In this paper, recommended spiral passive micromixer was designed and simulated. spiral design has the potential to create and strengthen the centrifugal force and the secondary flow. A series of simulations were carried out to evaluate the effects of channel width, channel depth, the gap between loops, and flowrate on the micromixer performance. These features impact the contact area of the two fluids and ultimately lead to an increment in the quality of the mixture. In this study, for the flow rate of 25 μl/min and molecular diffusion coefficient of 1×10-10 m2/s, mixing efficiency of more than 90% is achieved after 30 (approximately one-third of the total channel length). Finally, the optimized design fabricated using proposed 3D printing method.

Application of the network equivalent concept for external system representation for power system transient analysis is well known. However, the challenge to utilize an equivalent network, approximated by a rational function, is to guarantee the passivity of the corresponding model. In this regard, special techniques are required to enforce the passivity of the equivalent model through a post processing approach that minimizes its impact on the original model characteristics. In this paper, the passivity is enforced by expressing the problem in terms of a convex Optimization problem that guarantees the global optimal solution. The convex Optimization problem is efficiently solved by recently developed numerical interior–point methods. This passivity enforcement is also global which indicates that the passivity enforcement in one region does not lead to passivity violation in other regions.

In the present study, the performance of the 2D single-phase supersonic ejector with working fluid of air is simulated in ANSYS CFX. The aim is to investigate the velocity field, pressure distribution, primary nozzle flow regime, and entertainment ratio in different operational conditions. The primary pressure inlet with bar and the secondary inlet as an opening with bar at different outlet pressures are simulated. The turbulence model is used. The sidewalls are considered symmetry boundary conditions and the no-slip condition is applied to the ejector walls. Then, the ejector geometry is optimized using Multi-Objective Genetic Algorithm (MOGA) in order to reach greater efficiency. Optimization is performed considering Geometric parameters including primary nozzle exit diameter, nozzle exit position, diameter, and length of the constant area section. Sensitivity analysis results show that the diameter of constant area section has major effect on the entertainment and pressure ratios as two objective functions. The nozzle exit position and external diameter of primary nozzle are the second and third dominant parameters that respectively influence the performance of the ejector, while the effect of constant area section length is negligible. Results indicate that by increasing the pressure ratio, the shock train moves upstream and at the design point, the last oblique shock is located in the exit of the constant area section, letting the remaining pressure recovery be done in the subsonic diffuser which reduces the pressure losses and increases the efficiency. Above the critical pressure ratio, due to the movement of the shock train to upstream weakening the shock strength, the suction pressure increases. Then, the pressure difference is reduced, leading to the lower secondary mass flow suction. The optimized ejector in the double choking condition has a % higher entertainment ratio and its operational range is enhanced by percent in comparison to the original geometry.

For making decisions in optimizing investments in road safety projects, it is required to establish a regular process for selecting the most suitable countermeasures to be provided to road safety planners and decision-makers. Using the model developed in this research, a given budget funded from the road agency may be distributed among all predetermined locations (sites or routes), considering: (1) applying the share assigned to each location, the best possible improvements are selected as the premiere strategy amongst all alternatives through which the highest benefit is resulted, and finally, the sum of net benefits for all locations is maximized, and (2) the sum of construction costs attributed to selected alternatives in all locations does not exceed the total project budget. A set of road safety measures is studied involving the items known as Geometric features and road design criteria. The features defined here consists of lane width and road surface quality, roadside hazard zones, horizontal curves, crest vertical curves and narrow bridges. The cost-benefit analysis and binary integer programming methods are used to develop economic appraisal and complete Optimization tasks. The Solver program (as an add-in to Excel) is the main tool to run the allocating process. The research economic appraisal and Optimization process consist of eight steps within which some criteria are applied to define, valuate, discount and compare the cost and benefit components of the analysis. The most important measure to estimate the safety benefits is a mediator variable which is broadly known as Accident Modification Factor (AMF). In this research, AMFs are extracted for each Geometric feature mentioned above using the current valid accident models in Iran. As a means to support the execution of the developed model, a software program contributing to running the process of resource allocation is provided.

The objective of this research is Geometrical Optimization of Half Toroidal Continuously Variable Transmission (CVT) in order to achieve high power transmission efficiency and low weight. After dynamic analysis of the system, the contact between the disk and the roller is modeled according to elasto-hydrodynamic lubrication principles. Accordingly, a computer model is created with Geometric, thermal and kinetic parameters as inputs of the system, to determine the efficiency and the weight of CVT. Results are compared to those obtained from models in other articles to confirm its validity. Geometric parameters are obtained by means of genetic Optimization algorithm, while Optimization parameters are power transmission efficiency and system weight. It is observed that regardless of weight coefficients assigned to power transmission efficiency and weight, difference between results are negligible. Also, the effect of oil film temperature, speed ratio and rotational speed of input disk on power transmission efficiency for optimized geometry is shown.

Nowadays, the number of oscillations applied to some parts reaches the range of 107 and higher. Recently, researchers have used ultrasonic fatigue tests to study the fatigue behavior in these parts. This device is considered because of the high frequency of loading and as a result, achieving a higher number of oscillations in a shorter time. There is no universally accepted standard for this test, therefore, one of the geometries that are often used as a sample in this test is the geometry in the form of an hourglass In this research, while investigating this geometry in order to achieve optimal geometry or achieve maximum stress, the effect of Geometric parameters on temperature increase during high-frequency vibration or the thermoelastic effect, which is known as one of the disadvantages of ultrasonic fatigue testing, has been investigated. This effect should also be minimized. For this purpose, the dimensions of the hourglass geometry were defined as parameters and its changes were investigated using the simulation. The results showed by decreasing the radius of curvature, along with the stability of the middle diameter and the diameter of the cylindrical part, the amount of stress increases and also the amount of temperature changes decreases. On the other hand, the diameter of the cylindrical part increases, while the middle diameter and the amount If the curvature is constant, it will increase the amount of stress and temperature. The above results were evaluated using the experimental arrangement and a good match was observed in them.

In this research, several different types of geometries have been compared to prevent the influence of an explosion wave on the glasses of the APCs. This was done using validation and then using LS-DYNA software. Pre and post-processing was done in LS-PrePost software. So, a mathematical function in this software was used to generate the pressure of the wave on the structure. In order to compare, the displacement parameter was used and the minimum total displacement of the structure as a criterion for optimal performance was considered. Also, two types of cosine curves, two types of polynomial curves (third and fourth order) and a flat blade are investigated. The results showed that for the use of a 150*100 mm2 square flat blade (which is half simulated according to the model's symmetry), the explosion of a wave coming from a distance of 75 mm on the adjacent sheet requires a sheet with a thickness of 11 mm. Using a curved blade, this thickness is reduced to 3 mm. According to the recent issue, the use of curved blades will lead to a sharp decrease in the weight of armored equipment.

Stereo-machine vision can be used as a space sampling technique, and the cameras parameters and configuration can effectively change the number of samples in each volume of space called the space sampling density (SSD). Using the concept of voxels, in this work, we presents a method to optimize the Geometric configuration of the cameras in order to maximize SSD, which means minimizing the voxel volume and reducing the uncertainty in localizing an object in a 3D space. Each pixel’, s field of view (FOV) is considered as a skew pyramid. The uncertainty region will be created from the intersection of two pyramids associated with any of the cameras. Then the mathematical equation of the uncertainty region is developed based on the correspondence field as a criterion for the localization error including the depth error as well as the X and Y axes error. This field is completely dependent on the internal and external parameters of the cameras. Given the mathematical equation of the localization error, the camera’, s configuration Optimization is addressed in a stereo-vision system. Finally, the validity of the proposed method is examined by the simulation and empirical results. These results show that the localization error is significantly decreased in the optimized camera configuration.

In this research, optimal design of trapezoidal labyrinth spillway has been investigated using Gray Wolf Optimization (GWO) algorithm with respect to hydraulic conditions. By choosing the assumed volume of spillway concrete as the objective function, after several running the model and trial & error, parameters of the algorithm such as iteration, number of wolves and the penalty coefficient were determined to be 1000, 30 and 1011, respectively and by five times of testing, at the 996th iteration, the optimal response of objective function was achieved. The obtained value from the proposed algorithm was compared to the real value and also the results of the Cuckoo Search (CS) algorithm, Genetic Algorithm (GA) and Differential Evolution (DE) in previous studies. Using GWO algorithm for designing the considered dam's spillway, made reduction of 40. 928% in amount of assumed concrete volume and increase the rate of discharge to 10. 71% than to real value, which showed a better performance compared to above algorithms. Significant reduction of the consumed concrete volume in the proposed spillway by using GWO algorithm indicates ability and necessity of using this algorithm to solve Optimization problems in the field of spillways.