Model Based Design of Piezoelectric Generators Utilizing Geometrical and Material Properties

Aerospace ◽  
2006 ◽  
Author(s):  
Bjo¨rn Richter ◽  
Jens Twiefel ◽  
Tobias Hemsel ◽  
Jo¨rg Wallaschek
Keyword(s):  
Output Power ◽  
Material Properties ◽  
General Model ◽  
Piezoelectric Element ◽  
Equivalent Model ◽  
Electric Load ◽  
Practical Applications ◽  
Model Based ◽  
Set Up

This paper presents a general model based on the electromechanical circuit theory. The model is set up as a mechanical equivalent model for base excited systems and describes the behaviour of a piezoelectric element around one resonance frequency which is sufficient for most practical applications. The model is extended to obtain the influence of geometrical and material properties. The derivated properties are used to describe the parameters of the general model which is easy to handle. Using this model either the calculation of the output power on a specific electric load or the determination of the design of the used piezoelectric element for a needed electric output power is possible. The paper focuses on the design of the ratio of length and width of a piezoelectric bimorph. The validity of the model is shown by the comparison of computed and experimental results.

scholarly journals Towards a Highly Sensitive Piezoelectric Nano-Mass Detection—A Model-Based Concept Study

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2533
Author(s):  
Jens Twiefel ◽  
Anatoly Glukhovkoy ◽  
Sascha de Wall ◽  
Marc Christopher Wurz ◽  
Merle Sehlmeyer ◽  
...  
Keyword(s):  
Piezoelectric Element ◽  
Element Model ◽  
Equivalent Model ◽  
Mass Detection ◽  
Bending Vibrations ◽  
Simultaneous Excitation ◽  
Model Based ◽  
Novel Approach ◽  
Highly Sensitive ◽  
First Time

The detection of exceedingly small masses still presents a large challenge, and even though very high sensitivities have been archived, the fabrication of those setups is still difficult. In this paper, a novel approach for a co-resonant mass detector is theoretically presented, where simple fabrication is addressed in this early concept phase. To simplify the setup, longitudinal and bending vibrations were combined for the first time. The direct integration of an aluminum nitride (AlN) piezoelectric element for simultaneous excitation and sensing further simplified the setup. The feasibility of this concept is shown by a model-based approach, and the underlying parameter dependencies are presented with an equivalent model. To include the geometrical and material aspects, a finite element model that supports the concept as a very promising approach for future nano-mass detectors is established.

scholarly journals Stochastic finite elements: Where is the physics?

2011 ◽  
Vol 38 (4) ◽  
pp. 379-396 ◽  
Author(s):  
Martin Ostoja-Starzewski
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Volume Element ◽  
Physical Content ◽  
Random Microstructure ◽  
Stochastic Finite Elements ◽  
Set Up ◽  
The Hill ◽  
The Given

The micromechanics based on the Hill-Mandel condition indicates that the majority of stochastic finite element methods hinge on random field (RF) models of material properties (such as Hooke?s law) having no physical content, or even at odds with physics. At the same time, that condition allows one to set up the RFs of stiffness and compliance tensors in function of the mesoscale and actual random microstructure of the given material. The mesoscale is defined through a Statistical Volume Element (SVE), i.e. a material domain below the Representative Volume Element (RVE) level. The paper outlines a procedure for stochastic scale-dependent homogenization leading to a determination of mesoscale one-point and two-point statistics and, thus, a construction of analytical RF models.

scholarly journals The Next Generation of International Law: Space, Ice, and the Cosmolegal Proposal

2021 ◽  
Vol 22 (2) ◽  
pp. 147-167
Author(s):  
Elena Cirkovic
Keyword(s):  
International Law ◽  
Outer Space ◽  
Ghg Emissions ◽  
Environmental Problems ◽  
The Arctic ◽  
Ontological Pluralism ◽  
Practical Applications ◽  
Broad Term ◽  
Set Up

AbstractWith the increasing environmental degradation in spaces most affected by climate change such as the Arctic, and the extension of anthropogenic environmental problems even into the Earth’s orbit, international law is confronted with some unprecedented challenges. Much of the legal dialogue surrounding this question is taking place in the abstract, such that there are no exact proposals for methodological and practical applications in lawmaking. In this Article, I argue that current governance relevant to the Arctic and outer space precedes an understanding of these spaces. Critical posthumanism, and other approaches, point out the continuation of strict boundaries that have been set up between the human body and the environment. International law’s formalist doctrinal deductions exacerbate these boundaries. I propose an approach to lawmaking under a broad term: the cosmolegal. The cosmolegal proposal challenges distinctions between human-made and non-human “laws”—scientific and social laws—and questions the foundational determination of both. The framework I suggest in this Article, therefore, requires a new approximation to accuracy in lawmaking, which could be achieved by greater interdisciplinarity and acceptance of ontological pluralism. This Article is divided into two broader sections. The first section focuses on two environmental problems: A) greenhouse gas (GHG) emissions in the Arctic and B) orbital debris. The second section argues for a different ontology of law and human self-understanding in the context of the unknown. It proposes “cosmolegality” in an attempt to approximate the inclusion and representation of ‘everything considered to be non-human.

Respirometry for determination of the influents SS-concentration

1996 ◽  
Vol 33 (1) ◽  
pp. 311-323 ◽  
Author(s):  
A. Witteborg ◽  
A. van der Last ◽  
R. Hamming ◽  
I. Hemmers
Keyword(s):  
Experimental Design ◽  
Activated Sludge ◽  
Substrate Concentration ◽  
Full Scale ◽  
Activated Sludge Process ◽  
Respiration Rates ◽  
On Line ◽  
Large Measurement ◽  
Set Up

A method is presented for determining influent readily biodegradable substrate concentration (SS). The method is based on three different respiration rates, which can be measured with a continuous respiration meter which is operated in a cyclic way. Within the respiration meter nitrification is inhibited through the addition of ATU. Simulations were used to develop the respirometry set-up and decide upon the experimental design. The method was tested as part of a large measurement programme executed at a full-scale plant. The proposed respirometry set-up has been shown to be suitable for a semi-on-line determination of an influent SS which is fully based on the IAWQ #1 vision of the activated sludge process. The YH and the KS play a major role in the principle, and should be measured directly from the process.

Determining the Norton’s Equivalent Model of Distribution System with Distributed Generation (DG) for Stability Analysis

2019 ◽  
Vol 12 (2) ◽  
pp. 190-198
Author(s):  
Sunny Katyara ◽  
Lukasz Staszewski ◽  
Faheem Akhtar Chachar
Keyword(s):  
Distributed Generation ◽  
Normal Condition ◽  
Distribution System ◽  
Distribution Networks ◽  
Equivalent Model ◽  
Stability Factor ◽  
Matlab Simulation ◽  
The Stability ◽  
Stability Issues

Background: Since the distribution networks are passive until Distributed Generation (DG) is not being installed into them, the stability issues occur in the distribution system after the integration of DG. Methods: In order to assure the simplicity during the calculations, many approximations have been proposed for finding the system’s parameters i.e. Voltage, active and reactive powers and load angle, more efficiently and accurately. This research presents an algorithm for finding the Norton’s equivalent model of distribution system with DG, considering from receiving end. Norton’s model of distribution system can be determined either from its complete configuration or through an algorithm using system’s voltage and current profiles. The algorithm involves the determination of derivative of apparent power against the current (dS/dIL) of the system. Results: This work also verifies the accuracy of proposed algorithm according to the relative variations in the phase angle of system’s impedance. This research also considers the varying states of distribution system due to switching in and out of DG and therefore Norton’s model needs to be updated accordingly. Conclusion: The efficacy of the proposed algorithm is verified through MATLAB simulation results under two scenarios, (i) normal condition and (ii) faulty condition. During normal condition, the stability factor near to 1 and change in dS/dIL was near to 0 while during fault condition, the stability factor was higher than 1 and the value of dS/dIL was away from 0.

Determination of trace concentrations of copper by FIA-FAAS after preconcentration on chelating sorbents

1989 ◽  
Vol 54 (7) ◽  
pp. 1785-1794 ◽  
Author(s):  
Vlastimil Kubáň ◽  
Josef Komárek ◽  
Zbyněk Zdráhal
Keyword(s):  
Sampling Frequency ◽  
Copper Determination ◽  
Flow Rates ◽  
Sample Injection ◽  
Injection Flow ◽  
Chelating Sorbents ◽  
Set Up ◽  
Trace Concentrations ◽  
Better Than

A FIA-FAAS apparatus containing a six-channel sorption equipment with five 3 x 26 mm microcolumns packed with Spheron Oxin 1 000, Ostsorb Oxin and Ostsorb DTTA was set up. Combined with sorption from 0.002M acetate buffer at pH 4.2 and desorption with 2M-HCl, copper can be determined at concentrations up to 100, 150 and 200 μg l-1, respectively. For sample and eluent flow rates of 5.0 and 4.0 ml min-1, respectively, and a sample injection time of 5 min, the limit of copper determination is LQ = 0.3 μg l-1, repeatability sr is better than 2% and recovery is R = 100 ± 2%. The enrichment factor is on the order of 102 and is a linear function of time (volume) of sample injection up to 5 min and of the sample injection flow rate up to 11 ml min-1 for Spheron Oxin 1 000 and Ostsorb DTTA. For times of sorption of 60 and 300 s, the sampling frequency is 70 and 35 samples/h, respectively. The parameters of the FIA-FAAS determination (acetylene-air flame) are comparable to or better than those achieved by ETA AAS. The method was applied to the determination of traces of copper in high-purity water.

Extra-Column Effects in Determination of Rate Parameters by the Chromatographic Method

1996 ◽  
Vol 61 (6) ◽  
pp. 844-855 ◽  
Author(s):  
Olga Šolcová ◽  
Petr Schneider
Keyword(s):  
Chromatographic Method ◽  
Dynamic Method ◽  
Axial Dispersion ◽  
Transport Parameters ◽  
Porous Particles ◽  
Loop Detector ◽  
Single Pellet ◽  
Set Up ◽  
Extra Column Effects

It was shown that the sampling loop, detector and connecting elements in the chromatographic set-up for determination of transport parameters by the dynamic method significantly influence the response peaks from columns packed with porous or nonporous particles. A method, based on the use of convolution theorem, was developed which can take these effects into account. The applicability of this method was demonstrated on the case of axial dispersion in a single-pellet-string column (SPSR) packed with nonporous particles. It is possible to handle also responses from columns packed with porous particles by a similar procedure.

Determination of Charge Coefficient of Piezoelectric Films Using a Combined Finite Element Model and Dynamic Loading Technique

2020 ◽  
Vol 835 ◽  
pp. 229-242
Author(s):  
Oboso P. Bernard ◽  
Nagih M. Shaalan ◽  
Mohab Hossam ◽  
Mohsen A. Hassan
Keyword(s):  
Finite Element ◽  
Dynamic Loading ◽  
Material Properties ◽  
Accurate Determination ◽  
Substrate Material ◽  
Experimental Results ◽  
Piezoelectric Composite ◽  
Piezoelectric Film ◽  
Piezoelectric Charge

Accurate determination of piezoelectric properties such as piezoelectric charge coefficients (d33) is an essential step in the design process of sensors and actuators using piezoelectric effect. In this study, a cost-effective and accurate method based on dynamic loading technique was proposed to determine the piezoelectric charge coefficient d33. Finite element analysis (FEA) model was developed in order to estimate d33 and validate the obtained values with experimental results. The experiment was conducted on a piezoelectric disc with a known d33 value. The effect of measuring boundary conditions, substrate material properties and specimen geometry on measured d33 value were conducted. The experimental results reveal that the determined d33 coefficient by this technique is accurate as it falls within the manufactures tolerance specifications of PZT-5A piezoelectric film d33. Further, obtained simulation results on fibre reinforced and particle reinforced piezoelectric composite were found to be similar to those that have been obtained using more advanced techniques. FE-results showed that the measured d33 coefficients depend on measuring boundary condition, piezoelectric film thickness, and substrate material properties. This method was proved to be suitable for determination of d33 coefficient effectively for piezoelectric samples of any arbitrary geometry without compromising on the accuracy of measured d33.

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