Current Issue : April - June Volume : 2012 Issue Number : 2 Articles : 4 Articles
Piezoelectrics have widespread use in today�s sensor and actuator technologies.\r\nHowever, most commercially available piezoelectric materials, e.g., Pb [ZrxTi1-x] O3\r\n(PZT), are comprised of more than 60 weight percent lead (Pb). Due to its harmful effects,\r\nthere is a strong impetus to identify new lead-free replacement materials with comparable\r\nproperties to those of PZT. This review highlights recent developments in several lead-free\r\npiezoelectric materials including BaTiO3, Na0.5Bi0.5TiO3, K0.5Bi0.5TiO3, Na0.5K0.5NbO3,\r\nand their solid solutions. The factors that contribute to strong piezoelectric behavior are\r\ndescribed and a summary of the properties for the various systems is provided....
A brain-computer interface (BCI) is a communication system that can help users interact with the outside\r\nenvironment by translating brain signals into machine commands. The use of electroencephalographic (EEG)\r\nsignals has become the most common approach for a BCI because of their usability and strong reliability. Many\r\nEEG-based BCI devices have been developed with traditional wet- or micro-electro-mechanical-system (MEMS)-type\r\nEEG sensors. However, those traditional sensors have uncomfortable disadvantage and require conductive gel and\r\nskin preparation on the part of the user. Therefore, acquiring the EEG signals in a comfortable and convenient\r\nmanner is an important factor that should be incorporated into a novel BCI device. In the present study, a\r\nwearable, wireless and portable EEG-based BCI device with dry foam-based EEG sensors was developed and was\r\ndemonstrated using a gaming control application. The dry EEG sensors operated without conductive gel; however,\r\nthey were able to provide good conductivity and were able to acquire EEG signals effectively by adapting to\r\nirregular skin surfaces and by maintaining proper skin-sensor impedance on the forehead site. We have also\r\ndemonstrated a real-time cognitive stage detection application of gaming control using the proposed portable\r\ndevice. The results of the present study indicate that using this portable EEG-based BCI device to conveniently and\r\neffectively control the outside world provides an approach for researching rehabilitation engineering....
Cyber physical systems (CPSs) typically have numerous sensors monitoring the various physical processes involved. Some sensor\r\nfailures are inevitable and may have catastrophic effects. The relational nature of the diverse measurands can be very useful in\r\ndetecting faulty sensors, monitoring the health of the system, and reducing false alarms. This paper provides procedures on how\r\none may integrate data from the various sensors, by careful design of a sensor relationship network. Once such a network has been\r\nadopted, choices become available in real time for enhancing the reliability, safety, and performance of the overall system....
Conductometric semiconducting metal oxide gas sensors have been widely used\r\nand investigated in the detection of gases. Investigations have indicated that the gas sensing\r\nprocess is strongly related to surface reactions, so one of the important parameters of gas\r\nsensors, the sensitivity of the metal oxide based materials, will change with the factors\r\ninfluencing the surface reactions, such as chemical components, surface-modification and\r\nmicrostructures of sensing layers, temperature and humidity. In this brief review, attention\r\nwill be focused on changes of sensitivity of conductometric semiconducting metal oxide gas\r\nsensors due to the five factors mentioned above....
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