TY - GEN A1 - Düsberg, Felix A1 - Bachmann, Michael A1 - Edler, Simon A1 - Pahlke, Andreas A1 - Langer, Christoph A1 - Prommesberger, Christian A1 - Schreiner, Rupert A1 - Bunert, Erik A1 - Wendt, Cornelius A1 - Zimmermann, Stefan T1 - Novel Non-Radiative Electron Source T2 - 43rd International Symposium of Capillary Chromatography & 16h GC x GC Symposium 2019 N2 - Recently a non-radioactive electron capture detector based on a thermionic electron emitter has been demonstrated [1]. Using field emitter arrays (FEAs) would yield non-radioactive portable low power devices with fast switching capability. By combining FEAs with a vacuum-sealed housing and an electron transparent membrane window, such electron sources can be operated in an ambient pressure environment. Y1 - 2019 ER - TY - JOUR A1 - Becker, Tatiana I. A1 - Böhm, Valter A1 - Chavez, Jhohan A1 - Odenbach, Stefan A1 - Raikher, Yuriy L. A1 - Zimmermann, Klaus T1 - Magnetic-field-controlled mechanical behavior of magneto-sensitive elastomers in applications for actuator and sensor systems JF - Archive of Applied Mechanics N2 - The development of actuator and sensor systems with complex adaptive behavior and operating sensitivity is one of the actual scientific challenges. Smart materials like magneto-sensitive elastomers (MSEs) offer great potential for designing such intelligent devices, because they possess unique magnetic-field-dependent properties. The present paper deals with investigations of the free and forced vibrational behavior displayed by cantilever beams of MSEs containing magnetically soft particles in a uniform magnetic field. It is shown experimentally as well as theoretically that the first bending eigenfrequency of MSE beams depends strongly on the strength of an applied magnetic field. The proposed magneto-mechanical model is based on the vibrational dynamics of thin rods and predicts reliably the amplitude–frequency characteristics depending on the geometric configuration of the MSE and its material parameters. It is found that the vibration response of an MSE beam under kinematic excitation of its base can be modified indirectly by a magnetic field control due to the change of the vibration characteristics. As a result, the resonance can occur in different ranges of the excitation frequency. The dependencies of the amplification ratio on the excitation frequency are obtained experimentally and compared with the result provided by the theoretical model. Moreover, investigations on the potential use of the field-induced plasticity effect of MSEs in form-fit gripper applications are presented. This effect can be used to realize shape adaptable system parts. It is found that the mechanical properties of each component and its concentration within the mixture have an impact on the mechanical behavior of the whole MSE compound. Such parameters as the strength of magnetic field and geometry of the MSE sample have influence on the quality of shape adaptation. The evidence presented provides a good basis for the realization of MSE-based actuator and sensor systems with adaptable sensitivity. Y1 - 2019 U6 - https://doi.org/10.1007/s00419-018-1477-4 VL - 89 IS - 1 SP - 133 EP - 152 PB - Springer Nature ER - TY - JOUR A1 - Schümann, Malte A1 - Morich, J. A1 - Kaufhold, T. A1 - Böhm, Valter A1 - Zimmermann, Klaus A1 - Odenbach, Stefan T1 - A mechanical characterisation on multiple timescales of electroconductive magnetorheological elastomers JF - Magnetism and Magnetic Materials N2 - Magnetorheological elastomers are a type of smart hybrid material which combines elastic properties of a soft elastomer matrix with magnetic properties of magnetic micro particles. This leads to a material with magnetically controllable mechanical properties of which the magnetorheological effect is the best known. The addition of electroconductive particles to the polymer mix adds electrical properties to the material behaviour. The resulting electrical resistance of the sample can be manipulated by external magnetic fields and mechanical loads. This results in a distinct interplay of mechanical, electrical and magnetic effects with a highly complex time behaviour. In this paper a mechanical characterisation on multiple time scales was conducted to get an insight on the short and long-term electrical and mechanical behaviour of this novel material. The results show a complex resistivity behaviour on several timescales, sensitive to magnetic fields and strain velocity. The observed material exhibits fatigue and relaxation behaviour, whereas the magnetorheological effect appears not to interfere with the piezoresistive properties. Y1 - 2018 U6 - https://doi.org/10.1016/j.jmmm.2018.01.029 VL - 453 IS - May SP - 198 EP - 205 PB - Elsevier ER - TY - CHAP A1 - Herdl, Florian A1 - Kueddelsmann, Maximillian J. A1 - Schels, Andreas A1 - Bachmann, Michael A1 - Edler, Simon A1 - Wohlfartsstätter, Dominik A1 - Düsberg, Felix A1 - Prugger, Alexander A1 - Dillig, Michael A1 - Dams, Florian A1 - Schreiner, Rupert A1 - Coileáin, Cormac Ó. A1 - Zimmermann, Stefan A1 - Pahlke, Andreas A1 - Duesberg, Georg S. T1 - Characterization and Operation of Graphene-Oxide-Semiconductor Emitters at Atmospheric Pressure Levels T2 - 2023 IEEE 36th International Vacuum Nanoelectronics Conference (IVNC), 10-13 July 2023, Cambridge, MA, USA N2 - In recent years Graphene-Oxide-Semiconductor (GOS) electron emitters have attracted a lot of interest due to their outstanding durability in modest vacuum conditions. However, the performance at ambient pressure remains largely unexplored. In this study GOS-emitters are characterized in nitrogen and air at atmospheric pressure, and compared with their vacuum characteristics. For this purpose, lifetime and IV-characteristics measurements are shown. Furthermore, the GOS-emitter was operated as an ionization source for ion mobility spectrometry (IMS) at ambient conditions. KW - durability KW - graphene compounds KW - ion mobility KW - semiconductor-insulator boundaries Y1 - 2023 SN - 979-8-3503-0143-4 U6 - https://doi.org/10.1109/IVNC57695.2023.10188974 SP - 14 EP - 16 PB - IEEE ER - TY - JOUR A1 - Kopper, Andreas A1 - Fürstenau, Daniel A1 - Zimmermann, Stephan A1 - Klotz, Stefan A1 - Rentrop, Christopher A1 - Rothe, Hannes A1 - Strahringer, Susanne A1 - Westner, Markus T1 - Shadow IT and Business-Managed IT: A Conceptual Framework and Empirical Illustration JF - International Journal of IT/Business Alignment and Governance (IJITBAG) N2 - Research on Shadow IT is facing a conceptual dilemma in cases where previously “covert” systems developed by business entities are integrated in the organizational IT management. These systems become visible, are thus not “in the shadows” anymore, and subsequently do not fit to existing definitions of Shadow IT. Practice shows that some information systems share characteristics of Shadow IT but are created openly in alignment with the IT organization. This paper proposes the term “Business-managed IT” to describe “overt” information systems developed or managed by business entities and distinguishes it from Shadow IT by illustrating case vignettes. Accordingly,our contribution is to suggest a concept and its delineation against other concepts. In this way, IS researchers interested in IT originated from or maintained by business entities can construct theories with a wider scope of application that are at the same time more specific to practical problems. In addition, the terminology allows to value potentially innovative developments by business entities more adequately. KW - Alignment KW - Business-managed IT KW - IT governance KW - Shadow IT KW - Unternehmen KW - Informationstechnik KW - Datensicherung KW - Organizational IT management Y1 - 2018 U6 - https://doi.org/10.4018/IJITBAG.2018070104 VL - 9 IS - 2 SP - 53 EP - 71 PB - IGI Global ER -