16 research outputs found
Extension of the Continuity Constraint Algorithm to Variable-Density Flow Simulation
One class of problems commonly encountered in the study of computational fluid dynamics involves the flow of fluids with variable density. Such flows are characterized by density variations too large for the assumption used in most incompressible Navier-Stokes formulations, that small changes in density are linearly proportional to changes in temperature, to be valid. Unlike fully compressible flows, such as the high-speed flow of gases, variable-density flows are often characterized by low Mach numbers. Examples of such flows include 1) combustion problems, where significant density variations may arise due to the large temperature differences present, and 2) flows involving liquids, such as refrigerated hydrogen, whose density varies significantly over small temperature differences.
While fully compressible algorithms can be used to solve problems involving variable- density flows, such calculations are computationally inefficient. As an alternative, a modified version of the Continuity Constraint Algorithm of Williams has been developed for solving problems involving fluids with variable-density. Originally developed as an inexact method for solving incompressible flow problems, the Continuity Constraint Algorithm belongs to a general class of computational algorithms, normally referred to as either “pressure-projection” or “pressure-correction” methods.
This work derives a variable-density form of the computational algorithm and presents the results of its application to a series of two-dimensional benchmark problems. The first of which involves the buoyancy-induced flow of air inside a closed cavity. Results of these initial algorithm tests showed, that while adequate steady-state solutions were obtained for cases corresponding to Rayleigh number values of 104 to 107, the algorithm experienced some computational difficulties in reaching steady-state conditions.
A second series of calculations were performed to emphasize the effects of the variable- density assumption. For these calculations, solutions for the buoyancy-induced flow of liquid hydrogen inside a closed cavity at a Rayleigh number value of 1010 were generated using both the variable-density and incompressible versions of the Continuity Constraint Algorithm. Like the initial algorithm tests, a number of computational difficulties (some of which were significant) were encountered. Examination of the steady-state results, determined via visual inspection of the temporal evolution of velocity and temperature fields, from these analyses showed significant differences between the variable-density and INS solutions
Recommended from our members
Association of PCOA scores; GPA; and other factors with NAPLEX Pass Rate: A cross sectional retrospective evaluation at one College of Pharmacy
Class of 2020 Abstract, Report and PosterSpecific Aims: To identify certain variables as predictors for overall NAPLEX passing scores for this University of Arizona College of Pharmacy Class of 2018 cohort. By the end of the study, associations between GPA, PCOA scores, and other factors should lead to a predictive tool for accessing a student's future success (or failure) on the NAPLEX.
Methods: Data was collected via University of Arizona College of Pharmacy admissions data along with release of MPJE and NAPLEX scores as well. The data was compiled together without demographic data to ensure anonymity of each participants' records.
Main Results: Stepwise logistic regression showed that the PCOA scaled score was a predictor for NAPLEX outcome, estimated parameter value: -0.0457 (p=0.0015). There was a significant difference in the pre-admissions cumulative GPA between the group passing the NAPLEX (mean GPA=3.61, SD=0.28) and the group that did not pass (mean GPA=3.30, SD=0.15) using a t-test statistic (p <.0001). The differences between PCOA (p <.0001) and composite PCAT scores (p=0.0286) also differed significantly between those who passed and those who failed the NAPLEX. Moderate, statistically significant correlations were found between NAPLEX scaled score with MPJE scaled score (r=0.59, p <.0001) and PCOA scaled score (r=0.51, p <.0001).
Conclusions: The PCOA test and pre-admissions GPA are good potential predictors for determining a student's outcome (pass or fail) on the NAPLEX test.This item is part of the Pharmacy Student Research Projects collection, made available by the College of Pharmacy and the University Libraries at the University of Arizona. For more information about items in this collection, please contact Jennifer Martin, Librarian and Clinical Instructor, Pharmacy Practice and Science, [email protected]
A Principle And Concept Perspective Of Conservation.
PhDTeacher educationUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/184657/2/6101817.pd
DNA Mismatch Repair Proteins and BRAF V600E Detection by Immunohistochemistry in Colorectal Cancer Demonstrates Concordance with Next Generation Sequencing
Background and Aims: Multiple laboratory methods are used to screen patients with colorectal cancer (CRC) for mismatch repair (MMR) protein deficiency to identify possible Lynch syndrome patients. The goal of this study was to compare the agreement between ready-to-use immunohistochemistry (IHC) assays for MLH-1, PMS-2, MSH-2, MSH-6, and mutated BRAF at V600E and molecular methods in CRC cases. The inclusion of the BRAF V600E mutation testing is important for the identification of patients with sporadic CRC, as the BRAF V600E mutation is very rarely observed in patients with Lynch syndrome tumors. Methods: CRC cases were analyzed by ColoSeqTM tumor sequencing assay and VENTANA MMR IHC Panel that included anti-MLH1, anti-PMS2, anti-MSH2, anti-MSH6, and anti-BRAF V600E antibodies. Additionally, CRC cases with MLH1 IHC loss were evaluated for MLH1 promoter hypermethylation. Results: One hundred and eighteen cases were analyzed. The overall percent agreement (OPA) for each evaluated marker status compared to next-generation sequencing (NGS) exceeded 96%. Twenty-three cases were positive for the BRAF V600E mutation by IHC and NGS, and twenty cases showed loss of MLH1 protein and were positive for MLH1 hypermethylation. Samples with loss of MMR protein expression by IHC demonstrated genetic and/or epigenetic alterations that were consistent with the observed protein expression patterns. Conclusions: The results of this study indicate that ready-to-use IHC assays can correctly identify the loss of MMR proteins and the presence of mutated BRAF V600E protein, supporting the utility of the VENTANA MMR IHC Panel as an aid to stratify patients with sporadic CRC vs. potential Lynch syndrome
A wildlife program for Saginaw Forest
Master of ScienceForestryUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/115766/1/39015003273995.pd
A story of conservation (for ten to fourteen year old children), supplemented by a guidebook for tea
Master of ScienceConservationUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/115767/1/39015003274019.pd
Recommended from our members
A summary of recent refinements to the WAKE dispersion model, a component of the HGSYSTEM/UF{sub 6} model suite
The original WAKE dispersion model a component of the HGSYSTEM/UF{sub 6} model suite, is based on Shell Research Ltd.`s HGSYSTEM Version 3.0 and was developed by the US Department of Energy for use in estimating downwind dispersion of materials due to accidental releases from gaseous diffusion plant (GDP) process buildings. The model is applicable to scenarios involving both ground-level and elevated releases into building wake cavities of non-reactive plumes that are either neutrally or positively buoyant. Over the 2-year period since its creation, the WAKE model has been used to perform consequence analyses for Safety Analysis Reports (SARs) associated with gaseous diffusion plants in Portsmouth (PORTS), Paducah (PGDP), and Oak Ridge. These applications have identified the need for additional model capabilities (such as the treatment of complex terrain and time-variant releases) not present in the original utilities which, in turn, has resulted in numerous modifications to these codes as well as the development of additional, stand-alone postprocessing utilities. Consequently, application of the model has become increasingly complex as the number of executable, input, and output files associated with a single model run has steadily grown. In response to these problems, a streamlined version of the WAKE model has been developed which integrates all calculations that are currently performed by the existing WAKE, and the various post-processing utilities. This report summarizes the efforts involved in developing this revised version of the WAKE model
Recommended from our members
Uncertainty analysis for low-level radioactive waste disposal performance assessment at Oak Ridge National Laboratory
A performance assessment of the operating Solid Waste Storage Area 6 (SWSA 6) facility for the disposal of low-level radioactive waste at the Oak Ridge National Laboratory has been prepared to provide the technical basis for demonstrating compliance with the performance objectives of DOE Order 5820.2A, Chapter 111.2 An analysis of the uncertainty incorporated into the assessment was performed which addressed the quantitative uncertainty in the data used by the models, the subjective uncertainty associated with the models used for assessing performance of the disposal facility and site, and the uncertainty in the models used for estimating dose and human exposure. The results of the uncertainty analysis were used to interpret results and to formulate conclusions about the performance assessment. This paper discusses the approach taken in analyzing the uncertainty in the performance assessment and the role of uncertainty in performance assessment