High-T c superconducting Bi(Al)-Ca-Sr-Cu-O glass-ceramic fibres drawn from glass preforms

Bi(Al)-Ca-Sr Cu-O glass-ceramic fibres over 100 cm in length were successfully drawn from a glass preform above the crystallization temperature,T _x. The diameters of the uniformly drawn fibres with circular cross-section could be controlled in the range from 25–200 m and the drawing speed was as high as 200 cm min^–1. In this work Al₂O₃ was used to modify the properties of the glass. It increased the glass transition and crystallization temperatures but did not significantly increase the glass working range. Shrinkage and increase of density during heat treatment of the glass fibres were observed. The annealed (825°C/12 h in air) Bi₄Al_0.1Ca₃Sr₃Cu₄O_y glass-ceramic fibre showed aT _c(onset) of 82 K and aT _c(zero) of 71 K.     

‘WWW: World Wide Web or Wild Wild West?* fixing the fenceposts on the final frontier: Domain names,intellectual property paradigms and current disputes over the governance of the internet

This paper considers the current dispute over the appropriate legal relationship between domain names and trademarks in relation to present technical, political and economic agendas underlying various parties’ claims to Internet governance in this context. The mutual constitution of the Internet by its history and architecture has given rise to a huge range of interest groups with widely varying cultures, values and priorities. This paper contends that both the legal issues surrounding intellectual property rights in domain names and the arguments over the appropriateness of the proposed structures which have been recommended to govern domain name allocation by groups such as CORE and the US Dept of Commerce must be evaluated in this context.     

Possible On‐Line Methods of Removing Oxide Deposits from Inside Steam Generator Tubes

In an attempt to find an on‐line method to remove oxide deposited during normal operation on the primary side of a steam generator, a series of experiments was undertaken in a high temperature recirculating autoclave system. Alloy‐600 steam generator tubes removed from a CANDU nuclear reactor were monitored on‐line with a gamma spectrometer and the effects on them of transients in pH, oxidizing condition of the coolant and temperature, alone and in combination, were attempted. Only a chemical process—the addition of a mixture of ethylenediaminetetraacetic acid (EDTA) and citric acid—was effective in removing radioactivity and, therefore, oxide.     

Low bias dry etching of III-nitrides in Cl2-based inductively coupled plasmas

Cl₂-based inductively coupled plasmas (ICP) with low additional dc self-biases (?100V) produce convenient etch rates (500–1500Å·min^?1) for III-nitride electronic device structures. A systematic study of the effects of additive gas (Ar, N₂, H₂), discharge composition, process pressure, and ICP source power and chuck power on etch rate and surface morphology has been performed. The general trends are to go through a maximum in etch rate with percent Cl₂ in the discharge for all three mixtures, and to have an increase (decrease) in etch rate with source power (pressure). Since the etching is strongly ion-assisted, anisotropic pattern transfer is readily achieved. Maximum etch selectivities of approximately six for InN over the other nitrides were obtained.     

Stampede: a cluster programming middleware for interactive stream-oriented applications

Emerging application domains such as interactive vision, animation, and multimedia collaboration display dynamic scalable parallelism and high-computational requirements, making them good candidates for executing on parallel architectures such as SMPs and clusters of SMPs. Stampede is a programming system that has many of the needed functionalities such as high-level data sharing, dynamic cluster-wide threads and their synchronization, support for task and data parallelism, handling of time-sequenced data items, and automatic buffer management. We present an overview of Stampede, the primary data abstractions, the algorithmic basis of garbage collection, and the issues in implementing these abstractions on a cluster of SMPs. We also present a set of micromeasurements along with two multimedia applications implemented on top of Stampede, through which we demonstrate the low overhead of this runtime and that it is suitable for the streaming multimedia applications.     

Hydrodechlorination of chloroorganic compounds in ground water by palladium catalysts: Part 1. Development of polymer-based catalysts and membrane reactor tests

A polymer-based catalytic membrane reactor was developed and applied for hydrodechlorination of chlorobenzene as a model compound of ground and waste water contaminants. The catalytically active membrane consists of a non-porous, thin film (about 3–7 μm) of poly(dimethylsiloxane) (PDMS) loaded with nano-sized Pd clusters. They were built-in either directly or as nano-sized, supported catalysts. A composite membrane, consisting of porous poly(acrylonitrile) (PAN) support and a Pd-loaded thin PDMS film, was fabricated on a coating machine. Defect-free membrane envelopes of 0.1 m² were produced and fitted into a membrane test cell. Gaseous hydrogen as reductant for hydrodechlorination is fed from the membrane’s back side directly to the catalyst, embedded in the PDMS layer. The chemical reactions at the Pd surface are accompanied by absorption of chlorobenzene from the water phase into the PDMS layer and desorption of benzene and HCl back to the water phase. The specific activity of supported catalysts decreased only slightly by PDMS incorporation, e.g., from 31 l/g(Pd) min for Pd/Fe on titania to 16 l/g(Pd) min for the same catalyst built-in a 7 μm thick supported PDMS membrane and measured in the membrane test cell. Directly built-in Pd clusters are less active and more difficult to prepare on a larger scale. Some catalyst deactivation was observed and may be balanced by development of more suited nano-sized supported catalysts.     

A glass-bonded ceramic material from chrysotile (white asbestos)

A process has been developed for bonding chrysotile asbestos into a robust, dimensionally-stable lightweight ceramic material by fusing it with sodium silicate and/or ground waste glass. The chrysotile can retain its desirable properties of fibrous morphology and porosity, but the fibre bundles are stabilized by fusion into a glassy matrix, reducing the respirable fibre concentration. The glass-bonded materials have good resistance to mechanical abrasion, and any resulting dust is found by SEM to be particularly free of fibres. The thermal treatment also converts the chrysotile into crystalline forsterite, which should destroy its cell toxicity. Other methods of glass-bonding chrysotile compacts (hot pressing and impregnating with glaze) were also investigated, and the properties of the resulting materials are reported.     

Resistive upper critical field of single crystals of Tl2Ba2CuO6

We have measured the resistive upper critical field of overdoped single crystals of Tl₂Ba₂CuO₆ from the zero-field transition temperatureT _c (approximately 20 K) to temperatures as low as 12 mK, corresponding to less than 0.001T _c. In sharp contrast to the predictions of standard theories of superconductivity, the critical field is found to rise steeply with positive curvature as the temperature is reduced, and no sign of saturation is observed down to the lowest temperatures reached.     

Negotiation and conflict in large scale collaboration: a preliminary field study

Coordinating activities in many settings can require people to manage conflict, potential and actual. Conflict arises from resource limitations, high-stakes consequences, uncertainty, goal conflict among stakeholders and hierarchical organizational structures. To understand coordination in such systems, we conducted a field study of management of surgical operating rooms. While coordinating interdependencies, such as progress monitoring, scheduling and rescheduling, and prodding, coordinators managed a set of complicated conflicts. They did so opportunistically, to resolve and to prevent conflict. Additionally, coordinators were concerned with perceived fairness. These findings indicate that, in the design of ICT to support coordination, we should examine not only the mechanical articulation of activities and efficient prioritization of resources, but also means to support companion social processes.