Theoretical analysis of some spectral multigrid methods

We develop a theoretical analysis of a multigrid algorithm applied to spectral element discretization of linear elliptic problems. For a 1-D problem with non-constant coefficients we prove essentially the independence of the two-level convergence factor with respect to both the degree of the polynomial approximation and the number of spectral elements. We also sketch some ideas for the analysis of the 2-D case when only one spectral element is involved.     

Numerical diffusion and the tracking of solute fields in system codes: Part III. Application to a boron dilution transient analysis in the AP600

A study of a pump restart scenario in the AP600 with an unborated coolant plug in two of the four cold legs is presented. It has been performed with TRAC-PF1/MOD2 coupled with a 3-dimensional core neutronics model based on the nodal expansion method (NEM), and high order boron tracking algorithms. These are based on ULTIMATE-QUICKEST for 1-dimensional components and a flux corrected method developed by Smolarckievicz in the 3-dimensional vessel in order to reduce the numerical diffusion inherent to the upwind method used by most system codes to solve the transport equations. No turbulent diffusion model was included in the calculation to produce more conservative results. The results show that reduction of the numerical diffusion yields predictions with a significantly reduced margin in the size of the unborated plugs allowed to form in the primary side piping. In addition, two pump restart strategies have been suggested by the results, which could substantially decrease the size of an unborated plug injected into the core, in case it was suspected to have formed in a primary loop.     

The N4C Joint

This paper discusses the discovery that four oblique prisms with a square cross section can intersect, forming a joint by means of a notch parallel to the horizontal plane. The use of this joint in new constructions is explored.     

Permeability optimization and performance evaluation of hot aerosol filters made using foam incorporated alumina suspension

Porous ceramic samples were prepared from aqueous foam incorporated alumina suspension for application as hot aerosol filtering membrane. The procedure for establishment of membrane features required to maintain a desired flow condition was theoretically described and experimental work was designed to prepare ceramic membranes to meet the predicted criteria. Two best membranes, thus prepared, were selected for permeability tests up to 700 degrees C and their total and fractional collection efficiencies were experimentally evaluated. Reasonably good performance was achieved at room temperature, while at 700 degrees C, increased permeability was obtained with significant reduction in collection efficiency, which was explained by a combination of thermal expansion of the structure and changes in the gas properties.     

Improvement of viral recombinant protein-based immunoassays using nanostructured hybrids as solid support

Protein adsorption onto solid surfaces is a complex process playing an important role in biological systems, being crucial to maintain the three-dimensional conformation during molecules interaction. Polymers hybrid network could be used to perform immunoassays with the required high level specificity. We have developed a novel route for incorporating recombinant protein from Bovine Herpesvirus into a network using as template Poly(vinyl alcohol) chemically tailored with five organosilanes followed by FTIR spectroscopy characterization. Protein expressed in E. coli was incorporated into hybrid network; all the PVA-hybrids interacted with this biomolecule and FTIR vibrational bands have endorsed the results. PVA hybrids modified with 3-(triethoxysilyl) propylisocyanate-TESPI presented the best result in the immunoassay, enhancing the sera specificity in comparison with the commercial microplate. We have successfully developed organic-inorganic hybrid based on PVA-silane to be used in serological tests with recombinant protein as a promising tool for the development and production new diagnostic assays.     

Structural changes in marinated fillets of gilthead sea bream (Sparus aurata L.) during vacuum storage at refrigerated temperature

Fillets of Sparus aurata were marinated in a mixture of salt (5.5%) and citric acid (48.9 g/kg) for 1 h, then vacuum packed and refrigerated for 1, 5, 16, and 21 d. Structural and ultrastructural parameters were evaluated in 6 specimens per time period. At day 1, the preservative solution appeared among the muscle fibers, thus increasing the interfibrillar spaces; cytoplasmic organelles were swollen and the sarcolemma-endomysium appeared very altered and electron-dense. At 5 to 10 d, the marinade solution had penetrated into the muscle fibers. The subsarcolemmal and intermyofibrillar spaces were dilated and granular lines of electron-dense material appeared among the fibers. From 16 d, broad interfibrillar spaces were occupied by granular material derived from denatured sarcolemma-endomysium and denatured myofibrils. Sarcomeres were already altered from initial stages, mainly at the I-band level. The Z-line also appeared disrupted. Such alterations were more severe from 10 d on, such that most of the sarcomeres showed disintegration of myofilaments.     

The effect of bone conduction microphone locations on speech intelligibility and sound quality

This paper presents the results of three studies of intelligibility and quality of speech recorded through a bone conduction microphone (BCM). All speech signals were captured and recorded using a Temco HG-17 BCM. Twelve locations on or close to the skull were selected for the BCM placement. In the first study, listeners evaluated the intelligibility and quality of the bone conducted speech signals presented through traditional earphones. Listeners in the second study evaluated the intelligibility and quality of signals presented through a loudspeaker. In the third study the signals were reproduced through a bone conduction headset; however, signal evaluation was limited to speech intelligibility only. In all three studies, the Forehead and Temple BCM locations yielded the highest intelligibility and quality rating scores. The Collarbone location produced the least intelligible and lowest quality signals across all tested BCM locations.     

Accurate analytical expressions for stripping voltammetry in the Henry adsorption limit

A strategy is developed to derive accurate analytical expressions for low-coverage cathodic stripping voltammetry. The procedure relies on the observation that diffusion affects the location of simulated voltammetric waves but not their shape, provided that physisorption of the analyte is negligible. As a proof of the generality of the proposed approach and having in mind the stripping of thiols, analytical solutions are derived for the cathodic stripping of monomers, dimers, and a mixture of monomers and dimers, whose reliability is proved by their comparison with numerically simulated voltammograms. Application to the deposition and reductive desorption of mercaptoacetic acid at a mercury electrode demonstrates that these approximate solutions can be used to get insights into the interfacial organization of incipient films. For this particular system, a transition from monomeric to dimeric behavior is identified upon increasing the thiol surface concentration. Further generalization of the proposed methodology is achieved by deriving an approximate analytical solution for thin-layer anodic stripping voltammetry, which is satisfactorily compared to the existing summation series solution.     

Supporting Ubiquitous IMS-based Teleconferencing Through Discovery and Composition of IMS and Web Components

Natural communication among people happens in flexible ways and is strongly affected by the users’ situation (such as communication tools available, user’s location, and user’s preferences). This situation or context information is seldom used to initiate communication sessions among users. Current communication systems are indifferent about users’ context, often require time consuming manual configurations and often result in conferencing tools not being easily accessible when needed. This leads to lower adoption of innovative communications services. IMS SIP (IP Multimedia Subsystem, Session Initiation Protocol) sessions allow users to access the session from different points of contact (home, office, etc.), however, IMS still requires a prior knowledge of all SIP components that might be used in a SIP session. Furthermore, IMS makes limited use of context information (mainly user-defined availability). To address these issues our research approach combines techniques from pervasive computing with IMS networking principles to facilitate compositions of communication sessions based on users’ context. We propose a platform and APIs for pervasive application development support to allow greater intelligence in IMS applications. We additionally provide mechanisms for IMS applications to apply their intelligence to the configuration of physical devices and web resources used to set up a conference. The innovations proposed in this paper are: (1) A new standard for intelligent IMS-based conferencing applications. (2) Application Development Interfaces (APIs) for a platform for pervasive computing. (3) An architecture for a pervasive IMS platform.