanying manuscript, we thus describe the implementation of orthogonal double resonance precursor and neutral loss scans on the Mini 12 using constant RF voltage. [Figure not available: see fulltext.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Murthy, N. Sanjeeva; Zhang, Zheng; Borsadia, Siddharth
The structural changes in nanospheres with a crystalline core and an amorphous diffuse shell were investigated by small-angle neutron scattering (SANS), small-, medium-, and wide-angle X-ray scattering (SAXS, MAXS and WAXS), and differential scanning calorimetry (DSC).
DOE Office of Scientific and Technical Information (OSTI.GOV)
Sang, Xiahan; Lupini, Andrew R.; Ding, Jilai
Atomic-resolution imaging in an aberration-corrected scanning transmission electron microscope (STEM) can enable direct correlation between atomic structure and materials functionality. The fast and precise control of the STEM probe is, however, challenging because the true beam location deviates from the assigned location depending on the properties of the deflectors. To reduce these deviations, i.e. image distortions, we use spiral scanning paths, allowing precise control of a sub-Å sized electron probe within an aberration-corrected STEM. Although spiral scanning avoids the sudden changes in the beam location (fly-back distortion) present in conventional raster scans, it is not distortion-free. “Archimedean” spirals, with amore » constant angular frequency within each scan, are used to determine the characteristic response at different frequencies. We then show that such characteristic functions can be used to correct image distortions present in more complicated constant linear velocity spirals, where the frequency varies within each scan. Through the combined application of constant linear velocity scanning and beam path corrections, spiral scan images are shown to exhibit less scan distortion than conventional raster scan images. The methodology presented here will be useful for in situ STEM imaging at higher temporal resolution and for imaging beam sensitive materials.« less
NASA Astrophysics Data System (ADS)
Sang, Xiahan; Lupini, Andrew R.; Ding, Jilai; Kalinin, Sergei V.; Jesse, Stephen; Unocic, Raymond R.
2017-03-01
Atomic-resolution imaging in an aberration-corrected scanning transmission electron microscope (STEM) can enable direct correlation between atomic structure and materials functionality. The fast and precise control of the STEM probe is, however, challenging because the true beam location deviates from the assigned location depending on the properties of the deflectors. To reduce these deviations, i.e. image distortions, we use spiral scanning paths, allowing precise control of a sub-Å sized electron probe within an aberration-corrected STEM. Although spiral scanning avoids the sudden changes in the beam location (fly-back distortion) present in conventional raster scans, it is not distortion-free. “Archimedean” spirals, with a constant angular frequency within each scan, are used to determine the characteristic response at different frequencies. We then show that such characteristic functions can be used to correct image distortions present in more complicated constant linear velocity spirals, where the frequency varies within each scan. Through the combined application of constant linear velocity scanning and beam path corrections, spiral scan images are shown to exhibit less scan distortion than conventional raster scan images. The methodology presented here will be useful for in situ STEM imaging at higher temporal resolution and for imaging beam sensitive materials.
Sang, Xiahan; Lupini, Andrew R; Ding, Jilai; Kalinin, Sergei V; Jesse, Stephen; Unocic, Raymond R
2017-03-08
Atomic-resolution imaging in an aberration-corrected scanning transmission electron microscope (STEM) can enable direct correlation between atomic structure and materials functionality. The fast and precise control of the STEM probe is, however, challenging because the true beam location deviates from the assigned location depending on the properties of the deflectors. To reduce these deviations, i.e. image distortions, we use spiral scanning paths, allowing precise control of a sub-Å sized electron probe within an aberration-corrected STEM. Although spiral scanning avoids the sudden changes in the beam location (fly-back distortion) present in conventional raster scans, it is not distortion-free. "Archimedean" spirals, with a constant angular frequency within each scan, are used to determine the characteristic response at different frequencies. We then show that such characteristic functions can be used to correct image distortions present in more complicated constant linear velocity spirals, where the frequency varies within each scan. Through the combined application of constant linear velocity scanning and beam path corrections, spiral scan images are shown to exhibit less scan distortion than conventional raster scan images. The methodology presented here will be useful for in situ STEM imaging at higher temporal resolution and for imaging beam sensitive materials.
Sang, Xiahan; Lupini, Andrew R.; Ding, Jilai; ...
2017-03-08
Atomic-resolution imaging in an aberration-corrected scanning transmission electron microscope (STEM) can enable direct correlation between atomic structure and materials functionality. The fast and precise control of the STEM probe is, however, challenging because the true beam location deviates from the assigned location depending on the properties of the deflectors. To reduce these deviations, i.e. image distortions, we use spiral scanning paths, allowing precise control of a sub-Å sized electron probe within an aberration-corrected STEM. Although spiral scanning avoids the sudden changes in the beam location (fly-back distortion) present in conventional raster scans, it is not distortion-free. “Archimedean” spirals, with amore » constant angular frequency within each scan, are used to determine the characteristic response at different frequencies. We then show that such characteristic functions can be used to correct image distortions present in more complicated constant linear velocity spirals, where the frequency varies within each scan. Through the combined application of constant linear velocity scanning and beam path corrections, spiral scan images are shown to exhibit less scan distortion than conventional raster scan images. The methodology presented here will be useful for in situ STEM imaging at higher temporal resolution and for imaging beam sensitive materials.« less
Characterization of the Fault Core and Damage Zone of the Borrego Fault, 2010 M7.2 Rupture
NASA Astrophysics Data System (ADS)
Dorsey, M. T.; Rockwell, T. K.; Girty, G.; Ostermeijer, G.; Mitchell, T. M.; Fletcher, J. M.
2017-12-01
We collected a continuous sample of the fault core and 23 samples of the damage zone out to 52 m across the rupture trace of the 2010 M7.2 El Mayor-Cucapa earthquake to characterize the physical damage and chemical transformations associated with this active seismic source. In addition to quantifying fracture intensity from macroscopic analysis, we cut a continuous thin section through the fault core and from various samples in the damage zone, and ran each sample for XRD analyses for clay mineralogy, XRF for bulk geochemical analyses, and bulk and grain density from which porosity and volumetric strain were derived. The parent rock is a hydrothermally-altered biotite tonalite, with biotite partially altered to chlorite. The presence of epidote with chlorite suggests that these rocks were subjected to relatively high temperatures of 300-400° C. Adjacent to the outermost damage zone is a chaotic breccia zone with distinct chemical and physical characteristics, indicating possible connection to an ancestral fault to the southwest. The damage zone consists of an outer zone of protocataclasite, which grades inward towards mesocataclasite with seams of ultracataclasite. The fault core is anomalous in that it is largely composed of a sliver of marble that has been translated along the fault, so direct comparison with the damage zone is impaired. From collected data, we observe that chloritization increases into the breccia and damage zones, as does the presence of illite. Porosity reaches maximum values in the damage zone adjacent to the core, and closely follows trends in fracture intensity. Statistically significant gains in Mg, Na, K, Mn, and total bulk mass occurred within the inner damage zone, with losses of Ca and P mass, which led to the formation of chlorite and albite. The outer damage zone displays gains in Mg and Na mass with losses in Ca and P mass. The breccia zone shows gains in mass of Mg and Mn and loss in total bulk mass. A gain in LOI in both the
... cross-sectional pictures of your body. Doctors use CT scans to look for Broken bones Cancers Blood clots Signs of heart disease Internal bleeding During a CT scan, you lie still on a table. The table ...
... scan is an imaging test used to diagnose bone diseases and find out how severe they are. How ... a 3-phase bone scan. To evaluate metastatic bone disease, images are taken only after the 3- to ...
Deglaciation in the High Andes - a Record from Laguna Piuray (Cusco, Peru)
NASA Astrophysics Data System (ADS)
Nederbragt, A.; Thurow, J.; Brumsack, H.; Lowe, J.; Pearce, R.; Ramsey, C.
2007-12-01
The Peruvian Andes lie in a crucial location for paleoclimate investigation. Fluctuating Pacific and Atlantic air masses compete for long-term dominance of the region, with the El-Nino Southern Oscillation (ENSO) system causing further variability. A laminated glacial/interglacial sediment sequence (6m) exposed around the shores of Laguna Piuray, near Cusco, offers not only the potential to reconstruct the climate history of the area but also to test for strength and frequency of the Atlantic monsoonal and Pacific ENSO influence. A suite of continuous cores was collected from deep trenches. The sedimentary record is characterized by postglacial diatom-rich chalk overlying organic-rich clayey chalk. Between these units are 3 distinct organic layers (80% TOC) deposited between 12-14 cal. kyr BP (14C). The base of the record is probably as old as 25kyrs (U/Th). We obtained a multi- proxy record of the section including continuous XRF scanning data of the entire sequence, and stable isotopes, XRF, XRD, TOC, biogenic opal, and carbonate analysis of discrete samples as well as a relative paleotemperature record from analyses of soil biomarkers. All the data profiles we obtained show a pronounced increase in temperature and decrease in precipitation at 13.8kyrs and are in good correlation with published regional Andean records using single proxies. Our results confirm that the Deglaciation Cold Reversal in central South America is not identical to the Younger Dryas event in the Northern Hemisphere.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bourassa, Daisy; Gleber, Sophie-Charlotte; Vogt, Stefan
2016-01-01
Transition metals such as zinc, copper, and iron play key roles in cellular proliferation, cell differentiation, growth, and development. Over the past decade, advances in synchrotron X-ray fluorescence instrumentation presented new opportunities for the three-dimensional mapping of trace metal distributions within intact specimens. Taking advantage of microXRF tomography, we visualized the 3D distribution of zinc and iron in a zebrafish embryo at the onset of the hatching period. The reconstructed volumetric data revealed distinct differences in the elemental distributions, with zinc predominantly localized to the yolk and yolk extension, and iron to various regions of the brain as well asmore » the myotome extending along the dorsal side of the embryo. The data set complements an earlier tomographic study of an embryo at the pharyngula stage (24 hpf), thus offering new insights into the trace metal distribution at key stages of embryonic development.« less
NASA Astrophysics Data System (ADS)
Date, Kumi; Ishigure, Takaaki
2017-02-01
Polymer optical waveguides with graded-index (GI) circular cores are fabricated using the Mosquito method, in which the positions of parallel cores are accurately controlled. Such an accurate arrangement is of great importance for a high optical coupling efficiency with other optical components such as fiber ribbons. In the Mosquito method that we developed, a core monomer with a viscous liquid state is dispensed into another liquid state monomer for cladding via a syringe needle. Hence, the core positions are likely to shift during or after the dispensing process due to several factors. We investigate the factors, specifically affecting the core height. When the core and cladding monomers are selected appropriately, the effect of the gravity could be negligible, so the core height is maintained uniform, resulting in accurate core heights. The height variance is controlled in +/-2 micrometers for the 12 cores. Meanwhile, larger shift in the core height is observed when the needle-tip position is apart from the substrate surface. One of the possible reasons of the needle-tip height dependence is the asymmetric volume contraction during the monomer curing. We find a linear relationship between the original needle-tip height and the core-height observed. This relationship is implemented in the needle-scan program to stabilize the core height in different layers. Finally, the core heights are accurately controlled even if the cores are aligned on various heights. These results indicate that the Mosquito method enables to fabricate waveguides in which the cores are 3-dimensionally aligned with a high position accuracy.
CAT scan - lumbar spine; Computed axial tomography scan - lumbar spine; Computed tomography scan - lumbar spine; CT - lower back ... CT scans rapidly makes detailed pictures of the lower back. The test may be used to look for: ...
Tagmatarchis, Alexander; Tripodakis, Aris-Petros; Filippatos, Gerasimos; Zinelis, Spiros; Eliades, George
2014-01-01
The aim of the study was to characterize the elemental distribution at the interface between all-ceramic core and veneering porcelain materials. Three groups of all-ceramic cores were selected: A) Glass-ceramics (Cergo, IPS Empress, IPS Empress 2, e-max Press, Finesse); B) Glass-infiltrated ceramics (Celay Alumina, Celay Zirconia) and C) Densely sintered ceramics (Cercon, Procera Alumina, ZirCAD, Noritake Zirconia). The cores were combined with compatible veneering porcelains and three flat square test specimens were produced for each system. The core-veneer interfaces were examined by scanning electron microscopy and energy dispersive x-ray microanalysis. The glass-ceramic systems showed interfacial zones reach in Si and O, with the presence of K, Ca, Al in core and Ca, Ce, Na, Mg or Al in veneer material, depending on the system tested. IPS Empress and IPS Empress 2 demonstrated distinct transitional phases at the core-veneer interface. In the glassinfiltrated systems, intermixing of core (Ce, La) with veneer (Na, Si) elements occurred, whereas an abrupt drop of the core-veneer elemental concentration was documented at the interfaces of all densely sintered ceramics. The results of the study provided no evidence of elemental interdiffusion at the core-veneer interfaces in densely sintered ceramics, which implies lack of primary chemical bonding. For the glass-containing systems (glassceramics and glass-infiltrated ceramics) interdiffusion of the glass-phase seems to play a critical role in establishing a primary bonding condition between ceramic core and veneering porcelain.
Postprocessing Algorithm for Driving Conventional Scanning Tunneling Microscope at Fast Scan Rates.
Zhang, Hao; Li, Xianqi; Chen, Yunmei; Park, Jewook; Li, An-Ping; Zhang, X-G
2017-01-01
We present an image postprocessing framework for Scanning Tunneling Microscope (STM) to reduce the strong spurious oscillations and scan line noise at fast scan rates and preserve the features, allowing an order of magnitude increase in the scan rate without upgrading the hardware. The proposed method consists of two steps for large scale images and four steps for atomic scale images. For large scale images, we first apply for each line an image registration method to align the forward and backward scans of the same line. In the second step we apply a "rubber band" model which is solved by a novel Constrained Adaptive and Iterative Filtering Algorithm (CIAFA). The numerical results on measurement from copper(111) surface indicate the processed images are comparable in accuracy to data obtained with a slow scan rate, but are free of the scan drift error commonly seen in slow scan data. For atomic scale images, an additional first step to remove line-by-line strong background fluctuations and a fourth step of replacing the postprocessed image by its ranking map as the final atomic resolution image are required. The resulting image restores the lattice image that is nearly undetectable in the original fast scan data.
Postprocessing Algorithm for Driving Conventional Scanning Tunneling Microscope at Fast Scan Rates
Zhang, Hao; Li, Xianqi; Park, Jewook; Li, An-Ping
2017-01-01
We present an image postprocessing framework for Scanning Tunneling Microscope (STM) to reduce the strong spurious oscillations and scan line noise at fast scan rates and preserve the features, allowing an order of magnitude increase in the scan rate without upgrading the hardware. The proposed method consists of two steps for large scale images and four steps for atomic scale images. For large scale images, we first apply for each line an image registration method to align the forward and backward scans of the same line. In the second step we apply a “rubber band” model which is solved by a novel Constrained Adaptive and Iterative Filtering Algorithm (CIAFA). The numerical results on measurement from copper(111) surface indicate the processed images are comparable in accuracy to data obtained with a slow scan rate, but are free of the scan drift error commonly seen in slow scan data. For atomic scale images, an additional first step to remove line-by-line strong background fluctuations and a fourth step of replacing the postprocessed image by its ranking map as the final atomic resolution image are required. The resulting image restores the lattice image that is nearly undetectable in the original fast scan data. PMID:29362664
Cancer diagnosis using a conventional x-ray fluorescence camera with a cadmium-telluride detector
NASA Astrophysics Data System (ADS)
Sato, Eiichi; Enomoto, Toshiyuki; Hagiwara, Osahiko; Abudurexiti, Abulajiang; Sato, Koetsu; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun
2011-10-01
X-ray fluorescence (XRF) analysis is useful for mapping various atoms in objects. Bremsstrahlung X-rays are selected using a 3.0 mm-thick aluminum filter, and these rays are absorbed by indium, cerium and gadolinium atoms in objects. Then XRF is produced from the objects, and photons are detected by a cadmium-telluride detector. The Kα photons are discriminated using a multichannel analyzer, and the number of photons is counted by a counter card. The objects are moved and scanned by an x-y stage in conjunction with a two-stage controller, and X-ray images obtained by atomic mapping are shown on a personal computer monitor. The scan steps of the x and y axes were both 2.5 mm, and the photon-counting time per mapping point was 0.5 s. We carried out atomic mapping using the X-ray camera, and Kα photons from cerium and gadolinium atoms were produced from cancerous regions in nude mice.
NASA Astrophysics Data System (ADS)
Enomoto, Toshiyuki; Sato, Eiichi; Abderyim, Purkhet; Abudurexiti, Abulajiang; Hagiwara, Osahiko; Matsukiyo, Hiroshi; Osawa, Akihiro; Watanabe, Manabu; Nagao, Jiro; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun
2011-04-01
X-ray fluorescence (XRF) analysis is useful for mapping various molecules in objects. Bremsstrahlung X-rays are selected using a 3.0-mm-thick aluminum filter, and these rays are absorbed by iodine, cerium, and gadolinium molecules in objects. Next, XRF is produced from the objects, and photons are detected by a cadmium-telluride detector. The Kα photons are discriminated using a multichannel analyzer, and the number of photons is counted by a counter card. The objects are moved and scanned by an x- y stage in conjunction with a two-stage controller, and X-ray images obtained by molecular mapping are shown on a personal computer monitor. The scan steps of x and y axes were both 2.5 mm, and the photon-counting time per mapping point was 0.5 s. We carried out molecular mapping using the X-ray camera, and Kα photons from cerium and gadolinium molecules were produced from cancerous regions in nude mice.
Fabrication of Fe3O4@CuO core-shell from MOF based materials and its antibacterial activity
NASA Astrophysics Data System (ADS)
Rajabi, S. K.; Sohrabnezhad, Sh.; Ghafourian, S.
2016-12-01
Magnetic Fe3O4@CuO nanocomposite with a core/shell structure was successfully synthesized via direct calcinations of magnetic Fe3O4@HKUST-1 in air atmosphere. The morphology, structure, magnetic and porous properties of the as-synthesized nano composites were characterized by using scanning electron microscope (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), and vibration sample magnetometer (VSM). The results showed that the nanocomposite material included a Fe3O4 core and a CuO shell. The Fe3O4@CuO core-shell can be separated easily from the medium by a small magnet. The antibacterial activity of Fe3O4-CuO core-shell was investigated against gram-positive and gram-negative bacteria. A new mechanism was proposed for inactivation of bacteria over the prepared sample. It was demonstrated that the core-shell exhibit recyclable antibacterial activity, acting as an ideal long-acting antibacterial agent.
Chemical mapping of paleontological and archeological artifacts with synchrotron X-rays.
Bergmann, Uwe; Manning, Phillip L; Wogelius, Roy A
2012-01-01
The application of the recently developed synchrotron rapid scanning X-ray fluorescence (SRS-XRF) technique to the mapping of large objects is the focus of this review. We discuss the advantages of SRS-XRF over traditional systems and the use of other synchrotron radiation (SR) techniques to provide corroborating spectroscopic and diffraction analyses during the same analytical session. After reviewing routine techniques used to analyze precious specimens, we present several case studies that show how SR-based methods have been successfully applied in archeology and paleontology. For example, SRS-XRF imaging of a seventh-century Qur'ān palimpsest and an overpainted original opera score from Luigi Cherubini is described. We also review the recent discovery of soft-tissue residue in fossils of Archaeopteryx and an ancient reptile, as well as work that has successfully resolved the remnants of pigment in Confuciusornis sanctus, a 120-million-year-old fossil of the oldest documented bird with a fully derived avian beak.
Liu, Zhe-Peng; Cui, Lei; Yu, Deng-Guang; Zhao, Zhuan-Xia; Chen, Lan
2014-01-01
A novel structural solid dispersion (SD) taking the form of core-shell microparticles for poorly water-soluble drugs is reported for the first time. Using polyvinylpyrrolidone (PVP) as a hydrophilic polymer matrix, the SDs were fabricated using coaxial electrospraying (characterized by an epoxy-coated concentric spray head), although the core fluids were unprocessable using one-fluid electrospraying. Through manipulating the flow rates of the core drug-loaded solutions, two types of core-shell microparticles with tunable drug contents were prepared. They had average diameters of 1.36±0.67 and 1.74±0.58 μm, and were essentially a combination of nanocomposites with the active ingredient acyclovir (ACY) distributed in the inner core, and the sweeter sucralose and transmembrane enhancer sodium dodecyl sulfate localized in the outer shell. Differential scanning calorimetry and X-ray diffraction results demonstrated that ACY, sodium dodecyl sulfate, and sucralose were well distributed in the PVP matrix in an amorphous state because of favorable second-order interactions. In vitro dissolution and permeation studies showed that the core-shell microparticle SDs rapidly freed ACY within 1 minute and promoted nearly eightfold increases in permeation rate across the sublingual mucosa compared with raw ACY powders.
The influence of pore structure parameters on the digital core recovery degree
NASA Astrophysics Data System (ADS)
Xia, Huifen; Zhao, Ling; Sun, Yanyu; Yuan, Shi
2017-05-01
Constructing digital core in the research of water flooding or polymer flooding oil displacement efficiency has its unique advantage. Using mercury injection experiment measured pore throat size distribution frequency, coordination number measured by CT scanning method and imbibition displacement method is used to measure the wettability of the data, on the basis of considering pore throat ratio, wettability, using the principle of adaptive porosity, on the basis of fitting the permeability to complete the construction of digital core. The results show that the model of throat distribution is concentrated water flooding recovery degree is higher, and distribution is more decentralized model polymer flooding recovery degree is higher. Around the same number of PV in poly, coordination number model of water flooding and polymer flooding recovery degree is higher.
Tank 241-AP-105, cores 208, 209 and 210, analytical results for the final report
DOE Office of Scientific and Technical Information (OSTI.GOV)
Nuzum, J.L.
1997-10-24
This document is the final laboratory report for Tank 241-AP-105. Push mode core segments were removed from Risers 24 and 28 between July 2, 1997, and July 14, 1997. Segments were received and extruded at 222-S Laboratory. Analyses were performed in accordance with Tank 241-AP-105 Push Mode Core Sampling and Analysis Plan (TSAP) (Hu, 1997) and Tank Safety Screening Data Quality Objective (DQO) (Dukelow, et al., 1995). None of the subsamples submitted for total alpha activity (AT), differential scanning calorimetry (DSC) analysis, or total organic carbon (TOC) analysis exceeded the notification limits as stated in TSAP and DQO. The statisticalmore » results of the 95% confidence interval on the mean calculations are provided by the Tank Waste Remediation Systems Technical Basis Group, and are not considered in this report. Appearance and Sample Handling Two cores, each consisting of four segments, were expected from Tank 241-AP-105. Three cores were sampled, and complete cores were not obtained. TSAP states core samples should be transported to the laboratory within three calendar days from the time each segment is removed from the tank. This requirement was not met for all cores. Attachment 1 illustrates subsamples generated in the laboratory for analysis and identifies their sources. This reference also relates tank farm identification numbers to their corresponding 222-S Laboratory sample numbers.« less
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ophus, Colin; Ciston, Jim; Nelson, Chris T.
Unwanted motion of the probe with respect to the sample is a ubiquitous problem in scanning probe and scanning transmission electron microscopies, causing both linear and nonlinear artifacts in experimental images. We have designed a procedure to correct these artifacts by using orthogonal scan pairs to align each measurement line-by-line along the slow scan direction, by fitting contrast variation along the lines. We demonstrate the accuracy of our algorithm on both synthetic and experimental data and provide an implementation of our method.
Ophus, Colin; Ciston, Jim; Nelson, Chris T.
2015-12-10
Unwanted motion of the probe with respect to the sample is a ubiquitous problem in scanning probe and scanning transmission electron microscopies, causing both linear and nonlinear artifacts in experimental images. We have designed a procedure to correct these artifacts by using orthogonal scan pairs to align each measurement line-by-line along the slow scan direction, by fitting contrast variation along the lines. We demonstrate the accuracy of our algorithm on both synthetic and experimental data and provide an implementation of our method.
NASA Astrophysics Data System (ADS)
Li, Huijie; Meng, Fanming; Gong, Jinfeng; Fan, Zhenghua; Qin, Rui
2018-03-01
CeO2 nanospheres with the core-shell nanostructure have been successfully synthesized by a template-free hydrothermal method. The structures, morphologies and optical properties of core-shell CeO2 nanospheres were analyzed by X-ray diffraction (XRD), TG, Fourier transform infrared spectroscopy, XRD, EDS, SAED, scanning electron microscopy and transmission electron microscopy, UV-Vis diffuse reflectance spectra, Raman analyses. The degradation efficiencies of core-shell CeO2 nanospheres for methyl orange were as high as 93.49, 95.67 and 98.28% within 160 min, and the rates of photo degradation of methyl orange by core-shell CeO2 nanospheres under UV-light were 0.01693, 0.01782 and 0.02375 min-1. Methyl orange was degraded in photocatalytic oxidation processes, which mainly gave the credit to a large number of reactive species including h+, surface superoxide species ·O2 -, and ·OH radicals. The core-shell structure, small crystallite size and the conversion between Ce3+ and Ce4+ of CeO2 nanospheres were of importance for its catalytic activity. These results demonstrated the possibility of improving the efficient catalysts of the earth abundant CeO2 catalysts.
NASA Astrophysics Data System (ADS)
Jimenez-Moreno, Gonzalo; Camuera, Jon; Ramos-Roman, Maria J.; Toney, Jaime L.; Anderson, R. Scott; Jimenez-Espejo, Francisco J.; Kaufman, Darrell; Bright, Jordon; Webster, Cole
2017-04-01
Long paleoenvironmental records are necessary in order to understand recurrent climatic or paleoenvironmental changes occurring with a certain periodicity (i.e., glacial-interglacial cycles). In this respect, the Padul peat bog has one of the best available records of Pleistocene sediments in semiarid Southern Europe. The sedimentary sequence is more than 100 m thick and has been used to study palaeoenvironmental change for the past ca. 1 Ma. Since the 1960s several cores have already been taken from this basin showing oscillations in many proxies (pollen, organic geochemistry and sedimentation) related with paleoclimatic and paleohydrological changes. However, a more detailed and higher resolution study, using new dating and analytical techniques (AMS 14C, AAR, continuous XRF-scanning, high-resolution pollen analysis and geochemistry), needs to be done in such an interesting site. Here we present preliminary paleoenvironmental data from a new sediment core, Padul-15-05, which shows significant changes in the environment and lake sedimentation, probably related with glacial-interglacial climate dynamics during the past ca. 300,000 years. These data confirm that orbital- as well as suborbital-scale variability (i.e., Heinrich, D-O events) are recorded in the studied core. This unique record thus has very high potential for paleoenvironmental and paleoclimatic reconstructions for, at least, the two last climatic cycles in this semiarid Mediterranean area.
34. DESPATCH CORE OVENS, GREY IRON FOUNDRY CORE ROOM, BAKES ...
34. DESPATCH CORE OVENS, GREY IRON FOUNDRY CORE ROOM, BAKES CORES THAT ARE NOT MADE ON HEATED OR COLD BOX CORE MACHINES, TO SET BINDING AGENTS MIXED WITH THE SAND CREATING CORES HARD ENOUGH TO WITHSTAND THE FLOW OF MOLTEN IRON INSIDE A MOLD. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL
Field-portable-XRF reveals the ubiquity of antimony in plastic consumer products.
Turner, Andrew; Filella, Montserrat
2017-04-15
Very little systematic information exists on the occurrence and concentrations of antimony (Sb) in consumer products. In this study, a Niton XL3t field-portable-X-ray fluorescence (FP-XRF) spectrometer was deployed in situ and in the laboratory to provide quantitative information on Sb dissipated in plastic items and fixtures (including rubber, textile and foamed materials) from the domestic, school, vehicular and office settings. The metalloid was detected in 18% of over 800 measurements performed, with concentrations ranging from about 60 to 60,000μgg -1 . The highest concentrations were encountered in white, electronic casings and in association with similar concentrations of Br, consistent with the use of antimony oxides (e.g. Sb 2 O 3 ) as synergistic flame retardants. Concentrations above 1000μgg -1 , and with or without Br, were also encountered in paints, piping and hosing, adhesives, whiteboards, Christmas decorations, Lego blocks, document carriers, garden furniture, upholstered products and interior panels of private motor vehicles. Lower concentrations of Sb were encountered in a wide variety of items but its presence (without Br) in food tray packaging, single-use drinks bottles, straws and small toys were of greatest concern from a human health perspective. While the latter observations are consistent with the use of antimony compounds as catalysts in the production of polyethylene terephthalate, co-association of Sb and Br in many products not requiring flame retardancy suggests that electronic casings are widely recycled. Further research is required into the mobility of Sb when dissipated in new, recycled and aged polymeric materials. Copyright © 2017 Elsevier B.V. All rights reserved.
Enhanced Ethanol Gas Sensing Properties of SnO2-Core/ZnO-Shell Nanostructures
Tharsika, T.; Haseeb, A. S. M. A.; Akbar, Sheikh A.; Sabri, Mohd Faizul Mohd; Hoong, Wong Yew
2014-01-01
An inexpensive single-step carbon-assisted thermal evaporation method for the growth of SnO2-core/ZnO-shell nanostructures is described, and the ethanol sensing properties are presented. The structure and phases of the grown nanostructures are investigated by field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques. XRD analysis indicates that the core-shell nanostructures have good crystallinity. At a lower growth duration of 15 min, only SnO2 nanowires with a rectangular cross-section are observed, while the ZnO shell is observed when the growth time is increased to 30 min. Core-shell hierarchical nanostructures are present for a growth time exceeding 60 min. The growth mechanism for SnO2-core/ZnO-shell nanowires and hierarchical nanostructures are also discussed. The sensitivity of the synthesized SnO2-core/ZnO-shell nanostructures towards ethanol sensing is investigated. Results show that the SnO2-core/ZnO-shell nanostructures deposited at 90 min exhibit enhanced sensitivity to ethanol. The sensitivity of SnO2-core/ZnO-shell nanostructures towards 20 ppm ethanol gas at 400 °C is about ∼5-times that of SnO2 nanowires. This improvement in ethanol gas response is attributed to high active sensing sites and the synergistic effect of the encapsulation of SnO2 by ZnO nanostructures. PMID:25116903
Core Formation Process and Light Elements in the Planetary Core
NASA Astrophysics Data System (ADS)
Ohtani, E.; Sakairi, T.; Watanabe, K.; Kamada, S.; Sakamaki, T.; Hirao, N.
2015-12-01
Si, O, and S are major candidates for light elements in the planetary core. In the early stage of the planetary formation, the core formation started by percolation of the metallic liquid though silicate matrix because Fe-S-O and Fe-S-Si eutectic temperatures are significantly lower than the solidus of the silicates. Therefore, in the early stage of accretion of the planets, the eutectic liquid with S enrichment was formed and separated into the core by percolation. The major light element in the core at this stage will be sulfur. The internal pressure and temperature increased with the growth of the planets, and the metal component depleted in S was molten. The metallic melt contained both Si and O at high pressure in the deep magma ocean in the later stage. Thus, the core contains S, Si, and O in this stage of core formation. Partitioning experiments between solid and liquid metals indicate that S is partitioned into the liquid metal, whereas O is weakly into the liquid. Partitioning of Si changes with the metallic iron phases, i.e., fcc iron-alloy coexisting with the metallic liquid below 30 GPa is depleted in Si. Whereas hcp-Fe alloy above 30 GPa coexisting with the liquid favors Si. This contrast of Si partitioning provides remarkable difference in compositions of the solid inner core and liquid outer core among different terrestrial planets. Our melting experiments of the Fe-S-Si and Fe-O-S systems at high pressure indicate the core-adiabats in small planets, Mercury and Mars, are greater than the slope of the solidus and liquidus curves of these systems. Thus, in these planets, the core crystallized at the top of the liquid core and 'snowing core' formation occurred during crystallization. The solid inner core is depleted in both Si and S whereas the liquid outer core is relatively enriched in Si and S in these planets. On the other hand, the core adiabats in large planets, Earth and Venus, are smaller than the solidus and liquidus curves of the systems. The
Vibration mode and vibration shape under excitation of a three phase model transformer core
NASA Astrophysics Data System (ADS)
Okabe, Seiji; Ishigaki, Yusuke; Omura, Takeshi
2018-04-01
Structural vibration characteristics and vibration shapes under three-phase excitation of a archetype transformer core were investigated to consider their influences on transformer noise. Acoustic noise and vibration behavior were measured in a three-limb model transformer core. Experimental modal analysis by impact test was performed. The vibration shapes were measured by a laser scanning vibrometer at different exciting frequencies. Vibration amplitude of the core in out-of-plane direction were relatively larger than those in other two in-plane directions. It was consistent with the result that the frequency response function of the core in out-of-plane direction was larger by about 20 dB or more than those in in-plane directions. There were many vibration modes having bending deformation of limbs in out-of-plane direction. The vibration shapes of the core when excited at 50 Hz and 60 Hz were almost the same because the fundamental frequencies of the vibration were not close to the resonance frequencies. When excitation frequency was 69 Hz which was half of one of the resonance frequencies, the vibration shape changed to the one similar to the resonance vibration mode. Existence of many vibration modes in out-of-plane direction of the core was presumed to be a reason why frequency characteristics of magnetostriction and transformer noise do not coincide.
Special raster scanning for reduction of charging effects in scanning electron microscopy.
Suzuki, Kazuhiko; Oho, Eisaku
2014-01-01
A special raster scanning (SRS) method for reduction of charging effects is developed for the field of SEM. Both a conventional fast scan (horizontal direction) and an unusual scan (vertical direction) are adopted for acquiring raw data consisting of many sub-images. These data are converted to a proper SEM image using digital image processing techniques. About sharpness of the image and reduction of charging effects, the SRS is compared with the conventional fast scan (with frame-averaging) and the conventional slow scan. Experimental results show the effectiveness of SRS images. By a successful combination of the proposed scanning method and low accelerating voltage (LV)-SEMs, it is expected that higher-quality SEM images can be more easily acquired by the considerable reduction of charging effects, while maintaining the resolution. © 2013 Wiley Periodicals, Inc.
Lidar arc scan uncertainty reduction through scanning geometry optimization
NASA Astrophysics Data System (ADS)
Wang, H.; Barthelmie, R. J.; Pryor, S. C.; Brown, G.
2015-10-01
Doppler lidars are frequently operated in a mode referred to as arc scans, wherein the lidar beam scans across a sector with a fixed elevation angle and the resulting measurements are used to derive an estimate of the n minute horizontal mean wind velocity (speed and direction). Previous studies have shown that the uncertainty in the measured wind speed originates from turbulent wind fluctuations and depends on the scan geometry (the arc span and the arc orientation). This paper is designed to provide guidance on optimal scan geometries for two key applications in the wind energy industry: wind turbine power performance analysis and annual energy production. We present a quantitative analysis of the retrieved wind speed uncertainty derived using a theoretical model with the assumption of isotropic and frozen turbulence, and observations from three sites that are onshore with flat terrain, onshore with complex terrain and offshore, respectively. The results from both the theoretical model and observations show that the uncertainty is scaled with the turbulence intensity such that the relative standard error on the 10 min mean wind speed is about 30 % of the turbulence intensity. The uncertainty in both retrieved wind speeds and derived wind energy production estimates can be reduced by aligning lidar beams with the dominant wind direction, increasing the arc span and lowering the number of beams per arc scan. Large arc spans should be used at sites with high turbulence intensity and/or large wind direction variation when arc scans are used for wind resource assessment.
How cores grow by pebble accretion. I. Direct core growth
NASA Astrophysics Data System (ADS)
Brouwers, M. G.; Vazan, A.; Ormel, C. W.
2018-03-01
Context. Planet formation by pebble accretion is an alternative to planetesimal-driven core accretion. In this scenario, planets grow by the accretion of cm- to m-sized pebbles instead of km-sized planetesimals. One of the main differences with planetesimal-driven core accretion is the increased thermal ablation experienced by pebbles. This can provide early enrichment to the planet's envelope, which influences its subsequent evolution and changes the process of core growth. Aims: We aim to predict core masses and envelope compositions of planets that form by pebble accretion and compare mass deposition of pebbles to planetesimals. Specifically, we calculate the core mass where pebbles completely evaporate and are absorbed before reaching the core, which signifies the end of direct core growth. Methods: We model the early growth of a protoplanet by calculating the structure of its envelope, taking into account the fate of impacting pebbles or planetesimals. The region where high-Z material can exist in vapor form is determined by the temperature-dependent vapor pressure. We include enrichment effects by locally modifying the mean molecular weight of the envelope. Results: In the pebble case, three phases of core growth can be identified. In the first phase (Mcore < 0.23-0.39 M⊕), pebbles impact the core without significant ablation. During the second phase (Mcore < 0.5M⊕), ablation becomes increasingly severe. A layer of high-Z vapor starts to form around the core that absorbs a small fraction of the ablated mass. The rest of the material either rains out to the core or instead mixes outwards, slowing core growth. In the third phase (Mcore > 0.5M⊕), the high-Z inner region expands outwards, absorbing an increasing fraction of the ablated material as vapor. Rainout ends before the core mass reaches 0.6 M⊕, terminating direct core growth. In the case of icy H2O pebbles, this happens before 0.1 M⊕. Conclusions: Our results indicate that pebble accretion can
Apparatus for controlling the scan width of a scanning laser beam
Johnson, Gary W.
1996-01-01
Swept-wavelength lasers are often used in absorption spectroscopy applications. In experiments where high accuracy is required, it is desirable to continuously monitor and control the range of wavelengths scanned (the scan width). A system has been demonstrated whereby the scan width of a swept ring-dye laser, or semiconductor diode laser, can be measured and controlled in real-time with a resolution better than 0.1%. Scan linearity, or conformity to a nonlinear scan waveform, can be measured and controlled. The system of the invention consists of a Fabry-Perot interferometer, three CAMAC interface modules, and a microcomputer running a simple analysis and proportional-integral control algorithm. With additional modules, multiple lasers can be simultaneously controlled. The invention also includes an embodiment implemented on an ordinary PC with a multifunction plug-in board.
NASA Astrophysics Data System (ADS)
Nace, T.; Baker, P. A.; Dwyer, G. S.; Silva, C. G.; Hollander, D. J.; Rigsby, C. A.; Giosan, L.; Burns, S. J.
2011-12-01
Paleoclimate/paleoceanographic reconstructions of the Amazon Basin, Brazilian Nordeste, and western equatorial Atlantic have been undertaken on two new sediment cores located on the Brazilian continental slope (Core CDH-5 at 1708 mbsl, 4N, 48W, 32m long, ~30 ka record; Core CDH-86 at 3708 mbsl, 0N/S, 44W, 30m long, ~100ka record). High-resolution XRF analyses of Fe, Ti, and Ca are used to define the paleohydrologic history of the adjacent continent at both sites. Large and abrupt excursions of Ti/Ca ratios are observed in both cores, but are significantly better defined in the southern core, representative of Nordeste conditions. In this core there are a total of 9 Ti/Ca excursions, the oldest recovered dating to ~98ka. These excursions correlate well with Heinrich events from the North Atlantic. High-resolution stable oxygen isotopic analysis and Mg/Ca paleothermometry undertaken on the near-surface-dwelling planktic foraminiferal species Globierinoides ruber provide a picture of paleoceanographic forcings in the western equatorial Atlantic. The northern and southern cores respectively exhibit rapid warming of ~3C and ~3.5C between the last glacial maximum and the early Holocene. Furthermore, in almost all cases, during the last glacial stage, there was a 0.5C to 2C warming of the western equatorial Atlantic during the periods of high Ti/Ca ratios that correlate with Heinrich events. Thus, as observed in some previous studies, the western equatorial Atlantic was warm and the adjacent southern tropical continent was wet at the same time that the high-latitude North Atlantic was cold. The largely accepted paradigm is that Northern hemisphere cold events result in a southward migration of the Intertropical Convergence Zone (ITCZ), contributing to drier conditions at the northern extent of the ITCZ annual range (Cariaco Basin) and increased precipitation in the southern tropics of South America. The ITCZ appears to have been influenced by millennial variability of
NASA Astrophysics Data System (ADS)
Yan, Yi; Ngo, Khai D. T.; Hou, Dongbin; Mu, Mingkai; Mei, Yunhui; Lu, Guo-Quan
2015-10-01
In an effort to find a magnetic material for making low-loss magnetic components for high-power-density converters, we investigated the magnetic core-loss characteristics of a commercial NiCuZn ferrite (LSF 50) at 5 MHz as a function of the sintering temperature of the ferrite powder. The ferrite powder was compacted into toroid cores and then sintered at 850°C, 900°C, 950°C, 1000°C, and 1050°C for 2 h. The sintered densities of the cores increased at higher sintering temperatures. The magnetic properties of the sintered cores—complex permeability and core-loss density—were measured. We found that both the real and imaginary parts of the relative permeability increased with sintering temperature. The core-loss results at 5 MHz showed that the cores sintered at 950°C and 1000°C had the lowest core-loss densities, being two to three times lower than that of a commercial NiZn ferrite (4F1) core. Microstructures of the sintered cores were examined by scanning electron microscopy; the grains grew significantly at higher sintering temperatures.
23. CORE WORKER OPERATING A COREBLOWER THAT PNEUMATICALLY FILLED CORE ...
23. CORE WORKER OPERATING A CORE-BLOWER THAT PNEUMATICALLY FILLED CORE BOXES WITH RESIGN IMPREGNATED SAND AND CREATED A CORE THAT THEN REQUIRED BAKING, CA. 1950. - Stockham Pipe & Fittings Company, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL
NASA Astrophysics Data System (ADS)
Rajamanickam, N.; Jayakumar, K.; Ramachandran, K.
2018-04-01
Core/shell BaSnO3/ZnO (BS-ZO) nanostructures were prepared by oxalate precipitation method and wet-chemical method. BaSnO3 (BSO) cubic perovskite structure and ZnO hexagonal wurtzite structure were confirmed by X-ray diffraction (XRD). The crystallite sizes is 23 nm, 29 nm and 27 nm for BSO, ZnO and BS-ZO, respectively. Chunk-shape and cuboids morphology observed from scanning electron microscopy (SEM) analysis. The magnetic properties were studied by VSM for bare and core-shell nano systems and the room temperature ferromagnetism observed for core-shell nanostructures. The BSO/ZnO shows enhanced coercivity and saturated magnetization as compared with BSO and ZnO nanostructures.
NASA Astrophysics Data System (ADS)
Zhang, Zhaohui; Liu, Li; Li, Hui; Yao, Shouzhuo
2009-09-01
A novel core-shell molecularly imprinting microspheres (MIMs) with trans-resveratrol as the template molecule; acrylamide (AA) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker, was prepared based on SiO 2 microspheres with surface imprinting technique. These core-shell trans-resveratrol imprinted microspheres were characterized by infrared spectra (IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and high performance liquid chromatography (HPLC). The results showed that these core-shell imprinted microspheres, which take on perfect spherical shape with average shell thickness of 150 nm, exhibit especially selective recognition for trans-resveratrol. These imprinted microspheres were applied as solid-phase extraction materials for selective extraction of trans-resveratrol from giant knotweed extracting solution successfully.
ERIC Educational Resources Information Center
Carmichael, Sheila Byrd; Wilson, W. Stephen; Finn, Chester E., Jr.; Winkler, Amber M.; Palmieri, Stafford
2009-01-01
Subject-matter experts reviewed the content, rigor, and clarity of the first public drafts of the "Common Core" standards released in September 2009 by the Common Core State Standards Initiative (CCSSI) of the National Governors Association and Council of Chief State School Officers. Using the same criteria, the same experts also…
All zinc-blende GaAs/(Ga,Mn)As core-shell nanowires with ferromagnetic ordering.
Yu, Xuezhe; Wang, Hailong; Pan, Dong; Zhao, Jianhua; Misuraca, Jennifer; von Molnár, Stephan; Xiong, Peng
2013-04-10
Combining self-catalyzed vapor-liquid-solid growth of GaAs nanowires and low-temperature molecular-beam epitaxy of (Ga,Mn)As, we successfully synthesized all zinc-blende (ZB) GaAs/(Ga,Mn)As core-shell nanowires on Si(111) substrates. The ZB GaAs nanowire cores are first fabricated at high temperature by utilizing the Ga droplets as the catalyst and controlling the triple phase line nucleation, then the (Ga,Mn)As shells are epitaxially grown on the side facets of the GaAs core at low temperature. The growth window for the pure phase GaAs/(Ga,Mn)As core-shell nanowires is found to be very narrow. Both high-resolution transmission electron microscopy and scanning electron microscopy observations confirm that all-ZB GaAs/(Ga,Mn)As core-shell nanowires with smooth side surface are obtained when the Mn concentration is not more than 2% and the growth temperature is 245 °C or below. Magnetic measurements with different applied field directions provide strong evidence for ferromagnetic ordering in the all-ZB GaAs/(Ga,Mn)As nanowires. The hybrid nanowires offer an attractive platform to explore spin transport and device concepts in fully epitaxial all-semiconductor nanospintronic structures.
Novel Organically Modified Core-Shell Clay for Epoxy Composites—“SOBM Filler 1”
Iheaturu, Nnamdi Chibuike; Madufor, Innocent Chimezie
2014-01-01
Preparation of a novel organically modified clay from spent oil base drilling mud (SOBM) that could serve as core-shell clay filler for polymers is herein reported. Due to the hydrophilic nature of clay, its compatibility with polymer matrix was made possible through modification of the surface of the core clay sample with 3-aminopropyltriethoxysilane (3-APTES) compound prior to its use. Fourier transform infrared (FT-IR) spectroscopy was used to characterize clay surface modification. Electron dispersive X-ray diffraction (EDX) and scanning electron microscopy (SEM) were used to expose filler chemical composition and morphology, while electrophoresis measurement was used to examine level of filler dispersion. Results show an agglomerated core clay powder after high temperature treatment, while EDX analysis shows that the organically modified clay is composed of chemical inhomogeneities, wherein elemental compositions in weight percent vary from one point to the other in a probe of two points. Micrographs of the 3-APTES coupled SOBM core-shell clay filler clearly show cloudy appearance, while FT-IR indicates 25% and 5% increases in fundamental vibrations band at 1014 cm−1 and 1435 cm−1, respectively. Furthermore, 3-APTES coupled core-shell clay was used to prepare epoxy composites and tested for mechanical properties. PMID:27355022
NASA Astrophysics Data System (ADS)
Büdel, Christian; Hoelzmann, Philipp; Wennrich, Volker; Majid Padashi, Sajed; Baumhauer, Roland
2015-04-01
The study yields a first characterization and correlation of the end-Pleistocene to Holocene sediment archive of playa and playa lake deposits in the Damghan Basin, northern Iran. The Basin sediments are deposited since Mio- and Pliocene, which is valid for the connected alluvial fans, too. These are covering the area between the playa and mountains and while prograding from the mountain ranges they deliver gravels and fine-sediments to the basins sink. The processes on the studied alluvial apron are described and dated already and can be explained in seven morphodynamic phases, which are linked to a general lake level high-stand in north-east Iran at about 8000-9000 years ago. If and how these phases are passed on from the alluvial record down to the playa sediment record is aim of this study. Today the salt pans margins are highly affected by salt tectonic drifting and access was suboptimal. Only here drilling could be performed through about 280 centimeters of salt-crust unfrequently intercalated with loamy layers. For yielding undisturbed playa sediment records sampling was performed with inliner-tubes deployed in a piston corer (Kullenberg type). Thus at two different drilling sites in summation seven cores could be taken, down to a maximum depth of 129 cm and 1000 cm. Back in Germany the cores had been opened and initially described, photographed and optically scanned with a core logger. Regarding future studies, the aim was a best possible comprehensive documentation of the cores. Therefore basically grainsize measurements (laser diffraction), multi element analyses (XRF, ICP-OES, titrimetry) and mineralogical measurements (XRD) had been deployed on samples taken from every single previously identified layer. Continuous elemental data was secured by use of a XRF-scanning core logger. The sedimentological description together with laboratory element analyses shows saline conditions in the first three meters coincide with general coarser grain sizes. The next
NASA Astrophysics Data System (ADS)
Francke, Alexander; Wagner, Bernd; Krastel, Sebastian; Lindhorst, Katja; Mantke, Nicole; Klinghardt, Dorothea
2014-05-01
Lake Ohrid, located at the border of Macedonia and Albania is about 30 km long, 15 km wide and up to 290 m deep. Formed within a tectonic graben, Lake Ohrid is considered to be the oldest lake in Europe. The ICDP SCOPSCO (Scientific Collaboration of Past Speciation Conditions in Lake Ohrid) deep drilling campaign at Lake Ohrid in spring 2013 aimed (a) to obtain more precise information about the age and origin of the lake, (b) to unravel the seismotectonic history of the lake area including effects of major earthquakes and associated mass wasting events, (c) to obtain a continuous record containing information on volcanic activities and climate changes in the central northern Mediterranean region, and (d) to better understand the impact of major geological/environmental events on general evolutionary patterns and shaping an extraordinary degree of endemic biodiversity as a matter of global significance. Drilling was carried out by DOSECC (Salt Lake City, USA) using the DLDS (Deep Lake Drilling System) with a hydraulic piston corer for surface sediments and rotation drilling for harder, deeper sediments. Overall, about 2,100 m of sediment were recovered from 4 drill sites. At the "DEEP" site in the center of the lake, seismic data indicated a maximum sediment fill of ca. 700 m, of which the uppermost 568 m sediment were recovered. Initial data from core catcher samples and on-site susceptibility measurements indicate that the sediment sequence covers more than 1.2 million years and provides a continuous archive of environmental and climatological variability in the area. Currently, core opening, core description, XRF and MSCL -scanning, core correlation, and sub-sampling of the sediment cores from the "DEEP" site is conducted at the University of Cologne. High-resolution geochemical data obtained from XRF-scanning imply that the sediments from the "DEEP" site are highly sensitive to climate and environmental variations in the Balkan area over the last few glacial
Polycrystalline silicon carbide dopant profiles obtained through a scanning nano-Schottky contact
DOE Office of Scientific and Technical Information (OSTI.GOV)
Golt, M. C.; Strawhecker, K. E.; Bratcher, M. S.
2016-07-14
The unique thermo-electro-mechanical properties of polycrystalline silicon carbide (poly-SiC) make it a desirable candidate for structural and electronic materials for operation in extreme environments. Necessitated by the need to understand how processing additives influence poly-SiC structure and electrical properties, the distribution of lattice defects and impurities across a specimen of hot-pressed 6H poly-SiC processed with p-type additives was visualized with high spatial resolution using a conductive atomic force microscopy approach in which a contact forming a nano-Schottky interface is scanned across the sample. The results reveal very intricate structures within poly-SiC, with each grain having a complex core-rim structure. Thismore » complexity results from the influence the additives have on the evolution of the microstructure during processing. It was found that the highest conductivities localized at rims as well as at the interface between the rim and the core. The conductivity of the cores is less than the conductivity of the rims due to a lower concentration of dopant. Analysis of the observed conductivities and current-voltage curves is presented in the context of nano-Schottky contact regimes where the conventional understanding of charge transport to diode operation is no longer valid.« less
Polycrystalline silicon carbide dopant profiles obtained through a scanning nano-Schottky contact
NASA Astrophysics Data System (ADS)
Golt, M. C.; Strawhecker, K. E.; Bratcher, M. S.; Shanholtz, E. R.
2016-07-01
The unique thermo-electro-mechanical properties of polycrystalline silicon carbide (poly-SiC) make it a desirable candidate for structural and electronic materials for operation in extreme environments. Necessitated by the need to understand how processing additives influence poly-SiC structure and electrical properties, the distribution of lattice defects and impurities across a specimen of hot-pressed 6H poly-SiC processed with p-type additives was visualized with high spatial resolution using a conductive atomic force microscopy approach in which a contact forming a nano-Schottky interface is scanned across the sample. The results reveal very intricate structures within poly-SiC, with each grain having a complex core-rim structure. This complexity results from the influence the additives have on the evolution of the microstructure during processing. It was found that the highest conductivities localized at rims as well as at the interface between the rim and the core. The conductivity of the cores is less than the conductivity of the rims due to a lower concentration of dopant. Analysis of the observed conductivities and current-voltage curves is presented in the context of nano-Schottky contact regimes where the conventional understanding of charge transport to diode operation is no longer valid.
Scan path entropy and arrow plots: capturing scanning behavior of multiple observers
Hooge, Ignace; Camps, Guido
2013-01-01
Designers of visual communication material want their material to attract and retain attention. In marketing research, heat maps, dwell time, and time to AOI first hit are often used as evaluation parameters. Here we present two additional measures (1) “scan path entropy” to quantify gaze guidance and (2) the “arrow plot” to visualize the average scan path. Both are based on string representations of scan paths. The latter also incorporates transition matrices and time required for 50% of the observers to first hit AOIs (T50). The new measures were tested in an eye tracking study (48 observers, 39 advertisements). Scan path entropy is a sensible measure for gaze guidance and the new visualization method reveals aspects of the average scan path and gives a better indication in what order global scanning takes place. PMID:24399993
NASA Astrophysics Data System (ADS)
Krause, Thilo; Hanke, Michael; Nicolai, Lars; Cheng, Zongzhe; Niehle, Michael; Trampert, Achim; Kahnt, Maik; Falkenberg, Gerald; Schroer, Christian G.; Hartmann, Jana; Zhou, Hao; Wehmann, Hergo-Heinrich; Waag, Andreas
2017-02-01
Nanofocus x-ray diffraction is used to investigate the structure and local strain field of an isolated (In ,Ga )N /GaN core-shell microrod. Because the high spatial resolution of the x-ray beam is only 80 ×90 nm2, we are able to investigate several distinct volumes on one individual side facet. Here, we find a drastic increase in thickness of the outer GaN shell along the rod height. Additionally, we performed high-angle annular dark-field scanning-transmission-electron-microscopy measurements on several rods from the same sample showing that (In,Ga)N double-quantum-well and GaN barrier thicknesses also increase strongly along the height. Moreover, plastic relaxation is observed in the top part of the rod. Based on the experimentally obtained structural parameters, we simulate the strain-induced deformation using the finite-element method, which serves as the input for subsequent kinematic scattering simulations. The simulations reveal a significant increase of elastic in-plane relaxation along the rod height. However, at a certain height, the occurrence of plastic relaxation yields a decrease of the elastic strain. Because of the experimentally obtained structural input for the finite-element simulations, we can exclude unknown structural influences on the strain distribution, and we are able to translate the elastic relaxation into an indium concentration which increases by a factor of 4 from the bottom to the height where plastic relaxation occurs.
Apparatus for controlling the scan width of a scanning laser beam
Johnson, G.W.
1996-10-22
Swept-wavelength lasers are often used in absorption spectroscopy applications. In experiments where high accuracy is required, it is desirable to continuously monitor and control the range of wavelengths scanned (the scan width). A system has been demonstrated whereby the scan width of a swept ring-dye laser, or semiconductor diode laser, can be measured and controlled in real-time with a resolution better than 0.1%. Scan linearity, or conformity to a nonlinear scan waveform, can be measured and controlled. The system of the invention consists of a Fabry-Perot interferometer, three CAMAC interface modules, and a microcomputer running a simple analysis and proportional-integral control algorithm. With additional modules, multiple lasers can be simultaneously controlled. The invention also includes an embodiment implemented on an ordinary PC with a multifunction plug-in board. 8 figs.
Hybrid self-healing matrix using core-shell nanofibers and capsuleless microdroplets.
Lee, Min Wook; An, Seongpil; Lee, Changmin; Liou, Minho; Yarin, Alexander L; Yoon, Sam S
2014-07-09
In this work, we developed novel self-healing anticorrosive hierarchical coatings that consist of several components. Namely, as a skeleton we prepared a core-shell nanofiber mat electrospun from emulsions of cure material (dimethyl methylhydrogen siloxane) in a poly(acrylonitrile) (PAN) solution in dimethylformamide. In these nanofibers, cure is in the core, while PAN is in the shell. The skeleton deposited on a protected surface is encased in an epoxy-based matrix, which contains emulsified liquid droplets of dimethylvinyl-terminated dimethylsiloxane resin monomer. When such hierarchical coatings are damaged, cure is released from the nanofiber cores and the resin monomer, released from the damaged matrix, is polymerized in the presence of cure. This polymerization and solidification process takes about 1-2 days and eventually heals the damaged material when solid poly(dimethylsiloxane) resin is formed. The self-healing effect was demonstrated using an electrochemical analogue of the scanning vibrating electrode technique. Damaged samples were left for 2 days. After that, the electric current through a damaged coating was found to be negligibly small for the samples with self-healing properties. On the other hand, for the samples without self-healing properties, the electric current was significant.
NASA Technical Reports Server (NTRS)
Gheen, Darrell
2007-01-01
A tool makes a cut perpendicular to the cylindrical axis of a core hole at a predetermined depth to free the core at that depth. The tool does not damage the surrounding material from which the core was cut, and it operates within the core-hole kerf. Coring usually begins with use of a hole saw or a hollow cylindrical abrasive cutting tool to make an annular hole that leaves the core (sometimes called the plug ) in place. In this approach to coring as practiced heretofore, the core is removed forcibly in a manner chosen to shear the core, preferably at or near the greatest depth of the core hole. Unfortunately, such forcible removal often damages both the core and the surrounding material (see Figure 1). In an alternative prior approach, especially applicable to toxic or fragile material, a core is formed and freed by means of milling operations that generate much material waste. In contrast, the present tool eliminates the damage associated with the hole-saw approach and reduces the extent of milling operations (and, hence, reduces the waste) associated with the milling approach. The present tool (see Figure 2) includes an inner sleeve and an outer sleeve and resembles the hollow cylindrical tool used to cut the core hole. The sleeves are thin enough that this tool fits within the kerf of the core hole. The inner sleeve is attached to a shaft that, in turn, can be attached to a drill motor or handle for turning the tool. This tool also includes a cutting wire attached to the distal ends of both sleeves. The cutting wire is long enough that with sufficient relative rotation of the inner and outer sleeves, the wire can cut all the way to the center of the core. The tool is inserted in the kerf until its distal end is seated at the full depth. The inner sleeve is then turned. During turning, frictional drag on the outer core pulls the cutting wire into contact with the core. The cutting force of the wire against the core increases with the tension in the wire and
NASA Astrophysics Data System (ADS)
Yao, J.; Tian, D.; Sun, L.; Wen, L.
2017-12-01
Since Song and Richards [1996] first reported seismic evidence for temporal change of PKIKP wave (a compressional wave refracted in the inner core) and proposed inner core differential rotation as its explanation, it has generated enormous interests in the scientific community and the public, and has motivated many studies on the implications of the inner core differential rotation. However, since Wen [2006] reported seismic evidence for temporal change of PKiKP wave (a compressional wave reflected from the inner core boundary) that requires temporal change of inner core surface, both interpretations for the temporal change of inner core phases have existed, i.e., inner core rotation and temporal change of inner core surface. In this study, we discuss the issue of the interpretation of the observed temporal changes of those inner core phases and conclude that inner core differential rotation is not only not required but also in contradiction with three lines of seismic evidence from global repeating earthquakes. Firstly, inner core differential rotation provides an implausible explanation for a disappearing inner core scatterer between a doublet in South Sandwich Islands (SSI), which is located to be beneath northern Brazil based on PKIKP and PKiKP coda waves of the earlier event of the doublet. Secondly, temporal change of PKIKP and its coda waves among a cluster in SSI is inconsistent with the interpretation of inner core differential rotation, with one set of the data requiring inner core rotation and the other requiring non-rotation. Thirdly, it's not reasonable to invoke inner core differential rotation to explain travel time change of PKiKP waves in a very small time scale (several months), which is observed for repeating earthquakes in Middle America subduction zone. On the other hand, temporal change of inner core surface could provide a consistent explanation for all the observed temporal changes of PKIKP and PKiKP and their coda waves. We conclude that
Immersion ultrasonography: simultaneous A-scan and B-scan.
Coleman, D J; Dallow, R L; Smith, M E
1979-01-01
In eyes with opaque media, ophthalmic ultrasound provides a unique source of information that can dramatically affect the course of patient management. In addition, when an ocular abnormality can be visualized, ultrasonography provides information that supplements and complements other diagnostic testing. It provides documentation and differentiation of abnormal states, such as vitreous hemorrhage and intraocular tumor, as well as differentiation of orbital tumors from inflammatory causes of exophthalmos. Additional capabilities of ultrasound are biometric determinations for calculation of intraocular lens implant powers and drug-effectiveness studies. Maximal information is derived from ultrasonography when A-scan and B-scan techniques are employed simultaneously. Flexibility of electronics, variable-frequency transducers, and the use of several different manual scanning patterns aid in detection and interpretation of results. The immersion system of ultrasonography provides these features optimally.
Biocompatible core-shell magnetic nanoparticles for cancer treatment
NASA Astrophysics Data System (ADS)
Sharma, Amit; Qiang, You; Meyer, Daniel; Souza, Ryan; Mcconnaughoy, Alan; Muldoon, Leslie; Baer, Donald
2008-04-01
Nontoxic magnetic nanoparticles (MNPs) have expanded treatment delivery options in the medical world. With a size range from 2to200nm, MNPs can be compiled with most of the small cells and tissues in the living body. Monodispersive iron-iron oxide core-shell nanoparticles were prepared by our novel cluster deposition system. This unique method of preparing core-shell MNPs gives the nanoparticles a very high magnetic moment. We tested the nontoxicity and uptake of MNPs coated with/without dextrin by incubating them with rat LX-1 small cell lung cancer cells. Since core iron enhances the heating effect [L. Baker, Q. Zeing, W. Li, and S. Sullivan, J. Appl. Phys. 99, 08H106 (2006)], the rate of oxidation of iron nanoparticles was also tested in de-ionized water at a certain time interval. Both coated and noncoated MNPs were successfully uptaken by the cells, indicating that the nanoparticles were not toxic. The stability of MNPs was verified by x-ray diffraction scan after 0, 24, 48, 96, and 204h. Due to the high magnetic moment offered by MNPs produced in our laboratory, we predict that even at low applied external alternating field, the desired temperature could be reached in cancer cells in comparison to the commercially available nanoparticles. Moreover our MNPs do not require additional transfection agent, providing a cost effective means of treatment with significantly lower dosage in the body in comparison to commercially available nanoparticles.
Fabrication of Te@Au core-shell hybrids for efficient ethanol oxidation
NASA Astrophysics Data System (ADS)
Jin, Huile; Wang, Demeng; Zhao, Yuewu; Zhou, Huan; Wang, Shun; Wang, Jichang
2012-10-01
Using Au nanoparticles to catalyze the oxidation of alcohols has garnered increasing attention due to its potential application in direct alcohol fuel cells. In this research Te@Au core-shell hybrids were fabricated for the catalytic oxidation of ethanol, where the preparation procedure involved the initial production of Te crystals with different microstructures and the subsequent utilization of the Te crystal as a template and reducing agent for the production of Te@Au hybrids. The as-prepared core-shell hybrids were characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction techniques. Electrochemical measurements illustrate that the hybrids have great electrocatalytic activity and stability toward ethanol oxidation in alkaline media. The enhanced electrocatalytic property may be attributed to the cooperative effects between the metal and semiconductor and the presence of a large number of active sites on the hybrids surface.
Highly exothermic and superhydrophobic Mg/fluorocarbon core/shell nanoenergetic arrays.
Zhou, Xiang; Xu, Daguo; Yang, Guangcheng; Zhang, Qiaobao; Shen, Jinpeng; Lu, Jian; Zhang, Kaili
2014-07-09
Mg/fluorocarbon core/shell nanoenergetic arrays are prepared onto silicon substrate, with Mg nanorods as the core and fluorocarbon as the shell. Mg nanorods are deposited by the glancing angle deposition technique, and the fluorocarbon layer is then prepared as a shell to encase the Mg nanorods by the magnetron sputtering deposition process. Scanning electron microscopy and transmission electron microscopy show the core/shell structure of the Mg/fluorocarbon arrays. X-ray energy-dispersive spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy are used to characterize the structural composition of the Mg/fluorocarbon. It is found that the as-prepared fluorocarbon layer consists of shorter molecular chains compared to that of bulk polytetrafluoroethylene, which is proven beneficial to the low onset reaction temperature of Mg/fluorocarbon. Water contact angle test demonstrates the superhydrophobicity of the Mg/fluorocarbon arrays, and a static contact angle as high as 162° is achieved. Thermal analysis shows that the Mg/fluorocarbon material exhibits a very low onset reaction temperature of about 270 °C as well as an ultrahigh heat of reaction approaching 9 kJ/g. A preliminary combustion test reveals rapid combustion wave propagation, and a convective mechanism is adopted to explain the combustion behaviors.
Performance testing and results of the first Etec CORE-2564
NASA Astrophysics Data System (ADS)
Franks, C. Edward; Shikata, Asao; Baker, Catherine A.
1993-03-01
In order to be able to write 64 megabit DRAM reticles, to prepare to write 256 megabit DRAM reticles and in general to meet the current and next generation mask and reticle quality requirements, Hoya Micro Mask (HMM) installed in 1991 the first CORE-2564 Laser Reticle Writer from Etec Systems, Inc. The system was delivered as a CORE-2500XP and was subsequently upgraded to a 2564. The CORE (Custom Optical Reticle Engraver) system produces photomasks with an exposure strategy similar to that employed by an electron beam system, but it uses a laser beam to deliver the photoresist exposure energy. Since then the 2564 has been tested by Etec's standard Acceptance Test Procedure and by several supplementary HMM techniques to insure performance to all the Etec advertised specifications and certain additional HMM requirements that were more demanding and/or more thorough than the advertised specifications. The primary purpose of the HMM tests was to more closely duplicate mask usage. The performance aspects covered by the tests include registration accuracy and repeatability; linewidth accuracy, uniformity and linearity; stripe butting; stripe and scan linearity; edge quality; system cleanliness; minimum geometry resolution; minimum address size and plate loading accuracy and repeatability.
Organic-Inorganic Hydrophobic Nanocomposite Film with a Core-Shell Structure
Liu, Peng; Chen, Ying; Yu, Zhiwu
2016-01-01
A method to prepare novel organic-inorganic hydrophobic nanocomposite films was proposed by a site-specific polymerization process. The inorganic part, the core of the nanocomposite, is a ternary SiO2–Al2O3–TiO2 nanoparticles, which is grafted with methacryloxy propyl trimethoxyl silane (KH570), and wrapped by fluoride and siloxane polymers. The synthesized samples are characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectrscopy, X-ray diffractometry (XRD), contact angle meter (CA), and scanning electron microscope (SEM). The results indicate that the novel organic-inorganic hydrophobic nanocomposite with a core-shell structure was synthesized successfully. XRD analysis reveals the nanocomposite film has an amorphous structure, and FTIR analysis indicates the nanoparticles react with a silane coupling agent (methacryloxy propyl trimethoxyl silane KH570). Interestingly, the morphology of the nanoparticle film is influenced by the composition of the core. Further, comparing with the film synthesized by silica nanoparticles, the film formed from SiO2–Al2O3–TiO2 nanoparticles has higher hydrophobic performance, i.e., the contact angle is greater than 101.7°. In addition, the TEM analysis reveals that the crystal structure of the particles can be changed at high temperatures. PMID:28774141
NASA Astrophysics Data System (ADS)
Khaparde, Rohini A.; Acharya, Smita A.
2018-05-01
ZnS:Mn/ ZnS core/shell nanoparticles was prepared by two step synthesis method. In first step, oleic acid - coated Mn doped ZnS core nanoparticles were prepared which were charged through ligand exchange. Shell of ZnS NPs was finally deposited upon the surface of charged Mn doped ZnS core. Scanning electron microscopy (SEM) image exhibit morphological confirmation of ZnS:Mn/ZnS core/shell. As Nano ZnS are the most suitable candidates for photocatalyst that extensively involved in degradation and complete mineralization of various toxic organic pollutants owing to its high efficiency, strong oxidizing power, non-toxicity, high photochemical and biological stability, corrosive resistance and low cost. Photodegradation of malachite green is systematically investigated by adding different molar proportional of ZnS:Mn/ZnS core/shell in the dye. The rate of de-coloration of dye is detected by UV-VIS absorption spectroscopy. Efficient detoriation in the colour of dye is attributed to the core /shell morphology of the particles.
XAFS imaging of Tsukuba gabbroic rocks: area analysis of chemical composition and local structure.
Mizusawa, Mari; Sakurai, Kenji
2004-03-01
Gabbroic rocks were collected at Mount Tsukuba in Japan, and their XAFS images were studied using a projection-type X-ray fluorescence (XRF) microscope, which is a powerful new tool recently developed for extremely rapid imaging. The instrument employs a grazing-incidence arrangement in order that primary X-rays illuminate the whole sample surface, as well as parallel-beam optics and an extremely close geometry in order to detect XRF by a high-performance X-ray CCD system with 1024 x 1024 pixels. The XRF image indicated that black amphibole and white feldspar, both of which are typical mineral textures of the rock, contain iron. The origin has been suggested to be several small yellowish-brown minerals contained there. The XAFS imaging has been carried out by repeating the exposure of XRF images during the energy scan of the primary X-rays. It has been found that the structure is qualitatively close to that of olivine, and the main differences found in both areas can be explained as a difference in iron and magnesium concentration, i.e. the mixed ratio of forsterite (Mg(2)SiO(4)) and fayalite (Fe(2)SiO(4)). The feasibility of the present XAFS imaging method has been demonstrated for realistic inhomogeneous minerals.
NASA Astrophysics Data System (ADS)
Hagiwara, Osahiko; Watanabe, Manabu; Sato, Eiichi; Matsukiyo, Hiroshi; Osawa, Akihiro; Enomoto, Toshiyuki; Nagao, Jiro; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun
2011-06-01
An X-ray fluorescence computed tomography system (XRF-CT) is useful for determining the main atoms in objects. To detect iodine atoms without using a synchrotron, we developed an XRF-CT system utilizing a cadmium telluride (CdTe) detector and a cerium X-ray generator. CT is performed by repeated linear scans and rotations of an object. When cerium K-series characteristic X-rays are absorbed by iodine atoms in objects, iodine K fluorescence is produced from atoms and is detected by the CdTe detector. Next, event signals of X-ray photons are produced with the use of charge-sensitive and shaping amplifiers. Iodine Kα fluorescence is isolated using a multichannel analyzer, and the number of photons is counted using a counter card. In energy-dispersive XRF-CT, the tube voltage and tube current were 70 kV and 0.40 mA, respectively, and the X-ray intensity was 115.3 μGy/s at a distance of 1.0 m from the source. The demonstration of XRF-CT was carried out by the selection of photons in an energy range from 27.5 to 29.5 keV with a photon-energy resolution of 1.2 keV.
Fiber optic light collection system for scanning-tunneling-microscope-induced light emission.
Watkins, Neil J; Long, James P; Kafafi, Zakya H; Mäkinen, Antti J
2007-05-01
We report a compact light collection scheme suitable for retrofitting a scanning tunneling microscope (STM) for STM-induced light emission experiments. The approach uses a pair of optical fibers with large core diameters and high numerical apertures to maximize light collection efficiency and to moderate the mechanical precision required for alignment. Bench tests indicate that efficiency reduction is almost entirely due to reflective losses at the fiber ends, while losses due to fiber misalignment have virtually been eliminated. Photon-map imaging with nanometer features is demonstrated on a stepped Au(111) surface with signal rates exceeding 10(4) counts/s.
Lewis, Amelia K; Porter, Melanie A; Williams, Tracey A; Bzishvili, Samantha; North, Kathryn N; Payne, Jonathan M
2017-05-01
This study aimed to investigate face scan paths and face perception abilities in children with Neurofibromatosis Type 1 (NF1) and how these might relate to emotion recognition abilities in this population. The authors investigated facial emotion recognition, face scan paths, and face perception in 29 children with NF1 compared to 29 chronological age-matched typically developing controls. Correlations between facial emotion recognition, face scan paths, and face perception in children with NF1 were examined. Children with NF1 displayed significantly poorer recognition of fearful expressions compared to controls, as well as a nonsignificant trend toward poorer recognition of anger. Although there was no significant difference between groups in time spent viewing individual core facial features (eyes, nose, mouth, and nonfeature regions), children with NF1 spent significantly less time than controls viewing the face as a whole. Children with NF1 also displayed significantly poorer face perception abilities than typically developing controls. Facial emotion recognition deficits were not significantly associated with aberrant face scan paths or face perception abilities in the NF1 group. These results suggest that impairments in the perception, identification, and interpretation of information from faces are important aspects of the social-cognitive phenotype of NF1. (PsycINFO Database Record (c) 2017 APA, all rights reserved).
Eaton, Sandra S; Shi, Yilin; Woodcock, Lukas; Buchanan, Laura A; McPeak, Joseph; Quine, Richard W; Rinard, George A; Epel, Boris; Halpern, Howard J; Eaton, Gareth R
2017-07-01
In rapid-scan EPR the magnetic field or frequency is repeatedly scanned through the spectrum at rates that are much faster than in conventional continuous wave EPR. The signal is directly-detected with a mixer at the source frequency. Rapid-scan EPR is particularly advantageous when the scan rate through resonance is fast relative to electron spin relaxation rates. In such scans, there may be oscillations on the trailing edge of the spectrum. These oscillations can be removed by mathematical deconvolution to recover the slow-scan absorption spectrum. In cases of inhomogeneous broadening, the oscillations may interfere destructively to the extent that they are not visible. The deconvolution can be used even when it is not required, so spectra can be obtained in which some portions of the spectrum are in the rapid-scan regime and some are not. The technology developed for rapid-scan EPR can be applied generally so long as spectra are obtained in the linear response region. The detection of the full spectrum in each scan, the ability to use higher microwave power without saturation, and the noise filtering inherent in coherent averaging results in substantial improvement in signal-to-noise relative to conventional continuous wave spectroscopy, which is particularly advantageous for low-frequency EPR imaging. This overview describes the principles of rapid-scan EPR and the hardware used to generate the spectra. Examples are provided of its application to imaging of nitroxide radicals, diradicals, and spin-trapped radicals at a Larmor frequency of ca. 250MHz. Copyright © 2017 Elsevier Inc. All rights reserved.
... cervical spine; Computed tomography scan of cervical spine; CT scan of cervical spine; Neck CT scan ... table that slides into the center of the CT scanner. Once you are inside the scanner, the ...
NASA Astrophysics Data System (ADS)
Kim, Su Yeon; Jeong, Jong Seok; Mkhoyan, K. Andre; Jang, Ho Seong
2016-05-01
Highly efficient downconversion (DC) green-emitting LiYF4:Ce,Tb nanophosphors have been synthesized for bright dual-mode upconversion (UC) and DC green-emitting core/double-shell (C/D-S) nanophosphors--Li(Gd,Y)F4:Yb(18%),Er(2%)/LiYF4:Ce(15%),Tb(15%)/LiYF4--and the C/D-S structure has been proved by extensive scanning transmission electron microscopy (STEM) analysis. Colloidal LiYF4:Ce,Tb nanophosphors with a tetragonal bipyramidal shape are synthesized for the first time and they show intense DC green light via energy transfer from Ce3+ to Tb3+ under illumination with ultraviolet (UV) light. The LiYF4:Ce,Tb nanophosphors show 65 times higher photoluminescence intensity than LiYF4:Tb nanophosphors under illumination with UV light and the LiYF4:Ce,Tb is adapted into a luminescent shell of the tetragonal bipyramidal C/D-S nanophosphors. The formation of the DC shell on the core significantly enhances UC luminescence from the UC core under irradiation of near infrared light and concurrently generates DC luminescence from the core/shell nanophosphors under UV light. Coating with an inert inorganic shell further enhances the UC-DC dual-mode luminescence by suppressing the surface quenching effect. The C/D-S nanophosphors show 3.8% UC quantum efficiency (QE) at 239 W cm-2 and 73.0 +/- 0.1% DC QE. The designed C/D-S architecture in tetragonal bipyramidal nanophosphors is rigorously verified by an energy dispersive X-ray spectroscopy (EDX) analysis, with the assistance of line profile simulation, using an aberration-corrected scanning transmission electron microscope equipped with a high-efficiency EDX. The feasibility of these C/D-S nanophosphors for transparent display devices is also considered.Highly efficient downconversion (DC) green-emitting LiYF4:Ce,Tb nanophosphors have been synthesized for bright dual-mode upconversion (UC) and DC green-emitting core/double-shell (C/D-S) nanophosphors--Li(Gd,Y)F4:Yb(18%),Er(2%)/LiYF4:Ce(15%),Tb(15%)/LiYF4--and the C/D-S structure
Translucency of zirconia-based pressable ceramics with different core and veneer thicknesses.
Jeong, Il-Do; Bae, So-Yeon; Kim, Dong-Yeon; Kim, Ji-Hwan; Kim, Woong-Chul
2016-06-01
Little information is available on the translucency of zirconia-based pressable ceramic restorations with a pressed ceramic veneer and zirconia core in various thickness combinations. The purpose of this in vitro study was to assess the translucency of 3 types of zirconia-based pressable ceramics for different core-veneer thickness combinations. A bilayered ceramic specimen was prepared with a pressable ceramic (IPS e.max Zirpress, Initial IQ, Rosetta UltraPress) veneer over a zirconia core (Zenostar Zr). Three groups of specimens (n=7) were formed with the following core+veneer thicknesses: 1 +0.5 mm, 0.7 +0.8 mm, and 0.5 +1 mm. To obtain consistent thickness and high translucency, all specimens were subjected to surface grinding with a grinding machine. To eliminate the effect of differences in roughness on the translucency, the surface roughness of the ground specimens was measured with a scanning profiler, and the consistency of these measured values was verified through statistical analysis. The luminous transmittance of the specimens was measured with a spectrophotometer. The effects of the pressable ceramic type and core-veneer thickness combination on transmittance were assessed using a 2-way ANOVA (α=.05). The consistency of the surface roughness among the tested specimens was confirmed using a 1-way ANOVA and the Tukey HSD post hoc test (P<.05). The luminous transmittance exhibited a statistically significant dependence on both the type of pressable ceramic and the core-veneer thickness combination (P<.05). The type of pressable ceramic and core-veneer thickness combination affected the translucency of the restoration. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.
Synthesis of SiCN@TiO2 core-shell ceramic microspheres via PDCs method
NASA Astrophysics Data System (ADS)
Liu, Hongli; Wei, Ning; Li, Jing; Zhang, Haiyuan; Chu, Peng
2018-02-01
A facile and effective polymer-derived ceramics (PDCs) emulsification-crosslinking-pyrolysis method was developed to fabricate SiCN@TiO2 core-shell ceramic microspheres with polyvinylsilazane (PVSZ) and tetrabutyl titanate (TBT) as precursors. The TBT: PVSZ mass ratios, emulsifier concentrations and the pyrolysis temperature were examined as control parameters to tune the size and morphology of microspheres. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) confirmed the synthesized SiCN@TiO2 microspheres to be comprised of SiCN core coated with TiO2 crystals, with an average size of 0.88 μm when pyrolyzed at 1400 °C. The analysis of Fourier transform infrared spectroscopy (FT-IR), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) ensured that SiCN@TiO2 core-shell ceramic microspheres composed of rutile TiO2, β-SiC and Si3N4 crystalline phases, The thermal properties were characterized by thermogravimetric analysis (TGA). The obtained SiCN@TiO2 core-shell ceramic microspheres were the promising candidate of the infrared opacifier in silica aerogels and this technique can be extended to other preceramic polymers.
Xiao, J; Foray, G; Masenelli-Varlot, K
2018-02-01
Environmental scanning electron microscopy (ESEM) allows the observation of liquids under specific conditions of pressure and temperature. Moreover, when working in the transmission mode, that is in scanning transmission electron microscopy (STEM), nano-objects can be analysed inside a liquid. The contrast in the images is mass-thickness dependent as in STEM-in-TEM (transmission electron microscopy) using closed cells. However, in STEM-in-ESEM, as the liquid-vapour equilibrium is kept dynamically, the thickness of the water droplet remains unknown. In this paper, the contrasts measured in the experimental images are compared with calculations using Monte-Carlo simulations in order to estimate the thickness of water. Two examples are given. On gold nanoparticles, the thickness of a thick film can be estimated thanks to a contrast inversion. On core-shell latex particles, the grey level of the shell compared with those of the core and of the water film gives a relatively precise measurement of the water film thickness. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.
Wang, Kangkang; Lin, Wenzhi; Chinchore, Abhijit V; Liu, Yinghao; Smith, Arthur R
2011-05-01
A room-temperature ultra-high-vacuum scanning tunneling microscope for in situ scanning freshly grown epitaxial films has been developed. The core unit of the microscope, which consists of critical components including scanner and approach motors, is modular designed. This enables easy adaptation of the same microscope units to new growth systems with different sample-transfer geometries. Furthermore the core unit is designed to be fully compatible with cryogenic temperatures and high magnetic field operations. A double-stage spring suspension system with eddy current damping has been implemented to achieve ≤5 pm z stability in a noisy environment and in the presence of an interconnected growth chamber. Both tips and samples can be quickly exchanged in situ; also a tunable external magnetic field can be introduced using a transferable permanent magnet shuttle. This allows spin-polarized tunneling with magnetically coated tips. The performance of this microscope is demonstrated by atomic-resolution imaging of surface reconstructions on wide band-gap GaN surfaces and spin-resolved experiments on antiferromagnetic Mn(3)N(2)(010) surfaces.
The core domain as the force sensor of the yeast mechanosensitive TRP channel.
Su, Zhenwei; Anishkin, Andriy; Kung, Ching; Saimi, Yoshiro
2011-12-01
Stretch-activated conductances are commonly encountered in careful electric recordings. Those of known proteins (TRP, MscL, MscS, K(2p), Kv, etc.) all share a core, which houses the ion pathway and the gate, but no recognizable force-sensing domain. Like animal TRPs, the yeast TRPY1 is polymodal, activated by stretch force, Ca(2+), etc. To test whether its S5-S6 core senses the stretch force, we tried to uncouple it from the peripheral domains by strategic peptide insertions to block the covalent core-periphery interactions. Insertion of long unstructured peptides should distort, if not disrupt, protein structures that transmit force. Such insertions between S6 and the C-terminal tail largely removed Ca(2+) activation, showing their effectiveness. However, such insertions as well as those between S5 and the N-terminal region, which includes S1-S4, did not significantly alter mechanosensitivity. Even insertions at both locations flanking the S5-S6 core did not much alter mechanosensitivity. Tryptophan scanning mutations in S5 were also constructed to perturb possible noncovalent core-periphery contacts. The testable tryptophan mutations also have little or no effects on mechanosensitivity. Boltzmann fits of the wild-type force-response curves agree with a structural homology model for a stretch-induced core expansion of ~2 nm(2) upon opening. We hypothesize that membrane tension pulls on S5-S6, expanding the core and opening the TRPY1 gate. The core being the major force sensor offers the simplest, though not the only, explanation of why so many channels of disparate designs are mechanically sensitive. Compared with the bacterial MscL, TRPY1 is much less sensitive to force, befitting a polymodal channel that relies on multiple stimuli.
Infrared zone-scanning system.
Belousov, Aleksandr; Popov, Gennady
2006-03-20
Challenges encountered in designing an infrared viewing optical system that uses a small linear detector array based on a zone-scanning approach are discussed. Scanning is performed by a rotating refractive polygon prism with tilted facets, which, along with high-speed line scanning, makes the scanning gear as simple as possible. A method of calculation of a practical optical system to compensate for aberrations during prism rotation is described.
Update on the magnetic resonance imaging core of the Alzheimer's disease neuroimaging initiative.
Jack, Clifford R; Bernstein, Matt A; Borowski, Bret J; Gunter, Jeffrey L; Fox, Nick C; Thompson, Paul M; Schuff, Norbert; Krueger, Gunnar; Killiany, Ronald J; Decarli, Charles S; Dale, Anders M; Carmichael, Owen W; Tosun, Duygu; Weiner, Michael W
2010-05-01
Functions of the Alzheimer's Disease Neuroimaging Initiative (ADNI) magnetic resonance imaging (MRI) core fall into three categories: (1) those of the central MRI core laboratory at Mayo Clinic, Rochester, Minnesota, needed to generate high quality MRI data in all subjects at each time point; (2) those of the funded ADNI MRI core imaging analysis groups responsible for analyzing the MRI data; and (3) the joint function of the entire MRI core in designing and problem solving MR image acquisition, pre-processing, and analyses methods. The primary objective of ADNI was and continues to be improving methods for clinical trials in Alzheimer's disease. Our approach to the present ("ADNI-GO") and future ("ADNI-2," if funded) MRI protocol will be to maintain MRI methodological consistency in the previously enrolled "ADNI-1" subjects who are followed up longitudinally in ADNI-GO and ADNI-2. We will modernize and expand the MRI protocol for all newly enrolled ADNI-GO and ADNI-2 subjects. All newly enrolled subjects will be scanned at 3T with a core set of three sequence types: 3D T1-weighted volume, FLAIR, and a long TE gradient echo volumetric acquisition for micro hemorrhage detection. In addition to this core ADNI-GO and ADNI-2 protocol, we will perform vendor-specific pilot sub-studies of arterial spin-labeling perfusion, resting state functional connectivity, and diffusion tensor imaging. One of these sequences will be added to the core protocol on systems from each MRI vendor. These experimental sub-studies are designed to demonstrate the feasibility of acquiring useful data in a multicenter (but single vendor) setting for these three emerging MRI applications. Copyright 2010 The Alzheimer
MutScan: fast detection and visualization of target mutations by scanning FASTQ data.
Chen, Shifu; Huang, Tanxiao; Wen, Tiexiang; Li, Hong; Xu, Mingyan; Gu, Jia
2018-01-22
Some types of clinical genetic tests, such as cancer testing using circulating tumor DNA (ctDNA), require sensitive detection of known target mutations. However, conventional next-generation sequencing (NGS) data analysis pipelines typically involve different steps of filtering, which may cause miss-detection of key mutations with low frequencies. Variant validation is also indicated for key mutations detected by bioinformatics pipelines. Typically, this process can be executed using alignment visualization tools such as IGV or GenomeBrowse. However, these tools are too heavy and therefore unsuitable for validating mutations in ultra-deep sequencing data. We developed MutScan to address problems of sensitive detection and efficient validation for target mutations. MutScan involves highly optimized string-searching algorithms, which can scan input FASTQ files to grab all reads that support target mutations. The collected supporting reads for each target mutation will be piled up and visualized using web technologies such as HTML and JavaScript. Algorithms such as rolling hash and bloom filter are applied to accelerate scanning and make MutScan applicable to detect or visualize target mutations in a very fast way. MutScan is a tool for the detection and visualization of target mutations by only scanning FASTQ raw data directly. Compared to conventional pipelines, this offers a very high performance, executing about 20 times faster, and offering maximal sensitivity since it can grab mutations with even one single supporting read. MutScan visualizes detected mutations by generating interactive pile-ups using web technologies. These can serve to validate target mutations, thus avoiding false positives. Furthermore, MutScan can visualize all mutation records in a VCF file to HTML pages for cloud-friendly VCF validation. MutScan is an open source tool available at GitHub: https://github.com/OpenGene/MutScan.
NASA Astrophysics Data System (ADS)
Kent, T.
2011-12-01
The goal of this study is to constrain the most recent thermal alteration of two drill cores (HSB2/HSB4) from the Island of Akutan in the Aleutian Islands of Alaska. These cores are characterized by identifying mineralogy using x-ray diffraction spectra, energy dispersive spectroscopy with a scanning electron microscope and optical mineralogy. This is then compared with the coincident thermal data gathered on site in order to help constrain the most recent thermal activity of this dynamic resource. Using multiple temperature diagnostic minerals and their paragenesis, a relative thermal history is produced of expansive propylitic alteration. When combined with the wireline temperature gradients of the cores a model of downward migration emerges. Shallow occurrences of high temperature minerals that lie above the boiling point to depth curve indicate higher hydrostatic pressures in the past which can be attributed to a combination of glacial effects, including a significant amount of glacial erosion that is recognized due to a lack of significant clay cap to the geothermal resource.
Lake deposits record evidence of large post-1505 AD earthquakes in western Nepal
NASA Astrophysics Data System (ADS)
Ghazoui, Z.; Bertrand, S.; Vanneste, K.; Yokoyama, Y.; Van Der Beek, P.; Nomade, J.; Gajurel, A.
2016-12-01
According to historical records, the last large earthquake that ruptured the Main Frontal Thrust (MFT) in western Nepal occurred in 1505 AD. Since then, no evidence of other large earthquakes has been found in historical records or geological archives. In view of the catastrophic consequences to millions of inhabitants of Nepal and northern India, intense efforts currently focus on improving our understanding of past earthquake activity and complement the historical data on Himalayan earthquakes. Here we report a new record, based on earthquake-triggered turbidites in lakes. We use lake sediment records from Lake Rara, western Nepal, to reconstruct the occurrence of seismic events. The sediment cores were studied using a multi-proxy approach combining radiocarbon and 210Pb chronologies, physical properties (X-ray computerized axial tomography scan, Geotek multi-sensor core logger), high-resolution grain size, inorganic geochemistry (major elements by ITRAX XRF core scanning) and bulk organic geochemistry (C, N concentrations and stable isotopes). We identified several sequences of dense and layered fine sand mainly composed of mica, which we interpret as earthquake-triggered turbidites. Our results suggest the presence of a synchronous event between the two lake sites correlated with the well-known 1505 AD earthquake. In addition, our sediment records reveal five earthquake-triggered turbidites younger than the 1505 AD event. By comparison with historical archives, we relate one of those to the 1833 AD MFT rupture. The others may reflect successive ruptures of the Western Nepal Fault System. Our study sheds light on events that have not been recorded in historical chronicles. Those five MMI>7 earthquakes permit addressing the problem of missing slip on the MFT in western Nepal and reevaluating the risk of a large earthquake affecting western Nepal and North India.
... PET - chest; PET - lung; PET - tumor imaging; PET/CT - lung; Solitary pulmonary nodule - PET ... minutes. PET scans are performed along with a CT scan. This is because the combined information from ...
Lidar arc scan uncertainty reduction through scanning geometry optimization
NASA Astrophysics Data System (ADS)
Wang, Hui; Barthelmie, Rebecca J.; Pryor, Sara C.; Brown, Gareth.
2016-04-01
Doppler lidars are frequently operated in a mode referred to as arc scans, wherein the lidar beam scans across a sector with a fixed elevation angle and the resulting measurements are used to derive an estimate of the n minute horizontal mean wind velocity (speed and direction). Previous studies have shown that the uncertainty in the measured wind speed originates from turbulent wind fluctuations and depends on the scan geometry (the arc span and the arc orientation). This paper is designed to provide guidance on optimal scan geometries for two key applications in the wind energy industry: wind turbine power performance analysis and annual energy production prediction. We present a quantitative analysis of the retrieved wind speed uncertainty derived using a theoretical model with the assumption of isotropic and frozen turbulence, and observations from three sites that are onshore with flat terrain, onshore with complex terrain and offshore, respectively. The results from both the theoretical model and observations show that the uncertainty is scaled with the turbulence intensity such that the relative standard error on the 10 min mean wind speed is about 30 % of the turbulence intensity. The uncertainty in both retrieved wind speeds and derived wind energy production estimates can be reduced by aligning lidar beams with the dominant wind direction, increasing the arc span and lowering the number of beams per arc scan. Large arc spans should be used at sites with high turbulence intensity and/or large wind direction variation.
Core formation and core composition from coupled geochemical and geophysical constraints
Badro, James; Brodholt, John P.; Piet, Helene; ...
2015-09-21
The formation of Earth’s core left behind geophysical and geochemical signatures in both the core and mantle that remain to this day. Seismology requires that the core be lighter than pure iron and therefore must contain light elements, and the geochemistry of mantle-derived rocks reveals extensive siderophile element depletion and fractionation. Both features are inherited from metal–silicate differentiation in primitive Earth and depend upon the nature of physiochemical conditions that prevailed during core formation. To date, core formation models have only attempted to address the evolution of core and mantle compositional signatures separately, rather than seeking a joint solution. Heremore » we combine experimental petrology, geochemistry, mineral physics and seismology to constrain a range of core formation conditions that satisfy both constraints. We find that core formation occurred in a hot (liquidus) yet moderately deep magma ocean not exceeding 1,800 km depth, under redox conditions more oxidized than present-day Earth. This new scenario, at odds with the current belief that core formation occurred under reducing conditions, proposes that Earth’s magma ocean started oxidized and has become reduced through time, by oxygen incorporation into the core. As a result, this core formation model produces a core that contains 2.7–5% oxygen along with 2–3.6% silicon, with densities and velocities in accord with radial seismic models, and leaves behind a silicate mantle that matches the observed mantle abundances of nickel, cobalt, chromium, and vanadium.« less
Core formation and core composition from coupled geochemical and geophysical constraints
DOE Office of Scientific and Technical Information (OSTI.GOV)
Badro, James; Brodholt, John P.; Piet, Helene
The formation of Earth’s core left behind geophysical and geochemical signatures in both the core and mantle that remain to this day. Seismology requires that the core be lighter than pure iron and therefore must contain light elements, and the geochemistry of mantle-derived rocks reveals extensive siderophile element depletion and fractionation. Both features are inherited from metal–silicate differentiation in primitive Earth and depend upon the nature of physiochemical conditions that prevailed during core formation. To date, core formation models have only attempted to address the evolution of core and mantle compositional signatures separately, rather than seeking a joint solution. Heremore » we combine experimental petrology, geochemistry, mineral physics and seismology to constrain a range of core formation conditions that satisfy both constraints. We find that core formation occurred in a hot (liquidus) yet moderately deep magma ocean not exceeding 1,800 km depth, under redox conditions more oxidized than present-day Earth. This new scenario, at odds with the current belief that core formation occurred under reducing conditions, proposes that Earth’s magma ocean started oxidized and has become reduced through time, by oxygen incorporation into the core. As a result, this core formation model produces a core that contains 2.7–5% oxygen along with 2–3.6% silicon, with densities and velocities in accord with radial seismic models, and leaves behind a silicate mantle that matches the observed mantle abundances of nickel, cobalt, chromium, and vanadium.« less
NASA Astrophysics Data System (ADS)
Gawałkiewicz, Rafał
2015-12-01
There are many surveying methods to measure the inclination of a chimney with the use of classical protractor instruments (Theo 010A/B, T2 Wild), electronic theodolites (TC2002 Wild-Leica), electronic total stations, including mirrorless ones, allowing to define indirectly the course of the construction's axis on the selected observation levels. The methods are the following: indentations, direct projection, double-edged method, polar method with the option of mirrorless measurement. At the moment a very practical and quick measurement technology, significantly eliminating the influence of human errors on the observation results, is laser scanning. The article presents the results of the scanning of 120-metres high reinforced concrete industrial chimney of the Cement Plant "Ożarów", with the application of modern scanning total station VX Spatial Station by Trimble, as an alternative to the methods applied so far. The advantage of scanning is the possibility to obtain a point cloud, which, apart from the information on the course of the chimney axis in the space, provides detail information on the real shape and deformations of the coating of the object's core.
Thakur, Neha; Sargur Ranganath, Anupama; Sopiha, Kostiantyn; Baji, Avinash
2017-08-30
In this study, we used core-shell electrospinning to fabricate cellulose acetate-poly(N-isopropylacrylamide) (CA-PNIPAM) fibrous membranes and demonstrated the ability of these fibers to capture water from a high humid atmosphere and release it when thermally stimulated. The wettability of the fibers was controlled by using thermoresponsive PNIPAM as the shell layer. Scanning electron and fluorescence microscopes are used to investigate the microstructure of the fibers and confirm the presence of the core and shell phases within the fibers. The moisture capturing and releasing ability of these core-shell CA-PNIPAM fibers was compared with those of the neat CA and neat PNIPAM fibers at room temperature as well as at an elevated temperature. At room temperature, the CA-PNIPAM core-shell fibers are shown to have the maximum moisture uptake capacity among the three samples. The external temperature variations which trigger the moisture response behavior of these CA-PNIPAM fibers fall within the range of typical day and night cycles of deserts, demonstrating the potential use of these fibers for water harvesting applications.
... page: //medlineplus.gov/ency/article/003835.htm RBC nuclear scan To use the sharing features on this page, please enable JavaScript. An RBC nuclear scan uses small amounts of radioactive material to ...
... Computed tomography scan - heart; Calcium scoring; Multi-detector CT scan - heart; Electron beam computed tomography - heart; Agatston ... table that slides into the center of the CT scanner. You will lie on your back with ...
Through-focus scanning optical microscopy (TSOM) with adaptive optics
NASA Astrophysics Data System (ADS)
Lee, Jun Ho; Park, Gyunam; Jeong, Junhee; Park, Chris
2018-03-01
Through-focus optical microscopy (TSOM) with nanometer-scale lateral and vertical sensitivity levels matching those of scanning electron microscopy has been demonstrated to be useful both for 3D inspections and metrology assessments. In 2014, funded by two private companies (Nextin/Samsung Electronics) and the Korea Evaluation Institute of Industrial Technology (KEIT), a research team from four universities in South Korea set out to investigate core technologies for developing in-line TSOM inspection and metrology tools, with the respective teams focusing on optics implementation, defect inspection, computer simulation and high-speed metrology matching. We initially confirmed the reported validity of the TSOM operation through a computer simulation, after which we implemented the TSOM operation by throughfocus scanning of existing UV (355nm) and IR (800nm) inspection tools. These tools have an identical sampling distance of 150 nm but have different resolving distances (310 and 810 nm, respectively). We initially experienced some improvement in the defect inspection sensitivity level over TSV (through-silicon via) samples with 6.6 μm diameters. However, during the experiment, we noted sensitivity and instability issues when attempting to acquire TSOM images. As TSOM 3D information is indirectly extracted by differentiating a target TSOM image from reference TSOM images, any instability or mismatch in imaging conditions can result in measurement errors. As a remedy to such a situation, we proposed the application of adaptive optics to the TSOM operation and developed a closed-loop system with a tip/tilt mirror and a Shack-Hartmann sensor on an optical bench. We were able to keep the plane position within in RMS 0.4 pixel by actively compensating for any position instability which arose during the TSOM scanning process along the optical axis. Currently, we are also developing another TSOM tool with a deformable mirror instead of a tip/tilt mirror, in which case we
DepositScan, a Scanning Program to Measure Spray Deposition Distributions
USDA-ARS?s Scientific Manuscript database
DepositScan, a scanning program was developed to quickly measure spray deposit distributions on water sensitive papers or Kromekote cards which are widely used for determinations of pesticide spray deposition quality on target areas. The program is installed in a portable computer and works with a ...
NASA Astrophysics Data System (ADS)
West, Patricia; Baker, Lionel R.
1989-03-01
This paper is a review of the applications of laser scanning in inspection. The reasons for the choice of a laser in flying spot scanning and the optical properties of a laser beam which are of value in a scanning instrument will be given. The many methods of scanning laser beams in both one and two dimensions will be described. The use of one dimensional laser scanners for automatic surface inspection for transmitting and reflective products will be covered in detail, with particular emphasis on light collection techniques. On-line inspection applications which will be mentioned include: photographic film web, metal strip products, paper web, glass sheet, car body paint surfaces and internal cylinder bores. Two dimensional laser scanning is employed in applications where increased resolution, increased depth of focus, and better contrast are required compared with conventional vidicon TV or solid state array cameras. Such examples as special microscope laser scanning systems and a TV compatible system for use in restricted areas of a nuclear reactor will be described. The technical and economic benefits and limitations of laser scanning video systems will be compared with conventional TV and CCD array devices.
NASA Astrophysics Data System (ADS)
Kiaalhosseini, Saeed
. HTA of frozen core was employed at the former refinery and FEW. Porosity and fluid saturations (i.e., aqueous, non-aqueous liquid, and gas) from the former refinery indicate that given in situ freezing, the results are not biased by drainage of pore fluids from the core during sample collection. At FEW, a comparison between the results of HTA of the frozen core collected in 2014 and the results of site characterization using unfrozen core, (second-generation (2G) methods) at the same locations (performed in 2010) indicate consistently higher contaminant concentrations using C 3. Many factors contribute to the higher quantification of contaminant concentrations using C3. The most significant factor is the preservation of the sediment attributes, in particular, pore fluids and volatile organic compounds (VOCs) in comparison to the unfrozen conventional sediment core. The NMR study was performed on laboratory-fabricated sediment core to resolve NAPL distribution within the porous media qualitatively and quantitatively. The fabricated core consisted of Colorado silica sand saturated with deionized water and trichloroethylene (TCE). The cores were scanned with a BRUKER small-animal scanner (2.3 Tesla, 100 MHz) at 20 °C and while the core was frozen at -25 °C. The acquired images indicated that freezing the water within the core suppressed the NMR signals of water-bound hydrogen. The hydrogen associated with TCE was still detectable since the TCE was in its liquid state (melting point of TCE is -73 °C). Therefore, qualitative detection of TCE within the sediment core was performed via the NMR scanning by freezing the water. A one-dimensional NMR scanning method was used for quantification of TCE mass distribution within the frozen core. However, the results indicated inconsistency in estimating the total TCE mass within the porous media. Downhole NMR logging was performed at the former refinery in the western U.S. to detect NAPL and to discriminate NAPL from water in the