Polymer-nanoparticle composites composed of PEDOT:PSS and nanoparticles of Ag synthesised by laser ablation

Laser ablation of a solid target material in a liquid environment provides with an easy, straightforward and environmentally friendly method for nanoparticles synthesis as well as with the unique possibility of directly controlling the type of the nanoparticles surface ligands through the liquid choice. In this paper, laser ablation (10.4 ps, 1064 nm and 50 kHz) of a bulk silver target in deionized water, was carried out for nanoparticles synthesis. The synthesised nanoparticles are either pure Ag or A₂O₃ or a mixture of the two materials. Their size distribution follows log-normal function with a statistical median diameter of ≈5 nm. The nanoparticles colloidal solutions were directly mixed after synthesis, with the polymer solution poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) for the formation of polymer-nanoparticles nanocomposite. The nanoparticles readily form bonds with the sulphur atom of PEDOT which results in their uniform distribution within the polymer matrix as well as in a replacement by the nanoparticles of the PSS⁻ as the counteranions to the PEDOT⁺. These effects result in the reduction of the effective insulation of the polymer blend particles by the insulating PSS and furthermore in the electrical conductivity of the nanocomposite becoming higher (by ∼1.5 times) as compared with that of the pure polymer.     

Thiol Functionalised Supports for Controlled Metal Nanoparticle Formation for Improved C–C Coupling

The myriad applications of metal nanoparticle systems have individual demands on their size, shape and electronic states, demanding novel synthetic methods to optimise these properties. Herein we report our method of exploiting strong thiol-Pd binding as a precursor for forming small, uniform Pd nanoparticles on activation. We validate our approach with a range of characterisation techniques and contrast our design strategy with an analogous wetness impregnation method, showing the drastic improvements for catalytic C−C coupling. The presence of the thiol groups offers greater control over nanoparticle formation, particularly temperature resolution on activation, potentially allowing more targeted nanoparticle formation procedures.     

Computationally attractive real Gabor transforms

We present a Gabor transform for real, discrete signals and present a computationally attractive method for computing the transform. For the critically sampled case, we derive a biorthogonal function which is very localized in the time domain. Therefore, truncation of this biorthogonal function allows us to compute approximate expansion coefficients with significantly reduced computational requirements. Further, truncation does not degrade the numerical stability of the transform. We present a tight upper bound on the reconstruction error incurred due to use of a truncated biorthogonal function and summarize computational savings. For example, the expense of transforming a length 2048 signal using length 16 blocks is reduced by a factor of 26 over similar FFT-based methods with at most 0.04% squared error in the reconstruction     

Robotic preparation of metal samples for analysis by plasma emission spectrometry

Summary A method utilizing a laboratory robotic system to automate sample preparation for the chemical analysis of metals was developed. Anticipated elemental concentration values for samples are entered into the robotic system, and the system determines the needed sample weights and calibration solution concentrations. The robot then weighs, dissolves, and dilutes the samples and prepares calibration solutions prior to multi-elemental analyses by inductively-coupled plasma — atomic-emission spectrometry. Zinc-base alloy standard reference materials were used to evaluate this method. For a batch of ten samples, operator times compared with a similar manual method were reduced by about 5-fold. Precision and accuracy data for samples prepared by robotic and manual methods were equivalent.

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Automatische Probenvorbereitung für die Analyse durch Plasma-Emissions-Spektrometrie mit Hilfe eines Laborroboters

     

A test of the core solution in finite strategy non-sidepayment games

This paper reports a test of the core solution in cooperative non-sidepayment games where players have finite strategy sets. Two laboratory experiments were conducted with three-person and four-person games; in both experiments, the core solution was tested competitively against the von Neumann-Morgenstern stable set and the imputation set. Predictions from these solution concepts were computed under parameters of α-effectiveness and strict preference. Results show that the frequency of outcomes falling in core is substantially higher than that observed in previous experiments (most of which involve sidepayment games). In addition, goodness-of-fit tests show that the core solution predicts the observed outcomes more accurately than do the stable set or the imputation set.     

Building Upon the Experimental Design in Media Violence Research: The Importance of Including Receiver Interpretations

The authors argue that the inclusion of viewer interpretation variables in experimental design and analysis procedures can greatly increase the methodology's ability to explain variance. The experiment primarily focused attention on the between-group differences, while an analysis of how individual participants interpret the cues in the stimulus material focused attention on the within-group differences. We demonstrated such an analysis in this study in which 99 participants were exposed to 1 of 3 treatment conditions (high violence, mid violence, and low violence) and found significant differences across treatment groups. However, the treatment differences accounted for only about 7% of the variance in judgments of the degree of violence, whereas a set of interpretive variables accounted for more than 48%.     

Reconstruction of through-surface underwater imagery

We present a technique for rectifying distorted imagery collected by an upward-looking, submerged camera for the purpose of reconstructing the above-surface scene. Radial surface slope is deduced near extinction boundaries separating regions of transmission and internal reflection. The radial slope measurements are fit to an estimate of the distorting surface, which is recursively improved so as to minimize the quadratic measurement error. The surface is assumed to obey linear wave dynamics. After surface estimation, the above-surface scene is reconstructed by inverse ray tracing. Results of testing the wave estimation and inverse-ray tracing algorithms against simulated underwater data are presented.     

The excess energy approach to the impact testing of plastics

This paper evaluates the excess energy approach to impact testing of plastic samples. This approach assumes that providing the impact energy is excessive, the rate of strain during a test may be assumed to be constant. This allows a direct transformation of time to displacement during a test and consequently to a simplification of the integration procedure. The force-time and force-displacement responses of samples to impact have been measured simultaneously using an instrumented falling weight impact machine. It is concluded that the excess energy approach is acceptable providing the available impact energy exceeds the impact strength of the sample by a factor of ten.