Optimized Discrete Control Law for Quadrotor Stabilization: Experimental Results

This paper deals with the real-time stabilization of a Quadrotor mini helicopter applying a discrete optimal control. A discrete control strategy is better adapted to be executed in a micro-controller, therefore better results are expected with respect to continuous case. Furthermore, the optimal control law allows to helicopter to save energy and then increase its time of flight. The discrete optimal control law is synthesized considering an infinite horizon together with an exact linearization of the nonlinear dynamics of flying vehicle. At the end of this procedure the optimal control law obtained through an exact linearization is simple and easier to tune compared to the optimal strategy where the exact linearization is not performed. Taking into account the obtained experimental results, the proposed control technique produces an appropriate stabilization of the mini UAV.     

High and low esterification degree pectins decomposition by hydrolysis and modified Maillard reactions for furfural production

In recent years, there has been a great interest in the conversion of lignocellulosic structures to furfural. There are many technologies available for this process. Nonetheless, the present work reports for the first time the use of pectin, a non-lignocellulosic structure, for furfural production. The pectin was extracted from food industry waste derived from cactuses, orange peels and mangoes peels. The extracted pectins were analyzed by infrared spectroscopy (ATR–FTIR) in order to evaluate the degree of esterification (DE). The high DE influences in the hydrolysis reaction in the following stages: (1) hydration, it allows a fast glycosidic bond cleavage in the polysaccharide. (2) Dehydration, an intermediary step in the furfural production from galacturonic acid. The Maillard reaction herein reported not only is used in a novel way to produce furfural but also it has been modified to be performed in acidic conditions to increase the furfural production rate. From the evaluated reactions, it was found that the highest furfural production was obtained with manila mango pectin (82.6 g/L) with a DE of 51.2%. These findings demonstrate that pectins with DE below 75%, the minimum value to be considered for applications in the food and pharmaceutical industries, could be applied for the generation of furfural, a chemical platform for the production of chemicals and biofuels.     

Nanoscale Fabrication of the Ferroelectric Polymer Poly(vinylidene Fluoride with Trifluoroethylene) P(VDF‐TrFE) 75:25 Thin Films by Atomic Force Microscope Nanolithography

Thin films of an organic ferroelectric system, poly(vinylidene fluoride with trifluoroethylene) P(VDF‐TrFE, Kureha Corporation, Tokyo, Japan) 75:25 layers, have been deposited on highly ordered pyrolytic graphite and silicon dioxide by the horizontal Schaefer method of Langmuir–Blodgett techniques. It is possible to “shave” or mechanically displace small regions of the polymer film by using atomic force microscope nanolithography techniques such as nanoshaving, leaving swaths of the surface cut to a depth of 4 nm and 12 nm exposing the substrate. The results of fabricating stripes by nanoshaving two holes close to each other show a limit to the material “stripe” widths of an average of 153.29 nm and 177.67 nm that can be produced. Due to the lack of adhesion between the substrates and the polymer P(VDF‐TrFE) film, smaller “stripes” of P(VDF‐TrFE) cannot be produced, and it can be shown by the sequencing of nanoshaved regions that “stripes” of thin films can be removed. SCANNING 34: 404‐409, 2012. © 2012 Wiley Periodicals, Inc.     

HCI down under: reflecting on a decade of the OzCHI conference

In this study we present a scientometric analysis of the Australian Conference on Human–Computer Interaction (OzCHI) proceedings over the period of a decade (2006–2015). Conference proceedings were manually extracted from the ACM Digital Library and analysed. We observed OzCHI to be a popular conference attracting both submissions and citations. A group of leading researchers dominated the publication count followed by a long list of mid career academics. We observed the themes of Design, Health and Well-being and Education to be growing in importance. We also observed that full papers were cited significantly more than short papers. We conclude with a reflection on our methodology and a proposal of recommendations for the HCI/OzCHI community in Australia.