On the in-plane vibrations and electromechanical resonance characteristics of non-uniformly polarized rectangular piezoelectric wafers: selective mode-type excitation and specific mode enhancement

2021 ◽  
pp. 116129
Author(s):  
Vamshi Krishna Chillara ◽  
Christopher Hakoda ◽  
Cristian Pantea
Keyword(s):  
Specific Mode ◽  
Piezoelectric Wafers ◽  
Electromechanical Resonance

Dynamic modeling of a galloping structure equipped with piezoelectric wafers and energy harvesting

2019 ◽  
Vol 67 (3) ◽  
pp. 142-154 ◽  
Author(s):  
M. Y. Abdollahzadeh Jamalabadi ◽  
Moon K. Kwak
Keyword(s):  
Energy Harvesting ◽  
Cantilever Beam ◽  
Vibrational Energy ◽  
Virtual Work ◽  
Power Level ◽  
Closed Form Solutions ◽  
Multi Scale ◽  
Rigid Mass ◽  
Piezoelectric Wafer ◽  
Piezoelectric Wafers

This study presents the analytical solution and experimental investigation of the galloping energy harvesting from oscillating elastic cantilever beam with a rigid mass. A piezoelectric wafer was attached to galloping cantilever beam to harvest vibrational energy in electric charge form. Based on Euler-Bernoulli beam assumption and piezoelectric constitutive equation, kinetic energy and potential energy of system were obtained for the proposed structure. Virtual work by generated charge and galloping force applied onto the rigid mass was obtained based on Kirchhoff's law and quasistatic assumption. Nonlinear governing electro-mechanical equations were then obtained using Hamilton's principle. As the system vibrates by self-exciting force, the fundamental mode is the only one excited by galloping. Hence, multi-degreeof-freedom equation of motion is simplified to one-degree-of-freedom model. In this study, closed-form solutions for electro-mechanical equations were obtained by using multi-scale method. Using these solutions, we can predict galloping amplitude, voltage amplitude and harvested power level. Numerical and experimental results are presented and discrepancies between experimental and numerical results are fully discussed.

scholarly journals Design and Analysis of a Novel Piezoceramic Stack-based Smart Aggregate

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6438
Author(s):  
Guangtao Lu ◽  
Xin Zhu ◽  
Tao Wang ◽  
Zhiqiang Hao ◽  
Bohai Tan
Keyword(s):  
Resonance Frequency ◽  
Electromechanical Coupling ◽  
Structural Parameters ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Stress Waves ◽  
Parallel Connection ◽  
Smart Aggregate ◽  
In Series ◽  
Piezoelectric Wafers

A novel piezoceramic stack-based smart aggregate (PiSSA) with piezoceramic wafers in series or parallel connection is developed to increase the efficiency and output performance over the conventional smart aggregate with only one piezoelectric patch. Due to the improvement, PiSSA is suitable for situations where the stress waves easily attenuate. In PiSSA, the piezoelectric wafers are electrically connected in series or parallel, and three types of piezoelectric wafers with different electrode patterns are designed for easy connection. Based on the theory of piezo-elasticity, a simplified one-dimensional model is derived to study the electromechanical, transmitting and sensing performance of PiSSAs with the wafers in series and parallel connection, and the model was verified by experiments. The theoretical results reveal that the first resonance frequency of PiSSAs in series and parallel decreases as the number or thickness of the PZT wafers increases, and the first electromechanical coupling factor increases firstly and then decrease gradually as the number or thickness increases. The results also show that both the first resonance frequency and the first electromechanical coupling factor of PiSSA in series and parallel change no more than 0.87% as the Young’s modulus of the epoxy increases from 0.5 to 1.5 times 3.2 GPa, which is helpful for the fabrication of PiSSAs. In addition, the displacement output of PiSSAs in parallel is about 2.18–22.49 times that in series at 1–50 kHz, while the voltage output of PiSSAs in parallel is much less than that in parallel, which indicates that PiSSA in parallel is much more suitable for working as an actuator to excite stress waves and PiSSA in series is suitable for working as a sensor to detect the waves. All the results demonstrate that the connecting type, number and thickness of the PZT wafers should be carefully selected to increase the efficiency and output of PiSSA actuators and sensors. This study contributes to providing a method to investigate the characteristics and optimize the structural parameters of the proposed PiSSAs.

LAG-3 does not define a specific mode of natural killing in human

1998 ◽  
Vol 61 (2-3) ◽  
pp. 109-112 ◽  
Author(s):  
Bertrand Huard ◽  
Muriel Tournier ◽  
Frédéric Triebel
Keyword(s):  
Natural Killing ◽  
Specific Mode

A POST-LIBERAL ORDER? HANS ZEHRER AND CONSERVATIVE CONSENSUS BUILDING IN 1950S WEST GERMANY

2012 ◽  
Vol 9 (3) ◽  
pp. 681-698 ◽  
Author(s):  
MARCUS M. PAYK
Keyword(s):  
Federal Republic ◽  
Weimar Republic ◽  
Political System ◽  
West Germany ◽  
New Order ◽  
Consensus Building ◽  
Right Wing ◽  
Federal Republic Of Germany ◽  
Specific Mode ◽  
Sociopolitical Context

While it is well known that German conservative intellectuals were skeptical or indifferent to the Federal Republic of Germany established in 1949 and to its democratic founding principles, this essay shifts attention to a specific mode of right-wing acceptance of the new order. Focusing on Hans Zehrer, a renowned journalist and notorious opponent of democracy in the Weimar Republic, I will demonstrate how right-wing intellectuals interpreted West Germany's political system as a post-liberal order after the “end of politics”. But this vision of transcending societal and intellectual conflicts in a meta-politics was neither entirely new nor simply raked up from the late 1920s but reshaped to fit the postwar sociopolitical context. The essay illuminates several intellectual connections between Weimar-era neoconservatism and the specific conservative consensus formed after 1949, but it also explores personnel continuities within a network of right-wing journalists as well as continuities in the field of journalistic style.

Balancing of Values and the Value of Balancing (Part One)

2021 ◽  
pp. 13-24
Author(s):  
Gadis A. Gadzhiev ◽  
◽  
Elena A. Voinikanis ◽  
Keyword(s):  
Human Rights ◽  
Critical Issue ◽  
Specific Mode ◽  
Constitutional Order ◽  
Basic Law ◽  
The Relationship

The article discusses the specific mode of existence of values – balancing or op­timization when it comes to deontological values. The authors using examples of values such as the principles of law and human rights, the rules of balancing are analyzed, which, according to G. Hart's classification, are secondary norms. The critical issue for the legal balancing procedure is the relationship between legal reality and values as such. Are the constitutional and legal values set by the Basic Law (Constitution), or do they objectively exist in society as a general (pre-constitutional) order of values? Should the Basic Law be confined to its own text and remain value-neutral in this sense? Are legal values purely deonto­logical, or can they be related to utilitarian goals and interests? The second part of the article explores the value of balancing as one of the methods for resolving the most complex legal conflicts. The well-known dispute between J. Habermas and R. Alexy about the admissibility of balancing of human rights demonstrates how complex and philosophically rich the legal balancing procedure is. Based on Luhmann’s concept of the cognitive openness of law, at the end of the article, the authors substantiate their own position on the role of values in modern justice.

scholarly journals Shanghai Alleys, Theatrical Practice, and Cinematic Spectatorship: FromStreet Angel(1937) to Fifth Generation Film

2010 ◽  
Vol 39 (4) ◽  
pp. 29-51 ◽  
Author(s):  
Alexander Des Forges
Keyword(s):  
Urban Environment ◽  
Spatial Organization ◽  
Political Action ◽  
Specific Mode ◽  
Republican Period ◽  
Fifth Generation ◽  
Theatrical Practice ◽  
The City

This article argues that a certain type of Shanghai film of the Republican period, exemplified by 1937's Street Angel ([Formula: see text], Malu tianshi), makes use of a specific mode of spatial organization, modelled on the theatre, to represent the urban environment. In the case of Street Angel, and later on in 1964's Stage Sisters ([Formula: see text], Wutai jiemei), the interaction between performers and audiences characteristic of the Shanghai theatre experience serves as a crucial ground on which to base calls to political action. For a variety of related reasons, both the city of Shanghai and this mode of spatial organization so closely associated with it vanish from the big screen in the 1980s and 1990s, and begin to make a return only at the turn of the new century.

scholarly journals Designing Research With Qualitative Comparative Analysis (QCA): Approaches, Challenges, and Tools

2017 ◽  
Vol 49 (2) ◽  
pp. 356-386 ◽  
Author(s):  
Eva Thomann ◽  
Martino Maggetti
Keyword(s):  
Comparative Analysis ◽  
External Validity ◽  
Qualitative Comparative Analysis ◽  
Internal Validity ◽  
Specific Research ◽  
Extant Literature ◽  
Specific Mode ◽  
Research Context ◽  
Trade Offs ◽  
Conducting Research

Recent years have witnessed a host of innovations for conducting research with qualitative comparative analysis (QCA). Concurrently, important issues surrounding its uses have been highlighted. In this article, we seek to help users design QCA studies. We argue that establishing inference with QCA involves three intertwined design components: first, clarifying the question of external validity; second, ensuring internal validity; and third, explicitly adopting a specific mode of reasoning. We identify several emerging approaches to QCA rather than just one. Some approaches emphasize case knowledge, while others are condition oriented. Approaches emphasize either substantively interpretable or redundancy-free explanations, and some designs apply an inductive/explorative mode of reasoning, while others integrate deductive elements. Based on extant literature, we discuss issues surrounding inference with QCA and the tools available under different approaches to address these issues. We specify trade-offs and the importance of doing justice to the nature and goals of QCA in a specific research context.

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