Monitoring hydration characteristics of cement paste by EMI method
A monitoring system, which employs a piezoelectric ceramic as an active sensing transducer, is proposed for monitoring hydration characteristics of cement paste based on the electromechanical impedance (EMI) method. An impedance analyzer was used to obtain the electrical response of the sensor and the EMI measurements were performed by an online technique. The obtained data were analyzed using root mean square deviation (RMSD), a common statistical algorithm used for comparative processing of EMI spectra. The results show that the developed monitoring system is able to effectively detect physical changes of cement paste during the initial hydration.
An automated electrical monitoring system (AEMS) to assess property development in concrete
Abstract Electrical impedance measurement techniques are being increasingly used to measure material property development and permeability of concrete and other cement based materials. This paper describes the development of an automated electrical measurement system (AEMS) for measuring the properties of cementitious materials. The components of this system are an electrical impedance spectrometer, a digital multi-meter, a switching unit, and a customized software (AEMS) which communicates between different components of the system to control the testing and to collect data. This system enables electrical properties of multiple specimens to be measured in an automated fashion thereby making this approach very amenable for use in quality control applications. Further, an extension of this system is proposed which would enable its use to detect flaws in concrete using electrical imaging.
Experimental study of thermal modeling for stratospheric platform airships
R&D work on the Japanese stratospheric platform airship is discussed from the viewpoint of the thermal modeling. The work includes two experiments on the thermal characteristics of the 25m-long airship and the 35m-long PV-equipped airship model. The validity of the current thermal model was confirmed by comparing the calculated results with the measured data. The other important work is the Ground-to-Stratosphere (GTS) flight test. A 47mlong airship-shaped balloon was flown to the stratosphere. The flight simulation program into which the thermal model was integrated, was developed and applied successfully to predict the ascent behavior and the flight trajectory.