Effect of erbium-calcium manganite doping on microstructure and electrical properties of zinc oxide based varistor ceramics

In this research, (80-x) mol% zinc oxide with 20 mol% CaMnO3 as the additive and (x) mol% erbium oxide Er2O3 as the doping material where x = 0.5, 1.0 and 1.5. Aims of this work are to elucidate the effects of doping material on microstructure ZnO and nonlinear characteristics of ZnO based varistor ceramics. A compound comprising ZnO-CaMnO3-Er2O3 underwent pre-sintering at 500 °C for 4 hours and sintering process at temperature of 1100 °C, 1200 °C and 1300 °C with the soaking time of 1.5 hours and 4.5 hours. X-ray diffraction patterns CaMnO3   spinal  and  additional  phases  containing Er in the confirmed the presence of synthesized compounds.The disappeared of hydroxyl and carbonyl functional group was observed at 3600-3650 cm-1, 1421 cm-1 and 875 cm-1 respectively by Fourier Transform Infrared spectroscopy to indicate the starting formation oxide metal upon calcinations.Keywords: ZnO varistor; Er doping; microstructure; I-V characteristics; low voltage varisto

Development of an Arm Rehabilitation System with Different Control Approaches

Stroke rehabilitation plays a vital role for people with limb disability because of stroke attack. Due to gradually increasing medical prices, the cost of rehabilitation devices existed in the hospital and rehab centre are simultaneously increased. These devices also lack the features that help to ease and increasethe spirit of patients during the rehabilitation process. Thus, this paper aim to create an arm platform-based for upper limb rehabilitation, where the interactive game features also created by using Unity 2D software for the purpose of motivating patients during the rehabilitation process. The main target is to develop an arm platform, which is focused on proper controller design for the active exercisesin early-stage therapy. The performance of the arm platform is examined in term of range of motion. Therefore, it will reduce patient’s pressure during the exercise and gradually improve their agility. In the proper control of the muscle tension, the designed upper limb rehabilitation exoskeleton device will providean improvement in muscle strength and proper posture for an arm