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 - 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 - 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 - TY - JOUR A1 - Sindersberger, Dirk A1 - Prem, Nina A1 - Monkman, Gareth J. T1 - Self-assembling structure formation in low-density magnetoactive polymers JF - Journal of Applied Polymer Science N2 - The formation of microstructures in magnetoactive polymers (MAPs) is a recently discovered phenomenon found only with very low filler particle concentrations (less than 3 wt %). Due to the degassing process, filler particles collect around an ascending bubble, which dissolves at a certain point leaving particulate rings within the matrix. The formation of toroidal microstructures commences as filler concentration approaches 1 wt %. The development of coherent parallel aligned rings with a compact order continues as particle concentrations increase toward 2 wt %. Between 2 and 3 wt % capillary doublets develop, while mass percentages higher than 3% result in increasing entropy as the random order of particle agglomeration found in higher concentration MAP dominates. Self-structured samples of different filler material and concentrations between 1 and 3 wt % have been investigated using X-ray tomography, where the emerging structures can be observed and visualized. The ring structures resulting from this research represent microinductivities which can be fabricated in a targeted manner, thus enabling new applications in the high-frequency radio field. Furthermore, these anisotropic, but well-organized, structures have magnetic field-dependent implications for optical, thermal, acoustic, and medical applications. KW - composites KW - ELASTOMERS KW - magnetism and magnetic properties KW - Particle KW - PERMEABILITY KW - self-assembly KW - sensors and actuators KW - VISCOELASTIC PROPERTIES KW - X-ray Y1 - 2019 U6 - https://doi.org/10.1002/app.48291 VL - 137 IS - 3 PB - Wiley ER - TY - JOUR A1 - Knörzer, S. A1 - Hiller, Karl-Anton A1 - Brandt, M. A1 - Niklas, Andreas A1 - Putzger, Jürgen A1 - Monkman, Gareth J. A1 - Danilov, Sergey N. A1 - Ganichev, Sergey D. A1 - Schulz, Irene A1 - Schmalz, Gottfried T1 - Detection of pulsed blood flow through a molar pulp chamber and surrounding tissue in vitro JF - Journal of Clinical Oral Investigations N2 - OBJECTIVES Due to severe limitations of dental pulp sensitivity tests, the direct recording of pulsed blood flow, using photoplethysmography (PPG), has been proposed. In vivo evaluation is methodologically difficult and in vitro models have hitherto been adversely influenced by shortcomings in emulating the in vivo situation. Consequently, the aim of this study was to test an improved data acquisition system and to use this configuration for recording pulsed blood in a new model. MATERIALS AND METHODS We introduced a PPG signal detection system by recording signals under different blood flow conditions at two wavelengths (625 and 940 nm). Pulsed blood flow signals were measured using an in vitro model, containing a molar with a glass pulp and a resin socket, which closely resembled in vivo conditions with regard to volumetric blood flow, pulp anatomy, and surrounding tissue. RESULTS The detection system showed improved signal strength without stronger blanketing of noise. On the tooth surface, it was possible to detect signals emanating from pulsed blood flow from the glass pulp and from surrounding tissue at 625 nm. At 940 nm, pulp derived signals were recorded, without interference signals from surrounding tissue. CONCLUSION The PPG-based method has the potential to detect pulsed blood flow in small volumes in the pulp and (at 625 nm) also in adjacent tissues. CLINICAL RELEVANCE The results show the need for clear differentiation of the spatial origins of blood flow signals of any vitality test method to be applied to teeth. KW - Dental Pulp KW - Dental Pulp Cavity KW - Dental Pulp Test KW - Laser-Doppler Flowmetry KW - Molar Y1 - 2019 U6 - https://doi.org/10.1007/s00784-018-2530-y VL - 23 IS - 3 SP - 1121 EP - 1132 PB - Springer Nature ER - TY - JOUR A1 - Zimmermann, Klaus A1 - Chavez Vega, Jhohan Harvey A1 - Becker, Tatiana I. A1 - Witte, Hartmut A1 - Schilling, Cornelius A1 - Köhring, Sebastian A1 - Böhm, Valter A1 - Monkman, Gareth J. A1 - Prem, Nina A1 - Sindersberger, Dirk A1 - Lutz, I. I. A1 - Merker, Lukas T1 - An approach to a form-adaptive compliant gripper element based on magneto-sensitive elastomers with a bioinspired sensorized surface JF - Problems of Mechanics Y1 - 2019 SN - 1512-0740 VL - 75 IS - 2 SP - 23 EP - 38 PB - Georgian Technical University CY - Tbilisi ER -