Nonlinear Dynamics of Nonlinear L-Shape Piezoelectric Systems for Positive and Reverse Sweep Waveform

2019 ◽  
Author(s):  
Ming Hui Yao
Keyword(s):  
Power Generation ◽  
Piezoelectric Layer ◽  
Great Influence ◽  
Experimental Results ◽  
Beam Power ◽  
Dynamic Behaviors ◽  
Piezoelectric Beam ◽  
Stiffness Characteristic ◽  
Generation Structure ◽  
The Relationship

Abstract This paper presents a bistable inverted L-shaped piezoelectric beam power generation structure, and its dynamic behaviors and power generation performance are studied by positive and reverse sweep waveform experiments. The piezoelectric beam includes the substructure layer and the piezoelectric layer. The material of the piezoelectric layer is the piezoelectric ceramic transducer (PZT), and the material of the substructure layer is the phosphor brass. The positive and reverse sinusoidal excitation signal is selected. The snap through phenomenon and stiffness characteristic of the system are investigated by experimental results of the positive and reverse sweep waveform. The relationship between dynamic behaviors and electrical behaviors of the system is also studied. Experimental results show that the positive and reverse sweep waveform has a great influence on vibration of the nonlinear system. Due to the hard spring characteristic of the system, the large vibration amplitude is easy to appear in the positive sweep waveform. Dynamic behaviors of the piezoelectric system are related to its electrical behaviors. When dynamic behaviors bifurcate, electrical behaviors bifurcate. These results can be applied to explore the vibration characteristic and the power generation of the nonlinear piezoelectric system.

Research on the Color Performance Changes of iPad Affected by Brightness Settings

2014 ◽  
Vol 513-517 ◽  
pp. 4319-4322 ◽  
Author(s):  
Jian Qing Zhang ◽  
Zhen Liu ◽  
Liang Lu ◽  
Hai Qi Yu ◽  
Xi Zhang
Keyword(s):  
Great Influence ◽  
Experimental Results ◽  
Coverage Ratio ◽  
Color Characteristics ◽  
The Relationship

The relationship was derived between the brightness setting and the corresponding color characteristics of the new pad display. Chromaticity domain coverage ratio , channel additivity and the constant channel chromaticity under difference brightness values were measured and compared in detail. The experimental results showed that brightness settings had a great influence on channel additivity, Chromaticity gamut coverage and the constant channel chromaticity meanwhile stable Chromaticity gamut coverage and good channel additivity and the constant channel chromaticity, respectively corresponding to different brightness range . conclusion: When brightness was setted in the range of 200cd/m2 ~ 353 cd/m2 , the new pad had better color performance and more stable.

scholarly journals Nonlinear Dynamics and Power Generation on a New Bistable Piezoelectric-Electromagnetic Energy Harvester

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-29
Author(s):  
Minghui Yao ◽  
Pengfei Liu ◽  
Hongbo Wang
Keyword(s):  
Power Generation ◽  
Cantilever Beam ◽  
Energy Harvester ◽  
Electromagnetic Energy ◽  
Generation Efficiency ◽  
Dynamic Behaviors ◽  
Optimal Load ◽  
Piezoelectric Cantilever ◽  
Generation Structure ◽  
Electromagnetic Harvester

This paper focuses power generation and nonlinear dynamic behaviors on a new bistable piezoelectric-electromagnetic energy harvester. Three different kinds of piezoelectric cantilever beam structures, which include the monostable piezoelectric cantilever beam, the bistable piezoelectric cantilever beam with spring and magnet, and the bistable piezoelectric cantilever beam with spring, magnet, and coil, are designed. The power generation efficiency and dynamic behaviors for each structure are experimentally studied, respectively. Due to the spring introduced, the system easily goes through the potential barrier. Experimental results show that the power generation structure of the bistable piezoelectric-electromagnetic harvester can vibrate between two steady states in a wider range of the frequency. Therefore, the effective frequency bandwidth is broadened about 2 Hz when the spring is introduced under the condition of the suitable magnetic distance. Comparing with the power generation efficiency for three different kinds of structures, it is found that the bistable piezoelectric-electromagnetic harvester has the optimum characteristics, which include the optimal magnetic distance of 15 mm, the optimal load of 8 MΩ, and the parameters variation law of coils. For this structure, the influences of the external excitation and the magnetic distance on the output voltage and dynamic behaviors of the system are examined.

Parasites and promiscuity: Acute disease salience leads to more restricted sexual attitudes

2021 ◽  
pp. 026540752110309
Author(s):  
James B. Moran ◽  
Nicholas Kerry ◽  
Jin X. Goh ◽  
Damian R. Murray
Keyword(s):  
Social Behavior ◽  
Sexual Attitudes ◽  
Experimental Manipulation ◽  
Sexual Relationships ◽  
Experimental Results ◽  
Acute Disease ◽  
Short Term ◽  
Attitudes And Behaviors ◽  
The Relationship ◽  
Sexual Promiscuity

How does disease threat influence sexual attitudes and behaviors? Although research on the influence of disease threat on social behavior has grown considerably, the relationship between perceived disease threat and sexual attitudes remains unclear. The current preregistered study (analyzed N = 510), investigated how experimental reminders of disease threat influence attitudes and anticipated future behaviors pertaining to short-term sexual relationships, using an ecologically valid disease prime. The central preregistered prediction was that experimental manipulation of disease threat would lead to less favorable attitudes and inclinations toward sexual promiscuity. Results were consistent with this preregistered prediction, relative to both a neutral control condition and a non-disease threat condition. These experimental results were buttressed by the finding that dispositional variation in worry about disease threat predicted less favorable attitudes and inclinations toward short-term sexual relationships. This study represents the first preregistered investigation of the implications of acute disease threat for sexual attitudes.

Wave Energy Hyperbaric Device for Electricity Production

2007 ◽  
Author(s):  
Segen F. Estefen ◽  
Paulo Roberto da Costa ◽  
Eliab Ricarte ◽  
Marcelo M. Pinheiro
Keyword(s):  
Power Generation ◽  
Wave Energy ◽  
Experimental Results ◽  
Electricity Production ◽  
Scale Model ◽  
Small Scale ◽  
Regular Waves ◽  
Hyperbaric Chamber ◽  
Small Scale Model

Wave energy is a renewable and non-polluting source and its use is being studied in different countries. The paper presents an overview on the harnessing of energy from waves and the activities associated with setting up a plant for extracting energy from waves in Port of Pecem, on the coast of Ceara State, Brazil. The technology employed is based on storing water under pressure in a hyperbaric chamber, from which a controlled jet of water drives a standard turbine. The wave resource at the proposed location is presented in terms of statistics data obtained from previous monitoring. The device components are described and small scale model tested under regular waves representatives of the installation region. Based on the experimental results values of prescribed pressures are identified in order to optimize the power generation.

Research on Paper Whiteness Based on Visual Comfort

2013 ◽  
Vol 295-298 ◽  
pp. 543-546
Author(s):  
Zhi Jian Li ◽  
Nuo Li
Keyword(s):  
Negative Impact ◽  
Experimental Results ◽  
Reading Process ◽  
Visual Comfort ◽  
Visual Fatigue ◽  
The Relationship

High whiteness paper is likely to cause visual fatigue. The relationship between whiteness and visual comfort is studyed by adopting the form of a combination of presentation reading and questionnaires. The experimental results show that, during the reading process, the higher of paper whiteness, the greater the chance of looked up, eye rubbing, and other little tricks, at the same time, the easier inattentive, have a negative impact on reading effect.

scholarly journals Characterization of percolation behavior in conductor–dielectric 0-3 composites

2014 ◽  
Vol 04 (04) ◽  
pp. 1450035 ◽  
Author(s):  
Lin Zhang ◽  
Patrick Bass ◽  
Zhi-Min Dang ◽  
Z.-Y. Cheng
Keyword(s):  
Dielectric Constant ◽  
Percolation Threshold ◽  
Frequency Dependence ◽  
Experimental Results ◽  
Effective Dielectric Constant ◽  
Filler Concentration ◽  
Percolation Behavior ◽  
The Matrix ◽  
The Relationship

The equation ε eff ∝ (ϕc - ϕ)-s which shows the relationship between effective dielectric constant (εeff) and the filler concentration (φ), is widely used to determine the percolation behavior and obtain parameters, such as percolation threshold φc and the power constant s in conductor–dielectric composites (CDCs). Six different systems of CDCs were used to check the expression by fitting experimental results. It is found that the equation can fit the experimental results at any frequency. However, it is found that the fitting constants do not reflect the real percolation behavior of the composites. It is found that the dielectric constant is strongly dependent on the frequency, which is mainly due to the fact that the frequency dependence of the dielectric constant for the composites close to φc is almost independent of the matrix.

Face Recognition Algorithm Based on Kernel Collaborative Representation

2013 ◽  
Vol 756-759 ◽  
pp. 3590-3595
Author(s):  
Liang Zhang ◽  
Ji Wen Dong
Keyword(s):  
Face Recognition ◽  
Principal Components Analysis ◽  
Principal Components ◽  
Recognition Algorithm ◽  
Experimental Results ◽  
Collaborative Representation ◽  
Nonlinear Structures ◽  
Components Analysis ◽  
Kernel Principal Components Analysis ◽  
The Relationship

Aiming at solving the problems of occlusion and illumination in face recognition, a new method of face recognition based on Kernel Principal Components Analysis (KPCA) and Collaborative Representation Classifier (CRC) is developed. The KPCA can obtain effective discriminative information and reduce the feature dimensions by extracting faces nonlinear structures features, the decisive factor. Considering the collaboration among the samples, the CRC which synthetically consider the relationship among samples is used. Experimental results demonstrate that the algorithm obtains good recognition rates and also improves the efficiency. The KCRC algorithm can effectively solve the problem of illumination and occlusion in face recognition.

scholarly journals Photoreduction of Cr(VI) Ions in Aqueous Solutions by UV/ Photocatalytic Processes

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Chih Ming Ma ◽  
Yung Shuen Shen ◽  
Po Hsiang Lin
Keyword(s):  
Aqueous Solutions ◽  
Reaction Rate ◽  
Removal Rate ◽  
Experimental Results ◽  
Order Kinetic ◽  
Solution Ph ◽  
Relationship Of ◽  
The Relationship ◽  
Photocatalytic Processes ◽  
Order Kinetic Equation

This study discussed the photoreduction of Cr(VI) ions in aqueous solutions by UV/TiO2photocatalytic processes under various operational factors. Experimental results showed that the removal rate of Cr(VI) increased with decreasing solution pH values and with increasing dosages of organic compounds, indicating that the recombination rate of electrons and h+can be retarded in the reaction systems by the addition of the scavenger, thus raising the reaction rate of Cr(VI). The relationship of the chemical reaction rate of Cr(VI), TiO2dosage, and changes of Cr(VI) concentration was expressed by the pseudo-first-order kinetic equation. Comparing the experimental results of two different doping metals in modified TiO2photoreduction systems, the removal rate of Cr(VI) by the Ag/TiO2process is larger, possibly because the electron transferring ability of Ag is superior to that of Cu. However, the photoreduction rates of Cr(VI) by modified UV/TiO2processes are worse than those by a nonmodified commercial UV/TiO2process.

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