Input-dependent performance study of a nonlinear piezoelectric energy harvester

2016 ◽  
Vol 28 (5) ◽  
pp. 619-626 ◽  
Author(s):  
Wei Deng ◽  
Ya Wang
Keyword(s):  
Root Mean Square ◽  
Principal Components ◽  
Energy Harvester ◽  
Amplitude Ratio ◽  
Principal Component ◽  
Magnetic Interaction ◽  
Mean Square ◽  
Performance Study ◽  
Piezoelectric Energy ◽  
Voltage Output

This work reports an input-dependent performance study of a nonlinear piezoelectric energy harvester with introduced magnetic interaction. The performances of the novel harvester with two external magnet arrays (I and II) are compared. Array II that has symmetric magnetic force yields better voltage output under frequency sweep test. As such, the energy harvesting capacity with Array II is performed under two vibration inputs (I and II). Under excitation Input I with periodic varying frequency, experimental results show that the nonlinear piezoelectric harvester outperforms its linear counterpart (no magnetic interaction) at alternating input bandwidths. A 104.5% improvement of root mean square voltage output (318.2% of power output) is obtained under excitation of 0.334 g (root mean square) and bandwidth of 7 Hz. No advantage is observed under Input II consisting of one principal and finite non-principal components. However, detailed study indicates that the amplitude of the principal component and the amplitude ratio of the non-principal components to the principal component in Input II are essential to maintain large-amplitude periodic motion. Our work provides useful insights into the design, characterization, and application of nonlinear energy harvesters with external magnetic forces based on a priori knowledge of input.

Power Density Performance Improvements for High Pressure Ripple Energy Harvesting

2013 ◽  
Author(s):  
Nalin Verma ◽  
Kenneth A. Cunefare ◽  
Ellen Skow ◽  
Alper Erturk
Keyword(s):  
High Pressure ◽  
Root Mean Square ◽  
Power Output ◽  
Energy Harvester ◽  
Dynamic Pressure ◽  
Hydraulic Pressure ◽  
Pressure Amplitude ◽  
Mean Square ◽  
Pressure Ripple ◽  
Ripple Amplitude

A hydraulic pressure energy harvester (HPEH) device, which utilizes a housing to isolate a piezoelectric stack from the hydraulic fluid via a mechanical interface, generates power by converting the dynamic pressure within the system into electricity. Prior work developed an HPEH device capable of generating 2187 microWatts from an 85 kPa pressure ripple amplitude using a 1387 mm3 stack. A new generation of HPEH produced 157 microWatts at the test conditions of 18 MPa static pressure and 394 kPa root-mean-square pressure amplitude using a 50 mm3 stack, thus increasing the power produced per volume of piezoelectric stack principally due to the higher dynamic pressure input. The stack and housing design implemented on this new prototype device yield a compact, high-pressure hydraulic pressure energy harvester designed to withstand 35 MPa. The device, which is less than a 2.54 cm in length as compared to a 5.3 cm length of a previous HPEH, was statically tested up to 21.9 MPa and dynamically tested up to 19 MPa with 400 kPa root-mean-square dynamic pressure amplitude. An inductor was included in the load circuit in parallel with the stack and the load resistance to increase the power output of the device. A previously developed electromechanical power output model for this device that predicts the power output given the dynamic pressure ripple amplitude is compared to the power results. The power extracted from this device would be sufficient to meet the proposed applications of the device, which is to power sensor nodes in hydraulic systems.

scholarly journals Theoretical and Experimental Study of Nonlinear and Electro-Magneto-Mechanical-Based Piezoelectric Vibration Energy Harvester

2019 ◽  
Vol 2019 ◽  
pp. 1-17
Author(s):  
Shilong Sun ◽  
Xiao Zhang
Keyword(s):  
Experimental Study ◽  
Energy Harvester ◽  
Time History ◽  
Vibration Energy ◽  
Voltage Response ◽  
Vibration Energy Harvester ◽  
Piezoelectric Energy ◽  
Voltage Output ◽  
Cantilevered Beam ◽  
Substrate Plate

This paper presents a folded nonlinear electro-magneto-mechanical (EMM) vibration-based piezoelectric energy harvester system, which is built on the cantilevered beam structure and consists of one host beam and two substrate plates. The performance of the linearity and nonlinearity to the proposed EMM system is evaluated and compared. Moreover, the voltage response in time history and the phase portrait are studied under an external rectifier circuit with a resistor. The results show that the nonlinearity of the reported EMM system changes the coherent resonance vibration mode from single to double under a harmonic base excitation within the frequency range of 20 Hz–50 Hz. Meanwhile, the substrate plate D contributes more averaged voltage output at a lower frequency while the substrate plate A contributes the voltage output at the relatively higher frequency for the nonlinear EMM system. The experimental study indicates that the proposed nonlinear EMM vibration-based piezoelectric energy harvester can yield a total voltage of 8.133 [email protected] Hz while the baseline structure only produces 1.724 [email protected] Hz. In addition, the bandwidth range of high-power output is enlarged by the nonlinear EMM system, which makes this device more flexible and applicable to absorb the wasted vibration energy generated by industrial machines and public facilities.

scholarly journals Flexible piezoelectric energy harvester/sensor with high voltage output over wide temperature range

Nano Energy ◽  
2019 ◽  
Vol 61 ◽  
pp. 337-345 ◽  
Author(s):  
Yanhua Sun ◽  
Jianguo Chen ◽  
Xiaoning Li ◽  
Yun Lu ◽  
Shujun Zhang ◽  
...  
Keyword(s):  
High Voltage ◽  
Wide Temperature Range ◽  
Energy Harvester ◽  
Temperature Range ◽  
Piezoelectric Energy ◽  
Voltage Output

An Evaluation of the Psychometric Properties of the Sheehan Disability Scale in a Chinese Psychotherapy-Seeking Sample

2020 ◽  
Vol 34 (1) ◽  
pp. 58-69
Author(s):  
Kristina Zeljic ◽  
Yingying Zhang ◽  
Xian Qiu ◽  
Xi Chen ◽  
Hengfen Gong ◽  
...  
Keyword(s):  
Root Mean Square ◽  
Convergent Validity ◽  
Goodness Of Fit ◽  
Intraclass Correlation ◽  
Principal Component ◽  
Mean Square ◽  
Sheehan Disability Scale ◽  
Depression Anxiety Stress Scale ◽  
Disability Scale ◽  
Fit Index

Although the Sheehan Disability Scale (SDS) is one of the most extensively used and tested disability measurements, there has only been one psychometric evaluation of its properties in a Chinese-speaking population. Here, we provide a comprehensive psychometric assessment of the scale in 465 Mandarin-speakers who were accessing information online regarding psychotherapy. Principal component analysis and subsequent confirmatory factor analysis indicated that the SDS is one-dimensional (normed fit index = 0.976, non-normed fit index = 0.97, comparative fit index = 0.98, goodness-of-fit index = 0.967, standardized root mean-square residual = 0.023, root mean-square error of approximation = 0.149). The SDS exhibited excellent internal consistency (α = .89) and moderate test–retest reliability when readministered approximately 8 days later (intraclass correlation coefficient = 0.55). Convergent validity was demonstrated by strong relationships with other measures of functional impairment (FI), while divergent validity was evidenced by fair correlation with a treatment ambivalence measure. Known-groups validity analyses showed that high FI was associated with significantly higher clinical scores of anxiety, depression, and obsessive-compulsive symptoms. Regression analysis indicated that the Depression Anxiety Stress Scale-21 score accounted for 37.6% of variance in FI. Overall, these findings support the reliability and validity of the SDS when used in Chinese treatment-seeking individuals, as well its usefulness as an online screening tool of FI.

Application of Chemometrics for Spectral Resolving and Determination of Three Analgesics in Water Samples

2020 ◽  
Vol 103 (1) ◽  
pp. 257-264 ◽  
Author(s):  
Ali M Yehia ◽  
Heba T Elbalkiny ◽  
Safa’a M Riad ◽  
Yasser S Elsaharty
Keyword(s):  
Root Mean Square Error ◽  
Least Squares ◽  
Mean Square Error ◽  
Root Mean Square ◽  
Water Samples ◽  
Principal Component ◽  
Multivariate Curve Resolution ◽  
Mean Square ◽  
Qualitative And Quantitative

Abstract Background: Chemometrics is a discipline that allows the spectral resolution of drugs in a complicated matrix (e.g., environmental water samples) as an alternative to chromatographic methods. Objective: Three analgesics were traced in wastewater samples with simple and cost-effective multivariate approaches using spectrophotometric data. Methods and Results: Four chemometric approaches were applied for the simultaneous determination of diclofenac, paracetamol, and ibuprofen. Partial least squares (PLS), principal component regression (PCR), artificial neural networks (ANN), and multivariate curve resolution (MCR)–alternating least squares (ALS) were selected. The presented methods were compared and validated for their qualitative and quantitative analyses. Moreover, statistical comparison between the results obtained by the proposed methods and the official methods showed no significant differences. Conclusions: The proposed multivariate calibrations were accurate and specific for quantitative analysis of the studied components. MCR-ALS is the only method that has the capacity for both the quantitative and qualitative analysis of the studied drugs. Highlights: Four chemometric approaches were used for analysis of severally overlapped ternary mixture of three analgesics. The analytical performance of PCR, PLS, MCR-ALS, and ANN was compared and validated in terms of root mean square error of calibration (RMSEC), SE of prediction, and recoveries. ANN gave the highest predicted concentrations with the lowest RMSEC and root mean square error of prediction. MCR-ALS has the capacity for both qualitative and quantitative measurement. The methods have been effectively applied for real samples and compared to official methods.

Assessment of Pareto Calibration, Stability, and Wavelength Selection

2003 ◽  
Vol 57 (3) ◽  
pp. 309-316 ◽  
Author(s):  
Kelly J. Anderson ◽  
John H. Kalivas
Keyword(s):  
Root Mean Square Error ◽  
Mean Square Error ◽  
Root Mean Square ◽  
Principal Component Regression ◽  
Principal Component ◽  
Data Sets ◽  
Mean Square ◽  
Wavelength Selection ◽  
Pareto Model ◽  
Improve Analysis

Recent work has shown that ridge regression (RR) is Pareto to partial least squares (PLS) and principal component regression (PCR) when the variance indicator Euclidian norm of the regression coefficients, ‖p̂‖, is plotted against the bias indicator root mean square error of calibration (RMSEC). Simplex optimization demonstrates that RR is Pareto for several other spectral data sets when ‖p̂‖ is used with RMSEC and the root mean square error of evaluation (RMSEE) as optimization criteria. From this investigation, it was observed that while RR is Pareto optimal, PLS and PCR harmonious models are near equivalent to harmonious RR models. Additionally, it was found that RR is Pareto robust, i.e., models formed at one temperature were then used to predict samples at another temperature. Wavelength selection is commonly performed to improve analysis results such that bias indicators RMSEC, RMSEE, root mean square error of validation, or root mean square error of cross-validation decrease using a subset of wavelengths. Just as critical to an analysis of selected wavelengths is an assessment of variance. Using wavelengths deemed optimal in a previous study, this paper reports on the variance/bias tradeoff. An approach that forms the Pareto model with a Pareto wavelength subset is suggested.

scholarly journals Optimizing Community and Hospital Services Using the Cancer Support Source Program

2018 ◽  
Vol 7 (1) ◽  
pp. 96-104
Author(s):  
Emily J Ross ◽  
Chelsea H Wiener ◽  
Diane Robinson ◽  
Jeffrey E Cassisi
Keyword(s):  
Physical Health ◽  
Root Mean Square ◽  
Emotional Distress ◽  
Principal Component ◽  
Mean Square ◽  
Health Concerns ◽  
Root Mean Square Residual ◽  
Cancer Support ◽  
Resource Needs ◽  
Area Of Concern

Background: The Cancer Support Community developed the Cancer Support Source (CSS) to assess the needs of cancer patients with distress. Each item on this self-administered questionnaire represents an area of concern which the patient rates and indicates their need for action with a “staff person,” but no details about the category of staff is given. Objective: To examine the factor structure of the CSS and to increase its utility to triage patients for referral to services based on a needs assessment. Methods: Data from 690 patients who completed the CSS over a 1-year period were analyzed. In study 1, an exploratory principal component analysis was conducted. In study 2, the fit of this proposed model was evaluated with confirmatory factor analysis (CFA). Results: Three factors were retained in the final CFA: emotional distress, physical health concerns, and resource needs. This model demonstrated adequate fit, Root Mean Square Error of Approximation (RMSEA)= 0.056, Comparitive Fit Index (CFI) = .907, Standardized Root Mean Square Residual (SRMR) = 0.050. Conclusions: Three factors are proposed as CSS subscales to guide referral and coordinate services: Emotional Distress/Patient and Family Counselor, Physical Health Concerns/Medical Care Provider, and Resource Needs/Case Management-Clinical Social Worker. The clinical utility of these referral subscales should be established with additional research.

Magnetic Coupled Cantilever Piezoelectric Energy Harvester

2012 ◽  
Author(s):  
Lihua Tang ◽  
Yaowen Yang ◽  
Liya Zhao
Keyword(s):  
Energy Harvester ◽  
Magnetic Interaction ◽  
Experimental Tests ◽  
Governing Equations ◽  
Vibration Energy Harvester ◽  
Single Degree Of Freedom ◽  
Piezoelectric Energy ◽  
Lumped Parameter ◽  
Lumped Parameter Models ◽  
Operating Bandwidth

A conventional vibration energy harvester is usually designed as a linear single-degree-of-freedom (1DOF) resonator. The efforts to improve its efficiency involve two aspects, i.e., enlarging the magnitude of output and widening the operating bandwidth. In this paper, we propose a magnetic coupled cantilever piezoelectric energy harvester (PEH) to achieve the above two goals. Different from other reported magnetic coupled PEHs, the magnetic interaction in the proposed design is introduced by a magnetic oscillator. Firstly, the lumped parameter models are established for the conventional linear PEH, the nonlinear PEH with a fixed magnet and the proposed PEH with a magnetic oscillator. The governing equations of the three systems are then provided in the state space form and their dynamics can be simulated by numerical integration. Subsequently, experimental tests are performed to validate the models. Both experiment and simulation show that the dynamics of the magnetic oscillator is able to not only broaden the operating bandwidth but also enhance the maximum power output of the PEH. Based on the validated model, parametric study is conducted to optimize the system performance.

scholarly journals Development of a Non-Linear Bi-Directional Vortex-Induced Piezoelectric Energy Harvester with Magnetic Interaction

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2299
Author(s):  
Wei-Jiun Su ◽  
Zong-Siang Wang
Keyword(s):  
Magnetic Force ◽  
Energy Harvester ◽  
Beam Theory ◽  
Magnetic Interaction ◽  
Peak Voltage ◽  
Piezoelectric Energy ◽  
Vortex Induced Vibrations ◽  
Charge Model ◽  
Non Linear ◽  
Lock In

In this study, magnetic force is introduced to the design of a bi-directional U-shaped piezoelectric energy harvester for vortex-induced vibrations. The theoretical model of the beam structure is derived based on the Euler–Bernoulli beam theory. The vortex-induced vibration and the non-linear magnetic force are modeled according to the Rayleigh oscillator and the charge model, respectively. A prototype is fabricated and tested in two orthogonal directions under vortex-induced vibrations in a wind tunnel. Up and down wind-speed sweeps are carried out to investigate the non-linear responses of the harvester. The distance between the magnets and the length of the side beams are adjusted to examine the influence of the magnetic force on the lock-in region and voltage output of the harvester. Overall, the harvester shows strong non-linearity in the horizontal excitations. After adding magnets to the system, significant improvement of the lock-in region and the peak voltage is noticed in the horizontal mode under both up and down sweeps.

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