scholarly journals Operation of vibration source of an unbalance type with liquid-filled internal working chamber

2021 ◽  
Vol 2131 (2) ◽  
pp. 022066
Author(s):  
A Savchenko ◽  
A Nikolaev ◽  
D Evstigneev
Keyword(s):  
Electric Drive ◽  
Low Frequency ◽  
Rotation Frequency ◽  
Vertical Position ◽  
Vibration Source ◽  
Thermal Imager ◽  
Working Chamber ◽  
Internal Working ◽  
Seismic Vibrations ◽  
Source Operation

Abstract Equipment for increasing water inflow to the well is proposed, which affects the aquifer by seismic vibrations. The method is based on accelerating the filtration process in soils, exposed to vibration. The equipment can work in conjunction with a submersible pump and has the ability to pump liquid through the working chamber of the generator. Generators can be combined into a group and driven by one electric motor to increase the efficiency of vibration treatment. This method is built into the existing technology of dewatering and pits drainage. The dynamics of the vibration source operation of an unbalance type with a liquid-filled inner chamber was studied in laboratory conditions, on a test. The vibration source was attached to the stand frame and was in a vertical position coaxially with the electric drive, thereby simulating its location in the well. The unbalance was unwound by an electric drive with a rotation frequency of 10 to 50 Hz in 5 Hz steps and seismic vibrations, generated by a vibration source, were recorded. Based on the experiments’ results, the amplitude-frequency characteristics of an unbalanced vibration source in the low-frequency range with a dry and liquid-filled inner chamber were obtained. In order to prevent the bearing assemblies from jamming, their heating was monitored with a thermal imager and temperature sensors.

scholarly journals The Tangential Force Affecting the Radial Baffles in a Stirred Vessel: Analysis of the Macro-instability Related Component

10.14311/450 ◽  
2003 ◽  
Vol 43 (4) ◽  
Author(s):  
P. Hasal ◽  
I. Fořt ◽  
J. Kratěna
Keyword(s):  
Experimental Data ◽  
Spectral Analysis ◽  
Tangential Force ◽  
Low Frequency ◽  
Frequency Component ◽  
Relative Magnitude ◽  
Tangential Component ◽  
Vertical Position ◽  
Total Force ◽  
Rushton Turbine

Experimental data obtained by measuring the tangential component of the force affecting radial baffles in a flat-bottomed cylindrical mixing vessel stirred with a Rushton turbine impeller is analysed. Spectral analysis of the experimental data demonstrated the presence of its macro-instability (MI) related low-frequency component embedded in the total force. Two distinct dimensionless frequencies (both directly proportional to the impeller speed of rotation N) of the occurence of the MI component were detected: a lower frequency of approximately 0.025N and a higher frequency of about 0.085N. The relative magnitude QMI of the MI-related component of the total tangential force was evaluated by a combination of proper orthogonal decomposition (POD) and spectral analysis. The values of magnitude QMI varied in the interval [rom approximately 0.05 to 0.30. The magnitude QMI takes maximum values at low Reynolds number values (in laminar and transitional regions). In the turbulent region (ReM >20000) the QMI value is low and practically constant. The dependence oj the QMI values on vertical position in the vessel is only marginal. The results suggest that the magnitude of the MI component of the force is significantly influenced by the liquid viscosity and density.

scholarly journals Piezoelectric Energy Harvesting with an Ultrasonic Vibration Source

Actuators ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 8
Author(s):  
Tao Li ◽  
Pooi Lee
Keyword(s):  
Energy Harvesting ◽  
High Power ◽  
High Frequency ◽  
Energy Harvester ◽  
Impedance Matching ◽  
Low Frequency ◽  
Vibration Source ◽  
Piezoelectric Energy ◽  
Power Ultrasonic ◽  
Ultrasonic Cutting

A piezoelectric energy harvester was developed in this paper. It is actuated by the vibration leakage from the nodal position of a high-power ultrasonic cutting transducer. The harvester was excited at a low displacement amplitude (0.73 µmpp). However, its operation frequency is quite high and reaches the ultrasonic range (24.4 kHz). Compared with another low frequency harvester (66 Hz), both theoretical and experimental results proved that the advantages of this high frequency harvester include (i) high current generation capability (up to 20 mApp compared to 1.3 mApp of the 66 Hz transducer) and (ii) low impedance matching resistance (500 Ω in contrast to 50 kΩ of the 66 Hz transducer). This energy harvester can be applied either in sensing, or vibration controlling, or simply energy harvesting in a high-power ultrasonic system.

scholarly journals Electromechanical coupling dynamic modeling and analysis of vertical electrodynamic shaker considering low frequency lateral vibration

2020 ◽  
Vol 12 (10) ◽  
pp. 168781402096385
Author(s):  
Shuguang Zuo ◽  
Zhaoyang Feng ◽  
Jian Pan ◽  
Xudong Wu
Keyword(s):  
Dynamic Model ◽  
Electromechanical Coupling ◽  
Low Frequency ◽  
Coupling Model ◽  
Vertical Position ◽  
Force Model ◽  
Lateral Vibration ◽  
Modeling And Analysis ◽  
Electrodynamic Shaker ◽  
Coupling Dynamic

For the problem of relatively severe lateral vibration found in the vertical electrodynamic shaker experiment, an electromechanical coupling dynamic model of the electrodynamic shaker considering low-frequency lateral vibration is proposed. The reason and mechanism of the lateral vibration is explained and analyzed through this model. To establish this model, an electromagnetic force model of overall conditions is firstly built by fitting force samples with neural network method. The force samples are obtained by orthogonal test of finite element simulation, in which five factors of the moving coil including current, vertical position, flipping eccentricity angle, radial translational eccentric direction and distance are considered. Secondly, a 7-dof dynamic model of the electrodynamic shaker is developed with the consideration of the lateral vibration of the moving system. To obtain the transfer function accurately, the stiffness and damping parameters are identified. Finally, an electromechanical dynamic model is established by coupling the force model and the 7-dof dynamic model, and it is verified by experiments. The coupling model proposed can be further used for the control and optimization of the electrodynamic shaker.

scholarly journals The Effects of Rapid Rotation on Pulsation

2002 ◽  
Vol 185 ◽  
pp. 177-185
Author(s):  
Hideyuki Saio
Keyword(s):  
Low Frequency ◽  
Rotation Frequency ◽  
Rotating Stars ◽  
Frequency Shifts ◽  
Rapid Rotation ◽  
The Stability

AbstractWe discuss the properties of pulsations in rotating stars, which include frequency shifts, the effects on the stability of p- and g-modes, and the properties of low-frequency modes whose frequencies are comparable to or less than the rotation frequency.

scholarly journals Grunting for worms: seismic vibrations cause Diplocardia earthworms to emerge from the soil

2008 ◽  
Vol 5 (1) ◽  
pp. 16-19 ◽  
Author(s):  
O Mitra ◽  
M.A Callaham ◽  
M.L Smith ◽  
J.E Yack
Keyword(s):  
Low Frequency ◽  
Seismic Signal ◽  
Metal Object ◽  
Common Assumption ◽  
Southeastern Usa ◽  
Object A ◽  
Seismic Vibrations

Harvesting earthworms by a practice called ‘worm grunting’ is a widespread and profitable business in the southeastern USA. Although a variety of techniques are used, most involve rhythmically scraping a wooden stake driven into the ground, with a flat metal object. A common assumption is that vibrations cause the worms to surface, but this phenomenon has not been studied experimentally. We demonstrate that Diplocardia earthworms emerge from the soil within minutes following the onset of grunting. Broadband low frequency (below 500 Hz) pulsed vibrations were present in the soil throughout the area where worms were harvested, and the number of worms emerging decreased as the seismic signal decayed over distance. The findings are discussed in relation to two hypotheses: that worms are escaping vibrations caused by digging foragers and that worms are surfacing in response to vibrations caused by falling rain.

Development of Fixing System for 2-Axis Micro Deep Drilling Assisted by Low Frequency Vibration

2014 ◽  
Vol 625 ◽  
pp. 149-154 ◽  
Author(s):  
Ivan Burdukovskyi ◽  
Jun'ichi Kaneko ◽  
Kenichiro Horio
Keyword(s):  
Amplitude Ratio ◽  
Low Frequency ◽  
Two Dimensions ◽  
Drilling Process ◽  
Vibration Source ◽  
Deep Drilling ◽  
Machining Time ◽  
Hard Materials ◽  
Low Frequency Vibration ◽  
Vertical Displacements

Micro deep drilling of hard materials is required to involve step feed in process that grows up machining time. To increase the step feed, a method with low frequency vibration (frequency ~190 Hz, amplitude ~10 μm) by oscillating of workpiece has been proposed. Previous study is focused on method of 1-axis drilling process assisted by low frequency vibration. Introducing the method with low frequency vibration to 2-axis drilling process on a curved surface is required to oscillate the workpiece in two dimensions. Purpose of our study is to design fixing system with the 2-dimansional low frequency vibration. Vibration source is needed to change for providing the 2-dimansional vibration. Fixing system for 2-dimensional vibration (FS2DV) consists of two vibration sources in horizontal and vertical directions with spring systems along it action. The 2-dimensional vibration is controlled by amplitude ratio of the vibrations from each source. As a result, we have succeeded low frequency vibration of the workpiece with assigned direction. The resulting vibration is verified (measuring of instantaneous horizontal and vertical displacements).

Simulation on Flow Field Induced by Vibration Surface of Low Frequency

2010 ◽  
Author(s):  
Ling Shen ◽  
Shuhong Liu ◽  
Yulin Wu
Keyword(s):  
Flow Field ◽  
Velocity Distribution ◽  
Numerical Computation ◽  
High Frequency ◽  
Ultrasonic Transducer ◽  
Sewage Treatment ◽  
Low Frequency ◽  
Vibration Source ◽  
Water Tank ◽  
Industrial Cleaning

Ultrasonic cavitation generated by high-frequency ultrasonic transducer is widely studied because this phenomenon could be applied in a great variety of fields, including medical therapy, industrial cleaning as well as sewage treatment. Flow field influenced by vibration source of low frequency, however, is less studied. For the present study, a water tank of 1000×600×500mm is investigated when a vibration surface that represents a transducer of less frequency vibrates in the vicinity of one wall. Numerical computation based on the method of dynamic mesh is applied. Furthermore, two different vibration patterns are simulated, i.e., piston movement and drumhead vibration. Results show different pressure and velocity distribution within water tank when vibration surface is working at various frequencies and amplitudes. Differences of the flow fields are found between these circumstances, and similarity is found with that induced by ultrasonic transducer. Analysis on differences is discussed for further study.

scholarly journals Performance Enhancement of a Multiresonant Piezoelectric Energy Harvester for Low Frequency Vibrations

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2770 ◽  
Author(s):  
Iman Izadgoshasb ◽  
Yee Lim ◽  
Ricardo Vasquez Padilla ◽  
Mohammadreza Sedighi ◽  
Jeremy Novak
Keyword(s):  
Cantilever Beam ◽  
Performance Enhancement ◽  
Low Frequency ◽  
Design Parameters ◽  
Vibration Source ◽  
Element Analysis ◽  
Energy Harvesters ◽  
Piezoelectric Energy ◽  
Low Frequency Vibration ◽  
External Power Source

Harvesting electricity from low frequency vibration sources such as human motions using piezoelectric energy harvesters (PEH) is attracting the attention of many researchers in recent years. The energy harvested can potentially power portable electronic devices as well as some medical devices without the need of an external power source. For this purpose, the piezoelectric patch is often mechanically attached to a cantilever beam, such that the resonance frequency is predominantly governed by the cantilever beam. To increase the power generated from vibration sources with varying frequency, a multiresonant PEH (MRPEH) is often used. In this study, an attempt is made to enhance the performance of MRPEH with the use of a cantilever beam of optimised shape, i.e., a cantilever beam with two triangular branches. The performance is further enhanced through optimising the design of the proposed MRPEH to suit the frequency range of the targeted vibration source. A series of parametric studies were first carried out using finite-element analysis to provide in-depth understanding of the effect of each design parameters on the power output at a low frequency vibration. Selected outcomes were then experimentally verified. An optimised design was finally proposed. The results demonstrate that, with the use of a properly designed MRPEH, broadband energy harvesting is achievable and the efficiency of the PEH system can be significantly increased.

Monitoring Seismicity on Mars - the Marsquake Service for InSight

2020 ◽  
Author(s):  
John Clinton ◽  
Domenico Giardini ◽  
Savas Ceylan ◽  
Martin van Driel ◽  
Simon Stähler ◽  
...  
Keyword(s):  
High Frequency ◽  
Body Wave ◽  
A Priori ◽  
Broad Band ◽  
Low Frequency ◽  
Ambient Vibration ◽  
Crustal Layer ◽  
Seismic Waveforms ◽  
Seismic Vibrations ◽  
Back Azimuth

<p>InSight landed on Mars in late November 2018, and the SEIS seismometer package was fully deployed by February 2019. By January 2020, SEIS continues to exceed performance expectations in terms of observed minimum noise. The Marsquake Service (MQS) has been setup to create and curate a seismicity catalogue for Mars over the lifetime of the InSight mission. Seismic waveforms are downloaded daily from the station and are analysed and processed by the MarsQuake Service, with the goal of detecting seismic vibrations not due to local ambient sources. To this end, every precaution is applied to eliminate possible non-seismic sources, such as noise induced by atmospheric phenomena, lander vibrations and orbiter activity. At the date of submission, we have detected 365 events, of different quality and SNR levels. Signal amplitudes remain small and signal can generally only be detected at night. Some events show only low-frequency waves in the 1-10 sec band, others have a high-frequency content up to several Hz, and others have a more broad-band character. A special class of events involves the excitation of a very prominent ambient vibration at 2.4Hz. Despite the scattered nature of the energy, in many cases, distinct phases can be inferred in the waveforms. Body wave character, and back-azimuth, can only be confirmed for 3 broadband events so far.  The MQS approach for determining distances from broadband events identifies phases as mantle P and S-phases and uses an a priori set of several thousand martian models, derived from geophysical, mineralogical and orbital constraints. High frequency events are currently located assuming phases are trapped crustal Pg and Sg and using a simple crustal layer. The MQS works in conjunction with the Mars Structural Service (MSS) on building and adopting updated models. The MQS consists of an international team of seismologists that screen incoming data to identify and characterise any seismicity. In this presentation, we present the MQS, demonstrate how we detect and characterise marsquakes, and describe the challenges we face dealing with the Martian dataset.</p>

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