Broadband low-frequency sound-absorbing metastructure based on an impedance-matching coiled-up cavity with continuously variable cross section

FEA Based Frequency Optimization Of Duct With Variable Cross Section Through Structural Modifications For Avoiding Resonance

Ducts are used to carry fluid in various applications in HVAC systems, thermal power plants, cement and other process industries. Such ducts are generally subjected to failure due to cyclic stresses either caused by high temperature fluctuations, mechanical vibrations or due acoustic vibrations caused due to the fluid flowing through the ducts. In this paper we study the failure of one such duc...

Cross-Modal Frequency Matching: Sound and Whole-Body Vibration

Interest in human responses to whole-body vibration has grown, particularly due to the increasing usage of vehicles, e.g. cars, trucks, and helicopters etc. Another reason for growing interest in recent years is the importance of the vibrations generated by the performance of music for multimedia reproduction systems. There is a strong relationship between the frequency of the auditory stimulus...

Interfacial structure designs with impedance-matching for ideal broadband antireflections

Broadband and Low Frequency Vibration-based Energy Harvesting Improvement through Magnetically Induced Frequency Up- Conversion

In order to extract as much energy as possible from ambient vibrations, many vibration-based energy harvesters (VEHs) are designed to resonate at a specific base excitation frequency. Unfortunately, many vibration energy sources are low frequency (0.5 Hz-100 Hz), intermittent, and broadband. Thus, resonant VEHs would not be excited continuously and would require a large mass or size to tune to ...

A continuously variable frequency cross-correlation phase fluorometer with picosecond resolution.

A detailed description of the construction and performance of a variable frequency cross-correlation phase fluorometer is reported. The phase fluorometer operates over the frequency range 1-160 MHz with a maximum resolution of a few picoseconds. The effects of distortions introduced by the light modulator and the nonlinear dynode characteristic are discussed in terms of the harmonic content of ...