Creep in phosphorus alloyed copper during power-law breakdown

During the first phase of storage, creep will take place in the copper canisters in the KBS-3 package for nuclear waste. The temperatures are below 100 °C, and the creep is well inside the power-law breakdown regime. Creep models for this situation have been developed. The analysed material is pure copper with about 50 ppm phosphorus. Constitutive equations for creep and other plastic deformation have been set up based on a generalised Norton expression and Kocks-Mecking’s model for the back stress. A model for the minimum creep rate based on fundamental principles for climb and glide has been derived. This model gives the correct order of magnitude for the creep rate in the temperature range from 400 to 20 °C without the use of fitted parameters. The creep exponent varies from 5 to 105 in this interval. The constitutive equations have also been formulated for multiaxial stress states.     

BeTelGeuse: A Platform for Gathering and Processing Situational Data

BeTelGeuse is an extensible data collection platform for mobile devices, which also automatically infers higher level context from sensor data. In this article, the authors introduce BeTelGeuse's architecture and current features, and evaluate its impact on mobile phone performance.     

The effect of phosphorus on creep in copper

Pure copper with an addition of about 50 ppm phosphorus is the planned material for the outer part of the waste package for spent nuclear fuel in Sweden. Phosphorus is added to improve the creep ductility but it also strongly increases the creep strength. In the present paper the influence of phosphorus on the strength properties of copper is analysed. Using the Labusch-Nabarro model it is demonstrated that 50 ppm has a negligible influence on the yield strength in accordance with observations. For slow moving dislocations, the interaction energy between the P-atoms and the dislocations gives rise to an agglomeration and a locking. The computed break away stresses are in agreement with the difference in creep stress of copper with and without P-additions.     

A 250-Mbit/s ring local computer network using 1.3-µm single-mode optical fibers

A 250-Mbit/s three-station fiber-optic ring local computer network was built and successfully demonstrated. A conventional token protocol was employed for bus arbitration to maximize the bus efficiency under high loading conditions, and a non-return-to-zero (NRS) data encoding format was selected for simplicity and maximum utilization of the ECL-circuit bandwidth.     

Electroless deposition and silicidation of Ni contacts into p-type Porous Silicon

Porous Silicon (PS) has attracted much attention since the discovery of its photo luminescent behavior. It has also been used for various other applications such as electroluminescent light emitting-diodes (LEDs), photodetectors and solar cells. For such devices, it is important to make good metallic Ohmic contacts to the PS in order to maximize the efficiency. In order to produce buried contacts, barrier layers, Schottky devices, etc. in PS, it is advantageous to deposit metal that covers not only the surface of the porous layer, but also the inside walls and the bottom of the pores. In this work experiments were performed to examine the morphology and properties of electroless deposition of Nickel into p-type PS and subsequent formation of Nickel silicide after heat treatment. Circular PS samples of 6 mm diameter were produced by anodizing p-type Silicon wafers for 15 min and were subsequently plated with Ni using three different plating baths. The pores are on average 20 μm deep and 4 μm wide. Two samples of each type were heat treated in an nitrogen atmosphere for one hour at 400 and 600°C respectively to produce Nickel silicide. Reference samples were made by means of electron beam evaporation of Ni. SEM micrographs show that the best pore coverage was achieved using the Ni plating bath containing hypophosphite. I–V characterization shows that different rectifying and Ohmic contacts can be formed between electroless deposited Ni and PS depending on the conditions of the heat treatment. XRD and EDX characterizations show that both the NiSi and Ni₂Si phases exist in the sample at the same time.      

A COVQ-based image coder for channels with bit errors and erasures

We illustrate how channel optimized vector quantization (COVQ) can be used for channels with both bit-errors and bit-erasures. First, a memoryless channel model is presented, and the performance of COVQ's trained for this channel is evaluated for an i.i.d. Gaussian source. Then, the new method is applied in implementing an error-robust sub-band image coder, and we present image results that illustrate the resulting performance. Our experiments show that the new approach is able to outperform a traditional scheme based on separate source and channel coding.     

Reducing the total discharge from a large WWTP by separate treatment of primary effluent overflow.

At many large wastewater treatment plants (WWTPs) the increased hydraulic load, caused by combined sewer systems during storm events, results in primary effluent overflow when the capacity of further treatment is exceeded. Due to stringent effluent standards, regulating the total discharge from the WWTPs, the Rya WWTP in G?teborg and the Sj?lunda WWTP in Malm? will have to reduce the impact of primary effluent overflow. Separate, high rate, precipitation processes operated only during high flow conditions have been investigated in pilot units at the two WWTPs. Precipitation in existing primary settlers operated at a surface loading of 3.75 m/h removed phosphorus to 0.35 mg/l. The Actiflo process was also shown to remove suspended solids and phosphorus well. BOD was reduced by 50-60%. With such processes the overall effluent concentrations from the plants can be reduced significantly. Key upgrading features are small footprints, short start up time and high efficiency.