212 research outputs found
Fluoride Adsorption Utilizing Magnetite Impregnated Bone Char
Reduce fluoride concentrations in contaminated mine water from 10 mg/L to below 2 mg/L. Design an energy efficient and sustainable system with a minimal carbon footprint. Recover Fluoride as a saleable produc
Georgia Aquarium Design Space Analysis and Optimization
AbstractThe Ocean Voyager exhibit residing at the Georgia Aquarium Inc. (GAI) is one of the largest reef gallon aquariums in the world, with a capacity greater than 6.2M gallons. Reef aquariums are closed systems and must compensate by ‘turning over’ their complete volume of water many times a day through biological, chemical, and mechanical filtration. Due to the Georgia Aquarium being a non-profit organization, GAI sought to investigate ways to maximize efficiency and lower operating costs. This paper will focus on using low-cost software solutions to perform trade space analyses and optimization directed towards the Ocean Voyager exhibit and related GA Aquarium life support and energy systems.The software solution herein demonstrates a top-down System of Systems (SoS) to subsystem modeling approach that provides decision makers with interdisciplinary dashboard-level tools to visualize system design. The goal of the analysis is to provide executive level decision-making support for designing or enhancing existing complex systems and SoS. The analysis was performed as a capstone project by Georgia Tech graduate students progressing from cradle to finish in just 9 weeks to show the benefits of systems engineering to Georgia Aquarium staff. Integrating software SE tools into a single, aggregate model enables project engineers and decision makers to direct design directions with confidence
Geriatric Emergency Department Innovations: Transitional Care Nurses and Hospital Use
OBJECTIVES: To examine the effect of an emergency department (ED)-based transitional care nurse (TCN) on hospital use. DESIGN: Prospective observational cohort. SETTING: Three U.S. (NY, IL, NJ) EDs from January 1, 2013, to June 30, 2015. PARTICIPANTS: Individuals aged 65 and older in the ED (N = 57,287). INTERVENTION: The intervention was first TCN contact. Controls never saw a TCN during the study period. MEASUREMENTS: We examined sociodemographic and clinical characteristics associated with TCN use and outcomes. The primary outcome was inpatient admission during the index ED visit (admission on Day 0). Secondary outcomes included cumulative 30-day admission (any admission on Days 0-30) and 72-hour ED revisits. RESULTS: A TCN saw 5,930 (10%) individuals, 42% of whom were admitted. After accounting for observed selection bias using entropy balance, results showed that when compared to controls, TCN contact was associated with lower risk of admission (site 1: -9.9% risk of inpatient admission, 95% confidence interval (CI) = -12.3% to -7.5%; site 2: -16.5%, 95% CI = -18.7% to -14.2%; site 3: -4.7%, 95% CI = -7.5% to -2.0%). Participants with TCN contact had greater risk of a 72-hour ED revisit at two sites (site 1: 1.5%, 95% CI = 0.7-2.3%; site 2: 1.4%, 95% CI = 0.7-2.1%). Risk of any admission within 30 days of the index ED visit also remained lower for TCN patients at both these sites (site 1: -7.8%, 95% CI = -10.3% to -5.3%; site 2: -13.8%, 95% CI = -16.1% to -11.6%). CONCLUSION: Targeted evaluation by geriatric ED transitions of care staff may be an effective delivery innovation to reduce risk of inpatient admission
Confined Population III Enrichment and the Prospects for Prompt Second-Generation Star Formation
It is widely recognized that nucleosynthetic output of the first, Population
III supernovae was a catalyst defining the character of subsequent stellar
generations. Most of the work on the earliest enrichment was carried out
assuming that the first stars were extremely massive and that the associated
supernovae were unusually energetic, enough to completely unbind the baryons in
the host cosmic minihalo and disperse the synthesized metals into the
intergalactic medium. Recent work, however, suggests that the first stars may
in fact have been somewhat less massive, with a characteristic mass scale of a
few tens of solar masses. We present a cosmological simulation following the
transport of the metals synthesized in a Population III supernova assuming that
it had an energy of 1e51 ergs, compatible with standard Type II supernovae. A
young supernova remnant is inserted in the first star's relic HII region in the
free expansion phase and is followed for 40 Myr employing adaptive mesh
refinement and Lagrangian tracer particle techniques. The supernova remnant
remains partially trapped within the minihalo and the thin snowplow shell
develops pronounced instability and fingering. Roughly half of the ejecta turn
around and fall back toward the center of the halo, with 1% of the ejecta
reaching the center in 30 kyr and 10% in 10 Myr. The average metallicity of the
combined returning ejecta and the pristine filaments feeding into the halo
center from the cosmic web is 0.001 - 0.01 Z_sun, but the two remain unmixed
until accreting onto the central hydrostatic core that is unresolved at the end
of the simulation. We conclude that if Population III stars had less extreme
masses, they promptly enriched the host minihalos with metals and triggered
Population II star formation.Comment: 13 pages, 8 figure
Sequencing of 15 622 Gene-bearing BACs Clarifies the Gene-dense Regions of the Barley Genome
Barley (Hordeum vulgare L.) possesses a large and highly repetitive genome of 5.1 Gb that has hindered the development of a complete sequence. In 2012, the International Barley Sequencing Consortium released a resource integrating whole-genome shotgun sequences with a physical and genetic framework. However, because only 6278 bacterial artificial chromosome (BACs) in the physical map were sequenced, fine structure was limited. To gain access to the gene-containing portion of the barley genome at high resolution, we identified and sequenced 15 622 BACs representing the minimal tiling path of 72 052 physical-mapped gene-bearing BACs. This generated ~1.7 Gb of genomic sequence containing an estimated 2/3 of all Morex barley genes. Exploration of these sequenced BACs revealed that although distal ends of chromosomes contain most of the gene-enriched BACs and are characterized by high recombination rates, there are also gene-dense regions with suppressed recombination. We made use of published map-anchored sequence data from Aegilops tauschii to develop a synteny viewer between barley and the ancestor of the wheat D-genome. Except for some notable inversions, there is a high level of collinearity between the two species. The software HarvEST:Barley provides facile access to BAC sequences and their annotations, along with the barley–Ae. tauschii synteny viewer. These BAC sequences constitute a resource to improve the efficiency of marker development, map-based cloning, and comparative genomics in barley and related crops. Additional knowledge about regions of the barley genome that are gene-dense but low recombination is particularly relevant
FR II radio galaxies at low frequencies I : morphology, magnetic field strength and energetics
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. ©: 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.Due to their steep spectra, low-frequency observations of FR II radio galaxies potentially provide key insights in to the morphology, energetics and spectrum of these powerful radio sources. However, limitations imposed by the previous generation of radio interferometers at metre wavelengths has meant that this region of parameter space remains largely unexplored. In this paper, the first in a series examining FR IIs at low frequencies, we use LOFAR observations between 50 and 160 MHz, along with complementary archival radio and X-ray data, to explore the properties of two FR II sources, 3C452 and 3C223. We find that the morphology of 3C452 is that of a standard FR II rather than of a double-double radio galaxy as had previously been suggested, with no remnant emission being observed beyond the active lobes. We find that the low-frequency integrated spectra of both sources are much steeper than expected based on traditional assumptions and, using synchrotron/inverse-Compton model fitting, show that the total energy content of the lobes is greater than previous estimates by a factor of around 5 for 3C452 and 2 for 3C223. We go on to discuss possible causes of these steeper than expected spectra and provide revised estimates of the internal pressures and magnetic field strengths for the intrinsically steep case. We find that the ratio between the equipartition magnetic field strengths and those derived through synchrotron/inverse-Compton model fitting remains consistent with previous findings and show that the observed departure from equipartition may in some cases provide a solution to the spectral versus dynamical age disparity.Peer reviewe
Defining optimal soybean seeding rates and associated risk across North America
Soybean [Glycine max (L.) Merr.] seeding rate research across North America is typically conducted in small geo-political regions where environmental effects on the seeding rate × yield relationship are minimized. Data from 211 individual field studies (∼21,000 data points, 2007–2017) were combined from across North America ranging in yield from 1,000– 7,500 kg ha−1. Cluster analysis was used to stratify each individual field study into similar environmental (soil × climate) clusters and into high (HYL), medium (MYL), and low (LYL) yield levels. Agronomically optimal seeding rates (AOSR) were calculated and Monte Carlo risk analysis was implemented. Within the two northern most clusters the AOSR was higher in the LYL followed by the MYL and then HYL. Within the farthest south cluster, a relatively small (±15,000 seeds ha−1) change in seeding rate from the MYL was required to reach the AOSR of the LYL and HYL, respectively. The increase in seeding rate to reach the LYL AOSR was relatively greater (5x) than the decrease to reach the HYL AOSR within the northern most cluster. Regardless, seeding rates below the AOSR presented substantial risk and potential yield loss, while seeding rates above provided slight risk reduction and yield increases. Specific to LYLs and MYLs, establishing and maintaining an adequate plant stand until harvest maximized yield regardless of the seeding rate, while maximizing seed number was important with lower seeding rates. These findings will help growers manage their soybean seed investment by adjusting seeding rates based upon the productivity of the environment.Fil: Gaspar, Adam P.. Dow Agrosciences Argentina Sociedad de Responsabilidad Limitada.; ArgentinaFil: Mourtzinis, Spyridon. University of Wisconsin; Estados UnidosFil: Kyle, Don. Dow Agrosciences Argentina Sociedad de Responsabilidad Limitada.; ArgentinaFil: Galdi, Eric. Dow Agrosciences Argentina Sociedad de Responsabilidad Limitada.; ArgentinaFil: Lindsey, Laura E.. Ohio State University; Estados UnidosFil: Hamman, William P.. Ohio State University; Estados UnidosFil: Matcham, Emma G. University of Wisconsin; Estados UnidosFil: Kandel, Hans J.. North Dakota State University; Estados UnidosFil: Schmitz, Peder. North Dakota State University; Estados UnidosFil: Stanley, Jordan D.. North Dakota State University; Estados UnidosFil: Schmidt, John P.. Dow Agrosciences Argentina Sociedad de Responsabilidad Limitada.; ArgentinaFil: Mueller, Daren S.. University of Iowa; Estados UnidosFil: Nafziger, Emerson D.. University of Illinois; Estados UnidosFil: Ross, Jeremy. University of Arkansas for Medical Sciences; Estados UnidosFil: Carter, Paul R.. Dow Agrosciences Argentina Sociedad de Responsabilidad Limitada.; ArgentinaFil: Varenhorst, Adam J.. University of South Dakota; Estados UnidosFil: Wise, Kiersten A.. University of Kentucky; Estados UnidosFil: Ciampitti, Ignacio Antonio. Kansas State University; Estados UnidosFil: Carciochi, Walter Daniel. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Mar del Plata; Argentina. Kansas State University; Estados UnidosFil: Chilvers, Martin I.. Michigan State University; Estados UnidosFil: Hauswedell, Brady. University of South Dakota; Estados UnidosFil: Tenuta, Albert U.. University of Guelph; CanadáFil: Conley, Shawn P.. University of Wisconsin; Estados Unido
Cold, clumpy accretion onto an active supermassive black hole
Supermassive black holes in galaxy centres can grow by the accretion of gas, liberating energy that might regulate star formation on galaxy-wide scales. The nature of the gaseous fuel reservoirs that power black hole growth is nevertheless largely unconstrained by observations, and is instead routinely simplified as a smooth, spherical inflow of very hot gas. Recent theory and simulations instead predict that accretion can be dominated by a stochastic, clumpy distribution of very cold molecular clouds - a departure from the "hot mode" accretion model - although unambiguous observational support for this prediction remains elusive. Here we report observations that reveal a cold, clumpy accretion flow towards a supermassive black hole fuel reservoir in the nucleus of the Abell 2597 Brightest Cluster Galaxy (BCG), a nearby (redshift z=0.0821) giant elliptical galaxy surrounded by a dense halo of hot plasma. Under the right conditions, thermal instabilities can precipitate from this hot gas, producing a rain of cold clouds that fall toward the galaxy's centre, sustaining star formation amid a kiloparsec-scale molecular nebula that inhabits its core. The observations show that these cold clouds also fuel black hole accretion, revealing "shadows" cast by the molecular clouds as they move inward at about 300 kilometres per second towards the active supermassive black hole in the galaxy centre, which serves as a bright backlight. Corroborating evidence from prior observations of warmer atomic gas at extremely high spatial resolution, along with simple arguments based on geometry and probability, indicate that these clouds are within the innermost hundred parsecs of the black hole, and falling closer towards it
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