One-dimensional polyelectrolyte/polymeric semiconductor core/shell structure : sulfonated poly(arylene ether ketone)/polyaniline nanofibers for organic field-effect transistors

A polyelectrolyte/polymeric semiconductor core/shell structure is developed for organic field-effect transistors (OFETs) based on sulfonated poly(arylene ether ketone)/polyaniline core/shell nanofibers via electrospinning and solution-phase selective polymerization. The polyelectrolyte does not work as a gate dielectric, but can provide an internal modulation from the nanointerface of the 1D core/shell nanostructure. The transistor devices display very high mobilities.

Au-doped polyacrylonitrile-polyaniline core-shell electrospun nanofibers having high field-effect mobilities

Au-doped polyacrylonitrile–polyaniline core–shell nanofibers are fabricated via electrospinning and subsequent gas-phase polymerization, providing a very high field-effect mobility of up to 11.6 cm² V⁻¹ s⁻¹. This method is also suitable for other conducting polymers and may eventually lead to a new and simplified fabrication of high-performance polymer organic field-effect transistors.

Robust, electro-conductive, self-healing superamphiphobic fabric prepared by one-step vapour-phase polymerisation of poly(3,4-ethylenedioxythiophene) in the presence of fluorinated decyl polyhedral oligomeric silsesquioxane and fluorinated alkyl silane

A robust, electrically conductive, superamphiphobic fabric was prepared by vapour-phase polymerisation of 3,4-ethylenedioxythiophene (EDOT) on fabric in the presence of fluorinated decyl polyhedral oligomeric silsesquioxane (FD-POSS) and a fluorinated alkyl silane (FAS). The coated fabric had contact angles of 169° and 156° respectively to water and hexadecane, and a surface resistance in the range of 0.8–1.2 kΩ o⁻¹ . The incorporation of FD-POSS and FAS into the PEDOT layer showed a very small influence on the conductivity but improved the washing and abrasion stability considerably. The coated fabric can withstand at least 500 cycles of standard laundry and 10000 cycles of abrasion without apparently changing the superamphiphobicity, while the conductivity only had a small reduction after the washing and abrasion. More interestingly, the coating had a self-healing ability to auto-repair from chemical damages to restore the liquid repellency.

Phase behaviour and properties of microemulsions and lyotropic liquid crystals

This research study has developed new ways to control bulk properties of self-assembled microemulsions and lyotropic liquid crystals (LLCs) by manipulations of their corresponding precursor phase behaviour. Investigation into relating phase behaviour with the morphology, porosity, thermal stability, rheological property, and photoresponse of these assemblies has been carried out.

Phase and crystal orientation study of a TRansformation Induced Plasticity steel subjected to cyclic load induced fatigue

An electron backscatter diffraction (EBSD) study of the microstructure of TRIP steel during fatigue failure. Phase and crystal orientation study of a TRIP steel subjected to cyclic load induced fatigue. The relative fractions of austenite, ferrite and martensite are quantified within the strain field of a fatigue crack tip. This data is a subset of data supporting a wider study of the fatigue properties of multiphase steels used in the automotive industry. The different microstructural phases present in these steels can influence the strain life and cyclic stabilized strength of the material due to the way in which these phases accommodate the applied cyclic strain. Fully reversed strain-controlled low-cycle fatigue tests have been used to determine the mechanical fatigue performance of a dual-phase (DP) 590 and transformation induced plasticity (TRIP) 780 steel, with transmission electron microscopy (TEM) and scanning electron microscopy (SEM-EBSD) used to examine the deformed microstructures .

Voltage stability analysis with optimum size and location based synchronous machine DG

Power loss of a distribution system can be reduced significantly by using optimum size and location of distributed generation (DG). Proper allocation of DG with appropriate size maximizes overall system efficiency. Moreover it improves the reliability and voltage profile of the distribution system. In this paper, IEEE 123 node test feeder has been considered to determine the optimum size and location of a synchronous machine based DG for loss reduction of the system. This paper also investigates the steady-state and dynamic voltage profile of that three phase unbalance distribution network in presence of DG with optimum size. This analysis shows that optimum size of DG at proper location minimizes the power loss as well as improves the dynamic voltage profile of the distribution system.

Space vector modulation based fast speed response field-orientation control of induction motor drive with adaptive neural integrator

This paper presents a novel fast speed response control strategy for the poly-phase induction motor drive system based on flux angle. The control scheme is derived in rotor field coordinates and employs the estimation of the rotor flux and its position. An adaptive notch filter is proposed to eliminate the dc component of the integration of signals used for the rotor flux estimation. To improve the performance of the rotor flux estimator, derivative term of the back emf is incorporated in the system. The voltage components in the synchronous reference frame are generated in the controllers which are transformed to stationary reference frame for driving the motor. Space vector modulation technique is used here. Simulation of the drive system was carried out and the results were compared with those obtained for a system that produces the above mentioned voltage components using the conventional PI controller. It is observed that the proposed control methodology provides faster response than the conventional PI controller incorporated system.

Multi-phase microstructure design of a novel high strength TRIP steel through experimental methodology

The multi-phase structure of a novel low-alloy transformation induced plasticity (TRIP) steel was designed through experimental analysis. The evolutions of both microstructure and mechanical properties during the two-stage heat treatment were analyzed. The phase transformations during the intercritical annealing and the isothermal bainitic transformation were investigated by means of dilatometry. It was shown that two types of C diffusion were detected during intercritical annealing and a complex microstructure was formed after heat treatment. The processing parameters were selected in such a way to obtain microstructures with systematically different volume fractions of ferrite, bainite and retained austenite. The volume fractions of ferrite and retained austenite were found to be two main factors controlling the ductility. Furthermore, a high volume fraction of C-rich retained austenite, which was stabilized at room temperature, was the origin of a TRIP effect. The resulting material demonstrates a significant improvement in the ultimate tensile strength (1077. MPa) with good uniform elongation (22.5%), as compared to conventional TRIP steels. © 2014 Elsevier B.V.

A comprehensive analytical subdomain model and its field solutions for surface-mounted permanent magnet machines

This paper presents a comprehensive analytical subdomain model together with its field solutions for predicting the magnetic field distributions in surface-mounted permanent magnet (PM) machines. The tooth tips and slotting effects during open-circuit, armature reaction, and on-load conditions are considered when deriving the model and developing its solutions. The model derivations and field solutions are extended from a previous model, and can be applied to PM machines with any combinations of slot and pole numbers and any magnetization patterns in the magnets. This model is initially formulated according to Laplace's and Poisson's equations in 2-D polar coordinates by the separation of variables technique in four subdomains, such as magnet, airgap, winding slots, and slot-openings. The field solution of each subdomain is obtained applying the appropriate boundary conditions and interface conditions between every two subdomains, respectively, which can precisely account for the mutual influence between slots. Finite element analysis (FEA) is later deployed to validate the analytical results in a surface-mounted PM machine that has nonoverlapping winding arrangement. For validation purposes, PM machines having 3-slot/2-pole with parallel magnetization and 12-slot/10-pole with either parallel or radial magnetizations are used for comparisons. Computation of global quantities for the motor which include the phase back-EMF and cogging torque is also included. The results indicate that the proposed analytical model can accurately predict the magnetic field distributions in each subdomain and the motor's global quantities, which are in good agreement with those obtained from the FEA.

Enhancing thermal stability and mechanical properties of lyotropic liquid crystals through incorporation of a polymerizable surfactant.

We present a facile method to prepare thermally stable and mechanically robust crosslinked lyotropic liquid crystals (LLCs) through incorporation of a polymerizable amphiphile into a binary LLC system comprising commercially available surfactant Brij 97 and water. Thermal stability and mechanical properties of the polymerized LLCs were significantly enhanced after polymerization of the incorporated polymerizable surfactant. The effect of incorporating a polymerizable amphiphile on the phase behavior of the LLC system was studied in detail. In situ photo-rheology was used to monitor the change in the mechanical properties of the LLCs, namely the storage modulus, loss modulus, and viscosity, upon polymerization. The retention of the LLC nanostructures was evaluated by small angle X-ray scattering (SAXS). The ability to control the thermal stability and mechanical strength of LLCs simply by adding a polymerizable amphiphile, without tedious organic synthesis or harsh polymerization conditions, could prove highly advantageous in the preparation of robust nanomaterials with well-defined periodic structures.

Novel reversible and switchable electrolytes based on magneto-rheology

Replacing organic liquid electrolytes with solid electrolytes has led to a new perspective on batteries, enabling high-energy battery chemistry with intrinsically safe cell designs. However, most solid/gel electrolytes are easily deformed; under extreme deformation, leakage and/or short-circuiting can occur. Here, we report a novel magneto-rheological electrolyte (MR electrolyte) that responds to changes in an external magnetic field; the electrolyte exhibits low viscosity in the absence of a magnetic field and increased viscosity or a solid-like phase in the presence of a magnetic field. This change from a liquid to solid does not significantly change the conductivity of the MR electrolyte. This work introduces a new class of magnetically sensitive solid electrolytes that can enhance impact resistance and prevent leakage from electronic devices through reversible active switching of their mechanical properties.

A comparative study of different power system stabilizers for dynamic stability analysis

Power system stabilizers (PSSs) are extensively used to ensure the dynamic stability of power systems through the modulation of excitation signals supplied to synchronous generators. This paper presents a comparative study of two different PSSs: STAB1 and IEEEST. The stabilizers are designed for the linearized model of a single machine infinite bus (SMIB) system with different loads. Both time-and frequency-domain simulations are carried out to investigate the performance of these stabilizers. For all PSSs, the time-domain simulations are performed by applying a three-phase short-circuit fault at the terminal of the synchronous generator. These simulation results are compared against the open-loop characteristics of the SMIB system where no PSS is implemented. Simulation results demonstrate that the speed-fed PSS provides more damping as compared to frequency- and power-fed stabilizers.

International civil society actors in Genetically Modificied Organisms as a field of struggle: a neo-gramscian study in Brazil and the United Kingdom

Since the international financial and food crisis that started in 2008, strong emphasis has been made on the importance of Genetically Modified Organisms (GMOs) (or “transgenics”) under the claim that they could contribute to increase food productivity at a global level, as the world population is predicted to reach 9.1 billion in the year 2050 and food demand is predicted to increase by as much as 50% by 2030. GMOs are now at the forefront of the debates and struggles of different actors. Within civil society actors, it is possible to observe multiple, and sometime, conflicting roles. The role of international social movements and international NGOs in the GMO field of struggle is increasingly relevant. However, while many of these international civil society actors oppose this type of technological developments (alleging, for instance, environmental, health and even social harms), others have been reportedly cooperating with multinational corporations, retailers, and the biotechnology industry to promote GMOs. In this thesis research, I focus on analysing the role of “international civil society” in the GMO field of struggle by asking: “what are the organizing strategies of international civil society actors, such as NGOs and social movements, in GMO governance as a field of struggle?” To do so, I adopt a neo-Gramscian discourse approach based on the studies of Laclau and Mouffe. This theoretical approach affirms that in a particular hegemonic regime there are contingent alliances and forces that overpass the spheres of the state and the economy, while civil society actors can be seen as a “glue” to the way hegemony functions. Civil society is then the site where hegemony is consented, reproduced, sustained, channelled, but also where counter-hegemonic and emancipatory forces can emerge. Considering the importance of civil society actors in the construction of hegemony, I also discuss some important theories around them. The research combines, on the one hand, 36 in-depth interviews with a range of key civil society actors and scientists representing the GMO field of struggle in Brazil (19) and the UK (17), and, on the other hand, direct observations of two events: Rio+20 in Rio de Janeiro in 2012, and the first March Against Monsanto in London in 2013. A brief overview of the GMO field of struggle, from its beginning and especially focusing in the 1990s when the process of hegemonic formation became clearer, serves as the basis to map who are the main actors in this field, how resource mobilization works, how political opportunities (“historical contingencies”) are discovered and exploited, which are the main discourses (“science” and “sustainability” - articulated by “biodiversity preservation”, “food security” and “ecological agriculture”) articulated among the actors to construct a collective identity in order to attract new potential allies around “GMOs” (“nodal point”), and which are the institutions and international regulations within these processes that enable hegemony to emerge in meaningful and durable hegemonic links. This mapping indicates that that the main strategies applied by the international civil society actors are influenced by two central historical contingencies in the GMO field of struggle: 1) First Multi-stakeholder Historical Contingency; and 2) “Supposed” Hegemony Stability. These two types of historical contingency in the GMO field of struggle encompass deeper hegemonic articulations and, because of that, they induce international civil society actors to rethink the way they articulate and position themselves within the field. Therefore, depending on one of those moments, they will apply one specific strategy of discourse articulation, such as: introducing a new discourse in hegemony articulation to capture the attention of the public and of institutions; endorsing new plural demands; increasing collective visibility; facilitating material articulations; sharing a common enemy identity; or spreading new ideological elements among the actors in the field of struggle.

Quantification of polyphenols with potential antioxidant properties in wines using reverse phase HPLC

A RP-HPLC method with photodiode array detection (DAD) was developed to separate, identify and quantify simultaneously the most representative phenolic compounds present in Madeira and Canary Islands wines. The optimized chromatographic method was carefully validated in terms of linearity, precision, accuracy and sensitivity. A high repeatability and a good stability of phenolics retention times (a3%) were obtained, as well as relative peak area. Also high recoveries were achieved, over 80.3%. Polyphenols calibration curves showed a good linearity (r2 A0.994) within test ranges. Detection limits ranged between 0.03 and 11.5 lg/mL for the different polyphenols. A good repeatability was obtained, with intra-day variations less than 7.9%. The described method was successfully applied to quantify several polyphenols in 26 samples of different kinds of wine (red, ros and white wines) from Madeira and Canary Islands. Gallic acid was by far the most predominant acid. It represents more than 65% of all phenolics, followed by p-coumaric and caffeic acids. The major flavonoid found in Madeira wines was trans-resveratrol. In some wines, (–)-epicatechin was also found in highest amount. Canary wines were shown to be rich in gallic, caffeic and p-coumaric acids and quercetin.

Local Field Potentials in the Gustatory Cortex Carry Taste Information

It has been recently shownthat localfield potentials (LFPs)fromthe auditory and visual cortices carry information about sensory stimuli, but whether this is a universal property of sensory cortices remains to be determined. Moreover, little is known about the temporal dynamics of sensory information contained in LFPs following stimulus onset. Here we investigated the time course of the amount of stimulus information in LFPs and spikes from the gustatory cortex of awake rats subjected to tastants and water delivery on the tongue. We found that the phase and amplitude of multiple LFP frequencies carry information about stimuli, which have specific time courses after stimulus delivery. The information carried by LFP phase and amplitude was independent within frequency bands, since the joint information exhibited neither synergy nor redundancy. Tastant information in LFPs was also independent and had a different time course from the information carried by spikes. These findings support the hypothesis that the brain uses different frequency channels to dynamically code for multiple features of a stimulus.