Study on the position control of the e-actuator for e-VGT
The e-VGT (electrical Variable Geometry Turbocharger), a kind of turbocharger is a electronic device that controls the flow rate and amount of exhaust gas. Therefore, the position of the actuator must be controlled quickly and accurately. To control the position of the e-actuator, the authors use PI control on a position controller including a current controller. However, since the e-actuator has big friction and spring force, a general PI controller isn't suitable for the e-actuator. To solve the problem, they find mechanical modeling of the e-actuator. And using the mechanical modeling, the controller that is suitable for the e-actuator is made.
Microprocessor-Based High-Efficiency Drive of a DC Motor
This paper presents a method to improve the efficiency of dc motors, dc shunt motors, and dc series motors. The method is based upon the field control. It is derived that the ratio of the armature current to the field current should be maintained constant to maximize the efficiency at a specific speed. The power circuits and the control loops are suggested to realize the principle, and the real-time control is implemented with a microprocessor. Also, in order to assess the stability of the overall systems, the proposed systems are analyzed with the small signal linearization. Experimental results show that the remarkable improvement in efficiency has been accomplished by the proposed method and the suggested systems are stable.
Thorium-induced Anatomical and Histopathological Changes in Liver of Swiss Mice
ObjectivePresent study is aimed to investigate the anatomical and histopathological changes in liver tissues of Swiss albino male mice, one month after intravenous administration of thorium (232Th; 4 and 40 mg/kg).MethodsSynchrotron X-ray micro-CT imaging, CD31 immuno-cytochemistry, hematoxylin & eosin staining and Periodic acid-Schiff staining were performed to study changes in liver anatomy, blood vessels/capillaries, histology and glycogen content of liver, respectively.ResultsSynchrotron X-ray micro-CT imaging of liver showed loss of blood vessels in mice treated with thorium (4 mg/kg), which was more prominent at higher dose of thorium (40 mg/kg). These thorium-induced changes in liver were correlated with the decrease in CD31 positive cells and loss of tissue architecture. A dose-dependent increase in glycogen content was also observed in the liver of thorium-treated mice.ConclusionOur results provide novel insight about the effects of thorium on liver, which may have significant implications in understanding the mechanism of thorium thorium-induced hepatotoxicity.