312 research outputs found

    Novel advanced solvent-based carbon capture pilot demonstration

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    ION Engineering’s advanced solvent is one of the leading second generation solvent systems currently under development for post-combustion carbon dioxide (CO2) capture. Throughout small scale pilot testing with coal and natural gas fired flue gas, bench scale pilot and laboratory testing, ION’s advanced solvent has consistently demonstrated 30+% reductions in regeneration energy requirements in comparison to traditional aqueous monoethanolamine (Aq-MEA). These results, in addition to CO2 solvent carrying capacities 35% higher than Aq-MEA and significantly less solvent degradation, demonstrate that ION’s CO2 capture technology has the potential to significantly reduce both capital and operating costs. ION Engineering has recently completed a 0.6 Megawatts electric (MWe) Slipstream Pilot demonstration, at the National Carbon Capture Center (NCCC) located at Southern Company’s Plant Gaston in Wilsonville, Alabama. The NCCC test facility utilizes a flue gas slipstream up to a maximum of 6,000 lb/hr from a commercially dispatched base-loaded 880-MW coal-fired boiler which supplies the NCCC test facilities. On-site work began in April 2015, with testing completed from mid-June to mid-August 2015. The overall objectives of this project are to advance ION’s solvent-based CO2 capture process at the equivalent of approximately 0.6 MWe scale pilot in order to meet the Department of Energy’s (DOE) goal for second generation solvents of ≥ 90% CO2 capture rate with 95% CO2 purity at a cost of \u3c $40/tonne CO2 captured by 2025. Additional objectives included: validation of ION’s solvent specific simulation capabilities, completion of 1,000 hours of continuous testing and an assessment of solvent lifetime. The NCCC results indicate that ION is making substantial progress towards DOE’s goals for second generation solvents. Total test hours for the program exceeded 1,100 hours. ION has also validated its solvent specific ProTreat® simulation models during parametric and steady state testing and the analyses of solvent samples for solvent lifetime studies are still in progress. Additionally, ION demonstrated that it can successfully operate its advanced solvent in a pilot unit designed for traditional Aq-MEA solvent with minimal pilot modifications. Throughout pilot testing at NCCC, ION confirmed its understanding of process improvements and analytics that will enable successful operation of its advanced solvent at significantly lower L/G circulation rates and regeneration energies. ION is currently working with national and international partners to further demonstrate its carbon capture technology in real process environments and multiple commercial settings. The data gathered from this test campaign conducted at NCCC continues to strengthen ION’s solvent technology and positive track record in executing off site test campaigns. ION anticipates that the recently completed pilot scale test at NCCC along with future projects will directly impact the state of the art of CO2 solvent technologies and facilitate advancement of CO2 capture towards commercialization and implementation of ION technology

    Classification of Singular Fibres on Rational Elliptic Surfaces in Characteristic Three

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    We determine and list all possible configurations of singular fibres on rational elliptic surfaces in characteristic three. In total, we find that 267 distinct configurations exist. This result complements Miranda and Persson's classification in characteristic zero, and Lang's classification in characteristic two.Comment: 40 Pages. Minor typos correcte

    Pharmacokinetics of once-daily extended-release tacrolimus tablets versus twice-daily capsules in de novo liver transplant

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    The pharmacokinetics of once-daily extended-release tacrolimus tablets (LCPT) in de novo liver transplantation have not been previously reported. In this phase II, randomized, open-label study, de novo liver transplant recipients were randomized to LCPT 0.07-0.13 mg/kg/day (taken once daily; n = 29) or twice-daily immediate-release tacrolimus capsules (IR-Tac) at 0.10-0.15 mg/kg/day (divided twice daily; n = 29). Subsequent doses of both drugs were adjusted to maintain tacrolimus trough concentrations of 5 to 20 ng/mL through day 90, and 5-15 ng/mL thereafter. Twenty-four-hour pharmacokinetic profiles were obtained on days 1, 7, and 14, with trough concentration and efficacy/safety monitoring through year 1. Similar proportions of patients in both groups achieved therapeutic trough concentrations on days 7 and 14 (day 7: LCPT = 78%, IR-Tac = 75%; day 14: LCPT = 86%, IR-Tac = 91%) as well as similar systemic and peak exposure. There was a robust correlation between drug concentration at time 0 and area under the concentration-time curve for both LCPT and IR-Tac (respectively, day 7: r = 0.86 and 0.79; day 14: r = 0.93 and 0.86; P \u3c .0001 for all). Dose adjustments during days 1 to 14 were frequent. Thirty-five patients completed the extended-use period. No significant differences in adverse events were seen between groups. Incidence of biopsy-proven acute rejection (LCPT = 6 and IR-Tac = 4) was similar on day 360. Between formulations, overall exposure was similar at 1 week after transplant with the characteristic delayed-release pharmacokinetic profile of LCPT demonstrated in this novel population. These data support further investigation of the safety and efficacy of LCPT in de novo liver transplantation

    High-Velocity Line Forming Regions in the Type Ia Supernova 2009ig

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    We report measurements and analysis of high-velocity (> 20,000 km/s) and photospheric absorption features in a series of spectra of the Type Ia supernova (SN) 2009ig obtained between -14d and +13d with respect to the time of maximum B-band luminosity. We identify lines of Si II, Si III, S II, Ca II and Fe II that produce both high-velocity (HVF) and photospheric-velocity (PVF) absorption features. SN 2009ig is unusual for the large number of lines with detectable HVF in the spectra, but the light-curve parameters correspond to a slightly overluminous but unexceptional SN Ia (M_B = -19.46 mag and Delta_m15 (B) = 0.90 mag). Similarly, the Si II lambda_6355 velocity at the time of B-max is greater than "normal" for a SN Ia, but it is not extreme (v_Si = 13,400 km/s). The -14d and -13d spectra clearly resolve HVF from Si II lambda_6355 as separate absorptions from a detached line forming region. At these very early phases, detached HVF are prevalent in all lines. From -12d to -6d, HVF and PVF are detected simultaneously, and the two line forming regions maintain a constant separation of about 8,000 km/s. After -6d all absorption features are PVF. The observations of SN 2009ig provide a complete picture of the transition from HVF to PVF. Most SN Ia show evidence for HVF from multiple lines in spectra obtained before -10d, and we compare the spectra of SN 2009ig to observations of other SN. We show that each of the unusual line profiles for Si II lambda_6355 found in early-time spectra of SN Ia correlate to a specific phase in a common development sequence from HVF to PVF.Comment: 19 pages, 11figures, 4 tables, submitted to Ap

    How to Advance Legal Education for Future Public Health Professionals.

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    Recent scholarship has advocated for schools and programs of public health (SPPHs) to move public health law from the periphery to the core of the public health curriculum, in recognition of law’s role as a fundamental driver of health outcomes. 1,2 The Five Essential Public Health Law Services—developed through a transdisciplinary collaboration of public health practitioners, researchers, advocates, and attorneys—emphasize that competency in public health law requires much more than the ability to summarize key statutes or court decisions.3 Rather, “[p]eople working in public health—whether in agencies, non-governmental organizations, health systems, research and even biomedical sciences— can expect to carry out a variety of functions that involve law, frequently without the assistance or even the involvement of lawyers.”1 These functions include the design, development, implementation, enforcement, and evaluation of legal interventions (to prevent drug overdoses, ensure food safety, contain infectious disease outbreaks, and much more)—functions that have become more complex and politically charged, but no less important, since the onset of the COVID-19 pandemic

    Scope for Credit Risk Diversification

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    This paper considers a simple model of credit risk and derives the limit distribution of losses under different assumptions regarding the structure of systematic risk and the nature of exposure or firm heterogeneity. We derive fat-tailed correlated loss distributions arising from Gaussian risk factors and explore the potential for risk diversification. Where possible the results are generalised to non-Gaussian distributions. The theoretical results indicate that if the firm parameters are heterogeneous but come from a common distribution, for sufficiently large portfolios there is no scope for further risk reduction through active portfolio management. However, if the firm parameters come from different distributions, then further risk reduction is possible by changing the portfolio weights. In either case, neglecting parameter heterogeneity can lead to underestimation of expected losses. But, once expected losses are controlled for, neglecting parameter heterogeneity can lead to overestimation of risk, whether measured by unexpected loss or value-at-risk

    Reverberation Mapping of the Kepler-Field AGN KA1858+4850

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    KA1858+4850 is a narrow-line Seyfert 1 galaxy at redshift 0.078 and is among the brightest active galaxies monitored by the Kepler mission. We have carried out a reverberation mapping campaign designed to measure the broad-line region size and estimate the mass of the black hole in this galaxy. We obtained 74 epochs of spectroscopic data using the Kast Spectrograph at the Lick 3-m telescope from February to November of 2012, and obtained complementary V-band images from five other ground-based telescopes. We measured the H-beta light curve lag with respect to the V-band continuum light curve using both cross-correlation techniques (CCF) and continuum light curve variability modeling with the JAVELIN method, and found rest-frame lags of lag_CCF = 13.53 (+2.03, -2.32) days and lag_JAVELIN = 13.15 (+1.08, -1.00) days. The H-beta root-mean-square line profile has a width of sigma_line = 770 +/- 49 km/s. Combining these two results and assuming a virial scale factor of f = 5.13, we obtained a virial estimate of M_BH = 8.06 (+1.59, -1.72) x 10^6 M_sun for the mass of the central black hole and an Eddington ratio of L/L_Edd ~ 0.2. We also obtained consistent but slightly shorter emission-line lags with respect to the Kepler light curve. Thanks to the Kepler mission, the light curve of KA1858+4850 has among the highest cadences and signal-to-noise ratios ever measured for an active galactic nucleus; thus, our black hole mass measurement will serve as a reference point for relations between black hole mass and continuum variability characteristics in active galactic nuclei

    Honeybee linguistics—a comparative analysis of the waggle dance among species of Apis

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    All honeybees use the waggle dance to recruit nestmates. Studies on the dance precision of Apis mellifera have shown that the dance is often imprecise. Two hypotheses have been put forward aimed at explaining this imprecision. The first argues that imprecision in the context of foraging is adaptive as it ensures that the dance advertises the same patch size irrespective of distance. The second argues that the bees are constrained in their ability to be more precise, especially when the source is nearby. Recent studies have found support for the latter hypothesis but not for the “tuned-error” hypothesis, as the adaptive hypothesis became known. Here we investigate intra-dance variation among Apis species. We analyse the dance precision of A. florea, A. dorsata, and A. mellifera in the context of foraging and swarming. A. mellifera performs forage dances in the dark, using gravity as point of reference, and in the light when dancing for nest sites, using the sun as point of reference. Both A. dorsata and A. florea are open-nesting species; they do not use a different point of reference depending on context. A. florea differs from both A. mellifera and A. dorsata in that it dances on a horizontal surface and does not use gravity but instead “points” directly toward the goal when indicating direction. Previous work on A. mellifera has suggested that differences in dance orientation and point of reference can affect dance precision. We find that all three species improve dance precision with increasing waggle phase duration, irrespective of differences in dance orientation, and point of reference. When dancing for sources nearby, dances are highly variable. When the distance increases, dance precision converges. The exception is dances performed by A. mellifera on swarms. Here, dance precision decreases as the distance increases. We also show that the size of the patch advertised increases with increasing distance, contrary to what is predicted under the tuned-error hypothesis

    Submucosal Gland Myoepithelial Cells Are Reserve Stem Cells That Can Regenerate Mouse Tracheal Epithelium

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    The mouse trachea is thought to contain two distinct stem cell compartments that contribute to airway repair-basal cells in the surface airway epithelium (SAE) and an unknown submucosal gland (SMG) cell type. Whether a lineage relationship exists between these two stem cell compartments remains unclear. Using lineage tracing of glandular myoepithelial cells (MECs), we demonstrate that MECs can give rise to seven cell types of the SAE and SMGs following severe airway injury. MECs progressively adopted a basal cell phenotype on the SAE and established lasting progenitors capable of further regeneration following reinjury. MECs activate Wnt-regulated transcription factors (Lef-1/TCF7) following injury and Lef-1 induction in cultured MECs promoted transition to a basal cell phenotype. Surprisingly, dose-dependent MEC conditional activation of Lef-1 in vivo promoted self-limited airway regeneration in the absence of injury. Thus, modulating the Lef-1 transcriptional program in MEC-derived progenitors may have regenerative medicine applications for lung diseases
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