The potential use of piezoelectric bimorph actuators in minimally invasive surgery suture-needle grasper/holder applications is explored computationally. Upon defining the design/functional requirements for such surgical tools, a finite element analysis of the underlying piezoelectric boundary value problem is combined with the genetic algorithm optimization routine to arrive at an optimal morp...

2014 In the preparation of piezoelectric materials, it is generally necessary to apply to an insulating material a high poling electric field. During this operation various processes can take place which can strongly influence the performances of the obtained transducer. Until now experience and know how have been the leading factors for the determination of the poling parameters. This may chan...

In this study micro-sensors were employed to analyse macro-kinematic parameters during a classical cross-country skiing competition (10 km, 2-lap). Data were collected from eight male participants during the Australian championship competition wearing a single micro-sensor unit (MinimaxX™, S4) positioned on their upper back. Algorithms and visual classification were used to identify skiing sub-...

Due to the complexity of movement in cross-country skiing (XCS), the muscle activation patterns are not well elucidated. Previous studies have applied surface electromyography (SEMG); however, recent gains in three-dimensional (3D) imaging techniques such as positron emission tomography (PET) have rendered an alternative approach to investigate muscle activation. The purpose of the present stud...

2014 In stretched poly(vinylidene fluoride) films, the transition from unpolar 03B1-form to a polar form (03B1p) is produced by pohng at 80 °C by an electric field of 1 MV/cm. This oriented form has the same lattice constants as 03B1-form but is associated with extra diffuse reflections. This form and the diffuse reflections disappear by annealing above 170 °C and give an oriented and more stab...

Any attempt made to separate energy into electrical and mechanical parts may lead to inconsistencies as they do not necessarily decouple. This is illustrated by application of the energy density function in the linear theory of piezoelasticity. By assuming that a critical energy density function prevails at the onset of crack initiation, it is possible to establish the relative size of an inner...

This paper demonstrates a new power cycle for direct conversion of mechanical energy into electrical energy under a thermal bias. The cycle consisted sequentially of (i) an electric poling process under zero stress, (ii) an isoelectric process consisting of applying a uniaxial compressive stress rH followed by (iii) an electric de-poling process under constant compressive stress, and finally (i...

This paper reports improved screen-printed piezoelectric composites that can be printed on fabrics or flexible substrates. The materials are flexible and are processed at lower temperature (130°C). One main PZT particle size (2μm) was mixed separately with smaller piezoelectric particles (0.1, 0.3 and 0.8μm) with different weight ratios to investigate the piezoelectric property d33. The blended...