All the producing and assembling processes exert residual stress on the pieces that may lead to structural failure. Therefore, calculating the residual stress in such structures has been common in recent years. In this article, distribution of temperature and residual stress resulting from arc welding in three-pass butt joint in P91 austenitic stainless steel pipes is calculated and estimated using the finite element method and experimental data. Simulating the welding process has been carried out three- dimensionally using Abaqus software. Distribution of the arc thermal flux has been identified based on the Goldak two-elliptical model using DFLUX subprogram in Abaqus software. The numerical method has been employed by doing thermoelastoplastic analysis and the technique of birth and death of the elements to model the welding passes and the melted elements. Then, using central hole drilling method, residual stress gradient of the thickness at distance 3mm from the welding line on the pipe is measured. Finally, the maximum percentage of error, through the results obtained from experimental measurements and finite element method, was reported 27% which is scientifically reasonable. The results show that the residual environmental stress in the internal surface of the pipe from the welding central line to 8.7mm varies with the gradient of 610MPa from 296MPa to -314MPa. Such a drastic stress distribution leads to genesising some cracks on the welded pipes. تفاصيل المقالة

Surgeries, such as orthopedic surgeries, are always performed with the use of a free hand with the aid of a fluoroscopic device to drill and place the screw in the bone position. However, such surgeries are of high risk and radioactive contamination, and have long surgery duration. Since the drilling process is very important and usually depends on the skill of the surgeon, a teleoperation system is provided to perform this task. In order to gain better control over the patient's body by the surgeon, an impedance control algorithm that incorporates the robot's position and velocity signal along with the surgeon's hand force and bone response force is provided in order for the surgeon to have proper control over the surgical process. Finally, drilling operation is performed on a cow bone to evaluate the teleoperation system presented. The results of the teleoperation system show that the desired system is acceptable under the proposed control algorithm. The results show that the drilling tool on the cow bone correctly follows the surgeon's hand position and the surgeon correctly feels the force applied to the tool by the cow bone. تفاصيل المقالة

Nowadays scientists are looking for decreasing dental faults by presenting new approaches.It is obvious that comprehensive information about the anatomic position of the inferior alveolar neuralcanal is essential to have the most ideal mandible surgery or systemic tooth implant. Accordingly, wepresent a new approach in this article that can be used to have 3D segmentation and recognition of thementioned canal in mandible by CBCT image. This approach includes two main steps. In the first step,we train a full convolutional 3D net (FCN) to reach the ability of section recognition, which can recognizethe relevant area of mandible bone. And in the next step, we define a 3D U-net, which is similar to FCN,to segment the inferior Alveolar neural (IAN) canal from the lower jaw. Evaluated on publicly availabledatasets, our method achieved an average Dice coefficient of 86.61%. تفاصيل المقالة

Non-Destructive Testing & Evaluation methods are developed to inspect and investigate materials and structures. Ultrasonic Testing is an NDT method can be used for measuring the thickness of objects, as one of its significant applications. The objective of this paper is designing and applying an intelligent UT fuzzy control system for evaluating the thickness of thin metal objects in a range of 5-20 mm. The designed Fuzzy Logic Controller has five variables including four inputs and one output. The inputs are frequency of probe, couplant's acoustic impedance, object’s acoustic impedance, and temperature; also the output is thickness, particularly of thin objects. This suggested method has been applied to four metals. Our strategy consists of three steps; and it has been preferred to utilize pulse-echo method because of using the immersion method. The experimental results imply that the proposed procedure has been able to control and measure the thickness of thin objects (5-20 mm) successfully within a rate of mean error of 0.5%. تفاصيل المقالة

Electromechanical wrist hand orthosis1 is used under different conditions. It can be used for stabilitypurposes for a wide range of wrist movements. Do not bend the joints or prevent excessivepropagation. The materials used include low-temperature2 thermoplastic metal and thermoplasticsheets. To move the orthosis, a servomotor is used to move the wrist, which is controlled by theuser interface. Instead of expensive fittings, a simple aluminum watch joint has been used to makeit. To produce EWHO, first, the orthosis was designed by Inventor software. Depending on thewrist force, which is tolerable to the hand, this amount of force is analyzed on the sheets used inAbaqus software and Inverter software and analyzed for stress and ultimate stress. A Bluetoothboard controls the movements of the wrist according to the user's command in the app depending onthe type of user on the mobile or computer. The person or companion beside the person can helphim or her to adjust the orthosis. Depending on one's disability, the orthosis can be adjusted tovarying degrees and lead to one's recovery.The goal of this orthosis is to help patients withfunctional impairment in the wrist. Any type of functional disorder in his or her hand can result inthe loss of individual independence and thus a threat to his or her social independence. تفاصيل المقالة