Membrane bioreactor (MBR) is an effective technology for wastewater treatment and water reuse which is becoming increasingly popular due to its numerous applications and advantages over conventional activated sludge process. This novel technology have advantages of small footprint, high concentration of mixed liquor suspended solids (MLSS), high removal efficiency of chemical oxygen demand (COD), less production of excess sludge and to be reliable and simple to operate. Membrane fouling and its consequences, regarding plant maintenance and operating costs, has gained attention in recent years as a major obstacle for development of this technology. Various methods have been used to reduce membrane fouling and new solutions are frequently proposed and used.

Introduction: The issue of noise pollution is one of the concerns of most societies and industries because of their relationship to the environmental comfort of life or work of people are paying attention. The Aero-acoustics not only because of government regulations on the noise pollution, but also due to the increasing demand of the people's living standards and create a safe environment for farm animals is considered important. At the same time, products with high aero-acoustic performance will attract a lot of customers, which is in the interest of the global economy. Reducing current noise is often accompanied by a reduction in energy costs, resulting in durability of structures and improved product quality. Materials and Methods: Sound measurements were carried out at the wind tunnel in Tabriz Tractor Engineers Company. Using the measurements performed by the instrument, the sound levels were measured at different periods of the fan. In many practical applications that include turbulent flow, no noise has any specific tone and the sound energy is continuously distributed over a wide range of frequencies. In cases where broadband noise is present, statistical disturbance values easily calculated from the RANS equations can be used in conjunction with semi-experimental correlations and audio coordination to reveal some broadband noise sources. Based on the problem, the boundary condition is the type of "input velocity" for the input and "output pressure" for the output. It was also used to move the mesh to apply the rotary motion of the fan. The thermodynamic conditions at these boundaries should be considered. Results and Discussion: The accuracy of the simulation results data was verified with the measured data. In the laboratory results, the audio level is accompanied by an audio environment and an inverter and a belt that is about 15 db. With this in mind, the simulation results had a good agreement with experimental results. The velocity is a critical parameter in fan-related discussions. In the upper part of the fan, the speed of the air increases as the fan sucks, and this speed will increase as the fan approaches. In the second part, which includes the fan, for speeding objects, the speed will increase as the radius increases (due to the constant rotational speed), so the maximum speed will be at the tip of the blades. In the lower part of the fan, the speed will decrease as the fan impact decreases on the air molecules as well as the boundary layer behavior near the walls. As the speed and intensity of the turbulence are higher at the tip of the blades, hence the kinetic energy of these regions must also be higher. The kinetic energy of the turbulence in these areas is the highest. At the bottom of the fan, it is also observed that the kinetic energy of the turbulence has been relatively high, due to the existence of flow vortices that emerge from the fan period and the presence of positive and negative pressure (negative pressure due to suction of the fan center). The high pressure difference on both sides of the fluid particles causes a rotating flow in the particles, which affects the adjacent particles and causes vortex formation. Conclusions: The results showed that the numerical acoustic evaluation simulates the performance of the broadband band with good results and has good agreement with the effects of the current on the noise. Increasing the recognition of the factors and their effects on the fan noise level can help to reduce the noise effects of turbo-machines. Using numerical simulations in predicting and reducing noise, in addition to time saving, dramatically reduces costs by using direct methods and mechanical design physically. With regard to all aspects and calculations, it can be concluded that acoustic numerical simulation and broadband noise model have a good ability to analyze noise in fans and rotary machines.

Hydraulic performance of emitters plays a major role in the trickle (drip) irrigation system uniformity. But, manufacturing proper emitters is highly expensive and time consuming. On the other hand, the study of flow behavior of the water passing through emitters' channels is difficult because of their small size and complexity. Therefore, it seems that Computational fluid dynamics (CFD) can significantly contribute to the study of flow hydraulic characteristics in emitter channels. In the present study, the three emitter codes A, B and C were selected and their channels size determined using the Scanning Electronic Microscope (SEM) for taking the pictures of channels. The flow in emitters channels was simulated with the two software FLOW3D and FLUENT. In this study laminar and turbulence models were applied for the simulation of flow in emitters’ channels, the discharge for each emitter was calculated. Verification of the CFD simulation results with those obtained in laboratory showed that Relative error value (Er) for laminar model of FLUENT, turbulent model of FLUENT, laminar model of FLOW3D, turbulent model of FLOW3D was 4.0, 4.4, 5.3, 12.0 per cent respectively. Laminar model estimated emitters discharge less than turbulent model. Also, it was shown that in both models FLOW3D and FLUENT the error calculated for turbulent model is greater than laminar model and that FLUENT software is more efficient than FLOW3D in the simulation of flow within emitters’ channels. But, generally, it can be said that the two software tools can simulate flow in emitters' channels with a good accuracy.

In this paper, one-dimensional numerical optimization of lead-acid battery with finite-volume method is performed using the governing equations of battery dynamics. For validation, the present results are compared with previous studies which show good agreement. The demand for batteries with high energy and power has increased due to their use in hybrid vehicles. The major shortcoming of lead-acid batteries in industry is low energy and high weight; therefore, a cell with higher energy and lower thickness is designed by using particle swarm optimization based on developed simulation code, which is less time consuming and much faster than experimental method. The results of optimization show that an optimal battery that has 85 percent higher energy can be made with the same cell length. The results also show that an optimum cell battery can be obtained with a 25 percent decrease in weight and 23 percent in dimensions while keeping the energy content constant.