--- _id: '66428' author: - first_name: Markus Daniel full_name: Dohmen, Markus Daniel id: '69217' last_name: Dohmen - first_name: Peter full_name: Bornmann, Peter last_name: Bornmann - first_name: 'Walter ' full_name: 'Littmann, Walter ' last_name: Littmann - first_name: Tobias full_name: Hemsel, Tobias id: '210' last_name: Hemsel - first_name: Walter full_name: Sextro, Walter id: '21220' last_name: Sextro citation: ama: Dohmen MD, Bornmann P, Littmann W, Hemsel T, Sextro W. Modellgestützte Optimierung eines Ultraschall-Torsionsschweißsystems. PLUS-Elektronikfertigung. 2026:432-435. apa: Dohmen, M. D., Bornmann, P., Littmann, W., Hemsel, T., & Sextro, W. (2026). Modellgestützte Optimierung eines Ultraschall-Torsionsschweißsystems. PLUS-Elektronikfertigung, 04/2026, 432–435. bibtex: '@article{Dohmen_Bornmann_Littmann_Hemsel_Sextro_2026, title={Modellgestützte Optimierung eines Ultraschall-Torsionsschweißsystems}, number={04/2026}, journal={PLUS-Elektronikfertigung}, author={Dohmen, Markus Daniel and Bornmann, Peter and Littmann, Walter and Hemsel, Tobias and Sextro, Walter}, year={2026}, pages={432–435} }' chicago: Dohmen, Markus Daniel, Peter Bornmann, Walter Littmann, Tobias Hemsel, and Walter Sextro. “Modellgestützte Optimierung eines Ultraschall-Torsionsschweißsystems.” PLUS-Elektronikfertigung, 2026. ieee: M. D. Dohmen, P. Bornmann, W. Littmann, T. Hemsel, and W. Sextro, “Modellgestützte Optimierung eines Ultraschall-Torsionsschweißsystems,” PLUS-Elektronikfertigung, no. 04/2026, pp. 432–435, 2026. mla: Dohmen, Markus Daniel, et al. “Modellgestützte Optimierung eines Ultraschall-Torsionsschweißsystems.” PLUS-Elektronikfertigung, no. 04/2026, 2026, pp. 432–35. short: M.D. Dohmen, P. Bornmann, W. Littmann, T. Hemsel, W. Sextro, PLUS-Elektronikfertigung (2026) 432–435. date_created: 2026-07-10T07:57:12Z date_updated: 2026-07-10T08:01:40Z issue: 04/2026 language: - iso: ger page: 432-435 publication: PLUS-Elektronikfertigung publication_date: 2026-04 publication_status: published status: public title: Modellgestützte Optimierung eines Ultraschall-Torsionsschweißsystems type: newspaper_article user_id: '69217' year: '2026' ... --- _id: '58510' abstract: - lang: eng text: 'Today’s ultrasonic transducers find broad application in diverse technology branches and most often cannot be replaced by other actuators. They are typically based on lead-containing piezoelectric ceramics. These should be replaced for environmental and health issues by lead-free alternatives. Multiple material alternatives are already known, but there is a lack of information about their technological readiness level. To fill this gap, a small series of prestressed longitudinally vibrating transducers was set up with a standard PZT material and two lead-free variants within this study. The entire process for building the transducers is documented: characteristics of individual ring ceramics, burn-in results, and free vibration and characteristics under load are shown. The main result is that the investigated lead-free materials are ready to use within ultrasonic bolted Langevin transducers (BLTs) for medium-power applications, when the geometrical setup of the transducer is adopted. Since lead-free ceramics need higher voltages to achieve the same power level, the driving electronics or the mechanical setup must be altered specifically for each material. Lower self-heating of the lead-free materials might be attractive for heat-sensitive processes.' article_number: '55' article_type: original author: - first_name: Claus full_name: Scheidemann, Claus id: '38259' last_name: Scheidemann - first_name: Peter full_name: Bornmann, Peter last_name: Bornmann - first_name: Walter full_name: Littmann, Walter last_name: Littmann - first_name: Tobias full_name: Hemsel, Tobias id: '210' last_name: Hemsel citation: ama: Scheidemann C, Bornmann P, Littmann W, Hemsel T. Lead-Free Ceramics in Prestressed Ultrasonic Transducers. Actuators. 2025;14(2). doi:10.3390/act14020055 apa: Scheidemann, C., Bornmann, P., Littmann, W., & Hemsel, T. (2025). Lead-Free Ceramics in Prestressed Ultrasonic Transducers. Actuators, 14(2), Article 55. https://doi.org/10.3390/act14020055 bibtex: '@article{Scheidemann_Bornmann_Littmann_Hemsel_2025, title={Lead-Free Ceramics in Prestressed Ultrasonic Transducers}, volume={14}, DOI={10.3390/act14020055}, number={255}, journal={Actuators}, publisher={MDPI AG}, author={Scheidemann, Claus and Bornmann, Peter and Littmann, Walter and Hemsel, Tobias}, year={2025} }' chicago: Scheidemann, Claus, Peter Bornmann, Walter Littmann, and Tobias Hemsel. “Lead-Free Ceramics in Prestressed Ultrasonic Transducers.” Actuators 14, no. 2 (2025). https://doi.org/10.3390/act14020055. ieee: 'C. Scheidemann, P. Bornmann, W. Littmann, and T. Hemsel, “Lead-Free Ceramics in Prestressed Ultrasonic Transducers,” Actuators, vol. 14, no. 2, Art. no. 55, 2025, doi: 10.3390/act14020055.' mla: Scheidemann, Claus, et al. “Lead-Free Ceramics in Prestressed Ultrasonic Transducers.” Actuators, vol. 14, no. 2, 55, MDPI AG, 2025, doi:10.3390/act14020055. short: C. Scheidemann, P. Bornmann, W. Littmann, T. Hemsel, Actuators 14 (2025). date_created: 2025-02-04T13:43:23Z date_updated: 2025-02-04T13:46:41Z department: - _id: '151' doi: 10.3390/act14020055 intvolume: ' 14' issue: '2' language: - iso: eng main_file_link: - open_access: '1' url: https://www.mdpi.com/2076-0825/14/2/55 oa: '1' publication: Actuators publication_identifier: issn: - 2076-0825 publication_status: published publisher: MDPI AG quality_controlled: '1' status: public title: Lead-Free Ceramics in Prestressed Ultrasonic Transducers type: journal_article user_id: '210' volume: 14 year: '2025' ... --- _id: '64798' abstract: - lang: eng text: "Lead-containing piezoelectric ceramics are still the base for today’s ultrasonic transducers used in broad applications. This is partly due to missing powerful lead-free piezoelectric ceramic parts in the commercial market. There has been much research on lead-free materials but developing them into marketable parts seems to be an ongoing process. The actual exemption of ROHS has expired, but as the new exemption has already been requested, ceramic suppliers keep on selling lead containing products. Nevertheless, these should be replaced by lead-free alternatives for environmental and health issues. \r\nThis contribution focuses on exploring the technological readiness level of lead-free hard piezoceramics for prestressed ultrasonic transducers. A small series of bolted Langevin transducers was set up with standard PZT material and three commercial lead-free variants. Results of the building process from individual ring ceramic characteristics to transducer load tests are presented. The main finding of this study is that the lead-free materials technically can compete with the standard PZT for medium-power applications. Some adaptations in the ultrasonic system must be done: the geometry must be altered to fit resonance frequency, and higher voltages or thinner ceramics are needed to achieve the same vibration level at low load. For reaching same power, the volume of lead-free ceramics must be 1.5 to 3 times larger. As already promoted in literature, mechanical losses at high vibration levels are smaller for the lead-free materials. This might help to argument lead-free piezoelectric materials in some applications.\r\n\r\nReferences\r\n1.\tDirective 2011/65/EU of the European Parliament and of the Council of 8 June 2011 on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment. EUR-Lex Document 02011L0065-20240801. Available online: http://data.europa.eu/eli/dir/2011/65/2024-08-01 (accessed on 24 January 2025).\r\n2.\tLangevin, P. (1918) Method and Apparatus for Transmitting and Receiving Submarine Elastic Waves Using the Piezoelectric Properties of Quartz. French Patent Office; Patent No. FR505703.\r\n3.\tHemsel, T.; Twiefel, J. (2023) Piezoelectric Ultrasonic Power Transducers. In Encyclopedia of Materials: Electronics; Academic Press: Oxford, UK; pp. 276–285. https://doi.org/10.1016/b978-0-12-819728-8.00047-4.\r\n4.\tATHENA Technologie Beratung GmbH (2025) Description of Ultrasound Generator. Available online: http://shop.myathena.de/epages/12074748.sf/de_DE/?ObjectPath=/Shops/12074748/Products/AM200 (accessed on 13 January 2025).\r\n5.\tLittmann, W.; Hemsel, T.; Kauczor, C.; Wallaschek, J.; Sinha, W. (2003) Load-adaptive phase-controller for resonant driven piezoelectric devices. Proc. World Congr. Ultrason. 2003, 48, 547–550.\r\n6.\tScheidemann, C., Bornmann, P., Littmann, W., & Hemsel, T. (2025). Lead-Free Ceramics in Prestressed Ultrasonic Transducers. Actuators, 14(2), 55. https://doi.org/10.3390/act14020055\r\n" author: - first_name: Claus full_name: Scheidemann, Claus id: '38259' last_name: Scheidemann - first_name: Peter full_name: Bornmann, Peter last_name: Bornmann - first_name: Walter full_name: Littmann, Walter last_name: Littmann - first_name: Tobias full_name: Hemsel, Tobias id: '210' last_name: Hemsel citation: ama: 'Scheidemann C, Bornmann P, Littmann W, Hemsel T. Bolted Langevin transducers with leadfree piezoelectric ceramics. In: ; 2025.' apa: Scheidemann, C., Bornmann, P., Littmann, W., & Hemsel, T. (2025). Bolted Langevin transducers with leadfree piezoelectric ceramics. International Workshop on Piezoelectric Materials and Applications in Actuators (IWPMA), Vilnius, Lithuania. bibtex: '@inproceedings{Scheidemann_Bornmann_Littmann_Hemsel_2025, title={Bolted Langevin transducers with leadfree piezoelectric ceramics}, author={Scheidemann, Claus and Bornmann, Peter and Littmann, Walter and Hemsel, Tobias}, year={2025} }' chicago: Scheidemann, Claus, Peter Bornmann, Walter Littmann, and Tobias Hemsel. “Bolted Langevin Transducers with Leadfree Piezoelectric Ceramics,” 2025. ieee: C. Scheidemann, P. Bornmann, W. Littmann, and T. Hemsel, “Bolted Langevin transducers with leadfree piezoelectric ceramics,” presented at the International Workshop on Piezoelectric Materials and Applications in Actuators (IWPMA), Vilnius, Lithuania, 2025. mla: Scheidemann, Claus, et al. Bolted Langevin Transducers with Leadfree Piezoelectric Ceramics. 2025. short: 'C. Scheidemann, P. Bornmann, W. Littmann, T. Hemsel, in: 2025.' conference: end_date: 2025-07-03 location: Vilnius, Lithuania name: International Workshop on Piezoelectric Materials and Applications in Actuators (IWPMA) start_date: 2025-07-01 date_created: 2026-03-02T10:39:40Z date_updated: 2026-03-02T11:04:56Z ddc: - '620' department: - _id: '151' file: - access_level: open_access content_type: application/pdf creator: hemsel date_created: 2026-03-02T10:37:46Z date_updated: 2026-03-02T11:00:37Z file_id: '64799' file_name: IWPMA_2025_Hemsel.pdf file_size: 1812289 relation: main_file file_date_updated: 2026-03-02T11:00:37Z has_accepted_license: '1' keyword: - lead free piezoelectric ceramics - bolted Langevin transducer - medium power ultrasound. language: - iso: eng oa: '1' status: public title: Bolted Langevin transducers with leadfree piezoelectric ceramics type: conference user_id: '210' year: '2025' ... --- _id: '64800' abstract: - lang: eng text: "Intensive ultrasonic cleaning of surfaces by means of a lead-free ultrasonic transducer with focusing sonotrode\r\nUltrasonic cleaning baths are probably a coincidental development: After underwater sonars had already been successfully used to detect submarines before 1920, it was probably observed in this environment that the ultrasonic oscillators not only showed a self-cleaning effect but also cavitation damage. At the beginning of the 1950s, the first ultrasonic cleaning devices finally came onto the market. Today, the range of applications ranges from household appliances for jewellery and eyewear cleaning to classic cleaning baths for metal parts and systems for cleaning highly sensitive electronic components. There is a certain gap in handheld, mobile cleaning equipment. Although devices for spot cleaning of textiles are known, the cleaning effect is usually low. \r\nDue to the directive 2011/65/EU on the restriction of the use of hazardous substances in electrical and electronic equipment (RoHS) [1] lead should no longer be used in technical devices. As today’s standard ceramics for medium and high-power ultrasonic transducers typically contain lead, there is a need to explore the use of lead-free ceramics in this field. Honda [2] already offers a cleaning transducer based on lead-free piezoelectric ceramics, but it is designed to be used in cleaning baths.\r\nThis article presents the model-based development of a highly innovative ultrasonic cleaner. On the one hand, lead-free piezoelectric ceramics are used, and on the other hand, a special sonotrode has been developed that concentrates the sound in such a way that a strong cavitation and thus cleaning effect is achieved with comparatively low power in a short time. Coupled field finite element method was used to find an appropriate geometry for the focussing sonotrode. The comparison of simulation and measurement results shows that the lead-free piezoceramics used do their job well and can keep up with standard ceramics, but more ceramic volume is needed to achieve same power. An advanced control concept was elaborated to ensure continuous hard cavitation at varying distances between the sonotrode and the part to be cleaned. Cleaning results for different surfaces and contaminations are presented. The concept of the focusing sonotrode shows that a convincing cleaning result can be achieved even with low power and in short time, provided that the oscillation system and control electronics are suitably coordinated.\r\n\r\nReferences\r\n[1] http://data.europa.eu/eli/dir/2011/65/2024-08-01 \r\n[2] https://en.honda-el.co.jp/product/ceramics/lineup/lead_off/lead-off \r\n" author: - first_name: Tobias full_name: Hemsel, Tobias id: '210' last_name: Hemsel - first_name: Claus full_name: Scheidemann, Claus id: '38259' last_name: Scheidemann - first_name: Peter full_name: Bornmann, Peter last_name: Bornmann - first_name: Walter full_name: Littmann, Walter last_name: Littmann - first_name: Walter full_name: Sextro, Walter id: '21220' last_name: Sextro citation: ama: 'Hemsel T, Scheidemann C, Bornmann P, Littmann W, Sextro W. Intensive ultrasonic cleaning of surfaces by means of lead-free ultrasonic transducer with focussing sonotrode. In: ; 2025.' apa: Hemsel, T., Scheidemann, C., Bornmann, P., Littmann, W., & Sextro, W. (2025). Intensive ultrasonic cleaning of surfaces by means of lead-free ultrasonic transducer with focussing sonotrode. International Congress on Ultrasonics (ICU), Paderborn, Germany. bibtex: '@inproceedings{Hemsel_Scheidemann_Bornmann_Littmann_Sextro_2025, title={Intensive ultrasonic cleaning of surfaces by means of lead-free ultrasonic transducer with focussing sonotrode}, author={Hemsel, Tobias and Scheidemann, Claus and Bornmann, Peter and Littmann, Walter and Sextro, Walter}, year={2025} }' chicago: Hemsel, Tobias, Claus Scheidemann, Peter Bornmann, Walter Littmann, and Walter Sextro. “Intensive Ultrasonic Cleaning of Surfaces by Means of Lead-Free Ultrasonic Transducer with Focussing Sonotrode,” 2025. ieee: T. Hemsel, C. Scheidemann, P. Bornmann, W. Littmann, and W. Sextro, “Intensive ultrasonic cleaning of surfaces by means of lead-free ultrasonic transducer with focussing sonotrode,” presented at the International Congress on Ultrasonics (ICU), Paderborn, Germany, 2025. mla: Hemsel, Tobias, et al. Intensive Ultrasonic Cleaning of Surfaces by Means of Lead-Free Ultrasonic Transducer with Focussing Sonotrode. 2025. short: 'T. Hemsel, C. Scheidemann, P. Bornmann, W. Littmann, W. Sextro, in: 2025.' conference: end_date: 2025-09-25 location: Paderborn, Germany name: International Congress on Ultrasonics (ICU) start_date: 2025-09-21 date_created: 2026-03-02T10:47:48Z date_updated: 2026-03-02T10:58:37Z ddc: - '620' department: - _id: '151' file: - access_level: open_access content_type: application/pdf creator: hemsel date_created: 2026-03-02T10:46:43Z date_updated: 2026-03-02T10:58:37Z file_id: '64801' file_name: ICU_2025_Hemsel.pdf file_size: 1946202 relation: main_file file_date_updated: 2026-03-02T10:58:37Z has_accepted_license: '1' language: - iso: eng oa: '1' status: public title: Intensive ultrasonic cleaning of surfaces by means of lead-free ultrasonic transducer with focussing sonotrode type: conference user_id: '210' year: '2025' ... --- _id: '64804' abstract: - lang: ger text: "Das Ultraschallschweißen ist in der Verpackungs-, Halbleiter- und Automobilindustrie weit verbreitet. Neben dem Schweißen von Blechen bietet es die Möglichkeit, Folien oder Hülsen zu verschweißen. Konventionelle Schweißsysteme arbeiten mit Längs- oder Biegeschwingungen, deren Hauptanteil in der Schweißebene liegt. Der orthogonale Anteil verursacht zusätzliche Belastungen im Schweißgut. Bei der Verwendung von Torsionsschwingungen wird die orthogonale Komponente der Schwingung nahezu eliminiert. \r\nIn diesem Beitrag wird ein System vorgestellt, bei dem die Torsionsschwingung durch tangentiale Polarisation der Piezokeramiken erzeugt wird. Der Transducer ist axial oberhalb des Schweißpunktes platziert, sodass die Normalkraft momentfrei aufgebracht wird. Das Schweißwerkzeug weicht beim Schweißvorgang daher seitlich nicht aus. Zudem wird das Schweißen an schwer zugänglichen Positionen vereinfacht, da der Systemaufbau deutlich schlanker ist als konventionelle Ultraschallschweißsysteme.\r\nDie Auslegung des Torsionsschwingsystems stellt eine Herausforderung dar. Insbesondere muss die Lagerung des Schwingers betrachtet werden, da diese die Normalkraft übertragen und zugleich die Schwingung nicht beeinträchtigen soll. Der Schweißprozess bewirkt eine Verschiebung von Schwingungsknoten und Resonanzfrequenzen. Im Rahmen des Vortrags wird ein Finite-Elemente-Simulationsmodell vorgestellt, das in Kombination mit einem Lastmodell das Systemverhalten während des Schweißprozesses abbildet. Die Geometrie des Transducers wurde schrittweise so angepasst, dass die Schwingamplitude im Lagerungspunkt minimiert wird. \r\n" author: - first_name: Markus Daniel full_name: Dohmen, Markus Daniel id: '69217' last_name: Dohmen - first_name: Peter full_name: Bornmann, Peter last_name: Bornmann - first_name: Walter full_name: Littmann, Walter last_name: Littmann - first_name: Tobias full_name: Hemsel, Tobias id: '210' last_name: Hemsel - first_name: Walter full_name: Sextro, Walter id: '21220' last_name: Sextro citation: ama: 'Dohmen MD, Bornmann P, Littmann W, Hemsel T, Sextro W. Modellgestützte Optimierung eines Ultraschall-Torsionsschweißsystems. In: ; 2025.' apa: Dohmen, M. D., Bornmann, P., Littmann, W., Hemsel, T., & Sextro, W. (2025). Modellgestützte Optimierung eines Ultraschall-Torsionsschweißsystems. bibtex: '@inproceedings{Dohmen_Bornmann_Littmann_Hemsel_Sextro_2025, title={Modellgestützte Optimierung eines Ultraschall-Torsionsschweißsystems}, author={Dohmen, Markus Daniel and Bornmann, Peter and Littmann, Walter and Hemsel, Tobias and Sextro, Walter}, year={2025} }' chicago: Dohmen, Markus Daniel, Peter Bornmann, Walter Littmann, Tobias Hemsel, and Walter Sextro. “Modellgestützte Optimierung Eines Ultraschall-Torsionsschweißsystems,” 2025. ieee: M. D. Dohmen, P. Bornmann, W. Littmann, T. Hemsel, and W. Sextro, “Modellgestützte Optimierung eines Ultraschall-Torsionsschweißsystems,” 2025. mla: Dohmen, Markus Daniel, et al. Modellgestützte Optimierung Eines Ultraschall-Torsionsschweißsystems. 2025. short: 'M.D. Dohmen, P. Bornmann, W. Littmann, T. Hemsel, W. Sextro, in: 2025.' date_created: 2026-03-02T12:02:08Z date_updated: 2026-03-03T13:57:25Z ddc: - '620' department: - _id: '151' file: - access_level: closed content_type: application/pdf creator: hemsel date_created: 2026-03-02T12:01:28Z date_updated: 2026-03-02T12:01:28Z file_id: '64805' file_name: Dohmen_UPB_LDM_IMAPS_2025.pdf file_size: 1912154 relation: main_file success: 1 file_date_updated: 2026-03-02T12:01:28Z has_accepted_license: '1' language: - iso: eng status: public title: Modellgestützte Optimierung eines Ultraschall-Torsionsschweißsystems type: conference user_id: '210' year: '2025' ... --- _id: '64803' abstract: - lang: eng text: "Nowadays ultrasound technology is established in various fields of application like industrial production or medical technology. Besides high power ultrasound applications like ultrasonic cleaning and ultrasonic welding, which are often not strongly restricted regarding their weight, costs, and construction space, there are many applications in the low to medium power range like handheld surgical instruments, medical inhalers, or ultrasonic cutters. For the latter there is often a strong demand for low weight and construction space and low costs to be competitive in mass production. Another challenge that arises from the RoHS-directive [1] is, that new ultrasonic devices should avoid the use of lead-containing PZT-materials. Against this background there is a demand for lead-free, small and lightweight and cost-effective ultrasonic transducers.\r\nIn many of the above-mentioned applications, pre-stressed Bolted-Langevine-Transducers (BLT) based on lead-containing PZT-materials are established to generate ultrasonic vibrations. These are quite advantageous in many ways and can be built tailored to each application and even for high power of thousands of watts. But due to the required steps during their manufacturing process (machining parts, assembly, pre-stressing, frequency tuning, …), these transducers remain expensive. Furthermore, due to the operation in resonance, the construction space of these transducers is linked to their wavelength and cannot be reduced remarkably.\r\nFor these reasons, our aim is to present an innovative lead-free ultrasonic transducer for low to medium power applications, that is based on bending vibrations instead of longitudinal vibrations. This design enables to build very small transducers. Furthermore, due to their simple construction, these transducers can be built at low manufacturing costs and are well suited for industrial mass production. The use of lead-free piezoelectric materials makes this transducer design ready for future applications.\r\nIn our contribution we will present the model-based design of a lead-free 30 kHz bending transducer for applications up to 10 W. Furthermore, the comprehensive experimental analysis of this transducer-prototype in applications like mist generation or ultrasonic drilling will be presented. The results will be compared to a PZT-based bending transducer and a classical BLT to show the potential and limits of these kind of transducers and lead-free materials.\r\n" author: - first_name: Peter full_name: Bornmann, Peter last_name: Bornmann - first_name: Walter full_name: Littmann, Walter last_name: Littmann - first_name: Claus full_name: Scheidemann, Claus id: '38259' last_name: Scheidemann - first_name: Tobias full_name: Hemsel, Tobias id: '210' last_name: Hemsel citation: ama: 'Bornmann P, Littmann W, Scheidemann C, Hemsel T. Innovative lead-free ultrasonic bending transducers for low to medium power applications. In: ; 2025.' apa: Bornmann, P., Littmann, W., Scheidemann, C., & Hemsel, T. (2025). Innovative lead-free ultrasonic bending transducers for low to medium power applications. International Congress on Ultrasonics (ICU), Paderborn, Germany. bibtex: '@inproceedings{Bornmann_Littmann_Scheidemann_Hemsel_2025, title={Innovative lead-free ultrasonic bending transducers for low to medium power applications}, author={Bornmann, Peter and Littmann, Walter and Scheidemann, Claus and Hemsel, Tobias}, year={2025} }' chicago: Bornmann, Peter, Walter Littmann, Claus Scheidemann, and Tobias Hemsel. “Innovative Lead-Free Ultrasonic Bending Transducers for Low to Medium Power Applications,” 2025. ieee: P. Bornmann, W. Littmann, C. Scheidemann, and T. Hemsel, “Innovative lead-free ultrasonic bending transducers for low to medium power applications,” presented at the International Congress on Ultrasonics (ICU), Paderborn, Germany, 2025. mla: Bornmann, Peter, et al. Innovative Lead-Free Ultrasonic Bending Transducers for Low to Medium Power Applications. 2025. short: 'P. Bornmann, W. Littmann, C. Scheidemann, T. Hemsel, in: 2025.' conference: end_date: 2025-09-25 location: Paderborn, Germany name: International Congress on Ultrasonics (ICU) start_date: 2025-09-21 date_created: 2026-03-02T11:35:33Z date_updated: 2026-04-02T12:47:18Z ddc: - '620' department: - _id: '151' file: - access_level: closed content_type: application/pdf creator: hemsel date_created: 2026-04-02T12:46:09Z date_updated: 2026-04-02T12:46:09Z file_id: '65354' file_name: ICU_2025_Bornmann.pdf file_size: 1878995 relation: main_file success: 1 file_date_updated: 2026-04-02T12:46:09Z has_accepted_license: '1' language: - iso: eng status: public title: Innovative lead-free ultrasonic bending transducers for low to medium power applications type: conference user_id: '210' year: '2025' ... --- _id: '64802' abstract: - lang: eng text: Power ultrasonic actuators are used in various industrial, automotive and medical applications. Examples are ultrasonic welding of plastics or metal, surgery processes like cutting of tissue or bone, and the excitation of cavitation in liquids for ultrasonic cleaning. From a physical point of view, many of these processes are characterised by non-constant damping conditions for the ultrasonic actuators, since the systems need to be driven in unloaded as well as in high-loaded states. To get high power output, the piezoelectric actuators are usually driven in or near resonance at precisely defined vibration amplitudes. This is a quite complicated task especially if cost or mass optimized PZT transducers are used or if lead-free piezoelectric ceramics are applied to replace lead-containing materials. In particular the sudden change between loading states is very challenging for electronic excitation and control. The present contribution gives insight into typical problems that may arise in context with sudden load-changes during operation, e.g. uncontrolled jumps in voltage and velocity amplitudes. Measurements on ultrasonic power actuators being abruptly immersed into water at high amplitude are discussed for illustration. Observations during spontaneous load-changes are explained, and it is shown that several problems may be defused by driving the actuators in antiresonance or using a particular driving point in-between resonance and antiresonance (“falling edge control”). The different control strategies are investigated always using just one single hardware. author: - first_name: Walter full_name: Littmann, Walter last_name: Littmann - first_name: Peter full_name: Bornmann, Peter last_name: Bornmann - first_name: Tobias full_name: Hemsel, Tobias id: '210' last_name: Hemsel - first_name: Claus full_name: Scheidemann, Claus id: '38259' last_name: Scheidemann citation: ama: 'Littmann W, Bornmann P, Hemsel T, Scheidemann C. Power ultrasonic actuators with suddenly changing loads: How to control the amplitudes in resonance,  antiresonance, or in-between. In: ; 2025.' apa: 'Littmann, W., Bornmann, P., Hemsel, T., & Scheidemann, C. (2025). Power ultrasonic actuators with suddenly changing loads: How to control the amplitudes in resonance,  antiresonance, or in-between. International Conference on Ultrasonics (ICU), Paderborn, Germany.' bibtex: '@inproceedings{Littmann_Bornmann_Hemsel_Scheidemann_2025, title={Power ultrasonic actuators with suddenly changing loads: How to control the amplitudes in resonance,  antiresonance, or in-between}, author={Littmann, Walter and Bornmann, Peter and Hemsel, Tobias and Scheidemann, Claus}, year={2025} }' chicago: 'Littmann, Walter, Peter Bornmann, Tobias Hemsel, and Claus Scheidemann. “Power Ultrasonic Actuators with Suddenly Changing Loads: How to Control the Amplitudes in Resonance,  Antiresonance, or in-Between,” 2025.' ieee: 'W. Littmann, P. Bornmann, T. Hemsel, and C. Scheidemann, “Power ultrasonic actuators with suddenly changing loads: How to control the amplitudes in resonance,  antiresonance, or in-between,” presented at the International Conference on Ultrasonics (ICU), Paderborn, Germany, 2025.' mla: 'Littmann, Walter, et al. Power Ultrasonic Actuators with Suddenly Changing Loads: How to Control the Amplitudes in Resonance,  Antiresonance, or in-Between. 2025.' short: 'W. Littmann, P. Bornmann, T. Hemsel, C. Scheidemann, in: 2025.' conference: end_date: 2025-09-25 location: Paderborn, Germany name: International Conference on Ultrasonics (ICU) start_date: 2025-09-21 date_created: 2026-03-02T11:19:46Z date_updated: 2026-04-02T12:45:42Z ddc: - '620' department: - _id: '151' file: - access_level: closed content_type: application/pdf creator: hemsel date_created: 2026-04-02T12:41:08Z date_updated: 2026-04-02T12:41:08Z file_id: '65353' file_name: ICU_2025_Littmann.pdf file_size: 2522135 relation: main_file success: 1 file_date_updated: 2026-04-02T12:41:08Z has_accepted_license: '1' language: - iso: eng status: public title: 'Power ultrasonic actuators with suddenly changing loads: How to control the amplitudes in resonance, antiresonance, or in-between' type: conference user_id: '210' year: '2025' ... --- _id: '14852' abstract: - lang: eng text: In a variety of industrial applications, liquids are atomized to produce aerosols for further processing. Example applications are the coating of surfaces with paints, the application of ultra-thin adhesive layers and the atomization of fuels for the production of combustible dispersions. In this publication different atomizing principles (standing-wave, capillary-wave, vibrating-mesh) are examined and discussed. Using an optimized standing-wave system, tough liquids with viscosities of up to about 100 Pas could be successfully atomized. author: - first_name: Paul full_name: Dunst, Paul id: '22130' last_name: Dunst - first_name: Peter full_name: Bornmann, Peter last_name: Bornmann - first_name: Tobias full_name: Hemsel, Tobias id: '210' last_name: Hemsel - first_name: 'Walter ' full_name: 'Littmann, Walter ' last_name: Littmann - first_name: Walter full_name: Sextro, Walter id: '21220' last_name: Sextro citation: ama: 'Dunst P, Bornmann P, Hemsel T, Littmann W, Sextro W. Atomization of Fluids with Ultrasound. In: Lötters J, Urban G, eds. Conference Proceedings - The 4th Conference on MicroFluidic Handling Systems (MFHS2019). Enschede, The Netherlands; 2019:140-143.' apa: Dunst, P., Bornmann, P., Hemsel, T., Littmann, W., & Sextro, W. (2019). Atomization of Fluids with Ultrasound. In J. Lötters & G. Urban (Eds.), Conference Proceedings - The 4th Conference on MicroFluidic Handling Systems (MFHS2019) (pp. 140–143). Enschede, The Netherlands. bibtex: '@inproceedings{Dunst_Bornmann_Hemsel_Littmann_Sextro_2019, place={Enschede, The Netherlands}, title={Atomization of Fluids with Ultrasound}, booktitle={Conference Proceedings - The 4th Conference on MicroFluidic Handling Systems (MFHS2019)}, author={Dunst, Paul and Bornmann, Peter and Hemsel, Tobias and Littmann, Walter and Sextro, Walter}, editor={Lötters, Joost and Urban, GeraldEditors}, year={2019}, pages={140–143} }' chicago: Dunst, Paul, Peter Bornmann, Tobias Hemsel, Walter Littmann, and Walter Sextro. “Atomization of Fluids with Ultrasound.” In Conference Proceedings - The 4th Conference on MicroFluidic Handling Systems (MFHS2019), edited by Joost Lötters and Gerald Urban, 140–43. Enschede, The Netherlands, 2019. ieee: P. Dunst, P. Bornmann, T. Hemsel, W. Littmann, and W. Sextro, “Atomization of Fluids with Ultrasound,” in Conference Proceedings - The 4th Conference on MicroFluidic Handling Systems (MFHS2019), Enschede, The Netherlands, 2019, pp. 140–143. mla: Dunst, Paul, et al. “Atomization of Fluids with Ultrasound.” Conference Proceedings - The 4th Conference on MicroFluidic Handling Systems (MFHS2019), edited by Joost Lötters and Gerald Urban, 2019, pp. 140–43. short: 'P. Dunst, P. Bornmann, T. Hemsel, W. Littmann, W. Sextro, in: J. Lötters, G. Urban (Eds.), Conference Proceedings - The 4th Conference on MicroFluidic Handling Systems (MFHS2019), Enschede, The Netherlands, 2019, pp. 140–143.' conference: end_date: 2019-10-04 location: Enschede, The Netherlands name: 4th Conference on MicroFluidic Handling Systems start_date: 2019-10-02 date_created: 2019-11-07T15:25:30Z date_updated: 2022-01-06T06:52:08Z ddc: - '620' department: - _id: '151' editor: - first_name: Joost full_name: Lötters, Joost last_name: Lötters - first_name: Gerald full_name: Urban, Gerald last_name: Urban file: - access_level: closed content_type: application/pdf creator: pdunst date_created: 2019-11-07T15:22:56Z date_updated: 2019-11-07T15:22:56Z file_id: '14853' file_name: Dunst_MFHS_2019.pdf file_size: 3850591 relation: main_file success: 1 file_date_updated: 2019-11-07T15:22:56Z has_accepted_license: '1' keyword: - atomization - ultrasound - standing-wave - capillarywave - vibrating-mesh language: - iso: eng page: 140-143 place: Enschede, The Netherlands publication: Conference Proceedings - The 4th Conference on MicroFluidic Handling Systems (MFHS2019) publication_status: published quality_controlled: '1' status: public title: Atomization of Fluids with Ultrasound type: conference user_id: '22130' year: '2019' ... --- _id: '10258' abstract: - lang: eng text: Für die Zerstäubung hochviskoser Flüssigkeiten werden neben Düsenzerstäubern vor allem UltraschallStehwellenzerstäuber angewendet [1]. Diese ermöglichen ohne weitere Maßnahmen zwar keine gerichtete Zerstäubung, benötigen jedoch im Gegensatz zu Düsenzerstäubern keine hohen Drücke und haben keine hohen Austrittsgeschwindigkeiten. Zur Erzeugung der Ultraschallwellen werden typischerweise piezoelektrische, mit Bolzen verschraubte LangevinWandler verwendet [1-4], die eine starke Schallabstrahlung bei einer elektrischen Eingangsleistung von bis zu einigen Kilowatt erzeugen können. Wie bei jedem anderen schwingenden System emittiert der Ultraschallwandler zunächst eine Wanderwelle. Mit einem Reflektor, der gegenüber der Sonotrode angeordnet ist, wird eine stehende Welle erzeugt. Im Resonanzabstand zwischen Reflektor und Wandler werden abgestrahlte und reflektierte Wellen so überlagert, dass höhere Schalldruckamplituden erzielt werden. Ein einfacher Ansatz zur Maximierung des Schallpegels im Stehwellenfeld ist die Erhöhung der Schwingungsamplituden des Wandlers, die jedoch zu Schäden oder zumindest zu einer Verringerung der Lebensdauer führen kann. Hohe Schalldrücke werden auch bei geringen Abständen zwischen Wandler und Reflektor erreicht. Das Volumen des Schallfeldes ist in diesem Fall jedoch für die meisten Prozesse zu klein. Ein weiterer Ansatz ist die Verwendung zweier entgegengesetzt angeordneter Wandler [5]. In diesem Fall erfordert jedoch die Erzeugung einer stehenden Welle eine genaue Abstimmung von Frequenz und Phase beider Wandler, was eine komplexe Steuerung erfordert. Ebenso ist es möglich, geometrische Randbedingungen des Stehwellensystems zu optimieren, sodass es zu optimaler Interferenz der Wellen kommt. Im Folgenden wird der Anschaulichkeit halber vereinfachend angenommen, dass der Wandler an seiner Sonotrodenoberfläche einzelne Schallstrahlen aussendet, die in Nähe des Wandlers nahezu parallel verlaufen und sich mit zunehmender Entfernung vom Wandler auffächern. Ein einfaches Stehwellensystem, bestehend aus ebener Sonotrode und ebenem Reflektor, erzeugt bei kleinem Abstand zwischen Sonotrode und Reflektor sehr hohe Schallpegel, da nahezu sämtliche ausgesandten Schallstrahlen in Richtung der Sonotrode reflektiert werden positive Interferenz entsteht. Erhöht man jedoch den Abstand zwischen Sonotrode und Reflektor, so nehmen die Verluste durch Schallstrahlen, die den Prozessraum verlassen, zu. Wie Abbildung 1 gezeigt, werden nur Schallstrahlen, die in etwa parallel zur Rotationsachse verlaufen, zum Wandler zurück reflektiert und tragen zum Stehwellenfeld bei. Die Strahlen haben zudem abhängig vom Abstrahlwinkel unterschiedliche Weglängen. Die Stehwellenbedingung ist demnach nur für Strahlen in der Nähe der Rotationsachse exakt erfüllt. Um dies zu vermeiden, müssen die Geometrien von Wandler und Reflektor optimiert werden. In den folgenden Abschnitten wird zunächst ein Optimierungsansatz vorgestellt. Mithilfe eines FiniteElemente-Modells werden die Auswirkungen einer optimierten Geometrie auf den maximalen Schalldruckpegel untersucht. Ergebnisse werden durch Messungen an einem experimentellen Aufbau eines Stehwellensystems validiert. Es wird gezeigt, wie sich die Optimierung der geometrischen Randbedingungen auf die Zerstäubung hochviskoser Flüssigkeiten auswirkt. author: - first_name: Paul full_name: Dunst, Paul id: '22130' last_name: Dunst - first_name: Tobias full_name: Hemsel, Tobias id: '210' last_name: Hemsel - first_name: Peter full_name: Bornmann, Peter last_name: Bornmann - first_name: 'Walter ' full_name: 'Littmann, Walter ' last_name: Littmann - first_name: Walter full_name: Sextro, Walter id: '21220' last_name: Sextro citation: ama: 'Dunst P, Hemsel T, Bornmann P, Littmann W, Sextro W. Modellbasierte und experimentelle Charakterisierung von intensiven Ultraschall-Stehwellenfeldern für die Zerstäubung hochviskoser Flüssigkeiten. In: DAGA 2019. ; 2019.' apa: Dunst, P., Hemsel, T., Bornmann, P., Littmann, W., & Sextro, W. (2019). Modellbasierte und experimentelle Charakterisierung von intensiven Ultraschall-Stehwellenfeldern für die Zerstäubung hochviskoser Flüssigkeiten. In DAGA 2019. Rostock. bibtex: '@inproceedings{Dunst_Hemsel_Bornmann_Littmann_Sextro_2019, title={Modellbasierte und experimentelle Charakterisierung von intensiven Ultraschall-Stehwellenfeldern für die Zerstäubung hochviskoser Flüssigkeiten}, booktitle={DAGA 2019}, author={Dunst, Paul and Hemsel, Tobias and Bornmann, Peter and Littmann, Walter and Sextro, Walter}, year={2019} }' chicago: Dunst, Paul, Tobias Hemsel, Peter Bornmann, Walter Littmann, and Walter Sextro. “Modellbasierte Und Experimentelle Charakterisierung von Intensiven Ultraschall-Stehwellenfeldern Für Die Zerstäubung Hochviskoser Flüssigkeiten.” In DAGA 2019, 2019. ieee: P. Dunst, T. Hemsel, P. Bornmann, W. Littmann, and W. Sextro, “Modellbasierte und experimentelle Charakterisierung von intensiven Ultraschall-Stehwellenfeldern für die Zerstäubung hochviskoser Flüssigkeiten,” in DAGA 2019, Rostock, 2019. mla: Dunst, Paul, et al. “Modellbasierte Und Experimentelle Charakterisierung von Intensiven Ultraschall-Stehwellenfeldern Für Die Zerstäubung Hochviskoser Flüssigkeiten.” DAGA 2019, 2019. short: 'P. Dunst, T. Hemsel, P. Bornmann, W. Littmann, W. Sextro, in: DAGA 2019, 2019.' conference: end_date: 2019-03-21 location: Rostock name: Deutsche Jahrestagung für Akustik - DAGA 2019 start_date: 2019-03-18 date_created: 2019-06-17T13:01:47Z date_updated: 2022-01-06T06:50:33Z department: - _id: '151' language: - iso: eng publication: DAGA 2019 status: public title: Modellbasierte und experimentelle Charakterisierung von intensiven Ultraschall-Stehwellenfeldern für die Zerstäubung hochviskoser Flüssigkeiten type: conference user_id: '22130' year: '2019' ... --- _id: '10000' abstract: - lang: eng text: Ultraschall wird zur Effizienzsteigerung in verfahrenstechnischen Prozessen eingesetzt. Die Betriebsparamter der Ultraschallsysteme werden empirisch ermittelt, da derzeit keine systematische Analyse der Wechselwirkung zwischen Ultraschallwandler und Schallfeld sowie kein Verfahren zur Messung der Kavitationsaktivität ohne zusätzlichen Sensor existieren. Auf Basis einer experimentellen Analyse des betrachteten sonochemischen Reaktors wird ein Finite-Elemente-Modell aufgebaut, das die Wechselwirkung zwischen Schallfeld und Ultraschallwandler berücksichtigt. Die modellbasierte Analyse zeigt, dass wegen der akustischen Eigenschaften des Autoklavs nur direkt an der Sonotrode Kavitation entsteht. Die Wechselwirkung zwischen Ultraschallwandler und Schallfeld ermöglicht Aussagen über das Schallfeld und die Kavitationsaktivität auf Basis der Rückwirkung auf den Ultraschallwandler. Die lineare Schalldruckverteilung ermöglicht eine Prognose über die Verteilung von Kavitationszonen. Das beschriebene Modell liefert wertvolle Erkenntnisse für die Auslegung, Analyse und Skalierung sonochemischer Reaktoren. Auf Grund der rauen Prozessrandbedingungen ist die Applikation von Sensoren zur Überwachung der Kavitationsaktivität in vielen sonochemischen Prozessen nicht möglich. Zur prozessbegleitenden Messung der Kavitationsaktivität wird ein Verfahren entwickelt, das die Bewertung der Kavitationsaktivität durch Auswertung der Rückwirkung auf den Ultraschallwandler erlaubt. Das Messverfahren ermöglicht eine vorhersagbare und reproduzierbare Durchführung kavitationsbasierter Prozesse und stellt eine wichtige Erweiterung für bestehende und neue Ultraschallsysteme dar. author: - first_name: Peter full_name: Bornmann, Peter last_name: Bornmann citation: ama: Bornmann P. Modellierung Und Experimentelle Charakterisierung Der Wechselwirkung Zwischen Ultraschallwandler Und Flüssigkeit in Kavitationsbasierten Prozessen. Shaker; 2019. apa: Bornmann, P. (2019). Modellierung und experimentelle Charakterisierung der Wechselwirkung zwischen Ultraschallwandler und Flüssigkeit in kavitationsbasierten Prozessen. Shaker. bibtex: '@book{Bornmann_2019, title={Modellierung und experimentelle Charakterisierung der Wechselwirkung zwischen Ultraschallwandler und Flüssigkeit in kavitationsbasierten Prozessen}, publisher={Shaker}, author={Bornmann, Peter}, year={2019} }' chicago: Bornmann, Peter. Modellierung Und Experimentelle Charakterisierung Der Wechselwirkung Zwischen Ultraschallwandler Und Flüssigkeit in Kavitationsbasierten Prozessen. Shaker, 2019. ieee: P. Bornmann, Modellierung und experimentelle Charakterisierung der Wechselwirkung zwischen Ultraschallwandler und Flüssigkeit in kavitationsbasierten Prozessen. Shaker, 2019. mla: Bornmann, Peter. Modellierung Und Experimentelle Charakterisierung Der Wechselwirkung Zwischen Ultraschallwandler Und Flüssigkeit in Kavitationsbasierten Prozessen. Shaker, 2019. short: P. Bornmann, Modellierung Und Experimentelle Charakterisierung Der Wechselwirkung Zwischen Ultraschallwandler Und Flüssigkeit in Kavitationsbasierten Prozessen, Shaker, 2019. date_created: 2019-05-27T10:29:53Z date_updated: 2023-09-15T12:23:55Z department: - _id: '151' keyword: - Sonochemie - Akustische Kavitation - Kavitationsmessung - Kavitationsdetektion - FEM-Simulation Ultraschallwandler - Prozessüberwachung - FEM-Simulation Schallfeld - Self-Sensing - Piezoelektrische Ultraschallwandler - Ultraschallreinigung language: - iso: eng publisher: Shaker status: public title: Modellierung und experimentelle Charakterisierung der Wechselwirkung zwischen Ultraschallwandler und Flüssigkeit in kavitationsbasierten Prozessen type: dissertation user_id: '210' year: '2019' ... --- _id: '9990' abstract: - lang: eng text: The handling of fine powders is an important task in modern production processes. However, as fine powders strongly tend to adhesion and agglomeration, their processing with conventional methods is difficult or impossible. Especially when processing small amounts of highly sensitive fine powders, conventional methods reach their technical limits. In process steps such as dosing, transport, and especially mixing of fine powders new methods are required. Apart from the well-known method of manipulating powder properties by adding chemical additives, this contribution aims at improving the handling of dry fine powders by using vibrations at different frequencies. Modules are presented, which enable the continuous dosing, the homogeneous mixing and the transport of dry fine powders. Finally, these modules are combined for the production of a homogeneous mixture of two dry fine powders. author: - first_name: Paul full_name: Dunst, Paul id: '22130' last_name: Dunst - first_name: Peter full_name: Bornmann, Peter last_name: Bornmann - first_name: Tobias full_name: Hemsel, Tobias id: '210' last_name: Hemsel - first_name: Walter. full_name: Littmann, Walter. last_name: Littmann - first_name: Walter full_name: Sextro, Walter id: '21220' last_name: Sextro citation: ama: Dunst P, Bornmann P, Hemsel T, Littmann W, Sextro W. Vibration Assisted Dosing, Mixing and Transport of Dry Fine Powders. ACTUATOR 2018; 16th International Conference on New Actuators. 2018:142-145. apa: Dunst, P., Bornmann, P., Hemsel, T., Littmann, W., & Sextro, W. (2018). Vibration Assisted Dosing, Mixing and Transport of Dry Fine Powders. ACTUATOR 2018; 16th International Conference on New Actuators, 142–145. bibtex: '@article{Dunst_Bornmann_Hemsel_Littmann_Sextro_2018, title={Vibration Assisted Dosing, Mixing and Transport of Dry Fine Powders}, journal={ACTUATOR 2018; 16th International Conference on New Actuators}, author={Dunst, Paul and Bornmann, Peter and Hemsel, Tobias and Littmann, Walter. and Sextro, Walter}, year={2018}, pages={142–145} }' chicago: Dunst, Paul, Peter Bornmann, Tobias Hemsel, Walter. Littmann, and Walter Sextro. “Vibration Assisted Dosing, Mixing and Transport of Dry Fine Powders.” ACTUATOR 2018; 16th International Conference on New Actuators, 2018, 142–45. ieee: P. Dunst, P. Bornmann, T. Hemsel, W. Littmann, and W. Sextro, “Vibration Assisted Dosing, Mixing and Transport of Dry Fine Powders,” ACTUATOR 2018; 16th International Conference on New Actuators, pp. 142–145, 2018. mla: Dunst, Paul, et al. “Vibration Assisted Dosing, Mixing and Transport of Dry Fine Powders.” ACTUATOR 2018; 16th International Conference on New Actuators, 2018, pp. 142–45. short: P. Dunst, P. Bornmann, T. Hemsel, W. Littmann, W. Sextro, ACTUATOR 2018; 16th International Conference on New Actuators (2018) 142–145. date_created: 2019-05-27T10:13:10Z date_updated: 2019-09-16T09:45:13Z department: - _id: '151' language: - iso: eng page: 142-145 publication: ACTUATOR 2018; 16th International Conference on New Actuators quality_controlled: '1' status: public title: Vibration Assisted Dosing, Mixing and Transport of Dry Fine Powders type: journal_article user_id: '55222' year: '2018' ... --- _id: '9991' abstract: - lang: eng text: Abstract:Since fine powders tend strongly to adhesion and agglomeration, their processing withconventional methods is difficult or impossible. Typically, in order to enable the handling of finepowders, chemicals are added to increase the flowability and reduce adhesion. This contributionshows that instead of additives also vibrations can be used to increase the flowability, to reduceadhesion and cohesion, and thus to enable or improve processes such as precision dosing, mixing,and transport of very fine powders. The methods for manipulating powder properties are describedin detail and prototypes for experimental studies are presented. It is shown that the handling of finepowders can be improved by using low-frequency, high-frequency or a combination of low- andhigh-frequency vibration. author: - first_name: Paul full_name: Dunst, Paul id: '22130' last_name: Dunst - first_name: Peter full_name: Bornmann, Peter last_name: Bornmann - first_name: Tobias full_name: Hemsel, Tobias id: '210' last_name: Hemsel - first_name: Walter full_name: Sextro, Walter id: '21220' last_name: Sextro citation: ama: Dunst P, Bornmann P, Hemsel T, Sextro W. Vibration-Assisted Handling of Dry Fine Powders. Actuators 2018, 7(2). 2018:1-11. doi:10.3390/act7020018 apa: Dunst, P., Bornmann, P., Hemsel, T., & Sextro, W. (2018). Vibration-Assisted Handling of Dry Fine Powders. Actuators 2018, 7(2)., 1–11. https://doi.org/10.3390/act7020018 bibtex: '@article{Dunst_Bornmann_Hemsel_Sextro_2018, title={Vibration-Assisted Handling of Dry Fine Powders}, DOI={10.3390/act7020018}, journal={Actuators 2018, 7(2).}, author={Dunst, Paul and Bornmann, Peter and Hemsel, Tobias and Sextro, Walter}, year={2018}, pages={1–11} }' chicago: Dunst, Paul, Peter Bornmann, Tobias Hemsel, and Walter Sextro. “Vibration-Assisted Handling of Dry Fine Powders.” Actuators 2018, 7(2)., 2018, 1–11. https://doi.org/10.3390/act7020018. ieee: P. Dunst, P. Bornmann, T. Hemsel, and W. Sextro, “Vibration-Assisted Handling of Dry Fine Powders,” Actuators 2018, 7(2)., pp. 1–11, 2018. mla: Dunst, Paul, et al. “Vibration-Assisted Handling of Dry Fine Powders.” Actuators 2018, 7(2)., 2018, pp. 1–11, doi:10.3390/act7020018. short: P. Dunst, P. Bornmann, T. Hemsel, W. Sextro, Actuators 2018, 7(2). (2018) 1–11. date_created: 2019-05-27T10:16:16Z date_updated: 2019-09-16T09:44:54Z department: - _id: '151' doi: 10.3390/act7020018 keyword: - powder handling - flowability - dosing - transport - mixing - dispersion - piezoelectricactuators - vibrations language: - iso: eng page: 1-11 publication: Actuators 2018, 7(2). quality_controlled: '1' status: public title: Vibration-Assisted Handling of Dry Fine Powders type: journal_article user_id: '55222' year: '2018' ... --- _id: '9958' abstract: - lang: eng text: The transportation of dry fine powders is an emerging technologic task, as in biotechnology, pharmaceutical or coatings industry particle sizes of processed powders are getting smaller and smaller. Fine powders are primarily defined by the fact that adhesive and cohesive forces outweigh the weight forces. This leads to mostly unwanted agglomeration (clumping) and adhesion to surfaces, what makes it more difficult to use conventional conveyor systems (e. g. pneumatic or vibratory conveyors) for transport. A rather new method for transporting these fine powders is based on ultrasonic vibrations, which are used to reduce friction and adhesion between powder and the substrate. One very effective set-up consists of a pipe, which vibrates harmoniously in axial direction at low frequency combined with a pulsed radial high frequency vibration. The high frequency vibration accelerates the particles perpendicular to the surface of the pipe, which in average leads to lower normal and thereby smaller friction force. With coordinated friction manipulation the powder acceleration can be varied so that the powder may be greatly accelerated and only slightly decelerated in each excitation period of the low frequency axial vibration of the pipe. The amount of powder flow is adjustable by vibration amplitudes, frequencies, and pulse rate, which makes the device versatile for comparable high volume and fine dosing using one setup. Within this contribution an experimental set-up consisting of a pipe, a solenoid actuator for axial vibration and a piezoelectric actuator for the radial high frequency vibration is described. An analytical model is shown, that simulates the powder velocity. Finally, simulation results are validated by experimental data for different driving parameters such as amplitude of low frequency vibration, pipe material and inclination angle. author: - first_name: Paul full_name: Dunst, Paul id: '22130' last_name: Dunst - first_name: Walter full_name: Sextro, Walter id: '21220' last_name: Sextro - first_name: Peter full_name: Bornmann, Peter last_name: Bornmann - first_name: Tobias full_name: Hemsel, Tobias id: '210' last_name: Hemsel - first_name: Walter full_name: Littmann, Walter last_name: Littmann citation: ama: 'Dunst P, Sextro W, Bornmann P, Hemsel T, Littmann W. Transportation of dry fine powders by coordinated friction manipulation. In: PAMM Proc. Appl. Math. Mech. 16. Braunschweig; 2016:635-636. doi:10.1002/pamm.201610306' apa: Dunst, P., Sextro, W., Bornmann, P., Hemsel, T., & Littmann, W. (2016). Transportation of dry fine powders by coordinated friction manipulation. In PAMM Proc. Appl. Math. Mech. 16 (pp. 635–636). Braunschweig. https://doi.org/10.1002/pamm.201610306 bibtex: '@inproceedings{Dunst_Sextro_Bornmann_Hemsel_Littmann_2016, place={Braunschweig}, title={Transportation of dry fine powders by coordinated friction manipulation}, DOI={10.1002/pamm.201610306}, booktitle={PAMM Proc. Appl. Math. Mech. 16}, author={Dunst, Paul and Sextro, Walter and Bornmann, Peter and Hemsel, Tobias and Littmann, Walter}, year={2016}, pages={635–636} }' chicago: Dunst, Paul, Walter Sextro, Peter Bornmann, Tobias Hemsel, and Walter Littmann. “Transportation of Dry Fine Powders by Coordinated Friction Manipulation.” In PAMM Proc. Appl. Math. Mech. 16, 635–36. Braunschweig, 2016. https://doi.org/10.1002/pamm.201610306. ieee: P. Dunst, W. Sextro, P. Bornmann, T. Hemsel, and W. Littmann, “Transportation of dry fine powders by coordinated friction manipulation,” in PAMM Proc. Appl. Math. Mech. 16, 2016, pp. 635–636. mla: Dunst, Paul, et al. “Transportation of Dry Fine Powders by Coordinated Friction Manipulation.” PAMM Proc. Appl. Math. Mech. 16, 2016, pp. 635–36, doi:10.1002/pamm.201610306. short: 'P. Dunst, W. Sextro, P. Bornmann, T. Hemsel, W. Littmann, in: PAMM Proc. Appl. Math. Mech. 16, Braunschweig, 2016, pp. 635–636.' date_created: 2019-05-27T08:57:25Z date_updated: 2019-05-27T08:59:25Z department: - _id: '151' doi: 10.1002/pamm.201610306 language: - iso: eng page: 635-636 place: Braunschweig publication: PAMM Proc. Appl. Math. Mech. 16 status: public title: Transportation of dry fine powders by coordinated friction manipulation type: conference user_id: '55222' year: '2016' ... --- _id: '9944' abstract: - lang: eng text: Eine Vielzahl von Prozessen in der Chemie und Verfahrenstechnik kann durch Ultraschall positiv beeinflusst werden. Oftmals ist ultraschallinduzierte Kavitation der Hauptwirkmechanismus für die positiven Effekte der Beschallung. Daher ist es notwendig die Kavitationsaktivität während des Prozesses zu quantifizieren um die Beschallung für den jeweiligen Prozess optimal gestalten und überwachen zu können. Eine Möglichkeit der prozessbegleitenden Kavitationsdetektion ist die Auswertung der akustischen Emissionen von oszillierenden und kollabierenden Kavitationsblasen mittels Drucksensoren in der Flüssigkeit. Raue Prozessrandbedingungen wie hohe Temperaturen oder aggressive Flüssigkeiten erschweren es jedoch geeignete Sensoren zu finden. Als Alternative wurde daher die Nutzbarkeit der Rückwirkung von Kavitationsereignissen auf das elektrische Eingansgssignal des Ultraschallwandlers zur Quantifizierung von Kavitation untersucht. Die experimentelle Analyse hat ergeben, dass das Einsetzen und in einigen Fällen auch die Art der Kavitation auf Basis der Rückwirkung auf das Stromsignal des Ultraschallwandlers bestimmt werden kann. Die Stärke der Kavitation war hingegen nicht aus den Stromsignalen abzuleiten. author: - first_name: Peter full_name: Bornmann, Peter last_name: Bornmann - first_name: Tobias full_name: Hemsel, Tobias id: '210' last_name: Hemsel - first_name: Walter full_name: Sextro, Walter id: '21220' last_name: Sextro - first_name: Gianluca full_name: Memoli, Gianluca last_name: Memoli - first_name: Mark full_name: Hodnett, Mark last_name: Hodnett - first_name: Bajram full_name: Zeqiri, Bajram last_name: Zeqiri citation: ama: Bornmann P, Hemsel T, Sextro W, Memoli G, Hodnett M, Zeqiri B. Kavitationsdetektion mittels Self-Sensing-Ultraschallwandler. tm - Technisches Messen. 2015;82(2):73-84. doi:10.1515/teme-2015-0017 apa: Bornmann, P., Hemsel, T., Sextro, W., Memoli, G., Hodnett, M., & Zeqiri, B. (2015). Kavitationsdetektion mittels Self-Sensing-Ultraschallwandler. Tm - Technisches Messen, 82(2), 73–84. https://doi.org/10.1515/teme-2015-0017 bibtex: '@article{Bornmann_Hemsel_Sextro_Memoli_Hodnett_Zeqiri_2015, title={Kavitationsdetektion mittels Self-Sensing-Ultraschallwandler}, volume={82}, DOI={10.1515/teme-2015-0017}, number={2}, journal={tm - Technisches Messen}, author={Bornmann, Peter and Hemsel, Tobias and Sextro, Walter and Memoli, Gianluca and Hodnett, Mark and Zeqiri, Bajram}, year={2015}, pages={73–84} }' chicago: 'Bornmann, Peter, Tobias Hemsel, Walter Sextro, Gianluca Memoli, Mark Hodnett, and Bajram Zeqiri. “Kavitationsdetektion Mittels Self-Sensing-Ultraschallwandler.” Tm - Technisches Messen 82, no. 2 (2015): 73–84. https://doi.org/10.1515/teme-2015-0017.' ieee: P. Bornmann, T. Hemsel, W. Sextro, G. Memoli, M. Hodnett, and B. Zeqiri, “Kavitationsdetektion mittels Self-Sensing-Ultraschallwandler,” tm - Technisches Messen, vol. 82, no. 2, pp. 73–84, 2015. mla: Bornmann, Peter, et al. “Kavitationsdetektion Mittels Self-Sensing-Ultraschallwandler.” Tm - Technisches Messen, vol. 82, no. 2, 2015, pp. 73–84, doi:10.1515/teme-2015-0017. short: P. Bornmann, T. Hemsel, W. Sextro, G. Memoli, M. Hodnett, B. Zeqiri, Tm - Technisches Messen 82 (2015) 73–84. date_created: 2019-05-27T08:13:40Z date_updated: 2019-09-16T10:44:38Z department: - _id: '151' doi: 10.1515/teme-2015-0017 intvolume: ' 82' issue: '2' keyword: - Kavitationsdetektion - Self-Sensing - So- nochemie - Ultraschallwandler language: - iso: eng page: 73-84 popular_science: '1' publication: tm - Technisches Messen status: public title: Kavitationsdetektion mittels Self-Sensing-Ultraschallwandler type: journal_article user_id: '55222' volume: 82 year: '2015' ... --- _id: '9948' author: - first_name: Ryo full_name: Kudo, Ryo last_name: Kudo - first_name: Peter full_name: Bornmann, Peter last_name: Bornmann - first_name: Tobias full_name: Hemsel, Tobias id: '210' last_name: Hemsel - first_name: Takeshi full_name: Morita, Takeshi last_name: Morita citation: ama: Kudo R, Bornmann P, Hemsel T, Morita T. Thick KNbO 3 films deposited by ultrasonic-assisted hydrothermal method. Acoustical Science and Technology. 2015;36(3):262-264. doi:10.1250/ast.36.262 apa: Kudo, R., Bornmann, P., Hemsel, T., & Morita, T. (2015). Thick KNbO 3 films deposited by ultrasonic-assisted hydrothermal method. Acoustical Science and Technology, 36(3), 262–264. https://doi.org/10.1250/ast.36.262 bibtex: '@article{Kudo_Bornmann_Hemsel_Morita_2015, title={Thick KNbO 3 films deposited by ultrasonic-assisted hydrothermal method}, volume={36}, DOI={10.1250/ast.36.262}, number={3}, journal={Acoustical Science and Technology}, publisher={Acoustical Society of Japan}, author={Kudo, Ryo and Bornmann, Peter and Hemsel, Tobias and Morita, Takeshi}, year={2015}, pages={262–264} }' chicago: 'Kudo, Ryo, Peter Bornmann, Tobias Hemsel, and Takeshi Morita. “Thick KNbO 3 Films Deposited by Ultrasonic-Assisted Hydrothermal Method.” Acoustical Science and Technology 36, no. 3 (2015): 262–64. https://doi.org/10.1250/ast.36.262.' ieee: R. Kudo, P. Bornmann, T. Hemsel, and T. Morita, “Thick KNbO 3 films deposited by ultrasonic-assisted hydrothermal method,” Acoustical Science and Technology, vol. 36, no. 3, pp. 262–264, 2015. mla: Kudo, Ryo, et al. “Thick KNbO 3 Films Deposited by Ultrasonic-Assisted Hydrothermal Method.” Acoustical Science and Technology, vol. 36, no. 3, Acoustical Society of Japan, 2015, pp. 262–64, doi:10.1250/ast.36.262. short: R. Kudo, P. Bornmann, T. Hemsel, T. Morita, Acoustical Science and Technology 36 (2015) 262–264. date_created: 2019-05-27T08:28:31Z date_updated: 2019-09-16T10:51:23Z department: - _id: '151' doi: 10.1250/ast.36.262 intvolume: ' 36' issue: '3' language: - iso: eng page: 262-264 publication: Acoustical Science and Technology publisher: Acoustical Society of Japan quality_controlled: '1' status: public title: Thick KNbO 3 films deposited by ultrasonic-assisted hydrothermal method type: journal_article user_id: '55222' volume: 36 year: '2015' ... --- _id: '9869' abstract: - lang: eng text: Cavitation monitoring is desired to optimize the sonication for diverse sonochemical processes and to detect changes or malfunctions during operation. In situ cavitation measurements can be carried out by detection of the acoustic emissions of cavitation bubbles by sensors in the liquid. However, in harsh environments sensors might not be applicable. Thus, the impact of cavitation on the electrical signals of a piezoelectric transducer has been analyzed as alternative method to measure the threshold, strength and type of cavitation. The applicability has been tested in three different setups to evaluate the general- izability of extracted indicators. In all setups indicators for the cavitation thresholds could be derived from the current signal. In two setups features showed two thresholds that may be linked to the types of cavitation. However, only one feature derived from the current signal in one particular setup correlated to the strength of cavitation. Cavitation detection based on the current signal of the transducer is a useful method to detect cavitation in harsh environments and without perturbing the sound field. Once appli- cable indicators have been identified, they may easily be tracked during the process. However, for more detailed studies about the cavitation activity and its spatial distribution, measurements with in situ sensors are recommended. author: - first_name: Peter full_name: Bornmann, Peter last_name: Bornmann - first_name: Tobias full_name: Hemsel, Tobias id: '210' last_name: Hemsel - first_name: Walter full_name: Sextro, Walter id: '21220' last_name: Sextro - first_name: Gianluca full_name: Memoli, Gianluca last_name: Memoli - first_name: Mark full_name: Hodnett, Mark last_name: Hodnett - first_name: Bajram full_name: Zeqiri, Bajram last_name: Zeqiri citation: ama: 'Bornmann P, Hemsel T, Sextro W, Memoli G, Hodnett M, Zeqiri B. Self-Sensing Ultrasound Transducer for Cavitation Detection. In: 2014 IEEE International Ultrasonics Symposium Proceedings. ; 2014:663-666. doi:10.1109/ULTSYM.2014.0163' apa: Bornmann, P., Hemsel, T., Sextro, W., Memoli, G., Hodnett, M., & Zeqiri, B. (2014). Self-Sensing Ultrasound Transducer for Cavitation Detection. In 2014 IEEE International Ultrasonics Symposium Proceedings (pp. 663–666). https://doi.org/10.1109/ULTSYM.2014.0163 bibtex: '@inproceedings{Bornmann_Hemsel_Sextro_Memoli_Hodnett_Zeqiri_2014, title={Self-Sensing Ultrasound Transducer for Cavitation Detection}, DOI={10.1109/ULTSYM.2014.0163}, booktitle={2014 IEEE International Ultrasonics Symposium Proceedings}, author={Bornmann, Peter and Hemsel, Tobias and Sextro, Walter and Memoli, Gianluca and Hodnett, Mark and Zeqiri, Bajram}, year={2014}, pages={663–666} }' chicago: Bornmann, Peter, Tobias Hemsel, Walter Sextro, Gianluca Memoli, Mark Hodnett, and Bajram Zeqiri. “Self-Sensing Ultrasound Transducer for Cavitation Detection.” In 2014 IEEE International Ultrasonics Symposium Proceedings, 663–66, 2014. https://doi.org/10.1109/ULTSYM.2014.0163. ieee: P. Bornmann, T. Hemsel, W. Sextro, G. Memoli, M. Hodnett, and B. Zeqiri, “Self-Sensing Ultrasound Transducer for Cavitation Detection,” in 2014 IEEE International Ultrasonics Symposium Proceedings, 2014, pp. 663–666. mla: Bornmann, Peter, et al. “Self-Sensing Ultrasound Transducer for Cavitation Detection.” 2014 IEEE International Ultrasonics Symposium Proceedings, 2014, pp. 663–66, doi:10.1109/ULTSYM.2014.0163. short: 'P. Bornmann, T. Hemsel, W. Sextro, G. Memoli, M. Hodnett, B. Zeqiri, in: 2014 IEEE International Ultrasonics Symposium Proceedings, 2014, pp. 663–666.' date_created: 2019-05-20T12:13:02Z date_updated: 2019-05-20T12:13:41Z department: - _id: '151' doi: 10.1109/ULTSYM.2014.0163 language: - iso: eng page: 663-666 publication: 2014 IEEE International Ultrasonics Symposium Proceedings publication_identifier: isbn: - '9781479970490' status: public title: Self-Sensing Ultrasound Transducer for Cavitation Detection type: conference user_id: '55222' year: '2014' ... --- _id: '9874' author: - first_name: Tobias full_name: Hemsel, Tobias id: '210' last_name: Hemsel - first_name: Peter full_name: Bornmann, Peter last_name: Bornmann - first_name: Takeshi full_name: Morita, Takeshi last_name: Morita - first_name: Christoph full_name: Sondermann-Wölke, Christoph last_name: Sondermann-Wölke - first_name: Walter full_name: Sextro, Walter id: '21220' last_name: Sextro citation: ama: Hemsel T, Bornmann P, Morita T, Sondermann-Wölke C, Sextro W. Reliability analysis of ultrasonic power transducers. Archive of Applied Mechanics. 2014:1-7. doi:10.1007/s00419-014-0965-4 apa: Hemsel, T., Bornmann, P., Morita, T., Sondermann-Wölke, C., & Sextro, W. (2014). Reliability analysis of ultrasonic power transducers. Archive of Applied Mechanics, 1–7. https://doi.org/10.1007/s00419-014-0965-4 bibtex: '@article{Hemsel_Bornmann_Morita_Sondermann-Wölke_Sextro_2014, title={Reliability analysis of ultrasonic power transducers}, DOI={10.1007/s00419-014-0965-4}, journal={Archive of Applied Mechanics}, publisher={Springer Berlin Heidelberg}, author={Hemsel, Tobias and Bornmann, Peter and Morita, Takeshi and Sondermann-Wölke, Christoph and Sextro, Walter}, year={2014}, pages={1–7} }' chicago: Hemsel, Tobias, Peter Bornmann, Takeshi Morita, Christoph Sondermann-Wölke, and Walter Sextro. “Reliability Analysis of Ultrasonic Power Transducers.” Archive of Applied Mechanics, 2014, 1–7. https://doi.org/10.1007/s00419-014-0965-4. ieee: T. Hemsel, P. Bornmann, T. Morita, C. Sondermann-Wölke, and W. Sextro, “Reliability analysis of ultrasonic power transducers,” Archive of Applied Mechanics, pp. 1–7, 2014. mla: Hemsel, Tobias, et al. “Reliability Analysis of Ultrasonic Power Transducers.” Archive of Applied Mechanics, Springer Berlin Heidelberg, 2014, pp. 1–7, doi:10.1007/s00419-014-0965-4. short: T. Hemsel, P. Bornmann, T. Morita, C. Sondermann-Wölke, W. Sextro, Archive of Applied Mechanics (2014) 1–7. date_created: 2019-05-20T13:01:25Z date_updated: 2019-09-16T10:57:23Z department: - _id: '151' doi: 10.1007/s00419-014-0965-4 keyword: - Reliability - Ultrasonic power transducers - FMEA language: - iso: eng page: 1-7 publication: Archive of Applied Mechanics publication_identifier: issn: - 0939-1533 publisher: Springer Berlin Heidelberg quality_controlled: '1' status: public title: Reliability analysis of ultrasonic power transducers type: journal_article user_id: '55222' year: '2014' ... --- _id: '9878' abstract: - lang: eng text: (K,Na)NbO3 ceramics have attracted much attention as lead-free piezoelectric materials with high piezoelectric properties. High-quality (K,Na)NbO3 ceramics can be sintered using KNbO3 and NaNbO3 powders synthesized by a hydrothermal method. In this study, to enhance the quality factor of the ceramics, high-power ultrasonic irradiation was employed during the hydrothermal method, which led to a reduction in the particle size of the resultant powders. author: - first_name: G. full_name: Isobe, G. last_name: Isobe - first_name: Takafumi full_name: Maeda, Takafumi last_name: Maeda - first_name: Peter full_name: Bornmann, Peter last_name: Bornmann - first_name: Tobias full_name: Hemsel, Tobias id: '210' last_name: Hemsel - first_name: Takeshi full_name: Morita, Takeshi last_name: Morita citation: ama: Isobe G, Maeda T, Bornmann P, Hemsel T, Morita T. Synthesis of lead-free piezoelectric powders by ultrasonic-assisted hydrothermal method and properties of sintered (K0.48Na0.52)NBO3 ceramics. Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on. 2014;61(2):225-230. doi:10.1109/TUFFC.2014.6722608 apa: Isobe, G., Maeda, T., Bornmann, P., Hemsel, T., & Morita, T. (2014). Synthesis of lead-free piezoelectric powders by ultrasonic-assisted hydrothermal method and properties of sintered (K0.48Na0.52)NBO3 ceramics. Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions On, 61(2), 225–230. https://doi.org/10.1109/TUFFC.2014.6722608 bibtex: '@article{Isobe_Maeda_Bornmann_Hemsel_Morita_2014, title={Synthesis of lead-free piezoelectric powders by ultrasonic-assisted hydrothermal method and properties of sintered (K0.48Na0.52)NBO3 ceramics}, volume={61}, DOI={10.1109/TUFFC.2014.6722608}, number={2}, journal={Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on}, author={Isobe, G. and Maeda, Takafumi and Bornmann, Peter and Hemsel, Tobias and Morita, Takeshi}, year={2014}, pages={225–230} }' chicago: 'Isobe, G., Takafumi Maeda, Peter Bornmann, Tobias Hemsel, and Takeshi Morita. “Synthesis of Lead-Free Piezoelectric Powders by Ultrasonic-Assisted Hydrothermal Method and Properties of Sintered (K0.48Na0.52)NBO3 Ceramics.” Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions On 61, no. 2 (2014): 225–30. https://doi.org/10.1109/TUFFC.2014.6722608.' ieee: G. Isobe, T. Maeda, P. Bornmann, T. Hemsel, and T. Morita, “Synthesis of lead-free piezoelectric powders by ultrasonic-assisted hydrothermal method and properties of sintered (K0.48Na0.52)NBO3 ceramics,” Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on, vol. 61, no. 2, pp. 225–230, 2014. mla: Isobe, G., et al. “Synthesis of Lead-Free Piezoelectric Powders by Ultrasonic-Assisted Hydrothermal Method and Properties of Sintered (K0.48Na0.52)NBO3 Ceramics.” Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions On, vol. 61, no. 2, 2014, pp. 225–30, doi:10.1109/TUFFC.2014.6722608. short: G. Isobe, T. Maeda, P. Bornmann, T. Hemsel, T. Morita, Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions On 61 (2014) 225–230. date_created: 2019-05-20T13:10:14Z date_updated: 2019-09-16T10:53:17Z department: - _id: '151' doi: 10.1109/TUFFC.2014.6722608 intvolume: ' 61' issue: '2' keyword: - Q-factor - ceramics - crystal growth from solution - particle size - piezoelectric materials - potassium compounds - powders - sintering - sodium compounds - ultrasonic effects - (K0.48Na0.52)NbO3 - KNbO3 powders - NaNbO3 powders - high-power ultrasonic irradiation - lead-free piezoelectric materials - lead-free piezoelectric powders - particle size reduction - piezoelectric properties - quality factor - sintered (K0.48Na0.52)NbO3 ceramics - sintering - ultrasonic-assisted hydrothermal method - Acoustics - Ceramics - Lead - Piezoelectric materials - Powders - Radiation effects - Transducers language: - iso: eng page: 225-230 publication: Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on publication_identifier: issn: - 0885-3010 quality_controlled: '1' status: public title: Synthesis of lead-free piezoelectric powders by ultrasonic-assisted hydrothermal method and properties of sintered (K0.48Na0.52)NBO3 ceramics type: journal_article user_id: '55222' volume: 61 year: '2014' ... --- _id: '9866' abstract: - lang: eng text: The hydrothermal method utilizes a solution-based chemical reaction to synthesize piezoelectric thin films and powders. This method has a number of advantages, such as low-temperature synthesis, and high purity and high quality of the product. In order to promote hydrothermal reactions, we developed an ultrasonic assisted hydrothermal method and confirmed that it produces dense and thick lead--zirconate--titanate (PZT) films. In the hydrothermal method, a crystal growth process follows the nucleation process. In this study, we verified that ultrasonic irradiation is effective for the nucleation process, and there is an optimum irradiation period to obtain thicker PZT films. With this optimization, a 9.2-$\mu$ m-thick PZT polycrystalline film was obtained in a single deposition process. For this film, ultrasonic irradiation was carried out from the beginning of the reaction for 18 h, followed by a 6 h deposition without ultrasonic irradiation. These results indicate that the ultrasonic irradiation mainly promotes the nucleation process. author: - first_name: Kanako full_name: Ohta, Kanako last_name: Ohta - first_name: Gaku full_name: Isobe, Gaku last_name: Isobe - first_name: Peter full_name: Bornmann, Peter last_name: Bornmann - first_name: Tobias full_name: Hemsel, Tobias id: '210' last_name: Hemsel - first_name: Takeshi full_name: Morita, Takeshi last_name: Morita citation: ama: Ohta K, Isobe G, Bornmann P, Hemsel T, Morita T. Study on optimizing ultrasonic irradiation period for thick polycrystalline PZT film by hydrothermal method. Ultrasonics. 2013;53(4):837-841. doi:10.1016/j.ultras.2012.12.003 apa: Ohta, K., Isobe, G., Bornmann, P., Hemsel, T., & Morita, T. (2013). Study on optimizing ultrasonic irradiation period for thick polycrystalline PZT film by hydrothermal method. Ultrasonics, 53(4), 837–841. https://doi.org/10.1016/j.ultras.2012.12.003 bibtex: '@article{Ohta_Isobe_Bornmann_Hemsel_Morita_2013, title={Study on optimizing ultrasonic irradiation period for thick polycrystalline PZT film by hydrothermal method}, volume={53}, DOI={10.1016/j.ultras.2012.12.003}, number={4}, journal={Ultrasonics}, author={Ohta, Kanako and Isobe, Gaku and Bornmann, Peter and Hemsel, Tobias and Morita, Takeshi}, year={2013}, pages={837–841} }' chicago: 'Ohta, Kanako, Gaku Isobe, Peter Bornmann, Tobias Hemsel, and Takeshi Morita. “Study on Optimizing Ultrasonic Irradiation Period for Thick Polycrystalline PZT Film by Hydrothermal Method.” Ultrasonics 53, no. 4 (2013): 837–41. https://doi.org/10.1016/j.ultras.2012.12.003.' ieee: K. Ohta, G. Isobe, P. Bornmann, T. Hemsel, and T. Morita, “Study on optimizing ultrasonic irradiation period for thick polycrystalline PZT film by hydrothermal method,” Ultrasonics, vol. 53, no. 4, pp. 837–841, 2013. mla: Ohta, Kanako, et al. “Study on Optimizing Ultrasonic Irradiation Period for Thick Polycrystalline PZT Film by Hydrothermal Method.” Ultrasonics, vol. 53, no. 4, 2013, pp. 837–41, doi:10.1016/j.ultras.2012.12.003. short: K. Ohta, G. Isobe, P. Bornmann, T. Hemsel, T. Morita, Ultrasonics 53 (2013) 837–841. date_created: 2019-05-20T12:03:07Z date_updated: 2019-09-16T10:54:27Z department: - _id: '151' doi: 10.1016/j.ultras.2012.12.003 intvolume: ' 53' issue: '4' keyword: - Piezoelectric material language: - iso: eng page: 837 - 841 publication: Ultrasonics publication_identifier: issn: - 0041-624X quality_controlled: '1' status: public title: Study on optimizing ultrasonic irradiation period for thick polycrystalline PZT film by hydrothermal method type: journal_article user_id: '55222' volume: 53 year: '2013' ... --- _id: '9867' abstract: - lang: eng text: We report the piezoelectric properties of CuO-doped hydrothermal (K,Na)NbO3 ceramics that can be applied as hard-type lead-free piezoelectric ceramics. To date, we have succeeded in synthesizing high-quality KNbO3 and NaNbO3 powders by the hydrothermal method, which is based on an ionic reaction at high temperature (around 210 $\,^{\circ}$C) and pressure. Increasing both the piezoelectric constant d and the mechanical quality factor (Qm) is important for resonance-type piezoelectric devices, such as ultrasonic motors and transformers. CuO doping into hydrothermal (K,Na)NbO3 ceramics was examined to realize hard-type lead-free piezoelectric ceramics. By doping with 1.2 mol \% CuO, Qm was increased and the dielectric loss (tan δ) was decreased to 0.5\%. The grain size was also influenced by the amount of CuO doping, which indicates that Qm is related to the density. To achieve a higher Qm value, the grain size is required to be less than 5 µm; however, excessive CuO doping leads to anomalous grain growth. Optimal piezoelectric properties were obtained for 1.2 mol \% CuO-doped (K,Na)NbO3; k31 = 0.32, d31 = -44 pC/N, Qm (radial) = 959, and tan δ= 0.5\%. These characteristics showed that CuO doping with hydrothermal powders is effective for obtaining hard-type ceramics, and the mechanical quality factor is more than ten times higher than that of nondoped hydrothermal (K,Na)NbO3 ceramics. Therefore, compared with the conventional solid-state method, we could succeed in obtaining hard-type ceramics by a simple and short process. author: - first_name: Yuriko full_name: Yokouchi, Yuriko last_name: Yokouchi - first_name: Takafumi full_name: Maeda, Takafumi last_name: Maeda - first_name: Peter full_name: Bornmann, Peter last_name: Bornmann - first_name: Tobias full_name: Hemsel, Tobias id: '210' last_name: Hemsel - first_name: Takeshi full_name: Morita, Takeshi last_name: Morita citation: ama: Yokouchi Y, Maeda T, Bornmann P, Hemsel T, Morita T. Piezoelectric Properties of CuO-Doped (K,Na)NbO3 Lead-Free Ceramics Synthesized with Hydrothermal Powders. Japanese Journal of Applied Physics. 2013;52(7S). doi:10.7567/JJAP.52.07HB03 apa: Yokouchi, Y., Maeda, T., Bornmann, P., Hemsel, T., & Morita, T. (2013). Piezoelectric Properties of CuO-Doped (K,Na)NbO3 Lead-Free Ceramics Synthesized with Hydrothermal Powders. Japanese Journal of Applied Physics, 52(7S). https://doi.org/10.7567/JJAP.52.07HB03 bibtex: '@article{Yokouchi_Maeda_Bornmann_Hemsel_Morita_2013, title={Piezoelectric Properties of CuO-Doped (K,Na)NbO3 Lead-Free Ceramics Synthesized with Hydrothermal Powders}, volume={52}, DOI={10.7567/JJAP.52.07HB03}, number={7S}, journal={Japanese Journal of Applied Physics}, author={Yokouchi, Yuriko and Maeda, Takafumi and Bornmann, Peter and Hemsel, Tobias and Morita, Takeshi}, year={2013} }' chicago: Yokouchi, Yuriko, Takafumi Maeda, Peter Bornmann, Tobias Hemsel, and Takeshi Morita. “Piezoelectric Properties of CuO-Doped (K,Na)NbO3 Lead-Free Ceramics Synthesized with Hydrothermal Powders.” Japanese Journal of Applied Physics 52, no. 7S (2013). https://doi.org/10.7567/JJAP.52.07HB03. ieee: Y. Yokouchi, T. Maeda, P. Bornmann, T. Hemsel, and T. Morita, “Piezoelectric Properties of CuO-Doped (K,Na)NbO3 Lead-Free Ceramics Synthesized with Hydrothermal Powders,” Japanese Journal of Applied Physics, vol. 52, no. 7S, 2013. mla: Yokouchi, Yuriko, et al. “Piezoelectric Properties of CuO-Doped (K,Na)NbO3 Lead-Free Ceramics Synthesized with Hydrothermal Powders.” Japanese Journal of Applied Physics, vol. 52, no. 7S, 2013, doi:10.7567/JJAP.52.07HB03. short: Y. Yokouchi, T. Maeda, P. Bornmann, T. Hemsel, T. Morita, Japanese Journal of Applied Physics 52 (2013). date_created: 2019-05-20T12:06:04Z date_updated: 2019-05-20T12:08:02Z department: - _id: '151' doi: 10.7567/JJAP.52.07HB03 intvolume: ' 52' issue: 7S language: - iso: eng publication: Japanese Journal of Applied Physics status: public title: Piezoelectric Properties of CuO-Doped (K,Na)NbO3 Lead-Free Ceramics Synthesized with Hydrothermal Powders type: journal_article user_id: '55222' volume: 52 year: '2013' ...