A New Method to Perform Direct Efficiency Measurement and Power Flow Analysis in Vibration Energy Harvesters.

Measuring the efficiency of piezo energy harvesters (PEHs) according to the definition constitutes a challenging task. The power consumption is often established in a simplified manner, by ignoring the mechanical losses and focusing exclusively on the mechanical power of the PEH. Generally, the input power is calculated from the PEH's parameters.

Efficient Modulation and Processing Method for Closed-Loop Fiber Optic Gyroscope with Piezoelectric Modulator.

This paper presents a simple method for compensating the Sagnac phase shift in an interferometric fiber-optic gyroscope (I-FOG) with a piezoelectric modulator. The common advantages of I-FOGs with closed-loop compensation are linearized output characteristics and insensitivity to the light source power, including its time and thermal-induced fluctuations. Whereas closed-loop operation is normally achieved via ramp modulation requiring an electro-optic modulator, all-fiber architectures with a piezoelectric modulator are mostly limited to open loop.

Non-negative intensity and back-calculated non-negative intensity for analysis of directional structure-borne sound.

Non-negative intensity (NNI) is an approach to identify the surface areas of a structure that contribute to sound power. NNI is evaluated in terms of the acoustic impedance matrix obtained directly at the structural surface and as such can only identify surface contributions to sound power at a far-field receiver surface that fully circumscribes the structure. In contrast, back-calculated NNI is evaluated in terms of the acoustic impedance matrix obtained at a far-field receiver surface, and hence can identify surface contributions to sound power at a far-field receiver surface that does not fully circumscribe the structure.