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This paper presents development of the spectral element method (SEM) for analysis of circular and annular circular plates vibration under impact load. A novel formulation is proposed in frequency domain for conducting spectral element matrix. Several numerical examples are presented in order to demonstrate performance of the presented method compared to other numerical methods in literature. The presented formulation was applied in order to analyze vibration of annular circular plates with various thicknesses and various internal-to-external radius ratios. In addition, annular circular plate displacements subjected to an impact load were calculated using the presented SEM.

In this study, two new moment resisting connections of beams to precast concrete columns under lateral load were analyzed via application of nonlinear finite element analysis software ABAQUS 6.10. The precast connections considered were the beam-column connections in which precast beams is connected to continuous precast column with corbel using (i) inverted E (bolted connection) and (ii) box section (welded connection). Connection responses associated with lateral resistance, lateral stiffness, ductility, and energy dissipation were compared to a reference monolithic connection. Achieved lateral resistance, lateral stiffness and ductility of the proposed connections was approximately 98%, 80% and 80% of the equivalent monolithic connection, respectively. The effect of axial load on column and compressive strength of concrete on behavior of the connections were studied. The analytical results show that the performance of two proposed precast connections were close to the performance of corresponding monolithic connection.

This paper presents a novel hybrid method coupling artificial neural network (ANN) and simulated annealing (SA), called ANN/SA to predict the fraction of pyrite remaining and therefore the pyrite oxidation rate in the wastes at different depths of a coal washing pile in the Alborz Markazi Coalfield, in northeast Iran. Waste depth, oxygen mole fraction and initial pyrite content in the waste particles were used as inputs to the network. The output of the network was the amount of pyrite content remaining. An ANN/SA model with Levenberg-Marquardt algorithm and a 3-4-3-1 arrangement showed a great capability. The network was used to predict the pyrite content remaining at two trenches E and F over the study waste pile once it was trained with the field-measured data. Simulated results obtained by the ANN/SA model were very closer to the experimental data compared to the outputs of simple ANN and multivariable least squares regression methods. The correlation coefficient (R) value, by the ANN/SA model, was 0.999 for training set, and in testing stage it was 0.998 and 0.99957 for trench E and trench F respectively which shows the model prediction was quite satisfactory. The performance of the model on the training and testing data, mean squared error (MSE) and mean absolute percent error (MAPE), indicate that it has both good predictive ability and generalisation performance.

A dynamic model was developed for long-term simulation of a heavy duty gas turbine. The model includes the essential control algorithm of the gas turbine as well as the most common outputs and other important intermediate variables. Control algorithm details, such as wind up protection and load limiter algorithm which have large effect on gas turbine transient behavior, are included. The model parameters are identified by applying genetic algorithm and least squares algorithm on regular operational data from a real plant to better match the model response to the real plant. The simulation results have been validated with real plant data and shown to have valid accuracy for many engineering applications.

A simple one-dimensional analytical solution is presented to model oxygen diffusion through the pore space of mine spoils containing pyrite. The model incorporates volumetric oxygen consumption terms due to pyrite oxidation, oxidation of Fe 2+ to Fe 3+ and bacterial activity. Based on this analytical solution, a graphical user interface (GUI) tool is programmed and designed in MATLAB software. This tool can be used to model transport of oxygen through the mine spoils either with or without a cap. Results of several simulation scenarios of sensitivity analysis showed a significant change in oxygen concentration with varying effective diffusion coefficient of oxygen transport model and simulation time. Efficiency and flexibility of the tool developed here is verified by modelling oxygen transport through the pore space of a coal waste pile (case A) and a copper mine tailings (case B). Maximum depth of oxygen diffusion is obtained approximately equal to 2 and 1.5 m through the cases A and B, respectively.

Single-shaft gas turbines are sensitive to frequency changes which might affect the grid stability during large frequency drops. This paper presents a new control system that uses steam injection as an auxiliary input to improve the transient performance of the gas turbine during frequency drops. Steam injection is beneficial because it reduces the peak temperature in the combustion chamber and augments the output power by increasing the mass flow through the turbine. The use of this auxiliary input is based on the event-based control approach. It means that during the frequency drop, the controller exploits the steam injection to help the main control loop recover the frequency and when the frequency reaches its predefined value, the system will return to its normal operation. The performance of the proposed control algorithm is investigated under different scenarios and the results show that the application of steam injection improves the performance of the regular control algorithm significantly, especially near full load condition.

The idea of active networks has been emerged in recent years to increase the processing power inside the network. The intermediate nodes such as routers will be able to host mobile agents and many management tasks can be handled using autonomous mobile agents inside the network. One of the important limitations, which should be considered in active networks, is the restricted processing power of active nodes. In this paper, we define an optimal location problem for monitoring mobile agents in a scalable active network as a p-median problem, which is indeed a kind of facility location problem. The agents are responsible to monitor and manage the performance of all of the network nodes such that the total monitoring traffic overhead is minimized. Then we proposed two methods of finding an appropriate sub set of intermediate nodes for hosting mobile agents. In our first method, we have not considered the limited processing power of active nodes, which host mobile agents. In our second method, we have solved the problem so that the processing loads of host nodes do not exceed a predefined threshold. Since p-median problems are NP-complete and the search space of these problems is very large, our methods are based on genetic algorithms. We have tested our two methods for finding mobile agents optimal locations on four network topologies with different number of nodes and compared the obtained location. By this comparison, we have shown the importance of considering processing load limitation for active nodes as a parameter in choosing them as hosts of mobile agents in a scalable active network. The proposed locations in our second method eliminates the probability of CPU overload in the active nodes hosting the mobile agents and reduces the processing time required for finding the optimal locations of mobile agents.

The advancement of technology has enabled new functions and possibilities for prosthetic devices. This advancement has introduced additional complexities for the user of the prosthetic devices. The added complexities can actually force the user to use simpler passive prosthesis rather than more complex and more flexible ones. This paper discussed the various aspects of the FUM Bionic Hand-I, designed and built at the Ferdowsi University of Mashhad. It also discusses the various efforts placed to simplify the usage of this prosthesis by its user. The FUM Bionic Hand-I has 5 degrees of freedom and consists of several sub systems such as pattern learning glove, wireless EMG Signal transmitter, RFID system for identify objects and a rich graphical user interface (GUI). These features works simultaneously in order to minimize the users' efforts on control a prosthetics hand and makes the hand intelligent enough to cooperate with user. Finally, the paper discusses the force control capability of the hand in order to allow object grasping.