A three-dimensional turbulent compressible flow model for ejector and fluted mixers

A three dimensional finite element computer code was developed to analyze ejector and axisymmetric fluted mixer systems whose flow fields are not significantly influenced by streamwise diffusion effects. A two equation turbulence model was used to make comparisons between theory and data for various flow fields which are components of the ejector system, i.e., (1) turbulent boundary layer in a duct; (2) rectangular nozzle (free jet); (3) axisymmetric nozzle (free jet); (4) hypermixing nozzle (free jet); and (5) plane wall jet. Likewise, comparisons of the code with analytical results and/or other numerical solutions were made for components of the axisymmetric fluted mixer system. These included: (1) developing pipe flow; (2) developing flow in an annular pipe; (3) developing flow in an axisymmetric pipe with conical center body and no fluting and (4) developing fluted pipe flow. Finally, two demonstration cases are presented which show the code's ability to analyze both the ejector and axisymmetric fluted mixers

Information Systems Development Success: Perspective of Software Development Team Members

The traditional models of IS success measure success from the viewpoint of the system, users, and the organization. The system viewpoint is measured by information quality, system quality, and service quality; the users’ viewpoint by user satisfaction, use, and individual net benefits; and the organization’s viewpoint by organizational net benefits. This study adds the development team’s viewpoint. I decompose system quality into its functional and nonfunctional components and combine them with new constructs to create Information System Development (ISD) success. Like IS Success, ISD Success is a comprehensive model composed of multiple interrelated dimensions: practitioner satisfaction, project manager satisfaction, and the antecedents to these constructs, which include functional system quality, non-functional system quality, and process quality. Unlike the traditional models of IS success, ISD Success can be used to evaluate systems during the development cycle as well as on projects that never reach completion or are never used

Modeling of three-dimensional mixing and reacting ducted flows

A computer code, based upon a finite element solution algorithm, was developed to solve the governing equations for three-dimensional, reacting boundary region, and constant area ducted flow fields. Effective diffusion coefficients are employed to allow analyses of turbulent, transitional or laminar flows. The code was used to investigate mixing and reacting hydrogen jets injected from multiple orifices, transverse and parallel to a supersonic air stream. Computational results provide a three-dimensional description of velocity, temperature, and species-concentration fields downstream of injection. Experimental data for eight cases covering different injection conditions and geometries were modeled using mixing length theory (MLT). These results were used as a baseline for examining the relative merits of other mixing models. Calculations were made using a two-equation turbulence model (k+d) and comparisons were made between experiment and mixing length theory predictions. The k+d model shows only a slight improvement in predictive capability over MLT. Results of an examination of the effect of tensorial transport coefficients on mass and momentum field distribution are also presented. Solutions demonstrating the ability of the code to model ducted flows and parallel strut injection are presented and discussed

Operating system efficiency evaluation on the base of measurements analysis with the use of non-extensive statistics elements

The major goal of this article was to evaluate the efficiency of Linux operating systemusing statistical self-similarity and multifractal analysis. In order to collect the necessary data, thetools available in Linux such as vmstat, top and iostat were used. The measurement data collected withthose tools had to be converted into a format acceptable by applications which analyze statistical selfsimilarityand multifractal spectra. Measurements collected while using the MySQL database systemin a host operating system were therefore analyzed with the use of statistical self-similarity and allowedto determine the occurrence of long-range dependencies. Those dependencies were analyzed with theuse of adequately graduated diagrams. Multifractal analysis was conducted with the help of FracLabapplication. Two methods were applied to determine the multifractal spectra. The obtained spectrawere analyzed in order to establish the multifractal dependencies

Team Members\u27 Perspectives on Information Systems Development Success

Many information systems development (ISD) projects are deemed a failure in the field. However, several practitioners and researchers argue these projects could actually be considered successful if we used a broader definition of software development project success. Answering the call for further research on what makes ISD projects successful, this paper describes the process used to build the theoretical model of ISD Success, which includes a thorough literature review to create an initial model followed by semi-structured interviews conducted to validate the model and to allow for the discovery of emergent constructs, sub-constructs, and hypotheses. The end result of this research is the theoretical model of ISD success. After subsequent research has established the links from ISD success to IS success, project professionals will be able to use the ISD Success to predict success of an ISD project. Early prediction may allow professionals to head off potentially unsuccessful systems

Depressive symptoms in schizophrenic patients

Distinction between true negative and depressive symptoms in schizophrenia is difficult. In the present study we seek to establish the psychological profile of depression-prone schizophrenic patients. We addressed the issue by comparing the expression of psychological indices, such as the feelings of being in control of events, anxiety, mood, and the style of coping with stress in depressive and non-depressive schizophrenics. We also analyzed the strength of the association of these indices with the presence of depressive symptoms. A total of 49 patients (18 women and 31 men, aged 23-59) were enrolled into the study, consisting of a self-reported psychometric survey. We found that the prevalence of clinically significant depression in schizophrenic patients was 61%. The factors which contributed to the intensification of depressive symptoms were the external locus of control, anxiety, gloomy mood, and the emotion-oriented coping with stress. We conclude that psychological testing may discern those schizophrenic patients who would be at risk of depression development and may help separate the blurred boundaries between depressive and negative symptoms of schizophrenia