Nanotechnology in the context of organic food processing

Nanotechnology, the science of the ultra small, is up-and-coming as the technological platform for the next wave of development and transformation of agri-food systems. It is quickly moving from the laboratory onto supermarket shelves and our kitchen tables (Scrinis and Lyons, 2007). Therefore we investigated in a literature review and a comparison of the findings with the EU regulation of organic farming to what degree nanotechnology can be applied in organic food production. The regulations do not restrict the use of nanotechnology in general. Because little is known about the impact on environment and human health, precaution should be taken when it comes to applying this technology in organic food production

Generalizing Negative Imaginary Systems Theory to Include Free Body Dynamics: Control of Highly Resonant Structures with Free Body Motion

Negative imaginary (NI) systems play an important role in the robust control of highly resonant flexible structures. In this paper, a generalized NI system framework is presented. A new NI system definition is given, which allows for flexible structure systems with colocated force actuators and position sensors, and with free body motion. This definition extends the existing definitions of NI systems. Also, necessary and sufficient conditions are provided for the stability of positive feedback control systems where the plant is NI according to the new definition and the controller is strictly negative imaginary. The stability conditions in this paper are given purely in terms of properties of the plant and controller transfer function matrices, although the proofs rely on state space techniques. Furthermore, the stability conditions given are independent of the plant and controller system order. As an application of these results, a case study involving the control of a flexible robotic arm with a piezo-electric actuator and sensor is presented

Connections between integral quadratic constraints and dissipativity

We show that a recent dissipativity approach to feedback stability analysis of potentially open-loop unstable systems, which encompasses the classical soft integral quadratic constraint (IQC) theorem, may be recovered by hard IQC theory. The latter is known to be subsumable by the more general soft IQC theory endowed with homotopies that are continuous in the gap topology. Additionally, we demonstrate how the aforementioned classical soft IQC theorem, initially introduced for the analysis of a feedback interconnection of a nonlinear component anda linear system, may be recast to analyse the stability of a feedback interconnection of two nonlinear systems. This generates a frequency-dependent (Q(ω), S(ω), R(ω))-dissipativity resul

Converse negative imaginary theorems

Converse negative imaginary theorems for linear time-invariant systems are derived. In particular, we provide necessary and sufficient conditions for a feedback system to be robustly stable against various types of negative imaginary (NI) uncertainty. Both marginally stable and exponentially stable uncertain NI systems with restrictions on their static or instantaneous gains are considered. It is shown that robust stability against the former class entails the well-known strict NI property, whereas the latter class entails a new type of output strict NI property that is hitherto unexplored. We also establish a non-existence result that no stable system can robustly stabilise all marginally stable NI uncertainty, thereby showing that the uncertainty class of NI systems is too large as far as robust feedback stability is concerned, thus justifying the consideration of subclasses of NI systems with constrained static or instantaneous gains.Comment: This paper has been submitted for possible publication at Automatic