1,397 research outputs found
Three-dimensional free vibration analysis of thermally loaded fgm sandwich plates
Using the finite element code ABAQUS and the user-defined material utilities UMAT and UMATHT, a solid brick graded finite element is developed for three-dimensional (3D) modeling of free vibrations of thermally loaded functionally gradient material (FGM) sandwich plates. The mechanical and thermal material properties of the FGM sandwich plates are assumed to vary gradually in the thickness direction, according to a power-law fraction distribution. Benchmark problems are firstly considered to assess the performance and accuracy of the proposed 3D graded finite element. Comparisons with the reference solutions revealed high efficiency and good capabilities of the developed element for the 3D simulations of thermomechanical and vibration responses of FGM sandwich plates. Some parametric studies are carried out for the frequency analysis by varying the volume fraction profile and the temperature distribution across the plate thickness
Two-Body Density Matrix for Closed s-d Shell Nuclei
The two-body density matrix for and within the
Low-order approximation of the Jastrow correlation method is considered. Closed
analytical expressions for the two-body density matrix, the center of mass and
relative local densities and momentum distributions are presented. The effects
of the short-range correlations on the two-body nuclear characteristics are
investigated.Comment: 13 pages(LaTeX), 4 figures (ps
MAP: Microblogging Assisted Profiling of TV Shows
Online microblogging services that have been increasingly used by people to
share and exchange information, have emerged as a promising way to profiling
multimedia contents, in a sense to provide users a socialized abstraction and
understanding of these contents. In this paper, we propose a microblogging
profiling framework, to provide a social demonstration of TV shows. Challenges
for this study lie in two folds: First, TV shows are generally offline, i.e.,
most of them are not originally from the Internet, and we need to create a
connection between these TV shows with online microblogging services; Second,
contents in a microblogging service are extremely noisy for video profiling,
and we need to strategically retrieve the most related information for the TV
show profiling.To address these challenges, we propose a MAP, a
microblogging-assisted profiling framework, with contributions as follows: i)
We propose a joint user and content retrieval scheme, which uses information
about both actors and topics of a TV show to retrieve related microblogs; ii)
We propose a social-aware profiling strategy, which profiles a video according
to not only its content, but also the social relationship of its microblogging
users and its propagation in the social network; iii) We present some
interesting analysis, based on our framework to profile real-world TV shows
Advances in surface EMG signal simulation with analytical and numerical descriptions of the volume conductor
Surface electromyographic (EMG) signal modeling is important for signal interpretation, testing of processing algorithms, detection system design, and didactic purposes. Various surface EMG signal models have been proposed in the literature. In this study we focus on 1) the proposal of a method for modeling surface EMG signals by either analytical or numerical descriptions of the volume conductor for space-invariant systems, and 2) the development of advanced models of the volume conductor by numerical approaches, accurately describing not only the volume conductor geometry, as mainly done in the past, but also the conductivity tensor of the muscle tissue. For volume conductors that are space-invariant in the direction of source propagation, the surface potentials generated by any source can be computed by one-dimensional convolutions, once the volume conductor transfer function is derived (analytically or numerically). Conversely, more complex volume conductors require a complete numerical approach. In a numerical approach, the conductivity tensor of the muscle tissue should be matched with the fiber orientation. In some cases (e.g., multi-pinnate muscles) accurate description of the conductivity tensor may be very complex. A method for relating the conductivity tensor of the muscle tissue, to be used in a numerical approach, to the curve describing the muscle fibers is presented and applied to representatively investigate a bi-pinnate muscle with rectilinear and curvilinear fibers. The study thus propose an approach for surface EMG signal simulation in space invariant systems as well as new models of the volume conductor using numerical methods
Clinical Case of a Child with Optic Neuritis, Associated with Epstein-Barr Virus
We present a clinical case of a child with bilateral papillitis, associated with EBV-infection in a 5-year-old female child, who was diagnosed and treated at the Aleksandrovska University Hospital. The initial reason for the eye-exam was a new-onset squint. On admission, she had discrete Eidon confocal scan, decreased visual acuity and bilateral edema and hyperemia of the optic disks. MRI of brain and orbits was evaluated on emergency to rule out a demyelinating or intracranial process. The child had persistent lymphadenopathy and laboratory abnormalities and tested positive for EBV serology. She was treated with intravenous corticosteroid pulse therapy and visual acuity was restored to 100%. Papillitis in children is frequently bilateral, with viral genesis and has a good prognosis. Isolated papillitis (without inflammation of other eye structures) is difficult to distinguish clinically from papilledema. When papilledema is suspected, urgent MRI has to be carried out
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