Finite element analysis (FEA) modelling and experimental verification to optimise flexible electronic packaging for e-textiles

Microsystem Technologies - In this paper a three-dimensional model of a novel electronic package has been developed using Finite element analysis to evaluate the shear load, tensile, bending and...     

Adaptive attenuation of unknown and time‐varying narrow band and broadband disturbances

In many classes of applications like active vibration control and active noise control, the disturbances can be characterized by their frequency content and their location in a specific region in the frequency domain. The disturbances can be of narrow band type (simple or multiple) or of broad band type. A model can be associated to these disturbances. The knowledge of this model allows to design an appropriate control system in order to attenuate (or to reject) their effect upon the system to be controlled. The attenuation of disturbances by feedback is limited by the Bode Integral and the ‘water bed’ effect upon the output sensitivity function. In such situations, the feedback approach has to be complemented by a ‘feedforward disturbance compensation’ requiring an additional transducer for obtaining information upon the disturbance. Unfortunately, in most of the situations, the disturbances are unknown and time‐varying and therefore an adaptive approach should be considered. The generic term for adaptive attenuation of unknown and time‐varying disturbances is ‘adaptive regulation’ (known plant model, unknown, and time‐varying disturbance model). The paper will review a number of recent developments for adaptive feedback compensation of multiple unknown and time‐varying narrow band disturbances and for adaptive feedforward compensation of broad band disturbances in the presence of the inherent internal positive feedback caused by the coupling between the compensator system and the measurement of the image of the disturbance. Some experimental results obtained on a relevant active vibration control system will illustrate the performance of the various algorithms presented. Some open research problems will be mentioned in the conclusion. Copyright © 2015 John Wiley & Sons, Ltd.     

Innovative polyelectrolytes/poly(ionic liquid)s for energy and the environment

This paper presents the work carried out within the European project RENAISSANCE‐ITN, which was dedicated to the development of innovative polyelectrolytes for energy and environmental applications. Within the project different types of innovative polyelectrolytes were synthesized such as poly(ionic liquid)s coming from renewable or natural ions, thiazolium cations, catechol functionalities or from a new generation of cheap deep eutectic monomers. Further, macromolecular architectures such as new poly(ionic liquid) block copolymers and new (semi)conducting polymer/polyelectrolyte complexes were also developed. As the final goal, the application of these innovative polymers in energy and the environment was investigated. Important advances in energy storage technologies included the development of new carbonaceous materials, new lignin/conducting polymer biopolymer electrodes, new iongels and single‐ion conducting polymer electrolytes for supercapacitors and batteries and new poly(ionic liquid) binders for batteries. On the other hand, the use of innovative polyelectrolytes in sustainable environmental technologies led to the development of new liquid and dry water, new materials for water cleaning technologies such as flocculants, oil absorbers, new recyclable organocatalyst platforms and new multifunctional polymer coatings with antifouling and antimicrobial properties. All in all this paper demonstrates the potential of poly(ionic liquid)s for high‐value applications in energy and enviromental areas. © 2017 Society of Chemical Industry     

How Benign Structures can Support and Retain Creative Performance in Teams

We suggest that the concept of benign structure is important in understanding how creative leadership can intervene to support and sustain creative performance. We describe this insight with reference to the leadership observed in project teams of various kinds. Our interpretation of the evidence is that creative leadership produces benign structures which help teams pass through two structural barriers (‘press’) that bear on team performance. The weaker barrier requires help on inter-personal relationships. The stronger barrier requires help so that performance levels go beyond established and accepted norms. The benign become most obvious in the application of creative problem solving techniques.     

Book of the Quarter

Book reviewed: Rollo, Christine and Clarke, Thomas, International Best Practice – Case Studies in Knowledge Management     

The impact of oil price shocks: Evidence from the industries of six OECD countries

Most of the studies about the macroeconomic consequences of oil price shocks have been focused on US aggregate data. In contrast to these studies, this paper empirically assesses the dynamic effect of oil price shocks on the output of the main manufacturing industries in six OECD countries. The pattern of responses to an oil price shock by industrial output is diverse across the four European Monetary Union (EMU) countries under consideration (France, Germany, Italy, and Spain), but broadly similar in the UK and the US. Moreover, evidence on cross-industry heterogeneity of oil shock effects within the EMU countries is also reported.     

Microelectromechanical systems vibration powered electromagnetic generator for wireless sensor applications

This paper presents a silicon microgenerator, fabricated using standard silicon micromachining techniques, which converts external ambient vibrations into electrical energy. Power is generated by an electromagnetic transduction mechanism with static magnets positioned on either side of a moving coil, which is located on a silicon structure designed to resonate laterally in the plane of the chip. The volume of this device is approximately 100 mm³. ANSYS finite element analysis (FEA) has been used to determine the optimum geometry for the microgenerator. Electromagnetic FEA simulations using Ansoft’s Maxwell 3D software have been performed to determine the voltage generated from a single beam generator design. The predicted voltage levels of 0.7–4.15 V can be generated for a two-pole arrangement by tuning the damping factor to achieve maximum displacement for a given input excitation. Experimental results from the microgenerator demonstrate a maximum power output of 104 nW for 0.4g (g=9.81 m s⁻¹) input acceleration at 1.615 kHz. Other frequencies can be achieved by employing different geometries or materials.