Analysis of polyhedral domed sandwich structures

The finite element method was employed for the analysis of the polyhedral domed sandwich structures. Two different variational approaches were used for comparison reasons. These are the "displacement formulation" and the "mixed formulation" as they are commonly known. Initially seven sandwich plate bending models were developed. These models were used to solve a number of problems where a numerical or experimental solution existed and comparisons were made. The agreement varied from fair to excellent depending on the nature of the model and the type of the solved problem. As a result of this comparative study four of these models were consequently selected to be extended for the development of the sandwich dome models. The accuracy of these four sandwich dome models was tested by modelling five polyhedral dome structures. The results derived from each individual model were compared with experimental results obtained by other researchers and by the author himself. The author's contribution to the experimental work was the design, construction and subsequent testing of two full scale prototypes, namely, the 24 faced and the 36-faced domes. From the whole analysis it was established that the developed numerical models, when selectively applied in the most appropriate way with regard to their special characteristics and the nature of the problem, produce reliable results. Special problems were investigated arising from the boundary conditions as well as structural details! of the joint-lines. of the plates forming the polyhedron, and thus a solution was suggested. Finally, a data generation routine is also described in order to facilitate further application of the various developed models by future users or researchers

Alien Registration- Manos, Louis C. (Sanford, York County)

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High Intensity Interval Training or Moderate Intensity Continuous Exercise in Patients with Myocardial Infarction?

Objectives: To determine the effects of high intensity interval training (HIIT) or moderate intensity continuous exercise (MICE) in patients with myocardial infarction (MI). Background: Cardiovascular diseases are the leading cause of mortality and morbidity globally causing a significant reduction in the quality of life of these patients. Participation of these patients in rehabilitation programs which involve a significant component of exercise seems to help by improving functional capacity and quality of life (QoL). Despite the beneficial effect of exercise, the type of exercise that yields the best results is yet to be determined.Methods: Three databases (MEDLINE, CINHAL and SportDirect) were searched in May-June 2017 for original articles regarding the effect of two types of exercise in patients with myocardial infarction. Randomized control trial studies which enrolled patients with myocardial infarction and studied the effects of HIIT and/or MICE, were included in this review. Data were extracted and summarised and all studies were assessed for bias.Results: Both forms of exercise seem to improve the relevant outcome measures such as functional capacity, QoL, walking distance, fatigue and function of the left heart. However HIIT seemed to be better in comparison with MICE in improving these outcomes. Several limitations and risk of bias have been identified and reported.Conclusion: Both HIIT and MICE are recommended for patients with MI. Further research is required to conclusively support the superiority of HIIT over other types of exercise

Conformal Magnetic Composite RFID for Wearable RF and Bio-Monitoring Applications

©2008 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or distribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.10.1109/TMTT.2008.2006810This paper introduces for the first time a novel flexible magnetic composite material for RF identification (RFID) and wearable RF antennas. First, one conformal RFID tag working at 480 MHz is designed and fabricated as a benchmarking prototype and the miniaturization concept is verified. Then, the impact of the material is thoroughly investigated using a hybrid method involving electromagnetic and statistical tools. Two separate statistical experiments are performed, one for the analysis of the impact of the relative permittivity and permeability of the proposed material and the other for the evaluation of the impact of the dielectric and magnetic loss on the antenna performance. Finally, the effect of the bending of the antenna is investigated, both on the S-parameters and on the radiation pattern. The successful implementation of the flexible magnetic composite material enables the significant miniaturization of RF passives and antennas in UHF frequency bands, especially when conformal modules that can be easily fine-tuned are required in critical biomedical and pharmaceutical applications

Interplay Between Chaotic and Regular Motion in a Time-Dependent Barred Galaxy Model

We study the distinction and quantification of chaotic and regular motion in a time-dependent Hamiltonian barred galaxy model. Recently, a strong correlation was found between the strength of the bar and the presence of chaotic motion in this system, as models with relatively strong bars were shown to exhibit stronger chaotic behavior compared to those having a weaker bar component. Here, we attempt to further explore this connection by studying the interplay between chaotic and regular behavior of star orbits when the parameters of the model evolve in time. This happens for example when one introduces linear time dependence in the mass parameters of the model to mimic, in some general sense, the effect of self-consistent interactions of the actual N-body problem. We thus observe, in this simple time-dependent model also, that the increase of the bar's mass leads to an increase of the system's chaoticity. We propose a new way of using the Generalized Alignment Index (GALI) method as a reliable criterion to estimate the relative fraction of chaotic vs. regular orbits in such time-dependent potentials, which proves to be much more efficient than the computation of Lyapunov exponents. In particular, GALI is able to capture subtle changes in the nature of an orbit (or ensemble of orbits) even for relatively small time intervals, which makes it ideal for detecting dynamical transitions in time-dependent systems.Comment: 21 pages, 9 figures (minor typos fixed) to appear in J. Phys. A: Math. Theo

The Structural Performance of Stone-Masonry Bridges

The structural performance of old stone-masonry bridges is examined by studying such structures located at the North-West of Greece, declared cultural heritage structures. A discussion of their structural system is included, which is linked with specific construction details. The dynamic characteristics of four stone bridges, obtained by temporary in situ instrumentation, are presented together with the mechanical properties of their masonry constituents. The basic assumptions of relatively simple three-dimensional (3-D) numerical simulations of the dynamic response of such old stone bridges are discussed based on all selected information. The results of these numerical simulations are presented and compared with the measured response obtained from the in situ experimental campaigns. The seismic response of one such bridge is studied subsequently in some detail as predicted from the linear numerical simulations under combined dead load and seismic action. The performance of the same bridge is also examined applying 3-D non-linear numerical simulations with the results used to discuss the structural performance of stone-masonry bridges that either collapsed or may be vulnerable to future structural failure. Issues that influence the structural integrity of such bridges are discussed combined with the results of the numerical and in situ investigation. Finally, a brief discussion of maintenance issues is also presented