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EN
Robotics and its applications have become increasingly important in the field of manufacturing industry. Robot manipulators are effectively used for this purpose. Control of manipulators is very important, however, highly nonlinear and multi-input multi-output (MIMO) complex structure of manipulators make the control difficult. This paper presents two-degree of freedom PID controller scheme for a six-degree of freedom rigid robotic manipulator. Traditional PID controllers are widely used due to their simple control structure and ease of implementation in industry. However load disturbances and parametric variation affect the robustness of the controller. The performance of proposed two-degree of freedom PID controller is compared with the traditional PID controllers. Matlab-Simulink program is used for real-time implementation of the proposed method. Experimental results show that two-degree of freedom PID control is better than the traditional PID for manipulator control in real time.
EN
Pumping stations are some of the most important facilities of water administration. Continuous operation of these facilities is of utter importance, to be able to serve at all times. Maintenance of these facilities is also crucial for uninterrupted operation. In this study, the functioning of the predictive maintenance technique, which is based on the vibration analysis, is briefly addressed, and the application of the technique in a real system is presented. In the real system, the steps that must be done in order to apply this system are shown step-by-step. At the end of the study, the failures determined by using the predictive maintenance method are analyzed, and solution suggestions are presented.
EN
Vision based robot applications have taken a great deal of attention, with the development of electronic and computer technology. The visual feedback loop is very effective for improving the dexterity and flexibility. In this study, application of real time visual servoing approach is presented that enables a robot to robustly execute arm grasping and manipulation tasks. This task is decomposed on four stages a) finding object b) determining object's pose c) moving the robotic arm from an initial position towards the object d) grasping the object. The robot used in this work consists of an arm and head parts. The robotic arm has six degree of freedom, five degree of freedom are located at the arm while one degree of freedom is assigned to the gripper. Head has two degree of fredom which is pan-tilt platform. The image-based control strategy is designed using Fuzzy-PID controller. In this way, position error between target object and griper is minimized and the gripper can grasp the target object precisely. Real-time implementation of the proposed method is carried out using Matlab-Simulink. Experimental results show that, the developed design is valid to detect and grasp objects in real time.
EN
Drawbeads are often used in the sheet metal forming processes to provide a better control of the material flow into the die cavity. The drawbead restraint force (DBRF) and the exit thickness are two important sheet drawing characteristics to be determined for the selection and installation of the drawbead elements. This study presents the effects of drawbead geometry and sheet material on drawbead restraining force and thinning. Mathematical correlation between the drawbead geometry, sheet material and drawing characteristics was investigated by using Response Surface Methodology (RSM), which is a global approximation method ideally suited for solving highly nonlinear optimization problems. The proposed response surface model for DBRF and thinning showed a good correlation with the experimental data available in the literature. RSM could be considered as an alternative and practical technique to evaluate the sheet drawing characteristics. The method can also be applied to other sheet metal forming issue.
EN
The present study was designed to investigate the influence of acute ethanol intake and its withdrawal on the anticonvulsant effect of alpha-tocopherol in penicillin-induced epileptiform activity. Ethanol-treated rats received a daily dose of 3 g/kg or 9.0 g/kg of 30% ethanol solution for 3 days. Thirty minutes after penicillin injection (500 units, i.c.), the most effective dose of alpha-tocopherol (500 mg/kg) was administered intramuscularly (i.m.). Acute administration of ethanol, in a dose of 3 g/ kg, did not change either frequency or amplitude of penicillin-induced epileptiform activity, while dose of 9 g/kg ethanol significantly decreased the mean frequency of penicillin-induced epileptiform ECoG activity in the ethanol-treated group. Ethanol (9 g/kg) withdrawal also caused an increase in the amplitude of epileptiform ECoG activity in the withdrawal group. The results suggest that acute administration of high dose ethanol (9 g/kg) and alpha-tocopherol have some limited anticonvulsive effects in penicillin-induced epileptiform activity in rats.
EN
Iron plays an important role in maintaining normal brain function. However, in many neurodegenerative diseases abnormal iron accumulation in specific brain regions has been consistently reported. In this study, we investigated the neurotoxic effect of the intracerebroventricularly injected iron on the cerebellar Purkinje cells in the rat and the role of nitric oxide (NO) in this process. The role of NO in rats administered iron (FeCl36H2O) was examined with the use of a donor of NO, L-arginine (L-Arg), and a central selective inhibitor of NO synthase, 7-nitroindazole (7-NI). For this reason, rats were divided into 5 groups: control, iron-injected, iron plus L-Arg, iron plus 7-NI, and iron plus L-Arg plus 7-NI. Means (value ? standard deviation) of the total numbers of Purkinje cells in the cerebellum were estimated as 337 ? 23, 209 ? 16, 167 ? 19, 305 ? 26, and 265 ? 14 thousands in the control, iron, iron plus L-Arg, iron plus 7-NI, and iron plus L-Arg plus 7-NI groups, respectively. Iron treatment alone and the combination of iron and L-Arg caused a significant reduction in the total number of cerebellar Purkinje cells. Therefore, L-Arg increased the Purkinje cell loss induced by treatment with iron. These data show that inhibition of the neuronal NOS by 7-NI can prevent some of the deleterious effects of iron on cerebellar Purkinje cells. Presence of L-arginine decreased the neuroprotective effect of 7-NI.
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