Stress analysis of rotating functionally graded polar orthotropic disk under thermomechanical loading

In this paper, thermo-elastic stress analysis of rotating variable thickness annular disk made of polar orthotropic functionally graded material (FGM) is presented. Elasticity modulus, density and thick-ness of the disk are assumed to vary radially according to a power law function. The material of the disk is assumed to be temperature dependent and different temperature distributions are assumed for variation of the temperature in radial direction. Radial stress and radial deformation of the disk with Clamped- Free (C-F) and Free-Free (F-F) boundary conditions are obtained using the numerical finite difference (FD) method. It is concluded that, by increasing the temperature variation, the radial stress and displacement increase. It is also observed that the radial stress in the rotating FG disk is more than the radial stress in rotating homogeneous disk and by increasing the FG index, the location of maximum stress in the disk shifts toward the outer surface. Also, the effects of temperature variation along the radius and orthotropy of the material on the radial stress and deformation are evaluated and concluded that their effect are significant. The results are compared with the available results in the literature and the good agreement between the present results and results in the literature shows the accuracy of FD method in thermo-elastic analysis of rotating FG orthotropic disk of variable thickness

One-dimensional and two-dimensional Green-Naghdi equations for sloshing in shallow basins

This paper presents a verified model of weakly non-linear wave sloshing in shallow basins, based on level I Green-Naghdi (GN) mass and momentum equations derived for mild-sloped beds. The model is verified for sloshing of an initially sinusoidal free surface perturbation in a square tank with a horizontal bed. The model is also used to investigate free surface sloshing of an initial Gaussian hump in closed square basins, over horizontal and nonuniform bed topographies. Analysis of the free surface slosh motions demonstrates that the model gives predictions in satisfactory agreement with the analytical solution of linearised shallow water theory obtained by Lamb. Discrepancies between GN predictions and linear analytical solutions arise from the effect of wave non-linearities arising from the wave amplitude itself and wave-wave interactions

One-dimensional and two-dimensional Green-Naghdi equation solvers for shallow flow over uniform and non-uniform beds

Numerical simulation of wave behaviour in shallow and deep water is often a key aspect of ocean, coastal, and river hydrodynamic studies. This thesis derives nonlinear one- and two-dimensional level I Green-Naghdi (GN) equations that model the motions of free surface waves in shallow water over non-uniform bed topography. By assuming fitted velocity profiles through the depth, GN equations are simpler than Boussinesq equations, while retaining the wave dispersion property. Implicit matrix solvers are used to solve the spatially discretised 1D and 2D GN equations, with a 4th order Runge Kutta scheme used for time integration. To verify the developed numerical solvers of 1D GN equations, a series of simulations are undertaken for standard benchmark tests including sloshing in a tank and solitary wave propagation over a flat bed. In all cases, grid convergence tests were conducted. In the sloshing test, both numerical schemes and the analytical solution were in complete agreement for small-amplitude free surface motions. At larger values of initial sloshing amplitude, the nonlinear effects caused the free surface waves to steepen, and eventually the numerical simulations became unstable. This could be resolved in future using a shock-capturing scheme. Excellent agreement was achieved between the numerical predictions and analytical solution for solitary waves propagating. The 2D GN equation solver was then verified for the benchmark tests of Gaussian hump sloshing and solitary wave propagation in closed basin. The predicted free surface motions for Gaussian hump sloshing were in good agreement with linear Fourier analytical solutions for a certain initial period, after which nonlinear effects started to dominate the numerical solution. A reversibility check was undertaken. Nonlinear effects were investigated by increasing the amplitude of the hump, and applying harmonic separation (by comparison against slosh predictions for a corresponding Gaussian trough). It was found that the even harmonic components provided a useful indication of the nonlinear behaviour of the 2D GN equations. 2D GN simulations of a 0.6 m amplitude solitary wave propagation in 1 m deep water over a flat, horizontal bed confirmed that nonlinear interaction was correctly modelled, when the solitary wave hit a solid wall and its runup reached 2.36 m which was 0.36m more than the linear analytical solution and almost identical to a second order solution

A new applicable model of Iran rural e-commerce development

AbstractThe significant impact of e-commerce (EC) on the livelihood or rural populations in developing countries like Iran has made this topic of popular interest to many researchers in the past decade.To take advantage of e-commerce, employing suitable models which are adaptive to the circumstances of villages in rural areas is indispensable. Iran is on track for achieving this goal, development of EC in Rural areas.Considering the importance of sharing rural ICT experiences, the trend and experiences of the Rural EC infrastructure in Iran are demonstrated in this paper. According to our research, Iran’s rural ICT network development started in 2000 with the far northern village of Shahkooh which is known as the first multi-media center of Iran. In 2004, Iran national strategic plan of Rural ICT built two well-equipped telecentres near the villages of East Livan and Gharnabad. Taking availability of data and the duration of operation al time to account, these two telecenters were selected for this paper. In 2005, UNESCO Tehran Cluster Office was empowered to carry out a study on the economic and social effect of rural ICTs to share with others, acting in this field at regional and social levels. In fact, in order to find applicable and durable solutions for economic, social and environmental problems, these projects were carried out in the rural areas of Iran.In this paper, a practical model of e-commerce for rural areas of Iran is proposed. Our research is based on quantitative and qualitative methodologies. The qualitative methods comprised of open-ended interviews with officials and telecentre operators. The proposed model is related to the national project known as “10000 Rural ICT Center” which was started in the year 2004. In this project, Rural EC services are part of the IT application services at the Rural ICT Centers which supply four services; Communication Services, IT services, Postal Services and E-Banking services

The protective effect of vitamin E on rats’ ovarian follicles following an administration of diazinon: An experimental study

Background: Diazinon (DZN) is an organophosphate insecticide that has been widely utilized in agriculture all over the world and caused many negative effects on different species such as plants and animal species, especially on a human. Objective: The aim of the present study was to evaluate the protective effect of vitamin E on rats’ ovarian follicles following an administration of diazinon. Materials and Methods: A total of 30 adult female Wistar rats were divided into five groups: a control group (without any intervention), sham group (received only pure olive oil, as solvent), experimental group I (DZN+olive oil, 60 mg/kg), experimental group II (vitamin E, 200 mg/kg), and experimental group III (DZN: 60 mg/kg+vitamin E: 200 mg/kg). All drugs were injected intraperitoneally, except vitamin E which was administrated by gavage. The animals were sacrificed after two weeks and the left ovary was used to measure proliferation of ovarian follicles. Tissues were analyzed by the PCNA technique and viewed with an optical microscope for evaluating cell proliferation. Results: The result of the present study revealed that the number of proliferative cells in the experimental group I decreased significantly in contrast to the control group in secondary and Graffian follicles (p< 0.001). The administration of vitamin E plus DZN significantly increased proliferative cells compared to the DZN group (p< 0.001). Primordial follicles showed that all study groups were lacking PCNA positive cells, which means no expression of PCNA in these follicles. The results of this study showed that primary follicles in all study groups had a few and scattered PCNA positive cells with no significant difference between the groups (p> 0.05). Conclusion: Results showed that DZN reduced proliferation in secondary and Graffian follicles and vitamin E increased it. The results of this study suggested that vitamin E by its antioxidant activity was able to improve the DZN-induced ovarian toxicity. Key words: Diazinon, Proliferation, Ovary, Vitamin E, Rat

On the regularity of the Green-Naghdi equations for a rotating shallow fluid layer

The Green–Naghdi equations are an extension of the shallow-water equations that capture the effects of finite fluid depth at arbitrary order in the characteristic height to width aspect ratio H/L. The shallow-water equations capture these effects to first order only, resulting in a relatively simple two-dimensional fluid-dynamical model for the layer horizontal velocity and depth. The Green–Naghdi equations, like the shallow-water equations, are two-dimensional fluid equations expressing momentum and mass conservation. There are different ‘levels’ of the Green–Naghdi equations of rapidly increasing complexity. In the present paper we focus on the behaviour of the lowest-level Green–Naghdi equations for a rotating shallow fluid layer, paying close attention to the flow structure at small spatial scales. We compare directly with the shallow-water equations and study the differences arising in their solutions. By recasting the equations into a form which both explicitly conserves Rossby–Ertel potential vorticity and represents the leading-order departure from geostrophic–hydrostatic balance, we are able to accurately describe both the ‘slow’ predominantly sub-inertial balanced dynamics and the ‘fast’ residual imbalanced dynamics. This decomposition has proved fruitful in studies of shallow-water dynamics but appears not to have been used before in studies of Green–Naghdi dynamics. Importantly, we find that this decomposition exposes a fundamental inconsistency in the Green–Naghdi equations for horizontal scales less than the mean fluid depth, scales for which the Green–Naghdi equations are supposed to more accurately model. Such scales exhibit pronounced activity compared to the shallow-water equations, and in particular spectra for certain fields like the divergence are flat or rising at high wavenumbers. This indicates a lack of convergence at small scales, and is also consistent with the poor convergence of total energy with resolution compared to the shallow-water equations. We suggest a mathematical reformulation of the Green–Naghdi equations which may improve convergence at small scales.PostprintPeer reviewe