Use of a transparent rabbit ear chamber in the study of biomaterials

Tests of biocompatibility are obligatory in the development of implants. Use of a polycarbonate transparent rabbit ear is a practical and relatively economical way of observing and documenting progressive interaction between potential prosthetic materials and granulation tissue. Fabrication of the chambers is technically straightforward and the surgical procedure involved in their insertion is simple and minimally invasive.     

Fluorimetric methods for the measurement of intermediate metabolites (lactate,pyruvate, alanine, β-hydroxybutyrate,glycerol) using a COBAS FARA centrifugal analyser

Intermediate products of the metabolism of glucose, fat and amino-acid are important in the evaluation of such metabolic disorders as diabetes mellitus, liver disease and metabolic acidosis. In the present study, methods for the measurement of intermediate metabolites (lactate, pyruvate, alanine, β-hydroxybutyrate and glycerol) have been adapted to a fast centrifugal analyzer: the COBAS FARA. Correlation coeffcients rangedfrom 0.90 to 0.99, compared to established manual spectrophotometric methods. Within-run coeffcients of variation (CVs) ranged between 2.9 and 8.8% at low levels, between 1.5 and 5.7% at medium levels and between 1.2 and 5.6% at high levels. Between-run CVs were between 4.0 and 15.0% at low levels, between 1.7 and 7.0% at medium levels and between 1.3 and 2.7% at high levels. These fluorimetric assays for the determination of intermediate metabolites on COBAS FARA (Roche) have a good sensitivity and precision, are less costly than manual methods and can be used on a routine basis.     

Optimization of a schottky barrier mixer diode in the submillimeter wave region

We have designed a mixer Schottky barrier diode (SBD) for use in the submillimeter wave region with a structure optimized for minimum noise temperature. The dependence of mixer noise temperature upon thickness and doping density of the epitaxial layer and diode diameter of SBDs was simulated within the framework of existing theories. Special care was taken to formulate the SBD current-voltage and capacitance-voltage relations in a way that correctly describes the behavior of real SBDs.     

United States Nuclear Regulatory Commission Research Program on molten core debris interactions in the reactor cavity

The NRC's Research Program on Core-Debris/Cavity Interactions comprises two principal elements: (1) an analytical effort focused primarily on development of computer codes needed to predict the potential consequences of risk-significant severe-accident scenarios; and (2) an experimental component to provide insights into the relevant phenomenological processes and to develop the experimental data base necessary for validation of the codes. The analytical activities at Sandia National Laboratories (SNL) focus primarily on refinement and validation of the CORCON and VANESA codes. Two major experimental activities are also based at SNL: (1) the large-scale SURC tests address the thermal-hydraulic phenomena in the cavity as well as aerosol release associated with prototypical core-melt materials in various types of concrete crucibles, while (2) the WITCH and GHOST experiments are concerned with aerosol generation and radionuclide release phenomena. A program of small-scale special-effects tests at Brookhaven National Laboratory (BNL) is coupled to a concomitant model-development and code-validation activity. In addition, measurements are being made at Battelle Columbus Laboratory (BCL) to augment the thermochemical data base needed in the VANESA code to permit refined radiological source-term predictions. The current scope and status of this research is reviewed.     

General review of recent activities in acoustic emission technology in Italy

This paper describes the present situation in Italy in the field of Acoustic Emission researches and applications.Information on the level of instrumentation development is given. Both multichannel and multiparameter systems for large structure examination in real time and data logging systems for continuous surveillance purposes are considered.The expertise accumulated in the application of AE to pressure vessel examination during hydrotest is mentioned, this being oriented to pressure components of conventional power stations and chemical plants.Particular attention is recently paid to mechanical fatigue tests. These were conducted on intermediate PWR nuclear pressure vessel, reduced scale offshore nodes and full scale prototype aircraft.A considerable activity has been carried out on application of AE technique to the detection of fluid leakages in power plant components. Both intrusive and non-intrusive methods have been considered. Many boilers and pre-heaters of thermal power plants have been instrumented for an on-line AE monitoring during operation. The problem of the loose part monitoring has been also considered.Several basic researches for material characterization by AE have been also conducted. Different composite material, carbon and austenitic steels, metal alloys have been studied.     

Optimization of the test method for determining the bonding quality of core plywood (blockboard)

Over the last few decades, thanks mainly to their specific technological features and their stability of dimension and shape, wood-based panels have seen flourishing industrial and commercial development. Of these, blockboard consists of a central layer (core) made up of solid wood strips which is stiffened and bound together by glued, hot-pressed rotary cut veneers overlaid with grain (main wood fibre direction) perpendicular one to another. The panel made in this way is considered a distinct type of plywood. Although blockboard is widely used in furniture-making and carpentry in general, and plays an important role in the production of some EU countries, its physicalmechanical properties are largely unknown and the combination of wood components having very different thickness (strips and veneers) makes it difficult to precisely determine the bonding quality. The aim of this work is to contribute to setting up a testing method to objectively assess the above property as well as to achieve more efficient production process control. To this end the main testing methodologies, and in particular those on solid wood panels (prEN 13354), glulam (EN 392) and plywood (EN 314) were evaluated. The tension shear test seemed to be the most significant for assessing the actual resistance of the pair of glue lines bonding the wooden elements that make up the blockboard. In order to obtain symmetrical test pieces, the determination of the bonding quality also made it necessary to further glue two portions of the panel realizing a compound (5 layers) specimen whose core layer consisted of two overlaid veneers with parallel grain. Because of the encouraging results obtained, the method proposed has been included in the recent revision of the standard EN 314, the contents of which is also going to be adopted by ISO.

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Résumé Au cours des dernières décennies, grace surtout à leurs intéressantes caractéristiques technologiques et leur stabilité en matière de dimensions et de formes, les panneaux à base de bois ont enregistré un croissant développment industriel et commercial. L'un d'entre eux, le panneau latté, est constitué d'une couche centrale (ame) d'éléments en bois massif qui est rendue solidaire par la superposition, par collage et pressage à chaud, d'un placage avec direction des fibres perpendiculaires. Pour la composition susmentionnée, le panneau qui en dérive est considéré comme étant un type particulier de contre-plaqué. Bien que le panneau latté utilisé largement dans le secteur de l'ameublement et de la menuiserie en général, et qu'il occupe une place capitale dans le cadre de la production de plusieurs pays de l'UE, ses propriétés mécaniques sont peu connues, alors que la présence actuelle de composants en bois d'épaisseur très différente (liteaux et placages) rend difficile une détermination correcte de la qualité du collage. à ce propos, les principales méthodologies d'essai sur cet aspect ont été soigneusement évaluées, en particulier celles qui concernent les panneaux de bois massif (prEN 13354), le bois lamellé collé (EN 392) et le contre-plaqué (EN 314). L'essai de cisaillement par traction s'est révélé être le plus significatif pour évaluer la résistance effective des deux lignes de colle qui relient les éléments en bois composant le panneau. Toutefois, pour obtenir des éprouvettes symétriques, la détermination recherchée nécessite le collage de deux portions de panneau ce qui permet de réaliser une éprouvette composée (à cinq couches) dans laquelle la couche centrale est constituée par deux placages superposés avec direction des fibres parallèles. En considération des résultats obtenus, la méthodologie proposée a été introduite dans la révision de la norme EN 314, dont le contenu sera aussi adopté par l'ISO.