The rhenium isotope composition of Atlantic Ocean seawater

The concentrations and isotopic compositions of rhenium are presented from seawater samples obtained from the primary station for the Bermuda Atlantic Time Series Study in the North Atlantic Ocean and from the 40oS UK GEOTRACES expedition in the South Atlantic Ocean. Salinity-normalized Re concentrations in both locations range between ∼6.8–7.7 ppt between 50–5000 m depth, consistent with previously published concentration data from the North Atlantic and North Pacific Oceans. Rhenium isotope values (expressed as δ187/185Re relative to NIST 3143) exhibit minimal variation around an average value of −0.17 ± 0.12‰ (n = 12, 2 S.D.), irrespective of water depth or water mass. These results confirm that the isotopic composition of perrhenate (ReO4−) in seawater is uniform. The new data establish a baseline for evaluating the isotopic mass balance of Re, and for future assessments of whether this global cycle can be disturbed by changes in seafloor redox and/or global weathering rates

Dye-Sensitized Solar Cells Using Mesocarbon Microbead-Based Counter Electrodes

The dye-sensitized solar cells (DSCs) equipped with mesocarbon microbead (MCMB)-based counter electrodes were explored to examine their cell performance. Three types of nanosized additives including platinum, carbon nanotubes (CNTs), and carbon black (CB) are well dispersed and coated over microscaled MCMB powders. In the design of the counter electrodes, the MCMB graphite offers an excellent medium that allows charge transfer from the ITO substrate to the dye molecule. The active materials such as Pt, CNT, and nanosize CB act as an active site provider for the redox reaction. Among these counter electrodes, the DSCs fabricated with CB electrode exhibit the highest power conversion efficiency. This improved efficiency can be attributed to the fact that the CB nanoparticles not only offer a large number of catalytic sites but also low charge transfer resistance, facilitating a rapid reaction kinetics. Such design of carbon counter electrode has been confirmed to be a promising candidate for replacing Pt electrodes

Barium isotopes in mid-ocean ridge hydrothermal vent fluids : a source of isotopically heavy Ba to the ocean

Funding: These field and related experimental studies were supported through US NSF grants: 0549547, 0751771, 0813861, 0961188 and 1736679 (WES).Mid-ocean ridge (MOR) hydrothermal vent fluids are enriched with dissolved barium, but due to barite (BaSO4) precipitation during mixing between Ba-bearing vent fluids and SO4-bearing seawater, the magnitude of hydrothermal Ba input to the ocean remains uncertain. Deep-ocean Ba isotopes show evidence for non-conservative behavior, which might be explained by input of isotopically heavy hydrothermal Ba. In this study we present the first Ba isotope data in mid-ocean ridge hydrothermal vent fluids and particles from systems on the Mid-Atlantic Ridge (Rainbow 36°N and TAG 26°N), the East Pacific Rise (EPR9–10°N and 13°N) and the Juan de Fuca Ridge (MEF and ASHES). The vent fluids display a wide range of dissolved Ba concentrations from 0.43 to 97.9 μmol/kg and δ138/134Ba values from −0.26 to +0.91‰, but are modified relative to initial composition due to precipitation of barite. Calculated endmember vent fluid δ138/134Ba values, prior to barite precipitation, are between −0.17 and +0.09‰, consistent with the values observed in oceanic basalts and pelagic sediments. Water-rock interaction at depth in the oceanic crust appears to occur without Ba isotope fractionation. During subsequent venting and mixing with seawater, barite precipitation preferentially removes isotopically light Ba from vent fluids with a fractionation factor of Δ138/134Bahyd-barite-fluid = −0.35 ± 0.10‰ (2SE, n = 2). Based on knowledge of barite saturation and isotope fractionation during precipitation, the effective hydrothermal Ba component that mixes with seawater after barite precipitation has completed can be calculated: δ138/134Bahyd = +1.7 ± 0.7‰ (2SD). This value is isotopically heavier than deep ocean waters and may explain the observed non-conservative of Ba isotopes in deep waters. These new constraints on hydrothermal Ba compositions enable the hydrothermal input of Ba to Atlantic deep waters to be assessed at ≈3–9% of the observed Ba. Barium isotopes might be used as a tracer to reconstruct the history of hydrothermal Ba inputs and seawater SO4 concentrations in the past.PostprintPeer reviewe

PGT-Net: Progressive Guided Multi-task Neural Network for Small-area Wet Fingerprint Denoising and Recognition

Fingerprint recognition on mobile devices is an important method for identity verification. However, real fingerprints usually contain sweat and moisture which leads to poor recognition performance. In addition, for rolling out slimmer and thinner phones, technology companies reduce the size of recognition sensors by embedding them with the power button. Therefore, the limited size of fingerprint data also increases the difficulty of recognition. Denoising the small-area wet fingerprint images to clean ones becomes crucial to improve recognition performance. In this paper, we propose an end-to-end trainable progressive guided multi-task neural network (PGT-Net). The PGT-Net includes a shared stage and specific multi-task stages, enabling the network to train binary and non-binary fingerprints sequentially. The binary information is regarded as guidance for output enhancement which is enriched with the ridge and valley details. Moreover, a novel residual scaling mechanism is introduced to stabilize the training process. Experiment results on the FW9395 and FT-lightnoised dataset provided by FocalTech shows that PGT-Net has promising performance on the wet-fingerprint denoising and significantly improves the fingerprint recognition rate (FRR). On the FT-lightnoised dataset, the FRR of fingerprint recognition can be declined from 17.75% to 4.47%. On the FW9395 dataset, the FRR of fingerprint recognition can be declined from 9.45% to 1.09%

Fabrication of Inorganic Coatings Incorporated with Functionalized Graphene Oxide Nanosheets for Improving Fire Retardancy of Wooden Substrates

Flame-retardant chemicals are frequently used within consumer products and can even be employed as a treatment on the surface of different types of materials (e.g., wood, steel, and textiles) to prevent fire or limit the rapid spread of flames. Functionalized graphene oxide (FGO) nanosheets are a promising construction coating nanomaterial that can be blended with sodium metasilicate and gypsum to reduce the flammability of construction buildings. In this work, we designed and fabricated novel and halogen-free FGO sheets using the modified Hummers method; and subsequently functionalized them by pentaerythritol through a chemical impregnation process before dispersing them within the construction coating. Scanning electron microscopic images confirm that the FGO-filled coating was uniformly dispersed on the surface of wooden substrates. We identified that the FGO content is a critical factor affecting the fire retardancy. Thermogravimetric analysis of the FGO coating revealed that higher char residue can be obtained at 700 °C. Based on the differential scanning calorimetry, the exothermic peak contained a temperature delay in the presence of FGO sheets, primarily due to the formation of a thermal barrier. Such a significant improvement in the flame retardancy confirms that the FGO nanosheets are superior nanomaterials to be employed as a flame-retardant construction coating nanomaterial for improving thermal management within buildings

The controllable of alignment state of polyimide-free liquid crystal displays by adjusting parameter of process technology

In this report, we systematically investigated the influence of the concentration of additive, the routes and temperature of possess, liquid crystal drop filling pattern and diffusion distance on the polyimide-free liquid crystal display. We explores a series of LC cells containing SVA additive with different concentration, including mass ratio of 1%, 2 %, 3%. Adjusting process temperature and routes, we raised temperature at 120 °C before UV light irradiation, then compared alignment force variation at different concentration of additive. We also investigate the effect of additive diffusion distance on polyimide-free liquid crystal display by changed LC drop filling pattern. The obtained LC cells were characterized and tested using microscope, liquid crystal reliability measuring nstrument. In this report, we will describe the alignment state, voltage holding property(VHR), and electro-optical property of SVA-LC cells. We presume the inner relationship among alignment force, additive concentration and diffusion distance. The self alignment force will decrease with diffusion distance increasing, increase with concentration increasing

18F-FDG PET/CT-based gross tumor volume definition for radiotherapy in head and neck Cancer: a correlation study between suitable uptake value threshold and tumor parameters

<p>Abstract</p> <p>Background</p> <p>To define a suitable threshold setting for gross tumor volume (GTV) when using ¹⁸Fluoro-deoxyglucose positron emission tomography and computed tomogram (PET/CT) for radiotherapy planning in head and neck cancer (HNC).</p> <p>Methods</p> <p>Fifteen HNC patients prospectively received PET/CT simulation for their radiation treatment planning. Biological target volume (BTV) was derived from PET/CT-based GTV of the primary tumor. The BTVs were defined as the isodensity volumes when adjusting different percentage of the maximal standardized uptake value (SUVmax), excluding any artifact from surrounding normal tissues. CT-based primary GTV (C-pGTV) that had been previously defined by radiation oncologists was compared with the BTV. Suitable threshold level (sTL) could be determined when BTV value and its morphology using a certain threshold level was observed to be the best fitness of the C-pGTV. Suitable standardized uptake value (sSUV) was calculated as the sTL multiplied by the SUVmax.</p> <p>Results</p> <p>Our result demonstrated no single sTL or sSUV method could achieve an optimized volumetric match with the C-pGTV. The sTL was 13% to 27% (mean, 19%), whereas the sSUV was 1.64 to 3.98 (mean, 2.46). The sTL was inversely correlated with the SUVmax [sTL = -0.1004 Ln (SUVmax) + 0.4464; R²= 0.81]. The sSUV showed a linear correlation with the SUVmax (sSUV = 0.0842 SUVmax + 1.248; R²= 0.89). The sTL was not associated with the value of C-pGTVs.</p> <p>Conclusion</p> <p>In PET/CT-based BTV for HNC, a suitable threshold or SUV level can be established by correlating with SUVmax rather than using a fixed threshold.</p

226Ra determination via the rate of 222Rn ingrowth with the Radium Delayed Coincidence Counter (RaDeCC)

ISI Document Delivery No.: 278HU Times Cited: 0 Cited Reference Count: 23 Cited References: Annett AL, 2013, ANTARCT SCI, V25, P445, DOI 10.1017/S0954102012000892 Bourquin M, 2011, MAR CHEM, V126, P132, DOI 10.1016/j.marchem.2011.05.001 Burnett WC, 2006, SCI TOTAL ENVIRON, V367, P498, DOI 10.1016/j.scitotenv.2006.05.009 BUTTS J, 1988, MAR CHEM, V25, P349, DOI 10.1016/0304-4203(88)90115-6 Charette MA, 2012, LIMNOL OCEANOGR-METH, V10, P451, DOI 10.4319/lom.2012.10.451 Charette MA, 2001, LIMNOL OCEANOGR, V46, P465 Foster DA, 2004, MAR CHEM, V87, P59, DOI 10.1016/j.marchem.2004.02.003 Garcia-Solsona E, 2008, MAR CHEM, V109, P198, DOI 10.1016/j.marchem.2007.11.006 GIFFIN C, 1963, J GEOPHYS RES, V68, P1749, DOI 10.1029/JZ068i006p01749 Hsieh YT, 2011, J ANAL ATOM SPECTROM, V26, P1338, DOI 10.1039/c1ja10013k Ku TL, 2008, RADIOACTIV ENVIRONM, V13, P307, DOI 10.1016/S1569-4860(07)00009-5 KU TL, 1976, EARTH PLANET SC LETT, V32, P236, DOI 10.1016/0012-821X(76)90064-9 Moatar F, 2010, J RADIOANAL NUCL CH, V283, P3, DOI 10.1007/s10967-009-0001-2 Moore WS, 1996, J GEOPHYS RES-OCEANS, V101, P1321, DOI 10.1029/95JC03139 Moore WS, 2008, MAR CHEM, V109, P188, DOI 10.1016/j.marchem.2007.06.015 MOORE WS, 1995, GEOCHIM COSMOCHIM AC, V59, P4285, DOI 10.1016/0016-7037(95)00242-R Moore WS, 2003, BIOGEOCHEMISTRY, V66, P75, DOI 10.1023/B:BIOG.0000006065.77764.a0 Peterson RN, 2009, LIMNOL OCEANOGR-METH, V7, P196 Rama, 1996, GEOCHIM COSMOCHIM AC, V60, P4645 Rodellas V, 2012, J HYDROL, V466, P11, DOI 10.1016/j.jhydrol.2012.07.005 Sun Y, 1998, MAR CHEM, V62, P299, DOI 10.1016/S0304-4203(98)00019-X van Beek P, 2010, J ENVIRON RADIOACTIV, V101, P521, DOI 10.1016/j.jenvrad.2009.12.002 Waska H, 2008, J ENVIRON RADIOACTIV, V99, P1859, DOI 10.1016/j.jenvrad.2008.08.008 Geibert, Walter Rodellas, Valenti Annett, Amber van Beek, Pieter Garcia-Orellana, Jordi Hsieh, Yu-Te Masque, Pere Masque, Pere/B-7379-2008 Masque, Pere/0000-0002-1789-320X National Environmental Research Council through "UK Geotraces" [NE/H008497/1]; Scottish Alliance for GeoSciences and the Environment; MICINN (Spain) [AP2008-03044]; "Antarctic Science" research bursary, the British Antarctic Survey, NERC's Collaborative Gearing Scheme by the Natural Sciences and Engineering Research Council of Canada; "Antarctic Science" research bursary, the British Antarctic Survey, NERC's Collaborative Gearing Scheme by the University of Edinburgh; British Council-Egide "Alliance" scheme; prize ICREA Academia; Generalitat de Catalunya We would like to gratefully acknowledge support from funding agencies: W. G. and Y.-T. Hsieh from the National Environmental Research Council through "UK Geotraces" (NE/H008497/1); W. G. from the Scottish Alliance for GeoSciences and the Environment; V. R. for a PhD fellowship (AP2008-03044) from MICINN (Spain); A. A. from the "Antarctic Science" research bursary, the British Antarctic Survey, NERC's Collaborative Gearing Scheme, by the Natural Sciences and Engineering Research Council of Canada and by the University of Edinburgh; W. G., A. A., and P. v. B. received travel support from the British Council-Egide "Alliance" scheme; P. M. through the prize ICREA Academia, funded by the Generalitat de Catalunya. Thanks go to Gideon Henderson, Raja Ganeshram, and Michiel Rutgers van der Loeff; their contributions were essential to enable us to finish this manuscript. Three anonymous reviewers have provided helpful insights that contributed to improve the manuscript substantially. 0 AMER SOC LIMNOLOGY OCEANOGRAPHY WACO LIMNOL OCEANOGR-METHWe present a new method to determine Ra-226 in aqueous environmental samples, based on the rate of ingrowth of Rn-222 from Ra-226, using the radium delayed coincidence counter (RaDeCC). We use the same instrument setup that is used for the determination of Ra-223 and Ra-224. In contrast to methods published earlier, the approach does not require a modification of the counting equipment, counting separately for Ra-226, or waiting for radioactive equilibrium. We show that the calibration works from as low as 10 dpm (0.166 Bq) per sample, up to more than 1000 dpm (16.7 Bq). Although uncertainties are larger (typically around 10%) than reported uncertainties for gamma counting, liquid scintillation, or mass spectrometry at comparable activities, the simple setup, low cost, and robustness of the method make it a useful approach for underway measurements, combinations with short-lived radium isotopes, or monitoring purposes when limited funding or infrastructure is available