Part 3. MOO methods for multidisciplinary design using parallel evolutionary algorithms, game theory and hierarchical topology. (Part 3.) Practical application to the design and optimisation of UAV systems

These lecture notes highlight some of the recent applications of multi-objective and multidisciplinary design optimisation in aeronautical design using the framework and methodology described in References 8, 23, 24 and in Part 1 and 2 of the notes. A summary of the methodology is described and the treatment of uncertainties in flight conditions parameters by the HAPEAs software and game strategies is introduced. Several test cases dealing with detailed design and computed with the software are presented and results discussed in section 4 of these notes.

Structure, bonding state and in-vitro study of Ca–P–Ti film deposited on Ti6Al4V by RF magnetron sputtering

Experimental investigation of functionally graded calcium phosphate-based bio-active films on Ti-6A1-4V orthopaedic alloy prepared in an RF magnetron sputtering plasma reactor is reported. The technique involves concurrent sputtering of Hydroxyapatite (HA) and Ti targets, which results in remarkably enhanced adhesion of the film to the substrate and stability of the interface. The films have been characterized using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The XPS data show that the films are composed of O, Ca, P and Ti, and reveal the formation of O=P groups and hybridization of O-Ca-P. The XRD pattern shows that the Ca-P thin films are of crystalline calcium oxide phosphate (4CaO·P2O5) with preferred orientation varying with processing parameters. High-resolution optical emission spectra show that the emission of CaO is dominant. The CaO, PO and CaPO species are strongly influenced by deposition conditions. The introduction of Ti element during deposition provides a stable interface between bio-inert substrates Ti-6A1-4V and bioactive HA coating. In-vitro cell culturing tests suggest excellent biocompatibility of the Ca-P-Ti films.

E and H regimes of plasma enhanced chemical vapor deposition of diamond-like carbon film in low frequency inductively coupled plasma reactor

This paper reports on the efficient deposition of hydrogenated diamond-like carbon (DLC) film in a plasma reactor that features both the capacitively and inductively coupled operation regimes. The hydrogenated DLC films have been prepared on silicon wafers using a low-frequency (500 kHz) inductively coupled plasma (ICP) chemical vapor deposition (CVD) system. At low RF powers, the system operates as an asymmetric capacitively coupled plasma source, and the film deposition process is undertaken in the electrostatic (E) discharge regime. Above the mode transition threshold, the high-density inductively coupled plasma is produced in the electromagnetic (H) discharge regime. It has been shown that the deposition rate and hardness of the DLC film are much higher in the H-mode deposition regime. For a 2.66-Pa H-mode CH4 + Ar gas mixture discharge, the deposited DLC film exhibits a mechanical hardness of 18 GPa, Young's modulus of 170 GPa, and compressive stress of 1.3 GPa.

Numerical simulation of nanoparticle-generating electronegative plasmas in the PECVD of nanostructured silicon film

The results of numerical simulation of the equilibrium parameters of a low pressure nanopowder-generating discharge in silane for the plasma enhanced chemical vapor deposition (PECVD) of nanostructured silicon-based films are presented. It is shown that a low electron temperature and a low density of negative SiH3 - ions are favorable for the PECVD process. This opens a possibility to predict the main parameters of the reactive plasma and plasma-nucleated nanoparticles, and hence, to control the quality of silicon nanofilms.

Two-channel waveguide modulator based on surface wave propagating in a semiconductor-metal thin-film structure

The results of theoretical investigations of two-channel waveguide modulator based on Surface Wave (SW) propagation are presented. The structure studied consists of two n-type semiconductor waveguide channels separated from each other by a dielectric gap and coated by a metal. The SW propagates at the semiconductor-metal interface across an external magnetic field which is parallel to the interface. An external dc voltage is applied to the metal surface of one channel to provide a small phase shift between two propagating modes. In a coupled mode approximation, two possible regimes of operation of the structure, namely as a directional coupler and as an electro-optical modulator, are considered. Our results suggest new applications in millimeter and submillimeter wave solid-state electronics and integrated optics.

Information Experience : Approaches to Theory and Practice

"The German word for experience - Erlebnis - the experience of the life, to live through something - underpins this book: making visible scholarly opportunities for richer and deeper contextualizations and examinations of the lived-world experiences of people in everyday contexts as they be, do and become." (Ross Todd, Preface). Information experience is a burgeoning area of research and still unfolding as an explicit research and practice theme. This book is therefore very timely as it distils the reflections of researchers and practitioners from various disciplines, with interests ranging across information, knowledge, user experience, design and education. They cast a fresh analytical eye on information experience, whilst approaching the idea from diverse perspectives. Information Experience brings together current thinking about the idea of information experience to help form discourse around it and establish a conceptual foundation for taking the idea forward. It therefore "provides a number of theoretical lenses for examining people's information worlds in more holistic and dynamic ways." (Todd, Preface)

Thermal effect of plasmon oscillations on the tunnel current in gold nanoisland thin film at low laser intensity

The effect of plasmon oscillations on the DC tunnel current in a gold nanoisland thin film (GNITF) is investigated using low intensity P~1W/cm2 continuous wave lasers. While DC voltages (1–150 V) were applied to the GNITF, it was irradiated with lasers at different wavelengths (k¼473, 532, and 633 nm). Because of plasmon oscillations, the tunnel current increased. It is found that the tunnel current enhancement is mainly due to the thermal effect of plasmon oscillations rather than other plasmonic effects. The results are highly relevant to applications of plasmonic effects in opto-electronic devices.

Postmodern Theory and the Choreography of Michael Clark

This study addresses two interrelated questions: Can postmodern ‘theory’ illuminate an understanding of Michael Clark’s work? and, a sub-question, In which ways, if at all, does Clark’s work demonstrate a postmodern sensibility? Chapter one, the introduction to this study, provides a ‘portrait’ of postmodernism, that is, it addresses the question What is postmodernism? Chapter two is a biography of Michael Clark. The seminal sections to this study, however, are chapters three and four. Here the author blends a discussion of a) subject matter, treatment and meanings in Clark’s choreography, b) journalistic criticisms of those features of his work, and c) postmodern theory. The outcome of these chapters is to demonstrate that Clark’s works do indeed require re-interpretation and re-evaluation, and to illustrate how these factors might be achieved.

An acoustically enhanced gold film Raman sensor on a lithium niobate substrate

The surface enhanced Raman scattering effect has shown immense potential for detecting trace amounts of explosive vapor molecules. To date, efforts to produce a commercially available, reliable SERS sensor have been impeded by an inability to separate the electromagnetic enhancement produced by the metallic nanostructure from other signal enhancing effects. Here, we show a new Raman sensor that uses surface acoustic waves (SAWs) to produce controllable surface structures on gold films deposited on LiNbO3 substrates that modulate the Raman signal of a target compound (thiophenol) adsorbed on the films. We demonstrate that this sensor can dynamically control the Raman signal simply by changing the SAW’s amplitude, allowing the Raman signal enhancement factor to be directly measured with no variation in the concentration of the target compound. The physically adsorbed molecules can be removed from the sensor without physical cleaning or damage, making it possible to reuse it for real-time Raman detection.

Charge transport and density of trap states in balanced high mobility ambipolar organic thin-film transistors

We report on charge transport and density of trap states (trap DOS) in ambipolar diketopyrrolopyrrole-benzothiadiazole copolymer thin-film transistors. This semiconductor possesses high electron and hole field-effect mobilities of up to 0.6 cm 2/V-s. Temperature and gate-bias dependent field-effect mobility measurements are employed to extract the activation energies and trap DOS to understand its unique high mobility balanced ambipolar charge transport properties. The symmetry between the electron and hole transport characteristics, parameters and activation energies is remarkable. We believe that our work is the first charge transport study of an ambipolar organic/polymer based field-effect transistor with room temperature mobility higher than 0.1 cm 2/V-s in both electrons and holes.

High mobility top-gate and dual-gate polymer thin-film transistors based on diketopyrrolopyrrole-naphthalene copolymer

In this letter, the performance characteristics of top-gate and dual-gate thin-film transistors (TFTs) with active semiconductor layers consisting of diketopyrrolopyrrole-naphthalene copolymer are described. Optimized top-gate TFTs possess mobilities of up to 1 cm 2 /V s with low contact resistance and reduced hysteresis in air. Dual-gate devices possess higher drive currents as well as improved subthreshold and above threshold characteristics compared to single-gate devices. We also describe the reasons that dual-gate devices result in improved performance. The good stability of this polymer combined with their promising electrical properties make this material a very promising semiconductor for printable electronics.

Charge-carrier velocity distributions in high-mobility polymer dual-gate thin-film transistors

We report charge-carrier velocity distributions in high-mobility polymer thin-film transistors (PTFTs) employing a dual-gate configuration. Our time-domain measurements of dual-gate PTFTs indicate higher effective mobility as well as fewer low-velocity carriers than in single-gate operation. Such nonquasi-static (NQS) measurements support and clarify the previously reported results of improved device performance in dual-gate devices by various groups. We believe that this letter demonstrates the utility of NQS measurements in studying charge-carrier transport in dual-gate thin-film transistors.

Charge transport study of high mobility polymer thin-film transistors based on thiophene substituted diketopyrrolopyrrole copolymers

In this paper, we report on the device physics and charge transport characteristics of high-mobility dual-gated polymer thin-film transistors with active semiconductor layers consisting of thiophene flanked DPP with thienylene-vinylene-thienylene (PDPP-TVT) alternating copolymers. Room temperature mobilities in these devices are high and can exceed 2 cm2 V-1 s-1. Steady-state and non-quasi-static measurements have been performed to extract key transport parameters and velocity distributions of charge carriers in this copolymer. Charge transport in this polymer semiconductor can be explained using a Multiple-Trap-and-Release or Monroe-type model. We also compare the activation energy vs. field-effect mobility in a few important polymer semiconductors to gain a better understanding of transport of DPP systems and make appropriate comparisons.

Synthesis, thin-film morphology, and comparative study of bulk and bilayer heterojunction organic photovoltaic devices using soluble diketopyrrolopyrrole molecules

Diketopyrrolopyrrole (DPP)-based organic semiconductors EH-DPP-TFP and EH-DPP-TFPV with branched ethyl-hexyl solubilizing alkyl chains and end capped with trifluoromethyl phenyl groups were designed and synthesized via Suzuki coupling. These compounds show intense absorptions up to 700 nm, and thin film-forming characteristics that sensitively depend on the solvent and coating conditions. Both materials have been used as electron donors in bulk heterojunction and bilayer organic photovoltaic (OPV) devices with fullerenes as acceptors and their performance has been studied in detail. The best power conversion efficiency of 3.3% under AM1.5G illumination (100 mW cm -2) was achieved for bilayer solar cells when EH-DPP-TFPV was used with C 60, after a thermal annealing step to induce dye aggregation and interdiffusion of C 60 with the donor material. To date, this is one of the highest efficiencies reported for simple bilayer OPV devices.

A high mobility P-type DPP-thieno[3,2-b]thiophene copolymer for organic thin-film transistors

A copolymer comprising 1,4-diketopyrrolo[3,4-c]pyrrole (DPP) and thieno[3,2-b]thiophene moieties, PDBT-co-TT, shows high hole mobility of up to 0.94 cm2 V-1 s-1 in organic thin-film transistors. The strong intermolecular interactions originated from π-π stacking and donor-acceptor interaction lead to the formation of interconnected polymer networks having an ordered lamellar structure, which have established highly efficient pathways for charge carrier transport.