Effect of length on the fundamental resonance frequency of arterial models having radial dilatation

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.

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Actuation and dynamic mechanical characteristics of a core free flat dielectric electro-active polymer soft actuator

JOURNAL OF MECHANICAL ENGINEERING AND SCIENCES ◽

10.15282/jmes.14.4.2020.08.0582 ◽

2020 ◽

Vol 14 (4) ◽

pp. 7396-7404

Author(s):

Abdul Malek Abdul Wahab ◽

Emiliano Rustighi ◽

Zainudin A.

Keyword(s):

Theoretical Model ◽

Resonance Frequency ◽

Dynamic Testing ◽

Experimental Results ◽

Percentage Error ◽

Initial Tension ◽

Average Percentage ◽

Soft Actuator ◽

Average Percentage Error ◽

Mechanical Dynamics

Various complex shapes of dielectric electro-active polymer (DEAP) actuator have been promoted for several types of applications. In this study, the actuation and mechanical dynamics characteristics of a new core free flat DEAP soft actuator were investigated. This actuator was developed by Danfoss PolyPower. DC voltage of up to 2000 V was supplied for identifying the actuation characteristics of the actuator and compare with the existing formula. The operational frequency of the actuator was determined by dynamic testing. Then, the soft actuator has been modelled as a uniform bar rigidly fixed at one end and attached to mass at another end. Results from the theoretical model were compared with the experimental results. It was found that the deformation of the current actuator was quadratic proportional to the voltage supplied. It was found that experimental results and theory were not in good agreement for low and high voltage with average percentage error are 104% and 20.7%, respectively. The resonance frequency of the actuator was near 14 Hz. Mass of load added, inhomogeneity and initial tension significantly affected the resonance frequency of the soft actuator. The experimental results were consistent with the theoretical model at zero load. However, due to inhomogeneity, the frequency response function’s plot underlines a poor prediction where the theoretical calculation was far from experimental results as values of load increasing with the average percentage error 15.7%. Hence, it shows the proposed analytical procedure not suitable to provide accurate natural frequency for the DEAP soft actuator.

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Observation of Magnetoelectric Effect and Tuning of Ferromagnetic Resonance Frequency using Bilayers Formed of Bulk YIG and PMN-PT

10.1557/proc-1110-c06-34 ◽

2008 ◽

Author(s):

Jacob H. Leach ◽

Vladimir Kovalskii ◽

Vitaliy Avrutin ◽

Ümit Özgür ◽

Hadis Morkoç

Keyword(s):

Resonance Frequency ◽

Ferromagnetic Resonance ◽

Magnetoelectric Effect ◽

Ferromagnetic Resonance Frequency

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Influence of Bone Quality, Drilling Protocol, Implant Diameter/Length on Primary Stability: An In Vitro Comparative Study on Insertion Torque and Resonance Frequency Analysis

Journal of Oral Implantology ◽

10.1563/aaid-joi-d-19-00145 ◽

2020 ◽

Vol 46 (3) ◽

pp. 182-189 ◽

Cited By ~ 1

Author(s):

Davide Farronato ◽

Mattia Manfredini ◽

Michele Stocchero ◽

Mattia Caccia ◽

Lorenzo Azzi ◽

...

Keyword(s):

Resonance Frequency ◽

Bone Quality ◽

Frequency Analysis ◽

Primary Stability ◽

Mean Difference ◽

Insertion Torque ◽

Resonance Frequency Analysis ◽

Bone Response ◽

Implant Length

The aim of this study was to evaluate the influence of bone quality, drilling technique, implant diameter, and implant length on insertion torque (IT) and resonance frequency analysis (RFA) of a prototype-tapered implant with knife-edge threads. The investigators hypothesized that IT would be affected by variations in bone quality and drilling protocol, whereas RFA would be less influenced by such variables. The investigators implemented an in vitro experiment in which a prototype implant was inserted with different testing conditions into rigid polyurethane foam blocks. The independent variables were: bone quality, drilling protocol, implant diameter, and implant length. Group A implants were inserted with a conventional drilling protocol, whereas Group B implants were inserted with an undersized drilling protocol. Values of IT and RFA were measured at implant installation. IT and RFA values were significantly correlated (Pearson correlation coefficient: 0.54). A multivariable analysis showed a strong model. Higher IT values were associated with drilling protocol B vs A (mean difference: 71.7 Ncm), implant length (3.6 Ncm increase per mm in length), and substrate density (0.199 Ncm increase per mg/cm3 in density). Higher RFA values were associated with drilling protocol B vs A (mean difference: 3.9), implant length (1.0 increase per mm in length), and substrate density (0.032 increase per mg/cm3 in density). Implant diameter was not associated with RFA or IT. Within the limitations of an in vitro study, the results of this study suggest that the studied implant can achieve good level of primary stability in terms of IT and RFA. A strong correlation was found between values of IT and RFA. Both parameters are influenced by the drilling protocol, implant length, and substrate density. Further studies are required to investigate the clinical response in primary stability and marginal bone response.

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