Speed control of brushless DC motor by adaptive network-based fuzzy inference

Microsystem Technologies - Brushless dc (BLDC) motor provides many advantages such as less power consumption, small volume, good stability, larger torque and simple control. As a result, the...     

Low-temperature synthesis of silicon carbide inert matrix fuel through a polymer precursor route

A low temperature process of mixing different sizes of silicon carbide (SiC) particles with a polymer precursor was utilized to synthesize SiC pellets for potential use as inert matrix fuels (IMF) for light water reactors. The lower temperature process is required to prevent the reactions between SiC and the dispersed PuO₂ fuel material. The effect of the polymer content and the cold pressing pressure on the packing of SiC particles was investigated. The effect of mixing coarse and fine SiC particles on the density and the pore size distribution was also investigated. It was found that the density and pore size distribution can be tailored by controlling the SiC size compositions, polymer content and pressing pressure at room temperature. A possible mechanism has been proposed to explain the forming of the pores with respect to the geometric arrangement between SiC particles and the polymer precursor. SEM images showed that ceria (cerium oxide) which is a PuO₂ surrogate in this study, was well distributed in the pellet.     

Green synthesis of porous Ni-silicate catalyst for hydrogen generation via ammonia decomposition

A simple synthetic method without organic template is proposed for the synthesis of Ni-silicate. The resulting Ni-phyllosilicates are reconstructed by hydrothermal treatment to a porous structure with a high surface area (552 m² g⁻¹). Notably, the residual filtrate has a Ni²⁺ ion content of less than 0.1 ppm, and therefore satisfies the effluent standard in Taiwan (<1.0 ppm). As a result, it can be disposed of directly without the need for additional treatment. The effects of the pH value and hydrothermal treatment time on the structure, morphology, and surface area of the Ni-silicate composites have been investigated. When applied to hydrogen production, the mesoporous Ni-silicate shows a high catalytic capability (>99%) toward ammonia decomposition at a temperature of 400°C. Overall, the proposed synthetic method is facile and easily extendable to the production of other metal-silicate materials for hydrogen generation.     

Mixed Broadcast Techniques of Leisure Information in Vehicular Ad-Hoc Networks

Telecommunication Systems - Vehicle-to-vehicle communication and probabilistic broadcast are important means for information dissemination in vehicular ad-hoc networks (VANETs). In contrast to...     

Background removal of multiview images by learning shape priors.

Image-based rendering has been successfully used to display 3-D objects for many applications. A well-known example is the object movie, which is an image-based 3-D object composed of a collection of 2-D images taken from many different viewpoints of a 3-D object. In order to integrate image-based 3-D objects into a chosen scene (e.g., a panorama), one has to meet a hard challenge--to efficiently and effectively remove the background from the foreground object. This problem is referred to as multiview images (MVIs) segmentation. Another task requires MVI segmentation is image-based 3-D reconstruction using multiview images. In this paper, we propose a new method for segmenting MVI, which integrates some useful algorithms, including the well-known graph-cut image segmentation and volumetric graph-cut. The main idea is to incorporate the shape prior into the image segmentation process. The shape prior introduced into every image of the MVI is extracted from the 3-D model reconstructed by using the volumetric graph cuts algorithm. Here, the constraint obtained from the discrete medial axis is adopted to improve the reconstruction algorithm. The proposed MVI segmentation process requires only a small amount of user intervention, which is to select a subset of acceptable segmentations of the MVI after the initial segmentation process. According to our experiments, the proposed method can provide not only good MVI segmentation, but also provide acceptable 3-D reconstructed models for certain less-demanding applications.     

Cell cycle-dependent tumor necrosis factor apoptosis

To determine if tumor necrosis factor (TNF)-mediated apoptosis affects cells at defined stages of the cell cycle, WEHI-164/2F (WEHI) cells were synchronized at G0-G1 after 3-day cultures in medium containing RPMI 1640 and 0.5% FCS (RPMI-0.5% FCS). The arrested WEHI cells (60-75% in G0-G1) showed increased sensitivity to TNF killing, measured as 48-h 3-(5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assays, and 15-h apoptosis by propidium iodide staining and flow cytometry analysis. The TNF killing kinetics of G0-G1-arrested cells was similar to controls, and TNF did not accelerate or retard cell cycle progression of the arrested cells after feeding with fresh RPMI-0.5% FCS. However, TNF inhibited WEHI DNA synthesis as early as 1 h after treatment, and inhibition was proportionate to sensitivity to TNF-induced apoptosis. WEHI cells treated with TNF showed a higher percentage of cells in S phase with concomitant decrease in G0-G1 and G2-M. When cultured for 3-18 h in fresh RPMI-0.5% FCS to allow progression of the G0-G1-arrested cells toward the G1-S boundary, WEHI cells became more sensitive to TNF killing, especially at the 3-9 h time points. Moreover, TNF did not degrade [125I]5-iodo-2'-deoxyuridine-labeled WEHI DNA if the labeled cells were precultured for 9 h in fresh RPMI-0.5% FCS to allow them to pass S phase before the addition of TNF. These results show that TNF-induced apoptosis of WEHI cells is connected to cell cycle events; WEHI targets receive the TNF cytotoxic signal mainly at the G1-S boundary and begin to die by apoptosis as they exit from S phase.     

Syngas chemical looping process: Dynamic modeling of a moving‐bed reducer

The syngas chemical looping process coproduces hydrogen and electricity with iron oxide based oxygen carriers in a circulating moving bed system. In this article, a one‐dimensional (1‐D) dynamic model is developed to simulate the countercurrent gas–solid reactive flow in the moving‐bed reducer. This model is validated by TGA and bench‐scale experiments. Both the steady state and dynamic composition profiles are obtained to help understand the reaction and reactor behaviors. Numerical simulation on the effects of reactor length is conducted to optimize the moving‐bed reducer design. It is also found that minor variations in the feed rate ratio near a critical point that is represented by the reaction equilibrium could yield a significant difference in the time required for the reactions to reach a steady‐state operation. Such a difference has an important practical implication in that the moving‐bed reducer should be designed and operated to circumvent the critical point. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3432–3443, 2013     

Computational models and experimental investigations of effects of balance and symmetry on the aesthetics of text-overlaid images

This article describes computational models based on principles of visual weights to compute the symmetry and balance of text-overlaid images. Two experiments were conducted to investigate the effects of symmetry and balance on the aesthetic appeal of text-overlaid images. In the first experiment, five color photos were used to compose a set of test images overlaid with a paragraph of Chinese texts as the stimuli. Contrastly, the second experiment applied monochrome photos to compute the stimuli. The positions of the text overlay were determined by varying the balance and symmetry in order to validate computational aesthetic quantification algorithms with subjective ratings. The stimuli were rated by 20 subjects in each experiment using the ratio-scale magnitude estimation method against a benchmark image for each photo. Results from both experiments show that subjects are adept at judging symmetry and balance in both the horizontal and vertical directions. Subjects are also adept at judging radial symmetry about the center point of an image. The experiments also established a relationship between a higher averaged visual balance and the aesthetic appeal of text-overlaid images. Symmetry in either direction, however, did not result in any proportional relations to the aesthetic appeal.