@inproceedings{9783, abstract = {{To optimize the ultrasound irradiation for cavitation based ultrasound applications like sonochemistry or ultrasound cleaning, the correlation between cavitation intensity and the resulting effect on the process is of interest. Furthermore, changing conditions like temperature and pressure result in varying acoustic properties of the liquid. That might necessitate an adaption of the ultrasound irradiation. To detect such changes during operation, process monitoring is desired. Labor intensive processes, that might be carried out for several hours, also require process monitoring to increase their reliability by detection of changes or malfunctions during operation. In some applications cavitation detection and monitoring can be achieved by the application of sensors in the sound field. Though the application of sensors is possible, this necessitates modifications on the system and the sensor might disturb the sound field. In other applications harsh, process conditions prohibit the application of sensors in the sound field. Therefore alternative techniques for cavitation detection and monitoring are desired. The applicability of an external microphone and a self-sensing ultrasound transducer for cavitation detection were experimentally investigated. Both methods were found to be suitable and easily applicable.}}, author = {{Bornmann, Peter and Hemsel, Tobias and Sextro, Walter and Maeda, Takafumi and Morita, Takeshi}}, booktitle = {{Ultrasonics Symposium (IUS), 2012 IEEE International}}, issn = {{1948-5719}}, keywords = {{cavitation, chemical reactors, microphones, process monitoring, reliability, ultrasonic applications, ultrasonic waves, acoustic properties, cavitation based ultrasound applications, cavitation intensity, change detection reliability, external microphone, malfunction detection reliability, nonperturbing cavitation detection, nonperturbing cavitation monitoring, process monitoring, self-sensing ultrasound transducer, sonochemical reactors, sonochemistry, ultrasound cleaning, ultrasound irradiation, Acoustics, Liquids, Monitoring, Sensors, Sonar equipment, Transducers, Ultrasonic imaging}}, pages = {{1141--1144}}, title = {{{Non-perturbing cavitation detection / monitoring in sonochemical reactors}}}, doi = {{10.1109/ULTSYM.2012.0284}}, year = {{2012}}, } @inproceedings{9784, abstract = {{Piezoelectric inertia motors use the inertia of a body to drive it by means of a friction contact in a series of small steps. These motors can operate in ``stick-slip'' or ``slip-slip'' mode, with the fundamental frequency of the driving signal ranging from several Hertz to more than 100 kHz. To predict the motor characteristics, a Coulomb friction model is sufficient in many cases, but numerical simulation requires microscopic time steps. This contribution proposes a much faster simulation technique using one evaluation per period of the excitation signal. The proposed technique produces results very close to those of timestep simulation for ultrasonics inertia motors and allows direct determination of the steady-state velocity of an inertia motor from the motion profile of the driving part. Thus it is a useful simulation technique which can be applied in both analysis and design of inertia motors, especially for parameter studies and optimisation.}}, author = {{Hunstig, Matthias and Hemsel, Tobias and Sextro, Walter}}, booktitle = {{Ultrasonics Symposium (IUS), 2012 IEEE International}}, issn = {{1948-5719}}, keywords = {{friction, ultrasonic motors, Coulomb friction model, efficient simulation technique, friction contact, high-frequency piezoelectric inertia motor, motor characteristics prediction, numerical simulation, slip-slip mode, stick-slip mode, time-step simulation, ultrasonic inertia motor, Acceleration, Acoustics, Actuators, Computational modeling, Friction, Numerical models, Steady-state}}, pages = {{277--280}}, title = {{{An efficient simulation technique for high-frequency piezoelectric inertia motors}}}, doi = {{10.1109/ULTSYM.2012.0068}}, year = {{2012}}, } @inproceedings{9788, abstract = {{A hydrothermal method utilizes a crystallization process in the solution so that the pure and high-quality powders can be realized. Sintering from the hydrothermal KNbO3 and NaNbO3 powders, a high-dense lead-free piezoelectric (K,Na)NbO3 ceramics could be obtained (density: 98.8\%). Concerning about the g33 constant, high value as large as commercial PZT ceramics was measured. Therefore, the hydrothermal (K,Na)NbO3 ceramics is usable for the sensors and the energy harvesting devices. To demonstrate the (K,Na)NbO3 ceramics, a hydrophone sensor was fabricated and evaluated.}}, author = {{Maeda, Takafumi and Bornmann, Peter and Hemsel, Tobias and Morita, Takeshi}}, booktitle = {{Ultrasonics Symposium (IUS), 2012 IEEE International}}, issn = {{1948-5719}}, keywords = {{crystallisation, hydrophones, piezoceramics, potassium compounds, powder technology, powders, sensors, sintering, sodium compounds, (K0.48Na0.52)NbO3, KNbO3 powder, NaNbO3 powder, crystallization, energy harvesting devices, g33 constant, hydrophone sensor, hydrothermal lead-free (K0.48Na0.52)NbO3 ceramics, hydrothermal method, piezoelectric applications, sintering, Materials, Transducers}}, pages = {{194--195}}, title = {{{Piezoelectric applications of hydrothermal lead-free (K0.48Na0.52)NbO3 ceramics}}}, doi = {{10.1109/ULTSYM.2012.0048}}, year = {{2012}}, } @article{9743, abstract = {{The hydrothermal method enables the production of high-quality piezoelectric materials. In this study, we propose to irradiate the reaction solutions with ultrasonic power during the hydrothermal method to obtain a shorter reaction time and a smooth film surface. A high-pressure reaction container for the ultrasonic transducer was newly developed, and the ultrasonically-assisted hydrothermal method was examined by using this container. The effect of ultrasonic assist on the synthesis of lead-zirconate-titanate (PZT) thin films and (K,Na)NbO$_{3}$ powders was verified. Thicker PZT film, thickness around 10 ${\mu}$m, could be obtained in one process, and (K,Na)NbO$_{3}$ powder was synthesized in half the previous reaction time.}}, author = {{Ageba, Ryo and Kadota, Yoichi and Maeda, Takafumi and Takiguchi, Norihito and Morita, Takeshi and Ishikawa, Mutsuo and Bornmann, Peter and Hemsel, Tobias}}, issn = {{1948-5719}}, journal = {{Journal of Korean Physical Society}}, keywords = {{Hydrothermal method, High-power ultrasonic, PZT thin film, Lead-free piezoelectric materials}}, number = {{4}}, pages = {{918--923}}, title = {{{Ultrasonically-assisted Hydrothermal Method for Ferroelectric Material Synthesis}}}, doi = {{10.3938/jkps.57.918}}, volume = {{57}}, year = {{2010}}, } @article{9744, abstract = {{Direct ultrasound irradiation is advantageous to increase the efficiency of the hydrothermal method which can be used for the production of piezoelectric thin films and lead free piezoelectric ceramics. To apply ultrasound directly to the process transducer prototypes were developed regarding the boundary conditions of the hydrothermal method. LiNbO$_{3}$ and PIC 181 were proven as feasible materials for high temperature resistant transducers ($\geq 200^\circ C$). Resistance of the transducers horn against the corrosive mineralizer was achieved by using Hastelloy C-22. The efficiency of the ultrasound assisted hydrothermal method depends on the generated sound field. Impedance and sound field measurements have shown that the sound field depends on the filling level and the position and design of the transducer.}}, author = {{Bornmann, Peter and Hemsel, Tobias and Littmann, Walter and Ageba, Ryo and Kadota, Yoishi and Morita, Takeshi}}, issn = {{1948-5719}}, journal = {{Journal of Korean Physical Society}}, keywords = {{High-temperature transducer, Hydrothermal method, Lithium-niobate transducer}}, number = {{4}}, pages = {{1122}}, title = {{{Ultrasonic Transducer for the Hydrothermal Method}}}, doi = {{10.3938/jkps.57.1122}}, volume = {{57}}, year = {{2010}}, } @article{9745, abstract = {{In the modeling of piezoelectric Langevin transducers using usual transfer matrix methods, some simplifications have been adopted. This leads to reduction of the model quality. A mixed transfer matrix method is employed in the modeling of Langevin transducers, where the pre-stressed bolt is modeled as a separate four-pole element, which is connected to other elements in parallel. Based on the mixed transfer matrix method, the four (six)-pole element description of the piezoelectric Langevin transducer is built up and the total transfer matrix relation is derived. The resonance frequencies of the transducer are calculated and then measured using the impedance analyzer (HP4192). Experimental result shows that the mixed transfer matrix method has better modeling quality than the usual transfer matrix method for the vibration analysis of piezoelectric Langevin transducers.}}, author = {{Fu, Bo and Li, Chao and Zhang, Jianming and Huang, Zhenwei and Hemsel, Tobias}}, issn = {{1948-5719}}, journal = {{Journal of Korean Physical Society}}, keywords = {{Piezoelectric langevin transducer, Transfer matrix method, Four (six)-pole element description, Pre-stressed bolt}}, number = {{4}}, pages = {{929}}, title = {{{Modeling of Piezoelectric Langevin Transducers by Using Mixed Transfer Matrix Methods}}}, doi = {{10.3938/jkps.57.929}}, volume = {{57}}, year = {{2010}}, } @article{9749, abstract = {{Piezoelectric materials find wide application in technical systems. Most often, a combination of piezoelectric and other materials is advantageous. The position and the amount of the piezoelectric material within the overall system depends on various aspects like maximum mechanical output to the load, maximum electromechanical efficiency of the system, maximum utilization of the piezoelectric material, minimum self-heating of the piezoelectric material, and controllability of the system, which might be key aspects for the optimisation of the system design. For a composite longitudinal vibrator (bolted Langevin transducer), which is a base for many technical applications, this contribution shows in detail, how above mentioned aspects depend on the position and volume of the piezoelectric material related to the mode shape.}}, author = {{Hemsel, Tobias and Lierk, Ernst Günther and Littmann, Walter and Morita, Takeshi}}, issn = {{1948-5719}}, journal = {{Journal of Korean Physical Society}}, keywords = {{Bolted Langevin transducer, Optimum placement of piezoelectric ceramics}}, number = {{4}}, pages = {{933--937}}, title = {{{Various Aspects of the Placement of a Piezoelectric Material in Composite Actuators, Motors, and Transducers}}}, doi = {{10.3938/jkps.57.933}}, volume = {{57}}, year = {{2010}}, } @article{9751, abstract = {{Piezoelectric inertia motors have a simple construction and are controlled by a single driving signal. This allows for miniaturization and low cost production. One of the main questions to be answered during the design process of a piezoelectric inertia motor is which electrical excitation signal yields optimum motor characteristics. Three signals and their variants are widely used in literature: sawtooth, parabolic and cycloidic signals. It can be shown that neither of these can drive the motor at its maximum possible velocity in non-resonant operation. Within this paper we propose to use a rigid body model of a simple inertia motor to predict the motor characteristics depending on the movement pattern of the driving element. Advantages and disadvantages of three different drive signals that maximize the motor velocity are discussed.}}, author = {{Hunstig, Matthias and Hemsel, Tobias}}, issn = {{1948-5719}}, journal = {{Journal of Korean Physical Society}}, number = {{4}}, pages = {{938--941}}, title = {{{Drive Signals for Maximizing the Velocity of Piezoelectric Inertia Motors}}}, doi = {{10.3938/jkps.57.938}}, volume = {{57}}, year = {{2010}}, } @article{9752, abstract = {{Piezoelectric inertia motors make use of the inertia of a slider to drive the slider by friction contact in a series of small steps which are generally composed of a stick phase and a slip phase. If the best electrical drive signal for the piezoelectric actuator in an inertia motor is to be determined, its dynamical behaviour must be known. A classic dynamic lumped parameter model for piezoelectric actuators is valid only in resonance and, therefore, is not suitable for modelling the actuator in an inertia motor. A reduced dynamic model is used instead. Its parameters are identified using a step response measurement. This model is used to predict the movement of the actuator in response to a velocity-optimized signal introduced in a separate contribution. Results show that the model cannot represent the dynamical characteristics of the actuator completely. For determining voltage signals that let piezoelectric actuators follow a calculated movement pattern exactly, the model can, therefore, only be used with limitations.}}, author = {{Hunstig, Matthias and Hemsel, Tobias}}, issn = {{1948-5719}}, journal = {{Journal of Korean Physical Society}}, number = {{4}}, pages = {{952--954}}, title = {{{Parameter Identification and Model Validation for the Piezoelectric Actuator in an Inertia Motor}}}, doi = {{10.3938/jkps.57.952}}, volume = {{57}}, year = {{2010}}, } @article{9756, abstract = {{Dieser Beitrag fasst die bekannten analytischen Berechnungsmethoden für piezoelektrische Ultraschallverbundschwinger zusammen und gibt anhand typischer Beispiele Anleitungen zur Lösung theoretischer und technischer Fragen bei deren Entwicklung. Zunächst werden die passiven, in der Regel metallischen Komponenten von Verbundschwingern als Stab- oder Plattensysteme mit homogen verteilten Feder-, Masse und Dämpfungseigenschaften beschrieben. Hier breitet sich die Schwingungsenergie in Form stehender und fortschreitender Wellen zum akustischen Verbraucher hin aus. Es folgt eine gleichwertige und schaltungstreue Darstellung durch elektrische oder mechanische Vierpole, die für den Entwicklungsingenieur leichter zu handhaben sind und in Netzwerken direkt mit Masons Ersatzschaltung des piezoelektrischen Wandlers gekoppelt werden können. Danach werden die wichtigsten, messtechnisch zugänglichen Parameter anhand eines in Resonanznähe zulässigen Ersatzmodells mit konzentrierten elektrischen bzw. mechanischen Komponenten definiert. Als Schwerpunkt wird anschließend deren analytische Berechnung und messtechnische Verifizierung an typischen Beispielen demonstriert. Es folgen wichtige technische Informationen über Frequenzkorrekturen, Schallgeschwindigkeitsdispersion, Leistungs- und Belastbarkeitsgrenzen der Komponenten und andere wertvolle praktische Hinweise.}}, author = {{Lierke, Ernst-Günter and Littmann, Walter and Hemsel, Tobias}}, issn = {{1948-5719}}, journal = {{Veröffentlichung der Universität Paderborn}}, title = {{{Zur Theorie der piezoelektrischen Ultraschallverbundschwinger mit praktischen Schlussfolgerungen für den Entwicklungsingenieur}}}, year = {{2010}}, } @article{9757, author = {{Lucinskis, Raimundas and Mazeika, Dalius and Hemsel, Tobias and Bansevicius, Ramutis}}, issn = {{1948-5719}}, journal = {{MECHANIKA}}, title = {{{The experimental research of piezoelectric actuator with two vectors of polarization direction}}}, year = {{2010}}, } @article{9758, abstract = {{As a lead-free piezoelectric ceramics, (K,Na)NbO$_{3}$ is a promising material because of its good piezoelectric properties. In this study, (K$_{1-x}$Na$_{x}$)NbO$_{3}$ ceramics were synthesized from a KNbO$_{3}$ and NaNbO$_{3}$ mixture powder prepared by the hydrothermal reaction. The hydrothermal reaction enables the production of high quality powder for the ceramics fabrication process. To obtain (K$_{1-x}$Na$_{x}$)NbO$_{3}$ ceramics, these two powders KNbO$_{3}$ and NaNbO$_{3}$ were mixed and then sintered together. X-Ray diffraction analysis revealed that the solid solution ceramics (K$_{1-x}$Na$_{x}$)NbO$_{3}$ was produced by the sintering process. The K/Na ratio in (K$_{1-x}$Na$_{x}$)NbO$_{3}$ ceramics was optimized for the best piezoelectric properties. The optimized forms was (K$_{0.48}$Na$_{0.52}$)NbO$_{3}$, which showed the following piezoelectric properties; k$_{33}$=0.56, d$_{33}$=114pC/N. In addition, the ferroelectric properties, P$_{r}$=7.72mC/cm$^{2}$, E$_{c}$=857V/mm, and the Curie temperature T$_{c}$=420$_{o}$C were also measured.}}, author = {{Maeda, Takafumi and Takiguchi, Norihito and Morita, Takeshi and Ishikawa, Mutsuo and Hemsel, Tobias}}, issn = {{1948-5719}}, journal = {{Journal of Korean Physical Society}}, keywords = {{Lead-free piezoelectric material, KNN, Hydrothermal method}}, number = {{4}}, pages = {{924--928}}, title = {{{Hydrothermal (K1-xNax)NbO3 Lead-free Piezoelectric Ceramics}}}, doi = {{10.3938/jkps.57.924}}, volume = {{57}}, year = {{2010}}, } @article{9759, abstract = {{Among various lead-free piezoelectric materials, (K,Na)NbO$_{3}$ is a very promising candidate. In this study, (K,Na)NbO$_{3}$ ceramics were sintered from mixed (K,Na)NbO$_{3}$ and NaNbO$_{3}$ powders prepared by hydrothermal reaction. These two powders were mixed with distilled water in a KNbO$_{3}$/NaNbO$_{3}$ molar ratio of 1. After sintering the mixed powder, the solid solution of (Na,K)NbO$_{3}$ ceramics was obtained. The electrical properties such as the electromechanical coupling factors k$_{p}$ and k$_{33}$, the mechanical quality factor, Q$_{m}$, and the piezoelectric constant d$_{33}$ of the sintered (K,Na)NbO$_{3}$ ceramics were 0.32, 0.48, 71 (radial mode), 118 ((33)mode), and 107 pC/N, respectively.}}, author = {{Maeda, Takafumi and Takiguchi, Norihito and Morita, Takeshi and Ishikawa, Mutsuo and Hemsel, Tobias}}, issn = {{1948-5719}}, journal = {{Materials Letters}}, keywords = {{Lead-free piezoelectric material, (K, Na)NbO$_{3}$ ceramics, Sintering solid solution, Piezoelectric properties}}, number = {{2}}, pages = {{125--128}}, title = {{{(K,Na)NbO3 lead-free piezoelectric ceramics synthesized from hydrothermal powders}}}, doi = {{10.1016/j.matlet.2009.10.012}}, volume = {{64}}, year = {{2010}}, } @inproceedings{9735, abstract = {{Die Entwicklung piezoelektrischer Tr{\"a}gheitsmotoren basiert derzeit auf Erfahrungswissen und Prototypenbau. Es existiert kein allgemeines Modell und keine Methodik f{\"u}r die systematische Entwicklung dieser Motoren. In diesem Beitrag stellen wir einen Ansatz zur Entwicklung einer solchen Methodik und den von uns aufgebauten Versuchsmotor vor. Der Motor ist modular aufgebaut; er besteht im Wesentlichen aus einer piezoelektrischen Antriebseinheit, einem Antriebsstab und dem zu bewegenden Schlitten. Eine wesentliche Aufgabe bei der modellbasierten Entwicklung von Tr{\"a}gheitsmotoren ist die hinreichende Beschreibung des dynamischen Verhaltens der Antriebseinheit. Um ein geeignetes Modell zu finden, bzw. um nachzuweisen, dass einfache parametrische Modelle gen{\"u}gen, wird die Antriebseinheit des Motors detailliert untersucht. Es zeigt sich, dass der derzeitige Aufbau eine Reihe von Nachteilen aufweist, die durch eine teilweise Neukonstruktion der Antriebseinheit beseitigt oder zumindest entsch{\"a}rft werden k{\"o}nnen.}}, author = {{Hunstig, Matthias and Hemsel, Tobias}}, booktitle = {{6. Paderborner Workshop Entwurf mechatronischer Systeme}}, editor = {{Gausemeier, Jürgen and Rammig, Franz and Schäfer, Wilhelm and Trächtler, Ansgar}}, issn = {{1948-5719}}, keywords = {{Piezoelektrischer Tr{\}}, pages = {{85--96}}, publisher = {{Heinz Nixdorf Institut, Universität Paderborn}}, title = {{{Modellbasierte Entwicklung piezoelektrischer Trägheitsmotoren}}}, volume = {{250}}, year = {{2009}}, }