The analysis of structurally orthotropic shells by means of the compliance method Progress report, period ending 1 Jun. 1968

Linear shell theory elastic constant instability conditions for symmetrically loaded shells of revolutio

The analysis of structurally orthotropic shells by means of the compliance method

Structurally orthotropic shells analyzed by compliance metho

Foundations of linear inelastic shell theory progress report

Foundations of linear inelastic thin shell theor

Investigation of fatigue strength of multilayer advanced fiber composites

The analytical characterization of a multilayer fiber composite plate (without hole) was accomplished for both static and dynamic loading conditions using the finite difference technique. Thornel 300/5208 composites with and without holes were subjected to static and tensile fatigue testing. Five (5) fiber orientations were submitted to test. Tensile fatigue testing also included three (3) loading conditions and two (2) frequencies. The low-cycle test specimens demonstrated a shorter tensile fatigue life than the high-cycle test specimens. Failure surfaces demonstrated effect of testing conditions. Secondary failure mechanisms, such as: delamination, fiber breakage, and edge fiber delamination were present. Longitudinal delamination between plies also occurred in these specimens

Identification of Kelvin waves: numerical challenges

Kelvin waves are expected to play an essential role in the energy dissipation for quantized vortices. However, the identification of these helical distortions is not straightforward, especially in case of vortex tangle. Here we review several numerical methods that have been used to identify Kelvin waves within the vortex filament model. We test their validity using several examples and estimate whether these methods are accurate enough to verify the correct Kelvin spectrum. We also illustrate how the correlation dimension is related to different Kelvin spectra and remind that the 3D energy spectrum E(k) takes the form 1/k in the high-k region, even in the presence of Kelvin waves.Comment: 6 pages, 5 figures. The final publication is available at http://www.springerlink.co

Meaningfulness of academic migrants’ education, its assessment and modeling on IT-based technologies

The article is devoted to the relevant problems of educational migration flows both in the real and virtual environment. The article discusses the positive and negative experience with virtual platforms in Russia and abroad. Particular attention is paid to the cultural and cognitive characteristics of the students belonging to the Generation Z, which requires the creation of entirely different instruments for implementing the educational process. The authors propose the method of creation, control and evaluation of feedback in the process of virtual educational migration using the latest IT-technologies that are utilized to create ultra-fast feedback and allow to bring new technologies into the learning process. In this scheme, the student is no longer a passive listener, but an active creator of new knowledge. The methodical research toolkit includes the mathematical, engineering, information methods of processing the results, including computer simulation. The testing of methodological tools was held at the University of Economics in Bratislava (Slovakia). These results confirm the possibility of the new method of providing feedback.This enable to improve the training quality of students, who are the members of the educational migration flows. Moreover, the training and examining may start at courses on adaptation, enabling to pre-determine the necessary competencies. In addition, it is cost-effective to limit the real presence of foreign lecturers at the host university to a certain minimum, followed by the support for virtual feedback. However, the use of IT-technologies is not a sufficient factor in improving the quality of education and the level of progress achieved by the trainees, but it can be a good helper in the course of the examination, automation of the selected methods of control, as it is a more individualized approach to learning

System Response Kernel Calculation for List-mode Reconstruction in Strip PET Detector

Reconstruction of the image in Positron Emission Tomographs (PET) requires the knowledge of the system response kernel which describes the contribution of each pixel (voxel) to each tube of response (TOR). This is especially important in list-mode reconstruction systems, where an efficient analytical approximation of such function is required. In this contribution, we present a derivation of the system response kernel for a novel 2D strip PET.Comment: 10 pages, 2 figures; Presented at Symposium on applied nuclear physics and innovative technologies, Cracow, 03-06 June 201

A novel method for calibration and monitoring of time synchronization of TOF-PET scanners by means of cosmic rays

All of the present methods for calibration and monitoring of TOF-PET scanner detectors utilize radioactive isotopes such as e.g. $^{22}$Na or $^{68}$Ge, which are placed or rotate inside the scanner. In this article we describe a novel method based on the cosmic rays application to the PET calibration and monitoring methods. The concept allows to overcome many of the drawbacks of the present methods and it is well suited for newly developed TOF-PET scanners with a large longitudinal field of view. The method enables also monitoring of the quality of the scintillator materials and in general allows for the continuous quality assurance of the PET detector performance.Comment: 10 pages, 7 figure