The effect of mechanical grinding on the mesoporosity of steam‐activated palm kernel shell activated carbons

BACKGROUND: Palm kernel shell activated carbon (OPSA) produced by steam gasification at high temperatures generally results in high surface areas of 1146 to 1600 m² g^?1, attributed to the high volume of micropores (0.43 to 0.56 cm³ g^?1). The mesoporosity of naturally occurring activated carbons is observed to increase with decreasing particle size. Mechanical grinding was therefore performed to investigate its effect on the mesoporosity and microporosity of OPSA. RESULTS: Mechanical grinding had a strong effect on mesopore volume and average pore diameter, with an increase in mesopore volume from 47 to 66% as particle size decreases. Interestingly, no significant effect on the micropore fraction was observed in ground OPSA particles. CONCLUSIONS: The mechanically ground OPSA particles possessed dual adsorption capabilities due to the high microporosity and moderate mesoporosity contained in the structures. This results in interesting porosity behaviour of palm kernel shell activated carbons and the potential to provide materials of distinct sorption capacities with minimal treatment. Copyright © 2009 Society of Chemical Industry     

Learning art with computers — a LISREL model

Abstract This paper surveys the attitudes on the use of computers for aesthetic communication. In spite of the proliferation of computer art software and the popularity of art galleries on the world-wide web, many artists still find it difficult to accept computer art as a form of art. Many of them find only commercial values in computer art. To understand the latent attitudes constituting this rejection, a survey was conducted among high school students and the data was analysed with LISREL structural equation modelling techniques. Results indicate that aesthetic concerns, conservatism, and stereotypes are the major factors accounting for the negative attitude. Implications for system design to overcome the negative attitudes are discussed.     

Experimental study of a microstrip patch antenna with an L-shapedprobe

The L-shaped probe is shown to be an attractive feed for the thick microstrip antenna (thickness around 10% of the operating wavelength). A parametric study on the rectangular patch antenna is presented. It is found that the antenna attains 36% impedance bandwidth (SWR⩽2) as well as gain bandwidth and about 7-dBi average gain. A two-element array fed by L-probes is also proposed. Experiments show that the array design can substantially suppress the cross polarization of the proposed antenna. Both the antennas have stable radiation patterns across the passband. Moreover, the measured resonant frequencies of the proposed antenna agree well with an existing formula and the L-probe does not have much effect on the resonant frequency     

Single‐cell‐gap transflective liquid‐crystal display using double‐ and single‐mode approaches

Abstract— In this paper, many popular methods to study transflective liquid‐crystal‐displays (LCDs) have been discussed, and several new transflective LCD configurations with a single‐cell gap have been proposed. The traditional double‐cell‐gap method gives the best match of the transmittance/reflectance voltage curve (TVC/RVC) and also the widest viewing angle, but also brings the highest fabrication complexity. The single‐cell‐gap transflective LCD is much easier to fabricate and also shows a good match of TVC/RVC. A new methodology has been shown to find optimal configurations for single‐cell‐gap transflective LCDs. New configurations using multimode in a single pixel include twisted nematic (TN) optically compensated bend (OCB), TN electrically controlled birefringence (ECB), and TN low‐twisted nematic (LTN). TN and hybrid‐aligned nematic (HAN) modes have been investigated for single‐mode transflective LCDs. The results exhibit high contrast ratio, a good match of TVC/RVC, as well as wide viewing angle.     

Web Applications in the Product Introduction Process (WAPIP)

There has been widespread interest in the development and application of the World Wide Web (WWW) to support decision-making activities in product design and manufacture. An increasing number of web applications are emerging and a large number of practitioners are trying these web-based decision support systems. In the meantime, it becomes increasingly difficult to surf for appropriate web applications on the Internet using general-purpose search engines. This paper describes a web site, WAPIP, that has been developed specifically to support new product introduction activities. It provides databases for software vendors and researchers to register their web applications with the WAPIP search engine. It also provides facilities to support practitioners in product design and manufacture to search rapidly for the web applications that are suitable for solving their problems. This paper discusses the various issues regarding the design, development and operation of this WAPIP search engine.     

Synchronised Web Applications for Product Development in the 21st Century

Product development continues to be at the core of manufacturing industries and the heartland of global competition in the 21st century. The e-commerce technologies will have a profound impact on the practice and performance of product development. This paper examines the roles of web applications in collaborative product design and manufacture. The emphasis is placed not only upon the geographical and disciplinary dimensions, but also on the time dimension of collaboration. A case study is used to demonstrate how synchronised web applications can be used to facilitate collaborative product definition. The project team members share the common work-space that maintains the integrity and consistency of product and process information.     

5-HT 1A and 2A receptor positive cells in the cerebella of mice and human and their decline during aging

This study evaluated the 5-HT1A and 5-HT2A receptor positive cells in the cerebella of mice and human by immunocytochemistry. Mice were of ages 1, 3, and 12 months whereas the human subjects were divided into two groups, a younger 57–78 years old group and an older 82–91 years old group. Both 5-HT1A and 5-HT2A receptor positive cells were observed in the molecular and granular layers of the cerebella of mice and human. Although there was a decline in these positive cells during aging, no regional difference in the positive cells were observed in the anterior, middle, and posterior regions of the cerebella. Microsc. Res. Tech. 2009. © 2009 Wiley-Liss, Inc.     

Small circularly polarised folded patch antenna

A small circularly polarised (CP) patch antenna with dual T-shaped probe feeds is presented. The patch is folded like a cap to generate a CP wave as well as to reduce the size of the antenna. The proposed antenna is operated at the centre frequency of 2.28 GHz with circular polarisation. The impedance bandwidth (SWR<2) is 21.8% from 2 to 2.49 GHz and the axial ratio bandwidth (AR<3 dB) is 3.5%. The measured gain is around 7.5 dBi. The antenna shows a good CP performance with a symmetric radiation pattern. The total area of reduction is 54% in comparison with the conventional half-wave patch antenna.     

High-gain and wide-band single-layer patch antenna for wireless communications

A technique employing the use of parallel feeds is applied to the recently proposed L-probe coupled patch antenna design. By employing only two L-probes, with proper separation, for feeding one single patch, a twin-L-probe coupled patch antenna is designed with both high-gain (10 dBi) and wide-band [25%, standing wave radio (SWR) /spl les/ 1.5] characteristics. In addition, the 1-dB-gain bandwidth is around 26%, which covers the impedance bandwidth. Furthermore, a noticeable suppression of cross-polarization radiation is observed. Simulation results are in good agreement with those noteworthy characteristics obtained from experiments. The proposed antenna is suitable for modern mobile communication applications.     

Optical properties of rare-earth doped epitaxial Sr0.5Ba0.5Nb2O6 thin films grown by pulsed laser deposition

Optical quality rare-earth (RE) (Nd³⁺, Eu³⁺, Gd³⁺ and Yb³⁺) doped Sr_0.5Ba_0.5Nb₂O₆ (SBN) epitaxial films of ~ 170 nm thick have been successfully grown on MgO (100) single crystal substrates using pulsed laser deposition technique. Strong residual stress in these films has been revealed by Raman spectroscopic studies. Two kinds of in-plane orientations with respect to the MgO substrate co-exist. All the film samples show high transparency in the visible wavelength. Their band-gap energies appear to be independent of the types of dopant. Photoluminescence (PL) spectra of RE-doped SBN ceramics show a strong and broad emission band at around 600 nm (2.07 eV). The peak position of this emission band changes slightly with different RE-dopants. Thin film samples, however, yield a broad PL band at around 385 nm (3.22 eV). This UV emission shows no observable shift in the peak position for different dopants. Apart from these broad emission bands, conspicuous emission lines from Eu³⁺ and Nd³⁺ ions are also noted. The origins of these PL spectra are discussed.