2,383 research outputs found
Analysis of a space--time hybridizable discontinuous Galerkin method for the advection--diffusion problem on time-dependent domains
This paper presents the first analysis of a space--time hybridizable
discontinuous Galerkin method for the advection--diffusion problem on
time-dependent domains. The analysis is based on non-standard local trace and
inverse inequalities that are anisotropic in the spatial and time steps. We
prove well-posedness of the discrete problem and provide a priori error
estimates in a mesh-dependent norm. Convergence theory is validated by a
numerical example solving the advection--diffusion problem on a time-dependent
domain for approximations of various polynomial degree
Pore-Scale Analysis of DNAPL Dissolution and Biomass Distribution
A comparison of equilibrium and non-equilibrium dissolution of tetrachloroethylene (PCE) was conducted to ascertain how PCE saturation, individual blob properties (volume, surface area, sphericity), and PCE occupied pores are affected by two distinct dissolution regimes. One-dimensional columns were imaged at various dissolution stages using high resolution (~10 um) synchrotron x-ray tomography (XT) and image subvolumes were analyzed using a series of grain, pore network structure, and blob analysis algorithms. An analysis of algorithm-generated data was conducted to determine grain and pore statistics, PCE saturation and individual blob properties, and correlations between PCE blobs and pore network structure. Grain and pore data demonstrated an accurate and consistent segmentation of grains and pores across experiments and a consistent packing between columns. PCE removal rates with pore volumes flushed in both equilibrium and nonequilibrium experiments were consistent until arrival of the primary dissolution front in equilibrium columns. Arrival of the primary dissolution front and number of pore volumes required to completely remove PCE from equilibrium experiments matched well with theoretical predictions. Nonequilibrium dissolution rates varied during the course of the experiment, with increased dissolution observed near the conclusion of the experiments. Blob properties within the equilibrium columns remained relatively constant for all dissolution steps prior to the arrival of the primary dissolution front. Changes in pore-level blob properties in the nonequilibrium experiments were correlated to small perturbations in the mass transfer rates. Deviations in mass transfer rates within the subvolumes occurred over relatively short timescales and are most likely due to the inability to image and analyze a representative elementary volume (REV). XT was also used to investigate the feasibility of imaging biomass within a porous media system. Lugol’s iodine was used to dope the biomass and mass attenuation histograms were compared to those of an undoped biomass system and an abiotic system imaged with and without Lugol’s iodine filling the pore space. After pre-processing with an anisotropic diffusion program, the biomass could be identified within void space of the biotic columns. This insight will aid in the development of XT in exploring the effects of biomass on pore-scale aqueous flow paths
Breast Lesion Localization: Savi Scout
Breast Lesion Localization: Savi Scout
Madison Keegan
Faculty Advisor: Dr. Elaine Halesey, Ed.D., R.T.(R)(QM)
The Savi Scout is a localization procedure used to help identify non-palpable breast lesions under mammographic or ultrasound guidance, by way of placement of a non-radioactive reflector through a delivery system. The modality of mammography uses screening and diagnostic exams by creating images of the breast to better visualize anatomy as well as possible lesions. The radiographic detail determines the type of breast tissue such as fatty, dense, or extremely dense and with age the tissue type can change. Non-palpable breast lesions are identified with imaging of the breast, using procedures other than the Savi Scout such as: wire guided localization, radioactive seed, magnetic seed, radiofrequency identification, and hematoma ultrasound guided. The Savi Scout localization procedure can be completed up to 30 days prior to surgery, and is located after placement using a hand piece and guidance system. Location is determined by the reflector emitting a certain frequency based on proximity to the reflector, and when compared to the more common procedure of wire guided localization, there is no statistical difference as the mean tumor volume, negative margin rate, and re-excision rate. The Savi Scout is an FDA approved procedure that is efficient and is becoming more commonly used.
Keywords: Savi Scout, Non-palpable Breast Lesions, Mammography, Reflector, Localization, Procedure, Wire Guided localizationhttps://digitalcommons.misericordia.edu/medimg_seniorposters/1001/thumbnail.jp
Chemical Equilibration in Hadronic Collisions
We study chemical equilibration in out-of-equilibrium Quark-Gluon Plasma
using the first principles method of QCD effective kinetic theory, accurate at
weak coupling. In longitudinally expanding systems--relevant for relativistic
nuclear collisions--we find that for realistic couplings chemical equilibration
takes place after hydrodynamization, but well before local thermalization. We
estimate that hadronic collisions with final state multiplicities
live long enough to reach approximate
chemical equilibrium, which is consistent with the saturation of strangeness
enhancement observed in proton-proton, proton-nucleus and nucleus-nucleus
collisions.Comment: 7 pages, 3 figures, see also our companion paper arXiv:1811.03068, v2
small changes, published versio
Elsewhere Lies Its Meaning: The Vagaries of Kalīla and Dimna’s Reception
alīla and Dimna was translated from Pahlavi into Arabic in the 8th century AD by Ibn al-Muqaffaʿ, and it became an influential text in numerous literary cultures. Copyists in the Arabic manuscript tradition acted as coauthors, changing the text in ways both large and small. The modern scholarly tradition tends to see Kalīla and Dimna as part of a Fürstenspiegel genre or as an example of animal fables. What these categorizations overlook is the variegated medieval reception of the text, which was more multifaceted than is generally appreciated. The unruliness of the text's reception is the theme of this article, which explores the ways in which medieval readers categorized and reinterpreted Kalīla and Dimna over centuries, with special attention to Ibn al-Habbāriyya's late 11th-century dramatization of the divergent interpretations of Kalīla and Dimna. The article reveals that the interpreters of this text reconfigured its generic affiliation, making it a Quranic competitor, a repository of proverbs, an allegory for the soul, a source of law, and a model for storytelling that imparts practical wisdom
Modeling of river hydrodynamics and active cap effectiveness in the Anacostia River
The Anacostia Active Capping Project (AACP) is a United States Environmental Protection Agency (EPA) funded initiative to develop and implement, on a field scale, active capping barrier technologies. Overseen by the Hazardous Substance Research Center, South and Southwest (HSRC), the AACP plans to demonstrate the ability of active capping barrier technologies to prevent the migration of contaminants from the sediment bed to the overlying water column of the Anacostia River. The demonstration project will involve the placement and monitoring of four individual types of capping materials (apatite, Aquablok, coke breeze, and sand) and the monitoring of one control (i.e. uncapped) area. An integral part of this capping/monitoring effort will be the use of the Model for the Assessment and Remediation of Sediments (MARS) to project long term cap stability and effectiveness. Developed by the Electric Power Research Institute (EPRI), MARS allows for the modeling of river hydrodynamics, sediment transport, chemical fate/transport, and contaminated sediment remediation with one stand-alone model. It is the object of this research to not only model river characteristics and cap effectiveness but to also identify those areas of the MARS model which could benefit from revisions to allow for future active capping barrier simulations. Model projections illustrate the demonstration area as being a zone of sediment deposition during normal flow events. Furthermore, MARS predicts Aquablok and coke breeze as being the most effective capping barriers when considering PAH migration from the sediment column to the overlying water body. Apatite displayed little PAH contaminant retardation as this barrier is being implemented in the AACP in an attempt to precipitate heavy metals from the sediment and pore water
Dreams in Early Modern England: “Visions of the Night.”
In Dreams in Early Modern England, Janine Rivière explores the
frames through which early modern people experienced and conceptualized
their dreams. Through these frames, she aims to resist the
anachronistic psychological and psychoanalytic approaches that, for
her, have characterized studies of early modern dreaming
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