scholarly journals A Review of Acoustic Impedance Matching Techniques for Piezoelectric Sensors and Transducers

Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 4051 ◽  
Author(s):  
Vivek T. Rathod
Keyword(s):  
Acoustic Impedance ◽  
Signal To Noise Ratio ◽  
Impedance Matching ◽  
Acoustic Properties ◽  
Piezoelectric Sensors ◽  
Advantages And Disadvantages ◽  
The Difference ◽  
Matching Techniques ◽  
Passive Materials ◽  
Propagation Media

The coupling of waves between the piezoelectric generators, detectors, and propagating media is challenging due to mismatch in the acoustic properties. The mismatch leads to the reverberation of waves within the transducer, heating, low signal-to-noise ratio, and signal distortion. Acoustic impedance matching increases the coupling largely. This article presents standard methods to match the acoustic impedance of the piezoelectric sensors, actuators, and transducers with the surrounding wave propagation media. Acoustic matching methods utilizing active and passive materials have been discussed. Special materials such as nanocomposites, metamaterials, and metasurfaces as emerging materials have been presented. Emphasis is placed throughout the article to differentiate the difference between electric and acoustic impedance matching and the relation between the two. Comparison of various techniques is made with the discussion on capabilities, advantages, and disadvantages. Acoustic impedance matching for specific and uncommon applications has also been covered.

scholarly journals A Review of Electric Impedance Matching Techniques for Piezoelectric Sensors, Actuators and Transducers

Electronics ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 169 ◽  
Author(s):  
Vivek T. Rathod
Keyword(s):  
Transmission Lines ◽  
Power Supply ◽  
Electrical Impedance ◽  
Impedance Matching ◽  
Careful Consideration ◽  
Piezoelectric Sensors ◽  
Electric Signal ◽  
Electric Impedance ◽  
The Common ◽  
Matching Techniques

Any electric transmission lines involving the transfer of power or electric signal requires the matching of electric parameters with the driver, source, cable, or the receiver electronics. Proceeding with the design of electric impedance matching circuit for piezoelectric sensors, actuators, and transducers require careful consideration of the frequencies of operation, transmitter or receiver impedance, power supply or driver impedance and the impedance of the receiver electronics. This paper reviews the techniques available for matching the electric impedance of piezoelectric sensors, actuators, and transducers with their accessories like amplifiers, cables, power supply, receiver electronics and power storage. The techniques related to the design of power supply, preamplifier, cable, matching circuits for electric impedance matching with sensors, actuators, and transducers have been presented. The paper begins with the common tools, models, and material properties used for the design of electric impedance matching. Common analytical and numerical methods used to develop electric impedance matching networks have been reviewed. The role and importance of electrical impedance matching on the overall performance of the transducer system have been emphasized throughout. The paper reviews the common methods and new methods reported for electrical impedance matching for specific applications. The paper concludes with special applications and future perspectives considering the recent advancements in materials and electronics.

Microencapsulation and Nanoencapsulation: A Review

2017 ◽  
Vol 9 (3) ◽  
Author(s):  
V. Suganya ◽  
V. Anuradha
Keyword(s):  
Drug Release ◽  
New Technology ◽  
Inert Material ◽  
Food Industries ◽  
Control Drug ◽  
Advantages And Disadvantages ◽  
Nano Scale ◽  
Pharmaceutical Industries ◽  
The Difference ◽  
Control Drug Release

Encapsulation is a process of enclosing the substances within an inert material which protects from environment as well as control drug release. Recently, two type of encapsulation has been performed in several research. Nanoencapsulation is the coating of various substances within another material at sizes on the nano scale. Microencapsulation is similar to nanoencapsulation aside from it involving larger particles and having been done for a greater period of time than nanoencapsulation. Encapsulation is a new technology that has wide applications in pharmaceutical industries, agrochemical, food industries and cosmetics. In this review, the difference between micro and nano encapsulation has been explained. This article gives an overview of different methods and reason for encapsulation. The advantages and disadvantages of micro and nano encapsulation technology were also clearly mentioned in this paper.

scholarly journals Suppress Vibration on Robotic Polishing with Impedance Matching

Actuators ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 59
Author(s):  
Junjie Dai ◽  
Chin-Yin Chen ◽  
Renfeng Zhu ◽  
Guilin Yang ◽  
Chongchong Wang ◽  
...  
Keyword(s):  
Contact Force ◽  
Force Control ◽  
Impedance Control ◽  
Impedance Matching ◽  
Industrial Robots ◽  
Contact Phase ◽  
Dynamic Tracking ◽  
Force Tracking ◽  
The Difference ◽  
End Effectors

Installing force-controlled end-effectors on the end of industrial robots has become the mainstream method for robot force control. Additionally, during the polishing process, contact force stability has an important impact on polishing quality. However, due to the difference between the robot structure and the force-controlled end-effector, in the polishing operation, direct force control will have impact during the transition from noncontact to contact between the tool and the workpiece. Although impedance control can solve this problem, industrial robots still produce vibrations with high inertia and low stiffness. Therefore, this research proposes an impedance matching control strategy based on traditional direct force control and impedance control methods to improve this problem. This method’s primary purpose is to avoid force vibration in the contact phase and maintain force–tracking performance during the dynamic tracking phase. Simulation and experimental results show that this method can smoothly track the contact force and reduce vibration compared with traditional force control and impedance control.

scholarly journals Acoustic Characterization of Some Steel Industry Waste Materials

2021 ◽  
Vol 11 (13) ◽  
pp. 5924
Author(s):  
Elisa Levi ◽  
Simona Sgarbi ◽  
Edoardo Alessio Piana
Keyword(s):  
Thermal Characteristic ◽  
Environmental Benefits ◽  
Acoustic Properties ◽  
Physical Parameters ◽  
Industry Waste ◽  
Acoustic Characterization ◽  
Minimization Procedure ◽  
The Difference ◽  
By Products

From a circular economy perspective, the acoustic characterization of steelwork by-products is a topic worth investigating, especially because little or no literature can be found on this subject. The possibility to reuse and add value to a large amount of this kind of waste material can lead to significant economic and environmental benefits. Once properly analyzed and optimized, these by-products can become a valuable alternative to conventional materials for noise control applications. The main acoustic properties of these materials can be investigated by means of a four-microphone impedance tube. Through an inverse technique, it is then possible to derive some non-acoustic properties of interest, useful to physically characterize the structure of the materials. The inverse method adopted in this paper is founded on the Johnson–Champoux–Allard model and uses a standard minimization procedure based on the difference between the sound absorption coefficients obtained experimentally and predicted by the Johnson–Champoux–Allard model. The results obtained are consistent with other literature data for similar materials. The knowledge of the physical parameters retrieved applying this technique (porosity, airflow resistivity, tortuosity, viscous and thermal characteristic length) is fundamental for the acoustic optimization of the porous materials in the case of future applications.

scholarly journals Monopolar Diathermy Tonsillectomy Versus Dissection Method Tonsillectomy

KYAMC Journal ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 21-24
Author(s):  
Md Abdus Salam ◽  
Md Mahbub Alam ◽  
Rezwan Ahmed ◽  
Md Sultan Mahmud
Keyword(s):  
Postoperative Pain ◽  
Postoperative Bleeding ◽  
Throat Pain ◽  
Medical College ◽  
Advantages And Disadvantages ◽  
Case Surgery ◽  
Group A ◽  
The Difference ◽  
Group B ◽  
Dissection Method

Background: Tonsillectomy is one of the most common surgical procedures performed worldwide by otorhinolaryngologists for different indications. Tonsillectomy is often performed as day-case surgery, which increases the demands of a satisfactory postoperative pain control and a low risk of early postoperative bleeding. Objective: The aim of the study was to compare the Monopolar diathermy and Dissection methods of tonsillectomy and evaluate their advantages and disadvantages during surgery, convalescence. Materials and Methods: Two hundred children were recruited for this study during the period of five years from January, 2014 to December, 2018 at Otolaryngology department of Khwaja Yunus Ali Medical College and Hospital (KYAMCH). Subjects between the age of 5 and 25 years listed for tonsillectomy were included. Subjects were recommended not to have aspirin within the 2 weeks before surgery. Results: The mean duration of operation was found 10.6±0.4 minutes in group A and 17.0±0.7 minutes in group B. The difference was statistically significant (p<0.05) between two groups. At 1st day, 11(11.0%) patients had throat pain in group A and 23(23.0%) in group B. At 2nd day, 14(14.0%) patients had throat pain in group A and 25(25.0%) in group B. Which were statistically significant (p<0.05) between two groups. Conclusion: The monopolar diathermy tonsillectomy appears to cause less bleeding, postoperative pain and less time consuming in compare with the dissection tonsillectomy although patients experience slightly more pain than dissection Method. KYAMC Journal Vol. 10, No.-1, April 2019, Page 21-24

MicroRNA annotation in plants: current status and challenges

2021 ◽  
Author(s):  
Yongxin Zhao ◽  
Zheng Kuang ◽  
Ying Wang ◽  
Lei Li ◽  
Xiaozeng Yang
Keyword(s):  
Small Rna ◽  
Signal To Noise Ratio ◽  
Current Status ◽  
Mirna Biogenesis ◽  
Plant Mirnas ◽  
Signal To Noise ◽  
Advantages And Disadvantages ◽  
Plant Mirna ◽  
History Of ◽  
Mirna Biogenesis Pathway

Abstract Last two decades, the studies on microRNAs (miRNAs) and the numbers of annotated miRNAs in plants and animals have surged. Herein, we reviewed the current progress and challenges of miRNA annotation in plants. Via the comparison of plant and animal miRNAs, we pinpointed out the difficulties on plant miRNA annotation and proposed potential solutions. In terms of recalling the history of methods and criteria in plant miRNA annotation, we detailed how the major progresses made and evolved. By collecting and categorizing bioinformatics tools for plant miRNA annotation, we surveyed their advantages and disadvantages, especially for ones with the principle of mimicking the miRNA biogenesis pathway by parsing deeply sequenced small RNA (sRNA) libraries. In addition, we summarized all available databases hosting plant miRNAs, and posted the potential optimization solutions such as how to increase the signal-to-noise ratio (SNR) in these databases. Finally, we discussed the challenges and perspectives of plant miRNA annotations, and indicated the possibilities offered by an all-in-one tool and platform according to the integration of artificial intelligence.

Bias in estimates of mb at small magnitudes

1976 ◽  
Vol 66 (6) ◽  
pp. 1887-1904
Author(s):  
J. F. Evernden ◽  
W. M. Kohler
Keyword(s):  
Signal To Noise Ratio ◽  
High Signal ◽  
Systematic Bias ◽  
Station Correction ◽  
Signal To Noise ◽  
Identification Criterion ◽  
The Difference ◽  
Operational Networks ◽  
Worldwide Network ◽  
Simple Parameter

abstract A possibly significant factor in application of an identification criterion such as MS:mb is systematic bias in mb magnitude estimates at small magnitudes due to a variety of factors. Magnitude bias is the difference in magnitude value, positive or negative, between an observed network-based magnitude value and the expected magnitude value if all stations of the network had detected the event at high signal-to-noise ratio. This paper constitutes a partial study of the general problem; it evaluates the bias effects expected from both conceptual and operational networks when using parameters for noise and signal levels and standard deviations derived from observations, and when correcting observed station mb values solely via a simple parameter station correction factor. The analysis shows that any bias effects on mb inherent in any operational or potential worldwide network are so small as to have negligible effect on use of an MS:mb discriminant.

Parasitic aware impedance matching techniques for RF amplifiers

2011 ◽  
Vol 70 (1) ◽  
pp. 91-102 ◽  
Author(s):  
K. Dasgupta ◽  
A. Dutta ◽  
T. K. Bhattacharyya
Keyword(s):  
Impedance Matching ◽  
Rf Amplifiers ◽  
Matching Techniques
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