Substructure analysis using NICE/SPAR and applications of force to linear and nonlinear structures

Parallel computing studies are presented for a variety of structural analysis problems. Included are the substructure planar analysis of rectangular panels with and without a hole, the static analysis of space mast, using NICE/SPAR and FORCE, and substructure analysis of plane rigid-jointed frames using FORCE. The computations are carried out on the Flex/32 MultiComputer using one to eighteen processors. The NICE/SPAR runstream samples are documented for the panel problem. For the substructure analysis of plane frames, a computer program is developed to demonstrate the effectiveness of a substructuring technique when FORCE is enforced. Ongoing research activities for an elasto-plastic stability analysis problem using FORCE, and stability analysis of the focus problem using NICE/SPAR are briefly summarized. Speedup curves for the panel, the mast, and the frame problems provide a basic understanding of the effectiveness of parallel computing procedures utilized or developed, within the domain of the parameters considered. Although the speedup curves obtained exhibit various levels of computational efficiency, they clearly demonstrate the excellent promise which parallel computing holds for the structural analysis problem. Source code is given for the elasto-plastic stability problem and the FORCE program

A Java image editor and enhancer

The purpose of this project is to develop a Java Applet that provides all the tools needed for creating image fantasies. It lets the user pick a template and an image, and combine them together. The user can then apply image processing techniques such as rotation, zooming, blurring etc according to his/her requirements

Nonproportionally Loaded Steel Beam-Columns and Flexibly-Connected Nonsway Frames

A theoretical study of the inelastic stability of nonproportionally loaded steel beam-columns and flexibly-connected frames is conducted. Specifically, solution techniques are formulated to predict the nonlinear behavior of cross sections, spatial beam-columns, and nonsway plane frames under the combined influence of imperfections, flexible connections, and nonproportional loads. A set of new inelastic slope-deflection equations for imperfect members are derived and their use illustrated through in-depth studies of flexibly-connected portal and two-bay two-story frames. These equations are derived from a system of nonlinear ordinary differential equations. The member studies are carried out using a second-order finite-difference solution to a set of nonlinear equilibrium equations, and coupled to a tangent stiffness procedure for cross sections. The majority of the theoretical studies are carried out on a conventional sequential computer. Efficient concurrent computational algorithms are also presented for biaxial bending and column stability problems. Results are obtained using a multiprocessor computer known as the Finite Element Machine. A critical appraisal of the conventional tangent modulus approach is presented in light of the analysis which includes elastic unloading of the material. It is found that the tangent modulus approach results in a fictitious ductile behavior. Furthermore, is is also realized that there is a dramatic difference in the nonlinear behavior between the proportionally and nonproportionally loaded structures. It is also observed that the proportionally loaded structures lead to rather unconservative peak loads. Additionally, members as integral parts of a frame may exhibit significantly different load-deformation behavior as compared to that of isolated members. The study on members and frames shows that nonproportional loads have a significant effect on their behavior and strength

Two-dimensional finite element analysis of rectangular panel with hole using NICE/SPAR

A panel 30 in. long, 11.5 in. wide, with a 2.0 in. diameter hole at the center is analyzed. Since a two-dimensional analysis is conducted, the thickness of the panel is taken as unity. Owing to the symmetry, it is sufficient to analyze only one fourth of the panel with appropriate boundary conditions

Aneurysmal Subarachnoid Hemorrhage in Pregnancy-Case Series, Review, and Pooled Data Analysis.

BACKGROUND: Aneurysmal subarachnoid hemorrhage (aSAH) during pregnancy represents an important cause of maternal and fetal morbidity and mortality. Approaches to diagnostics and treatment are still controversial, and there are only a limited number of cases described in the literature. Our study examines the management of aSAH in pregnant patients, creating a case series by combining patients from our hospital records with those from the limited available literature. METHODS: Data collected from Addenbrooke's Hospital records and cases published between January 1995 and January 2015 were studied. Chi-square test, exact Fisher's test, and chi-square test for trend were used for analyzing categorical data, while the t-test and Mann-Whitney-Wilcoxon test were used for continuous data. RESULTS: Fifty-two patients were included. The mean age was 31.47 ± 5.80, and most patients were in their third trimester. A univariate pooled data analysis suggested that the maternal outcome may depend on the mother's age, mother's Hunt and Hess scale score, Glasgow Coma Scale at arrival, treatment modality for the aneurysm, mode, and timing of delivery. However, at the multivariate analysis only the presence of general complications resulted in a significant impact on maternal outcome. CONCLUSIONS: Ruptured aneurysms in pregnant patients with aSAH may be safely secured in a timely manner. The diagnostic and treatment strategy for each of these patients should consider peculiar maternal and obstetric factors and requires a multidisciplinary assessment involving obstetrics, neurosurgeons, and intensivists. Considering the observed statistical power of our series, our findings should be taken with caution and should be supported by further systematic data collection.This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.wneu.2015.12.02

A computational framework for flow-induced vibrations of propeller blades in cavitating flows

In the current work, we present a finite-element computational framework for Fluid-Structure Interaction problems subjected to the coupling of unsteady cavitating flows with flexible structures. We build upon a previously developed stabilized variational framework for multiphase FSI by incorporating a dynamical structural solver based on the modal decomposition of the structure. In the first part of the work, we present the validation of the current framework for conducting Large Eddy Simulations (LES) of cavitating flows past rigid structures. We identify the resolution criteria for dynamic subgrid-scale LES based on the re-entrant jet momentum - a prominent phe- nomenon associated with cavity-shedding in the wake of immersed bodies. The validated framework is then used to elucidate the features of cavitating flow past a rigid hydrofoil. In particular, we iden- tify features of sheet-cavitating flow which enable the transition to cloud cavitation. Further, we evaluate the instabilities driving sheet-cavity breakdown and establish the vortical structures which drive cloud cavity collapse, and quantify the frequencies observed over the course of a cavitation cycle. In the second part of the work, we present the validation of the framework for LES of cavitating flows past flexible structures. Based on the validation study conducted over a flexible NACA66 rectangular hydrofoil, we elucidate the role of cavity and vortex shedding in the structural dynamics at three different cavitation numbers. We identify a broad spectrum frequency band whose central peak does not correlate to the frequency content of the cavitation dynamics or the natural fre- quencies of the structure, indicating the induction of unsteady flow patterns around the hydrofoil. Finally, we discuss the coupled fluid-structure dynamics during a cavitation cycle associated with the promotion and mitigation of cavitation.Applied Science, Faculty ofMechanical Engineering, Department ofGraduat

Synthesis, characterization and biological activities of substituted cinnoline culphonamides

Background: The Cinnoline moiety and Sulphonamide moiety both have good antimicrobial properties. Methods: In the present study both the moieties were condensed to synthesize substituted cinnoline sulphonamide derivatives using intramolecular cyclization followed by diazotization in order to get synergistic activity. Results: These derivatives particularly halogen substituted cinnoline derivatives showed potent antimicrobial activity. Conclusion: Further investigations are required to find out possible mechanism of action

Synthesis, characterization and biological activities of substituted cinnoline culphonamides

Background: The Cinnoline moiety and Sulphonamide moiety both have good antimicrobial properties. Methods: In the present study both the moieties were condensed to synthesize substituted cinnoline sulphonamide derivatives using intramolecular cyclization followed by diazotization in order to get synergistic activity. Results: These derivatives particularly halogen substituted cinnoline derivatives showed potent antimicrobial activity. Conclusion: Further investigations are required to find out possible mechanism of action.Keywords: Cinnoline, Antibacterial, Antifungal