Showing 5 results for Sobol
Mohammad Hossein Aliee, Ramin Roshandel, Akram Avami,
Volume 17, Issue 3 (5-2017)
Abstract
In today’s world, using of biogas is increasing due to its methane content, renewability, and low price. Solid oxide fuel cell is one of the best energy conversion technologies, in order to use biogas and it has a high potential to integrate with the gas turbine. In this paper, solid oxide fuel cell-gas turbine hybrid system, which is fed by biogas is modeled with respect to energy and economic aspects. Maximization of electrical energy efficiency and minimization of total investment cost are objective functions, which are considered to find the optimal design variables of the hybrid system. First, each component of the hybrid system is modeled and validated individually. Then, in order to optimize the hybrid system, multi objective optimization via NSGAII is implemented and optimal values of design parameters of the hybrid system were calculated. Optimal point is obtained using Euclidian non-dimensionalization and LINMAP decision making method in Pareto front. So, optimal design values are 66 percent and 175227.4 $, which are electrical energy efficiency and total investment cost, respectively. In optimal point Levelized unit cost is 6.3 cent per kWh. Finally, in order to determine the effect of design parameters on the objective functions, sensitivity of each design parameters were analyzed using Sobol's sensitivity analysis method. Results show that compressor pressure ratio has the maximum effect on electrical energy efficiency. Furthermore, turbine isentropic efficiency and fuel cell current have the maximum effect on the total investment cost.
M. Taheri,
Volume 19, Issue 1 (1-2019)
Abstract
Critical force and time are the two important output parameters in nanomanipulation of different particles. Various input parameters affect the critical force and time, among which dimensional parameters and velocity can be considered the most important ones. To accurately calculate the critical forces and time of the manipulation requires careful analysis of the effect of various input parameters. One of the new methods in affecting the sensitivity analysis of input parameters on problems are statistical sensitivity analysis methods, one of the most accurate methods of which is the Sobol method. Previously, research on the influence of various parameters on the 2D manipulation has been done. In this paper, for the first time, using Sobol statistical sensitivity analysis method, effects of various dimensional parameters, including length of cantilever, width of cantilever, thickness of cantilever, height of tip, the speed in direction of the x and y-axes, radius of the particle, radius of the tip needle, and length of particle have been studied on 8 output parameters, including critical force of sliding along the x-axis, rolling around the x-axis, sliding along the y-axis, rolling around the y-axis, and critical time of sliding along the x-axis, rolling around the x-axis, sliding along the y-axis, and rolling around the y-axis in 3D manipulation. The final obtained results demonstrate that “cantilever thickness” and “cantilever length” are the most influential parameters on critical forces, and “tip height” and “cantilever thickness” are the most influential ones on critical times.
A. Pak, H. Yaghooti, V. Tahmasbi,
Volume 20, Issue 5 (5-2020)
Abstract
The use of ultrasonic vibrations to reduce the temperature in bone drilling is one of the most important advanced processes that has attracted the attention of bone surgeons. Therefore, the study of temperature behavior in the ultrasonic-assisted drilling process and the prediction of temperature behavior have an important effect on improving the use of this method in orthopedic surgery. In this research, the influence of process parameters on change in the temperature was studied using response surface methodology and data analysis. Data analysis was carried out to find the effect of process factors such as rotational speed, feed speed, and ultrasonic vibrational amplitude and their interaction on the temperature. Moreover, using the statistical method of Sobol sensitivity, the effect, and sensitivity of each input factor on temperature were studied. The results show that the use of ultrasonic vibrations reduces the temperature, and rotational speed (%48), vibrational amplitude (%33) and feed speed (%19) had the greatest effect on temperature in ultrasonic-assisted bone drilling, respectively. As a result, the use of ultrasonic vibration can reduce the dependency of process temperature on the feed speed, and thus make it possible to perform surgery in a shorter time. The minimum temperature is 37°C at the rotational speed of 500rpm and the feed speed of 20mm/min and the vibration amplitude of 15μm.
Amin Sousanabadi Farahani , Mahdi Modabbarifar ,
Volume 23, Issue 10 (10-2023)
Abstract
The properties of metal-based composites, such as their high strength-to-weight ratio and good resistance to wear and fatigue, have caused a significant growth in their use in the aerospace, automotive, and aircraft industries. Magnesium-based composites have particularly attracted the attention of researchers in various fields, especially aerospace scientists, due to their lower density than other metal-based composite alloys such as titanium and aluminum. However, due to the presence of very abrasive reinforcing material in these materials, machining them is difficult and presents numerous challenges. Therefore, it to study the machining process of these is necessary composites and to examine the effect of the main turning parameters such as cutting speed, feed rate, and depth of cut on machining forces and surface roughness. Sobol's sensitivity analysis method was used for this purpose. Using this method, it was determined that the feed rate, cutting depth, and cutting speed have the greatest effect on the machining forces, respectively. Additionally, the feed rate has a greater effect on the surface roughness than the cutting depth and cutting speed. As the feed rate increases, the surface roughness and cutting forces increase.
Shayesteh Bashiri , Mohammad Khalili ,
Volume 23, Issue 10 (10-2023)
Abstract
The proper operation and quality of the finished product are highly dependent on the surface roughness of parts in a variety of industries. Among the most sophisticated techniques for reducing a part's surface roughness is the magnetorheological polishing procedure. This technique uses a magnetic field and rheological materials to improve the surface roughness of items. The parameters of turning radius, gap, machining time, magnetic pole rotation speed, and workpiece rotation speed have all been studied in the present research. By applying the Sobol method for statistical sensitivity analysis, the parameters have been examined via the surface roughness regression equation. According to the results, the most effective parameters are the workpiece's rotation speed (impact of 51%) and the magnetic pole's rotation speed (impact of approximately 21%). The next parameters to be considered are the machining gap (14% impact) and machining time (11% impact). With a 3% impact, the radius of gyration is thought to be the least important parameter in this process. This means that the time parameter's impact on this procedure can be neglected.
