Design FPGA-Based CL-Minimum Control Unit

Farzin Piltan,Omid Avatefipour,Samira Soltani,Omid Mahmoudi,Mahmoud Reza Safaei Nasrabad,Mehdi Eram,Zahra Esmaeili,Sara Heidari,Kamran Heidari,Mohammad Mahidi Ebrahimi 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.1

Most of controllers need real time mobility operation so one of the most important devices which can be used to solve this challenge is Field Programmable Gate Array (FPGA). FPGA can be used to design a controller in a single chip Integrated Circuit (IC). To have higher implementation speed with good performance cMinimum Control Unit (MCU) is implemented on Spartan 3E FPGA using Xilinx software. Design a 4 bits Field Programmable Gate Array (FPGA)- based carry lookahead MCU is the main challenging works. MCU is control unit to control of data transfer between input and output and process the input data. In this research, MCU is used to control the 4 bits, Arithmetic Logic Unit (ALU). Combinational logic characterized by its propagation delay and contamination delay. To reduce the delay hardware description language (HDL) type of programming is very important. To reduce the route delay and logic delay, type of HDL design is very important. In this research, we used lookahead design, which reduce about 10% delay in comparison with ripple carry.

Fuzzy Hype-Plane Variable Sliding Mode Control to Reduce Joint Vibrations

Mahmoud Reza Safaei Nasrabad,Ehsan Pouladi,Ghasem Sahamijoo,Alireza Salehi,Farzin Piltan,Nasri b. Sulaiman 보안공학연구지원센터 2014 International Journal of u- and e- Service, Scienc Vol.7 No.5

The sliding mode controller is used to speed up the error convergence when the error is greater than one. To reduce the error terminal sliding mode controller is recommended in this research. Fuzzy hype-plane variable sliding mode controller is adopted to guarantee the error convergence to zero in a finite time when the error is around the zero. The chattering in the conventional sliding model control systems is avoided with the employed continuous controller. To increase the system robustness in presence of uncertainty fuzzy logic controller is recommended. This technique is used to adjust the band of terminals. The simulation results show that the proposed scheme has strong robust against the uncertainties and disturbances, as well as leads to the convergence of the output to the desired value quickly and precisely than employing either sliding mode controller or terminal sliding mode controller alone.

Production of Ultrafine-Grained Titanium with Suitable Properties for Dental Implant Applications by RS-ECAP Process

Mehdi Abbasi,Farshid Ahmadi,Mahmoud Farzin 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.4

The only problem of pure titanium for dental implant applications is its low strength and failure under different loadings. Various studies have shown that the utilization of severe plastic deformation processes such as Equal Channel AngularPressing (ECAP), through reducing the grain size of titanium, can improve not only its mechanical properties but also itscorrosion resistance and biocompatibility. In this study, a reduced-scale ECAP process on pure titanium was performed toinvestigate the effects of scale reduction. An ECAP die was made with an internal diameter of d = 3 mm, and the tests wereperformed at 250 °C for several number of passes. It was found out that after 10 passes of reduced-scale ECAP, the grainsize of CP Ti had strongly been reduced from 25 to 122 nm. This sharp reduction in grain size resulted in an increase inmicro-hardness from 205.5 to 321.3 Hv. Moreover, Nano-hardness test results showed that after 10 passes, the hardness oftitanium increased from 2461 to 3812 MPa, and simultaneously elastic modulus decreased from 108.1 to 94.8 GPa. Suchreduction of elastic modulus of titanium for dental implant applications decreased stress-shielding and jaw bone damages. According to the results of this research, after RS-ECAP process the strength of titanium is greatly increased and its elasticmodulus is reduced, which are desirable features for dental implant applications. Since dental implants are small in size, thereduced ECAP process (d = 3–5 mm) can produce titanium implants with improved properties.

Experimental and Numerical Study of the Critical Length of Short Kenaf Fiber Reinforced Polypropylene Composites

Mohammad Nematollahi,Mehdi Karevan,Marzieh Fallah,Mahmoud Farzin 한국섬유공학회 2020 Fibers and polymers Vol.21 No.4

Widespread attention to make use of biodegradable resources as a replacement for petroleum products leads to theexploitation of natural fiber reinforced composites. Natural fiber reinforced polymer composites usually exhibit lowermechanical properties than synthetic fiber ones. Thus, understanding key factors affecting the overall mechanical propertiesin order to increase them is crucial. One underlying factor is the length of fiber highly contributing to the extent of matrix/fiber interfacial load transfer at the interface. However, the concurrent examination of the load transfer mechanism at theinterface of fiber/matrix in terms of fiber length has not been well performed using computational, analytical andexperimental approaches. This work is aimed at the determination of the critical fiber length associated with a full loadtransfer condition using various methods to better understand their accuracy and the interfacial load transfer mechanism. Forthis purpose, specimens of neat polypropylene (PP) and 20 wt% kenaf/PP composites were fabricated using extrusioninjection molding. Tensile testing, scanning electron microscopy and density measurements were conducted to incorporatethe obtained results into the models and to verify the results predicted by the models. A three dimensional representativevolume element (RVE) representing the filler content of fabricated specimens was assumed. A micromechanical model wasemployed to make the results of analysis independent of the RVE dimensions. The critical fiber length for a full load transferwas determined by evaluating the stored elastic strain energy changes against the fiber length. The results showed that thekenaf fiber length is critical to both the load transfer efficiency and stiffening of composites. The results further revealed thatto obtain the full interfacial load transfer, the length of kenaf fibers needs to be greater than the critical length being ~2.4 mmprovided that perfect kenaf/PP interfacial interaction exists.

Improving the Quality of Surface in Polishing Process with the Magnetic Abrasive Powder Polishing (MAPP) by Use of Ultrasonic Oscillation of Work-piece on a CNC Table

Saeed Mirian,Mohsen safavi,Alireza Fadaei,Mahmoud Salimi,Mahmoud Farzin 한국정밀공학회 2011 International Journal of Precision Engineering and Vol. No.

In this research work, polishing inside, outside and over the cylindrical parts has been done by using a completely new and innovative method. The work-pieces have been placed on a two-axis Cartesian CNC Table for polishing operations. The Magnetic Rotary Head continuously changes its rotation direction from CW to CCW and CCW to CW and meanwhile the part begin to oscillate up-and-down under a High Frequency (20 kHz) conditions. The Frequency of changing direction From CW to CCW and CCW to CW is one of the important parameters in this method. This method is a kind of Ultrasonic Assisted Polishing (UAP) and novelty of this research work is combining this method with motion of work piece under CNC trajectory with continuously changing direction of Magnetic Rotary Head. Gap between Rotary Magnetic Polishing Head and the Work piece Surface can be controlled by a power transmission screw which operates in the direction of the vertical axis. Several experiments have proved high performance of this new proposed method in the process of polishing in short times.

An approach to improve thickness distribution and corner filling of copper tubes during hydro-forming processes

GhorbaniMenghari, Hossein,Poor, Hamed Ziaei,Farzin, Mahmoud,Alves De Sousa, Ricardo J. Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.50 No.4

In hydroforming, the general technique employed to overcome the problem of die corner filling consist in increasing the maximum fluid pressure during the forming process. This technique, in other hand, leads to other difficulties such as thinning and rupturing of the final work piece. In this paper, a new technique has been suggested in order to produce a part with complete filled corners. In this approach, two moveable bushes have been used. So, the workpiece moves driven by both bushes simultaneously. In the first stage, system pressure increases until a maximum of 15 MPa, providing aninitial tube bulge. The results showed that the pressure in this stage have to be limited to 17 MPa to avoid fracture. In a second stage, bushes are moved keeping the constant initial pressure. The punches act simultaneously at the die extremities. Results show that the friction between part and die decreases during the forming process significantly. Also, by using this technique it is possible to produce a part with reasonable uniform thickness distribution. Other outcomes of applying this method are the lower pressures required to manufacture a workpiece with complete filled corners with no wrinkling.

An approach to improve thickness distribution and corner filling of copper tubes during hydro-forming processes

Hossein GhorbaniMenghari,Hamed Ziaei Poor,Mahmoud Farzin,Ricardo J. Alves De Sousa 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.50 No.4

In hydroforming, the general technique employed to overcome the problem of die corner filling consist in increasing the maximum fluid pressure during the forming process. This technique, in other hand, leads to other difficulties such as thinning and rupturing of the final work piece. In this paper, a new technique has been suggested in order to produce a part with complete filled corners. In this approach, two moveable bushes have been used. So, the workpiece moves driven by both bushes simultaneously. In the first stage, system pressure increases until a maximum of 15 MPa, providing aninitial tube bulge. The results showed that the pressure in this stage have to be limited to 17 MPa to avoid fracture. In a second stage, bushes are moved keeping the constant initial pressure. The punches act simultaneously at the die extremities. Results show that the friction between part and die decreases during the forming process significantly. Also, by using this technique it is possible to produce a part with reasonable uniform thickness distribution. Other outcomes of applying this method are the lower pressures required to manufacture a workpiece with complete filled corners with no wrinkling.

A Novel Approach in Manufacturing Two-Stepped Tubes using a Multi-Stage Die in Tube Hydroforming Process

Hamed Ziaei Poor,Hossain Ghorbani Menghari,Ricardo J. Alves De Sousa,Hassan Moosavi,Mahboubeh Parastarfeizabadi,Mahmoud Farzin,Hamed Sanei 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.

Optimization of operating conditions is one of the most signicant issues concerning hydroforming the tubular components, includingstepped tubes, conical tubes, box shape tubes, and etc. Obtaining a sharp corner without any defects such as thinning and rupturingis one of the main goals in the production of these components. In order to manufacture tubes with filled corners, it is common toincrease the imposed pressure to the tubes. However, it may result in rupturing and thinning at the die corner radius, especially whenit is too small. In this paper, a new multistage die has been proposed for producing two stepped tubes. Numerical modeling has beenconducted using Abaqus/Explicit code. The results of simulation were afterwards checked against experiments in which it is shownthat a better thickness distribution could be obtained employing the proposed die set. There is no thinning in the final workpiece,particularly at the copper tube corners. Moreover, it could be possible to produce two stepped tubes with complete filled corners. Finally, comparing to other well-established methods, a lower pressure profile is required and a better thickness distribution can beachieved.