Graded evolution of anisotropic microstructure during sintering from crystal-oriented powder compact

Anisotropic sintering, including shrinkage and grain growth, was examined for c-axis-oriented (Sr,Ca)₂NaNb₅O₁₅ (SCNN) ceramics, which were prepared by colloidal processing under a magnetic field. In the c-axis-oriented SCNN powder compact, shrinkage and grain growth along the c-axis were higher than those along the a-axis. The anisotropic microstructural development was clearly associated with anisotropic sintering shrinkage. X-ray diffraction, scanning electron microscopy, and energy back scattering diffraction showed that the grain growth of oriented particles by including random grains contribute to the development of the oriented microstructure. Finally, the highly crystal-oriented SCNN ceramics with a densified microstructure were obtained through anisotropic sintering. These results clearly showed the potential to develop a well-defined anisotropic microstructure during sintering by designing and controlling the particle packing structure in a powder compact.     

Pilot Plant Study of Simultaneous Sewage Sludge Digestion and Metal Leaching

This research is related to a preindustrial pilot scale study of the performance of the simultaneous sewage sludge digestion and metal leaching (SSDML) process for decontamination and stabilization of sewage sludge. Ten batch tests were carried out in two 4?m3 bioreactors under various conditions of operation. Results indicated that the addition of 1.0 to 1.5?g?S0/L, which is the equivalent of approximately 30 to 50?kg?S0 per tons dry sludge, is sufficient to obtain conditions of acidity (pH<2.5) and oxido-reduction potential greater than 500 mV necessary for an effective solubilization of toxic metals. The final average of metal solubilization in the output sludge during the SSDML process varied in the following ranges: 25–78% Cd, 9–32% Cr, 48–100% Cu, 77–99% Mn, 15–53% Ni, 12–47% Pb, and 66–100% Zn. The N, P, and K contents were also preserved in the decontaminated sludge. Moreover, the use of low concentrations of elemental sulfur makes it possible to obtain decontaminated sludge with a low total sulfur content (1.4–1.5% S) compatible with agricultural use. The suspended solids removal calculated for the SSDML process was slightly lower, (2.5±0.4)% volatile suspended solids per day, than those reached using standard aerobic digestion. Finally, the SSDML process was found to be effective in removing bad odors and in the destruction (99–100%) of indicator bacteria.     

Performance of PKI-based security mechanisms in mobile ad hoc networks

Security for ad hoc network environments has received a lot of attention as of today. Previous work has mainly been focussing on secure routing, fairness issues, and malicious node detection. However, the issue of introducing and conserving trust relationships has received considerably less attention. In this article, we present a scalable method for the use of public key certificates and their revocation in mobile ad hoc networks (MANETs). With the LKN-ad hoc security framework (LKN-ASF) a certificate management protocol has been introduced, bringing PKI technology to MANETs. In addition a performance analysis of two different revocation approaches for MANETs will be presented.     

Does {charm} need depth? Similarity and levels-of-processing effects in cued recall.

Eich (1985) recently presented a distributed memory model in which the pattern of results used to support the levels-of-processing view of Craik and Lockhart (1972) was modeled by different degrees of similarity between the encoding context and the to-be-recalled item. We report two experiments in which both phonemic and semantic similarity were varied between pairs of words and incidental acquisition (rhyme vs. category judgments) was varied across the same pairs of items. In both experiments the manipulation of the acquisition task produced a difference in cued-recall performance for positive and negative rhyme and category judgments. Recall was better following a category encoding decision than following a rhyme decision. This difference was independent of the effects of similarity, which demonstrated that Eich's (1985) assumptions regarding the effects of similarity are not sufficient to account for the differences resulting from the manner in which subjects encode information. An alternative method of modeling the levels-of-processing effect within the framework of distributed memory models is proposed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multi-functional biochip for medical diagnostics and pathogen detection

We describe a multi-functional biochip (MFB), which uses two different types of bioreceptors, including nucleic acid and antibody probes, on a single platform. The multi-functional capability of the MFB device for biomedical diagnostics is illustrated by measurements of DNA probes specific to gene fragments of Bacillus anthracis and antibody probes targeted to Escherichia coli. Calibration curves for monitoring pathogenic species using antibody probes against E. coli and DNA probes for B. anthracis illustrate the capability of the device for medical diagnostics and for quantitative detection of pathogenic agents.     

Exit effect on hydrodynamics of the internal circulating fluidized bed riser

This is the first time an extensive investigation has been carried out regarding the effects of riser exit geometry on pressure drop and solid behaviour inside the Internal Circulating Fluidized Bed (ICFB) riser, using different riser exit geometries at several operating conditions.The Radioactive Particle-Tracking (RPT) technique was used for solid concentration measurements and solid residence time distribution at the exit zone. Experiments were conducted using Geldart B particles, in the gas superficial velocity range of 4 to 10 m/s. Axial solid hold-up, solid residence time distribution in the exit zone, and the reflux ratio factor k_m, (defined earlier by [E.H. Van der Meer, R.B. Thorpe, J.F. Davidson, Flow patterns in the square cross-section riser of a circulating fluidized bed and the effect of riser exit design, Chem. Eng. Sc. 55 (19) (2000) 4079-4099]), were the main criteria used to investigate the impact of gas-solid separator devices implemented at the ICFB riser exit.Solid residence time distribution results and axial solid hold-up profiles provided clear evidence that the separator device at the riser exit strongly influences the hydrodynamic structure of the ICFB riser. The V-shaped riser exit geometry was found to be the optimum of all the configurations studied.     

程控电流源无需电源支持

工程实验室通常都配有各种电源设备、伏特计、函数信号发生器和示波器。然而．许多这样的工程实验室却缺少电流源。这令人感到非常遗憾，因为电流源有助于生成I-V（电流对电压）曲线，它能对电池进行充放电操作，对电源设备预加负荷，并可实现许多其他的应用。     

Analysis of the Datagram Congestion Control Protocol’s connection management procedures using the sweep-line method

State space explosion is a key problem in the analysis of finite state systems. The sweep-line method is a state exploration method which uses a notion of progress to allow states to be deleted from memory when they are no longer required. This reduces the peak number of states that need to be stored, while still exploring the full state space. The technique shows promise but has never achieved reductions greater than about a factor of 10 in the number of states stored in memory for industrially relevant examples. This paper discusses sweep-line analysis of the connection management procedures of a new Internet standard, the Datagram Congestion Control Protocol (DCCP). As the intuitive approaches to sweep-line analysis are not effective, we introduce new variables to track progress. This creates further state explosion. However, when used with the sweep-line, the peak number of states is reduced by over two orders of magnitude compared with the original. Importantly, this allows DCCP to be analysed for larger parameter values. Somsak Vanit-Anunchai was partially supported by an Australian Research Council Discovery Grant (DP0559927) and Suranaree University of Technology. Guy Edward Gallasch was supported by an Australian Research Council Discovery Grant (DP0559927).     

Context-gated knowledge partitioning in categorization.

According to the knowledge partitioning framework, people sometimes master complex tasks by creating multiple independent parcels of partial knowledge. Research has shown that knowledge parcels may contain mutually contradictory information, and that each parcel may be used without regard to knowledge that is demonstrably present in other parcels. This article reports 4 experiments that investigated knowledge partitioning in categorization. When component boundaries of a complex categorization were identified by a context cue, a significant proportion of participants learned partial and independent categorization strategies that were chosen on the basis of context. For those participants, a strategy used in one context was unaffected by knowledge demonstrably present in other contexts, suggesting that knowledge partitioning in categorization can be complete. (PsycINFO Database Record (c) 2010 APA, all rights reserved)