Influence of the aluminium doping on the antiferromagnetic structure of YBa2Cu3O6+x

The magnetic structure of YBCO with low oxygen content is severely influenced by Aluminium doping. The Al-NMR spectra confirm the position of the non-magnetic Al impurities in the Cu(1) layer with a shift from the regular Cu(1) site in <110> direction. The Cu(1) ions in the Al-O-Cu(1) clusters may be responsible for the transition between the antiferromagnetic AFI and AFII phases in the doped crystals. From the Cu-NMR in pure and Al doped single crystals different spin directions in the AFI and AFII phases have been determined, <100> for the pure YBCO and <110>for the Al doped in the AFII state.     

Assessing the importance of audio/video synchronization for simultaneous translation of video sequences

Lip synchronization is considered a key parameter during interactive communication. In the case of video conferencing and television broadcasting, the differential delay between audio and video should remain below certain thresholds, as recommended by several standardization bodies. However, further research has also shown that these thresholds can be relaxed, depending on the targeted application and use case. In this article, we investigate the influence of lip sync on the ability to perform real-time language interpretation during video conferencing. Furthermore, we are also interested in determining proper lip sync visibility thresholds applicable to this use case. Therefore, we conducted a subjective experiment using expert interpreters, which were required to perform a simultaneous translation, and non-experts. Our results show that significant differences are obtained when conducting subjective experiments with expert interpreters. As interpreters are primarily focused on performing the simultaneous translation, lip sync detectability thresholds are higher compared with existing recommended thresholds. As such, primary focus and the targeted application and use case are important factors to be considered when selecting proper lip sync acceptability thresholds.     

A Study on the Utilization of Magnetite for the Recovery of Platinum Group Metals from Chloride Solution

The recovery of platinum group metals (PGMs) from chloride solution using magnetite was investigated. The adsorption of platinum, palladium, and rhodium in chloride medium onto synthetic magnetite powders were studied at different pH conditions, contact time, sodium chloride concentrations, and initial Pt, Rh, and Pd concentrations. Platinum and palladium uptake by magnetite was at a maximum at pH 6–7, and pH 3–4 for rhodium after 24 h with 0.1 mol/dm³ sodium chloride at an initial PGM concentration of 0.05 mol/m³. A sorption mechanism for PGMs was discussed based on the results.     

On the conservatism of the sum-of-squares method for analysis of time-delayed systems

In this paper, we present a converse Lyapunov result which shows that using polynomial Lyapunov functionals to prove the stability of linear time-delay systems is not conservative. This result motivates the sum-of-squares approach to stability analysis of linear time-delay systems. This main result is based on an extension of the Weierstrass approximation theorem to show that linear varieties of polynomials can be used to approximate linear varieties of the space of continuous functions.     

Sand Transport on Steeply Sloping Plane and Rippled Beds

Experiments on sand transport have been carried out in the Sloping Sediment Duct at HR Wallingford. The aim of the experiments was to investigate sediment transport mechanisms, for sand of varying degree of grading, on sloping beds. The Sloping Sediment Duct is a steady flow, recirculating duct, capable of generating mean flow speeds of up to 1 m/s and tilting to +/?30°. Twenty-two tests with two different sediments were conducted. Both sediments had a median grain size of about 0.23 mm but different standard deviations. Bed slopes up to +/?20° were used in the experiments. The results show that bedforms have a significant effect on the transport rate. Since the bedforms, in turn, are affected significantly by the slope, the relation between transport rate and slope is not a monotonic function. Maximum suspended transport rates were attained for downslope flows at angles of about 10°. The transport rate for widely graded sediment was significantly larger than that for well-sorted sediment for almost all flows and slopes.     

An Open Generic Corba-Programmable Videoconferencing Platform

In this paper we address the design and implementation of a generic terminal architecture for videoconferencing based on the principle of programmable protocol stacks. In this architecture, there exist two types of software components. A first type are the multimedia engines, which are responsible for handling the multimedia stream (execution layer). Secondly, the managing components handle the multimedia engines' lifecycles and provide a set of network- and codec-independent CORBA-IDL interfaces which make building the desired protocol stack straightforward (middleware based control layer). As a result, the developed platform can be easily integrated in existing multimedia control frameworks such as the TINA architecture or the H.323 terminal framework.     

Assessing alternative liquid fuels using net energy criteria

We summarise the changing circumstances of New Zealand's liquid fuel energy supply and propose an energetic methodology for assessing and ranking alternative sources of supply. A comparison between the traditional source of liquid fuels, imported petroleum, and one indigenous alternative source, ethanol from fodder beet, is used to describe the use of the energy ratio criterion. For this purpose, the process analysis mode of energy analysis is used. Basic conventions and assumptions used in energy analysis are described. The study reported in this paper provides an example in whicn economic and energetic analyses are compared for a specific project. From the results of the analysis, it appears that there would be advantages in moving towards a significant contribution from ethanol in New Zealand's liquid fuels future.