Explicit improved vertex control for uncertain,time‐varying linear discrete‐time systems with state and control constraints

A technique is presented to compute an explicit state feedback solution to the regulation problem for uncertain and/or time‐varying linear discrete‐time systems with state and control constraints. A piecewise affine control law is provided that not only guarantees recursive feasibility and robust asymptotic stability but is also optimal for a region of the state space containing the origin. Copyright © 2015 John Wiley & Sons, Ltd.     

The synthesis of MMA-S copolymer starting from PMMA and elemental sulfur

Summary The synthesis of methylmethacrylat (MMA) — sulfur copolymer has been completed by starting from a mixture of Polymethylmethacrylat (PMMA) temperature (360°C) by using a specially designed reaction vessel. The formation of copolymer is spontaneous and is due to the presence of active species (free biradical of MMA and S) generated through the decomposition of PMMA and polysulfur under extreme conditions.The resulted copolymer has been characterized by using elemental analysis, IR, NMR and MS spectroscopy.     

Receding horizon flight control for trajectory tracking of autonomous aerial vehicles

This paper addresses the implementation of a predictive control strategy for Unmanned Air Vehicles in the presence of bounded disturbances. The goal is to prove the feasibility of such a real-time optimization-based control design and to demonstrate its tracking capabilities for the nonlinear dynamics with respect to a reference trajectory which is pre-specified via differential flatness. In order to benefit from the computational advantages of the linear predictive control formulations, an off-line linearization strategy of the nonlinear model of the vehicle along the flat trajectory is employed. The proposed method exhibits effective performance validated through software-in-the-loop simulations and real flight tests on different Unmanned Aerial Vehicles (UAVs).     

Prospects for analyzing the electronic properties in nanoscale systems by VEELS

Valence electron energy-loss spectroscopy in the scanning transmission electron microscope can provide detailed information on the electronic structure of individual nanostructures. By employing the latest advances in electron optical devices, such as a probe aberration corrector and an electron monochromator, the probe size, spectroscopic resolution, probe current and primary electron energy can be varied over a large range. This flexibility is particularly important for nanostructures where each of these variables needs to be carefully counterbalanced in order to collect spectroscopic data without altering the integrity of the sample. Here the implementation of valence electron energy-loss spectroscopy to the study of nanostructures is discussed, with particular mention to the theoretical understanding of each of the contributions to the overall spectrum.     

Synthesis and characterization of side-chain oxazoline–methyl methacrylate copolymers bearing azo-dye

We synthesized new polymeric structures by attaching a side-chain azo-moiety on poly(oxazoline) and poly(oxazoline-co-methyl methacrylate)s. For the polymer analogous transformation, we took advantage of the highly effective ring-opening addition of carboxyl group to the oxazoline cycle. The comonomers feed ratio allowed us to control the composition of the products while the kinetic treatment, employing an integral method, revealed a statistical copolymerization tendency of 2-isopropenyl-2-oxazoline with methyl methacrylate in acetonitrile at 70 °C. The elemental analysis and ¹H NMR spectroscopy provided almost identical composition data for both the substrates and the side-chain copolymers. The UV spectroscopy sustained the quantitative addition of 4-(4-hydroxy-3,5-dimethylphenylazo)benzoic acid to the oxazoline rings. Both the unmodified copolymers and the coloured ones exhibited good thermal stabilities, up to 371 °C and 302 °C, respectively. The glass transition temperatures ranged from 141.5 to 177.5 °C and from 153.8 to 200.9 °C for the substrates and for the modified copolymers, respectively. Preliminary investigations showed fluorescence activity for all copolymers bearing azo-moieties.     

Transversal Flux Scanning Induction Heating of Magnetic Nonlinear Steel Sheets With Temperature Dependent Properties

This paper deals with finite element study of the scanning induction heating of the magnetic steel sheets in transversal flux devices,taking into account the magnetic nonlinearity and the dependence on temperature of steel properties.The decrease of the non-uniformity of the transversal profile of sheet heating as effect of the magnetic or electromagnetic screening of the sheet lateral sides was proved.     

New cascades for thermo-chemical refrigeration

A diagrammatical approach for the design of new thermo-chemical cascades for heat management purposes is proposed. The two key elements of this approach are: a method to automatically generate system architectures and a general approach to selecting appropriate materials. It is based on establishing an explicit correspondence between the exergy balance around a thermo chemical system, the properties of the reactants and the operational system parameters. A new auto thermal configuration involving two thermally coupled single effect processes is proposed and suitable materials for its implementation are identified. The method is illustrated for the design of an experimental installation for the testing of a thermo-chemical refrigeration system operated at distance from a heat source.