scholarly journals A Theoretical and Empirical Investigation of Design Characteristics in a Pb(Zr,Ti)O3-Based Piezoelectric Accelerometer

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3545
Author(s):  
Min-Ku Lee ◽  
Seung-Ho Han ◽  
Jin-Ju Park ◽  
Gyoung-Ja Lee
Keyword(s):  
Resonant Frequency ◽  
Empirical Investigation ◽  
Impedance Measurement ◽  
Inverse Relation ◽  
Electric Voltage ◽  
Trade Off ◽  
Piezoelectric Accelerometer ◽  
Design Variables ◽  
Design Characteristics ◽  
The Relationship

A theoretical and experimental study on the design-to-performance characteristics of a compression-mode Pb(Zr,Ti)O3-based piezoelectric accelerometer is presented. Using the metamodeling to approximate the relationship between the design variables and the performances, the constituent components were optimized so that the generated electric voltage, representing sensitivity, could be maximized at different set values of the resonant frequency (25–40 kHz). Four kinds of optimized designs were created and fabricated into the accelerometer modules for empirical validation. The accelerometer modules fabricated according to the optimized designs were highly reliable with a broad range of resonant frequency as well as sufficiently high values of charge sensitivity. The fixed (or mounted) resonant frequency was between 16.1–30.1 kHz based on the impedance measurement. The charge sensitivity decreased from 296.8 to 79.4 pC/g with an increase of the resonant frequency, showing an inverse relation with respect to the resonant frequency. The design-dependent behaviors of the sensitivity and resonant frequency were almost identical in both numerical analysis and experimental investigation. This work shows that the piezoelectric accelerometer can be selectively prepared with best outcomes according to the requirements for the sensitivity and resonant frequency, fundamentally associated with trade-off relation.

scholarly journals Design Optimization of Bulk Piezoelectric Acceleration Sensor for Enhanced Performance

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3360 ◽  
Author(s):  
Min-Ku Lee ◽  
Seung-Ho Han ◽  
Kyu-Hyun Park ◽  
Jin-Ju Park ◽  
Whung-Whoe Kim ◽  
...  
Keyword(s):  
Resonant Frequency ◽  
Opposite Effect ◽  
Acceleration Sensor ◽  
Electric Voltage ◽  
Design Variables ◽  
Simulation Based ◽  
Inner Diameter ◽  
Design Characteristics ◽  
Positive Effect ◽  
Piezoelectric Acceleration

While seeking to achieve high performances of a bulk piezoelectric acceleration sensor, we investigated the behavior of the design variables of the sensor components and optimized the sensor design using a numerical simulation based on piezoelectric analysis and metamodeling. The optimized results demonstrated that there was an exponential dependency in the trade-off relation between two performance indicators, the electric voltage and the resonant frequency, as induced by the design characteristics of the sensor. Among the design variables, a decrease in the base height and epoxy thickness and an increase in the piezo element’s inner diameter had a positive effect on two performances, while the head dimensions (diameter and height) exhibited the opposite effect on them. The optimal sensor designs are proposed within the valid range of resonant frequency (25–47.5 kHz). Our redesign of a commercial reference sensor improved the resonant frequency by 13.2% and the electric voltage by 46.1%.

scholarly journals Career concerns versus shared values: An empirical investigation

2017 ◽  
Vol 31 (2) ◽  
pp. 162-184 ◽  
Author(s):  
Tom McKenzie ◽  
Alasdair C Rutherford
Keyword(s):  
United Kingdom ◽  
Career Paths ◽  
Empirical Investigation ◽  
Shared Values ◽  
Career Concerns ◽  
Trade Off ◽  
Employee Recruitment ◽  
The United Kingdom ◽  
Matched Data ◽  
The Relationship

We study the relationship between career concerns and shared values empirically using employee–employer matched data for the United Kingdom and overtime hours as a proxy for hard work. In line with standard career-concerns theory, we find that employees work less overtime the longer they have been with their current employer. We also find that employees who agree strongly with the statement ‘I share many of the values of my organisation’ do roughly 20% more overtime than the rest. Our results suggest the existence of a trade-off between career concerns and shared values. We begin to consider some potential implications of this for employee recruitment as well as for the design of career paths across the private, public and voluntary sectors.

scholarly journals Noni fruit’s water spot appearance on the second day of harvest: a trade-off between resistance and energy

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Tian Wu ◽  
Danyan Hu ◽  
Qingfen Wang
Keyword(s):  
Statistical Analysis ◽  
Molecular Level ◽  
Morinda Citrifolia ◽  
Transcriptome Data ◽  
Trade Off ◽  
Kegg Pathways ◽  
Available Energy ◽  
Climacteric Fruit ◽  
The Relationship ◽  
Insight Into

Abstract Background Noni (Morinda citrifolia Linn.) is a tropical tree that bears climacteric fruit. Previous observations and research have shown that the second day (2 d) after harvest is the most important demarcation point when the fruit has the same appearance as the freshly picked fruit (0 d); however, they are beginning to become water spot appearance. We performed a conjoint analysis of metabolome and transcriptome data for noni fruit of 0 d and 2 d to reveal what happened to the fruit at the molecular level. Genes and metabolites were annotated to KEGG pathways and the co-annotated KEGG pathways were used as a statistical analysis. Results We found 25 pathways that were significantly altered at both metabolic and transcriptional levels, including a total of 285 differentially expressed genes (DEGs) and 11 differential metabolites through an integrative analysis of transcriptomics and metabolomics. The energy metabolism and pathways originating from phenylalanine were disturbed the most. The upregulated resistance metabolites and genes implied the increase of resistance and energy consumption in the postharvest noni fruit. Most genes involved in glycolysis were downregulated, further limiting the available energy. This lack of energy led noni fruit to water spot appearance, a prelude to softening. The metabolites and genes related to the resistance and energy interacted and restricted each other to keep noni fruit seemingly hard within two days after harvest, but actually the softening was already unstoppable. Conclusions This study provides a new insight into the relationship between the metabolites and genes of noni fruit, as well as a foundation for further clarification of the post-ripening mechanism in noni fruit.

Relaxor Single Crystals with Giant k31 Mode

2006 ◽  
Vol 45 ◽  
pp. 2412-2421
Author(s):  
Toshio Ogawa
Keyword(s):  
Single Crystal ◽  
Electromechanical Coupling ◽  
Impedance Measurement ◽  
Hysteresis Loops ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Poling Direction ◽  
Length Direction ◽  
Relaxor Single Crystals ◽  
The Relationship

Giant electromechanical coupling factor of k31 mode over 86% was found for (100) Pb[(Zn1/3Nb2/3)0.91Ti0.09]O3 and (110) Pb[(Mg1/3Nb2/3)0.74Ti0.26]O3 single-crystal plates poled in the [100] and [110] directions, respectively. The P-E hysteresis loops in the single-crystal plates with giant k31 became asymmetric. Furthermore, the frequency response of impedance in these plates with giant k31 consisted of a single vibration in the length direction. A mechanism to realize giant k31 can be explained by the relationship between the crystal plane and poling direction. In addition, the existence of giant piezoelectric d31 constant was proven by the strain measurement as well as by the impedance measurement.

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