scholarly journals Development of Traveling Wave Actuators Using Waveguides of Different Geometrical Forms

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Ramutis Bansevicius ◽  
Dalius Mazeika ◽  
Vytautas Jurenas ◽  
Genadijus Kulvietis ◽  
Vytautas Bakanauskas
Keyword(s):  
Experimental Study ◽  
Numerical Modelling ◽  
Contact Surface ◽  
Experimental Analysis ◽  
Traveling Wave ◽  
Piezoelectric Actuators ◽  
Operating Principle ◽  
Contact Points ◽  
Cone Type ◽  
Different Types

The paper covers the research and development of piezoelectric traveling wave actuators using different types of the waveguides. The introduced piezoelectric actuators can be characterized by specific areas of application, different resolution, and torque. All presented actuators are ultrasonic resonant devices and they were developed to increase amplitudes of the traveling wave oscillations of the contact surface. Three different waveguides are introduced, that is, symmetrical, asymmetrical, and cone type waveguide. A piezoelectric ring with the sectioned electrodes is used to excite traveling wave oscillations for all actuators. Operating principle, electrode pattern, and excitation regimes of piezoelectric actuators are described. A numerical modelling of the actuators was performed to validate the operating principle and to calculate trajectories of the contact points motion. Prototype actuators were made and experimental study was performed. The results of numerical and experimental analysis are discussed.

scholarly journals Experimental analysis of the behaviour of different types of joints in the steel structure model subjected to earthquake loading

2021 ◽  
Vol 2070 (1) ◽  
pp. 012227
Author(s):  
T Jaroszewski ◽  
T Falborski ◽  
R Jankowski
Keyword(s):  
Experimental Study ◽  
Welded Joints ◽  
Experimental Analysis ◽  
Steel Structure ◽  
Shaking Table ◽  
Earthquake Loading ◽  
Structure Model ◽  
Seismic Excitations ◽  
Significant Difference ◽  
Different Types

Abstract The present paper reports the results of the experimental study performed to investigate the behaviour of two different types of joints (destroyed and welded ones) in the model of the steel structure under seismic excitations. The structure was subjected to three earthquakes, namely Kobe, Loma Prieta and Northridge, using the shaking table investigation. The results obtained from the study indicate that there is a significant difference between the behaviour of destroyed joints and welded ones. It was concluded that the destroyed joints experience higher acceleration than the welded joints during different earthquakes.

scholarly journals Assessment of Miniature Piezoelectric Travelling-Wave Beam and Plate Robots

2021 ◽  
Vol 8 (3) ◽  
pp. 199-216
Author(s):  
Adel Razek
Keyword(s):  
Traveling Wave ◽  
Autonomous Robots ◽  
Wave Beam ◽  
Piezoelectric Actuators ◽  
Travelling Wave ◽  
Thin Structures ◽  
Specific Medium ◽  
Piezoelectric Beam ◽  
Different Types ◽  
Amplifying Effect

Different up-to-date utilizations have found several benefits in condensing the size of autonomous robots. Miniature traveling wave piezoelectric robots have proven to be appropriate for many of these applications. The principles of locomotion embraced in these robots are mainly inspired by natural biological locomotion and could be categorized by their movement through a specific medium. In this article, after having highlighted the amplifying effect of piezoelectric actuators generating the locomotion necessary for robotic requests, we will review the different types of such locomotion. Next, we will discuss the traveling wave piezoelectric resonant robots. Succeeding, we will look at the operation and usages of piezoelectric beam and plate robots. Finally, we will discuss the modeling aspects implicated in these robots and more generally, the modeling of piezoelectric patches stuck on thin structures. Keywords: piezoelectric, miniature, travelling-wave, locomotion, beam and plate robots

The influence of information relevance on the continued influence effect of misinformation

2020 ◽  
Author(s):  
Hua Jin ◽  
Lina Jia ◽  
Xiaojuan Yin ◽  
Shilin Wei ◽  
Guiping Xu
Keyword(s):  
Experimental Study ◽  
Questionnaire Survey ◽  
Personal Involvement ◽  
Influence Effect ◽  
Information Relevance ◽  
Different Types ◽  
Role Of Information

Misinformation often continues to influence people’s cognition even after corrected (the ‘continued influence effect of misinformation’, the CIEM). This study investigated the role of information relevance in the CIEM by questionnaire survey and experimental study. The results showed that information with higher relevance to the individuals had a larger CIEM, indicating a role of information relevance in the CIEM. Personal involvement might explain the effects of information relevance on the CIEM. This study provides insightful clues for reducing the CIEM in different types of misinformation and misinformation with varying relevance.

scholarly journals About the Acceptance of Wearing Face Masks in Times of a Pandemic

i-Perception ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 204166952110211
Author(s):  
Claus-Christian Carbon
Keyword(s):  
Experimental Study ◽  
Social Group ◽  
Social Norm ◽  
Face Mask ◽  
Negative Consequences ◽  
Different Types ◽  
Study Participants

Wearing face masks in times of COVID-19 is one of the essential keystones for effectively decreasing the rate of new infections and thus for mitigating the negative consequences for individuals as well as for society. Acceptance of wearing masks is still low in many countries, making it extremely difficult to keep the pandemic at bay. In an experimental study, participants ( N = 88) had to assess how strange they felt when wearing a face mask while being exposed to displays of groups of varying numbers of mask wearers. Three different types of face masks were shown: simple homemade masks, FFP2 masks, and loop scarfs. The higher the frequency of people wearing masks in the displayed social group, the less strange the participants felt about themselves, an essential precondition for accepting wearing masks. This effect of a descriptive social norm was particularly effective when people saw others wearing less intrusive masks, here, simple homemade masks.

scholarly journals Computational and experimental analysis of timber beams with different types of flaws

2020 ◽  
Author(s):  
J. Kováčiková ◽  
O. Ivánková ◽  
S. Berg ◽  
M. Ekevad ◽  
T. Klas
Keyword(s):  
Experimental Analysis ◽  
Different Types ◽  
Timber Beams

Effects of ball properties on throwing in young team-handball beginners

2021 ◽  
pp. 174795412110236
Author(s):  
Frowin Fasold ◽  
Benjamin Noël ◽  
André Nicklas ◽  
Fabian Lukac ◽  
Stefanie Klatt
Keyword(s):  
Experimental Study ◽  
Movement Patterns ◽  
Team Handball ◽  
Throwing Accuracy ◽  
Different Types ◽  
Negative Effect ◽  
Study Participants

Throwing a ball is a primary skill in team-handball and can be directly influenced by the properties of different types of balls. Therefore, the use of different balls (i.e., methodic ball) recommended by the handball federations (e.g., IHF) and the education guidelines, are important in teaching throwing. Previous studies have shown that movement patterns and throwing velocity can be influenced by different ball types and sizes. However, the influence of these factors on throwing accuracy has not been investigated in detail yet. This study aims to replicate the findings of previous studies on increasing throwing velocity in children by comparing the use of a soft methodic ball with a size 0 handball. Furthermore, this study investigates the influence of these balls on throwing accuracy. In an experimental study, participants (10-years of age) threw a soft methodic ball and a size 0 ball at target areas in a handball goal. For all the throws, throwing velocity and accuracy were measured. Commensurate with previous research, throwing velocity was higher for the soft methodic ball compared to a size 0 ball. No difference was found in accuracy, although, it is worth mentioning that the participants were only experienced in throwing using the size 0 ball. Moreover, only one-third of the children favored throwing with a size 0 ball, which is what they are used to in training and competition. The results of our study, therefore, confirm that using soft methodic balls additionally, positively influences the throwing velocity and has no negative effect on the accuracy in throwing among young handball beginners.

scholarly journals Optimised calibration programmes for comparators for instrument transformers

2021 ◽  
Vol 88 (2) ◽  
pp. 122-131
Author(s):  
Christian Mester
Keyword(s):  
Experimental Study ◽  
Operating Principle ◽  
Device Under Test ◽  
Operating Range ◽  
Ratio Error ◽  
Phase Displacement ◽  
Instrument Transformers ◽  
Instrument Transformer ◽  
Method Of Measurement

Abstract Traditionally, instrument transformers are calibrated using bridges. By definition, bridges use the null method of measurement. The traditional calibration programme for instrument transformer bridges characterise namely this null measurement. Many new commercial comparators for instrument transformer use a very different method. They sample the secondary signals of reference and device under test (dut) transformer independently. Based on the samples, magnitude and phase of both signals are determined. Ratio error and phase displacement are calculated. Consequently, the significance of their calibration using the traditional calibration programme is limited. Moreover, the operating range of modern comparators is much larger than that of bridges. The additional versatility cannot be used without an adapted calibration programme. This article analyses the calibration programmes for both technologies. An experimental study confirms both the suitability of the new calibration programme and the need to chose the calibration programme depending on the technology of the device to be calibrated. The conclusion is very general and applies to all measurement problems where an operating principle is replaced by another – when changing the operating principle, it is important to check the calibration programme and adapt it if necessary.

Design of coaxial and waveguide couplers for helix TWT

Frequenz ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mukesh Kumar Alaria ◽  
Sanjay Kumar Ghosh
Keyword(s):  
Traveling Wave ◽  
Return Loss ◽  
Characteristic Impedance ◽  
Three Dimensional ◽  
Waveguide Coupler ◽  
Quarter Wavelength ◽  
Different Types ◽  
Waveguide Type ◽  
Transformer Design ◽  
Traveling Wave Tubes

Abstract In this paper, two types of coaxial coupler and waveguide coupler for different frequency helix traveling wave tubes (TWTs) are designed, fabricated and cold tested. The coaxial coupler includes of window ceramic and RF transformer section. At present multi-section impedance transformer design approach is used for wideband helix TWTs. In any helix TWT, impedance of the source is transformed to the characteristic impedance of helix. This is done by the quarter-wavelength (λ/4) impedance transformation approach. The simulated results of different types of couplers are carried out by HFSS and CST microwave studio software and compare with experimental results. Three-dimensional electromagnetic field simulators allowing the any geometry with port excitations it is possible to model the complex coaxial and waveguide type couplers with helix SWS assembly and predict its desired return loss performances.

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