Using rainbow net simulation to measure fault tolerance in a multiprocessor

The Rainbow net simulation technique is applied to modelling the impact of system load and fault handling on the availability of a fault-tolerant multiprocessor architecture. Rainbow nets are described along with the motivation for creating this modelling technique. A Rainbow net fault-handling model is created for the fault-tolerant multiprocessor architecture and the topology is shown to remain constant in size, independent of the number of processor, memory and I/O elements configured in the system. Simulation is performed with a varying load in terms of the number of active jobs the system must support. Results are given showing how the fault-tolerant capability varies with load. Two new metrics for evaluating fault tolerance are introduced; namely full fault-tolerability and partial fault-tolerability. They are based on simple observations in the model.     

Water absorption properties of phosphate glass fiber‐reinforced poly‐ϵ‐caprolactone composites for craniofacial bone repair

The moisture uptake of polymers and composites has increasing significance where these materials are specified for invasive, long‐term medical applications. Here we analyze mass gain and the ensuing degradation mechanisms in phosphate glass fiber reinforced poly‐?‐caprolactone laminates. Specimens were manufactured using in situ polymerization of ?‐caprolactone around a bed of phosphate glass fibers. The latter were sized with 3‐aminopropyltriethoxysilane to control the rate of modulus degradation. Fiber content was the main variable in the study, and it was found that the moisture diffusion coefficient increased significantly with increasing fiber volume fraction. Diffusion, plasticization, and leaching of constituents appear to be the dominant aspects of the process over these short‐term tests. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Anion Sensing Porphyrin Functionalized Nanoparticles

Disulfide and dithiocarbamate functionalized porphyrins have been synthesized and used as protecting ligands for gold nanoparticle formation either via ligand substitution reactions or by direct synthesis. These nanoparticles have been shown to recognize anions via changes in the absorbance spectrum of the surface adsorbed porphyrin moieties. Association constants, derived from quantitative titrations, indicate a remarkable surface enhancement effect where the surface bound porphyrins bind anions much more strongly than the free receptor in solution.     

The segmented bidirectional single-loop topology for material flow systems

This paper introduces the segmented bidirectional single-loop (SBSL) flow topology for carrier-based material handling systems. This configuration is based on a single-loop flow-path structure that is divided into non-overlapping segments, each containing a single carrier operating in a bidirectional mode. The design procedure comprises a 0 - 1 mixed-integer formulation to determine the single-loop including the pickup and delivery station location. The second stage is a segmentation procedure to determine the non-overlapping segments in the loop. Finally the performance of the SBSL is evaluated by means of simulation.     

Effects of growth with ethanol on fermentation and membrane fluidity of Saccharomyces cerevisiae

Saccharomyces cerevisiae HSc was grown with ethanol at concentrations up to 10% (v/v). The immediate effects of additions of externally added ethanol on CO₂ production and O₂ consumption of washed organisms were studied by stopped-flow membrane inlet quadrupole mass spectrometry. Fermentative activities of organisms grown with ethanol (0–5% v/v) showed similar sensitivities to inhibition by ethanol, whereas those grown with 10% (v/v) ethanol had become protected and were markedly less sensitive. The fluidity of subcellular membrane fractions was measured by determination of the temperature dependence of the rotational order parameter of the spin label 5-doxyl stearic acid (free radical) by electron spin resonance. Mitochondria prepared from yeasts grown with 0, 7 and 9% (v/v) ethanol showed similar overall fluidity, although differences in temperature-dependent behaviour indicate altered lipid composition or lateral phase separations. On the other hand the microsomal fraction from organisms grown with 9% ethanol showed a remarkable increase in fluidity. These data suggest that the protective effects of growth with ethanol near the limit of tolerance on fermentative activities may arise from altered plasma membrane fluidity properties.