scholarly journals A complete thermo-electro-viscoelastic characterization of dielectric elastomers, Part I: Experimental investigations

2021 ◽  
pp. 104603
Author(s):  
Markus Mehnert ◽  
Mokarram Hossain ◽  
Paul Steinmann
Keyword(s):  
Dielectric Elastomers ◽  
Experimental Investigations

Investigations into the Precessing Vortex Core Phenomenon in Cyclone Dust Separators

1994 ◽  
Vol 208 (2) ◽  
pp. 147-154 ◽  
Author(s):  
P Yazdabadi ◽  
A J Griffiths ◽  
N Syred
Keyword(s):  
Vortex Core ◽  
Reynolds Numbers ◽  
Frequency Parameter ◽  
Experimental Investigations ◽  
Swirl Number ◽  
Significant Drop ◽  
Precessing Vortex Core ◽  
Dust Separator ◽  
The Relationship

Experimental investigations have been carried out to examine the effect of downstream pipework configurations on the precessing vortex core (PVC) generated within the exhaust region of a cyclone dust separator. Characterization of the PVC using a non-dimensionalized frequency parameter (NDFP) was used to determine the relationship between Reynolds number and geometrical swirl number of the cyclone. The results show that the NDFP tends towards an asymptotic value for Reynolds numbers of about 50 000 and high swirl numbers (> 3.043). This value is reached earlier with lower swirl numbers. It was concluded that any exhaust pipework configuration produced a significant drop in the PVC frequency, and certain configurations either delayed or promoted the development of the PVC.

scholarly journals Simulations and Experimental Investigations on the Acoustic Characterization of Centrifugal Pumps of Different Specific Speed

2019 ◽  
Vol 4 (3) ◽  
pp. 16
Author(s):  
Christian Lehr ◽  
Andreas Linkamp ◽  
Daniel Aurich ◽  
Andreas Brümmer
Keyword(s):  
Dynamic Pressure ◽  
Pressure Sensors ◽  
Dipole Source ◽  
Experimental Investigations ◽  
Acoustic Excitation ◽  
Centrifugal Pumps ◽  
Transmission Parameters ◽  
Acoustic Characterization ◽  
Specific Speed

Subject of discussion are simulations and experimental investigations on the acoustic characterization of three single stage centrifugal pumps of different specific speed. In operation, these pump-types generate pressure pulsation at blade passing frequency, primarily due to rotor-volute-interaction. In order to determine the acoustic excitation it is necessary to know about the pumps’ acoustic transmission parameters. In this paper, a one-dimensional numerical model for transient time-domain simulation is presented, which takes into account the pump geometry as well as the volutes’ structural behaviour by means of the local effective speed of sound. Numerical results for the transmission characteristics of the three different pumps are shown in terms of scattering matrices and evaluated against parameters calculated from measurement results. The experimental analyses are carried out using dynamic pressure sensors in both the suction and the discharge pipe. Assuming solely plane wave propagation, the complex acoustic field on each side is evaluated independently. The so called “two source” method is then used to determine the transmission parameters of the pumps in standstill for a range of frequencies experimentally. Subsequently, the acoustic excitation at varying rotational speed is evaluated by means of measurements at the pumps in operation and presented as monopole and dipole source types for cavitation-free conditions.

Corrosion of T91 Steel in LBE: Contribution to the Study of the Pb–Bi–O–Fe–Hg System - Thermodynamic Description of PbO–Fe2O3

2008 ◽  
Vol 595-598 ◽  
pp. 473-481 ◽  
Author(s):  
Ibra Diop ◽  
N. David ◽  
J.M. Fiorani ◽  
Renaud Podor ◽  
Michel Vilasi
Keyword(s):  
Thermodynamic Assessment ◽  
Isothermal Annealing ◽  
Nuclear Reactors ◽  
Thermodynamic Description ◽  
Calphad Method ◽  
Experimental Investigations ◽  
Degradation Mechanisms ◽  
Spallation Target ◽  
Thermocalc Software

The knowledge of the quinary Pb–Bi–O–Fe–Hg is necessary for understanding the degradation mechanisms of the T91 steel used as structural material in future ADS nuclear reactors. In this device, the steel will be in direct contact with the liquid spallation target (which is constituted by lead or lead-bismuth eutectic) surrounded by a reduced oxygen pressure atmosphere. In the present work, the characterization of the pseudo-binary PbO–Fe2O3 cut has been performed. In order to complete the available data in the literature, some experimental investigations by DTA, isothermal annealing, SEM and EPMA have been done. These results have allowed proposing a thermodynamic assessment using the Calphad method by the ThermoCalc software.

scholarly journals Mechanical characterization and numerical modeling of laser-sintered TPE lattice structures

2021 ◽  
Author(s):  
Christina Kummert ◽  
Hans-Joachim Schmid ◽  
Lena Risse ◽  
Gunter Kullmer
Keyword(s):  
Numerical Modeling ◽  
Thermoplastic Elastomer ◽  
Experimental Investigations ◽  
Lattice Structures ◽  
Sintering Process ◽  
Compression Tests ◽  
Plastic Properties ◽  
Cell Parameters ◽  
Cyclic Compression

Abstract Additive Manufacturing provides the opportunity to produce tailored and complex structures economically. The use of lattice structures in combination with a thermoplastic elastomer enables the generation of structures with configurable properties by varying the cell parameters. Since there is only little knowledge about the producibility of lattice structures made of TPE in the laser sintering process and the resulting mechanical properties, different kinds of lattice structures are investigated within this work. The cell type, cell size and strut thickness of these structures are varied and analyzed. Within the experimental characterization of Dodecahedron-cell static and cyclic compression tests of sandwich structures are focused. The material exhibits hyperelastic and plastic properties and also the Mullins-Effect. For the later design of real TPE structures, the use of numerical methods helps to reduce time and costs. The preceding experimental investigations are used to develop a concept for the numerical modeling of TPE lattice structures. Graphic abstract

Development, manufacturing, and validation of a dielectric elastomer membrane actuator–driven contactor

2018 ◽  
Vol 30 (4) ◽  
pp. 636-648 ◽  
Author(s):  
Philipp Linnebach ◽  
Filomena Simone ◽  
Gianluca Rizzello ◽  
Stefan Seelecke
Keyword(s):  
New Technology ◽  
Dynamic Performance ◽  
Dielectric Elastomer ◽  
Dielectric Elastomers ◽  
Mechatronic Systems ◽  
Additional Advantage ◽  
Out Of Plane ◽  
Actuator System ◽  
Dielectric Elastomer Membrane

Dielectric elastomers represent a relatively new technology with high potentials for actuators’ applications. Thanks to their lightweight, fast operations, energy efficiency, low power consumption, large deformations, and high scalability, dielectric elastomers permit to develop novel mechatronic systems capable of overperforming standard actuation technologies, such as solenoid valves, in several applications. This article presents a novel design for a dielectric elastomer–driven actuator system which enables closing and opening of a contactor. The design is based on a combination between circular out-of-plane dielectric elastomer membranes and a bi-stable biasing system which allows to increase the out-of-plane stroke. Characterization of the contactor is initially performed in order to establish the actuator requirements in terms of force and stroke. Then, systematic design and manufacturing are carried out for both dielectric elastomer membranes and biasing mechanism. Finally, the effectiveness of the actuator in closing and opening the contactor is validated experimentally. The results show comparable dynamic performance to a conventional electromagnetic drive, with the additional advantage of a significantly lower energy consumption.

Arc Discharge Synthesis of Oxides and Carbides of Tungsten and Aluminum

2013 ◽  
Vol 8 (2) ◽  
pp. 95-101
Author(s):  
Alexey Zaikovsky ◽  
Aleksandr Fedoseev ◽  
Salavat Sakhapov ◽  
Anton Evtushenko ◽  
Marina Serebriakova ◽  
...  
Keyword(s):  
Arc Discharge ◽  
Experimental Investigations ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
X Ray Diffraction ◽  
X Ray ◽  
Synthesis Of Nanoparticles ◽  
Synthesized Materials ◽  
Discharge Method

Experimental investigations of the possibility of arc discharge method for synthesis of nanoparticles of oxides and carbides of tungsten and aluminum have been presented. The method is based on anode atomization of composed graphite – aluminum and graphite – WO3 electrodes. The transmitted electron microscopy, thermal gravimetric analysis and X-ray diffraction were applied for the characterization of morphology and properties of synthesized materials. It was experimentally shown the arc discharge method allows to syntheses the nanoparticles of oxides and carbides of tungsten and aluminum

Polarizing Optical Microscopic Characterization of Nematic Liquid Crystal Confined in Porous Silicon

2011 ◽  
Vol 181-182 ◽  
pp. 83-87
Author(s):  
Yuan Ming Huang ◽  
Qing Lan Ma ◽  
Bao Gai Zhai
Keyword(s):  
Experimental Study ◽  
Liquid Crystal ◽  
Porous Silicon ◽  
Optical Microscopy ◽  
Nematic Liquid Crystal ◽  
Experimental Investigations ◽  
Electro Optic ◽  
The Given

With polarizing optical microscopy we have investigated the electro-optic properties of a nematic liquid crystal 4-n-pentyl-4′-cyanobipheny confined in the microchannels of porous silicon. Experimental study shows clearly that the liquid crystal molecules tend to align parallel to the direction of the pore columns in porous silicon. Schlieren textures with S = +1 and +2 disclinations were recorded. Our experimental investigations show that uniaxial alignment, the planar radial and the escaped radial configurations exist around the given microchannels of porous silicon.

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