Accelerated convergence for incompressible flow calculations

Two improved algorithms which solve the steady-state Navier-Stokes equations, PISO and SIMPLER, are studied. Computations were carried out on progressively finer grids for the driven cavity and flow over a backward-facing step. The effects of relaxation factor, number of grid nodes and number of sweeps through the pressure equations are studied to evaluate the performance of the PISO and SIMPLER schemes. Results show that these improved schemes accelerate the convergence rate of the solution generally by a factor of two as compared to the SIMPLE method

Mesoscopic dynamical differences from quantum state preparation in a Bose-Hubbard trimer

Conventional wisdom is that quantum effects will tend to disappear as the number of quanta in a system increases, and the evolution of a system will become closer to that described by mean field classical equations. In this letter we combine newly developed experimental techniques to propose and analyse an experiment using a Bose-Hubbard trimer where the opposite is the case. We find that differences in the preparation of a centrally evacuated trimer can lead to readily observable differences in the subsequent dynamics which increase with system size. Importantly, these differences can be detected by the simple measurements of atomic number.Comment: 5 pages, 4 figures, theor

Flame radiation and liner heat transfer in a tubular-can combustor

Heat transfer within a combuster were examined. Total and spectral flame radiation in a tubular can combustor at a series of parametric operating conditions was measured. Radiation measurements were taken for a range of inlet air pressures from 0.34 to 2.0 MPa, inlet air temperatures from 533 to 700 K, with two different fuels, Jet-A and ERBS. Measurements of liner temperatures combined with the parametric radiation results allowed a calculation of the combustor liner heat loads. Flame emissivity was determined from the spectral measurements

A case based approach to teaching spreadsheet and database applications

Although most schools offer and/or require a course in spreadsheet and database applications, the amount of meaningful learning derived from the class varies widely. The approach described in this paper involves a combination for demonstration and hands-on practice using two term-long cases to be used in an introductory course in spreadsheet and database applications. These cases, packaged together with slides emphasizing theory, hands-on quizzes and exams that foster critical thinking, can be used across the multiple sections that are taught to maintain consistency within the course and encourage faculty and students to take the course to a higher level. Evidence based on final exam scores indicates that students are achieving the higher level of understanding that is the intent of this method of teaching

Mastery level learning and the art of database design

Database design is as much an art as it is a science. In order for students to become skilled enough to produce an effective design, they will need to achieve the synthesis level of Bloom\u27s taxonomy. Given the effort involved in reaching that level, a constructivist approach may not be sufficient. Based on learning styles research, it can be shown that learners with a mastery level coping style will be more likely to stick with the process long enough to achieve the synthesis level than will learners with a helpless learning style. The process described in this paper incorporates many standard database teaching techniques, along with an innovative example and various pedagogical techniques to help the student adopt a mastery level mindset and achieve the necessary level of cognitive skill to effectively design databases

Reaction development and mechanistic investigation of rhodium-catalyzed pyridine synthesis via C-H activation

2014 Fall.Includes bibliographical references.Described herein are two complementary rhodium-catalyzed methods for the synthesis of substituted pyridines from unsaturated oxime derivatives and alkenes. In the first, formal [4+2] cycloaddition of O-pivaloyl α, β-unsaturated oxime esters and activated terminal alkenes was discovered to proceed in high yields and with excellent selectivity for 6-substituted pyridine products. Mechanistic experiments were found to be consistent with a reversible C-H activation step and a C-N bond forming, N-O bond cleaving process en route to pyridine formation. Rhodium-catalyzed coupling using unactivated alkene substrates was shown to present important information regarding the influence of the alkene component on product distribution. In a second method, access to 5-substituted pyridine derivatives was achieved by decarboxylative annulation of α, β-unsaturated oxime esters and β-substituted acrylic acid derivatives. In this case, carboxylic acids were found to serve as traceless activating groups for selective alkene incorporation. A wealth of mechanistic insight was gained by identification of and decomposition studies regarding catalytically relevant rhodium complexes

Data quality and the data warehouse: A Decision support system for allocation of scarce resources

This paper describes a decision support system (DSS) for use in allocating scarce resources associated with data quality efforts in the construction of a data warehouse. The DSS is populated with metadata from a data warehouse project, including tags that identify the quality at intersections of data field, data use, and data dimensions. The resulting DSS can then experiment using business students are then presented. It can be shown that, given the proper set of skills, business students, as proxies for novices on a data warehouse development team, can effectively use the tool to analyze and prioritize hundreds of potential fields in a data warehouse project

Data quality knowledge management: A Tool for the collection and organization of metadata in a data warehouse

This paper describes a relational database tool, the Data Quality Knowledge Management (DQKM), which captures and organizes the metadata associated with a data warehouse project. It builds on the concept of fitness for use by describing a measurement technique for subjectively assigning a measure to a data field based on the use and quality dimension of the dat within the data warehouse. This measurement can then be compared to some minimum criteria, below which it is not cost effective to enhance the quality of the data. This tool can be use to make resource allocation decisions and get the greatest benefit for the cost in utilizing the scarce resources available to enhance source data for a data warehouse

The Product approach to data quality and fitness for use: A Framework for analysis

The value of management decisions, the security of our nation, and the very foundations of our business integrity are all dependent on the quality of data and information. However, the quality of the data and information is dependent on how that data or information will be used. This paper proposes a theory of data quality based on the five principles defined by J. M. Juran for product and service quality and extends Wang et al\u27s 1995 framework for data quality research. It then examines the data and information quality literature from journals within the context of this framework