Introduction: Hospital Emergency Departments (ED) face different problems affecting their performance. Deficiency of inpatient beds, inability to access suitable care, noisy and overcrowded places, etc. lead to prolonged waiting time, increased length of stay and low service quality.The main purpose of this study was to improve patient flow Processes in emergency departments.Method: The population of this descriptive- applied study included unlimited number of patients who referred to the ED of the selected hospital. Colored Petri Net was used to model patient flow Processes and CPN Tools software was employed to simulate and investigate different improvement scenarios. Input data for the simulation model were obtained through timing during data collection period. Patients’ waiting time, length of stay, and resource utilization were defined as performance measures. Four improving scenarios (B, C, D, and E) were defined and their effects were investigated to improve Processes.Results: According to simulation outputs, scenario B led to 45% decrease in waiting time for the specialists while the other scenarios had no positive (decreasing) impact on waiting time. Scenario E was the most effective one in decreasing the length of stay for patients at different ESI levels.Scenarios E and D had positive effect on resource utilization.Conclusions: Selection of the best scenario depends on the mission of ED, i.e. to save patients’ life. Therefore, a scenario which is the most effective one in saving life must be chosen even if it is expensive. Although it is expensive, scenario E is preferred to scenario D due to its improved outcome. Scenario D is the second best scenario, compared to the other two scenarios, because it is less expensive.

In this research, it has been considered some direct applications of mathematics in the physical Processes simulation. This Study has divided in two phases, Fluids and Solids. In fluids, it has separately carried out at two really and imaginary coordinate flow around the same different shape, using mathematics relation has been considered.So the shape and flow by governing equations of that Processes has been simulated. So that the characteristic of flow at every point around the shape with high accuracy are computable. In continue the receipt method solving the equations has explained. In the solids branch, the motions of float bodies in the water studied using of mathematics relations. simulation has been made by mass, restore, damper and use of governing equations, In this study a software derived that calculate the hydrodynamic parameters and also the spectral of wave power due to body float motions.

Chip removing in the machining Processes is done through the forces. Therefore, prediction of the forces and estimation of required energy is very important for determination of the efficiency of these operations. In this investigation first, by using Hooputrsa’s shear damage model in the ABAQUS/Explicit code, a number of conventional machining Processes such as plane milling, straight turning, face turning, and drilling are simulated. By performing the simulations, variations of the force acting on the tool, maximum force, and also chip formation mechanism in each of the above Processes are predicted. Then, in order to evaluate the shear damage model and material properties, the simulation results are compared with the results of theoretical and experimental relations. Comparison of the numerical and empirical results reveal that the Hooputraa’s shear damage model can well predict the damage initiation and evolution, chip formation, and forces acting on the tool in the machining Processes.

A molecular dynamics simulation study has been performed to investigate the solidification and remelting of aluminum using Sutton-Chen many body potential. Different numbers of atoms from 108 to 2048 atoms were considered to find an adequate size for the system. Three different cooling and heating rates, i.e. 1012 K/s, 1013 K/s and 1014 K/s, were used. The structure of the system was examined using radial distribution function. The melting and crystallization temperatures of aluminum were evaluated by calculating the variation of heat capacity during the phase transformation. Additionally, Wendt–Abraham parameters were calculated to determine the glass transition temperature. It is shown that the melting temperature of aluminum increases as the heating rate increases. During solidification, a crystalline or amorphous-like structure is formed depending on the cooling rate. Remelting of the amorphous solidified material is accompanied by crystallization before melting at heating rates<1014 K/s. The melting temperature also depends on the degree of structural crystallinity before remelting.

Nodaway, membrane methods such as ultrafiltration have been considered to separating pollutions from fluids. The governing equations indicate the role of cartridge geometry on the separation process. The present study is carried out to investigate the effect of cartridge geometry on the separation performance of a hollow fiber ultrafiltration system. Numerical Modeling are divided into three categories, include circle, square, and triangle. The region including fibers is considered as a porous medium. Results show in the same conditions, the use of square and triangular geometry reduce transemembrane pressure, cake thickness and consequently the cake resistance and the membrane resistance compared to circle. Also, triangle geometry has shown better performance under changes in inflow and packaging density and the time to reach the same thickness of the cake is more than the other two geometries.