Effects of the alumina scale on the room-temperature tensile behavior of preoxidized MA 956

This article deals with the effects of theα-Al₂O₃ scale (∼5μm) developed during preoxidation (1100 °C/100 hours) of MA 956 on its room-temperature tensile behavior. The tensile tests were made in the strain-rate range of 10⁻⁵ to 10⁻¹ s⁻¹. It is shown that the scale, fine and tightly adherent to the substrate, affects the tensile behavior in two relevant ways. First, the yield strength and the tensile strength are lowered with respect to those of the scale-free material. This is explained in terms of the residual stresses generated in the scale during preoxidation. From the analysis of the differences in the yield strength of preoxidized MA 956 with respect to the scale-free material, residual compression stresses in the scale of about 5500 MPa were obtained. These high stresses account for the surprisingly high tensile strain achieved (1.4 pct) before scale spallation occurs. Second, a ductile to brittle transition (DBT), which is not observed in the scale-free samples, occurs at intermediate strain rates (10⁻³ s⁻¹). The brittle fracture is related to the increase of the triaxiality state in the substrate near the scale/metal interface.     

Apparel sizing using trimmed PAM and OWA operators

This paper is concerned with apparel sizing system design. One of the most important issues in the apparel development process is to define a sizing system that provides a good fit to the majority of the population. A sizing system classifies a specific population into homogeneous subgroups based on some key body dimensions. Standard sizing systems range linearly from very small to very large. However, anthropometric measures do not grow linearly with size, so they can not accommodate all body types. It is important to determine each class in the sizing system based on a real prototype that is as representative as possible of each class. In this paper we propose a methodology to develop an efficient apparel sizing system based on clustering techniques jointly with OWA operators. Our approach is a natural extension and improvement of the methodology proposed by McCulloch, Paal, and Ashdown (1998), and we apply it to the anthropometric database obtained from a anthropometric survey of the Spanish female population, performed during 2006.     

Effcient Handling of Lock Hand-off in DSM Multiprocessors with Buffering Coherence Controllers

Synchronization in parallel programs is a major performance bottleneck in multiprocessor systems. Shared data is protected by locks and a lot of time is spent on the competition arising at the lock hand-off. In order to be serialized, requests to the same cache line can either be bounced (NACKed) or buffered in the coherence controller. In this paper, we focus mainly on systems whose coherence controllers buffer requests. In a lock hand-off, a burst of requests to the same line arrive at the coherence controller. During lock hand-off only the requests from the winning processor contribute to progress of the computation, since the winning processor is the only one that will advance the work. This key observation leads us to propose a hardware mechanism we call request bypassing, which allows requests from the winning processor to bypass the requests buffered in the coherence controller keeping the lock line. We present an inexpensive implementation of request bypassing that reduces the time spent on all the execution phases of a critical section (acquiring the lock, accessing shared data, and releasing the lock) and which, as a consequence, speeds up the whole parallel computation. This mechanism requires neither compiler or programmer support nor ISA or coherence protocol changes. By simulating a 32-processor system, we show that using request bypassing does not degrade but rather improves performance in three applications with low synchronization rates, while in those having a large amount of synchronization activity (the remaining four), we see reductions in execution time and in lock stall time ranging from 14% to 39% and from 52% to 71%, respectively. We compare request bypassing with a previously proposed technique called read combining and with a system that bounces requests, observing a significantly lower execution time with the bypassing scheme. Finally, we analyze the sensitivity of our results to some key hardware and software parameters.     

HURP/HURBA: Zero-configuration hierarchical Up/Down routing and bridging architecture for Ethernet backbones and campus networks

Ethernet switched networks do not scale appropriately due to limitations inherent to the spanning tree protocol. Ethernet architectures based on routing over a virtual topology in which turns are prohibited offer improved performance over spanning tree, although in some cases suffer from excessive computational complexity. Up/Down routing is a turn prohibition algorithm with low computational complexity. In this paper we propose HURBA, a new layer-two architecture that improves Up/Down routing performance due to an optimization based on the use of hierarchical addressing, while preserving the computational complexity of Up/Down. The resulting architecture requires zero-configuration, uses the same frame format as Ethernet, allows upgrades by software update, and is compatible with 802.1D bridges by means of encapsulation. HURP protocol builds automatically a core with the interconnected HURP routing bridges and the standard bridges get connected to the edges in standard spanning trees. Simulations show that the performance of HURP, evaluated over various combinations of network topology and size, is close to the one of shortest path, is consistently better than that of Up/Down, and is equal or better than Turn Prohibition, with the advantage of having a lower complexity.     

Resistance of Fusarium sp spores to solar TiO2 photocatalysis: influence of spore type and water (scaling‐up results)

BACKGROUND: Common irrigation water disinfection methods, which may be unable to inactivate all types of pathogens or even become phytotoxic themselves, are not very effective in controlling phytopathogens. Water disinfection by photocatalysis is a promising irrigation‐water treatment for destroying phytopathogens without the drawbacks of conventional disinfection methods. Previous research has shown that solar photocatalytic technology can be used in the disinfection treatment of bacteria, protozoa and fungi, either through solar disinfection only. The purpose of this work was evaluate the TiO₂ photocatalysis process to inactivate Fusarium spores in distilled and well water. RESULTS: This paper reports on the ability of solar photocatalysis to inactivate Fusarium spores in a solar bottle reactor and in a new 60 L compound parabolic collector (CPC) prototype reactor. Inactivation of Fusarium sp spores by titanium dioxide (Degussa P25) was evaluated in distilled and natural well water. The experiments were carried out using 5 or 6 h exposure to natural sunlight at the Plataforma Solar de Almeria (Southeast Spain). The highest Fusarium spore inactivation rate during experiments was achieved with a 30 L min^?1 flow rate and 100 mg L^?1 TiO₂ concentration. Three different Fusarium spores (microconidia, macroconidia and chlamydospores) were individually evaluated to determine whether there were differences in resistance to the photocatalytic treatment. The results showed that chlamydospores were the most resistant, followed by macroconidia, and finally microconidia were the most sensitive. CONCLUSIONS: Microconidia, macroconidia and chlamydospores in distilled and well water were inactivated with TiO₂ slurry in a 60 L CPC photoreactor, demonstrating for the first time that it is possible to scale‐up photocatalytic treatment for use and reuse of water for irrigation. Copyright © 2010 Society of Chemical Industry     

Detection of Circulating Cancer Cells Using Electrocatalytic Gold Nanoparticles

A rapid cancer cell detection and quantification assay, based on the electrocatalytic properties of gold nanoparticles towards the hydrogen evolution reaction, is described. The selective labeling of cancer cells is performed in suspension, allowing a fast interaction between the gold nanoparticle labels and the target proteins expressed at the cell membrane. The subsequent electrochemical detection is accomplished with small volumes of sample and user‐friendly equipment through a simple electrochemical method that generates a fast electrochemical response used for the quantification of nanoparticle‐labeled cancer cells. The system establishes a selective cell‐detection assay capable of detecting 4 × 10³ cancer cells in suspension that can be extended to several other cells detection scenarios.     

Potential Use of Quantum Dots in Flow Cytometry

QDs may offer significant advantages in environmental and bead-based applications where the target cells need to be discriminated above background fluorescence. We have examined the possible applications of QDs for flow cytometric measurements (FCM) by studying their excitation - emission spectra and their binding to paramagnetic beads. We labelled beads with either QDs or a commonly-used fluorochrome (FITC) and studied their fluorescence intensity by FCM. Flow cytometric comparisons indicated that the minimum fluorophore concentration required for detection of QDs above autofluorescent background was 100-fold less than for FITC.