2,803 research outputs found
Advanced and novel modeling techniques for simulation, optimization and monitoring chemical engineering tasks with refinery and petrochemical unit applications
Engineers predict, optimize, and monitor processes to improve safety and profitability. Models automate these tasks and determine precise solutions. This research studies and applies advanced and novel modeling techniques to automate and aid engineering decision-making. Advancements in computational ability have improved modeling software’s ability to mimic industrial problems. Simulations are increasingly used to explore new operating regimes and design new processes. In this work, we present a methodology for creating structured mathematical models, useful tips to simplify models, and a novel repair method to improve convergence by populating quality initial conditions for the simulation’s solver. A crude oil refinery application is presented including simulation, simplification tips, and the repair strategy implementation. A crude oil scheduling problem is also presented which can be integrated with production unit models. Recently, stochastic global optimization (SGO) has shown to have success of finding global optima to complex nonlinear processes. When performing SGO on simulations, model convergence can become an issue. The computational load can be decreased by 1) simplifying the model and 2) finding a synergy between the model solver repair strategy and optimization routine by using the initial conditions formulated as points to perturb the neighborhood being searched. Here, a simplifying technique to merging the crude oil scheduling problem and the vertically integrated online refinery production optimization is demonstrated. To optimize the refinery production a stochastic global optimization technique is employed. Process monitoring has been vastly enhanced through a data-driven modeling technique Principle Component Analysis. As opposed to first-principle models, which make assumptions about the structure of the model describing the process, data-driven techniques make no assumptions about the underlying relationships. Data-driven techniques search for a projection that displays data into a space easier to analyze. Feature extraction techniques, commonly dimensionality reduction techniques, have been explored fervidly to better capture nonlinear relationships. These techniques can extend data-driven modeling’s process-monitoring use to nonlinear processes. Here, we employ a novel nonlinear process-monitoring scheme, which utilizes Self-Organizing Maps. The novel techniques and implementation methodology are applied and implemented to a publically studied Tennessee Eastman Process and an industrial polymerization unit
Dependence of Nebular Heavy-Element Abundance on H I Content for Spiral Galaxies
We analyze the galactic H I content and nebular log(O/H) for 60 spiral
galaxies in the Moustakas et al. (2006) spectral catalog. After correcting for
the mass-metallicity relationship, we show that the spirals in cluster
environments show a positive correlation for log(O/H) on DEF, the galactic H I
deficiency parameter, extending the results of previous analyses of the Virgo
and Pegasus I clusters. Additionally, we show for the first time that galaxies
in the field obey a similar dependence. The observed relationship between H I
deficiency and galactic metallicity resembles similar trends shown by
cosmological simulations of galaxy formation including inflows and outflows.
These results indicate the previously observed metallicity-DEF correlation has
a more universal interpretation than simply a cluster's effects on its member
galaxies. Rather, we observe in all environments the stochastic effects of
metal-poor infall as minor mergers and accretion help to build giant spirals.Comment: Accepted for publication in Ap
Characterizing hormesis and the in vitro effects of sub-lethal fungicide exposure in sclerotinia homoeocarpa
Dollar spot, caused by Sclerotinia homoeocarpa F.T. Bennett, is the most economically important disease of turfgrass. Dollar spot reduces aesthetics and playability of turfgrass, and when left uncontrolled can result in plant death and weed encroachment. Sterol demethylase inhibiting (DMI) fungicides are valuable for dollar spot control due to their broad spectrum of activity with single applications. Previous studies have shown sub-lethal concentrations of fungicides can cause plant pathogens to exhibit hormesis. The first goal of this research was to evaluate the effects of sub-lethal doses of DMI fungicides on the mycelial growth of a range of S. homoeocarpa isolates via an in vitro fungicide assay. The second goal was to examine the impact of sub-lethal doses of DMI fungicides on the production of oxalic acid in S. homoeocarpa. The third goal was to determine the effects of low doses of DMI fungicides on the disease severity of resistant and sensitive populations of S. homoeocarpa on creeping bentgrass. Sub-lethal concentrations of DMI fungicides did not cause significant increases of mycelial growth in vitro when compared to mycelial growth of untreated isolates. A method to detect oxalic acid via high performance liquid chromatography was developed in this research. Oxalic acid concentrations were greatest when isolates were treated with a high rate of DMI fungicides. In the greenhouse, area under the disease progress curve (AUDPC) was consistently increased by a sub-lethal rate of DMI fungicides when compared to untreated inoculum. A sublethal rate of DMI fungicides consistently caused increased mean disease severity as early as 21 days after treatment. Results of this study suggest sub-lethal concentrations of fungicides may induce hormesis in S. homoeocarpa, resulting in increased dollar spot pressure in creeping bentgrass.Includes bibliographical reference
Judicial Disqualification on Appeal
Adjudication by an impartial decision maker is one of the cornerstones of due process. The interest is so fundamental that constitutional due process guards against even the appearance of partiality, and federal judges are statutorily required to disqualify themselves in any proceeding in which their impartiality “might reasonably be questioned.” Courts and scholars alike have struggled with what it means to “reasonably question” a judge’s impartiality. That question has taken on greater salience in recent years, as deepening partisan divisions have increasingly led parties to express skepticism of judicial neutrality.
When a party files a motion to disqualify a judge based on the appearance of partiality, that motion is commonly ruled upon by the very judge whose impartiality is being questioned. The ability to appeal the denial of a disqualification motion plays therefore plays a key role in maintaining public confidence in the judiciary. Appellate review offers a third-party evaluation of the judge’s appearance of impartiality (often the first third-party review), and it brings in the benefit of a larger panel to evaluate the underlying ruling.
In spite of the importance of appellate review, the procedures by which judicial disqualification will be reviewed are far from clear. This Article explores the procedural aspects of appellate review of judicial disqualification orders and works to reconcile the current inconsistencies in federal practice. Ultimately, the article recommends that the federal courts standardize appellate review of disqualification orders to minimize confusion and promote confidence in an impartial judiciary
Building the Rust Fast Track System for Identifying Asian Soybean Rust in Iowa
Asian soybean rust is a serious soybean leaf disease not yet discovered in Iowa. There are common soybean leaf diseases that may be confused with Asian soybean rust. To achieve accurate and prompt identification of Asian soybean rust throughout the state, the Iowa Soybean Rust Fast Track system was created. This unique system makes use of hundreds of private agricultural professionals throughout Iowa and 40 Iowa State University Extension field personnel to filter out suspected soybean rust samples that are common soybean leaf diseases, thereby ensuring that the ISU Plant Disease clinic is not inundated with minor diseases of soybean
A Review of Thick-Billed Murre Banding in the Canadian Arctic, 1950–2010
Banding of Thick-billed Murres Uria lomvia in the Canadian Arctic was initiated by L.M. Tuck in the 1950s, when he visited three of the largest breeding colonies in Canada. Up to 2010, banding had been carried out at eight of the 10 major breeding colonies, with totals of more than 1000 birds banded at Coburg Island and Cape Hay, Bylot Island, in the High Arctic and at Digges Sound and Coats Island in northern Hudson Bay. Because murres are long-lived birds, large-scale banding can continue to provide useful results for decades. A total of about 89 000 bandings in Arctic Canada resulted in 1757 usable recoveries up to 2010, the vast majority of which were birds killed by hunters in West Greenland or Newfoundland and Labrador. There was no apparent change in the large-scale geographical pattern of recoveries over the period reviewed, but the proportion of bands recovered has fallen. Several periods of higher- or lower-than-expected recoveries can be attributed to particular events: anomalous ice conditions, intensive gill-net fisheries, and oiling at sea. Thus, banding provided a useful tool not only for identifying migration and wintering areas, but also for identifying transient sources of increased mortality.Les débuts du baguage des guillemots de Brünnich Uria lomvia dans l’Arctique canadien remontent aux années 1950, sous l’égide de L.M. Tuck à l’occasion de sa visite de trois des plus grandes colonies de nidification au Canada. Jusqu’en 2010, le baguage a été effectué à huit des dix grandes colonies de nidification, pour un total de plus de 1 000 oiseaux bagués à l’île Coburg, à cap Hay et à l’île Bylot, dans l’Extrême-Arctique, ainsi qu’au détroit de Digges et à l’île Coats, dans le nord de la baie d’Hudson. Puisque les guillemots de Brünnich sont des oiseaux qui vivent longtemps, le baguage à grande échelle peut donner des résultats pendant des années. Jusqu’en 2010, les quelque 89 000 baguages effectués dans l’Arctique canadien se sont traduits par 1 757 récupérations d’oiseaux utilisables, la vaste majorité d’entre eux ayant été tuée par des chasseurs de l’ouest du Groenland ou de Terre-Neuve-Labrador. Il n’y avait aucun changement apparent dans le modèle géographique à grande échelle des oiseaux récupérés au cours de la période examinée, mais la proportion de bagues récupérées a diminué. Plusieurs périodes de récupérations plus grandes ou moins grandes que prévu peuvent être attribuées à des événements particuliers : un état anormal des glaces, la pêche intensive au filet maillant et le mazoutage en mer. Par conséquent, le baguage a représenté un outil utile non seulement pour déterminer les lieux de migration et les aires d’hivernage, mais aussi pour repérer les sources transitoires de mortalité accrue.Mots clés : L.M. Tuck, guillemot de Brünnich, Uria lomvia, chasse, baguage, population
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