1,239 research outputs found
Mathematics Intelligent Tutoring System
In these days, there is an increasing technological development in intelligent tutoring systems. This field has become interesting to many researchers. In this paper, we present an intelligent tutoring system for teaching mathematics that help students understand the basics of math and that helps a lot of students of all ages to understand the topic because it's important for students of adding and subtracting. Through which the student will be able to study the course and solve related problems. An evaluation of the intelligent tutoring systems was carried out and the results were encouraging
Pancreatic pseudocyst eroding into the splenoportal venous confluence and mimicking an arterial aneurysm
We report the case of a 62-year-old man with chronic pancreatitis who presented with increasing abdominal pain. Sonography, magnetic resonance imaging, contrast-enhanced computed tomography, and ultimately catheter angiography demonstrated a pancreatic pseudocyst that had eroded into the splenoportal venous confluence, mimicking an arterial aneurysm. The diagnostic was confirmed at the time of surgical treatment. This case demonstrates the use of imaging to diagnose complications of pancreatitis, and the difficulty of distinguishing an eroding pseudocyst from an arterial aneurysm
Dielectric Relaxation of Some Large Aromatic Molecules in Benzene from Microwave Absorption Measurements
The Dispersion Relation of Flexural Waves in a Magnetoelastic Anisotropic Circular Cylinder
The objective of this paper is to investigate some aspects of dispersion relation of flexural waves propagation in a transversely isotropic hollow circular cylinder of infinite extent placed in a primary magnetic field. A frequency equation appropriate to the hollow circular cylinder is obtained by using the lame (Helmholtz) potentials for arbitrary values of the physical parameters involve as well as the primary magnetic field. Numerical calculations have been carried out when the cylinder is made of the material of Zinc Oxide. This study shows that waves in a solid body propagating under the influence of a superimposed magnetic field can differ significantly from those propagating in the absence of the magnetic field. Also, one may see that the effect of the primary magnetic field is to increase the values of the materials constants. Finally the results are given for different values of the primary magnetic field and presented graphically. The standard results of the previous investigations have also been deduced as particular cases. Keywords: Natural frequencies, Magnetoelasticity, Flexural wave, transversely isotropic material
Biomimetic Potentials for Building Envelope Adaptation in Egypt
AbstractBiomimicry is a science that seeks sustainable solutions by emulating nature's time-tested 3.8 billion years of patterns and strategies. The paper is concerned with embodying the biomimetic strategies to building envelopes which shall offer a high potential to reduce the energy demand, save material and thus improve the sustainability of buildings, through accessing current practices process of natural ventilation biomimicry in buildings for a potential application in building envelope for environmental adaptation which could help for the emergence of a new generation of biomimetic building envelopes aiming at promoting biomimicry in Egypt by showing the benefits that could be harvested
On the Extensional and Flexural of Generalized Thermoelastic Waves in an Anisotropic Plate
The propagation of extensional and flexural motions of generalized thermoelastic waves in a homogeneous, transversely isotropic plate of finite width is considered. The frequency equations for the plates in closed form and suitable mathematical conditions for symmetric and antisymmetric wave modes propagation are derived. Numerical calculations for three various theories of generalized thermoelasticity is carried out. In each case the real and imaginary parts of the frequency equation as a function of phase velocity for different values of thermal relaxation times are illustrated graphically. It is found that, the frequency equations of the extensional and flexural motions can be oscillate with respect to the medial of the plate. Moreover, it gets modified due to the thermal relaxation times and anisotropic effects. Finally, the results for the coupled thermoelasticity can be obtained as particular cases of the results by setting thermal relaxation times equal to zero Keywords: Frequency equations; Extensional and flexural modes; Thermal relaxation times; Harmonic wave propagatio
Natural Frequencies of Magnetoelastic Longitudinal Wave Propagation in an Orthotropic Circular Cylinder
In this paper, we study the longitudinal wave propagation in a perfectly conducting elastic circular cylinder in the presence of an axial initial magnetic field. The elastic cylinder is assumed to be made of an orthotropic material. The problem is represented by the equations of elasticity taking into account of the effect of the magnetic field as given by Maxwell's equations in the quasi-static approximation. The stress free conditions on the inner and outer surfaces of the hollow circular cylinder are used to form a frequency equation in terms of the wavelength, the cylinder radii and the material constants. Numerical calculations are obtained and the results are represented graphically. It is observed that the longitudinal elastic waves in a solid body propagating under the influence of a superimposed magnetic field can be different significantly from that of those propagating in the absence of a magnetic field. Also, elastic waves may convey information on electromagnetic properties of the material: for example through a precise measurement of the surface current induced by the presence of the magnetic field. Finally, some of the earlier results are deduced as particular cases. Keywords: Natural frequencies, Magnetoelasticity, Longitudinal wave, Orthotropic materials
Numerical Computations of Radial Vibrations of Axially Polarized Piezoelectric Circular Cylinder
Influence of the initial stresses on the frequency equation and the natural frequencies for radial vibrations of axially polarized piezoelectric circular cylinder have been taken into account. The mechanical boundary conditions correspond to those of stress free lateral surfaces while the electrical boundary conditions correspond to those of open and short circuit are considered. The satisfaction of the boundary conditions lead to the frequency equation, in the form of determinant involving Bessel functions, have been taken into consideration. The roots of the frequency equations give the values of the characteristic circular frequency parameters of the first three modes for various geometries. These roots are numerically computed and programmed for numerical evaluation by ''Bisection Method Iterations Technique (BMIT)'' and presented graphically for various thickness of the circular cylinder and for different values of the initial stress. The effect of the initial stress on the natural frequencies are illustrated graphically for a transversely isotropic piezoelectric martial PZT?4 circular cylinder. It is found that both the thickness of the circular cylinder and the initial stress have a substantial effect on the dispersion behavior. The results obtained in this paper may be applied to the vibrations of annular accelerometers operating in the radial shear mode. Also, they have theoretical basis application and have meaningful design for piezoelectric probes and electro-acoustic devices in the nondestructive evaluation. Keywords: Piezoelectricity, frequency equation, Transverse surface waves, Initial stress, Hexagonal crystals
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