Piezoelectric T-Matrix Development and Multiple Scattering Analysis of Electroacoustic Wave Propagation in Thin Plates

2017 ◽  
Author(s):  
Amir Darabi ◽  
Michael Leamy
Keyword(s):  
Multiple Scattering ◽  
Wave Energy ◽  
Research Direction ◽  
Thin Plates ◽  
Matrix Formulation ◽  
Reflected Waves ◽  
Piezoelectric Patch ◽  
Electroacoustic Wave ◽  
T Matrix ◽  
New Research

Harvesting of acoustoelastic wave energy in thin plates and other structures is a promising new research direction for scavenging energy to power small sensors and devices. In particular, metamaterial-inspired harvesting concepts have shown strong potential for enhancing harvesting of acoustoelastic wave energy. In support of continued development of these metamaterial-based concepts, this paper presents a fully-coupled T-matrix formulation for assessing scattering of incident wave energy from a piezoelectric patch attached to a thin plate. The T-matrix serves as an input-output relationship between incident and reflected waves, and is developed herein for a piezoelectric patch connected to an external circuit. The utility of the T-matrix is evident in problems with multiple piezoelectric harvesters, where it can be used with other T-matrices (such as those previously formulated for rigid, void, and elastic inclusions) in a multiple scattering context. This has the potential for many uses in predicting the dynamic response of smart and active structures, but may be particularly useful in accurately assessing metamaterial-based energy harvesting enhancement strategies. Following development of the requisite T-matrix, harvesting in an example Gradient-Index (GRIN) metamaterial structure is predicted using the multiple scattering approach.

Multiple Scattering of Acoustoelastic Waves in Thin Plates for Enhanced Energy Harvesting

2016 ◽  
Author(s):  
Amir Darabi ◽  
Michael Leamy
Keyword(s):  
Energy Harvesting ◽  
Multiple Scattering ◽  
Wave Energy ◽  
Focal Point ◽  
Mechanical Energy ◽  
Single Point ◽  
Infinite Plate ◽  
Electrical Circuit ◽  
Thin Plates ◽  
Optimization Study

Harvesting of acoustoelastic wave energy in thin plates and other structures has recently gained attention from the energy harvesting community. To enhance the wave power generated, researchers have investigated metamaterial-inspired concepts to include funnels, mirrors, and defect-based resonators introduced in the metamaterial’s bandgap. Many of these concepts have been demonstrated experimentally using arrangements of cylindrical stubs mounted on the surface of a thin plate, where such stubs scatter plane and cylindrical waves in such a way as to focus mechanical energy. To support these studies, the authors have recently introduced an experimentally-verified analytical framework for investigating the coupled electromechanical response of a single circular piezoelectric harvester adhered to an infinite plate and excited by a distant harmonic point source. This paper extends these ideas to consider a similar physical system with the addition of multiple cylindrical inclusions. These additions require development of an electromechanically-coupled, multiple scattering formulation of significantly increased complexity. The formulation also includes an electrical circuit model for generating electrical current from incident waves interacting with the piezoelectric domain. Following development, the formulation is applied to the determination of optimal arrangements of scatterers which maximize the electrical power generated. Specifically, an optimization study is carried-out in which twenty-five scatterers are first placed in a semi-elliptical arrangement with the aim of focusing wave energy from one elliptical focus (i.e., source location) onto the other. It is known from past studies that additional side lobes are generated due to truncation of the ellipse, and thus not all of the energy can be focused at single point, as desired. To improve upon this situation, an optimization study is performed in which the aspect ratio of the ellipse is varied, with the goal of optimizing the power harvested from the focal point. Results from the optimization studies show conclusively that the side lobes can in fact be minimized, and that harvested power can be significantly improved.

Multiple Scattering of Flexural Waves on Thin Plates

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Liang-Wu Cai ◽  
Stephen A. Hambric
Keyword(s):  
Multiple Scattering ◽  
Cross Section ◽  
Scattering Amplitude ◽  
Thin Plates ◽  
Flexural Waves ◽  
Gap Formation ◽  
Numerical Examples ◽  
Different Types ◽  
Generalized Matrix ◽  
T Matrix

In this paper, the scattering of flexural waves on a thin Kirchhoff plate by an ensemble of through-thickness circular scatterers is formulated by using the concept of the T-matrix in a generalized matrix notation, with a focus on deterministic numerical computations. T-matrices for common types of scatterers, including the void (hole), rigid, and elastic scatterers, are obtained. Wave field properties in the multiple-scattering setting, such as the scattering amplitude, and scattering cross section, as well as properties of the T-matrix due to the energy conservation are discussed. After an extensive validation, numerical examples are used to explore the band gap formation due to different types of scatterers. One of the interesting observations is that a type of inclusion commonly referred to as the “rigid inclusion” in fact represents a clamped boundary that is closer to a riveted confinement than a rigid scatterer; and an array of such scatterers can block the wave transmission at virtually all frequencies.

A Robust Blind Image Forensic-Detection Method based on Fuzzy Technique

2019 ◽  
Vol 8 (3) ◽  
pp. 5926-5929
Keyword(s):  
Research Direction ◽  
Geometric Transformation ◽  
Detection Accuracy ◽  
Forensic Investigation ◽  
Image Forensic ◽  
Fuzzy Logic Approach ◽  
Logic Approach ◽  
Tampered Image ◽  
New Research ◽  
Blind Image

Blind forensic-investigation in a digital image is a new research direction in image security. It aims to discover the altered image content without any embedded security scheme. Block and key point based methods are the two dispensation options in blind image forensic investigation. Both the techniques exhibit the best performance to reveal the tampered image. The success of these methods is limited due to computational complexity and detection accuracy against various image distortions and geometric transformation operations. This article introduces different blind image tampering methods and introduces a robust image forensic investigation method to determine the copy-move tampered image by means of fuzzy logic approach. Empirical outcomes facilitate that the projected scheme effectively classifies copy-move type of forensic images as well as blurred tampered image. Overall detection accuracy of this method is high over the existing methods.

scholarly journals Advances in the role of miRNAs in the occurrence and development of osteosarcoma

Open Medicine ◽  
2020 ◽  
Vol 15 (1) ◽  
pp. 1003-1011
Author(s):  
Guanyu Zhang ◽  
Yiran Li ◽  
Jiasheng Xu ◽  
Zhenfang Xiong
Keyword(s):  
Target Gene ◽  
Early Stage ◽  
Research Direction ◽  
Research Progress ◽  
Skeletal System ◽  
Translation Process ◽  
Non Coding Rnas ◽  
New Research ◽  
Post Transcriptional Regulation

AbstractOsteosarcoma (OS) is the most common primary malignant tumor of the skeletal system in the clinic. It mainly occurs in adolescent patients and the pathogenesis of the disease is very complicated. The distant metastasis may occur in the early stage, and the prognosis is poor. MicroRNAs (miRNAs) are non-coding RNAs of about 18–25 nt in length that are involved in post-transcriptional regulation of genes. miRNAs can regulate target gene expression by promoting the degradation of target mRNAs or inhibiting the translation process, thereby the proliferation of OS cells can be inhibited and the apoptosis can be promoted; in this way, miRNAs can affect the metabolism of OS cells and can also participate in the occurrence, invasion, metastasis, and recurrence of OS. Some miRNAs have already been found to be closely related to the prognosis of patients with OS. Unlike other reviews, this review summarizes the miRNA molecules closely related to the development, diagnosis, prognosis, and treatment of OS in recent years. The expression and influence of miRNA molecule on OS were discussed in detail, and the related research progress was summarized to provide a new research direction for early diagnosis and treatment of OS.

scholarly journals A Phononic Crystal with Differently Configured Double Defects for Broadband Elastic Wave Energy Localization and Harvesting

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 643
Author(s):  
Soo-Ho Jo ◽  
Byeng D. Youn
Keyword(s):  
Elastic Wave ◽  
Wave Energy ◽  
Phononic Crystal ◽  
Square Lattice ◽  
Energy Localization ◽  
Piezoelectric Patch ◽  
Single Defect ◽  
Piezoelectric Energy ◽  
Piezoelectric Effects ◽  
Elastic Wave Energy

Several previous studies have been dedicated to incorporating double defect modes of a phononic crystal (PnC) into piezoelectric energy harvesting (PEH) systems to broaden the bandwidth. However, these prior studies are limited to examining an identical configuration of the double defects. Therefore, this paper aims to propose a new design concept for PnCs that examines differently configured double defects for broadband elastic wave energy localization and harvesting. For example, a square-pillar-type unit cell is considered and a defect is considered to be a structure where one piezoelectric patch is bonded to a host square lattice in the absence of a pillar. When the double defects introduced in a PnC are sufficiently distant from each other to implement decoupling behaviors, each defect oscillates like a single independent defect. Here, by differentiating the geometric dimensions of two piezoelectric patches, the defects’ dissimilar equivalent inertia and stiffness contribute to individually manipulating defect bands that correspond to each defect. Hence, with adequately designed piezoelectric patches that consider both the piezoelectric effects on shift patterns of defect bands and the characteristics for the output electric power obtained from a single-defect case, we can successfully localize and harvest the elastic wave energy transferred in broadband frequencies.

Lab Scale Study on Synergistic Disinfection of WWTPS Secondary Effluent by Ultrasonic and Ozone

2012 ◽  
Vol 433-440 ◽  
pp. 4751-4756 ◽  
Author(s):  
Hao Wu ◽  
Zi Fu Li ◽  
Xin Jin ◽  
Xin Zhao ◽  
Fu Rong Deng
Keyword(s):  
Reaction Time ◽  
Removal Rate ◽  
Research Direction ◽  
Synergistic Action ◽  
Color Removal ◽  
Secondary Effluent ◽  
Disinfection Methods ◽  
Number Of Microorganisms ◽  
New Research ◽  
Ozone Disinfection

Secondary effluent from WWTPS still contains a large number of microorganisms, therefore, disinfection is essential. There are many disadvantages in using traditional disinfection methods, so the combination of disinfection techniques is a new research direction. Ozone combined with ultrasound is one of them. In this experiment, the inactivation of the total coli forms, color removal and UV254 removal of secondary effluent by a combination of ultrasonic (frequency20 kHz; power100W) and ozone disinfection was investigated. The results show that the effect of the synergistic action of 30s US and ozone disinfection is superior to the effect of individual ozone disinfection. After 15min synergistic disinfection, the total coli forms inactivation rate is up to 99.9%, simultaneously color removal rate to 80% and UV254 removal rate to 52%. Compared with individual ozone disinfection, reaction time was reduced by 5 min.

A Data Mining Approach to Forming Generic Bills of Materials in Support of Variant Design Activities

2004 ◽  
Vol 4 (4) ◽  
pp. 316-328 ◽  
Author(s):  
Carol J. Romanowski , ◽  
Rakesh Nagi
Keyword(s):  
Data Mining ◽  
Product Family ◽  
Research Direction ◽  
Design Constraints ◽  
Variant Design ◽  
Data Mining Approach ◽  
Design Activities ◽  
Using Data ◽  
New Research

In variant design, the proliferation of bills of materials makes it difficult for designers to find previous designs that would aid in completing a new design task. This research presents a novel, data mining approach to forming generic bills of materials (GBOMs), entities that represent the different variants in a product family and facilitate the search for similar designs and configuration of new variants. The technical difficulties include: (i) developing families or categories for products, assemblies, and component parts; (ii) generalizing purchased parts and quantifying their similarity; (iii) performing tree union; and (iv) establishing design constraints. These challenges are met through data mining methods such as text and tree mining, a new tree union procedure, and embodying the GBOM and design constraints in constrained XML. The paper concludes with a case study, using data from a manufacturer of nurse call devices, and identifies a new research direction for data mining motivated by the domains of engineering design and information.

Vietnamese Proverbs From a Cultural Perspective

2019 ◽  
Author(s):  
Thanh Quy Ngo Thi ◽  
◽  
Hong Minh Nguyen Thi ◽  
Keyword(s):  
Cultural Values ◽  
Language Use ◽  
Interdisciplinary Approach ◽  
Research Direction ◽  
Point Of View ◽  
Traditional Values ◽  
Cultural Perspective ◽  
Language And Culture ◽  
Speakers Of Other Languages ◽  
New Research

Proverbs are important data depicting the traditional culture of each nation. Vietnamese proverbs, dated thousands of years ago, are an immense valuable treasure of experience which the Vietnamese people desire to pass to the younger generations. This paper aims to explore the unique and diversified world of intelligence and spirits of the Vietnamese through a condensed and special literary genre, as well as a traditional value of the nation (Nguyen Xuan Kinh 2013, Tran Ngoc Them 1996, Le Chi Que and Ngo Thi Thanh Quy 2014). Through an interdisciplinary approach, from an anthropological point of view, approaching proverbs we will open up a vast treasure of knowledge and culture of all Vietnamese generations. The study has examined over 16,000 Vietnamese proverbs and analysed three groups expressing Vietnamese people’s behaviors toward nature, society and their selves, and compared them with English and Japanese proverbs. The research has attempted to explore the beauty of Vietnamese language, cultural values and the souls and personalities of Vietnam. Approaching Vietnamese proverbs under the interdisciplinary perspective of language, culture and literature is a new research direction in the field of Social Sciences and Humanity in Vietnam. From these viewpoints, it is seen that proverbs have remarkably contributed to the language and culture of Vietnam as well as and constructed to the practice of language use in everyday life which is imaginary, meaningful and effective in communication. Furthermore, the study seeks to inspire the Vietnamese youth’s pride in national identity and to encourage their preservation and promotion for traditional values of the nation in the context of integration and globalisation. In the meantime, it would be favourable to introduce and market the beauty of Vietnamese language, culture and people to the world, encouraging the speakers of other languages to study, explore and understand Vietnam.

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