A model has been developed for unsteady-state Simulation of non isothermal, gas absorption with chemical reaction in packed columns. The model is based upon the two film theory in each time step and finite difference technique is used to solve the governing system of partial differential equations. The constructed model is capable to predict the concentration of all components in both gas and liquid phases as well as the temperature of each phase along the bed in Dynamic and the final steadystate. Results of the model, subjected to various forcing functions were compared with the experimental data obtained from a pilot-plant gas absorption unit, where CO2 was removed from an AIR--- CO2 mixture into an aqueous monoethanolamine (MEA) solution.

This work is conducted to obtain mechanical properties of microtubule. For this aim, interaction energy in alpha-beta, beta-alpha, alpha-alpha, and beta-beta dimers was calculated using the molecular Dynamic Simulation. Force-distance diagrams for these dimers were obtained using the relation between potential energy and force. Afterwards, instead of each tubulin, one sphere with 55 KDa weight connecting to another tubulin with a nonlinear connection such as nonlinear spring could be considered. The mechanical model of microtubule was used to calculate Young’s modulus based on finite element method. Obtained Young’s modulus has good agreement with previous works. Also, natural frequency of microtubules was calculated based on finite element method.

In this paper we propose a Simulation study to carry out Dynamic analysis of CNTFET-based digital circuit, introducing in the semi-empirical compact model for CNTFETs, already proposed by us, both the quantum capacitance effects and the sub-threshold currents. To verify the validity of the obtained results, a comparison with Wong model was carried out. Our model may be easily implemented both in SPICE and in Verilog-A, obtaining, in this last case, the development time in writing the model shorter, the Simulation run time much shorter and the software much more concise and clear than Wong model.

Every year, thousands of people suffer from spinal cord injuries due to accidents or falls. The effects can be very upsetting, resulting in paralysis or loss of sensation. This sudden loss of mobility and senses causes significant stress on patients both physically and psychologically, such as demineralisation of bones, frequent skin problems pressure sores, increased incidence of urinary tract infection, impaired lymphatic and vascular capacities. Apart from the broken nervous connection, the joints are still physically connected. This has prompted engineers and physicians to come up with idea of artificially stimulating the muscles of paraplegics to produce certain desired leg movements, a technique commonly known as functional electrical stimulation (FES). The most common method of FES is to apply electrodes to the skin over the muscle and control the stimulation by the variation of potential and frequency. The first priority for rehabilitation engineering is to enhance the paraplegic’s health, which can be achieved by applying FES on the large muscles of their legs to exercise them. This type of exercise should be both enjoyable and convenient. One of the most promising exercises is cycling. These days FES has been used widely for cycle ergometry to reduce spasticity, reverse muscle atrophy, as well as increase cardio vascular fitness, muscle bulk, blood flow and bone density in the legs, and to reduce the chance of developing pressure sores and cardiovascular disorders such as orthopaedic intolerance. Cycling by means of FES is an attractive training method for spinal cord injured (SCI) subjects. FES-cycling performance is influenced by a number of parameters like seating position, physiological parameters, conditions of surface stimulation, and pedaling rate. Cycling using FES is also a very promising approach because it activates most of the muscle groups in the lower limbs under safety conditions. For this reason several methods of stimulation have been used according to the activated muscle groups, allowing for different control strategies. To obtain the desired leg motion, the stimulation is embedded into a control system, where the stimulator is controlled by a microcomputer. Measurements could then be made to give feedback to the control system so that the performance could be further improved. This paper presents the development of a strategy for cyclical motion control by controlling the torques of the lower limb joints. A humanoid model is developed in this study and used as a test-bed to develop a suitable strategy for motion control of leg joints to result in bipedal motion in the lower extremity, and to identify torque profiles in each joint in different bipedal sitting positions.  

In this paper, the Dynamic Simulation for a high pressure regulator is performed to obtain the regulator behavior. To analyze the regulator performance, the equation of motion for inner parts, the continuity equation for diverse chambers and the equation for mass flow rate were derived. Because of nonlinearity and coupling, these equations are solved using numerical methods and the results are presented. Additionally, the Dynamic analysis results consist of the output pressure change versus time, the displacement of the moving parts versus time, the regulator mass flow rate versus time and the output pressure versus mass flow rate in different controlling spring pre-loads. Furthermore, the sensitivity analysis is carried out and the main parameters affecting the regulator performance are identified. Finally, the results of the Dynamic Simulation are validated by comparing them with the experimental results.

Solid transport phenomena drastically affect rotary drying process. A change in any solid movement variable such as particle hold up or input flow rate results in a significant variation of heat and mass transfer rates. Therefore, in this research Dynamic study of these phenomena was conducted both experimentally and theoretically. Several experiments were performed employing an industrial granule dryer. The dryer length and diameter were 5 and 1 m, respectively. In each experiment one of the solid movement variables was changed and the resulting Dynamic change on the process was measured. The data was used to estimate the parameters of a Dynamic distributed parameter model of the system using Dynamic optimization method. The data were also employed to evaluate the model. The model predictions for solid hold up and outlet flow rate were compared with those of the experimental data. The average model error for solid hold up and outlet flow rate were 5.6% and 5.4 %, respectively.