Improved tribo-mechanical behavior of CaP-containing TiO2 layers produced on titanium by shot blasting and micro-arc oxidation

The combination of shot blasting (SB) and micro-arc oxidation (or anodic oxidation—AO) in titanium surfaces was shown to provide enhanced conditions for cell differentiation and osseointegration than those provided by SB or AO alone. This study associated both methods aiming to attain titania layers on Ti with adequate tribo-mechanical features for bone implants. SB was performed using alumina particles, and titania layers were grown by AO using a CaP-based electrolyte. Mechanical properties and scratch resistance were characterized at nanoscale by instrumented indentation and nanoscratch, and correlated with morphological and microstructural changes (XRD, SEM, EDS, AFM, and profilometry). Analytical methods were employed to correct roughness and substrate effects on the indentation results. CaP-containing TiO₂ layers were produced on AO and SB + AO. The latter presented small pore size and inhomogeneous layer thickness and Ca/P ratios, caused by the non-uniform surface straining by SB that affects the oxide growth kinetics in the electrochemical process. Elastic modulus of SB + AO layer (37 GPa) were lower than the AO one (45 GPa); both of them were smaller than bulk Ti (130 GPa) and close to bone values. The hardness profiles of AO and SB + AO were similar to the substrate ones. Because of the improved load bearing capacity and unique layer features, the critical load to remove the SB + AO titania coating in scratch tests was three times as much or higher than in AO. Results indicate improved mechanical biocompatibility and tribological strength of anodic titania layers grown on sand blasted Ti surfaces.     

Nanoelectronic SET-based core for network-on-chip architectures

Nanoelectronics is a very promising step the world of electronics is taking. It is proved to be more efficient than the microelectronic approaches currently in use, mainly in terms of area and energy management. A Single-Electron Transistor (SET) is capable of confining electrons to sufficiently small dimensions, so that the quantization of both their charge and their energy is easily observable, making the SET's quantum mechanical devices. These features should allow building chips with a number of devices orders of magnitude greater than indicated by the roadmap still respecting area and power consumption restrictions. In this sense, Tera Scale Integrated (TSI) systems can be feasible in the future. A digital module, such as an arithmetic logic unit, completely implemented with SETs has already been proposed and validated by simulation. In this work a completely SET based network-on-chip (NoC) nanoelectronic core is proposed. Furthermore, a simple NoC architecture based on that nanoelectronic core is also evaluated. It is shown that the SET-based NoC has a promising performance considering parameters such as power consumption, area and clock frequency. A simple comparison of mesh NoC chip prototypes is shown.     

Fabrication of curved micro structures on photoresist layer

A novel fabrication process for micro patterns with curvature was introduced. The curved structures were made by compensating rectangular micro structures with liquid photoresist layer. Because of the surface tension of the liquid in micro scale, various shapes of meniscus can be made on the micro channels. The micro channels were made on the silicon substrate in advance, and then the liquid layer was coated on the micro channels. From the nature of liquid behavior, the curved patterns with smooth surface are obtained, which cannot be made easily with the conventional mechanical machining, as well as with the microfabrication processes, such as wet and dry etching. With this principle, it is expected that the smooth and curved surfaces can be made by simple processes and the results can be applied widely, such as optical patterns.     

Recovery of platinum, tin and indium from spent catalysts in chloride medium using strong basic anion exchange resins

This work describes a route for platinum recovery from spent commercial Pt and PtSnIn/Al₂O₃ catalysts using strong basic mesoporous and macroporous anion exchange resins (Cl⁻ form). The catalysts were leached with aqua regia (75 °C, 20-25 min). Platinum adsorption was influenced by the presence of other metals which form chlorocomplexes (tin, indium) and also base metals (aluminum). However, it was possible to overcome this fact by a sequential desorption procedure. Aluminum was selectively removed from the resins by elution with 3 mol L⁻¹ HCl. Platinum was desorbed passing 1 mol L⁻¹ Na₂S₂O₃ (pH 9). Tin was removed by elution with 0.1 mol L⁻¹ ascorbic acid. Indium was removed using 0.1 mol L⁻¹ EDTA as eluent. Desorption efficiency exceeded 99% for all metals. Metals were recovered in high yields (>98 wt%).     

Hybrid porous phosphate heterostructures as adsorbents of Hg(II) and Ni(II) from industrial sewage

Porous phosphate heterostructures (PPH), functionalized with different ratios of aminopropyl and mercaptopropyl groups, labelled as N(x=5,25,50)-PPH and S(x=5,25,50)-PPH, respectively, were tested as adsorbents for Ni(II) and Hg(II) found in industrial sewage from electroplating processes and button battery recycling. X-ray diffraction was used to study the structures. The specific surface area of the pristine material (PPH) was 620 m(2)g(-1), whereas the specific surface areas of the modified mercaptopropyl (S(5)-PPH) and aminopropyl (N(5)-PPH) were 472 and 223 m(2)g(-1), respectively. The adsorption data were fitted to a Langmuir isotherm model. The S(5)-PPH material was saturated by 120 mmol Hg(II) per 100g of material, whereas for Ni(II) adsorption, N(25)-PPH material displayed the highest adsorption with a saturation value of 43.5 mmol per 100g. These results suggest that functionalized PPH materials may be promising toxic metal scavengers and that they may provide an alternative environmental technology.     

An np‐control chart for inspection errors and repeated classifications

The np‐control chart has been used to monitor the conforming fraction in process production, and it is assumed that no classification errors occur during the inspection process. Increases in the sample size and/or the number of repeated classifications of the inspected items can reduce the impact of the classification errors. In this paper, an np ‐control chart is proposed, and the monitored statistics are based on the results of independent repeated classifications with classification errors during the inspection process. The aim of the proposed control chart is to have the same performance as a control chart without classification errors. Numerical examples illustrate the proposal. Copyright © 2011 John Wiley & Sons, Ltd.