Influence of Tuning Fork Resonance Properties on Quartz-Enhanced Photoacoustic Spectroscopy Performance

A detailed investigation of the influence of quartz tuning forks (QTFs) resonance properties on the performance of quartz-enhanced photoacoustic spectroscopy (QEPAS) exploiting QTFs as acousto-electric transducers is reported. The performance of two commercial QTFs with the same resonance frequency (32.7 KHz) but different geometries and two custom QTFs with lower resonance frequencies (2.9 KHz and 7.2 KHz) were compared and discussed. The results demonstrated that the fundamental resonance frequency as well as the quality factor and the electrical resistance were strongly inter-dependent on the QTF prongs geometry. Even if the resonance frequency was reduced, the quality factor must be kept as high as possible and the electrical resistance as low as possible in order to guarantee high QEPAS performance.

A Clamped Bar Model for the Sompoton Vibrator

The sompoton is one of famous traditional musical instruments in Sabah. This instrument consists of several parts with the vibrator being the most important one. In this paper, the vibrator is modeled as a clamped bar with a uniformly distributed mass. By means of this model, the fundamental frequency is analyzed with the use of an equivalent single degree of freedom system (SDOF) and exact analysis. The vibrator is made of aluminum in different sizes and is excited using a constant air jet to obtain its fundamental resonance frequency. The fundamental frequency obtained from the experimental measurement is compared with the theoretical values calculated based on the equivalent SDOF and exact analysis theories. It is found that the exact analysis gives a closer value to the experimental results as compared to the SDOF system. Although both the experimental and theoretical results exhibit the same trend, they are different in magnitude. To overcome the differences in both theories, a correction factor is added to account for the production errors.

Positioning Performance Comparison Between Collocated Slider-Driven PZT Actuators and Conventional Suspension-Driven Actuators

The recording density of hard disk drives is achieving the physical limit due to the recording magnet size limitations. Therefore, the bit density BPI (Bits per inch) is saturated. The residual aim is to increase track density TPI (tracks per inch), because reducing mechanical track misregistration has a possibility of increasing TPI. The Dual Stage Actuator using a PZT microactuator which enables better positioning accuracy, is widely used in 3.5 inch high density drives. The latest PZT actuator called a “Milli” actuator drives the whole suspension. However, the mass of the suspension is around several milli-grams, thus the reaction force of PZT driving sometimes causes excitation to attached arm resonance at 8–9 kHz. In addition, the fundamental resonance frequency of a milli-actuator is around 20–25 kHz, the sway frequency of whole suspension.