TY - JOUR A1 - Monkman, Gareth J. A1 - Sindersberger, Dirk A1 - Prem, Nina T1 - Magnetically enhanced photoconductive high voltage control JF - ISSS Journal of Micro and Smart Systems N2 - The recent surge of interest in electrostatic actuators, particularly for soft robotic applications, has placed increasing demands on high voltage control technology. In this respect, optoelectronic bidirectional switching and analogue regulation of high voltages is becoming increasingly important. One common problem is the leakage current due to dark resistance of the material or device used. Another is the physical size of such elements. However, their ability to provide galvanic separation makes them a very attractive alternative to conventional (wired) semiconductor elements. This paper gives an overview of available methods and devices before introducing a concept based on the combination of photoresistive and magnetoresistive effects in Gallium Arsenide that are potentially applicable to other semiconductor materials. KW - GaAs KW - High voltage actuators KW - Magnetoresistance KW - Opto-sensors KW - Photoconduction KW - Soft robotics Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-30606 N1 - Corresponding author: Gareth J. Monkman VL - 11 SP - 317 EP - 328 PB - Springer Nature ER - TY - JOUR A1 - Monkman, Gareth J. A1 - Striegl, Birgit A1 - Prem, Nina A1 - Sindersberger, Dirk T1 - Electrical Properties of Magnetoactive Boron‐Organo‐Silicon Oxide Polymers JF - Macromolecular Chemistry and Physics N2 - The electrical properties of rheopectic magnetoactive composites comprising boron-organo-silicon oxide dielectric matrices containing carbonyl iron microparticles are presented for the first time. The increase in interfacial magnetocapacitance is seen to greatly exceed that experienced when using conventional elastomeric matrices such as polydimethylsiloxane. In addition to the increase in capacitance, a simultaneous and sharp decrease in the parallel electrical resistance over several orders of magnitude is also observed. The effects are time dependent but repeatable. Potential applications include magnetically controlled frequency dependent devices, magnetic sensor systems, weighting elements for neural networks, etc. Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-26488 N1 - Corresponding author: Gareth J. Monkman VL - 221 IS - 4 SP - 1 EP - 8 PB - Wiley ER - TY - JOUR A1 - Prem, Nina A1 - Sindersberger, Dirk A1 - Monkman, Gareth J. T1 - Infrared spectral analysis of low concentration magnetoactive polymers JF - Journal of Applied Polymer Science N2 - This work concerns an area of magnetoactive polymer (MAP) research seldom considered. Traditionally only MAP with high concentrations of magnetic filler (typically between 10 and 90 wt%) have been investigated. This article deals with a hitherto neglected aspect of research, namely MAP containing lower magnetic filler concentrations (1 to 3 wt%). This article utilizes a range of spectroscopic analysis methods (Raman and FTIR) and their applicability to MAP characterization at wavelengths ranging from 2.5 to 25 mu m. Particular attention is paid to low carbonyl iron particle (CIP) concentrations in MAP for which the emergence of capillary doublets at a critical 2 wt% concentration is revealed. This results in measurable magnetic field-dependent changes in IR absorption at a wavelength of 4.255 mu m together with a detectable CO2 susceptibility. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48366. KW - ELASTOMERS KW - magnetism and magnetic properties KW - sensors and actuators KW - spectroscopy Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-25913 SN - 1097-4628 N1 - Corresponding author: Nina Prem VL - 137 IS - 7 SP - 1 EP - 7 PB - Wiley ER - TY - CHAP A1 - Monkman, Gareth J. A1 - Böse, Holger A1 - Ermert, Helmut A1 - Klein, Dagmar A1 - Freimuth, Herbert A1 - Baumann, Míchael A1 - Egersdörfer, Stefan A1 - Bruhns, Otto T. A1 - Meier, Alexander A1 - Raja, Kashif ED - Nerlich, Michael ED - Schächinger, Ulrich T1 - Technologies for Haptic Systems in Telemedicine T2 - Integration of Health Telematics into Medical Practice N2 - The ability to image the elastic properties of tissue is potentially useful in a variety of applications. The field of elastic imaging has grown in response to the Potential use of such information in medical diagnosis. Real time ultrasound elastography represents a recent development in determining strain and elasticity distributions. Nevertheless, commonly used imaging techniques rely on the interpretation of two dimensional visual data displayed on a video screen. In reality however, physicians often prefer tactile exploration making the simultaneous portrayal of both video and haptic information most desirable. Since the 1970's many alphanumeric to tactile data conversion methods have been investigated, mainly with the ultimate aim of assisting the blind. More recently, interest has been directed toward the display of pictures on haptically explorable surfaces - Tactile imaging. Such a system would allow surgeons to examine hard sectors contained within soft tissue, and thereby assist in operations held remotely. The expansion of ultrasound elastography to 3D formats would mean the ability to haptically explore regions of the body normally inaccessible to human hands. For three-dimensional imaging the acquisition of sequential tomographic slices using Elastography, combined with image segmentation, enables the reconstruction, quantification and visualisation of tumour volumes. In a collaborative project between four research Institutes, the aim is to produce a prototype three dimensional tactile displays comprising electrically switchable micromachined cells, whose mechanical moduli are governed by phase changes experienced by electrorheological and/or magnetorheological fluids. This will be integrated with a sensory ultrasonic elastography in order to present the human fingers with controllable surfaces capable of emulating biological tissue, muscle and bone. Y1 - 2003 U6 - https://doi.org/10.3233/978-1-60750-941-7-83 SP - 83 EP - 93 PB - IOS Press ER - TY - JOUR A1 - Böse, Holger A1 - Baumann, Michael A1 - Monkman, Gareth J. A1 - Egersdörfer, Stefan A1 - Tunayar, A. A1 - Freimuth, Herbert A1 - Ermert, Helmut A1 - Khaled, W. T1 - A new ER fluid based haptic actuator system for virtual reality JF - International journal of modern physics / B Condensed matter physics, statistical physics N2 - The concept and some steps in the development of a new actuator system which enables the haptic perception of mechanically inhomogeneous virtual objects are introduced. The system consists of a two-dimensional planar array of actuator elements containing an electrorheological (ER) fluid. When a user presses his fingers onto the surface of the actuator array, he perceives locally variable resistance forces generated by vertical pistons which slide in the ER fluid through the gaps between electrode pairs. The voltage in each actuator element can be individually controlled by a novel sophisticated switching technology based on optoelectric gallium arsenide elements. The haptic information which is represented at the actuator array can be transferred from a corresponding sensor system based on ultrasonic elastography. The combined sensor-actuator system may serve as a technology platform for various applications in virtual reality, like telemedicine where the information on the consistency of tissue of a real patient is detected by the sensor part and recorded by the actuator part at a remote location. Y1 - 2005 U6 - https://doi.org/10.1142/9789812702197_0129 [Titel anhand dieser DOI in Citavi-Projekt übernehmen] VL - 19 IS - 7-9 SP - 1628 EP - 1634 PB - World Scientific Publ. ER - TY - JOUR A1 - Monkman, Gareth J. A1 - Egersdörfer, Stefan A1 - Meier, Alexander A1 - Böse, Holger A1 - Baumann, Michael A1 - Ermert, Helmut A1 - Kahled, W. A1 - Freimuth, Herbert T1 - Technologies for Haptic Displays in Teleoperation JF - Industrial Robot N2 - Since the 1960s many alphanumeric to tactile data conversion methods have been investigated, mainly with the ultimate aim of assisting the blind. More recently, interest has been directed toward the display of pictures on haptically explorable surfaces – tactile imaging – for a range of medical, remote sensing and entertainment purposes. This paper examines the technologies which have been utilised for haptically explorable tactile displays over the past three decades, focussing on those which appear commercially viable in the immediate future. Y1 - 2003 U6 - https://doi.org/10.1108/01439910310506792 SN - 0143-991x VL - 30 IS - 6 SP - 525 EP - 530 PB - Emerald ER - TY - JOUR A1 - Böse, Holger A1 - Monkman, Gareth J. A1 - Freimuth, Herbert A1 - Tunayar, A. A1 - Khaled, W. A1 - Baumann, Michael A1 - Egersdörfer, Stefan A1 - Ermert, Helmut T1 - A new haptic sensor-actuator system based on electrorheological fluids JF - Actuator 2004 : 9th International Conference on New Actuators & 3rd International Exhibition on Smart Actuators and Drive Systems ; Bremen, Germany, 14 - 16 June 2004 Y1 - 2004 PB - HVG Hanseatische Veranstaltungs-GmbH CY - Bremen ER - TY - CHAP A1 - Böse, Holger A1 - Monkman, Gareth J. A1 - Freimuth, Herbert A1 - Tunayar, A. A1 - Ermert, Helmut A1 - Khaled, W. A1 - Baumann, Michael A1 - Egersdörfer, Stefan T1 - A new ER fluid based haptic actuator system for virtual reality T2 - Proceedings of the Ninth International Conference Electrorheological Fluids and Magnetorheological Suspensions (ERMR 2004) : Beijing, China, 29 August - 3 September 2004 Y1 - 2004 SP - 889 EP - 895 PB - World Scientific CY - Singapore ER - TY - CHAP A1 - Tunayar, A. A1 - Klein, Dagmar A1 - Freimuth, Herbert A1 - Böse, Holger A1 - Baumann, Michael A1 - Monkman, Gareth J. A1 - Egersdörfer, Stefan A1 - Ermert, Helmut A1 - Khaled, W. T1 - A tactile array based on electrorheological fluids T2 - Actuator 2004 : 9th International Conference on New Actuators & 3rd International Exhibition on Smart Actuators and Drive Systems, 14-16 June 2004, Bremen, Germany Y1 - 2004 SP - 601 EP - 604 PB - HVG Hanseatische Veranstaltungs-GmbH CY - Bremen ER - TY - CHAP A1 - Böse, Holger A1 - Ermert, Helmut A1 - Tunayar, A. A1 - Monkman, Gareth J. A1 - Baumann, Michael A1 - Kahled, W. A1 - Reichling, S. A1 - Bruhns, Otto T. A1 - Freimuth, Herbert A1 - Egersdörfer, Stefan T1 - A novel haptic sensor-actuator system for virtual reality T2 - Eurohaptics 2004, Munich, Germany, June 5 - 7, 2004 Proceedings of the 4th International Conference EuroHaptics 2004 ; June 5 - 7, 2004, München, Germany Y1 - 2004 SN - 3-9809614-0-0 PB - Inst. of Automatic Control Engineering CY - München ER - TY - CHAP A1 - Böse, Holger A1 - Ermert, Helmut A1 - Tunayar, A. A1 - Monkman, Gareth J. A1 - Baumann, Michael A1 - Kahled, W. A1 - Reichling, S. A1 - Bruhns, Otto T. A1 - Freimuth, Herbert A1 - Egersdörfer, Stefan T1 - A Novel Haptic Sensor-Actuator System for Applications in Virtual Reality T2 - BMBF-Tagung, Leipzig 19.10 February 2004 Y1 - 2004 ER - TY - CHAP A1 - Böse, Holger A1 - Monkman, Gareth J. A1 - Freimuth, Herbert A1 - Klein, Dagmar A1 - Ermert, Helmut A1 - Baumann, Michael A1 - Egersdörfer, Stefan A1 - Bruhns, Otto T. T1 - ER Fluid Based Haptic System for Virtual Reality T2 - Actuator 2002 : 8th International Conference on New Actuators & 2nd International Exhibition on Smart Actuators and Drive Systems ; Bremen, Germany, 10 - 12 June 2002 Y1 - 2002 SP - 351 EP - 354 ET - CD-ROM ER - TY - CHAP A1 - Khaled, W. A1 - Bruhns, Otto T. A1 - Reichling, S. A1 - Böse, Holger A1 - Baumann, Michael A1 - Monkman, Gareth J. A1 - Egersdörfer, Stefan A1 - Meier, Alexander A1 - Klein, Dagmar A1 - Freimuth, Herbert A1 - Ermert, Helmut T1 - A haptic system for virtual reality applications based on ultrasound elastography and electrorheological fluids T2 - Acoustical Imaging (ACIM) N2 - Mechanical properties of biological tissue represent important diagnostic information and are of histological and pathological relevance. Malignant tumors are significantly stiffer and more immobile than surrounding healthy tissue. Hard calcifications in vessels occur due to arteriosclerosis. The problem is, that such information is usually not available or can only be obtained by manual palpation, which is subjective and limited in sensitivity. It requires intuitive assessment and does not allow quantitative documentation. Unfortunately, none of the established medical imaging equipment such as magnetic resonance imaging (MRI) or X-ray computed tomography (CT) can provide direct measure of tissue elasticity. On the one hand a suitable sensor is required for quantitative measurement of mechanical tissue properties. On the other hand there is also some need for a realistic haptic display of such tissue properties. Suitable actuator arrays with high spatial resolution acting in real time are required. A haptic sensor actuator system is presented in this paper including a sensitive sensor part and an actuator array for different applications. The mechanical consistency of an object is to be locally specified using a sensor system and represented perceptibly in a remote position on an actuator system for the user. The sensor system uses ultrasound (US) elastography, whereas the actuator array is based on electrorheological (ER) fluids. KW - Minimal Invasive Surgery KW - Manual Palpation KW - Tactile Display KW - Virtual Reality Application KW - Ultrasound ELASTOGRAPHY Y1 - 2004 SN - 978-90-481-6652-7 SN - 978-1-4020-2402-3 U6 - https://doi.org/10.1007/978-1-4020-2402-3_85 SN - 0270-5117 SN - 2215-1869 VL - 27 SP - 667 EP - 674 PB - Springer CY - Dordrecht ER - TY - CHAP A1 - Khaled, W. A1 - Bruhns, Otto T. A1 - Reichling, S. A1 - Böse, Holger A1 - Baumann, Michael A1 - Monkman, Gareth J. A1 - Egersdörfer, Stefan A1 - Meier, Alexander A1 - Klein, Dagmar A1 - Freimuth, Herbert A1 - Ermert, Helmut T1 - A haptic sensor-actuator-system based on ultrasound elastography and electrorheological fluids for virtual reality applications in medicine T2 - CARS 2003 : computer assisted radiology and surgery ; proceedings of the 17th International Congress and Exhibition London, June 25 - 28, 2003 N2 - Mechanical properties of biological tissue represent important diagnostic information and are of histological relevance (hard lesions, "nodes" in organs: tumors; calcifications in vessels: arteriosclerosis). The problem is, that such information is usually obtained by digital palpation only, which is limited with respect to sensitivity. It requires intuitive assessment and does not allow quantitative documentation. A suitable sensor is required for quantitative detection of mechanical tissue properties. On the other hand, there is also some need for a realistic mechanical display of those tissue properties. Suitable actuator arrays with high spatial resolution and real-time capabilities are required operating in a haptic sensor actuator system with different applications. The sensor system uses real time ultrasonic elastography whereas the tactile actuator is based on electrorheological fluids. Due to their small size the actuator array elements have to be manufactured by micro-mechanical production methods. In order to supply the actuator elements with individual high voltages a sophisticated switching and control concept have been designed. This haptic system has the potential of inducing real time substantial forces, using a compact lightweight mechanism which can be applied to numerous areas including intraoperative navigation, telemedicine, teaching, space and telecommunication. Y1 - 2003 SP - 1354 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Khaled, W. A1 - Ermert, Helmut A1 - Bruhns, Otto T. A1 - Reichling, S. A1 - Böse, Holger A1 - Baumann, Michael A1 - Monkman, Gareth J. A1 - Egersdörfer, Stefan A1 - Meier, Alexander A1 - Klein, Dagmar A1 - Freimuth, Herbert T1 - Haptic sensor-actuator-system based on ultrasound elastography and electrorheological fluids for virtual reality applications in medicine JF - Studies in health technology and informatics, Medicine Meets Virtual Reality (MMVR) N2 - Mechanical properties of biological tissue represent important diagnostic information and are of histological relevance (hard lesions, "nodes" in organs: tumors; calcifications in vessels: arteriosclerosis). The problem is, that such information is usually obtained by digital palpation only, which is limited with respect to sensitivity. It requires intuitive assessment and does not allow quantitative documentation. A suitable sensor is required for quantitative detection of mechanical tissue properties. On the other hand, there is also some need for a realistic mechanical display of those tissue properties. Suitable actuator arrays with high spatial resolution and real-time capabilities are required operating in a haptic sensor actuator system with different applications. The sensor system uses real time ultrasonic elastography whereas the tactile actuator is based on electrorheological fluids. Due to their small size the actuator array elements have to be manufactured by micro-mechanical production methods. In order to supply the actuator elements with individual high voltages a sophisticated switching and control concept have been designed. This haptic system has the potential of inducing real time substantial forces, using a compact lightweight mechanism which can be applied to numerous areas including intraoperative navigation, telemedicine, teaching, space and telecommunication. Y1 - 2003 VL - 11 IS - 94 SP - 144 EP - 150 PB - IOS Press ER - TY - CHAP A1 - Khaled, W. A1 - Reichling, S. A1 - Bruhns, Otto T. A1 - Monkman, Gareth J. A1 - Egersdörfer, Stefan A1 - Baumann, Michael A1 - Böse, Holger A1 - Klein, Dagmar A1 - Freimuth, Herbert A1 - Tunayar, A. A1 - Lorenz, A. A1 - Pessavento, A. A1 - Ermert, Helmut T1 - Palpation imaging using a haptic system for virtual reality applications in medicine T2 - Perspective in image-guided surgery : proceedings of the Scientific Workshop on Medical Robotics, Navigation, and Visualization : RheinAhrCampus Remagen, Germany, 11-12 March Y1 - 2004 SP - 407 EP - 414 PB - World Scientific Publ. CY - Singapore ER - TY - CHAP A1 - Khaled, W. A1 - Reichling, S. A1 - Bruhns, Otto T. A1 - Monkman, Gareth J. A1 - Egersdörfer, Stefan A1 - Baumann, Michael A1 - Böse, Holger A1 - Klein, Dagmar A1 - Freimuth, Herbert A1 - Tunayar, A. A1 - Lorenz, A. A1 - Pessavento, A. A1 - Ermert, Helmut T1 - Palpation Imaging using a Haptic System for Virtual Reality Applications in Medicine T2 - Proceedings of the 12th Annual Medicine Meets Virtual Reality Conference: - Building a Better You: The Next Tools for Medical Education, Diagnosis, and Care. - Medicine Meets Virtual Reality (MMVR) - Newport Beach (California, USA). 2004 Y1 - 2004 ER - TY - CHAP A1 - Khaled, W. A1 - Bruhns, Otto T. A1 - Reichling, S. A1 - Böse, Holger A1 - Baumann, Michael A1 - Monkman, Gareth J. A1 - Egersdörfer, Stefan A1 - Meier, Alexander A1 - Freimuth, Herbert A1 - Tunayar, A. A1 - Ermert, Helmut T1 - A New Haptic Sensor Actuator System for Virtual Reality Applications in Medicine T2 - Medical Image Computing and Computer-Assisted Intervention - MICCAI 2003: 6th International Conference, Montréal, Canada, November 15-18, 2003, Proceedings Y1 - 2003 SN - 978-3540204626 SP - 132 EP - 140 PB - Springer ER - TY - JOUR A1 - Khaled, W. A1 - Bruhns, Otto T. A1 - Reichling, S. A1 - Böse, Holger A1 - Baumann, Michael A1 - Monkman, Gareth J. A1 - Egersdörfer, Stefan A1 - Meier, Alexander A1 - Klein, Dagmar A1 - Freimuth, Herbert A1 - Ermert, Helmut T1 - A haptic system for virtual reality applications based on ultrasound elastography and electrorheological fluids JF - Acoustical Imaging Y1 - 2004 U6 - https://doi.org/10.1007/978-1-4020-2402-3_85 IS - 27 SP - 667 EP - 675 PB - Kluver Academic CY - Dordrecht & New York ER - TY - CHAP A1 - Khaled, W. A1 - Reichling, S. A1 - Bruhns, Otto T. A1 - Ermert, Helmut A1 - Monkman, Gareth J. A1 - Egersdörfer, Stefan A1 - Baumann, Michael A1 - Böse, Holger A1 - Freimuth, Herbert A1 - Tunayar, A. T1 - Palpation imaging using a haptic sensor actuator system for medical applications T2 - Actuator 2004 : 9th International Conference on New Actuators & 3rd International Exhibition on Smart Actuators and Drive Systems, 14-16 June 2004, Bremen, Germany Y1 - 2004 SP - 379 EP - 382 PB - HVG Hanseatische Veranstaltungs-GmbH CY - Bremen ER - TY - GEN A1 - Prem, Nina A1 - Sindersberger, Dirk A1 - Monkman, Gareth J. T1 - Spectroscopic Analysis of Magneto-Active Polymers (MAP) - Poster T2 - DFG-Tagung, Benediktbeuern, September 2017 Y1 - 2017 ER - TY - GEN A1 - Heckner, T. A1 - Kessler, C. A1 - Egersdörfer, Stefan A1 - Monkman, Gareth J. T1 - Computer based platform for tactile actuator analysis T2 - Actuator 2006 : 10th International Conference on New Actuators and 4th International Exhibition on Smart Actuators and Drive Systems, Bremen, Germany, 14 - 16 June 2006 Y1 - 2006 PB - HVG Hanseatische Veranst.-GmbH ER - TY - GEN A1 - Sindersberger, Dirk A1 - Diermeier, Andreas A1 - Monkman, Gareth J. T1 - Investigation of the electrical properties of magneto-active polymers - Poster T2 - DFG-Tagung, Benedikbeuern, September 2016 Y1 - 2016 ER - TY - GEN A1 - Monkman, Gareth J. A1 - Sindersberger, Dirk T1 - Investigation of the electrical properties of magneto-active polymers T2 - DFG-Tagung, Benedikbeuern, September 2015 Y1 - 2015 ER - TY - CHAP A1 - Niklas, Andreas A1 - Hiller, Karl-Anton A1 - Jäger, Andreas A1 - Brandt, M. A1 - Putzger, Jürgen A1 - Ermer, C. A1 - Schulz, Irene A1 - Monkman, Gareth J. A1 - Giglberger, Stephan A1 - Hirmer, Marion A1 - Danilov, Sergey N. A1 - Ganichev, Sergey D. A1 - Schmalz, Gottfried ED - Arenholt-Bindslev, Dorthe ED - Schmalz, Gottfried T1 - In vitro optical detection of simulated blood pulse in a human tooth pulp model T2 - Biocompatibility of Dental Materials Y1 - 2013 PB - Springer CY - Berlin ; Heidelberg ER - TY - JOUR A1 - Prem, Nina A1 - Sindersberger, Dirk A1 - Striegl, Birgit A1 - Böhm, Valter A1 - Monkman, Gareth J. T1 - Shape memory effects using magnetoactive Boron-organo-silicon oxide polymers JF - Macromolecular Chemistry and Physics N2 - Thermomechanical shape memory materials have certain disadvantages when it comes to 3D volumetric reproduction intended for rapid prototyping or robotic prehension. The need to constantly supply energy to counteract elastic retraction forces in order to maintain the required geometry, together with the inability to achieve conformal stability at elevated temperatures, limits the application of thermal shape memory polymers. Form removal also presents problems as most viscoelastic materials do not ensure demolding stability. This work demonstrates how magnetoactive boron−organo−silicon oxide polymers under the influence of an applied magnetic field can be used to achieve energy free sustainable volumetric shape memory effects over extended periods. The rheopectic properties of boron−organo−silicon oxide materials sustain form removal without mold distortion. Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-23205 N1 - Corresponding Author: Gareth J. Monkman VL - 221 IS - 15 SP - 1 EP - 8 PB - Wiley ER - TY - JOUR A1 - Mayer, Matthias A1 - Rabindranath, Raman A1 - Börner, Juliane A1 - Hörner, Eva A1 - Bentz, Alexander A1 - Salgado, Josefina A1 - Han, Hong A1 - Böse, Holger A1 - Probst, Jörn A1 - Shamonin (Chamonine), Mikhail A1 - Monkman, Gareth J. A1 - Schlunck, Günther T1 - Ultra-Soft PDMS-Based Magnetoactive Elastomers as Dynamic Cell Culture Substrata JF - PLoS ONE N2 - Mechanical cues such as extracellular matrix stiffness and movement have a major impact on cell differentiation and function. To replicate these biological features in vitro, soft substrata with tunable elasticity and the possibility for controlled surface translocation are desirable. Here we report on the use of ultra-soft (Young’s modulus <100 kPa) PDMS-based magnetoactive elastomers (MAE) as suitable cell culture substrata. Soft non-viscous PDMS (<18 kPa) is produced using a modified extended crosslinker. MAEs are generated by embedding magnetic microparticles into a soft PDMS matrix. Both substrata yield an elasticity-dependent (14 vs. 100 kPa) modulation of α-smooth muscle actin expression in primary human fibroblasts. To allow for static or dynamic control of MAE material properties, we devise low magnetic field (≈40 mT) stimulation systems compatible with cell-culture environments. Magnetic field-instigated stiffening (14 to 200 kPa) of soft MAE enhances the spreading of primary human fibroblasts and decreases PAX-7 transcription in human mesenchymal stem cells. Pulsatile MAE movements are generated using oscillating magnetic fields and are well tolerated by adherent human fibroblasts. This MAE system provides spatial and temporal control of substratum material characteristics and permits novel designs when used as dynamic cell culture substrata or cell culture-coated actuator in tissue engineering applications or biomedical devices. Y1 - 2013 U6 - https://doi.org/10.1371/journal.pone.0076196 VL - 8 IS - 10 PB - PLOS ER - TY - JOUR A1 - Forster, Eva A1 - Mayer, Matthias A1 - Rabindranath, Raman A1 - Böse, Holger A1 - Schlunck, Günther A1 - Monkman, Gareth J. A1 - Shamonin (Chamonine), Mikhail T1 - Patterning of ultrasoft, agglutinative magnetorheological elastomers JF - Journal of applied polymer science N2 - A low-cost wax-cast molding technique for structuring ultrasoft (Young’s modulus ≤ 40 kPa), agglutinative magnetorheological elastomer (MRE) material is presented. MRE structures ranging from a few millimeters down to the micrometer range with highly reproducible results are possible. Semitransparent MREs are also fabricated and their surfaces modified accordingly. This method opens new possibilities for MREs in biomedical engineering and microfluidic applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 Y1 - 2013 U6 - https://doi.org/10.1002/app.38500 VL - 128 IS - 4 SP - 2508 EP - 2515 PB - Wiley CY - New York, NY ER - TY - JOUR A1 - Diermeier, Andreas A1 - Sindersberger, Dirk A1 - Krenkel, Lars A1 - Rosell, X. C. A1 - Monkman, Gareth J. T1 - Controllable Magnetoactive Polymer Conduit JF - The Open Mechanical Engineering Journal N2 - Objective: Magneto-active Polymers (MAP) are smart materials whose mechanical characteristics, such as elastic and shear moduli, may be controllable by means of an externally applied magnetic field. Methods: Various additives may be used to influence the characteristics of the polymer matrix whilst a suspension of soft and/or hard magnetic particles determine the magnetic properties of the composite. Both pre-cure and post-cure magnetization is possible. Results: A range of control strategies have been investigated for evaluation of the system using fluids of differing kinematic viscosity. Conclusion: Depending on the degree of magnetic field homogeneity, magneto-deformation and magnetostriction contribute to MAP actuation. This paper presents a novel application in the form of a peristaltic MAP tube system, applicable to flow control and pumping of hemorheological fluids in blood circulatory systems for biomedical research purposes. Y1 - 2018 UR - https://www.benthamopen.com/ABSTRACT/TOMEJ-12-192 N1 - Corresponding authro: Gareth J. Monkman VL - 12 IS - 1 SP - 192 EP - 200 PB - Bentham ER - TY - JOUR A1 - Loo, Xuyan A1 - Nagaraju, Bhavana A1 - Pathivada, Sai A1 - Bartsch, Alexander A1 - Schratzenstaller, Thomas A1 - Sattler, Robert A1 - Monkman, Gareth J. T1 - Electrical properties of bisphenol-A-free magnetoactive borosilicate polymers JF - AIP Advances N2 - The recent REACH regulations require the elimination of bisphenol-A and titanium dioxide from commercially available boron-based polymers. This has led to changes in some of the mechanical characteristics, which strongly influence the properties of magnetoactive borosilicate polymers. This work delivers results on the electrical properties and discusses some implications for future research using bisphenol-A and titanium-dioxide-free substitutes. KW - Electrical components KW - Electrical properties and parameters KW - Dielectric properties KW - Electrical resistivity KW - Magnetic materials KW - Viscoelasticity KW - Polymers KW - Non Newtonian fluids KW - Magnetic fluids Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-72936 SN - 2158-3226 N1 - Corresponding author der OTH Regensburg: Gareth J. Monkman VL - 14 IS - 5 PB - AIP Publishing ER - TY - JOUR A1 - Klein, Dagmar A1 - Freimuth, Herbert A1 - Monkman, Gareth J. A1 - Egersdörfer, Stefan A1 - Meier, Alexander A1 - Böse, Holger A1 - Baumann, Michael A1 - Ermert, Helmut A1 - Bruhns, Otto T. T1 - Electrorheological Tactile Elements JF - Mechatronics N2 - The use of ultrasound systems for medical examination and diagnosis is nothing new. The extension of ultrasound techniques for real time elastographic analysis purposes represents a more recent development. Nevertheless, as they stand all such techniques rely on the interpretation of two-dimensional visual data displayed on a video screen. In reality however, a medical doctor will make as much use of exploratory touch as he or she does vision, making the simultaneous portrayal of both video and tactile information most desirable [Böse H, Monkman GJ, Freimuth H, Ermert H. Haptisches Sensor-Aktor-System uaf der grundlage der Echtzeitelastographie sowie von elktro- und magnetorheologischen Materialien “HASASEM” [3]. BMBF Antrag 01 IR A14D, Oktober 2000]. This paper discusses the preliminary tests and basic design parameters for single tactels using electrorheological fluids. The final aim is to produce a prototype three-dimensional tactile display comprising electrically switchable micro-machined cells whose mechanical moduli are governed by phase changes experienced by electrorheological fluids. This will be integrated with the latest elastographic ultrasonic sensor systems in order to present the human fingers with controllable surfaces capable of emulating biological tissue, muscle and bone. Y1 - 2005 U6 - https://doi.org/10.1016/j.mechatronics.2004.05.007 VL - 15 IS - 7 SP - 883 EP - 897 PB - Pergamon CY - Oxford ER - TY - JOUR A1 - Klein, Dagmar A1 - Rensink, D. A1 - Freimuth, Herbert A1 - Monkman, Gareth J. A1 - Egersdörfer, Stefan A1 - Böse, Holger A1 - Baumann, Michael T1 - Modelling the Response of a Tactile Array using an Electrorheological Fluids JF - Journal of Physics D: Applied Physics N2 - This paper reports the first step in the development of a tactile array suitable for the presentation of haptic information in virtual reality. The system is based on the electric field dependence of the viscosity of electrorheological fluids. The simulation, as well as the experimental realization of single tactels is described. The mathematical approach is based on the Eckart model (Eckart W 2000 Continuum Mech. Thermodyn. 12 341–62) and its validity is demonstrated by comparing the resulting yield stress with the experimental results from Wunderlich (2000 Dissertation Universität Erlangen-Nürnberg). Two different tactel designs are realized and the experimental results are compared with numerical simulation. The design of modification B is shown to be applicable for the realization of an actuator array with high spatial resolution. Y1 - 2004 U6 - https://doi.org/10.1088/0022-3727/37/5/023 SN - 1361-6463 SN - 0022-3727 VL - 37 IS - 5 SP - 794 EP - 803 PB - IOP Publ. CY - Bristol ER - TY - CHAP A1 - Diermeier, Andreas A1 - Sindersberger, Dirk A1 - Monkman, Gareth J. T1 - Magneto-Active Polymer Actuator T2 - Actuator 16 : 15th International Conference on New Actuators & 9th International Exhibition on Smart Actuators and Drive Systems : conference proceedings N2 - Magneto-active Polymers (MAP) are closely related to magneto-rheological fluids in that they contain magnetic micro-particles. However, instead of being freely suspended in a carrier fluid they are physically bound within a highly elastic polymer-matrix. The application of an external magnetic field allows changes in the mechanical properties, such as elastic and shear moduli, of the composite material to be achieved. The colossal magneto-rheological effect has been shown to demonstrate changes in Young's modulus by over 1E6 %. Current research concentrates on controllable compliance and the resulting shape memory properties of MAP. This paper deals with recent advancements in this respect, including tubular magneto-active devices with potential applications in medical and other technology. KW - Formgedächtniseffekt KW - Kompositwerkstoff KW - Konzentrat KW - magnetisches Feld KW - magnetorheologische Flüssigkeit KW - Polymer KW - Schermodul Y1 - 2016 SN - 978-3-933339-26-3 SP - 286 EP - 289 PB - WFB CY - Bremen ER - TY - JOUR A1 - Monkman, Gareth J. A1 - Boody, F. P. T1 - Ein Vergleich verschiedene Master-Programme JF - Die Neue Hochschule Y1 - 2003 IS - 1 SP - 12 EP - 13 PB - DUZ Verlags- und Medienhaus GmbH CY - Berlin ER - TY - JOUR A1 - Dillinger, Andrea Elisabeth A1 - Mayer, Matthias A1 - Schneider, Magdalena A1 - Weber, Gregor R. A1 - Goeppner, Corinna A1 - Tamm, Ernst R. A1 - Shamonin (Chamonine), Mikhail A1 - Monkman, Gareth J. A1 - Fuchshofer, Rudolf T1 - Reactive changes in optic nerve astrocytes are mediated by CTGF, TGF beta 2 and increasing substratum stiffness JF - Investigative ophthalmology & visual science N2 - Purpose: Patients with primary open-angle glaucoma (POAG) show a stiffer peripapillary sclera, reactive astrocytes and a remodeled lamina cribrosa (LC). The changes are thought to be mediated by TGFβ2 and its downstream mediator CTGF. Recently we developed a murine glaucoma model by overexpressing CTGF in the anterior eye (βb1CTGF). In this study we investigated the glial lamina region of βb1CTGF mice, and the changes of astrocytes in response to CTGF and TGFβ2 as well as increasing substratum stiffness. Methods: Tangential sections of the glial LC of 2-month-old βb1CTGF mice and their wild-type littermates (WT) were stained with phalloidin and antibodies against GFAP, CTGF and fibronectin (FN). Murine optic nerve (ON) astrocytes from CD1 mice were isolated, cultured and characterized by GFAP staining. The astrocytes were treated with TGFβ2 (1ng/ml) and CTGF (50ng/ml and 100ng/ml). In addition, the cells were seeded on PDMS substrata with different stiffness (10, 30 and 60 kPa). Treated cells were analyzed by Western blotting, real-time RT-PCR and immunohistochemistry. Wound healing assays were performed to analyze migration rate following growth factor treatment. Results: βb1CTGF mice showed a massive increase in CTGF and GFAP in the glial LC when compared with WT mice. Moreover, an increase in FN staining and phalloidin-labeled actin was observed in the peripapillary sclera. Murine ON astrocytes reacted on increased substrate stiffness by increasing the synthesis of GFAP, vimentin and CTGF. Treatment of the cells with TGFβ2 and CTGF led to an enhanced migration rate. In addition, treatment resulted in an increased expression and synthesis of ECM proteins, including FN, tropoelastin, collagen type I and III. The in vitro findings correlated with those seen in the glaucoma mouse model. Conclusions: We conclude that changes in the ECM of LC and peripapillary sclera alter their biomechanical properties and thereby induce reactive changes in resident astrocytes. The reactive changes induced by higher stiffness of their surrounding ECM give rise to a self-amplifying process that includes increased TGFβ2/CTGF signaling and leads to synthesis of ECM and cytoskeletal proteins, a process that in turn augments the stiffness at the optic nerve head (ONH). Such a scenario may finally result in a vicious circle as the causative mechanism for ONH deformation in POAG. Y1 - 2015 VL - 56 IS - 7 PB - ASSOC RESEARCH VISION OPHTHALMOLOGY INC ER - TY - JOUR A1 - Sorokin, Vladislav V. A1 - Stepanov, Gennady V. A1 - Shamonin (Chamonine), Mikhail A1 - Monkman, Gareth J. A1 - Khokhlov, Alexei R. A1 - Kramarenko, Elena Yu T1 - Hysteresis of the viscoelastic properties and the normal force in magnetically and mechanically soft magnetoactive elastomers: Effects of filler composition, strain amplitude and magnetic field JF - Polymer N2 - Hysteresis in dynamic modulus, loss factor and normal forces of magnetoactive elastomers (MAEs) comprising various proportions of small (3-5 mu m) and large (50-60 mu m) ferromagnetic particles are experimentally studied using dynamic torsion performed at a fixed oscillation frequency in varying DC magnetic fields. It is shown that hysteresis is a characteristic feature of MAEs observed both under increasing/decreasing magnetic field strength and increasing/decreasing strain amplitude. This hysteresis is attributed to the specific rearrangement of the magnetic filler network under simultaneously applied magnetic field and shear deformation. Rheological properties of the magnetic filler network formed in the magnetic field and, therefore, the rheological properties of MAEs depend strongly on the filler composition and the magnetic field magnitude. Larger magnetic particles and higher magnetic fields provide stronger magnetic networks. Both factors result in the extension of the linear viscoelastic regime to larger strain amplitudes and lead to higher values of shear storage and loss moduli. It is found that the hysteresis width maximises at an intermediate magnetic field where it is attributed to the balance between elastic and magnetic particle interactions. This is apparently where the most significant restructuring of the magnetic network occurs. The hysteresis width decreases with increasing fraction of large particles in the magnetic filler. The loss factor grows significantly when the magnetic network is physically broken by large strains gamma > 1%. A huge (more than one order of magnitude) increase of normal force at maximum magnetic field strengths is observed. It is predicted that any physical quantity depending on the internal structuring of the magnetic filler should demonstrate hysteresis either with a changing magnetic field and constant deformation amplitude or under variable deformation in a constant magnetic field. (C) 2015 Elsevier Ltd. All rights reserved. KW - BEHAVIOR KW - COMPRESSION KW - Dynamic modulus KW - GELS KW - hysteresis KW - Magnetorheological elastomers KW - magnetostriction KW - MODULUS KW - PARTICLES KW - POLYMER COMPOSITES KW - shear Y1 - 2015 U6 - https://doi.org/10.1016/j.polymer.2015.08.040 VL - 76 SP - 191 EP - 202 PB - Elsevier ER - TY - JOUR A1 - Monkman, Gareth J. A1 - Sindersberger, Dirk A1 - Diermeier, Andreas A1 - Prem, Nina T1 - The magnetoactive electret JF - smart materials and structures N2 - A magnet which adheres to every surface, not only those of ferromagnetic materials, has hitherto been the domain of science fiction. Now for the first time such a novel device exists. The fusion of a permanently magnetized magnetoactive polymer containing hard magnetic particles and an electret enhanced with ferroelectric particles has resulted in the development of a new smart device-the magnetoactive electret. Magnetoactive electrets can be made to exhibit the usual magnetic properties of permanent magnetism together with the electrostatic properties of electrets. This results in simultaneous magnetoadhesion and electroadhesion forces from the same elastomeric element. The biasing field, needed to avoid discontinuities concerned with transition through the zero point in operating curves, is normally provided by means of either a magnetic or an electric field. This novel technology provides both bias options in a single device. KW - 6D printing KW - electret KW - electroadhesion KW - FLUIDS KW - MAGNETIC-FIELD KW - magnetoactive electret KW - magnetoactive polymer KW - magnetoadhesion KW - Magnetorheological elastomers KW - RHEOLOGY Y1 - 2017 U6 - https://doi.org/10.1088/1361-665X/aa738f VL - 26 IS - 7 PB - IOP Publishing ER - TY - JOUR A1 - Monkman, Gareth J. A1 - Sindersberger, Dirk A1 - Prem, Nina A1 - Diermeier, Andreas A1 - Szecsey, Tamara T1 - Dielectric behaviour of magnetic hybrid materials JF - Physical Sciences Reviews N2 - The objectives of this work include the analysis of electrical and magnetic properties of magneto-elastic hybrid materials with the intention of developing new techniques for sensor and actuator applications. This includes the investigation of dielectric properties at both low and high frequencies. The behaviour of capacitors whose dielectrics comprise magnetic hybrid materials is well known. Such interfacial magnetocapacitance can be varied according to magnetic content, magnetic flux density and the relative permittivity of the polymer matrix together with other dielectric content. The basic function of trapping electrical charges in polymers (electrets) is also established technology. However, the combination of magnetoactive polymers and electrets has led to the first electromagnetic device capable of adhering to almost any material, whether magnetically susceptible or not. During the course of this research, in addition to dielectrics, electrically conductive polymers based on (PDMS) matrices were developed in order to vary the electrical properties of the material in a targeted manner. In order to ensure repeatable results, this demanded new fabrication techniques hitherto unavailable. The 3D printing of silicones is far from being a mature technology and much pioneering work was necessary before extending the usual 3 d.o.f. to include orientation about and diffusion of particles in these three axes, thus leading to the concept of 6D printing. In 6D printing, the application of a magnetic field can be used during the curing process to control the particulate distribution and thus the spatial filler particle density as desired. Most of the devices (sensors and actuators) produced by such methods contain levels of carbonyl iron powder (CIP) embedded magnetic filler of up to 70 wt%. Contrary to this, a hitherto neglected research area, namely magnetoactive polymers (MAPs) having significantly lower magnetic particle concentrations (1 to 3 wt% CIP) were also investigated. With filler concentrations lower than 3 wt%, structures are formed which are completely absent at higher filler levels. CIP concentrations in the range of 1wt% demonstrate the formation of toroidal structures. Further development of coherent rings with a compact order results as filler concentrations increase towards 2 wt%. Above 3 wt% the structure eventually disintegrates to the usual random order found in traditional MAP with higher CIP content. Structured samples containing 1%–3 wt% CIP were investigated with the aid of X-ray tomography where solitary ring structures can be observed and eventually the formation of capillary doubles. Over wavelengths ranging from 1 to 25 µm, spectroscopic analysis of thin film MAP samples containing 2 wt% CIP revealed measurable magnetic-field-dependent changes in IR absorption at a wavenumber 2350 (λ = 4.255 µm). This was found to be due to the diamagnetic susceptibility of atmospheric carbon dioxide (CO2). Consequently, the first potential application for sparse matrix MAPs was found. KW - cappillary doublet KW - diamagnetic KW - elastomer dielectric KW - FTIR KW - interfacial magnetocapacitance KW - magnetoactive polymer KW - PDMS KW - toroid Y1 - 2021 U6 - https://doi.org/10.1515/psr-2019-0121 N1 - Corresponding author: Gareth J. Monkman VL - 7 IS - 10 SP - 1169 EP - 1185 PB - de Gruyter ER - TY - JOUR A1 - Prem, Nina A1 - Sindersberger, Dirk A1 - Monkman, Gareth J. T1 - Mini-Extruder for 3D Magnetoactive Polymer Printing JF - Advances in Materials Science and Engineering N2 - This work describes the development of a new miniature extruder, essential to cavity-free 3D printing of silicone-based smart materials. This makes the 3D printing of magnetoactive and electroactive polymer soft robotic components and devices directly from CAD data possible. The special feature of such an extruder is that it is designed for use with addition-crosslinking RTV-2 silicones, including solid particulate additives. The extruder merges the respective components automatically during extrusion which obviates the need for premixing and vacuum evacuation. Problems associated with inhomogeneities and unwanted cavity production are consequently eliminated. Rheological details necessary to the design, together with some preliminary performance results, are presented. Y1 - 2019 U6 - https://doi.org/10.1155/2019/8715718 N1 - Corresponding author: Gareth J. Monkman SP - 1 EP - 8 PB - HINDAWI ER - TY - JOUR A1 - Kreitmeier, Florian A1 - Chashin, Dmitri V. A1 - Fetisov, Yuri K. A1 - Fetisov, Leonid Y. A1 - Schulz, Irene A1 - Monkman, Gareth J. A1 - Shamonin (Chamonine), Mikhail T1 - Nonlinear Magnetoelectric Response of Planar Ferromagnetic-Piezoelectric Structures to Sub-Millisecond Magnetic Pulses JF - Sensors N2 - The magnetoelectric response of bi- and symmetric trilayer composite structures to pulsed magnetic fields is experimentally investigated in detail. The structures comprise layers of commercially available piezoelectric (lead zirconate titanate) and magnetostrictive (permendur or nickel) materials. The magnetic-field pulses have the form of a half-wave sine function with duration of 450 µs and amplitudes ranging from 500 Oe to 38 kOe. The time dependence of the resulting voltage is presented and explained by theoretical estimations. Appearance of voltage oscillations with frequencies much larger than the reciprocal pulse length is observed for sufficiently large amplitudes (~1-10 kOe) of the magnetic-field pulse. The origin of these oscillations is the excitation of bending and planar acoustic oscillations in the structures. Dependencies of the magnetoelectric voltage coefficient on the excitation frequency and the applied magnetic field are calculated by digital signal processing and compared with those obtained by the method of harmonic field modulation. The results are of interest for developing magnetoelectric sensors of pulsed magnetic fields as well as for rapid characterization of magnetoelectric composite structures. Y1 - 2012 U6 - https://doi.org/10.3390/s121114821 N1 - Corresponding author: Mikhail Shamonin VL - 12 IS - 11 SP - 14821 EP - 14837 PB - MDPI CY - Basel ER - TY - JOUR A1 - Monkman, Gareth J. A1 - Sindersberger, Dirk A1 - Prem, Nina A1 - Szecsey, Tamara T1 - Smart Stiction JF - Robotics & Automation Engineering Journal N2 - Soft robotics could loosely be described as the engineering science of expanded dexterity through controllable flexibility. The exploitation of controllable compliance through the judicious choice of soft flexible members, as opposed to a finite number of rigid kinematic joints, can result in greater dexterity without compromising simplicity. One example is the replacement of segmented mechanical legs with simple compliant material eruciform prolegs. To achieve this in robotics, without introducing additional mechanical joints, mobile surfaces with switchable coefficients of friction is essential. This paper explains how, using silicone based smart materials, the rapid alternation between kinematic and static friction (stiction) may be achieved. Y1 - 2019 U6 - https://doi.org/10.19080/RAEJ.2019.04.555641 N1 - Corresponding author: Gareth J. Monkman VL - 4 IS - 4 PB - Juniper Publishers ER - TY - JOUR A1 - Sindersberger, Dirk A1 - Prem, Nina A1 - Monkman, Gareth J. T1 - Structure formation in low concentration magnetoactive polymers JF - AIP advances N2 - This paper concerns recent research into the autonomous formation of micro-structures in low carbonyl iron powder (CIP) concentration magneto active polymers (MAP). Higher concentrations of CIP show an isotropic distribution of magnetic filler throughout the entire sample, while autonomous structure formation is possible at mass concentrations lower than 3%. The formation of micro-toroids commences as CIP concentration approaches 1% wt. Further development of coherent rings with a defined order follow as CIP concentrations increase toward 2% wt, whilst exceeding 3% wt leads to the same isotropic distribution found in higher concentration MAP. Structured samples containing between 1% wt and 3% wt CIP were investigated using X-Ray tomography where solitary structures could clearly be observed. The ring structures represent microinductivities whose geometries can be manipulated during fabrication. In addition, these structures are magnetic field sensitive. This is not only relevant to applications in the GHz and THz areas but recent research has revealed implications for optical, thermal, acoustic and even chemical MAP sensors. (C) 2019 Author(s). Y1 - 2019 U6 - https://doi.org/10.1063/1.5079997 N1 - Corresponding author: Dirk Sindersberger VL - 9 IS - 3 PB - AIP Publishing ER - TY - JOUR A1 - Chen, Rui A1 - Zhang, Zhuo A1 - Song, Ruizhou A1 - Fang, Cheng A1 - Sindersberger, Dirk A1 - Monkman, Gareth J. A1 - Guo, Jianglong T1 - Time-dependent electroadhesive force degradation JF - Smart Materials and Structures N2 - This paper concerns a comprehensive investigation of time-dependent electroadhesion (EA) force degradation. EA shear force tests on different object materials (a PET, glass, ABS, and wood plate) have shown that force degradation was dominated by residual polarization charges trapped in the EA pad dielectric rather than in the substrate dielectric from which the object to be prehended is made. In order to explain this dynamic physical phenomenon, a model of dielectric polarization and depolarization has been proposed. According to the derived relationship between EA force and discharge time, three different methods intended to mitigate this problem has been compared: (1) the natural discharge method, (2) the high voltage resistor discharge method, and (3) the discharge prior to field polarity reversal method. These methods are useful for generating repeatable and stable EA forces, which are required for the characterization of EA pads and their subsequent employment in material handling, mobile robot crawling and climbing tasks. Y1 - 2020 U6 - https://doi.org/10.1088/1361-665X/ab79b5 VL - 29 IS - 5 PB - IOP Publishing ER - TY - JOUR A1 - Schmidt, Henrik A1 - Straub, Benedikt B. A1 - Sindersberger, Dirk A1 - Bröckel, Ulrich A1 - Monkman, Gareth J. A1 - Auernhammer, Günter T1 - Collision and separation of nickel particles embedded in a Poly dimethylsiloxan matrix under a rotating magnetic field: A strong magneto active function JF - Colloid and Polymer Science N2 - In order to function as soft actuators, depending on their field of use, magnetorheological elastomers (MREs) must fulfill certain criteria. To name just a few, these can include rapid response to external magnetic fields, mechanical durability, mechanical strength, and/or large deformation. Of particular interest are MREs which produce macroscopic deformation for small external magnetic field variations. This work demonstrates how this can be achieved by just a small change in magnetic field orientation. To achieve this, (super)paramagnetic nickel particles of size ≈ 160 μm were embedded in a non-magnetic polydimethylsiloxan (PDMS) (661–1301 Pa) and their displacement in a stepwise rotated magnetic field (170 mT) recorded using a video microscope. Changes in particle aggregation resulting from very small variations in magnetic field orientation led to the observation of a new strongly magneto-active effect. This configuration is characterized by an interparticle distance in relation to the angle difference between magnetic field and particle axis. This causes a strong matrix deformation which in turn demonstrates hysteresis on relaxation. It is shown that the occurrence strongly depends on the particle size, particle distance, and stiffness of the matrix. Choosing the correct parameter combination, the state can be suppressed and the particle-matrix system demonstrates no displacement or hysteresis. In addition, evidences of non-negligible higher order magnetization effects are experimentally ascertained which is qualitatively in agreement with similar, already theoretically described, particle systems. Even at larger particle geometries, the new strongly magneto-active configuration is preserved and could create macroscopic deformation changes. Y1 - 2021 U6 - https://doi.org/10.1007/s00396-020-04784-4 VL - 299 SP - 955 EP - 967 PB - Springer ER - TY - GEN ED - Monkman, Gareth J. T1 - Soft robotics Y1 - 2022 SN - 978-981-5051-72-8 SN - 9789815051735 U6 - https://doi.org/10.2174/97898150517281220101 PB - Bentham Science CY - Singapore ER - TY - CHAP A1 - Sefl, Ondrej A1 - Prochazka, Radek A1 - Haller, Rainer A1 - Monkman, Gareth J. T1 - Alternative Approach to Optical Detection of Partial Discharges in Air T2 - 2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP): 12-15 Dec. 2021, Vancouver, BC, Canada N2 - This article compares the standard electrical method of partial discharge detection with a novel optical detection method based on silicon photomultipliers. A third, complementary, single-loop antenna method is added to represent the ultra-high frequency method commonly used in gas-insulated switchgear/lines. A trio of air-insulated electrode designs that simulate the fundamental fault/discharge types in gaseous insulation (protrusion – corona discharge, floating conductive particle, surface discharges) are employed. Phase-resolved partial discharge activity patterns are compiled for each electrode design. The patterns are analyzed using spatial statistics and the interpretation of the obtained data trends explained by means of an example. Ultimately, the consistency and reliability of discharge detection by the optical methods for each fault/discharge type are evaluated, and suggestions for improvement are made. KW - gas insulated switchgear KW - loop antennas KW - partial discharges KW - photomultipliers KW - reliability KW - statistical analysis KW - surface discharges Y1 - 2021 SN - 978-1-6654-1907-9 U6 - https://doi.org/10.1109/CEIDP50766.2021.9705350 SN - 2576-2397 SP - 324 EP - 327 PB - IEEE ER - TY - CHAP A1 - Sindersberger, Dirk A1 - Prem, Nina A1 - Monkman, Gareth J. A1 - Zimmermann, Klaus ED - Schlaak, Helmut T1 - Self-Sensing Electroadhesive Polymer Gripper with Magnetically Controllable Surface Geometry T2 - Actuator 2021, International Conference and Exhibition on New Actuator Systems and Applications: GMM conference, February 17-19, 2021, online event N2 - Compared to conventional end effectors, electro-adhesive grippers enable the handling of sensitive, soft or air-permeable materials [1]. The prehension force is based on a strong electric field generated by electrodes resulting in a polarisation of the dielectric and the generation of mirror charges in the workpiece. When the electrode supply voltage is deactivated, the electric field drops,but an electrostatic field remains due to remanent polarisation of the dielectric. The residual charge on the gripper surface reduces only slowly and in combination with other influencing factors can prevent the workpieces from being ejected temporarily or completely. In this work a solution to this problem is presented by means of gripper surface deforming caused by the applicat ion of a magnetic field to a magneto- active polymer (MAP) actuator. The in-creased distance between the workpiece and the dielectric enables precise and controlled ejection. In addition to compliance and deformability, the employment of soft smart materials enables the integration of self-sens-ing mechanisms for the measurement of surface deformation. The embedding of electrically conductive flexible electrodes within the soft silicone dielectric sup port such movements and serves as the n ecessary electrodes for electroadhesion. Since the implementation of the end effectoris based entirely on soft materials, the self-sensing magnetically controllable electroadhesive gripper (SMEG) can be produced in a shape deposition manufacturing (SDM) process [2], [3] and is highly applicable to the field of soft robotics. Y1 - 2021 SN - 9783800754540 U6 - https://doi.org/10.1002/macp.201800222 SP - 318 EP - 320 PB - VDE VERLAG CY - Berlin; Offenbach ER - TY - JOUR A1 - Sorokin, Vladislav V. A1 - Ecker, Eva A1 - Stepanov, Gennady V. A1 - Shamonin (Chamonine), Mikhail A1 - Monkman, Gareth J. A1 - Kramarenko, Elena Yu A1 - Khokhlov, Alexei R. T1 - Experimental study of the magnetic field enhanced Payne effect in magnetorheological elastomers JF - Soft Matter N2 - The dynamic modulus and the loss factor of magnetorheological elastomers (MREs) of various compositions and anisotropies are studied by dynamic torsion oscillations performed in the absence and in the presence of an external magnetic field. The emphasis is on the Payne effect, i.e. the dependence of the elastomer magnetorheological characteristics on the strain amplitude and their evolution with cyclically increasing and decreasing strain amplitudes. MREs are based on two silicone matrices differing in storage modulus (soft, G' similar to 10(3) Pa, and hard, G' similar to 10(4) Pa, matrices). For each matrix, the concentration of carbonyl iron particles with diameters of 3-5 mu m was equal to 70 and 82 mass% (22 and 35 vol%, respectively) in the composite material. Samples for each filler content, isotropic and aligned-particles, are investigated. It is found that the Payne effect significantly increases in the presence of an external magnetic field and varies with the cyclical loading which reaches saturation after several cycles. The results are interpreted as the processes of formation-destruction-reformation of the internal filler structure under the simultaneously applied mechanical force and magnetic field. Impacts of matrix elasticity and magnetic interactions on the filler alignment are elucidated. KW - BEHAVIOR KW - CARRAGEENAN KW - DAMPERS KW - MODEL KW - SEALS KW - SENSITIVE ELASTOMERS KW - Shear modulus KW - VISCOELASTIC PROPERTIES KW - WIDE-RANGE MODULATION Y1 - 2014 U6 - https://doi.org/10.1039/c4sm01738b VL - 10 IS - 43 SP - 8765 EP - 8776 PB - ROYAL Society of CHEMISTRY ER - TY - JOUR A1 - Chen, Rui A1 - Song, Ruizhou A1 - Zhang, Zhuo A1 - Bai, Long A1 - Liu, Fuqiang A1 - Jiang, Pei A1 - Sindersberger, Dirk A1 - Monkman, Gareth J. A1 - Guo, Jianglong T1 - Bio-Inspired Shape-Adaptive Soft Robotic Grippers Augmented with Electroadhesion Functionality JF - Soft Robotics N2 - Soft robotic grippers (SRGs) have been extensively employed in robotic grasping and manipulation applications due to the fact that they are beneficial for pick-and-place of difficult-to-handle and delicate objects with various geometries and stiffness in a comfortable and safer way. This article presents a bio-inspired and shape-adaptive SRG augmented with electroadhesion (EA) functionality, FinEA, by a cost-effective combination of a Fin Ray structured two-fingered SRG with two soft-stretchable EA pads. The EA pads were manufactured by screen printing a layer of electrically conductive and elastomeric carbon black powder mixed with polydimethylsiloxane onto a dielectric substrate. The compliant Fin Ray fingers, composed of soft longitudinal beams and rigid cross beams, were structurally optimized by the finite element method using ABAQUS/CAE based on three key parameters: the open angle of the longitudinal beams, the spacing between the cross beams, and the incline angle of the cross beams. The soft beams were produced by a traditional soft lithography method, whereas the rigid cross beams were three-dimensionally printed. The resultant FinEA grippers were capable of lifting not only flat/thin materials without distorting them due to the employment of EA, but also concave and convex objects due to the passively shape-adaptive Fin Ray structure and the EA functionality. In addition, the proposed FinEA grippers were able to grasp delicate materials and objects whose diameters are larger than the overall gripper length. Furthermore, 65% more weight in shear were picked up by the FinEA gripper when 4 kV was applied compared with 0 V. The FinEA concept provides useful and alternative solution for controllable adhesion-based SRGs and may facilitate the inspiration and development of future SRGs with added functionality and enhanced versatility. KW - electroadhesion KW - Fin Ray structure KW - shape-adaptive KW - soft robotic grippers Y1 - 2019 U6 - https://doi.org/10.1089/soro.2018.0120 VL - 6 IS - 6 SP - 701 EP - 712 PB - Mary Ann Liebert ER - TY - JOUR A1 - Diermeier, Andreas A1 - Sindersberger, Dirk A1 - Angele, Peter A1 - Kujat, Richard A1 - Monkman, Gareth J. T1 - Sensor system for use with low intensity pulsed ultrasound JF - Sensor review N2 - Purpose Ultrasound is a well-established technology in medical science, though many of the conventional measurement systems (hydrophones and radiation force balances [RFBs]) often lack accuracy and tend to be expensive. This is a significant problem where sensors must be considered to be "disposable" because they inevitably come into contact with biological fluids and expense increases dramatically in cases where a large number of sensors in array form are required. This is inevitably the case where ultrasound is to be used for the in vitro growth stimulation of a large plurality of biological samples in tissue engineering. Traditionally only a single excitation frequency is used (typically 1.5 MHz), but future research demands a larger choice of wavelengths for which a single broadband measurement transducer is desirable. Furthermore, because of implementation conditions there can also be large discrepancies between measurements. The purpose of this paper deals with a very cost-effective alternative to expensive RFBs and hydrophones. Design/methodology/approach Utilization of cost-effective piezoelectric elements as broadband sensors. Findings Very effective results with equivalent (if not better) accuracy than expensive alternatives. Originality/value This paper concentrates on how very cost-effective piezoelectric ultrasound transducers can be implemented as sensors for ultrasound power measurements with accuracy as good, if not better than those achievable using radiation force balances or hydrophones. KW - BALANCE KW - Hydrophone KW - Mesenchymal stem cell KW - Piezoelectric transducer KW - Radiation force balance KW - Sensors KW - therapy KW - Tissue engineering KW - Ultrasound Y1 - 2019 U6 - https://doi.org/10.1108/SR-11-2018-0304 SN - 0260-2288 VL - 39 IS - 6 SP - 828 EP - 834 PB - Emerald ER -