How far can one compress digital fault records? Analysis of a matching pursuit-based algorithm

In this paper, we verify how far electric disturbance signals can be compressed without compromising the analysis of encoded fault records. A recently proposed compression algorithm, referred to as Damped Sinusoidal Matching Pursuit (DSMP) has the remarkable feature of obtaining both compact and physically interpretable representations. However, for fault analysis applications, one is primarily interested in how accurate can be the analysis performed on compressed signals, instead of evaluating mean-squared error figures. Unlike previous works in digital fault records compression, the performance of the DSMP compression method is evaluated using a protocol based on fault analysis procedures commonly performed by expert engineers. This protocol is applied for comparing the results obtained in the analysis of both uncompressed records and their compressed versions at different compression ratios. The results show that the DSMP is a reliable compression system since it achieves high compression ratios (6.4:1) without causing fault analysis misinterpretation.     

Analysis of information exchange activities to actualize and validate situation awareness during shift changeovers in nuclear power plants

Shift work situations occur in almost all safety‐critical organizations, and the investigations of some catastrophes like Chernobyl, Exxon Valdez, and the Gol/Legacy mid‐air collision indicated that shift work information exchange played an important role during the evolution of the situation before the accidents. Inadequate communications during shift changeovers challenged operators' work in the moments that preceded these accidents, because they got inadequate information about the current situation. Our research focuses on the information exchange activities (verbal, written, and nonverbal) of nuclear power plant control operators during shift changeovers. Our aim is to investigate how verbal exchanges and other representations enable operator crews to share information regarding the events that occurred in the previous shift to achieve adequate situation awareness. Our findings indicated the importance and richness of the information exchange during the shift changeover process to update and validate individual and collective situation awareness, showing that information adequately shared enables the ad hoc configurations of regulation loops and a safer use of simplified strategies that can be understood and be validated by other operators, reducing the occurrence of cognitive overloads and contributing to the construction of a common cognitive ground that enhances system resilience. © 2010 Wiley Periodicals, Inc.     

Thermal expansion of Pyros from 20 to 1273 K

Pyros, which is a Ni-base alloy (82% Ni, 8% Cr, 4% W, 3% Mn, and 3% Fe), has been used extensively in France since 1926 as a temperature sensor and as a reference material for thermal expansion measurements. In this paper we present recent data on the expansion and expansivity of Pyros from 20 to 1273 K. Expansivity results, obtained by taking the derivative of a cubic-spline polynomial fitting performed to the L/L experimental data, show that Pyros is a stable material in the 20 to 1273 K temperature range. Furthermore, since the expansivity values are similar to those of steels, Pyros should be of special interest to laboratories which are concerned with expansion measurements on steels. Therefore, we suggest that Pyros be considered as a suitable reference material for thermal expansion measurements on steels, and until more accurate results are obtained, we propose our results as reference data between 20 and 1273 K.Paper presented at the Ninth Symposium on Thermophysical Properties, June 24–27, 1985, Boulder, Colorado, U.S.A.     

Consensus design of repeat proteins

Consensus design is a valuable protein-engineering method that is based on statistical information derived from sequence alignments of homologous proteins. Recently, consensus design was adapted to repeat proteins. We discuss the potential of this novel repeat-based approach for the design of consensus repeat proteins and repeat protein libraries and summarize recent results from such experiments.     

A generalized electromagnetic theory for the mass spectrum of neutrinos

In previous papers it was shown that solutions of Weyl equation that are eigenstates of the parity operator describe a coupled pair of a monopole anti-monopole system. These results suggest to seek a solution of the Maxwell equation $\partial F^\infty = - g\mathcal{J}$ with a current $\mathcal{J}$ as a source and such that the Lorentz force on the current is null. We first identify a solution where $J_m = - \gamma ^5 \mathcal{J}$ is a spacelike field. More surprisingly we find that there exists a solution F of the free Maxwell ? F = 0 that is equivalent to the inhomogeneous equation for F ^∞. Once this result is proved, it suggests by itself to seek more general (subluminal and even superluminal) solutions $\mathfrak{F}$ of the free Maxwell equation equivalent to an inhomogeneous Maxwell equation for a field $\mathfrak{F}_0$ with a current term as a source which may be a timelike or spacelike field. We exhibit one such subluminal solution, for which the Dirac-Hestenes spinor field ψ associated with the electromagnetic field $\mathfrak{F}_0$ satisfies a Dirac-like equation for a bradyonic neutrino under the ansatz that the current is $ce^{\lambda \gamma ^5 } g\psi \gamma ^0 \tilde \psi$ with g the quantum of magnetic charge and λ a constant to be determined in such a way that the auto-force is zero. Together with Dirac’s quantization condition this gives a quantized mass spectrum (Eq. (46)) for neutrinos, with masses of the different flavor neutrinos being of the same order of magnitude (Eq. (47)), which is in accord with recent experimental findings.     

Modeling of solid—liquid adsorption: Effects of adsorbent loads on model parameters

The adsorption of cobalt phthalocyanine dye onto activated carbon in a continuous stirred tank adsorber was studied. The variables investigated were: adsorbent mass, adsorbent particle size and fluid flowrate. Several models based on film, pore and surface diffusion were constructed and fitted to the experimental data. Experimental results showed: (i) the increasing importance of the film mass transfer resistance for increasing adsorbent loads; (ii) the increasing importance of the surface diffusion mechanism for increasing adsorbent loads; and (iii) the better discrimination among different models for higher adsorbent loads and lower flowrate.     

Degradation of Leaf Litter Phenolics by Aquatic and Terrestrial Isopods

To investigate species-specific decomposition rates of litter from native (Quercus faginea) and introduced (Eucalyptus globulus) tree species in Portugal, we monitored changes in the phenolic signature of leaf litter during decomposition as mediated by an aquatic, Proasellus coxalis (Isopoda: Asellota), and two terrestrial, Porcellio dispar and Eluma caelatum (Isopoda: Oniscidea), detritivores. Although the litter of Eucalyptus and Quercus did not differ in overall protein precipitation capacity, we detected differences in terms of contents of particular phenolic compounds and phenol oxidation products. Accordingly, we observed food-specific consumption rates in Proasellus, but not in the terrestrial isopods. Proasellus digested Eucalyptus at significantly higher rates than Quercus, whereas the opposite was the case for Eluma, and Porcellio digested both litter types equally well. Despite slight differences in detail, effects of Proasellus on changes in the signature of litter phenolics were similar for both litter types, whereas terrestrial isopods—Porcellio and Eluma, although they differed from each other—digestively degraded phenolic compounds in Eucalyptus and Quercus litter, respectively, in different ways. Overall, however, degradation of litter phenolics was similarly effective on both litter types. From these data, we conclude that decomposition of Eucalyptus litter does not proceed more slowly than of litter from native Portuguese trees.     

Water flux,DSC, and cytotoxicity characterization of membranes of cellulose acetate produced from sugar cane bagasse,using PEG 600

Summary In this article, cellulose acetate produced through the homogeneous acetylation of sugar cane bagasse cellulose was used to produce membranes, using poly(ethyleneglycol) 600 (PEG 600) as an admixture. The membranes were characterized using water flux measurements (Payne’s cup), differential scanning calorimetry (DSC) and neutral red uptake (cytotoxicity). The results showed that PEG 600 acts as a crystallinity inductor and/or pore former in the cellulose acetate matrix. The induction of crystallinity is important for this system since it had not been reported on the literature yet. The results also demonstrated that the studied membranes present a nontoxic behavior.     

Synthesis, characterization and crystal structure of a novel thiocyanate–ruthenium(II) complex

The cis-[Ru(dppb)(Me-bipy)(NCS)₂], dppb = 1,4-bis (diphenylphosphino)butane, Me-bipy = 4,4′-dimethyl-2,2′-bipyridine, and NCS = thiocyanate, was synthesized and characterized by spectroscopic and electrochemical techniques and its structure was determined by crystal X-ray analysis. The crystal structure reveals that the coordination geometry around the Ru(II) center is distorted octahedron where two molecules of thiocyanate are bonded to the ruthenium through nitrogen atom in cis orientation. The half-wave formal potential value E_1/2 = 0.8 V (versus Ag/AgCl) observed is considerable higher than that for the cis-[RuCl₂(dppb)(Me-bipy)] complex, E_1/2 = 0.6 V (versus Ag/AgCl), well illustrating the strong π-acceptor effect the NCS ligand toward the backbonding interaction with the Ru(II) metal center. The MLCT absorption bands of the thiocyanate complex present a higher molar absorptivity (about 12%) compared with the cis-[RuCl₂(dppb)(Me-bipy)] complex, in the same experimental conditions. These properties make the complex potentially promising for the photosensitization process.