Adhesion improvement of polyester/aluminium interface by plasma polymerization pretreatments

Plasma polymerizations (PP) of acrylic acid (AA) and methacrylic acid (MAA) on polyester were used to improve the adhesion of the polyester/aluminium interface. It was found that this adhesion measured by the peel test method is 5-10 times higher than in the case of untreated polyester. Comparisons of the X-ray photoelectron spectroscopy (XPS) results obtained from the treated polyester, the untreated polyester and the reference spectra of poly(acrylic acid) cast from H₂O suggest that the observed adhesion improvement can be explained in terms of the formation of new functionalities at the polyester surface.     

Evidence that type III iodothyronine deiodinase in rat astrocyte is a selenoprotein

A type III iodothyronine deiodinase (D-III) that inactivates thyroid hormones has been recently cloned and identified as a selenoprotein in neonatal rat skin. However, selenium (Se) deficiency does not affect the D-III activity in the rat placenta and decreases the D-III in the rat brain only slightly. This study examines the effect of Se on the D-III activity in cultures of rat brain astrocytes. Astrocytes were depleted in Se by maintaining them in Se-free chemically defined medium for 7 days. These conditions decreased the activity of a recognized selenoprotein, glutathione peroxidase, 3-10-fold. D-III activity induced by 12-0-tetradecanoylphorbol-13-acetate (TPA) was also decreased 2-6-fold. Addition of 30 nM Se to the culture medium caused a rapid increase in TPA-induced D-III activity visible within 1 h. This Se effect was maximal at 3 h (4-fold increase) and dose-dependent. Se also increased the induction of D-III by acidic Fibroblast Growth Factor, 8-bromo-cAMP, T4, or retinoic acid. Cycloheximide blocked the effect of Se on TPA-induced D-III activity, whereas actinomycin D did not. Thus the rapid effect of Se does not require messenger RNA synthesis but requires protein synthesis. We conclude that the D-III in astrocytes is probably a selenoprotein.     

A front remeshing technique for a Lagrangian description of moving interfaces in two‐fluid flows

The numerical analysis of two‐fluid flows involves the treatment of a discontinuity that appears at the separating interface. Classical Lagrangian schemes applied to update the front position between two immiscible incompressible fluids have been long recognized to provide a sharp representation of the interface. However, the main drawback of these approaches is the progressive distortion in the distribution of the markers used to identify the material front. To avoid this problem, an interface remeshing algorithm based on the diffuse approximation of the interface curvature is proposed in this work. In addition, the remeshed front is enforced to preserve the global volume. These new aspects are incorporated in an existing fluid dynamics formulation for the analysis of two‐fluid flows problems. The resulting formulation is called in this work as the moving Lagrangian interface remeshing technique (MLIRT). Copyright © 2005 John Wiley & Sons, Ltd.     

A tabu search heuristic for the routing and wavelength assignment problem in optical networks

This letter proposes a tabu search heuristic for solving the routing and wavelength assignment (RWA) problem in optical WDM networks, considering the wavelength continuity constraint and a given set of connections to satisfy. For a number of available wavelengths on each link, this algorithm attempts to maximize the number of routed connections. The algorithm has been implemented and tested on NSFNET and EONNET networks and comparisons have been done with other algorithms in terms of the blocking rate. Generally, the results obtained with our tabu search heuristic are better than those provided by these algorithms.     

Mental rotation and the identification of disoriented objects.

Compared the effects of stimulus orientation among 30 undergraduates across an object-naming task and a left–right decision task using the same line-drawing stimuli in a within-Ss design. Stimuli were shown at various orientations by rotating the objects in the picture plane. The effects of orientation on object-naming were different from those observed in the left–right task. Results suggest that 2 mechanisms are involved in the naming task, one of which is more sensitive to orientation effects. Results also suggest the possibility that one of the mechanisms underlying the effects of orientation on object-naming time may be mental motion. A list of the objects used in the experiment is appended. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reformulated Nyquist criterion for discrete-time systems

A reformulated Nyquist criterion for discrete time systems is generalized in two ways. First, the criterion is cast in a form which allows the user to assess, directly from the mapping, the range of a parameter that yields stability. Second, the criterion is extended to apply to the case where poles at z=∞ occur in the function being mapped     

Focused ion beam-shaped microtools for ultra-precision machining of cylindrical components

Focused ion beam (FIB) sputtering is used to shape a variety of cutting tools with dimensions in the 15–100 μm range and cutting edge radii of curvature of 40 nm. The shape of each microtool is controlled to a pre-specified geometry that includes rake and relief features. We demonstrate tools having rectangular, triangular, and other complex-shaped face designs. A double-triangle tip on one tool is unique and demonstrates the versatility of the fabrication process. The FIB technique allows observation of the tool during fabrication, and, thus, reproducible features are generated with sub-micron precision. Tools are made from tungsten carbide, high-speed tool steel, and single crystal diamond. Application of FIB-shaped tools in ultra-precision microgrooving tests shows that the cross-section of a machined groove is an excellent replication of the microtool face. Microgrooves on 40–150 μm pitch are cut into 3 mm diameter polymer rods, for groove arc lengths greater than 12 cm. The surface finish of machined features is also reported; groove roughness (R_a) is typically less than 0.2 μm. Ultra-precision machining of cylindrical substrates is extended to make bound metal microcoils having feature sizes of 20–40 μm.